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Is Hirschsprung disease a mendelian or a multifactorial disorder? | Coding sequence mutations in RET, GDNF, EDNRB, EDN3, and SOX10 are involved in the development of Hirschsprung disease. The majority of these genes was shown to be related to Mendelian syndromic forms of Hirschsprung's disease, whereas the non-Mendelian inheritance of sporadic non-syndromic Hirschsprung disease proved to be complex; involvement of multiple loci was demonstrated in a multiplicative model. | Hirschsprung disease (HSCR), or congenital intestinal aganglionosis, is a common
hereditary disorder causing intestinal obstruction, thereby showing considerable
phenotypic variation in conjunction with complex inheritance. Moreover,
phenotypic assessment of the disease has been complicated since a subset of the
observed mutations is also associated with several additional syndromic
anomalies. Coding sequence mutations in e.g. RET, GDNF, EDNRB, EDN3, and SOX10
lead to long-segment (L-HSCR) as well as syndromic HSCR but fail to explain the
transmission of the much more common short-segment form (S-HSCR). Furthermore,
mutations in the RET gene are responsible for approximately half of the familial
and some sporadic cases, strongly suggesting, on the one hand, the importance of
non-coding variations and, on the other hand, that additional genes involved in
the development of the enteric nervous system still await their discovery. For
almost all of the identified HSCR genes incomplete penetrance of the HSCR
phenotype has been reported, probably due to modifier loci. Therefore, HSCR has
become a model for a complex oligo-/polygenic disorder in which the relationship
between different genes creating a non-mendelian inheritance pattern still
remains to be elucidated. Hirschsprung's disease is characterized by the absence of ganglion cells in the
myenteric and submucosal plexuses of the gastrointestinal tract. Genetic
dissection was successful as nine genes and four loci for Hirschsprung's disease
susceptibility were identified. Different approaches were used to find these
loci such as classical linkage in large families, identity by descent mapping in
an inbred kindred, candidate gene approaches based on naturally occurring mutant
mice models, and finally the use of model-free linkage and association analyzes.
In this study, we review the identification of genes and loci involved in the
non-syndromic common form and syndromic Mendelian forms of Hirschsprung's
disease. The majority of the identified genes are related to Mendelian syndromic
forms of Hirschsprung's disease. The non-Mendelian inheritance of sporadic
non-syndromic Hirschsprung's disease proved to be complex; involvement of
multiple loci was demonstrated in a multiplicative model. We discuss the
practical implications of the elucidation of genes associated with
Hirschsprung's disease susceptibility for genetic counseling. Finally, we
speculate on possible strategies to identify new genes for Hirschsprung's
disease. The major gene for Hirschsprung disease (HSCR) encodes the receptor tyrosine
kinase RET. In a study of 690 European- and 192 Chinese-descent probands and
their parents or controls, we demonstrate the ubiquity of a >4-fold
susceptibility from a C-->T allele (rs2435357: p = 3.9 x 10(-43) in European
ancestry; p = 1.1 x 10(-21) in Chinese samples) that probably arose once within
the intronic RET enhancer MCS+9.7. With in vitro assays, we now show that the T
variant disrupts a SOX10 binding site within MCS+9.7 that compromises RET
transactivation. The T allele, with a control frequency of 20%-30%/47% and case
frequency of 54%-62%/88% in European/Chinese-ancestry individuals, is involved
in all forms of HSCR. It is marginally associated with proband gender (p = 0.13)
and significantly so with length of aganglionosis (p = 7.6 x 10(-5)) and
familiality (p = 6.2 x 10(-4)). The enhancer variant is more frequent in the
common forms of male, short-segment, and simplex families whereas multiple,
rare, coding mutations are the norm in the less common and more severe forms of
female, long-segment, and multiplex families. The T variant also increases
penetrance in patients with rare RET coding mutations. Thus, both rare and
common mutations, individually and together, make contributions to the risk of
HSCR. The distribution of RET variants in diverse HSCR patients suggests a
"cellular-recessive" genetic model where both RET alleles' function is
compromised. The RET allelic series, and its genotype-phenotype correlations,
shows that success in variant identification in complex disorders may strongly
depend on which patients are studied. Hirschsprung's disease (HSCR) is a fairly frequent cause of intestinal
obstruction in children. It is characterized as a sex-linked heterogonous
disorder with variable severity and incomplete penetrance giving rise to a
variable pattern of inheritance. Although Hirschsprung's disease occurs as an
isolated phenotype in at least 70% of cases, it is not infrequently associated
with a number of congenital abnormalities and associated syndromes,
demonstrating a spectrum of congenital anomalies. Certain of these syndromic
phenotypes have been linked to distinct genetic sites, indicating underlying
genetic associations of the disease and probable gene-gene interaction, in its
pathogenesis. These associations with HSCR include Down's syndrome and other
chromosomal anomalies, Waardenburg syndrome and other Domit sensorineural
deafness, the Congenital Central Hypoventilation and Mowat-Wilson and other
brain-related syndromes, as well as the MEN2 and other tumour associations. A
number of other autosomal recessive syndromes include the Shah-Waardenburg, the
Bardet-Biedl and Cartilage-hair hypoplasia, Goldberg-Shprintzen syndromes and
other syndromes related to cholesterol and fat metabolism among others. The
genetics of Hirschsprung's disease are highly complex with the majority of known
genetic sites relating to the main susceptibility pathways (RET an EDNRB).
Non-syndromic non-familial, short-segment HSCR appears to represent a
non-Mendelian condition with variable expression and sex-dependent penetrance.
Syndromic and familial forms, on the other hand, have complex patterns of
inheritance and being reported as autosomal domit, recessive and polygenic
patterns of inheritance. The phenotypic variability and incomplete penetrance
observed in Hirschsprung's disease could also be explained by the involvement of
modifier genes, especially in its syndromic forms. In this review, we look at
the chromosomal and Mendelian associations and their underlying signalling
pathways, to obtain a better understanding of the pathogenetic mechanisms
involved in developing aganglionosis of the distal bowel. |
List signaling molecules (ligands) that interact with the receptor EGFR? | The 7 known EGFR ligands are: epidermal growth factor (EGF), betacellulin (BTC), epiregulin (EPR), heparin-binding EGF (HB-EGF), transforming growth factor-α [TGF-α], amphiregulin (AREG) and epigen (EPG). | Autocrine, paracrine, and juxtacrine are recognized modes of action for
mammalian EGFR ligands including EGF, TGF-α (TGFα), amphiregulin (AREG),
heparin-binding EGF-like growth factor (HB-EGF), betacellulin, epiregulin, and
epigen. We identify a new mode of EGFR ligand signaling via exosomes. Human
breast and colorectal cancer cells release exosomes containing full-length,
signaling-competent EGFR ligands. Exosomes isolated from MDCK cells expressing
individual full-length EGFR ligands displayed differential activities; AREG
exosomes increased invasiveness of recipient breast cancer cells 4-fold over
TGFα or HB-EGF exosomes and 5-fold over equivalent amounts of recombit AREG.
Exosomal AREG displayed significantly greater membrane stability than TGFα or
HB-EGF. An average of 24 AREG molecules are packaged within an individual
exosome, and AREG exosomes are rapidly internalized by recipient cells. Whether
the composition and behavior of exosomes differ between nontransformed and
transformed cells is unknown. Exosomes from DLD-1 colon cancer cells with a
mutant KRAS allele exhibited both higher AREG levels and greater invasive
potential than exosomes from isogenically matched, nontransformed cells in which
mutant KRAS was eliminated by homologous recombination. We speculate that EGFR
ligand signaling via exosomes might contribute to diverse cancer phenomena such
as field effect and priming of the metastatic niche. BACKGROUND: In this study the total and phosphorylated amount of epidermal
growth factor receptor 1 (EGFR) and 2 (HER2) were measured together with EGFR
ligands in tissue samples of breast cancer patients in order to investigate
interrelations and possible prognostic values.
METHODS: Samples of maligt and non-cancer autologous reference tissue were
collected from 415 breast cancer patients. The tissue samples were cut and
either paraffin-embedded or homogenized in a lysis buffer to extract the
proteins. HER2 was measured using both immunohistochemistry (IHC)/fluorescence
in situ hybridization (FISH) and ADVIA Centaur. Phosphorylated HER2 and EGFR
(pHER2, pEGFR), total EGFR and the ligands: epidermal growth factor (EGF),
transforming growth factor-α (TGFα), amphiregulin (AREG), heparin-binding
EGF-like growth factor (HB-EGF), betacellulin (BTC) and epiregulin (EREG) were
measured using the Luminex.
RESULTS: The HER2 positivity rate was determined to be 25.2% by the Centaur
method vs. 15.8% by IHC and FISH. HER2, HB-EGF, TGFα and AREG were upregulated
in cancer tissue as compared with autologous reference tissue while EGFR, pEGFR
and EGF were downregulated (p<10-6). pEGFR in autologous reference tissue was
negatively correlated to the number of positive lymph nodes and to the tumor
size (p=0.0007 and p=0.001, respectively) and furthermore, decreased in the
group of mastectomy operated patients as compared with the lumpectomy group
(p<10-6). HB-EGF in cancer tissue was positively associated with high grade
tumors (p<10-6) and pHER2, HB-EGF and BTC were associated with poor disease free
survival (p=0.017, p=0.012 and p=0.0026, respectively).
CONCLUSIONS: Our study demonstrated a profound activation of the EGFR system.
HB-EGF was increased by factor 10 in cancer tissue and related to the biological
aggressiveness of the tumors, and pHER2, HB-EGF and BTC were associated with
poor clinical outcome. PURPOSE: Although KRAS mutation has been identified as a negative predictive
biomarker of anti-EGFR antibodies in metastatic colorectal cancer (mCRC), the
efficacy in mCRC patients with KRAS wild-type status remains limited. Anti-EGFR
antibodies work by blocking ligand binding, but the significance of EGFR ligands
in mCRC has not been completely described. This study was conducted to identify
the correlation between all seven EGFR ligands and clinical outcomes in mCRC
treated with anti-EGFR antibodies. Furthermore, we determined an appropriate
predictive strategy for anti-EGFR antibodies using these EGFR ligands.
METHODS: Among 36 mCRC patients who had been treated with cetuximab or
panitumumab, we identified 26 mCRC patients with wild-type KRAS status treated
properly as the second and further lines and analyzed the relationship between
immunoreactivity to seven EGFR ligands and clinical outcomes.
RESULTS: Good clinical outcomes were associated with immunoreactivity against
amphiregulin (AR), heparin-binding epidermal growth factor (HB-EGF),
transforming growth factor-α (TGF-α), and epiregulin (EREG). Further, patients
with immunoreactivity to greater than two of these four ligands (AR, HB-EGF,
TGF-α, and EREG) had significantly higher response rate (53.3 vs. 0.0 %, p =
0.004) and disease control rate (93.3 vs. 9.0 %, p = 0.00002) and longer
progression-free survival (median PFS: 231 vs. 79 days, p = 0.000008), when
compared with patients with immunoreactivity against zero or one ligand.
CONCLUSIONS: Immunohistochemical analysis of four EGFR ligands (AR, HB-EGF,
TGF-α, and EREG) might be a novel predictive biomarker and may help optimize
patient selection for cetuximab and panitumumab therapy in patients with mCRC. Prolidase, also known as Xaa-Pro dipeptidase or peptidase D (PEPD), is a
ubiquitously expressed cytosolic enzyme that hydrolyzes dipeptides with proline
or hydroxyproline at the carboxyl terminus. In this article, however, we
demonstrate that PEPD directly binds to and activates epidermal growth factor
receptor (EGFR), leading to stimulation of signaling proteins downstream of
EGFR, and that such activity is neither cell-specific nor dependent on the
enzymatic activity of PEPD. In line with the pro-survival and pro-proliferation
activities of EGFR, PEPD stimulates DNA synthesis. We further show that PEPD
activates EGFR only when it is present in the extracellular space, but that PEPD
is released from injured cells and tissues and that such release appears to
result in EGFR activation. PEPD differs from all known EGFR ligands in that it
does not possess an epidermal growth factor (EGF) motif and is not synthesized
as a transmembrane precursor, but PEPD binding to EGFR can be blocked by EGF. In
conclusion, PEPD is a ligand of EGFR and presents a novel mechanism of EGFR
activation. The epidermal growth factor receptor (EGFR) is a member of the receptor tyrosine
kinase family that plays a role in multiple cellular processes. Activation of
EGFR requires binding of a ligand on the extracellular domain to promote
conformational changes leading to dimerization and transphosphorylation of
intracellular kinase domains. Seven ligands are known to bind EGFR with
affinities ranging from sub-omolar to near micromolar dissociation constants.
In the case of EGFR, distinct conformational states assumed upon binding a
ligand is thought to be a determining factor in activation of a downstream
signaling network. Previous biochemical studies suggest the existence of both
low affinity and high affinity EGFR ligands. While these studies have identified
functional effects of ligand binding, high-resolution structural data are
lacking. To gain a better understanding of the molecular basis of EGFR binding
affinities, we docked each EGFR ligand to the putative active state
extracellular domain dimer and 25.0 ns molecular dynamics simulations were
performed. MM-PBSA/GBSA are efficient computational approaches to approximate
free energies of protein-protein interactions and decompose the free energy at
the amino acid level. We applied these methods to the last 6.0 ns of each
ligand-receptor simulation. MM-PBSA calculations were able to successfully rank
all seven of the EGFR ligands based on the two affinity classes:
EGF>HB-EGF>TGF-α>BTC>EPR>EPG>AR. Results from energy decomposition identified
several interactions that are common among binding ligands. These findings
reveal that while several residues are conserved among the EGFR ligand family,
no single set of residues determines the affinity class. Instead we found
heterogeneous sets of interactions that were driven primarily by electrostatic
and Van der Waals forces. These results not only illustrate the complexity of
EGFR dynamics but also pave the way for structure-based design of therapeutics
targeting EGF ligands or the receptor itself. Aberrant epidermal growth factor receptor (EGFR) expression promotes the
pathogenesis of maligt peripheral nerve sheath tumors (MPNSTs), the most
common maligcy associated with neurofibromatosis type 1, but the mechanisms
by which EGFR expression promotes MPNST pathogenesis are poorly understood. We
hypothesized that inappropriately expressed EGFRs promote MPNST invasion and
found that these kinases are concentrated in MPNST invadopodia in vitro.
Epidermal growth factor receptor knockdown inhibited the migration of
unstimulated MPNST cells in vitro, and exogenous EGF further enhanced MPNST
migration in a substrate-specific manner, promoting migration on laminin and, to
a lesser extent, collagen. In this setting, EGF acts as a chemotactic factor. We
also found that the 7 known EGFR ligands (EGF, betacellulin, epiregulin,
heparin-binding EGF, transforming growth factor-α [TGF-α], amphiregulin, and
epigen) variably enhanced MPNST migration in a concentration-dependent manner,
with TGF-α being particularly potent. With the exception of epigen, these
factors similarly promoted the migration of nonneoplastic Schwann cells.
Although transcripts encoding all 7 EGFR ligands were detected in human MPNST
cells and tumor tissues, only TGF-α was consistently overexpressed and was found
to colocalize with EGFR in situ. These data indicate that constitutive EGFR
activation, potentially driven by autocrine or paracrine TGF-α signaling,
promotes the aggressive invasive behavior characteristic of MPNSTs. The epidermal growth factor receptor (EGFR) is frequently expressed in
triple-negative breast cancer (TNBC) and is a marker of poor prognosis in this
patient population. Because activating mutations in this kinase are very rare
events in breast cancer, we screened breast tumor gene expression profiles to
examine the distribution of EGFR ligand expression. Of the six known EGFR
ligands, transforming growth factor alpha (TGFα) was expressed more highly in
triple-negative breast tumors than in tumors of other subtypes. TGFα is
synthesized as a transmembrane precursor requiring tumor necrosis factor alpha
converting enzyme (TACE)/ADAM17-dependent proteolytic release to activate its
receptor. In our study, we show that an inhibitor of this proteolytic release
blocks invasion, migration and colony formation by several TNBC cell lines. Each
of the effects of the drug was reversed upon expression of a soluble TGFα mutant
that does not require TACE activity, implicating this growth factor as a key
metalloproteinase substrate for these phenotypes. Together, these data
demonstrate that TACE-dependent TGFα shedding is a key process driving EGFR
activation and subsequent proliferation and invasion in TNBC cell lines. Intrahepatic cholangiocarcinoma (CCA) is characterized by an abundant
desmoplastic environment. Poor prognosis of CCA has been associated with the
presence of alpha-smooth muscle actin (α-SMA)-positive myofibroblasts (MFs) in
the stroma and with the sustained activation of the epidermal growth factor
receptor (EGFR) in tumor cells. Among EGFR ligands, heparin-binding epidermal
growth factor (HB-EGF) has emerged as a paracrine factor that contributes to
intercellular communications between MFs and tumor cells in several cancers.
This study was designed to test whether hepatic MFs contributed to CCA
progression through EGFR signaling. The interplay between CCA cells and hepatic
MFs was examined first in vivo, using subcutaneous xenografts into
immunocompromised mice. In these experiments, cotransplantation of CCA cells
with human liver myofibroblasts (HLMFs) increased tumor incidence, size, and
metastatic dissemination of tumors. These effects were abolished by gefitinib,
an EGFR tyrosine kinase inhibitor. Immunohistochemical analyses of human CCA
tissues showed that stromal MFs expressed HB-EGF, whereas EGFR was detected in
cancer cells. In vitro, HLMFs produced HB-EGF and their conditioned media
induced EGFR activation and promoted disruption of adherens junctions, migratory
and invasive properties in CCA cells. These effects were abolished in the
presence of gefitinib or HB-EGF-neutralizing antibody. We also showed that CCA
cells produced transforming growth factor beta 1, which, in turn, induced HB-EGF
expression in HLMFs.
CONCLUSION: A reciprocal cross-talk between CCA cells and myofibroblasts through
the HB-EGF/EGFR axis contributes to CCA progression. PURPOSE: The aim of this study was to investigate the biological and clinical
significance of epidermal growth factor receptor (EGFR) signaling pathway in
follicular dendritic cell sarcoma (FDC-S).
EXPERIMENTAL DESIGN: Expression of EGFR and cognate ligands as well as
activation of EGFR signaling components was assessed in clinical samples and in
a primary FDC-S short-term culture (referred as FDC-AM09). Biological effects of
the EGFR antagonists cetuximab and panitumumab and the MEK inhibitor UO126 on
FDC-S cells were determined in vitro on FDC-AM09. Direct sequencing of KRAS,
BRAF, and PI3KCA was conducted on tumor DNA.
RESULTS: We found a strong EGFR expression on dysplastic and neoplastic FDCs. On
FDC-AM09, we could show that engagement of surface EGFR by cognate ligands
drives the survival and proliferation of FDC-S cells, by signaling to the
nucleus mainly via MAPK and STAT pathways. Among EGFR ligands, heparin-binding
EGF-like growth factor, TGF-α and Betacellulin (BTC) are produced in the tumor
microenvironment of FDC-S at RNA level. By extending this finding at protein
level we found that BTC is abundantly produced by FDC-S cells and surrounding
stromal cells. Finally, direct sequencing of tumor-derived genomic DNA showed
that mutations in KRAS, NRAS, BRAF, and PI3KCA, which predicts resistance to
anti-EGFR MoAb in other cancer models, are not observed in FDC-S.
CONCLUSION: Activation of EGFR by cognate ligands produced in the tumor
microenvironment sustain viability and proliferation of FDC-S indicating that
the receptor blockade might be clinically relevant in this neoplasm. Based on gene expression patterns, breast cancers can be divided into subtypes
that closely resemble various developmental stages of normal mammary epithelial
cells (MECs). Thus, understanding molecular mechanisms of MEC development is
expected to provide critical insights into initiation and progression of breast
cancer. Epidermal growth factor receptor (EGFR) and its ligands play essential
roles in normal and pathological mammary gland. Signals through EGFR is required
for normal mammary gland development. Ligands for EGFR are over-expressed in a
significant proportion of breast cancers, and elevated expression of EGFR is
associated with poorer clinical outcome. In the present study, we examined the
effect of signals through EGFR on MEC differentiation using the human telomerase
reverse transcriptase (hTERT)-immortalized human stem/progenitor MECs which
express cytokeratin 5 but lack cytokeratin 19 (K5(+)K19(-) hMECs). As reported
previously, these cells can be induced to differentiate into luminal and
myoepithelial cells under appropriate culture conditions. K5(+)K19(-) hMECs
acquired distinct cell fates in response to EGFR ligands epidermal growth factor
(EGF), amphiregulin (AREG) and transforming growth factor alpha (TGFα) in
differentiation-promoting MEGM medium. Specifically, presence of EGF during in
vitro differentiation supported development into both luminal and myoepithelial
lineages, whereas cells differentiated only towards luminal lineage when EGF was
replaced with AREG. In contrast, substitution with TGFα led to differentiation
only into myoepithelial lineage. Chemical inhibition of the MEK-Erk pathway, but
not the phosphatidylinositol 3-kinase (PI3K)-AKT pathway, interfered with
K5(+)K19(-) hMEC differentiation. The present data validate the utility of the
K5(+)K19(-) hMEC cells for modeling key features of human MEC differentiation.
This system should be useful in studying molecular/biochemical mechanisms of
human MEC differentiation. BACKGROUND: Epidermal growth factor receptor (EGFR) activation plays a role in
colorectal cancer (CRC) carcinogenesis, and anti-EGFR drugs are used in
treatment of advanced CRC. One of the EGFR ligands is tumor-associated
trypsinogen inhibitor TATI, also called serine protease inhibitor Kazal type1
(SPINK 1), which we recently showed to be an independent prognostic marker in
CRC.
METHODS: We studied the prognostic value of immunohistochemical expression of
EGFR and concomitant expression of EGFR and TATI/SPINK1 in a series of 619
colorectal cancer patients.
RESULTS: Of the samples, 92% were positive for EGFR. EGFR+/TATI+ was seen in
62.8%, EGFR+/TATI- in 29.5%, EGFR-/TATI+ in 4.9%, and EGFR-/TATI- in 2.7% of
patients. EGFR expression correlated with WHO grade (p = 0.040). In univariate
analysis, EGFR expression correlated with favourable survival (p = 0.006).
EGFR+/TATI+ patients showed better survival than did those with other
combinations (p<0.001). In multivariate analysis, EGFR+/TATI+ was an independent
prognostic factor of favourable prognosis (p<0.001).
CONCLUSION: Concomitant positivity of EGFR and TATI/SPINK1 predicts favourable
prognosis in CRC. Pituitary adenylate cyclase-activating polypeptide (PACAP), a neuropeptide with
trophic and cytoprotective effects, has been shown to affect cell survival,
proliferation, and also differentiation of various cell types. The high PACAP
level in the milk and its changes during lactation suggest a possible effect of
PACAP on the differentiation of mammary epithelial cells. Mammary cell
differentiation is regulated by hormones, growth factors, cytokines/chemokines,
and angiogenic proteins. In this study, differentiation was hormonally induced
by lactogenic hormones in confluent cultures of HC11 mouse mammary epithelial
cells. We investigated the effect of PACAP on mammary cell differentiation as
well as release of cytokines, chemokines, and growth factors. Differentiation
was assessed by expression analysis of the milk protein β-casein.
Differentiation significantly decreased the secretion of interferon gammainduced
protein (IP)-10, "regulated upon activation normal T cell expressed and
presumably secreted" (RANTES), insulin-like growth factor-binding protein
(IGFBP)-3 and the epidermal growth factor receptor (EGFR) ligands, such as
epidermal growth factor (EGF) and amphiregulin (AREG). The changes in the levels
of IP-10 and RANTES may be relevant for the alterations in homing of T cells and
B cells at different stages of mammary gland development, while the changes of
the EGFR ligands may facilitate the switch from proliferative to lactating
stage. PACAP did not modulate the expression of β-casein or the activity of
hormone-induced pathways as determined by the analysis of phosphorylation of
Akt, STAT5, and p38 MAPK. However, PACAP decreased the release of EGF and AREG
from non-differentiated cells. This may influence the extracellular
signal-related transactivation of EGFR in the non-differentiated mammary
epithelium and is considered to have an impact on the modulation of oncogenic
EGFR signaling in breast cancer. |
Is the protein Papilin secreted? | Yes, papilin is a secreted protein | A sulfated glycoprotein was isolated from the culture media of Drosophila Kc
cells and named papilin. Affinity purified antibodies against this protein
localized it primarily to the basement membranes of embryos. The antibodies
cross-reacted with another material which was not sulfated and appeared to be
the core protein of papilin, which is proteoglycan-like. After reduction,
papilin electrophoresed in sodium dodecyl sulfate-polyacrylamide gel
electrophoresis as a broad band of about 900,000 apparent molecular weight and
the core protein as a narrow band of approximately 400,000. The core protein was
formed by some cell lines and by other cells on incubation with 1 mM
4-methylumbelliferyl xyloside, which inhibited formation of the
proteoglycan-like form. The buoyant density of papilin in CsCl/4 M guanidine
hydrochloride is 1.4 g/ml, that of the core protein is much less. Papilin forms
oligomers linked by disulfide bridges, as shown by sodium dodecyl
sulfate-agarose gel electrophoresis and electron microscopy. The protomer is a
225 +/- 15-nm thread which is disulfide-linked into a loop with fine, protruding
thread ends. Oligomers form clover-leaf-like structures. The protein contains
22% combined serine and threonine residues and 25% combined aspartic and
glutamic residues. 10 g of polypeptide has attached 6.4 g of glucosamine, 3.1 g
of galactosamine, 6.1 g of uronic acid, and 2.7 g of neutral sugars. There are
about 80 O-linked carbohydrate chains/core protein molecule. Sulfate is attached
to these chains. The O-linkage is through an unidentified neutral sugar. Papilin
is largely resistant to common glycosidases and several proteases. The degree of
sulfation varies with the sulfate concentration of the incubation medium. This
proteoglycan-like glycoprotein differs substantially from corresponding
proteoglycans found in vertebrate basement membranes, in contrast to Drosophila
basement membrane laminin and collagen IV which have been conserved
evolutionarily. Two contrasting substrates, Drosophila laminin and human vitronectin, caused
determined primary Drosophila embryo cells to follow alternate intermediate
differentiation steps without affecting the final outcome of differentiation.
Integrin alpha PS2 beta PS3 was essential for the initial spreading of myocytes
on vitronectin: focal contacts rich in beta PS3 integrins formed and were
connected by actin- and myosin-containing stress fibers. While alpha PS2 beta
PS3 was unnecessary for myotube formation on laminin, it was required for the
subsequent change to a sarcomeric cytoarchitecture. The differentiating primary
cultures synthesized integrins and assembled them into detergent-insoluble,
cytoskeleton-associated complexes. Collagen IV, laminin, glutactin, papilin, and
other extracellular matrix proteins were made primarily by hemocytes and were
secreted into the medium. Further differentiation within the cultures was
influenced by secreted components and by later addition of vitronectin or bovine
serum. Comparison of the differentiation of various cell types on the two
substrates showed that vitronectin provided a selective advantage for the
differentiation of myocytes, with enrichment over epithelia, epidermal cells,
and neurites. Papilin is an extracellular matrix glycoprotein that we have found to be
involved in, (1) thin matrix layers during gastrulation, (2) matrix associated
with wandering, phagocytic hemocytes, (3) basement membranes and (4)
space-filling matrix during Drosophila development. Determination of its cDNA
sequence led to the identification of Caenorhabditis and mammalian papilins. A
distinctly conserved 'papilin cassette' of domains at the amino-end of papilins
is also the carboxyl-end of the ADAMTS subgroup of secreted, matrix-associated
metalloproteinases; this cassette contains one thrombospondin type 1 (TSR)
domain, a specific cysteine-rich domain and several partial TSR domains. In
vitro, papilin non-competitively inhibits procollagen N-proteinase, an ADAMTS
metalloproteinase. Inhibiting papilin synthesis in Drosophila or Caenorhabditis
causes defective cell arrangements and embryonic death. Ectopic expression of
papilin in Drosophila causes lethal abnormalities in muscle, Malpighian tubule
and trachea formation. We suggest that papilin influences cell rearrangements
and may modulate metalloproteinases during organogenesis. Papilins are extracellular matrix proteins that share a particular, common order
of types of protein domains. They occur widely, from nematodes to man, and can
differ in the number of repeats of a given type of domain. Protein variety is
increased by differential splicing of pre-mRNA. We report that Drosophila, which
has a compact genome, expresses three splice variants of papilin during
embryogenesis in developmentally defined patterns. These isoforms have different
numbers of Kunitz and IgC2 domains. The papilin isoforms are expressed in
specific cell types and contribute to different extracellular matrices in
gastrulation folds, early mesoderm, heart formation, basement membranes, and
elaboration of the excorporeal peritrophic membrane that lines the gut. This
finding indicates an unexpectedly broad spectrum of different pericellular
matrices in Drosophila embryos. Such papilin-containing matrices have
developmental as well as functional significance, as we previously showed that
both suppression of papilin synthesis and ectopic overexpression lethally
disrupt organogenesis. The TSR superfamily is a diverse family of extracellular matrix and
transmembrane proteins, many of which have functions related to regulating
matrix organization, cell-cell interactions and cell guidance. This review
samples some of the contemporary literature regarding TSR superfamily members
(e.g. F-spondin, UNC-5, ADAMTS, papilin, and TRAP) where specific functions are
assigned to the TSR domains. Combining these observations with the published
crystal structure of the TSRs of thrombospondin-1 may hold a key to the
development of therapeutic agents for fighting parasitic infection and tumor
growth. Papilins are homologous, secreted extracellular matrix proteins which share a
common order of protein domains. They occur widely, from nematodes to man, and
can differ in the number of repeats of a given type of domain. Within one
species the number of repeats can vary by differential RNA splicing. A
distinctly conserved cassette of domains at the amino-end of papilins is
homologous with a cassette of protein domains at the carboxyl-end of the ADAMTS
subgroup of secreted, matrix-associated metalloproteases. Papilins primarily
occur in basement membranes. Papilins interact with several extracellular matrix
components and ADAMTS enzymes. Papilins are essential for embryonic development
of Drosophila melanogaster and Caenorhabditis elegans. The gonad arms of C. elegans hermaphrodites acquire invariant shapes by guided
migrations of distal tip cells (DTCs), which occur in three phases that differ
in the direction and basement membrane substrata used for movement. We found
that mig-6 encodes long (MIG-6L) and short (MIG-6S) isoforms of the
extracellular matrix protein papilin, each required for distinct aspects of DTC
migration. Both MIG-6 isoforms have a predicted N-terminal papilin cassette,
lagrin repeats and C-terminal Kunitz-type serine proteinase inhibitory domains.
We show that mutations affecting MIG-6L specifically and cell-autonomously
decrease the rate of post-embryonic DTC migration, mimicking a post-embryonic
collagen IV deficit. We also show that MIG-6S has two separable functions - one
in embryogenesis and one in the second phase of DTC migration. Genetic data
suggest that MIG-6S functions in the same pathway as the MIG-17/ADAMTS
metalloproteinase for guiding phase 2 DTC migrations, and MIG-17 is abnormally
localized in mig-6 class-s mutants. Genetic data also suggest that MIG-6S and
non-fibrillar network collagen IV play antagonistic roles to ensure normal phase
2 DTC guidance. OBJECTIVES: Suicidal ideation is an uncommon but worrisome symptom than can
emerge during antidepressant treatment. We have described earlier the
association between treatment-emergent suicidal ideation (TESI) and markers in
genes encoding glutamate receptor subunits GRIK2 and GRIA3. The present
genome-wide association study was conducted to identify additional genetic
markers associated with TESI that may help identify individuals at high risk who
may benefit from closer monitoring, alternative treatments, and/or specialty
care.
METHODS: A clinically representative cohort of outpatients with nonpsychotic
major depressive disorder enrolled in the Sequenced Treatment Alternatives to
Relieve Depression (STAR*D) trial were treated with citalopram under a standard
protocol for up to 14 weeks. DNA samples from 90 White participants who
developed TESI and a sex-matched and race-matched equal number of treated
participants who denied any suicidal ideas were genotyped with 109 365 single
nucleotide polymorphisms on the Illumina's Human-1 BeadChip.
RESULTS: One marker was found to be associated with TESI in this sample at the
experiment-wide adjusted P less than 0.05 level (marker rs11628713, allelic P =
6.2x10, odds ratio = 4.7, permutation P = 0.01). A second marker was associated
at the experiment-wide adjusted P = 0.06 level (rs10903034, allelic P = 3.02x10,
odds ratio = 2.7, permutation P = 0.06). These markers reside within the genes
PAPLN and IL28RA, respectively. PAPLN encodes papilin, a protoglycan-like
sulfated glycoprotein. IL28RA encodes an interleukin receptor.
CONCLUSION: Together with our earlier report, these findings may shed light on
the biological basis of TESI and may help identify patients at increased risk of
this potentially serious adverse event. Cell invasion through basement membrane is a specialized cellular behavior
critical for many developmental processes and leukocyte trafficking. Invasive
cellular behavior is also inappropriately co-opted during cancer progression.
Acquisition of an invasive phenotype is accompanied by changes in gene
expression that are thought to coordinate the steps of invasion. The
transcription factors responsible for these changes in gene expression, however,
are largely unknown. C. elegans anchor cell (AC) invasion is a genetically
tractable in vivo model of invasion through basement membrane. AC invasion
requires the conserved transcription factor FOS-1A, but other transcription
factors are thought to act in parallel to FOS-1A to control invasion. Here we
identify the transcription factor HLH-2, the C. elegans ortholog of Drosophila
Daughterless and vertebrate E proteins, as a regulator of AC invasion. Reduction
of HLH-2 function by RNAi or with a hypomorphic allele causes defects in AC
invasion. Genetic analysis indicates that HLH-2 has functions outside of the
FOS-1A pathway. Using expression analysis, we identify three genes that are
transcriptionally regulated by HLH-2: the protocadherin cdh-3, and two genes
encoding secreted extracellular matrix proteins, mig-6/papilin and
him-4/hemicentin. Further, we show that reduction of HLH-2 function causes
defects in polarization of F-actin to the invasive cell membrane, a process
required for the AC to generate protrusions that breach the basement membrane.
This work identifies HLH-2 as a regulator of the invasive phenotype in the AC,
adding to our understanding of the transcriptional networks that control cell
invasion. |
Are long non coding RNAs spliced? | Long non coding RNAs appear to be spliced through the same pathway as the mRNAs | Thousands of long noncoding RNAs (lncRNAs) have been found in vertebrate
animals, a few of which have known biological roles. To better understand the
genomics and features of lncRNAs in invertebrates, we used available RNA-seq,
poly(A)-site, and ribosome-mapping data to identify lncRNAs of Caenorhabditis
elegans. We found 170 long intervening ncRNAs (lincRNAs), which had single- or
multiexonic structures that did not overlap protein-coding transcripts, and
about sixty antisense lncRNAs (ancRNAs), which were complementary to
protein-coding transcripts. Compared to protein-coding genes, the lncRNA genes
tended to be expressed in a stage-dependent manner. Approximately 25% of the
newly identified lincRNAs showed little signal for sequence conservation and
mapped antisense to clusters of endogenous siRNAs, as would be expected if they
serve as templates and targets for these siRNAs. The other 75% tended to be more
conserved and included lincRNAs with intriguing expression and sequence features
associating them with processes such as dauer formation, male identity, sperm
formation, and interaction with sperm-specific mRNAs. Our study provides a
glimpse into the lncRNA content of a nonvertebrate animal and a resource for
future studies of lncRNA function. Splicing remains an incompletely understood process. Recent findings suggest
that chromatin structure participates in its regulation. Here, we analyze the
RNA from subcellular fractions obtained through RNA-seq in the cell line K562.
We show that in the human genome, splicing occurs predomitly during
transcription. We introduce the coSI measure, based on RNA-seq reads mapping to
exon junctions and borders, to assess the degree of splicing completion around
internal exons. We show that, as expected, splicing is almost fully completed in
cytosolic polyA+ RNA. In chromatin-associated RNA (which includes the RNA that
is being transcribed), for 5.6% of exons, the removal of the surrounding introns
is fully completed, compared with 0.3% of exons for which no intron-removal has
occurred. The remaining exons exist as a mixture of spliced and fewer unspliced
molecules, with a median coSI of 0.75. Thus, most RNAs undergo splicing while
being transcribed: "co-transcriptional splicing." Consistent with
co-transcriptional spliceosome assembly and splicing, we have found significant
enrichment of spliceosomal snRNAs in chromatin-associated RNA compared with
other cellular RNA fractions and other nonspliceosomal snRNAs. CoSI scores
decrease along the gene, pointing to a "first transcribed, first spliced" rule,
yet more downstream exons carry other characteristics, favoring rapid,
co-transcriptional intron removal. Exons with low coSI values, that is, in the
process of being spliced, are enriched with chromatin marks, consistent with a
role for chromatin in splicing during transcription. For alternative exons and
long noncoding RNAs, splicing tends to occur later, and the latter might remain
unspliced in some cases. The human genome contains many thousands of long noncoding RNAs (lncRNAs). While
several studies have demonstrated compelling biological and disease roles for
individual examples, analytical and experimental approaches to investigate these
genes have been hampered by the lack of comprehensive lncRNA annotation. Here,
we present and analyze the most complete human lncRNA annotation to date,
produced by the GENCODE consortium within the framework of the ENCODE project
and comprising 9277 manually annotated genes producing 14,880 transcripts. Our
analyses indicate that lncRNAs are generated through pathways similar to that of
protein-coding genes, with similar histone-modification profiles, splicing
signals, and exon/intron lengths. In contrast to protein-coding genes, however,
lncRNAs display a striking bias toward two-exon transcripts, they are
predomitly localized in the chromatin and nucleus, and a fraction appear to
be preferentially processed into small RNAs. They are under stronger selective
pressure than neutrally evolving sequences-particularly in their promoter
regions, which display levels of selection comparable to protein-coding genes.
Importantly, about one-third seem to have arisen within the primate lineage.
Comprehensive analysis of their expression in multiple human organs and brain
regions shows that lncRNAs are generally lower expressed than protein-coding
genes, and display more tissue-specific expression patterns, with a large
fraction of tissue-specific lncRNAs expressed in the brain. Expression
correlation analysis indicates that lncRNAs show particularly striking positive
correlation with the expression of antisense coding genes. This GENCODE
annotation represents a valuable resource for future studies of lncRNAs. NONCODE (http://www.bioinfo.org/noncode/) is an integrated knowledge database
dedicated to non-coding RNAs (excluding tRNAs and rRNAs). Non-coding RNAs
(ncRNAs) have been implied in diseases and identified to play important roles in
various biological processes. Since NONCODE version 3.0 was released 2 years
ago, discovery of novel ncRNAs has been promoted by high-throughput RNA
sequencing (RNA-Seq). In this update of NONCODE, we expand the ncRNA data set by
collection of newly identified ncRNAs from literature published in the last 2
years and integration of the latest version of RefSeq and Ensembl. Particularly,
the number of long non-coding RNA (lncRNA) has increased sharply from 73 327 to
210 831. Owing to similar alternative splicing pattern to mRNAs, the concept of
lncRNA genes was put forward to help systematic understanding of lncRNAs. The 56
018 and 46 475 lncRNA genes were generated from 95 135 and 67 628 lncRNAs for
human and mouse, respectively. Additionally, we present expression profile of
lncRNA genes by graphs based on public RNA-seq data for human and mouse, as well
as predict functions of these lncRNA genes. The improvements brought to the
database also include an incorporation of an ID conversion tool from RefSeq or
Ensembl ID to NONCODE ID and a service of lncRNA identification. NONCODE is also
accessible through http://www.noncode.org/. |
Is RANKL secreted from the cells? | Receptor activator of nuclear factor κB ligand (RANKL) is a cytokine predominantly secreted by osteoblasts. | Bone destruction is a common feature of inflammatory arthritis and is mediated
by osteoclasts, the only specialized cells to carry out bone resorption.
Aberrant expression of receptor activator of nuclear factor kappa β ligand
(RANKL), an inducer of osteoclast differentiation has been linked with bone
pathology and the synovial fibroblast in rheumatoid arthritis (RA). In this
manuscript, we challenge the current concept that an increase in RANKL
expression governs osteoclastogenesis and bone destruction in autoimmune
arthritis. We isolated human fibroblasts from RA, pyrophosphate arthropathy
(PPA) and osteoarthritis (OA) patients and analyzed their RANKL/OPG expression
profile and the capacity of their secreted factors to induce osteoclastogenesis.
We determined a 10-fold increase of RANKL mRNA and protein in fibroblasts
isolated from RA relative to PPA and OA patients. Peripheral blood mononuclear
cells (PBMC) from healthy volunteers were cultured in the presence of RA, PPA
and OA synovial fibroblast conditioned medium. Osteoclast differentiation was
assessed by expression of tartrate-resistant acid phosphatase (TRAP),
vitronectin receptor (VNR), F-actin ring formation and bone resorption assays.
The formation of TRAP(+), VNR(+) multinucleated cells, capable of F-actin ring
formation and lacunar resorption in synovial fibroblast conditioned medium
cultures occured in the presence of osteoprotegerin (OPG) a RANKL antagonist.
Osteoclasts did not form in these cultures in the absence of macrophage colony
stimulating factor (M-CSF). Our data suggest that the conditioned medium of pure
synovial fibroblast cultures contain inflammatory mediators that can induce
osteoclast formation in human PBMC independently of RANKL. Moreover inhibition
of the TNF or IL-6 pathway was not sufficient to abolish osteoclastogenic
signals derived from arthritic synovial fibroblasts. Collectively, our data
clearly show that alternate osteoclastogenic pathways exist in inflammatory
arthritis and place the synovial fibroblast as a key regulatory cell in bone and
joint destruction, which is a hallmark of autoimmune arthritis. Pulsed electromagnetic field (PEMF) has been shown to increase bone mineral
density in osteoporosis patients and prevent bone loss in ovariectomized rats.
But the mechanisms through which PEMF elicits these favorable biological
responses are still not fully understood. Receptor activator of nuclear factor
κB ligand (RANKL) and osteoprotegerin (OPG) are cytokines predomitly secreted
by osteoblasts and play a central role in differentiation and functional
activation of osteoclasts. The purpose of this study was to investigate the
effects of PEMF on RANKL and OPG expression in ovariectomized rats. Thirty
3-month-old female Sprague-Dawley rats were randomly divided into three groups:
sham-operated control (Sham), ovariectomy control (OVX), and ovariectomy with
PEMF treatment (PEMF). After 12-week interventions, the results showed that PEMF
increased serum 17β-estradiol level, reduced serum tartrate-resistant acid
phosphatase level, increased bone mineral density, and inhibited deterioration
of bone microarchitecture and strength in OVX rats. Furthermore, PEMF could
suppress RANKL expression and improve OPG expression in bone marrow cells of OVX
rats. In conclusion, this study suggests that PEMF can prevent
ovariectomy-induced bone loss through regulating the expression of RANKL and
OPG. Zebrafish scales consist of bone-forming osteoblasts, bone-resorbing
osteoclasts, and calcified bone matrix. To elucidate the underlying molecular
mechanism of the effects induced by dynamic and static acceleration, we
investigated the scale osteoblast- and osteoclast-specific marker gene
expression involving osteoblast-osteoclast communication molecules. Osteoblasts
express RANKL, which binds to the osteoclast surface receptor, RANK, and
stimulates bone resorption. OPG, on the other hand, is secreted by osteoblast as
a decoy receptor for RANKL, prevents RANKL from binding to RANK and thus
prevents bone resorption. Therefore, the RANK-RANKL-OPG pathway contributes to
the regulation of osteoclastogenesis by osteoblasts. Semaphorin 4D, in contrast,
is expressed on osteoclasts, and binding to its receptor Plexin-B1 on
osteoblasts results in suppression of bone formation. In the present study, we
found that both dynamic and static acceleration at 3.0×g decreased RANKL/OPG
ratio and increased osteoblast-specific functional mRNA such as alkaline
phosphatase, while static acceleration increased and dynamic acceleration
decreased osteoclast-specific mRNA such as cathepsin K. Static acceleration
increased semaphorin 4D mRNA expression, while dynamic acceleration had no
effect. The results of the present study indicated that osteoclasts have
predomit control over bone metabolism via semaphorin 4D expression induced by
static acceleration at 3.0×g. Osteoprotegerin (OPG) is a secreted glycoprotein and a member of the tumor
necrosis factor receptor superfamily. It usually functions in bone remodeling,
by inhibiting osteoclastogenesis through interaction with a receptor activator
of the nuclear factor κB (RANKL). Transglutaminases-2 (Tgase-2) is a group of
multifunctional enzymes that plays a role in cancer cell metastasis and bone
formation. However, relationship between OPG and Tgase-2 is not studied.
Therefore, we investigated the involvement of 12-O-Tetradecanoylphorbol
13-acetate in the expression of OPG in MG-63 osteosarcoma cells. Interleukin-1β
time-dependently induced OPG and Tgase-2 expression in cell lysates and media of
the MG-63 cells by a Western blot. Additional 110 kda band was found in the
media of MG-63 cells. 12-O-Tetradecanoylphorbol 13-acetate also induced OPG and
Tgase-2 expression. However, an 110 kda band was not found in TPA-treated media
of MG-63 cells. Cystamine, a Tgase-2 inhibitor, dose-dependently suppressed the
expression of OPG in MG-63 cells. Gene silencing of Tgase-2 also signifi cantly
suppressed the expression of OPG in MG-63 cells. Next, we examined whether a
band of 110 kda of OPG contains an isopeptide bond, an indication of Tgase-2
action, by monoclonal antibody specifi c for the isopeptide bond. However, we
could not fi nd the isopeptide bond at 110 kda but 77 kda, which is believed to
be the band position of Tgase-2. This suggested that 110 kda is not the direct
product of Tgase-2's action. All together, OPG and Tgase-2 is induced by IL-1β
or TPA in MG-63 cells and Tgase-2 is involved in OPG expression in MG-63 cells. BACKGROUND: Resistance to apoptosis is a major problem in ovarian cancer (OC)
and correlates with poor prognosis. Osteoprotegerin (OPG) is a soluble secreted
factor that acts as a decoy receptor for receptor activator of NF-κB ligand
(RANKL) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). OPG
has been reported to attenuate TRAIL-induced apoptosis in a variety of cancer
cells, including OC cells. OPG-mediated protection against TRAIL has been
attributed to its decoy receptor function. However, OPG activates integrin/focal
adhesion kinase (FAK) signaling in endothelial cells. In OC cells, activation of
integrin/FAK signaling inhibits TRAIL-induced apoptosis. Based on these
observations, we hypothesized that OPG could attenuate TRAIL-induced apoptosis
in OC cells through integrin/FAK signaling.
METHODS: In vitro experiments including immunoblots, colony formation assays,
and apoptosis measurements were used to assess the effect of OPG on
TRAIL-induced apoptosis.
RESULTS: Exogenous OPG protected from TRAIL-induced apoptosis in a TRAIL
binding-independent manner and OPG protection was αvβ3 and αvβ5 integrin/FAK
signaling-dependent. Moreover, OPG-mediated activation of integrin/FAK signaling
resulted in the activation of Akt. Inhibition of both integrin/FAK and Akt
signaling significantly inhibited OPG-mediated attenuation of TRAIL-induced
apoptosis. Although OPG also stimulated ERK1/2 phosphorylation, inhibition of
ERK1/2 signaling did not significantly altered OPG protection.
CONCLUSIONS: Our studies provide evidence, for the first time, that OPG can
attenuate TRAIL-induced apoptosis in a TRAIL binding-independent manner through
the activation of integrin/FAK/Akt signaling in OC cells. |
Does metformin interfere thyroxine absorption? | No. There are not reported data indicating that metformin reduce with thyroxine absorption. | |
Which miRNAs could be used as potential biomarkers for epithelial ovarian cancer? | miR-200a, miR-100, miR-141, miR-200b, miR-200c, miR-203, miR-510, miR-509-5p, miR-132, miR-26a, let-7b, miR-145, miR-182, miR-152, miR-148a, let-7a, let-7i, miR-21, miR-92 and miR-93 could be used as potential biomarkers for epithelial ovarian cancer. | OBJECTIVE: To determine the utility of serum miRNAs as biomarkers for epithelial
ovarian cancer.
METHODS: Twenty-eight patients with histologically confirmed epithelial ovarian
cancer were identified from a tissue and serum bank. Serum was collected prior
to definitive therapy. Fifteen unmatched, healthy controls were used for
comparison. Serum was obtained from all patients. RNA was extracted using a
derivation of the single step Trizol method. The RNA from 9 cancer specimens was
compared to 4 normal specimens with real-time PCR using the TaqMan Array Human
MicroRNA panel. Twenty-one miRNAs were differentially expressed between normal
and patient serum. Real-time PCR for the 21 individual miRNAs was performed on
the remaining 19 cancer specimens and 11 normal specimens.
RESULTS: Eight miRNAs of the original twenty-one were identified that were
significantly differentially expressed between cancer and normal specimens using
the comparative C(t) method. MiRNAs-21, 92, 93, 126 and 29a were significantly
over-expressed in the serum from cancer patients compared to controls (p<.01).
MiRNAs-155, 127 and 99b were significantly under-expressed (p<.01).
Additionally, miRs-21, 92 and 93 were over-expressed in 3 patients with normal
pre-operative CA-125.
CONCLUSION: We demonstrate that the extraction of RNA and subsequent
identification of miRNAs from the serum of individuals diagnosed with ovarian
cancer is feasible. Real-time PCR-based microarray is a novel and practical
means to performing high-throughput investigation of serum RNA samples.
miRNAs-21, 92 and 93 are known oncogenes with therapeutic and biomarker
potential. MicroRNAs (miRNA) are approximately 22-nucleotide noncoding RNAs that negatively
regulate protein-coding gene expression in a sequence-specific manner via
translational inhibition or mRNA degradation. Our recent studies showed that
miRNAs exhibit genomic alterations at a high frequency and their expression is
remarkably deregulated in ovarian cancer, strongly suggesting that miRNAs are
involved in the initiation and progression of this disease. In the present
study, we performed miRNA microarray to identify the miRNAs associated with
chemotherapy response in ovarian cancer and found that let-7i expression was
significantly reduced in chemotherapy-resistant patients (n = 69, P = 0.003).
This result was further validated by stem-loop real-time reverse
transcription-PCR (n = 62, P = 0.015). Both loss-of-function (by synthetic
let-7i inhibitor) and gain-of-function (by retroviral overexpression of let-7i)
studies showed that reduced let-7i expression significantly increased the
resistance of ovarian and breast cancer cells to the chemotherapy drug,
cis-platinum. Finally, using miRNA microarray, we found that decreased let-7i
expression was significantly associated with the shorter progression-free
survival of patients with late-stage ovarian cancer (n = 72, P = 0.042). This
finding was further validated in the same sample set by stem-loop real-time
reverse transcription-PCR (n = 62, P = 0.001) and in an independent sample set
by in situ hybridization (n = 53, P = 0.049). Taken together, our results
strongly suggest that let-7i might be used as a therapeutic target to modulate
platinum-based chemotherapy and as a biomarker to predict chemotherapy response
and survival in patients with ovarian cancer. OBJECTIVES: Let-7 is a family of small non-coding RNAs regulating the expression
of many genes that control important cellular activities. Let-7 is shown in
vitro to sensitize cancer cells to platinum, but induce ovarian cancer
resistance to paclitaxel. This study aims to investigate the effect of let-7a
expression on survival outcomes of epithelial ovarian cancer (EOC) patients
treated with different chemotherapy.
METHODS: Let-7a expression was measured with qRT-PCR in ovarian tumors of 178
EOC patients who received platinum-based chemotherapy with and without
paclitaxel after surgery. Survival analysis was performed to assess the effects
of let-7a and chemotherapy on disease outcomes.
RESULTS: Let-7a expression was detectable in the EOC samples, but the expression
was not associated with disease stage, tumor grade, histology and debulking
results. Patients who responded to platinum with paclitaxel had significantly
lower let-7a than those who did not. Survival analyses showed that patients with
high let-7a had better survival compared to those with low let-7a when they were
treated with platinum without paclitaxel. The hazards ratios (HRs) for death and
disease progression were 0.52 (95% CI: 0.29-0.96) and 0.48 (0.26-0.89) for high
let-7a when compared to low let-7a, respectively. However, when patients were
treated with platinum and paclitaxel, high let-7a was associated with worse
progression-free and overall survival. The HRs for death and disease progression
were 3.87 (95% CI: 1.28-11.66) and 3.48 (95% CI: 1.25-9.67) for high let-7a when
compared to low let-7a, respectively. Further studies showed that among patients
with low let-7a, those treated with paclitaxel in addition to platinum survived
better than those treated without paclitaxel [adjusted-HRs were 0.31 (95% CI:
0.15-0.66) for death and 0.40 (95% CI: 0.22-0.75) for disease], while among
those with high let-7a, the two types of treatment made no difference in patient
survival.
CONCLUSIONS: The study suggests that the beneficial impact of the addition of
paclitaxel on EOC survival was significantly linked to let-7a levels, and that
miRNAs such as let-7a may be a useful marker for selection of chemotherapeutic
agents in EOC management. microRNAs (miRs) are endogenous small non-coding RNAs that are aberrantly
expressed in various carcinomas. miR-152 and miR-148a have not been
comprehensively investigated in ovarian cancer. Thus, the aim of this study was
to identify the role of miR-152 and miR-148a in epithelial ovarian cancer. Total
RNA was extracted from tissues of 78 patients with epithelial ovarian cancer, 17
normal ovarian epithelium tissues and two ovarian cancer cell lines. Using
quantitative real-time PCR (qRT-PCR) followed by the 2-ΔΔCT method for
calculating the results, we found that the expression levels of miR-152 were
significantly decreased in ovarian cancer tissues compared to normal ovarian
epithelium tissues (p<0.05). However, although the expression of miR-148a was
also decreased in 65% of patients, no statistically significant difference in
expression was found. A strong correlation was found between the expression of
miR-152 and miR-148a (p<0.001, Pearson's correlation). The relationship between
miR-152 or miR-148a expression levels in ovarian cancer and clinicopathological
features, response to therapy and short-term survival was analyzed and the
results showed that no correlation existed. In addition, we found that both
miR-152 and miR-148a were down-regulated in ovarian cancer cell lines. After
miR-152 or miR-148a mimics were transfected into ovarian cancer cell lines, the
MTT cell proliferation assay showed that cell proliferation was significantly
inhibited. Taken together, miR-152 and miR-148a may be involved in the
carcinogenesis of ovarian cancer through deregulation of cell proliferation.
They may be novel biomarkers for early detection or therapeutic targets of
ovarian cancer. BACKGROUND: There is a critical need for improved diagnostic markers for high
grade serous epithelial ovarian cancer (SEOC). MicroRNAs are stable in the
circulation and may have utility as biomarkers of maligcy. We investigated
whether levels of serum microRNA could discriminate women with high-grade SEOC
from age matched healthy volunteers.
METHODS: To identify microRNA of interest, microRNA expression profiling was
performed on 4 SEOC cell lines and normal human ovarian surface epithelial
cells. Total RNA was extracted from 500 μL aliquots of serum collected from
patients with SEOC (n = 28) and age-matched healthy donors (n = 28). Serum
microRNA levels were assessed by quantitative RT-PCR following preamplification.
RESULTS: microRNA (miR)-182, miR-200a, miR-200b and miR-200c were highly
overexpressed in the SEOC cell lines relative to normal human ovarian surface
epithelial cells and were assessed in RNA extracted from serum as candidate
biomarkers. miR-103, miR-92a and miR -638 had relatively invariant expression
across all ovarian cell lines, and with small-nucleolar C/D box 48 (RNU48) were
assessed in RNA extracted from serum as candidate endogenous normalizers. No
correlation between serum levels and age were observed (age range 30-79 years)
for any of these microRNA or RNU48. Individually, miR-200a, miR-200b and
miR-200c normalized to serum volume and miR-103 were significantly higher in
serum of the SEOC cohort (P < 0.05; 0.05; 0.0005 respectively) and in
combination, miR-200b + miR-200c normalized to serum volume and miR-103 was the
best predictive classifier of SEOC (ROC-AUC = 0.784). This predictive model
(miR-200b + miR-200c) was further confirmed by leave one out cross validation
(AUC = 0.784).
CONCLUSIONS: We identified serum microRNAs able to discriminate patients with
high grade SEOC from age-matched healthy controls. The addition of these
microRNAs to current testing regimes may improve diagnosis for women with SEOC. OBJECTIVE: MicroRNA (miRNA) is an abundant class of small noncoding RNAs that
act as gene regulators. Recent studies have suggested that miRNA deregulation is
associated with the initiation and progression of human cancer. However,
information about cancer-related miRNA is mostly limited to tissue miRNA. The
aim of this study was to find specific profiles of serum-derived miRNAs of
ovarian cancer based on a comparative study using a miRNA microarray of serum,
tissue, and ascites.
METHODS: From 2 ovarian cancer patients and a healthy control, total RNA was
isolated from their serum, tissue, and ascites, respectively, and analyzed by a
microarray. Under the comparative study of each miRNA microarray, we sorted out
several miRNAs showing a consistent regulation tendency throughout all 3
specimens and the greatest range of alteration in serum as potential biomarkers.
The availability of biomarkers was confirmed by qRT-PCR of 18 patients and 12
controls.
RESULTS: Out of 2222 kinds of total miRNAs that were identified in the
microarray analysis, 95 miRNAs were down-regulated and 88 miRNAs were
up-regulated, in the serum, tissue, and ascites of cancer patients. Among the
miRNAs that showed a consistent regulation tendency through all specimens and
showed more than a 2-fold difference in serum, 5 miRNAs (miR-132, miR-26a,
let-7b, miR-145, and miR-143) were determined as the 5 most markedly
down-regulated miRNAs in the serum from ovarian cancer patients with respect to
those of controls. Four miRNAs (miR-132, miR-26a, let-7b, and miR-145) out of 5
selected miRNAs were significantly underexpressed in the serum of ovarian cancer
patients in qRT-PCR.
CONCLUSIONS: Serum miR-132, miR-26a, let-7b, and miR-145 could be considered as
potential candidates as novel biomarkers in serous ovarian cancer. Also, serum
miRNAs is a promising and useful tool for discriminating between controls and
patients with serous ovarian cancer. Recent investigations have confirmed up-regulation of serum miR-21 and its
diagnostic and prognostic value in several human maligcies. In this study, we
examined serum miR-21 levels in epithelial ovarian cancer (EOC) patients, and
explored its association with clinicopathological factors and prognosis. The
results showed significantly higher serum miR-21 levels in EOC patients than in
healthy controls. In addition, increased serum miR-21 expression was correlated
with advanced FIGO stage, high tumor grade, and shortened overall survival.
These findings indicate that serum miR-21 may serve as a novel diagnostic and
prognostic marker, and be used as a therapeutic target for the treatment of EOC. Epithelial ovarian cancer (EOC) is the leading cause of death among gynecologic
maligcies. Despite great efforts to improve early detection and optimize
chemotherapeutic regimens, the 5-year survival rate is only 30% for patients
presenting with late-stage ovarian cancer. The high mortality of this disease is
due to late diagnosis in over 70% of ovarian cancer cases. A class of small
noncoding RNAs, or microRNAs, was found to regulate gene expression at the
post-transcriptional level. Some, but not all, of the data indicated that the
miR-200 family was dysregulated in a variety of maligcies. In this study, we
demonstrated that miR-200a and E-cadherin were significantly upregulated in EOC
compared to benign epithelial ovarian cysts and normal ovarian tissues. However,
further stratification of the subject indicated that the expression levels of
miR-200a were significantly downregulated in late-stage (FIGO III+V) and grade 3
groups compared with early stage (FIGO I+II) and grade 1 to 2 groups. Similarly,
relatively low levels of miR-200a were observed in the lymph compared to the
node-negative group. E-cadherin expression was found to be absent in normal
ovarian tissue and was frequently expressed in benign epithelial ovarian cysts,
with absence or low levels observed in late-stage ovarian cancers. There was a
significantly positive correlation between miR-200a and E-cadherin in EOC. The
biphasic expression pattern suggested that miR-200a levels may serve as novel
biomarkers for the early detection of EOC, and miR-200a and E-cadherin are
candidate targets for the development of new treatment modalities against
ovarian cancer. MicroRNA-203 (miR-203), possessing tumor suppressive or promotive activities,
has been found to be downregulated or upregulated in different cancer types. The
purpose of this study was to investigate whether the increased expression of
miR-203 can be used as a noninvasive diagnostic and prognostic biomarker in
epithelial ovarian cancer (EOC). Real-time quantitative PCR was performed to
detect the expression levels of miR-203 in EOC tissues. The expression levels of
miR-203 were significantly higher in EOC tissues compared to adjacent
non-cancerous tissues (p < 0.001). High expression of miR-203 was observed in
65.38 % (102/156) of EOC. In addition, high miR-203 expression was found to be
closely correlated with advanced FIGO stage (p < 0.001), higher histological
grade (p = 0.02), lymph node involvement (p < 0.001), and positive recurrence
(p < 0.001). Moreover, high miR-203 expression was correlated with shorter
overall survival (p < 0.001) and shorter progression-free survival (p < 0.001)
of EOC patients. Furthermore, multivariate analysis showed that the status of
miR-203 expression was an independent predictor for both overall survival and
progression-free survival in EOC. These findings provide the convincing evidence
for the first time that the upregulation of miR-203 may serve as a novel
molecular marker to predict the aggressive tumor progression and unfavorable
prognosis of EOC patients. |
Which acetylcholinesterase inhibitors are used for treatment of myasthenia gravis? | Pyridostigmine and neostygmine are acetylcholinesterase inhibitors that are used as first-line therapy for symptomatic treatment of myasthenia gravis. Pyridostigmine is the most widely used acetylcholinesterase inhibitor. Extended release pyridotsygmine and novel acetylcholinesterase inhibitors inhibitors with oral antisense oligonucleotides are being studied. | Treatment for myasthenia gravis should be individualized to each patient based
on the clinical characteristics of myasthenia including the distribution,
duration, and severity of weakness and resulting functional impairment; the
risks for treatment complications related to age, gender, and medical
comorbidities; and the presence of thymoma. Acetylcholinesterase inhibitors
provide temporary, symptomatic treatment for all forms of myasthenia gravis.
Immune modulators address the underlying autoimmune process in myasthenia
gravis, but are associated with potential complications and side effects. Most
patients with generalized myasthenia who have significant weakness beyond the
ocular muscles and who remain symptomatic, despite treatment with cholinesterase
inhibitors, are candidates for immune modulation. Although corticosteroids are
effective for long-term immune modulation in myasthenia gravis, several more
contemporary immunomodulators including azathioprine, cyclosporine, and
mycophenolate mofetil have shown efficacy in myasthenia gravis and are used
increasingly as first-line treatments and as steroid-sparing agents. Plasma
exchange is used to achieve rapid improvement in patients with myasthenic crisis
or exacerbation, to improve strength before a surgical procedure or thymectomy,
and to minimize steroid-induced exacerbation in patients with oropharyngeal or
respiratory muscle weakness. Intravenous immunoglobulin represents an
alternative to plasma exchange in patients requiring relatively rapid short-term
improvement in the setting of poor venous access. Because of a lack of
controlled trials, the role of thymectomy in nonthymomatous myasthenia gravis is
unclear, although evidence suggests that thymectomy increases the probability
for myasthenic remission or improvement. INTRODUCTION: For more than 50 years the acetylcholinesterase inhibitor
pyridostigmine bromide has been the drug of choice in the symptomatic therapy
for myasthenia gravis. The sustained-release dosage form of pyridostigmine
(SR-Pyr) is only available in a limited number of countries (e.g. in the United
States and Germany). Astonishingly, the therapeutic usefulness of SR-Pyr has not
yet been evaluated.
METHODS: In this non-interventional prospective open-label trial, 72 patients
with stable myasthenia gravis were switched from instant-release dosage forms of
pyridostigmine bromide to SR-Pyr. The results from the 37 patients younger than
60 years were separately analyzed.
RESULTS: The initial daily dose of SR-Pyr was 288.1 ± 171.0mg. The drug switch
was unproblematic in all patients. The number of daily doses was significantly
reduced from 4.3 to 3.6 (p=0.011). The switch to SR-Pyr ameliorated the total
quantified myasthenia gravis (QMG) score from 0.9 ± 0.5 to 0.6 ± 0.4 (p<0.001)
in all patients and in the younger subgroup. This was accompanied by a
significant improvement in the quality of life parameters. The health status
valued by EuroQoL questionnaire improved from 0.626 ± 0.286 to 0.782 ± 0.186
(p<0.001). After switching to SR-Pyr, 28 adverse reactions disappeared and 24
adverse reactions occurred less frequent or weaker, however, 17 new adverse
reactions were documented.
CONCLUSIONS: Our results support the usefulness of SR-Pyr in an individualized
therapeutic regimen to improve quality of life regardless of the patient's age
in myasthenia gravis. Myasthenia gravis (MG) is caused by failure of chemical transmission at the
neuromuscular junction. It is an autoimmune disorder in which antibodies
interfere with neuromuscular transmission. It has a prevalence of around 20 per
100,000. The incidence is bimodal with a 2:1 female to male ratio in the younger
population and a reversed sex ratio over the age of 60. Around 15% of cases are
associated with a thymoma. MG presents with fatiguable painless muscle weakness.
Diplopia and ptosis are the most common presenting features. Around 80% of
patients presenting with ocular MG will subsequently develop more generalised
weakness. Respiratory muscle weakness is the most serious manifestation of MG
and can be fatal. A detailed history is the most valuable tool in the diagnosis
of MG. This should elicit the pattern of weakness, severity and diurnal
variation. Exacerbating factors including extremes of weather, emotional stress,
menstruation and intercurrent illness should be enquired about. No one
diagnostic test is 100% sensitive and patients who have negative antibodies and
normal neurophysiology may still have MG. Treatment should be directed at
ameliorating weakness with acetylcholinesterase blockers and modulating the
immune system. Pyridostigmine is the most widely used acetylcholinesterase
inhibitor. Most patients with generalised MG require immunomodulatory therapy
and prednisolone is generally used as the first-line agent. Despite the
availability of symptomatic and immunomodulatory treatment, up to 20% of
patients will experience a myasthenic crisis requiring admission for ventilatory
support at some stage. Acquired myasthenia gravis (MG) is a chronic autoimmune disorder of the
neuromuscular junction, characterized clinically by muscle weakness and abnormal
fatigability on exertion. Current guidelines and recommendations for MG
treatment are based largely on clinical experience, retrospective analyses and
expert consensus. Available therapies include oral acetylcholinesterase (AChE)
inhibitors for symptomatic treatment, and short- and long-term disease-modifying
treatments. This review focuses on treatment of MG, mainly on the use of the
AChE inhibitor pyridostigmine. Despite a lack of data from well controlled
clinical trials to support their use, AChE inhibitors, of which pyridostigmine
is the most commonly used, are recommended as first-line therapy for MG.
Pyridostigmine has been used as a treatment for MG for over 50 years and is
generally considered safe. It is suitable as a long-term treatment in patients
with generalized non-progressive milder disease, and as an adjunctive therapy in
patients with severe disease who are also receiving immunotherapy. Novel AChE
inhibitors with oral antisense oligonucleotides have been developed and
preliminary results appear to be promising. In general, however, AChE inhibitors
provide only partial benefit and most patients eventually switch to long-term
immunosuppressive therapies, most frequently corticosteroids and/or
azathioprine. Although AChE inhibitors are known to be well tolerated and
effective in relieving the symptoms of MG, further efforts are required to
improve treatment options for the management of this disorder. Myasthenia gravis is an autoimmune neuromuscular disorder. There are several
treatment options, including symptomatic treatment (acetylcholinesterase
inhibitors), short-term immunosuppression (corticosteroids), long-term
immunosuppression (azathioprine, cyclosporine, cyclophosphamide, methotrexate,
mycophenolate mofetil, rituximab, tacrolimus), rapid acting short-term
immunomodulation (intravenous immunoglobulin, plasma exchange), and long-term
immunomodulation (thymectomy). This review explores in detail these different
treatment options. Potential future treatments are also discussed. |
Has Denosumab (Prolia) been approved by FDA? | Yes, Denosumab was approved by the FDA in 2010. | Osteoporosis in men is finally receiving some attention; it has been realized
that men are more likely to die after hip fracture. Methods for screening men
for osteoporosis include dual energy x-ray absorptiometry and use of fracture
risk calculators such as FRAX (World Health Organization) and the Garvan
nomogram. Evaluation of men will often identify secondary causes of osteoporosis
as well as multiple risk factors. Alendronate, risedronate, zoledronic acid, and
teriparatide are US Food and Drug Administration (FDA)--approved therapy for
men. Men on androgen deprivation therapy (ADT) are at high risk for bone loss
and fracture, and all the bisphosphonates have been shown to increase bone
density. The new antiresorptive drug, denosumab, although FDA-approved only for
postmenopausal women, has been shown in a study of men on ADT to increase bone
density in spine, hip, and forearm and decrease vertebral fractures on x-ray.
Thus, there is great progress in osteoporosis in men, and recognition of its
importance is increasing. Osteoporosis is a common consequence of androgen deprivation therapy (ADT) for
prostate cancer. Up to 20% of men on ADT for localized prostate cancer will
fracture within 5 years. Fortunately, generally safe and effect therapy is
available. Although once considered non-controversial, there is some concern
about calcium supplementation, but all studies of osteoporosis therapy in men
have included calcium. In most older men, serum 25-hydroxyvitamin D levels are
likely to be low, although again there is controversy about the ideal level.
Many experts believe that all older men, including those on ADT, need to have a
level of >30 ng/ml, which is easily accomplished. Bone mineral density (BMD)
testing by dual energy X-ray absorptiometry (DXA) is indicated for men on ADT.
Interestingly, forearm DXA may be particularly important in ADT men, in addition
to spine and hip. Some experts have suggested that men on ADT with a T-score of
≤-1.5 should be treated. Alternatively FRAX or another risk calculator can be
used. Oral and intravenous bisphosphonates are FDA approved treatments for men
with osteoporosis and increase BMD in men on ADT. Potential off-label agents
include raloxifene and toremifene. The latter and denosumab have been shown to
increase bone density and decrease vertebral fractures in men on ADT. Raloxifene
and denosumab are only FDA approved for postmenopausal osteoporosis. Thus,
prevention of fractures can be accomplished in this high risk population. The Austrian Society for Bone and Mineral Research routinely publishes
evidence-based guidelines for the treatment of postmenopausal osteoporosis. The
fully human monoclonal antibody denosumab (Prolia(®)) has been recently approved
by the European Medical Agency (EMEA) and the Food and Drug Administration (FDA)
for the treatment of postmenopausal osteoporosis. Denosumab has been shown to
reduce vertebral, non-vertebral,and hip-fracture risk effectively. Together with
alendronate, risedronate, zoledronate, ibandronate, strontium ranelate, and
raloxifene, denosumab constitutes an effective option in the treatment of
postmenopausal osteoporosis. Therapeutic antibodies have captured substantial attention due to the relatively
high rate at which these products reach marketing approval, and the subsequent
commercial success they frequently achieve. In the 2000s, a total of 20
antibodies (18 full-length IgG and 2 Fab) were approved by the Food and Drug
Administration (FDA) or European Medicines Agency (EMA). In the 2010s to date,
an additional 3 antibodies (denosumab, belimumab, ipilimumab) have been approved
and one antibody-drug conjugate (brentuximab vedotin) is undergoing regulatory
review and may be approved in the US by August 30, 2011. However, a less
heralded group of antibody-based therapeutics comprising proteins or peptides
fused with an Fc is following the success of classical antibodies. BACKGROUND: Bone metastases are common in patients with hormone-refractory
prostate cancer. In a study of autopsies of patients with prostate cancer,
65%-75% had bone metastases. Bone metastases place a substantial economic burden
on payers with estimated total annual costs of $1.9 billion in the United
States. Skeletal-related events (SREs), including pathologic fractures, spinal
cord compression, surgery to bone, and radiation to bone, affect approximately
50% of patients with bone metastases. They are associated with a decreased
quality of life and increased health care costs. Zoledronic acid is an effective
treatment in preventing SREs in solid tumors and multiple myeloma. Recently,
denosumab was FDA-approved for prevention of SREs in patients with bone
metastases from solid tumors. A Phase 3 clinical trial (NCT00321620)
demonstrated that denosumab had superior efficacy in delaying first and
subsequent SREs compared with zoledronic acid. However, the economic value of
denosumab has not been assessed in patients with hormone-refractory prostate
cancer.
OBJECTIVE: To compare the cost-effectiveness of denosumab with zoledronic acid
in the treatment of bone metastases in men with hormone-refractory prostate
cancer.
METHODS: An Excel-based Markov model was developed to assess costs and
effectiveness associated with the 2 treatments over a 1- and 3-year time
horizon. Because the evaluation was conducted from the perspective of a U.S.
third-party payer, only direct costs were included. Consistent with the primary
outcome in the Phase 3 trial, effectiveness was assessed based on the number of
SREs. The model consisted of 9 health states defined by SRE occurrence, SRE
history, disease progression, and death. A hypothetical cohort of patients with
hormone-refractory prostate cancer received either denosumab 120 mg or
zoledronic acid 4 mg at the model entry and transitioned among the 9 health
states at the beginning of each 13-week cycle. Transition probabilities
associated with experiencing the first SRE, subsequent SREs, disease
progression, and death were primarily derived from the results of the Phase 3
clinical trial and were supplemented with published literature. The model
assumed that a maximum of 1 SRE could occur in each cycle. Drug costs included
wholesale acquisition cost, health care professional costs associated with drug
administration, and drug monitoring costs, if applicable. Nondrug costs included
incremental costs associated with disease progression, costs associated with
SREs, and terminal care costs, which were derived from the literature. Adverse
event (AE) costs were estimated based on the incidence rates reported in the
Phase 3 trial. Resource utilization associated with AEs was estimated based on
consultation with a senior medical director employed by the study sponsor. All
costs were presented in 2010 dollars. The base case estimated the incremental
total cost per SRE avoided over a 1-year time horizon. Results for a 3-year time
horizon were also estimated. One-way sensitivity analyses and probabilistic
sensitivity analyses (PSA) were performed to test the robustness of the model.
RESULTS: In the base case, the total per patient costs incurred over 1 year were
estimated at $35,341 ($19,230 drug costs and $16,111 nondrug costs) for
denosumab and $27,528 ($10,960 drug costs and $16,569 nondrug costs) for
zoledronic acid, with an incremental total direct cost of $7,813 for denosumab.
The estimated numbers of SREs per patient during the 1-year period were 0.49 for
denosumab and 0.60 for zoledronic acid, resulting in an incremental number of
SREs of -0.11 in the denosumab arm. The estimated incremental total direct costs
per SRE avoided with the use of denosumab instead of zoledronic acid were
$71,027 for 1 year and $51,319 for 3 years. The 1-way sensitivity analysis
indicated that the results were sensitive to the drug costs, median time to
first SRE, and increased risk of SRE associated with disease progression.
Results of the PSA showed that based on willingness-to-pay thresholds of
$70,000, $50,000, and $30,000 per SRE avoided, respectively, denosumab was
cost-effective compared with zoledronic acid in 49.5%, 17.5%, and 0.3% of the
cases at 1 year, respectively, and 79.0%, 49.8%, and 4.1% of the cases at 3
years, respectively.
CONCLUSIONS: Although denosumab has demonstrated benefits over zoledronic acid
in preventing or delaying SREs in a Phase 3 trial, it may be a costly
alternative to zoledronic acid from a U.S. payer perspective. Most men with recurrent prostate cancer (CaP) initially respond to androgen
deprivation therapy but eventually develop metastatic castration-resistant
prostate cancer (CRPC). Over the last decade, new therapeutic targets have been
identified in CRPC and several new drugs have reached advanced stages of
clinical development. In 2010, the Food and Drug Administration (FDA) approved
sipuleucel-T and cabazitaxel, and in 2011, abiraterone for patients with
metastatic CRPC based on phase 3 trials showing improved survival. Although not
yet available for clinical use, a press release in June 2011 announced that
radium 223 also demonstrated a survival advantage in men with metastatic CRPC.
Emerging therapies in advanced stages of clinical development in CRPC include
the hormonal therapies MDV3100 and TAK 700, and the immunotherapy ipilimumab.
Results are also pending on phase 3 studies comparing docetaxel plus prednisone
with docetaxel given with the novel agents aflibercept, dasatinib, lenalidomide,
and custirsen. In addition to these new and emerging therapeutic agents,
denosumab was approved for the prevention of skeletal complications in patients
with bone metastases due to solid tumor maligcies, providing an alternative
to zoledronic acid. While the addition of these new treatment options is a great
advance for men with metastatic CRPC, there are many new questions arising
regarding sequencing of these treatments with each other, with previously
existing therapies, and with the emerging agents now in clinical trials.
Furthermore, there are concerns that on-going phase 3 trials may be contaminated
if patients go off study treatment to start 1 of the newly approved agents or
take the agent subsequently. These realities make clinical trial design more
challenging than ever. BACKGROUND: In 2007, the Agency for Healthcare Research and Quality(AHRQ)
published a systematic review on the comparative effectiveness of treatments for
osteoporosis. The review included studies on the benefits and risks of
medications and therapies used to prevent fractures in postmenopausal women and
men with low bone density (osteopenia) or osteoporosis. Factors that may affect
adherence to treatment, and monitoring for the identification of those most
likely to benefit from treatment were also included in this review. AHRQ
published an updated review in March 2012 that summarized the benefits and risks
of osteoporosis medications in treatment and prevention of osteoporosis,
including bisphosphonates (aledronate, risedronate, ibandronate, zoledronic
acid), parathyroid hormone, teriparatide, calcitonin, estrogens (for prevention
in postmenopausal women), selective estrogen receptor modulators (raloxifene),
and denosumab(approved by the FDA in 2010). In addition, dietary and
supplemental calcium and vitamin D, as well as weight-bearing exercise, for the
preservation of bone mass and the decrease of fracture risk in patients with
osteoporosis, were evaluated.
OBJECTIVES: To (a) familiarize health care professionals with the methods and
findings from AHRQ's 2012 comparative effectiveness review on treatments to
prevent fractures in men and women with low bone density or osteoporosis, (b)
encourage consideration and application of the findings of this review in
clinical and managed care settings, and (c) identify limitations and gaps in the
existing research with respect to the benefits and risks of treatments for
osteoporosis.
SUMMARY: Osteoporosis is a prevalent systemic skeletal disease caused by bone
deterioration and loss of mass resulting in fractures, chronic pain and physical
disability. It is common in postmenopausal women but men are at risk as well for
fractures associated with low bone density. The increasing prevalence and cost
of treating osteoporosis make the study of safety and effectiveness for
currently available osteoporosis therapies pertinent and timely. In 2012, the
Agency for Healthcare Research and Quality (AHRQ) published an updated review on
the effectiveness and safety of treatments for osteoporosis, including new
therapies for the prevention of vertebral and nonvertebral fractures in
postmenopausal women and men.The interventions assessed in the review included 1
biological agent, pharmacological agents, dietary and supplemental calcium and
vitamin D, and weight-bearing exercise. The updated report included the new
agents and indications approved after the 2007 report and new data on
effectiveness and adverse events associated with the bisphosponates; calcitonin
was determined by the reviewers to not be appropriate therapy for osteoporosis
and was excluded. The updated review examined 5 key questions focused on
comparative review of all FDA-approved medicines for osteoporosis in fracture
risk reduction, effectiveness in racial/ethnic subpopulations as well as
different risk stratification using FRAX (World Health Organization Fracture
Risk Assessment Tool) or other cutoffs, compliance and adherence, adverse
effects of medications, the prediction of treatment efficacy using bone mineral
density (BMD) monitoring by dual energy x-ray absorptiometry (DXA), and
comparative effectiveness of long-term therapy.The AHRQ reviewers found high
strength of evidence to support a reduction in risk of vertebral, nonvertebral
and hip fractures in postmenopausal women with osteoporosis treated with 1 of 4
agents (alendronate, risedronate, zoledronic acid, or denosumab). A risk
reduction for vertebral fractures in postmenopausal women with osteoporosis
treated with ibandronate, teriparatide, or raloxifene therapy was supported with
high-strength evidence. Evidence was graded high strength for reduction of
vertebral and hip fracture with estrogen therapy in postmenopausal women but not
in women with established osteoporosis. Evidence was graded moderate for a
reduction in nonvertebral fractures with teriparatide or calcium monotherapy.
Moderate or low-moderate strength of evidence showed that calcium alone does not
reduce the risk of vertebral or nonvertebral fracture, and that vitamin D has
mixed results on decreasing overall fracture risk. High-strength evidence
supports a reduction in the risk of hip fracture with calcium treatment. Vitamin
D treatment significantly reduced vertebral fractures among patients with
primary osteoporosis. The combination of calcium plus vitamin C did not reduce
vertebral fracture risk, but did reduce nonvertebral fracture risk in certain
populations. Calcium plus vitamin D did decrease the risk of fracture in elderly
women but not in elderly men. Adherence and persistence to osteoporosis
medications varied depending on patient age, prior history of fracture, dosing
frequency, concomitant use of other medications, and adverse effects. Adherence
to treatment improved with weekly dosing compared with daily regimens, but
evidence was lacking to show monthly regimens improved adherence over weekly
regimens. This article recaps the key findings from the AHRQ 2012 review for the
purpose of informing health care providers about the efficacy and safety of
therapies used to prevent osteoporotic vertebral, nonvertebral, hip, and wrist
fractures. Scientific literature on the effects of risk factors, adherence, BMD
monitoring, and long-term therapy on patient outcomes is reviewed in order to
inform prescribing decisions. In addition, applications of the AHRQ findings to
practice are discussed to provide clinicians with information needed to provide
evidence-based care for their patients. Prostate cancer (PC) is the leading cause of cancer and the second leading cause
of cancer-death among men in the Western world. About 10-20% of men with PC
present with metastatic disease at diagnosis, while 20-30% of patients diagnosed
with localized disease will eventually develop metastases. Although most respond
to initial androgen-deprivation therapy (ADT), progression to
castration-resistant PC (CRPC) is universal. In 2004 the docetaxel/prednisone
regimen was approved for the management of patients with metastatic CRPC,
becoming the standard first-line therapy. Recent advances have now led to an
unprecedented number of new drug approvals within the past years, providing many
new treatment options for patients with metastatic CRPC. Four new drugs have
received U.S. Food and Drug Administration (FDA)-approval in 2010 and 2011:
sipuleucel-T, an immunotherapeutic agent; cabazitaxel, a novel microtubule
inhibitor; abiraterone acetate, a new androgen biosynthesis inhibitor; and
denosumab, a bone-targeting agent. The data supporting the approval of each of
these agents are described in this review, as are current approaches in the
treatment of metastatic CRPC and ongoing clinical trials of novel treatments and
strategies. Prostate cancer is the second leading cause of cancer death in men in the
western world. Most deaths will occur due to the progression of cancer into a
hormone refractory state. Until recently, docetaxel-based chemotherapy was the
only established treatment (shown to increase survival) for patients with
metastatic hormone refractory prostate cancer. The improved understanding of
prostate cancer biology in recent years led to the development of drugs directed
against precise tumorigenesis-associated molecular pathways, and significant
expansion of treatment horizons for these patients. In 2010-2011, three more
agents, with different mechanisms of action, were shown to be associated with a
survival benefit in mHRPC, including the dendritic cell vaccine sipuleucel-T
(immunotherapy), the 17,20 lyase inhibitor abiraterone (hormonal therapy), and
the taxane cabazitaxel (chemotherapy). A fourth agent, denosumab (bone targeted
therapy) was also recently approved by the FDA for patients with bone metastasis
after showing a reduction in the occurrence of skeletal-related events. This
review will focus on recent advances in the standard treatments paradigm in
mHRPC. Worldwide over 12 million people were diagnosed with cancer (excluding
non-melanoma skin cancer) and 8 million individuals died from cancer in 2008.
Recent data indicate that 75-90% of patients with advanced stage diseases or
metastatic cancer will experience significant cancer pain. Bone cancer pain is
common in patients with advanced breast, prostate, and lung cancer as these
tumors have a marked affinity to metastasize to bone. Once tumors metastasize to
bone, they are a major cause of morbidity and mortality as the tumor induces
significant skeletal remodeling, fractures, pain and anemia; all of which reduce
the functional status, quality of life and survival of the patient. Currently,
the factors that drive cancer pain are poorly understood, however, several
recently introduced models of bone cancer pain that mirror the human condition,
are providing insight into the mechanisms that drive bone cancer pain and
guiding the development of novel therapies to treat the cancer pain. Several of
these therapies have recently been approved by the FDA to treat bone cancer pain
(bisphosphonates, denosumab) and others are currently being evaluated in human
clinical trials (tanezumab). These new mechanism-based therapies are enlarging
the repertoire of modalities available to treat bone cancer pain and improving
the quality of life and functional status of patients with bone cancer. OBJECTIVE: To review information pertinent to bone health and osteoporosis in
men.
METHODS: A review of pertinent literature was conducted.
RESULTS: Osteoporosis affects approximately 2 million men in the US and accounts
for an estimated 600,000 fractures each year. There are significant differences
in skeletal size and structure between men and women that account for
differences in fracture incidence, location, and outcomes. Bone density testing
is appropriate for men age 70 and older and younger men (50-69) who have risk
factors for osteoporosis. Lifestyle management, including adequate calcium and
vitamin D intake, appropriate physical activity, and avoidance of tobacco and
heavy alcohol use, is appropriate for all men. Pharmacologic therapy to reduce
fracture risk is advisable for men with a clinical diagnosis of osteoporosis (a
spine or hip fracture) or a T-score of -2.5 or below in the spine, femoral neck,
total hip or 1/3 radius; however, the majority of men at high risk will only be
identified using a fracture risk assessment tool, such as FRAX. Alendronate,
risedronate, zoledronic acid, denosumab, and teriparatide are Food and Drug
Administration (FDA)-approved therapeutic options.
CONCLUSIONS: Osteoporosis in men presents an important public health problem
with significant morbidity and mortality. There are recommended strategies for
identifying men at high risk of fracture, and effective agents are available for
treatment. In women with advanced breast cancer, approximately three-quarters develop
metastases to the bone, with a median survival after diagnosis of 2-3 years.
Receptor activator of nuclear factor-κB (RANK) and RANK ligand (RANKL) belong to
a signal pathway highly implicated in the development of bone metastases.
Denosumab, a human monoclonal antibody with high affinity and specificity for
RANKL, prevents the RANKL/RANK interaction and inhibits osteoclast formation and
function, thereby decreasing bone resorption and increasing bone mass. Denosumab
compared with zoledronic acid showed superior efficacy in delaying time to
first-on study SRE and time to first- and subsequent-on study SREs as well as
reduction in bone turnover markers. These results led to the approval of
denosumab by the European Medicines Agency (EMA) and the US Food and Drug
Administration (FDA), for the prevention of SREs in adults with bone metastases
from solid tumors, including breast cancer. Postmenopausal osteoporosis is a major concern to public health. Fractures are
the major clinical consequence of osteoporosis and are associated with
substantial morbidity, mortality and health care costs. Bone strength
determits such as bone mineral density and bone quality parameters are
determined by life-long remodeling of skeletal tissue. Receptor activator of
nuclear factor-kB ligand (RANKL) is a cytokine essential for osteoclast
differentiation, activation and survival. Denosumab (Prolia®) is a fully human
monoclonal antibody for RANKL, which selectively inhibits osteoclastogenesis,
being recently approved for the treatment of postmenopausal osteoporosis in
women at a high or increased risk of fracture by the FDA in the United States
and by the European Medicines Agency in Europe since June 2010. FREEDOM, DECIDE
and STAND are the phase 3 trials comparing denosumab with placebo and
alendronate in postmenopausal osteoporosis. The authors aim to update denosumab
role in postmenopausal osteoporosis with a physiopathological review. Giant cell tumor of bone (GCTB) is an osteolytic, usually benign neoplasm
characterized by infiltration with osteoclast-like giant cells, and the
osteoclast differentiation factor receptor activator of nuclear factor kappa-B
ligand (RANKL) is heavily involved in its pathogenesis. Denosumab belongs to a
new class of drugs that inhibit RANKL. Prior to denosumab, multimodality
treatment in refractory, recurrent and metastatic GCTB has shown variable
results. Recent phase II data have demonstrated denosumab's activity with regard
to disease and symptom control, without significant adverse effects. On the
basis of this data, the FDA approved denosumab for the treatment of patients
whose GCTB is unresectable, or when surgery is likely to result in severe
morbidity. Ongoing questions remain, including the optimal scheduling, patient
selection, use in the adjuvant setting and long-term toxicity concerns. BACKGROUND CONTEXT: Denosumab (XGeva) is a receptor activator of nuclear
factor-κB ligand (RANKL)-antibody that was approved by the Food and Drug
Administration (FDA) in 2010 for the prevention of skeletal fractures in
patients with bone metastases from solid tumors. Although there is a widespread
use of such drug in patients under risk of pathological fractures, the
compatibility of denosumab therapy with percutaneous vertebroplasty (an
interventional procedure commonly used for pain control in such population) has
not yet been established.
PURPOSE: To present the serial imaging findings and technical report of an
attempted percutaneous vertebroplasty in a patient with refractory pain and a
lytic pathological vertebral fracture related to small cell lung cancer spinal
metastasis and who was actively under medical treatment with denosumab.
STUDY DESIGN: Retrospective review and case report.
METHODS: The authors present the imaging findings and technical report of an
attempted percutaneous vertebroplasty in the only patient found to be actively
under treatment with denosumab after a retrospective review of the databank of
patients with pathological fractures referred to the Department of Radiology of
the Ohio State University for percutaneous vertebroplasty (a total sample of 20
patients) since the FDA approval of denosumab (November 2010) until June 2013 (a
30-month period).
RESULTS: Although the computed tomography scan of the thoracic spine, performed
6 weeks after the initiation of the treatment with denosumab, presented a
remarkable remodeling of the previously lytic vertebral lesion (which became
markedly sclerotic in appearance), the clinical response in terms of pain
improvement was not satisfactory. At the time of the percutaneous vertebroplasty
(which was indicated for pain control), after advancing the 11-gauge needle
through the pedicle with extreme difficulty, the needle repeatedly deviated
laterally and, despite several attempts, it was not possible to penetrate the
vertebral body and perform the cement injection.
CONCLUSIONS: This is the first report of the technical peculiarities of
percutaneous vertebroplasty in patients under medical treatment with denosumab.
According to our experience, because of its RANKL-mediated effects on
osteoclasts activity, denosumab has been shown to induce a fast and marked
sclerotic response on vertebral bodies that may not be accompanied by a
satisfactory improvement in pain control (especially in patients with mechanical
type of pain) and which may actually prevent the successful performance of
percutaneous vertebroplasty. Therefore, it is of paramount importance that
future studies evaluating patients with vertebral fractures under treatment with
denosumab include long-term pain outcome measures. Additionally, further
investigation is warranted to determine the optimal order of treatment and the
best timeframe for combining percutaneous vertebroplasty and denosumab therapy
in patients presenting with acute vertebral compression fractures and refractory
axial pain. |
List the human genes encoding for the dishevelled proteins? | DVL-1
DVL-2
DVL-3 | The dishevelled gene of Drosophila is required to establish coherent arrays of
polarized cells and is also required to establish segments in the embryo. Here,
we show that loss of dishevelled function in clones, in double heterozygotes
with wingless mutants and in flies bearing a weak dishevelled transgene leads to
patterning defects which phenocopy defects observed in wingless mutants alone.
Further, polarized cells in all body segments require dishevelled function to
establish planar cell polarity, and some wingless alleles and dishevelled;
wingless double heterozygotes exhibit bristle polarity defects identical to
those seen in dishevelled alone. The requirement for dishevelled in establishing
polarity in cell autonomous. The dishevelled gene encodes a novel intracellular
protein that shares an amino acid motif with several other proteins that are
found associated with cell junctions. Clonal analysis of dishevelled in leg
discs provides a unique opportunity to test the hypothesis that the wingless
dishevelled interaction species at least one of the circumferential positional
values predicted by the polar coordinate model. We propose that dishevelled
encodes an intracellular protein required to respond to a wingless signal and
that this interaction is essential for establishing both cell polarity and cell
identity. The Drosophila dishevelled gene (dsh) encodes a secreted glycoprotein, which
regulates cell proliferation, acting as a transducer molecule for developmental
processes, including segmentation and neuroblast specification. We have isolated
and characterized cDNA clones from two different human dsh-homologous genes,
designated as DVL-1 and DVL-3. DVL-1 and DVL-3 putative protein products show
64% amino acid identity. The DVL-1 product is 50% identical to dsh and 92% to a
murine dsh homologue (Dvl-1). Both human DVL genes are widely expressed in fetal
and adult tissues, including brain, lung, kidney, skeletal muscle and heart.
DVL-1 locus maps to chromosome 1p36 and DVL-3 to chromosome 3q27. DVL-1 locus on
chromosome 1 corresponds to the murine syntenic region where Dvl-1 is located.
DVL-1 and DVL-3 are members of a human dsh-like gene family, which is probably
involved in human development. Although the precise role of these genes in
embryogenesis is only conjectural at present, the structural and evolutionary
characteristics suggest that mutations at their loci may be involved in neural
and heart developmental defects. The Wnt family of proto-oncogenes encodes secreted signaling proteins that are
required for mouse development. The Drosophila Wnt homolog, the wingless (Wg)
segment polarity gene, mediates a signal transduction pathway in which the
downstream elements appear to be conserved through evolution. One such element,
the dishevelled gene product, becomes hyperphosphorylated and translocates to
the plasma membrane in response to Wg (Yanagawa et al., 1995). We report here
that the mouse Dishevelled-1 (Dvl-1) and Dishevelled-2 genes encode proteins
that are differentially localized in Wnt-overexpressing PC12 cell lines
(PC12/Wnt). Whereas Dvl-1 and Dvl-2 proteins are limited to the soluble fraction
of parental PC12 cells, PC12/Wnt cells display a subset of Dvl-1 protein
associated with the membrane and Dvl-2 protein with the cytoskeletal fraction.
These results suggest a conserved role for Dvl in Wnt/wg signal transduction. The Dvl-1 gene on chromosome 1p36 belongs to a family of highly conserved
secreted proteins which regulates embryonic induction, generation of cell
polarity and specification of cell fate through activation of Wnt signaling
pathways. Wnt signaling activates the gene encoding DVL-1; the latter suppresses
beta-catenin by promoting its degradation through enhanced inactivation of
glycogen-synthase-kinase 3 (GSK3). Here we demonstrate increased expression of
DVL-1 mRNA in over two thirds of primary cervical squamous cell cancers (11 of
15 cases) when compared to corresponding non-cancerous uterine squamous cell
tissues. In addition, we noted up-regulation of cyclin D1, a downstream effector
of Wnt signal pathway in cervical cancer. Immunohistochemical staining
demonstrated that DVL-1 protein was prominent in the cytoplasm of cancer cells
whereas it was unreactive in the surrounding normal cervical squamous cells.
These data indicate that amplification and increased expression of the DVL-1
gene may play some role in the development of a portion of human cervical
squamous cell cancer through derangement of the Wnt signaling pathway. AIMS AND BACKGROUND: The Wnt/beta-catenin signaling pathway is one of the main
carcinogenic mechanisms in human maligcies including prostate cancer.
Recently, the DVL1 gene was identified as a middle molecule of the
Wnt/beta-catenin signaling pathway. In addition, alterations of the DVL1 gene
have been reported in breast and cervical cancer. The abnormality of
beta-catenin in prostate cancer has been well studied, so the examination of the
DVL1 gene in prostate cancer is appealing.
METHODS: We investigated DVL1 messenger RNA alterations by semiquantitative PCR
(SQ-PCR) in 20 primary prostate cancers and assessed the protein expression by
immunohistochemical analysis in the same samples. In addition, DVL1 and
beta-catenin protein expression was evaluated with a new validated set of 20
prostate cancers.
RESULTS: SQ-PCR revealed significant overexpression of DVL1 in prostate cancer
(65%). Upregulation of the DVL1 gene product in prostate cancer was confirmed by
immunostaining. With SQ-PCR and immunostaining, none of the cases showed
underexpression or downregulation of DVL1. In addition, the data showed
correlations between DVL1 mRNA and protein expression. Interestingly, the
expression level of DVL1 increased with worsening histological grade. In
addition, a correlation between DVL1 expression and beta-catenin expression was
confirmed.
CONCLUSIONS: DVL1 was overexpressed in prostate cancer and its overexpression
might be related to prostate cancer progression through the Wnt/beta-catenin
pathway. Dishevelled (Dvl) proteins are key transducers of Wnt signaling encoded by
members of a multi-gene family in vertebrates. We report here the divergent,
tissue-specific expression patterns for all three Dvl genes in Xenopus embryos,
which contrast dramatically with their expression patterns in mice. Moreover, we
find that the expression patterns of Dvl genes in the chick diverge
significantly from those of Xenopus. In addition, in hemichordates, an outgroup
to chordates, we find that the one Dvl gene is dynamically expressed in a
tissue-specific manner. Using knockdowns, we find that Dvl1 and Dvl2 are
required for early neural crest specification and for somite segmentation in
Xenopus. Most strikingly, we report a novel role for Dvl3 in the maintece of
gene expression in muscle and in the development of the Xenopus sclerotome.
These data demonstrate that the expression patterns and developmental functions
of specific Dvl genes have diverged significantly during chordate evolution. Hirschsprung's disease (HSCR) is a congenital disorder of the enteric nervous
system and is characterized by an absence of enteric ganglion cells in terminal
regions of the gut during development. Dishevelled (DVL) protein is a
cytoplasmic protein which plays pivotal roles in the embryonic development. In
this study, we explore the cause of HSCR by studying the expression of DVL-1 and
DVL-3 genes and their proteins in the aganglionic segment and the ganglionic
segment of colon in HSCR patients.
MATERIALS AND METHODS: Specimen of aganglionic segment and ganglionic segment of
colon in 50 cases of HSCR patients. Expression levels of mRNA and proteins of
DVL-1 and DVL-3 were confirmed by quantitative real-time PCR (qRT-PCR), western
blot and immunohistochemistry staining between the aganglionic segment and the
ganglionic segment of colon in HSCR patients.
RESULTS: The mRNA expression of DVL-1 and DVL-3 were 2.06 fold and 3.12 fold in
the aganglionic segment colon tissues compared to the ganglionic segment,
respectively. Similarly, the proteins expression of DVL-1 and DVL-3 were higher
(39.71 ± 4.53 vs and 53.90 ± 6.79 vs) in the aganglionic segment colon tissues
than in the ganglionic segment (15.01 ± 2.66 and 20.13 ± 3.63) by western blot.
Besides, immunohistochemical staining showed that DVL-1 and DVL-3 have a
significant increase in mucous and submucous layers from aganglionic colon
segments compared with ganglionic segments.
CONCLUSION: The study showed an association of DVL-1 and DVL-3 with HSCR, it may
play an important role in the pathogenesis of HSCR. |
Name synonym of Acrokeratosis paraneoplastica. | Acrokeratosis paraneoplastic (Bazex syndrome) is a rare, but distinctive paraneoplastic dermatosis characterized by erythematosquamous lesions located at the acral sites and is most commonly associated with carcinomas of the upper aerodigestive tract. | Acrokeratosis paraneoplastica of Bazex is a rare cutaneous syndrome associated
with maligt neoplasms of the pulmonary and upper gastrointestinal tract, or
cervical metastatic adenopathy, usually seen in middle-aged white men. We
present a unique case of Bazex syndrome in that the patient was young, black,
and a woman. A 55-year-old white man born in Canada presented with all the clinical features
of acrokeratosis paraneoplastica of Bazex. He showed the characteristic
violaceous erythema and scaling of the nose and face, the aural helices, and the
palmoplantar regions with severe nail dystrophy. Extensive examinations failed
to reveal any associated maligcy up to 5 months after the onset of the skin
eruption. While the skin was improving, and although the patient was still
asymptomatic except for a weight loss of 5 kg, evidence of metastatic squamous
cell carcinoma of the cervical region was obtained. Only palliative treatment
could be undertaken. The bizarre clinical aspects of the syndrome are reviewed. Acrokeratosis paraneoplastica (Bazex' syndrome) is a rare but clinically
distinctive dermatosis that has been associated in all reported cases, to our
knowledge, with either a primary maligt neoplasm of the upper aerodigestive
tract or metastatic cancer to the lymph nodes of the neck. Acrokeratosis
paraneoplastica was found in a 53-year-old black man with squamous cell
carcinoma of the tonsil. A distinctive series of changes was found on
histopathologic examination of biopsy specimens taken from his skin lesions, and
direct immunofluorescence microscopy of both lesional and nonlesional skin
specimens showed immunoglobulin and complement deposition on the epidermal
basement membrane. The skin lesions largely resolved following radiation therapy
of the neoplasm and of the presumably involved lymph nodes. The focus of this article is acrokeratosis paraneoplastica, one of two disorders
that have acquired the eponym Bazex syndrome. To date, all of the patients
reported in the literature have had an underlying neoplasm, most commonly
squamous cell carcinoma of the upper aerodigestive tract. In this review of 113
cases of acrokeratosis paraneoplastica (mean age, 61 years; 105 males, 8
females), the psoriasiform lesions preceded the diagnosis of the associated
maligcy in 73 (67%) of 109 patients, whereas the cutaneous manifestations
followed the diagnosis of the neoplasm in only 16 (15%) of 109; in the
remainder, the onset of the skin lesions and the diagnosis of the tumor occurred
simultaneously. Therefore, awareness of the cutaneous signs of Bazex syndrome is
of obvious importance to dermatologists. Evidence in favor of the paraneoplastic
nature of this disease is as follows: in 81 (93%) of 87 patients with adequate
clinical descriptions, the skin lesions either improved significantly (or
resolved) when the underlying neoplasm was treated or they remained unchanged in
the setting of persistent disease. Occasionally, the reappearance of skin
lesions has signaled a recurrence of the tumor. A 65-year-old white man presented with all the clinical features of
acrokeratosis paraneoplastica of Bazex, characterized by violaceous erythema and
scaling of the nose, aural helices, fingers, and toes, with keratoderma and
severe nail dystrophy. Examination of the patient for possible associated
maligcy disclosed an asymptomatic squamous cell carcinoma at the
oropharyngeal region. The skin lesions resolved almost completely following
radiation therapy of the neoplasm, but the onychodystrophy persisted. This case
report illustrates the importance of early recognition of Bazex syndrome. Bazex syndrome, or acrokeratosis paraneoplastica, is a cutaneous paraneoplastic
syndrome characterized by psoriasiform lesions associated with, usually, a
squamous cell carcinoma of the upper aerodigestive tract. We present a case of
Bazex syndrome associated with metastatic cervical squamous cell carcinoma with
an unknown primary. The features of the condition are discussed in the light of
current knowledge. PURPOSE: Obligatory cutaneous paraneoplastic disorders comprising acanthosis
nigricans maligna, erythema gyratum repens, paraneoplastic pemphigus,
hypertrichosis lanuginosa acquisita, erythema necrolyticum migrans and
acrokeratosis paraneoplastica are rare. However, as markers of an underlying
internal maligcy they are of utmost importance for the patient. Acrokeratosis
paraneoplastica (first described by Gougerot and Rupp in 1922) was named after
Bazex who had then reported several cases in a French dermatological journal
since 1965 (Bazex et al. in Bull Soc Fr Dermatol Syphiligr 72:182, 1965; Bazex
and Griffiths in Br J Dermatol 102:301-306, 1980).
METHOD: The study is a clinical case of a patient with acrokeratosis
paraneoplastica.
RESULTS: the patient was later diagnosed with a cervical lymph node metastasis
and thereafter with a primary squamous cell carcinoma of the left upper lobe and
upon treatment responded with the clearing of the skin changes.
CONCLUSION: Identification of a paraneoplastic syndrome may enhance the earlier
diagnosis of the associated tumor and may thus enable curative treatment. Acrokeratosis paraneoplastica (Bazex's syndrome) is a rare obligate
paraneoplastic dermatosis characterized by erythematosquamous lesions localized
symmetrically at the acral sites. The condition almost exclusively affects
Caucasian men older than 40 years. It is usually associated with primary
maligt neoplasms of the upper aerodigestive tract. In most cases, the skin
changes precede the clinical manifestation of the underlying neoplasm. The
dermatosis can be cured only by removal of the underlying carcinoma. We describe
a case of acrokeratosis paraneoplastica associated with a retroperitoneal
liposarcoma in a 71-year-old Caucasian man. The liposarcoma was surgically
removed but recurred several times, with acrokeratosis paraneoplastica showing a
parallel development. We, therefore, add liposarcoma to the growing list of
maligt neoplasms associated with acrokeratosis paraneoplastica. BACKGROUND: Bazex syndrome (acrokeratosis paraneoplastica) is a rare
paraneoplastic syndrome that usually occurs in males over 40 years old and is
particularly associated with squamous cell carcinoma of the upper aerodigestive
tract and adenopathy above the diaphragm.
OBJECTIVE: The objectives of our article are (1) to describe a unique case of
acrokeratosis paraneoplastica and (2) to review the current literature regarding
skin findings, commonly associated neoplasms, and treatment options relative to
this condition.
PATIENT: We describe a 68-year-old female with lobular breast carcinoma,
complicated by local and distant recurrences, who presented with a 1-year
history of prominent acral skin and nail changes.
RESULTS: Our patient's clinical skin findings improved significantly following
treatment and partial remission of her underlying maligcy.
CONCLUSIONS: Our patient represents one of few females described with this
syndrome, which is especially rare in association with lobular breast carcinoma.
Further, the patient's presentation is unique as she was discovered to
demonstrate laboratory findings consistent with coexistent porphyria cutanea
tarda and relative zinc deficiency. BACKGROUND: Acrokeratosis paraneoplastica Bazex (APB) is a very rare disease in
the group of obligate paraneoplastic dermatoses, associated mostly with squamous
cell carcinoma of the upper aerodigestive tract and metastatic cervical
lymphadenopathy. The disease is characterized by violaceous erythemosquamous
changes on the acral regions. This entity was first reported by Bazex in 1965.
About 160 cases have been presented so far.
CASE REPORT: We presented a patient with a three-month history of violaceous
erythema, edema, erosions and scaling on the acral regions, elbows and knees and
severe nail dystrophy. When the diagnosis was established, he did not have any
symptom of internal maligcy. Esophagogastroscopy revealed ulcerovegetant
lesion of the esophagus, while histology showed squamocellular invasive
carcinoma. Surgical tumor removal resulted in significant improvement of skin
changes in 15 days. Unfortunately, four months later, extensive skin lesions
pointed to metastasis of squamous cell carcinoma.
CONCLUSION: Skin changes can precede a few years the first manifestations of
neoplasia. The course of the disease in our patient proved that APB is a
specific marker of underlying maligcy. Acrokeratosis paraneoplastica is a rare paraneoplastic syndrome commonly
affecting males over 40 years of age. There exists a strong association with
squamous cell carcinoma (SCC) of the upper aerodigestive tract or cervical
metastatic disease originating from an unknown primary. We report a case
associated with SCC of the right tonsil with persistent paraneoplastic cutaneous
lesions 2 years after successful treatment of the underlying neoplasm. Acrokeratosis paraneoplastic (Bazex syndrome) is a rare, but distinctive
paraneoplastic dermatosis characterized by erythematosquamous lesions located at
the acral sites and is most commonly associated with carcinomas of the upper
aerodigestive tract. We report a 58-year-old female with a history of a
pigmented rash on her extremities, thick keratotic plaques on her hands, and
brittle nails. Chest imaging revealed a right upper lobe mass that was proven to
be small cell lung carcinoma. While Bazex syndrome has been described in the
dermatology literature, it is also important for the radiologist to be aware of
this entity and its common presentations. |
Which are the classes of anti-arrhythmic drugs according to Vaughan-Williams classification? | Antiarrhythmic drugs can be divided into four Vaughan Williams classes (I-IV). Class I antiarrhythmic agents have as a common action, blockade of the sodium channels. Class II agents are antisympathetic drugs, particularly the beta-adrenoceptor blockers. Class-III antiarrhythmics have as a common action the potassium-channel blockade. Class IV antiarrhythmic drugs are calcium channel blockers. | The present paper reviews classification and mode of action of agents that
suppress extrasystoles and tachyarrhythmias. These are classified according to
their electrophysiological effects observed in isolated cardiac tissues in vitro
(Vaughan Williams, 1989). Fast sodium channel blockers (class I) which reduce
the upstroke velocity of the action potential are usually subclassified into
three groups, class I A-C, according to their effect on the action potential
duration. Beta-adrenergic antagonists (class II) exert their effects by
antagonizing the electrophysiological effects of beta-adrenergic catecholamines.
Class III antiarrhythmic agents (eg amiodarone) prolong the action potential and
slow calcium channel blockers (class IV) suppress the calcium inward current and
calcium-dependent action potentials. The classification of antiarrhythmic drugs
is still under debate. This particularly applies to agents of class I and III.
The effect of class I agents is frequency-dependent because the binding affinity
of these drugs to the sodium channel is modulated by the state of the channel
(modulated receptor hypothesis). Class I agents bind to the channel in the
activated and inactivated state and dissociate from the channel in the rested
state. This occurs at a drug-specific rate so that class I agents can be
subclassified into only two groups, namely in those of the slow- and
fast-recovery type respectively (time constant of reactivation greater or
smaller than 1 s). Slow-recovery class I agents affect regular action potentials
at normal heart rates which can more easily lead to a lengthening of the QRS
duration in the ECG, to conduction disturbances and hence to pro-arrhythmic
effects.(ABSTRACT TRUNCATED AT 250 WORDS) Antiarrhythmic drugs can be divided into four Vaughan Williams classes (I-IV)
according to defined electrophysiological effects on the myocardium. Thus, the
Vaughan Williams classification also coincides with the main myocardial targets
of the antiarrhythmics, i.e., myocardial sodium-, potassium-, and
calcium-channels or beta-adrenergic receptors. A more detailed characterization
which is also based on the myocardial targets of a drug is given by the
"Sicilian Gambit" approach of classification. Nevertheless, the appropriate drug
for the management of a given clinical arrhythmia has to be chosen according to
the electrophysiological effects of the respective drug. A main determit of
the antiarrhythmic or proarrhythmic properties of a drug is the frequency
dependence of its electrophysiological effects. The sodium-channel blockade
induced by class-I substances is enhanced with increasing heart rates. Thus,
class-I antiarrhythmics can be subclassified as substances showing a more
exponential, an approximately linear, or rather saturated block-frequency
relation. Class-III antiarrhythmics (potassium-channel blockade) can be further
differentiated according to the component of the delayed rectifier potassium
current (IK) which is inhibited by a drug. Class-III drugs inhibiting
selectively the rapidly activating and deactivating IKr component exhibit a
marked reverse rate dependence, i.e., the drug induced prolongation of the
cardiac action potential is minimized at high rates. On the other hand, during
bradycardia the pronounced action potential prolongation may cause early
afterdepolarizations and triggered activity leading to torsades de pointes
arrhythmias (acquired QT syndrome). Class-III substances inhibiting the slowly
activating IKs component are currently under investigation and are expected to
show a direct rate dependence. Experimental data available so far point to an
action potential prolonging effect at least independent of rate. However, it is
uncertain whether proarrhythmic effects can be thus avoided, especially in light
of the fact that one form of congenital QT syndrome (LQT1) seems to be linked to
dysfunction of the IKs-channel. Antiarrhythmic agents are traditionally classified according to Vaughan Williams
into four classes of action. Class I antiarrhythmic agents include most of the
drugs traditionally thought of as antiarrhythmics, and have as a common action,
blockade of the fast-inward sodium channel on myocardium. These agents have a
very significant toxicity, and while they are being used less, therapeutic drug
monitoring (TDM) does significantly increase the safety with which they can be
administered. Class II agents are antisympathetic drugs, particularly the
b-adrenoceptor blockers. These are generally safe agents which do not normally
require TDM. Class III antiarrhythmic agents include sotalol and amiodarone. TDM
can be useful in the case of amiodarone to monitor compliance and toxicity but
is generally of little value for sotalol. Class IV antiarrhythmic drugs are the
calcium channel blockers verapamil and diltiazem. These are normally monitored
by haemodynamic effects, rather than using TDM. Other agents which do not fall
neatly into the Vaughan Williams classification include digoxin and perhexiline.
TDM is very useful for monitoring the administration (and particularly the
safety) of both of these agents. |
Which are the different isoforms of the mammalian Notch receptor? | Notch signaling is an evolutionarily conserved mechanism, used to regulate cell fate decisions. Four Notch receptors have been identified in man: Notch-1, Notch-2, Notch-3 and Notch-4. | Notch signaling is an evolutionarily conserved mechanism, used to regulate cell
fate decisions. Four Notch receptors have been identified in man (Notch-1 to
-4). In this study, semiquantitative reverse transcription polymerase chain
reaction (RT-PCR) and immunohistochemistry were used to examine the expression
pattern of Notch receptor genes in whole adult human liver and isolated liver
cell preparations. All 4 receptors were expressed in the adult liver, with no
significant differences in the levels of Notch-1, -2, and -4 messenger RNA
(mRNA) between normal and diseased liver. However, Notch-3 expression appeared
to be increased in diseased tissue. The distribution of Notch-1 and -4 in normal
tissue was similar, with Notch-1 also detectable at low levels in the sinusoidal
endothelium. Notch-2 expression was more widely distributed, and detectable in
hepatocytes, medium-sized bile ducts, and the sinusoidal endothelium. Notch-3
expression was seen on hepatocytes, with weaker expression detectable in portal
veins, hepatic arteries, and the sinusoids. In normal liver tissue Notch-1, -2,
and -3 were found to be coexpressed on bile duct epithelium; however, with the
exception of Notch-3 in primary sclerosing cholangitis (PSC) livers, expression
was absent on proliferating ductules in all disease states examined.
Interestingly, the expression of Notch-2 and -3 was associated with numerous
small vessels within the portal tract septa of diseased tissue. The absence of
Notch receptor expression on proliferating bile ductules and its presence on
neovessels suggests that Notch signaling may be important for normal bile duct
formation and the aberrant neovascularization seen in diseased liver tissue. BACKGROUND: The interaction of Notch receptors with their transmembrane ligands
Delta and Jagged plays an important role not only in the organization of a
variety of tissues but also in several genetic disorders and cancer development.
The functional involvement of the Notch signaling in rheumatoid arthritis (RA)
has been reported previously, but the expression profile of Notch-related
molecules, as well as their relation with clinicopathological parameters,
remains unclear.
METHODS: In this study, we analyzed the immunohistochemical staining pattern of
four Notch receptors (Notch1-4) and their ligands (Delta1 and Jagged1) in 14
synovial tissues obtained from 14 RA patients.
RESULTS: Notch2 and Notch4 were expressed in limited areas in a few samples or
in small blood vessels, respectively. Notch1, Notch3, Delta1, and Jagged1 were
overexpressed in the synovial lining and sublining cells on synovial
hyperplastic lesions in all samples. Notch1 expression was also observed in T
and B lymphocytes of lymphoid follicles independently. Notch1 and Notch3
expression overlapped with that of Jagged1, as determined by confocal
microscopy. Activation of Notch1 signaling in the RA synovium was identified
using a specific antibody to the cleaved form of Notch1. The expression of these
molecules did not show any correlation with clinicopathological parameters.
CONCLUSIONS: Our results suggest that Notch signaling is activated in RA
synovium but does not necessarily reflect the pathological condition of RA. Hepatoblastoma is a pediatric maligcy characterized by the uncontrolled
proliferation of immature hepatocytes (hepatoblasts). This disease is diagnosed
primarily in children younger than 5 years and is disproportionately observed in
former premature infants. Cytogenetically, hepatoblastoma is characterized by
numerical aberrations, as well as unbalanced translocations involving the
proximal region of chromosome 1q. The NOTCH2 gene has been mapped to this locus,
and it is well established that the NOTCH gene family is an important regulator
of several developmental pathways. Specifically, the NOTCH2 protein is known to
delay hepatoblast maturation during early hepatic organogenesis, and the
reduction of NOTCH2 expression correlates with the differentiation of
hepatoblasts into hepatocytes and biliary cells in the developing liver. We
hypothesized that NOTCH2 is involved in the pathogenesis of hepatoblastoma by
maintaining a population of undifferentiated hepatoblasts. We studied the
immunohistochemical expression of NOTCH2 and its isoforms NOTCH1, NOTCH3, and
NOTCH4 and the NOTCH2 primary ligand JAGGED1 in hepatoblastomas. Compared with
the normal liver, an increased level of NOTCH2 expression was seen in 22 of 24
(92%) hepatoblastomas. There was no significant staining for other NOTCH
isoforms and JAGGED1 in hepatoblastomas. Therefore, we suggest that NOTCH2
expression and activation, independent of JAGGED1 expression, may contribute to
the pathogenesis of hepatoblastoma. In the hepatoblastoma sinusoidal
vasculature, we saw NOTCH3 and NOTCH1 expression. These observations have
potential implications with regard to therapeutic targeting of the NOTCH
signaling pathway in hepatoblastomas. Notch signalling occurs via direct cell-cell interactions and plays an important
role in linking the fates of neighbouring cells. There are four different
mammalian Notch receptors that can be activated by five cell surface ligands.
The ability to inhibit specific Notch receptors would help identify the roles of
individual family members and potentially provide a means to study and control
cell differentiation. Anti-Notch antibodies in the form of single chain Fvs were
generated from an antibody phage display library by selection on either the
ligand binding domain or the negative regulatory region (NRR) of Notch1 and
Notch2. Six antibodies targeting the NRR of Notch1 and four antibodies
recognising the NRR of Notch2 were found to prevent receptor activation in
cell-based luciferase reporter assays. These antibodies were potent, highly
specific inhibitors of individual Notch receptors and interfered with endogenous
signalling in stem cell systems of both human and mouse origin.
Antibody-mediated inhibition of Notch efficiently down-regulated transcription
of the immediate Notch target gene hairy and enhancer of split 5 (Hes5) in both
mouse and human neural stem cells and revealed a redundant regulation of Hes5 in
these cells as complete down-regulation was seen only after simultaneous
blocking of Notch1 and Notch2. In addition, these antibodies promoted
differentiation of neural stem cells towards a neuronal fate. In contrast to the
widely used small molecule γ-secretase inhibitors, which block all 4 Notch
receptors (and a multitude of other signalling pathways), antibodies allow
blockade of individual Notch family members in a highly specific way. Specific
inhibition will allow examination of the effect of individual Notch receptors in
complex differentiation schemes regulated by the co-ordinated action of multiple
signalling pathways. Cerebral Autosomal Domit Arteriopathy with Subcortical Infarcts and
Leukoencephalopathy (CADASIL) is the best understood cause of domitly
inherited stroke and results from NOTCH3 mutations that lead to NOTCH3 protein
accumulation and selective arterial smooth muscle degeneration. Previous studies
show that NOTCH3 protein forms multimers. Here, we investigate protein
interactions between NOTCH3 and other vascular Notch isoforms and characterize
the effects of elevated NOTCH3 on smooth muscle gene regulation. We demonstrate
that NOTCH3 forms heterodimers with NOTCH1, NOTCH3, and NOTCH4. R90C and C49Y
mutant NOTCH3 form complexes which are more resistant to detergents than wild
type NOTCH3 complexes. Using quantitative NOTCH3-luciferase clearance assays, we
found significant inhibition of mutant NOTCH3 clearance. In coculture assays of
NOTCH function, overexpressed wild type and mutant NOTCH3 significantly
repressed NOTCH-regulated smooth muscle transcripts and potently impaired the
activity of three independent smooth muscle promoters. Wildtype and R90C
recombit NOTCH3 proteins applied to cell cultures also blocked canonical
Notch fuction. We conclude that CADASIL mutants of NOTCH3 complex with NOTCH1,
3, and 4, slow NOTCH3 clearance, and that overexpressed wild type and mutant
NOTCH3 protein interfere with key NOTCH-mediated functions in smooth muscle
cells. |
Which are the major characteristics of cellular senescence? | The defining characteristics of cellular senescence are altered morphology, arrested cell-cycle progression, development of aberrant gene expression with proinflammatory behavior, and telomere shortening. | Although reactive oxygen species have been proposed to play a major role in the
aging process, the exact molecular mechanisms remain elusive. In this study we
investigate the effects of a perturbation in the ratio of Cu/Zn-superoxide
dismutase activity (Sod1 dismutases .O2-to H2O2) to glutathione peroxidase
activity (Gpx1 catalyses H2O2 conversion to H2O) on cell growth and development.
Our data demonstrate that Sod1 transfected cell lines that have an elevation in
the ratio of Sod1 activity to Gpx1 activity produce higher levels of H2O2 and
exhibit well characterised markers of cellular senescence viz. slower
proliferation and altered morphology. On the contrary, Sod1 transfected cell
lines that have an unaltered ratio in the activity of these two enzymes, have
unaltered levels of H2O2 and fail to show characteristics of senescence.
Furthermore, fibroblasts established from individuals with Down syndrome have an
increase in the ratio of Sod1 to Gpx1 activity compared with corresponding
controls and senesce earlier. Interestingly, cells treated with H2O2 also show
features of senescence and/or senesce earlier. We also show that Cip1 mRNA
levels are elevated in Down syndrome cells, Sod1 transfectants with an altered
Sod1 to Gpx1 activity ratio and those treated with H2O2, thus suggesting that
the slow proliferation may be mediated by Cip1. Furthermore, our data
demonstrate that Cip1 mRNA levels are induced by exposure of cells to H2O2.
These data give valuable insight into possible molecular mechanisms that
contribute tribute to cellular senescence and may be useful in the evolution of
therapeutic strategies for aging. Recent research has shown that inserting a gene for the protein component of
telomerase into senescent human cells reextends their telomeres to lengths
typical of young cells, and the cells then display all the other identifiable
characteristics of young, healthy cells. This advance not only suggests that
telomeres are the central timing mechanism for cellular aging, but also
demonstrates that such a mechanism can be reset, extending the replicative life
span of such cells and resulting in markers of gene expression typical of
"younger" (ie, early passage) cells without the hallmarks of maligt
transformation. It is now possible to explore the fundamental cellular
mechanisms underlying human aging, clarifying the role played by replicative
senescence. By implication, we may soon be able to determine the extent to which
the major causes of death and disability in aging populations in developed
countries-cancer, atherosclerosis, osteoarthritis, macular degeneration, and
Alzheimer dementia--are attributable to such fundamental mechanisms. If they are
amenable to prevention or treatment by alteration of cellular senescence, the
clinical implications have few historic precedents. |
Orteronel was developed for treatment of which cancer? | Orteronel was developed for treatment of castration-resistant prostate cancer. | A novel naphthylmethylimidazole derivative 1 and its related compounds were
identified as 17,20-lyase inhibitors. Based on the structure-activity
relationship around the naphthalene scaffold and the results of a docking study
of 1a in the homology model of 17,20-lyase, the
6,7-dihydro-5H-pyrrolo[1,2-c]imidazole derivative (+)-3c was synthesized and
identified as a potent and highly selective 17,20-lyase inhibitor. Biological
evaluation of (+)-3c at a dose of 1mg/kg in a male monkey model revealed marked
reductions in both serum testosterone and dehydroepiandrosterone concentrations.
Therefore, (+)-3c (termed orteronel [TAK-700]) was selected as a candidate for
clinical evaluation and is currently in phase III clinical trials for the
treatment of castration-resistant prostate cancer. PURPOSE: The androgen receptor pathway remains active in men with prostate
cancer whose disease has progressed following surgical or medical castration.
Orteronel (TAK-700) is an investigational, oral, nonsteroidal, selective,
reversible inhibitor of 17,20-lyase, a key enzyme in the production of
androgenic hormones.
EXPERIMENTAL DESIGN: We conducted a phase I/II study in men with progressive,
chemotherapy-naïve, metastatic castration-resistant prostate cancer, and serum
testosterone <50 ng/dL. In the phase I part, patients received orteronel 100 to
600 mg twice daily or 400 mg twice a day plus prednisone 5 mg twice a day. In
phase II, patients received orteronel 300 mg twice a day, 400 mg twice a day
plus prednisone, 600 mg twice a day plus prednisone, or 600 mg once a day
without prednisone.
RESULTS: In phase I (n = 26), no dose-limiting toxicities were observed and 13
of 20 evaluable patients (65%) achieved ≥50% prostate-specific antigen (PSA)
decline from baseline at 12 weeks. In phase II (n = 97), 45 of 84 evaluable
patients (54%) achieved a ≥50% decline in PSA and at 12 weeks, substantial mean
reductions from baseline in testosterone (-7.5 ng/dL) and
dehydroepiandrosterone-sulfate (-45.3 μg/dL) were observed. Unconfirmed partial
responses were reported in 10 of 51 evaluable phase II patients (20%). Decreases
in circulating tumor cells were documented. Fifty-three percent of phase II
patients experienced grade ≥3 adverse events irrespective of causality; most
common were fatigue, hypokalemia, hyperglycemia, and diarrhea.
CONCLUSIONS: 17,20-Lyase inhibition by orteronel was tolerable and results in
declines in PSA and testosterone, with evidence of radiographic responses. Orteronel (also known as TAK-700) is a novel hormonal therapy that is currently
in testing for the treatment of prostate cancer. Orteronel inhibits the 17,20
lyase activity of the enzyme CYP17A1, which is important for androgen synthesis
in the testes, adrenal glands and prostate cancer cells. Preclinical studies
demonstrate that orteronel treatment suppresses androgen levels and causes
shrinkage of androgen-dependent organs, such as the prostate gland. Early
reports of clinical studies demonstrate that orteronel treatment leads to
reduced prostate-specific antigen levels, a marker of prostate cancer tumor
burden, and more complete suppression of androgen synthesis than conventional
androgen deprivation therapies that act in the testes alone. Treatment with
single-agent orteronel has been well tolerated with fatigue as the most common
adverse event, while febrile neutropenia was the dose-limiting toxicity in a
combination study of orteronel with docetaxel. Recently, the ELM-PC5 Phase III
clinical trial in patients with advanced-stage prostate cancer who had received
prior docetaxel was unblinded as the overall survival primary end point was not
achieved. However, additional Phase III orteronel trials are ongoing in men with
earlier stages of prostate cancer. Author information:
(1)Karim Fizazi, Institut Gustave Roussy, University of Paris Sud, Villejuif;
Stephane Oudard, Université Paris Descartes, Paris, France; Robert Jones,
Institute of Cancer Sciences, University of Glasgow, Glasgow; Johann De Bono,
The Institute of Cancer Research, London, United Kingdom; Eleni Efstathiou,
University of Athens Medical School, Athens; George Fountzilas, Aristotle
University of Thessaloniki School of Medicine, Thessaloniki, Greece; Fred Saad,
University of Montreal Hospital Center, Montreal, Canada; Ronald de Wit, Erasmus
University Medical Center, Rotterdam, the Netherlands; Felipe Melo Cruz, ABC
Foundation School of Medicine, Santo André; Flavio Carcano, Hospital de Cancer
de Barretos, Barretos, Brazil; Albertas Ulys, Institut of Oncology, Vilnius
University, Vilnius, Lithuania; Neeraj Agarwal, Huntsman Cancer Institute,
University of Utah, Salt Lake City, UT; David Agus, University of Southern
California, Los Angeles, CA; Daniel P. Petrylak, Yale University Cancer Center,
New Haven, CT; Shih-Yuan Lee, Bindu Tejura, Niels Borgstein, Takeda
Pharmaceuticals International; Iain J. Webb, Millennium: The Takeda Oncology
Company, Cambridge, MA; Robert Dreicer, Cleveland Clinic, Cleveland, OH; Joaquim
Bellmunt, University Hospital del Mar-IMIM, Barcelona, Spain.
[email protected].
(2)Karim Fizazi, Institut Gustave Roussy, University of Paris Sud, Villejuif;
Stephane Oudard, Université Paris Descartes, Paris, France; Robert Jones,
Institute of Cancer Sciences, University of Glasgow, Glasgow; Johann De Bono,
The Institute of Cancer Research, London, United Kingdom; Eleni Efstathiou,
University of Athens Medical School, Athens; George Fountzilas, Aristotle
University of Thessaloniki School of Medicine, Thessaloniki, Greece; Fred Saad,
University of Montreal Hospital Center, Montreal, Canada; Ronald de Wit, Erasmus
University Medical Center, Rotterdam, the Netherlands; Felipe Melo Cruz, ABC
Foundation School of Medicine, Santo André; Flavio Carcano, Hospital de Cancer
de Barretos, Barretos, Brazil; Albertas Ulys, Institut of Oncology, Vilnius
University, Vilnius, Lithuania; Neeraj Agarwal, Huntsman Cancer Institute,
University of Utah, Salt Lake City, UT; David Agus, University of Southern
California, Los Angeles, CA; Daniel P. Petrylak, Yale University Cancer Center,
New Haven, CT; Shih-Yuan Lee, Bindu Tejura, Niels Borgstein, Takeda
Pharmaceuticals International; Iain J. Webb, Millennium: The Takeda Oncology
Company, Cambridge, MA; Robert Dreicer, Cleveland Clinic, Cleveland, OH; Joaquim
Bellmunt, University Hospital del Mar-IMIM, Barcelona, Spain. Collaborators: Troon S, Underhill C, Dittrich C, Krainer M, Kramer G, Loidl W,
Pummer K, Belyakovskiy V, Polyakov S, Goeminne JC, Hoekx L, Luyten D, Van Poppel
H, Werbrouck P, Azambuja A, Barrios C, Brust L, Cabral Filho S, Carcano F, Cruz
F, Damião R, Delgado G, Diógenes Â, Dzik C, Faccio A, de Faria G, Faulhaber A,
Ferdes H, Ferreira U, Filho R, Franke F, Girotto G, Koff W, Kussumoto C,
Malzyner A, de Moraes A, Padílha S, de Pádua C, Pinto L, Portella M, Reiriz A,
da Silva Teixeira V, Vieiralves L, Dimitrov B, Dudov A, Micheva R, Petrov P,
Taskova V, Carmel M, Casey R, Chin J, Jacobson A, Jansz G, Kapoor A, Kinahan T,
Love W, Martin AG, Saad F, Trachtenberg J, Webster T, Acevedo Gaete A, Arén
Frontera O, Leyton Naranjo R, Miranda Benabarre A, Pastor Arroyo P, Neira Reyes
L, Ramirez Pinto G, Restrepo Molina J, Grgic M, Babjuk M, Domes L, Jansa J,
Lukes M, Pavlik I, Zachoval R, Kahu J, Tamm T, Marttila T, Tammela T, Vaarala M,
Vitanen J, Bompas E, Colombel M, Delva R, Deplanque G, Fizazi K, Flechon A,
Giroux J, Joly F, Lechevallier E, Mottet Auselo N, Priou F, Roubaud G, Roupret
M, Spaeth D, De La Taille A, Tourani JM, Feyerabend S, De Geeter P, Geiges G,
Gleißner J, Hammerer P, Klotz T, Kuczyk M, Marin J, Schrader A, Stenzl A,
Steuber T, Wirth M, Efstathiou E, Georgoulias V, Hatzimouratidis K, Kalofonos H,
Papandreou C, Thanos A, Leung KC, Ng C, Farkas L, Pintér J, McDermott R,
Sullivan F, Berger R, Gabizon A, Gez E, Rosenbaum E, Sella A, Semenisty V, Tavdy
E, Alabiso O, Ciuffreda L, Fratino L, Sternberg C, Tubaro A, Akakura K, Arai Y,
Egawa S, Fujimoto H, Ichikawa T, Kakehi Y, Kitamura H, Maniwa A, Miyanaga N,
Mizokami A, Nakatani T, Nishimura K, Niwakawa M, Sato F, Sugiyama T, Suzuki H,
Suzuki K, Takahashi S, Tomita Y, Ueda T, Uemura H, Yamaguchi R, Yokomizo A,
Yoshimura K, Brize A, Litavnience D, Vjaters E, Jankevicius F, Jievaltas M,
Jocys G, Ulys A, Calvo Domínguez D, González Perez J, de Leon Jaen S, Pérez O,
Rodriguez Rivera J, Valdés A, Blaisse R, Hamberg A, Loosveld O, Los M, Van Oort
I, de la Rosette J, De Vries P, Vrijhof H, de Wit R, Costello S, Davidson P,
Fong C, Gilling P, Neill M, Abrill Mendoza G, Cano Rivera J, Garcia Ahumada S,
Huaringa Leiva R, Pazos Franco A, Jablonska Z, Kmieciak R, Coelho J, Sousa N,
Bucuras C, Cebotaru C, Ciuleanu T, Jinga V, Anatolyevich I, Yurievich P, Hiang
T, Sing N, Balaz V, Brezovsky M, Kliment J, Mikulas J, Mincik I, Sokol R, Botha
M, Hart G, Kraus P, Landers G, Malan J, Bellmunt J, Castellano D, Climent Duran
M, Veiga F, González B, Pérez Gracia J, Valderrama B, Provencio M, Damber JE,
Häggman M, Nyman C, Berthold D, Fischer N, Popescu R, Stenner F, Chang YH, Ou
YC, Tsai YC, Wu HC, Wu TL, Bondarenko I, Ivashchenko P, Kobets V, Pasiechnikov
S, Semenukha V, Sernyak Y, Stus V, Bahl A, Birtle A, Chowdhury S, Crabb S, Dixit
S, Elliott P, Hoskin P, Jones R, Khoo V, MacDonald A, Malik Z, O'Sullivan J,
Simms M, Stockdale A, Agarwal N, Alter R, Anderson TC, Bailen J, Berry W, Bidair
M, Clark W, Cohn AL, Crawford E, DiSimone C, Feliciano L, Fleming MT, Forero L,
Friday B, Fruehauf JP, Gelmann E, George D, Gignac G, Given R, Gullo J,
Hainsworth J, Hajdenberg J, Haluschak JJ, Hamid O, Hammers H, Hart LL, Hussain
A, Hutson TE, Ibrahim E, Jain SK, Khojasteh A, Kohli M, Lara PN Jr, Lilly M,
Lipton A, Mackey DW, Mao SS, Mehta AR, Modiano MR, Morris M, Muscato JJ,
Nordquist LT, Richards DA, Ryan C, Sartor AO, Schnadig ID, Sieber PR, Singal R,
Smith F, Somer B, Srkalovic G, Tagawa S, Tan W, Twardowski P, Van Veldhuizen PJ,
Vogelzang N, Watkins DL, Wertheim M, Wong YN, Zhang J. OBJECTIVE: We performed a systematic review of the literature to assess the
efficacy and the safety of second-line agents targeting metastatic
castration-resistant prostate cancer (mCRPC) that has progressed after
docetaxel. Pooled-analysis was also performed, to assess the effectiveness of
agents targeting the androgen axis via identical mechanisms of action
(abiraterone acetate, orteronel).
MATERIALS AND METHODS: We included phase III randomized controlled trials that
enrolled patients with mCRPC progressing during or after first-line docetaxel
treatment. Trials were identified by electronic database searching. The primary
outcome of the review was overall survival. Secondary outcomes were radiographic
progression-free survival (rPFS) and severe adverse effects (grade 3 or higher).
RESULTS: Ten articles met the inclusion criteria for the review. These articles
reported the results of five clinical trials, enrolling in total 5047 patients.
The experimental interventions tested in these studies were enzalutamide,
ipilimumab, abiraterone acetate, orteronel and cabazitaxel. Compared to control
cohorts (active drug-treated or placebo-treated), the significant overall
survival advantages achieved were 4.8 months for enzalutamide (hazard ratio for
death vs. placebo: 0.63; 95% CI 0.53 to 0.75, P < 0.0001), 4.6 months for
abiraterone (hazard ratio for death vs. placebo: 0.66, 95% CI 0.58 to 0.75, P <
0.0001) and 2.4 months for cabazitaxel (hazard ratio for death vs.
mitoxantrone-prednisone: 0.70, 95% CI 0.59 to 0.83, p < 0.0001). Pooled analysis
of androgen synthesis inhibitors orteronel and abiraterone resulted in
significantly increased overall and progression-free survival for anti-androgen
agents, compared to placebo (hazard ratio for death: 0.76, 95% CI 0.67 to 0.87,
P < 0.0001; hazard ratio for radiographic progression: 0.7, 95% CI 0.63 to 0.77,
P < 0.00001). Androgen synthesis inhibitors induced significant increases in
risk ratios for adverse effects linked to elevated mineralocorticoid secretion,
compared to placebo (risk ratio for hypokalemia: 5.75, 95% CI 2.08 to 15.90; P =
0.0008; risk-ratio for hypertension: 2.29, 95% CI 1.02 to 5.17; P = 0.05).
CONCLUSIONS: In docetaxel-pretreated patients enzalutamide,
abiraterone-prednisone and cabazitaxel-prednisone can improve overall survival
of patients, compared to placebo or to best of care at the time of study
(mitoxantrone-prednisone). Agents targeting the androgen axis (enzalutamide,
abiraterone, orteronel) significantly prolonged rPFS, compared to placebo.
Further investigation is warranted to evaluate the benefit of combination or
sequential administration of these agents. Large-scale studies are also
necessary to evaluate the impact of relevant toxic effects observed in a limited
number of patients (e.g., enzalutamide-induced seizures, orteronel-induced
pancreatitis, and others). |
Is the monoclonal antibody Trastuzumab (Herceptin) of potential use in the treatment of prostate cancer? | Although is still controversial, Trastuzumab (Herceptin) can be of potential use in the treatment of prostate cancer overexpressing HER2, either alone or in combination with other drugs. | Antibody to the Her-2/neu gene product has been shown to inhibit the growth of
breast cancer cells overexpressing Her-2/neu and to have clinical utility in
treating breast cancer. We studied a recombit, humanized anti-Her-2/neu
antibody (Herceptin) in preclinical models of human prostate cancer. The
androgen-dependent CWR22 and LNCaP human prostate cancer xenograft models and
androgen-independent sublines of CWR22 were used. Her-2/neu staining of the
parental, androgen-dependent, and androgen-independent CWR22 tumors and LNCaP
tumors demonstrated variable Her-2/neu expression. Herceptin was administered
i.p. at a dose of 20 mg/kg twice weekly after the xenograft had been
established. No effect of Herceptin on tumor growth was observed in any of the
androgen-independent tumors; however, significant growth inhibition was observed
in both of the androgen-dependent xenograft models, CWR22 (68% growth inhibition
at the completion of the experiment; P = 0.03 for trajectories of the average
tumor volume of the groups) and LNCaP (89% growth inhibition; P = 0.002). There
was a significant increase in prostate-specific antigen (PSA) index (ng PSA/ml
serum/mm3 tumor) in Herceptin-treated androgen-dependent groups compared with
control (CWR22, 18-fold relative to pretreatment value versus 1.0-fold, P =
0.0001; LNCaP, 2.35-fold relative to pretreatment value versus 0.6-fold, P =
0.001). When paclitaxel (6.25 mg/kg s.c., five times/week) was given to animals
with androgen-dependent and -independent tumors, there was growth inhibition in
each group. Paclitaxel and Herceptin cotreatment led to greater growth
inhibition than was seen for the agents individually. Thus, in these prostate
cancer model systems, Herceptin alone has clinical activity only in the
androgen-dependent tumor and has at least an additive effect on growth, in
combination with paclitaxel, in both androgen-dependent and androgen-independent
tumors. Response to Herceptin did not correlate with the PSA levels, because the
PSA index markedly increased in the Herceptin-treated group, whereas it remained
constant in the control group. These results suggest the utility of Herceptin in
the treatment of human prostate cancer. The HER2/neu oncogene is overexpressed in human pancreatic cancer, but the
clinical significance of that overexpression is uncertain. In the present study
we investigated the antitumor efficacy of Herceptin, a new recombit humanized
anti-HER2/neu antibody, which exhibits cytostatic activity on breast and
prostate cancer cells that overexpress the HER2 oncogene. That antibody may
retard tumor growth in certain patients with those diseases. We quantified HER2
expression in various human pancreatic cancer cell lines and studied the
bioactivity of this antibody both in vitro and in vivo. Growth inhibition by
Herceptin was observed in vitro in cell lines with high levels of HER2/neu
expression. Cell lines with low levels of this protein did not respond
significantly to the antibody. In vivo we studied two different pancreatic
cancer cell lines in an orthotopic mouse model of the disease. Herceptin
treatment suppressed tumor growth in the MIA PaCa-2 tumor cell line, which
expressed high levels of HER2/neu. These data suggest that Herceptin treatment
of patients with pancreatic cancer who express high levels of the HER2/neu
oncogene may be reasonable. Docetaxel, a semisynthetic taxane, has exhibited significant single-agent
activity against prostatic tumors. In phase I/II studies, single-agent docetaxel
and the combination of docetaxel plus estramustine were effective in inducing
prostate-specific antigen reductions of > or =50% in men with
androgen-independent prostate cancer (AIPC). The underlying reason for
docetaxel's clinical activity against prostate cancer has been a focus of
ongoing research. Docetaxel is believed to have a twofold mechanism of
antineoplastic activity: (1) inhibition of microtubular depolymerization, and
(2) attenuation of the effects of bcl-2 and bcl-xL gene expression.
Taxane-induced microtubule stabilization arrests cells in the G(2)M phase of the
cell cycle and induces bcl-2 phosphorylation, thereby promoting a cascade of
events that ultimately leads to apoptotic cell death. In preclinical studies,
docetaxel had a higher affinity for tubulin and was shown to be a more potent
inducer of bcl-2 phosphorylation than paclitaxel. Laboratory evidence also
supports the clinical evaluation of docetaxel-based combinations that include
agents such as trastuzumab and/or estramustine. The pathways for
docetaxel-induced apoptosis appear to differ in androgen-dependent and
androgen-independent prostate cancer cells. Further elucidation of these
differences will be instrumental in designing targeted regimens for the
treatment of localized and advanced prostate cancer. The incidence of human epidermal growth factor receptor 2 (HER2) protein
overexpression and its prognostic value are not well characterized in patients
with prostate cancer. A phase I study was designed to evaluate
docetaxel/estramustine plus trastuzumab, a humanized monoclonal antibody that
binds to the HER2 receptor, in patients with metastatic androgen-independent
prostate cancer (AIPC). HER2 positivity was not required because safety was the
primary endpoint. Patients received oral estramustine 280 mg three times daily
(days 1 to 5); docetaxel, 70 mg/m(2) intravenously (day 2); and trastuzumab, 2
mg/kg intravenously (days 2, 9, and 19), every 21 days until the disease
progressed or toxicity became unacceptable. This regimen was well tolerated
among the first 13 treated patients. Grade 4 neutropenia was seen in 10% of
administered cycles. There were two episodes of febrile neutropenia and two
thrombembolic events. Of the 13 patients evaluable for prostate-specific antigen
(PSA) response, nine (69%) experienced a decrease in PSA level of >50%. Two
(33%) of six patients with measurable disease had objective responses, and one
complete response was seen on bone scan. Docetaxel/estramustine/trastuzumab
appears to be a safe combination when used in the treatment of metastatic AIPC.
The response data are too preliminary for speculation about the relative
benefits of this 3-drug regimen compared with the combination of only docetaxel
and estramustine in this clinical setting. BACKGROUND: Overexpression of the HER-2/neu oncoprotein has been reported to
occur in </= 60% of patients with prostate carcinoma and to correlate with
shortened survival. Trastuzumab is a humanized monoclonal antibody to the HER-2
receptor and has activity against HER-2-positive breast carcinoma, more so when
combined with a taxane. The authors screened for HER-2 overexpression in
patients developing hormone-refractory prostate carcinoma (HRPC) and conducted a
Phase II trial of trastuzumab plus docetaxel in HER-2-positive patients.
METHODS: Paraffin-embedded tumor specimens from potentially eligible patients
were screened for HER-2 expression by immunohistochemistry (IHC) and/or
amplification by fluorescent in situ hybridization (FISH). Shed HER-2 was also
assessed by enzyme-linked immunoradsorbent assay (ELISA). Patients with
HER-2-positive tumor specimens (IHC 2+ or 3+ or FISH ratio > 2) were initially
randomized to receive either single-agent trastuzumab or docetaxel. After two
treatment cycles, nonresponding patients received the trastuzumab/docetaxel
combination. Treatment was comprised of 30 mg/m(2) of docetaxel weekly for 6
weeks followed by a 2-week break and 4 mg/kg of trastuzumab intravenously during
Week 1 then 2 mg/kg per week thereafter. The cycle length was 8 weeks.
RESULTS: One hundred patients with HPRC were screened. IHC results were as
follows: 3+ (n = 1), 2+ (n = 6), 1+ (n = 26), 0 (n = 39), and insufficient
tissue specimen/not tested (n = 28). Only 3 of 37 patients had elevated shed
HER-2 by ELISA (> 15 mg/mL). None overexpressed HER-2 by IHC. FISH amplification
was found in 0 of 34 tissue samples. Of seven patients with IHC 3+ or 2+, four
were tested by ELISA and two by FISH. None were abnormal. Age and Gleason score
did not correlate with IHC status. Of the seven patients eligible for the Phase
II study, only four agreed to participate. The trial was thus closed for
nonfeasibility (the overall HER-2 positivity rate was < 20%). No patient
responded to trastuzumab alone. The median survival was not reached and the
median progression-free survival was 7 months.
CONCLUSIONS: HER-2 overexpression by IHC in archival prostate carcinoma
specimens was infrequent. There was no apparent correlation among IHC, ELISA,
and FISH, although the sample size was limited. Conclusions regarding the
predictive value of HER-2 status on outcome after trastuzumab-based therapy were
not reached and were only drawn after larger-scale screening efforts. The
authors estimated that 1000 patients need to be screened to complete accrual to
a 40-patient efficacy trial. PURPOSE: To investigate the efficacy and toxicity of the antibody to the
HER-2/neu receptor (trastuzumab, Herceptin) in the treatment of advanced
hormone-refractory prostate cancer (HRPC).
MATERIALS AND METHODS: Eighteen patients with HRPC were recruited for this phase
II trial in which they received trastuzumab for 12 weeks or until disease
progression or unacceptable toxicity was documented. HER-2 receptor
overexpression was evaluated using immunohistochemistry (IHC) and dual-color
fluorescence in-situ hybridization (FISH) assays.
RESULTS: Trastuzumab as a single agent demonstrated little efficacy in treating
HRPC. Two patients demonstrated stable disease based on a decrease in PSA level
to less than 50% of baseline. No patient demonstrated a regression of
radiographic bony or soft tissue metastatic disease. The medication was well
tolerated in 16 patients (89%), and 2 patients (11%) had to be hospitalized for
cardiac complications.
CONCLUSIONS: Trastuzumab (Herceptin) as a single agent demonstrated poor
efficacy in treating HRPC. Based on promising results in treating breast cancer
with regimens using Herceptin and cytotoxic agents, a similar combination
approach might demonstrate better efficacy in treating HRPC. New drugs and new combinations of drugs have recently shown promising clinical
activity in hormone refractory prostate cancer. We studied the association of
gefitinib with trastuzumab on the androgen-refractory prostate cancer cell line
DU145 expressing both epidermal growth factor receptor (EGFR) and HER-2. Drug
combinations with radiotherapy (RT) were considered along with the analysis of
factors linked to cell proliferation and apoptosis. The antitumour effects of
gefitinib were more pronounced than those observed with trastuzumab. In mice
receiving the gefitinib-trastuzumab combination, reduction in tumour volume was
inferior to that predicted by the observed impact of the agents alone. The
presence of trastuzumab markedly attenuated the relative increase on p27
expression and the Bax:Bcl2 ratio induced by gefitinib. The combination
gefitinib-RT had similar antitumour effects as those predicted by the impact of
the individual treatments, whereas the effect of the trastuzumab-RT combination
was inferior to that predicted by the individual effects. The present data
should be borne in mind when designing new clinical schedules for treatment of
hormone-refractory prostate cancer including the use of HER inhibitors. The human epidermal growth factor receptor (HER) family of receptor tyrosine
kinases is part of a network of pathways that are involved in the development
and progression of prostate cancer. HER-kinase receptors include epidermal
growth factor receptor (EGFR), HER2, HER3, and HER4, which must combine as
dimers to affect signaling. Different combinations of receptors produce
different qualities and levels of pathway activation. Among HER-family
receptors, HER2 activation is particularly important in breast cancer, as HER2
gene amplification is associated with a distinct clinical course and response to
treatment with a HER2-directed therapy (trastuzumab). Although HER2 can be
over-expressed in prostate cancer, there is no clinical data to support the use
of trastuzumab for prostate cancer patients. Preclinical and clinical data show
that the activation of the HER-kinase axis is important for the progression of
prostate cancer to androgen-independent disease. Data points towards the
importance of inhibiting multiple members of the HER-kinase family to achieve
more complete blockade of this axis for cancers other than HER2-overexpressing
breast cancer. Multiple pharmaceutical agents that block the HER-kinase axis are
currently being tested for patients with prostate cancer. These include
antibodies, tyrosine kinase inhibitors, and novel strategies which seek to
decrease HER2 expression. Present management of metastatic prostate cancer, which includes hormonal
therapy, chemotherapy, and radiotherapy, are frequently palliative. Taxanes, and
specifically docetaxel, are being extensively investigated to improve the
survival of metastatic prostate cancer patients. Although paclitaxel exhibits a
wide spectrum of antitumor activity, its therapeutic application is limited, in
part, due to its low water solubility that necessitates the use of Cremophor EL,
which is known to induce hypersensitivity reactions. Therefore, the objective of
this present study was to assess the efficiency of paclitaxel palmitate-loaded
anti-HER2 immunoemulsions, a targeted drug delivery system based on cationic
emulsion covalently linked to anti-HER2 monoclonal antibody (Herceptin), in a
well-established in vivo pharmacologic model of metastatic prostate cancer that
overexpresses the HER2 receptor. It was clearly noted that the cationic emulsion
and immunoemulsion did not activate the complement compared with the commercial
and paclitaxel palmitate hydroalcoholic formulations. In addition, 10 mg/kg of
paclitaxel palmitate-loaded immunoemulsion once weekly over 3 weeks inhibits the
tumor growth in severe combined immunodeficient mice much more than the cationic
emulsion (P < 0.05) and the paclitaxel palmitate formulation (P < 0.01). The
histopathologic analysis suggested a therapeutic improvement trend in favor of
the immunoemulsion. However, there was no significant difference in
antimetastatic activity between the emulsion and the immunoemulsion despite the
affinity of the immunoemulsion towards the HER2 receptor. Although the tumor
growth was not fully inhibited, the actual results are encouraging and may lead
to an improved therapeutic strategy of metastatic prostate cancer treatment. Antitumour activity of docetaxel (Taxotere) in hormone-dependent (HD) and
hormone-independent (HID) prostate cancer PAC120 xenograft model was previously
reported, and its level was associated with HER2 protein expression. In the
present study, we evaluate the antitumour effects of docetaxel combined with
trastuzumab (Herceptin), an anti-HER2 antibody. Although trastuzumab alone had
no effect on tumour growth, it potentiated the antitumour activity of docetaxel
in HD tumours and more strongly in HID variants. Using the HID28 variant, we
show that docetaxel treatment of tumour-bearing mice induces an increased HER2
mRNA expression of the tyrosine kinase receptor of 25-fold 24 h after docetaxel
treatment, while HER2 protein and p-AKT decreased. This was followed by an
increase of HER2 protein 3 days (two-fold) after docetaxel treatment and by a
strong HER2 release in the serum of treated mice; expression of phospho-ERK,
p27, BCL2 and HSP70 concomitantly increased. Similar molecular alterations were
induced by docetaxel plus trastuzumab combination, except for that there was a
transient and complete disappearance of AR and HSP90 proteins 24 h after
treatment. We show that in addition to its known effects on tubulin and mitotic
spindles, docetaxel induces complex signalisation pathway mechanisms in
surviving cells, including HER2, which can be pharmacologically targeted. This
study suggests that the docetaxel/trastuzumab combination may prove an effective
therapeutic approach for HER2-expressing hormone-refractory prostate cancer. BACKGROUND/AIMS: Evaluation of Her2/neu expression in the peripheral blood
mononuclear cell fraction of prostate cancer patients by RT-PCR may afford an
opportunity for the detection of circulating tumor cells and thus serve as a
marker of micrometastatic disease.
METHODS: We studied Her2/neu expression by reverse transcriptase-polymerase
chain reaction in peripheral blood mononuclear cell fraction samples of 21
controls and serially in 43 patients with prostate cancer.
RESULTS: None of the 21 controls expressed Her2/neu whereas 23.25% (95% CI,
11.75-38.63) of the patients were positive at entry into the study, and 65.11%
(95% CI, 49.07-78.99) of them had at least one positive result during the
follow-up period. Her2/neu positivity at study entry did not correlate
significantly with PSA level, Gleason score, clinical stage or time to PSA
progression. When we analyzed only patients with advanced disease, we observed a
trend towards a shorter time to PSA progression in patients with at least one
positive Her2/neu result during the follow-up (log-rank test, P = 0.08).
CONCLUSIONS: We conclude that Her2/neu expression in the peripheral blood
mononuclear cell fraction of prostate cancer patients is frequent and therefore
this assay may potentially be useful to detect the presence of micrometastatic
disease in men with prostate cancer and for monitoring patients enrolled in
trastuzumab-based therapeutic protocols. The potential of the HER2-targeting antibody trastuzumab as a
radioimmunoconjugate useful for both imaging and therapy was investigated.
Conjugation of trastuzumab with the acyclic bifunctional chelator CHX-A"-DTPA
yielded a chelate:protein ratio of 3.4 ± 0.3; the immunoreactivity of the
antibody unaffected. Radiolabeling was efficient, routinely yielding a product
with high specific activity. Tumor targeting was evaluated in mice bearing
subcutaneous (s.c.) xenografts of colorectal, pancreatic, ovarian, and prostate
carcinomas. High uptake of the radioimmunoconjugate, injected intravenously
(i.v.), was observed in each of the models, and the highest tumor %ID/g (51.18 ±
13.58) was obtained with the ovarian (SKOV-3) tumor xenograft. Specificity was
demonstrated by the absence of uptake of 111In-trastuzumab by melanoma (A375)
s.c. xenografts and 111In-HuIgG by s.c. LS-174T xenografts. Minimal uptake of
i.v. injected 111In-trastuzumab in normal organs was confirmed in
non-tumor-bearing mice. The in vivo behavior of 111In-trastuzumab in mice
bearing intraperitoneal (i.p.) LS-174T tumors resulted in a tumor %ID/g of
130.85 ± 273.34 at 24 h. Visualization of tumor, s.c. and i.p. xenografts, was
achieved by γ-scintigraphy and PET imaging. Blood pool was evident as expected,
but cleared over time. The blood pharmacokinetics of i.v. and i.p. injected
111In-trastuzumab was determined in mice with and without tumors. The data from
these in vitro and in vivo studies supported advancement of radiolabeled
trastuzumab into two clinical studies, a Phase 0 imaging study in the Molecular
Imaging Program of the National Cancer Institute and a Phase 1
radioimmunotherapy study at the University of Alabama. The type I receptor tyrosine kinases (RTKs) are involved in various aspects of
cell growth, survival, and differentiation. Among the known RTKs, the epidermal
growth factor receptor (EGFR) and ErbB-2 (HER-2) are two widely studied proteins
that are prototypic members of the ErbB family which also includes ErbB-3
(Her-3) and ErbB-4 (Her-4). Overexpression of ErbB-2 and EGFR has been
associated with aggressive disease and poor patient prognosis in a range of
human tumour types (e.g. breast, lung, ovarian, prostate, and squamous carcinoma
of head and neck). Disruption of signal transduction of these kinases has been
shown to have an antiproliferative effect. Various approaches have been
developed to target the ErbB signalling pathways including monoclonal antibodies
(trastuzumab/Herceptin™ and cetuximab/Erbitux™) directed against the receptor,
and synthetic tyrosine kinase inhibitors (gefitinib/Iressa™ and
erlotinib/Tarceva™). Since many tumours overexpress ErbB receptors, simultaneous
targeting of multiple ErbB receptors therefore becomes a promising approach to
cancer treatment. Lapatinib (Tykerb™), a potent dual EGFR/ErbB-2 inhibitor, was
approved for the treatment of ErbB-2-positive breast cancer. Despite years of
intensive research on EGFR inhibitors, there is a surprising dearth of
chemically distinct small inhibitors with a high degree of selectivity. There is
also a need for new scaffolds due to the recent finding of EGFR mutations which
render the kinase resistant to gefinitib and erlotinib. The structures under
study will be quinazolines with different substituents. The structure-activity
relationships and biological evaluation of compounds published during the last
four years will be reviewed herein. PURPOSE: Patients with recurrent prostate cancer are commonly treated with
androgen withdrawal therapy (AWT); however, almost all patients eventually
progress to castration resistant prostate cancer (CRPC), indicating failure of
AWT to eliminate androgen-sensitive prostate cancer. The overall goal of these
studies is to determine whether dual inhibition of the receptor tyrosine kinases
epidermal growth factor receptor (EGFR) and HER2 would prolong the effectiveness
of this treatment in prostate cancer.
EXPERIMENTAL DESIGN: We used androgen-dependent LNCaP cells and its CRPC
sublines LNCaP-AI and C4-2. Additional data were collected in pRNS-1-1 cells
stably expressing a mutant androgen receptor (AR-T877A), and in nude mice
harboring CWR22 tumors. Studies utilized EGFR inhibitors erlotinib and AG1478,
and HER2 inhibitors trastuzumab and AG879.
RESULTS: Dual EGFR/HER2 inhibition induced apoptosis selectively in
androgen-sensitive prostate cancer cells undergoing AWT, but not in the presence
of androgens, or in CRPC cells. We show that AWT alone failed to induce
significant apoptosis in androgen-dependent cells, due to AWT-induced increase
in HER2 and ErbB3, which promoted survival by increasing Akt phosphorylation.
AWT-induced ErbB3 stabilized the AR and stimulated PSA, while it was inactivated
only by inhibition of both its dimerization partners EGFR and HER2 (prostate
cancer cells do not express ErbB4); but not the inhibition of any one receptor
alone, explaining the success of dual EGFR/HER2 inhibition in sensitizing
androgen-dependent cells to AWT. The effectiveness of the inhibitors in
suppressing growth correlated with its ability to prevent Akt phosphorylation.
CONCLUSION: These studies indicate that dual EGFR/HER2 inhibition, administered
together with AWT, sensitize prostate cancer cells to apoptosis during AWT. The purpose of this study was to determine therapeutic effects and systemic
toxicity of 212Pb-trastuzumab in an orthotopic model of human prostate cancer
cells in nude mice. TCMC-Trastuzumab was radiolabeled with 212Pb. The
212Pb-trastuzumab generated from the procedure was intact and had high binding
affinity with a dissociation constant (of 3.9±0.99 nM. PC-3MM2 cells, which
expressed a lower level of HER2 both in culture and in tumors, were used in
therapy studies. A single intravenous injection of 212Pb-trastuzumab reduced
tumor growth by 60-80%, reduced aortic lymph node metastasis, and prolonged the
survival of tumor-bearing mice. Treatment with 212Pb-trastuzumab did not cause
significant changes in body weight, serum glutamic pyruvic transaminase (SGPT),
blood urea nitrogen (BUN), hematological profiles, and histological morphology
of several major organs of tumor-bearing mice. These findings suggest that a
systemic delivery of 212Pb-trastuzumab could be an effective modality for
management of advanced human prostate cancer. The treatment of disseminated prostate cancer remains a great challenge in
current oncology practice. The proliferation of prostate cancer cells is
testosterone-driven, but clonal selection during androgen deprivation therapy
promotes the development of androgen-independent (hormone-refractory) cells,
which become phenotypically domit. Human epidermal growth factor receptor
type 2 (HER2) is capable of activating the androgen receptor pathway, even in
the absence of the ligand. The detection of phenotypic changes associated with
the development of androgen independence may influence patient management,
suggesting the initiation of a second-line therapy. This study aimed to
establish the level of HER2 expression in a number of prostate cancer cell lines
(LNCaP, PC3 and DU145) in order that they be used as models in further studies,
and to evaluate the binding and cellular processing of [(111)In]-labeled
trastuzumab and the anti-HER2 synthetic Affibody molecule ABY-025 in these cell
lines. The expression of HER2 was demonstrated and quantified in all three
tested prostate cancer cell-lines. Studies on cellular processing demonstrated
that internalization of both conjugates increased continuously during the whole
incubation. The internalization rate was approximately equal for both monoclonal
antibodies and Affibody molecules. In both cases, internalization was moderately
rapid. Such features would definitely favor the use of radiometal labels for
trastuzumab and, most likely, for affibody molecules. The level of HER2
expression in these cell lines is sufficient for in vivo molecular imaging. The epidermal growth factor receptor (EGFR) family members are potential targets
for therapy using extra-cellular domain receptor binding agents, such as the
antibodies trastuzumab and cetuximab, or antibodies labeled with therapeutically
useful radionuclides or toxins. This is especially the case when the tumor cells
are resistant to chemotherapy and tyrosine kinase inhibitors. Studies concerning
the expression of these receptors in prostate cancer vary in the literature,
possibly due to differences in patient inclusion, sample preparations and
scoring criteria. In our study, EGFR, HER2 and HER3 expression was analyzed in
prostate cancer samples from primary tumors and corresponding lymph node
metastases from 12 patients. The expression of HER2 and EGFR was scored from
immunohistochemical preparations and the HercepTest criteria (0, 1+, 2+ or 3+),
while HER3 expression was scored as no, weak or strong staining. There were 5
EGFR-positive (2+ or 3+) primary tumors and 6 EGFR-positive lymph node
metastases, and there was EGFR upregulation in one metastasis. Only 4 of the 12
patients had marked HER2 expression (2+ or 3+) in their primary tumors and there
was one downregulation and 5 cases of upregulation in the metastases. Thus, a
total of 8 out of 12 analyzed metastases were HER2-positive. Of the 12 primary
tumors, 9 expressed HER3 while only 2 of the lymph node metastases expressed
recognizable HER3 staining, so 7 metastases appeared to have downregulated HER3
expression. In one of the primary tumors there was positive co-expression of
EGFR and HER2, while this co-expression was observed in 4 of the metastases.
Thus, there were tendencies for upregulation of HER2, increased co-expression of
EGFR and HER2 and downregulation of HER3 in the prostate cancer lymph node
metastases in comparison to the primary tumors. The results are encouraging for
studies involving more patients. Possible strategies for EGFR- and HER2-targeted
therapy are briefly discussed in the present study, especially with regard to
the expression and co-expression of EGFR and HER2 in metastases. |
Which are the Yamanaka factors? | The Yamanaka factors are the OCT4, SOX2, MYC, and KLF4 transcription factors | Yamanaka factors (Oct3/4, Sox2, Klf4, c-Myc) are highly expressed in embryonic
stem (ES) cells, and their over-expression can induce pluripotency in both mouse
and human somatic cells, indicating that these factors regulate the
developmental signaling network necessary for ES cell pluripotency. However,
systemic analysis of the signaling pathways regulated by Yamanaka factors has
not yet been fully described. In this study, we identified the target promoters
of endogenous Yamanaka factors on a whole genome scale using ChIP (chromatin
immunoprecipitation)-on-chip in E14.1 mouse ES cells, and we found that these
four factors co-occupied 58 promoters. Interestingly, when Oct4 and Sox2 were
analyzed as core factors, Klf4 functioned to enhance the core factors for
development regulation, whereas c-Myc seemed to play a distinct role in
regulating metabolism. The pathway analysis revealed that Yamanaka factors
collectively regulate a developmental signaling network composed of 16
developmental signaling pathways, nine of which represent earlier unknown
pathways in ES cells, including apoptosis and cell-cycle pathways. We further
analyzed data from a recent study examining Yamanaka factors in mouse ES cells.
Interestingly, this analysis also revealed 16 developmental signaling pathways,
of which 14 pathways overlap with the ones revealed by this study, despite that
the target genes and the signaling pathways regulated by each individual
Yamanaka factor differ significantly between these two datasets. We suggest that
Yamanaka factors critically regulate a developmental signaling network composed
of approximately a dozen crucial developmental signaling pathways to maintain
the pluripotency of ES cells and probably also to induce pluripotent stem cells. Ectopic expression of key reprogramming transgenes in somatic cells enables them
to adopt the characteristics of pluripotency. Such cells have been termed
induced pluripotent stem (iPS) cells and have revolutionized the field of
somatic cell reprogramming, as the need for embryonic material is obviated. One
of the issues facing both the clinical translation of iPS cell technology and
the efficient derivation of iPS cell lines in the research laboratory is
choosing the most appropriate somatic cell type for induction. In this study, we
demonstrate the direct reprogramming of a defined population of neural stem
cells (NSCs) derived from the subventricular zone (SVZ) and adipose
tissue-derived cells (ADCs) from adult mice using retroviral transduction of the
Yamanaka factors Oct4, Sox2, Klf4, and c-Myc, and compared the results obtained
with a mouse embryonic fibroblast (mEF) control. We isolated mEFs, NSCs, and
ADCs from transgenic mice, which possess a GFP transgene under control of the
Oct4 promoter, and validated GFP expression as an indicator of reprogramming.
While transduction efficiencies were not significantly different among the
different cell types (mEFs 68.70 +/- 2.62%, ADCs 70.61 +/- 15.4%, NSCs, 68.72
+/- 3%, p = 0.97), the number of GFP-positive colonies and hence the number of
reprogramming events was significantly higher for both NSCs (13.50 +/- 4.10
colonies, 0.13 +/- 0.06%) and ADCs (118.20 +/- 38.28 colonies, 1.14 +/- 0.77%)
when compared with the mEF control (3.17 +/- 0.29 colonies, 0.03 +/- 0.005%).
ADCs were most amenable to reprogramming with an 8- and 38-fold greater
reprogramming efficiency than NSCs and mEFs, respectively. Both NSC iPS and ADC
iPS cells were demonstrated to express markers of pluripotency and could
differentiate to the three germ layers, both in vitro and in vivo, to cells
representative of the three germ lineages. Our findings confirm that ADCs are an
ideal candidate as a readily accessible somatic cell type for high efficiency
establishment of iPS cell lines. Epidermal melanocytes play an important role in protecting the skin from UV
rays, and their functional impairment results in pigment disorders.
Additionally, melanomas are considered to arise from mutations that accumulate
in melanocyte stem cells. The mechanisms underlying melanocyte differentiation
and the defining characteristics of melanocyte stem cells in humans are,
however, largely unknown. In the present study, we set out to generate
melanocytes from human iPS cells in vitro, leading to a preliminary
investigation of the mechanisms of human melanocyte differentiation. We
generated iPS cell lines from human dermal fibroblasts using the Yamanaka
factors (SOX2, OCT3/4, and KLF4, with or without c-MYC). These iPS cell lines
were subsequently used to form embryoid bodies (EBs) and then differentiated
into melanocytes via culture supplementation with Wnt3a, SCF, and ET-3. Seven
weeks after inducing differentiation, pigmented cells expressing melanocyte
markers such as MITF, tyrosinase, SILV, and TYRP1, were detected. Melanosomes
were identified in these pigmented cells by electron microscopy, and global gene
expression profiling of the pigmented cells showed a high similarity to that of
human primary foreskin-derived melanocytes, suggesting the successful generation
of melanocytes from iPS cells. This in vitro differentiation system should prove
useful for understanding human melanocyte biology and revealing the mechanism of
various pigment cell disorders, including melanoma. Generation of induced pluripotent stem (iPS) cells from somatic cells has been
successfully achieved by ectopic expression of four transcription factors, Oct4,
Sox2, Klf4 and c-Myc, also known as the Yamanaka factors. In practice, initial
iPS colonies are picked based on their embryonic stem (ES) cell-like morphology,
but often may go on to fail subsequent assays, such as the alkaline phosphate
(AP) assay. In this study, we co-expressed through lenti-viral delivery the
Yamanaka factors in amniotic fluid-derived (AF) cells. ES-like colonies were
picked onto a traditional feeder layer and a high percentage AF-iPS with partial
to no AP activity was found. Interestingly, we obtained an overwhelming majority
of fully stained AP positive (AP+) AF-iPS colonies when colonies were first
seeded on a feeder-free culture system, and then transferred to a feeder layer
for expansion. Furthermore, colonies with no AP activity were not detected. This
screening step decreased the variation seen between morphology and AP assay. We
observed the AF-iPS colonies grown on the feeder layer with 28% AP+ colonies,
45% AP partially positive (AP+/-) colonies and 27% AP negative (AP-) colonies,
while colonies screened by the feeder-free system were 84% AP+ colonies, 16%
AP+/- colonies and no AP- colonies. The feeder-free screened AP+ AF-iPS colonies
were also positive for pluripotent markers, OCT4, SOX2, NANOG, TRA-1-60,
TRA-1-81, SSEA-3 and SSEA-4 as well as having differentiation abilities into
three germ layers in vitro and in vivo. In this study, we report a simplistic,
one-step method for selection of AP+ AF-iPS cells via feeder-free screening. Induced pluripotent stem (iPS) cells can be obtained from terminally
differentiated somatic cells by overexpression of defined sets of reprogramming
transcription factors. These protein sets have been called the Yamanaka factors,
namely Sox2, Oct3/4 (Pou5f1), Klf4, and c-Myc, and the Thomson factors, namely
Sox2, Oct3, Lin28, and Nanog. Other sets of proteins, while not essential for
the formation of iPS cells, are important for improving the efficiency of the
induction and still other sets of proteins are important as markers for
embryonic stem cells. Structural information about most of these important
proteins is very sparse. Our bioinformatics analysis herein reveals that these
reprogramming factors and most of the efficiency-improving and embryonic stem
cell markers are highly enriched in intrinsic disorder. As is typical for
transcription factors, these proteins are modular. Specific sites for
interaction with other proteins and DNA are dispersed in the long regions of
intrinsic disorder. These highly dynamic interaction sites are evidently
responsible for the delicate interplay among various molecules. The
bioinformatics analysis given herein should facilitate the investigation of the
roles and organization of these modular interaction sites, thereby helping to
shed further light on the pathways that underlie the mechanism(s) by which
terminally differentiated cells are converted to iPS cells. Human induced pluripotent stem cells (iPSCs) have become an intriguing approach
for neurological disease modeling, because neural lineage-specific cell types
that retain the donors' complex genetics can be established in vitro. The
statistical power of these iPSC-based models, however, is dependent on accurate
diagnoses of the somatic cell donors; unfortunately, many neurodegenerative
diseases are commonly misdiagnosed in live human subjects. Postmortem
histopathological examination of a donor's brain, combined with premortem
clinical criteria, is often the most robust approach to correctly classify an
individual as a disease-specific case or unaffected control. In this study, we
describe iPSCs generated from a skin biopsy collected postmortem during the
rapid autopsy of a 75-year-old male, whole body donor, defined as an unaffected
neurological control by both clinical and histopathological criteria. These
iPSCs were established in a feeder-free system by lentiviral transduction of the
Yamanaka factors, Oct3/4, Sox2, Klf4, and c-Myc. Selected iPSC clones expressed
both nuclear and surface antigens recognized as pluripotency markers of human
embryonic stem cells (hESCs) and were able to differentiate in vitro into
neurons and glia. Statistical analysis also demonstrated that fibroblast
proliferation was significantly affected by biopsy site, but not donor age
(within an elderly cohort). These results provide evidence that autopsy
donor-derived fibroblasts can be successfully reprogrammed into iPSCs, and may
provide an advantageous approach for generating iPSC-based neurological disease
models. Induced pluripotent stem (iPS) cells have the potential to become a universal
resource for cell-based therapies in regenerative medicine; however, prior to
the use of such iPS cell-based therapies, preclinical assessment of their safety
and efficacy is essential. Non-human primates serve as valuable animal models
for human diseases or biomedical research; therefore, in this study, we
generated cynomolgus monkey iPS cells from adult skin and fetal fibroblast cells
by the retrovirally mediated introduction of four human transcription factors:
c-Myc, Klf4, Oct3/4, and Sox2 (the so-called "Yamanaka factors"). Twenty to
30 days after the introduction of these factors, several cynomolgus monkey
embryonic stem (ES) cell-like colonies appeared on SNL and mouse embryonic
fibroblast (MEF) feeder layers. These colonies were picked and cultivated in
primate ES medium. Seven iPS cell lines were established, and we detected the
expression of pluripotent markers that are also expressed in ES cells. Reverse
transcription polymerase chain reaction (PCR) showed that these iPS cells
expressed endogenous c-Myc, Klf4, Oct3/4, and Sox2 genes, whereas several
transgenes were silenced. Embryoid body and teratoma formation showed that the
cynomolgus iPS cells had the developmental potential to differentiate into cells
of all three primary germ layers. In summary, we generated cynomolgus monkey iPS
cells by retrovirus-mediated transduction of the human transcription factors,
c-Myc, Klf4, Oct3/4, and Sox2 into adult cynomolgus monkey skin cells and fetal
fibroblasts. The cynomolgus monkey is the most relevant primate model for human
disease, and the highly efficient generation of monkey iPS cells would allow
investigation of the treatments of various diseases in this model via
therapeutic cloning. Germ cell tumors (GCTs) are unique in that they exhibit diverse biological
characteristics and pathological features. Although several in vivo GCT models
are available, studies on GCTs are hampered because in vivo development of GCTs
is time consuming and prevents a detailed molecular analysis of the
transformation process. Here we developed a novel strategy to transform mouse
testis cells in vitro. Lentivirus-mediated transfection of domit negative
Trp53, Myc, and activated Hras1 into a CD9-expressing testis cells caused
tumorigenic conversion in vitro. Although these cells resembled embryonic stem
(ES) cells, they were aneuploid and lacked Nanog expression, which is involved
in the maintece of the undifferentiated state in ES cells. Euploid ES-like
cells were produced by transfecting the Yamanaka factors (Pou5f1, Myc, Klf4, and
Sox2) into the same cell population. Although these cells expressed Nanog, they
were distinct from ES cells in that they expressed CD44, a cancer stem cell
antigen. Both treatments induced similar changes in the DNA methylation patterns
in differentially methylated regions of imprinted genes. Moreover, despite the
differences in their phenotype and karyotype, both cell types similarly produced
mixed GCTs on transplantation, which were composed of teratomas, seminomas, and
embryonal carcinomas. Thus, in vitro testis cell transformation facilitates an
analysis of the GCT formation process, and our results also suggest the close
similarity between GCT formation and reprogramming. BACKGROUND: Recent studies have found that p53 and its' associated cell cycle
pathways are major inhibitors of human induced pluripotent stem (iPS) cell
generation. In the same family as p53 is p73, which shares sequence similarities
with p53. However, p73 also has distinct properties of its own, such as two
alternative promoters to express transactivation of p73 (TAp73) and N terminal
deleted p73 (DNp73). Functionally, TAp73 acts similarly to p53 in tumor
suppression. However, DNp73, on the other hand acts as an oncogene to suppress
p53 and p73 induced apoptosis. Therefore, how can p73 have opposing roles in
human iPS cell generation?
RESULTS: Transcription factors, Oct4, Sox2, Klf4 and cMyc (4TF, Yamanaka
factors) are used as basal conditions to generate iPS cells. In addition, the
factor of DNp73(actually alpha splicing DNp73, DNp73α) is used to generate iPS
cells. The experiment found that the addition of DNp73 gene increases human iPS
cell generation efficiency by 12.6 folds in comparison to human fibroblast cells
transduced with only the basal conditions. Also, iPS cells generated with DNp73
expression are more resistant to in vitro and in vivo differentiation.
CONCLUSIONS: This study found DNp73, a family member of p53, is also involved in
the human iPS cell generation. Specifically, that the involvement of DNp73
generates iPS cells that are more resistant to in vitro and in vivo
differentiation. Therefore, this data may prove to be useful in future
developmental studies and cancer researches. Induced pluripotent stem (iPS) cells were originally generated from mouse
fibroblasts by enforced expression of Yamanaka factors (Oct3/4, Sox2, Klf4, and
c-Myc). The technique was quickly reproduced with human fibroblasts or
mesenchymal stem cells. Although having been showed therapeutic potential in
animal models of sickle cell anemia and Parkinson's disease, iPS cells generated
by viral methods do not suit all the clinical applications. Various non-viral
methods have appeared in recent years for application of iPS cells in cell
transplantation therapy. These methods mainly include DNA vector-based
approaches, transfection of mRNA, and transduction of reprogramming proteins.
This review summarized these non-viral methods and compare the advantages,
disadvantages, efficiency, and safety of these methods. Signal transducer and activator of transcription (STAT) 3, a member of a family
of DNA-binding molecules, is a potential target in the treatment of cancer. The
highly phosphorylated STAT3 in cancer cells contributes to numerous
physiological and oncogenic signaling pathways. Furthermore, a significant
association between STAT3 signaling and glioblastoma multiforme stem-like cell
(GBM-SC) development and maintece has been demonstrated in recent studies.
Previously, we reported a novel small molecule inhibitor of STAT3 dimerization,
STX-0119, as a cancer therapeutic. In the present study, we focused on cancer
stem-like cells derived from recurrent GBM patients and investigated the
efficacy of STX-0119. Three GBM stem cell lines showed many stem cell markers
such as CD133, EGFR, Nanog, Olig2, nestin and Yamanaka factors (c-myc, KLF4,
Oct3/4 and SOX2) compared with parental cell lines. These cell lines also formed
tumors in vivo and had similar histological to surgically resected tumors. STAT3
phosphorylation was activated more in the GBM-SC lines than serum-derived GB
cell lines. The growth inhibitory effect of STX-0119 on GBM-SCs was moderate
(IC50 15-44 µM) and stronger compared to that of WP1066 in two cell lines. On
the other hand, the effect of temozolomide was weak in all the cell lines (IC50
53-226 µM). Notably, STX-0119 demonstrated strong inhibition of the expression
of STAT3 target genes (c-myc, survivin, cyclin D1, HIF-1α and VEGF) and stem
cell-associated genes (CD44, Nanog, nestin and CD133) as well as the induction
of apoptosis in one stem-like cell line. Interestingly, VEGFR2 mRNA was also
remarkably inhibited by STX-0119. In a model using transplantable stem-like cell
lines in vivo GB-SCC010 and 026, STX-0119 inhibited the growth of GBM-SCs at 80
mg/kg. STX-0119, an inhibitor of STAT3, may serve as a novel therapeutic
compound against GBM-SCs even in temozolomide-resistant GBM patients and has the
potential for GBM-SC-specific therapeutics in combination with temozolomide plus
radiation therapy. CytoTune™-iPS Reprogramming System uses vectors based on replication in
competent Sendai virus (SeV) to safely and effectively deliver and express key
genetic factors necessary for reprogramming somatic cells into iPSCs. In
contrast to many available protocols, which rely on viral vectors that integrate
into the genome of the host cell, the CytoTune™ Reprogramming System uses
vectors that are non-integrating and remain in the cytoplasm (i.e., they are
zero-footprint). In addition, the host cell can be cleared of the vectors and
reprogramming factor genes by exploiting the cytoplasmic nature of SeV and the
functional temperature sensitivity mutations introduced into the key viral
proteins. The CytoTune™-iPS Reprogramming Kit contains four SeV-based
reprogramming vectors, each capable of expressing one of the four Yamanaka
factors (i.e., Oct4, Sox2, Klf4, and c-Myc) and are optimized for generating
iPSCs from human somatic cells. The reprogramming vectors in this kit have been
engineered to increase biological and environmental safety. The recently established reprogramming of somatic cells into induced pluripotent
stem cells (iPSCs) by Takahashi and Yamanaka represents a valuable tool for
future therapeutic applications. To date, the mechanisms underlying this process
are still largely unknown. In particular, the mechanisms how the Yamanaka
factors (Oct4, Sox2, Klf4, and c-Myc) directly drive reprogramming and which
additional components are involved are still not yet understood. In this study,
we aimed at analyzing the role of ADP-ribosyltransferase diphtheria toxin-like
one (Artd1; formerly called poly(ADP-ribose) polymerase 1 [Parp1]) during
reprogramming. We found that poly(ADP-ribosylation) (PARylation) of the
reprogramming factor Sox2 by Artd1 plays an important role during the first days
upon transduction with the reprogramming factors. A process that happens before
Artd1 in conjunction with 10-11 translocation-2 (Tet2) mediates the histone
modifications necessary for the establishment of an activated chromatin state at
pluripotency loci (e.g., Nanog and Essrb) [Nature 2012;488:652-655]. Wild-type
(WT) fibroblasts treated with an Artd1 inhibitor as well as fibroblasts
deficient for Artd1 (Artd1-/-) show strongly decreased reprogramming capacity.
Our data indicate that Artd1-mediated PARylation of Sox2 favors its binding to
the fibroblast growth factor 4 (Fgf4) enhancer, thereby activating Fgf4
expression. The importance of Fgf4 during the first 4 days upon initiation of
reprogramming was also highlighted by the observation that exogenous addition of
Fgf4 was sufficient to restore the reprogramming capacity of Artd1-/- fibroblast
to WT levels. In conclusion, our data clearly show that the interaction between
Artd1 and Sox2 is crucial for the first steps of the reprogramming process and
that early expression of Fgf4 (day 2 to day 4) is an essential component for the
successful generation of iPSCs. The 'Yamanaka factors' (Oct4, Sox2, Klf4 and c-Myc) are able to generate induced
pluripotent stem (iPS) cells from different cell types. However, to what degree
primary maligt cells can be reprogrammed into a pluripotent state has not
been vigorously assessed. We established an acute myeloid leukemia (AML) model
by overexpressing the human mixed-lineage leukemia-AF9 (MLL-AF9) fusion gene in
mouse hematopoietic cells that carry Yamanaka factors under the control of
doxycycline (Dox). On addition of Dox to the culture, the transplantable
leukemia cells were efficiently converted into iPS cells that could form
teratomas and produce chimeras. Interestingly, most chimeric mice spontaneously
developed the same type of AML. Moreover, both iPS reprogramming and leukemia
reinitiation paths could descend from the same leukemia-initiating cell. RNA-seq
analysis showed reversible global gene expression patterns between these
interchangeable leukemia and iPS cells on activation or reactivation of MLL-AF9,
suggesting a sufficient epigenetic force in driving the leukemogenic process.
This study represents an important step for further defining the potential
interplay between oncogenic molecules and reprogramming factors during MLL
leukemogenesis. More importantly, our reprogramming approach may be expanded to
characterize a range of hematopoietic maligcies in order to develop new
strategies for clinical diagnosis and treatment. |
What is the aim of the Human Chromosome-centric Proteome Project (C-HPP)? | The chromosome-centric human proteome project aims to systematically map all human proteins, chromosome by chromosome, in a gene-centric manner through dedicated efforts from national and international teams | The objective of the international Chromosome-Centric Human Proteome Project
(C-HPP) is to map and annotate all proteins encoded by the genes on each human
chromosome. The C-HPP consortium was established to organize a collaborative
network among the research teams responsible for protein mapping of individual
chromosomes and to identify compelling biological and genetic mechanisms
influencing colocated genes and their protein products. The C-HPP aims to foster
the development of proteome analysis and integration of the findings from
related molecular -omics technology platforms through collaborations among
universities, industries, and private research groups. The C-HPP consortium
leadership has elicited broad input for standard guidelines to manage these
international efforts more efficiently by mobilizing existing resources and
collaborative networks. The C-HPP guidelines set out the collaborative consensus
of the C-HPP teams, introduce topics associated with experimental approaches,
data production, quality control, treatment, and transparency of data,
goverce of the consortium, and collaborative benefits. A companion approach
for the Biology and Disease-Driven HPP (B/D-HPP) component of the Human Proteome
Project is currently being organized, building upon the Human Proteome
Organization's organ-based and biofluid-based initiatives
(www.hupo.org/research). The common application of these guidelines in the
participating laboratories is expected to facilitate the goal of a comprehensive
analysis of the human proteome. The goal of the Human Proteome Project (HPP) is to fully characterize the 21,000
human protein-coding genes with respect to the estimated two million proteins
they encode. As such, the HPP aims to create a comprehensive, detailed resource
to help elucidate protein functions and to advance medical treatment. Similarly
to the Human Genome Project (HGP), the HPP chose a chromosome-centric approach,
assigning different chromosomes to different countries. Here we introduce a
scoring method for chromosome ranking based on several characteristics,
including relevance to health problems, existing published knowledge, and
current transcriptome and proteome coverage. The score of each chromosome was
computed as a weighted combination of indexes reflecting the aforementioned
characteristics. The approach is tailored to the chromosome-centric HPP (C-HPP),
and is advantageous in that it takes into account currently available
information. We ranked the human chromosomes using the proposed score, and
observed that Chr Y, Chr 13, and Chr 18 were top-ranked, whereas the scores of
Chr 19, Chr 11, and Chr 17 were comparatively low. For Chr 18, selected for the
Russian part of C-HPP, about 25% of the encoded genes were associated with
diseases, including cancers and neurodegenerative and psychiatric diseases, as
well as type 1 diabetes and essential hypertension. This ranking approach could
easily be adapted to prioritize research for other sets of genes, such as
metabolic pathways and functional categories. The Chromosome-centric Human Proteome Project (C-HPP) aims to define all
proteins encoded in each chromosome and especially to identify proteins that
currently lack evidence by mass spectrometry. The C-HPP also prioritizes
particular protein subsets such as membrane proteins, post-translational
modifications, and low-abundance proteins. In this study, we aimed to generate
deep profiling of the membrane proteins of human breast cancer tissues on a
chromosome-by-chromosome basis using shotgun proteomics. We identified 7092
unique proteins using membrane fractions isolated from pooled breast cancer
tissues with high confidence. A total of 3282 proteins were annotated as
membrane proteins by Gene Ontology analysis, which covered 45% of the membrane
proteins predicted in 20,859 protein-coding genes. Furthermore, we were able to
identify 851 membrane proteins that currently lack evidence by mass spectrometry
in neXtProt. Our results will contribute to the accomplishment of the primary
goal of the C-HPP in identifying so-called "missing proteins" and generating a
whole protein catalog for each chromosome. About 5000 (25%) of the ~20400 human protein-coding genes currently lack any
experimental evidence at the protein level. For many others, there is only
little information relative to their abundance, distribution, subcellular
localization, interactions, or cellular functions. The aim of the HUPO Human
Proteome Project (HPP, www.thehpp.org ) is to collect this information for every
human protein. HPP is based on three major pillars: mass spectrometry (MS),
antibody/affinity capture reagents (Ab), and bioinformatics-driven knowledge
base (KB). To meet this objective, the Chromosome-Centric Human Proteome Project
(C-HPP) proposes to build this catalog chromosome-by-chromosome ( www.c-hpp.org
) by focusing primarily on proteins that currently lack MS evidence or Ab
detection. These are termed "missing proteins" by the HPP consortium. The lack
of observation of a protein can be due to various factors including incorrect
and incomplete gene annotation, low or restricted expression, or instability.
neXtProt ( www.nextprot.org ) is a new web-based knowledge platform specific for
human proteins that aims to complement UniProtKB/Swiss-Prot ( www.uniprot.org )
with detailed information obtained from carefully selected high-throughput
experiments on genomic variation, post-translational modifications, as well as
protein expression in tissues and cells. This article describes how neXtProt
contributes to prioritize C-HPP efforts and integrates C-HPP results with other
research efforts to create a complete human proteome catalog. MALDI imaging mass spectrometry is a powerful tool for morphology-based
proteomic tissue analysis. However, peptide identification is still a major
challenge due to low S/N ratios, low mass accuracy and difficulties in
correlating observed m/z species with peptide identities. To address this, we
have analyzed tryptic digests of formalin-fixed paraffin-embedded tissue
microarray cores, from 31 ovarian cancer patients, by LC-MS/MS. The sample
preparation closely resembled the MALDI imaging workflow in order to create
representative reference data sets containing peptides also observable in MALDI
imaging experiments. This resulted in 3844 distinct peptide sequences, at a
false discovery rate of 1%, for the entire cohort and an average of 982 distinct
peptide sequences per sample. From this, a total of 840 proteins and, on
average, 297 proteins per sample could be inferred. To support the efforts of
the Chromosome-centric Human Proteome Project Consortium, we have annotated
these proteins with their respective chromosome location. In the presented work,
the benefit of using a large cohort of data sets was exemplified by correct
identification of several m/z species observed in a MALDI imaging experiment.
The tryptic peptide data sets generated will facilitate peptide identification
in future MALDI imaging studies on ovarian cancer. One of the major challenges of a chromosome-centric proteome project is to
explore in a systematic manner the potential proteins identified from the
chromosomal genome sequence, but not yet characterized on a protein level. Here,
we describe the use of RNA deep sequencing to screen human cell lines for RNA
profiles and to use this information to select cell lines suitable for
characterization of the corresponding gene product. In this manner, the
subcellular localization of proteins can be analyzed systematically using
antibody-based confocal microscopy. We demonstrate the usefulness of selecting
cell lines with high expression levels of RNA transcripts to increase the
likelihood of high quality immunofluorescence staining and subsequent successful
subcellular localization of the corresponding protein. The results show a path
to combine transcriptomics with affinity proteomics to characterize the proteins
in a gene- or chromosome-centric manner. The Chromosome 16 Consortium forms part of the Human Proteome Project that aims
to develop an entire map of the proteins encoded by the human genome following a
chromosome-centric strategy (C-HPP) to make progress in the understanding of
human biology in health and disease (B/D-HPP). A Spanish consortium of 16
laboratories was organized into five working groups: Protein/Antibody
microarrays, protein expression and Peptide Standard, S/MRM, Protein Sequencing,
Bioinformatics and Clinical healthcare, and Biobanking. The project is conceived
on a multicenter configuration, assuming the standards and integration
procedures already available in ProteoRed-ISCIII, which is encompassed within
HUPO initiatives. The products of the 870 protein coding genes in chromosome 16
were analyzed in Jurkat T lymphocyte cells, MCF-7 epithelial cells, and the
CCD18 fibroblast cell line as it is theoretically expected that most chromosome
16 protein coding genes are expressed in at least one of these. The
transcriptome and proteome of these cell lines was studied using gene expression
microarray and shotgun proteomics approaches, indicating an ample coverage of
chromosome 16. With regard to the B/D section, the main research areas have been
adopted and a biobanking initiative has been designed to optimize methods for
sample collection, management, and storage under normalized conditions and to
define QC standards. The general strategy of the Chr-16 HPP and the current
state of the different initiatives are discussed. A first research development progress report of the Chromosome 19 Consortium
with members from Sweden, Norway, Spain, United States, China and India, a part
of the Chromosome-centric Human Proteome Project (C-HPP) global initiative, is
presented ( http://www.c-hpp.org ). From the chromosome 19 peptide-targeted
library constituting 6159 peptides, a pilot study was conducted using a subset
with 125 isotope-labeled peptides. We applied an annotation strategy with triple
quadrupole, ESI-Qtrap, and MALDI mass spectrometry platforms, comparing the
quality of data within and in between these instrumental set-ups. LC-MS
conditions were outlined by multiplex assay developments, followed by MRM assay
developments. SRM was applied to biobank samples, quantifying kallikrein 3
(prostate specific antigen) in plasma from prostate cancer patients. The
antibody production has been initiated for more than 1200 genes from the entire
chromosome 19, and the progress developments are presented. We developed a
dedicated transcript microarray to serve as the mRNA identifier by screening
cancer cell lines. NAPPA protein arrays were built to align with the transcript
data with the Chromosome 19 NAPPA chip, dedicated to 90 proteins, as the first
development delivery. We have introduced an IT-infrastructure utilizing a LIMS
system that serves as the key interface for the research teams to share and
explore data generated within the project. The cross-site data repository will
form the basis for sample processing, including biological samples as well as
patient samples from national Biobanks. In an effort to map the human proteome, the Chromosome-centric Human Proteome
Project (C-HPP) was recently initiated. As a member of the international
consortium working on this project, our laboratory developed a gene-centric
proteomic database called GenomewidePDB, which integrates proteomic data for
proteins encoded by chromosomes with transcriptomic data and other information
from public databases. As an example case, we chose chromosome 13, which is the
largest acrocentric human chromosome with the lowest gene density and contains
326 predicted proteins. All proteins stored in GenomewidePDB are linked to other
resources, including neXtProt and Ensembl for protein and gene information,
respectively. The Global Proteome Machine database (GPMdb) and the PeptideAtlas
are also accessed for observed mass spectrometry (MS) information, while Human
Protein Atlas is used for information regarding antibody availability and tissue
expression, respectively. Gene ontology disease information is also included. As
a pilot work, we constructed this GenomewidePDB with the identified 3615
proteins including 53 chromosome 13-origin proteins that are present in normal
human placenta tissue. Thus, developing a comprehensive database containing
actual experimental proteomics data will provide a valuable resource for cross
chromosomal comparison in the C-HPP community. The Chromosome-centric Human Proteome Project (C-HPP) aims to systematically map
the entire human proteome with the intent to enhance our understanding of human
biology at the cellular level. This project attempts simultaneously to establish
a sound basis for the development of diagnostic, prognostic, therapeutic, and
preventive medical applications. In Iran, current efforts focus on mapping the
proteome of the human Y chromosome. The male-specific region of the Y chromosome
(MSY) is unique in many aspects and comprises 95% of the chromosome's length.
The MSY continually retains its haploid state and is full of repeated sequences.
It is responsible for important biological roles such as sex determination and
male fertility. Here, we present the most recent update of MSY protein-encoding
genes and their association with various traits and diseases including sex
determination and reversal, spermatogenesis and male infertility, cancers such
as prostate cancers, sex-specific effects on the brain and behavior, and
graft-versus-host disease. We also present information available from RNA
sequencing, protein-protein interaction, post-translational modification of MSY
protein-coding genes and their implications in biological systems. An overview
of Human Y chromosome Proteome Project is presented and a systematic approach is
suggested to ensure that at least one of each predicted protein-coding gene's
major representative proteins will be characterized in the context of its major
anatomical sites of expression, its abundance, and its functional relevance in a
biological and/or medical context. There are many technical and biological
issues that will need to be overcome in order to accomplish the full scale
mapping. The grand vision of the human proteome project (HPP) is moving closer to reality
with the recent announcement by HUPO of the creation of the HPP consortium in
charge of the development of a two-part HPP, one focused on the description of
proteomes of biological samples or related to diseases (B/D-HPP) and the other
dedicated to a systematic description of proteins as gene products encoded in
the human genome (the C-HPP). This new initiative of HUPO seeks to identify and
characterize at least one representative protein from every gene, create a
protein distribution atlas and a protein pathway or network map. This vision for
proteomics can be the roadmap of biological and clinical research for years to
come if it delivers on its promises. The Industrial Advisory Board (IAB) to HUPO
shares the visions of C-HPP. The IAB will support and critically accompany the
overall project goals and the definitions of the critical milestones. The member
companies are in a unique position to develop hardware and software, reagents
and standards, procedures, and workflows to ensure a reliable source of tools
available to the proteomics community worldwide. In collaboration with academia,
the IAB member companies can and must develop the tools to reach the ambitious
project goals. We offer to partner with and challenge the academic groups
leading the C-HPP to define both ambitious and obtainable goals and milestones
to make the C-HPP a real and trusted resource for future biology. A gene-centric Human Proteome Project has been proposed to characterize the
human protein-coding genes in a chromosome-centered manner to understand human
biology and disease. Here, we report on the protein evidence for all genes
predicted from the genome sequence based on manual annotation from literature
(UniProt), antibody-based profiling in cells, tissues and organs and analysis of
the transcript profiles using next generation sequencing in human cell lines of
different origins. We estimate that there is good evidence for protein existence
for 69% (n = 13985) of the human protein-coding genes, while 23% have only
evidence on the RNA level and 7% still lack experimental evidence. Analysis of
the expression patterns shows few tissue-specific proteins and approximately
half of the genes expressed in all the analyzed cells. The status for each gene
with regards to protein evidence is visualized in a chromosome-centric manner as
part of a new version of the Human Protein Atlas ( www.proteinatlas.org ). |
Where is the protein Pannexin1 located? | The protein Pannexin1 is localized to the plasma membranes. | Our previously reported cDNA array datasets from neonatal wild-type and Cx43-/-
(approved gene symbol Gja1) mouse brains were further analyzed to identify
underlying interlinkages in the brain transcriptome. The analysis revealed that
no gene cohort sharing either primary function or chromosomal location was
significantly altered (up-and down-regulation were roughly balanced) in Cx43-/-
brains, but each cohort exhibited significant perturbation of transcript
abundance proportions and reduced expression variability and coordination. By
comparing pairwise expression correlations of all genes with one another in
wild-type brains, we found genes exhibiting remarkable similarity or opposition
to the coordination profile (set of synergistically, antagonistically, and
independently expressed partners) of Cx43, one of the most similar being
pannexin1, a vertebrate homolog of invertebrate gap junction proteins. This
study indicates striking redundancy of expression controls over functional
pathways and suggests that certain genes may play roles similar to or opposite
that of Cx43 in organizing the brain transcriptome. In the retina, chemical and electrical synapses couple neurons into functional
networks. New candidates encoding for electrical synapse proteins have recently
emerged. In the present study, we determined the localization of the candidate
protein pannexin1 (zfPanx1) in the zebrafish retina and studied the functional
properties of zfPanx1 exogenously expressed in Neuroblastoma 2a (N2a) cells.
zfPanx1 was identified on the surface of horizontal cell dendrites invaginating
deeply into the cone pedicle near the glutamate release sites of the cones,
providing in vivo evidence for hemichannel formation at that location. This
strategic position of zfPanx1 in the photoreceptor synapse could potentially
allow modulation of cone output. Using whole cell voltage clamp and excised
patch recordings of transfected N2a cells, we demonstrated that zfPanx1 forms
voltage-activated hemichannels with a large unitary conductance in vitro. These
channels can open at physiological membrane potentials. Functional channels were
not formed following mutation of a single amino acid within a conserved protein
motif recently shown to be N-glycosylated in rodent Panx1. Together, these
findings indicate that zfPanx1 displays properties similar to its mammalian
homologues and can potentially play an important role in functions of the outer
retina. In mammals, a single pannexin1 gene (Panx1) is widely expressed in the CNS
including the inner and outer retinae, forming large-pore voltage-gated membrane
channels, which are involved in calcium and ATP signaling. Previously, we
discovered that zebrafish lack Panx1 expression in the inner retina, with
drPanx1a exclusively expressed in horizontal cells of the outer retina. Here, we
characterize a second drPanx1 protein, drPanx1b, generated by whole-genome
duplications during teleost evolution. Homology searches strongly support the
presence of pannexin sequences in cartilaginous fish and provide evidence that
pannexins evolved when urochordata and chordata evolution split. Further, we
confirm Panx1 ohnologs being solely present in teleosts. A hallmark of
differential expression of drPanx1a and drPanx1b in various zebrafish brain
areas is the non-overlapping protein localization of drPanx1a in the outer and
drPanx1b in the inner fish retina. A functional comparison of the evolutionary
distant fish and mouse Panx1s revealed both, preserved and unique properties.
Preserved functions are the capability to form channels opening at resting
potential, which are sensitive to known gap junction and hemichannel blockers,
intracellular calcium, extracellular ATP and pH changes. However, drPanx1b is
unique due to its highly complex glycosylation pattern and distinct
electrophysiological gating kinetics. The existence of two Panx1 proteins in
zebrafish displaying distinct tissue distribution, protein modification and
electrophysiological properties, suggests that both proteins fulfill different
functions in vivo. Extracellular ATP is an important signaling molecule throughout the inflammatory
cascade, serving as a danger signal that causes activation of the inflammasome,
enhancement of immune cell infiltration, and fine-tuning of several signaling
cascades including those important for the resolution of inflammation. Recent
studies demonstrated that ATP can be released from cells in a controlled manner
through pannexin (Panx) channels. Panx1-mediated ATP release is involved in
inflammasome activation and neutrophil/macrophage chemotaxis, activation of T
cells, and a role for Panx1 in inducing and propagating inflammation has been
demonstrated in various organs, including lung and the central and peripheral
nervous system. The recognition and clearance of dying cells and debris from
focal points of inflammation is critical in the resolution of inflammation, and
Panx1-mediated ATP release from dying cells has been shown to recruit
phagocytes. Moreover, extracellular ATP can be broken down by ectonucleotidases
into ADP, AMP, and adenosine, which is critical in the resolution of
inflammation. Together, Panx1, ATP, purinergic receptors, and ectonucleotidases
contribute to important feedback loops during the inflammatory response, and
thus represent promising candidates for new therapies. The ATP release channel Pannexin1 (Panx1) is self-regulated, i.e. the permeant
ATP inhibits the channel from the extracellular space. The affinity of the ATP
binding site is lower than that of the purinergic P2X7 receptor allowing a
transient activation of Panx1 by ATP through P2X7R. Here we show that the
inhibition of Panx1 by ATP is abrogated by increased extracellular potassium ion
concentration ([K(+)]o) in a dose-dependent manner. Since increased [K(+)]o is
also a stimulus for Panx1 channels, it can be expected that a combination of ATP
and increased [K(+)]o would be deadly for cells. Indeed, astrocytes did not
survive exposure to these combined stimuli. The death mechanism, although
involving P2X7R, does not appear to strictly follow a pyroptotic pathway.
Instead, caspase-3 was activated, a process inhibited by Panx1 inhibitors. These
data suggest that Panx1 plays an early role in the cell death signaling pathway
involving ATP and K(+) ions. Additionally, Panx1 may play a second role once
cells are committed to apoptosis, since Panx1 is also a substrate of caspase-3. Normal myotubes and adult innervated skeletal myofibers express the glycoprotein
pannexin1 (Panx1). Six of them form a "gap junction hemichannel-like" structure
that connects the cytoplasm with the extracellular space; here they will be
called Panx1 channels. These are poorly selective channels permeable to ions,
small metabolic substrate, and signaling molecules. So far little is known about
the role of Panx1 channels in muscles but skeletal muscles of Panx1(-/-) mice do
not show an evident phenotype. Innervated adult fast and slow skeletal myofibers
show Panx1 reactivity in close proximity to dihydropyridine receptors in the
sarcolemma of T-tubules. These Panx1 channels are activated by electrical
stimulation and extracellular ATP. Panx1 channels play a relevant role in
potentiation of muscle contraction because they allow release of ATP and uptake
of glucose, two molecules required for this response. In support of this notion,
the absence of Panx1 abrogates the potentiation of muscle contraction elicited
by repetitive electrical stimulation, which is reversed by exogenously applied
ATP. Phosphorylation of Panx1 Thr and Ser residues might be involved in Panx1
channel activation since it is enhanced during potentiation of muscle
contraction. Under denervation, Panx1 levels are upregulated and this partially
explains the reduction in electrochemical gradient, however its absence does not
prevent denervation-induced atrophy but prevents the higher oxidative state.
Panx1 also forms functional channels at the cell surface of myotubes and their
functional state has been associated with intracellular Ca(2+) signals and
regulation of myotube plasticity evoked by electrical stimulation. We proposed
that Panx1 channels participate as ATP channels and help to keep a normal
oxidative state in skeletal muscles. Pannexin1 (Panx1) participates in several signaling events that involve
adenosine triphosphate (ATP) release, including the innate immune response,
ciliary beat in airway epithelia, and oxygen supply in the vasculature. The view
that Panx1 forms a large ATP release channel has been challenged by the
association of a low-conductance, small anion-selective channel with the
presence of Panx1. We showed that Panx1 membrane channels can function in two
distinct modes with different conductances and permeabilities when
heterologously expressed in Xenopus oocytes. When stimulated by potassium ions
(K(+)), Panx1 formed a high-conductance channel of ~500 pS that was permeable to
ATP. Various physiological stimuli can induce this ATP-permeable conformation of
the channel in several cell types. In contrast, the channel had a low
conductance (~50 pS) with no detectable ATP permeability when activated by
voltage in the absence of K(+). The two channel states were associated with
different reactivities of the terminal cysteine of Panx1 to thiol reagents,
suggesting different conformations. Single-particle electron microscopic
analysis revealed that K(+) stimulated the formation of channels with a larger
pore diameter than those formed in the absence of K(+). These data suggest that
different stimuli lead to distinct channel structures with distinct biophysical
properties. Pannexin2 (Panx2) is the largest of three members of the pannexin proteins.
Pannexins are topologically related to connexins and innexins, but serve
different functional roles than forming gap junctions. We previously showed that
pannexins form oligomeric channels but unlike connexins and innexins, they form
only single membrane channels. High levels of Panx2 mRNA and protein in the
Central Nervous System (CNS) have been documented. Whereas Pannexin1 (Panx1) is
fairly ubiquitous and Pannexin3 (Panx3) is found in skin and connective tissue,
both are fully glycosylated, traffic to the plasma membrane and have functions
correlated with extracellular ATP release. Here, we describe trafficking and
subcellular localizations of exogenous Panx2 and Panx1 protein expression in
MDCK, HeLa, and HEK 293T cells as well as endogenous Panx1 and Panx2 patterns in
the CNS. Panx2 was found in intracellular localizations, was partially
N-glycosylated, and localizations were non-overlapping with Panx1. Confocal
images of hippocampal sections immunolabeled for the astrocytic protein GFAP,
Panx1 and Panx2 demonstrated that the two isoforms, Panx1 and Panx2, localized
at different subcellular compartments in both astrocytes and neurons. Using
recombit fusions of Panx2 with appended genetic tags developed for correlated
light and electron microscopy and then expressed in different cell lines, we
determined that Panx2 is localized in the membrane of intracellular vesicles and
not in the endoplasmic reticulum as initially indicated by calnexin
colocalization experiments. Dual immunofluorescence imaging with protein markers
for specific vesicle compartments showed that Panx2 vesicles are early endosomal
in origin. In electron tomographic volumes, cross-sections of these vesicles
displayed fine structural details and close proximity to actin filaments. Thus,
pannexins expressed at different subcellular compartments likely exert distinct
functional roles, particularly in the nervous system. The different types of cells in the lung, from the conducting airway epithelium
to the alveolar epithelium and the pulmonary vasculature, are interconnected by
gap junctions. The specific profile of gap junction proteins, the connexins,
expressed in these different cell types forms compartments of intercellular
communication that can be further shaped by the release of extracellular
nucleotides via pannexin1 channels. In this review, we focus on the physiology
of connexins and pannexins and describe how this lung communication network
modulates lung function and host defenses in conductive and respiratory airways. |
Which currently known mitochondrial diseases have been attributed to POLG mutations? | Mutations in the POLG gene have emerged as one of the most common causes of inherited mitochondrial disease in children and adults. They are responsible for a heterogeneous group of at least 6 major phenotypes of neurodegenerative disease that include: 1) childhood Myocerebrohepatopathy Spectrum disorders (MCHS), 2) Alpers syndrome, 3) Ataxia Neuropathy Spectrum (ANS) disorders, 4) Myoclonus Epilepsy Myopathy Sensory Ataxia (MEMSA), 5) autosomal recessive Progressive External Ophthalmoplegia (arPEO), and 6) autosomal dominant Progressive External Ophthalmoplegia (adPEO). | BACKGROUND: Mutations in the gene encoding mitochondrial DNA polymerase gamma
(POLG), the enzyme that synthesises mitochondrial DNA (mtDNA), have been
associated with a mitochondrial disease-autosomal domit or recessive
progressive external ophthalmoplegia-and multiple deletions of mtDNA.
Mitochondrial dysfunction is also suspected to participate in the pathogenesis
of Parkinson's disease. However, no primary gene defects affecting mitochondrial
proteins causing mendelian transmission of parkinsonism have been characterised.
We aimed to analyse the gene sequence of POLG in patients with progressive
external ophthalmoplegia and their healthy relatives.
METHODS: In seven families of various ethnic origins we assessed patients with
progressive external ophthalmoplegia and unaffected individuals by clinical,
biochemical, morphological, and molecular genetic characterisation and positron
emission tomography (PET).
FINDINGS: We recorded mutations in POLG in members of all seven families.
Clinical assessment showed significant cosegregation of parkinsonism with POLG
mutations (p<0.0001), and PET findings were consistent with dopaminergic neuron
loss. Post-mortem examination in two individuals showed loss of pigmented
neurons and pigment phagocytosis in substantia nigra without Lewy bodies.
Furthermore, most women with progressive external ophthalmoplegia had early
menopause-before age 35 years. The POLG gene defect resulted in secondary
accumulation of mtDNA deletions in patients' tissues.
INTERPRETATION: Dysfunction of mitochondrial POLG causes a severe progressive
multisystem disorder including parkinsonism and premature menopause, which are
not typical of mitochondrial disease. Cosegregation of parkinsonism and POLG
mutations in our families suggests that when defective, this gene can underlie
mendelian transmission of parkinsonism.
RELEVANCE TO PRACTICE: Awareness that mitochondrial POLG mutations can underlie
parkinsonism is important for clinicians working in diagnosis of movement
disorders, as well as for studies of the genetics of Parkinson's disease.
Further, progressive external ophthalmoplegia with muscle weakness and
neuropathy can mask symptoms of parkinsonism, and clinicians should pay special
attention to detect and treat parkinsonism in those individuals. Mutations in the POLG gene have emerged as one of the most common causes of
inherited mitochondrial disease in children and adults. They are responsible for
a heterogeneous group of at least 6 major phenotypes of neurodegenerative
disease that include: 1) childhood Myocerebrohepatopathy Spectrum disorders
(MCHS), 2) Alpers syndrome, 3) Ataxia Neuropathy Spectrum (ANS) disorders, 4)
Myoclonus Epilepsy Myopathy Sensory Ataxia (MEMSA), 5) autosomal recessive
Progressive External Ophthalmoplegia (arPEO), and 6) autosomal domit
Progressive External Ophthalmoplegia (adPEO). Due to the clinical heterogeneity,
time-dependent evolution of symptoms, overlapping phenotypes, and
inconsistencies in muscle pathology findings, definitive diagnosis relies on the
molecular finding of deleterious mutations. We sequenced the exons and flanking
intron region from approximately 350 patients displaying a phenotype consistent
with POLG related mitochondrial disease and found informative mutations in 61
(17%). Two mutant alleles were identified in 31 unrelated index patients with
autosomal recessive POLG-related disorders. Among them, 20 (67%) had Alpers
syndrome, 4 (13%) had arPEO, and 3 (10%) had ANS. In addition, 30 patients
carrying one altered POLG allele were found. A total of 25 novel alterations
were identified, including 6 null mutations. We describe the predicted
structural/functional and clinical importance of the previously unreported
missense variants and discuss their likelihood of being pathogenic. In
conclusion, sequence analysis allows the identification of mutations responsible
for POLG-related disorders and, in most of the autosomal recessive cases where
two mutant alleles are found in trans, finding deleterious mutations can provide
an unequivocal diagnosis of the disease. DNA polymerase γ (pol γ), encoded by POLG, is responsible for replicating human
mitochondrial DNA. About 150 mutations in the human POLG have been identified in
patients with mitochondrial diseases such as Alpers syndrome, progressive
external ophthalmoplegia, and ataxia-neuropathy syndromes. Because many of the
mutations are described in single citations with no genotypic family history, it
is important to ascertain which mutations cause or contribute to mitochondrial
disease. The vast majority of data about POLG mutations has been generated from
biochemical characterizations of recombit pol γ. However, recently, the study
of mitochondrial dysfunction in Saccharomyces cerevisiae and mouse models
provides important in vivo evidence for the role of POLG mutations in disease.
Also, the published 3D-structure of the human pol γ assists in explaining some
of the biochemical and genetic properties of the mutants. This review summarizes
the current evidence that identifies and explains disease-causing POLG
mutations. |
What is the effect of ivabradine in heart failure after myocardial infarction? | Ιvabradine decreases heart rate and reduces myocardial oxygen demand, increases diastolic perfusion time and improves energetics in ischemic myocardium. Ivabradine protects the myocardium during ischemia, improves left ventricular function in heart failure and reduces remodeling following myocardial infarction. It improves prognosis in patients with coronary artery disease, left ventricular dysfunction and heart rate ≥70 beats per minute, as well as in patients with heart failure and left ventricular dysfunction. The beneficial effects of ivabradine may be due to the reversal of electrophysiological cardiac remodelling in post-MI rats by reduction of functional overexpression of HCN channels. Furthermore, the improvement of cardiac function is related not only to the HR reduction per se but also to modifications in the extracellular matrix. | BACKGROUND: Heart rate reduction (HRR) improves left ventricular (LV) filling,
increases myocardial O2 supply, and reduces myocardial O2 consumption, which are
all beneficial in congestive heart failure (CHF). However, the long-term effects
of HRR on cardiac function and remodeling are unknown.
METHODS AND RESULTS: We assessed, in rats with CHF, the effects of long-term HRR
induced by the selective I(f) current inhibitor ivabradine (as food admix for 90
days starting 7 days after coronary artery ligation). To assess intrinsic
modifications of LV tissue induced by long-term HRR, all parameters were
reassessed 3 days after interruption of treatment. Ivabradine decreased heart
rate over the 90-day treatment period (-18% versus untreated at 10 mg x kg(-1) x
d(-1)), without modifying blood pressure, LV end-diastolic pressure, or
dP/dt(max/min). Ivabradine significantly reduced LV end-systolic but not
end-diastolic diameter, which resulted in preserved cardiac output due to
increased stroke volume. In the Langendorff preparation, ivabradine shifted LV
systolic but not end-diastolic pressure-volume relations to the left. Ivabradine
decreased LV collagen density and increased LV capillary density without
modifying LV weight. Three days after interruption of treatment, the effects of
ivabradine on LV geometry, shortening, and stroke volume persisted despite
normalization of heart rate.
CONCLUSIONS: In rats with CHF, long-term HRR induced by the selective I(f)
inhibitor ivabradine improves LV function and increases stroke volume,
preserving cardiac output despite the HRR. The improvement of cardiac function
is related not only to the HRR per se but also to modifications in the
extracellular matrix and/or function of myocytes as a consequence of long-term
HRR. AIMS: Effects of the bradycardic agent ivabradine on regional blood flow,
contractile function, and infarct size were studied in a pig model of myocardial
ischaemia/reperfusion. Heart rate reduction by beta-blockade is associated with
negative inotropism and unmasked alpha-adrenergic coronary vasoconstriction.
Ivabradine is the only available bradycardic agent for clinical use.
METHODS AND RESULTS: Anaesthetized pigs were subjected to 90 min controlled left
anterior descending coronary artery hypoperfusion and 120 min reperfusion.
Regional blood flow was measured with microspheres, regional function with
sonomicrometry, and infarct size with triphenyl tetrazolium chloride staining.
Pigs received placebo or ivabradine (0.6 mg/kg i.v.) before or during ischaemia
or before reperfusion, respectively. Pre-treatment with ivabradine reduced
infarct size from 35 +/- 4 (SEM) to 19 +/- 4% of area at risk (AAR). Ivabradine
15-20 min after the onset of ischaemia increased regional myocardial blood flow
from 2.12 +/- 0.31 to 3.55 +/- 0.56 microL/beat/g and systolic wall thickening
from 6.7 +/- 1.0 to 16.3 +/- 3.0%; infarct size was reduced from 12 +/- 4 to 2
+/- 1% of AAR. Ivabradine 5 min before reperfusion still reduced infarct size
from 36 +/- 4 to 21 +/- 5% of AAR. The benefit of ivabradine on flow and
function was eliminated by atrial pacing, but part of the reduction of infarct
size by ivabradine was not.
CONCLUSION: Ivabradine's protection goes beyond heart rate reduction. Collaborators: Grancelli H, Freedman B, Eber B, Vanoverschelde JL, Finkov B,
Yotov Y, Tardif JC, Hu D, Lau C, Hradec J, Hildebrandt P, Eha J, Peuhkurinen K,
Danchin N, Steg PG, Meinertz T, Vardas P, Borbola J, Mulcahy D, Maggioni A,
Erglis A, Jirgensons J, Kalnins U, Laucevicius A, Dickstein K, Ruzyllo W,
Tendera M, Seabra-Gomes R, Capalneanu R, Belenkov Y, Mareev Y, Murin J, Rakovec
P, Macaya C, Dellborg M, Lüscher TU, van Gilst W, Oto A, Ford I, Fox K, Hall A,
Parkhomenko A, Robertson M, Weir C, Aziz J, Kean S, Wilson R, Thygesen K,
Frenneaux M, Jondeau G, Camm AJ, Dargie H, Kjekshus J, Murray G, Ahuad Guerrero
RA, Allall OA, Amuchastegui M, Buscema JJ, Bustos B, Cartasegna LR, Cohen Arazi
H, Ferdez AA, Fuselli JJ, Guzmén LA, Hasbani E, Ibañez JO, Iglesias RM, Lembo
LA, Luciardi HL, Luquez HA, Montaña OR, Nul DR, Orlandini AD, Perna ER, Sanchez
A, Sanjurjo MS, Schygiel PO, Sinisi VA, Sokn FJ, Thierer J, Del Valle Lobo
Marquez LL, Varini S, Vogel D, Alford K, Amerena J, Arnolda L, Atherton J,
Bradley J, Cameron J, Colquhoun D, Counsell J, Fitzpatrick A, Horowitz J,
Ireland M, Karrasch J, Kaye D, Lattimore JD, Marwick T, O'Shea J, Owensby D, de
Pasquale C, Prior D, Rogers J, Sindone A, Singh BB, Stickland J, Szto G, Tofler
G, Vogl E, Waites J, Walsh W, Eber E, Huber K, Lang I, Pichler M, Chenu P,
Dendale PA, François PA, Friart A, Goethals M, Materne P, van Mieghem W,
Missault L, Vachiery JL, Vanderheyden M, Chompalova B, Denchev S, Donova T,
Dzhurzdhev A, Georgiev B, Gotchev D, Goudev A, Grigorov M, Guenova D,
Hergeldjieva V, Kamenova Z, Nachev C, Penkov N, Perchev I, Raev D, Sirakova V,
Taseva T, Torbova S, Tzekova M, Baird M, Bernstein V, Chehayeb R, Constance C,
Coutu B, Desrochers D, Fortin C, Glanz A, Haddad H, Heath J, Hill LL, Klinke WP,
Kouz S, Lalani A, Lauzon C, Lepage S, Lonn E, Ma P, Matangi M, Nawaz S, Pandey
S, Parker JD, Parker JO, Poirier P, Raco D, Rajda M, Rebane T, Rupka D, Savard
D, Syan GS, Talbot P, Tardif JC, To TB, Vakani MT, Vertes GE, Yao L, Dong Y, Gai
L, Ge JB, Hu D, Lv S, Sun Y, Wang W, Wang X, Yan X, Yuan Z, Zhang F, Ballek L,
Drazka J, Fébik L, Florian J, Hradec J, Kaislerová M, Karetová D, Jerábek O,
Kotík L, Krejcova H, Kryza R, Kuchar J, Lavicka V, Maratka T, Marcinek G,
Penicka M, Povolný J, Sochor K, Soucek M, Spacek R, Spinar J, Stípal R, Sulda M,
Vencour D, Vitovec J, Vojacek J, Vojtísek P, Agner E, Asklund M, Brønnum Schou
J, Dahlstrøm CG, Dodt KK, Egstrup K, Gøtzsche L, Gøtzsche O, Haghfelt T,
Hildebrandt P, Jakobsen T, Jensen G, Klarlund K, Køber L, Larsen CT, Larsen J,
Lind Rasmussen S, Lysko Svendsen T, Markenvard J, McNair A, Nielson H, Pedersen
L, Petersen J, Ralfkiaer N, Rickers H, Rokkedal J, Romer F, Roseva Nielsen N,
Scheibel M, Sejersen H, Skagen K, Stentebjerg SE, Torp-Pedersen C, Tuxen C,
Vigholt E, Averina O, Eha J, Kolbassova O, Sildmäe S, Vahula V, Viigimaa M,
Harjola VP, Luoma J, Melin J, Peuhkurinen K, Aliot E, Barthelemy JC, Bauer F,
Beaune J, Belin A, Bodur G, Boudahne A, Bourdon A, Bouvier JM, Carlioz R, Chati
Z, Cherbi C, Chevalier JM, Chevrier J, Claudon O, Colin P, Dambrine P, Danchin
N, Decoulx E, Demarcq JM, Doucet B, Drawin T, Dubois-Rande JL, El Mansour N,
Escande M, Fournier PY, Funck F, Gabrovescu M, Galinier M, Galley D, Gay A,
Genest M, Godenir JP, Guillot JP, Gully C, Habib G, Huyghe de Mahenge A,
Jaboureck O, Kahn JC, Khalife K, Khanoyan P, Koenig A, Leborgne L, Lemoine C,
Magnin D, Mann H, Mansourati J, Martelet M, Matina D, Meurice T, Olive TG, Ovize
M, Perret T, Pierre-Justin E, Riou A, Roudaut R, Roul G, Roynard JL, Sellier P,
Slama M, Soto FX, Thisse JY, Wolf JE, Ammer K, Appel KF, Baar M, Bauknecht C,
Baumann G, Bergmann K, Böhm M, Bosch R, Bott J, Cieslinski G, Deissner M,
Drescher T, Droese K, Figulla HR, Frick HM, Fries P, Gärtner J, Gola G, Gonska
BD, Grooterhorst P, Hasenfuss G, Haverkamp W, Heckel D, Hengstenberg C, Hering
R, Heuer H, Hoppe U, Jahnke N, Jeserich M, Katus H, Kleinertz K, Kombächer HD,
Lange R, Lehmann G, Meinertz T, Müller O, Münzel T, Natour M, Nienaber C, Oeff
M, Pötsch T, Proskynitopoulos N, Rüdell U, Rummel R, Rupprecht HJ, von Schacky
C, Schenkenberger I, Schmidt J, Schreckenberg A, Schuler G, Schultheiss HP,
Seidl K, Spanier C, Spengler U, Steindorf J, Strasser R, Taggeselle J, Tammen A,
Werdan K, Windstetter U, Winkelmann BR, Wolde CH, Zahorsky R, Al-Zoebi A,
Alexopoulos D, Anastasiou-Nana M, Apostolou T, Fotiadis I,
Hatzinikolaou-Kotsakou E, Kallikazaros I, Kapordelis C, Karvounis H, Kolettis T,
Koliopoulos N, Kremastinos D, Kyriakides Z, Manolis A, Papadopoulos C, Pras A,
Pyrgakis VN, Siogas K, Theodorakis G, Tryposkiadis F, Tziakas D, Vardas P, Lee
K, Barsi B, Borbola J, Cziráki A, Dézsi CA, Edes I, Farsang C, Harmati L, Juhász
A, Kovács A, Lakatos F, Lippai J, Lupkovics G, Matoltsy A, Mohácsi A, Mohay A,
Nagy A, Nagy K, Nagy L, Nyárádi A, Pálinkás A, Piros G, Polgár P, Préda I, Regos
L, Rumi G, Sármán P, Sereg M, Sidó Z, Tahy A, Takács J, Tomcsányi J, Tóth K,
Váradi A, Vegh G, Veress G, Zámolyi K, Barton J, Crean P, Daly K, Foley D,
Alberti E, Ambrosio G, Barbuzzi S, Bellone E, Buia E, Capucci A, Carbonieri E,
Cardona N, Della Casa S, Cocchieri M, Colombo A, Cosmi F, De Cristofaro M,
Ferrari R, Fuscaldo G, Gavazzi A, Giannuzzi P, Giustiniani S, Ingrilli F,
Leghissa R, De Luca I, Maresta A, De Matteis C, Minneci C, Mos L, Paparoni S,
Perna B, Pettinati G, Pinelli G, Pizzimenti G, Porcu M, Proietti G, Proto C,
Pulitano G, Reggianini L, Santini M, Uguccioni M, Urbinati S, Zanetta M, Zanini
R, Erglis A, Gailiss E, Gersamija A, Keisa M, Libins A, Ozolina MA, Stoma M,
Volans E, Berukstis E, Grabauskiene V, Kibarskis A, Kirkutis A, Marcinkeviciene
J, Naudziunas A, Petrulioniene Z, Varoneckas G, Zaliunas R, Bartels GL, van Beek
GJ, van den Berg BJ, Bruning TA, Cornel JH, Daniels MC, Dijkgraaf R, Fast J,
Freericks MP, Galema TW, Göbel EJ, Hamer LH, van der Heijden R, Herrman JP,
Hoedemaker G, Holwerda NJ, Hoogslag PA, Jaarsma W, Jap Tjoen San WT, van Kempen
LH, Kirkels JH, Kragten JA, Leenders CM, Linssen GC, Lionarons RJ, Maas AH,
Michels HM, de Milliano PA, Nagelsmit MJ, Nierop PR, Pinto YM, Robles De Medina
R, van Rossum P, van Rugge FP, Somer ST, Swart H, Thijssen H, van der Veen M,
Verheul JA, van Vlies B, Voors AA, Wesdorp JC, van Wijk LM, Willems AR, Winter
JB, Withagen AJ, van der Zwaan C, Zwart PA, Atar D, Dickstein K, Myhre EP,
Achremczyk P, Andrzejak R, Baska J, Bloch C, Dluzniewski M, Drozdowski P, Goch
JH, Janik K, Janion M, Jaworska K, Kalarus Z, Kawecka-Jaszcz K, Kozlowski A,
Krupa E, Krynicki R, Krzciuk M, Krzeminska-Pakula M, Kubica J, Kurowski M,
Kuzniar J, Loboz-Grudzien K, Mazurek W, Miekus P, Musial W, Opolski G, Piepiorka
M, Piotrowski W, Piwowarska W, Pluta W, Ponikowski P, Pulkowski G, Pusz T,
Ruszkowski P, Ruzyllo W, Rynkiewicz A, Sinkiewicz W, Skura M, Slowinski S,
Szolkiewicz M, Szpajer M, Targonski R, Tendera M, Tracz W, Trojnar R,
Trusz-Gluza M, Wodniecki J, Wrabec K, Zadrozna Z, Zinka E, Aguiar J, Carvalho N,
Ferreira Da Silva G, Freitas J, Lousada N, Oliveira Soares A, Paisana Lopes JP,
Providencia LA, Salgado A, Teixeira M, Apetrei E, Arsenescu C, Avram R, Babes K,
Bruckner I, Capalneanu R, Carasca E, Cinteza M, Craiu E, Dan GA, Datcu MD,
Dimulescu DR, Dorobantu M, Dragomor D, Dragulescu IS, Dumitrascu DL, Georgescu
IM, Ionescu DD, Ionascu-Fometescu CR, Kiss L, Macarie C, Manitiu I, Minescu B,
Nanea T, Olariu C, Olinic NC, Opris M, Pop C, Radoi M, Radu I, Sinescu CJ,
Tanaseanu CM, Tase A, Tintoiu I, Tomescu M, Topolnitchi L, Vintila M, Vladoianu
M, Arkhipov MV, Aroutiounov GP, Azarin OG, Barbarash OL, Bart BY, Beloussov YB,
Bychkova L, Chumakova GA, Glezer MG, Golukhova E, Gorbachenkov AA, Gordeev IG,
Ivleva AY, Karpov YA, Karpov YB, Kastanaian AA, Kisliak OA, Kobalava JD,
Konyakhin AY, Khrustalev OA, Kuimov AD, Kukes AG, Lopatin YM, Mareev VY,
Moiseeva OM, Mkrtchyan VR, Nedogoda SV, Orlov VA, Perepech NB, Pimenov LT,
Pozdnyakov YM, Rodoman GV, Rudnev DV, Sayganov SA, Shlyakhto EV, Shostak NA,
Shpektor AV, Sidorenko BA, Sorokin LA, Stryuk RI, Svistov AS, Tankhilevich BM,
Tereschenko SN, Tsyba LP, Vasyuk YA, Vertkine AL, Yakhontova PK, Yakusevich VV,
Yakushin SS, Zadionchenko VS, Zateyshchikov DA, Zhilyaev EV, Bada V, Bugán V,
Gonsorcík J, Kamenský G, Kmec J, Micko K, Murín J, Pella D, Sojka G, Vahala P,
Bombek M, Kanic V, Markez J, Melihen-Bartolic C, Rakove P, Skrabl-Mocnik F,
Slemenik-Pusnik C, Balaguer Recena J, Bertomeu Martinez V, Bruguera Cortada J,
Calvo Gomez C, Calvo Iglesias F, Caparros Valderrama J, Casares Garcia G,
Ferdez Alvarez R, Galve E, Garcia De Burgos F, Grande A, Gusi Tragant G,
Iglesias Alonso LF, Iglesias Cubero G, Illa Gay J, Jimenez Navarro M, López
Bescós L, López García-Aranda V, Macaya De Miguel C, Noriega Peiro F, Paz
Bermejo MA, Perez Villa F, Romero Hinojosa JA, San Román Calvar A, Sevilla Toral
B, Sola Casado R, Bandh A, Blomgren J, Dellborg M, Herlitz J, Ohlin H, Ullman B,
Delabays A, Dubach P, Eeckhout E, Gallino A, Hess O, Moccetti T, Vontobel H,
Acarturk E, Ergene O, Erol K, Kozan O, Mutlu B, Ural D, Yilmaz H, Amosova K,
Barna O, Batushkin V, Bazylevych A, Bereznyakov I, Dyadyk A, Dzyak G, Girina O,
Glushko L, Goloborodko B, Karpenko O, Khomazyuk T, Kolchin Y, Kolomiets S,
Korkushko O, Korzh O, Kovalenko V, Kovalsky I, Krayz I, Kubyshkin V, Lutay M,
Mostovoy Y, Netyazhenko V, Parkhomenko A, Perepelytsya M, Pertseva T, Polyvoda
S, Putintsev V, Rishko LM, Rudyk Y, Sakharchuk I, Semidotska Z, Seredyuk N,
Serkova V, Sharuk O, Slyvka Y, Soldatchenko S, Stadnyuk L, Storozhuk B, Tashchuk
V, Tseluyko V, Vatutin M, Vizir V, Vlasenko M, Voronkov L, Yurlov V, Zharinov O,
Baig MW, Brady A, Brooks N, Brooksby P, Crook JR, Dutka D, Francis CM, Greaves
K, Groves P, Hall A, Kadr H, Lindsay S, Moriarty A, Purvis J, Rozkovec A,
Saltissi S, Stewart M, Timmis A, Williams S. We tested the hypothesis that heart rate (HR) reduction, induced by the
selective hyperpolarization-activated current inhibitor ivabradine (Iva), might
improve left ventricular (LV) function, structure, and electrical remodeling in
severe post-myocardial infarction (MI) chronic heart failure (HF). MI was
produced in adult male Wistar rats. After 2 mo, echocardiography was performed
before the randomization into MI and MI + Iva (10 mg x kg(-1) x day(-1)) groups.
After 3 mo of treatment, echocardiography and 24-h telemetry were recorded.
Cardiac collagen, mRNA, and protein expressions of angiotensin-converting enzyme
(ACE) and ANG II type 1 (AT(1)) receptor were quantified. As a result, at 2 mo
post-MI, all rats displayed severe congestive HF signs (ejection fraction <
30%). At 5 mo post-MI, body and heart weights were similar in the MI and MI +
Iva groups. LV ejection fraction and LV end-diastolic pressure were worsened in
the MI group, whereas both were improved with Iva. Iva reduced HR by 10.4% (P <
0.03 vs. MI) and ventricular premature complexes by 89% (P < 0.03) and improved
HR variability (standard deviation of the RR interval) by 22% (P < 0.05). There
were no effects of Iva on PR, QRS, and QT durations. Interstitial fibrosis in
the MI-remote LV was markedly reduced by Iva (4.0 +/- 0.1 vs. 1.8 +/- 0.1%, P <
0.005). Increases in ventricular gene and protein expressions of ACE and AT(1)
receptor in MI were completely blunted by Iva. In conclusion, these data
indicated that HR reduction by Iva prevents the worsening of LV dysfunction and
remodeling that may be related to a downregulation of cardiac
renin-angiotensin-aldosterone system transcripts. Such beneficial effects of Iva
on cardiac remodeling open new clinical perspectives for the treatment of severe
HF. We compared the effects of heart rate reduction (HRR) by the
hyperpolarization-activated pacemaker current (I(f)) channel inhibitor
ivabradine (MI+Iva) and the beta(1)-blocker atenolol (MI+Aten) on ventricular
remodeling and perfusion after myocardial infarction (MI) in middle-aged (12 mo)
Sprague-Dawley rats. Mean HRR was virtually identical in the two treated groups
(19%). Four weeks after coronary artery ligation, maximal myocardial perfusion
fell in the MI group but was preserved in infarcted rats treated with either Iva
or Aten. However, coronary reserve in the remodeled hearts was preserved only
with Iva, since Aten treatment elevated baseline perfusion in response to a
higher wall stress. The higher maximal perfusion noted in the two treated groups
was not due to arteriogenesis or angiogenesis. Plasma levels of angiotensin
(ANG) II and myocardial ANG type 1 (AT(1)) receptor and transforming growth
factor (TGF)-beta1 were reduced during the first week of treatment by both Iva
and Aten. Moreover, treatment also reduced arteriolar perivascular collagen
density. Despite these similar effects of Iva and Aten on vascularity and ANG
II, Iva, but not Aten, attenuated the decline in ejection fraction and lowered
left ventricular (LV) end-diastolic volume (LVEDV)-to-LV mass ratio, determined
by echocardiography. In conclusion, 1) Iva has advantages over Aten in
postinfarction therapy that are not due to differential effects of the drugs on
heart rate, and 2) age limits growth factor upregulation, angiogenesis, and
arteriogenesis in the postinfarcted heart. Ivabradine is an I(f) current inhibitor, that has documented antianginal
efficacy. The BEAUTIFUL trial tested ivabradine against placebo in a large
population of 10,917 patients in sinus rhythm, with coronary artery disease and
left ventricular dysfunction, defined as left ventricular ejection fraction < or
=35%. Overall, there was no impact of ivabradine on the primary end-point of the
trial (cardiovascular mortality, hospitalisation for myocardial infarction, new
onset or worsening heart failure). In the placebo arm of the trial, baseline
heart rate > or = 70 bpm was associated with an increased risk of cardiovascular
mortality, myocardial infarction, heart failure and coronary revascularisation.
In the subgroup of patients with a baseline heart rate > or =70 bpm, treatment
with ivabradine resulted in a significant, 36% reduction in the risk of
myocardial infarction and a 20% reduction in the need for coronary
revascularisation. Ivabradine was well tolerated, with an increased rate of
treatment discontinuation, mainly due to bradycardia, compared with placebo.
Because of its safety and efficacy to control angina, ivabradine should be
considered first-line antianginal treatment in coronary artery disease patients
with left ventricular dysfunction and increased heart rate, already receiving
beta-blocker therapy or in whom these medications are not tolerated. The BEAUTIFUL (morBidity-mortality EvAlUaTion of the If inhibitor ivabradine in
patients with coronary artery disease and left ventricULar systolic dysfunction)
study assessed the morbidity and mortality benefits of the HR-lowering agent
ivabradine. The placebo arm of the BEAUTIFUL trial was a large cohort of
patients with stable coronary artery disease (CAD) and left ventricular systolic
dysfunction. A subanalysis in the placebo group tested the hypothesis that
elevated resting HR at baseline was a marker for subsequent cardiovascular death
and morbidity. The primary aim of the study was to test whether lowering the HR
with ivabradine reduced cardiovascular death and morbidity in patients with CAD
and left ventricular systolic dysfunction. In the overall analysis, reduction in
HR with ivabradine did not improve cardiac outcomes compared with placebo. The
most important finding of the study was that patients with high baseline HR had
an increase in serious cardiovascular events including death (34%), hospital
admission secondary to congestive heart failure (53%), acute myocardial
infarction (46%), or revascularization procedure (38%). In addition, in the
subset analysis focusing on patients with baseline HR > or =70 bpm and left
ventricular ejection fraction <40% the agent resulted in a 36% decrease in
hospital admissions secondary to fatal and nonfatal myocardial infarction and a
30% decrease in coronary revascularization. The first practical implication from
the study includes that baseline HR should be recorded in addition to other risk
factors such as BP and lipid profile, in the follow-up of patients with CAD.
Attempts should be made to achieve HR <70 bpm by cardiac rehabilitation and
routine use of appropriately dosed beta-blockers. Despite the neutral results
obtained in the BEAUTIFUL study, ivabradine could be administered to the
subgroup of patients in whom HR <70 bpm is not achieved despite proper dosing of
beta-blockers and in those in whom beta-blockers are contraindicated.
Furthermore, in clinical practice, ivabradine may be helpful for patients with
stable CAD who have a high HR while receiving beta-blockers. Future studies are
needed to confirm the hypothesis that single reduction of HR can improve
cardiovascular prognosis. BACKGROUND AND PURPOSE: Recent clinical data suggest beneficial effects of
ivabradine, a specific heart rate (HR)-lowering drug, in heart failure patients.
However, the mechanisms responsible for these effects have not been completely
clarified. Thus, we investigated functional/molecular changes in I(f), the
specific target of ivabradine, in the failing atrial and ventricular myocytes
where this current is up-regulated as a consequence of maladaptive remodelling.
EXPERIMENTAL APPROACH: We investigated the effects of ivabradine (IVA; 10
mg·kg(-1) ·day(-1) for 90 days) on electrophysiological remodelling in left
atrial (LA), left ventricular (LV) and right ventricular (RV) myocytes from
post-mycardial infarcted (MI) rats, with sham-operated (sham or sham + IVA) rats
as controls. I(f) current was measured by patch-clamp;
hyperpolarization-activated cyclic nucleotide-gated (HCN) channel isoforms and
microRNA (miRNA-1 and miR-133) expression were evaluated by reverse
transcription quantitative PCR.
KEY RESULTS: Maximal specific conductance of I(f) was increased in MI, versus
sham, in LV (P < 0.01) and LA myocytes (P < 0.05). Ivabradine reduced HR in both
MI and sham rats (P < 0.05). In MI + IVA, I(f) overexpression was attenuated and
HCN4 transcription reduced by 66% and 54% in LV and RV tissue, respectively,
versus MI rats (all P < 0.05). miR-1 and miR-133, which modulate
post-transcriptional expression of HCN2 and HCN4 genes, were significantly
increased in myocytes from MI + IVA.
CONCLUSION AND IMPLICATION: The beneficial effects of ivabradine may be due to
the reversal of electrophysiological cardiac remodelling in post-MI rats by
reduction of functional overexpression of HCN channels. This is attributable to
transcriptional and post-transcriptional mechanisms. AIM: To study effects of ivabradin on clinicohemodynamic and prognostic
parameters in patients after myocardial infarction (MI) with systolic chronic
cardiac failure (SCCF).
MATERIAL AND METHODS: A population-based randomized prospective trial enrolled
49 patients (40 males--81.6%, mean age 63.1 +/- 8.1 years) with sinus rhythm and
a longer than 3 month history of MI. The patients were randomized into 2 groups:
23 patients of group 1 received standard treatment plus ivabradin, 26 patients
of group 2 received standard treatment alone. Follow-up was 36.1 +/- 6.2 months.
We analysed the trend in heart rate (HR), blood pressure (BP), parameters of
echocardiography, ECG, levels of electrolytes, creatinin in blood plasma,
frequency of hospitalizations, recurrent non-fatal MI and lethality (combined
endpoint).
RESULTS: In the end of the trial ivabradin significantly decreased HR from 71 to
64 b/m. Frequency of combined end point of efficacy was 30.4 and 50% in group 1
and 2, respectively. In group 1 primary end point in high baseline HR occurred
more frequently than in HR < 70 b/m in 6 (50%) and 1 (9.1%) cases, respectively,
but these differences were not significant (p = 0.068). In group 2 the
differences were significant--9 (90%) and 4 (25%) cases, respectively (p =
0.004). By none of the parameters of ECG, plasma electrolytes, creatinine level
significant intergroup differences were found.
CONCLUSION: In the same trend in BP and ECG, group 1 patients showed significant
and more pronounced HR lowering than group 2 patients. Addition of ivabradin to
standard treatment of SCCF after MI promoted less frequency of hospitalizations,
recurrent non-fatal MI, fatal cardiovascular events. This effect was especially
strong in high baseline HR. Major steps have been made in the treatment of ischemic heart disease from the
discovery of nitrates as antianginal medication to the techniques of
percutaneous angioplasty. This incredible therapeutic progress has resulted in a
reduced incidence of ischemic heart disease and related mortality and morbidity.
However, statistical and epidemiological data indicate that in ischemic heart
disease, despite the achievement of great success, there is a necessity for a
further step toward treatment, considering the fact that the characteristics of
this population are changing (increased prevalence of subendocardial infarction
compared with classic transmural infarction, especially in the elderly
population). Furthermore, the need for alternative therapeutic approaches to
traditional ones is recognized. Ranolazine is a selective inhibitor of Na
channels that prevents pathological extension of late Na current developing in
the ischemic myocardial cell. This current is responsible for calcium overload,
with consequent impairment of diastolic relaxation. Ranolazine reduces Na
overload induced by calcium and improves diastolic relaxation and coronary
subendocardial flow, without affecting hemodynamic parameters such as blood
pressure, heart rate, or inotropic state of the heart, avoiding undesirable side
effects. Efficacy of ranolazine has been evaluated in several trials, using
clinical and instrumental endpoints (MARISA and CARISA) or, more recently, using
endpoints such as mortality and reinfarction (ERICA and MERLIN-TIMI 36).
Ivabradine acts through the inhibition of late Na current (also known as If),
which controls the spontaneous diastolic depolarization of sinus node cells. The
partial inhibition of these channels reduces the frequency of sinus node action
potential initiation, resulting in decreased heart rate without effects on
contractility, atrio-ventricular conduction, or repolarization. The BEAUTIFUL
trial has tested whether the effect of ivabradine in lowering heart rate is able
to reduce mortality and cardiovascular morbidity in patients with coronary
artery disease and left ventricular systolic dysfunction. The most significant
results were obtained in the subgroup of patients with life-limiting exertional
angina. In this group, ivabradine significantly reduced the primary endpoint, a
composite of cardiovascular death, hospitalization for fatal and nonfatal acute
myocardial infarction (AMI) or heart failure, by 24%, and hospitalizations for
AMI by 42%. In the subgroup of patients with baseline heart rate >70 bpm,
hospitalizations for AMI and revascularization were reduced by 73% and 59%,
respectively. Chronic stable angina pectoris (CSAP) is the most common manifestation of
coronary artery disease (CAD). Angina pectoris occurs as a result of an
imbalance between myocardial perfusion and the demands of the myocardium.
Elevated heart rate (HR) is an important pathophysiological variable that
increases myocardial oxygen demand, and also limits tissue perfusion by reducing
the duration of diastole during which most myocardial perfusion occurs. Elevated
resting HR represents a significant predictor of all-cause and cardiovascular
mortality in the general population and patients with cardiovascular disease
(CVD) because it assists the progression of CVD through the development of
atherosclerosis, plaque destabilization, and initiation of arrhythmias. Since
β-blockers have been found to reduce HR, therefore, they are currently viewed as
the first line therapy for CSAP and are associated with an improved prognosis
after acute myocardial infarction (AMI) or congestive heart failure (CHF). The
classical treatments for HR reduction have shown negative aspects, such as
β-blockers therapy which exerts negative effects on regional myocardial blood
flow and function when HR reduction is eliminated by atrial pacing. Calcium
channel antagonists functionally antagonize coronary vasoconstriction mediated
through α-adrenoreceptors, and are thus devoid of this undesired effect, but the
compounds are nevertheless negative inotrope. Ivabradine (IVA), a pure HR
lowering drug, reduces the demand of myocardial oxygen during exercise,
contributes to the restoration of oxygen balance and is therefore beneficial in
chronic CVD. No relevant negative effects have been observed on cardiac
conduction, contractility, relaxation, repolarization or blood pressure (BP).
Beneficial effects of IVA have been noticed in CSAP and CHF, with optimal
tolerability profile due to selective interaction with I(f) channel of sino
atrial node cells. More recently, IVA has been highly recommended to be used in
patients with CAD in association with β-blockers. This review highlights the
importance of IVA in the treatment of ischemic heart disease. AIMS: To test the effect of ivabradine on the outcomes in a broad population
with left-ventricular (LV) systolic dysfunction with coronary artery disease
(CAD) and/or heart failure (HF).
METHODS AND RESULTS: Individual trial data from BEAUTIFUL and SHIFT were pooled
to evaluate the effect of ivabradine on the outcomes in patients with LV
dysfunction and heart rate ≥ 70 b.p.m. The pooled population (n = 11 897;
baseline age 62.3 ± 10.4 years, heart rate 79.6 ± 9.2 b.p.m., and LV ejection
fraction 30.3 ± 5.6%) was well treated according to current recommendations (87%
beta-blockers, 90% renin-angiotensin system inhibitors). Median follow-up was 21
months. Treatment with ivabradine was associated with a 13% relative risk
reduction for the composite of cardiovascular mortality or HF hospitalization (P
< 0.001 vs. placebo); this was driven by HF hospitalizations (19%, P < 0.001).
There were also significant relative risk reductions for the composite of
cardiovascular mortality, HF hospitalizations, or myocardial infarction (MI)
hospitalization (15%, P < 0.001); cardiovascular mortality and non-fatal MI
(10%, P = 0.023); and MI hospitalization (23%, P = 0.009). Similar results were
found in patients with differing clinical profiles. Ivabradine was well
tolerated.
CONCLUSION: Ivabradine may be important for the improvement of clinical outcomes
in patients with LV systolic dysfunction and heart rate ≥ 70 b.p.m., whatever
the primary clinical presentation (CAD or HF) or clinical status (NYHA class). |
What is the mode of inheritance of Wilson's disease? | Wilson's disease (WD) is an autosomal recessive disorder. | In a survey in Israel of 50 patients with Wilson's disease, it was found that
this disease occurred in all ethnic groups. In the Arab patients there was a
significantly early age of onset and the disease followed a more severe course
than that in the Jewish patients. The overall sex ratio of patients was nearly
1:1, and genetic analysis of 20 families confirmed an autosomal recessive mode
of inheritance. The very similar age of onset and type of disease within
sibships and the varying ages of onset noted between the Arab and Jewish
patients suggest that the disease is genetically heterogeneous. Dermatoglyphics of 11 patients with Wilson's disease and 16 of their clinically
asymptomatic relatives of first degree were investigated; 11 of the latter ones
were heterozygous in agreement with the turn over rates of Cu-67, 12 under the
assumption of autosomal recessive inheritance. On the finger tips the Mb. Wilson
patients showed 52.7% whorls, their heterozygous relatives about 40%; compared
with our controls (males 33.16%, females 28.82%, Aue-Hauser, 1970) that means a
strong increase of this pattern type. On the palm the high frequency of
hypothenar patterns in homo- and heterozygotes for Wilson's disease and of loops
with accessory triradius in the 4th interdigitum of the patients with Wilson's
disease was striking. Wilson's disease is an inborn error of copper metabolism, characterised by
raised liver-copper concentrations and low serum levels of copper and
caeruloplasmin. The autosomal recessive mode of inheritance strongly suggests
that mutation of a single gene causes the impairment of both caeruloplasmin
synthesis and biliary copper excretion. The normal infant is born with the
biochemical features of Wilson's disease (very high liver-copper levels and low
serum copper and caeruloplasmin). Induction of normal copper metabolism after
birth results in a fall in liver-copper concentrations and rise in serum
caeruloplasmin. The repression of normal copper metabolism in the fetus and its
induction after birth is probably regulated by a controller gene. It is
suggested that mutation of a controller rather than a structural gene underlies
the pathogenesis of Wilson's disease and that the disease results from failure
to switch from the positive copper balance of the fetus to the normal copper
balance of the child. Two problems relating to segregation analysis for Wilson's disease are discussed
and a practical solution is presented. A problem in the ascertainment of
families with Wilson's disease is illustrated by comparing segregation ratios
calculated by the single selection, complete truncate, and multiple incomplete
selection methods. The effect on the segregation ratio of exclusion from the
analysis of those sibs who had died of other diseases at a young age is also
discussed and a method of adjustment of the number of the affected using the
data on age at onset is proposed. The segregation ratio by multiple incomplete
selection (Weinberg proband method) after adjustment for those sibs who had died
of other diseases was 0.243, consistent with the theoretical value for autosomal
recessive inheritance. The segregation ratio calculated by the single selection
method tended to give a lower value, while that calculated by the complete
truncate method was greater than the theoretical value. Recessive inheritance
is, however, supported. The actual effect of exclusion of those sibs who had
died of other diseases on gene frequency estimation is shown to be very small. We report on an otherwise healthy female, mother of two children, with severe
decompensated liver cirrhosis due to an iron overload and Wilson's disease. The
patient was considered heterozygote for hemochromatosis on the basis of the
autosomal recessive inheritance for hemochromatosis, the frequency of the
hemochromatosis gene, and the laboratory parameters defining her iron overload.
The case is interesting because of the coincidence of Wilson's disease and
excessive iron storage. The clinical features of two children of a family with rapidly progressive
extrapyramidal-pyramidal-dementia complex have been described. Inheritance seems
most likely to be autosomal recessive. Magnetic resoce imaging results of
brain were negative. Even so, the authors argued in favor of a diagnosis of
Hallervorden-Spatz disease because the cases fulfilled the clinical criteria for
diagnosis of this disease. Apart from the negative magnetic resoce findings,
the other unusual feature was the early development of levodopa-induced
dyskinesia. Few conditions need to be considered in the differential diagnosis
of a childhood-onset rapidly progressive extrapyramidal syndrome. Such
conditions include Wilson's disease, Hallervorden-Spatz disease (HSD), juvenile
form of Huntington's disease, juvenile neuronal ceroid lipofuscinosis,
early-onset Machado-Joseph disease neuroacanthocytosis, storage disorders, and
variant form of dopa-response dystonias (DRD). Rarer conditions are Leigh's
disease, Lafora body disease, and dentato-rubro-pallido-luysian atrophy. HSD is
a rare disorder characterized by progressive extrapyramidal dysfunction and
dementia. Onset is most commonly in late childhood or early adolescence. The
disease can be familial or sporadic. When familial, it is inherited recessively
and has been linked to chromosome 20. Recently, a mutation in the pantothenate
kinase (PANK2) gene on band 20pl3 has been described in patients with typical
HSD. HSD produces typical magnetic resoce imaging (MRI) changes in brain,
aiding in antemortem diagnosis. The typical finding is of bilaterally
symmetrical hyperintense signal changes in the external segment of globus
pallidus, with surrounding hypointensity on T(2)-weighted image. These imaging
features are fairly diagnostic and have been termed the "eye-of-the tiger sign".
The hyperintensity represents pathologic changes, including gliosis,
demyelination, neuronal loss, and axonal swelling, and the surrounding
hypointensity is caused by loss of signal secondary to iron deposition.
Described herein are the clinical aspects of a family with autosomal recessive
inheritance with rapidly progressive extrapyramidal-pyramidal-dementia complex
but with negative brain MRI results. The diagnosis should be considered a
variant form of HSD. Wilson's disease (WD) is an inborn error of copper metabolism caused by a
mutation to the copper-transporting gene ATP7B. The disease has an autosomal
recessive mode of inheritance, and is characterized by excessive copper
deposition, predomitly in the liver and brain. Diagnosis of the condition
depends primarily on clinical features, biochemical parameters and the presence
of the Kayser-Fleischer ring, and a new diagnostic scoring system has recently
been proposed. Mutations in ATP7B can occur anywhere along the entire 21 exons,
which makes the identification of gene defects particularly challenging.
Identification of carriers and presymptomatic family members of affected
individuals is achieved by polymerase-chain-reaction-based marker analysis. The
traditional treatment for WD is based on copper chelation with agents such as
D-penicillamine, but use of this drug has been questioned because of reported
side effects. The use of agents such as trientine and ammonium
tetrathiomolybdate has been advocated, although results of long-term trials are
awaited. In selected cases, orthotropic hepatic transplantation can reverse the
basic metabolic abnormality in WD and improve both hepatic and neurological
symptoms. Studies of the underlying defects in ATP7B and its suspected modifiers
ATOX1 and COMMD1 are expected to unravel the disease's genotype-phenotype
correlation, and should lead to the design of improved drugs for ameliorating
the suffering of patients. Wilson's disease is an inherited disorder leading to accumulation of copper in
tissues, mainly in the liver and brain. Genetic defect is in the gene coding
ATPase type P (ATP7B). The inheritance is autosomal recessive. Up to now, more
then 500 mutations causing Wilson's disease were described. The most frequent
mutation in Central Europe is mutation H1069Q. The manifestation of Wilson's
disease is usually hepatic or neurologic. Hepatic form is manifested by acute or
chronic hepatitis, steatosis or cirrhosis. Neurologic involvement is manifested
usually after 20 year of age by motor disturbances (tremor, disturbed speech,
problems with writing), which could progress into severe extrapyramidal syndrome
with tremor, rigidity, dysartria, dysfagia and muscle contracture. Diagnosis is
based on clinical and laboratory examinations (neurologic symptoms, liver
disease, low serum ceruloplasmin levels, elevated free copper concentration in
serum, high urine copper excretion, and presence of Kayser-Fleischer rings).
Confirmation of diagnosis is done by hepatic copper concentration in liver
biopsy or by genetic examination. Untreated disease leads to the death of a
patient. Treatment is based on chelating agents decreasing the copper content by
excretion into urine (D-penicillamine, trientine) or on agents preventing
absorption of copper from food (zinc, ammonium-tetrahiomolybdene). Patients with
asymptomatic Wilson's disease have to be treated as well. In Czech Republic
either penicillamine or zinc are used. Liver transplantation is indicated in
patients with fulmit liver failure or decompensated cirrhosis. Screening in
families of affected patients (all siblings) is obvious. Wilson's disease (WD), or hepatolenticular degeneration, is an autosomal
recessive inheritance disorder of copper metabolism caused by ATP7B gene
mutation. As WD is an inherited disease of the nervous system that is not
curable; early diagnosis with early and life-long treatment leads to better
prognoses. Currently, the recommended treatment for WD is integrated Chinese and
Western medicine. A number of studies indicate that treatment of integrative
medicine can not only enforce the de-copper effect but also improve liver
function, intelligence, and other factors. This article reviewed in detail the
advantages of WD treated with Chinese and Western medicine together. |
Are transcription and splicing connected? | Yes. There is strong evidence that splicing and transcription are intimately coupled in metazoans, with genome wide surveys show that most splicing occurs during transcription. Chromatin structure, RNA polymerase dynamics, and recruitment of splicing factors through the transcriptional machinery are factors that explain a role for transcription in the regulation of splicing. | Transcription and pre-mRNA splicing are extremely complex multimolecular
processes that involve protein-DNA, protein-RNA, and protein-protein
interactions. Splicing occurs in the close vicinity of genes and is frequently
cotranscriptional. This is consistent with evidence that both processes are
coordinated and, in some cases, functionally coupled. This review focuses on the
roles of cis- and trans-acting factors that regulate transcription, on
constitutive and alternative splicing. We also discuss possible functions in
splicing of the C-terminal domain (CTD) of the RNA polymerase II (pol II)
largest subunit, whose participation in other key pre-mRNA processing reactions
(capping and cleavage/polyadenylation) is well documented. Recent evidence
indicates that transcriptional elongation and splicing can be influenced
reciprocally: Elongation rates control alternative splicing and splicing factors
can, in turn, modulate pol II elongation. The presence of transcription factors
in the spliceosome and the existence of proteins, such as the coactivator PGC-1,
with dual activities in splicing and transcription can explain the links between
both processes and add a new level of complexity to the regulation of gene
expression in eukaryotes. Cotranscriptional loading of RNA processing factors onto nascent RNA facilitates
efficient gene expression. Mechanisms responsible for coupling transcription and
RNA processing are not well defined, but the Saccharomyces cerevisiae TREX
complex provides an example. TREX is composed of the subcomplex THO that
associates with RNA polymerase II and is required for normal transcriptional
elongation. THO associates with proteins involved in RNA splicing and export to
form the larger TREX complex. Hence, assembly of TREX physically couples
transcriptional elongation with RNA processing factors. Whether metazoan species
with long, intron-containing genes utilize a similar mechanism has not been
established. Here we show that human hHpr1/p84/Thoc1 associates with elongating
RNA polymerase II and the RNA splicing and export factor UAP56 in intact cells.
Depletion of hHpr1/p84/Thoc1 causes transcriptional elongation defects and
associated cellular phenotypes similar to those observed in THO-deficient yeast.
We conclude that hHpr1/p84/Thoc1 regulates transcriptional elongation and may
participate in a protein complex functionally analogous to yeast TREX,
physically linking elongating RNA polymerase II with RNA processing factors. HIV-1 Tat binds human CyclinT1 and recruits the CDK9/P-TEFb complex to the viral
TAR RNA in a step that links RNA polymerase II (RNAPII) C-terminal domain (CTD)
Ser 2 phosphorylation with transcription elongation. Previous studies have
suggested a connection between Tat and pre-mRNA splicing factors. Here we show
that the splicing-associated c-Ski-interacting protein, SKIP, is required for
Tat transactivation in vivo and stimulates HIV-1 transcription elongation, but
not initiation, in vitro. SKIP associates with CycT1:CDK9/P-TEFb and Tat:P-TEFb
complexes in nuclear extracts and interacts with recombit Tat:P-TEFb:TAR RNA
complexes in vitro, indicating that it may act through nascent RNA to overcome
pausing by RNAPII. SKIP also associates with U5snRNP proteins and tri-snRNP110K
in nuclear extracts, and facilitates recognition of an alternative Tat-specific
splice site in vivo. The effects of SKIP on transcription elongation, binding to
P-TEFb, and splicing are mediated through the SNW domain. HIV-1 Tat
transactivation is accompanied by the recruitment of P-TEFb, SKIP, and
tri-snRNP110K to the integrated HIV-1 promoter in vivo, whereas the U5snRNPs
associate only with the transcribed coding region. These findings suggest that
SKIP plays independent roles in transcription elongation and pre-mRNA splicing. Splicing is an important process for regulation of gene expression in
eukaryotes, and it has important functional links to other steps of gene
expression. Two examples of these linkages include Ceg1, a component of the mRNA
capping enzyme, and the chromatin elongation factors Spt4-5, both of which have
recently been shown to play a role in the normal splicing of several genes in
the yeast Saccharomyces cerevisiae. Using a genomic approach to characterize the
roles of Spt4-5 in splicing, we used splicing-sensitive DNA microarrays to
identify specific sets of genes that are mis-spliced in ceg1, spt4, and spt5
mutants. In the context of a complex, nested, experimental design featuring 22
dye-swap array hybridizations, comprising both biological and technical
replicates, we applied five appropriate statistical models for assessing
differential expression between wild-type and the mutants. To refine selection
of differential expression genes, we then used a robust model-synthesizing
approach, Differential Expression via Distance Synthesis, to integrate all five
models. The resultant list of differentially expressed genes was then further
analyzed with regard to select attributes: we found that highly transcribed
genes with long introns were most sensitive to spt mutations. QPCR confirmation
of differential expression was established for the limited number of genes
evaluated. In this paper, we showcase splicing array technology, as well as
powerful, yet general, statistical methodology for assessing differential
expression, in the context of a real, complex experimental design. Our results
suggest that the Spt4-Spt5 complex may help coordinate splicing with
transcription under conditions that present kinetic challenges to spliceosome
assembly or function. Coupling between transcription and RNA processing is a key gene regulatory
mechanism. Here we use chromatin immunoprecipitation to detect
transcription-dependent accumulation of the precursor mRNA (pre-mRNA) splicing
factors hnRNP A1, U2AF65 and U1 and U5 snRNPs on the intron-containing human FOS
gene. These factors were poorly detected on intronless heat-shock and histone
genes, a result that opposes direct recruitment by RNA polymerase II (Pol II) or
the cap-binding complex in vivo. However, an observed RNA-dependent interaction
between U2AF65 and active forms of Pol II may stabilize U2AF65 binding to
intron-containing nascent RNA. We establish chromatin-RNA immunoprecipitation
and show that FOS pre-mRNA is cotranscriptionally spliced. Notably, the
topoisomerase I inhibitor camptothecin, which stalls elongating Pol II,
increased cotranscriptional splicing factor accumulation and splicing in
parallel. This provides direct evidence for a kinetic link between
transcription, splicing factor recruitment and splicing catalysis. Recent ChIP experiments indicate that spliceosome assembly and splicing can
occur cotranscriptionally in S. cerevisiae. However, only a few genes have been
examined, and all have long second exons. To extend these studies, we analyzed
intron-containing genes with different second exon lengths by using ChIP as well
as whole-genome tiling arrays (ChIP-CHIP). The data indicate that U1 snRNP
recruitment is independent of exon length. Recursive splicing constructs, which
uncouple U1 recruitment from transcription, suggest that cotranscriptional U1
recruitment contributes to optimal splicing efficiency. In contrast, U2 snRNP
recruitment, as well as cotranscriptional splicing, is deficient on short second
exon genes. We estimate that > or =90% of endogenous yeast splicing is
posttranscriptional, consistent with an analysis of posttranscriptional
snRNP-associated pre-mRNA. Alternative splicing of pre-messenger RNA is a key feature of transcriptome
expansion in eukaryotic cells, yet its regulation is poorly understood.
Spliceosome assembly occurs co-transcriptionally, raising the possibility that
DNA structure may directly influence alternative splicing. Supporting such an
association, recent reports have identified distinct histone methylation
patterns, elevated nucleosome occupancy and enriched DNA methylation at exons
relative to introns. Moreover, the rate of transcription elongation has been
linked to alternative splicing. Here we provide the first evidence that a
DNA-binding protein, CCCTC-binding factor (CTCF), can promote inclusion of weak
upstream exons by mediating local RNA polymerase II pausing both in a mammalian
model system for alternative splicing, CD45, and genome-wide. We further show
that CTCF binding to CD45 exon 5 is inhibited by DNA methylation, leading to
reciprocal effects on exon 5 inclusion. These findings provide a mechanistic
basis for developmental regulation of splicing outcome through heritable
epigenetic marks. To determine the prevalence of cotranscriptional splicing in Drosophila, we
sequenced nascent RNA transcripts from Drosophila S2 cells as well as from
Drosophila heads. Eighty-seven percent of the introns assayed manifest >50%
cotranscriptional splicing. The remaining 13% are cotranscriptionally spliced
poorly or slowly, with ∼3% being almost completely retained in nascent pre-mRNA.
Although individual introns showed slight but statistically significant
differences in splicing efficiency, similar global levels of splicing were seen
from both sources. Importantly, introns with low cotranscriptional splicing
efficiencies are present in the same primary transcript with efficiently spliced
introns, indicating that splicing is intron-specific. The analysis also
indicates that cotranscriptional splicing is less efficient for first introns,
longer introns, and introns annotated as alternative. Finally, S2 cells
expressing the slow RpII215(C4) mutant show substantially less intron retention
than wild-type S2 cells. Here we present the development and implementation of a genome-wide reverse
genetic screen in the budding yeast, Saccharomyces cerevisiae, that couples
high-throughput strain growth, robotic RNA isolation and cDNA synthesis, and
quantitative PCR to allow for a robust determination of the level of nearly any
cellular RNA in the background of ~5,500 different mutants. As an initial test
of this approach, we sought to identify the full complement of factors that
impact pre-mRNA splicing. Increasing lines of evidence suggest a relationship
between pre-mRNA splicing and other cellular pathways including chromatin
remodeling, transcription, and 3' end processing, yet in many cases the specific
proteins responsible for functionally connecting these pathways remain unclear.
Moreover, it is unclear whether all pathways that are coupled to splicing have
been identified. As expected, our approach sensitively detects pre-mRNA
accumulation in the vast majority of strains containing mutations in known
splicing factors. Remarkably, however, several additional candidates were found
to cause increases in pre-mRNA levels similar to that seen for canonical
splicing mutants, none of which had previously been implicated in the splicing
pathway. Instead, several of these factors have been previously implicated to
play roles in chromatin remodeling, 3' end processing, and other novel
categories. Further analysis of these factors using splicing-sensitive
microarrays confirms that deletion of Bdf1, a factor that links transcription
initiation and chromatin remodeling, leads to a global splicing defect,
providing evidence for a novel connection between pre-mRNA splicing and this
component of the SWR1 complex. By contrast, mutations in 3' end processing
factors such as Cft2 and Yth1 also result in pre-mRNA splicing defects, although
only for a subset of transcripts, suggesting that spliceosome assembly in S.
cerevisiae may more closely resemble mammalian models of exon-definition. More
broadly, our work demonstrates the capacity of this approach to identify novel
regulators of various cellular RNAs. Alternative splicing has emerged as a key contributor to proteome diversity,
highlighting the importance of understanding its regulation. In recent years it
became apparent that splicing is predomitly cotranscriptional, allowing for
crosstalk between these two nuclear processes. We discuss some of the links
between transcription and splicing, with special emphasis on the role played by
transcription elongation in the regulation of alternative splicing events and in
particular the kinetic model of alternative splicing regulation. This article is
part of a Special Issue entitled: RNA polymerase II Transcript Elongation. Splicing and alternative splicing are involved in the expression of most human
genes, playing key roles in differentiation, cell cycle progression, and
development. Misregulation of splicing is frequently associated to disease,
which imposes a better understanding of the mechanisms underlying splicing
regulation. Accumulated evidence suggests that multiple trans-acting factors and
cis-regulatory elements act together to determine tissue-specific splicing
patterns. Besides, as splicing is often cotranscriptional, a complex picture
emerges in which splicing regulation not only depends on the balance of splicing
factor binding to their pre-mRNA target sites but also on
transcription-associated features such as protein recruitment to the
transcribing machinery and elongation kinetics. Adding more complexity to the
splicing regulation network, recent evidence shows that chromatin structure is
another layer of regulation that may act through various mechanisms. These span
from regulation of RNA polymerase II elongation, which ultimately determines
splicing decisions, to splicing factor recruitment by specific histone marks.
Chromatin may not only be involved in alternative splicing regulation but in
constitutive exon recognition as well. Moreover, splicing was found to be
necessary for the proper 'writing' of particular chromatin signatures, giving
further mechanistic support to functional interconnections between splicing,
transcription and chromatin structure. These links between chromatin
configuration and splicing raise the intriguing possibility of the existence of
a memory for splicing patterns to be inherited through epigenetic modifications. Spliceosome assembly and/or splicing of a nascent transcript may be crucial for
proper isoform expression and gene regulation in higher eukaryotes. We recently
showed that cotranscriptional splicing occurs efficiently in Drosophila, but
there are not comparable genome-wide nascent splicing data from mammals. To
provide this comparison, we analyze a recently generated, high-throughput
sequencing data set of mouse liver nascent RNA, originally studied for circadian
transcriptional regulation. Cotranscriptional splicing is approximately twofold
less efficient in mouse liver than in Drosophila, i.e., nascent intron levels
relative to exon levels are ∼0.55 in mouse versus 0.25 in the fly. An additional
difference between species is that only mouse cotranscriptional splicing is
optimal when 5'-exon length is between 50 and 500 bp, and intron length does not
correlate with splicing efficiency, consistent with exon definition. A similar
analysis of intron and exon length dependence in the fly is more consistent with
intron definition. Contrasted with these differences are many similarities
between the two systems: Alternatively annotated introns are less efficiently
spliced cotranscriptionally than constitutive introns, and introns of
single-intron genes are less efficiently spliced than introns from multi-intron
genes. The most striking common feature is intron position: Cotranscriptional
splicing is much more efficient when introns are far from the 3' ends of their
genes. Additionally, absolute gene length correlates positively with
cotranscriptional splicing efficiency independently of intron location and
position, in flies as well as in mice. The gene length and distance effects
indicate that more "nascent time" gives rise to greater cotranscriptional
splicing efficiency in both systems. Eukaryotic gene expression involves tight coordination between transcription and
pre-mRNA splicing; however, factors responsible for this coordination remain
incompletely defined. Here, we explored the genetic, functional, and biochemical
interactions of a likely coordinator, Npl3, an SR-like protein in Saccharomyces
cerevisiae that we recently showed is required for efficient co-transcriptional
recruitment of the splicing machinery. We surveyed the NPL3 genetic interaction
space and observed a significant enrichment for genes involved in histone
modification and chromatin remodeling. Specifically, we found that Npl3
genetically interacts with both Bre1, which mono-ubiquitinates histone H2B as
part of the RAD6 Complex, and Ubp8, the de-ubiquitinase of the SAGA Complex. In
support of these genetic data, we show that Bre1 physically interacts with Npl3
in an RNA-independent manner. Furthermore, using a genome-wide splicing
microarray, we found that the known splicing defect of a strain lacking Npl3 is
exacerbated by deletion of BRE1 or UBP8, a phenomenon phenocopied by a point
mutation in H2B that abrogates ubiquitination. Intriguingly, even in the
presence of wild-type NPL3, deletion of BRE1 exhibits a mild splicing defect and
elicits a growth defect in combination with deletions of early and late splicing
factors. Taken together, our data reveal a connection between Npl3 and an
extensive array of chromatin factors and describe an uticipated functional
link between histone H2B ubiquitination and pre-mRNA splicing. |
What is the mode of inheritance of Facioscapulohumeral muscular dystrophy (FSHD)? | Facioscapulohumeral muscular dystrophy has an autosomal dominant inheritance pattern. | Extrapolating the figures from a previous study on FSHD in a province of The
Netherlands to the entire Dutch population suggests that at present a nearly
complete overview is obtained of all symptomatic kindred. In 139 families,
domit inheritance was observed in 97, a pattern compatible with germline
mosaicism in 6, while sporadic cases were found in 36 families. A mutation
frequency of 9.6% was calculated. Mental retardation and severe retinal
vasculopathy were reported in low frequencies (1%). Early onset was seen more
frequently in sporadic cases. Chromosome 4 linkage appeared excluded in 3 of 22
autosomal-domit families. The clinical pictures in the linked and nonlinked
families were identical. Facioscapulohumeral dystrophy (FSHD) is an autosomal-domit muscular disorder
associated with a short (<35 kb) EcoRI/BlnI fragment resulting from deletion of
an integral number of units of a 3.3-kb repeat located at 4q35. In this study,
we determined fragment sizes separated by pulsed-field gel electrophoresis in a
patient with an apparently sporadic case of FSHD and in his healthy family
members. A 38-kb fragment was detected in the proband, in his older brother, and
in their father. This finding prompted a clinical reevaluation of the father and
brother. A subclinical phenotype restricted to abdominal muscle weakness was
detected, and serum creatine kinase values were found to be elevated in both.
The proband's brother also showed evidence of an independently occurring
subtelomeric rearrangement of 4q35, which normally occurs in about 20% of the
population. The identification of a "borderline" 38-kb EcoRI/BlnI fragment in an
affected subject and his very mildly affected relatives extends the size range
of disease alleles and expands existing data on the variable intrafamilial
expressivity of FSHD. This study highlights the importance of a careful
molecular and clinical analysis extended to family members of apparently
sporadic cases with larger EcoRI/BlnI fragments for accurate diagnosis and
appropriate genetic counseling in FSHD. Facioscapulohumeral muscular dystrophy (FSHD) is a slowly progressive myopathy
with autosomal domit inheritance remarkable for its early involvement of
facial musculature. The purpose of our study was to assess the rate of strength
deterioration, functional condition and performance of activity of daily living
of patients with FSHD in Taiwan. Twenty patients diagnosed with FSHD were
included in this study. Manual muscle testing (MMT) was used to evaluate muscle
strength. The Brooke and Vignos scales were used to assess upper and lower
extremity function respectively, and the capability of the activity of daily
living was measured by Barthel index. The result of the strength testing was
characterized by the presence of a progressive asymmetrical muscular weakness in
patients with FSHD. The mean muscular strength of the right extremity was weaker
than its left counterparts (p < 0.05) and the shoulder muscle group was the
weakest. According to the Brooke functional scale, 20% of our patients were
graded as 1, 30% as grade 2, and 50% as grade 3. On the Vignos functional scale,
50% of patients fell into grade 1, 10% in grade 2, and 40% in grades 3-5. Vignos
scale was significantly correlated with mean muscle strength (p < 0.05). The
average value of Barthel index was 97.8 +/- 4.7. The muscle strength decline in
this Taiwanese of FSHD population was more severe in shoulder girdle area. The
mean muscle strength of the right extremity was weaker than the left. Most of
our patients suffered from mild or moderate physical disability. Finding of
these Taiwanese FSHD population is similar to those reported elsewhere in the
world. A 60-year-old man diagnosed clinically with Becker's muscular dystrophy 20 years
ago by another physician presented with gradually progressive proximal muscle
weakness since teenage years. Family history revealed a strong paternal familial
inheritance pattern of similar distribution of weakness-face, forearm flexion,
knee extension and foot dorsiflexion. Work-ups revealed B12 deficiency and
allele 1 deletion in fascioscapulohumeral muscular dystrophy (FSHD) DNA testing.
FSHD is the third most common muscular dystrophy. Clinical diagnosis is made
from the distinctive pattern of weakness, autosomal-domit inheritance, and
confirmed by genetic testing. This case strongly demonstrates the importance of
a thorough and careful clinical evaluation even in a case with a long standing
diagnosis. Facioscapulohumeral muscular dystrophy (FSHD) is a neuromuscular disease,
characterized by an autosomal domit mode of inheritance, facial involvement,
and selectivity and asymmetry of muscle involvement. In general, FSHD typically
presents before age 20 years. Usually, FSHD muscle involvement starts in the
face and then progresses to the shoulder girdle, the humeral muscles and the
abdominal muscles, and then the anterolateral compartment of the leg. Disease
severity is highly variable and progression is very slow. About 20% of FSHD
patients become wheelchair-bound. Lifespan is not shortened. The diagnosis of
FSHD is based on a genetic test by which a deletion of 3.3kb DNA repeats (named
D4Z4 and mapping to the subtelomeric region of chromosome 4q35) is identified.
The progressive pattern of FSHD requires that the severity of symptoms as well
as their physical, social and psychological impact be evaluated on a regular
basis. A yearly assessment is recommended. Multidisciplinary management of
FSHD--consisting of a combination of genetic counselling, functional assessment,
an assessment by a physical therapist, prescription of symptomatic therapies and
prevention of known complications of this disease--is required. Prescription of
physical therapy sessions and orthopedic appliances are to be adapted to the
patient's deficiencies and contractures. Facioscapulohumeral dystrophy (FSHD) is characterized by chromatin relaxation of
the D4Z4 macrosatellite array on chromosome 4 and expression of the D4Z4-encoded
DUX4 gene in skeletal muscle. The more common form, autosomal domit FSHD1, is
caused by contraction of the D4Z4 array, whereas the genetic determits and
inheritance of D4Z4 array contraction-independent FSHD2 are unclear. Here, we
show that mutations in SMCHD1 (encoding structural maintece of chromosomes
flexible hinge domain containing 1) on chromosome 18 reduce SMCHD1 protein
levels and segregate with genome-wide D4Z4 CpG hypomethylation in human
kindreds. FSHD2 occurs in individuals who inherited both the SMCHD1 mutation and
a normal-sized D4Z4 array on a chromosome 4 haplotype permissive for DUX4
expression. Reducing SMCHD1 levels in skeletal muscle results in D4Z4
contraction-independent DUX4 expression. Our study identifies SMCHD1 as an
epigenetic modifier of the D4Z4 metastable epiallele and as a causal genetic
determit of FSHD2 and possibly other human diseases subject to epigenetic
regulation. |
Is Alu hypomethylation associated with breast cancer? | Yes, Alu elements were found to be hypomethylated in breast cancer, especially in the HER2-enriched subtype. Furthermore, Alu hypomethylation was identified as a late event during breast cancer progression, and in invasive breast cancer, tended to be associated with negative estrogen receptor status and poor disease-free survival of the patients. | The changes in DNA methylation status in cancer cells are characterized by
hypermethylation of promoter CpG islands and diffuse genomic hypomethylation.
Alu and long interspersed nucleotide element-1 (LINE-1) are non-coding genomic
repetitive sequences and methylation of these elements can be used as a
surrogate marker for genome-wide methylation status. This study was designed to
evaluate the changes of Alu and LINE-1 hypomethylation during breast cancer
progression from normal to pre-invasive lesions and invasive breast cancer
(IBC), and their relationship with characteristics of IBC. We analyzed the
methylation status of Alu and LINE-1 in 145 cases of breast samples including
normal breast tissue, atypical ductal hyperplasia/flat epithelial atypia
(ADH/FEA), ductal carcinoma in situ (DCIS) and IBC, and another set of 129 cases
of IBC by pyrosequencing. Alu methylation showed no significant changes during
multistep progression of breast cancer, although it tended to decrease during
the transition from DCIS to IBC. In contrast, LINE-1 methylation significantly
decreased from normal to ADH/FEA, while it was similar in ADH/FEA, DCIS and IBC.
In IBC, Alu hypomethylation correlated with negative estrogen receptor (ER)
status, and LINE-1 hypomethylation was associated with negative ER status, ERBB2
(HER2) amplification and p53 overexpression. Alu and LINE-1 methylation status
was significantly different between breast cancer subtypes, and the HER2
enriched subtype had lowest methylation levels. In survival analyses, low Alu
methylation status tended to be associated with poor disease-free survival of
the patients. Our findings suggest that LINE-1 hypomethylation is an early event
and Alu hypomethylation is probably a late event during breast cancer
progression, and prominent hypomethylation of Alu and LINE-1 in HER2 enriched
subtype may be related to chromosomal instability of this specific subtype. |
Which proteins participate in the formation of the ryanodine receptor quaternary macromolecular complex? | Junctin is a major transmembrane protein in cardiac junctional sarcoplasmic reticulum, which forms a quaternary complex with the ryanodine receptor (Ca(2+) release channel), triadin, and calsequestrin. | Triadin 1 is a major transmembrane protein in cardiac junctional sarcoplasmic
reticulum (SR), which forms a quaternary complex with the ryanodine receptor
(Ca(2+) release channel), junctin, and calsequestrin. To better understand the
role of triadin 1 in excitation-contraction coupling in the heart, we generated
transgenic mice with targeted overexpression of triadin 1 to mouse atrium and
ventricle, employing the alpha-myosin heavy chain promoter to drive protein
expression. The protein was overexpressed 5-fold in mouse ventricles, and
overexpression was accompanied by cardiac hypertrophy. The levels of two other
junctional SR proteins, the ryanodine receptor and junctin, were reduced by 55%
and 73%, respectively, in association with triadin 1 overexpression, whereas the
levels of calsequestrin, the Ca(2+)-binding protein of junctional SR, and of
phospholamban and SERCA2a, Ca(2+)-handling proteins of the free SR, were
unchanged. Cardiac myocytes from triadin 1-overexpressing mice exhibited
depressed contractility; Ca(2+) transients decayed at a slower rate, and cell
shortening and relengthening were diminished. The extent of depression of cell
shortening of triadin 1-overexpressing cardiomyocytes was rate-dependent, being
more depressed under low stimulation frequencies (0.5 Hz), but reaching
comparable levels at higher frequencies of stimulation (5 Hz). Spontaneously
beating, isolated work-performing heart preparations overexpressing triadin 1
also relaxed at a slower rate than control hearts, and failed to adapt to
increased afterload appropriately. The fast time inactivation constant, tau(1),
of the l-type Ca(2+) channel was prolonged in transgenic cardiomyocytes. Our
results provide evidence for the coordinated regulation of junctional SR protein
expression in heart independent of free SR protein expression, and furthermore
suggest an important role for triadin 1 in regulating the contractile properties
of the heart during excitation-contraction coupling. OBJECTIVE: Junctin is a major transmembrane protein in cardiac junctional
sarcoplasmic reticulum, which forms a quaternary complex with the ryanodine
receptor (Ca(2+) release channel), triadin, and calsequestrin.
METHODS: To better understand the role of junctin in excitation-contraction
coupling in the heart, we generated transgenic mice with targeted overexpression
of junctin to mouse heart, using the alpha-MHC promoter to drive protein
expression.
RESULTS: The protein was overexpressed 10-fold in mouse ventricles and
overexpression was accompanied by cardiac hypertrophy (19%). The levels of two
other junctional SR-proteins, the ryanodine receptor and triadin, were reduced
by 32% and 23%, respectively. However, [3H]ryanodine binding and the expression
levels of calsequestrin, phospholamban and SERCA2a remained unchanged.
Cardiomyocytes from junctin-overexpressing mice exhibited impaired relaxation:
Ca(2+) transients decayed at a slower rate and cell relengthening was prolonged.
Isolated electrically stimulated papillary muscles from junctin-overexpressing
hearts exhibited prolonged mechanical relaxation, and echocardiographic
parameters of relaxation were prolonged in the living transgenic mice. The
amplitude of caffeine-induced Ca(2+) transients was lower in cardiomyocytes from
junctin-overexpressing mice. The inactivation kinetics of L-type Ca(2+) channel
were prolonged in junctin-overexpressing cardiomyocytes using Ca(2+) or Ba(2+)
as charge carriers.
CONCLUSION: Our data provide evidence that cardiac-specific overexpression of
junctin is accompanied by impaired myocardial relaxation with prolonged Ca(2+)
transient kinetics on the cardiomyocyte level. In mammalian striated muscles, ryanodine receptor (RyR), triadin, junctin, and
calsequestrin form a quaternary complex in the lumen of sarcoplasmic reticulum.
Such intermolecular interactions contribute not only to the passive buffering of
sarcoplasmic reticulum luminal Ca2+, but also to the active Ca2+ release process
during excitation-contraction coupling. Here we tested the hypothesis that
specific charged amino acids within the luminal portion of RyR mediate its
direct interaction with triadin. Using in vitro binding assay and site-directed
mutagenesis, we found that the second intraluminal loop of the skeletal muscle
RyR1 (amino acids 4860-4917), but not the first intraluminal loop of RyR1 (amino
acids 4581-4640) could bind triadin. Specifically, three negatively charged
residues Asp4878, Asp4907, and Glu4908 appear to be critical for the association
with triadin. Using deletional approaches, we showed that a KEKE motif of
triadin (amino acids 200-232) is essential for the binding to RyR1. Because the
second intraluminal loop of RyR has been previously shown to contain the
ion-conducting pore as well as the selectivity filter of the Ca2+ release
channel, and Asp4878, Asp4907, and Glu4908 residues are predicted to locate at
the periphery of the pore assembly of the channel, our data suggest that a
physical interaction between RyR1 and triadin could play an active role in the
overall Ca2+ release process of excitation-contraction coupling in muscle cells. Junctin is a transmembrane protein of the cardiac junctional sarcoplasmic
reticulum (SR) that binds to the ryanodine receptor, calsequestrin, and triadin
1. This quaternary protein complex is thought to facilitate SR Ca2+ release. To
improve our understanding of the contribution of junctin to the regulation of SR
function, we examined the age-dependent effects of junctin overexpression in the
atrium of 3-, 6-, and 18-wk-old transgenic mice. The ratio of atrial weight and
body weight was unchanged between junctin-overexpressing (JCN) and wild-type
(WT) mice at all ages investigated (n=6-8). The protein expression of triadin 1
was decreased starting in 3-wk-old JCN atria (by 69%), whereas the expression of
the ryanodine receptor was diminished in 6- (by 48%) and 18-wk-old (by 57%) JCN
atria compared with age-matched WT atria. Force of contraction was decreased by
35% in 18-wk-old JCN compared with age-matched WT left atrial muscle strips,
which was accompanied by a prolonged time of relaxation (48.1 +/- 0.9 vs. 44.2
+/- 0.8 ms, respectively, n=6-8, P <0.05). The spontaneous beating rate of
isolated right atria was higher in 18-wk-old JCN mice compared with age-matched
WT mice (389 +/- 10 vs. 357 +/- 6 beats/min, respectively, n=6-8, P <0.05).
Heart rate was lower by 9% in telemetric ECG recordings in 18-wk-old JCN mice
during stress tests. Three-week-old JCN atria exhibited a higher potentiation of
force of contraction at rest pauses of 30 s (by 13%) and of 300 s (by 35%),
suggesting increased SR Ca2+ content. This was consistent with the higher force
of contraction in 3-wk-old JCN atria (by 29%) compared with age-matched WT atria
(by 10%) under the administration of caffeine. We conclude that in 3-wk-old
atria, junctin overexpression was associated with a reduced expression of
triadin 1 resulting in a higher SR Ca2+ load without changes in contractility or
heart rate. In 6-wk-old JCN atria, the compensatory downregulation of the
ryanodine receptor may offset the effects of junctin overexpression. Finally,
the progressive decrease in ryanodine receptor density may contribute to the
decreased atrial contractility and lower heart rate during stress in 18-wk-old
JCN mice. Calsequestrin, the major calcium sequestering protein in the sarcoplasmic
reticulum of muscle, forms a quaternary complex with the ryanodine receptor
calcium release channel and the intrinsic membrane proteins triadin and junctin.
We have investigated the possibility that calsequestrin is a luminal calcium
concentration sensor for the ryanodine receptor. We measured the luminal calcium
concentration at which calsequestrin dissociates from the ryanodine receptor and
the effect of calsequestrin on the response of the ryanodine receptor to changes
in luminal calcium. We provide electrophysiological and biochemical evidence
that: 1), luminal calcium concentration of >/=4 mM dissociates calsequestrin
from junctional face membrane, whereas in the range of 1-3 mM calsequestrin
remains attached; 2), the association with calsequestrin inhibits ryanodine
receptor activity, but amplifies its response to changes in luminal calcium
concentration; and 3), under physiological calcium conditions (1 mM),
phosphorylation of calsequestrin does not alter its ability to inhibit native
ryanodine receptor activity when the anchoring proteins triadin and junctin are
present. These data suggest that the quaternary complex is intact in vivo, and
provides further evidence that calsequestrin is involved in the sarcoplasmic
reticulum calcium signaling pathway and has a role as a luminal calcium sensor
for the ryanodine receptor. In cardiac muscle, junctin forms a quaternary protein complex with the ryanodine
receptor (RyR), calsequestrin, and triadin 1 at the luminal face of the
junctional sarcoplasmic reticulum (jSR). By binding directly the RyR and
calsequestrin, junctin may mediate the Ca(2+)-dependent regulatory interactions
between both proteins. To gain more insight into the underlying mechanisms of
impaired contractile relaxation in transgenic mice with cardiac-specific
overexpression of junctin (TG), we studied cellular Ca(2+) handling in these
mice. We found that the SR Ca(2+) load was reduced by 22% in cardiomyocytes from
TG mice. Consistent with this, the frequency of Ca(2+) sparks was diminished by
32%. The decay of spontaneous Ca(2+) sparks was prolonged by 117% in TG. This
finding was associated with a lower Na(+)-Ca(2+) exchanger (NCX) protein
expression (by 67%) and a higher basal RyR phosphorylation at Ser(2809) (by 64%)
in TG. The shortening- and Delta[Ca](i)-frequency relationships (0.5-4 Hz) were
flat in TG compared to wild-type (WT) which exhibited a positive staircase for
both parameters. Furthermore, increasing stimulation frequencies hastened the
time of relaxation and the decay of [Ca](i) by a higher percentage in TG. We
conclude that the impaired relaxation in TG may result from a reduced NCX
expression and/or a higher SR Ca(2+) leak. The altered shortening-frequency
relationship in TG seems to be a consequence of an impaired
excitation-contraction coupling with depressed SR Ca(2+) release at higher rates
of stimulation. Our data suggest that the more prominent frequency-dependent
hastening of relaxation in TG results from a stimulation of SR Ca(2+) transport
reflected by corresponding changes of [Ca](i). Triadin and junctin are integral sarcoplasmic reticulum membrane proteins that
form a macromolecular complex with the skeletal muscle ryanodine receptor (RyR1)
but their roles in skeletal muscle calcium homeostasis remain incompletely
understood. Here we report that delivery of siRNAs specific for triadin or
junctin into C2C12 skeletal myoblasts reduced the expression of triadin and
junctin in 8-day-old myotubes by 80 and 100%, respectively. Knocking down either
triadin or junctin in these cells reduced Ca2+ release induced by depolarization
(10mM KCl) by 20-25%. Unlike triadin knockdown myotubes, junctin knockdown and
junctin/triadin double knockdown myotubes also had reduced Ca2+ release induced
by 400 microM 4-chloro-m-cresol, 10mM caffeine, 400 microM UTP, or 1 microM
thapsigargin. Thus, knocking down junctin compromised the Ca2+ stores in the
sarcoplasmic reticulum of these cells. Our subsequent studies showed that in
junctin knockdown myotubes at least two sarcoplasmic reticulum proteins (RyR1
and skeletal muscle calsequestrin) were down-regulated while these proteins'
mRNA expression was not affected. The results suggest that triadin has a role in
facilitating KCl depolarization-induced Ca2+ release in contrast to junctin
which has a role in maintaining sarcoplasmic reticulum Ca2+ store size in C2C12
myotubes. Junctin, a 26 kDa intra-sarcoplasmic reticulum (SR) protein, forms a quaternary
complex with triadin, calsequestrin and the ryanodine receptor (RyR) at the
junctional SR membrane. The physiological role for junctin in the luminal
regulation of RyR Ca(2+) release remains unresolved, but it appears to be
essential for proper cardiac function since ablation of junctin results in
increased ventricular automaticity. Given that the junctin levels are severely
reduced in human failing hearts, we performed an in-depth study of the
mechanisms affecting intracellular Ca(2+) homeostasis in junctin-deficient
cardiomyocytes. In concurrence with sparks, JCN-KO cardiomyocytes display
increased Ca(2+) transient amplitude, resulting from increased SR [Ca(2+)]
([Ca(2+)](SR)). Junctin ablation appears to affect how RyRs 'sense' SR Ca(2+)
load, resulting in decreased diastolic SR Ca(2+) leak despite an elevated
[Ca(2+)](SR). Surprisingly, the β-adrenergic enhancement of [Ca(2+)](SR)
reverses the decrease in RyR activity and leads to spontaneous Ca(2+) release,
evidenced by the development of spontaneous aftercontractions. Single channel
recordings of RyRs from WT and JCN-KO cardiac SR indicate that the absence of
junctin produces a dual effect on the normally linear response of RyRs to
luminal [Ca(2+)]: at low luminal [Ca(2+)] (<1 mmol l(-1)), junctin-devoid RyR
channels are less responsive to luminal [Ca(2+)]; conversely, high luminal
[Ca(2+)] turns them hypersensitive to this form of channel modulation. Thus,
junctin produces complex effects on Ca(2+) sparks, transients, and leak, but the
luminal [Ca(2+)]-dependent dual response of junctin-devoid RyRs demonstrates
that junctin normally acts as an activator of RyR channels at low luminal
[Ca(2+)], and as an inhibitor at high luminal [Ca(2+)]. Because the crossover
occurs at a [Ca(2+)](SR) that is close to that present in resting cells, it is
possible that the activator-inhibitor role of junctin may be exerted under
periods of prevalent parasympathetic and sympathetic activity, respectively. RATIONALE: Catecholaminergic polymorphic ventricular tachycardia is an inherited
disease that predisposes to cardiac arrest and sudden death. The disease is
associated with mutations in the genes encoding for the cardiac ryanodine
receptor (RyR2) and cardiac calsequestrin (CASQ2). CASQ2 mutations lead to a
major loss of CASQ2 monomers, possibly because of enhanced degradation of the
mutant protein. The decrease of CASQ2 is associated with a reduction in the
levels of Triadin (TrD) and Junctin (JnC), two proteins that form, with CASQ2
and RyR2, a macromolecular complex devoted to control of calcium release from
the sarcoplasmic reticulum.
OBJECTIVE: We intended to evaluate whether viral gene transfer of wild-type
CASQ2 may rescue the broad spectrum of abnormalities caused by mutant CASQ2.
METHODS AND RESULTS: We used an adeno-associated serotype 9 viral vector to
express a green fluorescent protein-tagged CASQ2 construct. Twenty weeks after
intraperitoneal injection of the vector in neonate CASQ2 KO mice, we observed
normalization of the levels of calsequestrin, triadin, and junctin, rescue of
electrophysiological and ultrastructural abnormalities caused by CASQ2 ablation,
and lack of life-threatening arrhythmias.
CONCLUSIONS: We have proven the concept that induction of CASQ2 expression in
knockout mice reverts the molecular, structural, and electric abnormalities and
prevents life-threatening arrhythmias in CASQ2-defective catecholaminergic
polymorphic ventricular tachycardia mice. These data support the view that
development of CASQ2 viral gene transfer could have clinical application. Calsequestrin (CSQ) is a Ca(2+) storage protein that interacts with triadin
(TRN), the ryanodine receptor (RyR), and junctin (JUN) to form a macromolecular
tetrameric Ca(2+) signaling complex in the cardiac junctional sarcoplasmic
reticulum (SR). Heart-specific overexpression of CSQ in transgenic mice
(TG(CSQ)) was associated with heart failure, attenuation of SR Ca(2+) release,
and downregulation of associated junctional SR proteins, e.g., TRN. Hence, we
tested whether co-overexpression of CSQ and TRN in mouse hearts (TG(CxT)) could
be beneficial for impaired intracellular Ca(2+) signaling and contractile
function. Indeed, the depressed intracellular Ca(2+) concentration ([Ca](i))
peak amplitude in TG(CSQ) was normalized by co-overexpression in TG(CxT)
myocytes. This effect was associated with changes in the expression of cardiac
Ca(2+) regulatory proteins. For example, the protein level of the L-type Ca(2+)
channel Ca(v)1.2 was higher in TG(CxT) compared with TG(CSQ). Sarco(endo)plasmic
reticulum Ca(2+)-ATPase 2a (SERCA2a) expression was reduced in TG(CxT) compared
with TG(CSQ), whereas JUN expression and [(3)H]ryanodine binding were lower in
both TG(CxT) and TG(CSQ) compared with wild-type hearts. As a result of these
expressional changes, the SR Ca(2+) load was higher in both TG(CxT) and TG(CSQ)
myocytes. In contrast to the improved cellular Ca(2+), transient
co-overexpression of CSQ and TRN resulted in a reduced survival rate, an
increased cardiac fibrosis, and a decreased basal contractility in catheterized
mice, working heart preparations, and isolated myocytes. Echocardiographic and
hemodynamic measurements revealed a depressed cardiac performance after
isoproterenol application in TG(CxT) compared with TG(CSQ). Our results suggest
that co-overexpression of CSQ and TRN led to a normalization of the SR Ca(2+)
release compared with TG(CSQ) mice but a depressed contractile function and
survival rate probably due to cardiac fibrosis, a lower SERCA2a expression, and
a blunted response to β-adrenergic stimulation. Thus the TRN-to-CSQ ratio is a
critical modulator of the SR Ca(2+) signaling. |
What kind of chromatography is HILIC? | Hydrophilic Interaction Chromatography (HILIC) | Uric acid is the end-product of purine metabolism and a major antioxidant in
humans. The concentrations of uric acid in plasma and urine are associated with
various diseases and routinely measured in clinical and biomedical laboratories
using enzymatic conversion and colorimetric measurement. In this study a
hydrophilic interaction chromatographic (HILIC) method was developed for
simultaneous determination of uric acid and creatinine, a biomarker of urine
dilution and renal function, in human urine. Urine samples were pretreated by
dilution, protein precipitation, centrifugation and filtration. Uric acid and
creatinine were separated from other components in urine samples and quantified
using HILIC chromatography. A linear relationship between the ratio of the peak
area of the standards to that of the internal standard and the concentration of
the standards was obtained for both uric acid and creatinine with the square of
correlation coefficients >0.999 for both analytes. The detection limits were
0.04 μg/mL for creatinine and 0.06 μg/mL for uric acid. The described HILIC
method has proved to be simple, accurate, robust and reliable. For the analysis of highly hydrophilic and polar compounds, Hydrophilic
Interaction Chromatography (HILIC) has been established as a valuable
complementary approach to reversed-phase liquid chromatography (RPLC). Moreover,
the use of mobile phases with a high percentage of organic solvent in HILIC
separation is beneficial for mass spectrometric (MS) detection, because of
enhanced ionization which results in an increased sensitivity. In this review,
various applications of HILIC are described for a number of environmental and
food contamits together with detailed methodological descriptions and the
advantages or drawbacks of HILIC compared to other LC methods are critically
discussed. In the first part of the review, an overview is given of the work
that has been carried out with HILIC for the analysis of pharmaceuticals and
pesticides in environmental samples. HILIC has shown its applicability for polar
pharmaceuticals, such as antibiotics, estrogens and their metabolites, drugs of
abuse, cytostatics, metformin and contrast agents. In the pesticide group, HILIC
chromatography was helpful for polar phenylurea and organophosphorus pesticides.
The second part of the review focuses on the analysis of antibiotic residues in
food and feed with HILIC, while in the pesticide group, HILIC experiments have
been reported for dithiocarbamates and quaternary ammonium compounds. The last
chapter gives an overview of the analysis by HILIC of miscellaneous analytes in
aquatic and food/feed samples. BACKGROUND: In bioanalysis, phospholipids may affect the precision and accuracy
of LC-MS/MS methods and compromise the quality of the results, especially when
samples in complex biomatrices are extracted by protein precipitation
techniques.
RESULTS: It was found that the retentive behavior of both common pharmaceuticals
and physiologically relevant phospholipids under bare silica
hydrophilic-interaction LC (HILIC) is more predictable than under reversed-phase
conditions. In particular, the retention time of phospholipids was not
significantly affected by varying the salt and acid modifiers in the mobile
phases, but common pharmaceuticals can be shifted away from these phospholipid
interferences through mobile phase modifiers. Several mass spectrometric
techniques were applied to confirm this finding.
CONCLUSION: HILIC chromatography is a valued tool in the development of robust
bioanalytical assays with minimal and predictable phospholipid interferences.
Furthermore, addition of a small amount of ion-pairing additives can reliably
move pharmaceutical compounds away from these suppressive regions. Hydrophilic-interaction liquid chromatography (HILIC) is a widely used technique
for small polar molecule analysis and offers the advantage of improved
sensitivity in mass spectrometry. Although HILIC is today frequently employed as
an orthogonal fractionation method for peptides during the proteomic discovery
phase, it is still seldom considered for quantification. In this study, the
performances in terms of peak capacity and sensitivity of 3 HILIC columns were
compared to traditional reversed phase liquid C(18) column in the context of
targeted quantification of proteotypic peptides using selected reaction
monitoring mode (SRM). The results showed that the maximum sensitivity in HILIC
chromatography was achieved by using an amide column without salt buffer and
that the signal increased compared to classic reversed phase chromatography.
However, the intensity improvement is quite low compared to the one obtained for
small molecules. This is due on one hand to a higher matrix effect in HILIC and
on the other hand to a change of charge states of peptides in organic solvent
(doubly charged to monocharged). The doubly charged ions can be more readily
dissociated than singly charged ions, making them ideal for SRM peptide
quantification. As a result "supercharging" reagents are added to the mobile
phase to shift from predomit singly charged ions to the more favorable doubly
charged species. Using such optimized conditions, peptide signal is improved by
a factor of between two and ten for 88% of the peptides of the 81 peptides
investigated. A hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC
LC-MS/MS) method was developed and validated to simultaneously quantify six
aqueous choline-related compounds and eight major phospholipids classes in a
single run. HILIC chromatography was coupled to positive ion electrospray mass
spectrometry. A combination of multiple scan modes including precursor ion scan,
neutral loss scan and multiple reaction monitoring was optimized for the
determination of each compound or class in a single LC/MS run. This work
developed a simplified extraction scheme in which both free choline and related
compounds along with phospholipids were extracted into a homogenized phase using
chloroform/methanol/water (1:2:0.8) and diluted into methanol for the analysis
of target compounds in a variety of sample matrices. The analyte recoveries were
evaluated by spiking tissues and food samples with two isotope-labeled internal
standards, PC-d(3) and Cho-d(3). Recoveries of between 90% and 115% were
obtained by spiking a range of sample matrices with authentic standards
containing all 14 of the target analytes. The precision of the analysis ranged
from 1.6% to 13%. Accuracy and precision was comparable to that obtained by
quantification of selected phospholipid classes using (31)P NMR. A variety of
sample matrices including egg yolks, human diets and animal tissues were
analyzed using the validated method. The measurements of total choline in
selected foods were found to be in good agreement with values obtained from the
USDA choline database. |
What is the effect of TRH on myocardial contractility? | TRH improves myocardial contractility | Thyrotropin-releasing hormone (TRH) improved mean arterial pressure (MAP) and
myocardial contractility (dp/dtmax, -dp/dtmax, Vpm, and Vmax) and increased
plasma epinephrine levels significantly at 10 min after TRH treatment in rabbits
following shock, but the effects of TRH on MAP and myocardial contractility
disappeared in reserpinized rabbits (4 mg/kg, 24 hr pre-treatment, iv). TRH had
no effect on myocardial contractility and MAP at 20 and 30 min post-treatment in
rabbits pre-treated with the beta adrenergic blocker propranolol (1 mg/kg, 1 hr
before TRH treatment, iv), but the alpha adrenergic blocker phenoxybenzamine did
not affect these responses to TRH. Experiments in vitro show that although TRH
(10(-3) to 10(-8) M) had no direct effects on the isolated heart, left atrium,
and aortic strip, it did potentiate the inotropic effects of isoprenaline and
dopamine on the left atrium. These results suggest that the antishock effects of
TRH are related to adrenergic systems, perhaps acting on the sympathomedullary
system to secrete epinephrine and sensitize the beta receptors, but not alpha
receptors. Thus, TRH improves cardiac contractility, cardiac output, and
hemodynamics during hemorrhagic shock. The sensitization of the beta adrenergic
and dopamine receptors may play an important role in the direct peripheral
cardiovascular mechanism of TRH effects. Thyrotropin-releasing hormone (TRH) could improve mean arterial pressure (MAP),
myocardial contractile parameters (+/- dp/dtmax, Vpm and Vmax) and increase
plasma epinephrine level significantly at 10 min after TRH administration in
hemorrhagic shock rabbits, but the action of TRH on MAP and the myocardial
contractility did not appear in rabbits pre-treated with reserpine (4 mg/kg, 24
h pre-treatment, i.v.). TRH had no effects on myocardial contractility and MAP
at 20 and 30 min after administration to rabbits pre-treated with
beta-adrenergic blocker propranolol (1 mg/kg, 1 h before TRH injection i.v.),
but it did exert effects on these parameters in rabbits pre-treated with
alpha-adrenergic blocker phenoxybenzamine. Experiments in vitro showed that,
although TRH (10(-4) M/L) had no direct effect on heart, left atrium and aortic
strip, it did potentiate the inotropic effects of isoprenaline and dopamine on
the left atrium. These results suggested that antishock effect of TRH is related
to adrenergic system. TRH stimulates sympathomedullary system to secrete
epinephrine and sensitize the beta-receptors, but not alpha-receptors. Thus, TRH
improves cardiac contractility, cardiac output and hemodynamics during
hemorrhagic shock. The sensitization of the beta- and dopamine receptors played
an important role in producing direct peripheral actions of TRH. The effects of thyrotropin releasing hormone (TRH) on the contractility of
electrically stimulated and perfused isolated rat hearts were investigated. TRH
in the range of 0.1-10 mumol/l was found to exert a positive inotropic effect on
cardiac contractility, which however qualitatively differed at lower vs. higher
concentrations of the hormone: at 1 mumol/l, TRH was found to significantly
enhance the rate of contraction as well as that of relaxation (by 23.2 +/- 3.7
and 27.8 +/- 7.7%, respectively), which culminated in an increased peak
contractile force. However, at 10 mumol/l, the positive inotropic effect of TRH
(i.e. the increase in peak contractile force) was smaller than at 1 mumol/l,
which apparently was due to both a reduced TRH-induced elevation in the rate of
contraction (12.4 +/- 3.2%) and a TRH-induced decrease in relaxation rate (11.1
+/- 8.1%). Since TRH is expressed in the heart, the above findings suggest that,
in addition to its CNS-mediated cardiovascular effects, TRH modulates cardiac
contractility as an autocrine regulator in a concentration-dependent manner,
which likely involves more than one TRH receptor and associated signaling
pathway. Thyrotropin-releasing hormone (TRH) and its mRNA have been identified in the rat
heart, and TRH can enhance cardiomyocyte contractility in vivo. At present,
little is known about cardiac TRH gene transcriptional regulation in the heart.
Hormones and neurotransmitters, including thyroid hormone (T3), glucocorticoids,
testosterone, and 5-HT initiate effects not only in the cardiovascular system,
but also in the regulation of hypothalamic TRH. To clarify the potential roles
of these modulators upon the cardiac TRH gene transcription, rat TRH promoter
activity was assessed in rat embryonic myocyte cells (H9C2) by transient
transfection assays. TRH promoter activity was stimulated significantly by
dexamethasone (10(-4) M) and testosterone (10(-5) M), and was inhibited by T3
(10(-7) M). Interestingly, the neurotransmitter 5-HT stimulated TRH promoter
activity in H9C2 cells, but not in HTB-11 cells. To further clarify this
selective role of 5-HT on TRH promoter transcriptional activity in cardiac
cells, 5-HT receptor antagonists and agonists were tested. A selective 5-HT2
receptor antagonist blocked 5-HT stimulation, whereas 5-HT agonist analogs
caused augmentative effects when combined with 5-HT. Neither 5-HT nor any
antagonists or agonists influenced H9C2 cell growth or morphology. These data
suggest that 5-HT is an important transcriptional regulator of the cardiac TRH
gene. BACKGROUND: We reported previously that left ventricular gene expression for
thyrotropin-releasing hormone (TRH) precursor was increased in rats with heart
failure 8 weeks after myocardial infarction (MI) and that early ACE inhibition
tended to cause further myocardial induction of this gene.
METHODS AND RESULTS: Here, we show that after MI, the expression of pro-TRH is
induced in the heart coordinately with the protease PC1, an important enzyme in
TRH biosynthesis. Pro-TRH gene expression was induced in cardiac interstitial
cells after MI, and this effect was restricted to the heart, because no increase
in TRH mRNA abundance was observed in the hypothalamus, kidney, or lung.
Transcript abundance of pro-TRH can be increased in cultured cardiac fibroblasts
by several adrenergic agonists, indicating that the adrenergic axis may play a
regulatory role in cardiac TRH production. Acute intravenous administration of
TRH to rats with ischemic cardiomyopathy caused a significant increase in heart
rate, mean arterial pressure, cardiac output, stroke volume, and cardiac
contractility.
CONCLUSIONS: Taken together, these results indicate that TRH is specifically
induced in the heart after MI and that it can increase cardiac performance in
rats with ischemic cardiomyopathy. Thus, in addition to catecholamine and
angiotensin II, pro-TRH/TRH may be another important axis that affects
hemodynamics and cardiac function in heart failure. |
Proteomic analyses need prior knowledge of the organism complete genome. Is the complete genome of the bacteria of the genus Arthrobacter available? | Yes, the complete genome sequence of Arthrobacter (two strains) is deposited in GenBank. | Arthrobacter phethrenivorans is the type species of the genus, and is able to
metabolize phethrene as a sole source of carbon and energy. A.
phethrenivorans is an aerobic, non-motile, and Gram-positive bacterium,
exhibiting a rod-coccus growth cycle which was originally isolated from a
creosote polluted site in Epirus, Greece. Here we describe the features of this
organism, together with the complete genome sequence, and annotation. Arthrobacter sp. B6 is a Gram-positive, non-motile, facultative aerobic
bacterium, isolated from the arsenic-contaminated aquifer sediment in the Datong
basin, China. This strain displays high resistance to arsenic, and can
dynamically transform arsenic under aerobic condition. Here, we described the
high quality draft genome sequence, annotations and the features of Arthrobacter
sp. B6. The G + C content of the genome is 64.67%. This strain has a genome size
of 4,663,437 bp; the genome is arranged in 8 scaffolds that contain 25 contigs.
From the sequences, 3956 protein-coding genes, 264 pseudo genes and 89
tRNA/rRNA-encoding genes were identified. The genome analysis of this strain
helps to better understand the mechanism by which the microbe efficiently
tolerates arsenic in the arsenic-contaminated environment. Author information:
(1)State Key Laboratory of Urban Water Resource and Environment, Harbin
Institute of Technology, 150090, Harbin, China; Section of Sanitary Engineering,
Department of Water Management, Delft University of Technology, 2628CN, Delft,
The Netherlands.
(2)State Key Laboratory of Urban Water Resource and Environment, Harbin
Institute of Technology, 150090, Harbin, China.
(3)Section of Sanitary Engineering, Department of Water Management, Delft
University of Technology, 2628CN, Delft, The Netherlands.
(4)State Key Laboratory of Urban Water Resource and Environment, Harbin
Institute of Technology, 150090, Harbin, China. Electronic address:
[email protected].
(5)State Key Laboratory of Urban Water Resource and Environment, Harbin
Institute of Technology, 150090, Harbin, China. Electronic address:
[email protected]. Author information:
(1)Department of Applied Chemistry, Graduate School of Engineering, University
of Hyogo, Himeji, Hyogo, Japan.
(2)Graduate School of Science and Engineering, Kagoshima University, Korimoto,
Kagoshima, Japan.
(3)Department of Applied Chemistry, Graduate School of Engineering, University
of Hyogo, Himeji, Hyogo, Japan [email protected]. Author information:
(1)Department of Biology, University of Florence, Florence, Italy.
(2)Department of Experimental and Clinical Medicine, University of Florence,
Florence, Italy.
(3)Center for Integrative Medicine, Careggi University Hospital, University of
Florence, Florence, Italy.
(4)Department of Surgery and Translational Medicine, University of Florence,
Florence, Italy.
(5)Clinical Microbiology and Virology Unit, Careggi University Hospital,
Florence, Italy.
(6)Department of Biology, University of Florence, Florence, Italy
[email protected]. Arthrobacter alpinus R3.8 is a psychrotolerant bacterial strain isolated from a
soil sample obtained at Rothera Point, Adelaide Island, close to the Antarctic
Peninsula. Strain R3.8 was sequenced in order to help discover potential cold
active enzymes with biotechnological applications. Genome analysis identified
various cold adaptation genes including some coding for anti-freeze proteins and
cold-shock proteins, genes involved in bioremediation of xenobiotic compounds
including naphthalene, and genes with chitinolytic and N-acetylglucosamine
utilization properties and also plant-growth-influencing properties. In this
genome report, we present a complete genome sequence of A. alpinus strain R3.8
and its annotation data, which will facilitate exploitation of potential novel
cold-active enzymes. |
What is the structural fold of bromodomain proteins? | The structure fold of the bromodomains is an all-alpha-helical fold, which includes a left-handed four-helix bundle topology, with two short additional helices in a long connecting loop. | Histone acetylation is important in chromatin remodelling and gene activation.
Nearly all known histone-acetyltransferase (HAT)-associated transcriptional
co-activators contain bromodomains, which are approximately 110-amino-acid
modules found in many chromatin-associated proteins. Despite the wide occurrence
of these bromodomains, their three-dimensional structure and binding partners
remain unknown. Here we report the solution structure of the bromodomain of the
HAT co-activator P/CAF (p300/CBP-associated factor). The structure reveals an
unusual left-handed up-and-down four-helix bundle. In addition, we show by a
combination of structural and site-directed mutagenesis studies that
bromodomains can interact specifically with acetylated lysine, making them the
first known protein modules to do so. The nature of the recognition of
acetyl-lysine by the P/CAF bromodomain is similar to that of acetyl-CoA by
histone acetyltransferase. Thus, the bromodomain is functionally linked to the
HAT activity of co-activators in the regulation of gene transcription. TFIID is a large multiprotein complex that initiates assembly of the
transcription machinery. It is unclear how TFIID recognizes promoters in vivo
when templates are nucleosome-bound. Here, it is shown that TAFII250, the
largest subunit of TFIID, contains two tandem bromodomain modules that bind
selectively to multiply acetylated histone H4 peptides. The 2.1 angstrom crystal
structure of the double bromodomain reveals two side-by-side, four-helix bundles
with a highly polarized surface charge distribution. Each bundle contains an
Nepsilon-acetyllysine binding pocket at its center, which results in a structure
ideally suited for recognition of diacetylated histone H4 tails. Thus, TFIID may
be targeted to specific chromatin-bound promoters and may play a role in
chromatin recognition. The solution structure of the bromodomain from the human transcriptional
coactivator GCN5 has been determined using NMR methods. The structure has a
left-handed four-helix bundle topology, with two short additional helices in a
long connecting loop. A hydrophobic groove and deep hydrophobic cavity are
formed by loops at one end of the molecule. NMR binding experiments show that
the cavity forms a specific binding pocket for the acetamide moiety. Peptides
containing an N(epsilon)-acetylated lysine residue bind in this pocket with
modest affinity (K(D) approximately 0.9 mM); no comparable binding occurs with
unacetylated peptides. The GCN5 bromodomain binds the small ligands
N(omega)-acetylhistamine and N-methylacetamide, confirming specificity for the
alkyl acetamide moiety and showing that the primary element of recognition is
simply the sterically unhindered terminal acetamide moiety of an acetylated
lysine residue. Additional experiments show that binding is enhanced if the
acetyl-lysine residue occurs within the context of a basic peptide and is
inhibited by the presence of nearby acidic residues and by the carboxyl group of
the free acetyl-lysine amino acid. The binding of the GCN5 bromodomain to
acetylated peptides appears to have little additional sequence dependence,
although weak interactions with other regions of the peptide are implicated by
the binding data. Discrimination between ligands of positive and negative charge
is attributed to the presence of several acidic residues located on the loops
that form the sides of the binding pocket. Unlike the residues forming the
acetamide binding cavity, these acidic side-chains are not conserved in other
bromodomain sequences, suggesting that bromodomains might display differences in
substrate selectivity and specificity as well as differences in function in
vivo. BRD7 is an important protein tightly associated with Nasopharyngeal carcinoma
(NPC). Overexpression of BRD7 inhibits NPC cell growth and cell cycle by
transcriptionally regulating the cell cycle related genes. BRD7 contains a
bromodomain that is found in many chromatin-associated proteins and in nearly
all known nuclear histone acetyltransferases (HATs) and plays an important role
in chromatin remodeling and transcriptional activation. Here, we report the
solution structure of BRD7 bromodomain determined by NMR spectroscopy, and its
binding specificity revealed by NMR titration with several acetylated histone
peptides. We find that BRD7 bromodomain contains the typical left-handed
four-helix bundle topology, and can bind with weak affinity to lysine-acetylated
peptides derived from histone H3 with K9 or K14 acetylated and from histone H4
with K8, K12 or K16 acetylated. Our results show that BRD7 bromodomain lacks
inherent binding specificity when binding to histones in vitro. Bromodomains represent an extensive family of evolutionarily conserved domains
that are found in many chromatin-associated proteins such as histone
acetyltransferases (HAT) and subunits of ATP-dependent chromatin-remodeling
complexes. These domains are associated with acetylated lysine residues that
bind both in vivo and in vitro; for example, they bind to the N-acetylated
lysines of the histone tail of nucleosomes. In this report, we determined the
structure of the bromodomain from human brahma-related gene 1 (BRG1) protein, a
subunit of an ATP-dependent switching/sucrose nonfermenting (SWI/SNF) remodeling
complex, and have also characterized its in vitro interaction with N-acetylated
lysine peptides from histones. In addition to a typical all-alpha-helical fold
that was observed in the bromodomains, we observed for the first time a small
beta-sheet in the ZA loop region of the BRG1 protein. The BRG1 bromodomain
exhibited binding, albeit weak, to acetylated peptides that were derived from
histones H3 and H4. We have compared the acetyl-lysine binding sites of BRG1
bromodomain with the yGCN5 (general control of amino acid biosynthesis). By
modeling the acetylated-lysine peptide into the BRG1 bromodomain structure, we
were able to explain the weak binding of acetylated-lysine peptides to this
bromodomain. BACKGROUND: Brd2 is a transcriptional regulator and belongs to BET family, a
less characterized novel class of bromodomain-containing proteins. Brd2 contains
two tandem bromodomains (BD1 and BD2, 46% sequence identity) in the N-terminus
and a conserved motif named ET (extra C-terminal) domain at the C-terminus that
is also present in some other bromodomain proteins. The two bromodomains have
been shown to bind the acetylated histone H4 and to be responsible for mitotic
retention on chromosomes, which is probably a distinctive feature of BET family
proteins. Although the crystal structure of Brd2 BD1 is reported, no structure
features have been characterized for Brd2 BD2 and its interaction with
acetylated histones.
RESULTS: Here we report the solution structure of human Brd2 BD2 determined by
NMR. Although the overall fold resembles the bromodomains from other proteins,
significant differences can be found in loop regions, especially in the ZA loop
in which a two amino acids insertion is involved in an uncommon pi-helix, termed
piD. The helix piD forms a portion of the acetyl-lysine binding site, which
could be a structural characteristic of Brd2 BD2 and other BET bromodomains.
Unlike Brd2 BD1, BD2 is monomeric in solution. With NMR perturbation studies, we
have mapped the H4-AcK12 peptide binding interface on Brd2 BD2 and shown that
the binding was with low affinity (2.9 mM) and in fast exchange. Using NMR and
mutational analysis, we identified several residues important for the Brd2
BD2-H4-AcK12 peptide interaction and probed the potential mechanism for the
specific recognition of acetylated histone codes by Brd2 BD2.
CONCLUSION: Brd2 BD2 is monomeric in solution and dynamically interacts with
H4-AcK12. The additional secondary elements in the long ZA loop may be a common
characteristic of BET bromodomains. Surrounding the ligand-binding cavity, five
aspartate residues form a negatively charged collar that serves as a secondary
binding site for H4-AcK12. We suggest that Brd2 BD1 and BD2 may possess
distinctive roles and cooperate to regulate Brd2 functions. The structure basis
of Brd2 BD2 will help to further characterize the functions of Brd2 and its BET
members. |
List the endoscopic diagnoses that have been reported in children with autism | Endoscopic examinations in autistic children have been reported to show : I or II reflux esophagitis, Achalasia, chronic gastritis and chronic duodenitis, mild acute and chronic inflammation of the small bowel and colorectum and Ileo-colonic lymphoid nodular hyperplasia (LNH).
The number of Paneth's cells in the duodenal crypts was found to be significantly elevated in autistic children compared with non-autistic control subjects. Low intestinal carbohydrate digestive enzyme activity was reported although there was no abnormality found in pancreatic function. Autistic children have ben reported to have an increased pancreatico-biliary fluid output after intravenous secretin administration. | We report three children with autistic spectrum disorders who underwent upper
gastrointestinal endoscopy and intravenous administration of secretin to
stimulate pancreaticobiliary secretion. All three had an increased
pancreaticobiliary secretory response when compared with nonautistic patients
(7.5 to 10 mL/min versus 1 to 2 mL/min). Within 5 weeks of the secretin
infusion, a significant amelioration of the children's gastrointestinal symptoms
was observed, as was a dramatic improvement in their behavior, manifested by
improved eye contact, alertness, and expansion of expressive language. These
clinical observations suggest an association between gastrointestinal and brain
function in patients with autistic behavior. OBJECTIVES: Our aim was to evaluate the structure and function of the upper
gastrointestinal tract in a group of patients with autism who had
gastrointestinal symptoms.
STUDY DESIGN: Thirty-six children (age: 5.7 +/- 2 years, mean +/- SD) with
autistic disorder underwent upper gastrointestinal endoscopy with biopsies,
intestinal and pancreatic enzyme analyses, and bacterial and fungal cultures.
The most frequent gastrointestinal complaints were chronic diarrhea,
gaseousness, and abdominal discomfort and distension.
RESULTS: Histologic examination in these 36 children revealed grade I or II
reflux esophagitis in 25 (69.4%), chronic gastritis in 15, and chronic
duodenitis in 24. The number of Paneth's cells in the duodenal crypts was
significantly elevated in autistic children compared with non-autistic control
subjects. Low intestinal carbohydrate digestive enzyme activity was reported in
21 children (58.3%), although there was no abnormality found in pancreatic
function. Seventy-five percent of the autistic children (27/36) had an increased
pancreatico-biliary fluid output after intravenous secretin administration.
Nineteen of the 21 patients with diarrhea had significantly higher fluid output
than those without diarrhea.
CONCLUSIONS: Unrecognized gastrointestinal disorders, especially reflux
esophagitis and disaccharide malabsorption, may contribute to the behavioral
problems of the non-verbal autistic patients. The observed increase in
pancreatico-biliary secretion after secretin infusion suggests an upregulation
of secretin receptors in the pancreas and liver. Further studies are required to
determine the possible association between the brain and gastrointestinal
dysfunctions in children with autistic disorder. OBJECTIVES: A relationship between autism and gastrointestinal (GI) immune
dysregulation has been postulated based on incidence of GI complaints as well as
macroscopically observed lymphonodular hyperplasia and microscopically
determined enterocolitis in pediatric patients with autism. To evaluate GI
immunity, we quantitatively assessed levels of proinflammatory cytokines,
interleukin (IL)-6, IL-8, and IL-1beta, produced by intestinal biopsies of
children with pervasive developmental disorders.
METHODS: Fifteen patients, six with pervasive developmental disorders and nine
age-matched controls, presenting for diagnostic colonoscopy were enrolled.
Endoscopic biopsies were organ cultured, supernatants were harvested, and IL-6,
IL-8, and IL-1beta levels were quantified by ELISA. Tissue histology was
evaluated by blinded pathologists.
RESULTS: Concentrations of IL-6 from intestinal organ culture supernatants of
patients with pervasive developmental disorders (median 318.5 pg/ml,
interquartile range 282.0-393.0 pg/ml) when compared with controls (median 436.9
pg/ml, interquartile range 312.6-602.5 pg/ml) were not significantly different
(p = 0.0987). Concentrations of IL-8 (median 84,000 pg/ml, interquartile range
16,000-143,000 pg/ml) when compared with controls (median 177,000 pg/ml,
interquartile range 114,000-244,000 pg/ml) were not significantly different (p =
0.0707). Concentrations of IL-1beta (median 0.0 pg/ml, interquartile range
0.0-94.7 pg/ml) when compared with controls (median 0.0 pg/ml, interquartile
range 0.0-60.2 pg/ml) were not significantly different (p = 0.8826). Tissue
histology was nonpathological for all patients.
CONCLUSIONS: We have demonstrated no significant difference in production of
IL-6, IL-8, and IL-1beta between patients with pervasive developmental disorders
and age-matched controls. In general, intestinal levels of IL-6 and IL-8 were
lower in patients with pervasive developmental disorders than in age-matched
controls. These data fail to support an association between autism and GI
inflammation. BACKGROUND: Intestinal mucosal pathology, characterized by ileo-colonic lymphoid
nodular hyperplasia (LNH) and mild acute and chronic inflammation of the
colorectum, small bowel and stomach, has been reported in children with autistic
spectrum disorder (ASD).
AIM: To assess ileo-colonic LNH in ASD and control children and to test the
hypothesis that there is an association between ileo-colonic LNH and ASD in
children.
PATIENTS AND METHODS: One hundred and forty-eight consecutive children with ASD
(median age 6 years; range 2-16; 127 male) with gastrointestinal symptoms were
investigated by ileo-colonoscopy. Macroscopic and histological features were
scored and compared with 30 developmentally normal (non-inflammatory bowel
disease, non-coeliac disease) controls (median age 7 years; range 1-11; 25 male)
showing mild non-specific colitis in 16 cases (13 male) and normal colonic
histology in 14 cases (12 male). Seventy-four ASD children and 23 controls also
underwent upper gastrointestinal endoscopy. The influence on ileal LNH of
dietary restriction, age at colonoscopy, and co-existent LNH elsewhere in the
intestine, was examined.
RESULTS: The prevalence of LNH was significantly greater in ASD children
compared with controls in the ileum (129/144 (90%) vs. 8/27 (30%), P < 0.0001)
and colon (88/148 (59%) vs. 7/30 (23%), P = 0.0003), whether or not controls had
co-existent colonic inflammation. The severity of ileal LNH was significantly
greater in ASD children compared with controls, with moderate to severe ileal
LNH present in 98 of 144 (68%) ASD children versus 4 of 27 (15%) controls (P <
0.0001). Severe ileal LNH was associated with co-existent colonic LNH in ASD
children (P = 0.01). The presence and severity of ileal LNH was not influenced
by either diet or age at colonoscopy (P = 0.2). Isolated ileal LNH without
evidence of pathology elsewhere in the intestine was a rare event, occurring in
less than 3% of children overall. On histopathological examination, hyperplastic
lymphoid follicles are significantly more prevalent in the ileum of ASD children
(84/138; 61%) compared with controls (2/23; 9%, P = 0.0001).
CONCLUSION: Ileo-colonic LNH is a characteristic pathological finding in
children with ASD and gastrointestinal symptoms, and is associated with mucosal
inflammation. Differences in age at colonoscopy and diet do not account for
these changes. The data support the hypothesis that LNH is a significant
pathological finding in ASD children. Chronic gastrointestinal symptoms are commonly reported in autistic patients.
Dysphagia is often present, and it is generally related to behavioral eating
disorders. The association between autism and esophageal achalasia has not been
described in literature yet. We report our experience with three cases of
autistic children we recently treated for esophageal achalasia. In the first
case (a 14-year-old male), achalasia was diagnosed with barium swallow and
esophageal manometry and was successfully treated with three pneumatic
endoscopic dilatations (follow-up: 3 years). In the second case (a 12-year-old
female), achalasia was diagnosed with barium swallow and esophageal manometry
and was treated with Heller myotomy after two unsuccessful pneumatic endoscopic
attempts (follow-up: 3 months). In the last case, a 15-year-old male underwent
barium swallow and endoscopy that confirmed achalasia. He was treated with
Heller myotomy, and he is asymptomatic at a 6-month follow-up. To our knowledge,
this is the first report of a possible association between autism and esophageal
achalasia. Because of the rarity of both diseases, their association in the same
patient is unlikely to be casual even if speculation on their common etiology is
impossible at present. This finding needs further confirmation, but it is
sufficient, in our opinion, to indicate proper evaluation with barium swallow
and/or manometry in any autistic children with eating difficulty. |
What are the outcomes of Renal sympathetic denervation? | Significant decreases and progressively higher reductions of systolic and diastolic blood pressure were observed after RSD. The complication rate was minimal.
Renal sympathetic denervation also reduces heart rate, which is a surrogate marker of cardiovascular risk. | Despite the considerable advances in the treatment of hypertension that have
been made over the past few decades, adequate management and control of this
condition remains poor, and efforts are ongoing to develop new strategies to
improve related outcomes. Novel therapeutic approaches to the management of
systemic hypertension fall into two major categories: (i) those that seek to
improve blood pressure-lowering efficacy using new therapeutic strategies in
addition to standard non-pharmacological and pharmacological approaches and (ii)
novel ways to optimize and improve the efficacy and utility of existing
therapies. Novel procedure- and device-based strategies to control hypertension
include renal sympathetic denervation and baroreflex sensitization. These two
techniques will be the focus of the present review. Hypertension represents a significant global public health concern, contributing
to vascular and renal morbidity, cardiovascular mortality, and economic burden.
The opportunity to influence clinical outcomes through hypertension management
is therefore paramount. Despite adherence to multiple available medical
therapies, a significant proportion of patients have persistent blood pressure
elevation, a condition termed resistant hypertension. Recent recognition of the
importance of the renal sympathetic and somatic nerves in modulating blood
pressure and the development of a novel procedure that selectively removes these
contributors to resistant hypertension represents an opportunity to provide
clinically meaningful benefit across wide and varied patient populations. Early
clinical evaluation with catheter-based, selective renal sympathetic denervation
in patients with resistant hypertension has mechanistically correlated
sympathetic efferent denervation with decreased renal norepinephrine spillover
and renin activity, increased renal plasma flow, and has demonstrated clinically
significant, sustained reductions in blood pressure. The SYMPLICITY HTN-3 Trial
is a pivotal study designed as a prospective, randomized, masked procedure,
single-blind trial evaluating the safety and effectiveness of catheter-based
bilateral renal denervation for the treatment of uncontrolled hypertension
despite compliance with at least 3 antihypertensive medications of different
classes (at least one of which is a diuretic) at maximal tolerable doses. The
primary effectiveness endpoint is measured as the change in office-based
systolic blood pressure from baseline to 6 months. This manuscript describes the
design and methodology of a regulatory trial of selective renal denervation for
the treatment of hypertension among patients who have failed pharmacologic
therapy. Systemic hypertension represents a significant global concern, because it
contributes to vascular and renal morbidity, cardiovascular mortality, and
economic burden, hence the impact of hypertension is a major issue in public
health worldwide. Improving high blood pressure management is therefore
fundamental to influencing clinical outcomes. Despite adherence to multiple
available medical therapies, a significant proportion of patients has persistent
blood pressure elevation, a condition termed "resistant hypertension". Renal
sympathetic innervations contribute to lack of response of anti-hypertensive
drugs through an imbalance of regulatory mechanisms. Renal afferent nerve fibers
are responsible for sympathetic activation and contribute to blood pressure
homeostasis while afferent signals from the kidneys are integrated at the
central nervous system and enhance sympathetic nerve discharge. In this regard,
a novel strategy that selectively removes these hypertensive contributors
represents a new therapeutic opportunity. Recently, a catheter-based method to
induce renal sympathetic denervation has been introduced into daily practice.
Clinical evaluation of selective renal sympathetic denervation demonstrated a
decrease of renal norepinephrine spillover and renin activity, an increase of
renal plasma flow, and has confirmed clinically significant, sustained
reductions in blood pressure in patients with resistant hypertension. This
review summarizes the available data on the role of sympathetic activation in
the pathophysiology of hypertension and the current concepts in transcatheter
renal artery ablation with radiofrequency delivery for systemic hypertension.
Suggestions regarding targets for future systemic hypertension management are
also described. Resistant hypertension is an increasingly prevalent health problem associated
with important adverse cardiovascular outcomes. The pathophysiology that
underlies this condition involves increased function of both the sympathetic
nervous system and the renin-angiotensin II-aldosterone system. A crucial link
between these 2 systems is the web of sympathetic fibres that course within the
adventitia of the renal arteries. These nerves can be targeted by applying
radiofrequency energy from the lumen of the renal arteries to renal artery walls
(percutaneous renal sympathetic denervation [RSD]), an approach that has
attracted great interest. This paper critically reviews the evidence supporting
the use of RSD. Small studies suggest that RSD can produce dramatic blood
pressure reductions: In the randomized Symplicity HTN-2 trial of 106 patients,
the mean fall in blood pressure at 6 months in patients who received the
treatment was 32/12 mm Hg. However, there are limitations to the evidence for
RSD in the treatment of resistant hypertension. These include the small number
of patients studied; the lack of any placebo-controlled evidence; the fact that
blood pressure outcomes were based on office assessments, as opposed to 24-hour
ambulatory monitoring; the lack of longer-term efficacy data; and the lack of
long-term safety data. Some of these concerns are being addressed in the ongoing
Renal Denervation in Patients With Uncontrolled Hypertension (Symplicity HTN-3)
trial. The first percutaneous RSD system was approved by Health Canada in the
spring of 2012. But until more and better-quality data are available, this
procedure should generally be reserved for those patients whose resistant
hypertension is truly uncontrolled. Renal afferent and efferent sympathetic nerves are involved in the regulation of
blood pressure and have a pathophysiological role in hypertension. Renal
sympathetic denervation is a novel therapeutic technique for the treatment of
patients with resistant hypertension. Clinical trials of renal sympathetic
denervation have shown significant reductions in blood pressure in these
patients. Renal sympathetic denervation also reduces heart rate, which is a
surrogate marker of cardiovascular risk. Conditions that are comorbid with
hypertension, such as heart failure and myocardial hypertrophy, obstructive
sleep apnoea, atrial fibrillation, renal dysfunction, and metabolic syndrome are
closely associated with enhanced sympathetic activity. In experimental models
and case-control studies, renal denervation has had beneficial effects on these
conditions. Renal denervation could become a commonly used procedure to treat
resistant hypertension and chronic diseases associated with enhanced sympathetic
activation. Current work is focused on refining the techniques and
interventional devices to provide safe and effective renal sympathetic
denervation. Controlled studies in patients with mild-to-moderate, nonresistant
hypertension and comorbid conditions such as heart failure, diabetes mellitus,
sleep apnoea, and arrhythmias are needed to investigate the capability of renal
sympathetic denervation to improve cardiovascular outcomes. 1. The authors review the concept of resistant hypertension and the involvement of
the sympathetic nervous system in hypertension as a rational basis for the
technique of renal sympathetic denervation (RSD) performed percutaneously. This
revision is the result of an active search for scientific articles with the term
"renal denervation" in the Medline and PubMed databases. The techniques and
devices used in the procedure are presented, as well as clinical outcomes at
six, 12 and 24 months after the intervention with the Symplicity catheter.
Significant decreases and progressively higher reductions of systolic and
diastolic blood pressure were observed after RSD. The complication rate was
minimal. New devices for RSD and its ongoing clinical studies are cited. In
conclusion, the RSD presents itself as an effective and safe approach to
resistant hypertension. Results from ongoing studies and longer follow-up of
these patients are expected to confirm the initial results and put into
perspective the expansion of the procedure use in hypertension approach. |
Which MAP kinase phosphorylates the transcription factor c-jun? | c-Jun is phosphorylated by c-Jun NH2-terminal kinase (JNK). | Tyrosine kinase growth factor receptors activate MAP kinase by a complex
mechanism involving the SH2/3 protein Grb2, the exchange protein Sos, and Ras.
The GTP-bound Ras protein binds to the Raf kinase and initiates a protein kinase
cascade that leads to MAP kinase activation. Three MAP kinase kinase kinases
have been described--c-Raf, c-Mos, and Mekk--that phosphorylate and activate
Mek, the MAP kinase kinase. Activated Mek phosphorylates and activates MAP
kinase. Subsequently, the activated MAP kinase translocates into the nucleus
where many of the physiological targets of the MAP kinase signal transduction
pathway are located. These substrates include transcription factors that are
regulated by MAP kinase phosphorylation (e.g., Elk-1, c-Myc, c-Jun, c-Fos, and
C/EBP beta). Thus the MAP kinase pathway represents a significant mechanism of
signal transduction by growth factor receptors from the cell surface to the
nucleus that results in the regulation of gene expression. Three MAP kinase
homologs have been identified in the rat: Erk1, Erk2, and Erk3. Human MAP
kinases that are similar to the rat Erk kinases have also been identified by
molecular cloning. The human Erk1 protein kinase has been shown to be widely
expressed as a 44-kDa protein in many tissues. The human Erk2 protein kinase is
a 41-kDa protein that is expressed ubiquitously. In contrast, a human
Erk3-related protein kinase has been found to be expressed at a high level only
in heart muscle and brain. The loci of these MAP kinase genes are widely
distributed within the human genome: erk2 at 22q11.2; erk1 at 16p11.2; and
ek3-related at 18q12-21. In the yeast Saccharomyces cerevisiae, five MAP kinase
gene homologs have been described: smkl, mpk1, hog1, fus3, and kss1. Together,
these kinases are a more diverse group than the human erks that have been
identified. Thus the erks are likely to represent only one subgroup of a larger
human MAP kinase gene family. A candidate for this extended family of MAP
kinases is the c-Jun NH2-terminal kinase (Jnk), which binds to and
phosphorylates the transcription factor c-Jun at the activating sites Ser-63 and
Ser-73. Evidence is presented here to demonstrate that Jnk is a distant relative
of the MAP kinase group that is activated by dual phosphorylation at Tyr and
Thr. In the CNS, astrocytes are significant sources of RANTES/CCL5 (regulated upon
activation, normal T cell expressed and secreted), a CC-chemokine with important
biological function. Astrocyte RANTES/CCL5 has been shown to be induced by
interleukin-1 (IL-1), with interferon-gamma (IFNgamma) as a primer, but whether
type I interferons play any role in the expression of RANTES/CCL5 is not known.
In this report, we studied the detailed mechanism of RANTES/CCL5 induction in
primary human astrocytes activated with IL-1 and IFNbeta. Ribonuclease
protection assay and ELISA showed that IFNbeta, although not effective alone,
increased IL-1-induced RANTES/CCL5 expression, but did not antagonize IFNgamma.
IL-1 or IL-1/IFNbeta-induced RANTES/CCL5 expression was inhibited by the
super-repressor IkappaBalpha or inhibitors of p38 or c-Jun N-terminal kinase
(JNK) MAPKs (mitogen-activated protein kinases), but not by extracellular signal
regulated kinases (ERK) inhibitors. IFNbeta enhanced IL-1-induced
phosphorylation of p38 MAPK, but was not effective alone. Transfection with
mutated RANTES/CCL5 promoter-reporter constructs revealed that kappaB,
interferon-stimulated response element (ISRE) and CAATT-enhancer binding
protein-beta (C/EBPbeta) sites all contributed to IL-1/IFNbeta-induced
RANTES/CCL5 transcription. IFNbeta synergized with IL-1 to induce nuclear
accumulation of C/EBPbeta protein. They also synergized to form nuclear ISRE
complexes with Stat1, Stat2 and interferon regulatory factor-1 (IRF-1) proteins.
Together, our results demonstrate that IFNbeta plays a positive regulatory role
in the expression of RANTES/CCL5 in human astrocytes through several distinct
mechanisms. c-Jun N-terminal kinases (JNKs) are a group of mitogen-activated protein kinase
family members that are important in regulating cell growth, proliferation, and
apoptosis. Activation of the JNK pathway has been implicated in the formation of
several human tumors. We have previously demonstrated that a 55-kDa JNK isoform
is constitutively activated in 86% of human brain tumors and more recently
demonstrated that this isoform is either JNK2alpha2 or JNK2beta2. Importantly,
we have also found that among the 10 known JNK isoforms, the JNK2 isoforms are
unique in their ability to autophosphorylate in vitro and in vivo. This does not
require the participation of any upstream kinases and also leads to substrate
kinase activity in vitro and in vivo. To clarify the mechanism of JNK2alpha2
autoactivation, we have generated a series of chimeric cDNAs joining portions of
JNK1alpha2, which does not have detectable autophosphorylation activity, with
portions of JNK2alpha2, which has the strongest autophosphorylation activity.
Through in vivo and in vitro kinase assays, we were able to define a domain
ranging from amino acids 218 to 226 within JNK2alpha2 that is required for its
autophosphorylation. Mutation of JNK2alpha2 to its counterpart of JNK1alpha2 in
this region abrogated the autophosphorylation activity and c-Jun substrate
kinase activity in vivo and in vitro. Notably, switching of JNK1alpha2 to
JNK2alpha2 at this 9-amino acid site enabled JNK1alpha2 to gain the
autophosphorylation activity in vivo and in vitro. We also found two other
functional sites that participate in JNK2alpha2 activity. One site ranging from
amino acids 363 to 382 of JNK2alpha2 is required for efficient c-Jun binding in
vitro, and a site ranging from amino acids 383 to 424 enhances
autophosphorylation intensity, although it is not required for triggering the
autophosphorylation in vitro. These findings have uncovered the regions required
for JNK2alpha2 autophosphorylation, and this information could be used as
potential targets to block JNK2alpha2 activation. The c-Jun N-terminal kinases (JNKs) are members of the mitogen-activated protein
kinase (MAPK) family and are activated by environmental stress. JNK is also
activated by proinflammatory cytokines, such as TNF and IL-1, and Toll-like
receptor ligands. This pathway, therefore, can act as a critical convergence
point in immune system signaling for both adaptive and innate responses. Like
other MAPKs, the JNKs are activated via the sequential activation of protein
kinases that includes two dual-specificity MAP kinase kinases (MKK4 and MKK7)
and multiple MAP kinase kinase kinases. MAPKs, including JNKs, can be
deactivated by a specialized group of phosphatases, called MAP kinase
phosphatases. JNK phosphorylates and regulates the activity of transcription
factors other than c-Jun, including ATF2, Elk-1, p53 and c-Myc and
non-transcription factors, such as members of the Bcl-2 family. The pathway
plays a critical role in cell proliferation, apoptosis, angiogenesis and
migration. In this review, an overview of the functions that are related to
rheumatic diseases is presented. In addition, some diseases in which JNK
participates will be highlighted. The c-Jun N-terminal kinase (JNK) pathway forms part of the mitogen-activated
protein kinase (MAPK) signaling pathways comprising a sequential three-tiered
kinase cascade. Here, an upstream MAP3K (MEKK1) phosphorylates and activates a
MAP2K (MKK4 and MKK7), which in turn phosphorylates and activates the MAPK, JNK.
The C-terminal kinase domain of MEKK1 (MEKK-C) is constitutively active, while
MKK4/7 and JNK are both activated by dual phosphorylation of S/Y, and T/Y
residues within their activation loops, respectively. While improvements in the
purification of large quantities of active JNKs have recently been made,
inadequacies in their yield, purity, and the efficiency of their phosphorylation
still exist. We describe a novel and robust method that further improves upon
the purification of large yields of highly pure, phosphorylated JNK1β1, which is
most suitable for biochemical and biophysical characterization. Codon
harmonization of the JNK1β1 gene was used as a precautionary measure toward
increasing the soluble overexpression of the kinase. While JNK1β1 and its
substrate ATF2 were both purified to >99% purity as GST fusion proteins using
GSH-agarose affinity chromatography and each cleaved from GST using thrombin,
constitutively-active MEKK-C and inactive MKK4 were separately expressed in E.
coli as thioredoxin-His(6)-tagged proteins and purified using urea refolding and
Ni(2+)-IMAC, respectively. Activation of JNK1β1 was then achieved by
successfully reconstituting the JNK MAPK activation cascade in vitro; MEKK-C was
used to activate MKK4, which in turn was used to efficiently phosphorylate and
activate large quantities of JNK1β1. Activated JNK1β1 was thereafter able to
phosphorylate ATF2 with high catalytic efficiency. Tylophorine, a phethroindolizidine alkaloid, is the major medicinal
constituent of herb Tylophora indica. Tylophorine treatment increased the
accumulation of c-Jun protein, a component of activator protein 1 (AP1), in
carcinoma cells. An in vitro kinase assay revealed that the resultant c-Jun
phosphorylation was primarily mediated via activated c-Jun N-terminal protein
kinase (JNK). Moreover, flow cytometry indicated that ectopically overexpressed
c-Jun in conjunction with tylophorine significantly increased the number of
carcinoma cells that were arrested at the G1 phase. The tylophorine-mediated
downregulation of cyclin A2 protein levels is known to be involved in the
primary G1 arrest. Chromatin immunoprecipitation and reporter assays revealed
that tylophorine enhanced the c-Jun downregulation of the cyclin A2 promoter
activity upon increased binding of c-Jun to the deregulation AP1 site and
decreased binding to the upregulation activating transcription factor (ATF) site
in the cyclin A2 promoter, thereby reducing cyclin A2 expression. Further,
biochemical studies using pharmacological inhibitors and RNA silencing
approaches demonstrated that tylophorine-mediated elevation of the c-Jun protein
level occurs primarily via two discrete prolonged signaling pathways: (i) the
NF-κB/PKCδ_(MKK4)_JNK cascade, which phosphorylates c-Jun and increases its
stability by slowing its ubiquitination, and (ii) the PI3K_PDK1_PP2A_eEF2
cascade, which sustains eukaryotic elongation factor 2 (eEF2) activity and thus
c-Jun protein translation. To the best of our knowledge, this report is the
first to demonstrate the involvement of c-Jun in the anticancer activity of
tylophorine and the release of c-Jun translation from a global translational
blockade via the PI3K_PDK1_eEF2 signaling cascade. Cellular inflammatory response plays an important role in ischemic brain injury
and anti-inflammatory treatments in stroke are beneficial. Dietary
supplementation with docosahexaenoic acid (DHA) shows anti-inflammatory and
neuroprotective effects against ischemic stroke. However, its effectiveness and
its precise modes of neuroprotective action remain incompletely understood. This
study provides evidence of an alternative target for DHA and sheds light on the
mechanism of its physiological benefits. We report a global inhibitory effect of
3 consecutive days of DHA preadministration on circulating and intracerebral
cellular inflammatory responses in a rat model of permanent cerebral ischemia.
DHA exhibited a neuroprotective effect against ischemic deficits by reduction of
behavioral disturbance, brain infarction, edema and blood-brain barrier
disruption. The results of enzymatic assay, Western blot, real-time reverse
transcriptase polymerase chain reaction and flow cytometric analysis revealed
that DHA reduced central macrophages/microglia activation, leukocyte
infiltration and pro-inflammatory cytokine expression and peripheral leukocyte
activation after cerebral ischemia. In parallel with these immunosuppressive
phenomena, DHA attenuated post-stroke oxidative stress, c-Jun N-terminal kinase
(JNK) phosphorylation, c-Jun phosphorylation and activating protein-1 (AP-1)
activation but further elevated ischemia-induced NF-E2-related factor-2 (Nrf2)
and heme oxygenase-1 (HO-1) expression. DHA treatment also had an
immunosuppressive effect in lipopolysaccharide/interferon-γ-stimulated glial
cultures by attenuating JNK phosphorylation, c-Jun phosphorylation and AP-1
activation and augmenting Nrf2 and HO-1 expression. In summary, we have shown
that DHA exhibited neuroprotective and anti-inflammatory effects against
ischemic brain injury and these effects were accompanied by decreased oxidative
stress and JNK/AP-1 signaling as well as enhanced Nrf2/HO-1 expression. Many clinical cases have been reported where epilepsy profoundly influenced the
pathophysiological function of the heart; however, the underlying mechanisms
were not elucidated. We use the tremor (TRM) rat as an animal model of epilepsy
to investigate the potential mechanisms of myocardial injury. Cardiac functions
were assessed by arrhythmia score, heart rate, heart:body mass ratio, and
hemodynamic parameters including left ventricular systolic pressure (LVSP), left
ventricular end-diastolic pressure (LVEDP), and maximum rate of left ventricular
pressure rise and fall (+dp/dtmax and -dp/dtmax). Catecholamine level was
detected by HPLC. Apoptotic index was estimated by TUNEL assay. The expressions
of Bcl-2, Bax, caspase-3, extracellular signal-regulated protein kinase (ERK),
c-Jun NH2-terminal protein kinases (JNK), and p38 were evaluated by Western
blot. The results indicated that there existed cardiac dysfunction and
cardiomyocyte apoptosis, accompanied by increasing catecholamine levels in TRM
rats. Further investigation revealed that apoptosis was mediated by reducing
Bcl-2, upregulating Bax, and activating caspase-3. Additional experiments
demonstrated that P-ERK1/2 was decreased, whereas P-JNK and P-p38 were
up-regulated. Our results suggest that the sympathetic nervous system activation
and cardiomyocyte apoptosis are involved in the myocardial injury of TRM rats.
The mechanisms of apoptosis might be associated with the activation of the
mitochondria-initiated and the mitogen-activated protein kinase pathways. BACKGROUND: The c-Jun N-terminal kinase (JNK) is thought to be involved in
inflammation, proliferation and apoptosis.
AIM: To examine the role of JNK isoforms in metastasis, proliferation, migration
and invasion of the maligt melanoma (MM) cell lines SK-MEL-28, SK-MEL-3 and
WM164, using a kinase-specific inhibitor or isoform-specific small interfering
(si)RNAs.
RESULTS: SK-MEL-3, a cell line established from metastatic MM, showed slightly
increased phosphorylation of both JNK1 and JNK2, whereas WM164, a cell line
derived from primary MM, showed significant phosphorylation of JNK1. A JNK
inhibitor, SP600125, inhibited cell proliferation of SK-MEL-3 but not SK-MEL-28
or WM164. Transfection of JNK1-specific siRNA reduced the migratory activity of
WM164 cells, while silencing of either JNK1 or JNK2 strongly suppressed the
invasive activity of SK-MEL-3.
CONCLUSIONS: Our study suggests that JNK isoforms have different roles in MM.
Metastasis of MM may be regulated by JNK2, while invasion is regulated by both
JNK1 and JNK2. JNK1 and JNK2 respectively mediate cell migration and cell
proliferation. Further understanding of the specific roles of JNK isoforms in
the pathogenesis of MM may lead to the development of therapies targeting
specific isoforms. Alzheimer's disease (AD) is characterized by accumulation of two misfolded and
aggregated proteins, β-amyloid and hyperphosphorylated tau. Both cellular
systems responsible for clearance of misfolded and aggregated proteins, the
lysosomal and the proteasomal, have been shown to be malfunctioning in the aged
brain and more so in patients with neurodegenerative diseases, including AD.
This malfunction could be contributing to β-amyloid and tau accumulation,
eventually aggregating in plaques and tangles. We have investigated the impact
of decreased proteasome activity on tau phosphorylation as well as on
microtubule stability and transport. To do this, we used our recently developed
neuronal model where human SH-SY5Y cells obtain neuronal morphology and function
through differentiation. We found that exposure to low doses of the proteasome
inhibitor MG-115 caused tau phosphorylation, microtubule destabilization and
disturbed neuritic transport. Furthermore, reduced proteasome activity activated
several proteins implicated in tau phosphorylation and AD pathology, including
c-Jun N-terminal kinase, c-Jun and extracellular signal-regulated protein kinase
(ERK) 1/2. Restoration of the microtubule transport was achieved by inhibiting
ERK 1/2 activation, and simultaneous inhibition of both ERK 1/2 and c-Jun
reversed the proteasome inhibition-induced tau phosphorylation. Taken together,
this study suggests that a decrease in proteasome activity can, through
activation of c-Jun and ERK 1/2, result in several events related to
neurodegenerative diseases. Restoration of proteasome activity or modulation of
ERK 1/2 and c-Jun function can open new treatment possibilities against
neurodegenerative diseases such as AD. Bone degradation is a serious complication of chronic inflammatory diseases such
as septic arthritis, osteomyelitis, and infected orthopedic implant failure. Up
to date, effective therapeutic treatments for bacteria-caused bone destruction
are limited. In our previous study, we found that LPS promoted osteoclast
differentiation and activity through activation of mitogen-activated protein
kinases (MAPKs) pathway such as c-Jun N-terminal kinases (JNK) and extracellular
signal regulated kinase (ERK1/2). The current study was to evaluate the
mechanism of LPS on the apoptosis and osteoblast differentiation in MC3T3-E1
cells. MC3T3-E1 osteoblasts were non-treated, treated with LPS. After treatment,
the cell viability, the activity of alkaline phosphatase (ALP) and caspase-3
were measured. The expressions of osteoblast-specific genes and Bax, Bcl-2, and
caspase-3 were determined by real-time quantitative polymerase chain reaction
(qPCR). Protein levels of Bax, Bcl-2, caspase-3, and phosphorylation of MAPKs
were measured using Western blotting assays. The MAPK signaling pathway was
blocked by pretreatment with JNK inhibitor SP600125. LPS treatment induced a
significant decrease in cell metabolism, viability, and ALP activity in MC3T3-E1
cells. LPS also significantly decreased mRNA expressions of osteoblast-related
genes in MC3T3-E1 cells. On the other hand, LPS significantly upregulated mRNA
expressions and protein levels of Bax and caspase-3 as well as activation of
caspase-3, whereas decreased Bcl-2 expression in MC3T3-E1 cells. Furthermore,
LPS significantly promoted MAPK pathway including the phosphorylation of JNK and
the phosphorylation of ERK1/2; moreover, pretreatment with JNK inhibitor not
only attenuated both of phosphorylation-JNK and ERK1/2 enhanced by LPS in
MC3T3-E1 cells, but also reversed the downregulated expressions of
osteoblast-specific genes including ALP and BSP induced by LPS. In conclusion,
LPS could induce osteoblast apoptosis and inhibit osteoblast differentiation via
activation of JNK pathway. Sinodielide A (SA) is a naturally occurring guaianolide, which is isolated from
the root of Sinodielsia yunensis. This root, commonly found in Yun
province, is used in traditional Chinese medicine as an antipyretic, analgesic
and diaphoretic agent. A number of studies have reported that agents isolated
from a species of Umbelliferae (Apiaceae) have antitumor activities. We
previously reported, using combined treatments with this medicinal herb and
hyperthermia at various temperatures, an enhanced cytotoxicity in the human
prostate cancer androgen‑independent cell lines, PC3 and DU145, and analyzed the
related mechanisms. In the present study, we investigated the effects of
treatment with SA prior to hyperthermia on the thermosensitivity of DU145 cells,
and the mechanisms related to the induction of apoptosis and G(2)/M cell cycle
arrest via the activation of extracellular-regulated kinase (ERK)1/2, c-Jun
N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) signaling
pathways, as well as the phosphoinositide 3-kinase (PI3K)/Akt signaling
pathways. Cells were exposed to hyperthermia alone (40-44˚C) or hyperthermia in
combination with SA. Lethal damage to cells treated with mild hyperthermia (40
or 42˚C) for up to 6 h was slight; however, hyperthermia in combination with SA
synergistically enhanced thermosensivity. Lethal damage to cells treated with
acute hyperthermia (43 or 44˚C) was more severe, but these effects were also
enhanced and were more significant by the combined treatment with SA. The
kinetics of apoptosis induction and cell cycle distribution were analyzed by
flow cytometry. In addition, the levels of ERK1/2, JNK and Akt were determined
by western blot analysis. The incidence of apoptotic cells after treatment with
SA (20.0 µM) at 37˚C for 4 h, hyperthermia (44˚C) alone for 30 min, and the
combination in sequence were examined. The sub-G1 division (%) in the diagram
obtained by flow cytometry was applied to that assay. The percentage of
apoptotic cells (10.53±5.02%) was higher at 48 h as compared to 0, 12 and 24 h
after treatment. The distribution of DU145 cells in the G2/M cell cycle phase
was markedly increased after 24 h of heating at 44˚C and after the combined
treatment with heating and SA. The phosphorylation of ERK1/2 was reduced
following treatment with heating and SA, while the levels of phosphorylated JNK
(p-JNK) were markedly increased immediately after heating at 44˚C and when
heating was combined with SA. By contrast, the levels of phosphorylated Akt
(p-Akt) were immediately increased only after heating at 44˚C. Thus, we
concluded that SA exerts its thermosensitizing effects on DU145 cells by
inhibiting the activation of the MAPK/ERK1/2 and PI3K/Akt signaling pathways. We previously reported that jellyfish collagen stimulates both the acquired and
innate immune responses. In the acquired immune response, jellyfish collagen
enhanced immunoglobulin production by lymphocytes in vitro and in vivo.
Meanwhile, in the innate immune response jellyfish collagen promoted cytokine
production and phagocytotic activity of macrophages. The facts that jellyfish
collagen plays several potential roles in stimulating cytokine production by
macrophages have further attracted us to uncover its mechanisms. We herein
describe that the cytokine production-stimulating activity of jellyfish collagen
was canceled by a Toll-like receptor 4 (TLR4) inhibitor. Moreover, jellyfish
collagen stimulated phosphorylation of inhibitor of κBα (IκBα), promoted the
translocation of nucleus factor-κB (NF-κB), and activated c-Jun N-terminal
kinase (JNK). A JNK inhibitor also abrogated the cytokine production-stimulating
activity of jellyfish collagen. These results suggest that jellyfish collagen
may facilitate cytokine production by macrophages through activation of NF-κB
and JNK via the TLR4 signaling pathways. Previous reports suggested that protoapigenone showed remarkable antitumor
activities against a broad spectrum of human cancer cell lines, but had no
effect on human lung adenocarcinoma A549 cell. The lack of effective remedies
had necessitated the application of new therapeutic scheme. A novel compound
RY10-4 which has the similar structure close to protoapigenone showed better
antitumor activity. Treatment with RY10-4 inhibited the expression of
pro-caspase-3, pro-caspase-9, Bcl-2 as well as phosphorylation of signal
transducer and activator of transcription-3 (p-STAT3). It also reduced the
expressions of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9
(MMP-9) and increases the expressions of reversion-inducing cysteine-rich
protein with kazal motifs (RECK), as well as tissue inhibitor of
metalloproteinase (TIMP) via inhibiting STAT3 by activating the
mitogen-activated protein (MAP) kinases (the c-Jun N-terminal kinase (JNK), the
p38 and extracellular signal-regulated kinase (ERK)) in A549 cells treated with
RY10-4. Moreover, the cytotoxic effect of RY10-4 was induction of apoptosis in
A549 cells by enhancing production of reactive oxygen species (ROS). Taken
together, the observations suggested that RY10-4 had affected Bcl-2 family
members, caspases, MMPs, TIMPs expressions and ROS production via inhibiting
STAT3 activities through ERK and p38 pathways in A549 cells. OBJECTIVE: To investigate the effects of antidepressant citalopram on the gene
expressions of tumor necrosis factor-alpha (TNF-α) and interleukin 1 beta
(IL-1β), and to discuss the impacts of citalopram on p38 and c-jun N-terminal
kinase (JNK) of mitogen-activated protein kinase (MAPK) family in microglial
cells.
METHODS: BV2 cells were induced by lipopolysaccharide (LPS) to produce TNF-α and
IL-1β. After pretreatment with citalopram (20 μmol/L) for 4 h, the mRNA levels
of TNF-α and IL-1β were measured by quantitative real-time PCR (qRT-PCR); after
pretreatment for 24 h, the protein levels of TNF-α and IL-1β were analyzed by
ELISA; the effects of citalopram on the phosphorylation of p38MAPK and JNK were
observed after pretreatment for 30 min.
RESULTS: Citalopram significantly inhibited the mRNA and protein expressions of
TNF-α and IL-1β, and the phosphorylation of p38MAPK and JNK.
CONCLUSION: Citalopram may play the anti-inflammatory role by inhibiting MAPK
pathway in microglial cells. Steroid hormones exert genotropic effects through members of the nuclear hormone
receptor family. In the present study, we examined the effects of 17β-estradiol
(E2) on nitric oxide (NO) production following lipopolysaccharide (LPS)
stimulation and investigated the mechanisms in mouse bone marrow-derived
macrophages (BMMs). E2 alone did not affect NO production. In contrast, E2
inhibited LPS-induced production of NO in BMMs. Using a cell-impermeable E2
conjugated to BSA (E2-BSA), which has been used to investigate the nongenomic
effects of estrogen, we found that the increase in NO production induced by LPS
was also attenuated. In addition, the intracellular estrogen receptor blocker,
ICI 182780, only partially antagonized the total effects of E2 on LPS-stimulated
NO production capacity. E2 also attenuated the LPS activation of p38
mitogen-activated protein kinase (MAPK) but not that of extracellular-regulated
protein kinase 1/2 (ERK1/2) and c-Jun NH2-terminal kinase (JNK). This
attenuation was not abrogated by ICI 182780. Moreover, the p38 inhibitor, SB
203580, greatly reduced the LPS-induced NO production, and the remaining NO
levels were no longer regulated by E2. Additionally, E2-BSA inhibited
LPS-mediated changes in p38 MAPK activation to the same extent as E2. Moreover,
E2 and E2-BSA inhibited LPS-induced activation of nuclear factor-kappa B (NF-κB)
and activator protein 1 (AP-1). This inhibitory effect of E2 was only partially
antagonized by ICI 182780. Taken together, these results suggest that E2 has an
inhibitory effect on LPS-induced NO production in BMMs through inhibition of p38
MAPK phosphorylation, and blockade of NF-κB and AP-1 activation. These effects
are mediated at least in part via a nongenomic pathway. |
What is the meaning of the acronym "TAILS" used in protein N-terminomics? | TAILS stands for "Terminal Amine Isotopic Labeling of Substrates" | The neutrophil-specific protease membrane-type 6 matrix metalloproteinase
(MT6-MMP)/MMP-25/leukolysin is implicated in multiple sclerosis and cancer yet
remains poorly characterized. To characterize the biological roles of MT6-MMP,
it is critical to identify its substrates for which only seven are currently
known. Here, we biochemically characterized MT6-MMP, profiled its tissue
inhibitor of metalloproteinase inhibitory spectrum, performed degradomics
analyses, and screened 26 chemokines for cleavage using matrix-assisted laser
desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. MT6-MMP
processes seven each of the CXC and CC chemokine subfamilies. Notably, cleavage
of the neutrophil chemoattractant CXCL5 activates the chemokine, thereby
increasing its agonist activity, indicating a feed-forward mechanism for
neutrophil recruitment. Likewise, cleavage also activated CCL15 and CCL23 to
increase monocyte recruitment. Utilizing the proteomics approach proteomic
identification of cleavage site specificity (PICS), we identified 286 peptidic
cleavage sites spanning from P6 to P6' from which an unusual glutamate
preference in P1 was identified. The degradomics screen terminal amine isotopic
labeling of substrates (TAILS), which enriches for neo-N-terminal peptides of
cleaved substrates, was used to identify 58 new native substrates in fibroblast
secretomes after incubation with MT6-MMP. Vimentin, cystatin C, galectin-1,
IGFBP-7, and secreted protein, acidic and rich in cysteine (SPARC) were among
those substrates we biochemically confirmed. An extracellular "moonlighting"
form of vimentin is a chemoattractant for THP-1 cells, but MT6-MMP cleavage
abolished monocyte recruitment. Unexpectedly, the MT6-MMP-cleaved vimentin
potently stimulated phagocytosis, which was not a property of the full-length
protein. Hence, MT6-MMP regulates neutrophil and monocyte chemotaxis and by
generating "eat-me" signals upon vimentin cleavage potentially increases
phagocytic removal of neutrophils to resolve inflammation. Proteolysis represents one of the most tightly controlled physiological
processes, as proteases create events that will typically commit pathways in an
irreversible manner. Despite their implication in nearly all biological systems,
our understanding of the role of proteases in disease pathology is often
limited. Several approaches to studying proteolytic activity as it relates to
biology, pathophysiology, and drug therapy have been published, including the
recently described terminal amine isotopic labeling of substrates (TAILS)
strategy by Kleifeld and colleagues. Here, we investigate TAILS as a methodology
based on targeted enrichment and mass spectrometric detection of endogenous
N-terminal peptides from clinically relevant biological samples and its
potential to provide quantitative information on proteolysis and elucidation of
the protease cleavage sites. While optimizing the most current protocol, by
switching to a streamlined one-tube format and simplifying the reagents' removal
steps, we demonstrate the advantages over previously published methods and
provide solutions to some of the technical challenges presented in the Kleifeld
publication. We also identify some of the current and unresolved limitations. We
use human plasma as a model system to provide data, which illustrates some of
the key analytical parameters of the modified TAILS procedure, including
specificity, sensitivity, quantitative precision, and accuracy. Data analysis in proteomics is complex and with the extra challenges involved in
the interpretation of data from N-terminomics experiments, this can be
daunting.Therefore, we have devised a rational pipeline of steps to approach
N-terminomics data analysis in a statistically based and valid manner. We have
automated these steps in CLIPPER, an add-on to the Trans-Proteomic
Pipeline(TPP). Applying CLIPPER to the analysis of N- terminomics data generated
by terminal amine isotopic labeling of substrates (TAILS) enables high
confidence peptide to protein assignment, protein N-terminal characterization
and annotation, and for protease analysis readily allows protease substrate
discovery with high confidence. |
Do mutations of AKT1 occur in meningiomas? | Yes, AKT1 mutation occurs in meningiomas. | Meningiomas are the most common primary nervous system tumor. The tumor
suppressor NF2 is disrupted in approximately half of all meningiomas, but the
complete spectrum of genetic changes remains undefined. We performed
whole-genome or whole-exome sequencing on 17 meningiomas and focused sequencing
on an additional 48 tumors to identify and validate somatic genetic alterations.
Most meningiomas had simple genomes, with fewer mutations, rearrangements and
copy-number alterations than reported in other tumors in adults. However,
several meningiomas harbored more complex patterns of copy-number changes and
rearrangements, including one tumor with chromothripsis. We confirmed focal NF2
inactivation in 43% of tumors and found alterations in epigenetic modifiers in
an additional 8% of tumors. A subset of meningiomas lacking NF2 alterations
harbored recurrent oncogenic mutations in AKT1 (p.Glu17Lys) and SMO
(p.Trp535Leu) and exhibited immunohistochemical evidence of activation of these
pathways. These mutations were present in therapeutically challenging tumors of
the skull base and higher grade. These results begin to define the spectrum of
genetic alterations in meningiomas and identify potential therapeutic targets. We report genomic analysis of 300 meningiomas, the most common primary brain
tumors, leading to the discovery of mutations in TRAF7, a proapoptotic E3
ubiquitin ligase, in nearly one-fourth of all meningiomas. Mutations in TRAF7
commonly occurred with a recurrent mutation (K409Q) in KLF4, a transcription
factor known for its role in inducing pluripotency, or with AKT1(E17K), a
mutation known to activate the PI3K pathway. SMO mutations, which activate
Hedgehog signaling, were identified in ~5% of non-NF2 mutant meningiomas. These
non-NF2 meningiomas were clinically distinctive-nearly always benign, with
chromosomal stability, and originating from the medial skull base. In contrast,
meningiomas with mutant NF2 and/or chromosome 22 loss were more likely to be
atypical, showing genomic instability, and localizing to the cerebral and
cerebellar hemispheres. Collectively, these findings identify distinct
meningioma subtypes, suggesting avenues for targeted therapeutics. 1. Cancer Discov. 2013 Mar;3(3):OF13. doi: 10.1158/2159-8290.CD-RW2013-028. Epub
2013 Feb 7. Meningiomas arise from the arachnoid layer of the meninges that surround the
brain and spine. They account for over one third of all primary central nervous
system tumors in adults and confer a significant risk of location-dependent
morbidity due to compression or displacement. A significant increase in risk of
meningiomas is associated with neurofibromatosis type 2 (NF2) disease through
mutation of the NF2 gene. In addition, approximately 5% of individuals with
schwannomatosis disease develop meningiomas, through mutation of the SWI/SNF
chromatin remodeling complex subunit, SMARCB1. Recently, a second SWI/SNF
complex subunit, SMARCE1, was identified as a cause of clear cell meningiomas,
indicating a wider role for this complex in meningioma disease. The sonic
hedgehog (SHH)-GLI1 signaling pathway gene, SUFU, has also been identified as
the cause of hereditary multiple meningiomas in a large Finnish family. The
recent identification of somatic mutations in components of the SHH-GLI1 and
AKT1-MTOR signaling pathways indicates the potential for cross talk of these
pathways in the development of meningiomas. This review describes the known
meningioma predisposition genes and their links to the recently identified
somatic mutations. |
What are the main indications of lacosamide? | Lacosamide is an anti-epileptic drug, licensed for refractory partial-onset seizures. In addition to this, it has demonstrated analgesic activity in various animal models. Apart from this, LCM has demonstrated potent effects in animal models for a variety of CNS disorders like schizophrenia and stress induced anxiety. | This paper comprises a series of experiments in rodent models of partial and
generalized epilepsy which were designed to describe the anti-convulsant profile
of the functionalized amino acid lacosamide. Lacosamide was effective against
sound-induced seizures in the genetically susceptible Frings mouse, against
maximal electroshock test (MES)-induced seizures in rats and mice, in the rat
hippocampal kindling model of partial seizures, and in the 6Hz model of
psychomotor seizures in mice. The activity in the MES test in both mice
(4.5mg/kg i.p.) and rats (3.9 mg/kg p.o.) fell within the ranges previously
reported for most clinically available anti-epileptic drugs. At both the median
effective dose for MES protection, as well as the median toxic dose for rotorod
impairment, lacosamide elevated the seizure threshold in the i.v.
pentylenetetrazol seizure test, suggesting that it is unlikely to be
pro-convulsant at high doses. Lacosamide was inactive against clonic seizures
induced by subcutaneous administration of the chemoconvulsants
pentylenetetrazol, bicuculline, and picrotoxin, but it did inhibit NMDA-induced
seizures in mice and showed full efficacy in the homocysteine model of epilepsy.
In summary, the overall anti-convulsant profile of lacosamide appeared to be
unique, and the drug displayed a good margin of safety in those tests in which
it was effective. These results suggest that lacosamide may have the potential
to be clinically useful for at least the treatment of generalized tonic-clonic
and partial-onset epilepsies, and support ongoing clinical trials in these
indications. Lacosamide (LCM), (SPM 927, (R)-2-acetamido-N-benzyl-3-methoxypropionamide,
previously referred to as harkoseride or ADD 234037) is a member of a series of
functionalized amino acids that were specifically synthesized as anticonvulsive
drug candidates. LCM has demonstrated antiepileptic effectiveness in different
rodent seizure models and antinociceptive potential in experimental animal
models that reflect distinct types and symptoms of neuropathic as well as
chronic inflammatory pain. Recent results suggest that LCM has a dual mode of
action underlying its anticonvulsant and analgesic activity. It was found that
LCM selectively enhances slow inactivation of voltage-gated sodium channels
without affecting fast inactivation. Furthermore, employing proteomic
affinity-labeling techniques, collapsin-response mediator protein 2 (CRMP-2
alias DRP-2) was identified as a binding partner. Follow-up experiments
confirmed a functional interaction of LCM with CRMP-2 in vitro. LCM did not
inhibit or induce a wide variety of cytochrome P450 enzymes at therapeutic
concentrations. In safety pharmacology and toxicology studies conducted in mice,
rats, rabbits, and dogs, LCM was well tolerated. Either none or only minor side
effects were observed in safety studies involving the central nervous,
respiratory, gastrointestinal, and renal systems and there is no indication of
abuse liability. Repeated dose toxicity studies demonstrated that after either
intravenous or oral administration of LCM the adverse events were reversible and
consisted mostly of exaggerated pharmacodynamic effects on the CNS. No genotoxic
or carcinogenic effects were observed in vivo, and LCM showed a favorable
profile in reproductive and developmental animal studies. Currently, LCM is in a
late stage of clinical development as an adjunctive treatment for patients with
uncontrolled partial-onset seizures, and it is being assessed as monotherapy in
patients with painful diabetic neuropathy. Further trials to identify LCM's
potential in pain and for other indications have been initiated. Collapsin response mediator protein-2 (DPYSL2 or CRMP2) is a multifunctional
adaptor protein within the central nervous system. In the developing brain or
cell cultures, CRMP2 performs structural and regulatory functions related to
cytoskeletal dynamics, vesicle trafficking and synaptic physiology whereas CRMP2
functions in adult brain are still being elucidated. CRMP2 has been associated
with several neuropathologic or psychiatric conditions including Alzheimer's
disease (AD) and schizophrenia, either at the level of genetic polymorphisms;
protein expression; post-translational modifications; or protein/protein
interactions. In AD, CRMP2 is phosphorylated by glycogen synthase kinase-3β
(GSK3β) and cyclin dependent protein kinase-5 (CDK5), the same kinases that act
on tau protein in generating neurofibrillary tangles (NFTs). Phosphorylated
CRMP2 collects in NFTs in association with the synaptic structure-regulating
SRA1/WAVE1 (specifically Rac1-associated protein-1/WASP family
verprolin-homologous protein-1) complex. This phenomenon could plausibly
contribute to deficits in neural and synaptic structure that have been well
documented in AD. This review discusses the essential biology of CRMP2 in the
context of nascent data implicating CRMP2 perturbations as either a correlate
of, or plausible contributor to, diverse neuropathologies. A discussion is made
of recent findings that the atypical antidepressant tianeptine increases CRMP2
expression, whereas other, neuroactive small molecules including the epilepsy
drug lacosamide and the natural brain metabolite lanthionine ketimine appear to
bind CRMP2 directly with concomitant affects on neural structure. These findings
constitute proofs-of-concept that pharmacological manipulation of CRMP2 is
possible and hence, may offer new opportunities for therapy development against
certain neurological diseases. PURPOSE OF REVIEW: There is a need for newer anti-epileptic drugs (AEDs) with
improved efficacy and tolerability. This article reviews AEDs introduced since
2007 and investigational compounds in clinical development.
RECENT FINDINGS: Two recently introduced AEDs, stiripentol and rufinamide, have
been licensed exclusively for orphan indications, that is severe myoclonic
epilepsy of infancy (stiripentol, Europe) and Lennox-Gastaut syndrome
(rufinamide, Europe and the USA). This signals a welcome new trend to explore
novel treatments in specific pediatric syndromes for which there are high
therapeutic needs. Two additional AEDs, lacosamide and eslicarbazepine acetate,
have been licensed recently for a more traditional indication, refractory
partial-onset seizures. Although newly introduced agents given as adjunctive
therapy have been found to be superior to placebo in reducing seizure frequency,
the ultimate goal of sustained seizure freedom is rarely achieved. Therefore,
the search for better agents should continue. Several investigational compounds
are currently in various stages of clinical development.
SUMMARY: The recent introduction of newer AEDs has enlarged the armamentarium
against epilepsy. However, newer agents had only a modest impact on the
probability of achieving long-term remission. Novel strategies for the discovery
and development of truly innovative AEDs are sorely needed. Blood (serum/plasma) antiepileptic drug (AED) therapeutic drug monitoring (TDM)
has proven to be an invaluable surrogate marker for individualizing and
optimizing the drug management of patients with epilepsy. Since 1989, there has
been an exponential increase in AEDs with 23 currently licensed for clinical
use, and recently, there has been renewed and extensive interest in the use of
saliva as an alternative matrix for AED TDM. The advantages of saliva include
the fact that for many AEDs it reflects the free (pharmacologically active)
concentration in serum; it is readily sampled, can be sampled repetitively, and
sampling is noninvasive; does not require the expertise of a phlebotomist; and
is preferred by many patients, particularly children and the elderly. For each
AED, this review summarizes the key pharmacokinetic characteristics relevant to
the practice of TDM, discusses the use of other biological matrices with
particular emphasis on saliva and the evidence that saliva concentration
reflects those in serum. Also discussed are the indications for salivary AED
TDM, the key factors to consider when saliva sampling is to be undertaken, and
finally, a practical protocol is described so as to enable AED TDM to be applied
optimally and effectively in the clinical setting. Overall, there is compelling
evidence that salivary TDM can be usefully applied so as to optimize the
treatment of epilepsy with carbamazepine, clobazam, ethosuximide, gabapentin,
lacosamide, lamotrigine, levetiracetam, oxcarbazepine, phenobarbital, phenytoin,
primidone, topiramate, and zonisamide. Salivary TDM of valproic acid is probably
not helpful, whereas for clonazepam, eslicarbazepine acetate, felbamate,
pregabalin, retigabine, rufinamide, stiripentol, tiagabine, and vigabatrin, the
data are sparse or nonexistent. Network analysis is an emerging tool for the study of complex systems.
Antiepileptic drug (AED) polytherapy in children with medically intractable
epilepsy may be considered a complex system, given the heterogeneity of drug
combinations that are frequently modified according to clinical indications. The
current article presents a concise review of network theory and its application
to the characterization of AED use in children with refractory epilepsy. Current
and previous AEDs prescribed to 27 children with refractory,
localization-related epilepsy were recorded, and network theory was applied to
identify patterns of drug administration. Of the fifteen unique AEDs prescribed,
levetiracetam possessed the highest betweenness centrality within the network.
Furthermore, first generation AEDs were often discontinued, while lacosamide and
topiramate were most likely to be initiated. We also identified three
subnetworks of AEDs that were commonly coadministered. We conclude that network
analysis is an effective method to characterize the complexity of AED
administration patterns in children with epilepsy with many promising future
applications. |
Which fusion protein is involved in the development of Ewing sarcoma? | Ewing sarcoma is the second most common bone malignancy in children and young adults. In almost 95% of the cases, it is driven by oncogenic fusion protein EWS/FLI1, which acts as an aberrant transcription factor, that upregulates or downregulates target genes, leading to cellular transformation. | The Ewing family of tumors harbors chromosomal translocations that join the
N-terminal region of the EWS gene with the C-terminal region of several
transcription factors of the ETS family, mainly FLI1, resulting in chimeric
transcription factors that play a pivotal role in the pathogenesis of Ewing
tumors. To identify downstream targets of the EWS/FLI1 fusion protein, we
established 293 cells expressing constitutively either the chimeric EWS/FLI1 or
wild type FLI1 proteins and used cDNA arrays to identify genes differentially
regulated by EWS/FLI1. DAX1 (NR0B1), an unusual orphan nuclear receptor involved
in gonadal development, sex determination and steroidogenesis, showed a
consistent up-regulation by EWS/FLI1 oncoprotein, but not by wild type FLI1.
Specific induction of DAX1 by EWS/FLI1 was confirmed in two independent cell
systems with inducible expression of EWS/FLI1. We also analyzed the expression
of DAX1 in Ewing tumors and derived cell lines, as well as in other nonrelated
small round cell tumors. DAX1 was expressed in all Ewing tumor specimens
analyzed, and in seven out of eight Ewing tumor cell lines, but not in any
neuroblastoma or embryonal rhabdomyosarcoma. Furthermore, silencing of EWS/FLI1
by RNA interference in a Ewing tumor cell line markedly reduced the levels of
DAX1 mRNA and protein, confirming that DAX1 up-regulation is dependent upon
EWS/FLI1 expression. The high levels of DAX1 found in Ewing tumors and its
potent transcriptional repressor activity suggest that the oncogenic effect of
EWS/FLI1 may be mediated, at least in part, by the up-regulation of DAX1
expression. Our understanding of Ewing's sarcoma development mediated by the EWS/FLI fusion
protein has been limited by a lack of knowledge regarding the tumor cell of
origin. To circumvent this, we analyzed the function of EWS/FLI in Ewing's
sarcoma itself. By combining retroviral-mediated RNA interference with
reexpression studies, we show that ongoing EWS/FLI expression is required for
the tumorigenic phenotype of Ewing's sarcoma. We used this system to define the
full complement of EWS/FLI-regulated genes in Ewing's sarcoma. Functional
analysis revealed that NKX2.2 is an EWS/FLI-regulated gene that is necessary for
oncogenic transformation in this tumor. Thus, we developed a highly validated
transcriptional profile for the EWS/FLI fusion protein and identified a critical
target gene in Ewing's sarcoma development. Sarcomas account for less than 10% of all human maligcies that are believed
to originate from as yet poorly defined mesenchymal progenitor cells. They
constitute some of the most aggressive adult and childhood cancers in that they
have a high metastatic proclivity and are typically refractory to conventional
chemo- and radiation therapy. Ewing's sarcoma is a member of Ewing's family
tumors (ESFT) and the second most common solid bone and soft tissue maligcy
of children and young adults. It is associated in 85% of cases with the
t(11;22)(q24:q12) chromosomal translocation that generates fusion of the 5'
segment of the EWS gene with the 3' segment of the ETS family gene FLI-1. The
resulting EWS-FLI-1 fusion protein is believed to behave as an aberrant
transcriptional activator that contributes to ESFT development by altering the
expression of its target genes in a permissive cellular environment. Although
ESFTs are among the best studied sarcomas, the mechanisms involved in
EWS-FLI-1-induced transformation require further elucidation and the primary
cells from which ESFTs originate need to be identified. This review will
highlight some of the most recent discoveries in the field of Ewing sarcoma
biology and origins. Ewing sarcoma/primitive neuroectodermal tumors (EWS/PNET) are characterized by
specific chromosomal translocations most often generating a chimeric EWS/FLI-1
gene. Depending on the number of juxtaposed exons assembled, several fusion
types have been described with different incidences and prognoses. To assess the
impact of each fusion type on the specific phenotypic, tumorigenic, and
metastatic features of EWS/PNET, we developed an amenable system using a murine
mesenchymal multipotent C3H10T1/2 cell line. Upon transduction of EWS/FLI-1,
cells acquired dramatic morphological changes in vitro, including a smaller size
and "neurite-like" membrane elongations. Chimeric fusion proteins conferred
oncogenic properties in vitro, including anchorage-independent growth and an
increased rate of proliferation. Furthermore, EWS/FLI-1 expression blocked
mineralization, with concomitant repression of osteoblastic genes, and induced a
dramatic repression of the adipocytic differentiation program. Moreover,
EWS/FLI-1 promoted an aberrant neural phenotype by the de novo expression of
specific neural genes. The intramuscular injection of transduced cells led to
tumor development and the induction of overt osteolytic lesions. Analogously, to
what was observed in human tumors, type 2 EWS/FLI-1 cells formed primary tumors
in immunodeficient mice with a higher incidence and a lower latency than cells
bearing types 1 and 3 fusions. By contrast, cells expressing types 2 and 3
fusions showed specific metastatic activity with a higher number of macroscopic
metastases in soft tissues and osteolytic lesions in the limbs as compared to
type-1-expressing cells. Therefore, the structure of each oncoprotein strongly
influenced its tumorigenicity and metastagenicity. Thus, this model provides a
basis for understanding the genetic determits involved in Ewing tumor
development and metastatic activity and represents a cellular system to analyze
other oncoproteins involved in human sarcomagenesis. Ewing's sarcomas are characterized by recurrent chromosomal translocations
expressing EWS-ETS fusion proteins, the most common of which is EWS-FLI.(1-5)
EWS-FLI is an oncogenic transcription factor that regulates genes involved in
tumorigenesis.(6,7) Because the Ewing's sarcoma cell of origin remains unknown,
a variety of model systems have been developed to study EWS-FLI fusions,(8-14)
and multiple microarray experiments describing potential EWS-FLI target genes
have been reported.(8,10,11,13,15-21) Each model has potential benefits and
drawbacks, but a large-scale comparison of these has not been reported. Herein
we report a meta-analysis of the genes that are dysregulated by EWS-FLI in
Ewing's sarcoma model systems. In general, EWS-FLI gain- and loss-of-function
models in human cell types were well correlated to patient-derived tumor
samples, while murine models were not. Using frequency analysis of dysregulated
genes across multiple model systems, we identified a conserved "core" EWS-FLI
transcriptional signature. This signature contained many of the genes known to
be involved in the tumorigenic phenotype of Ewing's sarcoma, and also contained
genes that have not been previously reported. Comparisons between the core
EWS-FLI signature and published mesenchymal stem cell data support the recent
assertion that mesenchymal stem cells are likely the Ewing's sarcoma precursor
cell.(15) These results demonstrate the utility of using comparative analysis to
validate model systems and emphasize the unique potential of this approach to
identify both oncogenic and background cell signatures. Ewing's tumour is the second most frequent primary tumour of bone. It is
associated in 85% of cases with a specific and recurrent chromosome
translocation, a t(11; 22)(q24; q12) which generates a fusion gene between the
5' part of EWS and the 3' part of FLI-1, a member of the ETS family. Less
frequently, this gene fusion involves EWS and another member of the ETS family
which can be: ERG, ETV1, E1AF or FEV depending on the cases. The EWS-ETS fusion
is causative in the development of Ewing's tumour. Its mechanism of action
mainly relies on the abnormal transcription regulation of key target genes which
are involved in the regulation of cell cycle, signal transduction, migration.
The cellular context within which EWS-FLI-1 exerts its oncogenic action is a
long standing matter of debate. Recent data converge to suggest that the Ewing
cell origin is a mesenchymal stem cell. Ewing's sarcoma is a maligt bone-associated tumor of children and young
adults. Most cases of Ewing's sarcoma express the EWS/FLI fusion protein.
EWS/FLI functions as an aberrant ETS-type transcription factor and serves as the
master regulator of Ewing's sarcoma-transformed phenotype. We recently showed
that EWS/FLI regulates one of its key targets, NR0B1, through a
GGAA-microsatellite in its promoter. Whether other critical EWS/FLI targets are
also regulated by GGAA-microsatellites was unknown. In this study, we combined
transcriptional analysis, whole genome localization data, and RNA interference
knockdown to identify glutathione S-transferase M4 (GSTM4) as a critical EWS/FLI
target gene in Ewing's sarcoma. We found that EWS/FLI directly binds the GSTM4
promoter, and regulates GSTM4 expression through a GGAA-microsatellite in its
promoter. Reduction of GSTM4 levels caused a loss of oncogenic transformation.
Furthermore, reduction of GSTM4 resulted in an increased sensitivity of Ewing's
sarcoma cells to chemotherapeutic agents, suggesting a role for this protein in
drug resistance. Consistent with this hypothesis, patients with Ewing's sarcoma
whose tumors had higher levels of GSTM4 expression had worse outcomes than those
with lower expression levels. These data show that GSTM4 contributes to the
cancerous behavior of Ewing's sarcoma and define a wider role for
GGAA-microsatellites in EWS/FLI function than previously appreciated. These data
also suggest a novel therapeutic resistance mechanism, in which the central
oncogenic abnormality directly regulates a resistance gene. Ewing sarcoma family of tumors (ESFT) is a group of aggressive pediatric
maligcies driven by the EWS-FLI1 fusion protein, an aberrant transcription
factor up-regulating specific target genes, such as neuropeptide Y (NPY) and its
Y1 and Y5 receptors (Y5Rs). Previously, we have shown that both exogenous NPY
and endogenous NPY stimulate ESFT cell death via its Y1 and Y5Rs. Here, we
demonstrate that this effect is prevented by dipeptidyl peptidases (DPPs), which
cleave NPY to its shorter form, NPY(3-36), not active at Y1Rs. We have shown
that NPY-induced cell death can be abolished by overexpression of DPPs and
enhanced by their down-regulation. Both NPY treatment and DPP blockade activated
the same cell death pathway mediated by poly(ADP-ribose) polymerase (PARP-1) and
apoptosis-inducing factor (AIF). Moreover, the decrease in cell survival induced
by DPP inhibition was blocked by Y1 and Y5R antagonists, confirming its
dependence on endogenous NPY. Interestingly, similar levels of NPY-driven cell
death were achieved by blocking membrane DPPIV and cytosolic DPP8 and DPP9.
Thus, this is the first evidence of these intracellular DPPs cleaving releasable
peptides, such as NPY, in live cells. In contrast, another membrane DPP,
fibroblast activation protein (FAP), did not affect NPY actions. In conclusion,
DPPs act as survival factors for ESFT cells and protect them from cell death
induced by endogenous NPY. This is the first demonstration that intracellular
DPPs are involved in regulation of ESFT growth and may become potential
therapeutic targets for these tumors. Ewing's sarcoma, a maligt bone tumor of children and young adults, is a
member of the small-round-blue-cell tumor family. Ewing's sarcoma family tumors
(ESFTs), which include peripheral primitive neuroectodermal tumors (PNETs), are
characterized by chromosomal translocations that generate fusions between the
EWS gene and ETS-family transcription factors, most commonly FLI1. The EWS-FLI1
fusion oncoprotein represents an attractive therapeutic target for treatment of
Ewing's sarcoma. The cell of origin of ESFT and the molecular mechanisms by
which EWS-FLI1 mediates tumorigenesis remain unknown, and few animal models of
Ewing's sarcoma exist. Here, we report the use of zebrafish as a vertebrate
model of EWS-FLI1 function and tumorigenesis. Mosaic expression of the human
EWS-FLI1 fusion protein in zebrafish caused the development of tumors with
histology strongly resembling that of human Ewing's sarcoma. The incidence of
tumors increased in a p53 mutant background, suggesting that the p53 pathway
suppresses EWS-FLI1-driven tumorigenesis. Gene expression profiling of the
zebrafish tumors defined a set of genes that might be regulated by EWS-FLI1,
including the zebrafish ortholog of a crucial EWS-FLI1 target gene in humans.
Stable zebrafish transgenic lines expressing EWS-FLI1 under the control of the
heat-shock promoter exhibit altered embryonic development and defective
convergence and extension, suggesting that EWS-FLI1 interacts with conserved
developmental pathways. These results indicate that functional targets of
EWS-FLI1 that mediate tumorigenesis are conserved from zebrafish to human and
provide a novel context in which to study the function of this fusion oncogene. Ewing sarcoma family tumors (ESFT) are highly aggressive and highly metastatic
tumors caused by a chromosomal fusion between the Ewing sarcoma protein (EWS)
with the transcription factor FLI-1. However, expression of the EWS/FLI-1
chimeric oncogene by itself is insufficient for carcinogenesis, suggesting that
additional events are required. Here, we report the identification of the Akt
substrate PRAS40 as an EWS target gene. EWS negatively regulates PRAS40
expression by binding the 3' untranslated region in PRAS40 mRNA. ESFT cell
proliferation was suppressed by treatment with an Akt inhibitor, and ESFT cell
proliferation and metastatic growth were suppressed by siRNA-mediated PRAS40
knockdown. Furthermore, PRAS40 knockdown was sufficient to reverse an increased
cell proliferation elicited by EWS knockdown. In support of a pathologic role
for PRAS40 elevation in EFST, we documented inverse protein levels of EWS and
PRAS40 in ESFT cells. Together, our findings suggest that PRAS40 promotes the
development of ESFT and might therefore represent a novel therapeutic target in
this aggressive disease. Ewing sarcoma is an aggressive pediatric cancer of the bone and soft tissue, in
which patients whose tumors have a poor histologic response to initial
chemotherapy have a poor overall prognosis. Therefore, it is important to
identify molecules involved in resistance to chemotherapy. Herein, we show that
the DNA repair protein and transcriptional cofactor, EYA3, is highly expressed
in Ewing sarcoma tumor samples and cell lines compared with mesenchymal stem
cells, the presumed cell-of-origin of Ewing sarcoma, and that it is regulated by
the EWS/FLI1 fusion protein transcription factor. We further show that EWS/FLI1
mediates upregulation of EYA3 via repression of miR-708, a miRNA that targets
the EYA3 3'-untranslated region, rather than by binding the EYA3 promoter
directly. Importantly, we show that high levels of EYA3 significantly correlate
with low levels of miR-708 in Ewing sarcoma samples, suggesting that this
miR-mediated mechanism of EYA3 regulation holds true in human cancers. Because
EYA proteins are important for cell survival during development, we examine, and
show, that loss of EYA3 decreases survival of Ewing sarcoma cells. Most
importantly, knockdown of EYA3 in Ewing sarcoma cells leads to sensitization to
DNA-damaging chemotherapeutics used in the treatment of Ewing sarcoma, and as
expected, after chemotherapeutic treatment, EYA3 knockdown cells repair DNA
damage less effectively than their control counterparts. These studies identify
EYA3 as a novel mediator of chemoresistance in Ewing sarcoma and define the
molecular mechanisms of both EYA3 overexpression and of EYA3-mediated
chemoresistance. Ewing sarcoma is the second most common bone maligcy in children and young
adults. It is driven by oncogenic fusion proteins (i.e. EWS/FLI1) acting as
aberrant transcription factors that upregulate and downregulate target genes,
leading to cellular transformation. Thus, identificating these target genes and
understanding their contribution to Ewing sarcoma tumorigenesis are key for the
development of new therapeutic strategies. In this study we show that lysyl
oxidase (LOX), an enzyme involved in maintaining structural integrity of the
extracellular matrix, is downregulated by the EWS/FLI1 oncoprotein and in
consequence it is not expressed in Ewing sarcoma cells and primary tumors. Using
a doxycycline inducible system to restore LOX expression in an Ewing sarcoma
derived cell line, we showed that LOX displays tumor suppressor activities.
Interestingly, we showed that the tumor suppressor activity resides in the
propeptide domain of LOX (LOX-PP), an N-terminal domain produced by proteolytic
cleavage during the physiological processing of LOX. Expression of LOX-PP
reduced cell proliferation, cell migration, anchorage-independent growth in soft
agar and formation of tumors in immunodeficient mice. By contrast, the
C-terminal domain of LOX, which contains the enzymatic activity, had the
opposite effects, corroborating that the tumor suppressor activity of LOX is
mediated exclusively by its propeptide domain. Finally, we showed that LOX-PP
inhibits ERK/MAPK signalling pathway, and that many pathways involved in cell
cycle progression were significantly deregulated by LOX-PP, providing a
mechanistic explanation to the cell proliferation inhibition observed upon
LOX-PP expression. In summary, our observations indicate that deregulation of
the LOX gene participates in Ewing sarcoma development and identify LOX-PP as a
new therapeutic target for one of the most aggressive paediatric maligcies.
These findings suggest that therapeutic strategies based on the administration
of LOX propeptide or functional analogues could be useful for the treatment of
this devastating paediatric cancer. Fusion of the EWS gene to FLI1 produces a fusion oncoprotein that drives an
aberrant gene expression program responsible for the development of Ewing
sarcoma. We used a homogenous proximity assay to screen for compounds that
disrupt the binding of EWS-FLI1 to its cognate DNA targets. A number of
DNA-binding chemotherapeutic agents were found to non-specifically disrupt
protein binding to DNA. In contrast, actinomycin D was found to preferentially
disrupt EWS-FLI1 binding by comparison to p53 binding to their respective
cognate DNA targets in vitro. In cell-based assays, low concentrations of
actinomycin D preferentially blocked EWS-FLI1 binding to chromatin, and
disrupted EWS-FLI1-mediated gene expression. Higher concentrations of
actinomycin D globally repressed transcription. These results demonstrate that
actinomycin D preferentially disrupts EWS-FLI1 binding to DNA at selected
concentrations. Although the window between this preferential effect and global
suppression is too narrow to exploit in a therapeutic manner, these results
suggest that base-preferences may be exploited to find DNA-binding compounds
that preferentially disrupt subclasses of transcription factors. EWS-FLI1 is an oncogenic fusion protein implicated in the development of Ewing's
sarcoma family tumors (ESFT). Using our previously reported lead compound 2
(YK-4-279), we designed and synthesized a focused library of analogues. The
functional inhibition of the analogues was measured by an EWS-FLI1/NR0B1
reporter luciferase assay and a paired cell screening approach measuring effects
on growth inhibition for human cells containing EWS-FLI1 (TC32 and TC71) and
control PANC1 cell lines devoid of the oncoprotein. Our data revealed that
substitution of electron donating groups at the para-position on the phenyl ring
was the most favorable for inhibition of EWS-FLI1 by analogs of 2. Compound 9u
(with a dimethylamino substitution) was the most active inhibitor with GI50 =
0.26 ± 0.1 μM. Further, a correlation of growth inhibition (EWS-FLI1 expressing
TC32 cells) and the luciferase reporter activity was established (R(2) = 0.84).
Finally, we designed and synthesized a biotinylated analogue and determined the
binding affinity for recombit EWS-FLI1 (Kd = 4.8 ± 2.6 μM). Ewing sarcoma is a maligt bone cancer that primarily occurs in children and
adolescents. Eighty-five percent of Ewing sarcoma is characterized by the
presence of the aberrant chimeric EWS/FLI1 fusion gene. Previously, we
demonstrated that an interaction between EWS/FLI1 and wild-type EWS led to the
inhibition of EWS activity and mitotic dysfunction. Although defective mitosis
is considered to be a critical step in cancer initiation, it is unknown how
interference with EWS contributes to Ewing sarcoma formation. Here, we
demonstrate that EWS/FLI1- and EWS-knockdown cells display a high incidence of
defects in the midzone, a midline structure located between segregating
chromatids during anaphase. Defects in the midzone can lead to the failure of
cytokinesis and can result in the induction of aneuploidy. The similarity among
the phenotypes of EWS/FLI1- and EWS siRNA-transfected HeLa cells points to the
inhibition of EWS as the key mechanism for the induction of midzone defects.
Supporting this observation, the ectopic expression of EWS rescues the high
incidence of midzone defects observed in Ewing sarcoma A673 cells. We discovered
that EWS interacts with Aurora B kinase, and that EWS is also required for
recruiting Aurora B to the midzone. A domain analysis revealed that the R565 in
the RGG3 domain of EWS is essential for both Aurora B interaction and the
recruitment of Aurora B to the midzone. Here, we propose that the impairment of
EWS-dependent midzone formation via the recruitment of Aurora B is a potential
mechanism of Ewing sarcoma development. |
List Hemolytic Uremic Syndrome Triad. | Hemolytic uremic syndrome (HUS) is a clinical syndrome characterized by the triad of anaemia, thrombocytopenia, renal failure. | Hemolytic uremic syndrome is a rare entity in patients with carcinoma and
presents with a triad of renal insufficiency, microangiopathic hemolytic anemia,
and thrombocytopenia. We report this syndrome for the first time in a patient
with small cell lung carcinoma. Spontaneous platelet aggregation of washed
normal platelets was demonstrated using patient plasma. Circulating immune
complex levels were not elevated. The entity completely resolved after treatment
with plasma, vincristine, aspirin, and dipyridamole. The hemolytic-uremic syndrome is a pathology characterized by a triad consisting
of acute renal failure, microangiopathic hemolytic anemia and thrombocytopenia,
with complications of the central nervous system arising in a considerable
number of cases. Altered cranial computerized tomography examinations usually
reveal cerebral infarctions. We present here two cases in which diffuse
hypodensity was observed in the white matter in addition to the infarcts. This
hypodensity was reversible after resolution of the acute phase of the disease,
as is also the case for the alterations described in uremic encephalopathy and
in hypertensive encephalopathy of other etiologies. Acute renal insufficiency in the setting of hemolysis and thrombocytopenia, a
triad that constitutes adult or pediatric hemolytic uremic syndrome, can be
associated with or triggered by diverse conditions such as
verocytotoxin-producing Escherichia coli, viral infections, pregcy, maligt
hypertension, scleroderma, renal radiation, allograft rejection, lupus
erythematosus, and assorted medications such as mitomycin C, cyclosporine, and
oral contraceptives. Recurrent and de novo hemolytic uremic syndrome occur after
renal transplantation. Relapses are also common and probably reflect incomplete
resolution of the initial episode. The major differential diagnoses of hemolytic
uremic syndrome in the renal allograft include acute vascular rejection,
cyclosporine, FK506 or antilymphocyte antibody nephrotoxicity, and maligt
hypertension, all of which may display overlapping clinical and histologic
features with primary hemolytic uremic syndrome; in such instances, the exact
diagnosis may be quite difficult. It is possible that the risk of recurrence may
be reduced by proper timing of transplantation and suitable choice of
immunosuppressive agents. Intensive plasmapheresis in conjunction with fresh
frozen plasma and supportive management of renal failure may lessen mortality
and morbidity even in recurrent hemolytic uremic syndrome after transplantation. CONTEXT: Hemolytic uremic syndrome is a rare condition compromising the clinical
triad of acute renal failure, microangiopathic hemolytic anemia, and
thrombocytopenia. Hemolytic uremic syndrome may be associated with a variety of
etiologies, and chemotherapeutic agents have also been reported to be associated
with hemolytic uremic syndrome, including mitomycin, cisplatin, bleomycin, and
most recently gemcitabine.
CASE REPORT: A 72-year-old Caucasian male treated with four cycles of
gemcitabine at 1,000 mg/m2 developed clinical and laboratory findings compatible
with hemolytic uremic syndrome. He developed microangiopathic hemolysis, rapidly
declining renal function with proteinuria and hematuria, and renal biopsy
revealed thrombotic microangiopathy. Hemodialysis, plasmapheresis, and
corticosteroid therapy were utilized but the process ultimately was
irreversible.
CONCLUSION: With multiple reports of hemolytic uremic syndrome complicating
gemcitabine therapy, it is imperative that clinicians heighten their awareness
of this potentially lethal complication. Hemolytic uremic syndrome (HUS) is a triad of microangiopathic hemolytic anemia,
thrombocytopenia, and acute renal failure. HUS is classified as either diarrhea
associated, most commonly caused by infection with Escherichia coli O157, or the
less common atypical HUS (aHUS), which may be familial or sporadic.
Approximately 50% of patients with aHUS have mutations in one of the complement
control proteins: factor H, factor I, or membrane cofactor protein (MCP). These
proteins regulate complement activation through cofactor activity, the
inactivation of C3b by limited proteolytic cleavage, a desirable event in the
fluid phase (no target) or on healthy self-tissue (wrong target). Complement
activation follows the endothelial cell injury that characterizes HUS. This
disease represents a model of what takes place when inappropriate complement
activation occurs on self-tissues due to the presence of mutated complement
regulatory proteins. Screening for mutations in factor H, factor I, or MCP is
expensive and time consuming. One approach is to perform antigenic screening for
factor H and factor I deficiency and to look for low levels of MCP (CD46)
expression by flow cytometry. Complement regulatory protein deficiency impacts
treatment decisions as patients with aHUS have a recurrence rate in renal
transplants of approximately 50%, whereas those with factor H mutations have an
even higher risk (approximately 80%). By contrast, MCP deficiency can be
corrected in part by a renal allograft. However, caution in the use of
live-related donations is needed because of the high rates of incomplete
penetrance of the described mutations. Hemolytic uremic syndrome is a triad of microangiopathic hemolytic anemia,
thrombocytopenia, and acute renal failure. It is one of a group of conditions
termed the thrombotic microangiopathies, which are characterized by prominent
endothelial cell injury. It may be diarrheal-associated or atypical (aHUS).
Evidence for a pathogenic role of the alternative pathway of complement was
first suggested in 1974. Mutations in the complement regulatory proteins factor
H, membrane cofactor protein (CD46), and factor I predispose to aHUS
development. Mutations of the activating components factor B and complement C3
have also been reported. Penetrance is approximately 50%, suggesting other
genetic and environmental modifiers are needed for disease expression.
Identification of mutations is important owing to differences in mortality,
renal survival, and outcome of renal transplantation. Current treatment is
plasma infusion/exchange, but complement inhibitor therapy provides hope for the
future. Hemolytic Uremic Syndrome (HUS) consists ofa triad of acquired hemolytic anemia,
thrombocytopenia, and renal failure that occurs acutely in otherwise healthy
individuals. HUS may be divided into two broad categories, typical, preceded by
a diarrheal prodrome, and atypical. The clinical symptoms of HUS as well as its
course, prognosis, and response to treatment appear to be significantly
influenced by a number of factors, including age at onset, type and severity of
underlying infections, and/or systemic diseases. A retrospective case series
review of five patients diagnosed with Hemolytic Uremic Syndrome at the
Pediatric University Hospital in Puerto Rico between 1997-2007 was performed.
The study showed that the incidence of HUS in children in Puerto Rico is lower
than other countries. However, the majority of cases have an atypical
presentation, which places our patients at higher risk for life-threatening
complications. BACKGROUND: Hemolytic uremic syndrome, one of the common causes of acute renal
failure in children, is characterized by the triad of microangiopathy,
haemolytic anemia, thrombocytopenia and acute renal failure. The
diarrhoea-associated Hemolytic uremic syndrome is usually termed as a typical
Hemolytic uremic syndrome. Streptococcus pneumoniae is an uncommon etiological
pathogen for inducing Hemolytic uremic syndrome, and Streptococcus pneumoniae
associated Hemolytic uremic syndrome is also termed as atypical hemolytic uremic
syndrome.
AIM: to report two pediatric cases of invasive S pneumoniae complicated with
hemolytic uremic syndrome HUS.
CASE REPORT: The first patient presented with pneumococcal pneumonia and empyema
and the second patient presented with pneumococcal pneumonia and meningitis. The
two patients were under one year of age and required peritoneal dialysis with
improvement of renal function in one; the other died.
CONCLUSION: Pneumococcal invasive disease may be a cause of severe HUS, so a
high index of suspicion is mandatory to prompt appropriate diagnosis and
management. BACKGROUND: Hemolytic uremic syndrome consists of a triad of acquired hemolytic
anemia, thrombocytopenia and renal failure.
AIM: Our objectives were to determine epidemiology, clinical and laboratory
characteristics of patients with atypical hemolytic uremic syndrome (aHUS) to
determine the relationship between the complement protein deficit and aHUS in
the Tunisian population.
METHODS: We studied retrospectively four cases of atypical HUS in adults
admitted in the Nephrology Department of Fattouma Bourguiba Universitary
Hospital in Monastir between 2000 and 2008.
RESULTS: Three patients had renal failure that required dialysis. One of them
received kidney transplantation with no further recurrence of aHUS. Three
patients had normal C3, C4, CFH, and FB levels, and in all patients anti-FH
autoantibodies were absent. The kidney biopsy of one patient showed in addition
to lupus glomerulonephritis histological findings consistent with TMA. A
decrease in C3, C4 and CFH levels in this patient was found both before and
after the cure.
CONCLUSION: Nephrologists should be aware of autoimmune conditions and genetic
abnormalities of the complement regulatory genes as possible pathogenic
mechanisms in atypical HUS patients. Hemolytic uremic syndrome (HUS) is a severe disease characterized by the
clinical triad of hemolytic anemia, thrombocytopenia, and acute renal failure.
HUS exists in two forms: the atypical diarrhea-negative HUS, which is often
associated with complement disorders, and the more frequent diarrheal-associated
typical HUS, which is caused by infections with enterohemorrhagic ESCHERICHIA
COLI. The virulence factors of the latter have been studied well, and Shiga
toxin (Stx)2 is reported to represent the most important one. In contrast, risk
factors on the host side have not been intensively studied until recently:
Complement activation products have been detected in the serum and plasma of HUS
patients, and an in vitro study could show that Stx2 not only damages the kidney
directly but also indirectly via complement, in two ways. First, it activates
complement, and second, it delays the functions of its control protein factor H
on the cell surface, both known to damage the kidney. BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is characterized by the
triad of microangiopathic hemolytic anemia, thrombocytopenia, and renal
impairment. Neonatal cases are extremely uncommon. Plasma therapy is the first
choice therapy in patients with aHUS based on the belief of an underlying
complement dysregulation. Alternatively, eculizumab, which targets complement 5,
is used to block complement activation.
CASE-DIAGNOSIS/TREATMENT: Sudden onset macroscopic hematuria, hypertension, and
bruises over the entire body were noted in a 5 day-old newborn. Investigations
revealed hemolytic anemia, thrombocytopenia, renal impairment, and a low serum
C3, leading to the diagnosis of aHUS. Fresh frozen plasma (FFP) infusions and
peritoneal dialysis for acute kidney injury were initiated. This approach
yielded full renal and hematological remission. The patient was discharged with
FFP infusions, but subsequently developed three life-threatening disease
recurrences at 1, 3, and 6 months of age. The last relapse presented with
uncontrolled hypertension and impaired renal function while the patient was
receiving FFP infusions. After the first dose of eculizumab, his renal and
hematological parameters returned to normal and his blood pressure normalized.
Genetic screening of the CFH gene revealed a novel homozygous p. Tyr1177Cys
mutation.
CONCLUSION: Eculizumab can be considered as an alternative to plasma therapy in
the treatment of specific patients with aHUS, even in infants. Hemolyitic uremic syndrome (HUS), characterized by triad of acute kidney injury,
thrombocytopenia, and hemolytic anemia, has considerable morbidity and mortality
and is known to be associated with diarrheal illness. It usually occurs after a
diarrheal illness due to Shiga-toxin-producing Escherichia coli. Streptococcus
pneumoniae is a rare but well recognized trigger for non-diarrhea associated HUS
in children, but has not been reported in adults. We report a case of an adult
presenting with pneumococcal pneumonia complicated by HUS and required renal
replacement therapy. Hemolytic uremic syndrome (HUS) is a triad of microangiopathic hemolytic anemia,
thrombocytopenia, and acute renal failure. The atypical form of HUS is a disease
characterized by complement overactivation. Inherited defects in complement
genes and acquired autoantibodies against complement regulatory proteins have
been described. Incomplete penetrance of mutations in all predisposing genes is
reported, suggesting that a precipitating event or trigger is required to unmask
the complement regulatory deficiency. The underlying genetic defect predicts the
prognosis both in native kidneys and after renal transplantation. The successful
trials of the complement inhibitor eculizumab in the treatment of atypical HUS
will revolutionize disease management. Hemolytic uremic syndrome (HUS) is a rare thrombotic complication characterized
by a triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute
renal failure. HUS may be caused by several different conditions, including
infection, maligcy, and chemotherapeutic agents, such as mitomycin,
cisplatin, and most recently, gemcitabine. The outcome of gemcitabine-induced
HUS is poor, and the disease has a high mortality rate. This study reports a
case of gemcitabine-induced HUS in a patient with pancreatic cancer in Korea. Atypical hemolytic uremic syndrome (aHUS) is rare and comprises the triad of
microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury.
Recently, abnormalities in the mechanisms underlying complement regulation have
been focused upon as causes of aHUS. The prognosis for patients who present with
aHUS is very poor, with the first aHUS attack being associated with a mortality
rate of approximately 25%, and with approximately 50% of cases resulting in
end-stage renal disease requiring dialysis. If treatment is delayed, there is a
high risk of this syndrome progressing to renal failure. Therefore, we have
developed diagnostic criteria for aHUS to enable its early diagnosis and to
facilitate the timely initiation of appropriate treatment. We hope these
diagnostic criteria will be disseminated to as many clinicians as possible and
that they will be used widely. Atypical hemolytic uremic syndrome (aHUS) is a relatively rare disorder
described by the triad of hemolytic anemia, thrombocytopenia, and renal failure.
Atypical HUS could be genetic, acquired, or idiopathic (without known genetic
changes or environmental triggers). Monoclonal protein has uncommonly been
reported as a cause of microangiopathic hemolytic anemia (MAHA). We report a
59-year-old white man who presented with acute kidney injury (AKI) with MAHA and
was given a diagnosis of aHUS with monoclonal gammopathy. His kidney function
and proteinuria worsened with persistent hemolysis despite eculizumab and later
cyclophosphamide and prednisone treatment. He responded well to VRD (bortezomib,
lenalidomide, and dexamethasone) regimen. Renal function, proteinuria, and
hemolysis all improved, and he was been in remission for more than 15 months. To
our knowledge, this is the first report of successful treatment with
bortezomib-based regimen for a patient with aHUS and monoclonal protein
refractory to eculizumab therapy. Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by the
triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal
failure. The term aHUS was historically used to distinguish this disorder from
Shiga-toxin producing Escherichia coli (STEC)-HUS. Many aHUS cases
(approximately 70%) are reportedly caused by uncontrolled complement activation
due to genetic mutations in the alternative pathway, including complement factor
H (CFH), complement factor I (CFI), membrane cofactor protein (MCP),
thrombomodulin (THBD), complement component C3 (C3), and complement factor B
(CFB). Mutations in the coagulation pathway, such as diacylglycerol kinase ε
(DGKE) and plasminogen, are also reported to be causes of aHUS. In this review,
we have focused on aHUS due to complement dysfunction. aHUS is suspected based
on plasma ADAMTS13 activity of 10% or more, and being negative for STEC-HUS, in
addition to the aforementioned triad. Complement genetic studies provide a more
specific diagnosis of aHUS. Plasma therapy is the first-line treatment for
patients with aHUS and should be initiated as soon as the diagnosis is
suspected. Recently, eculizumab, a humanized monoclonal antibody against C5, was
shown to be an effective treatment for aHUS. Therefore, early diagnosis and
identification of the underlying pathogenic mechanism is important for improving
the outcome of aHUS. Hemolytic uremic syndrome (HUS) is a clinical syndrome characterized by the
triad of thrombotic microangiopathy, thrombocytopenia, and acute kidney injury.
Hemolytic uremic syndrome represents a heterogeneous group of disorders with
variable etiologies that result in differences in presentation, management and
outcome. In recent years, better understanding of the HUS, especially those due
to genetic mutations in the alternative complement pathway have provided an
update on the terminology, classification, and treatment of the disease. This
review will provide the updated classification of the disease and the current
diagnostic and therapeutic approaches on the complement-mediated HUS in addition
to STEC-HUS which is the most common cause of the HUS in childhood. |
Does physical activity influence gut hormones? | Yes. | Syrian golden hamsters when allowed free access to food and an exercise wheel
will run long distances and develop hyperphagia and accelerated linear body
growth with high circulating levels of growth hormone and insulin. Somatostatin,
a widely distributed brain-gut neurohormonal peptide, modulates nutrient
absorption and may regulate food intake. To examine the role of circulating
plasma somatostatin-like immunoreactivity (SRIF-LI; pg/ml) in exercise induced
hyperphagia 4 groups of animals were studied; an unrestricted exercise group
(279.0 +/- 107.7, n = 10); a sedentary group (121.1 +/- 40.8, n = 8); a
restricted exercise group (107.7 +/- 12.4, n = 6); and a restricted no exercise
group (115.5 +/- 45.9, n = 9). Thus, the unrestricted exercise group has a
significantly elevated SRIF-LI concentration (P less than 0.01) while there was
no difference between the other 3 groups. The elevation of plasma SRIF-LI in the
unrestricted exercise group may represent a response to modulate increased
nutrient entry in this group or may represent an incompletely effective satiety
signal. Leptin, an ob gene product of adipocytes, plays a key role in the control of
food intake and energy expenditure but little is known about leptin response to
strenuous exercise in fasted and fed subjects or before and after blood
donation. This study was designed to determine the immediate effects of
strenuous exercise in healthy volunteers under fasting or fed conditions and
before and one day after blood donation (450 ml) on plasma levels of leptin and
gut hormones [gastrin, cholecystokinin (CCK), pancreatic polypeptide (PP) and
insulin], as well as on "stress" hormones (cortisol, catecholamines and growth
hormone. Two groups (A and B) of healthy non-smoking male volunteers were
studied. All subjects performed incremental exercise tests until exhaustion (up
to maximal oxygen uptake--VO2max), followed by 2 h of rest session. Group A
perfomed the tests on a treadmill, while group B on a cycloergometer. In group
A, one exercise was performed under fasting conditions and the second following
ingestion of a standard liquid meal. In group B, one exercise test was performed
as a control test and the second 24 h after blood donation (450 ml). Blood
samples were withdrawn 5 min before the start of the test, at the VO2max, and 2
h after finishing the exercise. No significant change in plasma teptin were
observed both immediately and 2 h after the exercise in fasted subjects, but
after the meal the plasma leptin at VO2max and 2 h after the test was
significantly higher, while after blood donation was significantly reduced. The
postprandial rise in plasma leptin was accompanied by a marked increment in gut
hormones; gastrin, CCK and PP and stress hormones such as norepinephrine,
cortisol and GH. These hormonal changes could contribute to the postprandial
rise in plasma leptin concentrations, while the fall of leptin after blood
donation could be attributed to the inadequate response of stress hormones and
autonomic nervous system to exhausting exercise. We conclude that strenuous
physical exercise; 1) fails to affect plasma leptin level but when performed
after meal but not after blood withdrawal it results in an increase and fall in
plasma leptin, and 2) the release of gut hormones (gastrin, CCK and PP) and
stress hormones (norepinephrine, cortisol, GH) increase immediately after
exercise independently of feeding or blood donation and 3) following blood
donation the strenuous exercise resulted in a marked reduction in the plasma
leptin, cortisol and GH concentrations, possibly due to the impairment in the
autonomic nervous control of these hormones. BACKGROUND: Although hormonal responses to exercise performed in fed state are
well documented, far less in known about the effect of a single exercise bout,
performed after overnight fasting, on cardio-respiratory responses and hormones
secretion. It has been reported that recently discovered hormones as leptin and
ghrelin may affect cardiovascular responses at rest. However, their effect on
the cardiovascular responses to exercise is unknown.
AIMS: This study was designed to determine the effect of overnight fasting on
cardio- respiratory responses during moderate incremental exercise. We have
hypothesised that fasting / exercise induced changes in plasma leptin / ghrelin
concentrations may influence cardiovascular response.
MATERIAL AND METHODS: Eight healthy non-smoking men (means +/- SE.: age 23.0 +/-
0.5 years; body mass 71.9 +/- 1.5 kg; height 179.1 +/- 0.8 cm; BMI 22.42 +/-
0.49 kg x m(-2) with VO2max of 3.71 +/- 0.10 l x min(-1)) volunteered for this
study. The subjects performed twice an incremental exercise test, with the
increase of power output by 30 W every 3 minutes. Tests were performed in a
random order: once in the feed state--cycling until exhaustion and second, about
one week later, after overnight fasting--cycling until reaching 150 W.
RESULTS: In the present study we have compared the results obtained during
incremental exercise performed only up to 150 W (59 +/- 2 % of VO2max) both in
fed and fasted state. Heart rate measured during exercise at each power output,
performed in fasted state was by about 10 bt x min(-1) (p = 0.02) lower then in
fed subjects. Respiratory quotient and plasma lactate concentration in fasted
state were also significantly (p<0.001) lower than in the fed state.
Pre-exercise plasma leptin and ghrelin concentrations were not significantly
different in fed and fasted state. Exercise induced increase in hGH was not
accompanied by a significant changes in the studied gut hormones such as
ghrelin, leptin, and insulin, except for plasma gastrin concentration, which was
significantly (p = 0.008) lower in fasting subjects at the power output of 150
W. Plasma [IL-6] at rest before exercise performed in fasted state was
significantly (p = 0.03) elevated in relation to the fed state. This was
accompanied by significantly higher (p = 0.047) plasma noradrenaline
concentration. Plasma IL-6 concentration at rest in fed subjects was negatively
correlated with plasma ghrelin concentration (r = -0.73, p < 0.05) and
positively correlated with plasma insulin concentration (r = 0.78, p < 0.05).
Significant negative correlation (r = -0.90; p < 0.05) was found between plasma
insulin and ghrelin concentration at rest in fed subjects.
CONCLUSIONS: We have concluded that plasma leptin and ghrelin concentrations
have no significant effect on the fasting-induced attenuation of heart rate
during exercise. We have postulated that this effect is caused by increased
plasma norepinephrine concentration, leading to the increase in systemic
vascular resistance and baroreceptor mediated vagal stimulation. Moreover we
believe, that the fasting-induced significant increase in plasma IL-6
concentration at rest, accompanied by higher plasma norepinephrine concentration
and lower RQ, belongs to the physiological responses, maintaining energy
homeostasis in the fasting state. BACKGROUND: Serum leptin variation is commonly associated with fat percentage
(%), body mass index (BMI), and activity. In this investigation, we report
population differences in mean leptin levels in healthy men as well as
associations with fat % and BMI that are independent of these factors and
reflect likely variation resulting from chronic environmental conditions.
METHODS: Serum leptin levels, fat %, and BMI were compared between lean American
distance runners and healthy Ache Native Americans of Paraguay. Mean levels were
compared as were the regressions between fat %, BMI, and leptin. Comparisons
were performed between male American distance runners (n = 13, mean age 32.2 +/-
9.2 SD) and highly active male New World indigenous population (Ache of
Paraguay, n = 20, mean age 32.8 +/- 9.2) in order to determine whether
significant population variation in leptin is evident in physically active
populations living under different ecological circumstances independent of
adiposity and BMI.
RESULTS: While the Ache were hypothesized to exhibit higher leptin due to
significantly greater adiposity (fat %, Ache 17.9 +/- 1.8 SD; runners 9.7 +/-
3.2, p < 0.0001), leptin levels were nonetheless significantly higher in
American runners (Ache 1.13 ng/ml +/- 0.38 SD; runners 2.19 +/- 1.15; p <
0.007). Significant differences in the association between leptin and fat % was
also evident between Ache and runner men. Although fat % was significantly
related with leptin in runners (r = 0.90, p < 0.0001) fat % was negatively
related in Ache men (r = -0.50, p < 0.03).
CONCLUSION: These results illustrate that chronic ecological conditions in
addition to activity are likely factors that contribute to population variation
in leptin levels and physiology. Population variation independent of adiposity
should be considered to be an important source of variation, especially in light
of ethnic and population differences in the incidence and etiology of obesity,
diabetes, and other metabolic conditions. This study investigated the acute effects of exercise on the postprandial levels
of appetite-related hormones and metabolites, energy intake (EI) and subjective
measures of appetite. Ghrelin, polypeptide YY (PYY), glucagon-like peptide-1
(GLP-1) and pancreatic polypeptide (PP) were measured in the fasting state and
postprandially in 12 healthy, normal-weight volunteers (six males and six
females) using a randomised crossover design. One hour after a standardised
breakfast, subjects either cycled for 60 min at 65% of their maximal heart rate
or rested. Subjective appetite was assessed throughout the study using visual
analogue scales and subsequent EI at a buffet meal was measured at the end (3-h
post-breakfast and 1-h post-exercise). Exercise significantly increased mean
PYY, GLP-1 and PP levels, and this effect was maintained during the
post-exercise period for GLP-1 and PP. No significant effect of exercise was
observed on postprandial levels of ghrelin. During the exercise period, hunger
scores were significantly decreased; however, this effect disappeared in the
post-exercise period. Exercise significantly increased subsequent absolute EI,
but produced a significant decrease in relative EI after accounting for the
energy expended during exercise. Hunger scores and PYY, GLP-1 and PP levels
showed an inverse temporal pattern during the 1-h exercise/control intervention.
In conclusion, acute exercise, of moderate intensity, temporarily decreased
hunger sensations and was able to produce a short-term negative energy balance.
This impact on appetite and subsequent energy homeostasis was not explained by
changes in postprandial levels of ghrelin; however, 'exercise-induced anorexia'
may potentially be linked to increased PYY, GLP-1 and PP levels. We examined whether changes in gut hormone levels due to a single bout of
aerobic exercise differ between obese young males and normal controls, and
attempted to determine the involvement of hormonal changes during exercise in
the regulation of energy balance (EB) in these obese subjects. Seven obese and
seven age-matched subjects of normal weight participated in exercise and rest
sessions. Subjects consumed a standardized breakfast that was followed by
constant cycling exercise at 50% VO(2max) or rest for 60 min. At lunch, a test
meal was presented, and energy intake (EI) and relative energy intake (REI) were
calculated. Blood samples were obtained at 30 min intervals during both sessions
for measurement of glucose, insulin, glucagon, ghrelin, peptide YY (PYY), and
glucagon-like peptide-1 (GLP-1). Plasma levels of PYY and GLP-1 were increased
by exercise, whereas plasma ghrelin levels were unaffected by exercise. The
areas under the curve (AUC) of the time courses of PYY and GLP-1 levels did not
significantly differ between the two groups. In contrast, EI and REI were
decreased by exercise in both groups, and energy deficit was significantly
larger in obese subjects than in normal controls. The present findings suggest
that short-term EB during a single exercise session might be regulated not by
increased amounts of these gut hormones per se. There is growing interest in the effects of exercise on plasma gut hormone
levels and subsequent energy intake (EI) but the effects of mode and exercise
intensity on anorectic hormone profiles on subsequent EI remain to be
elucidated. We aimed to investigate whether circulating peptide YY(3-36)
(PYY(3-36)) and glucagon-like peptide-1 (GLP-1 or GCG as listed in the HUGO
Database) levels depend on exercise intensity, which could affect subsequent EI.
Ten young male subjects (mean+/-s.d., age: 23.4+/-4.3 years, body mass index:
22.5+/-1.0 kg/m(2), and maximum oxygen uptake (VO(2 max)): 45.9+/-8.5 ml/kg per
min) received a standardized breakfast, which was followed by constant cycling
exercise at 75% VO(2 max) (high intensity session), 50% VO(2 max) (moderate
intensity session), or rest (resting session) for 30 min. At lunch, a test meal
was presented, and EI was calculated. Blood samples were obtained during three
sessions for measurements of glucose, insulin, PYY(3-36), and GLP-1, which
includes GLP-1 (7-36) amide and GLP-1 (9-36) amide. Increases in blood PYY(3-36)
levels were dependent on the exercise intensity (effect of session: P<0.001 by
two-way ANOVA), whereas those in GLP-1 levels were similar between two different
exercise sessions. Of note, increase in area under the curve values for GLP-1
levels was negatively correlated with decrease in the EI in each exercise
session (high: P<0.001, moderate: P=0.002). The present findings raise the
possibility that each gut hormone exhibits its specific blood kinetics in
response to two different intensities of exercise stimuli and might play
differential roles in regulation of EI after exercise. BACKGROUND: Short-term physical inactivity affects energy balance and is
considered conducive to weigh gain. Long-term effects are unknown.
OBJECTIVE: The objective of the study was to use a bed-rest model to determine
the long-term effects of physical inactivity on energy balance regulation and
test the effect of exercise training on energy balance adjustment to physical
inactivity.
DESIGN: Sixteen lean women were divided into two groups (n = 8 each): a control
group subjected to a strict 60-d bed rest and an exercise group subjected to a
combined aerobic/resistive exercise training concomitantly to bed rest. Body
composition, spontaneous energy intake, hunger, total energy expenditure (TEE),
and fasting gut hormones were measured.
RESULTS: Based on bed-rest-induced body composition changes, the control group
were in slight negative energy balance (-0.4 +/- 0.4 MJ/d; P = 0.01 vs. zero),
essentially due to muscle atrophy (P < 0.001 vs. zero). The stable fat mass (P =
0.19 vs. zero), and the matching between spontaneous energy intake and TEE
indicated, however, a stable energy balance. Hunger and gut hormones remained
unchanged during the bed rest. In the exercise group, TEE was 24% higher than in
the control group (P = 0.004). Unexpectedly, desire to consume food (P = 0.025)
decreased and spontaneous energy intake (P = NS) was not stimulated, promoting a
negative energy balance (-1.1 +/- 0.5 MJ/d, P = 0.0003 vs. zero).
CONCLUSIONS: Energy balance is regulated during 2 months of physical inactivity,
contrasting with short-term experiments. Conversely, exercise-induced energy
expenditure in bed-resting subjects who have no spontaneous physical activity
did not induce hunger and promoted a negative energy balance, suggesting a
potential role of nonexercise physical activities in energy balance regulation. Recent studies suggest that spontaneous physical activity (SPA) may be under the
non-conscious control of neuroendocrine circuits that are known to control food
intake. To further elucidate endocrine gut-brain communication as a component of
such circuitry, we here analyzed long-term and acute effects of the
gastrointestinal hormones ghrelin and PYY 3-36 as well as their hypothalamic
neuropeptide targets NPY, AgRP and POMC (alpha-MSH), on locomotor activity and
home cage behaviors in rats. For the analysis of SPA, we used an automated
infrared beam break activity measuring system, combined with a novel automated
video-based behavior analysis system (HomeCageScan (HCS)). Chronic (one-month)
peripheral infusion of ghrelin potently increased body weight and fat mass in
rats. Such positive energy balance was intriguingly not due to an overall
increased caloric ingestion, but was predomitly associated with a decrease in
SPA. Chronic intracerebroventricular infusion (7 days) of ghrelin corroborated
the decrease in SPA and suggested a centrally mediated mechanism. Central
administration of AgRP and NPY increased food intake as expected. AgRP
administration led to a delayed decrease in SPA, while NPY acutely (but
transiently) increased SPA. Behavioral dissection using HCS corroborated the
observed acute and transient increases of food intake and SPA by central NPY
infusion. Acute central administration of alpha-MSH rapidly decreased food
intake but did not change SPA. Central administration of the NPY receptor
agonist PYY 3-36 transiently increased SPA. Our data suggest that the control of
spontaneous physical activity by gut hormones or their neuropeptide targets may
represent an important mechanistic component of energy balance regulation. Ghrelin and peptide YY (PYY) are newly recognized gut peptides involved in
appetite regulation. Plasma ghrelin concentrations are elevated in fasting and
suppressed following a meal, while PYY concentrations are suppressed in fasting
and elevated postprandially. We determine whether ghrelin and PYY are altered by
a low-fat, high-carbohydrate (10% fat, 75% carbohydrate) or moderate-fat,
moderate-carbohydrate (35% fat, 50% carbohydrate) diet and; whether these
peptides are affected by intense endurance running (which is likely to
temporarily suppress appetite). Twenty-one endurance-trained runners followed a
controlled diet (25% fat) and training regimen for 3 days before consuming the
low-fat or isoenergetic moderate-fat diet for another 3 days in random
cross-over fashion. On day 7 runners underwent glycogen restoration and then
completed a 90-minute pre-loaded 10-km time trial on day 8, following a control
breakfast. Blood samples were obtained on days 4 and 7 (fasting), and day 8
(non-fasting) before and after exercise for analysis of ghrelin, PYY, insulin
and growth hormone (GH). Insulin, GH, Ghrelin and PYY changed significantly over
time (p < 0.0001) but were not influenced by diet. Ghrelin was elevated during
fasting (days 4 and 7), while insulin and PYY were suppressed. Following the
pre-exercise meal, ghrelin was suppressed ~17% and insulin and PYY were elevated
~157 and ~40%, respectively, relative to fasting (day 7). Following exercise,
PYY, ghrelin, and GH were significantly (p < 0.0001) increased by ~11, ~16 and
~813%, respectively. The noted disruption in the typical inverse relationship
between ghrelin and PYY following exercise suggests that interaction of these
peptides may be at least partially responsible for post-exercise appetite
suppression. These peptides do not appear to be influenced by dietary fat
intake. Nine female runners and ten walkers completed a 60 min moderate-intensity (70%
VO(2)max) run or walk, or 60 min rest in counterbalanced order. Plasma
concentrations of the orexogenic peptide ghrelin, anorexogenic peptides peptide
YY (PYY), glucagon-like peptide-1 (GLP-1), and appetite ratings were measured at
30 min interval for 120 min, followed by a free-choice meal. Both orexogenic and
anorexogenic peptides were elevated after running, but no changes were observed
after walking. Relative energy intake (adjusted for cost of exercise/rest) was
negative in the meal following running (-194 ± 206 kcal) versus walking (41 ±
196 kcal) (P = 0.015), although both were suppressed (P < 0.05) compared to rest
(299 ± 308 and 284 ± 121 kcal, resp.). The average rate of change in PYY and
GLP-1 over time predicted appetite in runners, but only the change in GLP-1
predicted hunger (P = 0.05) in walkers. Results provide evidence that
exercise-induced alterations in appetite are likely driven by complex changes in
appetite-regulating hormones rather than change in a single gut peptide. Sprint interval exercise improves several health markers but the appetite and
energy balance response is unknown. This study compared the effects of sprint
interval and endurance exercise on appetite, energy intake and gut hormone
responses. Twelve healthy males [mean (SD): age 23 (3) years, body mass index
24.2 (2.9) kg m(-2), maximum oxygen uptake 46.3 (10.2) mL kg(-1) min(-1)]
completed three 8 h trials [control (CON), endurance exercise (END), sprint
interval exercise (SIE)] separated by 1 week. Trials commenced upon completion
of a standardised breakfast. Sixty minutes of cycling at 68.1 (4.3) % of maximum
oxygen uptake was performed from 1.75-2.75 h in END. Six 30-s Wingate tests were
performed from 2.25-2.75 h in SIE. Appetite ratings, acylated ghrelin and
peptide YY (PYY) concentrations were measured throughout each trial. Food intake
was monitored from buffet meals at 3.5 and 7 h and an overnight food bag.
Appetite (P < 0.0005) and acylated ghrelin (P < 0.002) were suppressed during
exercise but more so during SIE. Peptide YY increased during exercise but most
consistently during END (P < 0.05). Acylated ghrelin was lowest in the afternoon
of SIE (P = 0.018) despite elevated appetite (P = 0.052). Exercise energy
expenditure was higher in END than that in SIE (P < 0.0005). Energy intake was
not different between trials (P > 0.05). Therefore, relative energy intake
(energy intake minus the net energy expenditure of exercise) was lower in END
than that in CON (15.7 %; P = 0.006) and SIE (11.5 %; P = 0.082). An acute bout
of endurance exercise resulted in lower appetite perceptions in the hours after
exercise than sprint interval exercise and induced a greater 24 h energy deficit
due to higher energy expenditure during exercise. The present study determined the changes in appetite and appetite-regulating gut
hormones during and following bouts of both rope skipping exercise
(weight-bearing) and bicycle ergometer exercise (non-weight-bearing). After a
12-h fast, 15 young men (mean ± SD, age 24.4 ± 1.7 yrs, maximal oxygen uptake
47.0 ± 6.5 mL/kg/min) participated in three 160 min trials: (1) rope skipping
exercise (295 ± 40 kcal, 3 sets × 10 min with 5-min interval, then rested for
120 min); (2) bicycle ergometer exercise (288 ± 36 kcal, 3 sets × 10 min with
5-min interval, then rested for 120 min); (3) control (rested for 160 min).
Ratings of perceived hunger and acylated ghrelin were suppressed and total
peptide YY (PYY) were increased during and immediately after exercise in both
exercise trials, but glucagon liked peptide-1 was not changed. Furthermore,
suppressed hunger during rope skipping exercise was greater than that during
bicycle ergometer exercise, but there were no differences in acylated ghrelin
and total PYY. These results indicate that weight-bearing exercise has a greater
exercise-induced appetite suppressive effect compared with non-weight-bearing
exercise, and both forms of exercise lowered acylated ghrelin and increased
total PYY, but the changes did not differ significantly between exercise modes. |
What are the effects of depleting protein km23-1 (DYNLRB1) in a cell? | The knockdown of km23-1 results in numerous effects at the cellular level, such as decreased cell migration. Additionaly, km23-1 is involved in signalling pathways and its knockdown results in decreased RhoA activation, inhibition of TGFβ-mediated activation of ERK and JNK, phosphorylation of c-Jun, transactivation of the c-Jun promoter and decreased TGFbeta responses. | We previously identified km23 as a novel TGFbeta receptor-interacting protein.
Here we show that km23 is ubiquitously expressed in human tissues and that
cell-type specific differences in endogenous km23 protein expression exist. In
addition, we demonstrate that the phosphorylation of km23 is TGFbeta-dependent,
in that EGF was unable to phosphorylate km23. Further, the kinase activity of
both TGFbeta receptors appears to play a role in the TGFbeta-mediated
phosphorylation of km23, although TGFbeta RII kinase activity is absolutely
required for km23 phosphorylation. Blockade of km23 using small interfering RNAs
significantly decreased key TGFbeta responses, including induction of
fibronectin expression and inhibition of cell growth. Thus, our results
demonstrate that km23 is required for TGFbeta induction of fibronectin
expression and is necessary, but not sufficient, for TGFbeta-mediated growth
inhibition. PURPOSE: A very high frequency of somatic mutations in the transforming growth
factor-beta signaling component km23 has been reported in a small series of
ovarian cancers (8 of 19, 42%). Functional studies showed that some mutations
disrupt km23 function, resulting in aberrant transforming growth factor-beta
signaling and presumably enhanced tumorigenicity. If verified, this would
elevate mutation of km23 as the single most frequent somatic event in ovarian
cancer.
EXPERIMENTAL DESIGN: We sought to verify the frequency of silencing of km23
among 104 primary ovarian cancers (49 serous, 18 mucinous, 29 endometrioid/clear
cell, and 8 undifferentiated) as well as 72 breast and 61 colorectal cancers by
undertaking both somatic mutation and promoter methylation analyses. All four
exons of km23 were individually amplified from genomic DNA with primers
complementary to surrounding intronic sequences and analyzed by single-stranded
conformational polymorphism analysis.
RESULTS: Two germ line polymorphisms were identified, but none of the 237 tumors
analyzed harbored somatic km23 mutations. In addition, promoter methylation
analysis showed that in all cases, the 5' CpG island was unmethylated.
CONCLUSIONS: Our data suggest that silencing of km23, either through somatic
genetic mutation or promoter hypermethylation, is rare in ovarian, breast, and
colorectal cancers. The reduced folate carrier (RFC) is a major folate transport system in mammalian
cells. RFC is highly expressed in the intestine and believed to play a role in
folate absorption. Studies from our laboratory and others have characterized
different aspects of the intestinal folate absorption process, but little is
known about possible existence of accessory protein(s) that interacts with RFC
and influences its physiology and/or cell biology. We investigated this issue by
employing a bacterial two-hybrid system to screen a BacterioMatch II human
intestinal cDNA library using the large intracellular loop between transmembrane
domains 6 and 7 of the human RFC (hRFC) as bait. Our screening has resulted in
the identification of dynein light chain road block-1 (DYNLRB1) as an
interacting partner with hRFC. Existence of a direct protein-protein interaction
between hRFC and DYNLRB1 was confirmed by in vitro pull-down assay and in vivo
mammalian two-hybrid luciferase assay and coimmunoprecipitation analysis.
Furthermore, confocal imaging of live human intestinal epithelial HuTu-80 cells
demonstrated colocalization of DYNLRB1 with hRFC. Coexpression of DYNLRB1 with
hRFC led to a significant (P < 0.05) increase in folate uptake. On the other
hand, inhibiting the endogenous DYNLRB1 with gene-specific small interfering RNA
or pharmacologically with a specific inhibitor (vanadate) led to a significant
(P < 0.05) decrease in folate uptake. This study demonstrates for the first time
the identification of DYNLRB1 as an interacting protein partner with hRFC.
Furthermore, DYNLRB1 appears to influence the function and cell biology of hRFC. We have previously reported that the dynein light chain (DLC) km23-1 is required
for Smad2-dependent TGFbeta signaling. Here we describe another member of the
km23/DYNLRB/LC7/robl family of DLCs, termed km23-2, which is also involved in
TGFbeta signaling. We show not only that TGFbeta stimulates the interaction of
km23-2 (DYNLRB2) with TGFbeta receptor II (TbetaRII) but also that TGFbeta
regulates the interaction between km23-2 and endogenous TbetaRII in vivo. In
addition, TGFbeta treatment causes km23-2 phosphorylation, whereas a
kinase-deficient form of TbetaRII prevents km23-2 phosphorylation. In contrast
to the km23-1 isoform, blockade of km23-2 expression using small interfering
RNAs (siRNAs) decreased key TGFbeta/Smad3-specific responses, including the
induction of both plasminogen activator inhibitor-1 (PAI-1) gene expression and
p21 protein expression. Blockade of km23-1 expression had no effect on these two
major TGFbeta/Smad3 responses under similar conditions. Further, km23-2 was
required for TGFbeta stimulation of Smad3-dependent Smad-binding element
(SBE)2-Luc transcriptional activity, but not for TGFbeta stimulation of
Smad2-dependent activin responsive element (ARE)-Lux transcriptional activity.
In order to assess the mechanisms underlying the preferential stimulation of
Smad3- versus Smad2-specific TGFbeta responses, immunoprecipitation (IP)/blot
analyses were performed, which demonstrate that TGFbeta stimulated preferential
complex formation of km23-2 with Smad3, relative to Smad2. Collectively, our
findings indicate that km23-2 is required for Smad3-dependent TGFbeta signaling.
More importantly, we demonstrate that km23-2 has functions in TGFbeta signaling
that are distinct from those for km23-1. This is the first report to describe a
differential requirement for unique isoforms of a specific DLC family in
Smad-specific TGFbeta signaling. km23-1 was originally identified as a TGFß receptor-interacting protein that
plays an important role in TGFß signaling. Moreover, km23-1 is actually part of
an ancient superfamily of NTPase-regulatory proteins, widely represented in
archaea and bacteria. To further elucidate the function of km23-1, we identified
novel protein interacting partners for km23-1 by using tandem affinity
purification (TAP) and tandem mass spectrometry (MS). Here we show that km23-1
interacted with a class of proteins involved in actin-based cell motility and
modulation of the actin cytoskeleton. We further showed that km23-1 modulates
the formation of a highly organized stress fiber network. More significantly, we
demonstrated that knockdown (KD) of km23-1 decreased RhoA activation in Mv1Lu
epithelial cells. Finally, our results demonstrated for the first time that
depletion of km23-1 inhibited cell migration of human colon carcinoma cells
(HCCCs) in wound-healing assays. Overall, our findings demonstrate that km23-1
regulates RhoA and motility-associated actin modulating proteins, suggesting
that km23-1 may represent a novel target for anti-metastatic therapy. |
Treatment of which disease was investigated in the MR CLEAN study? | Multicenter Randomized CLinical trial of Endovascular treatment for Acute ischemic stroke in the Netherlands (MR CLEAN) study investigated endovascular treatment for acute ischemic stroke. | In 3 recent randomized controlled trials of intra-arterial treatment of acute
ischemic stroke - IMS-III, SYNTHESIS and MR RESCUE - intra-arterial treatment
increased the proportion of patients with recanalization and the treatment
appeared safe. However, the trials did not show an effect on functional
recovery, although a substantial effect could not be excluded. The delay between
onset of symptoms and treatment was long, and stent retrievers were used in only
a few patients. In our view, a rational and ethical approach would now be to
treat quickly with IV rtPA and when possible, refer and include in new
randomized clinical trials that compare intra-arterial treatment with standard
care, such as MR CLEAN or BASICS in the Netherlands. BACKGROUND: Endovascular or intra-arterial treatment (IAT) increases the
likelihood of recanalization in patients with acute ischemic stroke caused by a
proximal intracranial arterial occlusion. However, a beneficial effect of IAT on
functional recovery in patients with acute ischemic stroke remains unproven. The
aim of this study is to assess the effect of IAT on functional outcome in
patients with acute ischemic stroke. Additionally, we aim to assess the safety
of IAT, and the effect on recanalization of different mechanical treatment
modalities.
METHODS/DESIGN: A multicenter randomized clinical trial with blinded outcome
assessment. The active comparison is IAT versus no IAT. IAT may consist of
intra-arterial thrombolysis with alteplase or urokinase, mechanical treatment or
both. Mechanical treatment refers to retraction, aspiration, sonolysis, or use
of a retrievable stent (stent-retriever). Patients with a relevant intracranial
proximal arterial occlusion of the anterior circulation, who can be treated
within 6 hours after stroke onset, are eligible. Treatment effect will be
estimated with ordinal logistic regression (shift analysis); 500 patients will
be included in the trial for a power of 80% to detect a shift leading to a
decrease in dependency in 10% of treated patients. The primary outcome is the
score on the modified Rankin scale at 90 days. Secondary outcomes are the
National Institutes of Health stroke scale score at 24 hours, vessel patency at
24 hours, infarct size on day 5, and the occurrence of major bleeding during the
first 5 days.
DISCUSSION: If IAT leads to a 10% absolute reduction in poor outcome after
stroke, careful implementation of the intervention could save approximately 1%
of all new stroke cases from death or disability annually.
TRIAL REGISTRATION: NTR1804 (7 May 2009)/ISRCTN10888758 (24 July 2012). INTRODUCTION: A recent randomized controlled trial (RCT), the Multicenter
Randomized CLinical trial of Endovascular treatment for Acute ischemic stroke in
the Netherlands (MR CLEAN), demonstrated better outcomes with endovascular
treatment compared with medical therapy for acute ischemic stroke (AIS).
However, previous trials have provided mixed results regarding the efficacy of
endovascular treatment for AIS. A meta-analysis of all available trial data was
performed to summarize the available evidence.
METHODS: A literature search was performed to identify all prospective RCTs
comparing endovascular therapies with medical management for AIS. Two datasets
were created: (1) all patients randomized after confirmation of large vessel
occlusion (LVO) (consistent with the contemporary standard of practice at the
majority of centers); and (2) all patients with outcome data who underwent
randomization regardless of qualifying vascular imaging. The pre-specified
primary outcome measure was modified Rankin Scale score of 0-2 at 90 days. A
fixed-effect model was used to determine significance.
RESULTS: Five prospective RCTs comparing endovascular therapies with medical
management were included in dataset 1 (1183 patients) and six were included in
dataset 2 (1903 total patients). Endovascular therapies were associated with
significantly improved outcomes compared with medical management (OR 1.67, 95%
CI 1.29 to 1.16, p=0.0001) for patients with LVO (dataset 1). This benefit
persisted when patients from all six RCTs were included, even in the absence of
confirmation of LVO (OR 1.27, 95% CI 1.05 to 1.54, p=0.019; dataset 2).
CONCLUSIONS: A meta-analysis of prospective RCTs comparing endovascular
therapies with medical management demonstrates superior outcomes in patients
randomized to endovascular therapy. BACKGROUND: In patients with acute ischemic stroke caused by a proximal
intracranial arterial occlusion, intraarterial treatment is highly effective for
emergency revascularization. However, proof of a beneficial effect on functional
outcome is lacking.
METHODS: We randomly assigned eligible patients to either intraarterial
treatment plus usual care or usual care alone. Eligible patients had a proximal
arterial occlusion in the anterior cerebral circulation that was confirmed on
vessel imaging and that could be treated intraarterially within 6 hours after
symptom onset. The primary outcome was the modified Rankin scale score at 90
days; this categorical scale measures functional outcome, with scores ranging
from 0 (no symptoms) to 6 (death). The treatment effect was estimated with
ordinal logistic regression as a common odds ratio, adjusted for prespecified
prognostic factors. The adjusted common odds ratio measured the likelihood that
intraarterial treatment would lead to lower modified Rankin scores, as compared
with usual care alone (shift analysis).
RESULTS: We enrolled 500 patients at 16 medical centers in The Netherlands (233
assigned to intraarterial treatment and 267 to usual care alone). The mean age
was 65 years (range, 23 to 96), and 445 patients (89.0%) were treated with
intravenous alteplase before randomization. Retrievable stents were used in 190
of the 233 patients (81.5%) assigned to intraarterial treatment. The adjusted
common odds ratio was 1.67 (95% confidence interval [CI], 1.21 to 2.30). There
was an absolute difference of 13.5 percentage points (95% CI, 5.9 to 21.2) in
the rate of functional independence (modified Rankin score, 0 to 2) in favor of
the intervention (32.6% vs. 19.1%). There were no significant differences in
mortality or the occurrence of symptomatic intracerebral hemorrhage.
CONCLUSIONS: In patients with acute ischemic stroke caused by a proximal
intracranial occlusion of the anterior circulation, intraarterial treatment
administered within 6 hours after stroke onset was effective and safe. (Funded
by the Dutch Heart Foundation and others; MR CLEAN Netherlands Trial Registry
number, NTR1804, and Current Controlled Trials number, ISRCTN10888758.). |
Which factors activate zygotic gene expression during the maternal-to-zygotic transition in zebrafish? | Nanog, Pou5f1 and SoxB1 activate zygotic gene expression during the maternal-to-zygotic transition. Maternal Nanog, Pou5f1 and SoxB1 are required to initiate the zygotic developmental program and induce clearance of the maternal program by activating miR-430 expression. | After fertilization, maternal factors direct development and trigger zygotic
genome activation (ZGA) at the maternal-to-zygotic transition (MZT). In
zebrafish, ZGA is required for gastrulation and clearance of maternal messenger
RNAs, which is in part regulated by the conserved microRNA miR-430. However, the
factors that activate the zygotic program in vertebrates are unknown. Here we
show that Nanog, Pou5f1 (also called Oct4) and SoxB1 regulate zygotic gene
activation in zebrafish. We identified several hundred genes directly activated
by maternal factors, constituting the first wave of zygotic transcription.
Ribosome profiling revealed that og, sox19b and pou5f1 are the most highly
translated transcription factors pre-MZT. Combined loss of these factors
resulted in developmental arrest before gastrulation and a failure to activate
>75% of zygotic genes, including miR-430. Our results demonstrate that maternal
Nanog, Pou5f1 and SoxB1 are required to initiate the zygotic developmental
program and induce clearance of the maternal program by activating miR-430
expression. |
Is irritable bowel syndrome more common in women with endometriosis? | Yes, irritable bowel syndrome (IBS) is more common in women with endometriosis. It has been shown that 15% of the patients with endometriosis also had IBS. Women with endometriosis are more likely to have received a diagnosis of IBS. Endometriosis may coexist with or be misdiagnosed as IBS. | Both irritable bowel syndrome and endometriosis are common conditions, although
symptomatic gastrointestinal endometriosis is extremely rare. We report the case
of a patient initially thought to have irritable bowel syndrome, in whom the
diagnosis of endometriosis only became clear following a laparotomy for small
bowel obstruction. This case highlights the need to question the diagnosis in
patients with irritable bowel syndrome when there is any uncertainty, and also
to appreciate that other pathology can arise, even when the diagnosis is secure. Chronic symptoms of abdominal pain and irregular bowel habits in women evoke a
broad differential diagnosis including irritable bowel syndrome, infection,
malabsorption, and inflammatory bowel disease. Endometriosis, a common disorder
in young women that can involve the intestinal tract, deserves consideration as
well. Intestinal endometriosis is typically asymptomatic; however, when symptoms
occur, they can mimic those of irritable bowel syndrome. Identifying intestinal
endometriosis can be challenging, but historical points and key clinical
features aid in diagnosis. OBJECTIVE: Authors report their experience about a case of intestinal
endometriosis that lead cyclic and recurrent rectal bleeding in a fertile-age
woman.
DESIGN: Report of 1 case with multidisciplinary approach and surgical treatment.
Surgical effectiveness evaluation and 2 years follow-up. Brief review on the
recent literature and the diagnostic and therapeutic implications.
SETTING: Section of General and Thoracic Surgery, Department of General Surgery,
Emergency and Organ Transplantation, Policlinico "Paolo Giaccone", Palermo.
INTERVENTION: After correct and sure diagnosis, the patient was submitted to
sigmoid segmental resection with radical and curative intention.
RESULTS: Complete recovery. Follow-up (24 months) negative.
CONCLUSIONS: Diagnosis of endometriosis should be considered in women with
recurrent monthly abdominal pain and bowel symptoms, especially if accompanied
by gynaecologic complaints, even because the significant symptoms overlap with
the irritable bowel syndrome (IBS) and makes the differentiation extremely
difficult. Treatment of GI endometriosis is best approached in collaboration
between gynaecologist experienced and intestinal surgeon. The high accuracy and
low complications suggested that EUS-FNA was effective for the correct
histologic diagnosis of intestinal endometriosis. The objective of this short review is to identify the particularities of women
with endometriosis, especially those complaining of pain and with the most
severe lesions. Genetic aberrations play, with a high probability, a major role
in the development of this disease, its severity, its tendency to recur and also
in its capacity to degenerate. The abnormalities of the endometrium, with
exacerbated biological activities, are an example. The woman with endometriosis
seems more sensitive to pain through various mechanisms, such as central
hypersensitivity and decrease threshold to somatoceptive pain and several
associated psychological disorders. Endometriosis is often associated with other
painful conditions such as irritable bowel syndrome, interstitial cystitis and
fibromyalgia. Finally, also appears also to have a higher risk to develop non
Hodgkin's lymphoma or ovarian cancer. These particularities, some of them being
still speculative or controversial, should be known in routine practise, in
order to offer a better multidisciplinary management, not only for short term,
but also long term issues. Endometriosis is defined as the presence of endometrial tissue outside the
uterus. The bowel is not often affected. There are no specific clinical findings
for intestinal endometriosis. It is typically asymptomatic, but sometimes can
present with abdominal pain, diarrhoea, constipation or intestinal obstruction.
Ileal perforation is a rare complication of intestinal endometriosis and only a
few cases have been reported in the literature. Intestinal endometriosis can
mimic many gastrointestinal diseases, such as irritable bowel syndrome,
inflammatory bowel disease, infections and neoplasms. The diagnosis is made by
laparoscopy or laparotomy. We present a case of a woman with intermittent
abdominal pain and ileal perforation secondary to intestinal endometriosis. OBJECTIVE: To examine the headache characteristics of women with migraine and
endometriosis (EM), and differences in the prevalence of comorbid conditions
between female migraineurs with EM, without EM and nonheadache controls.
BACKGROUND: Migraine and EM are common conditions in women of reproductive age,
and both are influenced by ovarian hormones. The comorbidity of migraine and EM
is newly recognized, but reasons for the association are uncertain.
METHODS: This is a cross-sectional study of female headache outpatients and
healthy controls conducted at University of Toledo and Duke University in 2005
and 2006. After a headache specialist determined headache frequency and
diagnosis (based on criteria of the second International Classification of
Headache Disorders), patients completed a self-administered electronic survey
with information on demographics, headache-related disability, menstrual
disorders, premenstrual dysphoric disorder (PMDD), vascular event risk, and
comorbid conditions, including irritable bowel syndrome (IBS), fibromyalgia
(FM), chronic fatigue syndrome (CFS), interstitial cystitis (IC), depression,
and anxiety.
RESULTS: Study enrolled 171 women with migraine and 104 controls. EM was
reported more commonly in migraineurs than in controls (22% vs 9.6%, P < .01).
Frequency of chronic headache was higher in migraineurs with EM compared to
without EM (P= .002) and median headache-related disability scores were also
higher in the EM group (P= .025). Symptoms of PMDD were more common in
migraineurs, but frequency did not differ by EM status. Migraineurs with EM
reported more menorrhagia, dysmenorrhea, and infertility compared to the
migraine cohort without EM and to controls. Depression, anxiety, IBS, FM, CFS,
and IC were more common in migraine with EM group than in controls. Anxiety (OR
= 2.2, 95% CI 1.0-4.7), IC (OR = 10.6, 95% CI 1.9-56.5), and CFS (OR = 3.6, 95%
CI 1.1-11.5) were more common in migraine with EM group, than in the cohort with
migraine without EM.
CONCLUSION: Prevalence of EM is higher in women with migraine than in
nonheadache controls. Migraineurs with EM have more frequent and disabling
headaches, and are more likely to have other comorbid conditions affecting mood
and pain, compared to migraineurs without EM. Rectovaginal endometriosis is a severe variant of endometriosis. Common
presenting symptoms for endometriosis include dysmenorrhoea, pelvic pain and
dyspareunia. It is now recognised that there are other less traditional symptoms
of endometriosis that are also relatively common. The aim of this study is to
assess the relative strength of each of the potential symptoms of rectovaginal
endometriosis and compare these with the laparoscopic and histological findings.
In this retrospective, observational study the overall prevalence of
rectovaginal endometriosis in the group was 31.4%. The presence of dyschesia
gave a likelihood ratio of 1.27 (95% CI: 0.56 - 2.89) with a predictive
prevalence of rectovaginal endometriosis of 37%. Apareunia and nausea or
abdominal bloating were particularly strong markers for rectovaginal disease
with a predictive prevalence of 87% and 89%, respectively. The classical
symptoms often attributed to irritable bowel syndrome are also common in women
with rectovaginal disease. In women, clinical studies suggest that functional pain syndromes such as
irritable bowel syndrome, interstitial cystitis, and fibromyalgia, are co-morbid
with endometriosis, chronic pelvic pain, and others diseases. One of the
possible explanations for this phenomenon is visceral cross-sensitization in
which increased nociceptive input from inflamed reproductive system organs
sensitize neurons that receive convergent input from an unaffected visceral
organ to the same dorsal root ganglion (DRG). The purpose of this study was to
determine whether primary sensory neurons that innervate both visceral
organs--the uterus and the colon--express nociceptive ATP-sensitive purinergic
(P2X3) and capsaicin-sensitive vanilloid (TRPV1) receptors. To test this
hypothesis, cell bodies of colonic and uterine DRG were retrogradely labeled
with fluorescent tracer dyes micro-injected into the colon/rectum and uterus of
rats. Ganglia were harvested, cryo-protected, and cut in 20-microm slices for
fluorescent microscopy to identify positively stained cells. Up to 5% neurons
were colon-specific or uterus-specific, and 10%-15% of labeled DRG neurons
innervate both viscera in the lumbosacral neurons (L1-S3 levels). We found that
viscerally labeled DRGs express nociceptive P2X3 and TRPV1 receptors. Our
results suggest a novel form of visceral sensory integration in the DRG that may
underlie co-morbidity of many functional pain syndromes. BACKGROUND: Endometriosis commonly presents with a range of symptoms none of
which are particularly specific for the condition, often resulting in
misdiagnosis or delay in diagnosis.
AIM: To investigate gastrointestinal symptoms in women with endometriosis and
compare their frequency with that of the classical gynaecological symptoms.
METHODS: Systematic exploration of symptoms in a consecutive series of 355 women
undergoing operative laparoscopy for suspected endometriosis.
RESULTS: Endometriosis was confirmed by histology in 290 women (84.5%). Bowel
lesions were present in only 7.6%. Ninety per cent of women had gastrointestinal
symptoms, of which bloating was the most common (82.8%), but 71.3% also had
other bowel symptoms. All gastrointestinal symptoms were similarly predictive of
histologically confirmed endometriosis. Seventy-six women (21.4%) had previously
been diagnosed with irritable bowel syndrome and 79% of them had endometriosis
confirmed.
CONCLUSION: Gastrointestinal symptoms are nearly as common as gynaecological
symptoms in women with endometriosis and do not necessarily reflect bowel
involvement. AIM: The aim of this study was to evaluate how many patients with endometriosis
have concomitant irritable bowel syndrome (IBS) and/or constipation according to
the Rome III criteria. Furthermore, the value of an additional
gastroenterological consultation with therapeutic advice was evaluated.
METHOD: Patients with proven endometriosis were included in a prospective,
single-centre study. A questionnaire was undertaken regarding IBS and chronic
constipation. Patients with symptoms consistent with the Rome III criteria for
IBS were referred to our gastroenterological outpatient clinic.
RESULTS: In total 101 patients were included. Endometriosis was diagnosed
surgically in 97% and visually in the vagina in 3%. Fifteen per cent of the
patients with endometriosis also had IBS and 14% of the patients with
endometriosis had functional constipation without IBS. Of the 22 patients
finally presenting to the gastroenterologist, five had a significant stenotic
rectosigmoid lesion and were treated surgically. The remaining 17 patients were
treated conservatively. Defecation symptoms improved in 86% and pain was reduced
in 64%.
CONCLUSION: In patients with endometriosis, 29% also had IBS or constipation.
Referral to a gastroenterologist resulted in improvement of defaecation in 86%,
and 64% reported a reduction in the degree of pain. BACKGROUND: Advances in understanding the epidemiology of endometriosis have
lagged behind other diseases because of methodological problems related to
disease definition and control selection.
AIM: To identify possible risk factors associated with the development of
endometriosis among a sample of Egyptian women.
MATERIALS AND METHODS: A case-control study was conducted in the University
Maternity Hospital and some private hospitals in Alexandria. The sample included
110 cases recently diagnosed with endometriosis and 220 hospital-based,
age-matched controls.
RESULTS: Using the logistic regression analysis, nulligravidae were four times
more likely to develop endometriosis than gravid women [adjusted odds ratio
(AOR)=4.0, 95% confidence interval (CI) (2.2-7.6)]. Short cycles were associated
with approximately six times increase in risk of endometriosis [AOR=6.1, 95% CI
(2.9-12.8)]. Women with irregular cycles were three times more likely to develop
endometriosis than women with regular cycles [AOR=3.5, 95% CI (1.89-6.71)].
Similarly, women with a history of irritable bowel syndrome were twice as likely
to develop endometriosis [AOR=1.9, 95% CI (1.03-3.87)]. Women who had one or
more relatives with endometriosis were 1.2 times more likely to develop
endometriosis [AOR=1.2, 95% CI (1.19-1.43)].
CONCLUSION AND RECOMMENDATIONS: Nulliparous and women reporting short and
irregular cycles were at a significantly increased risk of developing
endometriosis. A weak association between reported family history of
endometriosis and history of irritable bowel syndrome and the development of
endometriosis was also observed. Designing and implementing health education
programs about endometriosis and its related risk factors should be a priority
to ensure early diagnosis of the disease. INTRODUCTION: Intestinal endometriosis is often an infrequently considered
diagnosis in female of childbearing age by general surgeon. There is a delay in
diagnosis because of constellation of symptoms and lack of specific diagnostic
modalities. Patients suffer from intestinal endometriosis for many years before
they are diagnosed. Often, such patients are labelled with irritable bowel
syndrome. Intestinal endometriosis has a diagnostic time delay of 8-11 years due
to its non-specific clinical features and multi-system involvement.
PRESENTATION OF CASE: Our patient was a 32 years old Caucasian female who was
referred to us with features of intestinal obstruction. Despite repeated
clinical assessments and use of different diagnostic modalities the diagnosis
was still inconclusive even after 21 days of her first presentation to primary
care physician. She had an exploratory laparotomy, sigmoid colectomy, and
Hartmann's procedure with a temporary colostomy with us. Histopathology
confirmed endometriosis and also showed melanosis coli. She was referred to the
gynaecological team for review and follow up.
DISCUSSION: Intestinal endometriosis should be considered as a differential
diagnosis in female patients of childbearing age group presenting with
non-specific gastrointestinal signs and symptoms. Our patient manifested
intestinal endometriosis and melanosis coli on histopathology suggesting
symptoms of long duration.
CONCLUSION: Bowel endometriosis is a less considered and often ignored
differential diagnosis in acute and chronic abdomen. This condition has
considerable effect on patient's health both physically and psychologically. STUDY OBJECTIVE: Adult women with endometriosis are often diagnosed with
comorbid pain, mood, and autoimmune conditions. This study aims to describe the
occurrence of pain syndromes, mood conditions, and asthma in adolescents and
young women with endometriosis evaluated at our medical center.
DESIGN: Retrospective review of medical records.
SETTING: Department of Obstetrics and Gynecology at a tertiary referral center.
PARTICIPANTS: 138 adolescents/young women who were less than age 24 years at the
time of their initial visit at our medical center, and whose surgical diagnosis
of endometriosis was made at our institution or by outside institutions by the
age of 21.
INTERVENTIONS: None.
MAIN OUTCOME MEASURES: Prevalence of comorbid pain syndromes (defined as
interstitial cystitis, irritable bowel syndrome, chronic headaches, chronic low
back pain, vulvodynia, fibromyalgia, temporomandibular joint disease, and
chronic fatigue syndrome), mood conditions (defined as depression and anxiety),
and asthma.
RESULTS: Comorbid pain syndromes were found in 77 (56%) women, mood conditions
in 66 (48%) women, and asthma in 31 (26%) women. Comparing endometriosis
patients with and without comorbid pain syndromes, no differences were found in
age at time of diagnosis, endometriosis symptoms, and endometriosis stage.
Patients with comorbid pain syndromes were more likely to report mood conditions
(62% vs 30% respectively, P < .001) and smoking (31% vs 10% respectively, P =
.003), underwent more surgeries for endometriosis (median of 2 [range, 1-7] vs 1
[range, 1-5], P < .005), and were more likely to undergo appendectomy or
cholecystectomy (30% vs 13%, P = .02).
CONCLUSIONS: Comorbid pain syndromes, mood conditions and asthma are common in
adolescents and young women with endometriosis. |
What is evaluated using the EORTC QLQ – INFO25 questionnaire? | The European Organisation for Research and Treatment of Cancer Quality of Life Group information questionnaire (EORTC QLQ-INFO 25) evaluates the level of information patients have received in different areas of their disease, treatment and care, and evaluates qualitative aspects together with satisfaction with information. | Information is one of the main interventions given to cancer patients. Important
research into information disclosure has been conducted and major advances have
been made. We present the main theoretical models used to understand the
information field and describe the current situation regarding the principal
factors related to information: patients' needs, coping strategies, illness
representations, cross-cultural differences, the role of the family, and
strategies to enhance information giving, such as professional training and
patient-targeted interventions. We highlight the need to assess patients'
characteristics and desires through questionnaires and interviews and present
the European Organisation for Research and Treatment of Cancer Quality of Life
Group information questionnaire (EORTC QLQ-INFO 25). This instrument evaluates
the level of information patients have received in different areas of their
disease, treatment and care, and evaluates qualitative aspects. Finally, we
describe the key areas of the information field and discuss how these areas
could change in the future. INTRODUCTION: The EORTC QLQ-INFO25 evaluates the information received by cancer
patients. This study assesses the psychometric properties of the QLQ-INFO25 when
applied to a sample of Spanish patients.
MATERIALS AND METHODS: A total of 169 patients with different cancers and stages
of disease completed the EORTC QLQINFO25, the EORTC QLQ-C30 and the information
scales of the inpatient satisfaction module EORTC IN-PATSAT32 on two occasions
during the patients' treatment and follow- up period. Psychometric evaluation of
the structure, reliability, validity and responsiveness to changes was
conducted. Patient acceptability was assessed with a debriefing questionnaire.
RESULTS: Multi-trait scaling confirmed the 4 multi-item scales (information
about disease, medical tests, treatment and other services) and eight single
items. All items met the standards for convergent validity and all except one
met the standards of item discrimit validity. Internal consistency for all
scales (α>0.70) and the whole questionnaire (α>0.90) was adequate in the three
measurements, except information about the disease (0.67) and other services
(0.68) in the first measurement, as was test-retest reliability (intraclass
correlations >0.70). Correlations with related areas of IN-PATSAT32 (r>0.40)
supported convergent validity. Divergent validity was confirmed through low
correlations with EORTC QLQ-C30 scales (r<0.30). The EORTC QLQ-INFO-25
discriminated among groups based on gender, age, education, levels of anxiety
and depression, treatment line, wish for information and satisfaction. One scale
and an item showed changes over time.
CONCLUSIONS: The EORTC QLQ-INFO 25 is a reliable and valid instrument when
applied to a sample of Spanish cancer patients. These results are in line with
those of the EORTC validation study. OBJECTIVE: Informational needs among cancer patients are similar, but the degree
of information disclosure in different cultural areas varies. In this paper, we
present the results of a cross-cultural study on information received.
METHODS: The EORTC information questionnaire, EORTC QLQ-INFO25, was administered
during the treatment process. This questionnaire evaluates the information that
patients report they have received. Cross-cultural differences in information
have been evaluated using statistical tests such as Kruskall-Wallis and
multivariate models with covariates to account for differences in clinical and
demographic characteristics across areas.
RESULTS: Four hundred and fifty-one patients from three cultural areas,
North-Middle Europe, South Europe, and Taiwan, were included in the study.
Significant differences among the three cultural areas appeared in eight
QLQ-INFO25 dimensions: information about the disease; medical tests; places of
care; written information; information on CD/tape/video; satisfaction; wish for
more information; and information helpfulness. North-Middle Europe patients
received more written information (mean = 67.2 (North) and 33.8 (South)) and
South Europe patients received more information on different places of care
(mean = 24.7 (North) and 35.0 (South)). Patients from North-Middle Europe and
South Europe received more information than patients from Taiwan about the
disease (mean = 57.9, 60.6, and 47.1, respectively) and medical tests (70.9,
70.4, and 54.5), showed more satisfaction (64.8, 70.2, and 35.0), and considered
the information more helpful (71.9, 73.9, and 50.4). These results were
confirmed when adjusting for age, education, and disease stage.
CONCLUSION: There are cross-cultural differences in information received. Some
of these differences are based on the characteristics of each culture. BACKGROUND: Information is vital to cancer patients. Physician-patient
communication in oncology presents specific challenges. The aim of this study
was to evaluate self-reported information of cancer patients in ambulatory care
at a comprehensive cancer centre and examine its possible association with
patients' demographic and clinical characteristics.
PATIENTS AND METHODS: This study included adult patients with solid tumours
undergoing chemotherapy at the Institute Jules Bordet's Day Hospital over a
ten-day period. EORTC QLQ-C30 and QLQ-INFO25 questionnaires were administered.
Demographic and clinical data were collected. Descriptive and inferential
statistics were used.
RESULTS: 101 (99%) fully completed the questionnaires. They were mostly Belgian
(74.3%), female (78.2%), with a mean age of 56.9 ± 12.8 years. The most frequent
tumour was breast cancer (58.4%). Patients were well-informed about the disease
and treatments, but presented unmet information domains. The Jules Bordet
patients desired more information on treatment side effects, long-term outcome,
nutrition, and recurrence symptoms. Patients on clinical trials reported having
received less information about their disease and less written information than
patients outside clinical trials. Higher information levels were associated with
higher quality of life (QoL) scores and higher patient satisfaction.
CONCLUSION: Patients were satisfied with the information they received and this
correlated with higher QoL, but they still expressed unmet information wishes.
Additional studies are required to investigate the quality of the information
received by patients enrolled in clinical trials. INTRODUCTION: Developing a tool for measuring patient's needs is a vital step in
the process of cancer treatment and research. In recent years, the European
Organization for Research and Treatment of Cancer (EORTC) made a questionnaire
to measure cancer patients' received information. Since validity and reliability
of any instrument should be evaluated in the new environment and culture, the
aim of this study was to assess the validity and reliability of the EORTC
QLQ-INFO25 in Iranian cancer patients.
MATERIALS AND METHODS: One hundred seventy-three patients with different stages
of cancer filled questionnaire EORTC QLQ-INFO25, EORTC QLQ-C30, and EORTC
IN-PATSAT32. Twenty-five patients answered the questionnaire twice at an
interval of 2 weeks. Reliability and validity of the questionnaire was measured
by Cronbach's alpha, interclass correlation, test retest, inter-rater agreement
(IRA), and exploratory factorial analyses.
RESULTS: Using a conservative approach, the IRA for the overall relevancy and
clarity of the tool was 87/86% and 83.33%, respectively. Overall appropriateness
and clarity were 94.13 and 91.87%, respectively. Overall integrity of the
instrument was determined to be 85%. Cronbach's alpha coefficients for all
domains and total inventory were top 70 and 90%, respectively. Interclass
correlation index ranges between 0.708 and 0.965. Exploratory factorial analyses
demonstrate six fields suitable for instrument. Correlation between areas of the
questionnaires EORTC QLQ-INFO25 and EORTC in-Patsat32 represents the convergent
validity of the questionnaire. Also, results show a standard divergent validity
in all domains of the questionnaire (Rho <0.3). Low correlation between the
areas of the questionnaires EORTC QLQ-INFO25 and EORTC QLQ-C30 (<0.3)
demonstrates the divergence validity of the questionnaire.
CONCLUSION: The results showed that Persian version of the questionnaire EORTC
QLQ-INFO25 is a reliable and valid instrument for measuring the perception of
information in cancer patients. |
Does BNP increase after intensive exercise in athletes? | BNP and NTproBNP increase early after exercise in healthy athletes performing different types of sports. It is unknown the reason of this increase. The transient increases in BNP, NT-pro-BNP and troponin T are more likely to reflect myocardial stunning than cardiomyocyte damage. | BACKGROUND: Now that marathon racing is growing in popularity, many thousands of
enthusiastic athletes are participating in various ultramarathons all over the
world each year. However, it remains controversial whether such a sport
contributes to the promotion of health. The occurrence of transient cardiac
dysfunction and irreversible myocardial injury has been reported in association
with such exercise in healthy individuals. Brain natriuretic peptide (BNP) is a
cardiac hormone, as is atrial natriuretic peptide (ANP), and its measurement has
been widely used for clinical evaluation of cardiac dysfunction. However, little
is known about the response of plasma BNP to prolonged strenuous exercise. We
hypothesized that confirmation of minimal cardiac dysfunction or myocardial
injury may be made by measurements of plasma BNP.
METHODS: Levels of plasma ANP, BNP, catecholamines, blood lactate, and serum
cardiac troponin T (cTnT) were determined before and after a 100-km
ultramarathon in 10 healthy men to examine the effects of the exercise on levels
of ANP and BNP and correlations between the natriuretic peptides and cTnT as a
marker for myocardial damage.
RESULTS: Whereas all variables significantly increased after the race, increased
levels of ANP and BNP were most strongly correlated with increases in cTnT
levels. The cTnT level after the race was greater than the upper reference limit
in 9 of 10 men.
CONCLUSIONS: Such exercise significantly increased ANP and BNP levels in healthy
men, and the increases could be partially attributed to myocardial damage during
the race. The echocardiographic measures and plasma concentrations of either atrial
natriuretic peptide (ANP) or brain natriuretic peptide (BNP) were compared in
elite judo practitioners (static athletes), elite marathon runners (dynamic
athletes) and healthy controls to investigate the relationship between the
different types of left ventricular (LV) hypertrophy and plasma concentrations
of natriuretic peptides in athletes. The LV mass and LV wall thickness of
marathon runners and judo practitioners were significantly greater than those of
controls. The LV end-diastolic dimension index was significantly larger in the
marathon group, but smaller in the judo group. The left atrial dimension (LAD)
index was significantly larger only in marathon runners. Plasma BNP
concentrations were higher in both the judo and marathon groups than in
controls, and positively correlated with LV mass as well as with deceleration
time. Plasma ANP concentrations were significantly higher in marathon runners
than in the controls and judo groups, and positively correlated with the LAD
index, but negatively correlated with ejection fraction. Multivariate analyses
showed that the type of athlete and LAD index were independent predictors of
plasma BNP and ANP concentrations, respectively. Thus, there is an intimate link
between plasma concentrations of natriuretic peptides and cardiac morphology in
different types of athletes. For a further depiction of exercise-induced cardiac dysfunction, N-terminal
pro-brain natriuretic peptide (NT-pro-BNP) and cardiac troponin T (cTnT) were
measured in recreational cyclists (n = 29) during the Otztal Radmarathon 2004.
In all subjects, NT-pro-BNP significantly increased from 28 +/- 21 to 278 +/-
152 ng/L immediately after the race (p <0.001), decreased again on the following
day, and returned to baseline values 1 week later. The mean percentage increase
in NT-pro-BNP was 1,128 +/- 803%. CTnT, negative in all subjects before the
race, increased transiently in 13 athletes (45%), with levels ranging from 0.043
to 0.224 mug/L in 8 of them (28%). One day after competition, cTnT had
normalized in all athletes. Because of the typical release of kinetics, the
deflection of NT-pro-BNP is considered to be the adequate volume regulatory
response of a hemodynamically stressed heart to prolonged strenuous exercise.
The observed kinetics of cTnT substantiate a release from the free cytoplasmatic
pool due to the half-life of cytosolic cTnT. In healthy cyclists, transient
increases in NT-pro-BNP and cTnT are more likely to reflect cardiac fatigue than
injury. BACKGROUND: Although elevated resting brain natriuretic peptide (BNP)
concentrations reflect heart disease, the meaning of exercise-induced increases
is poorly understood and has been examined in small groups only. Therefore, the
present study aimed to examine the increase in N-terminal pro-brain natriuretic
peptide (NT-proBNP) and relations to cardiac troponin I and T (cTnI, cTnT)
elevations after prolonged strenuous exercise in a large cohort of athletes.
METHODS: We examined exercise-induced changes in NT-proBNP, cTnI, and cTnT in
105 obviously healthy endurance athletes (40 +/- 8 years) before and after
prolonged strenuous exercise. Blood samples were taken before, 15 minutes, and 3
hours after a marathon (n = 46), a 100-km run (n = 14), and a mountain bike
marathon (n = 45).
RESULTS: Eighty-one of 105 athletes exceeded the upper reference limit of
NT-proBNP (males/females 88:153 ng/L) after exercise. NT-proBNP increased in all
3 events (P < .001) with the highest increase in the 100-km runners (median
increase 200 ng/L; 25th/75th percentile 115/770 ng/L), which differed from the
increase in the marathon (97 ng/L; 36/254 ng/L) or the mountain bike marathon
(78 ng/L; 37/196 ng/L) (P < .01). Cardiac troponin I exceeded 0.04 microg/L in
74%; cTnT exceeded 0.01 microg/L in 47% of athletes after exercise. NT-proBNP
was not related to exercise-induced increases in cTnI or cTnT, but correlated
with exercise time (r = 0.55, P < .001).
CONCLUSIONS: Increases in NT-proBNP can be found in a major part of obviously
healthy athletes after prolonged strenuous exercise. The release of BNP during
and after exercise may not result from myocardial damage but may have
cytoprotective and growth-regulating effects. The different nature of
exercise-induced increases in BNP and cardiac troponins has to be elucidated in
the future. AIM: Brain natriuretic peptide (BNP) is a cardioactive molecule produced in the
myocardium. BNP is a sensitive marker of cardiac failure and its measurement in
blood could be useful to the diagnosis and the treatment of this disease.
Sporting activities, especially endurance ones, can induce cardiac problems,
owing to the high workload for the myocardium during long and ultralong heavy
effort. There are 2 papers describing the behavior of BNP in endurance events.
BNP was elevated in marathoners, immediately after the race and also after 4 h.
We studied the behavior of BNP in the triathlon, which is a complex sport
characterized by 3 different activities (swimming, cycling, running).
METHODS: We recruited 49 athletes, all males, except for 4 females; 2 athletes
did not finish the race and were not included in the statistical analysis in 2
different competitions. In these subjects we measured BNP using an immunological
method before and after a triathlon.
RESULTS: No statistical significance between BNP values, before and after the
triathlon, was found.
CONCLUSIONS: We found no significant differences between pre- and
postcompetition BNP values. Moreover, the range of values in both the blood
drawings are similar of those of the general population, representing the
biological variability of the analyte. The values in regularly trained
athletes,, are not different from the general population and BNP is not modified
by a triathlon, a typical endurance sport performance. We can underline that BNP
increases in plasma are induced by heavy pathologies and are not influenced by
physical activities, even strenuous ones. The aim of this study was to examine cardiac dysfunction following
ultra-endurance exercise in male athletes. Fourteen athletes (mean+/-SD, age
39+/-8 years) were evaluated before and after the European Championship in
Triathlon 2003 using echocardiogram (ECG), cardiac markers [cardiac troponin T
(cTnT) and pro-brain natriuretic peptide (pro-BNP)] and echocardiography.
Conventional echocardiography techniques and new Doppler tissue imaging (DTI)
modalities were applied before and immediately after the competition. Blood
samples were drawn 1 week before, immediately after and 12-24 h
post-competition. CTnT significantly increased immediately, but decreased to
within normal limits 12-24 h post-competition. Pro-BNP was significantly
increased immediately post-race (27+/-21 vs 7+/-2 pmol/L pre-race, P < or =
0.007), which 12-24 h later, decreased to 19+/-14 pmol/L (P = 0.07 vs pre-race).
During echocardiography, no significant differences were found in regional or
global systolic parameters. Early diastolic peak flow velocity (9+/-2, P = 0.04)
and E/A ratio (2+/-1, P = 0.004) were increased pre-race and decreased
significantly toward normal values. In one athlete, cTnT levels increased
significantly and systolic velocities decreased, thus suggesting reversible
cardiac fatigue. When using cardiac markers and echocardiographic findings, a
triathlon was found to have no significant negative effects on left ventricular
function or myocardial tissue in male athletes. PURPOSE: Transient cardiac ventricular dysfunction or sudden cardiac deaths have
been reported for male athletes participating in marathon racing. Less is known
about the myocardial response in females. We examined natriuretic peptides and
cardiac troponins in female athletes after a marathon.
METHODS: At the 31st real,- Berlin Marathon plasma levels of NT-pro-BNP, BNP,
cTnI and cTnT were measured in 15 women (age 35+/-6 years; finishing times
between 3:22 h and 5:21 h) at four different time points (before, immediately
after, day one and day three).
RESULTS: An increase in [NT-pro-BNP] was observed immediately after the marathon
(median [NT-pro-BNP] before: 39.6 pg ml(-1), after: 138.6 pg ml(-1), p=0.003)
with a further increase on day one. [BNP] did not increase immediately after the
marathon but increased on day one (median [BNP] before: 15 pg ml(-1), day one:
27.35 pg ml(-1), p=0.006). On day three, [NT-pro-BNP] and [BNP] returned to
initial values. [cTnI] was under the detection limit prior to the marathon in
all runners. [cTnT] was under the detection limit before the marathon except in
one runner who presented a concentration of 0.03 ng ml(-1). Cardiac troponins
(median [cTnl] after: 0.098 ng ml(-1), p=0.028; median [cTnT] after: 0.032 ng
ml(-1), p=0.012) increased immediately after the marathon and returned to
initial values on day one [cTnT] and three [cTnI].
DISCUSSION: Parameters representing cardiac stress increased in females after a
marathon. Different kinetics of natriuretic peptides BNP and NT-pro-BNP
post-marathon could be due to their different half-lives and dependence on renal
function. The increase of cTnI and cTnT may result from minor myocardial
lesions. PURPOSES: To comprehensively investigate the cardiovascular consequences of a
160-km ultramarathon using traditional echocardiography, speckle tracking
imaging, cardiac biomarkers, and heart rate variability (HRV) and to examine the
relationship between the changes in these variables.
METHODS: We examined athletes before an ultramarathon and reassessed all
finishers immediately after the race. Left ventricular (LV) systolic (ejection
fraction [EF], systolic blood pressure/end-systolic volume [SBP/ESV] ratio) and
diastolic (ratio of early [E] to late [A], filling E:A) measurements were
assessed using traditional echocardiography, whereas myocardial peak strain and
strain rate were analyzed using speckle tracking. Cardiac biomarkers measured
were cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptide
(NT-pro-BNP). HRV indices were assessed using standard frequency and time domain
measures.
RESULTS: Twenty-five athletes successfully completed the race (25.5 +/- 3.2 h).
Significant pre- to postrace changes in EF (66.8 +/- 3.8 to 61.2 +/- 4.0 %, P <
0.05) and E:A ratio (1.62 +/- 0.37 to 1.35 +/- 0.33, P < 0.05) were reported.
Peak strain was significantly decreased in all planes, with the largest
reduction occurring circumferentially. NT-pro-BNP concentrations increased
significantly (28 +/- 17.1 vs 795 +/- 823 ng x L, P < 0.05), whereas postrace
cTnT were elevated in just five athletes (20%). No significant alterations in
HRV were noted postrace. Reductions in LV function were not significantly
associated with changes in cardiac biomarkers and/or HRV.
CONCLUSIONS: Although the stress of an ultramarathon resulted in a mild
reduction in LV function and biomarker release, the mechanisms behind such
consequences remain unknown. It is likely that factors other than myocardial
damage or strong vagal reactivation contributed to postexercise decreases in LV
function after an ultramarathon. |
What is the association of estrogen replacement therapy and intracranial meningioma risk? | The association between hormone replacement therapy and meningioma risk is controversial. Increased risk of meningioma was demonstrated in estrogen-only hormonal replacement therapy. However, other studies did not find an association between hormonal replacement therapy and meningioma risk. | Meningiomas are slow-growing benign brain tumors. The etiology of meningioma is
largely unknown, and exposure to high-dose ionizing radiation and coexistence
with certain rare genetic conditions explain only a small fraction of the
incidence of the disease. The evidence that implicates gender-specific hormones
in the pathogenesis of meningioma emanates from data showing increased growth of
meningiomas during pregcy and change in size during menses. Observational
data have identified the menopause and oophorectomy as conferring protection
against the risk of developing meningiomas, while adiposity is positively
associated with the disease. These tumors are also positively associated with
breast cancer, although they express a different gonadal steroid receptor
repertoire. About 70% of meningiomas express progesterone receptors, while fewer
than 31% express estrogen receptors. These observations suggest that
progesterone influences tumor growth. A progesterone antagonist such as
mifepristone therefore may inhibit tumor growth. The use of hormone replacement
therapy in symptomatic postmenopausal women either with previously treated
disease or with dormant tumors is discussed, but remains controversial. Meningiomas occur more commonly in females. The coincidence between meningioma
and breast cancer and case reports of tumor growth during pregcy support a
hormonal hypothesis. A case control study was conducted to investigate this.
Female subjects treated between 1987 and 1992 were identified from 3 hospitals
in the Chicago area. Female spouses of male back pain patients were recruited as
controls. A self-administered mail questionnaire focused on exogenous,
endogenous and other hormonal factors, personal and family medical history as
well as radiation exposures. Odds ratios and 95% confidence intervals were
estimated using crude, stratified and multivariable logistic models including
219 cases and 260 controls. Participation rates were 86% among cases and 75%
among controls. An increased odds ratio (OR) was observed comparing African
Americans to Caucasians [OR = 2.4, 95% confidence interval (CI) = 1.0-6.1]. A
protective effect was observed for pregcy, which increased with number and
age at first pregcy. The odds ratio for 3 or more pregcies compared to
none was 0.3 (95% CI = 0.2-0.6). Age at menarche or total period of hormonal
activity was not protective. Ever smokers showed a decreased odds ratio for
meningioma (OR = 0.6, 95% CI = 0.4-0.9). The increased odds ratios with African
Americans was retained in post-menopausal women, while the protective odds
ratios for pregcy, smoking and oral contraceptives (OCs) became stronger in
pre-menopausal women. The pattern by duration and timing of use does not suggest
an etiologic role for OCs or hormone replacement therapy. These data add to the
evidence that factors known to influence endogenous hormones (pregcy and
indirectly smoking) may have protective effects for meningiomas primarily in
premenopausal women. The decision to commence or continue use of hormone replacement therapy or oral
contraceptives in women presumed or known to be diagnosed with intracranial
meningioma is a common clinical question in neurosurgery. A review of the
English-language literature was undertaken to examine the association between
the use of exogenous hormones and meningioma risk. Seven publications were
identified, 6 of which met criteria for inclusion. No randomized clinical trial
data were available, hence, results were collected from 2 population-based
case-control studies, 2 hospital-based case-control studies, 1 nested
case-control study drawn from a large national cohort, and 1 retrospective
cohort study. At present, there is no statistical evidence of an increased risk
of meningioma among users of oral contraceptives. Although not definitive,
available data suggest an association between the use of hormone replacement
therapy and increased meningioma risk. Further evaluation of exogenous hormone
use in women with meningioma is needed with particular attention to
stratification by hormone (ie, estrogen and/or progesterone) composition,
duration of and age at use as well as tumor receptor subtype. We examined the relation between the use of hormone replacement therapy (HRT)
and the incidence of central nervous system (CNS) tumours in a large prospective
study of 1,147,894 postmenopausal women. Women were aged 56.6 years on average
at entry, and HRT use was recorded at recruitment and updated, where possible,
about 3 years later. During a mean follow-up of 5.3 years per woman, 1,266 CNS
tumours were diagnosed, including 557 gliomas, 311 meningiomas and 117 acoustic
neuromas. Compared with never users of HRT, the relative risks (RRs) for all
incident CNS tumours, gliomas, meningiomas and acoustic neuromas in current
users of HRT were 1.20 (95% CI: 1.05-1.36), 1.09 (95% CI: 0.89-1.32), 1.34 (95%
CI: 1.03-1.75) and 1.58 (95% CI: 1.02-2.45), respectively, and there was no
significant difference in the relative risks by tumour type (heterogeneity p =
0.2). In past users of HRT the relative risk was 1.07 (95% CI: 0.93-1.24) for
all CNS tumours. Among current users of HRT, there was significant heterogeneity
by the type of HRT with the users of oestrogen-only HRT at higher risk of all
CNS tumours than users of oestrogen-progestagen HRT (RR = 1.42, 95% CI:
1.21-1.67 versus RR = 0.97, 95% CI: 0.82-1.16) (heterogeneity p < 0.001). Among
current users of oestrogen-only and oestrogen-progestagen HRT, there was no
significant heterogeneity by duration of use, hormonal constituent or mode of
administration of HRT. BACKGROUND: Previous studies on association of exogenous female sex hormones and
risk for meningioma have yielded conflicting results. The aim of this study was
to evaluate the potential relation between prior use of menopausal hormone
therapy or oral contraception and risk of meningioma.
METHODS: This population-based case-control study was conducted during years
2000-2002 in Finland. All women aged 20-69 years with meningioma diagnosis were
identified from five university hospitals, and frequency-matched controls were
randomly chosen from population register. A total of 264 cases and 505 controls
were interviewed on their use of menopausal hormone therapy, oral and other
contraception, fertility treatment, treatment for gynecological problems, age at
menarche, and number of children. We also analyzed separately tumors expressing
progesterone or estrogen receptors. Of the successfully stained tumor specimens,
86.3% were positive for progesterone receptor and 50% for estrogen receptor.
RESULTS: Postmenopausal hormonal treatment, use of contraceptives, or fertility
treatment did not influence the risk of meningioma. In further analysis by
hormone receptor status, there was some indication for an increased risk of
progesterone receptor-positive meningiomas associated with oral contraceptive
use (OR 1.39, 95% confidence interval 0.92-2.10) and other hormonal
contraception (OR 1.50, 95% CI 0.95-2.36).
CONCLUSIONS: Overall, we found little indication that reproductive factors or
use of exogenous sex hormones affect meningioma risk. A retrospective study including more than 350,000 women, about 1400 of whom had
developed meningioma, showed that the risk of meningioma was about twice as high
in users of postmenopausal hormone replacement therapy as in non-users. Hormone
replacement therapy should be discontinued if meningioma is diagnosed. The authors conducted a nationwide cohort study to evaluate the association
between postmenopausal hormone therapy and meningioma incidence in Finland. All
women who had used hormone therapy at least for 6 months at the age of 50 years
or older during 1994-2009 were included. Women who had used postmenopausal
hormone therapy were identified from the medical reimbursement register of the
Social Insurance Institution (131,480 estradiol users and 131,248
estradiol-progestin users), and meningioma cases were identified from the
Finnish Cancer Registry. During the average 9 years of follow-up, 289 estradiol
users and 196 estradiol-progestin users were diagnosed with meningioma. Ever use
of estradiol-only therapy was associated with an increased risk of meningioma
(standardized incidence ratio = 1.29, 95% confidence interval: 1.15, 1.44).
Among women who had been using estradiol-only therapy for at least 3 years, the
incidence of meningioma was 1.40-fold higher (95% confidence interval: 1.18,
1.64; P < 0.001) than in the background population. In contrast, this risk was
not increased in users of combination therapy (standardized incidence ratio =
0.93, 95% confidence interval: 0.80, 1.06). There was no difference in risk
between continuous and sequential use of hormone therapy. Estradiol-only therapy
was accompanied with a slightly increased risk of meningioma. OBJECT: The 2-fold higher incidence of meningioma in women compared with men has
long suggested a role for hormonally mediated risk factors, but specific
mechanisms remain elusive.
METHODS: The study included data obtained in 1127 women 29-79 years of age with
intracranial meningioma diagnosed among residents of Connecticut, Massachusetts,
North Carolina, the San Francisco Bay Area, and 8 Texas counties between May 1,
2006, and October 6, 2011, and data obtained in 1092 control individuals who
were frequency matched for age group and geography with meningioma patients.
RESULTS: No association was observed for age at menarche, age at menopause, or
parity and meningioma risk. Women who reported breastfeeding for at least 6
months were at reduced risk of meningioma (OR 0.78, 95% CI 0.63-0.96). A
significant positive association existed between meningioma risk and increased
body mass index (p < 0.01) while a significant negative association existed
between meningioma risk and current smoking (p < 0.01). Among premenopausal
women, current use of oral contraceptives was associated with an increased risk
of meningiomas (OR 1.8, 95% CI 1.1-2.9), while current use of hormone
replacement therapy among postmenopausal women was not associated with a
significant elevation in risk (OR 1.1, 95% CI 0.74-1.67). There was no
association between use of fertility medications and meningioma risk.
CONCLUSIONS: The authors' study confirms associations for body mass index,
breastfeeding, and cigarette smoking but provides little evidence for
associations of reproductive and menstrual factors with meningioma risk. The
relationship between current use of exogenous hormones and meningioma remains
unclear, limited by the small numbers of patients currently on oral hormone
medications and a lack of hormone receptor data for meningioma tumors. AIM: Several studies indicate that use of hormone replacement therapy (HRT) is
associated with an increased risk of intracranial meningioma, while associations
between HRT use and risk of other brain tumors have been less explored. We
investigated the influence of HRT use on the risk of glioma in a nationwide
setting.
METHODS: Using population-based registries we conducted a case-control study
nested in the Danish female population. We identified all women aged 55-84 years
with a first diagnosis of histologically verified brain glioma during 2000-2009.
Using risk-set sampling, each case was matched on birth year to eight population
controls. Ever use of HRT was defined as ≥2 HRT prescriptions and categorized
according to type (oestrogens only, combined oestrogen-progestagen and
progestagen only) and duration of use (<1, ≥1 to <5, ≥5 to <10, and ≥10 years).
We used conditional logistic regression to compute odds ratios (ORs), with 95%
confidence intervals (CIs), for glioma associated with HRT use, adjusting for
potential confounders.
RESULTS: We identified 658 cases and 4350 controls. Ever use of HRT was
associated with an OR of 0.9 (95% CI: 0.8-1.1) for glioma. For long-term use
(≥10 years) we found ORs of 1.1 (95% CI: 0.7-1.7) for HRT overall, 1.6 (95% CI:
0.9-2.6) for oestrogen only, 0.8 (0.4-1.6) for combined oestrogen-progestagen,
and 2.2 (0.9-5.5) for progestagen. Tests for trends were statistically
non-significant in all strata.
CONCLUSION: Use of HRT overall was not associated with an increased risk of
glioma. However, our findings indicate that prolonged use of oestrogen only or
progestagen may be associated with an increased risk of glioma. Female sex hormones are thought to affect women's risk of developing central
nervous system (CNS) tumors. Some have reported an increased risk in users of
menopausal hormone therapy (HT) but evidence is limited. In the UK General
Practice Research Database we compared prospectively collected information on HT
prescriptions in women aged 50-79 years with CNS tumors diagnosed in 1987-2011
with that in matched controls (four per case). Relative risks (RRs) in relation
to prescribed HT were calculated overall and by CNS tumor subtype. Statistical
tests are two-sided. For all CNS tumors (n = 3,500), glioma (n = 689),
meningioma (n = 1,197), acoustic neuroma (n = 439), and pituitary tumors (n =
273) adjusted RRs for women prescribed HT versus not were, respectively, 1.21
(95% confidence intervals (CI) = 1.10-1.32, p < 0.0001), 1.14 (0.93-1.40, p =
0.2), 1.30 (1.11-1.51, p = 0.001), 1.37 (1.06-1.75, p = 0.01), and 1.35
(0.99-1.85, p = 0.06). There was no significant difference in risk by tumor
subtype (p(heterogeneity) = 0.6). A meta-analysis was conducted, combining our
results with those from other published studies with prospectively collected
exposure information. The meta-analyses yielded significantly increased risks
for all CNS tumors, glioma and meningioma in users of estrogen-only [1.35
(1.22-1.49), 1.23 (1.06-1.42) and 1.31 (1.20-1.43), respectively] but not
estrogen-progestin HT [1.09 (0.99-1.19), 0.92 (0.78-1.08) and 1.05 (0.95-1.16),
respectively]; these differences were statistically significant (p < 0.005 for
each tumor type). There was no significant difference between glioma and
meningioma risk in users of estrogen-only HT. The totality of the available
evidence suggests an increased risk of all CNS tumors (and of glioma and
meningioma separately) in users of estrogen-only HT. Absolute excess risk (2 per
10,000 users over 5 years) is small. |
Are there web based self management strategies for chronic pain ? | Results suggest the potential value of self-management for chronic pain patients and the potential acceptability of web-based delivery of intervention content. | BACKGROUND: Internet-based interventions are increasingly used to support
self-management of individuals with chronic illnesses. Web-based interventions
may also be effective in enhancing self-management for individuals with chronic
pain, but little is known about long-term effects. Research on Web-based
interventions to support self-management following participation in pain
management programs is limited.
OBJECTIVE: The aim is to examine the long-term effects of a 4-week
smartphone-intervention with diaries and therapist-written feedback following an
inpatient chronic pain rehabilitation program, previously found to be effective
at short-term and 5-month follow-ups.
METHODS: 140 women with chronic widespread pain, participating in a 4-week
inpatient rehabilitation program, were randomized into two groups: with or
without a smartphone intervention after the rehabilitation. The smartphone
intervention consisted of one face-to-face individual session and 4 weeks of
written communication via a smartphone, consisting of three diaries daily to
elicit pain-related thoughts, feelings, and activities, as well as daily
personalized written feedback based on cognitive behavioral principles from a
therapist. Both groups were given access to an informational website to promote
constructive self-management. Outcomes were measured with self-reported
paper-and-pencil format questionnaires with catastrophizing as the primary
outcome measure. Secondary outcomes included daily functioning and symptom
levels, acceptance of pain, and emotional distress.
RESULTS: By the 11-month follow-up, the favorable between-group differences
previously reported post-intervention and at 5-month follow-up on
catastrophizing, acceptance, functioning, and symptom level were no longer
evident (P>.10). However, there was more improvement in catastrophizing scores
during the follow-up period in the intervention group (M=-2.36, SD 8.41)
compared to the control group (M=.40, SD 7.20), P=.045. Also, per protocol
within-group analysis showed a small positive effect (Cohen's d=.33) on
catastrophizing in the intervention group (P=.04) and no change in the control
group from the smartphone intervention baseline to 11-month follow-up. A
positive effect (Cohen's d=.73) on acceptance was found within the intervention
group (P<.001) but not in the control group. Small to large negative effects
were found within the control group on functioning and symptom levels, emotional
distress, and fatigue (P=.05) from the intervention baseline to the 11-month
follow-up.
CONCLUSION: The long-term results of this randomized trial are ambiguous. No
significant between-group effect was found on the study variables at 11-month
follow-up. However, the within-group analyses, comparing the baseline for the
smartphone intervention to the 11-month data, indicated changes in the desired
direction in catastrophizing and acceptance in the intervention group but not
within the control group. This study provides modest evidence supporting the
long-term effect of the intervention.
TRIAL REGISTRATION: Clinicaltrials.gov NCT01236209;
http://www.clinicaltrials.gov/ct2/show/NCT01236209 (Archived by WebCite at
http://www.webcitation.org/6FF7KUXo0). BACKGROUND: Chronic low back pain is a common chronic condition whose treatment
success can be improved by active involvement of patients. Patient involvement
can be fostered by web-based applications combining health information with
decision support or behaviour change support. These so-called Interactive Health
Communication Applications (IHCAs) can reach great numbers of patients at low
ficial cost and provide information and support at the time, place and
learning speed patients prefer. However, high attrition often seems to decrease
the effects of web-based interventions. Tailoring content and tone of IHCAs to
the individual patient ́s needs might improve usage and therefore effectiveness.
This study aims to evaluate a tailored IHCA for people with chronic low back
pain combining health information with decision support and behaviour change
support.
METHODS/DESIGN: The tailored IHCA will be tested regarding effectiveness and
usage against a standard website with identical content in a single-blinded
randomized trial with a parallel design. The IHCA contains information on
chronic low back pain and its treatment options including health behaviour
change recommendations. In the intervention group the content is delivered in
dialogue form, tailored to relevant patient characteristics (health literacy,
coping style). In the control group there is no tailoring, a standard web-page
is used for presenting the content. Participants are unaware of group
assignment. Eligibility criteria are age ≥ 18 years , self- reported chronic low
back pain, and Internet access. To detect the expected small effect (Cohen's
d = 0.2), the sample aims to include 414 patients, with assessments at baseline,
directly after the first on-page visit, and at 3-month follow-up using online
self-report questionnaires. It is expected that the tailored IHCA has larger
effects on knowledge and patient empowerment (primary outcomes) compared to a
standard website. Secondary outcomes are website usage, preparation for decision
making, and decisional conflict.
DISCUSSION: IHCAs can be a suitable way to promote knowledge about chronic low
back pain and self-management competencies. Results of the study can increase
the knowledge on how to develop IHCAs which are more useful and effective for
people suffering from chronic low back pain.
TRIAL REGISTRATION: International Clinical Trials Registry DRKS00003322. OBJECTIVES: To describe the development of an interactive, web-based
self-management intervention for opioid-treated, chronic pain patients with
aberrant drug-related behavior.
METHODS: Fifty-three chronic pain patients participated in either focus groups
(N = 23) or individual feedback sessions (N = 30). Focus groups probed interest
in and relevance of the planned content and structure of the program. Individual
session participants reviewed draft program modules and provided feedback on
acceptability, ease of use, and usefulness. Focus group transcripts were
thematically analyzed, and summary statistics were performed on feedback data.
RESULTS: Focus group participants stressed the need for additional pain
management strategies and emphasized themes consistent with planned program
content related to: 1) ambivalence about opioids; 2) reciprocal relationships
among cognition, mood, and pain; 3) importance of recognizing physical
limitations; and 4) effectiveness of goal setting for increasing motivation and
functioning. Participants also offered insights on: 5) the loss of identity due
to chronic pain; and 6) the desire to connect with pain peers to share
strategies for managing daily life. Feedback session data demonstrate that
participants believed that a web-based tool would be potentially useful and
acceptable, and that exposure to program sections significantly increased
participants' knowledge of key topics related to self-management of chronic
pain.
CONCLUSIONS: Results suggest the potential value of self-management for chronic
pain patients and the potential acceptability of web-based delivery of
intervention content. Focus group and feedback methodologies highlight the
usefulness of including potential program users in intervention development. BACKGROUND: It is estimated that 30% of adults in the United States experience
daily chronic pain. This results in a significant burden on the health care
system, in particular primary care, and on the workplace. Chronic pain
management with cognitive-behavioral psychological treatment is effective in
reducing pain intensity and interference, health-related quality of life, mood,
and return to work. However, the population of individuals with chronic pain far
exceeds the population of therapists that can provide this care face-to-face.
The use of tailored, Web-based interventions for the management of chronic pain
could address limitations to access by virtue of its unlimited scalability.
OBJECTIVE: To examine the effects of a tailored Web-based chronic pain
management program on subjective pain, activity and work interference, quality
of life and health, and stress.
METHODS: Eligible participants accessed the online pain management program and
informed consent via participating employer or health care benefit systems;
program participants who completed baseline, 1-, and 6-month assessments were
included in the study. Of the 645 participants, the mean age was 56.16 years (SD
12.83), most were female (447/645, 69.3%), and white (505/641, 78.8%). Frequent
pain complaints were joint (249/645, 38.6%), back (218/645, 33.8%), and
osteoarthritis (174/654, 27.0%). The online pain management program used
evidence-based theories of cognitive behavioral intervention, motivational
enhancement, and health behavior change to address self-management, coping,
medical adherence, social support, comorbidities, and productivity. The program
content was individually tailored on several relevant participant variables.
RESULTS: Both pain intensity (mean 5.30, SD 2.46), and unpleasantness (mean
5.43, SD 2.52) decreased significantly from baseline to 1-month (mean 4.16, SD
2.69 and mean 4.24, 2.81, respectively) and 6-month (mean 3.78, SD 2.79 and mean
3.78, SD 2.79, respectively) assessments (P<.001). The magnitude of the 6-month
effects were large. Trends for decreases in pain interference (36.8% reported
moderate or enormous interference) reached significance at 6 months (28.9%,
P<.001). The percentage of the sample reporting fair or poor quality of life
decreased significantly from 20.6% at baseline to 16.5% at 6 months (P=.006).
CONCLUSIONS: Results suggest that the tailored online chronic pain management
program showed promising effects on pain at 1 and 6 months posttreatment and
quality of life at 6 months posttreatment in this naturalistic study. Further
research is warranted to determine the significance and magnitude of the
intervention's effects in a randomized controlled trial. BACKGROUND: Fibromyalgia (FM) is a complex chronic pain condition that is
difficult to treat. The prevailing approach is an integration of
pharmacological, psycho-educational, and behavioral strategies. Information
technology offers great potential for FM sufferers to systemically monitor
symptoms as well as potential impacts of various management strategies.
AIMS: This study aimed to evaluate effects of a web-based, self-monitoring and
symptom management system (SMARTLog) that analyzes personal self-monitoring data
and delivers data-based feedback over time.
MATERIALS AND METHODS: Subjects were self-referred, anonymous, and recruited via
publicity on FM advocacy websites. Standardized instruments assessed health
status, self-efficacy, and locus of control at baseline and monthly during
participation. Subjects were encouraged to complete the SMARTLog several times
weekly. Within-subject, univariate, and multivariate analyses were used to
derive classification trees for each user associating specific behavior
variables with symptom levels over time.
RESULTS: Moderate use (3 times weekly x 3 months) increased likelihood of
clinically significant improvements in pain, memory, gastrointestinal problems,
depression, fatigue, and concentration; heavy use (4.5 times weekly x five
months) produced the above plus improvement in stiffness and sleep difficulties.
CONCLUSIONS: Individualized, web-based behavioral self-monitoring with
personally-tailored feedback can enable FM sufferers to significantly reduce
symptom levels over time. |
Is Weaver syndrome similar to Sotos? | Overgrowth conditions are a heterogeneous group of disorders characterised by increased growth and variable features, including macrocephaly, distinctive facial appearance and various degrees of learning difficulties and intellectual disability. Among them, Sotos and Weaver syndromes are clinically well defined and due to heterozygous mutations in NSD1 and EZH2, respectively. NSD1 and EZH2 are both histone-modifying enzymes | The syndromes of Sotos and Weaver are paradigmatic of the daily nosologic
difficulties faced by clinical geneticists attempting to diagnose and counsel,
and to give accurate prognoses in cases of extensive phenotypic overlap between
molecularly undefined entities. Vertebrate development is constrained into only
very few final or common developmental paths; therefore, no developmental
anomaly seen in humans is unique to ("pathognomonic" of) one syndrome. Thus, it
is not surprising that prenatal overgrowth occurs in several syndromes,
including the Sotos and Weaver syndromes. Are they sufficiently different in
other respects to allow the postulation of locus (rather than allele)
heterogeneity? Phenotypic data in both conditions are biased because of
ascertainment of propositi, and the apparent differences between them may be
entirely artificial as they were between the G and BBB syndromes. On the other
hand, the Sotos syndrome may be a cancer syndrome, the Weaver syndrome not
(though a neuroblastoma was reported in the latter); in the former there is also
remarkably advanced dental maturation rarely commented on in the latter. In
Weaver syndrome there are more conspicuous contractures and a facial appearance
that experts find convincingly different from that of Sotos individuals.
Nevertheless, the hypothesis of locus heterogeneity is testable; at the moment
we are inclined to favor the hypothesis of allele heterogeneity. An
international effort is required to map, isolate, and sequence the causal gene
or genes. Sotos syndrome is a childhood overgrowth syndrome characterized by a distinctive
facial appearance, height and head circumference >97th percentile, advanced bone
age, and developmental delay. Weaver syndrome is characterized by the same
criteria but has its own distinctive facial gestalt. Recently, a 2.2-Mb
chromosome 5q35 microdeletion, encompassing NSD1, was reported as the major
cause of Sotos syndrome, with intragenic NSD1 mutations identified in a minority
of cases. We evaluated 75 patients with childhood overgrowth, for intragenic
mutations and large deletions of NSD1. The series was phenotypically scored into
four groups, prior to the molecular analyses: the phenotype in group 1 (n=37)
was typical of Sotos syndrome; the phenotype in group 2 (n=13) was Sotos-like
but with some atypical features; patients in group 3 (n=7) had Weaver syndrome,
and patients in group 4 (n=18) had an overgrowth condition that was neither
Sotos nor Weaver syndrome. We detected three deletions and 32 mutations (13
frameshift, 8 nonsense, 2 splice-site, and 9 missense) that are likely to impair
NSD1 functions. The truncating mutations were spread throughout NSD1, but there
was evidence of clustering of missense mutations in highly conserved functional
domains between exons 13 and 23. There was a strong correlation between presence
of an NSD1 alteration and clinical phenotype, in that 28 of 37 (76%) patients in
group 1 had NSD1 mutations or deletions, whereas none of the patients in group 4
had abnormalities of NSD1. Three patients with Weaver syndrome had NSD1
mutations, all between amino acids 2142 and 2184. We conclude that intragenic
mutations of NSD1 are the major cause of Sotos syndrome and account for some
Weaver syndrome cases but rarely occur in other childhood overgrowth phenotypes. Overgrowth syndromes such as Beckwith-Wiedemann syndrome, Sotos syndrome, and
Weaver syndrome have an increased risk of neoplasia. Two previous cases of
neuroblastoma have been reported in children with Weaver syndrome. We present a
third description of a patient with Weaver syndrome and neuroblastoma. In a
child with phenotypic characteristics consistent with Weaver syndrome,
evaluation for neuroblastoma should be considered. Clinically, Weaver syndrome is closely related to Sotos syndrome, which is
frequently caused by mutations in NSD1. This gene also encodes a histone
methyltransferase, in this case with activity against histone H3 lysine 36. NSD1
is mutated in carcinoma of the upper aerodigestive tract
(www.sanger.ac.uk/genetics/CGP/cosmic/) and also fuses to NUP98 in acute myeloid
leukemia. Looking more widely, whole exome screens in lymphoma, multiple
myeloma, renal carcinoma and other maligcies have identified genes encoding
diverse histone modifiers as targets of somatic mutation. Strikingly, several of
these (e.g. MLL2, EP300, CREBBP, ASXL1) are also mutated in human developmental
disorders thus pointing towards a remarkable and unexpected convergence between
somatic and germline genetics. BACKGROUND: Overgrowth conditions are a heterogeneous group of disorders
characterised by increased growth and variable features, including macrocephaly,
distinctive facial appearance and various degrees of learning difficulties and
intellectual disability. Among them, Sotos and Weaver syndromes are clinically
well defined and due to heterozygous mutations in NSD1 and EZH2, respectively.
NSD1 and EZH2 are both histone-modifying enzymes. These two epigenetic writers
catalyse two specific post-translational modifications of histones: methylation
of histone 3 lysine 36 (H3K36) and lysine 27 (H3K27). We postulated that
mutations in writers of these two chromatin marks could cause overgrowth
conditions, resembling Sotos or Weaver syndromes, in patients with no NSD1 or
EZH2 abnormalities.
METHODS: We analysed the coding sequences of 14 H3K27 methylation-related genes
and eight H3K36 methylation-related genes using a targeted next-generation
sequencing approach in three Sotos, 11 'Sotos-like' and two Weaver syndrome
patients.
RESULTS: We identified two heterozygous mutations in the SETD2 gene in two
patients with 'Sotos-like' syndrome: one missense p.Leu1815Trp de novo mutation
in a boy and one nonsense p.Gln274* mutation in an adopted girl. SETD2 is
non-redundantly responsible for H3K36 trimethylation. The two probands shared
similar clinical features, including postnatal overgrowth, macrocephaly,
obesity, speech delay and advanced carpal ossification.
CONCLUSIONS: Our results illustrate the power of targeted next-generation
sequencing to identify rare disease-causing variants. We provide a compelling
argument for Sotos and Sotos-like syndromes as epigenetic diseases caused by
loss-of-function mutations of epigenetic writers of the H3K36 histone mark. |
Which enzyme is targeted by Evolocumab? | Evolocumab (AMG145) is a fully human monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9) that demonstrated marked reductions in plasma low-density lipoprotein cholesterol concentrations in statin-intolerant patients. | BACKGROUND: Evolocumab (AMG 145), a monoclonal antibody against proprotein
convertase subtilisin/kexin type 9 (PCSK9), significantly reduced low-density
lipoprotein cholesterol (LDL-C) in phase 2 studies of 12 weeks' duration. The
longer-term efficacy and safety of PCSK9 inhibition remain undefined.
METHODS AND RESULTS: Of 1359 randomized and dosed patients in the 4 evolocumab
phase 2 parent studies, 1104 (81%) elected to enroll into the Open-Label Study
of Long-term Evaluation Against LDL-C (OSLER) study. Regardless of their
treatment assignment in the parent study, patients were randomized 2:1 to
receive either open-label subcutaneous evolocumab 420 mg every 4 weeks with
standard of care (SOC) (evolocumab+SOC, n=736) or SOC alone (n=368). Ninety-two
percent of patients in the evolocumab+SOC group and 89% of patients in the SOC
group completed 52 weeks of follow-up. Patients who first received evolocumab in
OSLER experienced a mean 52.3% [SE, 1.8%] reduction in LDL-C at week 52
(P<0.0001). Patients who received 1 of 6 dosing regimens of evolocumab in the
parent studies and received evolocumab+SOC in OSLER had persistent LDL-C
reductions (mean reduction, 50.4% [SE, 0.8%] at the end of the parent study
versus 52.1% [SE, 1.0%] at 52 weeks; P=0.31). In patients who discontinued
evolocumab on entry into OSLER, LDL-C levels returned to near baseline levels.
Adverse events and serious adverse events occurred in 81.4% and 7.1% of the
evolocumab+SOC group patients and 73.1% and 6.3% of the SOC group patients,
respectively.
CONCLUSION: Evolocumab dosed every 4 weeks demonstrated continued efficacy and
encouraging safety and tolerability over 1 year of treatment in the largest and
longest evaluation of a PCSK9 inhibitor in hypercholesterolemic patients to
date.
CLINICAL TRIAL REGISTRATION URL: http://clinicaltrials.gov. Unique identifier:
NCT01439880. Since 2010, mAbs has documented the biopharmaceutical industry's progress in
transitioning antibody therapeutics to first Phase 3 clinical studies and
regulatory review, and its success at gaining first marketing approvals for
antibody-based products. This installment of the "Antibodies to watch" series
outlines events anticipated to occur between December 2013 and the end of 2014,
including first regulatory actions on marketing applications for vedolizumab,
siltuximab, and ramucirumab, as well as the Fc fusion proteins Factor IX-Fc and
Factor VIII-Fc; and the submission of first marketing applications for up to
five therapeutics (secukinumab, ch14.18, onartuzumab, necitumumab, gevokizumab).
Antibody therapeutics in Phase 3 studies are described, with an emphasis on
those with study completion dates in 2014, including antibodies targeting
interleukin-17a or the interleukin-17a receptor (secukinumab, ixekizumab,
brodalumab), proprotein convertase subtilisin/kexin type 9 (alirocumab,
evolocumab, bococizumab), and programmed death 1 receptor (lambrolizumab,
nivolumab). Five antibodies with US Food and Drug Administration's Breakthrough
Therapy designation (obinutuzumab, ofatumumab, lambrolizumab, bimagrumab,
daratumumab) are also discussed. AIMS: Prior trials with monoclonal antibodies to proprotein convertase
subtilizin/kexin type 9 (PCSK9) reported robust low density lipoprotein
cholesterol (LDL-C) reductions. However, the ability to detect potentially
beneficial changes in other lipoproteins such as lipoprotein (a), triglycerides,
high-density lipoprotein cholesterol (HDL-C), and apolipoprotein (Apo) A1, and
adverse events (AEs) was limited by sample sizes of individual trials. We report
a pooled analysis from four phase 2 studies of evolocumab (AMG 145), a
monoclonal antibody to PCSK9.
METHODS AND RESULTS: The trials randomized 1359 patients to various doses of
subcutaneous evolocumab every 2 weeks (Q2W) or 4 weeks (Q4W), placebo, or
ezetimibe for 12 weeks; 1252 patients contributed to efficacy and 1314, to
safety analyses. Mean percentage (95% CI) reductions in LDL-C vs. placebo ranged
from 40.2% (44.6%, 35.8%) to 59.3% (63.7%, 54.8%) among the evolocumab groups
(all P < 0.001). Statistically significant reductions in apolipoprotein B (Apo
B), non-high-density lipoprotein cholesterol (non-HDL-C), triglycerides and
lipoprotein (a) [Lp(a)], and increases in HDL-C were also observed. Adverse
events (AEs) and serious AEs with evolocumab were reported in 56.8 and 2.0% of
patients, compared with 49.2% and 1.2% with placebo. Adjudicated cardiac and
cerebrovascular events were reported in 0.3 and 0% in the placebo and 0.9 and
0.3% in the evolocumab arms, respectively.
CONCLUSION: In addition to LDL-C reduction, evolocumab, dosed either Q2W or Q4W,
demonstrated significant and favourable changes in other atherogenic and
anti-atherogenic lipoproteins, and was well tolerated over the 12-week treatment
period. INTRODUCTION: Despite the proven efficacy of statins, they are often reported to
be inadequate to achieve low-density lipoprotein cholesterol (LDL-C) goals
(especially in high-risk patients). Moreover, a large number of subjects cannot
tolerate statins or full doses of these drugs. Thus, there is a need for
additional effective LDL-C reducing agents.
AREAS COVERED: Evolocumab (AMG145) is a monoclonal antibody inhibiting the
proprotein convertase subtilisin/kexin type 9 that binds to the liver LDL
receptor and prevents it from normal recycling by targeting it for degradation.
Phase I and II trials revealed that its subcutaneous injection, either alone or
in combination with statins, is able to reduce LDL-C from 40 to 80%,
apolipoprotein B100 from 30 to 59% and lipoprotein(a) from 18 to 36% in a
dose-dependent manner. The incidence of side effects seems to be low and mainly
limited to nasopharyngitis, injection site pain, arthralgia and back pain.
EXPERT OPINION: Evolocumab is an innovative powerful lipid-lowering drug,
additive to statins and with an apparently large therapeutic range associated to
a low rate of mild adverse events. If available data will be confirmed in
long-term trials with strong outcomes, Evolocumab will provide an essential tool
to treat high-risk patients who need to reach ambitious LDL-C target. BACKGROUND: YUKAWA is a 12-week, randomized, double-blind, placebo-controlled,
phase 2 study evaluating the efficacy and safety of evolocumab (AMG 145) in
statin-treated Japanese patients at high cardiovascular risk.
METHODS AND RESULTS: 310 eligible patients receiving stable statin (±ezetimibe)
therapy were randomized to 1 of 6 treatments: placebo every 2 weeks (Q2W) or
monthly (QM), evolocumab 70 mg or 140 mg Q2W, or evolocumab 280 mg or 420 mg QM.
The primary endpoint was the percentage change from baseline in low-density
lipoprotein cholesterol (LDL-C) measured by preparative ultracentrifugation
(UC). Secondary endpoints included percentage changes in other lipid parameters
and the proportion of patients with LDL-C <1.8 mmol/L. Mean (SD) age was 62 (10)
years; 37% were female; and the mean (SD) baseline LDL-C was 3.7 (0.5) mmol/L
(by UC). Mean (SE) changes vs. placebo in LDL-C were greatest in the high-dose
groups: -68.6 (3.0) % and -63.9 (3.2) % with 140 mg Q2W and 420 mg QM dosing,
respectively. Up to 96% of evolocumab-treated patients achieved LDL-C <1.8
mmol/L. Adverse events (AEs) were more frequent in evolocumab (51%) vs. placebo
(38%) patients; 4 patients taking evolocumab discontinued treatment because of
an AE. There were no significant differences in AE rates based on dose or dose
frequency.
CONCLUSIONS: In Japanese patients at high cardiovascular risk with
hypercholesterolemia on stable statin therapy, evolocumab significantly reduced
LDL-C and was well tolerated during this 12-week study. BACKGROUND: Evolocumab, a monoclonal antibody that inhibits proprotein
convertase subtilisin/kexin type 9 (PCSK9), significantly reduced low-density
lipoprotein (LDL) cholesterol levels in phase 2 studies. We conducted a phase 3
trial to evaluate the safety and efficacy of 52 weeks of treatment with
evolocumab.
METHODS: We stratified patients with hyperlipidemia according to the risk
categories outlined by the Adult Treatment Panel III of the National Cholesterol
Education Program. On the basis of this classification, patients were started on
background lipid-lowering therapy with diet alone or diet plus atorvastatin at a
dose of 10 mg daily, atorvastatin at a dose of 80 mg daily, or atorvastatin at a
dose of 80 mg daily plus ezetimibe at a dose of 10 mg daily, for a run-in period
of 4 to 12 weeks. Patients with an LDL cholesterol level of 75 mg per deciliter
(1.9 mmol per liter) or higher were then randomly assigned in a 2:1 ratio to
receive either evolocumab (420 mg) or placebo every 4 weeks. The primary end
point was the percent change from baseline in LDL cholesterol, as measured by
means of ultracentrifugation, at week 52.
RESULTS: Among the 901 patients included in the primary analysis, the overall
least-squares mean (±SE) reduction in LDL cholesterol from baseline in the
evolocumab group, taking into account the change in the placebo group, was
57.0±2.1% (P<0.001). The mean reduction was 55.7±4.2% among patients who
underwent background therapy with diet alone, 61.6±2.6% among those who received
10 mg of atorvastatin, 56.8±5.3% among those who received 80 mg of atorvastatin,
and 48.5±5.2% among those who received a combination of 80 mg of atorvastatin
and 10 mg of ezetimibe (P<0.001 for all comparisons). Evolocumab treatment also
significantly reduced levels of apolipoprotein B, non-high-density lipoprotein
cholesterol, lipoprotein(a), and triglycerides. The most common adverse events
were nasopharyngitis, upper respiratory tract infection, influenza, and back
pain.
CONCLUSIONS: At 52 weeks, evolocumab added to diet alone, to low-dose
atorvastatin, or to high-dose atorvastatin with or without ezetimibe
significantly reduced LDL cholesterol levels in patients with a range of
cardiovascular risks. (Funded by Amgen; DESCARTES ClinicalTrials.gov number,
NCT01516879.). OBJECTIVES: The aim of this study was to compare biweekly and monthly evolocumab
with placebo and oral ezetimibe in patients with hypercholesterolemia in a phase
III trial.
BACKGROUND: Evolocumab, a fully human monoclonal antibody against proprotein
convertase subtilisin/kexin type 9 (PCSK9), significantly reduced LDL-C in phase
II trials.
METHODS: Patients 18 to 80 years of age with fasting low-density lipoprotein
cholesterol (LDL-C) ≥100 and <190 mg/dl and Framingham risk scores ≤10% were
randomized (1:1:1:1:2:2) to oral placebo and subcutaneous (SC) placebo biweekly;
oral placebo and SC placebo monthly; ezetimibe and SC placebo biweekly;
ezetimibe and SC placebo monthly; oral placebo and evolocumab 140 mg biweekly;
or oral placebo and evolocumab 420 mg monthly.
RESULTS: A total of 614 patients were randomized and administered doses.
Evolocumab treatment reduced LDL-C from baseline, on average, by 55% to 57% more
than placebo and 38% to 40% more than ezetimibe (p < 0.001 for all comparisons).
Evolocumab treatment also favorably altered other lipoprotein levels.
Treatment-emergent adverse events (AEs), muscle-related AEs, and laboratory
abnormalities were comparable across treatment groups.
CONCLUSIONS: In the largest monotherapy trial using a PCSK9 inhibitor to date,
evolocumab yielded significant LDL-C reductions compared with placebo or
ezetimibe and was well tolerated in patients with hypercholesterolemia.
(Monoclonal Antibody Against PCSK9 to Reduce Elevated LDL-C in Subjects
Currently Not Receiving Drug Therapy for Easing Lipid Levels-2 [MENDEL-2];
NCT01763827). OBJECTIVES: This study sought to evaluate the efficacy and safety of
subcutaneous evolocumab compared with oral ezetimibe in hypercholesterolemic
patients who are unable to tolerate effective statin doses.
BACKGROUND: Statin intolerance, which is predomitly due to muscle-related
side effects, is reported in up to 10% to 20% of patients. Evolocumab, a fully
human monoclonal antibody to proprotein convertase subtilisin/kexin type 9
(PCSK9), demonstrated marked reductions in plasma low-density lipoprotein
cholesterol (LDL-C) in a phase 2 study in statin-intolerant patients.
METHODS: The GAUSS-2 (Goal Achievement after Utilizing an Anti-PCSK9 Antibody in
Statin Intolerant Subjects) trial was a 12-week, double-blind study of
randomized patients (2:2:1:1) to evolocumab 140 mg every two weeks (Q2W) or
evolocumab 420 mg once monthly (QM) both with daily oral placebo or subcutaneous
placebo Q2W or QM both with daily oral ezetimibe 10 mg. Co-primary endpoints
were percent change from baseline in LDL-C at the mean of weeks 10 and 12, and
at week 12.
RESULTS: Three hundred seven patients (age 62 ± 10 years; LDL-C 193 ± 59 mg/dl)
were randomized. Evolocumab reduced LDL-C from baseline by 53% to 56%,
corresponding to treatment differences versus ezetimibe of 37% to 39%
(p <0.001). Muscle adverse events occurred in 12% of evolocumab-treated patients
and 23% of ezetimibe-treated patients. Treatment-emergent adverse events and
laboratory abnormalities were comparable across treatment groups.
CONCLUSIONS: Robust efficacy combined with favorable tolerability makes
evolocumab a promising therapy for addressing the largely unmet clinical need in
high-risk patients with elevated cholesterol who are statin intolerant. (Goal
Achievement After Utilizing an Anti-PCSK9 Antibody in Statin Intolerant
Subjects-2; NCT01763905). IMPORTANCE: In phase 2 studies, evolocumab, a fully human monoclonal antibody to
PCSK9, reduced LDL-C levels in patients receiving statin therapy.
OBJECTIVE: To evaluate the efficacy and tolerability of evolocumab when used in
combination with a moderate- vs high-intensity statin.
DESIGN, SETTING, AND PATIENTS: Phase 3, 12-week, randomized, double-blind,
placebo- and ezetimibe-controlled study conducted between January and December
of 2013 in patients with primary hypercholesterolemia and mixed dyslipidemia at
198 sites in 17 countries.
INTERVENTIONS: Patients (n = 2067) were randomized to 1 of 24 treatment groups
in 2 steps. Patients were initially randomized to a daily, moderate-intensity
(atorvastatin [10 mg], simvastatin [40 mg], or rosuvastatin [5 mg]) or
high-intensity (atorvastatin [80 mg], rosuvastatin [40 mg]) statin. After a
4-week lipid-stabilization period, patients (n = 1899) were randomized to
compare evolocumab (140 mg every 2 weeks or 420 mg monthly) with placebo (every
2 weeks or monthly) or ezetimibe (10 mg or placebo daily; atorvastatin patients
only) when added to statin therapies.
MAIN OUTCOMES AND MEASURES: Percent change from baseline in low-density
lipoprotein cholesterol (LDL-C) level at the mean of weeks 10 and 12 and at week
12.
RESULTS: Evolocumab reduced LDL-C levels by 66% (95% CI, 58% to 73%) to 75% (95%
CI, 65% to 84%) (every 2 weeks) and by 63% (95% CI, 54% to 71%) to 75% (95% CI,
67% to 83%) (monthly) vs placebo at the mean of weeks 10 and 12 in the moderate-
and high-intensity statin-treated groups; the LDL-C reductions at week 12 were
comparable. For moderate-intensity statin groups, evolocumab every 2 weeks
reduced LDL-C from a baseline mean of 115 to 124 mg/dL to an on-treatment mean
of 39 to 49 mg/dL; monthly evolocumab reduced LDL-C from a baseline mean of 123
to 126 mg/dL to an on-treatment mean of 43 to 48 mg/dL. For high-intensity
statin groups, evolocumab every 2 weeks reduced LDL-C from a baseline mean of 89
to 94 mg/dL to an on-treatment mean of 35 to 38 mg/dL; monthly evolocumab
reduced LDL-C from a baseline mean of 89 to 94 mg/dL to an on-treatment mean of
33 to 35 mg/dL. Adverse events were reported in 36%, 40%, and 39% of
evolocumab-, ezetimibe-, and placebo-treated patients, respectively. The most
common adverse events in evolocumab-treated patients were back pain, arthralgia,
headache, muscle spasms, and pain in extremity (all <2%).
CONCLUSIONS AND RELEVANCE: In this 12-week trial conducted among patients with
primary hypercholesterolemia and mixed dyslipidemia, evolocumab added to
moderate- or high-intensity statin therapy resulted in additional LDL-C
lowering. Further studies are needed to evaluate the longer-term clinical
outcomes and safety of this approach for LDL-C lowering.
TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01763866. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease that
plays an important role in the regulation of serum low-density lipoprotein (LDL)
cholesterol by downregulation of LDL receptor, and as such is considered a novel
target in cholesterol lowering therapy. In support of the drug development
program for Evolocumab, a fully human IgG₂ antibody that targets PCSK9, a
quantitative ELISA to measure free PCSK9 in human serum was developed. PCSK9
serves as a biomarker of pharmacological response during treatment, and
measuring levels of the free ligand post-dosing was of interest as an aid to
establishing the pharmacokinetic and pharmacodynamic properties of the
therapeutic. Given the complexities associated with the measurement of free
ligand in the presence of high concentrations of circulating drug, it was
important to challenge the method with experiments designed to assess ex vivo
conditions that have the potential to affect the binding equilibrium of drug and
ligand within test samples during routine sampling handling and assay
conditions. Herein, we report results of experiments that were conducted to
characterize the assay in alignment with regulatory guidance and industry
standards, and to establish evidence that the method is measuring the free
ligand in circulation at the time serum was collected. A robust supporting data
package was generated that demonstrates the method specifically and reproducibly
measures the free ligand, and is suitable for its intended use. Statins remain the cornerstone of hypolipidaemic drug treatment. The recent
American College of Cardiology (ACC)/American Heart Association (AHA) lipid
guidelines suggest using percent reductions of low density lipoprotein
cholesterol (LDL-C), according to cardiovascular disease (CVD) risk, rather than
specific LDL-C targets. These guidelines raised concerns and other Societies
(US, International, European) have not endorsed them. The implementation of
previous guidelines in clinical practice is suboptimal due to attitudes of
physicians and restrictions in health care systems. Monoclonal antibodies that
inhibit proprotein convertase subtilisin/ kexin type 9 (PCSK9), which degrades
the LDL receptor, like alirocumab and evolocumab, are in phase 3 trials. These
drugs are suitable for statin intolerant or resistant patients, heterozygous
familial hypercholesterolaemia (HeFH) and some forms of homozygous FH (HoFH).
Mipomersen (antisense oligonucleotide against apolipoprotein B) and lomitapide
(microsomal triglyceride transfer protein blocker) have already been approved
for HoFH. Eventually, silencing micro-RNA oligonucleotides may also become
available. The repair or silencing of genes implicated in hyperlipidaemia and/or
atherosclerosis is also on the horizon. If the new therapeutic options mentioned
above prove to be effective and safe then by combining them with statins and/or
ezetimibe we should be able to effectively control acquired or hereditary
dyslipidaemias and substantially further reduce CVD morbidity and mortality. Familial hypercholesterolemia (FH) is a common genetic disorder that presents
with robust increases in low-density lipoprotein cholesterol (LDL-C) and can
lead to premature cardiovascular disease. There are heterozygous and homozygous
forms. The diagnosis is usually made based on blood cholesterol levels, clinical
signs and family history. Genetic testing can be used to confirm the diagnosis.
Effective lowering of LDL-C in FH can prevent cardiovascular morbidity and
mortality, however, the disease remains greatly underdiagnosed. The mainstay of
pharmacologic therapy in FH patients is high-dose statins, which are often
combined with other lipid-lowering agents. The homozygous form is mainly treated
with lipid apheresis. Guideline-recommended target levels of LDL-C are often not
reached, making new treatment options desirable. Four classes of newer
lipid-lowering drugs offer promising advances in treating FH, namely the
apolipoprotein-B synthesis inhibitors (mipomersen), the microsomal transfer
protein inhibitors (lomitapide), the cholesterol ester transfer protein
inhibitors (anacetrapib, evacetrapib) and the proprotein convertase
subtilisin/kexin type 9 inhibitors (evolocumab, alirocumab). In this review, the
available evidence regarding the use of these drugs in patients with FH is
discussed, with particular focus on their efficacy and safety. INTRODUCTION: To answer the need of a better low-density lipoprotein (LDL)
cholesterol control in statin-treated patients at high risk for cardiovascular
disease, new injectable lipid-lowering drugs with innovative mechanisms of
action are in advanced phase of development or have just been approved.
AREAS COVERED: Evolocumab and alirocumab are fully human monoclonal antibodies
inhibiting the proprotein convertase subtilisin/kexin type 9 (PCSK9) that binds
to hepatic LDL receptor and prevents it from normal recycling by targeting it
for degradation. Mipomersen specifically binds to a segment of the human
apolipoprotein B100 messenger RNA, blocking the translation of the gene product.
Phase II (for evolocumab and alirocumab) and III (for evolocumab) trials show
that PCSK9 inhibitors are equally well tolerated, with adverse events mainly
limited to mild-to-moderate nasopharyngitis, injection-site pain, arthralgia and
back pain. Mipomersen use is mainly associated to hepatosteatosis, increased
transaminases (> 3 times the upper limit of normal), mild-to-moderate
injection-site reactions and flu-like symptoms.
EXPERT OPINION: PCSK9 inhibitors have demonstrated their good safety and
tolerability in a large number of subjects with different clinical conditions,
including statin-intolerance, enlarging their potential use in a broader range
of patients. Further data on long-term mipomersen safety are required. A decade after our discovery of the involvement of proprotein convertase
subtilisin/kexin type 9 (PCSK9) in cholesterol metabolism through the
identification of the first mutations leading to hypercholesterolemia, PCSK9 has
become one of the most promising targets in cholesterol and cardiovascular
diseases. This challenging work in the genetics of hypercholesterolemia paved
the way for a plethora of studies around the world allowing the characterization
of PCSK9, its expression, its impact on reducing the abundance of LDL receptor,
and the identification of loss-of-function mutations in hypocholesterolemia. We
highlight the different steps of this adventure and review the published
clinical trials especially those with the anti-PCSK9 antibodies evolocumab (AMG
145) and alirocumab (SAR236553/REGN727), which are in phase III trials. The
promising results in lowering LDL cholesterol levels raise hope that the PCSK9
adventure will lead, after the large and long-term ongoing phase III studies
evaluating efficacy and safety, to a new anticholesterol pharmacological class. Dyslipidaemia is a critical risk factor for the development of cardiovascular
complications such as ischemic heart disease and stroke. Although statins are
effective anti-dyslipidemic drugs, their usage is fraught with issues such as
failure of adequate lipid control in 30% of cases and intolerance in select
patients. The limited potential of other alternatives such as fibrates, bile
acid sequestrants and niacin has spurred the search for novel drug molecules
with better efficacy and safety. CETP inhibitors such as evacetrapib and
anacetrapib have shown promise in raising HDL besides LDL lowering property.
Microsomal triglyceride transfer protein (MTP) inhibitors such as lomitapide and
Apo CIII inhibitors such as mipomersen have recently been approved in Familial
Hypercholesterolemia but experience in the non-familial setting is pretty much
limited. One of the novel anti-dyslipidemic drugs which is greatly anticipated
to make a mark in LDL-C control is the PCSK9 inhibitors. Some of the
anti-dyslipidemic drugs which work by PCSK9 inhibition include evolocumab,
alirocumab and ALN-PCS. Other approaches that are being given due consideration
include farnesoid X receptor modulation and Lp-PLA2 inhibition. While it may not
be an easy proposition to dismantle statins from their current position as a
cholesterol reducing agent and as a drug to reduce coronary and cerebro-vascular
atherosclerosis, our improved understanding of the disease and appropriate
harnessing of resources using sound and robust technology could make rapid
in-roads in our pursuit of the ideal anti-dyslipidemic drug. The serine protease proprotein convertase subtilisin/kexin type 9 (PCSK9) binds
to the low-density lipoprotein (LDL) receptor (LDLR) and directs it to lysosomes
for intracellular degradation. This results in decreased numbers of LDLR
available on the hepatic cell surface to bind LDL particles and remove them from
the circulation and therefore to a subsequent increase in circulating
LDL-cholesterol (LDL-C) plasma levels. Since 2003, when the role of PCSK9 in
LDL-C metabolism was discovered, there have been major efforts to develop
efficient and safe methods to inhibit it. Amongst those, monoclonal antibodies
against PCSK9 are the furthest in development, with multiple phase 3 trials
already published and with cardiovascular endpoint trials currently underway.
Two fully human monoclonal antibodies, evolocumab (AMG 145) and alirocumab
(REGN727/SAR236553), have been extensively studied in a wide range of subjects,
such as those with statin intolerance, as an add-on to statin therapy, as a
monotherapy and in patients with familial hypercholesterolemia. PCSK9 antibodies
result in a consistent and robust decrease in LDL-C plasma levels ranging from
40% to 70%, either on top of statins or as a monotherapy. If the safety data
from the on-going phase 3 trials remain as reassuring as the data available till
now, PCSK9 antibodies will offer a novel, powerful therapeutic option to
decrease LDL-C plasma levels and, hopefully, cardiovascular risk. |
Are ultraconserved elements often transcribed? | Yes. Especially, a large fraction of non-exonic UCEs is transcribed across all developmental stages examined from only one DNA strand. | The identification of ultraconserved noncoding sequences in vertebrates has been
associated with developmental regulators and DNA-binding proteins. One of the
first of these was identified in the intergenic region between the Dlx-5 and
Dlx-6 genes, members of the Dlx/dll homeodomain-containing protein family. In
previous experiments, we showed that Sonic hedgehog treatment of forebrain
neural explants results in the activation of Dlx-2 and the novel noncoding RNA
(ncRNA), Evf-1. In this report, we show that the Dlx-5/6 ultraconserved region
is transcribed to generate an alternatively spliced form of Evf-1, the ncRNA
Evf-2. Evf-2 specifically cooperates with Dlx-2 to increase the transcriptional
activity of the Dlx-5/6 enhancer in a target and homeodomain-specific manner. A
stable complex containing the Evf-2 ncRNA and the Dlx-2 protein forms in vivo,
suggesting that the Evf-2 ncRNA activates transcriptional activity by directly
influencing Dlx-2 activity. These experiments identify a novel mechanism whereby
transcription is controlled by the cooperative actions of an ncRNA and a
homeodomain protein. The possibility that a subset of vertebrate ultraconserved
regions may function at both the DNA and RNA level to control key developmental
regulators may explain why ultraconserved sequences exhibit 90% or more
conservation even after 450 million years of vertebrate evolution. BACKGROUND: Ultraconserved elements (UCEs) are highly constrained elements of
mammalian genomes, whose functional role has not been completely elucidated yet.
Previous studies have shown that some of them act as enhancers in mouse, while
some others are expressed in both normal and cancer-derived human tissues. Only
one UCE element so far was shown to present these two functions concomitantly,
as had been observed in other isolated instances of single, non ultraconserved
enhancer elements.
RESULTS: We used a custom microarray to assess the levels of UCE transcription
during mouse development and integrated these data with published microarray and
next-generation sequencing datasets as well as with newly produced PCR
validation experiments. We show that a large fraction of non-exonic UCEs is
transcribed across all developmental stages examined from only one DNA strand.
Although the nature of these transcripts remains a mistery, our meta-analysis of
RNA-Seq datasets indicates that they are unlikely to be short RNAs and that some
of them might encode nuclear transcripts. In the majority of cases this function
overlaps with the already established enhancer function of these elements during
mouse development. Utilizing several next-generation sequencing datasets, we
were further able to show that the level of expression observed in non-exonic
UCEs is significantly higher than in random regions of the genome and that this
is also seen in other regions which act as enhancers.
CONCLUSION: Our data shows that the concurrent presence of enhancer and
transcript function in non-exonic UCE elements is more widespread than
previously shown. Moreover through our own experiments as well as the use of
next-generation sequencing datasets, we were able to show that the RNAs encoded
by non-exonic UCEs are likely to be long RNAs transcribed from only one DNA
strand. Although expression of non-protein-coding RNA (ncRNA) can be altered in human
cancers, their functional relevance is unknown. Ultraconserved regions are
noncoding genomic segments that are 100% conserved across humans, mice, and
rats. Conservation of gene sequences across species may indicate an essential
functional role, and therefore we evaluated the expression of ultraconserved
RNAs (ucRNA) in hepatocellular cancer (HCC). The global expression of ucRNAs was
analyzed with a custom microarray. Expression was verified in cell lines by
real-time PCR or in tissues by in situ hybridization using tissue microarrays.
Cellular ucRNA expression was modulated with siRNAs, and the effects on global
gene expression and growth of human and murine HCC cells were evaluated.
Fifty-six ucRNAs were aberrantly expressed in HepG2 cells compared with
nonmaligt hepatocytes. Among these ucRNAs, the greatest change was noted for
ultraconserved element 338 (uc.338), which was dramatically increased in human
HCC compared with noncancerous adjacent tissues. Although uc.338 is partially
located within the poly(rC) binding protein 2 (PCBP2) gene, the transcribed
ncRNA encoding uc.338 is expressed independently of PCBP2 and was cloned as a
590-bp RNA gene, termed TUC338. Functional gene annotation analysis indicated
predomit effects on genes involved in cell growth. These effects were
experimentally demonstrated in both human and murine cells. siRNA to TUC338
decreased both anchorage-dependent and anchorage-independent growth of HCC
cells. These studies identify a critical role for TUC338 in regulation of
transformed cell growth and of transcribed ultraconserved ncRNA as a unique
class of genes involved in the pathobiology of HCC. The relevance of the non-coding genome to human disease has mainly been studied
in the context of the widespread disruption of microRNA (miRNA) expression and
function that is seen in human cancer. However, we are only beginning to
understand the nature and extent of the involvement of non-coding RNAs (ncRNAs)
in disease. Other ncRNAs, such as PIWI-interacting RNAs (piRNAs), small
nucleolar RNAs (snoRNAs), transcribed ultraconserved regions (T-UCRs) and large
intergenic non-coding RNAs (lincRNAs) are emerging as key elements of cellular
homeostasis. Along with microRNAs, dysregulation of these ncRNAs is being found
to have relevance not only to tumorigenesis, but also to neurological,
cardiovascular, developmental and other diseases. There is great interest in
therapeutic strategies to counteract these perturbations of ncRNAs. OBJECTIVES: The development of colorectal cancer (CRC) is characterized by
multiple genetic alterations. Transcribed ultraconserved regions (T-UCRs) are a
subset of 481 sequences longer than 200 bp, which are absolutely conserved
between orthologous regions of human, rat and mouse genomes, and are actively
transcribed. It has recently been proven in cancer systems that differentially
expressed T-UCRs could alter the functional characteristics of maligt cells.
Genome-wide profiling revealed that T-UCRs have distinct signatures in human
leukemia and carcinoma.
METHODS: In our study, we examined the expression levels of uc.43, uc.73,
uc.134, uc.230, uc.339, uc.388 and uc.399 in 54 samples of primary colorectal
carcinomas and 15 samples of non-tumoral adjacent tissues by real-time PCR.
T-UCR expression levels were also correlated with commonly used
clinicopathological features of CRC.
RESULTS: Expression levels of uc.73 (p = 0.0139) and uc.388 (p = 0.0325) were
significantly decreased in CRC tissue, and uc.73 indicated a positive
correlation with overall survival (p = 0.0315). The lower expression of uc.388
was associated with the distal location of CRC (p = 0.0183), but no correlation
of any evaluated T-UCR with clinical stage, grade and tumor diameter was
observed.
CONCLUSION: Our preliminary results suggest that uc.73 and uc.388 could be
potential diagnostic and prognostic biomarkers in CRC patients. Much effort in cancer research has focused on the tiny part of our genome that
codes for mRNA. However, it has recently been recognized that microRNAs also
contribute decisively to tumorigenesis. Studies have also shown that epigenetic
silencing by CpG island hypermethylation of microRNAs with tumor suppressor
activities is a common feature of human cancer. The importance of other classes
of non-coding RNAs, such as long intergenic ncRNAs (lincRNAs) and transcribed
ultraconserved regions (T-UCRs) as altered elements in neoplasia, is also
gaining recognition. Thus, we wondered whether there were other ncRNAs
undergoing CpG island hypermethylation-associated inactivation in cancer cells.
We focused on the small nucleolar RNAs (snoRNAs), a subset of ncRNA with a wide
variety of cellular functions, such as chemical modification of RNA, pre-RNA
processing and control of alternative splicing. By data mining snoRNA databases
and the scientific literature, we selected 49 snoRNAs that had a CpG island
within ≤ 2 Kb or that were processed from a host gene with a 5'-CpG island.
Bisulfite genomic sequencing of multiple clones in normal colon mucosa and the
colorectal cancer cell line HCT-116 showed that 46 snoRNAs were equally
methylated in the two samples: completely unmethylated (n = 26) or fully
methylated (n = 20). Most interestingly, the host gene-associated 5'-CpG islands
of the snoRNAs SNORD123, U70C and ACA59B were hypermethylated in the cancer
cells but not in the corresponding normal tissue. CpG island hypermethylation
was associated with the transcriptional silencing of the respective snoRNAs.
Results of a DNA methylation microarray platform in a comprehensive collection
of normal tissues, cancer cell lines and primary maligcies demonstrated that
the observed hypermethylation of snoRNAs was a common feature of various tumor
types, particularly in leukemias. Overall, our findings indicate the existence
of a new subclass of ncRNAs, snoRNAs, that are targeted by epigenetic
inactivation in human cancer. Co-option of cis-regulatory modules has been suggested as a mechanism for the
evolution of expression sites during development. However, the extent and
mechanisms involved in mobilization of cis-regulatory modules remains elusive.
To trace the history of non-coding elements, which may represent candidate
ancestral cis-regulatory modules affirmed during chordate evolution, we have
searched for conserved elements in tunicate and vertebrate (Olfactores) genomes.
We identified, for the first time, 183 non-coding sequences that are highly
conserved between the two groups. Our results show that all but one element are
conserved in non-syntenic regions between vertebrate and tunicate genomes, while
being syntenic among vertebrates. Nevertheless, in all the groups, they are
significantly associated with transcription factors showing specific functions
fundamental to animal development, such as multicellular organism development
and sequence-specific DNA binding. The majority of these regions map onto
ultraconserved elements and we demonstrate that they can act as functional
enhancers within the organism of origin, as well as in cross-transgenesis
experiments, and that they are transcribed in extant species of Olfactores. We
refer to the elements as 'Olfactores conserved non-coding elements'. Recent data have linked hypoxia, a classic feature of the tumor
microenvironment, to the function of specific microRNAs (miRNAs); however,
whether hypoxia affects other types of noncoding transcripts is currently
unknown. Starting from a genome-wide expression profiling, we demonstrate for
the first time a functional link between oxygen deprivation and the modulation
of long noncoding transcripts from ultraconserved regions, termed
transcribed-ultraconserved regions (T-UCRs). Interestingly, several
hypoxia-upregulated T-UCRs, henceforth named 'hypoxia-induced noncoding
ultraconserved transcripts' (HINCUTs), are also overexpressed in clinical
samples from colon cancer patients. We show that these T-UCRs are predomitly
nuclear and that the hypoxia-inducible factor (HIF) is at least partly
responsible for the induction of several members of this group. One specific
HINCUT, uc.475 (or HINCUT-1) is part of a retained intron of the host
protein-coding gene, O-linked N-acetylglucosamine transferase, which is
overexpressed in epithelial cancer types. Consistent with the hypothesis that
T-UCRs have important function in tumor formation, HINCUT-1 supports cell
proliferation specifically under hypoxic conditions and may be critical for
optimal O-GlcNAcylation of proteins when oxygen tension is limiting. Our data
gives a first glimpse of a novel functional hypoxic network comprising
protein-coding transcripts and noncoding RNAs (ncRNAs) from the T-UCRs category. Long non-coding RNAs (lncRNAs) are transcripts longer than ~200 nucleotides with
little or no protein-coding capacity. Growing evidence shows that lncRNAs
present important function in development and are associated with many human
diseases such as cancers, Alzheimer disease, and heart diseases. Transcribed
ultraconserved region (T-UCR) transcripts are a novel class of lncRNAs
transcribed from ultraconserved regions (UCRs). UCRs are absolutely conserved
(100%) between the orthologous regions of the human, rat, and mouse genomes. The
UCRs are frequently located at fragile sites and at genomic regions involved in
cancers. Recent data suggest that T-UCRs are altered at the transcriptional
level in human tumorigenesis and the aberrant T-UCRs expression profiles can be
used to differentiate human cancer types. The profound understanding of T-UCRs
can throw new light on the pathogenesis of human cancers. |
What is the methyl donor of DNA (cytosine-5)-methyltransferases? | S-adenosyl-L-methionine (AdoMet, SAM) is the methyl donor of DNA (cytosine-5)-methyltransferases. DNA (cytosine-5)-methyltransferases catalyze the transfer of a methyl group from S-adenosyl-L-methionine to the C-5 position of cytosine residues in DNA. | The properties of the methyl-directed DNA (cytosine-5-)-methyltransferase (EC
2.1.1.37) suggest that it is the enzyme that maintains patterns of methylation
in the human genome. Proposals for the enzyme's mechanism of action suggest that
5-methyldeoxycytidine is produced from deoxycytidine via a dihydrocytosine
intermediate. We have used an oligodeoxynucleotide containing
5-fluorodeoxycytidine as a suicide substrate to capture the enzyme and the
dihydrocytosine intermediate. Gel retardation experiments demonstrate the
formation of the expected covalent complex between duplex DNA containing
5-fluorodeoxycytidine and the human enzyme. Formation of the complex was
dependent upon the presence of the methyl donor S-adenosylmethionine, suggesting
that it comprises an enzyme-linked 5-substituted dihydrocytosine moiety in DNA.
Dihydrocytosine derivatives are extremely labile toward hydrolytic deamination
in aqueous solution. Because C-to-T transition mutations are especially
prevalent at CG sites in human DNA, we have used high-performance liquid
chromatography to search for thymidine that might be generated by hydrolysis
during the methyl transfer reaction. Despite the potential for deamination
inherent in the formation of the intermediate, the methyltransferase did not
produce detectable amounts of thymidine. The data suggest that the ability of
the human methyltransferase to preserve genetic information when copying a
methylation pattern (i.e., its fidelity) is comparable to the ability of a
mammalian DNA polymerase to preserve genetic information when copying a DNA
sequence. Thus the high frequency of C-to-T transitions at CG sites in human DNA
does not appear to be due to the normal enzymatic maintece of methylation
patterns. In the absence of DNA substrate, the DNA methyltransferase (MTase) M.BspRI can
methylate itself using the methyl donor S-adenosyl-L-methionine (AdoMet). The
methyl group is transferred to two Cys residues of the MTase. The DNA (cytosine-5)-methyltransferase (m5C-MTase) M.BspRI is able to accept the
methyl group from the methyl donor S-adenosyl-L-methionine (AdoMet) in the
absence of DNA. Transfer of the methyl group to the enzyme is a slow reaction
relative to DNA methylation. Self-methylation is dependent on the native
conformation of the enzyme and is inhibited by S-adenosyl-L-homocysteine, DNA
and sulfhydryl reagents. Amino acid sequencing of proteolytic peptides obtained
from M.BspRI, which had been methylated with [methyl-3H]AdoMet, and thin layer
chromatography of the modified amino acid identified two cysteines, Cys156 and
Cys181 that bind the methyl group in form of S-methylcysteine. One of the
acceptor residues, Cys156 is the highly conserved cysteine which plays the role
of the catalytic nucleophile of m5C-MTases. The product of the dcm gene is the only DNA cytosine-C5 methyltransferase of
Escherichia coli K-12; it catalyses transfer of a methyl group from S-adenosyl
methionine (SAM) to the C-5 position of the inner cytosine residue of the
cognate sequence CCA/TGG. Sequence-specific, covalent crosslinking of the enzyme
to synthetic oligonucleotides containing 5-fluoro-2'-deoxycytidine is
demonstrated. This reaction is abolished if serine replaces the cysteine at
residue #177 of the enzyme. These results lend strong support to a catalytic
mechanism in which an enzyme sulfhydryl group undergoes Michael addition to the
C5-C6 double bond, thus activating position C-5 of the substrate DNA cytosine
residue for electrophilic attack by the methyl donor SAM. The enzyme is capable
of self-methylation in a DNA-independent reaction requiring SAM and the presence
of cysteine at position #177. Deoxycytosine methylase (Dcm) enzyme activity causes mutagenesis in vitro either
directly by enzyme-induced deamination of cytosine to uracil in the absence of
the methyl donor, S-adenosylmethionine (SAM), or indirectly through spontaneous
deamination of [5-methyl]cytosine to thymine. Using a Lac reversion assay, we
investigated the contribution of the first mechanism to Dcm mutagenesis in vivo
by lowering the levels of SAM. Escherichia coli SAM levels were lowered by
reducing SAM synthetase activity via the introduction of a metK84 allele or by
hydrolyzing SAM using the bacteriophage T3 SAM hydrolase. The metK84 strains
exhibited increased C-to-T mutagenesis. Expression of the T3 SAM hydrolase gene,
under the control of the arabinose-inducible P(BAD) promoter, effectively
reduced Dcm-mediated genomic DNA methylation. However, increased mutagenesis was
not observed until extremely high arabinose concentrations were used, and genome
methylation at Dcm sites was negligible. Rotation of a DNA or RNA nucleotide out of the double helix and into a protein
pocket ('base flipping') is a mechanistic feature common to some DNA/RNA-binding
proteins. Here, we report the structure of HhaI methyltransferase in complex
with DNA containing a south-constrained abasic carbocyclic sugar at the target
site in the presence of the methyl donor byproduct AdoHcy. Unexpectedly, the
locked south pseudosugar appears to be trapped in the middle of the flipping
pathway via the DNA major groove, held in place primarily through Van der Waals
contacts with a set of invariant amino acids. Molecular dynamics simulations
indicate that the structural stabilization observed with the south-constrained
pseudosugar will not occur with a north-constrained pseudosugar, which explains
its lowered binding affinity. Moreover, comparison of structural transitions of
the sugar and phosphodiester backbone observed during computational studies of
base flipping in the M.HhaI-DNA-AdoHcy ternary complex indicate that the
south-constrained pseudosugar induces a conformation on the phosphodiester
backbone that corresponds to that of a discrete intermediate of the
base-flipping pathway. As previous crystal structures of M.HhaI ternary complex
with DNA displayed the flipped sugar moiety in the antipodal north conformation,
we suggest that conversion of the sugar pucker from south to north beyond the
middle of the pathway is an essential part of the mechanism through which
flipping must proceed to reach its final destination. We also discuss the
possibility of the south-constrained pseudosugar mimicking a transition state in
the phosphodiester and sugar moieties that occurs during DNA base flipping in
the presence of M.HhaI. |
Is peripheral neuroepithelioma related to Ewing sarcoma? | Experimental data support the concept that Ewing sarcoma and peripheral neuroepithelioma are both peripheral primitive neuroectodermal neoplasms, differing only in the extent of neuroectodermal phenotype and morphological differentiation. | The histogenesis of Ewing sarcoma, the second most frequent bone tumor in
humans, remains controversial. Four Ewing cell lines were analyzed by
immunological methods. A panel of antibodies directed to T, B, and
myelomonocytic markers gave negative results. Surface antigens recognized on
Ewing cells were found to be related to the neuroectoderm lineage. Ganglioside
GD2, a marker of neuroectodermal tissues and tumors, was present on all lines.
These were also stained by the mouse monoclonal antibody HNK-1, which detects a
carbohydrate epitope present on several glycoconjugates of the nervous system,
including two glycoproteins, the myelin-associated glycoprotein and the neural
cell-adhesion molecule (N-CAM), and an acidic glycolipid of the peripheral
nervous system. The P61 monoclonal antibody, which reacts with a peptide moiety
of N-CAM, and a rabbit antiserum, raised to purified mouse N-CAM and not
recognizing the HNK-1-defined epitope, were also reactive. By contrast, all
antibodies specific for hematopoietic cell surface antigens were totally
negative. Besides these antigenic features, Ewing sarcoma cells are
characterized by a specific t(11;22)(q24;q12) translocation also observed in
neuroepithelioma, a neuroectodermal tumor, suggesting a possible evolutionary
related origin. The recent finding that the human N-CAM gene is located at the
vicinity of the breakpoint on chromosome 11 indicates that it might be involved
in genetic rearrangements occurring in this region. Ewing's sarcoma (ES) and peripheral neuroepithelioma (PN) are closely related
tumors, and it can be difficult to distinguish them from other small-round-cell
tumors (SRCTs). The glycoprotein p30/32MIC2 is highly, but not exclusively,
expressed in both ES and PN. Although the monoclonal antibody (Mab) HBA71, which
reacts with P30/32MIC2, has been reported to be relatively specific and highly
sensitive for both neoplasms, it is not readily available. Yet, Mab O13 is
commercially available, and it purportedly displays the same immunostaining
characteristics as HBA71. Because O13 has not been studied extensively, we
immunostained 21 ES/PNs and 147 other tumors or lesions that might show
SRCT-like features with O13. The results were similar to those reported for
HBA71. We found O13 to be 100% sensitive for ES/PN; and, no immunostaining was
noted on the SRCTs often included in the differential diagnosis of ES/PN (i.e.,
conventional neuroblastoma, rhabdomyosarcoma, and non-lymphoblastic lymphomas).
But, O13 immunoreacted with lymphoblastic lymphomas and some other tumors and
normal tissues. Nonetheless, this nonspecific reactivity should not cause
diagnostic problems, if an antibody panel containing anti-desmin and
anti-leukocyte common antigen is used in conjunction with O13. We conclude that,
within the proper diagnostic context, strong immunoreactivity of a SRCT tumor
for O13 should be considered good evidence that the tumor is ES/PN. Large group of small-round-cell tumours of soft tissues and bone represents a
complex diagnostic problem for the pathologists. Neuronal nature of many tumours
from this group is proven by means of new methods--immunophenotypic analysis,
tissue culture, cytogenetics. Peripheral neuroepithelioma, Ewing tumour,
primitive neuroectodermal tumour (PNET), Askin tumour belong to these neoplasms.
These tumours anatomically have no connection with the structures of the central
nervous system or autonomous sympathetic nervous system. Ewing's sarcoma of bone (ESB) and peripheral neuroepithelioma (PN) are
frequently considered to be different tumors. Some researchers have suggested
that PN is morphologically a neuroectodermal Ewing's sarcoma. We sought to
determine the extent of neuroectodermal features in conventional ESB on direct
patient material (25 cases) and to compare these tumors with a similar group of
readily diagnosed PNs (10 cases). Light microscopic, ultrastructural, and
immunophenotypic parameters were assessed and compared for both groups. The
avidin-biotin complex method was used. All tumors were antigenically intact
since all stained for vimentin or at least one marker. Neuroectodermal antigens
(neuron-specific enolase, Leu-7 [HNK-1], neurofilament 200 kd, and S100) were
found in nine of 10 cases of PN and in 17 of 25 cases of ESB. In ESB, an
atypical light microscopic appearance correlated with the presence of
neuroectodermal features in most cases, but neuroectodermal phenotype was more
frequent (68%) than morphological evidence of neuroectodermal differentiation
(36%). These data support the concept that ESB and PN are both peripheral
primitive neuroectodermal neoplasms, differing only in extent of neuroectodermal
phenotype and morphological differentiation. The eleventh cytogenetically analyzed Askin's tumour, diagnosed in a
two-year-old girl, is reported. Chromosomal analysis revealed a pseudodiploid
karyotype of tumour cells with translocations of t(11;22)(q24;q12) and
der(4)t(2;4)(q24;q35). The observed t(11;22)(q24;q12) is not only a unique
characteristic of all cytogenetically analyzed Askin's tumours but it also
occurs in 92-100% of peripheral neuroepithelioma and of Ewing's sarcoma,
irrespective of its osseous or extraosseous localization. This genetical
similarity further supports a nosological concept according to which Askin's
tumour, Ewing's sarcoma and peripheral neuroepithelioma represent phenotypic
variations of the same tumour, namely the peripheral primitive neuroectodermal
tumour. The term "small round-cell tumor" describes a group of highly aggressive
maligt tumors composed of relatively small and monotonous undifferentiated
cells with high nuclear to cytoplasmic ratios. This group includes Ewing's
sarcoma (ES), peripheral neuroepithelioma (aka, primitive neuroectodermal tumor
or extraskeletal ES), peripheral neuroblastoma ("classic-type"),
rhabdomyosarcoma, desmoplastic small round-cell tumor, lymphoma, leukemia,
small-cell osteosarcoma, small-cell carcinoma (either undifferentiated or
neuroendocrine), olfactory neuroblastoma, cutaneous neuroendocrine carcinoma
(aka, Merkel-cell carcinoma), small-cell melanoma, and mesenchymal
chondrosarcoma. Their clinical presentations often overlap, thus making a
definitive diagnosis problematic in some cases. Yet, a clear understanding of
their clinicopathologic features usually allows for a confident diagnosis,
especially if immunohistochemistry is used. The following is a review of the
immunohistochemistry of this small round-cell tumor group. Ewing's sarcoma/peripheral primitive neuroectodermal tumors (ES/pPNET) are a
group of small round cell sarcomas that show varying degrees of neuroectodermal
differentiation characterized by translocation involving the EWS gene. Uterine
ES/pPNET is a rare entity. A 29-year-old Chinese female who presented with
abdominal swelling and pain was diagnosed with a primary uterine ES/pPNET on the
basis of clinicopathologic, immunohistochemical and fluorescence in situ
hybridization (FISH) data. She was given a multimodal treatment, including
neoadjuvant, 95% cytoreductive, chemotherapy and radiotherapy. The patient is
currently alive with persistent disease after 18 months of follow-up. We
emphasized the crucial role of molecular techniques in the differential
diagnosis of small round cell tumors in this unusual location. Multimodal
therapy may improve the outcomes of patients. |
Which signaling pathway does sonidegib inhibit? | Sonidegib is a Hedghog signalling pathway inhibitor. | PURPOSE: This phase I trial was undertaken to determine the maximum tolerated
dose (MTD), dose-limiting toxicities (DLT), safety, tolerability,
pharmacokinetics, pharmacodynamics, and preliminary antitumor activity of the
novel smoothened inhibitor sonidegib (LDE225), a potent inhibitor of hedgehog
signaling, in patients with advanced solid tumors.
EXPERIMENTAL DESIGN: Oral sonidegib was administered to 103 patients with
advanced solid tumors, including medulloblastoma and basal cell carcinoma (BCC),
at doses ranging from 100 to 3,000 mg daily and 250 to 750 mg twice daily,
continuously, with a single-dose pharmacokinetics run-in period. Dose
escalations were guided by a Bayesian logistic regression model. Safety,
tolerability, efficacy, pharmacokinetics, and biomarkers in skin and tumor
biopsies were assessed.
RESULTS: The MTDs of sonidegib were 800 mg daily and 250 mg twice daily. The
main DLT of reversible grade 3/4 elevated serum creatine kinase (18% of
patients) was observed at doses ≥ the MTD in an exposure-dependent manner.
Common grade 1/2 adverse events included muscle spasm, myalgia, gastrointestinal
toxicities, increased liver enzymes, fatigue, dysgeusia, and alopecia. Sonidegib
exposure increased dose proportionally up to 400 mg daily, and displayed
nonlinear pharmacokinetics at higher doses. Sonidegib exhibited
exposure-dependent reduction in GLI1 mRNA expression. Tumor responses observed
in patients with medulloblastoma and BCC were associated with evidence of
hedgehog pathway activation.
CONCLUSIONS: Sonidegib has an acceptable safety profile in patients with
advanced solid tumors and exhibits antitumor activity in advanced BCC and
relapsed medulloblastoma, both of which are strongly associated with activated
hedgehog pathway, as determined by gene expression. Treatment of myelofibrosis (MF), a BCR-ABL-negative myeloproliferative neoplasm,
is challenging. The only current potentially curative option, allogeneic
hematopoietic stem cell transplant, is recommended for few patients. The
remaining patients are treated with palliative therapies to manage MF-related
anemia and splenomegaly. Identification of a mutation in the Janus kinase 2
(JAK2) gene (JAK2 V617F) in more than half of all patients with MF has prompted
the discovery and clinical development of inhibitors that target JAK2. Although
treatment with JAK2 inhibitors has been shown to improve symptom response and
quality of life in patients with MF, these drugs do not alter the underlying
disease; therefore, novel therapies are needed. The hedgehog (Hh) signaling
pathway has been shown to play a role in normal hematopoiesis and in the
tumorigenesis of hematologic maligcies. Moreover, inhibitors of the Hh
pathway have been shown to inhibit growth and self-renewal capacity in
preclinical models of MF. In a mouse model of MF, combined inhibition of the Hh
and JAK pathways reduced JAK2 mutant allele burden, reduced bone marrow
fibrosis, and reduced white blood cell and platelet counts. Preliminary clinical
data also suggest that inhibition of the Hh pathway, alone or in combination
with JAK2 inhibition, may enable disease modification in patients with MF.
Future studies, including one combining the Hh pathway inhibitor sonidegib and
the JAK2 inhibitor ruxolitinib, are underway in patients with MF and will inform
whether this combination approach can lead to true disease modification. PURPOSE: The absorption, distribution, metabolism, and excretion of the hedgehog
pathway inhibitor sonidegib (LDE225) were determined in healthy male subjects.
METHODS: Six subjects received a single oral dose of 800 mg ¹⁴C-sonidegib (74
kBq, 2.0 µCi) under fasting conditions. Blood, plasma, urine, and fecal samples
were collected predose, postdose in-house (days 1-22), and during 24-h visits
(weekly, days 29-43; biweekly, days 57-99). Radioactivity was determined in all
samples using accelerator mass spectrometry (AMS). Liquid chromatography-tandem
mass spectrometry (LC-MS/MS) was used to determine concentrations of sonidegib
and its main circulating metabolite in plasma. Metabolite profiles and
structures were determined in pooled plasma, urine, and fecal samples using
high-performance LC-AMS and LC-MS/MS, respectively.
RESULTS: A single dose of ¹⁴C-sonidegib was well tolerated in healthy subjects.
Unchanged sonidegib and total radioactivity reached peak concentration in plasma
by 2 and 3 h, respectively, and demonstrated similarly long half-lives of 319
and 331 h, respectively. Absorbed sonidegib (estimated 6-7 %) was extensively
distributed, and the approximate terminal volume of distribution was 2,500 L.
Unchanged sonidegib and a metabolite resulting from amide hydrolysis were the
major circulating components (36.4 and 15.4 % of radioactivity area under the
curve, respectively). Absorbed sonidegib was eliminated predomitly through
oxidative metabolism of the morpholine part and amide hydrolysis. Unabsorbed
sonidegib was excreted through the feces. Metabolites in excreta accounted for
4.49 % of the dose (1.20 % in urine, 3.29 % in feces). The recovery of
radioactivity in urine and feces was essentially complete (95.3 ± 1.93 % of the
dose in five subjects; 56.9 % of the dose in one subject with incomplete feces
collection suspected).
CONCLUSIONS: Sonidegib exhibited low absorption, was extensively distributed,
and was slowly metabolized. Elimination of absorbed sonidegib occurred largely
by oxidative and hydrolytic metabolism. BACKGROUND: Oral hedgehog inhibitors (HHIs) have shown significant efficacy in
the treatment of basal cell carcinoma (BCC). The evaluation of tumor regression
has been performed using clinical photography and radiographic scans.
Noninvasive imaging techniques, such as reflectance confocal microscopy (RCM)
and high-definition optical coherence tomography (HD-OCT), have been shown to be
valuable in detecting BCC in the skin.
OBJECTIVE: We monitored HHI-treated BCC using RCM and HD-OCT in vivo and
correlated morphologic changes seen on imaging to changes in traditional
histopathology.
METHODS: Six BCCs in 5 patients receiving HHIs (vismodegib or sonidegib) were
examined by RCM and HD-OCT before and during treatment. Characteristic features
were compared to histopathologic findings, including immunohistochemical
analysis.
RESULTS: Characteristic features of BCC in RCM and HD-OCT decreased or
disappeared completely during HHI treatment. Half of the clinically complete
responding tumors still featured tumor residue. Pseudocystic structures ("empty"
tumor nests in imaging) and widespread fibrosis (coarse bright fibers) were new
findings and could be confirmed by histopathology.
LIMITATIONS: Our study was limited by the number of tumor samples and imaging
timepoints.
CONCLUSION: Using RCM and HD-OCT, HHI-induced regression of BCC can be
visualized noninvasively in the skin. The formation of pseudocysts and fibrosis
were characteristic signs of BCC response to HHIs. PURPOSE: Distinct molecular subgroups of medulloblastoma, including hedgehog
(Hh) pathway-activated disease, have been reported. We identified and clinically
validated a five-gene Hh signature assay that can be used to preselect patients
with Hh pathway-activated medulloblastoma.
EXPERIMENTAL DESIGN: Gene characteristics of the Hh medulloblastoma subgroup
were identified through published bioinformatic analyses. Thirty-two genes shown
to be differentially expressed in fresh-frozen and formalin-fixed
paraffin-embedded tumor samples and reproducibly analyzed by RT-PCR were
measured in matched samples. These data formed the basis for building a
multi-gene logistic regression model derived through elastic net methods from
which the five-gene Hh signature emerged after multiple iterations. On the basis
of signature gene expression levels, the model computed a propensity score to
determine Hh activation using a threshold set a priori. The association between
Hh activation status and tumor response to the Hh pathway inhibitor sonidegib
(LDE225) was analyzed.
RESULTS: Five differentially expressed genes in medulloblastoma (GLI1, SPHK1,
SHROOM2, PDLIM3, and OTX2) were found to associate with Hh pathway activation
status. In an independent validation study, Hh activation status of 25
medulloblastoma samples showed 100% concordance between the five-gene signature
and Affymetrix profiling. Further, in medulloblastoma samples from 50 patients
treated with sonidegib, all 6 patients who responded were found to have
Hh-activated tumors. Three patients with Hh-activated tumors had stable or
progressive disease. No patients with Hh-nonactivated tumors responded.
CONCLUSIONS: This five-gene Hh signature can robustly identify Hh-activated
medulloblastoma and may be used to preselect patients who might benefit from
sonidegib treatment. The Hedgehog (Hh) signaling pathway is critical for embryonic development. In
adult tissues, Hh signaling is relatively quiescent with the exception of roles
in tissue maintece and repair. Aberrant activation of Hh signaling is
implicated in multiple aspects of transformation, including the maintece of
the cancer stem cell (CSC) phenotype. Preclinical studies indicate that CSCs
from many tumor types are sensitive to Hh pathway inhibition and that
Hh-targeted therapeutics block many aspects of transformation attributed to
CSCs, including drug resistance, relapse, and metastasis. However, to date, Hh
inhibitors, specifically those targeting Smoothened [such as vismodegib,
BMS-833923, saridegib (IPI-926), sonidegib/erismodegib (LDE225), PF-04449913,
LY2940680, LEQ 506, and TAK-441], have demonstrated good efficacy as monotherapy
in patients with basal cell carcinoma and medulloblastoma, but have shown
limited activity in other tumor types. This lack of success is likely due to
many factors, including a lack of patient stratification in early trials,
cross-talk between Hh and other oncogenic signaling pathways that can modulate
therapeutic response, and a limited knowledge of Hh pathway activation
mechanisms in CSCs from most tumor types. Here, we discuss Hh signaling
mechanisms in the context of human cancer, particularly in the maintece of
the CSC phenotype, and consider new therapeutic strategies that hold the
potential to expand considerably the scope and therapeutic efficacy of
Hh-directed anticancer therapy. BACKGROUND: Patients with advanced basal cell carcinoma have limited treatment
options. Hedgehog pathway signalling is aberrantly activated in around 95% of
tumours. We assessed the antitumour activity of sonidegib, a Hedgehog signalling
inhibitor, in patients with advanced basal cell carcinoma.
METHODS: BOLT is an ongoing multicentre, randomised, double-blind, phase 2
trial. Eligible patients had locally advanced basal cell carcinoma not amenable
to curative surgery or radiation or metastatic basal cell carcinoma. Patients
were randomised via an automated system in a 1:2 ratio to receive 200 mg or 800
mg oral sonidegib daily, stratified by disease, histological subtype, and
geographical region. The primary endpoint was the proportion of patients who
achieved an objective response, assessed in the primary efficacy analysis
population (patients with fully assessable locally advanced disease and all
those with metastatic disease) with data collected up to 6 months after
randomisation of the last patient. This trial is registered with
ClinicalTrials.gov, number NCT01327053.
FINDINGS: Between July 20, 2011, and Jan 10, 2013, we enrolled 230 patients, 79
in the 200 mg sonidegib group, and 151 in the 800 mg sonidegib group. Median
follow-up was 13·9 months (IQR 10·1-17·3). In the primary efficacy analysis
population, 20 (36%, 95% CI 24-50) of 55 patients receiving 200 mg sonidegib and
39 (34%, 25-43) of 116 receiving 800 mg sonidegib achieved an objective
response. In the 200 mg sonidegib group, 18 (43%, 95% CI 28-59) patients who
achieved an objective response, as assessed by central review, were noted among
the 42 with locally advanced basal cell carcinoma and two (15%, 2-45) among the
13 with metastatic disease. In the 800 mg group, 35 (38%, 95% CI 28-48) of 93
patients with locally advanced disease had an objective response, as assessed by
central review, as did four (17%, 5-39) of 23 with metastatic disease. Fewer
adverse events leading to dose interruptions or reductions (25 [32%] of 79
patients vs 90 [60%] of 150) or treatment discontinuation (17 [22%] vs 54 [36%])
occurred in patients in the 200 mg group than in the 800 mg group. The most
common grade 3-4 adverse events were raised creatine kinase (five [6%] in the
200 mg group vs 19 [13%] in the 800 mg group) and lipase concentration (four
[5%] vs eight [5%]). Serious adverse events occurred in 11 (14%) of 79 patients
in the 200 mg group and 45 (30%) of 150 patients in the 800 mg group.
INTERPRETATION: The benefit-to-risk profile of 200 mg sonidegib might offer a
new treatment option for patients with advanced basal cell carcinoma, a
population that is difficult to treat.
FUNDING: Novartis Pharmaceuticals Corporation. |
In which phase of the cell cycle arrest is impaired in Fanconi anemia? | In response to damage induced by DNA cross-linking agents, the S-phase checkpoint is inefficient in Fanconi anemia (FA) cells, leading to accumulation of secondary lesions, such as single- and double-strand breaks and gaps. The prolonged time in G2 phase seen in FA cells therefore exists in order to allow the cells to remove lesions which accumulated during the preceding abnormal S phase. | Fanconi anemia (FA) is a genetic disorder defined by cellular hypersensitivity
to DNA cross-linking agents, such as mitomycin C (MMC). MMC causes increased FA
cell death, chromosome breakage, and accumulation in the G2 phase of the cell
cycle. Recently, Fanconi anemia complementation group C (fac) gene knock-out
mice have been developed, and SV40-transformed fibroblasts were established from
fac homozygous knock-out (-/-), heterozygous (+/-), and wild-type mice (+/+).
MMC sensitivity of these cell lines was assessed by three methods:
colony-formation assay in the presence of MMC, chromosome breakage, and cell
cycle analysis to detect G2 phase arrest. The fac knock-out fibroblasts (-/-)
showed a significantly higher sensitivity to MMC than did fibroblasts from
wild-type (+/+) or heterozygous (+/-) mice (three experiments). In addition, we
analyzed hematopoietic progenitor colony assays of bone marrow cells from fac
knock-out (-/-) and heterozygous (+/-) mice. CFU-E, BFU-E, and CFU-GM colony
formation from fac nullizygous mouse progenitors was markedly diminished by MMC
when compared to growth of progenitors from heterozygous mice. These results
show that fac knock-out mouse cells mimic the behavior of human FA-C patient
cells in terms of MMC hypersensitivity. The fac knock-out mouse may be used to
model some aspects of human FA and should be useful for understanding the
function of the FAC protein. Fanconi anemia (FA) is an inherited cancer-susceptibility disorder,
characterized by genomic instability, hypersensitivity to DNA cross-linking
agents, and a prolonged G2 phase of the cell cycle. We observed a marked
dose-dependent accumulation of FA cells in the G2 compartment after treatment
with 4,5',8-trimethylpsoralen (Me(3)Pso) in combination with 365 nm irradiation.
Using bivariate DNA distribution methodology, we determined the proportion of
replicating and arresting S-phase cells and observed that, whereas normal cells
arrested DNA replication in the presence of Me(3)Pso cross-links and
monoadducts, FA lymphoblasts failed to arrest DNA synthesis. Taken together, the
above data suggest that, in response to damage induced by DNA cross-linking
agents, the S-phase checkpoint is inefficient in FA cells. This would lead to
accumulation of secondary lesions, such as single- and double-strand breaks and
gaps. The prolonged time in G2 phase seen in FA cells therefore exists in order
to allow the cells to remove lesions which accumulated during the preceding
abnormal S phase. Fanconi anemia (FA) is a human genetic disorder characterized by
hypersensitivity to DNA crosslinking agents. Its cellular phenotypes include
increased chromosome breakage and a marked cell-cycle delay with 4N DNA content
after introduction of interstrand DNA crosslinks (ICL). To further understand
the nature of this delay previously described as a G2/M arrest, we introduced
ICL specifically during G2 and monitored the cells for passage into mitosis. Our
results showed that, even at the highest doses, postreplication ICL produced
neither G2/M arrest nor chromosome breakage in FA-A or FA-C cells. This suggests
that, similar to wild-type cells, DNA replication is required to trigger both
responses. Therefore, the 4N cell DNA content observed in FA cells after ICL
treatment also represents incomplete DNA replication and arrest in late S phase.
FA fibroblasts from complementation groups A and C were able to recover from the
ICL-induced cell-cycle arrest, but took approximately 3 times longer than
controls. These results indicate that the FA pathway is required for the
efficient resolution of ICL-induced S-phase arrest. The genetic syndrome Fanconi anemia (FA) is characterized by aplastic anemia,
cancer predisposition and hypersensitivity to DNA interstrand crosslinks (ICLs).
FA proteins (FANCs) are thought to work in pathway(s) essential for dealing with
crosslinked DNA. FANCs interact with other proteins involved in both DNA repair
and S-phase checkpoint such as BRCA1, ATM and the RAD50/MRE11/NBS1 (RMN)
complex. We deciphered the previously undefined pathway(s) leading to the
ICLs-induced S-phase checkpoint and the role of FANCs in this process. We found
that ICLs activate a branched pathway downstream of the ATR kinase: one branch
depending on CHK1 activity and the other on the FANCs-RMN complex. The transient
slow-down of DNA synthesis was abolished in cells lacking ATR, whereas
CHK1-siRNA-treated cells, NBS1 or FA cells showed partial S-phase arrest. CHK1
RNAi in NBS1 or FA cells abolished the S-phase checkpoint, suggesting that CHK1
and FANCs/NBS1 proteins work on parallel pathways. Furthermore, we found that
ICLs trigger ATR-dependent FANCD2 phosphorylation and FANCD2/ATR colocalization.
This study demonstrates a novel relationship between the FA pathway(s) and the
ATR kinase. |
Which DNA sequences are more prone for the formation of R-loops? | R-loops, transcriptionally-induced RNA:DNA hybrids, occurring at repeat tracts (CTG)n, (CAG)n, (CGG)n, (CCG)n and (GAA)n, are associated with diseases including myotonic dystrophy, Huntington's disease, fragile X and Friedreich's ataxia. Physiological R-loop formation at CpG island promoters can contribute to DNA replication origin specification at these regions, the most efficient replication initiation sites in mammalian cells. R-loops may also possess beneficial effects, as their widespread formation has been detected over CpG island promoters in human genes. R-loops are particularly enriched over G-rich terminator elements. | Immunoglobulin H class-switch recombination (CSR) occurs between switch regions
and requires transcription and activation-induced cytidine deaminase (AID).
Transcription through mammalian switch regions, because of their GC-rich
composition, generates stable R-loops, which provide single-stranded DNA
substrates for AID. However, we show here that the Xenopus laevis switch region
S(mu), which is rich in AT and not prone to form R-loops, can functionally
replace a mouse switch region to mediate CSR in vivo. X. laevis S(mu)-mediated
CSR occurred mostly in a region of AGCT repeats targeted by the AID-replication
protein A complex when transcribed in vitro. We propose that AGCT is a
primordial CSR motif that targets AID through a non-R-loop mechanism involving
an AID-replication protein A complex. R-loops are structures where an RNA strand is base paired with one DNA strand of
a DNA duplex, leaving the displaced DNA strand single-stranded. Stable R-loops
exist in vivo at prokaryotic origins of replication, the mitochondrial origin of
replication, and mammalian immunoglobulin (Ig) class switch regions in activated
B lymphocytes. All of these R-loops arise upon generation of a G-rich RNA strand
by an RNA polymerase upon transcription of a C-rich DNA template strand. These
R-loops are of significant length. For example, the R-loop at the col E1 origin
of replication appears to be about 140 bp. Our own lab has focused on class
switch regions, where the R-loops can extend well over a kilobase in length.
Here, methods are described for detection and analysis of R-loops in vitro and
in vivo. Transcription stimulates the genetic instability of trinucleotide repeat
sequences. However, the mechanisms leading to transcription-dependent repeat
length variation are unclear. We demonstrate, using biochemical and genetic
approaches, that the formation of stable RNA.DNA hybrids enhances the
instability of CTG.CAG repeat tracts. In vitro transcribed CG-rich repeating
sequences, unlike AT-rich repeats and nonrepeating sequences, form stable,
ribonuclease A-resistant structures. These RNA.DNA hybrids are eliminated by
ribonuclease H treatment. Mutation in the rnhA1 gene that decreases the activity
of ribonuclease HI stimulates the instability of CTG.CAG repeats in E. coli.
Importantly, the effect of ribonuclease HI depletion on repeat instability
requires active transcription. We also showed that transcription-dependent
CTG.CAG repeat instability in human cells is stimulated by siRNA knockdown of
RNase H1 and H2. In addition, we used bisulfite modification, which detects
single-stranded DNA, to demonstrate that the nontemplate DNA strand at
transcribed CTG.CAG repeats remains partially single-stranded in human genomic
DNA, thus indicating that it is displaced by an RNA.DNA hybrid. These studies
demonstrate that persistent hybrids between the nascent RNA transcript and the
template DNA strand at CTG.CAG tracts promote instability of DNA trinucleotide
repeats. In this issue of Molecular Cell, Ginno et al. (2012) describe unusual sequence
features at promoter CpG islands that can lead to formation of persistent
RNA-DNA hybrids (R loops), which are proposed to prevent genomic DNA
methylation. Friedreich ataxia (FRDA) and Fragile X syndrome (FXS) are among 40 diseases
associated with expansion of repeated sequences (TREDs). Although their
molecular pathology is not well understood, formation of repressive chromatin
and unusual DNA structures over repeat regions were proposed to play a role. Our
study now shows that RNA/DNA hybrids (R-loops) form in patient cells on expanded
repeats of endogenous FXN and FMR1 genes, associated with FRDA and FXS. These
transcription-dependent R-loops are stable, co-localise with repressive H3K9me2
chromatin mark and impede RNA Polymerase II transcription in patient cells. We
investigated the interplay between repressive chromatin marks and R-loops on the
FXN gene. We show that decrease in repressive H3K9me2 chromatin mark has no
effect on R-loop levels. Importantly, increasing R-loop levels by treatment with
DNA topoisomerase inhibitor camptothecin leads to up-regulation of repressive
chromatin marks, resulting in FXN transcriptional silencing. This provides a
direct molecular link between R-loops and the pathology of TREDs, suggesting
that R-loops act as an initial trigger to promote FXN and FMR1 silencing. Thus
R-loops represent a common feature of nucleotide expansion disorders and provide
a new target for therapeutic interventions. Pif1 family helicases are conserved from bacteria to humans. Here, we report a
novel DNA patrolling activity which may underlie Pif1's diverse functions: a
Pif1 monomer preferentially anchors itself to a 3'-tailed DNA junction and
periodically reel in the 3' tail with a step size of one nucleotide, extruding a
loop. This periodic patrolling activity is used to unfold an intramolecular
G-quadruplex (G4) structure on every encounter, and is sufficient to unwind
RNA-DNA heteroduplex but not duplex DNA. Instead of leaving after G4 unwinding,
allowing it to refold, or going beyond to unwind duplex DNA, Pif1 repeatedly
unwinds G4 DNA, keeping it unfolded. Pif1-induced unfolding of G4 occurs in
three discrete steps, one strand at a time, and is powerful enough to overcome
G4-stabilizing drugs. The periodic patrolling activity may keep Pif1 at its site
of in vivo action in displacing telomerase, resolving R-loops, and keeping G4
unfolded during replication, recombination and repair.DOI:
http://dx.doi.org/10.7554/eLife.02190.001. The uticipated widespread occurrence of stable hybrid DNA/RNA structures
(R-loops) in human cells and the increasing evidence of their involvement in
several human maligcies have invigorated the research on R-loop biology in
recent years. Here we propose that physiological R-loop formation at CpG island
promoters can contribute to DNA replication origin specification at these
regions, the most efficient replication initiation sites in mammalian cells.
Quite likely, this occurs by the strand-displacement reaction activating the
formation of G-quadruplex structures that target the origin recognition complex
(ORC) in the single-stranded conformation. In agreement with this, we found that
R-loops co-localize with the ORC within the same CpG island region in a
significant fraction of these efficient replication origins, precisely at the
position displaying the highest density of G4 motifs. This scenario builds on
the connection between transcription and replication in human cells and suggests
that R-loop dysregulation at CpG island promoter-origins might contribute to the
phenotype of DNA replication abnormalities and loss of genome integrity detected
in cancer cells. |
Mutation of which gene is implicated in the familial isolated pituitary adenoma? | Mutation of aryl hydrocarbon receptor interacting protein (AIP) gene was implicated in the familial isolated pituitary adenoma (FIPA) syndrome. About 20% of the families with FIPA harbor inactivating mutation in AIP gene. | CONTEXT: An association between germline aryl hydrocarbon receptor-interacting
protein (AIP) gene mutations and pituitary adenomas was recently shown.
OBJECTIVE: The objective of the study was to assess the frequency of AIP gene
mutations in a large cohort of patients with familial isolated pituitary adenoma
(FIPA).
DESIGN: This was a multicenter, international, collaborative study.
SETTING: The study was conducted in 34 university endocrinology and genetics
departments in nine countries.
PATIENTS: Affected members from each FIPA family were studied. Relatives of
patients with AIP mutations underwent AIP sequence analysis.
MAIN OUTCOME MEASURES: Presence/absence and description of AIP gene mutations
were the main outcome measures.
INTERVENTION: There was no intervention.
RESULTS: Seventy-three FIPA families were identified, with 156 patients with
pituitary adenomas; the FIPA cohort was evenly divided between families with
homogeneous and heterogeneous tumor expression. Eleven FIPA families had 10
germline AIP mutations. Nine mutations, R16H, G47_R54del, Q142X, E174frameshift,
Q217X, Q239X, K241E, R271W, and Q285frameshift, have not been described
previously. Tumors were significantly larger (P = 0.0005) and diagnosed at a
younger age (P = 0.0006) in AIP mutation-positive vs. mutation-negative
subjects. Somatotropinomas predominated among FIPA families with AIP mutations,
but mixed GH/prolactin-secreting tumors, prolactinomas, and nonsecreting
adenomas were also noted. Approximately 85% of the FIPA cohort and 50% of those
with familial somatotropinomas were negative for AIP mutations.
CONCLUSIONS: AIP mutations, of which nine new mutations have been described
here, occur in approximately 15% of FIPA families. Although pituitary tumors
occurring in association with AIP mutations are predomitly somatotropinomas,
other tumor types are also seen. Further study of the impact of AIP mutations on
protein expression and activity is necessary to elucidate their role in
pituitary tumorigenesis in FIPA. Pituitary adenomas occur in a familial setting in multiple endocrine neoplasia
type 1 (MEN1) and Carney's complex (CNC), which occur due to mutations in the
genes MEN1 and PRKAR1A respectively. Isolated familial somatotropinoma (IFS) is
also a well-described clinical syndrome related only to patients with
acrogigantism. Pituitary adenomas of all types--not limited to IFS--can occur in
a familial setting in the absence of MEN1 and CNC; this phenotype is termed
familial isolated pituitary adenomas (FIPA). Over the past 7 years, we have
described over 90 FIPA kindreds. In FIPA, both homogeneous and heterogeneous
pituitary adenoma phenotypes can occur within families; virtually all FIPA
kindreds contain at least one prolactinoma or somatotropinoma. FIPA differs from
MEN1 in terms of a lower proportion of prolactinomas and more frequent
somatotropinomas in the FIPA cohort. Patients with FIPA are significantly
younger at diagnosis and have significantly larger pituitary adenomas than
matched sporadic pituitary adenoma counterparts. A minority of FIPA families
overall (15%) exhibit mutations in the aryl hydrocarbon receptor-interacting
protein (AIP) gene; AIP mutations are present in only half of IFS kindreds
occurring as part of the FIPA cohort. In families with AIP mutations, pituitary
adenomas have a penetrance of over 50%. AIP mutations are extremely rare in
patients with sporadic pituitary adenomas. This review deals with pituitary
adenomas that occur in a familial setting, describes in detail the clinical,
pathological, and genetic features of FIPA, and addresses aspects of the
clinical approach to FIPA families with and without AIP mutations. Pituitary adenomas can occur in a familial context, or they can be isolated
cases, sometimes due to a predisposing syndrome. In multiple endocrine neoplasia
type 1, they often associate with a mutation of the menin gene, a
tumor-suppressing gene. A new germinal mutation predisposing to the development
of multiple endocrine neoplasias has recently been identified in MENI-negative
subjects on the gene CDKN1B encoding for p27(kip1)protein. Carney Complex
syndrome--a rare disease--is in more than 60% of the cases linked to the
inactivation mutation of a gene located on 17q22-24 that encodes the regulatory
subunit 1 of protein kinase A, PRKARIA. Isolated familial pituitary adenomas
represent 1.9 to 3.2% of the population of subjects presenting a pituitary
adenoma. Low penetrance non-sense mutations, Q14X, IVS3-IG>A and R304X, in
11q12-11q13 region encoding AIP protein, (Aryl hydrocarbon receptor Interacting
Protein), have been described by Vierimaa et al, in Finish patients with
pituitary adenoma predispositions. Familial pituitary adenoma is a rare syndrome which may present either as
isolated lesions, or in association with other endocrine tumors, for example in
the frame of multiple endocrine neoplasia (MEN-1) or Carney complex (CNC). The
most frequently described forms of familial isolated pituitary adenoma (FIPA)
are familial somatotropinomas or prolactinomas. Recently, some cases of familial
isolated somatotropinoma have been associated with germline mutations in the
aryl hydrocarbon receptor interacting protein (AIP) gene. The present report
shows heterogeneous FIPA with 3 subtypes of tumor in 3 individuals of the same
family: somatotropinoma in the proband, giant prolactinoma in a brother, and
gonadotroph cell macroadenoma in the father. A prospective survey also suggested
the occurrence of a silent microadenoma in the proband's sister. Clinical
screening was performed in the 3 affected members, the 4th suspected case, and 9
additional, asymptomatic relatives. They had no clinical evidence of associated
endocrine lesion suggesting MEN-1 or CNC. Genetic screening for germline
mutation of the MEN-1, the gene encoding the protein kinase A (PKA) type 1 alpha
regulatory subunit (R1 alpha) (PRKAR1alpha) and AIP gene was negative in 2
affected members. In conclusion, these data suggest that familial pituitary
adenomas can occur with a heterogeneous functional pattern that is distinguished
from MEN-1 or CNC. The absence of mutation of the recently described AIP gene
suggests the implication of other predisposing gene(s). Collaborative,
multicentric studies are needed to further define the location of gene(s)
involved in heterogeneous FIPA. Familial pituitary adenomas occurr in the classical syndromes of MEN1 and Carney
Complex as well as in Familial Isolated Pituitary Adenomas (FIPA), an autosomal
domit disease with incomplete penetrance. In some families and also rarely in
sporadic tumours germline mutations of a gene located on chromosome 11q13 known
as the aryl hydrocarbon receptor interacting protein have been found. This
article discusses the AIP mutations in these groups and the different molecular
interactions of AIP that may play a role in pituitary tumour formation. Familial isolated pituitary adenoma (FIPA) is an autosomal domit condition
with variable genetic background and incomplete penetrance. Germline mutations
of the aryl hydrocarbon receptor interacting protein (AIP) gene have been
reported in 15-40% of FIPA patients. Limited data are available on the
functional consequences of the mutations or regarding the regulation of the AIP
gene. We describe a large cohort of FIPA families and characterize missense and
silent mutations using minigene constructs, luciferase and beta-galactosidase
assays, as well as in silico predictions. Patients with AIP mutations had a
lower mean age at diagnosis (23.6+/-11.2 years) than AIP mutation-negative
patients (40.4+/-14.5 years). A promoter mutation showed reduced in vitro
activity corresponding to lower mRNA expression in patient samples. Stimulation
of the protein kinase A-pathway positively regulates the AIP promoter. Silent
mutations led to abnormal splicing resulting in truncated protein or reduced AIP
expression. A two-hybrid assay of protein-protein interaction of all missense
variants showed variable disruption of AIP-phosphodiesterase-4A5 binding. In
summary, exonic, promoter, splice-site, and large deletion mutations in AIP are
implicated in 31% of families in our FIPA cohort. Functional characterization of
AIP changes is important to identify the functional impact of gene sequence
variants. The identification of mutations in the Aryl hydrocarbon receptor interacting
protein (AIP) gene in a subset of familial isolated pituitary adenoma (FIPA)
cases has recently expanded our understanding of the pathophysiology of
inherited pituitary adenoma disorders. However, a genetic cause of has not yet
been determined in the majority (85%) of FIPA families and half of the families
with isolated familial somatotropinoma. Several studies and reviews have
assessed the genetic and clinical features of AIP-mutated FIPA patients, which
range from a complete lack of symptoms in adult/elderly individuals to large,
aggressive early-onset pituitary tumors. In this study, we aimed to briefly
revise the data available for the 11q13 locus and other additional loci that
have been implicated in genetic susceptibility to FIPA: 2p16-12; 3q28;
4q32.3-4q33; chr 5, 8q12.1, chr 14, 19q13.4 and 21q22.1. These candidate regions
may contain unidentified gene(s) that can be potentially disrupted in
AIP-negative FIPA families. A better knowledge of these susceptibility loci may
disclose modifier genes that are likely to play exacerbating or protective roles
in the phenotypic diversity of AIP-mutated families. Familial acromegaly may occur as a component of syndromes of multiple endocrine
neoplasia or as isolated familial somatotropinoma (IFS), which is included in
the spectrum of familial isolated pituitary adenoma (FIPA). We review the
pathogenesis of IFS, from the detection of loss of heterozygosity at chromosome
11q13 and establishment of linkage to this chromosome region to the description
of germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP)
gene. Approximately 40% of IFS families harbor an AIP mutation. In addition, we
summarize the clinical features of IFS families with AIP mutations: The adenomas
are diagnosed at a young age and are larger than in IFS patients without AIP
mutations or in sporadic somatotropinomas, indicating more aggressive disease. Multiple endocrine neoplasia type 1 (MEN1) and type 2 (MEN2) are major genetic
disorders carrying a high risk of endocrine tumor development. The mutated genes
were identified in 1993 (MEN2-RET) and 1997 (MEN1), enabling genetic testing and
functional studies. Genetic analysis has led to new clinical and therapeutic
strategies for MEN1/2 patients, and has improved our understanding of the
pathways underlying the development of such tumors, which occur in an autosomal
domit manner and with high penetrance. The MEN1 gene encodes menin, a protein
involved in many cell functions, such as transcription, genome stability, cell
cycling and apoptosis. The MEN1 gene has 10 exons, and its exhaustive analysis
in MEN1 patients helps guide their management. MEN2 is related to activating
missense mutations in the RET protooncogene, which encodes a tyrosine kinase
receptor (TKR). RET activation occurs upon autodimerization induced by the
binding of specific ligands belonging to glial cell-derived neurotrophic
factor-like family (GFL) proteins, regulated by coreceptors. The position of
missense mutations--in the extracellular or intracellular TK domains--influences
the aggressiveness of the most frequent maligcy, medullary thyroid carcinoma,
establishing a genotype-phenotype correlation. We also briefly describe the
genetic basis of three other inherited states predisposing individuals to
endocrine tumors, namely Carney's syndrome, hyperparathyroidism type 2 (HRPT2)
and familial isolated pituitary adenoma (FIPA), which are related to
inactivating mutations in the PRKAR1-alpha, HRPT2 and AIP genes, respectively. Mutations of the aryl hydrocarbon receptor interacting protein (AIP) gene are
associated with pituitary adenomas that usually occur as familial isolated
pituitary adenomas (FIPA). Detailed pathological and tumor genetic data on AIP
mutation-related pituitary adenomas are not sufficient. Non-identical twin
females presented as adolescents to the emergency department with severe
progressive headache caused by large pituitary macroadenomas require emergency
neurosurgery; one patient had incipient pituitary apoplexy. Post-surgically, the
patients were found to have silent somatotrope adenomas on pathological
examination. Furthermore, the light microscopic, immunohistochemical, and
electron microscopic studies demonstrated tumors of virtually identical
characteristics. The adenomas were accompanied by multiple areas of pituitary
hyperplasia, which stained positively for GH, indicating somatotrope
hyperplasia. Genetic analyses of the FIPA kindred revealed a novel E216X
mutation of the AIP gene, which was present in both the affected patients and
the unaffected father. Molecular analysis of surgical specimens revealed loss of
heterozygosity (LOH) in the adenoma but showed that LOH was not present in the
hyperplastic pituitary tissue from either patient. AIP immunostaining confirmed
normal staining in the hyperplastic tissue and decreased staining in the adenoma
in the tumors from both patients. These results demonstrate that patients with
AIP germline mutation can present with silent somatotrope pituitary adenomas.
The finding of somatotrope hyperplasia unaccompanied by AIP LOH suggests that
LOH at the AIP locus might be a late event in a potential progression from
hyperplastic to adenomatous tissue. Germline mutations in the aryl hydrocarbon receptor-interacting protein gene
(AIP) predispose to young-onset pituitary tumours, most often to GH- or
prolactin-secreting adenomas, and most of these patients belong to familial
isolated pituitary adenoma families. The molecular pathway initiated by the
loss-of-function AIP mutations leading to pituitary tumour formation is unknown.
AIP, a co-chaperone of heat-shock protein 90 and various nuclear receptors,
belongs to the family of tetratricopeptide repeat (TPR)-containing proteins. It
has three antiparallel α-helix motifs (TPR domains) that mediate the interaction
of AIP with most of its partners. In this review, we summarise the known
interactions of AIP described so far. The identification of AIP partners and the
understanding of how AIP interacts with these proteins might help to explain the
specific phenotype of the families with heterozygous AIP mutations, to gain
deeper insight into the pathological process of pituitary tumour formation and
to identify novel drug targets. Familial pituitary adenomas occur in multiple endocrine neoplasia type 1, Carney
complex, as well as in familial isolated pituitary adenoma syndrome. Familial
isolated pituitary adenoma syndrome is an autosomal domit disease with
incomplete penetrance. Pituitary adenomas occur in familial setting but without
any other specific tumors. In 20-40% of families with this syndrome, mutations
have been identified in the aryl hydrocarbon receptor interacting protein gene
while in the rest of the families the causative gene or genes have not been
identified. Families carrying aryl hydrocarbon receptor interacting protein gene
mutations have a distinct phenotype with younger age at diagnosis and a
predomice of somatotroph and lactotroph adenomas. Germline mutations of the
aryl hydrocarbon receptor interacting protein gene can be occasionally
identified in usually young-onset seemingly sporadic cases. Genetic and clinical
testing of relatives of patients with aryl hydrocarbon receptor interacting
protein gene mutations can lead to earlier diagnosis and treatment at an earlier
stage of the pituitary tumor. BACKGROUND: The paradox of pituitary tumours is that persistent growth is so
atypical. By definition, all pituitary microadenomas regain complete trophic
stability after an initial period of deregulated growth. Unlike tumours in many
other organ systems, concern about significant growth of macroadenoma remts
after debulking is minimal. Despite reports of a relatively high prevalence of
aneuploidy and clonal skewing in these tumours, prolonged efforts to implicate
classical proto-oncogene activation and tumour suppressor mutations have been of
limited success. No histological or molecular markers reliably predict
behaviour. To date, the number of molecular genetic factors unequivocally linked
to pituitary tumours can be counted on the fingers of one hand: (1) GNAS1
activation in acromegaly; (2) the MENIN and p27Kip1 (CDKN1B) mutations
associated with multiple endocrine neoplasia type 1; (3) mutations of PRKA1RA
with loss of 17q22-24 in Carney complex, and (4) aryl hydrocarbon receptor
interacting protein gene mutations in 15% of familial isolated pituitary
adenomas and 50% of familial isolated acromegaly. Together, these account for
only a small proportion (<5%) of sporadic pituitary macroadenomas.
CONCLUSION: In most instances, we still do not know what causes quantitative
aberrations in trophic behaviour. Familial isolated pituitary adenoma (FIPA) occurs in families and is unrelated
to multiple endocrine neoplasia type 1 and Carney complex. Mutations in AIP
account only for 15-25% of FIPA families. CDKN1B mutations cause MEN4 in which
affected patients can suffer from pituitary adenomas. With this study, we wanted
to assess whether mutations in CDKN1B occur among a large cohort of AIP
mutation-negative FIPA kindreds. Eighty-eight AIP mutation-negative FIPA
families were studied and 124 affected subjects underwent sequencing of CDKN1B.
Functional analysis of putative CDKN1B mutations was performed using in silico
and in vitro approaches. Germline CDKN1B analysis revealed two nucleotide
changes: c.286A>C (p.K96Q) and c.356T>C (p.I119T). In vitro, the K96Q change
decreased p27 affinity for Grb2 but did not segregate with pituitary adenoma in
the FIPA kindred. The I119T substitution occurred in a female patient with
acromegaly. p27(I119T) shows an abnormal migration pattern by SDS-PAGE. Three
variants (p.S56T, p.T142T, and c.605+36C>T) are likely nonpathogenic because In
vitro effects were not seen. In conclusion, two patients had germline sequence
changes in CDKN1B, which led to functional alterations in the encoded p27
proteins in vitro. Such rare CDKN1B variants may contribute to the development
of pituitary adenomas, but their low incidence and lack of clear segregation
with affected patients make CDKN1B sequencing unlikely to be of use in routine
genetic investigation of FIPA kindreds. However, further characterization of the
role of CDKN1B in pituitary tumorigenesis in these and other cases could help
clarify the clinicopathological profile of MEN4. Pituitary adenomas represent a group of functionally diverse neoplasms with
relatively high prevalence in the general population. Most occur sporadically,
but inherited genetic predisposing factors are increasingly recognized. Familial
isolated pituitary adenoma is a recently defined clinical entity, and is
characterized by hereditary presentation of pituitary adenomas in the absence of
clinical and genetic features of syndromic disease such as multiple endocrine
neoplasia type 1 and Carney complex. Familial isolated pituitary adenoma is
inherited in an autosomal domit manner and accounted for approximately 2-3%
of pituitary tumors in some series. Germline mutations in the aryl-hydrocarbon
interacting protein gene are identified in around 25% of familial isolated
pituitary adenoma kindreds. Pituitary adenomas with mutations of the
aryl-hydrocarbon interacting protein gene are predomitly somatotropinomas and
prolactinomas, but non-functioning adenomas, Cushing disease, and thyrotropinoma
may also occur. These tumors may present as macroadenomas in young patients and
are often relatively difficult to control. Furthermore, recent evidence
indicates that aryl-hydrocarbon interacting protein gene mutations occur in >10%
of patients with sporadic macroadenomas that occur before 30 years of age, and
in >20% of children with macroadenomas. Genetic screening for aryl-hydrocarbon
interacting protein gene mutations is warranted in selected high-risk patients
who may benefit from early recognition and follow-up. Familial isolated pituitary adenoma (FIPA) is an autosomal domit disease,
characterized by low penetrance, early-onset disease, more invasive tumor
growth, as well as somatotroph and lactotroph adenomas in most cases. It has
been indicated that the aryl hydrocarbon receptor interacting protein (AIP) gene
is a tumor suppressor gene. Many heterozygous mutations have been discovered in
AIP in about 20% of FIPA families. However, the exact molecular mechanism by
which its disfunction promotes tumorigenesis of pituitary is unclear. Pituitary adenomas are one of the most frequent intracranial tumors and occur
with a prevalence of approximately 1:1000 in the developed world. Pituitary
adenomas have a serious disease burden, and their management involves
neurosurgery, biological therapies, and radiotherapy. Early diagnosis of
pituitary tumors while they are smaller may help increase cure rates. Few
genetic predictors of pituitary adenoma development exist. Recent years have
seen two separate, complimentary advances in inherited pituitary tumor research.
The clinical condition of familial isolated pituitary adenomas (FIPA) has been
described, which encompasses the familial occurrence of isolated pituitary
adenomas outside of the setting of syndromic conditions like multiple endocrine
neoplasia type 1 and Carney complex. FIPA families comprise approximately 2% of
pituitary adenomas and represent a clinical entity with homogeneous or
heterogeneous pituitary adenoma types occurring within the same kindred. The
aryl hydrocarbon receptor interacting protein (AIP) gene has been identified as
causing a pituitary adenoma predisposition of variable penetrance that accounts
for 20% of FIPA families. Germline AIP mutations have been shown to associate
with the occurrence of large pituitary adenomas that occur at a young age,
predomitly in children/adolescents and young adults. AIP mutations are
usually associated with somatotropinomas, but prolactinomas, nonfunctioning
pituitary adenomas, Cushing disease, and other infrequent clinical adenoma types
can also occur. Gigantism is a particular feature of AIP mutations and occurs in
more than one third of affected somatotropinoma patients. Study of pituitary
adenoma patients with AIP mutations has demonstrated that these cases raise
clinical challenges to successful treatment. Extensive research on the biology
of AIP and new advances in mouse Aip knockout models demonstrate multiple
pathways by which AIP may contribute to tumorigenesis. This review assesses the
current clinical and therapeutic characteristics of more than 200 FIPA families
and addresses research findings among AIP mutation-bearing patients in different
populations with pituitary adenomas. CONTEXT: The molecular pathogenesis of primary hyperparathyroidism is still
largely unknown. The aryl hydrocarbon receptor interacting protein (AIP) gene
has a major role in the pathogenesis of familial isolated pituitary adenoma.
OBJECTIVE: We evaluated the involvement of the AIP gene in sporadic parathyroid
adenomas.
PATIENTS AND DESIGN: We performed direct sequencing and multiplex
ligation-dependent probe amplification analyses of the AIP gene in a large
series of sporadic parathyroid adenomas. Loss of heterozygosity (LOH) at the AIP
locus was studied, and aryl hydrocarbon receptor interacting protein
immunostaining was also performed. In addition, alterations in the MEN1 gene
were studied.
RESULTS: A somatic AIP mutation, substitution of arginine with glutamine at
codon 304 (R304Q), was identified in 2 of 132 tumors. The mutation was germline
in both cases despite the nonfamilial presentation. Heterozygous AIP large
deletions were detected in 29 cases including 1 of the 2 mutated tumors,
confirming a biallelic inactivation of the AIP gene. The AIP-mutated tumor with
LOH showed decreased AIP immunostaining compared with normal parathyroid. LOH at
the MEN1 locus, which often shared LOH at the AIP locus, was found in one third
of tumors. Somatic MEN1 mutations were found in the 1 of the 2 AIP-mutated
tumors and in 22 parathyroid adenomas. In addition, multiplex ligation-dependent
probe amplification analysis revealed 1 large deletion of the MEN1 gene in 1
patient.
CONCLUSIONS: The AIP gene is rarely involved in parathyroid adenomas, but the
germline nature of the mutations suggests that it might predispose to primary
hyperparathyroidism. MEN1 gene alterations occur in a substantial proportion of
sporadic parathyroid adenomas. Pituitary adenomas are common tumors of the adenohypophysis which can cause
considerable morbidity, due to excessive hormonal secretion or compression and
local invasion of surrounding structures. The vast majority of pituitary
adenomas occur sporadically. Altered gene expression is commonly detected but
somatic mutations, epigenetic changes and abnormal microRNAs have also been
described. Occurrence of GNAS mutations at a postzygotic stage lead to
McCune-Albright syndrome (MAS), a disease causing endocrine hyperfunction and
tumors in several organs, including the pituitary. Familial pituitary adenomas
occur as part of a syndrome affecting other organs, such as in MEN1 or Carney
complex, or occur with pituitary adenomas only as in familial isolated pituitary
adenoma (FIPA). FIPA, an autosomal-domit disease with variable penetrance, is
explained in 20% of patients by germline mutations in the tumor suppressor aryl
hydrocarbon receptor interacting protein(AIP), while no gene abnormality has
been identified to date in the majority of the FIPA families. AIP
mutation-positive patients have a characteristic clinical phenotype with usually
young- or childhood-onset growth hormone (GH) and/or prolactin (PRL)-secreting
adenomas and can be seen in cases with no apparent family history as well.
Understanding the tumorigenic process in AIP-positive and AIP-negative FIPA
patients could result in better diagnostic and treatment options for both
familial and sporadic cases. Aryl hydrocarbon receptor-interacting protein (AIP) is associated with 15-20% of
familial isolated pituitary adenomas and 50-80% of cases with AIP mutation
exhibit a somatotropinoma. Herein we report clinical characteristics of a large
family where AIP R304X variants have been identified. AIP mutation analysis was
performed on a large (n = 52) Turkish family across six generations. Sella MRIs
of 30 family members were obtained. Basal pituitary hormone levels were
evaluated in 13 family members harboring an AIP mutation. Thirteen of 52 family
members (25%) were found to have a heterozygous nonsense germline R304X mutation
in the AIP gene. Seven of the 13 mutation carriers (53.8%) had current or
previous history of pituitary adenoma. Of these 7 mutation carriers, all but one
had somatotropinoma/somatolactotropinoma (85.7% of the pituitary adenomas). Of
the 6 acromegaly patients with AIP mutation (F/M: 3/3) the mean age at diagnosis
of acromegaly was 32 ± 10.3 years while the mean age of symptom onset was 24.8 ±
9.9 years. Three of the six (50%) acromegaly cases with AIP mutation within the
family presented with a macroadenoma and none presented with gigantism.
Biochemical disease control was achieved in 66.6% (4/6) of the mutation carriers
with acromegaly after a mean follow-up period of 18.6 ± 17.6 years. Common
phenotypic characteristics of familial pituitary adenoma or somatotropinoma due
to AIP mutation vary between families or even between individuals within a
family. OBJECTIVE: The aryl hydrocarbon receptor interacting protein gene (AIP) is
associated with pituitary adenoma (PA). AIP has not been sequenced in East Asian
PA populations, so we performed this study in a Han Chinese cohort.
DESIGN: Our study included six familial PA pedigrees comprising 16 patients and
27 unaffected relatives, as well as 216 sporadic PA (SPA) patients and 100
unrelated healthy controls.
METHODS: AIP sequencing was carried out on genomic DNA isolated from blood
samples. Multiplex ligation-dependent probe amplification and microsatellite
marker analyses on DNA from the paired tumor tissues were performed for loss of
heterozygosity analysis.
RESULTS: We identified three common and four rare single nucleotide
polymorphisms (SNPs), one intron insertion, one novel synonymous variant, four
novel missense variants, and a reported nonsense mutation in three familial
isolated PA (FIPA) cases from the same family. Large genetic deletions were not
observed in the germline but were seen in the sporadic tumor DNA from three
missense variant carriers. The prevalence of AIP pathogenic variants in PA
patients here was low (3.88%), but was higher in somatotropinoma patients
(9.30%), especially in young adults (≤30 years) and pediatric (≥18 years)
paients (17.24% and 25.00% respectively). All AIP variant patients suffered from
macroadenomas. However, the AIP mutation rate in FIPA families was low in this
cohort (16.67%, 1/6 families).
CONCLUSION: AIP gene mutation may not be frequent in FIPA or SPA from the Han
Chinese population. AIP sequencing and long-term follow-up investigations should
be performed for young patients with large PAs and their families with PA
predisposition. CONTEXT: Germline AIP mutations usually cause young-onset acromegaly with low
penetrance in a subset of familial isolated pituitary adenoma families. We
describe our experience with a large family with R304* AIP mutation and discuss
some of the diagnostic dilemmas and management issues.
OBJECTIVE: The aim of the study was to identify and screen mutation carriers in
the family.
PATIENTS: Forty-three family members participated in the study.
SETTING: The study was performed in university hospitals.
OUTCOME: We conducted genetic and endocrine screening of family members.
RESULTS: We identified 18 carriers of the R304* mutation, three family members
with an AIP-variant A299V, and two family members who harbored both changes. One
of the two index cases presented with gigantism and pituitary apoplexy, the
other presented with young-onset acromegaly, and both had surgery and
radiotherapy. After genetic and clinical screening of the family, two R304*
carriers were diagnosed with acromegaly. They underwent transsphenoidal surgery
after a short period of somatostatin analog treatment. One of these two patients
is in remission; the other achieved successful pregcy despite suboptimal
control of acromegaly. One of the A299V carrier family members was previously
diagnosed with a microprolactinoma; we consider this case to be a phenocopy.
Height of the unaffected R304* carrier family members is not different compared
to noncarrier relatives.
CONCLUSIONS: Families with AIP mutations present particular problems such as the
occurrence of large invasive tumors, poor response to medical treatment,
difficulties with fertility and management of pregcy, and the finding of AIP
sequence variants of unknown significance. Because disease mostly develops at a
younger age and penetrance is low, the timing and duration of the follow-up of
carriers without overt disease requires further study. The psychological and
ficial impact of prolonged clinical screening must be considered. Excellent
relationships between the family, endocrinologists, and geneticists are
essential, and ideally these families should be managed in centers with
specialist expertise. Although the cause of familial isolated pituitary adenoma (FIPA) remains unknown
in many cases, germline mutations in the aryl hydrocarbon receptor-interacting
protein (AIP) gene were identified in approximately 20 % of families with FIPA.
We investigated the AIP gene mutation by a standard sequencing method in 12
members of a Japanese two-generation FIPA family, which includes 3 patients with
early-onset acromegaly. Multiplex ligation-dependent probe amplification
analysis in a tumor sample was attempted to examine the loss of heterozygosity
(LOH) in the locus. The effect of the detected mutation on cell proliferation
was investigated. A germline mutation of c.943C > T (p.Q315X) generating an AIP
protein with the C-terminal end deleted was found in the FIPA family. Biallelic
inactivation of AIP by a combination of the germline mutation and LOH at 11q13
was confirmed in the tumor. The nonsense mutation disrupted the ability to
inhibit cell proliferation. We conclude that p.Q315X mutation in the AIP gene is
a pathogenic variant and the C-terminal region of AIP plays an important role in
the predisposition to pituitary adenomas. |
which mutations of troponin C gene have been found to cause hypertrophic cardiomyopathy? | The following mutations of troponin C gene have been found to cause hypertrophic cardiomyopathy: L29Q; A8V; A31S; E134D; c.363dupG; A23Q; D145E and C84Y | We investigated structural and functional aspects of the first mutation in
TNNC1, coding for the calcium-binding subunit (cTnC) of cardiac troponin, which
was detected in a patient with hypertrophic cardiomyopathy [ Hoffmann B,
Schmidt-Traub H, Perrot A, Osterziel KJ & Gessner R (2001) Hum Mut17, 524]. This
mutation leads to a leucine-glutamine exchange at position 29 in the
nonfunctional calcium-binding site of cTnC. Interestingly, the mutation is
located in a putative interaction site for the nonphosphorylated N-terminal arm
of cardiac troponin I (cTnI) [ Finley NL, Abbott MB, Abusamhadneh E, Gaponenko
V, Dong W, Seabrook G, Howarth JW, Rana M, Solaro RJ, Cheung HC et al. (1999)
EJB Lett453, 107-112]. According to peptide array experiments, the
nonphosphorylated cTnI arm interacts with cTnC around L29. This interaction is
almost abolished by L29Q, as observed upon protein kinase A-dependent
phosphorylation of cTnI at serine 22 and serine 23 in wild-type troponin. With
CD spectroscopy, minor changes are observed in the backbone of Ca2+-free and
Ca2+-saturated cTnC upon the L29Q replacement. A small, but significant,
reduction in calcium sensitivity was detected upon measuring the Ca2+-dependent
actomyosin subfragment 1 (actoS1)-ATPase activity and the sliding velocity of
thin filaments. The maximum actoS1-ATPase activity, but not the maximum sliding
velocity, was significantly enhanced. In addition, we performed our
investigations at different levels of protein kinase A-dependent phosphorylation
of cTnI. The in vitro assays mainly showed that the Ca2+ sensitivity of the
actoS1-ATPase activity, and the mean sliding velocity of thin filaments, were no
longer affected by protein kinase A-dependent phosphorylation of cTnI owing to
the L29Q exchange in cTnC. The findings imply a hindered transduction of the
phosphorylation signal from cTnI to cTnC. The cardiac troponin C (cTnC) mutation, L29Q, has been found in a patient with
familial hypertrophic cardiomyopathy. We previously showed that L29, together
with neighboring residues, Asp2, Val28, and Gly30, plays an important role in
determining the Ca(2+) affinity of site II, the regulatory site of mammalian
cardiac troponin C (McTnC). Here we report on the Ca(2+) binding characteristics
of L29Q McTnC and D2N/V28I/L29Q/G30D McTnC (NIQD) utilizing the Phe(27) --> Trp
(F27W) substitution, allowing one to monitor Ca(2+) binding and release. We also
studied the effect of these mutants on Ca(2+) activation of force generation in
single mouse cardiac myocytes using cTnC replacement, together with sarcomere
length (SL) dependence. The Ca(2+)-binding affinity of site II of L29Q
McTnC(F27W) and NIQD McTnC(F27W) was approximately 1.3- and approximately
1.9-fold higher, respectively, than that of McTnC(F27W). The Ca(2+)
disassociation rate from site II of L29Q McTnC(F27W) and NIQD McTnC(F27W) was
not significantly different than that of control (McTnC(F27W)). However, the
rate of Ca(2+) binding to site II was higher in L29Q McTnC(F27W) and NIQD
McTnC(F27W) relative to control (approximately 1.5-fold and approximately
2.0-fold respectively). The Ca(2+) sensitivity of force generation was
significantly higher in myocytes reconstituted with L29Q McTnC (approximately
1.4-fold) and NIQD McTnC (approximately 2-fold) compared with those
reconstituted with McTnC. Interestingly, the change in Ca(2+) sensitivity of
force generation in response to an SL change (1.9, 2.1, and 2.3 mum) was
significantly reduced in myocytes containing L29Q McTnC or NIQD McTnC. These
results demonstrate that the L29Q mutation enhances the Ca(2+)-binding
characteristics of cTnC and that when incorporated into cardiac myocytes, this
mutant alters myocyte contractility. Hypertrophic Cardiomyopathy (HCM) is a common primary cardiac disorder defined
by a hypertrophied left ventricle, is one of the main causes of sudden death in
young athletes, and has been associated with mutations in most sarcomeric
proteins (tropomyosin, troponin T and I, and actin, etc.). Many of these
mutations appear to affect the functional properties of cardiac troponin C
(cTnC), i.e., by increasing the Ca(2+)-sensitivity of contraction, a hallmark of
HCM, yet surprisingly, prior to this report, cTnC had not been classified as a
HCM-susceptibility gene. In this study, we show that mutations occurring in the
human cTnC (HcTnC) gene (TNNC1) have the same prevalence (~0.4%) as well
established HCM-susceptibility genes that encode other sarcomeric proteins.
Comprehensive open reading frame/splice site mutation analysis of TNNC1
performed on 1025 unrelated HCM patients enrolled over the last 10 years
revealed novel missense mutations in TNNC1: A8V, C84Y, E134D, and D145E.
Functional studies with these recombit HcTnC HCM mutations showed increased
Ca(2+) sensitivity of force development (A8V, C84Y and D145E) and force recovery
(A8V and D145E). These results are consistent with the HCM functional phenotypes
seen with other sarcomeric-HCM mutations (E134D showed no changes in these
parameters). This is the largest cohort analysis of TNNC1 in HCM that details
the discovery of at least three novel HCM-associated mutations and more strongly
links TNNC1 to HCM along with functional evidence that supports a central role
for its involvement in the disease. This study may help to further define TNNC1
as an HCM-susceptibility gene, a classification that has already been
established for the other members of the troponin complex. Recently four new hypertrophic cardiomyopathy mutations in cardiac troponin C
(cTnC) (A8V, C84Y, E134D, and D145E) were reported, and their effects on the
Ca(2+) sensitivity of force development were evaluated (Landstrom, A. P.,
Parvatiyar, M. S., Pinto, J. R., Marquardt, M. L., Bos, J. M., Tester, D. J.,
Ommen, S. R., Potter, J. D., and Ackerman, M. J. (2008) J. Mol. Cell. Cardiol.
45, 281-288). We performed actomyosin ATPase and spectroscopic solution studies
to investigate the molecular properties of these mutations. Actomyosin ATPase
activity was measured as a function of [Ca(2+)] utilizing reconstituted thin
filaments (TFs) with 50% mutant and 50% wild type (WT) and 100% mutant cardiac
troponin (cTn) complexes: A8V, C84Y, and D145E increased the Ca(2+) sensitivity
with only A8V demonstrating lowered Ca(2+) sensitization at the 50% ratio when
compared with 100%; E134D was the same as WT at both ratios. Of these four
mutants, only D145E showed increased ATPase activation in the presence of
Ca(2+). None of the mutants affected ATPase inhibition or the binding of cTn to
the TF measured by co-sedimentation. Only D145E increased the Ca(2+) affinity of
site II measured by 2-(4'-(2''-iodoacetamido)phenyl)aminonaphthalene-6-sulfonic
acid fluorescence in isolated cTnC or the cTn complex. In the presence of the
TF, only A8V was further sensitized to Ca(2+). Circular dichroism measurements
in different metal-bound states of the isolated cTnCs showed changes in the
secondary structure of A8V, C84Y, and D145E, whereas E134D was the same as WT.
PyMol modeling of each cTnC mutant within the cTn complex revealed potential for
local changes in the tertiary structure of A8V, C84Y, and D145E. Our results
indicate that 1) three of the hypertrophic cardiomyopathy cTnC mutants increased
the Ca(2+) sensitivity of the myofilament; 2) the effects of the mutations on
the Ca(2+) affinity of isolated cTnC, cTn, and TF are not sufficient to explain
the large Ca(2+) sensitivity changes seen in reconstituted and fiber assays; and
3) changes in the secondary structure of the cTnC mutants may contribute to
modified protein-protein interactions along the sarcomere lattice disrupting the
coupling between the cross-bridge and Ca(2+) binding to cTnC. The role of the C-domain sites of cardiac troponin C in the modulation of the
calcium signal remains unclear. In this study, we investigated the effects of
hypertrophic cardiomyopathy-linked mutations A8V, E134D, and D145E in cardiac
troponin C on the properties of the C-domain sites. The A8V mutation had
essentially no effect on the calcium or magnesium binding properties of the
C-domain sites, while the mutation E134D moderately decreased calcium and
magnesium binding affinities. On the other hand, the D145E mutation affected
cooperative interactions between sites III and IV, significantly reducing the
calcium binding affinity of both sites. Binding of the anchoring region of
cardiac troponin I (corresponding to residues 34-71) to cardiac troponin C with
the D145E mutation was not able to recover normal calcium binding to the
C-domain. Experiments utilizing the fluorescent hydrophobic probe bis-ANS
suggest that the D145E mutation dramatically reduced the extent of
calcium-induced hydrophobic exposure by the C-domain. At high nonphysiological
calcium concentration, A8V, E134D, and D145E mutations minimally affected the
affinity of cardiac troponin C for the regulatory region of cardiac troponin I
(corresponding to residues 128-180). In contrast, at lower physiological calcium
concentration, the D145E mutation led to an approximately 8-fold decrease in the
affinity of cardiac troponin C for the regulatory region of cardiac troponin I.
Our results suggest that calcium binding properties of the C-domain sites might
be important for the proper regulatory function of cardiac troponin C. PurposeHypertrophic cardiomyopathy is the most common cause of sudden death in
young people, including trained athletes, and is caused by mutations in genes
encoding proteins of the cardiac sarcomere. Mutations in the Troponin C gene
(TNNC1) are a rare genetic cause of hypertrophic cardiomyopathy. We describe a
novel type of mutation (c.363dupG) in Troponin C, a rare form of hypertrophic
cardiomyopathy.
METHODS: A family in which a 19-year-old asymptomatic male died of sudden
cardiac death due to hypertrophic cardiomyopathy was genetically studied by
sequencing 17 genes associated with hypertrophic cardiomyopathy or its
phenocopies.
RESULTS: A c.363dupG mutation in Troponin C was identified, and tested across
the family.
CONCLUSIONS: We report the first frameshift mutation (c.363dupG or
p.Gln122AlafsX30) in Troponin C causing hypertrophic cardiomyopathy (and sudden
cardiac death) in a 19-year-old male, and have demonstrated that the mutation
segregates with hypertrophic cardiomyopathy within the family. The objective of this work was to investigate the effect of hypertrophic
cardiomyopathy-linked A8V and E134D mutations in cardiac troponin C (cTnC) on
the response of reconstituted thin filaments to calcium upon phosphorylation of
cardiac troponin I (cTnI) by protein kinase A. The phosphorylation of cTnI at
protein kinase A sites was mimicked by the S22D/S23D double mutation in cTnI.
Our results demonstrate that the A8V and E134D mutations had no effect on the
extent of calcium desensitization of reconstituted thin filaments induced by
cTnI pseudophosphorylation. However, the A8V mutation enhanced the effect of
cTnI pseudophosphorylation on the rate of dissociation of calcium from
reconstituted thin filaments and on the calcium dependence of actomyosin ATPase.
Consequently, while the A8V mutation still led to a slower rate of dissociation
of calcium from reconstituted thin filaments upon pseudophosphorylation of cTnI,
the ability of the A8V mutation to decrease the rate of calcium dissociation was
weakened. In addition, the ability of the A8V mutation to sensitize actomyosin
ATPase to calcium was weakened after cTnI was replaced by the phosphorylation
mimetic of cTnI. Consistent with the hypothesis that the E134D mutation is
benign, it exerted a minor to no effect on the rate of dissociation of calcium
from reconstituted thin filaments or on the calcium sensitivity of actomyosin
ATPase, regardless of the cTnI phosphorylation status. In conclusion, our study
enhances our understanding of how cardiomyopathy-linked cTnC mutations affect
the response of reconstituted thin filaments to calcium upon cTnI
phosphorylation. Defined as clinically unexplained hypertrophy of the left ventricle,
hypertrophic cardiomyopathy (HCM) is traditionally understood as a disease of
the cardiac sarcomere. Mutations in TNNC1-encoded cardiac troponin C (cTnC) are
a relatively rare cause of HCM. Here, we report clinical and functional
characterization of a novel TNNC1 mutation, A31S, identified in a pediatric HCM
proband with multiple episodes of ventricular fibrillation and aborted sudden
cardiac death. Diagnosed at age 5, the proband is family history-negative for
HCM or sudden cardiac death, suggesting a de novo mutation. TnC-extracted
cardiac skinned fibers were reconstituted with the cTnC-A31S mutant, which
increased Ca(2+) sensitivity with no effect on the maximal contractile force
generation. Reconstituted actomyosin ATPase assays with 50% cTnC-A31S:50%
cTnC-WT demonstrated Ca(2+) sensitivity that was intermediate between 100%
cTnC-A31S and 100% cTnC-WT, whereas the mutant increased the activation of the
actomyosin ATPase without affecting the inhibitory qualities of the ATPase. The
secondary structure of the cTnC mutant was evaluated by circular dichroism,
which did not indicate global changes in structure. Fluorescence studies
demonstrated increased Ca(2+) affinity in isolated cTnC, the troponin complex,
thin filament, and to a lesser degree, thin filament with myosin subfragment 1.
These results suggest that this mutation has a direct effect on the Ca(2+)
sensitivity of the myofilament, which may alter Ca(2+) handling and contribute
to the arrhythmogenesis observed in the proband. In summary, we report a novel
mutation in the TNNC1 gene that is associated with HCM pathogenesis and may
predispose to the pathogenesis of a fatal arrhythmogenic subtype of HCM. The Ca(2+) binding properties of the FHC-associated cardiac troponin C (cTnC)
mutation L29Q were examined in isolated cTnC, troponin complexes, reconstituted
thin filament preparations, and skinned cardiomyocytes. While higher Ca(2+)
binding affinity was apparent for the L29Q mutant in isolated cTnC, this
phenomenon was not observed in the cTn complex. At the level of the thin
filament in the presence of phosphomimetic TnI, L29Q cTnC further reduced the
Ca(2+) affinity by 27% in the steady-state measurement and increased the Ca(2+)
dissociation rate by 20% in the kinetic studies. Molecular dynamics simulations
suggest that L29Q destabilizes the conformation of cNTnC in the presence of
phosphomimetic cTnI and potentially modulates the Ca(2+) sensitivity due to the
changes of the opening/closing equilibrium of cNTnC. In the skinned
cardiomyocyte preparation, L29Q cTnC increased Ca(2+) sensitivity in a highly
sarcomere length (SL)-dependent manner. The well-established reduction of Ca(2+)
sensitivity by phosphomimetic cTnI was diminished by 68% in the presence of the
mutation and it also depressed the SL-dependent increase in myofilament Ca(2+)
sensitivity. This might result from its modified interaction with cTnI which
altered the feedback effects of cross-bridges on the L29Q cTnC-cTnI-Tm complex.
This study demonstrates that the L29Q mutation alters the contractility and the
functional effects of the phosphomimetic cTnI in both thin filament and single
skinned cardiomyocytes and importantly that this effect is highly sarcomere
length dependent. |
What is known about the effect of acupuncture in smoking cessation ? | Ear acupressure (EAP) and ear acupuncture have been used for smoking cessation, and some positive results have been reported.
Auricular (ear) acupressure has been purported to be beneficial in achieving smoking cessation in some studies, while in others has been deemed insignificant.
The combined acupuncture-education group showing the greatest effect from treatment. | BACKGROUND: Tobacco smoking is a major cause of preventable disease and
premature death. Physicians should play an active role in the control of smoking
by encouraging cessation and helping the smoker to choose the most suitable aid
to cessation.
AIM: To evaluate a simple, ear acupuncture treatment for the cessation of
smoking.
METHOD: Randomized, single-blind, placebo-controlled trial of 78 currently
smoking volunteers from the general public. Volunteers attended an acupuncture
clinic in a general practice setting and were given a single treatment of
electroacupuncture using two needles at either an active or a placebo site plus
self-retained ear seeds for two weeks. The major outcome measure was
biochemically validated total cessation of smoking at six months.
RESULTS: A total of 12.5% of the active treatment group compared with 0% of the
placebo group ceased smoking at six months (P = 0.055, 95% confidence interval
-0.033 to 0.323).
CONCLUSION: This simple ear electroacupuncture treatment was significantly more
effective in helping volunteers to quit smoking than placebo treatment. A double blind, randomized, placebo-controlled clinical study was conducted to
evaluate the efficacy of laser acupuncture treatment in adolescent smokers.
Three hundred and thirty adolescent smokers at the Smoking Cessation Clinic of
Child Guidance Clinic, Institute of Health, Singapore, were randomly assigned in
equal numbers to laser acupuncture treatment and sham acupuncture (control)
groups. The proportions of patients with complete smoking cessation after
completing treatment for four weeks were 21.9% in the treatment group and 21.4%
in the control group. At three months post-treatment, the rates for complete
cessation were 24.8% and 26.2%, respectively. Thus, there was no significant
difference in the rates of smoking cessation in the treatment and control
groups. OBJECTIVES: This study examined the effect of acupuncture alone and in
combination with education on smoking cessation and cigarette consumption.
METHODS: We prospectively studied 141 adults in a quasi-factorial design using
acupuncture, sham acupuncture, and education.
RESULTS: All groups showed significant reductions in smoking and posttreatment
cigarette consumption, with the combined acupuncture-education group showing the
greatest effect from treatment. The trend continued in follow-up; however,
significant differences were not maintained. Greater pack-year history (i.e. the
number of years smoking multiplied by baseline number of cigarettes smoked per
year, divided by 20 cigarettes per pack) negatively correlated with treatment
effect. Trend analysis suggested 20 pack-years as the cutoff point for this
correlation.
CONCLUSIONS: Acupuncture and education, alone and in combination, significantly
reduce smoking; however, combined they show a significantly greater effect, as
seen in subjects with a greater pack-year history. BACKGROUND: In complementary medicine literature studies on long-term
observation of one of its methods are rare.
OBJECTIVE: The present study is an evaluation of the smoking behavior of
patients treated with ear acupuncture for smoking cessation. Additionally we
investigated factors that favor or impede smoking cessation.
PATIENTS AND METHODS: 249 patients who had undergone ear acupuncture for smoking
cessation between 1985 and 1998 in a practice in Aarau (Switzerland) were asked
before the first treatment to fill in a form regarding their smoking behavior
and retrospectively in autumn 1998 a questionnaire regarding the success of
therapy. Ear acupuncture treatment consisted of 2 consultations at an interval
of 10 days. The responder rate was 53.8% (134 questionnaires were returned).
Finally the data of 126 persons could be evaluated.
RESULTS: The Kaplan Meier analysis of the abstinence time yielded a one-year
success rate of 41.1%. Men gave up smoking more easily than women. Start of
smoking as well as start of treatment between the age of 20 and 40 years were
favorable conditions for smoking cessation. People who had smoked 20 cigarettes
or more per day before treatment profited the best. For people who smoked as a
way of passing the time or because of tediousness it was easier to stop smoking
than for people smoking because of nervousness. People living in a non-smoker
household were able to stop smoking significantly easier than persons living in
a smoker household.
CONCLUSIONS: With a one-year success rate of 41.1% ear acupuncture is a
competitive alternative to orthodox medicine withdrawal methods. Acupuncture
treatment can be applied and adapted individually, furthermore it is economical
and without side effects. The use of alternative medicine for smoking cessation have been increasing
steadily in recent years. A series of clinical group studies was performed to
clarify the effect, outcome and success rate of an acupuncture treatment for
smoking cessation. This study was conducted for four weeks using 238 smoking
students at 2 high schools. The subjects were separated into two groups: 159
students were treated with acupuncture on the anti-smoking acupoints of the ear,
which is known to be effective for cessation of smoking (case group), and 79
students were treated at other sites of the ear (control group). The acupuncture
treatment was alternately administered at each side of the ears on a weekly
basis for 4 weeks. The smoking cessation success was only 1 case (0.6%) in the
case group and none in the control group after 4 weeks. The change in the taste
of tobacco and the intensity of the desire to smoke were not significantly
different between the case and control groups, but the case group showed a
tendency of reduction in the taste of tobacco and the intensity of the desire to
smoke. In addition, the reduction in cigarette consumption was not significant,
but the tendency of reduction in the study group was significant. It is believed
that the site of auricular acupuncture for smoking cessation is not important.
However, there was a significant tendency in terms of the reduction in cigarette
consumption, the taste of tobacco and the intensity of the desire to smoke in
the case group, indicating that auricular acupuncture in smoking cessation has
some effect. OBJECTIVES: This study aimed to develop an Internet-assisted smoking cessation
program accompanied with auricular acupressure, and compare the quit rate and
self-efficacy of youth smokers receiving auricular acupressure with and without
the Internet-assisted smoking cessation program.
DESIGN: A Website was constructed on IBM Websphere 5.0 and DB2 database using
HTML, Javascript, and JSP. A quasiexperimental research design was adopted.
Subjects were assigned nonrandomly to two groups. Group 1 received auricular
acupressure plus the Internet-assisted smoking cessation program, whereas group
2 received auricular acupressure only.
MEASUREMENTS: The data of demographic factors, serum cotinine, quitting rate,
nicotine dependence, and self-efficacy of subjects were collected before and
after a 4-week intervention.
RESULTS: After intervention, the quit rate was 15.78% in group 1 and 2.56% in
group 2. Nicotine dependence was significantly lowered in group 1, but remained
unchanged in group 2. The improvement of self-efficacy between groups 1 and 2
was significantly different.
CONCLUSIONS: The combination of auricular acupressure and Internet-assisted
smoking cessation program was more efficacious than auricular acupressure alone
in terms of quit rate. BACKGROUND: Tobacco smoking is responsible for human diseases of the lung,
heart, circulatory system and various kinds of cancers, and is a serious public
health problem worldwide. Acupuncture has been promoted as a treatment modality
for smoking cessation. However, its efficacy still remains controversial.
METHODS: We conducted a prospective, randomized, controlled trial using
auricular acupuncture for smoking cessation in 131 adults who wanted to stop
smoking. Thirteen subjects withdrew from the study and 118 subjects were
included in the final analyses (mean age, 53.7 +/- 16.8 years; 100 males, 18
females). The treatment group (n = 59) received auricular acupuncture in Shen
Men, Sympathetic, Mouth and Lung points for 8 weeks. The control group (n = 59)
received sham acupuncture in non-smoking-cessation-related auricular acupoints
(Knee, Elbow, Shoulder and Eye points). The enrolled subjects were then followed
monthly for 6 months after stopping the acupuncture treatment.
RESULTS: Between both groups before acupuncture treatment, there was no
significant difference with regard to gender, mean age, education level, and
mean values for the age at which smoking started, smoking duration, daily number
of cigarettes smoked and nicotine dependent score. At the end of treatment,
cigarette consumption had significantly decreased in both groups, but only the
treatment group showed a significant decrease in the nicotine withdrawal symptom
score. Smoking cessation rate showed no significant difference between the
treatment group (27.1%) and the control group (20.3%) at the end of treatment.
There was also no significant difference in the smoking cessation rate between
the treatment group (16.6%) and the control group (12.1%) at the end of
follow-up. There were no major side effects of auricular acupuncture in both
groups.
CONCLUSION: Our results showed that auricular acupuncture did not have a better
efficacy in smoking cessation compared to sham acupuncture. Combined acupuncture
with behavior counseling or with nicotine replacement therapy should be used in
further smoking cessation trials to enhance the success rate of smoking
cessation. OBJECTIVE: To observe therapeutic effect of acupuncture combined with auricular
point sticking and pressing for smoking cessation.
METHODS: Body acupoints for acupuncture, Jieyan (two horizontal fingers above
styloid process of radius), Shenmen (HT 7), Zhongwan (CV 12), Zusanli (ST 36),
Sanyingjiao (SP 6). Main ear acupoints: Kou (mouth), Fei (lung), Shenmen, and
adjuvant ear points: Shenshangxian (adrenal gland), Wei (stomach), Xin (heart),
Neifenmi (endocrine), Qiguan (trachea), Gan (liver). The treatment was given
once daily, 6 sessions constituting one course, and the therapeutic effects were
observed after 4 courses.
RESULTS: Thirty-six were cured, 12 cases were effective, 5 cases were
ineffective.
CONCLUSION: Acupuncture combined with auricular point sticking and pressing has
reliable therapeutic effect for smoking cessation, but it is needed that the
patient cooperates actively and has the will of smoking cessation, so as to
avoid re-taking smoking. BACKGROUND: Tobacco smoking is still a worldwide health risk. Current
pharmacotherapies have at best, a success rate of no more than 50%. Auricular
(ear) acupressure has been purported to be beneficial in achieving smoking
cessation in some studies, while in others has been deemed insignificant. We
hereby describe the protocol for a three-arm randomised controlled trial to
examine the possible benefits of self-administered acupressure for smoking
cessation.
METHODS: Sixty consenting participants with confirmed habit of tobacco smoking
will be recruited and randomized into three arms to receive either auricular
acupressure at five true acupoints (NADA protocol), auricular acupressure at
five sham points, or no auricular acupressure at all. Participants having
auricular acupressure will exert firm pressure to each acupoint bilaterally via
the bead in the attached plasters whenever they feel the urge to smoke. The
treatment phase will last for six weeks during which all participants will be
assessed weekly to review their smoking log, state of abstinence, end-exhalation
carbon monoxide levels and possible adverse effects including withdrawal
reactions and stress levels. At any time, a successful quit date will be defined
with continuous abstinence for the following consecutive 7 days. From then on,
participants will be evaluated individually for continuous abstinence rate
(CAR), end-exhalation carbon monoxide levels and adverse effects of stress and
withdrawal at specified intervals up to 26 weeks. Expectancy of treatment will
be assessed with a four-item Borkovec and Nau self-assessment credibility scale
during and after intervention.
DISCUSSION: We incorporate validated outcome measures of smoking cessation into
our randomised controlled trial design with the objectives to evaluate the
feasibility and possible benefits of self-administered auricular acupressure as
a non-invasive alternative to pharmacotherapy for smoking cessation.
TRIAL REGISTRATION: ClinicalTrials.gov: NCT01389622 (registered Jul 7 2011). BACKGROUND: Smoking is the largest preventable cause of death and disease
worldwide but smokers often fail to quit due to nicotine withdrawal symptoms.
Current available pharmaceutical therapies may assist with smoking cessation but
may have side effects. Ear acupressure (EAP) and ear acupuncture have been used
for smoking cessation, and some positive results have been reported. The aim of
the study is to assess the efficacy and safety of EAP in assisting individuals
to quit smoking and/or support them in the management of nicotine withdrawal
symptoms.
METHODS: This study will be a randomised, single-blind, sham-controlled study
conducted at RMIT University in Melbourne, Australia. Adult smokers will be
randomly assigned to receive EAP specifically for smoking cessation or
nonspecific EAP treatments. After a 2-week run-in, participants will be treated
once a week for 8 weeks and followed up for 12 weeks. The primary outcome
measures will be 7 day point-prevalence cessation rate by self-report validated
by expired carbon monoxide and nicotine withdrawal symptoms measured by the Mood
and Physical Symptoms Score questionnaire. Secondary outcomes will be
self-reported usage of nicotine replacement therapies, cigarette consumption,
body weight change and quality of life. The safety end point will be
self-reported adverse events associated with EAP. Intention-to-treat analysis
will be applied.
DISCUSSION: Findings from this study will determine if this EAP intervention
alone can be an effective and safe therapy to assist with smoking cessation and
the management of nicotine withdrawal symptoms. |
Which post-translational histone modifications are characteristic of constitutive heterochromatin? | H3K9me3 is the major marker of constitutive heterochromatin. Other histone methylation marks usually found in constitutive heterochromatin, are H4K20me3 and H3K79me3. Classical histone modifications associated with heterochromatin include H3K9me2, H3K27me1 and H3K27me2. Histone H3 trimethylation at lysine 36 is associated with constitutive and facultative heterochromatin. H3S10 phosphorylation marks constitutive heterochromatin during interphase in early mouse embryos until the 4-cell stage | Histone methylation was first described more than 35 years ago, but its role has
remained enigmatic. Proposed functions range from transcriptional regulation to
the higher-order packaging of chromatin in preparation for mitotic condensation.
Histone methylation can occur on Arg or Lys residues, with an exquisite site
selectivity for Lys methylation at specific positions in the N-termini of
histones H3 and H4. Thus, Lys methylation joins acetylation and phosphorylation
as a third component of a 'histone code' that modifies the underlying chromatin
structure of the genetic information. Notably, in contrast to acetylation and
phosphorylation, Lys methylation appears to be a relatively stable histone
modification, thereby providing an ideal epigenetic mark for more long-term
maintece of chromatin states. The recent discovery of the first histone Lys
methyltransferase has allowed the identification of a molecular mechanism in
which the specific methylation of histone H3 at Lys9 generates a binding site
for heterochromatin-associated proteins. These findings have broad implications
for the overall functional organization of chromosome structure at constitutive
heterochromatin (e.g. centromeres) and for chromatin-dependent inheritance of
gene expression patterns. This review discusses how understanding this
methylation system should address some of the long-standing mysteries of
heterochromatin. Post-translational modifications of histone amino termini are an important
regulatory mechanism that induce transitions in chromatin structure, thereby
contributing to epigenetic gene control and the assembly of specialized
chromosomal subdomains. Methylation of histone H3 at lysine 9 (H3-Lys9) by
site-specific histone methyltransferases (Suv39h HMTases) marks constitutive
heterochromatin. Here, we show that H3-Lys9 methylation also occurs in
facultative heterochromatin of the inactive X chromosome (Xi) in female mammals.
H3-Lys9 methylation is retained through mitosis, indicating that it might
provide an epigenetic imprint for the maintece of the inactive state.
Disruption of the two mouse Suv39h HMTases abolishes H3-Lys9 methylation of
constitutive heterochromatin but not that of the Xi. In addition, HP1 proteins,
which normally associate with heterochromatin, do not accumulate with the Xi.
These observations suggest the existence of an Suv39h-HP1-independent pathway
regulating H3-Lys9 methylation of facultative heterochromatin. In eukaryotes, histone methylation is an epigenetic mechanism associated with a
variety of functions related to gene regulation or genomic stability. Recently
analyzed H3K9 methyltransferases (HMTases) as SUV39H1, Clr4p, DIM-5, Su(var)3-9
or SUVH2 are responsible for the establishment of histone H3 lysine 9
methylation (H3K9me), which is intimately connected with heterochromatinization.
In this review, available data will be evaluated concerning (1) the phylogenetic
distribution of H3K9me as heterochromatin-specific histone modification and its
evolutionary stability in relation to other epigenetic marks, (2) known families
of H3K9 methyltransferases, (3) their responsibility for the formation of
constitutive heterochromatin and (4) the evolution of Su(var)3-9-like and
SUVH-like H3K9 methyltransferases. Compilation and parsimony analysis reveal
that histone H3K9 methylation is, next to histone deacetylation, the
evolutionary most stable heterochromatic mark, which is established by at least
two subfamilies of specialized heterochromatic HMTases in almost all studied
eukaryotes. Centromeres are the fragments of DNA that are responsible for proper chromosome
segregation. They consist of centromeric chromatin surrounded by blocks of
pericentric heterochromatin, playing an important role in centromere function.
In somatic cells, the pericentric domains have a specific pattern of epigenetic
modifications of core histones and contain specific pericentric proteins. These
features are probably more important for the centromere function than the
sequence of the centromeric DNA itself. In somatic cells, the HP1alpha and
HP1beta proteins are indispensable for constitutive heterochromatin formation
and maintece. We have analyzed the localization of these proteins in the
primordial, growing, fully-grown, and maturing mouse oocytes. Additionally, we
have analyzed post-translational modifications of histone H3, which can
influence HP1alpha and HP1beta association with the heterochromatin. We showed
that the regions of constitutive heterochromatin have a distinct pattern of
histone H3 acetylation and di-, and trimethylation of its lysine 9. We
demonstrated that HP1beta protein was present in pericentric chromatin domains
in primordial oocytes, growing (transcriptionally active) oocytes, and in
fully-grown oocytes, and was released to the cytoplasm after germinal vesicle
breakdown. In contrast, the HP1alpha was never detected in primordial oocytes,
was first detected in pericentric heterochromatin in growing oocytes,
dissociated from pericentric heterochromatin in fully-grown oocytes, and it was
never detected in maturing oocytes. The presence of HP1alpha and HP1beta
proteins on the heterochromatin of transcriptionally active oocytes and their
absence in transcriptionally silent oocytes suggest that they are necessary for
the repression of RNA synthesis in heterochromatin domains of transcribing
oocytes. Herpesvirus latency is generally thought to be governed by epigenetic
modifications, but the dynamics of viral chromatin at early timepoints of latent
infection are poorly understood. Here, we report a comprehensive spatial and
temporal analysis of DNA methylation and histone modifications during latent
infection with Kaposi Sarcoma-associated herpesvirus (KSHV), the etiologic agent
of Kaposi Sarcoma and primary effusion lymphoma (PEL). By use of high resolution
tiling microarrays in conjunction with immunoprecipitation of methylated DNA
(MeDIP) or modified histones (chromatin IP, ChIP), our study revealed highly
distinct landscapes of epigenetic modifications associated with latent KSHV
infection in several tumor-derived cell lines as well as de novo infected
endothelial cells. We find that KSHV genomes are subject to profound methylation
at CpG dinucleotides, leading to the establishment of characteristic global DNA
methylation patterns. However, such patterns evolve slowly and thus are unlikely
to control early latency. In contrast, we observed that latency-specific histone
modification patterns were rapidly established upon a de novo infection. Our
analysis furthermore demonstrates that such patterns are not characterized by
the absence of activating histone modifications, as H3K9/K14-ac and H3K4-me3
marks were prominently detected at several loci, including the promoter of the
lytic cycle transactivator Rta. While these regions were furthermore largely
devoid of the constitutive heterochromatin marker H3K9-me3, we observed rapid
and widespread deposition of H3K27-me3 across latent KSHV genomes, a bivalent
modification which is able to repress transcription in spite of the simultaneous
presence of activating marks. Our findings suggest that the modification
patterns identified here induce a poised state of repression during viral
latency, which can be rapidly reversed once the lytic cycle is induced. X chromosome inactivation (XCI) is the transcriptional silencing of one X in
female mammals, balancing expression of X genes between females (XX) and males
(XY). In placental mammals non-coding XIST RNA triggers silencing of one X (Xi)
and recruits a characteristic suite of epigenetic modifications, including the
histone mark H3K27me3. In marsupials, where XIST is missing, H3K27me3
association seems to have different degrees of stability, depending on
cell-types and species. However, the complete suite of histone marks associated
with the Xi and their stability throughout cell cycle remain a mystery, as does
the evolution of an ancient mammal XCI system. Our extensive immunofluorescence
analysis (using antibodies against specific histone modifications) in nuclei of
mammals distantly related to human and mouse, revealed a general absence from
the mammalian Xi territory of transcription machinery and histone modifications
associated with active chromatin. Specific repressive modifications associated
with XCI in human and mouse were also observed in elephant (a distantly related
placental mammal), as was accumulation of XIST RNA. However, in two marsupial
species the Xi either lacked these modifications (H4K20me1), or they were
restricted to specific windows of the cell cycle (H3K27me3, H3K9me2).
Surprisingly, the marsupial Xi was stably enriched for modifications associated
with constitutive heterochromatin in all eukaryotes (H4K20me3, H3K9me3). We
propose that marsupial XCI is comparable to a system that evolved in the common
therian (marsupial and placental) ancestor. Silent chromatin of the early
inactive X was exapted from neighbouring constitutive heterochromatin and, in
early placental evolution, was augmented by the rise of XIST and the stable
recruitment of specific histone modifications now classically associated with
XCI. The mammalian genome contains numerous regions known as facultative
heterochromatin, which contribute to transcriptional silencing during
development and cell differentiation. We have analyzed the pattern of histone
modifications associated with facultative heterochromatin within the mouse
imprinted Snurf-Snrpn cluster, which is homologous to the human Prader-Willi
syndrome genomic region. We show here that the maternally inherited Snurf-Snrpn
3-Mb region, which is silenced by a potent transcription repressive mechanism,
is uniformly enriched in histone methylation marks usually found in constitutive
heterochromatin, such as H4K20me3, H3K9me3, and H3K79me3. Strikingly, we found
that trimethylated histone H3 at lysine 36 (H3K36me3), which was previously
identified as a hallmark of actively transcribed regions, is deposited onto the
silenced, maternally contributed 3-Mb imprinted region. We show that H3K36me3
deposition within this large heterochromatin domain does not correlate with
transcription events, suggesting the existence of an alternative pathway for the
deposition of this histone modification. In addition, we demonstrate that
H3K36me3 is markedly enriched at the level of pericentromeric heterochromatin in
mouse embryonic stem cells and fibroblasts. This result indicates that H3K36me3
is associated with both facultative and constitutive heterochromatin. Our data
suggest that H3K36me3 function is not restricted to actively transcribed regions
only and may contribute to the composition of heterochromatin, in combination
with other histone modifications. Non-coding transcription can trigger histone post-translational modifications
forming specialized chromatin. In fission yeast, heterochromatin formation
requires RNAi and the histone H3K9 methyltransferase complex CLRC, composed of
Clr4, Raf1, Raf2, Cul4, and Rik1. CLRC mediates H3K9 methylation and siRNA
production; it also displays E3-ubiquitin ligase activity in vitro. DCAFs act as
substrate receptors for E3 ligases and may couple ubiquitination with histone
methylation. Here, structural alignment and mutation of signature WDxR motifs in
Raf1 indicate that it is a DCAF for CLRC. We demonstrate that Raf1 promotes H3K9
methylation and siRNA amplification via two distinct, separable functions. The
association of the DCAF Raf1 with Cul4-Rik1 is critical for H3K9 methylation,
but dispensable for processing of centromeric transcripts into siRNAs. Thus the
association of a DCAF, Raf1, with its adaptor, Rik1, is required for histone
methylation and to allow RNAi to signal to chromatin. Phosphorylation of histone H3 at Ser10 (H3S10P) has been linked to a variety of
cellular processes, such as chromosome condensation and gene
activation/silencing. Remarkably, in mammalian somatic cells, H3S10P initiates
in the pericentromeric heterochromatin during the late G2 phase, and
phosphorylation spreads throughout the chromosomes arms in prophase, being
maintained until the onset of anaphase when it gets dephosphorylated.
Considerable studies have been carried out about H3S10P in different organisms;
however, there is little information about this histone modification in
mammalian embryos. We hypothesized that this epigenetic modification could also
be a marker of pericentromeric heterochromatin in preimplantation embryos. We
therefore followed the H3S10P distribution pattern in the G1/S and G2 phases
through the entire preimplantation development in in vivo mouse embryos. We paid
special attention to its localization relative to another pericentromeric
heterochromatin marker, HP1β and performed immunoFISH using specific
pericentromeric heterochromatin probes. Our results indicate that H3S10P
presents a remarkable distribution pattern in preimplantation mouse embryos
until the 4-cell stage and is a better marker of pericentromeric heterochromatin
than HP1β. After the 8-cell stage, H3S10P kinetic is more similar to the somatic
one, initiating during G2 in chromocenters and disappearing upon telophase.
Based on these findings, we believe that H3S10P is a good marker of
pericentromeric heterochromatin, especially in the late 1- and 2-cell stages as
it labels both parental genomes and that it can be used to further investigate
epigenetic regulation and heterochromatin mechanisms in early preimplantation
embryos. |
GV1001 vaccine targets which enzyme? | GV1001 is a 16-amino-acid vaccine peptide derived from the human telomerase reverse transcriptase sequence. It has been developed as a vaccine against various cancers. | Pancreatic cancer has a very high mortality rate and affects approximately
230,000 individuals worldwide. Gemcitabine has become established as the
standard therapy for advanced pancreatic cancer; however, the survival advantage
is small. Adjuvant chemotherapy using either 5-fluorouracil or gemcitabine is
now established in pancreatic cancer as an alternative therapy. Combinations of
gemcitabine with either platin agents or capecitabine may be advantageous.
Anti-EGFR and anti-VEGF agents have been unsuccessful but multiple tyrosine
kinase inhibitors are under investigation. Of the increasing number of
immunological agents, the GV1001 antitelomerase vaccine holds some interest.
Targeted agents against important mitogenic pathways, including MEK/ERK, Src,
PI3K/Akt, mTOR, Hedgehog and NF-kappaB, as well as agents targeting histone
deacetylase, poly(ADP-ribose) polymerase, heat shock protein 90 and other agents
such as beta-lapachone, hold considerable interest for further development.
However, the probability of individual success is low. BACKGROUND: There is currently no curative therapy for cutaneous T cell lymphoma
(CTCL). New therapies are therefore needed. Telomerase, the enzyme that allows
for unrestricted cell divisions of cancer cells, is a promising target for
cancer therapy. The telomerase-specific peptide vaccination GV1001 has shown
promising results in previous studies. Since telomerase is expressed in
maligt cells of CTCL, GV1001 vaccination in CTCL is a promising new
therapeutic approach.
OBJECTIVE: We sought to investigate the efficacy of GV1001 vaccination in CTCL
patients and characterize the induced immune response.
METHODS: Six CTCL patients were vaccinated with the GV-peptide using
granulocyte/macrophage colony-stimulating factor as adjuvant. Objective clinical
response and the T cell response were assessed.
RESULTS: None of the patients demonstrated objective clinical response to the
vaccination whereas one patient showed disease progression. 1/6 patients
acquired a GV1001-specifc T cell response with a Th1 cytokine profile and
expression of skin-homing receptors. This hTERT-specific T cell response was not
associated with beneficial modulation of the tumor-infiltrating leukocytes.
Furthermore, removal of regulatory T cells did not enhance responsiveness to
GV1001 in vitro in any of the patients analyzed.
CONCLUSIONS: Our results suggest that the GV1001 vaccination is not effective in
CTCL patients and disease progression in 1/6 patients raises concerns about its
safety. By analyzing skin-homing properties of GV1001-specific T cells and the
involvement of regulatory T cells we nevertheless provide insight into
vaccine-induced immune responses which may help to improve vaccine strategies in
CTCL. PURPOSE: The study is a proof-of-principle trial evaluating toxicity, immune
response, and clinical response in melanoma patients after combined therapy with
temozolomide and the telomerase peptide vaccine GV1001. Our previous GV1001
trials showed immune responses in approximately 60% of lung or pancreatic cancer
patients.
EXPERIMENTAL DESIGN: Twenty-five subjects with advanced stage IV melanoma (M1B
or M1C) received concomitant temozolomide and GV1001. Temozolomide was
administered 200 mg/m² orally for 5 days every fourth week, and GV1001 as eight
injections over 11 weeks. Immune response was evaluated by delayed type
hypersensitivity, T-cell proliferation, and cytokine assays. The immunologic
responders continued monthly vaccination.
RESULTS: The treatment was well tolerated. A GV1001-specific immune response was
shown in 18 of 23 evaluated subjects (78%). Patients developing long-term T-cell
memory survived more than those rapidly losing their responses. The immune
response exhibited several characteristics of possible clinical significance
including high IFNγ/IL-10 ratios, polyfunctional cytokine profiles, and
recognition of naturally processed antigens. Survival compared favorably with
matched controls from a benchmark meta-analysis (1 year: 44% vs. 24%, 2 years:
16% vs. 6.6%). The clinical responses developed gradually over years, contrary
to what is expected from chemotherapy. Five patients developed partial tumor
regression and six more recorded stable disease. One patient has no remaining
disease on fluorodeoxyglucose positron emission tomography scans after 5 years.
CONCLUSIONS: The immunologic response rate is considerable compared with
previous GV1001 trials without concomitant chemotherapy, although low toxicity
is retained. The results warrant further studies of GV1001/temozolomide
treatment and support the general concept of combining cancer vaccination with
chemotherapy. Telomeres are protective caps at the ends of human chromosomes. Telomeres
shorten with each successive cell division in normal human cells whereas, in
tumors, they are continuously elongated by human telomerase reverse
transcriptase (hTERT). Telomerase is overexpressed in 80-95% of cancers and is
present in very low levels or is almost undetectable in normal cells. Because
telomerase plays a pivotal role in cancer cell growth it may serve as an ideal
target for anticancer therapeutics. Inhibition of telomerase may lead to a
decrease of telomere length resulting in cell senescence and apoptosis in
telomerase positive tumors. Several strategies of telomerase inhibition are
reviewed, including small molecule inhibitors, antisense oligonucleotides,
immunotherapies and gene therapies, targeting the hTERT or the ribonucleoprotein
subunit hTER. G-quadruplex stabilizers, tankyrase and HSP90 inhibitors targeting
telomere and telomerase assembly, and T-oligo approach are also covered. Based
on this review, the most promising current telomerase targeting therapeutics are
the antisense oligonucleotide inhibitor GRN163L and immunotherapies that use
dendritic cells (GRVAC1), hTERT peptide (GV1001) or cryptic peptides (Vx-001).
Most of these agents have entered phase I and II clinical trials in patients
with various tumors, and have shown good response rates as evidenced by a
reduction in tumor cell growth, increased overall disease survival, disease
stabilization in advanced staged tumors and complete/partial responses. Most
therapeutics have shown to be more effective when used in combination with
standard therapies, resulting in concomitant telomere shortening and tumor mass
shrinkage, as well as preventing tumor relapse and resistance to single agent
therapy. A reverse-transcriptase-subunit of telomerase (hTERT) derived peptide, GV1001,
has been developed as a vaccine against various cancers. Previously, we have
shown that GV1001 interacts with heat shock proteins (HSPs) and penetrates cell
membranes to be localized in the cytoplasm. In this study, we have found that
GV1001 lowered the level of intracellular and surface HSPs of various cancer
cells. In hypoxic conditions, GV1001 treatment of cancer cells resulted in
decreases of HSP90, HSP70, and HIF-1α. Subsequently, proliferation of cancer
cells and synthesis of VEGF were significantly reduced by treatment using GV1001
in hypoxic conditions. In an experiment using a nude mouse xenograft model,
GV1001 exerted a similar tumor suppressive effect, further confirming its
anti-tumor efficacy. Higher apoptotic cell death, reduced proliferation of
cells, and fewer blood vessels were observed in GV1001-treated tumors compared
to control. In addition, significant reduction of Tie2+ CD11b+ monocytes, which
were recruited by VEGF from tumor cells and play a critical role in
angiogenesis, was observed in GV1001-treated tumors. Collectively, the results
suggest that GV1001 possesses potential therapeutic efficacy in addition to its
ability to induce anti-cancer immune responses by suppressing both HSP70 and
HSP90. GV1001 is a 16-amino-acid vaccine peptide derived from the human telomerase
reverse transcriptase sequence. We investigated the effects of GV1001 against
β-amyloid (Aβ) oligomer-induced neurotoxicity in rat neural stem cells (NSCs).
Primary culture NSCs were treated with several concentrations of GV1001 and/or
Aβ₂₅₋₃₅ oligomer for 48 hours. GV1001 protected NSCs against the Aβ₂₅₋₃₅
oligomer in a concentration-dependent manner. Aβ₂₅₋₃₅ concentration dependently
decreased viability, proliferation, and mobilization of NSCs and GV1001
treatment restored the cells to wild-type levels. Aβ₂₅₋₃₅ increased free radical
levels in rat NSCs while combined treatment with GV1001 significantly reduced
these levels. In addition, GV1001 treatment of Aβ₂₅₋₃₅-injured NSCs increased
the expression level of survival-related proteins, including
mitochondria-associated survival proteins, and decreased the levels of death and
inflammation-related proteins, including mitochondria-associated death proteins.
Together, these results suggest that GV1001 possesses neuroprotective effects
against Aβ₂₅₋₃₅ oligomer in NSCs and that these effects are mediated through
mimicking the extra-telomeric functions of human telomerase reverse
transcriptase, including the induction of cellular proliferation, anti-apoptotic
effects, mitochondrial stabilization, and anti-aging and anti-oxidant effects. BACKGROUND: Ischemia reperfusion injury (IRI) is a common complication after
kidney transplantation. Peptide GV1001 is a peptide vaccine representing a
16-amino acid human telomerase reverse transcriptase sequence, which has been
reported to possess potential antineoplastic and anti-inflammatory activity.
This study aimed to investigate the potential effects of peptide GV1001 on renal
IRI.
METHODS: Peptide GV1001 was subcutaneously administered to C57BL6/J mice 30
minutes before and 12 hours after bilateral IRI. Sham operation and
phosphate-buffered saline (PBS) injection were used as controls. Blood and renal
tissues were harvested at 1 day after IRI.
RESULTS: Peptide GV1001 treatment significantly attenuated renal functional
deterioration after IRI (peptide GV1001 group vs PBS group; blood urea nitrogen,
P < .05; creatinine, P < .05). Peptide GV1001 treatment also attenuated renal
tissue injury (tubular injury score; the peptide GV1001 group vs PBS group; P <
.001). Renal apoptosis was also lower in the peptide GV1001 group.
Immunohistochemical studies showed that IRI increased perirenal infiltration of
both neutrophils and macrophages, and that peptide GV1001 significantly
attenuated this process. Expression of interleukin-6 and monocyte chemotactic
protein-1 was significantly reduced by peptide GV1001 treatment.
CONCLUSIONS: Peptide GV1001 ameliorates acute renal IRI by reducing inflammation
and apoptosis; therefore, it is promising as a potential therapeutic agent for
renal IRI. The mechanisms of protection should be explored in further studies. Telomerase is expressed in 85-90 % of pancreatic adenocarcinomas and might be a
target for active cancer immunotherapy. A study was conducted to investigate
safety and immunogenicity in non-resectable pancreatic carcinoma patients using
a 16-amino acid telomerase peptide (GV1001) for vaccination in combination with
GM-CSF and gemcitabine as first line treatment. Three different vaccine
treatment schedules were used; [A (n=6), B (n=6) and C (n=5)]. Groups A/B
received GV1001, GM-CSF and gemcitabine concurrently. Group C received initially
GV1001 and GM-CSF while gemcitabine was added at disease progression. Group D
(n=4) was treated with gemcitabine alone. Adverse events (AE) related to
vaccination were mild (grades I-II). Grade III AEs were few and transient. An
induced GV 1001‑specific immune response was defined as an increase ≥2 above the
baseline value in one of the assays (DTH, proliferation, ELISPOT and cytokine
secretion assays, respectively). A telomerase‑specific immune response was noted
in 4/6 patients in group A, 4/6 patients in group B and 2/5 patients in group C.
An induced ras‑specific immune response (antigenic spreading) was seen in 5 of
the 17 patients. The cytokine pattern was that of a Th1-like profile. A
treatment induced telomerase or ras response was also noted in group D. All
responses were weak and transient. A significant decrease in regulatory T-cells
over time was noted in patients in groups A and B (p<0.05). Telomerase
vaccination (GV1001) in combination with chemotherapy appeared to be safe but
the immune responses were weak and transient. Measures have to be taken to
optimize immune responses of GV1001 for it to be considered of clinical
interest. BACKGROUND: We aimed to assess the efficacy and safety of sequential or
simultaneous telomerase vaccination (GV1001) in combination with chemotherapy in
patients with locally advanced or metastatic pancreatic cancer.
METHODS: TeloVac was a three-group, open-label, randomised phase 3 trial. We
recruited patients from 51 UK hospitals. Eligible patients were treatment naive,
aged older than 18 years, with locally advanced or metastatic pancreatic ductal
adenocarcinoma, and Eastern Cooperative Oncology Group performance status of
0-2. Patients were randomly assigned (1:1:1) to receive either chemotherapy
alone, chemotherapy with sequential GV1001 (sequential chemoimmunotherapy), or
chemotherapy with concurrent GV1001 (concurrent chemoimmunotherapy). Treatments
were allocated with equal probability by means of computer-generated random
permuted blocks of sizes 3 and 6 in equal proportion. Chemotherapy included six
cycles of gemcitabine (1000 mg/m(2), 30 min intravenous infusion, at days 1, 8,
and 15) and capecitabine (830 mg/m(2) orally twice daily for 21 days, repeated
every 28 days). Sequential chemoimmunotherapy included two cycles of combination
chemotherapy, then an intradermal lower abdominal injection of
granulocyte-macrophage colony-stimulating factor (GM-CSF; 75 μg) and GV1001
(0·56 mg; days 1, 3, and 5, once on weeks 2-4, and six monthly thereafter).
Concurrent chemoimmunotherapy included giving GV1001 from the start of
chemotherapy with GM-CSF as an adjuvant. The primary endpoint was overall
survival; analysis was by intention to treat. This study is registered as an
International Standard Randomised Controlled Trial, number ISRCTN4382138.
FINDINGS: The first patient was randomly assigned to treatment on March 29,
2007, and the trial was terminated on March 27, 2011. Of 1572 patients screened,
1062 were randomly assigned to treatment (358 patients were allocated to the
chemotherapy group, 350 to the sequential chemoimmunotherapy group, and 354 to
the concurrent chemoimmunotherapy group). We recorded 772 deaths; the 290
patients still alive were followed up for a median of 6·0 months (IQR 2·4-12·2).
Median overall survival was not significantly different in the chemotherapy
group than in the sequential chemoimmunotherapy group (7·9 months [95% CI
7·1-8·8] vs 6·9 months [6·4-7·6]; hazard ratio [HR] 1·19, 98·25% CI 0·97-1·48,
p=0·05), or in the concurrent chemoimmunotherapy group (8·4 months [95% CI
7·3-9·7], HR 1·05, 98·25% CI 0·85-1·29, p=0·64; overall log-rank of χ(2)2df=4·3;
p=0·11). The commonest grade 3-4 toxic effects were neutropenia (68 [19%]
patients in the chemotherapy group, 58 [17%] patients in the sequential
chemoimmunotherapy group, and 79 [22%] patients in the concurrent
chemoimmunotherapy group; fatigue (27 [8%] in the chemotherapy group, 35 [10%]
in the sequential chemoimmunotherapy group, and 44 [12%] in the concurrent
chemoimmunotherapy group); and pain (34 [9%] patients in the chemotherapy group,
39 [11%] in the sequential chemoimmunotherapy group, and 41 [12%] in the
concurrent chemoimmunotherapy group).
INTERPRETATION: Adding GV1001 vaccination to chemotherapy did not improve
overall survival. New strategies to enhance the immune response effect of
telomerase vaccination during chemotherapy are required for clinical efficacy.
FUNDING: Cancer Research UK and KAEL-GemVax. |
Which is the E3 ubiquitin ligase which ubiquitinates IkB leading to its proteasomal degradation? | IκB degradation involves ubiquitination mediated by a specific E3 ubiquitin ligase SCF(β-TrCP). SCF(β-TrCP) -mediated IκB ubiquitination and degradation is a very efficient process, often resulting in complete degradation of the key inhibitor IκBα within a few minutes of cell stimulation. | NF-kappaB (nuclear factor-kappaB) is a collective name for inducible dimeric
transcription factors composed of members of the Rel family of DNA-binding
proteins that recognize a common sequence motif. NF-kappaB is found in
essentially all cell types and is involved in activation of an exceptionally
large number of genes in response to infections, inflammation, and other
stressful situations requiring rapid reprogramming of gene expression. NF-kappaB
is normally sequestered in the cytoplasm of nonstimulated cells and consequently
must be translocated into the nucleus to function. The subcellular location of
NF-kappaB is controlled by a family of inhibitory proteins, IkappaBs, which bind
NF-kappaB and mask its nuclear localization signal, thereby preventing nuclear
uptake. Exposure of cells to a variety of extracellular stimuli leads to the
rapid phosphorylation, ubiquitination, and ultimately proteolytic degradation of
IkappaB, which frees NF-kappaB to translocate to the nucleus where it regulates
gene transcription. NF-kappaB activation represents a paradigm for controlling
the function of a regulatory protein via ubiquitination-dependent proteolysis,
as an integral part of a phosphorylationbased signaling cascade. Recently,
considerable progress has been made in understanding the details of the
signaling pathways that regulate NF-kappaB activity, particularly those
responding to the proinflammatory cytokines tumor necrosis factor-alpha and
interleukin-1. The multisubunit IkappaB kinase (IKK) responsible for inducible
IkappaB phosphorylation is the point of convergence for most
NF-kappaB-activating stimuli. IKK contains two catalytic subunits, IKKalpha and
IKKbeta, both of which are able to correctly phosphorylate IkappaB. Gene
knockout studies have shed light on the very different physiological functions
of IKKalpha and IKKbeta. After phosphorylation, the IKK phosphoacceptor sites on
IkappaB serve as an essential part of a specific recognition site for
E3RS(IkappaB/beta-TrCP), an SCF-type E3 ubiquitin ligase, thereby explaining how
IKK controls IkappaB ubiquitination and degradation. A variety of other
signaling events, including phosphorylation of NF-kappaB, hyperphosphorylation
of IKK, induction of IkappaB synthesis, and the processing of NF-kappaB
precursors, provide additional mechanisms that modulate the level and duration
of NF-kappaB activity. Although constitutive activation of beta-catenin/Tcf signalling is implicated in
the development of human cancers, the mechanisms by which the beta-catenin/Tcf
pathway promotes tumorigenesis are incompletely understood. Messenger RNA
turnover has a major function in regulating gene expression and is responsive to
developmental and environmental signals. mRNA decay rates are dictated by
cis-acting elements within the mRNA and by trans-acting factors, such as
RNA-binding proteins (reviewed in refs 2, 3). Here we show that beta-catenin
stabilizes the mRNA encoding the F-box protein betaTrCP1, and identify the
RNA-binding protein CRD-BP (coding region determit-binding protein) as a
previously unknown target of beta-catenin/Tcf transcription factor. CRD-BP binds
to the coding region of betaTrCP1 mRNA. Overexpression of CRD-BP stabilizes
betaTrCP1 mRNA and elevates betaTrCP1 levels (both in cells and in vivo),
resulting in the activation of the Skp1-Cullin1-F-box protein (SCF)(betaTrCP) E3
ubiquitin ligase and in accelerated turnover of its substrates including IkappaB
and beta-catenin. CRD-BP is essential for the induction of both betaTrCP1 and
c-Myc by beta-catenin signalling in colorectal cancer cells. High levels of
CRD-BP that are found in primary human colorectal tumours exhibiting active
beta-catenin/Tcf signalling implicates CRD-BP induction in the upregulation of
betaTrCP1, in the activation of dimeric transcription factor NF-kappaB and in
the suppression of apoptosis in these cancers. The nuclear factor-κB (NF-κB) signaling pathway is a busy ground for the action
of the ubiquitin-proteasome system; many of the signaling steps are coordinated
by protein ubiquitination. The end point of this pathway is to induce
transcription, and to this end, there is a need to overcome a major obstacle, a
set of inhibitors (IκBs) that bind NF-κB and prohibit either the nuclear entry
or the DNA binding of the transcription factor. Two major signaling steps are
required for the elimination of the inhibitors: activation of the IκB kinase
(IKK) and degradation of the phosphorylated inhibitors. IKK activation and IκB
degradation involve different ubiquitination modes; the latter is mediated by a
specific E3 ubiquitin ligase SCF(β-TrCP) . The F-box component of this E3,
β-TrCP, recognizes the IκB degron formed following phosphorylation by IKK and
thus couples IκB phosphorylation to ubiquitination. SCF(β-TrCP) -mediated IκB
ubiquitination and degradation is a very efficient process, often resulting in
complete degradation of the key inhibitor IκBα within a few minutes of cell
stimulation. In vivo ablation of β-TrCP results in accumulation of all the IκBs
and complete NF-κB inhibition. As many details of IκB-β-TrCP interaction have
been worked out, the development of β-TrCP inhibitors might be a feasible
therapeutic approach for NF-κB-associated human disease. However, we may still
need to advance our understanding of the mechanism of IκB degradation as well as
of the diverse functions of β-TrCP in vivo. |
Is c-met involved in the activation of the Akt pathway? | HGF-induced activation of c-Met is playing a pivotal role in the stimulation of c-Src activation, resulting in induction of phosphatidylinositol 3-kinase complexes p85α/p110α and p85α/p110δ, which is required for Akt-mediated activation of mammalian target of rapamycin, with consequent inhibition of IκB kinase and nuclear factor-κB activation, resulting in enhanced cell survival. | Acute irreparable UV-induced DNA damage leads to apoptosis of epidermal
keratinocytes (KC) and the formation of sunburn cells, whereas less severely
damaged cells survive but harbor the potential of tumor formation. Here we
report that hepatocyte growth factor/scatter factor (HGF/SF) prevents
UVB-induced apoptosis in primary KC cultured in vitro. When we analyzed the
signaling pathways initiated by the HGF/SF receptor c-met, we found that the
phosphatidylinositol (PI) 3-kinase and its downstream-element AKT and the
mitogen-activated protein (MAP) kinase were activated. Inhibition of PI 3-kinase
led to a complete abrogation of the anti-apoptotic effect of HGF/SF, whereas
blockade of the MAP kinase pathway had no effect. In contrast to the observation
with primary KC, HGF/SF could not enhance survival after UVB irradiation of
HaCaT and A431 cell lines, despite the fact that in these cells the PI 3-kinase
and MAP kinase pathways were also activated by HGF/SF. Cell cycle analysis of KC
revealed a G(2)/M arrest after UVB irradiation and a complete loss of
proliferating cells. Because HGF/SF in the skin is produced by dermal
fibroblasts, our findings suggest that the HGF/SF-mediated rescue of KC from
apoptosis represents an important paracrine loop by which UVB-damaged KC can be
kept alive to maintain the epidermal barrier function but cannot further
proliferate, thereby preventing the induction of epithelial skin tumors. The mechanisms by which growth factors trigger signal transduction pathways
leading to protection against apoptosis are of great interest. In this study, we
investigated the effect of hepatocyte growth factor (HGF/SF) and epidermal
growth factor (EGF) on adriamycin (ADR)-induced apoptosis. Treatment of human
epithelial MKN74 cells with ADR, a DNA topoisomerase IIalpha inhibitor, caused
apoptosis. However, cells pretreated with HGF/SF, but not those pretreated with
EGF, were resistant to this apoptosis. The protective effect of HGF/SF against
the ADR-induced apoptosis was abolished in the presence of either LY294002, an
inhibitor of phosphatidylinositol-3'-OH kinase (PI3-K) or
1L-6-hydroxymethyl-chiro-inositol 2-(R)-2-O-methyl-3-O-octadecylcarbonate, an
inhibitor of Akt, thus implicating the activation of PI3-K-Akt signaling in the
antiapoptotic action of HGF/SF. Immunoblotting analysis revealed that HGF/SF
stimulated the sustained phosphorylation of Akt for several hours but that EGF
stimulated the phosphorylation only transiently. Furthermore, ADR-induced
activation of caspase-9, a downstream molecule of Akt, was inhibited for at
least 24 h after HGF/SF stimulation, but it was not affected by EGF stimulation.
Cell-surface biotin-labeling analysis showed that the HGF/SF receptor remained
on the cell surface until at least 30 min after HGF/SF addition but that the EGF
receptor level on the cell surface was attenuated at an earlier time after EGF
addition. These results indicate that HGF/SF, but not EGF, transmitted
protective signals against ADR-induced apoptosis by causing sustained activation
of the PI3-K-Akt signaling pathway. Furthermore, the difference in antiapoptotic
capacity between HGF/SF and EGF is explained, at least in part, by the delayed
down-regulation of the HGF/SF receptor. This study determines the effect of hepatocyte growth factor (HGF) on
post-infarction left ventricular (LV) remodeling and cardiac function. In mice,
on day 1 after myocardial infarction (MI), HGF (0.45 mg/kg per day) was injected
into the tail vein for 7 days (n = 12). In the control mice (n = 12), 0.9%
sodium chloride was injected instead of HGF. Hemodynamic data were obtained in
vehicle treated control and HGF-treated hearts 4 weeks after the onset of MI. In
the HGF-treated group, cardiac function was well preserved as indicated by LV
pressure-volume relationship. These mice exhibited better LV systolic and
diastolic function. The infarcted LV wall in HGF-treated heart was thicker as
compared to vehicle treated group. Fibrosis and infarct size of the ventricular
wall was significantly reduced in the HGF-treated hearts.
5-Bromo-2'-deoxy-uridine (BrdU) and Ki67 positive cardiomyocytes were observed
in the border area of the HGF-treated infarcted hearts. c-Met and c-kit positive
cardiomyocytes were observed in the border area and epicardium. Angiogenesis was
significantly enhanced in HGF-treated hearts as determined by vessel density per
unit area. A significant reduction in apoptosis in the HGF-treated hearts was
observed compared with control hearts, and was strongly associated with
increased Akt activation. Treatment with HGF improved heart function through
angiogenesis, ventricular wall thickening, and hypertrophy of cardiomyocytes.
The antiapoptotic effect of HGF was mediated by activation of PI3-kinase/Akt
pathway. PURPOSE: The inhibitor of the apoptosis protein (IAP) family members, such as
the X-linked IAP (XIAP), survivin, and livin, are essential for cell survival
and antiapoptosis in colorectal cancer cells. We hypothesized that the
hepatocyte growth factor (HGF) activation in colorectal cancer via c-Met
receptor regulates IAP proteins through Akt signaling.
EXPERIMENTAL DESIGN: The level of IAPs and C-Met mRNA expression was assessed
using a quantitative real-time reverse transcriptase-PCR (RT-PCR) assay on
colorectal normal mucosa (n = 13), adenomas (n = 6), and colorectal cancer
tumors (n = 50). The role of HGF/C-Met pathway through Akt and XIAP was
investigated by small interfering RNA (siRNA) and quantitative RT-PCR analysis
of colorectal cancer lines.
RESULTS: Of the IAPs, only XIAP showed significant correlation to tumor
development and progression. XIAP mRNA level in primary colorectal cancer was
significantly higher than that in colorectal normal mucosa (P = 0.01); liver
metastases was significantly higher than primary colorectal cancer tumors (P =
0.04); and primary colorectal cancer N1/N2 cases were significantly higher than
N0 cases (P = 0.008). HGF stimulation of colorectal cancer lines enhanced XIAP
mRNA expression but not other IAPs. Activation of XIAP expression by HGF was
inhibited by siRNA targeting Akt1 and Akt2.
CONCLUSIONS: Activation of C-MET enhances XIAP through the Akt pathway. XIAP
up-regulation was shown to be correlated to colorectal cancer tumor progression.
The Akt-XIAP pathway may be a potential molecular target for regulating
colorectal cancer progression. Hepatocyte growth factor (HGF) is a pleiotropic cytokine promoting
proliferation, migration and survival in several cell types. HGF and its cognate
receptor c-Met are expressed in cardiac cells during early cardiogenesis, but
data concerning its role in cardiac differentiation of embryonic stem cells
(ESCs) and the underlying molecular mechanisms involved are limited. In the
present study we show that HGF significantly increases the number of beating
embryoid bodies of differentiating ESCs without affecting beating frequency.
Furthermore, HGF up-regulates the expression of the cardiac-specific
transcription factors Nkx 2.5 and GATA-4 and of markers of differentiated
cardiomyocytes, i.e. alpha-MHC, beta-MHC, ANF, MLC2v and Troponin T. The
HGF-induced increase in Nkx 2.5 expression was inhibited by co-treatment with
the PI3 kinase inhibitors Wortmannin and LY294002, but not by its inactive
homolog LY303511, suggesting an involvement of the PI3 kinase/Akt pathway in
this effect. We conclude that HGF is an important growth factor involved in
cardiac differentiation and/or proliferation of ESCs and may therefore be
critical for the in vitro generation of pre- or fully differentiated
cardiomyocytes as required for clinical use of embryonic stem cells in cardiac
diseases. The FasL-Fas couple is a general death mediator whose activated signals lead to
caspase-8 activation and apoptosis in adult hepatocytes. Suppression of
caspase-8 activation and cell death is a protective mechanism modulated by the
FLICE-Like Inhibitory Protein (FLIP). Although hepatocyte growth factor (HGF)
and its receptor Met are known to mediate cell survival in developing livers,
the molecular mechanisms involved in this process are poorly understood. We show
here that Met activation by HGF impairs Fas-triggered apoptosis of primary
embryonic hepatocytes and cell survival correlates with inhibition of caspase-8
and caspase-3 activities. Furthermore, we found that HGF treatment prevents
degradation of FLIPL triggered by Fas activation. In contrast to this, Met
activation does not modulate FLIPL levels and its stability in untreated cells,
thus showing the specificity of this regulatory mechanism for embryonic
hepatocyte survival. Knocking down FLIP expression abolishes the ability of Met
to inhibit Fas-triggered hepatocyte death, demonstrating the functional
requirement of FLIP in HGF anti-apoptotic signals. By combining genetic and
pharmacological approaches, we also demonstrate that the PI3K-Akt pathway is
required in embryonic hepatocytes to prevent Fas-triggered FLIP degradation and
death. Thus, Met acting on PI3K and Akt ensures high levels of FLIPL, and
disruption of this pathway contributes to hepatic apoptosis and possibly to
Fas-related liver diseases. PURPOSE: Uveal melanoma is the most common primary intraocular maligcy in
adult humans. Unlike cutaneous melanoma, uveal melanoma disseminates
preferentially to the liver through the hematogenous system. To date, the
mechanism underlying this metastatic homing is largely unknown. This study
investigated the effect of hepatocyte growth factor (HGF)-triggered signaling
pathways to identify the role of HGF and its downstream effectors in inducing
the migration of uveal melanoma cells.
METHODS: Migration of uveal melanoma cells was measured by in vitro wound
healing and transwell migration assays. The expression and translocation of
c-Met were detected using indirect immunofluorescence. The activation of
extracellular signal-regulated kinase (ERK)1/2 and phosphatidylinositol 3-kinase
(PI3K)/protein kinase B (Akt) pathways was analyzed using specific antibodies
against phospho-ERK1/2 and phospho-Akt. The impact of HGF treatment on the
expression of cell adhesion molecules was measured using Western blotting.
RESULTS: HGF was found to enhance cell migration, and that HGF-induced migration
depends on PI3K/Akt pathway. The activation of PI3K/Akt pathway induced by the
HGF/c-Met axis is involved in the downregulation of cell adhesion molecules
E-cadherin and beta-catenin, contributing to the attenuation of cell-cell
adhesion and promoting the enhanced motility and migration of uveal melanoma
cells. On HGF stimulation, receptor c-Met is translocated to the nucleus in a
ligand-dependent manner, suggesting that c-Met may modulate the expression of
genes involved in melanoma cell migration.
CONCLUSIONS: Data from this study directly linked the central PI3K/Akt pathway
to uveal melanoma migration and pointed to new avenues for therapeutic
intervention in hepatic metastasis. During central nervous system development, growth factors and their associated
receptor protein tyrosine kinases regulate many neuronal functions such as
neurite extension and dendrite maturation. Hepatocyte growth factor (HGF) and
its receptor, c-Met, can promote formation of neurites and enhance elaboration
of dendrites in mature neurons, but their effects on the early stages of
dendrite maturation in hippocampal neurons and the signaling pathways by which
they promote dendrite formation have not been studied. Exogenous HGF treatment
effectively enhanced the phosphorylation and activation of c-Met in cultured
hippocampal neurons at 4 days in vitro. HGF treatment increased the number of
dendrites and promoted dendrite elongation in these neurons. Consistent with
these results, HGF activated Akt, which phosphorylates glycogen synthase
kinase-3beta (GSK-3beta) to inactivate it, and reduced phosphorylation of
microtubule-associated protein 2 (MAP2), which can promote microtubule
polymerization and dendrite elongation when dephosphorylated. Conversely,
pharmacological inhibition of c-Met with its specific inhibitor, PHA-665752, or
genetic knock-down of c-Met with short hairpin RNAs (shRNAs) suppressed
HGF-induced phosphorylation of Akt and GSK-3beta, increased phosphorylation of
MAP2, and reduced dendrite number and length in cultured hippocampal neurons.
Moreover, suppressing c-Met with PHA-665752 or by shRNA decreased MAP2
expression. Inhibiting Akt activity with the phosphoinositide-3-kinase inhibitor
LY294002 or Akt inhibitor X suppressed HGF-induced phosphorylation of GSK-3beta,
increased MAP2 phosphorylation, and blocked the ability of HGF to enhance
dendritic length. These observations indicate that HGF and c-Met can regulate
the early stages of dendrite maturation via activation of the Akt/GSK-3beta
pathway. The development of the mammary gland requires an integrated response to specific
growth factors and steroid hormones. Hepatocyte growth factor (HGF) and its
tyrosine kinase receptor, MET, are expressed and temporally regulated during
mammary development and differentiation. Epidermal growth factor receptor (EGFR)
and its ligands have also been implicated in mammary gland growth and
morphogenesis. Since both cytokines seem to exert a morphogenic program in this
tissue, we have investigated the possible concerted action of EGF and HGF on the
HC11 cell line, a widely used model of nontumorigenic mammary cells. Western
blot analysis indicated that HC11 expressed MET and EGFR, and showed ERK1/2 and
AKT activation following HGF or EGF treatment. Analysis by real-time PCR and
western blot showed that after an EGF but not HGF or insulin-like growth
factor-I treatment, HC11 mammary cells exhibited an increase in MET expression
at both the mRNA and protein levels, which was dependent on the AKT pathway.
Simultaneous treatment with HGF and EGF increased proliferation, scatter, and
invasion as assessed by cell count, cell cycle, scatter, and transwell assays.
AKT inhibition did not influence the cooperation on proliferation or invasion
after HGF+EGF treatment, while ERK1/2 inhibition abolished MET/EGFR cooperation
on proliferation. HGF+EGF treatment increased the duration of ERK1/2 and AKT
activation compared to HGF or EGF alone. All these data indicate that a
crosstalk between the EGF and HGF pathways in mammary epithelial cells may
modulate the development of the mammary gland. Certain tumor cell responses to the growth factor-inducible early response gene
product CCN1/Cyr61 overlap with those induced by the hepatocyte growth factor
(HGF)/c-Met signaling pathway. In this study, we investigate if Cyr61 is a
downstream effector of HGF/c-Met pathway activation in human glioma cells. A
semiquantitative immunohistochemical analysis of 112 human glioma and normal
brain specimens showed that levels of tumor-associated Cyr61 protein correlate
with tumor grade (P < 0.001) and with c-Met protein expression (r(2) = 0.4791, P
< 0.0001). Purified HGF rapidly upregulated Cyr61 mRNA (peak at 30 minutes) and
protein expression (peak at 2 hours) in HGF(-)/c-Met(+) human glioma cell lines
via a transcription- and translation-dependent mechanism. Conversely, HGF/c-Met
pathway inhibitors reduced Cyr61 expression in HGF(+)/c-Met(+) human glioma cell
lines in vitro and in HGF(+)/c-Met(+) glioma xenografts. Targeting Cyr61
expression with small interfering RNA (siRNA) inhibited HGF-induced cell
migration (P < 0.01) and cell growth (P < 0.001) in vitro. The effect of Cyr61
on HGF-induced Akt pathway activation was also examined. Cyr61 siRNA had no
effect on the early phase of HGF-induced Akt phosphorylation (Ser(473)) 30
minutes after stimulation with HGF. Cyr61 siRNA inhibited a second phase of Akt
phosphorylation measured 12 hours after cell stimulation with HGF and also
inhibited HGF-induced phosphorylation of the Akt target glycogen synthase kinase
3alpha. We treated preestablished subcutaneous glioma xenografts with Cyr61
siRNA or control siRNA by direct intratumoral delivery. Cyr61 siRNA inhibited
Cyr61 expression and glioma xenograft growth by up to 40% in a dose-dependent
manner (P < 0.05). These results identify a Cyr61-dependent pathway by which
c-Met activation mediates cell growth, cell migration, and long-lasting
signaling events in glioma cell lines and possibly astroglial maligcies. Hepatocyte growth factor modulates activation and antigen-presenting cell
function of dendritic cells. However, the molecular basis for immunoregulation
of dendritic cells by hepatocyte growth factor is undefined. In the current
study, we demonstrate that hepatocyte growth factor exhibits inhibitory effect
on dendritic cell activation by blocking IκB kinase activity and subsequent
nuclear factor-κB activation. Inhibition of IκB kinase is mediated by hepatocyte
growth factor-induced activation of c-Src. Proximal signaling events induced in
dendritic cells by hepatocyte growth factor include a physical association of
c-Src with the hepatocyte growth factor receptor c-MET and concomitant
activation of c-Src. Activation of c-Src in turn establishes a complex
consisting of phosphatidylinositol 3-kinase and c-MET, and promotes downstream
activation of the phosphatidylinositol 3-kinase/AKT pathway and mammalian target
of rapamycin. Blocking activation of c-Src, phosphatidylinositol 3-kinase and
mammalian target of rapamycin prevents hepatocyte growth factor-induced
inhibition of IκB kinase, nuclear factor-κB and dendritic cell activation.
Notably, hepatocyte growth factor-stimulated c-Src activation results in
induction of phosphatidylinositol 3-kinase complexes p85α/p110α and p85α/p110δ,
which is required for activation of mammalian target of rapamycin, and
consequent inhibition of IκB kinase and nuclear factor-κB activation. Our
findings, for the first time, have identified the c-Src-phosphatidylinositol
3-kinase-AKT-mammalian target of rapamycin pathway that plays a pivotal role in
mediating the inhibitory effects of hepatocyte growth factor on dendritic cell
activation by blocking nuclear factor-κB signaling. Hepatocyte growth factor (HGF) is up-regulated in tissue repair and has been
implicated in playing a role in this process through its anti-apoptotic and
proliferative activities. Cyclooxygenase-2 (COX-2) is an inducible enzyme in the
biosynthetic pathway of prostaglandins, and its activation has been shown to
play an important role in cell growth. We previously reported that HGF
significantly inhibited anoikis, possibly through the up-regulation of COX-2
expression in the endometrial RL95-2 cancer cell line. Here, we report that i)
treatment of RL95-2 cells with HGF resulted in phosphorylation of the HGF
receptor c-Met, activation of Akt and IκB, translocation of NF-κB into the
nucleus, and up-regulation of COX-2 mRNA; ii) the IκB-α phosphorylation
inhibitor BAY11-7082 and the selective COX-2 inhibitor CAY10452 blocked
HGF-mediated anoikis resistance in RL95-2 cells; and iii) HGF induced migration
and invasion in RL95-2 cells, while the phosphatidylinositol 3-kinase (PI3K)
inhibitor LY294002 and CAY10452 blocked these effects of HGF stimulation. Our
data suggest that HGF possesses chemotactic ability, has anti-apoptosis action,
and induces cellular infiltration via the PI3K/Akt pathway; it also triggers
NF-κB activation and up-regulates COX-2 gene expression in endometrial cancer
cells. Osteosarcoma is a common maligt bone tumor. Cisplatin (CDDP) achieves a high
response rate in osteosarcoma. However, osteosarcoma usually exhibits cisplatin
resistance. Many members of receptor tyrosine kinases (RTKs)(1) have been
demonstrated to be overexpressed and constitutively activated in various tumors
including osteosarcoma, resulting in maligt progression and insensitivity to
chemotherapy. Hepatocyte growth factor receptor (HGFR/c-Met) also appears
overexpressed and activated in osteosarcoma cells. Nevertheless, which role of
c-Met activation in cisplatin efficacy against osteosarcoma cells remains still
elusive. This study found that inhibition of c-Met activity by PHA-665752 or
blockade of the interaction of autocrined HGF with c-Met with neutralizing
anti-HGF antibody promoted cisplatin efficacy in osteosarcoma cells, while
addition of recombit human HGF (rh-HGF) counteracts cisplatin cytotoxicity.
Specifically, we demonstrated that inhibition of c-Met activity led to
suppression of the PI3K-Akt pathway, thus enhancing cisplatin chemosensitivity.
Our study clearly suggests that inhibition of c-Met activity can effectively
sensitize osteosarcoma cells to cisplatin via suppression of the PI3K-Akt
signaling. Epithelial-mesenchymal transition (EMT) has recently been studied to elucidate
mechanisms of the liver metastatic process. We investigated EMT in the process
of liver metastasis and the effects of chemotherapy on EMT cells as therapeutic
strategy for colorectal liver metastasis. We used the CT26 murine colorectal
carcinoma cell line to create an in vivo mouse liver metastasis model. Liver
tumors were stained immuno-histochemically. Expression of proteins associated
with TGF-β/Smad and hepatocyte growth factor (HGF)/c-Met pathways were
investigated by western blotting. Cells with c-Met mRNA knockdown by siRNA
techniques showed clearly reduced liver metastases compared with regular cells
at 21 days. TGF-β and HGF induced EMT expression, but signal transduction was
quite different. TGF-β induced ERK, but not Akt phosphory-lation. HGF mediated
both ERK and Akt phosphorylation. Akt inhibitor blocked Akt phosphorylation but
did not affect TGF-β-induced activation of ERK, Snail and Slug. U-0126 did not
reduce Snail activity by TGF-β at a concentration to block ERK phosphorylation.
However, Akt inhibitor and U-0126 completely inhibited HGF-induced Slug
activation. 5-FU mediated cell death in the EMT process induced by TGF-β more
effectively than HGF. ERK/Akt signaling, but not the Smad pathway, may be one of
the main processes in HGF-induced EMT, despite the Smad pathway, but not
ERK/Akt, being critical for TGF-β-induced EMT. The MAPK/Akt pathway is
indispensable in HGF/c-Met signaling. The ERK/Akt pathway particularly may be
critical in the HGF-induced EMT process. However, long-term use of
chemotherapeutic agents may induce drug resistance and distant metastases
through EMT-related signaling pathway activation. A better understanding of the pathophysiology and evolution of non-small cell
lung cancer (NSCLC) has identified a number of molecular targets and spurred
development of novel targeted therapeutic agents. The MET receptor tyrosine
kinase and its ligand hepatocyte growth factor (HGF) are implicated in tumor
cell proliferation, migration, invasion, and angiogenesis in a broad spectrum of
human cancers, including NSCLC. Amplification of MET has been reported in
approximately 5%-22% of lung tumors with acquired resistance to small-molecule
inhibitors of the epidermal growth factor receptor (EGFR). Resistance to EGFR
inhibitors is likely mediated through downstream activation of the
phosphoinositide 3-kinase /AKT pathway. Simultaneous treatment of resistant
tumors with a MET inhibitor plus an EGFR inhibitor can abrogate activation of
downstream effectors of cell growth, proliferation, and survival, thereby
overcoming acquired resistance to EGFR inhibitors. Development and preclinical
testing of multiple agents targeting the HGF-MET pathway, including monoclonal
antibodies targeting HGF or the MET receptor and small-molecule inhibitors of
the MET tyrosine kinase, have confirmed the crucial role of this pathway in
NSCLC. Several agents are now in phase III clinical development for the
treatment of NSCLC. This review summarizes the role of MET in the
pathophysiology of NSCLC and in acquired resistance to EGFR inhibitors and
provides an update on progress in the clinical development of inhibitors of MET
for treatment of NSCLC. |
Is pregnancy an additional risk during during H1N1 infection? | Pregnant women are at increased risk for complications from pandemic influenza H1N1 virus infection. Pregnant women, because of their altered immunity and physiological adaptations, are at higher risk of developing pulmonary complications, especially in the second and third trimesters. Pregnancy, particularly during the third trimester, increases the risk of complications and early antiviral treatment is associated with improved outcomes. | BACKGROUND: Pregt women have been identified as a group at risk of increased
morbidity and mortality associated with the pandemic H1N1 influenza A 2009
(H1N1/09) outbreak.
METHODS: Six hospitals in the state of Victoria, Australia, contributed
retrospective and prospective demographic and clinical data, reason for
admission data, and maternal and fetal outcome data for women with
laboratory-confirmed H1N1/09 admitted to the hospital from 20 May 2009 through
31 July 2009.
RESULTS: Forty-three cases were reported during the study period, including 8
intensive care unit admissions, 1 maternal death, 2 fetal deaths, and 1 neonatal
death. The most common reason for admission was uncomplicated influenza-like
illness. Patients hospitalized for uncomplicated influenza-like illness had a
length of stay significantly less than those with confirmed pneumonia.
Thirty-six percent of women delivered during the hospitalization. Of the women
delivering before 37 weeks' gestation, almost all had pneumonia. Almost half of
our case series had no other comorbidity, a large proportion (77%) of women
received antivirals, and 56% received antibiotics. The incidence of
hospitalization was estimated at 0.46% (95% confidence interval, 0.31%-0.66%) of
all 6094 pregt women in the third trimester during the 3-month study period.
The incidence of hospitalization in the second trimester was estimated at 0.21%
(95% confidence interval, 0.11%-0.36%).
CONCLUSIONS: This case series confirms a high number of complications in
pregt women due to pandemic H1N1/09. Many of these women had comorbidities,
although almost 50% of the women in this case series who required
hospitalization did not have an additional risk factor other than being
pregt. BACKGROUND: Pregt women have been identified as a group at risk, both for
respiratory complications than for the admissions to the Intensive Care Unit
(ICU) during the 2009 H1N1 influenza pandemic (pdm). The purpose of this
prospective register-based cohort-study was to characterize the clinical
virulence of the pdm (H1N1/09)v during pregcy in La Réunion.
METHODS/PRINCIPAL FINDINGS: Over a twelve-week pdm wave (13 July to 3 October
2009), 294 pregt women presented with an influenza-like illness (ILI) to one
of the three maternity departments of the South Reunion area, Indian Ocean. Out
of these, 278 were checked by RT-PCR for influenza viruses (157 positive and 121
negative, of whom, 141 with pdm flu and 132 with ILIs of non pdm origin, 5
untyped). The median body temperature was higher in women experiencing pdm flu
than in those with non pdm ILI (38.9 degrees C versus 38.3 degrees C, P<0.0001),
without evidence linked to circulating viremia. Oseltamivir was given for 86% of
pdm flu cases in a median time inferior than 48 hrs (range 0-7 days). The
hospitalization rate for pdm flu was of 60% and not associated with underlying
conditions. Six viral pneumonia and fourteen asthma attacks were observed among
84 hospitalized pdm flu cases, of whom, only one led to the ICU for an acute
lung injury. No maternal death occurred during the pdm wave. None adverse
pregcy outcome was associated with pdm flu. No congenital birth defect, nor
early-onset neonatal influenza infection was attributable to pdm flu exposure.
CONCLUSIONS/SIGNIFICANCE: This report mitigates substantially the presumed
severity of pandemic H1N1/09 influenza infection during pregcy. The reasons
for which the clinical burden of H1N1/09 influenza virus may differ worldwide
raise questions about a differential local viral-strain effect and public health
preparedness, notably in timely access to special care and antiviral treatments. BACKGROUND: Emerging data suggest that pregcy conveys high risk for severe
complications from the 2009 pandemic influenza A virus (2009 H1N1) infection.
CASE: We describe an infected pregt woman with critical illness owing to
acute respiratory distress syndrome despite previous vaccination. Early
serologic testing indicated absent immunity, followed 11 days later by a robust
immune response. The patient required mechanical ventilation for 11 days, but
ultimately improved, and was discharged home on hospital day 14.
CONCLUSION: With the expectation that 2009 H1N1 will continue to cause disease
in the immediate future, the virus has been included as a component of the
2010-2011 seasonal influenza vaccine. Vaccination of pregt women is strongly
encouraged. However, regardless of vaccination history, clinicians should remain
vigilant for 2009 H1N1 infection when the virus is in circulation, and should
not delay antiviral treatment of pregt women with suspected influenza. AIM: Evaluation of alterations of immune response regulation and possible risk
of antenatal development of fetus in postvaccination period in pregt women
immunized against influenza A (H1N1).
MATERIALS AND METHODS: Women were vaccinated with MonoGrippol plus vaccine in
the II trimester of physiological pregcy. At certain intervals ofthe
vaccination period (before the vaccination, 7 and 30 days after the vaccination)
major biochemical markers in blood sera (alanine aminotransferase, aspartate
aminotransferase, lactate dehydrogenase, alkaline phosphatase, creatinine, urea)
and levels of key cytokines in spontaneous and stimulated test (IL-1alpha,
IL-1RA, IL-2, IL-4, IL-10, IFNgamma, TNFalpha) were evaluated. Vaccination
safety for the fetus and trophoblast development was evaluated by using human
chorionic gonadotropin (HCG), alpha-fetoprotein (AFP) and trophoblasitc
beta-1-glycoprotein (TBG) levels.
RESULTS: During vaccination in 13% of cases mild local reactions were noted, in
26.1%--general systemic reactions in the form of weakness, dizziness and
headaches. Levels of major biochemical markers at days 7 and 30 after the
vaccination did not have any significant difference from the initial values (p >
0.05). Cytokine levels in spontaneous and stimulated tests also did not change
significantly. Markers of the course of pregcy and fetus development (HCG,
AFP and TBG) in the two groups observed had comparable values.
CONCLUSION: Vaccination of pregt women against influenza A (H1N1) by Russian
subunit formulation (MonoGrippol plus) showed reactogenicity comparable to
control group by the level of influence on general metabolic and immunologic
homeostasis and on the course of pregcy, which is an evidence of its safety. OBJECTIVES: To describe the clinical characteristics of the pregt women who
were hospitalized in a tertiary referral hospital with pandemic influenza H1N1
2009 virus infection and neonatal outcomes from October 2009 to December 2009
during which the pandemic influenza cases peaked in Turkey.
MATERIALS AND METHODS: Twenty-five pregt women who were hospitalized with
influenza-like illness and who had laboratory confirmation for pandemic
influenza H1N1 virus infection were evaluated prospectively.
RESULTS: Of the 25 patients, 4 (16%) were in the first trimester, 8 (32%) were
in the second trimester, and 13 (52%) were in the third trimester. The median
time from the onset of symptoms to the initiation of antiviral therapy was 1 day
(range 1-9 days). Nineteen (76%) patients received oseltamivir treatment. It
took 1.6 days on the average for the fever defervescence after the initiation of
treatment or hospitalization. Of the 14 patients who underwent chest
radiography, three had findings consistent with pneumonia. The mean duration of
hospitalization was 4.8 days. Four women (16%) were admitted to an intensive
care unit, but there were no maternal or neonatal deaths in this series. At the
time of their H1N1 hospitalization, seven women delivered by cesarean at 33-40
weeks gestation, two vaginally at 38 weeks gestation, and two had an abortion at
10 weeks and 16 weeks of gestation, respectively. None of the infants had any
evidence of influenza infection.
CONCLUSION: Pregt women are at increased risk for complications from pandemic
influenza H1N1 virus infection. Timely medical attention with early recourse to
antiviral therapy is associated with a better outcome in H1N1-affected pregt
women. The aim of this study was to verify whether pregcy was a risk factor for
death in influenza A (H1N1)/2009 infection. We compared the case-fatality rates
for pandemic influenza among non-pregt women of childbearing age and pregt
women, besides investigating other factors that differentiated the groups in
relation to the outcomes. The data were collected from the National Information
System on Diseases of Notification (SINAN), of the Ministry of Health. The study
used cases with laboratory confirmation and included 1,861 women from 10 to 49
years of age, of whom 352 were pregt. The case-fatality rate during the 2009
pandemic was 4.5% for pregt women and 6.4% for non-pregt women (p =
0.197). Logistic regression did not show an association between pregcy and
death (OR = 0.7; 95%CI: 0.41-1.21). However, there were significant differences
between the two groups in relation to mean age, treatment with oseltamivir,
schooling, and presence of other risk factors. OBJECTIVE: Because pregcy suppresses the immune system, women at any stage of
pregcy are more susceptible to bacterial and viral infection. Pregt women
might thus be at increased risk of complications from pandemic H1N1 virus
infection, and illness may progress rapidly.
CASE REPORT: A 23-year-old primigravida at 9 weeks' gestation was presented to
our institution because of the sudden onset of sore throat, fever, chills, and
vomiting for 5 days. She was diagnosed with early pregcy H1N1 infection,
vulvar herpes infection, and impending intravascular disseminated coagulopathy.
Oseltamivir (Tamiflu) 75 mg and valacyclovir 500 mg were then administered
orally twice daily for 5 days. The patient's fever, chills, and vomiting
subsided 2 days later. The real-time reverse-transcriptase polymerase chain
reaction (RT-PCR) analysis of nasal discharge for influenza virus types A and B
showed positive results for the A/H1N1 influenza virus. The early pregcy was
terminated by therapeutic curettage at the patient's request. The surgical
specimen revealed products of conception with the presence of necrotic chorionic
villi, and focal lymphocytes in decidual tissue. RT-PCR analysis of gestational
tissue for A/H1N1 was negative.
CONCLUSION: Pregt women with H1N1 infection seem to benefit from antiviral
therapy. OBJECTIVE: To investigate whether an adjuvanted pandemic A/H1N1 2009 influenza
vaccine in pregcy was associated with an increased risk of fetal death.
DESIGN: Nationwide register based cohort study.
SETTING: Denmark.
PARTICIPANTS: All clinically recognised singleton pregcies that ended between
November 2009 and September 2010. Individual level data on exposure to an
inactivated AS03 pandemic A/H1N1 2009 influenza vaccine (Pandemrix) and
potential confounders were linked to the study cohort using a unique person
identifier.
MAIN OUTCOME MEASURES: The primary outcome measure was risk of fetal death
(spontaneous abortion and stillbirth combined) in H1N1 vaccinated compared with
unvaccinated pregcies, adjusting for propensity scores. Secondary outcome
measures were spontaneous abortion (between seven and 22 weeks' gestation) and
stillbirth (after 22 completed weeks' gestation).
RESULTS: The cohort comprised 54,585 pregcies; 7062 (12.9%) women were
vaccinated against pandemic A/H1N1 2009 influenza during pregcy. Overall,
1818 fetal deaths occurred (1678 spontaneous abortions and 140 stillbirths).
Exposure to the H1N1 vaccine was not associated with an increased risk of fetal
death (adjusted hazard ratio 0.79, 95% confidence interval 0.53 to 1.16), or the
secondary outcomes of spontaneous abortion (1.11, 0.71 to 1.73) and stillbirth
(0.44, 0.20 to 0.94). Estimates for fetal death were similar in pregt women
with (0.82, 0.44 to 1.53) and without comorbidities (0.77, 0.47 to 1.25).
CONCLUSION: This large cohort study found no evidence of an increased risk of
fetal death associated with exposure to an adjuvanted pandemic A/H1N1 2009
influenza vaccine during pregcy. BACKGROUND: A(H1N1)v2009 influenza vaccination of pregt women was a challenge
for health care providers, as little safety data were available.
METHODS: We prospectively followed the pregcies of women who were vaccinated
at any time during pregcy or ≤ 4 weeks prior to conception and compared these
outcomes to a control cohort matched by the estimated date of birth. Primary
endpoints: rate of spontaneous abortion and major malformations. Secondary
endpoints: preeclampsia, gestational age at birth, and birth weight.
RESULTS: Pregcy outcome of 323 women immunized with adjuvanted or
non-adjuvanted A(H1N1)v2009 influenza vaccines from 2009-09-28 to 2010-03-31
were compared to 1329 control subjects. The risk for spontaneous abortions (HR
0.89; 95% CI 0.36-2.19) and the rate of major malformations (all trimesters: OR
0.87; 95% CI 0.38-1.77; preconception and first trimester exposure: OR 0.79; 95%
CI 0.13-2.64) did not vary between the two cohorts. Furthermore, there was no
increase in preeclampsia, prematurity, and intrauterine growth retardation in
the vaccinated cohort.
CONCLUSION: The results of our study do not indicate a risk for the pregt
woman and the developing embryo/fetus after H1N1 vaccination. We provide and
apply methods novel in observational studies on pregcy outcome, especially if
a single dose exposure is investigated. The Influenza A H1N1 pandemic (A H1N1) occurred between June 2009 and August
2010. Although the pandemic is now over, the virus has emerged as the
predomit strain in the current seasonal influenza phase in the northern
hemisphere. The A H1N1 influenza is a novel strain of the influenza A virus and
is widely known as swine flu. The virus contains a mixture of genetic material
from human, pig and bird flu virus. It is a new variety of flu which people have
not had much immunity to. Much has been learnt from the Pandemic of 2009/2010
but the messages about vaccination and treatment seem to be taken slowly by the
clinical profession. Most people affected by the virus, including pregt
women, suffer a mild viral illness, and make a full recovery. The median
duration of illness is around seven days. This influenza typically affects the
younger age group i.e. from the ages of 5-65 years. Current experience shows
that the age group experiencing increased morbidity and mortality rates are in
those under 65 years of age. Pregt women, because of their altered immunity
and physiological adaptations, are at higher risk of developing pulmonary
complications, especially in the second and third trimesters. In the United
Kingdom, twelve maternal deaths were reported to be associated with the H1N1
virus during the pandemic and clear avoidable factors were identified (Modder,
Review of Maternal Deaths in the UK related to A H1N1 2009 influenza (CMACE).
www.cmace.org.uk, 2010). The pregcy outcomes were also poor for women who
were affected by the virus with a fivefold increase in the perinatal mortality
rate and threefold increase in the preterm delivery rate (Yates et al. Health
Technol Assess 14(34):109-182, 2010). There continues to be a low uptake of the
flu vaccine and commencement of antiviral treatment for pregt women. BACKGROUND: Pregt women were at increased risk for serious outcomes of 2009
pandemic influenza A virus subtype H1N1 (influenza A[H1N1]pdm09) infection, but
little is known about the overall impact of the pandemic on neonatal and
maternal outcomes.
METHODS: We identified live births that occurred from 1 July 2008 through 31 May
2010 in 5 Kaiser Permanente regions. Pregt women were considered to have
influenza if they had a positive result of a laboratory test for influenza virus
or if they received a diagnosis of influenza during a period in which seasonal
influenza virus or A(H1N1)pdm09 was the predomit circulating virus.
RESULTS: There were 111 158 births from 109 015 pregcies involving 107 889
mothers; 368 pregt women (0.3%) received a diagnosis of influenza due to
seasonal virus, and 959 (0.9%) received a diagnosis of influenza due to
A(H1N1)pdm09; 107 688 did not receive an influenza diagnosis. Pregt women
with influenza due to A(H1N1)pdm09 were more likely than women with seasonal
influenza infection to be hospitalized within 30 days of the diagnosis (27% vs
12%; odds ratio [OR], 2.84 [95% confidence interval {CI}, 2.01-4.02]). Pregt
women with A(H1N1)pdm09 who started antiviral treatment ≥2 days after the
diagnosis were significantly more likely to be hospitalized than those who
started antiviral treatment <2 days after diagnosis (OR, 3.43 [95% CI,
1.55-7.56]). Mothers with seasonal influenza virus infection had an increased
risk for having a small-for-gestational-age infant (OR, 1.59 [95% CI,
1.15-2.20]).
CONCLUSIONS: In this large, geographically diverse population, A(H1N1)pdm09
infection increased the risk for hospitalization during pregcy. Late
initiation of antiviral treatment was also associated with an increased risk for
hospitalization. Although influenza is usually a self-limited disease, patients who develop
complications are at increased risk of hospitalization, intensive care unit
admission and death. Since preventive and early therapeutic measures should be
prioritized in higher risk patients, identification of the risk factors for
severe infection is important from a public health perspective. Risk factors for
complications in pandemics may show some differences with regard to seasonal
influenza. During the influenza A(H1N1)pmd09 pandemic, although many cases
occurred in younger adults, the risk factors identified for severe infections
and complications were similar to those for seasonal influenza, including
chronic respiratory, renal, liver, and heart diseases. Aged patients, although
less frequently affected, were also at higher risk. Obesity, and particularly
morbid obesity (>40 body mass index) has been noted as a significant risk factor
for severe disease in the 2009 influenza pandemic. Some interesting recent
studies provide insights into the biological reasons behind the poor outcomes in
morbidly obese patients. In terms of pregcy, the studies have shown
contradictory results due to variations in methodology and medical care.
However, it seems that pregcy, particularly during the third trimester,
increases the risk of complications, and that early antiviral treatment is
associated with improved outcomes. OBJECTIVE: To evaluate associations between laboratory-confirmed 2009 H1N1
influenza infection and obstetric and neonatal outcomes.
STUDY DESIGN: A multicenter cohort study was performed comparing
laboratory-confirmed cases of 2009 H1N1 infection during pregcy (N=142) with
matched controls (N=710). Subanalysis was also performed comparing severely
infected (hospitalized) women with controls.
RESULT: No outcome differences were noted in comparing all women with H1N1 with
controls. Women with severe infection had a higher incidence of delivering a
small for gestational age (SGA) infant: 18.8% (6/32) versus 7.4% (52/707),
adjusted odds ratio 2.35 (95% confidence interval 1.03, 5.36, P=0.02). Mean
birth weight was 3013.0 g among severely infected women and 3223.3 g in controls
(P=0.08), and incidence of preterm delivery was 25.0% (8/32) and 11.6% (82/710)
(P=0.08), respectively.
CONCLUSION: Pregt women with mild clinical illness secondary to 2009 H1N1
were not at a greater risk of adverse pregcy outcomes. However, severely
infected women were more likely to deliver SGA infants. |
Are long non coding RNAs as conserved in sequence as protein coding genes? | No. Most long non coding RNAs (lncRNAs) are under lower sequence constraints than protein-coding genes. | Experimental evidence suggests that half or more of the mammalian transcriptome
consists of noncoding RNA. Noncoding RNAs are divided into short noncoding RNAs
(including microRNAs) and long noncoding RNAs (lncRNAs). We defined
complementary DNAs (cDNAs) lacking any positive-strand open reading frames
(ORFs) longer than 30 amino acids, as well as cDNAs lacking any evidence of
interspecies conservation of their longer-than-30-amino acid ORFs, as noncoding.
We have identified 5446 lncRNA genes in the human genome from approximately
24,000 full-length cDNAs, using our new ORF-prediction pipeline. We combined
them nonredundantly with lncRNAs from four published sources to derive 6736
lncRNA genes. In an effort to distinguish standalone and antisense lncRNA genes
from database artifacts, we stratified our catalog of lncRNAs according to the
distance between each lncRNA gene candidate and its nearest known protein-coding
gene. We concurrently examined the protein-coding capacity of known genes
overlapping with lncRNAs. Remarkably, 62% of known genes with "hypothetical
protein" names actually lacked protein-coding capacity. This study has greatly
expanded the known human lncRNA catalog, increased its accuracy through manual
annotation of cDNA-to-genome alignments, and revealed that a large set of
hypothetical-protein genes in GenBank lacks protein-coding capacity. In
addition, we have developed, independently of existing NCBI tools, command-line
programs with high-throughput ORF-finding and BLASTP-parsing functionality,
suitable for future automated assessments of protein-coding capacity of novel
transcripts. BACKGROUND: Long considered to be the building block of life, it is now apparent
that protein is only one of many functional products generated by the eukaryotic
genome. Indeed, more of the human genome is transcribed into noncoding sequence
than into protein-coding sequence. Nevertheless, whilst we have developed a deep
understanding of the relationships between evolutionary constraint and function
for protein-coding sequence, little is known about these relationships for
non-coding transcribed sequence. This dearth of information is partially
attributable to a lack of established non-protein-coding RNA (ncRNA) orthologs
among birds and mammals within sequence and expression databases.
RESULTS: Here, we performed a multi-disciplinary study of four highly conserved
and brain-expressed transcripts selected from a list of mouse long intergenic
noncoding RNA (lncRNA) loci that generally show pronounced evolutionary
constraint within their putative promoter regions and across exon-intron
boundaries. We identify some of the first lncRNA orthologs present in birds
(chicken), marsupial (opossum), and eutherian mammals (mouse), and investigate
whether they exhibit conservation of brain expression. In contrast to
conventional protein-coding genes, the sequences, transcriptional start sites,
exon structures, and lengths for these non-coding genes are all highly variable.
CONCLUSIONS: The biological relevance of lncRNAs would be highly questionable if
they were limited to closely related phyla. Instead, their preservation across
diverse amniotes, their apparent conservation in exon structure, and
similarities in their pattern of brain expression during embryonic and early
postnatal stages together indicate that these are functional RNA molecules, of
which some have roles in vertebrate brain development. Large numbers of long RNAs with little or no protein-coding potential [long
noncoding RNAs (lncRNAs)] are being identified in eukaryotes. In parallel,
increasing data describing the expression profiles, molecular features and
functions of individual lncRNAs in a variety of systems are accumulating. To
enable the systematic compilation and updating of this information, we have
developed a database (lncRNAdb) containing a comprehensive list of lncRNAs that
have been shown to have, or to be associated with, biological functions in
eukaryotes, as well as messenger RNAs that have regulatory roles. Each entry
contains referenced information about the RNA, including sequences, structural
information, genomic context, expression, subcellular localization,
conservation, functional evidence and other relevant information. lncRNAdb can
be searched by querying published RNA names and aliases, sequences, species and
associated protein-coding genes, as well as terms contained in the annotations,
such as the tissues in which the transcripts are expressed and associated
diseases. In addition, lncRNAdb is linked to the UCSC Genome Browser for
visualization and Noncoding RNA Expression Database (NRED) for expression
information from a variety of sources. lncRNAdb provides a platform for the
ongoing collation of the literature pertaining to lncRNAs and their association
with other genomic elements. lncRNAdb can be accessed at:
http://www.lncrnadb.org/. Thousands of long noncoding RNAs (lncRNAs) have been found in vertebrate
animals, a few of which have known biological roles. To better understand the
genomics and features of lncRNAs in invertebrates, we used available RNA-seq,
poly(A)-site, and ribosome-mapping data to identify lncRNAs of Caenorhabditis
elegans. We found 170 long intervening ncRNAs (lincRNAs), which had single- or
multiexonic structures that did not overlap protein-coding transcripts, and
about sixty antisense lncRNAs (ancRNAs), which were complementary to
protein-coding transcripts. Compared to protein-coding genes, the lncRNA genes
tended to be expressed in a stage-dependent manner. Approximately 25% of the
newly identified lincRNAs showed little signal for sequence conservation and
mapped antisense to clusters of endogenous siRNAs, as would be expected if they
serve as templates and targets for these siRNAs. The other 75% tended to be more
conserved and included lincRNAs with intriguing expression and sequence features
associating them with processes such as dauer formation, male identity, sperm
formation, and interaction with sperm-specific mRNAs. Our study provides a
glimpse into the lncRNA content of a nonvertebrate animal and a resource for
future studies of lncRNA function. BACKGROUND: The HOX gene clusters are thought to be highly conserved amongst
mammals and other vertebrates, but the long non-coding RNAs have only been
studied in detail in human and mouse. The sequencing of the kangaroo genome
provides an opportunity to use comparative analyses to compare the HOX clusters
of a mammal with a distinct body plan to those of other mammals.
RESULTS: Here we report a comparative analysis of HOX gene clusters between an
Australian marsupial of the kangaroo family and the eutherians. There was a
strikingly high level of conservation of HOX gene sequence and structure and
non-protein coding genes including the microRNAs miR-196a, miR-196b, miR-10a and
miR-10b and the long non-coding RNAs HOTAIR, HOTAIRM1 and HOXA11AS that play
critical roles in regulating gene expression and controlling development. By
microRNA deep sequencing and comparative genomic analyses, two conserved
microRNAs (miR-10a and miR-10b) were identified and one new candidate microRNA
with typical hairpin precursor structure that is expressed in both fibroblasts
and testes was found. The prediction of microRNA target analysis showed that
several known microRNA targets, such as miR-10, miR-414 and miR-464, were found
in the tammar HOX clusters. In addition, several novel and putative miRNAs were
identified that originated from elsewhere in the tammar genome and that target
the tammar HOXB and HOXD clusters.
CONCLUSIONS: This study confirms that the emergence of known long non-coding
RNAs in the HOX clusters clearly predate the marsupial-eutherian divergence 160
Ma ago. It also identified a new potentially functional microRNA as well as
conserved miRNAs. These non-coding RNAs may participate in the regulation of HOX
genes to influence the body plan of this marsupial. A large proportion of functional sequence within mammalian genomes falls outside
protein-coding exons and can be transcribed into long RNAs. However, the roles
in mammalian biology of long noncoding RNA (lncRNA) are not well understood. Few
lncRNAs have experimentally determined roles, with some of these being
lineage-specific. Determining the extent by which transcription of lncRNA loci
is retained or lost across multiple evolutionary lineages is essential if we are
to understand their contribution to mammalian biology and to lineage-specific
traits. Here, we experimentally investigated the conservation of lncRNA
expression among closely related rodent species, allowing the evolution of DNA
sequence to be uncoupled from evolution of transcript expression. We generated
total RNA (RNAseq) and H3K4me3-bound (ChIPseq) DNA data, and combined both to
construct catalogues of transcripts expressed in the adult liver of Mus musculus
domesticus (C57BL/6J), Mus musculus castaneus, and Rattus norvegicus. We
estimated the rate of transcriptional turnover of lncRNAs and investigated the
effects of their lineage-specific birth or death. LncRNA transcription showed
considerably greater gain and loss during rodent evolution, compared with
protein-coding genes. Nucleotide substitution rates were found to mirror the in
vivo transcriptional conservation of intergenic lncRNAs between rodents: only
the sequences of noncoding loci with conserved transcription were constrained.
Finally, we found that lineage-specific intergenic lncRNAs appear to be
associated with modestly elevated expression of genomically neighbouring
protein-coding genes. Our findings show that nearly half of intergenic lncRNA
loci have been gained or lost since the last common ancestor of mouse and rat,
and they predict that such rapid transcriptional turnover contributes to the
evolution of tissue- and lineage-specific gene expression. The human genome contains many thousands of long noncoding RNAs (lncRNAs). While
several studies have demonstrated compelling biological and disease roles for
individual examples, analytical and experimental approaches to investigate these
genes have been hampered by the lack of comprehensive lncRNA annotation. Here,
we present and analyze the most complete human lncRNA annotation to date,
produced by the GENCODE consortium within the framework of the ENCODE project
and comprising 9277 manually annotated genes producing 14,880 transcripts. Our
analyses indicate that lncRNAs are generated through pathways similar to that of
protein-coding genes, with similar histone-modification profiles, splicing
signals, and exon/intron lengths. In contrast to protein-coding genes, however,
lncRNAs display a striking bias toward two-exon transcripts, they are
predomitly localized in the chromatin and nucleus, and a fraction appear to
be preferentially processed into small RNAs. They are under stronger selective
pressure than neutrally evolving sequences-particularly in their promoter
regions, which display levels of selection comparable to protein-coding genes.
Importantly, about one-third seem to have arisen within the primate lineage.
Comprehensive analysis of their expression in multiple human organs and brain
regions shows that lncRNAs are generally lower expressed than protein-coding
genes, and display more tissue-specific expression patterns, with a large
fraction of tissue-specific lncRNAs expressed in the brain. Expression
correlation analysis indicates that lncRNAs show particularly striking positive
correlation with the expression of antisense coding genes. This GENCODE
annotation represents a valuable resource for future studies of lncRNAs. Tinkering with pre-existing genes has long been known as a major way to create
new genes. Recently, however, motherless protein-coding genes have been found to
have emerged de novo from ancestral non-coding DNAs. How these genes originated
is not well addressed to date. Here we identified 24 hominoid-specific de novo
protein-coding genes with precise origination timing in vertebrate phylogeny.
Strand-specific RNA-Seq analyses were performed in five rhesus macaque tissues
(liver, prefrontal cortex, skeletal muscle, adipose, and testis), which were
then integrated with public transcriptome data from human, chimpanzee, and
rhesus macaque. On the basis of comparing the RNA expression profiles in the
three species, we found that most of the hominoid-specific de novo
protein-coding genes encoded polyadenylated non-coding RNAs in rhesus macaque or
chimpanzee with a similar transcript structure and correlated tissue expression
profile. According to the rule of parsimony, the majority of these
hominoid-specific de novo protein-coding genes appear to have acquired a
regulated transcript structure and expression profile before acquiring coding
potential. Interestingly, although the expression profile was largely
correlated, the coding genes in human often showed higher transcriptional
abundance than their non-coding counterparts in rhesus macaque. The major
findings we report in this manuscript are robust and insensitive to the
parameters used in the identification and analysis of de novo genes. Our results
suggest that at least a portion of long non-coding RNAs, especially those with
active and regulated transcription, may serve as a birth pool for protein-coding
genes, which are then further optimized at the transcriptional level. Long noncoding RNAs (lncRNAs) have gained widespread attention in recent years
as a potentially new and crucial layer of biological regulation. lncRNAs of all
kinds have been implicated in a range of developmental processes and diseases,
but knowledge of the mechanisms by which they act is still surprisingly limited,
and claims that almost the entirety of the mammalian genome is transcribed into
functional noncoding transcripts remain controversial. At the same time, a small
number of well-studied lncRNAs have given us important clues about the biology
of these molecules, and a few key functional and mechanistic themes have begun
to emerge, although the robustness of these models and classification schemes
remains to be seen. Here, we review the current state of knowledge of the lncRNA
field, discussing what is known about the genomic contexts, biological
functions, and mechanisms of action of lncRNAs. We also reflect on how the
recent interest in lncRNAs is deeply rooted in biology's longstanding concern
with the evolution and function of genomes. Novel, profound and unexpected roles of long non-coding RNAs (lncRNAs) are
emerging in critical aspects of gene regulation. Thousands of lncRNAs have been
recently discovered in a wide range of mammalian systems, related to
development, epigenetics, cancer, brain function and hereditary disease. The
structural biology of these lncRNAs presents a brave new RNA world, which may
contain a diverse zoo of new architectures and mechanisms. While structural
studies of lncRNAs are in their infancy, we describe existing structural data
for lncRNAs, as well as crystallographic studies of other RNA machines and their
implications for lncRNAs. We also discuss the importance of dynamics in RNA
machine mechanism. Determining commonalities between lncRNA systems will help
elucidate the evolution and mechanistic role of lncRNAs in disease, creating a
structural framework necessary to pursue lncRNA-based therapeutics. |
Mutation of which gene is implicated in the Brain-lung-thyroid syndrome? | Brain-lung-thyroid syndrome (BLTS) characterized by congenital hypothyroidism, respiratory distress syndrome, and benign hereditary chorea is caused by thyroid transcription factor 1 (NKX2-1/TTF1) mutations. | Thyroid transcription factor 1 (NKX2-1/TITF1) mutations cause brain-lung-thyroid
syndrome, characterized by congenital hypothyroidism (CH), infant respiratory
distress syndrome (IRDS) and benign hereditary chorea (BHC). The objectives of
the present study were (i) detection of NKX2-1 mutations in patients with CH
associated with pneumopathy and/or BHC, (ii) functional analysis of new
mutations in vitro and (iii) description of the phenotypic spectrum of
brain-lung-thyroid syndrome. We identified three new heterozygous missense
mutations (L176V, P202L, Q210P), a splice site mutation (376-2A-->G), and one
deletion of NKX2-1 at 14q13. Functional analysis of the three missense mutations
revealed loss of transactivation capacity on the human thyroglobulin
enhancer/promoter. Interestingly, we showed that deficient transcriptional
activity of NKX2-1-P202L was completely rescued by cotransfected PAX8-WT,
whereas the synergistic effect was abolished by L176V and Q210P. The clinical
spectrum of 6 own and 40 published patients with NKX2-1 mutations ranged from
the complete triad of brain-lung-thyroid syndrome (50%), brain and thyroid
disease (30%), to isolated BHC (13%). Thyroid morphology was normal (55%) and
compensated hypothyroidism occurred in 61%. Lung disease occurred in 54% of
patients (IRDS at term 76%; recurrent pulmonary infections 24%). On follow-up,
20% developed severe chronic interstitial lung disease, and 16% died. In
conclusion, we describe five new NKX2.1 mutations with, for the first time,
complete rescue by PAX8 of the deficient transactivating capacity in one case.
Additionally, our review shows that the majority of affected patients display
neurological and/or thyroidal problems and that, although less frequent, lung
disease is responsible for a considerable mortality. Mutations in NKX2-1 cause neurological, pulmonary, and thyroid hormone
impairment. Recently, the disease was named brain-lung-thyroid syndrome. Here,
we report three patients with brain-lung-thyroid syndrome. All patients were
unable to walk until 24 months of age, and still have a staggering gait, without
mental retardation. They have also had choreoathetosis since early infancy.
Genetic analysis of NKX2-1 revealed a novel missense mutation (p.Val205Phe) in
two patients who were cousins and their maternal families, and a novel 2.6-Mb
deletion including NKX2-1 on chromosome 14 in the other patient. Congenital
hypothyroidism was not detected on neonatal screening in the patient with the
missense mutation, and frequent respiratory infections were observed in the
patient with the deletion in NKX2-1. Oral levodopa did not improve the gait
disturbance or involuntary movement. The results of (99m)Tc-ECD single-photon
emission computed tomography (ECD-SPECT) analyzed using the easy Z-score imaging
system showed decreased cerebral blood flow in the bilateral basal ganglia,
especially in the caudate nuclei, in all three patients, but no brain magnetic
resoce imaging (MRI) abnormalities. These brain nuclear image findings
indicate that NKX2-1 haploinsufficiency causes dysfunction of the basal ganglia,
especially the caudate nuclei, resulting in choreoathetosis and gait disturbance
in this disease. BACKGROUND: NKX2.1 mutations have been identified in patients displaying
complete or partial brain-lung-thyroid syndrome, which can include benign
hereditary chorea (BHC), hypothyroidism and/or lung disease.
AIMS AND METHODS: We evaluated the recently developed Multiplex
Ligation-dependent Probe Amplification (MLPA) method to assess the relative copy
number of genes. The goal was to determine if MLPA could improve, in addition to
direct sequencing, the detection rate of NKX2.1 mutations in a
phenotype-selected cohort of 24 patients affected by neurological, thyroid
and/or pulmonary disorders.
RESULTS: Direct sequencing revealed two heterozygous mutations. Using MLPA, we
identified two further heterozygous NKX2.1 gene deletions. MLPA increased the
detection rate by 50%. All patients with gene deletions identified were affected
by BHC and congenital hypothyroidism.
CONCLUSION: MLPA should be considered as a complementary tool in patients with
partial or total brain-lung-thyroid syndrome when direct sequencing failed to
identify NKX2.1 mutations. All patients with an NKX2.1 mutation had BHC and
congenital hypothyroidism, emphasizing the high prevalence of these signs
associated with defective NKX2.1 alleles. Brain-lung-thyroid syndrome (BLTS) characterized by congenital hypothyroidism,
respiratory distress syndrome, and benign hereditary chorea is caused by thyroid
transcription factor 1 (NKX2-1/TTF1) mutations. We report the clinical and
molecular characteristics of four cases presenting with primary hypothyroidism,
respiratory distress, and neurological disorder. Two of the four patients
presenting with the triad of BLTS had NKX2-1 mutations, and one of these NKX2-1
[c.890_896del (p.Ala327Glyfs*52)] is a novel variant. The third patient without
any identified NKX2-1 mutations was a carrier of mitochondrial mutation; this
raises the possibility of mitochondrial mutations contributing to thyroid
dysgenesis. Although rare, the triad of congenital hypothyroidism, neurological,
and respiratory signs is highly suggestive of NKX2-1 anomalies. Screening for
NKX2-1 mutations in patients with thyroid, lung, and neurological abnormalities
will enable a unifying diagnosis and genetic counseling for the affected
families. In addition, identification of an NKX2-1 defect would be helpful in
allaying the concerns about inadequate thyroxine supplementation as the cause of
neurological defects observed in some children with congenital hypothyroidism. AIM: Benign hereditary chorea is a domitly inherited, childhood-onset
hyperkinetic movement disorder characterized by non-progressive chorea and
variable degrees of thyroid and respiratory involvement. Loss-of-function
mutations in NKX2.1, a gene vital to the normal development and function of the
brain, lungs, and thyroid, have been identified in a number of individuals.
METHOD: Clinical data from individuals with benign hereditary chorea identified
through paediatric neurology services were collected in a standardized format.
The NKX2.1 gene was analysed by Sanger sequencing, multiplex ligation-dependent
probe amplification, and microarray analysis.
RESULTS: Six of our cohort were female and four male, median age at assessment
was 8 years 6 months (range 1 y 6 mo-18 y). We identified 10 probands with
NKX2.1 mutations; nine of these mutations are novel (including two whole-gene
deletions) and one has been previously reported. Of the 10 individuals, eight
presented with muscle hypotonia and four had evidence of hypothyroidism or
respiratory involvement. Only three out of the 10 individuals had the full triad
of 'brain-lung-thyroid syndrome' symptoms. Additional clinical characteristics
occurring in individual participants included growth hormone deficiency, pes
cavus, kyphosis, duplex kidney, and obsessive-compulsive disorder.
INTERPRETATION: Our data suggest that the neurological phenotype is prominent in
this condition and that many patients with benign hereditary chorea do not have
the classic triad of brain-lung-thyroid syndrome. The extended phenotype may
include obsessive-compulsive disorder and skeletal abnormalities. OBJECTIVES: To verify the involvement of NKX2-1 gene in infants with
brain-lung-thyroid (BLT) syndrome and hypothyroid phenotypes variable among
congenital hypothyroidism (CH) or idiopathic mild hypothyroidism (IMH) of
postnatal onset.
METHODS: The candidates were selected by a case-finding approach in 130 CH and
53 IMH infants. The NKX2-1 gene was analyzed by direct sequencing and multiplex
ligation-dependent probe amplification. The variants were studied in vitro, by
expression analyses and luciferase bioassay.
RESULTS: Four cases (3 CH and 1 IMH) consistent with BLT syndrome were
identified. Two children were affected with respiratory distress and CH, but
wild-type NKX2-1 gene. The remaining two presented choreic movements and no
pulmonary involvement, but discrepant thyroid phenotypes: one had severe CH with
lingual ectopy and the other one IMH with gland in situ. They were carriers of
new de novo heterozygous frameshift mutations of NKX2-1 (c.177delG and
c.153_166del14). The c.177delG leads to a prematurely truncated protein
(p.H60TfsX11) with undetectable activity in vitro. The c.153_166del14 leads to
the generation of an elongated aberrant protein (p.A52RfsX351) able to
translocate into the nucleus, but completely inactive on a responsive promoter.
CONCLUSIONS: Two novel heterozygous frameshift mutations of NKX2-1 were
identified in 2 cases selected on the basis of a BLT-like phenotype among 183
hypothyroid infants. The atypical hypothyroid phenotypes of these 2 children (CH
with lingual ectopy or IMH of postnatal onset) further expand the clinical
spectrum that can be associated with NKX2-1 mutations. |
What is clathrin? | Clathrin helps build small vesicles in order to safely transport molecules within and between cells. | Author information:
(1)Department of Cell Biology and Physiology, University of Pittsburgh School of
Medicine, Pittsburgh, Pennsylvania, USA. [email protected] Author information:
(1)Department of Cell Biology and Physiology, University of Pittsburgh School of
Medicine, Pittsburgh, Pennsylvania, United States of America. [email protected] Bacterial pathogens recruit clathrin upon interaction with host surface
receptors during infection. Here, using three different infection models, we
observed that host-pathogen interactions induce tyrosine phosphorylation of
clathrin heavy chain. This modification was critical for recruitment of actin at
bacteria-host adhesion sites during bacterial internalization or pedestal
formation. At the bacterial interface, clathrin assembled to form coated pits of
conventional size. Because such structures cannot internalize large particles
such as bacteria, we propose that during infection, clathrin-coated pits serve
as platforms to initiate actin rearrangements at bacteria-host adhesion sites.
We then showed that the clathrin-actin interdependency is initiated by Dab2 and
depends on the presence of clathrin light chain and its actin-binding partner
Hip1R, and that the fully assembled machinery can recruit Myosin VI. Together,
our study highlights a physiological role for clathrin heavy chain
phosphorylation and reinforces the increasingly recognized function of clathrin
in actin cytoskeletal organization in mammalian cells. The molecular mechanism responsible for capturing, sorting and retrieving
vesicle membrane proteins following triggered exocytosis is not understood. Here
we image the post-fusion release and then capture of a vesicle membrane protein,
the vesicular acetylcholine transporter, from single vesicles in living
neuroendocrine cells. We combine these measurements with super-resolution
interferometric photo-activation localization microscopy and electron
microscopy, and modelling to map the ometer-scale topography and architecture
of the structures responsible for the transporter's capture following
exocytosis. We show that after exocytosis, the transporter rapidly diffuses into
the plasma membrane, but most travels only a short distance before it is locally
captured over a dense network of membrane-resident clathrin-coated structures.
We propose that the extreme density of these structures acts as a short-range
diffusion trap. They quickly sequester diffusing vesicle material and limit its
spread across the membrane. This system could provide a means for
clathrin-mediated endocytosis to quickly recycle vesicle proteins in highly
excitable cells. Exposure to oparticles during pregcy is a public concern, because
oparticles may pass from the mother to the fetus across the placenta. The
purpose of this study was to determine the possible translocation pathway of
gold oparticles across the maternal-fetal barrier as well as the toxicity of
intravenously administered gold oparticles to the placenta and fetus.
Pregt ICR mice were intravenously injected with 0.01% of 20- and 50-nm gold
oparticle solutions on the 16th and 17th days of gestation. There was no sign
of toxic damage to the placentas as well as maternal and fetal organs of the
mice treated with 20- and 50-nm gold oparticles. ICP-MS analysis demonstrated
significant amounts of gold deposited in the maternal livers and placentas, but
no detectable level of gold in the fetal organs. However, electron microscopy
demonstrated an increase of endocytic vesicles in the cytoplasm of
syncytiotrophoblasts and fetal endothelial cells in the maternal-fetal barrier
of mice treated with gold oparticles. Clathrin immunohistochemistry and
immunoblotting showed increased immunoreactivity of clathrin protein in the
placental tissues of mice treated with 20- and 50-nm gold oparticles;
clathrin immunopositivity was observed in syncytiotrophoblasts and fetal
endothelial cells. In contrast, caveolin-1 immunopositivity was observed
exclusively in the fetal endothelium. These findings suggested that intravenous
administration of gold oparticles may upregulate clathrin- and
caveolin-mediated endocytosis at the maternal-fetal barrier in mouse placenta. Clathrin-coated vesicles (CCVs) are formed at the plasma membrane and act as
vectors for endocytosis. They also assemble at the trans-Golgi network (TGN),
but their exact function at this organelle is unclear. Recent studies have
examined the effects on vacuolar and secretory protein transport of knockout
mutations of the adaptor protein 1 (AP1) μ-adaptin subunit AP1M, but these
investigations do not clarify the situation. These mutations lead to the
abrogation of multiple trafficking pathways at the TGN and cannot be used as
evidence in favour of CCVs being agents for receptor-mediated export of vacuolar
proteins out of the TGN. This transport process could just as easily occur
through the maturation of the TGN into intermediate compartments that
subsequently fuse with the vacuole. Author information:
(1)Department of Cellular and Physiological Sciences, Faculty of Medicine,
University of British Columbia, Vancouver, BC Canada V6T 1Z3. Electronic
address: [email protected].
(2)Department of Cellular and Physiological Sciences, Faculty of Medicine,
University of British Columbia, Vancouver, BC Canada V6T 1Z3. Electronic
address: [email protected].
(3)Department of Cellular and Physiological Sciences, Faculty of Medicine,
University of British Columbia, Vancouver, BC Canada V6T 1Z3. Electronic
address: [email protected].
(4)Department of Radiology, College of Human Medicine, Michigan State
University, Grand Rapids, MI 49503, USA. Electronic address:
J'[email protected]. We reported the first small molecule inhibitors of the interaction between the
clathrin N-terminal domain (TD) and endocyctic accessory proteins (i.e.,
clathrin inhibition1). Initial screening of a ∼17 000 small molecule ChemBioNet
library identified 1. Screening of an existing in-house propriety library
identified four substituted 1,8-napthalimides as ∼80-120 μM clathrin inhibitors.
Focused library development gave 3-sulfo-N-(4-aminobenzyl)-1,8-naphthalimide,
potassium salt (18, IC50 ≈ 18 μM). A second library targeting the 4-aminobenzyl
moiety was developed, and four analogues displayed comparable activity (26, 27,
28, 34 with IC50 values of 22, 16, 15, and 15 μM respectively) with a further
four (24, 25, 32, 33) more active than 18 with IC50 values of 10, 6.9, 12, and
10 μM, respectively. Docking studies rationalized the structure-activity
relationship (SAR) with the biological data. 3-Sulfo-N-benzyl-1,8-naphthalimide,
potassium salt (25) with an IC50 ≈ 6.9 μM, is the most potent clathrin terminal
domain-amphiphysin inhibitor reported to date. Macromolecules gain access to the cytoplasm of eukaryotic cells using one of
several ways of which clathrin-dependent endocytosis is the most researched.
Although the mechanism of clathrin-mediated endocytosis is well understood in
general, novel adaptor proteins that play various roles in ensuring specific
regulation of the mentioned process are being discovered all the time. This
review provides a detailed account of the mechanism of clathrin-mediated
internalization of activated G protein-coupled receptors, as well as a
description of the major proteins involved in this process. Clathrin-mediated endocytosis is a central and well-studied trafficking process
in eukaryotic cells. How this process is initiated is likely to be a critical
point in regulating endocytic activity spatially and temporally, but the
underlying mechanisms are poorly understood. During the early stages of
endocytosis three components-adaptor and accessory proteins, cargo, and
lipids-come together at the plasma membrane to begin the formation of
clathrin-coated vesicles. Although different models have been proposed, there is
still no clear picture of how these three components cooperate to initiate
endocytosis, which may indicate that there is some flexibility underlying this
important event. |
What are the main results of PRKAR1A Knockdown? | Suppression of protein kinase A regulatory subunit 1 alpha (PRKAR1A) has been proven to inhibit cholangiocarcinoma (CCA) cell growth and enhance apoptosis. Also, Knockdown of the cAMP-dependent protein kinase (PKA) Type Ialpha regulatory subunit in mouse oocytes disrupts meiotic arrest and results in meiotic spindle defects. | In mammalian oocytes, cyclic AMP-dependent protein kinase (PKA) is responsible
for maintaining meiotic arrest. We examined the role of the predomit
regulatory subunit, RIalpha in regulating PKA activity during mouse oocyte
maturation by knocking down the protein levels using an RNA interference
approach. In oocytes in which RIalpha protein was reduced to non-detectable
levels, compensatory decreases were also observed in the RIIalpha and catalytic
(Calpha) subunit levels. These oocytes resumed meiosis, despite culture under
conditions that maintain elevated intracellular cAMP levels, suggesting that the
remaining Calpha was not sufficient to maintain meiotic arrest. The resulting
eggs, however, displayed meiotic spindle abnormalities and abnormal cleavage
planes leading to extrusion of large polar bodies. These results demonstrate
that RIalpha is required for regulating PKA activity in maturing oocytes and
that compensatory upregulation of RII does not occur. Furthermore, we implicate
PKA as a modulator of spindle morphology and function during meiosis. Suppression of protein kinase A regulatory subunit 1 alpha (PRKAR1A) has been
proven to inhibit cholangiocarcinoma (CCA) cell growth and enhance apoptosis. In
the present study, we aimed to determine synergistic and/or additive effects of
chemotherapeutic agents, including protein kinase inhibitors (i.e. sorafenib,
sunitinib, gefitinib, Met inhibitor) and conventional chemotherapeutic drugs
(i.e. 5-fluorouracil, doxorubicin, paclitaxel, gemcitabine), in PRKARIA
knockdown CCA cell lines. The results revealed that PRKAR1A suppressed CCA cell
lines demonstrated enhanced sensitivity to some chemotherapeutic drugs when
compared to control cells. Moreover, PRKAR1A knockdown in combination with
either sorafenib or 5-fluorouracil increased apoptotic effects on CCA cell
lines. Therefore, selective inhibition of PRKAR1A appears to enhance the growth
inhibitory effects of chemotherapeutic drugs as well as induce apoptotic cell
death. Our findings suggest that additional suppression of PRKAR1A expression
may increase the efficacy of conventional CCA chemotherapeutic treatment.
Clinical studies in CCA patients now need to be conducted. Carney complex (CNC) is a hereditary disease associating cardiac myxoma, spotty
skin pigmentation and endocrine overactivity. CNC is caused by inactivating
mutations in the PRKAR1A gene encoding PKA type I alpha regulatory subunit
(RIα). Although PKA activity is enhanced in CNC, the mechanisms linking PKA
dysregulation to endocrine tumorigenesis are poorly understood. In this study,
we used Förster resoce energy transfer (FRET)-based sensors for cAMP and PKA
activity to define the role of RIα in the spatiotemporal organization of the
cAMP/PKA pathway. RIα knockdown in HEK293 cells increased basal as well as
forskolin or prostaglandin E1 (PGE1)-stimulated total cellular PKA activity as
reported by western blots of endogenous PKA targets and the FRET-based global
PKA activity reporter, AKAR3. Using variants of AKAR3 targeted to subcellular
compartments, we identified similar increases in the response to PGE1 in the
cytoplasm and at the outer mitochondrial membrane. In contrast, at the plasma
membrane, the response to PGE1 was decreased along with an increase in basal
FRET ratio. These results were confirmed by western blot analysis of basal and
PGE1-induced phosphorylation of membrane-associated vasodilator-stimulated
phosphoprotein. Similar differences were observed between the cytoplasm and the
plasma membrane in human adrenal cells carrying a RIα inactivating mutation. RIα
inactivation also increased cAMP in the cytoplasm, at the outer mitochondrial
membrane and at the plasma membrane, as reported by targeted versions of the
cAMP indicator Epac1-camps. These results show that RIα inactivation leads to
multiple, compartment-specific alterations of the cAMP/PKA pathway revealing new
aspects of signaling dysregulation in tumorigenesis. |
Is TENS machine effective in pain? | Transcutaneous electrical nerve stimulation is widely used in pain management | The hypoalgesic effect of transcutaneous electrical nerve stimulation (TENS) at
2 different frequencies was assessed under double-blind conditions using a
standardised form of the submaximum effort tourniquet technique. For the purpose
of pain induction, 32 healthy naive female subjects attended on 2 occasions, the
first during which baseline data were obtained and the second during which the
women were randomly allocated to 1 of 4 groups: Control, Placebo, TENS-1 (110
Hz) or TENS-2 (4 Hz). In the treatment groups, 2 hydrogel electrodes were
positioned over Erb's point and lateral to C6 and C7 vertebral spines. A TENS
machine was applied for 10 min before the cuff was inflated and remained on for
the duration of the pain procedure (12 min). Pain was measured using visual
analogue scales (VAS) and the McGill Pain Questionnaire (MPQ) to assess 'current
pain intensity' and 'worst pain experienced', respectively. Analysis of VAS
scores showed significant differences between groups (ANOVA, P = 0.02), with the
TENS-2 group showing a greater hypoalgesic effect than the other groups.
One-factor ANOVA showed no significant differences in MPQ scores between groups.
The results of this study have provided evidence of the hypoalgesic effects of
TENS upon experimental ischaemic pain which were found to be frequency specific
with the lower frequency used here (4 Hz) demonstrating the only significant
effect. Transcutaneous electrical nerve stimulation is widely used in pain management
but its effectiveness depends on the stimulation being targeted appropriately.
This article, the second in a two-part series, outlines how to set up and use a
TENS machine to achieve the most effective results. |
Is there any algorithm for enhancer identification from chromatin state? | yes | The chemical modification of histones at specific DNA regulatory elements is
linked to the activation, inactivation and poising of genes. A number of tools
exist to predict enhancers from chromatin modification maps, but their practical
application is limited because they either (i) consider a smaller number of
marks than those necessary to define the various enhancer classes or (ii) work
with an excessive number of marks, which is experimentally unviable. We have
developed a method for chromatin state detection using support vector machines
in combination with genetic algorithm optimization, called ChromaGenSVM.
ChromaGenSVM selects optimum combinations of specific histone epigenetic marks
to predict enhancers. In an independent test, ChromaGenSVM recovered 88% of the
experimentally supported enhancers in the pilot ENCODE region of interferon
gamma-treated HeLa cells. Furthermore, ChromaGenSVM successfully combined the
profiles of only five distinct methylation and acetylation marks from ChIP-seq
libraries done in human CD4(+) T cells to predict ∼21,000 experimentally
supported enhancers within 1.0 kb regions and with a precision of ∼90%, thereby
improving previous predictions on the same dataset by 21%. The combined results
indicate that ChromaGenSVM comfortably outperforms previously published methods
and that enhancers are best predicted by specific combinations of histone
methylation and acetylation marks. Transcriptional enhancers play critical roles in regulation of gene expression,
but their identification in the eukaryotic genome has been challenging.
Recently, it was shown that enhancers in the mammalian genome are associated
with characteristic histone modification patterns, which have been increasingly
exploited for enhancer identification. However, only a limited number of cell
types or chromatin marks have previously been investigated for this purpose,
leaving the question uswered whether there exists an optimal set of histone
modifications for enhancer prediction in different cell types. Here, we address
this issue by exploring genome-wide profiles of 24 histone modifications in two
distinct human cell types, embryonic stem cells and lung fibroblasts. We
developed a Random-Forest based algorithm, RFECS (Random Forest based Enhancer
identification from Chromatin States) to integrate histone modification profiles
for identification of enhancers, and used it to identify enhancers in a number
of cell-types. We show that RFECS not only leads to more accurate and precise
prediction of enhancers than previous methods, but also helps identify the most
informative and robust set of three chromatin marks for enhancer prediction. |
Which enzyme is targeted by the drug Imetelstat? | Imetelstat sodium (GRN163L), is a 13-mer oligonucleotide N3'→P5' thio-phosphoramidate lipid conjugate, which represents the latest generation of telomerase inhibitors targeting the template region of the human functional telomerase RNA subunit. In preclinical trials, this compound has been found to inhibit telomerase activity in multiple cancer cell lines, as well as in vivo xenograft mouse models. | Telomeres and telomerase play essential roles in the regulation of the lifespan
of human cells. While normal human somatic cells do not or only transiently
express telomerase and therefore shorten their telomeres with each cell
division, most human cancer cells typically express high levels of telomerase
and show unlimited cell proliferation. High telomerase expression allows cells
to proliferate and expand long-term and therefore supports tumor growth. Owing
to the high expression and its role, telomerase has become an attractive
diagnostic and therapeutic cancer target. Imetelstat (GRN163L) is a potent and
specific telomerase inhibitor and so far the only drug of its class in clinical
trials. Here, we report on the structure and the mechanism of action of
imetelstat as well as about the preclinical and clinical data and future
prospects using imetelstat in cancer therapy. Nucleic acids analogues, i.e., oligonucleotide N3'-->P5' phosphoramidates and
N3'-->P5' thio-phosphoramidates, containing 3'-amino-3'-deoxy nucleosides with
various 2'-substituents were synthesized and extensively studied. These
compounds resist nuclease hydrolysis and form stable duplexes with complementary
native phosphodiester DNA and, particularly, RNA strands. An increase in
duplexes' melting temperature, DeltaT(m), relative to their phosphodiester
counterparts, reaches 2.2-4.0 degrees per modified nucleoside. 2'-OH-
(RNA-like), 2'-O-Me-, and 2'-ribo-F-nucleoside substitutions result in the
highest degree of duplex stabilization. Moreover, under close to physiological
salt and pH conditions, the 2'-deoxy- and 2'-fluoro-phosphoramidate compounds
form extremely stable triple-stranded complexes with either single- or
double-stranded phosphodiester DNA oligonucleotides. Melting temperature, T(m),
of these triplexes exceeds T(m) values for the isosequential phosphodiester
counterparts by up to 35 degrees . 2'-Deoxy-N3'-->P5' phosphoramidates adopt
RNA-like C3'-endo or N-type nucleoside sugar-ring conformations and hence can be
used as stable RNA mimetics. Duplexes formed by 2'-deoxy phosphoramidates with
complementary RNA strands are not substrates for RNase H-mediated cleavage in
vitro. Oligonucleotide phosphoramidates and especially thio-phosphoramidates
conjugated with lipid groups are cell-permeable and demonstrate high biological
target specific activity in vitro. In vivo, these compounds show good
bioavailability and efficient biodistribution to all major organs, while
exerting acceptable toxicity at therapeutically relevant doses. Short
oligonucleotide N3'-->P5' thio-phosphoramidate conjugated to 5'-palmitoyl group,
designated as GRN163L (Imetelstat), was recently introduced as a potent human
telomerase inhibitor. GRN163L is not an antisense agent; it is a direct
competitive inhibitor of human telomerase, which directly binds to the active
site of the enzyme and thus inhibits its activity. This compound is currently in
multiple Phase-I and Phase-I/II clinical trials as potential broad-spectrum
anticancer agent. Cancer stem cells (CSC) are rare drug-resistant cancer cell subsets proposed to
be responsible for the maintece and recurrence of cancer and metastasis.
Telomerase is constitutively active in both bulk tumor cell and CSC populations
but has only limited expression in normal tissues. Thus, inhibition of
telomerase has been shown to be a viable approach in controlling cancer growth
in nonclinical studies and is currently in phase II clinical trials. In this
study, we investigated the effects of imetelstat (GRN163L), a potent telomerase
inhibitor, on both the bulk cancer cells and putative CSCs. When breast and
pancreatic cancer cell lines were treated with imetelstat in vitro, telomerase
activity in the bulk tumor cells and CSC subpopulations were inhibited.
Additionally, imetelstat treatment reduced the CSC fractions present in the
breast and pancreatic cell lines. In vitro treatment with imetelstat, but not
control oligonucleotides, also reduced the proliferation and self-renewal
potential of MCF7 mammospheres and resulted in cell death after <4 weeks of
treatment. In vitro treatment of PANC1 cells showed reduced tumor engraftment in
nude mice, concomitant with a reduction in the CSC levels. Differences between
telomerase activity expression levels or telomere length of CSCs and bulk tumor
cells in these cell lines did not correlate with the increased sensitivity of
CSCs to imetelstat, suggesting a mechanism of action independent of telomere
shortening for the effects of imetelstat on the CSC subpopulations. Our results
suggest that imetelstat-mediated depletion of CSCs may offer an alternative
mechanism by which telomerase inhibition may be exploited for cancer therapy. Specific information about how telomerase acts in vivo is necessary for
understanding telomere dynamics in human tumor cells. Our results imply that,
under homeostatic telomere length-maintece conditions, only one molecule of
telomerase acts at each telomere during every cell division and processively
adds ∼60 nt to each end. In contrast, multiple molecules of telomerase act at
each telomere when telomeres are elongating (nonequilibrium conditions).
Telomerase extension is less processive during the first few weeks following the
reversal of long-term treatment with the telomerase inhibitor Imetelstat
(GRN163L), a time when Cajal bodies fail to deliver telomerase RNA to telomeres.
This result implies that processing of telomerase by Cajal bodies may affect its
processivity. Overexpressed telomerase is also less processive than the
endogenously expressed telomerase. These findings reveal two major distinct
extension modes adopted by telomerase in vivo. Breast cancer is a progressive and potentially fatal disease that affects women
of all ages. Like all progressive diseases, early and reliable diagnosis is the
key for successful treatment and annihilation. Biomarkers serve as indicators of
pathological, physiological, or pharmacological processes. Her2/neu, CA15.3,
estrogen receptor (ER), progesterone receptor (PR), and cytokeratins are
biomarkers that have been approved by the Food and Drug Administration for
disease diagnosis, prognosis, and therapy selection. The structural and
functional complexity of protein biomarkers and the heterogeneity of the breast
cancer pathology present challenges to the scientific community. Here we review
estrogen receptor-related putative breast cancer biomarkers, including those of
putative breast cancer stem cells, a minor population of estrogen receptor
negative tumor cells that retain the stem cell property of self-renewal. We also
review a few promising cytoskeleton targets for ER alpha negative breast cancer. Recently, there has been renewed interest in the role of tumor stem cells (TSCs)
in tumorigenesis, chemoresistance, and relapse of maligt tumors including
osteosarcoma. The potential exists to improve osteosarcoma treatment through
characterization of TSCs and identification of therapeutic targets. Using
transcriptome, proteome, immunophenotyping for cell-surface markers, and
bioinformatic analyses, heterogeneous expression of previously reported TSC or
osteosarcoma markers, such as CD133, nestin, POU5F1 (OCT3/4), NANOG, SOX2, and
aldehyde dehydrogenase, among others, was observed in vitro. However,
consistently significantly lower CD326, CD24, CD44, and higher ABCG2 expression
in TSC-enriched as compared with un-enriched osteosarcoma cultures was observed.
In addition, consistently higher CBX3 expression in TSC-enriched osteosarcoma
cultures was identified. ABCA5 was identified as a putative biomarker of TSCs
and/or osteosarcoma. Lastly, in a high-throughput screen we identified
epigenetic (5-azacytidine), anti-microtubule (vincristine), and anti-telomerase
(3,11-difluoro-6,8,13-trimethyl- 8H-quino [4,3,2-kl] acridinium methosulfate;
RHPS4)-targeted therapeutic agents as candidates for TSC ablation in
osteosarcoma. INTRODUCTION: Physiologically relevant pre-clinical ex vivo models
recapitulating CNS tumor micro-environmental complexity will aid development of
biologically-targeted agents. We present comprehensive characterization of tumor
aggregates generated using the 3D Rotary Cell Culture System (RCCS).
METHODS: CNS cancer cell lines were grown in conventional 2D cultures and the
RCCS and comparison with a cohort of 53 pediatric high grade gliomas conducted
by genome wide gene expression and microRNA arrays, coupled with
immunohistochemistry, ex vivo magnetic resoce spectroscopy and drug
sensitivity evaluation using the histone deacetylase inhibitor, Vorinostat.
RESULTS: Macroscopic RCCS aggregates recapitulated the heterogeneous morphology
of brain tumors with a distinct proliferating rim, necrotic core and oxygen
tension gradient. Gene expression and microRNA analyses revealed significant
differences with 3D expression intermediate to 2D cultures and primary brain
tumors. Metabolic profiling revealed differential profiles, with an increase in
tumor specific metabolites in 3D. To evaluate the potential of the RCCS as a
drug testing tool, we determined the efficacy of Vorinostat against aggregates
of U87 and KNS42 glioblastoma cells. Both lines demonstrated markedly reduced
sensitivity when assaying in 3D culture conditions compared to classical 2D drug
screen approaches.
CONCLUSIONS: Our comprehensive characterization demonstrates that 3D RCCS
culture of high grade brain tumor cells has profound effects on the genetic,
epigenetic and metabolic profiles of cultured cells, with these cells residing
as an intermediate phenotype between that of 2D cultures and primary tumors.
There is a discrepancy between 2D culture and tumor molecular profiles, and RCCS
partially re-capitulates tissue specific features, allowing drug testing in a
more relevant ex vivo system. Many current chemotherapies function by damaging genomic DNA in rapidly dividing
cells ultimately leading to cell death. This therapeutic approach differentially
targets cancer cells that generally display rapid cell division compared to
normal tissue cells. However, although these treatments are initially effective
in arresting tumor growth and reducing tumor burden, resistance and disease
progression eventually occur. A major mechanism underlying this resistance is
increased levels of cellular DNA repair. Most cells have complex mechanisms in
place to repair DNA damage that occurs due to environmental exposures or normal
metabolic processes. These systems, initially overwhelmed when faced with
chemotherapy induced DNA damage, become more efficient under constant selective
pressure and as a result chemotherapies become less effective. Thus, inhibiting
DNA repair pathways using target specific small molecule inhibitors may overcome
cellular resistance to DNA damaging chemotherapies. Non-homologous end joining a
major mechanism for the repair of double-strand breaks (DSB) in DNA is regulated
in part by the serine/threonine kinase, DNA dependent protein kinase (DNA-PK).
The DNA-PK holoenzyme acts as a scaffold protein tethering broken DNA ends and
recruiting other repair molecules. It also has enzymatic activity that may be
involved in DNA damage signaling. Because of its' central role in repair of
DSBs, DNA-PK has been the focus of a number of small molecule studies. In these
studies specific DNA-PK inhibitors have shown efficacy in synergizing
chemotherapies in vitro. However, compounds currently known to specifically
inhibit DNA-PK are limited by poor pharmacokinetics: these compounds have poor
solubility and have high metabolic lability in vivo leading to short serum
half-lives. Future improvement in DNA-PK inhibition will likely be achieved by
designing new molecules based on the recently reported crystallographic
structure of DNA-PK. Computer based drug design will not only assist in
identifying novel functional moieties to replace the metabolically labile
morpholino group but will also facilitate the design of molecules to target the
DNA-PKcs/Ku80 interface or one of the autophosphorylation sites. Evidence continues to accumulate showing that tumors contain a minority
population of cells responsible for tumor initiation, growth, and recurrence.
These are termed "cancer stem cells" (CSCs). Functional assays have identified
the self-renewal and tumor-initiation capabilities of CSCs. Moreover, recent
studies have revealed that these CSCs is responsible for chemotherapy resistance
within a tumor. Several mechanisms of chemoresistance have been proposed,
including increased Wnt/β-catenin and Notch signaling, as well as high
expression levels of adenosine triphosphate-binding cassette transporters, an
active DNA repair capacity, and slow rate of self-renewal. Nanoscale
drug-delivery systems, which transport therapeutically active molecules, prolong
circulation, and improve biodistribution in the body, may allow more effective
and specific therapies to address the challenges posed by CSCs. In particular,
some ovehicles are being exploited for selective drug delivery to CSCs and
show promising results. In this review, we highlight the mechanisms of drug
resistance and the novel strategies using oscale drugs to eliminate CSCs. The emergence of diseases associated with telomere dysfunction, including AIDS,
aplastic anemia and pulmonary fibrosis, has bolstered interest in telomerase
activators. We report identification of a new small molecule activator, GRN510,
with activity ex vivo and in vivo. Using a novel mouse model, we tested the
potential of GRN510 to limit fibrosis induced by bleomycin in mTERT heterozygous
mice. Treatment with GRN510 at 10 mg/kg/day activated telomerase 2-4 fold both
in hematopoietic progenitors ex vivo and in bone marrow and lung tissue in vivo,
respectively. Telomerase activation was countered by co-treatment with
Imetelstat (GRN163L), a potent telomerase inhibitor. In this model of
bleomycin-induced fibrosis, treatment with GRN510 suppressed the development of
fibrosis and accumulation of senescent cells in the lung via a mechanism
dependent upon telomerase activation. Treatment of small airway epithelial cells
(SAEC) or lung fibroblasts ex vivo with GRN510 revealed telomerase activating
and replicative lifespan promoting effects only in the SAEC, suggesting that the
mechanism accounting for the protective effects of GRN510 against induced lung
fibrosis involves specific types of lung cells. Together, these results support
the use of small molecule activators of telomerase in therapies to treat
idiopathic pulmonary fibrosis. Telomerase comprises a reverse transcriptase and an internal RNA template that
maintains telomeres in many eukaryotes, and it is a well-validated cancer
target. However, there is a dearth of small molecules with efficacy against
human telomerase in vivo. We developed a surrogate yeast high-throughput assay
to identify human telomerase inhibitors. The reversibility of growth arrest
induced by active human telomerase was assessed against a library of 678
compounds preselected for bioactivity in S. cerevisiae. Four of eight compounds
identified reproducibly restored growth to strains expressing active human
telomerase, and three of these four compounds also specifically inhibited
purified human telomerase in vitro. These compounds represent probes for human
telomerase function, and potential entry points for development of lead
compounds against telomerase-positive cancers. Telomerase is a cellular ribonucleoprotein reverse transcriptase that plays a
crucial role in telomere maintece. This enzyme is expressed in approximately
90% of human tumors, but not in the majority of normal somatic cells. imetelstat
sodium (GRN163L), is a 13-mer oligonucleotide N3'→P5' thio-phosphoramidate lipid
conjugate, which represents the latest generation of telomerase inhibitors
targeting the template region of the human functional telomerase RNA (hTR)
subunit. In preclinical trials, this compound has been found to inhibit
telomerase activity in multiple cancer cell lines, as well as in vivo xenograft
mouse models. Currently, GRN163L is being investigated in several clinical
trials, including a phase II human non‑small cell lung cancer clinical trial, in
a maintece setting following standard doublet chemotherapy. In addition to
the inhibition of telomerase activity in cancer cell lines, GRN163L causes
morphological cell rounding changes, independent of hTR expression or telomere
length. This leads to the loss of cell adhesion properties; however, the
mechanism underlying this effect is not yet fully understood. In the present
study, we observed that GRN163L treatment leads to the loss of adhesion in A549
lung cancer cells, due to decreased E-cadherin expression, leading to the
disruption of the cytoskeleton through the alteration of actin, tubulin and
intermediate filament organization. Consequently, the less adherent cancer cells
initially cease to proliferate and are arrested in the G1 phase of the cell
cycle, accompanied by decreased matrix metalloproteinase-2 (MMP-2) expression.
These effects of GRN163L are independent of its telomerase catalytic activity
and may increase the therapeutic efficacy of GRN163L by decreasing the adhesion,
proliferation and metastatic potential of cancer cells in vivo. Tumor relapse after radiotherapy is a great concern in the treatment of
high-grade gliomas. Inhibition of the PI3-kinase/AKT pathway is known to
radiosensitize cancer cells and to delay their DNA repair after irradiation. In
this study, we show that the radiosensitization of CB193 and T98G, two
high-grade glioma cell lines, by the PI3K inhibitor LY294002, correlates with
the induction of G1 and G2/M arrest, but is inconsistently linked to a delayed
DNA double-strand break (DSBs) repair. The PI3K/AKT pathway has been shown to
activate radioprotective factors such as telomerase, whose inhibition may
contribute to the radiosensitization of cancer cells. However, we show that
radiation upregulates telomerase activity in LY-294002-treated glioma cells as
well as untreated controls, demonstrating a PI3K/AKT-independent pathway of
telomerase activation. Our study suggests that radiosensitizing strategies based
on PI3-kinase inhibition in high-grade gliomas may be optimized by additional
treatments targeting either telomerase activity or telomere maintece. In the era of new and mostly effective therapeutic protocols, multiple myeloma
still tends to be a hard-to-treat hematologic cancer. This hallmark of the
disease is in fact a sequel to drug resistant phenotypes persisting initially or
emerging in the course of treatment. Furthermore, the heterogeneous nature of
multiple myeloma makes treating patients with the same drug challenging because
finding a drugable oncogenic process common to all patients is not yet feasible,
while our current knowledge of genetic/epigenetic basis of multiple myeloma
pathogenesis is outstanding. Nonetheless, bone marrow microenvironment
components are well known as playing critical roles in myeloma tumor cell
survival and environment-mediated drug resistance happening most possibly in all
myeloma patients. Generally speaking, however; real mechanisms underlying drug
resistance in multiple myeloma are not completely understood. The present review
will discuss the latest findings and concepts in this regard. It reviews the
association of important chromosomal translocations, oncogenes (e.g. TP53)
mutations and deranged signaling pathways (e.g. NFκB) with drug response in
clinical and experimental investigations. It will also highlight how bone marrow
microenvironment signals (Wnt, Notch) and myeloma cancer stem cells could
contribute to drug resistance in multiple myeloma. |
Which interleukins are inhibited by Dupilumab? | Dupilumab, a fully human monoclonal antibody that blocks interleukin-4 and interleukin-13, has shown efficacy in patients with asthma and elevated eosinophil levels. | PURPOSE OF REVIEW: A small proportion of patients with asthma have severe
disease characterized by persistent airflow obstruction, airway
hyperresponsiveness and eosinophilic airway inflammation. This review focuses on
the clinical efficacy of inhibiting T helper 2-cytokine-mediated inflammatory
responses using monoclonal antibodies directed against immunoglobulin E (IgE),
interleukin (IL)-5, and IL-4/IL-13 in patients with severe refractory asthma.
RECENT FINDINGS: The heterogeneity of airway inflammation in severe asthma has
led to the recognition of multiple pathophysiologically distinct severe asthma
endotypes. Biomarkers are being developed and evaluated to identify these
endotypes and to guide the use of specific biologics in the appropriate patients
who remain uncontrolled on high doses of inhaled corticosteroids and long-acting
bronchodilators or oral corticosteroids. Examples include the efficacy of
omalizumab in patients with severe refractory atopic asthma characterized by
raised serum total IgE, mepolizumab, reslizumab, and benralizumab in patients
with recurrent eosinophilic exacerbations characterized by blood and sputum
eosinophilia despite high doses of corticosteroids, and lebrikizumab,
pitrakinra, dupilumab, and tralokinumab that target the IL-4/IL-13 signalling
pathways in patients with eosinophilic asthma or raised serum periostin.
SUMMARY: In severe refractory asthma, both an understanding of the underlying
pathophysiologic mechanisms driving airway inflammation and the identification
of appropriate biomarkers in individual patients are critical in guiding the use
of biologics and monoclonal antibodies that target the specific pathological
processes. Simultaneously with the steady progress towards a better knowledge of the
pathobiology of asthma, the potential usefulness of anticytokine therapies is
emerging as one of the key concepts in the newly developing treatments of this
widespread airway disease. In particular, given the key role played by
interleukin (IL)-4 and IL-13 in the pathophysiology of the most typical aspects
of asthma, such as chronic airway inflammation, tissue remodeling, and bronchial
hyperresponsiveness, these pleiotropic cytokines are now considered as suitable
therapeutic targets. Among the recently developed antiasthma biologic drugs, the
monoclonal antibody dupilumab is very promising because of its ability to
inhibit the biological effects of both IL-4 and IL-13. Indeed, dupilumab
prevents IL-4/13 interactions with the α-subunit of the IL-4 receptor complex. A
recent trial showed that in patients with difficult-to-control asthma, dupilumab
can markedly decrease asthma exacerbations and improve respiratory symptoms and
lung function; these effects were paralleled by significant reductions in
T-helper 2-associated inflammatory biomarkers. However, further larger and
longer trials are required to extend and validate these preliminary results, and
also to carefully study the safety and tolerability profile of dupilumab. BACKGROUND: Severe atopic dermatitis (AD) has a high unmet need for effective
and safe therapeutics. In early-phase trials, dupilumab, a fully human mAb
targeting IL-4 receptor α, markedly improved disease activity, but the effect of
IL-4/IL-13 blockade on AD at the molecular level has not been characterized.
OBJECTIVES: We sought to evaluate dupilumab modulation of the AD molecular
signature.
METHODS: We performed transcriptomic analyses of pretreatment and posttreatment
skin biopsy specimens from patients with moderate-to-severe AD treated weekly
with 150 or 300 mg of dupilumab or placebo.
RESULTS: Exacerbation of the AD transcriptome was observed in placebo-treated
patients. Dupilumab improved the AD signature in a dose-dependent manner.
Expression of genes upregulated in AD lesions decreased in patients treated with
dupilumab by 26% (95% CI, 21% to 32%) and 65% (95% CI, 60% to 71%) for treatment
with 150 and 300 mg, respectively. Genes downregulated in AD lesions increased
by 21% (95% CI, 16% to 27%) and 32% (95% CI, 26% to 37%) with dupilumab (150 and
300 mg, respectively). The molecular changes paralleled improvements in clinical
scores. A dupilumab treatment signature of 821 probes (>2-fold change, P < .05)
significantly modulated in the 300-mg dupilumab group at week 4 compared with
baseline was identified in this sample set. Significant (P < .05) decreases in
mRNA expression of genes related to hyperplasia (K16 and MKI67), T cells, and
dendritic cells (CD1b and CD1c) and potent inhibition of TH2-associated
chemokines (CCL17, CCL18, CCL22, and CCL26) were noted without significant
modulation of TH1-associated genes (IFNG).
CONCLUSIONS: This is the first report showing rapid improvement of the AD
molecular signature with targeted anti-IL-4 receptor α therapy. These data
suggest that IL-4 and IL-13 drive a complex, TH2-centered inflammatory axis in
patients with AD. An update to the atopic dermatitis (AD) practice parameter was published in 2013
using an established grading system for determining category of evidence and
strength of recommendation. Since the previous update in 2004, a number of
seminal observations regarding skin barrier and immune dysregulation in AD have
been made with important therapeutic implications. A key addition to the
treatment algorithm based on our understanding that normal-appearing skin in
patients with AD is not normal is proactive therapy. Studies with both topical
steroids and a topical calcineurin inhibitor have shown that in patients with
relapsing AD, if they are able to clear or almost clear their eczema, then
twice-weekly proactive treatment of normal-appearing skin that tends to flare
leads to better disease control. For difficult-to-manage patients, the value of
wet wrap therapy is reaffirmed in the practice parameter update. In addition,
allergen immunotherapy is now a consideration in select patients with AD and
aeroallergen sensitivity. Beyond the practice parameter, novel approaches to
filaggrin deficiency are being evaluated. With respect to immune dysregulation,
dupilumab, a fully human monoclonal antibody directed at the IL-4 receptor alpha
subunit was recently shown to be effective in treating adults with
moderate-to-severe AD. Currently the only approved drug available for the systemic therapy of atopic
dermatitis is cyclosporine; however, based on current data from published
studies, azathioprine, methotrexate, and mycophenolate mofetil or mycophenolic
acid can be administered off-label. Some biologics on the market that have been
approved for other indications (ustekinumab, rituximab, tocilizumab) have been
successfully used in a few patients with atopic dermatitis. The world's first
prospective controlled studies with the biologic human anti-IL4R antibody
dupilumab for the indication "atopic dermatitis" were published in 2014. These
motivated (1) to extend the studies to dupilumab and (2) to clinically test
antagonization of other target molecules of TH2 polarized, atopic inflammation,
e.g., IL-13, IL-31, IL-22, TSLP, and CRTH2. A number of clinical trials are
currently recruiting in this area and will provide interesting new insights for
future therapeutic approaches in atopic dermatitis. |
Which human genes are more commonly related to craniosynostosis? | The genes that are most commonly linked to craniosynostoses are the members of the Fibroblast Growth Factor Receptor family FGFR3 and to a lesser extent FGFR1 and FGFR2. Some variants of the disease have been associated with the triplication of the MSX2 gene and mutations in NELL-1. NELL-1 is being regulated bu RUNX2, which has also been associated to cases of craniosynostosis. Other genes reported to have a role in the development of the disease are RECQL4, TWIST, SOX6 and GNAS. | Recently, a unique Pro250Arg point mutation in fibroblast growth factor receptor
3 (FGFR3) was reported in 61 individuals with coronal craniosynostosis from 20
unrelated families [Muenke et al. (1997): Am J Hum Genet 60:555-564]. The
discovery of this apparently common mutation has resulted in the definition of a
recognizable syndrome, through analysis of subtle clinical findings in families
who were previously thought to have a variety of other craniosynostosis
syndromes. Previous diagnoses in some of these families have included
Jackson-Weiss, Saethre-Chotzen, and Pfeiffer syndromes, as well as Adelaide-type
craniosynostosis and brachydactyly-craniosynostosis syndrome [Adès et al.
(1994): Am J Med Genet 51:121-130; von Gernet et al. (1996): Am J Med Genet
63:177-184; Reardon et al. (1997): J Med Genet 34:632-636; Bellus et al. (1996):
Nat Genet 14:174-176; Hollaway et al. (1995): Hum Mol Genet 4:681-683; Glass et
al. (1994): Clin Dysmorphol 3:215-223]. There appears to be a need to further
delineate the phenotype associated with this common mutation in FGFR3. We
compare the clinical characteristics of previously reported cases of this unique
Pro250Arg mutation with those of two additional families and suggest that this
syndrome with a unique mutational basis be designated coronal craniosynostosis
with brachydactyly and carpal/tarsal coalition due to Pro250Arg mutation in
FGFR3 gene, to emphasize the distinctive findings which may be present even in
the absence of coronal craniosynostosis. Throughout its complex morphogenesis, the vertebrate skull must at once protect
the brain and expand to accommodate its growth. A key structural adaptation that
allows this dual role is the separation of the bony plates of the skull with
sutures, fibrous joints that serve as growth centers and allow the calvarial
bones to expand as the brain enlarges. Craniosynostosis, the premature fusion of
one or more calvarial bones with consequent abnormalities in skull shape, is a
common developmental anomaly that disrupts this process. We found previously
that a single amino acid substitution in the homeodomain of the human MSX2 gene
is associated with the autosomal domit disorder craniosynostosis, Boston
type. This mutation enhances the affinity of Msx2 for its target sequence,
suggesting that the mutation acts by a domit positive mechanism. Consistent
with this prediction, we showed that general overexpression of Msx2 under the
control of the broadly expressed CMV promoter causes the calvarial bones to
invade the sagittal suture. Here we use tissue-specific overexpression of Msx2
within the calvarial sutures to address the developmental mechanisms of
craniosynostosis and skull morphogenesis. We demonstrate that a segment of the
Msx2 promoter directs reporter gene expression to subsets of cells within the
sutures. In late embryonic and neonatal stages, this promoter is expressed in
undifferentiated mesenchymal cells medial to the growing bone. By P4, promoter
activity is reduced in the suture, exhibiting a punctate pattern in
undifferentiated osteoblastic cells in the outer margin of the osteogenic front.
Overexpression of Msx2 under the control of this promoter is sufficient to
enhance parietal bone growth into the sagittal suture by P6. This phenotype is
preceded by an increase in both the number and the BrdU labeling of osteoblastic
cells in the osteogenic fronts of the calvarial bones. These findings suggest
that an important early event in MSX2-mediated craniosynostosis in humans is a
transient retardation of osteogenic cell differentiation in the suture and a
consequent increase in the pool of osteogenic cells. A unique Pro250Arg mutation in fibroblast growth factor receptor 3 (FGFR3) was
recently found in patients with non-syndromic craniosynostosis. We studied 18
Taiwan Chinese patients with various types of craniosynostosis to evaluate if
this mutation is also prevalent in the Chinese population. Genomic DNA was
analysed by polymerase chain reaction based restriction analysis and direct
sequencing to identify the Pro250Arg mutation in FGFR3. Five (28%) of 18
probands were heterozygous for the Pro250Arg mutation. Only those patients with
coronal synostosis carried this mutation.
CONCLUSION: Our findings suggest that all patients with coronal synostosis
should be examined for this unique mutation. Mutations in the fibroblast growth factor receptor 1, 2 and 3 (FGFR1, -2 and -3)
and TWIST genes have been identified in several syndromic forms of
craniosynostosis. There remains, however, a significant number of patients with
non-syndromic craniosynostosis in whom no genetic cause can be identified. We
describe a novel heterozygous mutation of FGFR2 (943G --> T, encoding the amino
acid substitution Ala315Ser) in a girl with non-syndromic unicoronal
craniosynostosis. The mutation is also present in her mother and her maternal
grandfather who have mild facial asymmetry but do not have craniosynostosis.
None of these individuals has the Crouzonoid appearance typically associated
with FGFR2 mutations. However, the obstetric history revealed that the proband
was in persistent breech presentation in utero and was delivered by Caesarean
section, at which time compression of the skull was apparent. We propose that
this particular FGFR2 mutation only confers a predisposition to craniosynostosis
and that an additional environmental insult (in this case foetal head constraint
associated with breech position) is necessary for craniosynostosis to occur. To
our knowledge, this is the first report of an interaction between a weakly
pathogenic mutation and intrauterine constraint, leading to craniosynostosis. Recently, the substitution of proline 250 by arginine in the fibroblast growth
factor receptor 3 (FGFR3) gene, has been identified in patients with
craniosynostosis and defines a new syndrome on a molecular basis. We report a
1-year-1-month-old female with bilateral coronal craniosynostosis who had the
P250R mutation in FGFR3 gene detected by DNA sequencing. She had brachycephaly,
temporal bossing, high and flat forehead, hypertelorism, mild proptosis, low set
ears and no digital abnormalities. She underwent surgical repair at 7 months and
her cosmetic problems were improved. Her development was normal up to 13 months
of age. DNA analysis from her parents showed that her father had the same
mutation. The phenotypes of the P250R mutation in the FGFR3 syndrome are
variable even within the same family, but main characteristic clinical features
are follows, 1) lateral or bilateral coronal craniosynostosis, 2) mild hand and
foot anomalies, and 3) sensory deafness. In FGFR3 syndrome the diagnosis of
P250R mutation by polymerase chain reaction (PCR) is very easy and important for
early diagnosis and genetic counseling. Apert (Ap) syndrome is characterized by premature cranial suture ossification
caused by fibroblast growth factor receptor 2 (FGFR-2) mutations. We studied the
role of cadherins and signaling events in the phenotypic alterations induced by
the Ap FGFR-2 S252W mutation in mutant immortalized fetal human calvaria
osteoblasts. The FGFR-2 mutation caused increased expression of the osteoblast
markers alkaline phosphatase (ALP), type 1 collagen (COLIA1), and osteocalcin
(OC) in long-term culture. The mutation also increased cell-cell aggregation,
which was suppressed by specific neutralizing anti-N- and anti-E-cadherin
antibodies. Mutant osteoblasts showed increased N- and E-cadherin, but not
N-cell adhesion molecule (N-CAM) messenger RNA (mRNA) and protein levels. This
was confirmed in vivo by the abundant immunoreactive N- and E-cadherins in
preosteoblasts in the Ap suture whereas N-CAM and alpha- and beta-catenins were
unaffected. Neutralizing anti-N-cadherin antibody or N-cadherin antisense (AS)
oligonucleotides but not anti-E-cadherin antibody or AS reduced ALP activity as
well as ALP, COLIA1, and OC mRNA overexpression in mutant osteoblasts. Analysis
of signal transduction revealed increased phospholipase Cgamma (PLCgamma) and
protein kinase Calpha (PKCalpha) phosphorylation and increased PKC activity in
mutant cells in basal conditions. Inhibition of PKC by calphostin C or the
PKCalpha-specific inhibitor Gö6976 suppressed the increased N-cadherin mRNA and
protein levels as well as the overexpression of ALP, COLIA1, and OC mRNA in
mutant cells. Thus, N-cadherin plays a role in the activation of osteoblast
differentiation marker genes in mutant osteoblasts and PKCalpha signaling
appears to be involved in the increased N-cadherin and osteoblast gene
expression induced by the S252W FGFR-2 mutation in human osteoblasts. Familial craniosynostosis due to Pro250Arg mutation in the fibroblast growth
factor receptor 3 gene. Most mutations in Crouzon, Pfeiffer, and Apert syndromes are in the
extracellular, third immunoglobulin-like domain and adjacent linker regions
(exons IIIa and IIIc) of the fibroblast growth factor receptor 2 (FGFR2) gene.
Using the published primers for PCR, a patient with Crouzon syndrome was found
to be homozygous for a mutation that results in a Q289P amino acid substitution
in FGFR2. Two additional patients; one with Apert syndrome and P253R mutation,
the other with Pfeiffer syndrome and S267P mutation, also appeared to be
homozygous. Using a new primer located 146 bp 5' of exon IIIa for PCR followed
by sequencing revealed an A to G polymorphism at -62 [corrected] position of
exon IIIa. All three patients were heterozygous for both the mutation and the
polymorphism. These results indicate that the polymorphism and the mutation are
not on the same chromosome. The single nucleotide polymorphism is located at the
second to the last base of the 3' end of the published primer. This primer
mismatch caused the failure of amplification of the normal chromosome and thus,
the apparent homozygosity. The frequency of this novel polymorphism was
determined to be 0.03 by studying 326 chromosomes from the general population.
We propose that a new primer should be used for mutational analysis of exon IIIa
of FGFR2 to avoid misdiagnosis caused by primer mismatch. A unique Pro250Arg point mutation in fibroblast growth factor receptor 3 (FGFR3)
was initially reported by Bellus et al. [1996: Nat Genet 14:174-176] and the
phenotype subsequently by Muenke et al. [1997: Am J Hum Genet 60:555-564],
Reardon et al. [1997: J Med Genet 34:632-636], and Graham et al. [1998: Am J Med
Genet 77:322-329]. These authors emphasized the pleiotropic nature of this form
of coronal craniosynostosis, including brachydactyly with carpal and/or tarsal
coalitions, with other anomalies at lower frequency. We report on a family with
autosomal domit coronal synostosis, segmentation and fusion anomalies of the
vertebra and ribs, and Sprengel shoulder due to the Pro250Arg mutation. We also
report a single case with an identical phenotype without the mutation. One of the genes involved in craniosynostosis syndromes is the fibroblast growth
factor receptor 2 (FGFR2) gene, a tyrosine kinase receptor gene. Upon ligand
binding the FGFR2 receptors dimerise, and this is followed by activation of the
intracellular tyrosine kinase domains. This initiates a cascade of signals that
influence cell division and differentiation. FGFR2 mutations have been found in
the Apert, Crouzon and Pfeiffer craniosynostosis syndromes. Most mutations are
gain of function mutations, inducing ligand-independent receptor activation or
altered ligand binding. With the exception of Apert syndrome, there is no clear
genotype-phenotype correlation. Many different mutations have been found in
Pfeiffer and Crouzon syndrome, but all of the mutations occur in the same
extracellular region of the receptor. Identical mutations have been found in
Pfeiffer and Crouzon syndrome. So within one family, both Crouzon and Pfeiffer
syndrome may occur. Mutations in other FGFR-genes have also been found in
craniosynostosis syndromes. Craniosynostosis caused by genetic factors includes a heterogeneous group of
over 100 syndromes, most with autosomal domit inheritance. Mutations in five
genes (FGFR1-, -2, -3, TWIST, and MSX2) causing craniosynostosis as the main
clinical feature were described. In most of these conditions, there are also
limb malformations. We report a two-generation kindred segregating microcornea,
optic nerve alterations and cataract since childhood, craniosynostosis, and
distal limb alterations, with a great clinical intrafamilial variability. The
ophthalmological problems here described seem to be unique to this genealogy
while similar feet alterations were apparently only described in two other
affected siblings with acro-cranial-facial dysostosis syndrome (ADS). However,
ADS has an autosomal recessive inheritance instead of the domit pattern of
the present genealogy. The candidate exons of the five genes previously
mentioned were tested through sequencing analysis presenting normal results in
all cases. Therefore, clinical and laboratory analyses in our patients suggest
that their phenotype represents a new syndrome very likely caused by mutation in
a gene different from those studied. Craniosynostosis is a congenital developmental disorder involving premature
fusion of cranial sutures, which results in an abnormal shape of the skull.
Significant progress in understanding the molecular basis of this phenotype has
been made for a small number of syndromic craniosynostosis forms. Nevertheless,
in the majority of the approximately 100 craniosynostosis syndromes and in
non-syndromic craniosynostosis the underlying gene defects and pathomechanisms
are unknown. Here we report on a male infant presenting at birth with
brachycephaly, proptosis, midfacial hypoplasia, and low set ears. Three
dimensional cranial computer tomography showed fusion of the lambdoid sutures
and distal part of the sagittal suture with a gaping anterior fontanelle.
Mutations in the genes for FGFR2 and FGFR3 were excluded. Standard chromosome
analysis revealed a de novo balanced translocation t(9;11)(q33;p15). The
breakpoint on chromosome 11p15 disrupts the SOX6 gene, known to be involved in
skeletal growth and differentiation processes. SOX6 mutation screening of
another 104 craniosynostosis patients revealed one missense mutation leading to
the exchange of a highly conserved amino acid (p.D68N) in a single patient and
his reportedly healthy mother. The breakpoint on chromosome 9 is located in a
region without any known or predicted genes but, interestingly, disrupts patches
of evolutionarily highly conserved non-genic sequences and may thus led to
dysregulation of flanking genes on chromosome 9 or 11 involved in skull vault
development. The present case is one of the very rare reports of an apparently
balanced translocation in a patient with syndromic craniosynostosis, and reveals
novel candidate genes for craniosynostoses and cranial suture formation. We studied the transcriptional regulation of NELL-1, a craniosynostosis-related
gene. We identitifed three OSE2 elements in the NELL-1 promoter that are
directly bound and transactivated by Runx2. Forced expression of Runx2 induces
NELL-1 expression in rat calvarial cells.
INTRODUCTION: We previously reported the upregulation of NELL-1 in human
craniosynostosis and the overexpression of Nell-1 in transgenic animals that
induced premature suture closure associated with increased osteoblast
differentiation. To study the transcriptional regulation of NELL-1, we analyzed
the 5' flanking region of the human NELL-1 gene. We identified three osteoblast
specific binding elements 2 (OSE2) sites (A, B, and C) within 2.2 kb upstream of
the transcription start site and further studied the functionality of these
sites.
MATERIALS AND METHODS: An area of 2.2 kb and a truncated 325 bp, which lacked
the three OSE sites, were cloned into a luciferase reporter gene, and
co-transfected with Runx2 expression plasmid. The three OSE2 sites were
individually mutated and co-transfected with Runx2 expression plasmid into Saos2
cells. Gel shifts and supershifts with Runx2 antibodies were used to determine
specific binding to OSE2 sites. CHIP assays were used to study in vivo binding
of Runx2 to the Nell-1 promoter. Runx2 expression plasmid was transfected into
wildtype and Runx2(-/-) calvarial cells. Nell-1, osteocalcin, and Runx2
expression levels were measured using RT-PCR.
RESULTS: Addition of Runx2 dose-dependently increased the luciferase activity in
the human NELL-1 promoter-luciferase p2213. The p325 truncated NELL-1 construct
showed significantly lower basal level of activity. Nuclear extract from Saos2
cells formed complexes with site A, B, and C probes and were supershifted with
Runx2 antibody. Mutation of sites A, B, and C significantly decreased basal
promoter activity. Furthermore, mutation of sites B and C had a blunted response
to Runx2, whereas mutation of site A had a lesser effect. Runx2 bound to NELL-1
promoter in vivo. Transfection of Runx2 in rat osteoblasts upregulated Nell-1
and Ocn expression, and in Runx2 null calvarial cells, both Nell-1 and Ocn
expression were rescued.
CONCLUSIONS: Runx2 directly binds to the OSE2 elements and transactivates the
human NELL-1 promoter. These results suggest that Nell-1 is likely a downstream
target of Runx2. These findings may also extend our understanding of the
molecular mechanisms governing the pathogenesis of craniosynostosis. Craniosynostosis is a common birth defect ( approximately 1/3,000 births)
resulting from chromosome imbalances, gene mutations or unknown causes. We
report a 6-month-old female with multiple sutural synostosis and prenatal onset
growth deficiency, developmental delay, facial dysmorphism, congenital heart
defect, and inguinal hernia. An integrated approach of standard cytogenetics,
mBAND, locus-specific FISH, and 75 kb resolution array-CGH disclosed a complex
chromosome 5 rearrangement, resulting in 3 paracentric inversions, 2 between-arm
insertions, and partial duplication of 5q35. An extra copy of the MSX2 gene,
which maps within the duplicated segment and is mutated in Boston-type
craniosynostosis, was confirmed by molecular cytogenetic studies. Our study
confirms that early fusion of cranial sutures commonly observed in the dup(5q)
syndrome is caused by triplication of the MSX2 gene and strongly supports the
crucial role of this gene in the development of craniofacial structures. We report on a 6-month-old boy with craniosynostosis, pseudohypoparathyroidism
type 1a (PHP1A), and a GNAS gene mutation. He had synostoses of the coronal,
frontal, and sagittal sutures, brachyturricephaly, and hydrocephaly. He also had
congenital hypothyroidism, round face, full cheeks, shortness of limbs, mild
developmental delay, and muscular hypotonia. Because of progressive
hydrocephaly, the synostosis was corrected surgically but circulatory
decompensation led to disseminated intravascular coagulation and cerebral
infarctions. Our patient died 8 days later. Postmortem molecular studies of
GNAS, the gene for guanine nucleotide-binding protein, alpha-stimulating
activity polypeptide (gene for PHP1A), identified a de novo heterozygous 3 bp in
frame deletion predicting a deletion of the asparagine residue at position 377
(deltaN377). This is the second report of this mutation. Results of molecular
studies of craniosynostosis genes (FGFR2, FGFR3) and of numerous genetic
variants predisposing to bleeding disorders were normal. We question whether
craniosynostosis and trauma-induced bleeding disorder may be manifestations of
PHP1A, or if our patient had two or three different congenital disorders. OBJECTIVES: We describe the first cohort-based analysis of the impact of genetic
disorders in craniosynostosis. We aimed to refine the understanding of prognoses
and pathogenesis and to provide rational criteria for clinical genetic testing.
METHODS: We undertook targeted molecular genetic and cytogenetic testing for 326
children who required surgery because of craniosynostosis, were born in
1993-2002, presented to a single craniofacial unit, and were monitored until the
end of 2007.
RESULTS: Eighty-four children (and 64 relatives) had pathologic genetic
alterations (86% single-gene mutations and 14% chromosomal abnormalities). The
FGFR3 P250R mutation was the single largest contributor (24%) to the genetic
group. Genetic diagnoses accounted for 21% of all craniosynostosis cases and
were associated with increased rates of many complications. Children with an
initial clinical diagnosis of nonsyndromic craniosynostosis were more likely to
have a causative mutation if the synostoses were unicoronal or bicoronal (10 of
48 cases) than if they were sagittal or metopic (0 of 55 cases; P = .0003).
Repeat craniofacial surgery was required for 58% of children with single-gene
mutations but only 17% of those with chromosomal abnormalities (P = .01).
CONCLUSIONS: Clinical genetic assessment is critical for the treatment of
children with craniosynostosis. Genetic testing of nonsyndromic cases (at least
for FGFR3 P250R and FGFR2 exons IIIa/c) should be targeted to patients with
coronal or multisuture synostoses. Single-gene disorders that disrupt
physiologic signaling in the cranial sutures often require reoperation, whereas
chromosomal abnormalities follow a more-indolent course, which suggests a
different, secondary origin of the associated craniosynostosis. |
Are transcribed ultraconserved regions involved in cancer? | Yes, it appears that there is widespread T-UCR (Transcribed - UltraConserved Region) involvement in diverse cellular processes that are deregulated in the process of tumourigenesis. Transcribed ultraconserved regions (T-UCRs) are a subset of 481 sequences longer than 200 bp, which are absolutely conserved between orthologous regions of human, rat and mouse genomes, and are actively transcribed. It has recently been proven in cancer systems that differentially expressed T-UCRs could alter the functional characteristics of malignant cells. | Different classes of non-coding RNAs, including microRNAs, have recently been
implicated in the process of tumourigenesis. In this study, we examined the
expression and putative functions of a novel class of non-coding RNAs known as
transcribed ultraconserved regions (T-UCRs) in neuroblastoma. Genome-wide
expression profiling revealed correlations between specific T-UCR expression
levels and important clinicogenetic parameters such as MYCN amplification
status. A functional genomics approach based on the integration of multi-level
transcriptome data was adapted to gain insights into T-UCR functions.
Assignments of T-UCRs to cellular processes such as TP53 response,
differentiation and proliferation were verified using various cellular model
systems. For the first time, our results define a T-UCR expression landscape in
neuroblastoma and suggest widespread T-UCR involvement in diverse cellular
processes that are deregulated in the process of tumourigenesis. During recent years, novel approaches and new technologies have revealed a
startling level of complexity of higher eukaryotes' transcriptome. A large
proportion of the transcriptional output is represented by protein noncoding
RNAs (ncRNAs) that arise from the "dark matter" of the genome. Focus on such
sequences has revealed numerous RNA subtypes with several functions in RNA
processing and gene expression regulation, and deep sequencing studies imply
that many remain to be discovered. This review gives a picture of the state of
the art of a novel class of long ncRNA known as transcribed-ultraconserved
regions (T-UCRs). Most recent studies show that they are significantly altered
in adult chronic lymphocytic leukemias, carcinomas, and pediatric
neuroblastomas, leading to the hypothesis that UCRs may play a role in
tumorigenesis and promising innovative future T-UCR-based therapeutic
approaches. OBJECTIVES: The development of colorectal cancer (CRC) is characterized by
multiple genetic alterations. Transcribed ultraconserved regions (T-UCRs) are a
subset of 481 sequences longer than 200 bp, which are absolutely conserved
between orthologous regions of human, rat and mouse genomes, and are actively
transcribed. It has recently been proven in cancer systems that differentially
expressed T-UCRs could alter the functional characteristics of maligt cells.
Genome-wide profiling revealed that T-UCRs have distinct signatures in human
leukemia and carcinoma.
METHODS: In our study, we examined the expression levels of uc.43, uc.73,
uc.134, uc.230, uc.339, uc.388 and uc.399 in 54 samples of primary colorectal
carcinomas and 15 samples of non-tumoral adjacent tissues by real-time PCR.
T-UCR expression levels were also correlated with commonly used
clinicopathological features of CRC.
RESULTS: Expression levels of uc.73 (p = 0.0139) and uc.388 (p = 0.0325) were
significantly decreased in CRC tissue, and uc.73 indicated a positive
correlation with overall survival (p = 0.0315). The lower expression of uc.388
was associated with the distal location of CRC (p = 0.0183), but no correlation
of any evaluated T-UCR with clinical stage, grade and tumor diameter was
observed.
CONCLUSION: Our preliminary results suggest that uc.73 and uc.388 could be
potential diagnostic and prognostic biomarkers in CRC patients. Much effort in cancer research has focused on the tiny part of our genome that
codes for mRNA. However, it has recently been recognized that microRNAs also
contribute decisively to tumorigenesis. Studies have also shown that epigenetic
silencing by CpG island hypermethylation of microRNAs with tumor suppressor
activities is a common feature of human cancer. The importance of other classes
of non-coding RNAs, such as long intergenic ncRNAs (lincRNAs) and transcribed
ultraconserved regions (T-UCRs) as altered elements in neoplasia, is also
gaining recognition. Thus, we wondered whether there were other ncRNAs
undergoing CpG island hypermethylation-associated inactivation in cancer cells.
We focused on the small nucleolar RNAs (snoRNAs), a subset of ncRNA with a wide
variety of cellular functions, such as chemical modification of RNA, pre-RNA
processing and control of alternative splicing. By data mining snoRNA databases
and the scientific literature, we selected 49 snoRNAs that had a CpG island
within ≤ 2 Kb or that were processed from a host gene with a 5'-CpG island.
Bisulfite genomic sequencing of multiple clones in normal colon mucosa and the
colorectal cancer cell line HCT-116 showed that 46 snoRNAs were equally
methylated in the two samples: completely unmethylated (n = 26) or fully
methylated (n = 20). Most interestingly, the host gene-associated 5'-CpG islands
of the snoRNAs SNORD123, U70C and ACA59B were hypermethylated in the cancer
cells but not in the corresponding normal tissue. CpG island hypermethylation
was associated with the transcriptional silencing of the respective snoRNAs.
Results of a DNA methylation microarray platform in a comprehensive collection
of normal tissues, cancer cell lines and primary maligcies demonstrated that
the observed hypermethylation of snoRNAs was a common feature of various tumor
types, particularly in leukemias. Overall, our findings indicate the existence
of a new subclass of ncRNAs, snoRNAs, that are targeted by epigenetic
inactivation in human cancer. Recent data have linked hypoxia, a classic feature of the tumor
microenvironment, to the function of specific microRNAs (miRNAs); however,
whether hypoxia affects other types of noncoding transcripts is currently
unknown. Starting from a genome-wide expression profiling, we demonstrate for
the first time a functional link between oxygen deprivation and the modulation
of long noncoding transcripts from ultraconserved regions, termed
transcribed-ultraconserved regions (T-UCRs). Interestingly, several
hypoxia-upregulated T-UCRs, henceforth named 'hypoxia-induced noncoding
ultraconserved transcripts' (HINCUTs), are also overexpressed in clinical
samples from colon cancer patients. We show that these T-UCRs are predomitly
nuclear and that the hypoxia-inducible factor (HIF) is at least partly
responsible for the induction of several members of this group. One specific
HINCUT, uc.475 (or HINCUT-1) is part of a retained intron of the host
protein-coding gene, O-linked N-acetylglucosamine transferase, which is
overexpressed in epithelial cancer types. Consistent with the hypothesis that
T-UCRs have important function in tumor formation, HINCUT-1 supports cell
proliferation specifically under hypoxic conditions and may be critical for
optimal O-GlcNAcylation of proteins when oxygen tension is limiting. Our data
gives a first glimpse of a novel functional hypoxic network comprising
protein-coding transcripts and noncoding RNAs (ncRNAs) from the T-UCRs category. |
In which breast cancer patients can palbociclib be used? | Palbociclib is useful for women with hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer. | Women with hormone receptor-positive, human epidermal growth factor receptor 2-
negative breast cancer-the most common subtype-have new options as palbociclib
and similar drugs debut. This article outlines the rationale and evidence for
their use. |
Do patients with Pendred syndrome present congenital deafness? | Congenital deafness is one of the characteristics of Pendred syndrome patients. | Although 5% of all cases of congenital deafness are caused by Pendred's
syndrome, there are few reports in the literature. Seven patients with Pendred's
syndrome in three families living in the same village were detected. For that
reason, the syndrome is reviewed in light of the literature. The sex
distribution of the patients with Pendred's syndrome and their families was
recorded. We tested for thyroxine, triiodothyronine, thyroid-stimulating
hormone, triiodothyronine resin uptake, and perchlorate, and performed caloric
testing. In one patient, subtotal thyroidectomy was performed. In the
histopathologic study, a thyroid nodule filled with colloid was found.
Chromosome studies showed no anomalies in any patient. Five of the patients were
deaf-mutes. We observed that the parents were cousins in all three families.
These families also had healthy children, and the existence of the syndrome in
both sexes points to an autosomal recessive trait. OBJECTIVE: Pendred's syndrome is an association between congenital neurosensory
deafness and goitre with abnormal discharge of iodide following perchlorate
challenge, indicating a defect of iodide organification. Although Pendred's
syndrome may cause up to 7.5% of all cases of congenital deafness, the molecular
basis of the association between the hearing loss and the thyroid organification
defect remains unknown. We chose to investigate the role of the thyroid
peroxidase (TPO) gene as the genetic defect in Pendred's syndrome.
DESIGN: A highly informative variable number tandem repeat (VNTR), located 1.5
kb downstream of exon 10 of the TPO gene, was used to search for genetic linkage
in multiple sibships affected by Pendred's syndrome.
PATIENTS: Seven kindreds were recruited from the UK, each with at least two
affected members. We have also examined a large inbred Israeli family with two
affected offspring and five unaffected children.
MEASUREMENTS: Individuals were assigned affected status based on the
characteristic clinical features of Pendred's syndrome, namely the presence of
congenital sensorineural hearing loss and the appearance in early life of a
goitre. Additionally, at least one affected member from each sibship had a
characteristic positive perchlorate discharge test (Morgans & Trotter, 1958).
PCR amplification of genomic DNA at the TPO VNTR allowed assignment of genotypes
to each individual and the calculation of a two-point LOD score.
RESULTS: In six of the nine sibships analysed we found obligatory recombination
between TPO and Pendred's syndrome. Non-complementation observed in affected
parents with an affected offspring excluded TPO in an affected sibship with
genotype sharing and supports a hypothesis of genetic homogeneity for Pendred's
syndrome. In two sibships, mutation of the TPO gene as the cause of Pendred's
syndrome could not be excluded.
CONCLUSIONS: These data suggest that defects at the thyroid peroxidase locus on
chromosome 2 are not the major cause of Pendred's syndrome. Pendred's syndrome is manifested by congenital sensorineural deafness in
association with familial goiter due to defective organic binding of iodine in
the thyroid gland. The majority of patients with Pendred's syndrome are
euthyroid. We report on an unusual case of a patient with Pendred's syndrome
presenting with amenorrhea and late-onset hypothyroidism. Pendred syndrome is an autosomal recessive disorder characterized by goiter and
congenital deafness. The primary defect is not yet known, although the gene
causing Pendred syndrome has been localized very recently on chromosome 7q, a
region that also contains a gene responsible for nonsyndromal hearing loss
(DFNB4). We confirmed linkage to this chromosome 7 region in five Pendred
families originating from different ethnic groups, with a highest cumulative lod
score of 8.26 for marker D7S501. In combination with previous reports, our
results define a candidate region for the Pendred gene of 1.7 cM flanked by
markers D7S501 and D7S692. Pendred syndrome comprises the association of severe congenital sensorineural
deafness with thyroid pathology. Although it is the commonest form of syndromic
hearing loss, the primary genetic defect remains unknown. The variable clinical
presentation allied to the difficulty in securing the diagnosis have resulted in
relatively poor documentation of the radiological features of this syndrome. We
now present data on 40 patients, all complying with strict diagnostic criteria
for the disorder, and describe our experience of the prevalence of specific
malformations of the inner ear as well as comparing the relative merits of
computed tomography (CT) and magnetic resoce imaging (MRI) in the
investigation of this inherited condition. Deficiency of the interscalar septum
in the distal coils of the cochlea (Mondini deformity) was found to be a common
but probably not a constant feature of Pendred syndrome. However, enlargement of
the endolymphatic sac and duct in association with a large vestibular aqueduct
was present in all 20 patients examined by MRI. We conclude that thin section
high resolution MRI on a T2 protocol in the axial and sagittal planes is the
imaging investigation of choice. Pendred's syndrome is an autosomal recessive disease characterized by goiter,
impaired iodide organification, and congenital sensorineural deafness. The gene
mutated in Pendred's syndrome, PDS (Pendred's syndrome gene), was cloned very
recently and encodes the putative sulfate transporter pendrin. Pendred's
syndrome may account for up to 10% of the cases with hereditary hearing loss,
and pendrin mutations have also been found in a kindred with non-syndromic
deafness. In this study, 41 individuals from a large, highly inbred pedigree
from Northeastern Brazil were examined for features of Pendred's syndrome.
Linkage studies and sequence analysis of the coding region of the PDS gene were
performed with DNA from 36 individuals. The index patient, with the classical
triad of deafness, positive perchlorate test, and goiter, was found to be
homozygous for a deletion of thymidine 279 in exon 3, resulting in a frameshift
and a premature stop codon at amino acid 96. This alteration resulted in
truncation of the protein in the first transmembrane domain. Two other patients
with deafness were found to be homozygous for this mutation; 19 were
heterozygous and 14 were homozygous for the wild type allele. Surprisingly, 6
deaf individuals in this kindred were not homozygous for the PDS gene mutation;
3 were heterozygous and 3 were homozygous for the wild type allele, suggesting a
probable distinct genetic cause for their deafness. All 3 homozygous individuals
for the PDS mutation had goiters. However, goiters were also found in 10
heterozygous individuals and in 6 individuals without the PDS mutation and are
most likely caused by iodine deficiency. In conclusion, we identified a novel
mutation in the PDS gene causing Pendred's syndrome. The comparison of phenotype
and genotype reveals, however, that phenocopies generated by distinct
environmental and/or genetic causes are present in this kindred and that the
diagnosis of Pendred's syndrome may be difficult without molecular analysis. Pendred's syndrome is an autosomal recessive disease characterized by goiter and
congenital sensorineural deafness. Most patients with Pendred's syndrome are
euthyroid, but the perchlorate test is positive indicating an impaired iodide
organification. The sensorineural deafness is typically associated with a
malformation of the inner ear, referred to as Mondini cochlea. The incidence of
Pendred's syndrome is thought to be as high as 7.5 to 10 in 100,000 individuals,
and it has been estimated to account for about 10% of the cases with hereditary
deafness. Linkage of Pendred's syndrome to chromosome 7q22-31.1 was first
established in 1996, and the Pendred's syndrome gene (PDS gene) was cloned in
1997. The PDS gene encodes pendrin, a highly hydrophobic 780 aminoacid protein
with 11 transmembrane domains. Its function is unknown. Sequence comparison
reveals a very high homology to several sulfate transporters suggesting that it
could be a sulfate or anion transporter. A wide spectrum of mutations in the PDS
gene has now been associated with Pendred's syndrome. Molecular analysis of the
PDS gene is useful to make a definite diagnosis in familial and sporadic cases
with Pendred's syndrome, and will be helpful for determining the true prevalence
of this disorder. Pendred syndrome is the autosomal recessively transmitted association of
familial goiter and congenital deafness. There is no specific biochemical marker
of this disease, and the diagnosis depends upon the demonstration of the triad
of congenital sensorineural hearing loss, goiter, and abnormal perchlorate
discharge test. Pendred syndrome is caused by mutations within the putative ion
transporter gene (PDS gene), located on chromosome 7q. A wide variation in the
clinical presentation of this condition, and its well documented phenotypic
overlap with other thyroid disorders (such as Hashimoto's thyroiditis), can lead
to diagnostic difficulties. The potential for misdiagnosis increases when these
disorders occur coincidentally in the same family. We describe a kindred in
which Pendred syndrome, autoimmune thyroiditis, and simple goiter coexisted, to
highlight these diagnostic pitfalls and to illustrate the use of mutational
analysis in resolving diagnostic confusion. Pendred syndrome is an autosomal recessive disorder characterized by congenital
deafness and goiter. The gene responsible for this syndrome is located on
chromosome 7q31. The disorder is related to a defect in iodine organification,
but the molecular basis of the defect remains unknown. We report two cases of
Pendred syndrome, a young woman and her brother. The patients presented
deafness, goiter that appeared in the prepubertal years, and a positive
perchloriate discharge test. The genetic factors, clinical features, and
diagnosis are reviewed. Although the textbook view of Pendred syndrome is that of an autosomal recessive
condition characterized by deafness and goitre, it is increasingly clear that
not all such patients present this classical clinical picture. Malformations of
the inner ear, specifically enlargement of the vestibular aqueduct, are common
in Pendred syndrome and mutations in the PDS (Pendred Syndrome) gene have been
recorded in patients presenting with deafness and vestibular aqueduct dilatation
only, without other features of Pendred syndrome. Since this is the most common
radiological malformation of the cochlea in deaf patients, we investigated what
proportion of such cases were due to mutation of the PDS gene. We assessed 57
patients referred with radiological evidence of vestibular aqueduct enlargement,
by history, clinical examination, perchlorate discharge test and molecular
analysis of the PDS locus. Forty-one patients (72%) had unequivocal evidence of
Pendred syndrome. The finding of a single heterozygous mutation at the PDS gene
in a further eight was strongly suggestive of a critical role for pendrin, the
protein product of the PDS gene, in the generation of enlarged vestibular
aqueducts in at least 86% (49/57 cases) of patients with this radiological
malformation. Securing the diagnosis of Pendred syndrome may be difficult,
especially in the single case. Goitre is an inconstant finding, and the
perchlorate discharge test, although helpful, is of diagnostic value only if
abnormal. Enlargement of the vestibular aqueduct should be considered as the
most likely presentation of Pendred syndrome and should prompt specific
investigation of that diagnostic possibility. Pendred syndrome might henceforth
be recharacterized as deafness with enlargement of the vestibular aqueduct,
which is sometimes associated with goitre. In this article we describe detailed pathological and molecular genetics studies
in a consanguineous kindred with Pendred's syndrome. The index patient was a
53-year-old female patient with congenital deafness and goiter. Her parents were
first-degree cousins. She had a large goiter (150 g) that had been present since
childhood. One of her sisters and a niece are also deaf and have goiter as well.
The presence of Pendred's syndrome was confirmed by a positive perchlorate test
and the demonstration of a Mondini malformation. Thyroid function tests (under
levothyroxine [LT4] therapy) were in the euthyroid range with a thyrotropin
[TSH] level of 2.8 microU/mL (0.2-3.2), a serum total thyroxine (T4) of 90
nmol/L (54-142), and a serum total triiodothyronine (T3) of 2.7 nmol/L
(0.8-2.4). Total thyroidectomy was performed, and the mass in the right lobe was
found to have invaded adjacent tissues. The histopathological findings were
consistent with a follicular carcinoma with areas of anaplastic transformation
and lung metastasis. The patient was treated twice with 100 mCi 131iodine (3,700
MBq) and received suppressive doses of LT4. Postoperatively, the serum
thyroglobulin (Tg) levels remained markedly elevated (2,352 to 41,336 ng/mL).
The patient died of a sudden severe episode of hemoptysis. Sequence analysis of
the PDS gene performed with DNA from the two relatives with Pendred's syndrome
revealed the presence of a deletion of thymidine 279 in exon 3, a point mutation
that results in a frameshift and a premature stop codon at codon 96 in the
pendrin molecule. We concluded that prolonged TSH stimulation because of iodine
deficiency or dyshormonogenesis in combination with mutations of oncogenes
and/or tumor suppressor genes, may result in the development of follicular
thyroid carcinomas that undergo transformation into anaplastic cancers. It is
likely that these pathogenetic mechanisms have been involved in the development
of aggressive metastatic thyroid cancer in this unusual patient with Pendred's
syndrome. Deafness means partial or complete hearing impairment and is one of the most
prevalent sensory defects in humans. It can be due to genetic or environmental
causes or a combination of both and may be Syndromic (associated with additional
clinical features) or nonsyndromic (no other recognizable abnormal associated
phenotype). The overall impact of hearing impairment is greatly influenced by
the severity of hearing defect and by the age of onset. If defect is severe and
presents in early childhood, it has dramatic effect on speech acquisition and
thereby cognitive and psychosocial development. The mutations shown in the paper
results in the conformational changes of protein and influence the phenotype of
the affected individuals. For recessive cases of deafness it is possible to
reduce the incidence of deafness by carrier screening in the families with
multiple affected individuals and genetic counselling. Pendred Syndrome can be
characterized by the triad composed of familial goitre, abnormal perchlorate
discharge and congenital deafness. Pendred syndrome and non-syndromic recessive deafness associated with enlarged
vestibular aqueduct (NSRD with EVA) are caused by mutations in the SLC26A4 (PDS)
gene. Unlike NSRD with EVA, Pendred syndrome is characterized by goiter, which
may be present after early adulthood. However, the clinical diagnosis of these
two disorders is difficult in deaf children. Expression of the SLC26A4 gene may
be responsible for iodide transport in the thyroid as well as for formation and
function of the inner ear. Here, we analyzed the SLC26A4 gene and performed
thyroid function tests (FT3, FT4, TSH, and Thyroglobulin) on six congenitally
deaf infants (mean age 2.7 years) with EVA. Mutation of the SLC26A4 gene was
identified in five patients: four were compound heterozygous (H723R/919-2A>G,
H723R/IVS15+5G>A, H723R/R581S, IVS7-2A>G/IVS8+1G>A), the fifth had a frameshift
mutation (322delC). All the patients demonstrated an elevation of serum
thyroglobulin level. FT3 level was elevated in four of the five patients. The
patient who did not have a detectable gene mutation showed normal thyroid
function. We conclude that the mutations in the SLC26A4 gene identified here are
highly associated with high serum thyroglobulin levels in congenital and
deafness infants. These mutations may be of value for the diagnosis of Pendred
syndrome and NSRD with EVA. Pendred syndrome is an autosomal recessive disorder characterized by congenital
sensorineural deafness, goiter, and impaired iodide organification. It is caused
by mutations in the PDS gene. Most published mutation studies of Pendred
syndrome have dealt with Western populations. In this study, we examined
clinical and molecular characteristics of 16 affected individuals in 6 unrelated
Thai families. Of all the affected, 100% (16/16) had bilateral deafness, 68.8%
(11/16) goiters, and 25% (4/16) hypothyroidism. Follicular thyroid carcinoma and
Hürthle cell adenoma were found in affected members of a family, raising the
possibility of an increased risk of thyroid carcinoma in Pendred syndrome
patients. Sequence analysis of the entire coding region of the PDS gene
successfully identified all 12 mutant alleles in these 6 families. The 12
identified mutant alleles constituted 6 distinct mutations including 3 splice
site mutations (IVS4-1G>A, IVS7-2A>G, IVS9- 1G>A), one frame shift mutation
(1548insC) and 2 missense mutations (T67S, H723R). Eight mutations out of 12
were constituted by IVS7- 2A>G and 1548insC, each one being present in 4
distinct alleles in our studied group. The identification of these two frequent
PDS mutations will facilitate the molecular diagnosis of Pendred syndrome in
Thai populations. In addition, three newly identified mutations, T67S,
IVS4-1G>A, and IVS9-1G>A, were not observed in 50 unrelated healthy Thai
controls. CONTEXT: Goiter and deafness can be associated in some genetic syndromes, e.g.
Pendred syndrome (PS) and resistance to thyroid hormone (RTH). PS is an
autosomal recessive disorder characterized by goiter and sensorineural hearing
impairment with an enlarged vestibular aqueduct bilaterally. RTH is an autosomal
domit condition of reduced tissue sensitivity to thyroid hormone in which
goiter is very frequent and hearing loss occurs in about 20% of patients.
OBJECTIVE, PATIENTS, AND DESIGN: The objective of this study was to identify the
cause of goiter and deafness in two sisters born to healthy unrelated parents.
We present their history, clinical presentation, and follow-up and report the
results of molecular genetic investigations.
RESULTS: The elder sister had an elevated TSH level at newborn screening
followed by subclinical hypothyroidism, childhood-onset goiter, and bilateral
progressive sensorineural hearing impairment with enlarged vestibular aqueducts,
consistent with a diagnosis of PS. Her younger sister had congenital goiter,
elevated free T3 and free T4 concentrations with unsuppressed TSH, sinus
tachycardia, and bilateral progressive sensorineural hearing impairment with
enlarged vestibular aqueducts. This clinical presentation was consistent with a
diagnosis of RTH, in which, however, inner ear malformations are uncommon.
Interestingly, molecular genetic testing showed that, whereas the elder sister
is affected by PS, the younger sister has both PS (due to compound heterozygous
SLC26A4 mutations) and RTH (due to a novel de novo heterozygous THRB mutation).
CONCLUSIONS: This is the first report of the cooccurrence, in the same
individual, of PS and RTH, two genetic syndromes both associated with goiter and
hearing impairment. Pendred syndrome (PDS) is an autosomal recessive disorder characterized by
congenital deafness, goiter and iodide organification defect. Presence of inner
ear malformations is essential for the clinical diagnosis. Most individuals with
PDS are clinically and biochemically euthyroid. Mutations in the PDS gene
encoding pendrin protein have been shown to be associated with PDS. It has been
recently demonstrated that some families with features of PDS do not have the
inner ear malformations and mutations in the PDS gene. This condition has been
named as "pseudo-Pendred syndrome" (pseudo-PDS), and has been hypothesized to be
of autoimmune origin. Here we report four siblings who have goiter, severe
hypothyroidism, a positive perchlorate discharge test and sensorineural
deafness, but not the inner ear abnormality which is diagnostic for PDS. We
suggest that thyroid peroxidase (TPO) gene should be analyzed in pseudo-PDS
patients with congenital goitrous hypothyroidism and deafness. INTRODUCTION: Pendred syndrome, a combination of sensorineural deafness,
impaired organification of iodide in the thyroid and goitre, results from
biallelic defects in pendrin (encoded by SLC26A4), which transports chloride and
iodide in the inner ear and thyroid respectively. Recently, pendrin has also
been identified in the kidneys, where it is found in the apical plasma membrane
of non-α-type intercalated cells of the cortical collecting duct. Here, it
functions as a chloride-bicarbonate exchanger, capable of secreting bicarbonate
into the urine. Despite this function, patients with Pendred syndrome have not
been reported to develop any significant acid-base disturbances, except a single
previous reported case of metabolic alkalosis in the context of Pendred syndrome
in a child started on a diuretic.
CASE REPORT: We describe a 46-year-old female with sensorineural deafness and
hypothyroidism, who presented with severe hypokalaemic metabolic alkalosis
during inter-current illnesses on two occasions, and who was found to be
homozygous for a loss-of-function mutation (V138F) in SLC26A4. Her acid-base
status and electrolytes were unremarkable when she was well.
CONCLUSION: This case illustrates that, although pendrin is not usually required
to maintain acid-base homeostasis under ambient condition, loss of renal
bicarbonate excretion by pendrin during a metabolic alkalotic challenge may
contribute to life-threatening acid-base disturbances in patients with Pendred
syndrome. Pendred syndrome and DFNB4 (autosomal recessive nonsyndromic congenital
deafness, locus 4) are associated with autosomal recessive congenital
sensorineural hearing loss and mutations in the SLC26A4 gene. Extensive allelic
heterogeneity, however, necessitates analysis of all exons and splice sites to
identify mutations for individual patients. Although Sanger sequencing is the
gold standard for mutation detection, screening methods supplemented with
targeted sequencing can provide a cost-effective alternative. One such method,
denaturing high-performance liquid chromatography, was developed for clinical
mutation detection in SLC26A4. However, this method inherently cannot
distinguish homozygous changes from wild-type sequences. High-resolution melting
(HRM), on the other hand, can detect heterozygous and homozygous changes
cost-effectively, without any post-PCR modifications. We developed a closed-tube
HRM mutation detection method specific for SLC26A4 that can be used in the
clinical diagnostic setting. Twenty-eight primer pairs were designed to cover
all 21 SLC26A4 exons and splice junction sequences. Using the resulting
amplicons, initial HRM analysis detected all 45 variants previously identified
by sequencing. Subsequently, a 384-well plate format was designed for up to
three patient samples per run. Blinded HRM testing on these plates of patient
samples collected over 1 year in a clinical diagnostic laboratory accurately
detected all variants identified by sequencing. In conclusion, HRM with targeted
sequencing is a reliable, simple, and cost-effective method for SLC26A4 mutation
screening and detection. Thyroid hormones are essential for normal development and metabolism. Their
synthesis requires transport of iodide into thyroid follicles. The mechanisms
involving the apical efflux of iodide into the follicular lumen are poorly
elucidated. The discovery of mutations in the SLC26A4 gene in patients with
Pendred syndrome (congenital deafness, goiter, and defective iodide
organification) suggested a possible role for the encoded protein, pendrin, as
an apical iodide transporter. We determined whether TSH regulates pendrin
abundance at the plasma membrane and whether this influences iodide efflux.
Results of immunoblot and immunofluorescence experiments reveal that TSH and
forskolin rapidly increase pendrin abundance at the plasma membrane through the
protein kinase A pathway in PCCL-3 rat thyroid cells. The increase in pendrin
membrane abundance correlates with a decrease in intracellular iodide as
determined by measuring intracellular (125)iodide and can be inhibited by
specific blocking of pendrin. Elimination of the putative protein kinase A
phosphorylation site T717A results in a diminished translocation to the membrane
in response to forskolin. These results demonstrate that pendrin translocates to
the membrane in response to TSH and suggest that it may have a physiological
role in apical iodide transport and thyroid hormone synthesis. OBJECTIVES: Mutations in the SLC26A4 gene (7q22.3-7q31.1) are considered one of
the most common causes of genetic hearing loss. There are two clinical forms
related to these mutations: syndromic and non-syndromic deafness. The first one
is named Pendred Syndrome (PS) when deafness is associated with thyroid goiter;
the second is called DFNB4, when no other symptoms are present. Both are
transmitted as an autosomal recessive trait, but simple heterozygotes can
develop both forms of deafness. Actually it is thought that Pendred Syndrome
occurs when both alleles of SLC26A4 gene are mutated; DFNB4 seems due to
monoallelic mutations. PS and DFNB4 can be associated with inner ear
malformations. In most of the cases (around 80%), these consist in Enlarged
Vestibular Aqueduct (EVA). EVA can also be present without SLC26A4 mutations.
Understanding the role of new SLC26A4 variants should facilitate clinical
assessment, as well as diagnostic and therapeutic approaches. This investigation
aims to detect and report genetic causes of two unrelated Italian boys with
hearing loss.
METHODS: Patients and family members underwent clinical, audiological and
genetic evaluations. To identify genetic mutations, DNA sequencing of SLC26A4
gene (including all 21 exons, exon-intron boundaries and promoter region) was
carried out.
RESULTS: Both probands were affected by congenital, progressive and fluctuating
mixed hearing loss. Temporal bone imaging revealed a bilateral EVA with no other
abnormalities in both cases. Probands were heterozygotes for previously
undescribed mutations in the SLC26A4 gene: R409H/IVS2+1delG (proband 1) and
L236P/K590X (proband 2). No other mutations were detected in GJB2, GJB6 genes or
mitochondrial DNA (mit-DNA).
CONCLUSIONS: The IVS2+1delG and K590X mutations have not yet been described in
literature but there is some evidence to suggest that they have a pathological
role. The results underlined the importance of considering the complete DNA
sequencing of the SLC26A4 gene for differential molecular diagnosis of deafness,
especially in those patients affected by congenital, progressive and fluctuating
mixed hearing loss with bilateral EVA. |
List side effects of SGLT2 inhibitors? | SGLT2 inhibitors can be associated with urogenital infections related to the enhanced glycosuria, and low blood pressure. | BACKGROUND: The kidney plays an important role in glucose metabolism, and has
been considered a target for therapeutic intervention. The sodium-glucose
cotransporter type 2 (SGLT2) mediates most of the glucose reabsorption from the
proximal renal tubule. Inhibition of SGLT2 leads to glucosuria and provides a
unique mechanism to lower elevated blood glucose levels in diabetes. The purpose
of this review is to explore the physiology of SGLT2 and discuss several SGLT2
inhibitors which have clinical data in patients with type 2 diabetes.
METHODS: We performed a PubMed search using the terms "SGLT2" and "SGLT2
inhibitor" through April 10, 2012. Published articles, press releases, and
abstracts presented at national and international meetings were considered.
RESULTS: SGLT2 inhibitors correct a novel pathophysiological defect, have an
insulin-independent action, are efficacious with glycosylated hemoglobin
reduction ranging from 0.5% to 1.5%, promote weight loss, have a low incidence
of hypoglycemia, complement the action of other antidiabetic agents, and can be
used at any stage of diabetes. They are generally well tolerated. However, due
to side effects, such as repeated urinary tract and genital infections,
increased hematocrit, and decreased blood pressure, appropriate patient
selection for drug initiation and close monitoring after initiation will be
important. Results of ongoing clinical studies of the effect of SGLT2 inhibitors
on diabetic complications and cardiovascular safety are crucial to determine the
risk-benefit ratio. A recent decision by the Committee for Medicinal Products
for Human Use of the European Medicines Agency has recommended approval of
dapagliflozin for the treatment of type 2 diabetes as an adjunct to diet and
exercise, in combination with other glucose-lowering medicinal products,
including insulin, and as a monotherapy for metformin-intolerant patients.
Clinical research also remains to be carried out on the long-term effects of
glucosuria and other potential effects of SGLT2 inhibitors, especially in view
of the observed increase in the incidence of bladder and breast cancer. SGLT2
inhibitors represent a promising approach for the treatment of diabetes, and
could potentially be an addition to existing therapies. Canagliflozin, an oral inhibitor of sodium/glucose cotransporter 2 (SGLT2) in
the kidneys, leads to glucosuria and provides a unique mechanism to lower blood
glucose levels in diabetes. It corrects a novel pathophysiological defect, has
an insulin-independent action, reduces HbA1c by 0.5 to 1.1%, promotes weight
loss, has a low incidence of hypoglycemia, complements the action of other
antidiabetic agents, can be used at any stage of diabetes and appears to be safe
in patients with compromised renal function. Due to side effects such as urinary
tract and genital infections and decrease in blood pressure, proper patient
selection for drug initiation and close monitoring will be important. Results of
ongoing cardiovascular safety trials are important to determine the risk-benefit
ratio. Canagliflozin is the first oral SGLT2 inhibitor approved in the U.S.
market and it represents a promising approach for the treatment of diabetes in
this era of increasing obesity. AIMS: Urinary tract infection (UTI) is a common clinical problem in diabetic
patients; however, the relationship between UTI and glucosuria remains
uncertain. To investigate the relationship, we examined the effect of glucosuria
induced by sodium glucose cotransporter 2 (SGLT2) inhibitors on the progression
of UTI in mice.
METHODS: From 1 day before transurethral inoculation with Candida albicans,
female mice were treated orally once a day with an SGLT2 inhibitor in different
treatment regimens: (i) dapagliflozin at 10 mg/kg for 2, 3 or 7 days, (ii)
dapagliflozin at 0.1, 1 or 10 mg/kg for 3 days and (iii) dapagliflozin,
canagliflozin or tofogliflozin at 10 mg/kg for 3 days. To evaluate the ascending
UTI, the kidneys were removed 6 days after the inoculation, and the number of
viable C. albicans cells in kidney was measured as colony-forming units (CFU).
RESULTS: In mice treated with dapagliflozin, the number of C. albicans CFU in
kidney increased in accordance with both treatment duration and dose. The number
of CFU significantly increased when mice were treated with 10 mg/kg
dapagliflozin or canagliflozin but not tofogliflozin. With dapagliflozin and
canagliflozin, urine glucose concentration (UGC) significantly increased up to
24 h after drug administration; with tofogliflozin, UGC significantly increased
only up to 12 h after drug administration.
CONCLUSIONS: Our data indicate that increased susceptibility to UTI is
associated with a persistent increase in UGC. Treatment of type 2 diabetes (T2DM) continues to present challenges, with
significant proportion of patients failing to achieve and maintain glycemic
targets. Despite the availability of many oral antidiabetic agents, therapeutic
efficacy is offset by side effects such as weight gain and hypoglycemia.
Therefore, the search for novel therapeutic agents with an improved benefit-risk
profile continues. Recent research has focused on the kidney as a potential
therapeutic target, especially because maximal renal glucose reabsorption is
increased in T2DM. Under normal physiological conditions, nearly all filtered
glucose is reabsorbed in the proximal tubule of the nephron, principally via the
sodium-glucose cotransporter 2 (SGLT2). SGLT2-inhibitors are a new class of oral
antidiabetics, which reduce hyperglycemia by increasing urinary glucose
excretion independently of insulin secretion or action. Clinical results are
promising with significant lowering of HbA1c without increased risk of
hypoglycemia, reduction of body weight and reduction of systolic blood pressure.
Dapagliflozin is the first highly selective SGLT2-inhibitor approved by the
European Medecine Agency. Canagliflozin and empagliflozin are undergoing phase
III trials. Actual safety issues are an increased risk for genital- and urinary
tract infections and a possible increased risk for bladder and breast cancer.
This led to refusal of dapagliflozin by the Food and Drug Administration (FDA).
A large randomized control trial is therefore warranted by the FDA. This review
provides an overview of the current evidence available so far on the therapeutic
potential of the SGLT2-inhibitors for the treatment of T2DM. Type 2 diabetes is characterized by decreased insulin secretion and sensitivity.
The available oral anti-diabetic drugs act on many different molecular sites.
The most used of oral anti-diabetic agents is metformin that activates glucose
transport vesicles to the cell surface. Others are: the sulphonylureas; agents
acting on the incretin system; GLP-1 agonists; dipetidylpeptidase-4 inhibitors;
meglinitide analogues; and the thiazolidinediones. Despite these many drugs
acting by different mechanisms, glycaemic control often remains elusive. None of
these drugs have a primary renal mechanism of action on the kidneys, where
almost all glucose excreted is normally reabsorbed. That is where the inhibitors
of glucose reuptake (sodium-glucose cotransporter 2, SGLT2) have a unique site
of action. Promotion of urinary loss of glucose by SGLT2 inhibitors embodies a
new principle of control in type 2 diabetes that has several advantages with
some urogenital side-effects, both of which are evaluated in this review.
Specific approvals include use as monotherapy, when diet and exercise alone do
not provide adequate glycaemic control in patients for whom the use of metformin
is considered inappropriate due to intolerance or contraindications, or as
add-on therapy with other anti-hyperglycaemic medicinal products including
insulin, when these together with diet and exercise, do not provide adequate
glycemic control. The basic mechanisms are improved β-cell function and insulin
sensitivity. When compared with sulphonylureas or other oral antidiabetic
agents, SGLT2 inhibitors provide greater HbA1c reduction. Urogenital
side-effects related to the enhanced glycosuria can be troublesome, yet seldom
lead to discontinuation. On this background, studies are analysed that compare
SGLT2 inhibitors with other oral antidiabetic agents. Their unique mode of
action, unloading the excess glycaemic load, contrasts with other oral agents
that all act to counter the effects of diabetic hyperglycaemia. Inhibitors of sodium-glucose co-transporter type 2 (SGLT2) are proposed as a
novel approach for the management of type 2 diabetes mellitus (T2DM). Several
compounds are already available in many countries (dapagliflozin, canagliflozin,
empagliflozin and ipragliflozin) and some others are in a late phase of
development. The available SGLT2 inhibitors share similar pharmacokinetic
characteristics, with a rapid oral absorption, a long elimination half-life
allowing once-daily administration, an extensive hepatic metabolism mainly via
glucuronidation to inactive metabolites, the absence of clinically relevant
drug-drug interactions and a low renal elimination as parent drug. SGLT2
co-transporters are responsible for reabsorption of most (90 %) of the glucose
filtered by the kidneys. The pharmacological inhibition of SGLT2 co-transporters
reduces hyperglycaemia by decreasing renal glucose threshold and thereby
increasing urinary glucose excretion. The amount of glucose excreted in the
urine depends on both the level of hyperglycaemia and the glomerular filtration
rate. Results of numerous placebo-controlled randomised clinical trials of
12-104 weeks duration have shown significant reductions in glycated haemoglobin
(HbA1c), resulting in a significant increase in the proportion of patients
reaching HbA1c targets, and a significant lowering of fasting plasma glucose
when SGLT2 inhibitors were administered as monotherapy or in addition to other
glucose-lowering therapies including insulin in patients with T2DM. In
head-to-head trials of up to 2 years, SGLT2 inhibitors exerted similar
glucose-lowering activity to metformin, sulphonylureas or sitagliptin. The
durability of the glucose-lowering effect of SGLT2 inhibitors appears to be
better; however, this remains to be more extensively investigated. The risk of
hypoglycaemia was much lower with SGLT2 inhibitors than with sulphonylureas and
was similarly low as that reported with metformin, pioglitazone or sitagliptin.
Increased renal glucose elimination also assists weight loss and could help to
reduce blood pressure. Both effects were very consistent across the trials and
they represent some advantages for SGLT2 inhibitors when compared with other
oral glucose-lowering agents. The pharmacodynamic response to SGLT2 inhibitors
declines with increasing severity of renal impairment, and prescribing
information for each SGLT2 inhibitor should be consulted regarding dosage
adjustments or restrictions in moderate to severe renal dysfunction. Caution is
also recommended in the elderly population because of a higher risk of renal
impairment, orthostatic hypotension and dehydration, even if the absence of
hypoglycaemia represents an obvious advantage in this population. The overall
effect of SGLT2 inhibitors on the risk of cardiovascular disease is unknown and
will be evaluated in several ongoing prospective placebo-controlled trials with
cardiovascular outcomes. The impact of SGLT2 inhibitors on renal function and
their potential to influence the course of diabetic nephropathy also deserve
more attention. SGLT2 inhibitors are generally well-tolerated. The most
frequently reported adverse events are female genital mycotic infections, while
urinary tract infections are less commonly observed and generally benign. In
conclusion, with their unique mechanism of action that is independent of insulin
secretion and action, SGLT2 inhibitors are a useful addition to the therapeutic
options available for the management of T2DM at any stage in the natural history
of the disease. Although SGLT2 inhibitors have already been extensively
investigated, further studies should even better delineate the best place of
these new glucose-lowering agents in the already rich armamentarium for the
management of T2DM. SGLT2 (Sodium Glucose co-Transporter 2 Inhibitors) inhibitors are a new group of
oral medications for the treatment of type 2 diabetes mellitus patients. These
medications interfere with the process of glucose reabsorption in the proximal
convoluted tubules in the kidneys, therefore increasing both glucose and water
diuresis. SGLT2 inhibitors were found to be effective in lowering HbA1c levels
in double-blinded studies, both as monotherapy and in combination with other
oral hypoglycemic medications of various other mechanisms of action. SGLT2
Inhibitors are not a risk factor for hypoglycemia and are suitable for
combination with insulin therapy. Their unique mode of action, relying on
glomerular filtration, make these medication unsuitable for usage as treatment
for type 2 diabetes patients who are also suffering from moderate to severe
renal failure. Their main adverse effects are increased risk for urinary and
genital tract infections. The following review describes the relevant
pathophysiology addressed by these novel medications, evidence for efficacy and
the safety profile of SGLT2 Inhibitors. |
Is CD56 useful in Ewing sarcoma prognosis? | Excellent prognosis in a subset of patients with Ewing sarcoma identified at diagnosis by CD56 using flow cytometryIn patients with localized nonpelvic disease, those expressing low/negative CD56 had 100% PFS versus 40% in the high expressing group (P = 0.02) | A thorough literature search revealed no previous reports of this entity, and we
are the first to describe a case of a high-grade sarcoma arising from a
recurrent immature teratoma misdiagnosed as growing teratoma syndrome. The
patient was a 23-yr-old female, diagnosed at the age of 20 with a Stage IIIB
immature ovarian teratoma. After surgery and chemotherapy, the patient developed
multiple liver and pelvic masses that were diagnosed as mature teratomas based
on small samples obtained by computed tomography-guided core biopsy. Three years
after diagnosis the patient presented with severe respiratory difficulty and
following resection, the final pathology revealed multiple tumors with foci of
high grade sarcoma compatible with primitive neuroectodermal tumor/extraskeletal
Ewing sarcoma based on morphology and immunohistochemistry (CD99, CD56).
However, on the basis of further immunostaining and fluorescent in situ
hybridization studies negative for rearrangement of EWSR1, the final pathologic
diagnosis was high-grade unspecified (undifferentiated) sarcoma. This case
illustrates the pitfalls of biopsying 1 site in a patient with recurrence of a
heterogeneous tumor such as immature ovarian teratoma, especially when rendering
a benign diagnosis such as growing teratoma syndrome. It is of utmost importance
to adequately sample large-volume recurrent teratomas, and we suggest biopsying
several different sites, to increase the likelihood of detecting a maligt
component. |
What is the method FASP used for? | Filter Aided Sample Preparation (FASP), a type of proteomic reactor, in which samples dissolved in sodium dodecyl sulfate (SDS) are digested in an ultrafiltration unit. | Chlorobaculum (Cba.) tepidum is a green sulfur bacterium that oxidizes sulfide,
elemental sulfur, and thiosulfate for photosynthetic growth. To gain insight
into the sulfur metabolism, the proteome of Cba. tepidum cells sampled under
different growth conditions has been quantified using a rapid gel-free,
filter-aided sample preparation (FASP) protocol with an in-solution isotopic
labeling strategy. Among the 2245 proteins predicted from the Cba. tepidum
genome, approximately 970 proteins were detected in unlabeled samples, whereas
approximately 630-640 proteins were detected in labeled samples comparing two
different growth conditions. Wild-type cells growing on thiosulfate had an
increased abundance of periplasmic cytochrome c-555 and proteins of the
periplasmic thiosulfate-oxidizing SOX enzyme system when compared with cells
growing on sulfide. A dsrM mutant of Cba. tepidum, which lacks the dissimilatory
sulfite reductase DsrM protein and therefore is unable to oxidize sulfur
globules to sulfite, was also investigated. When compared with wild type, the
dsrM cells exhibited an increased abundance of DSR enzymes involved in the
initial steps of sulfur globule oxidation (DsrABCL) and a decreased abundance of
enzymes putatively involved in sulfite oxidation (Sat-AprAB-QmoABC). The results
show that Cba. tepidum regulates the cellular levels of enzymes involved in
sulfur metabolism and other electron-transferring processes in response to the
availability of reduced sulfur compounds. Analytical advantages of using multiple enzymes for sample digestion (MED),
primarily an increase of sequence coverage, have been reported in several
studies. However, this approach is only rarely used, mainly because it requires
additional sample and mass spectrometric measurement time. We have previously
described Filter Aided Sample Preparation (FASP), a type of proteomic reactor,
in which samples dissolved in sodium dodecyl sulfate (SDS) are digested in an
ultrafiltration unit. In FASP, such as in any other preparation protocol, a
portion of sample remains after digestion and peptide elution. Making use of
this fact, we here develop a protocol enabling consecutive digestion of the
sample with two or three enzymes. By use of the FASP method, peptides are
liberated after each digestion step and remaining material is subsequently
cleaved with the next proteinase. We observed excellent performance of the
ultrafiltration devices in this mode, allowing efficient separation of
orthogonal populations of peptides, resulting in an increase in the numbers of
identified peptides and proteins. At the low microgram level, we found that the
consecutive use of endoproteinases LysC and trypsin enabled identification of up
to 40% more proteins and phosphorylation sites in comparison to the commonly
used one-step tryptic digestion. MED-FASP offers efficient exploration of
previously unused sample material, increasing depth of proteomic analyses and
sequence coverage. Zymogen granule (ZG) constituents play important roles in pancreatic injury and
disease. In previous studies, proteomic analyses with rat zymogen granules were
separated by two-dimensional gel electrophoresis or one-dimensional SDS-PAGE,
followed by in-gel tryptic digestion. In order to overcome the disadvantage of
in-gel digestion and to carry out further in-depth proteomic analysis of the
zymogen granules, in this study, by combining a filter-aided sample preparation
method and fully automated 2D-LC-MS/MS technique, 800 ZG proteins were
identified with at least two unique peptides for each protein, 75% of which have
not been previously reported. The identified proteins revealed broad diversity
in protein identity and function. This is the largest dataset of ZG proteome,
and also the first dataset of the mouse ZG proteome, which may help elucidate on
the molecular architecture of ZGs and their functions. The expanding use of surfactants for proteome sample preparations has prompted
the need to systematically optimize the application and removal of these
MS-deleterious agents prior to proteome measurements. Here we compare four
detergent cleanup methods (trichloroacetic acid (TCA) precipitation,
chloroform/methanol/water (CMW) extraction, a commercial detergent removal spin
column method (DRS) and filter-aided sample preparation (FASP)) to provide
efficiency benchmarks with respect to protein, peptide, and spectral
identifications in each case. Our results show that for protein-limited samples,
FASP outperforms the other three cleanup methods, while at high protein amounts,
all the methods are comparable. This information was used to investigate and
contrast molecular weight-based fractionated with unfractionated lysates from
three increasingly complex samples ( Escherichia coli K-12, a five microbial
isolate mixture, and a natural microbial community groundwater sample), all of
which were prepared with an SDS-FASP approach. The additional fractionation step
enhanced the number of protein identifications by 8% to 25% over the
unfractionated approach across the three samples. The performance of two proteomic sample preparation methods, "pseudoshotgun"
(PSG) and filter-aided sample preparation (FASP) were compared in terms of the
number of identified proteins, representation of cellular component GO (gene
ontology) categories in the obtained list of proteins, and the efficiency of
both methods in the proteomic analysis of a very low number of cells. Both
methods were combined to obtain a proteomic profile of a short-term culture
(passage 3) of melanoma cells, established in our laboratory from a human
metastatic melanoma lesion. The data revealed that with FASP, usually more
proteins are identified than with PSG when analyzing a higher number of cells (≥
5000/injection), whereas PSG is favorable when analyzing only a very small
amount of cells (250-500/injection). PSG and FASP, however, are complementary
techniques, as combining both methods further increases the number of identified
proteins. Moreover, we show that it is feasible to identify a substantial number
of proteins from only 250 cells/injection that is equivalent to 60 ng of
protein. A novel form of ovomacroglobulin/ovostatin (OVOS2) predicted from EST data was
previously identified in the chicken ovarian cancer model using a mass
spectrometry-based shotgun label-free proteomics strategy. The quantitative
label-free data from plasma showed a significant increase over time with the
spontaneous onset and progression of ovarian cancer making it a potential
protein biomarker for further study. Two other proteins of interest identified
from this initial study included vitellogenin-1 (Vit-1), a lipid-transport
protein tied to egg production, and transthyretin (TTR), a retinol binding
transport protein currently used in the clinical management of ovarian cancer. A
multiplexed protein cleavage isotope dilution mass spectrometry (PC-IDMS) assay
was developed to quantify OVOS2, Vit-1, and TTR by selected reaction monitoring
(SRM). A total of 6 stable isotope labeled (SIL) peptide standards were used in
the assay with three tryptic peptides from OVOS2, one for Vit-1, and two for
TTR. The assay was developed for use with un-depleted raw plasma combined with
the filter assisted sample preparation (FASP) method and its use was also
demonstrated for matched ovary tissue samples. The PC-IDMS data for the two TTR
peptides did not correlate with each other with more than a 10-fold difference
in concentration for all 5 time points measured. The PC-IDMS data from the
longitudinal plasma samples correlated well for OVOS2 and Vit-1 whereas TTR was
inconclusive. Interestingly, the absolute amount for one of the OVOS2 SIL
peptides was 2-fold less compared with the other two SIL peptides. These data
illustrate the successes and challenges of qualifying quantitative levels of
proteins from an in-gel digestion sample preparation followed by LC-MS/MS (GeLC)
label-free discovery-based approach to a targeted SRM-based quantitative assay
in plasma and tissues. This work presents a comparative evaluation of several detergent-based sample
preparation workflows for the MS-based analysis of bacterial proteomes,
performed using the model organism Escherichia coli. Initially, RapiGest- and
SDS-based buffers were compared for their protein extraction efficiency and
quality of the MS data generated. As a result, SDS performed best in terms of
total protein yields and overall number of MS identifications, mainly due to a
higher efficiency in extracting high molecular weight (MW) and membrane
proteins, while RapiGest led to an enrichment in periplasmic and fimbrial
proteins. Then, SDS extracts underwent five different MS sample preparation
workflows, including: detergent removal by spin columns followed by in-solution
digestion (SC), protein precipitation followed by in-solution digestion in
ammonium bicarbonate or urea buffer, filter-aided sample preparation (FASP), and
1DE separation followed by in-gel digestion. On the whole, about 1000 proteins
were identified upon LC-MS/MS analysis of all preparations (>1100 with the SC
workflow), with FASP producing more identified peptides and a higher mean
sequence coverage. Each protocol exhibited specific behaviors in terms of MW,
hydrophobicity, and subcellular localization distribution of the identified
proteins; a comparative assessment of the different outputs is presented. Preserved clinical material is a unique source for proteomic investigation of
human disorders. Here we describe an optimized protocol allowing large scale
quantitative analysis of formalin fixed and paraffin embedded (FFPE) tissue. The
procedure comprises four distinct steps. The first one is the preparation of
sections from the FFPE material and microdissection of cells of interest. In the
second step the isolated cells are lysed and processed using 'filter aided
sample preparation' (FASP) technique. In this step, proteins are depleted from
reagents used for the sample lysis and are digested in two-steps using
endoproteinase LysC and trypsin. After each digestion, the peptides are
collected in separate fractions and their content is determined using a highly
sensitive fluorescence measurement. Finally, the peptides are fractionated on
'pipette-tip' microcolumns. The LysC-peptides are separated into 4 fractions
whereas the tryptic peptides are separated into 2 fractions. In this way
prepared samples allow analysis of proteomes from minute amounts of material to
a depth of 10,000 proteins. Thus, the described workflow is a powerful technique
for studying diseases in a system-wide-fashion as well as for identification of
potential biomarkers and drug targets. Primary tissue samples are valuable resources for investigators interested in
understanding disease. In order to maximize the information content that can be
gained from these precious samples, proper storage, handling, and preparation
are essential. Some tissue preservation techniques utilize the cryopreservation
medium, optimal cutting temperature (OCT) compound. While this medium provides
benefits for traditional molecular studies, certain components can interfere
with mass spectrometric analyses. Mass spectrometry based proteomics is a
growing field with many applications for disease research. Our goal is to
determine a reliable method for separating the proteins from the contaminating
species in OCT embedded samples, thus making these samples compatible with mass
spectrometric analyses. The novel applications of ether-methanol precipitation,
filter-aided sample preparation (FASP), and SDS-PAGE provide researchers with
protocols for removing OCT contaminating species from valuable samples. The
results presented in this study show that all three methods reproducibly remove
OCT; however, precipitation and FASP outperform SDS-PAGE by common proteomic
metrics. Discovery-based proteomic studies aim to answer important biological questions
by identifying as many proteins as possible. In order to accomplish this lofty
goal, an effort must be placed on determining an optimal workflow that maximizes
protein identifications. In this study, we compare protein extraction, digestion
and fractionation methods for bottom-up proteomics using a human colon cancer
cell line as our model system. Four different buffers for protein extraction,
two digestion approaches, as well as three sample fractionation methods were
evaluated in order to determine an accessible workflow that gives maximal
protein identifications. Samples comparing these workflows were analyzed via
UPLC paired with tandem MS on a Q-Exactive mass spectrometer. Our goal is to
determine an optimal workflow to enable users to maximize protein
identifications. Our results show that an increased number of confident protein
identifications are attained with a filter-aided digestion approach as compared
to an in-solution digestion. Overall SDS-PAGE fractionation leads to higher
numbers of identifications than SCX SpinTip and reverse phased cartridge
platforms. The novel aspect of this work is the comparison of two readily
available, offline platforms for fractionation in reference to a traditional
technique, SDS-PAGE. Deamidation of asparagine and glutamine residues is a common post-translational
modification. Researchers often rely on mass spectrometric based proteomic
techniques for the identification of these post-translational sites. Mass
spectral analysis of deamidated peptides is complicated and often misassigned
due to overlapping (13)C peak of the amidated form with the deamidated
monoisotopic peak; these two peaks are only separated by 19.34 mDa. For proper
assignment, it is inherently important to use a mass spectrometer with high mass
measurement accuracy and high resolving power. Herein, mouse brain tissue lysate
was prepared using filter-aided sample preparation (FASP) method and Stage Tip
fractionation followed by analysis on a oLC coupled with a quadrupole
orbitrap (Q-Exactive) mass spectrometer to accurately identify more than 5400
proteins. Mass spectral data was processed using MASCOT and ProteoIQ for
accurate identification of peptides and proteins. MASCOT search values for
precursor and MS/MS mass tolerances were investigated, and it was determined
that data searched with greater than 5 ppm precursor mass tolerance resulted in
the misassignment of deamidated peptides. Peptides that were identified with a
mass measurement accuracy of ±5 ppm were correctly assigned. In this work, for the first time, hydrazide functionalized PAMAM was designed
and synthesized for efficient and selective enrichment of N-linked glycopeptides
from complex biological samples using FASP (filter-aided sample preparation)
mode. |
What is the role of extracellular signal-related kinases 1 and 2 (ERK1/2) proteins in craniosynostosis? | Reduced dosage of ERF, which encodes an inhibitory ETS transcription factor directly bound by ERK1/2 causes complex craniosynostosis (premature fusion of the cranial sutures) in humans and mice. Features of this newly recognized clinical disorder include multiple-suture synostosis, craniofacial dysmorphism, Chiari malformation and language delay. | The extracellular signal-related kinases 1 and 2 (ERK1/2) are key proteins
mediating mitogen-activated protein kinase signaling downstream of RAS:
phosphorylation of ERK1/2 leads to nuclear uptake and modulation of multiple
targets. Here, we show that reduced dosage of ERF, which encodes an inhibitory
ETS transcription factor directly bound by ERK1/2 (refs. 2,3,4,5,6,7), causes
complex craniosynostosis (premature fusion of the cranial sutures) in humans and
mice. Features of this newly recognized clinical disorder include
multiple-suture synostosis, craniofacial dysmorphism, Chiari malformation and
language delay. Mice with functional Erf levels reduced to ∼30% of normal
exhibit postnatal multiple-suture synostosis; by contrast, embryonic calvarial
development appears mildly delayed. Using chromatin immunoprecipitation in mouse
embryonic fibroblasts and high-throughput sequencing, we find that ERF binds
preferentially to elements away from promoters that contain RUNX or AP-1 motifs.
This work identifies ERF as a novel regulator of osteogenic stimulation by
RAS-ERK signaling, potentially by competing with activating ETS factors in
multifactor transcriptional complexes. |
Are there any urine biomarkers for chronic kidney disease? | Chronic kidney disease (CKD), is a progressive loss in renal function over a period of months or years. The symptoms of worsening kidney function are non-specific, and might include feeling generally unwell and experiencing a reduced appetite. Often, chronic kidney disease is diagnosed as a result of screening of people known to be at risk of kidney problems, such as those with high blood pressure or diabetes and those with a blood relative with chronic kidney disease. Chronic kidney disease may also be identified when it leads to one of its recognized complications, such as cardiovascular disease, anemia or pericarditis. It is differentiated from acute kidney disease in that the reduction in kidney function must be present for over 3 months. | There is a strong association between both acute and chronic dysfunction of the
heart and kidneys with respect to morbidity and mortality. The complex
interrelationships of longitudinal changes in both organ systems have been
difficult to describe and fully understand due to a lack of categorization of
the common clinical scenarios where these phenomena are encountered. Thus,
cardiorenal syndromes (CRSs) have been subdivided into five syndromes which
represent clinical vignettes in which both the heart and the kidney are involved
in bidirectional injury and dysfunction via a final common pathway of
cell-to-cell death and accelerated apoptosis mediated by oxidative stress. Types
1 and 2 involve acute and chronic cardiovascular disease (CVD) scenarios leading
to acute kidney injury (AKI) or accelerated chronic kidney disease (CKD). Types
3 and 4 describe AKI and CKD, respectively, leading primarily to heart failure,
although it is possible that acute coronary syndromes, stroke, and arrhythmias
could be CVD outcomes in these forms of CRS. Finally, CRSs type 5 describe a
systemic insult to both heart and the kidneys, such as sepsis, where both organs
are injured simultaneously in persons with previously normal heart and kidney
function at baseline. Both blood and urine biomarkers, including the assessment
of catalytic iron, a critical element to the generation of oxygen-free radicals
and oxidative stress, are reviewed in this paper. Cardiorenal syndromes (CRS) have been subclassified as five defined entities
which represent clinical circumstances in which both the heart and the kidney
are involved in a bidirectional injury and dysfunction via a final common
pathway of cell-to-cell death and accelerated apoptosis mediated by oxidative
stress. Types 1 and 2 involve acute and chronic cardiovascular disease (CVD)
scenarios leading to acute kidney injury or accelerated chronic kidney disease.
Types 2 and 3 describe acute and chronic kidney disease leading primarily to
heart failure, although it is possible that acute coronary syndromes, stroke,
and arrhythmias could be CVD outcomes in these forms of CRS. Finally, CRS type 5
describes a simultaneous insult to both heart and kidneys, such as sepsis, where
both organs are injured simultaneously. Both blood and urine biomarkers are
reviewed in this paper and offer a considerable opportunity to enhance the
understanding of the pathophysiology and known epidemiology of these recently
defined syndromes. A growing number of patients are recognised to have chronic kidney disease
(CKD). However, only a minority will progress to end-stage renal disease
requiring dialysis or transplantation. Currently available diagnostic and
staging tools frequently fail to identify those at higher risk of progression or
death. Furthermore within specific disease entities there are shortcomings in
the prediction of the need for therapeutic interventions or the response to
different forms of therapy. Kidney and urine proteomic biomarkers are considered
as promising diagnostic tools to predict CKD progression early in diabetic
nephropathy, facilitating timely and selective intervention that may reduce the
related health-care expenditures. However, independent groups have not validated
these findings and the technique is not currently available for routine clinical
care. Furthermore, there are gaps in our understanding of predictors of
progression or need for therapy in non-diabetic CKD. Presumably, a combination
of tissue and urine biomarkers will be more informative than individual markers.
This review identifies clinical questions in need of an answer, summarises
current information on proteomic biomarkers and CKD, and describes the European
Kidney and Urine Proteomics initiative that has been launched to carry out a
clinical study aimed at identifying urinary proteomic biomarkers distinguishing
between fast and slow progressors among patients with biopsy-proven primary
glomerulopathies. INTRODUCTION: Conventional markers of acute kidney injury (AKI) lack diagnostic
accuracy and are expressed only late after cardiac surgery with cardiopulmonary
bypass (CPB). Recently, interest has focused on hepcidin, a regulator of iron
homeostasis, as a unique renal biomarker.
METHODS: We studied 100 adult patients in the control arm of a randomized,
controlled trial http://www.clinicaltrials.gov/NCT00672334 who were identified
as being at increased risk of AKI after cardiac surgery with CPB. AKI was
defined according to the Risk, Injury, Failure, Loss, End-stage renal disease
classification of AKI classification stage. Samples of plasma and urine were
obtained simultaneously (1) before CPB (2) six hours after the start of CPB and
(3) twenty-four hours after CPB. Plasma and urine hepcidin 25-isoforms were
quantified by competitive enzyme-linked immunoassay.
RESULTS: In AKI-free patients (N = 91), urine hepcidin concentrations had
largely increased at six and twenty-four hours after CPB, and they were three to
seven times higher compared to patients with subsequent AKI (N = 9) in whom
postoperative urine hepcidin remained at preoperative levels (P = 0.004, P =
0.002). Furthermore, higher urine hepcidin and, even more so, urine hepcidin
adjusted to urine creatinine at six hours after CPB discriminated patients who
did not develop AKI (area under the curve (AUC) receiver operating
characteristic curve 0.80 [95% confidence interval (95% CI) 0.71 to 0.87] and
0.88 [95% CI 0.78 to 0.97]) or did not need renal replacement therapy initiation
(AUC 0.81 [95% CI 0.72 to 0.88] 0.88 [95% CI 0.70 to 0.99]) from those who did.
At six hours, urine hepcidin adjusted to urine creatinine was an independent
predictor of ruling out AKI (P = 0.011). Plasma hepcidin did not predict no
development of AKI. The study findings remained essentially unchanged after
excluding patients with preoperative chronic kidney disease.
CONCLUSIONS: Our findings suggest that urine hepcidin is an early predictive
biomarker of ruling out AKI after CPB, thereby contributing to early patient
risk stratification. Acute kidney injury (AKI) in hospitalized patients is independently associated
with increased morbidity and mortality in pediatric and adult populations.
Continued reliance on serum creatinine and urine output to diagnose AKI has
resulted in our inability to provide successful therapeutic and supportive
interventions to prevent and mitigate AKI and its effects. Research efforts over
the last decade have focused on the discovery and validation of novel urinary
biomarkers to detect AKI prior to a change in kidney function and to aid in the
differential diagnosis of AKI. The aim of this article is to review the AKI
biomarker literature with a focus on the context in which they should serve to
add to the clinical context facing physicians caring for patients with, or
at-risk for, AKI. The optimal and appropriate utilization of AKI biomarkers will
only be realized by understanding their characteristics and placing reasonable
expectations on their performance in the clinical arena. CONTEXT: Kidney-related pathologies have increasing prevalence rates, produce a
considerable ficial burden, and are characterized by elevated levels of
oxidative stress (OS).
OBJECTIVE: This review examines relationships between chronic kidney disease
(CKD) and markers of OS and antioxidant status (AS).
METHODS: A systematic review of MEDLINE-indexed clinical trials, randomized
controlled trials and comparative studies that examined OS and AS was performed.
RESULTS AND CONCLUSION: Several markers emerged as well-suited indicators of OS
and AS in CKD: malondialdehyde, F2-isoprostanes, lipid hydroperoxides,
asymmetric dimethylarginine, 8-oxo-7,8-dihydro-2'-deoxyguanosine, protein
carbonyls, advanced oxidation protein products and glutathione-related activity. Novel biomarkers may improve our ability to predict which patients with chronic
kidney disease (CKD) are at higher risk for progressive loss of renal function.
Here, we assessed the performance of urine neutrophil gelatinase-associated
lipocalin (NGAL) for outcome prediction in a diverse cohort of 3386 patients
with CKD in the Chronic Renal Insufficiency Cohort study. In this cohort, the
baseline mean estimated glomerular filtration rate (eGFR) was 42.4 ml/min per
1.73 m(2), the median 24-h urine protein was 0.2 g/day, and the median urine
NGAL concentration was 17.2 ng/ml. Over an average follow-up of 3.2 years, there
were 689 cases in which the eGFR was decreased by half or incident end-stage
renal disease developed. Even after accounting for eGFR, proteinuria, and other
known CKD progression risk factors, urine NGAL remained a significant
independent risk factor (Cox model hazard ratio 1.70 highest to lowest
quartile). The association between baseline urine NGAL levels and risk of CKD
progression was strongest in the first 2 years of biomarker measurement. Within
this time frame, adding urine NGAL to a model that included eGFR, proteinuria,
and other CKD progression risk factors led to net reclassification improvement
of 24.7%, but the C-statistic remained nearly identical. Thus, while urine NGAL
was an independent risk factor of progression among patients with established
CKD of diverse etiology, it did not substantially improve prediction of outcome
events. BACKGROUND: Chronic kidney disease (CKD) affects up to 16% of the adult
population and is associated with significant morbidity and mortality. People at
highest risk from progressive CKD are defined by a sustained decline in
estimated glomerular filtration rate (eGFR) and/or the presence of significant
albuminuria/proteinuria and/or more advanced CKD. Accurate mapping of the
bio-clinical determits of this group will enable improved risk stratification
and direct the development of better targeted management for people with CKD.
METHODS/DESIGN: The Renal Impairment In Secondary Care study is a prospective,
observational cohort study, patients with CKD 4 and 5 or CKD 3 and either
accelerated progression and/or proteinuria who are managed in secondary care are
eligible to participate. Participants undergo a detailed bio-clinical assessment
that includes measures of vascular health, periodontal health, quality of life
and socio-economic status, clinical assessment and collection of samples for
biomarker analysis. The assessments take place at baseline, and at six, 18, 36,
60 and 120 months; the outcomes of interest include cardiovascular events,
progression to end stage kidney disease and death.
DISCUSSION: The determits of progression of chronic kidney disease are not
fully understood though there are a number of proposed risk factors for
progression (both traditional and novel). This study will provide a detailed
bio-clinical phenotype of patients with high-risk chronic kidney disease (high
risk of both progression and cardiovascular events) and will repeatedly assess
them over a prolonged follow up period. Recruitment commenced in Autumn 2010 and
will provide many outputs that will add to the evidence base for progressive
chronic kidney disease. BACKGROUND: The Canadian Study of Prediction of Death, Dialysis and Interim
Cardiovascular Events (CanPREDDICT) is a large, prospective, pan-Canadian,
cohort study designed to improve our understanding of determits of renal and
cardiovascular (CV) disease progression in patients with chronic kidney disease
(CKD). The primary objective is to clarify the associations between traditional
and newer biomarkers in the prediction of specific renal and CV events, and of
death in patients with CKD managed by nephrologists. This information could then
be used to better understand biological variation in outcomes, to develop
clinical prediction models and to inform enrolment into interventional studies
which may lead to novel treatments.
METHODS/DESIGNS: Commenced in 2008, 2546 patients have been enrolled with eGFR
between 15 and 45 ml/min 1.73m2 from a representative sample in 25 rural, urban,
academic and non academic centres across Canada. Patients are to be followed for
an initial 3 years at 6 monthly intervals, and subsequently annually.
Traditional biomarkers include eGFR, urine albumin creatinine ratio (uACR),
hemoglobin (Hgb), phosphate and albumin. Newer biomarkers of interest were
selected on the basis of biological relevance to important processes, commercial
availability and assay reproducibility. They include asymmetric dimethylarginine
(ADMA), N-terminal pro-brain natriuretic peptide (NT-pro-BNP), troponin I,
cystatin C, high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL6) and
transforming growth factor beta 1 (TGFβ1). Blood and urine samples are collected
at baseline, and every 6 monthly, and stored at -80°C. Outcomes of interest
include renal replacement therapy, CV events and death, the latter two of which
are adjudicated by an independent panel.
DISCUSSION: The baseline distribution of newer biomarkers does not appear to
track to markers of kidney function and therefore may offer some discriminatory
value in predicting future outcomes. The granularity of the data presented at
baseline may foster additional questions.The value of the cohort as a unique
resource to understand outcomes of patients under the care of nephrologists in a
single payer healthcare system cannot be overstated. Systematic collection of
demographic, laboratory and event data should lead to new insights. The mean age
of the cohort was 68 years, 90% were Caucasian, 62% were male, and 48% had
diabetes. Forty percent of the cohort had eGFR between 30-45 mL/min/1.73m², 22%
had eGFR values below 20 mL/min/1.73m²; 61% had uACR < 30. Serum albumin,
hemoglobin, calcium and 25-hydroxyvitamin D (25(OH)D) levels were progressively
lower in the lower eGFR strata, while parathyroid hormone (PTH) levels
increased. Cystatin C, ADMA, NT-proBNP, hsCRP, troponin I and IL-6 were
significantly higher in the lower GFR strata, whereas 25(OH)D and TGFβ1 values
were lower at lower GFR. These distributions of each of the newer biomarkers by
eGFR and uACR categories were variable. In the current study, we measured urinary angiotensinogen (AGT) through
enzyme-linked immunoadsordent assay (ELISA) and analyzed its correlation with
intrarenal renin-angiotensin system (RAS) activity in 128 chronic kidney disease
(CKD) patients. Urinary and plasma renin activity, AGT, angiotensin II (Ang II)
and aldosterone levels were also measured by radioimmunoassay (RIA) or ELISA in
these participants. Further, the expression level of intrarenal renin, AGT, Ang
II and Ang II receptors were examined by immunohistochemistry staining (IHCS) in
72 CKD patients. Their correlations with urinary AGT were also analyzed. We
found that the urinary AGT level was positively correlated with hypertension (ρ
= 0.28, P < 0.01), urinary protein (r = 0.38, P < 0.01), urinary Ang II (r =
0.29, P < 0.05), urinary type IV collagen (Col IV) (r = 0.56, P < 0.01), and was
negatively correlated with estimated glomerular filtration rate (eGFR) (r =
-0.28, P < 0.01), urinary sodium (r = -0.22, P < 0.05) and serum AGT (r = -0.27,
P < 0.01). Multiple regression analysis indicated low serum AGT (P < 0.01), high
urinary protein (P < 0.01), high urinary Ang II (P < 0.05) and high urinary Col
IV (P < 0.01) were correlated significantly with high urinary AGT. Urinary AGT
level was positively correlated with intrarenal expression level of AGT (ρ =
0.46, P < 0.01), Ang II (ρ = 0.56, P < 0.01) and Ang II type 1 receptor (ρ =
0.32, P < 0.01), as detected by IHCS. Together, these data suggest that urinary
AGT might be a potential biomarker of intrarenal RAS and Ang II activities in
CKD patients. BACKGROUND: The inclining incidence of chronic kidney disease which has led to
high mortality and immense medical burden over the past decades has become a
distressing concern in epidemiology. Unfortunately, the number of biomarkers
that allow the monitoring of chronic kidney disease (CKD) is limited. Neutrophil
gelatinase-associated lipocalin (NGAL) is an emerging biomarker which has been
shown to be able to diagnose kidney injuries.
METHODS: Eighty-one nondiabetic patients with chronic kidney disease, stage 2 to
5, were recruited for this study, and 17 healthy volunteers with eGFR greater
than 90 mL/minute/1.73m(2) were selected as the control group.
RESULTS: Our study demonstrated that the pNGAL level is elevated during CKD, and
the pNGL level has a strong correlation with the concentration of sCr and eGFR.
CONCLUSIONS: Plasma neutrophil gelatinase-associated lipocalin is a potent tool
in the diagnosis of chronic kidney diseases and is shown to have high
correlation with serum creatinine and estimated glomerular filtration rate. Inflammation is a common phenotype for cardiometabolic disorders. In this study,
we attempted to investigate inter-relationships between metabolic syndrome
(MetS), C-reactive protein (an inflammatory biomarker) and chronic kidney
disease (CKD). We performed a cross-sectional analysis of data from a
representative sample of 4425 Chinese adults in Taiwan. The MetS was defined by
a unified criteria set by several major organizations. A CKD event was defined
as an estimated glomerular filtration rate (eGFR) <60 mL/min per 1.73 m(2).
Additionly, a CRP cutpoint of 3 mg/L was used to differentiate high and low CRP
levels. Overall, 1000 participants had MetS, resulting in a prevalence rate of
22.6%. High CRP level was noted in 782 (17.6%) subjects. In addition, a total of
508 (11.5%) persons qualified as having CKD. Subjects with the MetS had
1.55-fold [95% confidence interval (CI), 1.03-2.32] increased odds of CKD
compared with their counterparts without the MetS after multiple adjustments. In
addition, there was a significantly graded relationship between increasing
levels of serum CRP and prevalent CKD (p for trend = 0.001). Participants in the
highest category of serum CRP had a significantly elevated odds of CKD as
compared with those in the lowest category [odds ratio (OR), 1.60; 95% CI,
1.21-2.12]. However, there was no interaction in excess of additive scale
between the presence of MetS and high CRP level (p = 0.83). These findings
suggest that MetS and high CRP were independently associated with increased
prevalence of CKD in Chinese adults. Liver-type fatty acid binding protein (L-FABP) is a 14kDa protein found in the
cytoplasm of human renal proximal tubules. Fatty acids are bound with L-FABP and
transported to the mitochondria or peroxisomes, where fatty acids are
beta-oxidized, and this may play a role in fatty acid homeostasis. Moreover,
L-FABP has high affinity and capacity to bind long-chain fatty acid oxidation
products, and may be an effective endogenous antioxidant. Renal L-FABP is rarely
expressed in the kidneys of rodents. In order to evaluate the pathological
dynamics of renal L-FABP in kidney disease, human L-FABP chromosomal transgenic
mice were generated. Various stress, such as massive proteinuria, hyperglycemia,
hypertension, and toxins overloaded in the proximal tubules were revealed to
up-regulate the gene expression of renal L-FABP and increase the excretion of
L-FABP derived from the proximal tubules into urine. In clinical studies of
chronic kidney disease (CKD), urinary L-FABP accurately reflected the degree of
tubulointerstitial damage and correlated with the rate of CKD progression.
Furthermore, a multicenter trial has shown that urinary L-FABP is more sensitive
than urinary protein in predicting the progression of CKD. With respect to
diabetic nephropathy and acute kidney disease (AKI), urinary L-FABP is an early
diagnostic of kidney disease or a predictive marker for renal prognosis. After
many clinical studies, urinary L-FABP was approved as a new tubular biomarker
promulgated by the Ministry of Health, Labour and Welfare in Japan. BACKGROUND: Urine albumin is the primary biomarker for detection and monitoring
of kidney damage. Because fixed decision criteria are used to identify patients
with increased values, we investigated if commonly used routine measurement
procedures gave comparable results.
METHODS: Results from 17 commercially available urine albumin measurement
procedures were investigated vs an isotope dilution mass spectrometry (IDMS)
procedure. Nonfrozen aliquots of freshly collected urine from 332 patients with
chronic kidney disease, diabetes, cardiovascular disease, and hypertension were
distributed to manufacturers to perform urine albumin measurements according to
the respective instructions for use for each procedure. Frozen aliquots were
used for measurements by the IDMS procedure. An error model was used to
determine imprecision and bias components.
RESULTS: Median differences between the largest positive and negative biases vs
IDMS were 45%, 37%, and 42% in the concentration intervals of 12-30 mg/L, 31-200
mg/L, and 201-1064 mg/L, respectively. Biases varied with concentration for most
procedures and exceeded ± 10% over the concentration interval for 14 of 16
quantitative procedures. Mean biases ranged from -35% to 34% at 15 mg/L.
Dilution of samples with high concentrations introduced bias for 4 procedures.
The combined CV was >10% for 5 procedures. It was not possible to estimate total
error due to dependence of bias on concentration. CVs for sample-specific
influences were 0% to 15.2%.
CONCLUSIONS: Bias was the domit source of disagreement among routine
measurement procedures. Consequently, standardization efforts will improve
agreement among results. Variation of bias with concentration needs to be
addressed by manufacturers. In patients with resistant hypertension (RH) we investigated the importance of
urinary neutrophil gelatinase-associated lipocalin (uNGAL- a chemiluminescent
microparticle immunoassay (CMIA) method became using (Abbott Diagnostics) for
the measurement of NGAL in urine samples) and incidence of chronic kidney
disease using the Modification of Diet in Renal Disease Study (MDRD) and Chronic
Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in estimating
glomerular filtration rate (eGFR) based on standardised serum creatinine method
traceable to isotope dilution mass spectrometry (IDMS) method. It would have
been difficult to predict that levels of these biomarker would perform better
organ damage than traditional measurements of kidney function such as
standardised serum creatinine, MDRD, or CKD-EPI equations in special population
such as RH. Serum creatinine concentrations were measured in 50 patients
(24M:26F from RH Registar in Clinical Hospital Merkur) by the kinetic Jaffe
method. There were no significant differences between the GFR values derived by
MDRD and CKD-EPI equations in the group of patients with RH. 62% of patients
have eGFR > 60 mL/minl/1.73 m2, while a 38% of patients have eGFR < 60
mL/min/1.73 m2. The measurement of NGAL in urine samples of 40 patients with RH
showed no difference and seems to be of no use in further determination of renal
impairement. Higher value of uNGAL in some resistant hypertension patients could
have link in the repair stage after AKI and would reveal pathways that could
link AKI and CKD. End-stage renal disease (ESRD) requires for its treatment permanent dialysis or
kidney transplantation (KT). KT is the best clinical treatment, however, the
early function of the allograft varies depending on multiple factors associated
with cold ischemia time (CIT) and the allograft rejection process. It is known
that serum creatinine is an insensitive and late marker for predicting graft
recovery after KT, mainly in patients with delayed graft function (DGF).
Neutrophil gelatinase-associated lipocalin (NGAL) is produced in the distal
nephron and it is one of the most promising novel biomarkers for acute kidney
injury (AKI) and chronic kidney disease (CKD). NGAL has been proposed to be a
predictor of organ recovery from DGF after KT from donors after cardiac death.
Because nonrenal diseases can also induce NGAL, more information is necessary to
validate the sensitivity and specificity of urine and plasma NGAL in clinical
samples. The exosomes are vesicles released into the urine from the kidney
epithelium and they have been proposed as better source to explore as biomarker
of renal dysfunction. The molecular composition of the urinary exosomes could be
representative of the physiological or physiopathologic condition of the urinary
system. We propose that determination of NGAL in urinary exosomes is a better
predictor of kidney dysfunction after KT than other urinary fractions. We
analyzed 15 kidney allograft recipients, with a mean age of 36 years (range,
16-60 years) and 75% were male: 11 living donors (LD) and 4 deceased donors
(DD). The average length of CIT was 14 hours in DD and less than 1 hour in LD.
Three patient developed DGF. Using Western blot analysis, NGAL was detectable in
the cellular and exosomal fraction of the urine. The exosomes expressed higher
levels of NGAL than the cellular fraction. The expression of NGAL was observed
from the first day after transplantation. In the cellular fraction of the urine,
no significant differences of NGAL were observed between the patients. However,
the median of NGAL expression in the exosomes fraction was significantly higher
in DD patient, from the first day after KT (P < .05). Moreover, we noticed that
NGAL expression in exosomes remained elevated in the patients with DGF compared
with non-DGF patients (P < .05). Considering the highest abundance of NGAL in
the urinary exosomes and its correlation with DGF patients, we suggest the
exosomal fraction as a more sensitive substrate to evaluate early biomarkers of
DGF after KT. |
What is being measured with an accelerometer in back pain patients | Accelerometer assessment measuring overall physical activity (PAL), constant strain postures (CSP), standing time (ST) and lying time (LT)...
The following parameters of physical activity were recorded: time upright (standing or walking), time standing, time walking, and step count. | We studied the temporal relationship between pain and activity in patients with
acute or chronic low back pain. We studied 15 patients with acute low back pain
and 15 patients with chronic low back pain over 3 wk. The activity levels were
collected automatically using a wrist accelerometer and were sampled every
minute. The pain levels were recorded at least every 90 min using a pocket-sized
electronic diary. The time series from each patient were then analyzed using the
cross-correlation function at various time offsets. We found that during the
first 7 days of acute low back pain, there was a significant (P < 0.01) degree
of cross-correlation between activity and pain. On average, pain followed
activity by approximately 30 min. As these patients improved and reported less
pain, the relationship between activity and pain disappeared. There was no such
relationship at any point among the patients with chronic low back pain. BACKGROUND: In LBP patients, the relationship between pain and physical activity
remains unclear. Whereas a negative relationship between pain and self-reported
physical activity was found, this relation disappeared in the case of overt
behavioral data (e.g., accelerometer). Cognitive-behavioral models of the
development of chronic pain suggest subgroups with signs of physical underuse
and overuse.
AIMS: To examine if patients with pain-related adaptive, endurance and
fear-avoidance coping differ in pain, self-reported physical function and overt
physical activity 6 months after disc surgery.
METHODS: 24 patients completed questionnaires (Von Korff chronic pain grade
(CPG), Kiel pain inventory (KPI), Funktionsfragebogen Hannover-Rücken FFbH-R)
and underwent an 8-h accelerometer assessment in their daily life (physical
activity level (PAL), number of constant postures (CP)). The KPI differed
between adaptive coping (AC) (N=9), fear avoidance coping (FAC) (N=1) and
endurance coping (EC) (N=14).
RESULTS: In the whole group, pain intensity was negative related to
self-reported physical activity whereas PAL and CP displayed no correlation with
pain. EC patients showed significantly higher pain scores and lower
self-reported physical functioning compared to AC but the same level of PAL and
furthermore, a significantly higher number of CPs in daily life. The visual
inspection of the FAC patient revealed also high pain, low physical functioning
and low overt physical activity.
CONCLUSIONS: The assessment of pain-related coping modes yielded an important
differentiation between subgroups of LBP patients 6 months after surgery.
Endurance copers displayed signs of overuse in their daily behavior in spite of
pain than adaptive copers. The one fear avoidance coper tends to do less
physical activity in the sense of underuse. There may be a relationship between sleep and pain in patients with chronic back
pain. We collected day-time pain and nighttime activity data from 18 patients
diagnosed with chronic back pain. The patients were followed for 6 days and 5
nights. Pain levels were collected every 90 min between 0800 hours and 2,200
hours using a computerized electronic diary. Activity levels were collected
using a wrist accelerometer (Actiwatch AW-64). The Actiwatch sampled activity
counts every 1 min. Patients were asked to wear the Actiwatch on their
non-domit arm. The pain level measurements were interpolated using cubic
splines. A mean pain level was calculated for each period 0800 hours to 2,200
hours as well as for the 6-day period. The difference between the mean pain
levels for the 6-day period and each 0800 hours to 2,200 hours period was
calculated for each patient. Nighttime activity data were analyzed using the
Actiwatch Sleep Analysis software. Correlations were calculated between the
Actiwatch Sleep Analysis variables and the mean pain level differences for each
patient and period. The correlation analysis was performed with SPSS 7.5. We
were unable to show any significant relationships.A different approach to
analyze the data was used. A Self-Organizing Map (SOM) Neural Network was
trained using the original nighttime activity level time series from 10 randomly
selected patients. Recall was then performed on all the activity level data.
Correlations were calculated between the pain level variance for the 6-day
period for each patient and the corresponding difference in the SOM output
coordinates. The correlation was found to be r = 0.73, p < 0.01). We conclude
that daytime pain levels are not directly correlated with sleep in the following
night and that sleep is not directly correlated with daytime pain levels on the
following day in this group of patients. There appears to be a correlation
between the difference in nighttime activity levels and patterns and the daytime
pain variance. Patients who experience large fluctuations in daytime pain levels
also show a higher variability in their nighttime activity levels and patterns.
Even though we were unable to show a direct relationship between daytime pain
and sleep, it may be reasonable to assume that better pain control resulting in
less daytime pain fluctuations can provide more stable nighttime activity levels
and patterns in this limited group of patients. By using a neural network model,
we were able to extract information from the nighttime activity levels even
though a traditional statistical analysis was unsuccessful. BACKGROUND: Normalization of activities in daily living is an important goal in
rehabilitation treatment of chronic lower back pain (CLBP) patients. Clinicians
indicate that CLBP patients often show deconditioning but also CLBP patients who
seem to be too active are seen. The objective of the present cross-sectional
study was to gain more insight into the daily activity pattern of CLBP patients
compared to controls, using accelerometry.
METHODS: Daily activities were assessed by measuring body movement with a
tri-axial accelerometer that was worn for seven consecutive days during waking
hours. Measurements were performed in the daily environment (in-doors and
out-doors) of the participant. Differences between activity level, time of day
and work status were tested.
RESULTS: Data were obtained from 29 CLBP patients and 20 controls. Results show
that the overall activity levels of patients (mean 0.75; SD 0.43) are not
significantly different from those of controls (mean 0.71; SD 0.44). However,
patients show significantly higher activity levels in the morning (p<0.001) and
significantly lower activity levels in the evening (p<0.01) compared to
controls. No significant differences in activity levels were found between
leisure time and working days within either group; furthermore no significant
differences in activity levels were found between patients with different work
status.
CONCLUSION: Overall activity levels do not differ significantly between CLBP
patients and controls, but the distribution of activities over the day differs
significantly. BACKGROUND: The present study aims to determine the time spent in different
static trunk postures during a typical working day of workers in a special
school for the severe handicaps.
METHODS: Eighteen workers with low back pain (LBP) and fifteen asymptomatic
workers were recruited. A cross-sectional design was employed to study the time
spent in different static trunk postures which was recorded by a biaxial
accelerometer attached to the T12 level of the back of the subjects.
RESULTS: The results of ANCOVA revealed that subjects with LBP spent
significantly longer percentage of time in static trunk posture when compared to
normal (p < 0.05). It was also shown that they spent significantly longer time
in trunk flexion for more than 10 degrees (p < 0.0125).
CONCLUSION: An innovative method has been developed for continuous tracking of
spinal posture, and this has potential for widespread applications in the
workplace. The findings of the present investigation suggest that teachers in
special schools are at increased risk of getting LBP. In order to minimise such
risk, frequent postural change and awareness of work posture are recommended. The aim of this cross-sectional pilot-study was to investigate the relationship
between psychological distress and free-living physical activity (PA) in
individuals with chronic low back pain (CLBP). Thirty-eight participants with
non-specific CLBP (29=distressed; 9=non-distressed) were recruited. PA levels
were measured using an accelerometer (activPAL activity monitor) over a one week
period. The following parameters of physical activity were recorded: time
upright (standing or walking), time standing, time walking, and step count.
Psychological distress was assessed using a modified version of the distress
risk assessment method (DRAM) which is a combination of somatic anxiety and
depressive symptoms. The Distressed group spent significantly less time upright
over a mean 24h day (-1.47h, 95% CI -2.70 to -0.23h, p<0.05), attributable to
1.01h less standing and 0.46h less walking. Depressive symptoms were a
statistically significant independent predictor of time upright (beta=-0.49,
p<0.05). This pilot-study found that individuals with CLBP and elevated levels
of distress spend less time upright than their non-distressed counterparts.
Clinically, when treating individuals with CLBP and elevated distress levels,
free-living PA may be low and interventions aimed at increasing upright activity
may be appropriate. In patients with low back pain (LBP), physical functioning may be negatively
influenced by both expectations on pain and pain-related fear. It is unclear
whether these factors influence both physical functioning in the laboratory as
well as in daily life. The aim of this study was to test if a combination of
persistent overprediction of pain and fear of movement predicts lab-based
performance and whether these factors are relevant for predicting daily-life
functioning. One hundred and twenty four patients with subacute LBP performed a
laboratory-based performance test twice. Maximum voluntary contraction, pre-test
pain expectations, perceived pain during testing and fear of movement were
measured. Patients were classified as correct or incorrect predictors, based on
differences between expected and perceived pain on the second attempt. Next,
physical activity in daily life was measured with an accelerometer. In
explaining physical functioning in the laboratory and in daily life an
interaction effect between fear and pain prediction was observed. In
overpredictors, fear was negatively associated with lab-based performance
(beta=-0.48, p<0.01), and positively associated with daily-life functioning
(beta=0.50, p<0.05). No significant association between fear and performance or
daily-life functioning were found in correct predictors. In contrast to correct
predictors, in overpredictors lab-based performance and daily-life functioning
was additionally explained by fear of movement. Thus it appears that fear of
movement is only predictive of performance in patients with LBP who
simultaneously overpredict the consequences of movements in terms of
painfulness. Patients with chronic pain may have difficulties estimating their own physical
activity level in daily life. Pain-related factors such as depression and pain
intensity may affect a patients' ability to estimate their own daily life
activity level. This study evaluates whether patients with Chronic Low Back Pain
(CLBP) who are more depressed and/or report more pain indeed have a lower
objectively assessed daily life activity level or whether they only perceive
their activity level as lower. Patients with CLBP were included in a
cross-sectional study. During 14days physical activity in daily life was
measured, with both an electronic diary and an accelerometer. Multilevel
analyses were performed to evaluate whether a higher level of depression and/or
pain intensity was associated with a lower objectively assessed activity level
or the discrepancy between the self-reported and objectively assessed daily life
activity levels. Results, based on 66 patients with CLBP (mean RDQ score 11.8),
showed that the objectively assessed daily life activity level is not associated
with depression or pain intensity. There was a moderate association between the
self-reported and objectively assessed activity levels (beta=0.39, p<0.01). The
discrepancy between the two was significantly and negatively related to
depression (beta=-0.19, p=0.01), indicating that patients who had higher levels
of depression judged their own activity level to be relatively low compared to
their objectively assessed activity level. Pain intensity was not associated
with the perception of a patient's activity level (beta=0.12, ns). OBJECTIVE: To compare self-report measures of daily activities with objective
activity data to determine whether patients with chronic lower back pain report
their activity levels as accurately as controls do.
DESIGN: A cross-sectional study was performed in patients and controls.
SETTING: The study was carried out in the daily environment of the subjects.
SUBJECTS: Thirty-two chronic lower back pain patients with symptoms more than
three months and 20 healthy controls from the Netherlands, aged 18-65 years.
MAIN MEASURES: A tri-axial accelerometer was worn for five weekdays and the
Baecke Physical Activity Questionnaire was filled in. Pearson's correlation was
calculated to get insight in the awareness of patients and controls. Comparisons
of the relationship between the objective and subjective scores of each
individual patient with those of the group of controls were used to allocate
each patient into subgroups: overestimators, underestimators and aware patients.
Physical and psychological characteristics of these groups were explored.
RESULTS: Patients showed weak correlations between the objective and subjective
scores of physical activity and appear to have problems in estimating their
activity levels (r = -0.27), in contrast to controls who showed strong
correlations between the objective and subjective scores (r = 0.66). Comparison
of the individual relationships of patients with those of controls showed that
44% of the patients were not aware of their activity level. There were
relatively more underestimators (30%) than overestimators (14%). Physical
characteristics between the three groups tended to be different.
CONCLUSIONS: Patient self-reports about their activity level are relatively
inaccurate when compared to objective measurements. PURPOSE: This study examines the relationship between low back pain, disability
and fatigue and overt physical activity with respect to fear-avoidance and
endurance-related subgroups.
METHOD: 49 patients completed questionnaires (Pain, Disability, Fatigue,
Depression, Pain-responses pattern) 6 months after lumbar disc surgery and
underwent an 8-hour accelerometer assessment measuring overall physical activity
(PAL), constant strain postures (CSP), standing time (ST) and lying time (LT).
Four subgroups, representing patterns of distress-endurance (DER),
eustress-endurance (EER), fear-avoidance (FAR) and adaptive responses (AR) due
to the avoidance-endurance model of pain-regulation were investigated.
RESULTS: Multivariate analyses of covariance revealed significantly higher pain,
disability and fatigue in FAR compared to AR patients and, as expected lower PAL
and CSP in FAR than in endurance patients. Both endurance groups revealed higher
pain accompanied by higher accelerometer-based physical activity (PAL, CSP) than
AR and FAR patients. Most of the subgroup differences displayed moderate to high
effect sizes.
CONCLUSIONS: The results indicate different pathways to chronic pain and
disability with physical underuse in FAR patients and overuse/overload in
endurance patients suggesting the need for individually targeted
cognitive-behavioral treatments in the maladaptive groups. Implications for
Rehabilitation Improving the return to a normal physical activity level is an
important goal for the rehabilitation of patients after lumbar disc surgery.
Different pathways to chronic pain and disability with physical underuse in
fear-avoidance patients and overuse in endurance patients should be considered.
Different pain-related pain response pattern, based on the avoidance-endurance
model, indicate the need for individual targeting of rehabilitation programs. |
List the releases of JASPAR database | JASPAR, JASPAR CORE, JASPAR FAM, JASPAR phyloFACTS, JASPAR 2008 update, JASPAR 2010, JASPAR 2014. | The analysis of regulatory regions in genome sequences is strongly based on the
detection of potential transcription factor binding sites. The preferred models
for representation of transcription factor binding specificity have been termed
position-specific scoring matrices. JASPAR is an open-access database of
annotated, high-quality, matrix-based transcription factor binding site profiles
for multicellular eukaryotes. The profiles were derived exclusively from sets of
nucleotide sequences experimentally demonstrated to bind transcription factors.
The database is complemented by a web interface for browsing, searching and
subset selection, an online sequence analysis utility and a suite of programming
tools for genome-wide and comparative genomic analysis of regulatory regions.
JASPAR is available at http://jaspar. cgb.ki.se. JASPAR is a popular open-access database for matrix models describing
DNA-binding preferences for transcription factors and other DNA patterns. With
its third major release, JASPAR has been expanded and equipped with additional
functions aimed at both casual and power users. The heart of the JASPAR
database-the JASPAR CORE sub-database-has increased by 12% in size, and three
new specialized sub-databases have been added. New functions include clustering
of matrix models by similarity, generation of random matrices by sampling from
selected sets of existing models and a language-independent Web Service
applications programming interface for matrix retrieval. JASPAR is available at
http://jaspar.genereg.net. JASPAR (http://jaspar.genereg.net) is the largest open-access database of
matrix-based nucleotide profiles describing the binding preference of
transcription factors from multiple species. The fifth major release greatly
expands the heart of JASPAR-the JASPAR CORE subcollection, which contains
curated, non-redundant profiles-with 135 new curated profiles (74 in
vertebrates, 8 in Drosophila melanogaster, 10 in Caenorhabditis elegans and 43
in Arabidopsis thaliana; a 30% increase in total) and 43 older updated profiles
(36 in vertebrates, 3 in D. melanogaster and 4 in A. thaliana; a 9% update in
total). The new and updated profiles are mainly derived from published chromatin
immunoprecipitation-seq experimental datasets. In addition, the web interface
has been enhanced with advanced capabilities in browsing, searching and
subsetting. Finally, the new JASPAR release is accompanied by a new BioPython
package, a new R tool package and a new R/Bioconductor data package to
facilitate access for both manual and automated methods. |
List symptoms of the IFAP syndrome. | The IFAP syndrome is a rare X-linked genetic disorder characterized by the triad of follicular ichthyosis, atrichia, and photophobia. | We report on a boy with short stature, mental retardation, seizures, follicular
ichthyosis, generalized alopecia, hypohydrosis, enamel dysplasia, photophobia,
congenital aganglionic megacolon, inguinal hernia, vertebral, renal and other
anomalies, and a normal chromosome constitution. The clinical findings include
all the features that dermotrichic and ichthyosis
follicularis-alopecia-photophobia (IFAP) syndrome have in common and in addition
those that characterize IFAP syndrome (photophobia, recurrent respiratory
infections, etc.), those that are present only in dermotrichic syndrome (nail
anomalies, hypohydrosis, megacolon, vertebral defects, etc.) and additional ones
(enamel dysplasia, renal anomalies, inguinal hernia, etc.). Two maternal uncles
were referred as being affected by alopecia and ichthyosis suggesting X-linked
recessive transmission. Various hypotheses concerning the relationship between
the 2 syndromes and the present case are discussed. We describe an 18-month-old male infant suffering from the ichthyosis
follicularis, atrichia, and photophobia (IFAP) syndrome and further delineate
the clinical phenotype. Severe retardation of growth and psychomotor
development, chill-like seizures, bronchial asthma, urticaria, a proneness to
skin infections and transient nail dystrophy observed in our patient are
non-obligatory manifestations of this disorder. Histological examination of the
atrichia revealed poorly developed, shortened hair follicles and a complete
absence of sebaceous glands. The sex ratio of published cases suggests an
X-linked recessive inheritance. The marked clinical variability of the IFAP
syndrome might be the expression of a contiguous gene defect. A diagnosis of IFAP (ichthyosis follicularis with atrichia and photophobia)
syndrome was established in a 1-year-old boy with congenital hairlessness,
generalized ichthyotic skin changes with follicular hyperkeratoses, and
photophobia. IFAP syndrome is considered to be an X-linked recessive trait. The
phenotype present in female carriers has so far not been delineated. A
2-year-old sister had atrophoderma and ichthyotic skin lesions arranged in a
linear pattern and a large noncicatrical bald patch on her scalp. Similarly, the
mother had linear lesions of scaling and atrophy as well as circumscribed
hairless areas involving the scalp, the axillary region, and the lower legs.
Sweat testing by means of iodine starch-reaction visualized hypohidrotic linear
lesions corresponding to the areas of hyperkeratosis and atrophy. In both mother
and daughter the lesions followed the lines of Blaschko, whereas the boy was
diffusely affected. Family history showed that the boy's maternal uncle who had
died at age 1 year was likewise affected with the same disorder. Moreover, the
maternal grandmother had reportedly bald patches on her scalp and very dry skin.
This is the first report to document linear skin lesions visualizing lyonization
in women heterozygous for IFAP syndrome. A boy with congenital atrichia, ichthyosis follicular, keratitis, cutaneous
infections and a huge inguinal hernia, but without deafness is reported. We
believe it represents a new case of a rare X-linked recessive syndrome known as
ichthyosis follicularis, alopecia, photophobia syndrome (IFAP). The differential
diagnosis from keratitis ichthyosis deafness is discussed. The cutaneous
infections seen in our case suggest the possibility of considering a genetic
link between these syndromes. The IFAP syndrome is characterized by the congenital onset of ichthyosis
follicularis, absence of hair, and photophobia. A limited number of patients
with the disorder have been described, and X-linked recessive inheritance has
been proposed. Two unrelated female patients with a complete IFAP syndrome are
reported. Both patients show a diffuse distribution of the disorder without
linear arrangement. Because the suggested X-linked recessive pattern of
inheritance is unlikely in these patients, a different way of transmission or,
alternatively, genetic heterogeneity of the disorder has to be considered. Two brothers with ichthyosis follicularis, noncicatricial universal alopecia,
photophobia, hyerkeratotic psoriasis-like lesions, nails dystrophy, inguineal
herniae, cryptorchidism, short stature, seizures, and psychomotor developmental
delay are described. These features correspond to the ichthyosis follicularis,
alopecia, photophobia (IFAP) syndrome. The youngest brother had in addition a
bilateral absence of 4th fingers and camptodactyly, features never reported in
patients with IFAP syndromes. PURPOSE: To report the ocular findings in two siblings with IFAP and their
mother and to review the natural course of the keratopathy of this disease.
METHODS: Clinical ophthalmological examination of all patients and fundus
photography of the carrier mother were performed.
RESULTS: Both affected male children had severe photophobia, total superficial
and deep corneal vascularization, and reduction of vision to counting
fingers.The mother had tortuous retinal vessels.
CONCLUSIONS: Males with IFAP have an inexorable progression of corneal
vascularization and loss of vision. Retinal vascular tortuosity may be another
clinical sign of carrier status in females. We describe a 3-year-old male patient with the ichthyosis follicularis, alopecia
and photophobia (IFAP) syndrome, who developed cutaneous and ocular involvement
in infancy. In addition, he had growth retardation and borderline intelligence;
no other systemic involvement was found on detailed investigation. A moderate
response to acitretin therapy (1 mg/kg) administered for 6 months was observed,
with improvement in cutaneous features and corneal erosions and no change in
alopecia or photophobia. Ichthyosis follicularis, alopecia and photophobia (IFAP) is a rare
genodermatosis. Most patients have been men without significant family history.
We present the largest kindred of IFAP reported to date in the medical
literature clearly demonstrating X-linked inheritance. The gene defect has
recently been mapped to Xp22.11-p22.13. Missense mutations of the gene, MBTPS2,
which codes for an intramembrane zinc metalloprotease essential for cholesterol
homeostasis and endoplasmic reticulum stress response, are associated with the
IFAP phenotype in this kindred. We describe the clinical features and discuss
the differential diagnosis of IFAP. Our proband has benefited from treatment
with acitretin. BACKGROUND: Ichthyosis follicularis, atrichia, and photophobia (IFAP) syndrome
is a rare congenital disorder. Missense mutations in the membrane-bound
transcription factor protease, site 2 (MBTPS2) gene have recently been
identified in patients with IFAP.
OBJECTIVE: To determine whether Chinese patients with IFAP have MBTPS2
mutations.
METHODS: We observed a large IFAP pedigree of 5 generations in a Chinese family
and performed MBTPS2 molecular analysis.
RESULTS: The male proband was severely affected. He presented with
hyperextensibility of the interphalangeal joints of the fingers in addition to
previously reported clinical manifestations. Clinically affected female patients
had hairless patches on the scalp, ichthyosiform skin changes, hypotrichosis,
hyperkeratosis, nail dystrophy, and brown scaly plaques, some of which were
arranged in a linear pattern following the lines of Blaschko. Molecular analysis
identified a novel missense mutation in exon 11 and confirmed cosegregation of
the missense mutation with the disease in this family.
LIMITATIONS: It is unclear whether hyperextensibility of the fingers was
nosologically related to IFAP syndrome or was a coincidental finding.
CONCLUSION: This report provides further evidence for the genetic basis of IFAP
syndrome and enlarges the phenotypic spectrum and number of MBTPS2 mutations. We
confirm that MBTPS2 mutations cause IFAP in patients of Chinese origin. Mutations in MBTPS2 have been reported to cause a broad phenotypic spectrum of
X-linked genodermatoses, including IFAP (ichthyosis follicularis; atrichia and
photophobia) syndrome (OMIM 308205) with or without BRESHECK (brain anomalies,
retardation of mentality and growth, ectodermal dysplasia, skeletal
malformations, Hirschsprung disease, ear deformity and deafness, eye hypoplasia,
cleft palate, cryptorchidism, and kidney dysplasia/hypoplasia) syndrome,
keratosis follicularis spinulosa decalvans (KFSD; OMIM 308800) and an X-linked
form of Olmsted syndrome. We report a recurrent intronic mutation in MBTPS2
(c.671-9T>G) in a Chinese patient with the typical triad of IFAP syndrome (i.e.
ichthyosis, atrichia and photophobia), along with pachyonychia, palmoplantar and
periorificial keratoderma, which were reminiscent of Olmsted syndrome.
Interestingly, this mutation was previously reported in two cases of IFAP
without keratoderma, which suggests clinical heterogeneicity of the same
mutation in MBTPS2. The concomitance of Olmsted syndrome-like features in this
patient with IFAP may challenge the existence of the X-linked form of Olmsted
syndrome as an independent condition. |
Which gene is required for the efficient function of clopidogrel? | The prodrug clopidogrel requires activation by cytochrome P-450 (CYP) enzymes for its antiplatelet effect. Variability in clopidogrel response might be influenced by polymorphisms in genes coding for drug metabolism enzymes (cytochrome P450 CYP2C19), transport proteins (P-glycoprotein) and/or target proteins for the drug (adenosine diphosphate-receptor P2Y12). The CYP2C19 loss-of-function alleles had a gene dose effect on the pharmacodynamics and composite ischemic events of clopidogrel in our study population. Neither the ABCB1 nor the PON1 genotype significantly influenced the antiplatelet effect and clinical outcomes of clopidogrel in these patients | BACKGROUND AND PURPOSE: There is considerable variability in the antiplatelet
effects of the thienopyridine agent "clopidogrel." We tested for an association
of gene sequence variations in P2Y12 and occurrence of neurological adverse
events in patients with symptomatic peripheral artery disease (PAD) during
clopidogrel treatment.
METHODS: We studied 137 patients undergoing antiplatelet therapy with
clopidogrel and 336 patients with aspirin for the occurrence of neurological
events (ischemic stroke and/or carotid revascularization). Prevalence of 2
previously described exonic polymorphisms of the P2Y12 gene, 34C>T and 52G>T,
was determined by polymerase chain reaction.
RESULTS: Genotype frequencies for mutated, heterozygous, and wild-type alleles
for the 34C>T and the 52G>T polymorphisms were 9% (n=40), 44% (n=210), and 47%
(n=223), and 4% (n=17), 27% (n=127), and 70% (n=329), respectively. During the
median follow-up of 21 months, neurological events occurred in 8% of patients.
In patients with aspirin therapy, neither polymorphism was associated with
neurological events. However, in clopidogrel patients, carriers of at least one
34T allele had a 4.02-fold increased adjusted risk for neurological events
compared with carriers of only 34C alleles (95% confidence interval, 1.08 to
14.9). Neither polymorphism was associated with all-cause mortality.
CONCLUSIONS: In PAD patients, clopidogrel response variability exists, which may
result in increased risk for cerebrovascular events. Sequence alterations of the
target receptor gene represent one possible mechanism for clopidogrel failure.
Whether identification of the 34C>T polymorphism as a contributor to this
process could serve as risk stratification tool, an indicator for higher
clopidogrel doses, or the use of alternate agents warrants further
investigation. OBJECTIVES: This study assessed the effect of pharmacogenetics on the
antiplatelet effect of clopidogrel.
BACKGROUND: Variability in clopidogrel response might be influenced by
polymorphisms in genes coding for drug metabolism enzymes (cytochrome P450 [CYP]
family), transport proteins (P-glycoprotein) and/or target proteins for the drug
(adenosine diphosphate-receptor P2Y12).
METHODS: Sixty patients undergoing elective percutaneous coronary intervention
in the randomized PRINC (Plavix Response in Coronary Intervention) trial had
platelet function measured using the VerifyNow P2Y12 analyzer after a 600-mg or
split 1,200-mg loading dose and after a 75- or 150-mg daily maintece dosage.
Polymerase chain reaction-based genotyping evaluated polymorphisms in the
CYP2C19, CYP2C9, CYP3A4, CYP3A5, ABCB1, P2Y12, and CES genes.
RESULTS: CYP2C19*1*1 carriers had greater platelet inhibition 2 h after a 600-mg
dose (median: 23%, range: 0% to 66%), compared with platelet inhibition in
CYP2C19*2 or *4 carriers (10%, 0% to 56%, p = 0.029) and CYP2C19*17 carriers
(9%, 0% to 98%, p = 0.026). CYP2C19*2 or *4 carriers had greater platelet
inhibition with the higher loading dose than with the lower dose at 4 h (37%, 8%
to 87% vs. 14%, 0% to 22%, p = 0.002) and responded better with the higher
maintece dose regimen (51%, 15% to 86% vs. 14%, 0% to 67%, p = 0.042).
CONCLUSIONS: Carriers of the CYP2C19*2 and *4 alleles showed reduced platelet
inhibition after a clopidogrel 600-mg loading dose but responded to higher
loading and maintece dose regimens. Genotyping for the relevant gene
polymorphisms may help to individualize and optimize clopidogrel treatment.
(Australia New Zealand Clinical Trials Registry; ACTRN12606000129583). AIM: To determine the effect of various SNPs on post-clopidogrel platelet
reactivity and clinical outcome.
MATERIALS & METHODS: Cytochrome 2C19 (CYP2C19) loss-of-function (LOF; *2, *3)
and gain-of-function (GOF; *17) allelic variants, together with ABCB1 (3435 C→T
and 2677 G→T/A) and paraoxonase-1 (PON-1; 192 Q→R) SNPs were analyzed in 189
patients after elective stent implantation who participated in a randomized,
placebo-controlled trial (NCT00638326). Platelet reactivity was determined with
light transmission aggregometry and vasodilator stimulated phosphoprotein
phosphorylation (VASP-PRI) 12-24 h after 600 mg clopidogrel. High on-treatment
platelet reactivity (HTPR) was defined according to the consensus definition
(ADP 5 µM >46%; VASP-PRI>50%).
RESULTS: In the case of CYP2C19 genotypes, a gene-dose effect was observed in
ADP reactivity with the lowest values in GOF homozygotes and the highest degree
in patients carrying two LOF alleles. The odds for HTPR also increased with the
number of LOF alleles. There were no significant differences in platelet
reactivity according to PON-1 or ABCB1 genotypes. In multivariate analysis, the
presence of a CYP2C19 LOF allele turned out to be the independent determit of
HTPR. Although the study was not powered to clinical outcome (not LOF
heterozygotes), only patients with two LOF alleles had a significantly higher
risk for cardiovascular death, myocardial infarction or unplanned target vessel
revascularization at 1 year compared with non-LOF carriers.
CONCLUSION: Genetic variants in CYP2C19 have a gene-dose effect on
post-clopidogrel platelet reactivity, with homozygote LOF carriers having the
highest risk for HTPR and for adverse ischemic events. Neither ABCB1 nor PON-1
genotypes significantly influenced platelet reactivity or outcome. PURPOSE: Chinese people are more frequent carriers of cytochrome P450 2C19
(CYP2C19) loss-of-function alleles than Caucasians. The effect of the
ATP-binding cassette, sub-family B, member 1 (ABCB1), and paraoxonase 1 (PON1)
variants on platelet reactivity and clinical outcomes of clopidogrel treatment
has not yet been reported in Chinese patients after percutaneous coronary
intervention. The aim of this study was to investigate the effect of the
CYP2C19, ABCB1, and PON1 variants on clopidogrel pharmacodynamics and clinical
outcomes in these patients.
METHODS: Six hundred and seventy patients after percutaneous coronary
intervention were enrolled in a single-center registry. The antiplatelet effect
of clopidogrel was assessed by thromboelastography, and the CYP2C19, ABCB1, and
PON1 genotypes were detected by the ligase detection reaction. Primary clinical
endpoints included cardiovascular death, nonfatal myocardial infarction, target
vessel revascularization, and stent thrombosis. The secondary clinical endpoints
were thrombolysis in myocardial infarction bleeding. The follow-up period was 12
months.
RESULTS: The frequency of the CYP2C19 loss-of-function alleles was relatively
high (57.3 %). The risk of a low response to clopidogrel and composite ischemic
events increased with the number of CYP2C19 loss-of-function alleles. However,
there were not significant differences in clopidogrel pharmacodynamics and
clinical outcomes across the ABCB1 and PON1 genotype groups; bleeding was not
significantly different across the CYP2C19, ABCB1, and PON1 genotype groups.
CONCLUSIONS: The CYP2C19 loss-of-function alleles had a gene dose effect on the
pharmacodynamics and composite ischemic events of clopidogrel in our study
population. Neither the ABCB1 nor the PON1 genotype significantly influenced the
antiplatelet effect and clinical outcomes of clopidogrel in these patients. BACKGROUND: The CYP2C19 G681A single polymorphism has been proven to affect
clopidogrel responsiveness. However, the effect of coexisting polymorphisms of
other genes has not yet been reported in the Chinese population. This study
investigated the effect of coexisting polymorphisms of CYP2C19 and P2Y12 on
clopidogrel responsiveness and adverse clinical events in Chinese patients.
METHODS: In 577 Han Chinese patients undergoing stent placement because of acute
coronary syndrome had platelet reactivity assessed by thromboelastography, and
the CYP2C19 G681A and P2Y12 C34T polymorphisms were detected by the ligase
detection reaction. Primary clinical endpoints included cardiovascular death,
nonfatal myocardial infarction, target vessel revascularization, and stent
thrombosis. The secondary clinical endpoints were thrombolysis in myocardial
infarction bleeding. The follow-up period was 12 months.
RESULTS: Genotyping revealed 194 carriers of the wild type GG genotype of
CYP2C19 and the wild type CC genotype of P2Y12 (group 1), 102 carriers of the
wild type GG genotype of CYP2C19 and the mutational T allele of P2Y12 (group 2),
163 carriers of the mutational A allele of CYP2C19 and the wild type CC genotype
of P2Y12 (group 3), and 118 carriers of the mutational A allele of CYP2C19 and
the mutational T allele of P2Y12 (group 4). Group 4 had the lowest
ADP-inhibition (49.74 ± 32.61) and the highest prevalence of clopidogrel low
response (29.7%) of the four groups. The rate of the composite of primary
clinical endpoints increased more in group 4 (8.5%) than in the other three
groups; the rate of composite primary endpoints in group 2 (2.9%) and group 3
(3.7%) were not significantly different than that of group 1 (1.5%).
CONCLUSION: Coexisting polymorphisms of different genes affected clopidogrel
responsiveness and clinical outcome more than single polymorphism in Chinese
patients with acute coronary syndrome undergoing percutaneous coronary
intervention. |
Is valproic acid effective for glioblastoma treatment? | Yes, valproic acid prolong survival of glioblastoma patients. Valproic acid is an antiepileptic agent with histone deacetylase inhibitor activity shown to sensitize glioblastoma cells to radiation in preclinical models. | PURPOSE: Valproic acid (VA) is an antiepileptic drug (AED) and histone
deacetylase (HDAC) inhibitor taken by patients with glioblastoma (GB) to manage
seizures, and it can modulate the biologic effects of radiation therapy (RT). We
investigated whether VA use during RT for GB was associated with overall
survival (OS).
METHODS AND MATERIALS: Medical records of 544 adults with GB were
retrospectively reviewed. Analyses were performed to determine the association
of Radiation Therapy Oncology Group recursive partitioning analysis (RTOG RPA)
class, seizure history, and concurrent temozolomide (TMZ) and AED use during RT
with OS.
RESULTS: Seizures before the end of RT were noted in 217 (40%) patients, and 403
(74%) were taking an AED during RT; 29 (7%) were taking VA. Median OS in
patients taking VA was 16.9 months (vs 13.6 months taking another AED, P=.16).
Among patients taking an AED during RT, OS was associated with VA (P=.047;
hazard ratio [HR], 0.67; 95% confidence interval [CI], 0.27-1.07), and RTOG RPA
class (P<.0001; HR, 1.49; 95% CI, 1.37-1.61). Of the 5 most common AEDs, only VA
was associated with OS. Median OS of patients receiving VA and TMZ during RT was
23.9 months (vs 15.2 months for patients taking another AED, P=.26). When the
analysis was restricted to patients who received concurrent TMZ, VA use was
marginally associated with OS (P=.057; HR, 0.54; 95% CI, -0.09 to 1.17),
independently of RTOG RPA class and seizure history.
CONCLUSIONS: VA use during RT for GB was associated with improved OS,
independently of RTOG RPA, seizure history, and concurrent TMZ use. Further
studies of treatment that combines HDAC inhibitors and RT are warranted. BACKGROUND: To examine the efficacy of valproic acid (VPA) given either with or
without levetiracetam (LEV) on seizure control and on survival in patients with
glioblastoma multiforme (GBM) treated with chemoradiation.
METHODS: A retrospective analysis was performed on 291 patients with GBM. The
efficacies of VPA and LEV alone and as polytherapy were analyzed in 181 (62%)
patients with seizures with a minimum follow-up of 6 months. Cox-regression
survival analysis was performed on 165 patients receiving chemoradiation with
temozolomide of whom 108 receiving this in combination with VPA for at least 3
months.
RESULTS: Monotherapy with either VPA or LEV was instituted in 137/143 (95.8%)
and in 59/86 (68.6%) on VPA/LEV polytherapy as the next regimen. Initial freedom
from seizure was achieved in 41/100 (41%) on VPA, in 16/37 (43.3%) on LEV, and
in 89/116 (76.7%) on subsequent VPA/LEV polytherapy. At the end of follow-up,
seizure freedom was achieved in 77.8% (28/36) on VPA alone, in 25/36 (69.5%) on
LEV alone, and in 38/63 (60.3%) on VPA/LEV polytherapy with ongoing seizures on
monotherapy. Patients using VPA in combination with temozolomide showed a longer
median survival of 69 weeks (95% confidence interval [CI]: 61.7-67.3) compared
with 61 weeks (95% CI: 52.5-69.5) in the group without VPA (hazard ratio, 0.63;
95% CI: 0.43-0.92; P = .016), adjusting for age, extent of resection, and
O(6)-DNA methylguanine-methyltransferase promoter methylation status.
CONCLUSIONS: Polytherapy with VPA and LEV more strongly contributes to seizure
control than does either as monotherapy. Use of VPA together with chemoradiation
with temozolomide results in a 2-months' longer survival of patients with GBM. PURPOSE: Glioblastoma multiforme (GBM) is the most lethal type of primary brain
tumor, and patients that undergo the maximum tumor resection that is safely
possible and standard radiochemotherapy only achieve a median survival time of
14.6 months. Several clinical studies have reported that valproic acid could
prolong survival of GBM patients. However, the results of these studies are
inconsistent. We examined relevant studies and conducted a meta-analysis to
assess the effects of VPA on survival times and recurrence.
METHODS: A bibliographic search was performed in the EMBASE, MEDLINE,
ClinicalTrials.gov and Cochrane Central Register of the Controlled Trials
databases to identify potentially relevant articles or conference abstracts that
investigated the effects of VPA on the outcome of glioma patients. Five
observational studies were included.
RESULTS: Pooled estimates of the hazard ratio (HR) and 95% confidence intervals
(CI) were calculated. Our meta-analysis confirmed the benefit of using VPA (HR,
0.56; 95% CI, 0.44-0.71). Sub-group analysis shows that patients treated with
VPA had a hazard ratio of 0.74 with a 95% confidence interval of 0.59-0.94 vs.
patients treated by other-AEDs and a hazard ratio of 0.66 with a 95% confidence
interval of 0.52-0.84 vs. patients treated by administration of non-AEDs. No
heterogeneity was observed in the subset analysis.
CONCLUSION: The results of our study suggest that glioblastoma patients may
experience prolonged survival due to VPA administration. Sub-analysis confirmed
the benefit of VPA use compared to a non-AEDs group and an other-AEDs group.
Further RCTs of this subject should be performed. |
Which transcription factor is considered as a master regulator of lysosomal genes? | Transcription factor EB (TFEB) is a master regulator of lysosomal biogenesis and autophagy, driving lysosome adaptation to environmental cues, such as starvation, and therefore targeting of TFEB may provide a novel therapeutic strategy for modulating lysosomal function in human disease. | Mammalian target of rapamycin (mTOR) complex 1 (mTORC1) is an important, highly
conserved, regulator of cell growth. Ancient among the signals that regulate
mTORC1 are nutrients. Amino acids direct mTORC1 to the surface of the late
endosome/lysosome, where mTORC1 becomes receptive to other inputs. However, the
interplay between endosomes and mTORC1 is poorly understood. Here, we report the
discovery of a network that links mTORC1 to a critical component of the late
endosome/lysosome, the V-ATPase. In an unbiased screen, we found that mTORC1
regulated the expression of, among other lysosomal genes, the V-ATPases. mTORC1
regulates V-ATPase expression both in cells and in mice. V-ATPase regulation by
mTORC1 involves a transcription factor translocated in renal cancer, TFEB. TFEB
is required for the expression of a large subset of mTORC1 responsive genes.
mTORC1 coordinately regulates TFEB phosphorylation and nuclear localization and
in a manner dependent on both TFEB and V-ATPases, mTORC1 promotes endocytosis.
These data uncover a regulatory network linking an oncogenic transcription
factor that is a master regulator of lysosomal biogenesis, TFEB, to mTORC1 and
endocytosis. The lysosome plays a key role in cellular homeostasis by controlling both
cellular clearance and energy production to respond to environmental cues.
However, the mechanisms mediating lysosomal adaptation are largely unknown.
Here, we show that the Transcription Factor EB (TFEB), a master regulator of
lysosomal biogenesis, colocalizes with master growth regulator mTOR complex 1
(mTORC1) on the lysosomal membrane. When nutrients are present, phosphorylation
of TFEB by mTORC1 inhibits TFEB activity. Conversely, pharmacological inhibition
of mTORC1, as well as starvation and lysosomal disruption, activates TFEB by
promoting its nuclear translocation. In addition, the transcriptional response
of lysosomal and autophagic genes to either lysosomal dysfunction or
pharmacological inhibition of mTORC1 is suppressed in TFEB-/- cells.
Interestingly, the Rag GTPase complex, which senses lysosomal amino acids and
activates mTORC1, is both necessary and sufficient to regulate starvation- and
stress-induced nuclear translocation of TFEB. These data indicate that the
lysosome senses its content and regulates its own biogenesis by a
lysosome-to-nucleus signalling mechanism that involves TFEB and mTOR. Loss-of-function diseases are often caused by destabilizing mutations that lead
to protein misfolding and degradation. Modulating the innate protein homeostasis
(proteostasis) capacity may lead to rescue of native folding of the mutated
variants, thereby ameliorating the disease phenotype. In lysosomal storage
disorders (LSDs), a number of highly prevalent alleles have missense mutations
that do not impair the enzyme's catalytic activity but destabilize its native
structure, resulting in the degradation of the misfolded protein. Enhancing the
cellular folding capacity enables rescuing the native, biologically functional
structure of these unstable mutated enzymes. However, proteostasis modulators
specific for the lysosomal system are currently unknown. Here, we investigate
the role of the transcription factor EB (TFEB), a master regulator of lysosomal
biogenesis and function, in modulating lysosomal proteostasis in LSDs. We show
that TFEB activation results in enhanced folding, trafficking and lysosomal
activity of a severely destabilized glucocerebrosidase (GC) variant associated
with the development of Gaucher disease (GD), the most common LSD. TFEB
specifically induces the expression of GC and of key genes involved in folding
and lysosomal trafficking, thereby enhancing both the pool of mutated enzyme and
its processing through the secretory pathway. TFEB activation also rescues the
activity of a β-hexosaminidase mutant associated with the development of another
LSD, Tay-Sachs disease, thus suggesting general applicability of TFEB-mediated
proteostasis modulation to rescue destabilizing mutations in LSDs. In summary,
our findings identify TFEB as a specific regulator of lysosomal proteostasis and
suggest that TFEB may be used as a therapeutic target to rescue enzyme
homeostasis in LSDs. The mTORC1 complex supports cell growth and proliferation in response to energy
levels, growth factors, and nutrients. The Rag guanosine triphosphatases
(GTPases) activate mTORC1 in response to amino acids by promoting its
redistribution to lysosomes. In this paper, we identify a novel role for Rags in
controlling activation of transcription factor EB (TFEB), a master regulator of
autophagic and lysosomal gene expression. Interaction of TFEB with active Rag
heterodimers promoted recruitment of TFEB to lysosomes, leading to
mTORC1-dependent phosphorylation and inhibition of TFEB. The interaction of TFEB
with Rags required the first 30 residues of TFEB and the switch regions of the
Rags G domain. Depletion or inactivation of Rags prevented recruitment of TFEB
to lysosomes, whereas expression of active Rags induced association of TFEB with
lysosomal membranes. Finally, Rag GTPases bound and regulated activation of
microphthalmia-associated transcription factor, suggesting a broader role for
Rags in the control of gene expression. Our work provides new insight into the
molecular mechanisms that link nutrient availability and TFEB localization and
activation. When the levels of intracellular amino acids are high, RRAG GTPases recruit
MTORC1 to lysosomes and promote its activation. We found that RRAGs also recruit
specific MTORC1 substrates to the lysosomal surface, thus facilitating
MTORC1-mediated phosphorylation and regulation. In particular, active RRAGs
interact with the transcription factor EB (TFEB), the master regulator of a gene
network that promotes lysosomal biogenesis and autophagy. Redistribution to
lysosomes is critical for MTORC1-dependent inactivation of TFEB under
nutrient-rich conditions. Therefore, RRAGs play a critical role coordinating
nutrient availability and cellular clearance. The lysosomal-autophagic pathway is activated by starvation and plays an
important role in both cellular clearance and lipid catabolism. However, the
transcriptional regulation of this pathway in response to metabolic cues is
uncharacterized. Here we show that the transcription factor EB (TFEB), a master
regulator of lysosomal biogenesis and autophagy, is induced by starvation
through an autoregulatory feedback loop and exerts a global transcriptional
control on lipid catabolism via Ppargc1α and Ppar1α. Thus, during starvation a
transcriptional mechanism links the autophagic pathway to cellular energy
metabolism. The conservation of this mechanism in Caenorhabditis elegans
suggests a fundamental role for TFEB in the evolution of the adaptive response
to food deprivation. Viral delivery of TFEB to the liver prevented weight gain
and metabolic syndrome in both diet-induced and genetic mouse models of obesity,
suggesting a new therapeutic strategy for disorders of lipid metabolism. For a long time, lysosomes were considered merely to be cellular 'incinerators'
involved in the degradation and recycling of cellular waste. However, now there
is compelling evidence indicating that lysosomes have a much broader function
and that they are involved in fundamental processes such as secretion, plasma
membrane repair, signalling and energy metabolism. Furthermore, the essential
role of lysosomes in autophagic pathways puts these organelles at the crossroads
of several cellular processes, with significant implications for health and
disease. The identification of a master regulator, transcription factor EB
(TFEB), that regulates lysosomal biogenesis and autophagy has revealed how the
lysosome adapts to environmental cues, such as starvation, and targeting TFEB
may provide a novel therapeutic strategy for modulating lysosomal function in
human disease. OBJECTIVE: Recent reports of a proatherogenic phenotype in mice with
macrophage-specific autophagy deficiency have renewed interest in the role of
the autophagy-lysosomal system in atherosclerosis. Lysosomes have the unique
ability to process both exogenous material, including lipids and
autophagy-derived cargo such as dysfunctional proteins/organelles. We aimed to
understand the effects of an atherogenic lipid environment on macrophage
lysosomes and to evaluate novel ways to modulate this system.
APPROACH AND RESULTS: Using a variety of complementary techniques, we show that
oxidized low-density lipoproteins and cholesterol crystals, commonly encountered
lipid species in atherosclerosis, lead to profound lysosomal dysfunction in
cultured macrophages. Disruptions in lysosomal pH, proteolytic capacity,
membrane integrity, and morphology are readily seen. Using flow cytometry, we
find that macrophages isolated from atherosclerotic plaques also display
features of lysosome dysfunction. We then investigated whether enhancing
lysosomal function can be beneficial. Transcription factor EB (TFEB) is the only
known transcription factor that is a master regulator of lysosomal biogenesis
although its role in macrophages has not been studied. Lysosomal stress induced
by chloroquine or atherogenic lipids leads to TFEB nuclear translocation and
activation of lysosomal and autophagy genes. TFEB overexpression in macrophages
further augments this prodegradative response and rescues several deleterious
effects seen with atherogenic lipid loading as evidenced by blunted lysosomal
dysfunction, reduced secretion of the proinflammatory cytokine interleukin-1β,
enhanced cholesterol efflux, and decreased polyubiquitinated protein
aggregation.
CONCLUSIONS: Taken together, these data demonstrate that lysosomal function is
markedly impaired in atherosclerosis and suggest that induction of a lysosomal
biogenesis program in macrophages has antiatherogenic effects. Cerium oxide oparticles (oceria) are widely used in a variety of
industrial applications including UV filters and catalysts. The expanding
commercial scale production and use of ceria oparticles have inevitably
increased the risk of release of oceria into the environment as well as the
risk of human exposure. The use of oceria in biomedical applications is also
being currently investigated because of its recently characterized antioxidative
properties. In this study, we investigated the impact of ceria oparticles on
the lysosome-autophagy system, the main catabolic pathway that is activated in
mammalian cells upon internalization of exogenous material. We tested a battery
of ceria oparticles functionalized with different types of biocompatible
coatings (N-acetylglucosamine, polyethylene glycol and polyvinylpyrrolidone)
expected to have minimal effect on lysosomal integrity and function. We found
that ceria oparticles promote activation of the transcription factor EB, a
master regulator of lysosomal function and autophagy, and induce upregulation of
genes of the lysosome-autophagy system. We further show that the array of
differently functionalized ceria oparticles tested in this study enhance
autophagic clearance of proteolipid aggregates that accumulate as a result of
inefficient function of the lysosome-autophagy system. This study provides a
mechanistic understanding of the interaction of ceria oparticles with the
lysosome-autophagy system and demonstrates that ceria oparticles are
activators of autophagy and promote clearance of autophagic cargo. These results
provide insights for the use of oceria in biomedical applications, including
drug delivery. These findings will also inform the design of engineered
oparticles with safe and precisely controlled impact on the environment and
the design of otherapeutics for the treatment of diseases with defective
autophagic function and accumulation of lysosomal storage material. Canonical Wnt signaling plays an important role in development and disease,
regulating transcription of target genes and stabilizing many proteins
phosphorylated by glycogen synthase kinase 3 (GSK3). We observed that the MiT
family of transcription factors, which includes the melanoma oncogene MITF
(micropthalmia-associated transcription factor) and the lysosomal master
regulator TFEB, had the highest phylogenetic conservation of three consecutive
putative GSK3 phosphorylation sites in animal proteomes. This finding prompted
us to examine the relationship between MITF, endolysosomal biogenesis, and Wnt
signaling. Here we report that MITF expression levels correlated with the
expression of a large subset of lysosomal genes in melanoma cell lines. MITF
expression in the tetracycline-inducible C32 melanoma model caused a marked
increase in vesicular structures, and increased expression of late endosomal
proteins, such as Rab7, LAMP1, and CD63. These late endosomes were not
functional lysosomes as they were less active in proteolysis, yet were able to
concentrate Axin1, phospho-LRP6, phospho-β-catenin, and GSK3 in the presence of
Wnt ligands. This relocalization significantly enhanced Wnt signaling by
increasing the number of multivesicular bodies into which the Wnt
signalosome/destruction complex becomes localized upon Wnt signaling. We also
show that the MITF protein was stabilized by Wnt signaling, through the novel
C-terminal GSK3 phosphorylations identified here. MITF stabilization caused an
increase in multivesicular body biosynthesis, which in turn increased Wnt
signaling, generating a positive-feedback loop that may function during the
proliferative stages of melanoma. The results underscore the importance of
misregulated endolysosomal biogenesis in Wnt signaling and cancer. Lysosomes are ubiquitous membrane-enclosed organelles filled with an acidic
interior and are central to the autophagic, endocytic, or phagocytic pathway. In
contrast to its classical function as the waste management machinery, lysosomes
are now considered to be an integral part of various cellular signaling
processes. The diverse functionality of this single organelle requires a very
complex and coordinated regulation of its activity with transcription factor EB
(TFEB), a master regulator of lysosomal biogenesis, at its core. However,
mechanisms by which TFEB is regulated are poorly understood. This study
demonstrates that gemfibrozil, an agonist of peroxisome proliferator-activated
receptor (PPAR) α, alone and in conjunction with all-trans-retinoic acid is
capable of enhancing TFEB in brain cells. We also observed that PPARα, but not
PPARβ and PPARγ, is involved in gemfibrozil-mediated up-regulation of TFEB.
Reporter assay and chromatin immunoprecipitation studies confirmed the
recruitment of retinoid X receptor α, PPARα, and PGC1α on the PPAR-binding site
on the Tfeb promoter as well. Subsequently, the drug-mediated induction of TFEB
caused an increase in lysosomal protein and the lysosomal abundance in cell.
Collectively, this study reinforces the link between lysosomal biogenesis and
lipid metabolism with TFEB at the crossroads. Furthermore, gemfibrozil may be of
therapeutic value in the treatment of lysosomal storage disorders in which
autophagy-lysosome pathway plays an important role. |
Which antibiotics target peptidoglycan biosynthesis? | Under some conditions, both ramoplanin and vancomycin probes produce helicoid staining patterns along the cylindrical walls of B. subtilis cells. This work has implications for the design of ramoplanin derivatives and may influence how other proposed substrate binding antibiotics are studied. This was confirmed by in vitro studies involving a wall-membrane particulate fraction from Gaffkya homari in which peptidoglycan synthesis from UDP-MurNAc-tetrapeptide was inhibited by ramoplanin but not by vancomycin. New results support a two-state model for septal and peripheral PG synthesis at mid-cell, involvement of essential cell division proteins in PG remodeling, and mid-cell localization of proteins that organize PG biosynthesis and that form the protein translocation apparatus. | Mersacidin is an antibiotic peptide produced by Bacillus sp. strain HIL
Y-85,54728 that belongs to the group of lantibiotics. Its activity in vivo
against methicillin-resistant Staphylococcus aureus strains compares with that
of the glycopeptide antibiotic vancomycin (S. Chatterjee, D. K. Chatterjee, R.
H. Jani, J. Blumbach, B. N. Ganguli, N. Klesel, M. Limbert, and G. Seibert, J.
Antibiot. 45:839-845, 1992). Incubation of Staphylococcus simulans 22 with
mersacidin resulted in the cessation of growth and slow lysis. Biosyntheses of
DNA, RNA, and protein were not affected, whereas incorporation of glucose and
D-alanine was inhibited and a regular reduction in the level of cell wall
thickness was observed. Thus, unlike type A lantibiotics, mersacidin does not
form pores in the cytoplasmic membrane but rather inhibits cell wall
biosynthesis. Comparison with tunicamycin-treated cells indicated that
peptidoglycan rather than teichoic acid metabolism is primarily affected.
Mersacidin caused the excretion of a putative cell wall precursor into the
culture supernatant. The formation of polymeric peptidoglycan was effectively
inhibited in an in vitro assay, probably on the level of transglycosylation. In
contrast to vancomycin, the activity of mersacidin was not antagonized by the
tripeptide diacetyl-L-Lys-D-Ala-D-Ala, indicating that on the molecular level
its mode of action differs from those of glycopeptide antibiotics. These data
together with electron microscopy suggest that mersacidin acts on a novel
target, which opens new perspectives for the treatment of methicillin-resistant
S. aureus. The lantibiotic mersacidin has been previously reported to interfere with
bacterial peptidoglycan biosynthesis, [Brötz, H., Bierbaum, G., Markus, A.,
Molitor, E. & Sahl, H.-G. (1995) Antimicrob. Agents Chemother. 39, 714-719].
Here, we focus on the target reaction and describe a mersacidin-induced
accumulation of UDP-N-acetylmuramoyl-pentapeptide, indicating that inhibition of
peptidoglycan synthesis occurs after the formation of cytoplasmic precursors. In
vitro studies involving a wall-membrane particulate fraction of Bacillus
megaterium KM demonstrated that mersacidin did not prevent the synthesis of
lipid II [undecaprenyl-diphosphoryl-N-acetylmuramoyl-(pentapeptide)-N-ac ety
lglucosamine] but specifically the subsequent conversion of this intermediate
into polymeric nascent glycan strands by transglycosylation. Comparison with
other inhibitors of transglycosylation shows that the effective concentration of
mersacidin in vitro is in the range of that of the glycopeptide antibiotic
vancomycin but 2-3 orders of magnitude higher than that of the competitive
enzyme inhibitor moenomycin. The analogy to the glycopeptides may hint at an
interaction of mersacidin with the peptidoglycan precursor rather than with the
enzyme. Unlike vancomycin however, mersacidin inhibits peptidoglycan formation
from UDP-N-acetylmuramoyl-tripeptide and is active against Enterococcus faecium
expressing the vanA resistance gene cluster. This indicates that the molecular
target site of mersacidin differs from that of vancomycin and that no
cross-resistance exists between the two antibiotics. Vancomycin binds to bacterial cell-wall intermediates to achieve its antibiotic
effect. Infections of vancomycin-resistant enterococci are, however, becoming an
increasing problem; the bacteria are resistant because they synthesize different
cell-wall intermediates. The enzymes involved in cell-wall biosynthesis,
therefore, are potential targets for combating this resistance. Recent
biochemical and crystallographic results are providing mechanistic and
structural details about some of these targets. Mycobacterium smegmatis is a fast-growing nonpathogenic species particularly
useful in studying basic cellular processes of relevance to pathogenic
mycobacteria. This study focused on the D-alanine racemase gene (alrA), which is
involved in the synthesis of D-alanine, a basic component of peptidoglycan that
forms the backbone of the cell wall. M. smegmatis alrA null mutants were
generated by homologous recombination using a kanamycin resistance marker for
insertional inactivation. Mutants were selected on Middlebrook medium
supplemented with 50 mM D-alanine and 20 microg of kanamycin per ml. These
mutants were also able to grow in standard and minimal media without D-alanine,
giving rise to colonies with a drier appearance and more-raised borders than the
wild-type strain. The viability of the mutants and independence of D-alanine for
growth indicate that inactivation of alrA does not impose an auxotrophic
requirement for D-alanine, suggesting the existence of a new pathway of
D-alanine biosynthesis in M. smegmatis. Biochemical analysis demonstrated the
absence of any detectable D-alanine racemase activity in the mutant strains. In
addition, the alrA mutants displayed hypersusceptibility to the
antimycobacterial agent D-cycloserine. The MIC of D-cycloserine for the mutant
strain was 2.56 microg/ml, 30-fold less than that for the wild-type strain.
Furthermore, this hypersusceptibility was confirmed by the bactericidal action
of D-cycloserine on broth cultures. The kinetic of killing for the mutant strain
followed the same pattern as that for the wild-type strain, but at a
30-fold-lower drug concentration. This effect does not involve a change in the
permeability of the cell wall by this drug and is consistent with the
identification of D-alanine racemase as a target of D-cycloserine. This outcome
is of importance for the design of novel antituberculosis drugs targeting
peptidoglycan biosynthesis in mycobacteria. The muraymycins, a family of nucleoside-lipopeptide antibiotics, were purified
from the extract of Streptomyces sp. LL-AA896. The antibiotics were purified by
chromatographic methods and characterized by NMR spectroscopy, degradation
studies, and mass spectrometry. The structures of 19 compounds were established.
The muraymycins constitute a new antibiotic family whose core structure contains
a glycosylated uronic acid derivative joined by an aminopropane group to a
hexahydro-2-imino-4-pyrimidylglycyl residue (epicapreomycidine) containing
dipeptide that is further extended by a urea-valine moiety. Members of this
family show broad-spectrum in vitro antimicrobial activity against a variety of
clinical isolates (MIC 2 to >64 mug/mL). The muraymycins inhibited peptidoglycan
biosynthesis. The fatty acid substituent and the presence or absence of the
amino sugar play important roles in biological activity. One of the most active
compounds, muraymycin A1, demonstrated protection in vivo against Staphylococcus
aureus infection in mice (ED50 1.1 mg/kg). The peptidoglycan (PG) layers surrounding bacterial cells play an important role
in determining cell shape. The machinery controlling when and where new PG is
made is not understood, but is proposed to involve interactions between
bacterial actin homologs such as Mbl, which forms helical cables within cells,
and extracellular multiprotein complexes that include penicillin-binding
proteins. It has been suggested that labeled antibiotics that bind to PG
precursors may be useful for imaging PG to help determine the genes that control
the biosynthesis of this polymer. Here, we compare the staining patterns
observed in Bacillus subtilis using fluorescent derivatives of two PG-binding
antibiotics, vancomycin and ramoplanin. The staining patterns for both probes
exhibit a strong dependence on probe concentration, suggesting
antibiotic-induced perturbations in PG synthesis. Ramoplanin probes may be
better imaging agents than vancomycin probes because they yield clear staining
patterns at concentrations well below their minimum inhibitory concentrations.
Under some conditions, both ramoplanin and vancomycin probes produce helicoid
staining patterns along the cylindrical walls of B. subtilis cells. This
sidewall staining is observed in the absence of the cytoskeletal protein Mbl.
Although Mbl plays an important role in cell shape determination, our data
indicate that other proteins control the spatial localization of the
biosynthetic complexes responsible for new PG synthesis along the walls of B.
subtilis cells. Specific drug-sensing systems that coordinate appropriate genetic responses
assure the survival of microorganisms in the presence of antibiotics. We report
on the development and application of a microtiter plate-based bioassay for the
identification of antibiotics interfering with the lipid II cycle essential for
peptidoglycan biosynthesis. A Bacillus subtilis reporter strain sensing
specifically lipid II - interfering cell wall biosynthesis stress (T. Mascher,
S.L. Zimmer, T.-A. Smith and J. Helmann, Antibiotic-inducible promoter regulated
by the cell envelope stress-sensing two-component system LiaRS of Bacillus
subtilis; Antimicrob. Agents Chemother., Vol 48 (2004) pp. 2888-2896) was
analyzed in the presence of different lantibiotics. We could show dose-dependent
cell wall biosynthesis stress of reporter cells in response to the action of the
lantibiotics subtilin produced by B. subtilis, epidermin and gallidermin of
Staphylococcus epidermidis or S. gallinarum, respectively, in both, agar-plate
and liquid culture-based assays. Surprisingly, also cinnamycin of Streptomyces
cinnamoneus cinnamoneus), previously known to bind specifically to
phosphatidylethanolamin of biological membranes, provoked strong cell wall
biosynthetic stress. Our results show that our system can be used for screening
purposes, for example to discover novel inhibitors of cell wall biosynthesis. BACKGROUND: Staphylococcus aureus is a highly adaptable human pathogen and there
is a constant search for effective antibiotics. Fosfomycin is a potent
irreversible inhibitor of MurA, an enolpyruvyl transferase that uses
phosphoenolpyruvate as substrate. The goal of this study was to identify the
pathways and processes primarily affected by fosfomycin at the genome-wide
transcriptome level to aid development of new drugs.
RESULTS: S. aureus ATCC 29213 cells were treated with sub-MIC concentrations of
fosfomycin and harvested at 10, 20 and 40 minutes after treatment. S. aureus
GeneChip statistical data analysis was complemented by gene set enrichment
analysis. A visualization tool for mapping gene expression data into biological
pathways was developed in order to identify the metabolic processes affected by
fosfomycin. We have shown that the number of significantly differentially
expressed genes in treated cultures increased with time and with increasing
fosfomycin concentration. The target pathway - peptidoglycan biosynthesis - was
upregulated following fosfomycin treatment. Modulation of transport processes,
cofactor biosynthesis, energy metabolism and nucleic acid biosynthesis was also
observed.
CONCLUSIONS: Several pathways and genes downregulated by fosfomycin have been
identified, in contrast to previously described cell wall active antibiotics,
and was explained by starvation response induced by phosphoenolpyruvate
accumulation. Transcriptomic profiling, in combination with meta-analysis, has
been shown to be a valuable tool in determining bacterial response to a specific
antibiotic. Charophytes is a green algal group closely related to land plants. We
investigated the effects of antibiotics that interfere with peptidoglycan
biosynthesis on chloroplast division in the desmid Closterium
peracerosum-strigosum-littorale complex. To detect cells just after division, we
used colchicine, which inhibits Closterium cell elongation after division.
Although normal Closterium cells had two chloroplasts before and after cell
division, cells treated with ampicillin, D-cycloserine, or fosfomycin had only
one chloroplast after cell division, suggesting that the cells divided without
chloroplast division. The antibiotics bacitracin and vancomycin showed no
obvious effect. Electron microscopic observation showed that irregular-shaped
chloroplasts existed in ampicillin-treated Closterium cells. Because antibiotic
treatments resulted in the appearance of long cells with irregular chloroplasts
and cell death, we counted cell types in the culture. The results suggested that
cells with one chloroplast appeared first and then a huge chloroplast was
generated that inhibited cell division, causing elongation followed by cell
death. In this study, global intra- and extracellular metabolic profiles were exploited
to investigate the impact of antibiotic compounds with different cellular
targets on the metabolome of Staphylococcus aureus HG001. Primary metabolism was
largely covered, yet uncommon staphylococcal metabolites were detected in the
cytosol of S. aureus, including sedoheptulose-1,7-bisphosphate and the
UDP-MurNAc-pentapeptide with an alanine-seryl residue. By comparing the
metabolic profiles of unstressed and stressed staphylococcal cells in a
time-dependent manner, we found far-ranging effects within the metabolome. For
each antibiotic compound, accumulation as well as depletion of metabolites was
detected, often comprising whole biosynthetic pathways, such as central carbon
and amino acid metabolism and peptidoglycan, purine, and pyrimidine synthesis.
Ciprofloxacin altered the pool of (deoxy)nucleotides as well as peptidoglycan
precursors, thus linking stalled DNA and cell wall synthesis. Erythromycin
tended to increase the amounts of intermediates of the pentose phosphate pathway
and lysine. Fosfomycin inhibited the first enzymatic step of peptidoglycan
synthesis, which was followed by decreased levels of peptidoglycan precursors
but enhanced levels of substrates such as UDP-GlcNAc and alanine-alanine. In
contrast, vancomycin and ampicillin inhibited the last stage of peptidoglycan
construction on the outer cell surface. As a result, the amounts of
UDP-MurNAc-peptides drastically increased, resulting in morphological
alterations in the septal region and in an overall decrease in central
metabolite levels. Moreover, each antibiotic affected intracellular levels of
tricarboxylic acid cycle intermediates. |
Can Levoxyl (levothyroxine sodium) cause insomnia? | Levoxyl monotherapy is associated with increased insomnia compared to a combination of levothyroxine and liothyronine. | OBJECTIVES: To examine the efficacy of combination therapy with levothyroxine
and liothyronine in improvement of general health, psychological problems, and
metabolic status in primary hypothyroidism.
METHODS: Seventy-one patients diagnosed with primary hypothyroidism were
randomly allocated into two study groups: the first group received usual dose of
levothyroxine and the second group received combination of levothyroxine and
liothyronine for at least 4 months. The main outcomes were psychosocial problems
(Goldberg's General Health Questionnaire, GHQ-28), bodyweight, heart rate, blood
pressure, and serum lipid levels.
RESULTS: In both groups serum thyroid-stimulating hormone levels remained
unchanged compared with baseline. Psychosocial scores, body weight, heart rate,
blood pressure, and lipid profile in the two groups remained constant. The only
exception was a small but significant reduction in anxiety/insomnia in combined
treatment group as compared with monotherapy.
CONCLUSIONS: The data do not support the hypothesis that combined therapy
improves the well-being and general health of patients. |
Is fatigue prevalent in patients receiving treatment for glioblastoma? | Yes, fatigue is a common complication of glioblastoma patients receiving chemotherapy or radiotherapy. | In the 1950's it was first observed that mammalian cells exposed to the
halogenated deoxyuridines were more sensitive to ultraviolet light and radiation
than untreated cells. This prompted early clinical trials with bromodeoxyuridine
(BUdR) which showed mixed results. More recently, several Phase I studies, while
establishing the feasibility of continuous intravenous (IV) infusion of BUdR,
have reported significant dose limiting skin and bone marrow toxicities and have
questioned the optimal method of BUdR delivery. To exploit the high mitotic
activity of maligt gliomas relative to surrounding normal brain tissue, we
have developed a permanently implantable infusion pump system for safe,
continuous intraarterial (IA) internal carotid BUdR delivery. Since July 1985,
23 patients with maligt brain tumors (18 grade 4, 5 grade 3) have been
treated in a Phase I clinical trial using IA BUdR (400-600 mg/m2/day X 8 1/2
weeks) and focal external beam radiotherapy (59.4 Gy at 1.8 Gy/day in 6 1/2
weeks). Following initial biopsy/surgery the infusion pump system was implanted;
BUdR infusion began 2 weeks prior to and continued throughout the 6 1/2 week
course of radiotherapy. There have been no vascular complications. Side-effects
in all patients have included varying degrees of anorexia, fatigue, ipsilateral
forehead dermatitis, blepharitis, and conjunctivitis. Myelosuppression requiring
dose reduction occurred in one patient. An overall Kaplan-Meier estimated median
survival of 20 months has been achieved. As in larger controlled series,
histologic grade and age are prognostically significant. We have shown in a
Phase I study that IA BUdR radiosensitization is safe, tolerable, may lead to
improved survival, and appears to be an efficacious primary treatment of
maligt gliomas. OBJECTIVES: The optimal treatment for elderly patients (age >70 years) with
glioblastoma (GBM) remains controversial. We conducted a prospective trial in 43
consecutive elderly patients with GBM treated with hypofractionated radiotherapy
(RT) followed by adjuvant temozolomide.
PATIENTS AND METHODS: Forty-three patients 70 years of age or older with a newly
diagnosed GBM and a Karnofsky performance status (KPS) > or = 60 were treated
with hypofractionated RT (6 fractions of 5 Gy each for a total of 30 Gy over 2
weeks) followed by up to 12 cycles of adjuvant temozolomide (150-200 mg/m(2) for
5 days during each 28 day cycle). The HRQOL was assessed with the EORTC Quality
of Life Questionnaire C30. The primary endpoint was overall survival (OS).
Secondary endpoints included progression free survival (PFS), toxicity and
quality of life.
RESULTS: The median OS was 9.3 months and the median PFS was 6.3 months. The 6
and 12 month survival rates were 86% and 35%, respectively. The 6 and 12 month
PFS rates were 55% and 12%, respectively. In multivariate analysis KPS was the
only significant independent predictive factor of survival (P = 0.008).
Neurological deterioration occurred during or after RT in 16% of patients and
was resolved in most cases with the use of steroids. Grade 3-4 hematologic
toxicity occurred in 28% of patients during the adjuvant chemotherapy treatment
with temozolomide. The treatment had no negative effect on HRQOL, however,
fatigue (P = 0.02) and constipation (P = 0.01) scales worsened over time.
CONCLUSIONS: Hypofractionated RT followed by temozolomide may provide survival
benefit maintaining a good quality of life in elderly patients with GBM. It may
represent a reasonable therapeutic approach especially in patients with less
favourably prognostic factors. A retrospective evaluation of single agent bevacizumab in adults with recurrent
glioblastoma (GBM) with an objective of determining progression free survival
(PFS). There is no standard therapy for recurrent GBM after failure of
alkylator-based chemotherapy. A total of 50 adults, ages 36-70 years (median
64), with recurrent GBM were treated. All patients had previously been treated
with surgery, concurrent radiotherapy and temozolomide, post-radiotherapy
temozolomide and in 34 patients, one salvage regimen (PCV: 21, cyclophosphamide:
13). A total of 13 patients underwent repeat surgery. Patients were treated at
first or second recurrence with bevacizumab, once every 2 weeks, defined as a
single cycle. Neurological evaluation was performed every 2 weeks and
neuroradiographic assessment following the initial 2 cycles of bevacizumab and
subsequently after every 4 cycles of bevacizumab. A total of 468 cycles of
bevacizumab (median 2 cycles; range 1-30) was administered. Bevacizumab-related
toxicity included fatigue (16 patients; 4 grade 3), leukopenia (9; 1 grade 3),
anemia (5; 0 grade 3), hypertension (7; 1 grade 3), deep vein thrombosis (4; 1
grade 3) and wound dehiscence (2; 1 grade 3). 21 patients (42%) demonstrated a
partial radiographic response and 29 (58%) progressive disease following 1-2
cycles of bevacizumab. Time to tumor progression ranged from 0.5 to 15 months
(median: 1.0 months). Survival ranged from 2 to 17 months (median: 8.5 months).
6-month and 12-month PFS were 42% and 22% respectively. Single agent bevacizumab
demonstrated efficacy and acceptable toxicity in this cohort of adults with
recurrent alkylator-refractory GBM. The objective of this phase II single-arm study was to evaluate the efficacy and
safety of pazopanib, a multi-targeted tyrosine kinase inhibitor, against
vascular endothelial growth factor receptor (VEGFR)-1, -2, and -3,
platelet-derived growth factor receptor-alpha and -beta, and c-Kit, in recurrent
glioblastoma. Patients with < or =2 relapses and no prior anti-VEGF/VEGFR
therapy were treated with pazopanib 800 mg daily on 4-week cycles without
planned interruptions. Brain magnetic resoce imaging and clinical
reassessment were made every 8 weeks. The primary endpoint was efficacy as
measured by 6-month progression-free survival (PFS6). Thirty-five GBM patients
with a median age of 53 years and median Karnofsky performance scale of 90 were
accrued. Grade 3/4 toxicities included leukopenia (n = 1), lymphopenia (n = 2),
thrombocytopenia (n = 1), ALT elevation (n = 3), AST elevation (n = 1), CNS
hemorrhage (n = 1), fatigue (n = 1), and thrombotic/embolic events (n = 3); 8
patients required dose reduction. Two patients had a partial radiographic
response by standard bidimensional measurements, whereas 9 patients (6 at the
8-week point and 3 only within the first month of treatment) had decreased
contrast enhancement, vasogenic edema, and mass effect but <50% reduction in
tumor. The median PFS was 12 weeks (95% confidence interval [CI]: 8-14 weeks)
and only 1 patient had a PFS time > or =6 months (PFS6 = 3%). Thirty patients
(86%) had died and median survival was 35 weeks (95% CI: 24-47 weeks). Pazopanib
was reasonably well tolerated with a spectrum of toxicities similar to other
anti-VEGF/VEGFR agents. Single-agent pazopanib did not prolong PFS in this
patient population but showed in situ biological activity as demonstrated by
radiographic responses. ClinicalTrials.gov identifier: NCT00459381. PURPOSE: Amplification of the epidermal growth factor receptor (EGFR) gene
represents one of the most frequent gene alterations in glioblastoma (GBM). In
the current study, we evaluated gefitinib, a potent EGFR inhibitor, in the
treatment of adults with newly diagnosed GBM.
METHODS AND MATERIALS: Ninety-eight patients (96 evaluable) were accrued between
May 18, 2001, and August 2, 2002. All were newly diagnosed GBM patients who were
clinically and radiographically stable/improved after radiation treatment
(enrollment within 5 weeks of radiation completion). No prior chemotherapy was
permitted. EGFR amplification/mutation, as assessed by fluorescence in situ
hybridization and immunohistochemistry, was not required for treatment with
gefitinib but was studied when tissues were available. Gefitinib was
administered at 500 mg each day; for patients receiving dexamethasone or
enzyme-inducing (CYP3A4) agents, dose was escalated to a maximum of 1,000 mg QD.
Treatment cycles were repeated at 4-week intervals with brain magnetic resoce
imaging at 8-week intervals.
RESULTS: Overall survival (OS; calculated from time of initial surgery) at 1
year (primary end point) with gefitinib was 54.2%, which was not statistically
different compared with that of historical control population (48.9%, data from
three previous Phase III North Central Cancer Treatment Group studies of newly
diagnosed GBM patients). Progression-free survival (PFS) at 1 year post-RT
(16.7%) was also not significantly different to that of historical controls
(30.3%). Clinical outcome was not affected by EGFR status (amplification or vIII
mutation). Fatigue (41%), rash (62%), and loose stools (58%) constituted the
most frequent adverse events, the majority of these being limited to Grade 1/2.
Of note, the occurrence of drug-related adverse effects, such as loose stools
was associated with improved OS.
CONCLUSIONS: In our evaluation of nearly 100 patients with newly diagnosed GBM,
treatment with adjuvant gefitinib post-radiation was not associated with
significant improvement in OS or PFS. However, patients who experienced
gefitinib-associated adverse effects (rash/diarrhea) did demonstrate improved
OS. BACKGROUND: The authors evaluated a 3-week schedule of bevacizumab in patients
with recurrent high-grade glioma (HGG).
METHODS: Patients received bevacizumab 15 mg/kg every 3 weeks and were evaluated
every 6 weeks until tumor progression. Tissue correlates were used to quantify
tumor content of vascular endothelial growth factor A (VEGFA) and vascular
endothelial growth factor receptor-2 (VEGFR2).
RESULTS: Of 61 patients who were treated (35 men and 26 women; median age, 52
years; age range, 21-78 years), 50 patients had glioblastoma multiforme (GBM),
and 11 patients had anaplastic glioma (AG). The median number of previous
chemotherapies was 2 (range, 1-5 previous chemotherapies), and 16 patients had
received ≥3 previous chemotherapies. The median number of bevacizumab doses was
4 (range, 1-20 doses), and 45% of patients received >5 doses. The toxicities
observed were primarily grade 1 and 2, and the most common were fatigue,
hypertension, and headache. One grade 2 intratumoral bleed and 1 bowel
perforation were reported. For patients with GBM, the 6-month progression-free
survival rate was 25%, the median time to tumor progression was 10.8 weeks, and
the median overall survival was 25.6 weeks. The best response included a partial
response in 15 patients (24.5%) and stable disease in 31 patients (50.8%)
patients; radiographic recurrence patterns included increased changes in fluid
attenuation inversion recovery (24%) and multifocal recurrence (20%). The median
survival after bevacizumab failure was 10 weeks. The ratio of tumor VEGFA/VEGFR2
was increased in patients aged >55 years; an increased VEGFA/VEGFR2 ratio was
correlated nonsignificantly with decreased survival (P = .052).
CONCLUSIONS: An every-3-week schedule of bevacizumab had antitumor activity and
was relatively nontoxic for patients with recurrent HGG. The predictive value of
VEGFA/VEGFR2 in tumor will require validation in a larger patient cohort. External beam radiation therapy (XRT) with concomitant temozolomide and 6 cycles
of adjuvant temozolomide (5/28-day schedule) improves survival in patients with
newly diagnosed glioblastoma compared with XRT alone. Studies suggest that
dose-dense temozolomide schedules and addition of cytostatic agents may further
improve efficacy. This factorial design phase I/II protocol tested dose-dense
temozolomide alone and combined with cytostatic agents. Patients with newly
diagnosed glioblastoma received fractionated XRT to 60 Gy concomitant with
temozolomide (75 mg/m²)/day for 42 days). In the phase I portion, patients with
stable disease or radiologic response 1 month after chemoradiation were
randomized to adjuvant temozolomide alone (150 mg/m²/day, 7/14-day schedule) or
with doublet combinations of thalidomide (400 mg/day), isotretinoin (100
mg/m²/day), and/or celecoxib (400 mg twice daily), or all 3 agents. Toxicity was
assessed after 4 weeks. Among 54 patients enrolled (median age, 52 years; median
Karnofsky performance status, 90), adjuvant treatment was not administered to 12
(22%), primarily because of disease progression (n = 10). All combinations were
well tolerated. Grade 3/4 lymphopenia developed in 63% of patients, but no
related infections occurred. One patient treated with temozolomide plus
isotretinoin plus thalidomide had dose-limiting grade 3 fatigue and rash, and 1
patient receiving all 4 agents had dose-limiting grade 4 neutropenia. Venous
thrombosis occurred in 7 patients, 4 of whom received thalidomide. From study
entry, median survival was 20 months and the 2-year survival rate was 40%.
Multiple cytostatic agents can be safely combined with dose-dense temozolomide.
The factorial-based phase II portion of this study is currently ongoing. OBJECTIVE: The combination of irinotecan-bevacizumab is effective in patients
with glioblastoma relapse but fatigue is a commonly reported side effect. The
objective of this study was to evaluate the level and evolution of fatigue in a
series of patients treated with therapeutic combination.
PATIENTS AND METHODS: We used two self-evaluation tools to quantify the physical
and emotional aspects of this fatigue. The Norris Visual Analog Scale (VAS
Norris) and the Multidimensional Fatigue Inventory-20 (MFI) tools were
undertaken by 39 patients with glioblastoma relapse treated with
irinotecan-bevacizumab, initially before the first cycle and thereafter with
each cycle up until tumor progression.
RESULTS: Analysis of the results of the VAS Norris scale did not demonstrate an
increase in emotional fatigue but did show an increase in physical fatigue that
did not reach statistical significance. With regards to the MFI 20 tool,
analysis of the results demonstrated a significant increase in general
(P=0.0260) as well as physical (P=0.0141) fatigue but there was no difference in
the other indices.
CONCLUSION: This study demonstrated a progressive increase in physical fatigue
in patients with glioblastoma relapse treated with irinotecan-bevacizumab. We
suspect that this is as a direct consequence of the treatment. There are however
other confounding factors: insidious tumour progression not detected on
follow-up imaging or delayed side effects of the initial
radiotherapy-chemotherapy. PURPOSE: Radiotherapy (RT) and chemotherapy may prolong survival in older
patients (age ≥70 years) with glioblastoma multiforme (GBM), although the
survival benefits remain poor. This Phase II multicenter study was designed to
evaluate the efficacy and safety of an abbreviated course of RT plus concomitant
and adjuvant temozolomide (TMZ) in older patients with GBM.
PATIENTS AND METHODS: Seventy-one eligible patients 70 years of age or older
with newly diagnosed GBM and a Karnofsky performance status ≥60 were treated
with a short course of RT (40 Gy in 15 fractions over 3 weeks) plus TMZ at the
dosage of 75 mg/m(2) per day followed by 12 cycles of adjuvant TMZ (150-200
mg/m(2) for 5 days during each 28-day cycle). The primary endpoint was overall
survival (OS). Secondary endpoints included progression-free survival and
toxicity.
RESULTS: The Median OS was 12.4 months, and the 1-year and 2-year OS rates were
58% and 20%, respectively. The median and 1-year rates of progression-free
survival were 6 months and 20%, respectively. All patients completed the planned
programme of RT. Grade 3 or 4 adverse events occurred in 16 patients (22%).
Grade 3 and 4 neutropenia and/or thrombocytopenia occurred in 10 patients (15%),
leading to the interruption of treatment in 6 patients (8%). Nonhematologic
Grade 3 toxicity was rare, and included fatigue in 4 patients and cognitive
disability in 1 patient.
CONCLUSIONS: A combination of an abbreviated course of RT plus concomitant and
adjuvant TMZ is well tolerated and may prolong survival in elderly patients with
GBM. Future randomized studies need to evaluate the efficacy and toxicity of
different schedules of RT in association with chemotherapy. Vorinostat, a histone deacetylase (HDAC) inhibitor, has shown evidence of
single-agent activity in glioblastoma (GBM), and in preclinical studies, we have
demonstrated significant synergistic cytotoxicity between HDAC inhibitors and
proteasome inhibitors in GBM cell lines. We therefore conducted a phase II trial
to evaluate the efficacy of vorinostat in combination with the proteasome
inhibitor bortezomib in patients with recurrent GBM. Vorinostat was administered
at a dose of 400 mg daily for 14 days of a 21-day cycle, and bortezomib was
administered at a dose of 1.3 mg/m(2) intravenously on days 1, 4, 8, and 11 of
the cycle. A total of 37 patients were treated, and treatment was well
tolerated: grade 3, 4 nonhematologic toxicity occurred in 30% of patients and
consisted mainly of fatigue (14%) and neuropathy (5%); grade 3, 4 hematologic
toxicity occurred in 37% of patients and consisted of thrombocytopenia (30%),
lymphopenia (4%), and neutropenia (4%). The trial was closed at the
predetermined interim analysis, with 0 of 34 patients being progression-free at
6 months. One patient achieved a partial response according to the Macdonald
criteria. The median time to progression for all patients was 1.5 months (range,
0.5-5.6 months), and median overall survival (OS) was 3.2 months. Patients who
had received prior bevacizumab therapy had a shorter time to progression and OS,
compared with those who had not. On the basis of the results of this phase II
study, further evaluation of the vorinostat-bortezomib combination in GBM
patients in this dose and schedule is not recommended. Single-agent sunitinib, an oral small molecule inhibitor of multiple tyrosine
kinase receptors, was evaluated for treatment of patients with recurrent
glioblastoma (GB) and anaplastic astrocytoma (AA). Fourteen AA and 16 GB
patients, all previously treated with surgery, radiotherapy, and temozolomide,
were enrolled in a prospective phase II study at either first or second relapse.
Patients were treated with daily sunitinib for 4 consecutive weeks, followed by
a 2-week break. For AA patients, the most common side effects were fatigue (86
%), diarrhea (43 %), hand-foot syndrome (36 %), neutropenia (36 %),
thrombocytopenia (36 %), and nausea (29 %). In the GB cohort, the most common
side effects were fatigue (56 %), diarrhea (44 %), neutropenia (31 %), and
thrombocytopenia (25 %). Six of 14 (43 %) AA and 5 of 16 (31 %) GB patients
experienced grade 3 or greater toxicities. Five patients discontinued study due
to drug toxicities. There were no partial or complete responses in either
cohort; 8/14 (57 %) AA and 5/16 (31 %) GB patients had stable disease at the
first planned assessment. Progression-free survival at 6 months was 21.5 % (AA)
and 16.7 % (GB). Median overall survival was 12.1 months (AA) and 12.6 months
(GB). These results are comparable to those reported in the literature in
patients treated with standard cytotoxic therapies. This is the largest reported
trial of sunitinib in recurrent maligt astrocytic gliomas to date, as well as
contains the largest AA cohort. Nonetheless, sunitinib did not demonstrate
significant anti-glioma activity in patients with recurrent maligt astrocytic
gliomas. The Radiation Therapy Oncology Group (RTOG) initiated the single-arm, phase II
study 9806 to determine the safety and efficacy of daily thalidomide with
radiation therapy in patients with newly diagnosed glioblastoma. Patients were
treated with thalidomide (200 mg daily) from day one of radiation therapy,
increasing by 100-200 to 1,200 mg every 1-2 weeks until tumor progression or
unacceptable toxicity. The median survival time (MST) of all 89 evaluable
patients was 10 months. When compared with the historical database stratified by
recursive partitioning analysis (RPA) class, this end point was not different
[hazard ratio (HR) = 1.18; 95 % CI: 0.95-1.46; P = 0.93]. The MST of RPA class
III and IV patients was 13.9 versus 12.5 months in controls (HR = 0.99; 95 % CI:
0.73-1.36; P = 0.48), and 4.3 versus 8.6 months in RPA class V controls
(HR = 1.63, 95 % CI: 1.17-2.27; P = 0.99). In all, 34 % of patients discontinued
thalidomide because of adverse events or refusal. The most common grade 3-4
toxicities were venous thrombosis, fatigue, skin reactions, encephalopathy, and
neuropathy. In conclusion, thalidomide given simultaneously with radiation
therapy was safe, but did not improve survival in patients with newly diagnosed
glioblastoma. BACKGROUND: Bevacizumab, a humanized recombit anti-vascular endothelial
growth factor antibody, was approved in Canada in 2010 for the treatment of
high-grade glioma. We report the effectiveness and safety of bevacizumab in the
treatment of patients with recurrent high-grade gliomas at a single institution.
METHODS: Twenty-seven consecutive patients with high-grade glioma (anaplastic
glioma and glioblastoma) at first or subsequent relapse were treated with
bevacizumab alone or in combination with chemotherapy. The primary endpoint was
progression-free survival (PFS) and secondary endpoints were objective response
rate, six month PFS, overall survival (OS), and safety profile.
RESULTS: The clinical benefit rate (complete and partial responses plus stable
disease) was 59%. Median PFS was 4.3 (95% CI, 3.0-10.9) months, with a six month
PFS rate of 43%. Median OS after current relapse was 8.9 (95% CI, 5.8-not
reached) months. Ten episodes of grade 3/4 adverse events were observed in nine
patients, including fatigue (n = 3), thrombocytopenia (n = 4), and
myelotoxicity, febrile neutropenia, and pulmonary embolism (each n = 1).
CONCLUSIONS: We consider the efficacy and safety profile of bevacizumab is
comparable to other cohorts of patients treated for recurrent high-grade glioma
at other international institutions. PURPOSE: To describe the quality of life (QOL) in elderly patients with
glioblastoma (GBM) treated with an abbreviated course of radiation therapy (RT;
40 Gy in 15 fractions) plus concomitant and adjuvant temozolomide (TMZ).
METHODS AND MATERIALS: Health-related QOL (HRQOL) was assessed by European
Organisation for Research and Treatment of Cancer (EORTC) Quality of Life
Questionnaire Core-30 (QLQ-C30, version 3) and EORTC Quality of Life
Questionnaire Brain Cancer Module (QLQ-BN20). Changes from baseline in the score
of 9 preselected domains (global QLQ, social functioning, cognitive functioning,
emotional functioning, physical functioning, motor dysfunction, communication
deficit, fatigue, insomnia) were determined 4 weeks after RT and thereafter
every 8 weeks during the treatment until disease progression. The proportion of
patients with improved HRQOL scores, defined as a change of 10 points or more,
and duration of changes were recorded.
RESULTS: Sixty-five patients completed the questionnaires at baseline. The
treatment was consistently associated with improvement or stability in most of
the preselected HRQOL domains. Global health improved over time; mean score
differed by 9.6 points between baseline and 6-month follow-up (P=.03). For
social functioning and cognitive functioning, mean scores improved over time,
with a maximum difference of 10.4 points and 9.5 points between baseline and
6-month follow-up (P=.01 and P=.02), respectively. By contrast, fatigue worsened
over time, with a difference in mean score of 5.6 points between baseline and
4-month follow-up (P=.02).
CONCLUSIONS: A short course of RT in combination with TMZ in elderly patients
with GBM was associated with survival benefit without a negative effect on HRQOL
until the time of disease progression. |
List two common features of Tay syndrome. | Tay syndrome is a rare autosomal recessive genetic disorder characterized by congenital ichthyosis and trichothiodystrophy (abnormal brittle hair). Other less common features of this syndrome are photosensitivity, low birth weight, short stature, mental retardation, delayed neuromuscular development and other CNS anomalies, dysplasia of nails, hypoplasia of subcutaneous fatty tissue, prematurely aged facial appearance, hypogonadism, cataracts, osteosclerosis, dysphonia, and increased susceptibility to infections. | Trichothiodystrophy (brittle sulfur-deficient hair) is a marker for several
autosomal recessive neurocutaneous syndromes with neurological manifestations
and mental retardation. In Tay syndrome, the trichothiodystrophy is accompanied
by congenital ichthyosis, short stature, delayed physical and mental development
and pyramidal tract signs with increase in muscular tone and brisk tendon
reflexes. The pathogenesis of these neurological manifestations is not fully
elucidated. We present a case of Tay syndrome in which a cranial MRI revealed an
almost total lack of myelin within the cerebral hemispheres and a patchy
hypomyelination of the cerebellum. In accordance, a strongly prolonged visual
evoked response pointed to a dysfunction of the white matter in Tay syndrome. This paper reports on the orthopaedic rehabilitation of a patient with
Tay-syndrome. Tay-syndrome is a rare monogen-inherited ektodermal dysplastic
syndrome with ichtyosis, fragility of the hair and physical and mental
retardation. The congenital ichtyosis is ubiquitous. Only the skin on the
flexion side of the extremity joints are not involved (orthocerathosis combined
with paraceratotic strings). In this case, a young boy developed bilateral
subluxation of the hips and was not able to stand or walk freely. Contemporary
pre- and neonatal care has prolonged the survival of newborns with severe
genodermatoses, including this syndrome. In this case, it has provided the
necessity for orthopaedic treatment of the problems caused by osteosclerosis and
muscular spasticity. Trichothiodystrophy comprises a heterogeneous group of autosomal recessive
entities. This fact gives rise to different interrelated neuroectodermal
disorders. From a structural point of view these features are the result of the
low tissue sulfur content. We report a case of trichothiodystrophy initially
classified as Tay syndrome that based on clinical features, complementary exams
as well as on the disease evolution was labelled as PIBIDS syndrome. Tay syndrome or IBIDS is a rare autosomal recessive genetic disorder
characterized by congenital ichthyosis and abnormal brittle hair
(trichothiodystrophy). Other features include photosensitivity, abnormal nails
and multiple developmental defects affecting organs mainly derived from
neuroectoderm. The exact prevalence of this condition is not known, but up to
1991, clinical data of 15 cases with IBIDS were published .We report a case of
Tay syndrome with additional features of Duane's retraction syndrome and Perthes
disease, which have not yet been reported in literature. |
Which cell types are known to be driving Rheumatoid Arthritis? | Macrophages, T cells and their respective cytokines play a pivotal role in RA. Rheumatoid arthritis synovial fibroblasts (RASFs) constitute a quite unique cell type that distinguishes RA from other inflammatory conditions of the joints. Activated synovial fibroblasts (SFs) have the ability to invade joint cartilage, actively contributing to joint destruction in RA. | The proteins of homeobox (HOX) genes are transcription regulators involved in
cell type-specific differentiation and patterning of the body plan in
vertebrates. Particularly, the HOXD family is involved in limb formation in mice
and chicks. There is also some evidence that the HOXD9 gene, a member of the
HOXD family, is involved in the pathology of rheumatoid arthritis (RA). The
purpose of the present study was to determine if the HOXD9 protein was expressed
in RA synovium and then to characterize the HOXD9-expressing cell. Western
blotting and immunohistochemical analysis showed that the HOXD9 protein was
expressed in the synovium from patients with RA, but not in those from patients
with osteoarthritis or healthy individuals. The HOXD9-positive cells were
localized in both the lining and sublining areas of the synovium. Furthermore,
fluorescent double-staining showed that the HOXD9 protein was expressed in
fibroblast-like synoviocytes (FLS). These findings not only indicate that the
HOXD9 gene is exclusively expressed in the RA synovium but also suggest that the
HOXD9 gene contributes to the pathology of rheumatoid arthritis through the FLS. OBJECTIVE: Treatment of rheumatoid arthritis (RA) with tumor necrosis factor
(TNF) antagonists is highly effective, but their mechanisms of action are not
completely clear. Since anti-TNF therapy induces a decrease in synovial
cellularity, this study focused on the modulation of RA synovial apoptosis
following treatment with either soluble TNF receptor (etanercept) or TNF
chimeric monoclonal antibody (infliximab).
METHODS: Apoptosis (TUNEL and active caspase 3 staining) and cell surface
markers were evaluated by immunohistochemistry in synovial biopsy samples
obtained before and after 8 weeks of treatment with etanercept (12 patients) or
infliximab (9 patients). We also determined by flow cytometry the in vitro
effect of etanercept and infliximab on apoptosis of RA mononuclear cells derived
from the synovial fluid (SF) and peripheral blood (PB).
RESULTS: Eight weeks of treatment with etanercept and with infliximab
significantly increased synovial apoptosis. This change was accompanied by a
significant decrease in the synovial monocyte/macrophage population. The
decrease in lymphocyte numbers did not reach statistical significance. In vitro,
24 hours of incubation with either etanercept or infliximab induced apoptosis of
the SF monocyte/macrophage population. PB monocyte/macrophages were less
susceptible to anti-TNF-mediated apoptosis. No changes in the rate of apoptosis
were observed in the lymphocyte population derived from either SF or PB.
CONCLUSION: In RA patients, both etanercept and infliximab are able to induce
cell type-specific apoptosis in the monocyte/macrophage population. This
suggests a potential pathway that would account for the diminished synovial
inflammation and the decreased numbers of synovial macrophages evident after TNF
blockade. Rheumatoid arthritis (RA) is a chronic autoimmune-disease of unknown origin that
primarily affects the joints and ultimately leads to their destruction. The
involvement of immune cells is a general hallmark of autoimmune-related
disorders. In this regard, macrophages, T cells and their respective cytokines
play a pivotal role in RA. However, the notion that RA is a primarily
T-cell-dependent disease has been strongly challenged during recent years.
Rather, it has been understood that resident, fibroblast-like cells contribute
significantly to the perpetuation of disease, and that they may even play a role
in its initiation. These rheumatoid arthritis synovial fibroblasts (RASFs)
constitute a quite unique cell type that distinguishes RA from other
inflammatory conditions of the joints. A number of studies have demonstrated
that RASFs show alterations in morphology and behaviour, including molecular
changes in signalling cascades, apoptosis responses and in the expression of
adhesion molecules as well as matrix-degrading enzymes. These changes appear to
reflect a stable activation of RASFs, which occurs independently of continuous
exogenous stimulation. As a consequence, RASFs are no longer considered passive
bystanders but active players in the complex intercellular network of RA. Rheumatoid arthritis (RA) is characterized by the recruitment of leukocytes and
the accumulation of inflammatory mediators within the synovial compartment.
Release of the chemokine CCL18 has been widely attributed to antigen-presenting
cells, including macrophages and dendritic cells. This study investigates the
production of CCL18 in polymorphonuclear neutrophils (PMN), the predomit cell
type recruited into synovial fluid (SF). Microarray analysis, semiquantitative
and quantitative reverse transcriptase polymerase chain reaction identified SF
PMN from patients with RA as a novel source for CCL18 in diseased joints. Highly
upregulated expression of other chemokine genes was observed for CCL3, CXCL8 and
CXCL10, whereas CCL21 was downregulated. The chemokine receptor genes were
differentially expressed, with upregulation of CXCR4, CCRL2 and CCR5 and
downregulation of CXCR1 and CXCR2. In cell culture experiments, expression of
CCL18 mRNA in blood PMN was induced by tumor necrosis factor alpha, whereas
synthesis of CCL18 protein required additional stimulation with a combination of
IL-10 and vitamin D3. In comparison, recruited SF PMN from patients with RA were
sensitized for CCL18 production, because IL-10 alone was sufficient to induce
CCL18 release. These results suggest a release of the T cell-attracting CCL18 by
PMN when recruited to diseased joints. However, its production is tightly
regulated at the levels of mRNA expression and protein synthesis. Fibroblast-like synoviocytes (FLS) are resident mesenchymal cells of synovial
joints that have been recognized to play an increasingly important role in the
pathogenesis of rheumatoid arthritis (RA). Activation of FLS in the setting of
RA leads to the production of a broad array of cell surface and soluble
mediators that help to recruit, retain, and activate both cells of the immune
system and resident joint cells, leading to the promotion of ongoing
inflammation and tissue destruction. The ability of FLS to stimulate both
inflammation and tissue damage suggests that this cell type may be a unique
target for the treatment of inflammatory arthritis. Greater understanding of how
FLS are activated and how they interact with other cells in the RA synovium may
provide insights that allow development of novel agents for RA therapy. Mesenchymal stromal cells (MSCs) represent a unique cell type with
anti-proliferative effects on activated T and B cells. Based on our observation
of differences between rheumatoid arthritis and osteoarthritis bone marrow B
cells we hypothesized that rheumatoid arthritis bone marrow MSCs may enhance
B-cell survival. We aimed to compare the effect of rheumatoid arthritis and
osteoarthritis bone marrow-derived MSCs (rheumatoid arthritis MSCs,
osteoarthritis MSCs) on the survival of healthy donor purified B cells.
Rheumatoid arthritis and osteoarthritis MSCs were isolated from patients
undergoing hip replacement surgery, and cultured in vitro for 2-5 passages.
Washed cells were co-cultured with CD20+ B cells for 30-90 hours. Cell survival
was analysed using 7-amino-actinomycin D labelling by flow cytometry. Expression
of mRNA and protein was determined by RT-PCR and flow cytomery. Co-culture with
both rheumatoid arthritis MSCs and osteoarthritis MSCs significantly enhanced
B-cell survival, the effect being more prominent in rheumatoid arthritis MSCs.
Both types of MSCs displayed expression of B cell-activating factor mRNA and
protein. Blocking B cell-activating factor signalling from MSCs by specific
anti-B cell-activating factor and anti-B cell-activating factor receptor
antibodies weakly reversed the effect of MSCs on B-cell survival mainly in
rheumatoid arthritis MSCs. MSC interaction with B cells provides stimuli for
B-cell survival and therefore may contribute to the pathogenesis of rheumatoid
arthritis. MSC-derived factors other than B cell-activating factor are likely to
contribute to this effect. This feature is more prominent in rheumatoid
arthritis MSCs, possibly due to the B cell-activating factor. Cell migration is a central part of physiological and pathophysiological
processes including wound healing, immune defense, matrix remodeling and organ
homeostasis. Different cell types have migratory potential including cells of
the immune system and cells required in wound healing and tissue repair. These
cells migrate locally through the tissue to the site of damage. The fibroblast
is a central cell type of wound healing. In rheumatoid arthritis (RA), activated
synovial fibroblasts (SFs) have the ability to invade joint cartilage, actively
contributing to joint destruction in RA. Recently, RASFs have been shown to be
able to migrate to non-affected areas and joints through the blood stream and to
invade distant cartilage. RASFs most likely use similar mechanisms comparable to
lymphocytes and tumor cells for long-distance and vascular trans-migration.
Future experiments will address the goal to keep the transformed-appearing
fibroblasts in the affected joints using therapeutical strategies that inhibit
the pathophysiological changes of transformed-appearing RASFs but do not
interfere with the physiological processes of 'normal' fibroblasts. IL-1R-associated kinases (IRAKs) are important mediators of MyD88-dependent
signaling by the TLR/IL-1R superfamily and facilitate inflammatory responses.
IRAK4 and IRAK1 function as active kinases and as scaffolds for protein-protein
interactions. We report that although IRAK1/4 kinase activity is essential for
human plasmacytoid dendritic cell (pDC) activation, it is dispensable in B, T,
dendritic, and monocytic cells, which is in contrast with an essential active
kinase role in comparable mouse cell types. An IRAK1/4 kinase inhibitor
abrogated TLR7/9-induced IFN-α responses in both mouse and human pDCs, but other
human immune cell populations activated via TLR7/9 or IL-1R were refractory to
IRAK4 kinase inhibition. Gene ablation experiments using small interfering RNA
demonstrated an essential scaffolding role for IRAK1 and IRAK4 in
MyD88-dependent signaling. Finally, we demonstrate that autoimmune patient
(systemic lupus erythematosus and rheumatoid arthritis) serum activates both pDC
and B cells, but IRAK1/4 kinase inhibition affects only the pDC response,
underscoring the differential IRAK1/4 functional requirements in human immune
cells. These data reveal important species differences and elaborate cell type
requirements for IRAK1/4 kinase activity. PURPOSE OF REVIEW: A significant number of loci implicated in rheumatoid
arthritis (RA) susceptibility have been highlighted by genome-wide association
studies (GWAS). Here, we review the recent advances of GWAS in understanding the
genetic architecture of RA, and place these findings in the context of RA
pathogenesis.
RECENT FINDINGS: Although the interpretation of GWAS findings in the context of
the disease biology remains challenging, interesting observations can be
highlighted. Integration of GWAS results with cell-type specific gene expression
or epigenetic marks have highlighted regulatory T cells and CD4 memory T cells
as critical cell types in RA. In addition, many genes in RA loci are involved in
the nuclear factor-kappaB signaling pathway or the Janus kinase (JAK)-signal
transducers and activators of transcription (STAT) signaling pathway. The
observation that these pathways are targeted by several approved drugs used to
treat the symptoms of RA highlights the promises of human genetics to provide
insights in the disease biology, and help identify new therapeutic targets.
SUMMARY: These findings highlight the promises and need of future studies
investigating causal genes and underlined mechanisms in GWAS loci to advance our
understanding of RA. |
What is the association between personality trait of neuroticism and risk for Alzheimer's disease? | High neuroticism is associated with increased risk to develop Alzheimer's disease. Greater neuroticism is also associated more advanced Alzheimer's disease neuropathology and younger age of dementia onset. Neuroticism's association with late-life dementia mainly reflects vulnerability to stress and anxiety. Neuroticism moderates the relationship between APOE-4 genotype and cognitive outcomes in elderly. Neuroticism also predicts Mild Cognitive Impairment, Aging-Associated Cognitive Decline and cognitive decline among elderly. Alzheimer's disease patients have greater neuroticism relative to controls. | Using the NEO Personality Inventory (NEO-PI), we evaluated caregivers'
perceptions of personality prior to symptom onset and current personality in 36
individuals with a clinical diagnosis of dementia of the Alzheimer's type (DAT).
Caregivers also completed the self form of the NEO-PI and an index of objective
and subjective burden. Personality change in DAT was consistent with previous
reports of increased neuroticism, decreased extraversion, and decreased
conscientiousness, with smaller decreases in openness and agreeableness.
Significant relationships were found among perceived present patient
personality, caregiver personality, and caregiver burden. Regression analyses
indicated that present patient conscientiousness and caregiver neuroticism were
the best predictors of both objective and subjective burden, and these variables
were found to contribute independently to caregivers' reported level of burden.
To the extent that caregivers perceive specific behaviors and interferences
negatively, cognitive and supportive interventions are likely to prove extremely
beneficial. OBJECTIVE: To identify specific premorbid personality traits in patients with
Alzheimer's disease (AD).
DESIGN: A prospective case-control study.
SETTING: A memory clinic of a department of geriatric medicine in a teaching
hospital.
PATIENTS: Fifty-six consecutive patients with probable AD. Sixty-five controls
with Parkinson's disease (PD).
MEASURES: Premorbid personality traits were assessed using the relative rating
version of the Munich Personality Test (MPT).
RESULTS: The AD patients showed higher neuroticism than the controls with PD
(p=0.013). In comparison with MPT normative values for psychiatric inpatients,
the AD patients scored significantly (p<0.05) lower on neuroticism and higher on
frustration tolerance and rigidity.
CONCLUSION: Our results support the assumption of specific premorbid
characteristics in AD patients, ie increased neuroticism and rigidity. More
research is needed to confirm the existence of typical premorbid personality
traits in AD. Studying the cognitive and immunological changes that occur in old age as well
as genetic function have been considered an important subject to differentiate
between normal brain aging and early dementia especially Alzheimer's disease.
The aim of this study is to stress on age-related neuropsychological and
electrophysiological (P(300)) changes in normal Egyptian subjects, to throw
light on the value of genetic (Apo-E(4) genotype) and immunological markers
[interleukin-6 (IL-6) and intercellular adhesion molecules (ICAM-1) in the
serum] as tools used in early detection of cognitive decline in cerebral aging.
Ninety-four normal Egyptian subjects (below and above 60 years) were submitted
to the following: (1) neuropsychological tests for testing memory, perception,
psychomotor performance and attention, (2) Eysenck Personality Questionnaire
(EPQ) for personality traits, (3) event-related potential study (P(300), latency
and amplitude), (4) genetic test for detection of Apolipoprotein E genotype and
(5) immunological studies including detection of the level of IL-6 and ICAM-1 in
serum. There was a significant impairment of memory, psychomotor performance and
perception in elderly subjects particularly males and subjects with low level of
education. Regarding personality, significantly high scores were obtained in
neuroticism scale of EPQ in elderly subjects. Apo-E(3)/E(3) was the most common
genotype encountered in Egyptian subjects (49.1%). It was found that subjects
with Apo-E(4) genotype did significantly worse in scores of intentional memory
test (sensory memory) when compared with other genotypes. Statistically
significant impairment in attention and sensory memory was found in subjects
with high IL-6 level. This could not be detected in subjects with high ICAM-1
level. In conclusion, advancing age and lower levels of education are considered
risk factors for cognitive decline in normal brain aging. Neuropsychological
tests remain as the highly sensitive tools for detection of early cognitive
impairment. Neurotic traits are more encountered in old age. Apo-E(4) genotype
is associated with significant sensory (intentional) memory impairment. High
IL-6 level in the serum is accompanied by significant impairment in attention
and sensory (intentional) memory. The association between distress proneness and cognitive decline was examined in
older residents of a biracial community in Chicago. At baseline, participants
completed four cognitive tests that yielded a global measure (baseline
mean=101.2; standard deviation (SD)=7.8), and a brief measure of the tendency to
experience negative emotions (mean=16.5; SD=6.7) based on the Neuroticism scale
of the NEO Five-Factor Inventory. Cognitive testing was repeated twice at
three-year intervals. In mixed models that controlled age, sex, race, and
education, for each point on the distress proneness scale, global cognitive
score was 0.12 unit lower at baseline (p<0.001) and annual rate of decline
increased by 0.01 unit (p=0.002), or about 2%. Thus, cognitive decline was about
30% faster in a person highly prone to distress (score=24, 90th percentile)
compared to the one low in distress proneness (score=9, 10th percentile). This
effect was unchanged after controlling for level of cognitive activity or
excluding people with cognitive impairment at baseline, but it was reduced to a
trend (p=0.059) after controlling for depressive symptoms. The results suggest
that the tendency to experience psychological distress is associated with
increased cognitive decline in old age. OBJECTIVE: The objective of this study was to test the association of the
personality traits of neuroticism and extraversion with risk of death in old
age.
METHODS: A census was taken of a geographically defined urban community in
Chicago, and those aged 65 years or older were invited to participate in an
in-home interview; 6158 (79% of those eligible) did so. The interview included
brief measures of neuroticism and extraversion, medical history, and questions
about current participation in cognitive, social, and physical activities. Vital
status was subsequently monitored. The association of each trait with risk of
death was examined in a series of accelerated failure-time models that
controlled for age, sex, race, and education.
RESULTS: During a mean of more than 6 years of observation, 2430 persons (39.5%)
died. A high level of neuroticism (score = 27; 90th percentile) was associated
with a 33% increase in risk of death compared with a low level of neuroticism
(score = 9; 10th percentile). A high level of extraversion (score = 33; 90th
percentile) was associated with a 21% decrease in risk of death compared with a
low level (score = 18; 10th percentile). Adjustment for medical conditions and
health-related variables did not substantially affect results, but adjusting for
baseline levels of cognitive, social, and physical activity reduced the
association of both traits with mortality.
CONCLUSIONS: The results suggest that higher extraversion and lower neuroticism
are associated with reduced risk of mortality in old age and that these
associations are mediated in part by personality-related patterns of cognitive,
social, and physical activity. Clinical and pathological data from the Rush Memory and Aging Project were used
to test the hypothesis that distress proneness is associated with increased risk
of Alzheimer's disease (AD). More than 600 older persons without dementia
completed a 6-item measure of neuroticism, a stable indicator of proneness to
psychological distress. At annual intervals thereafter, they underwent uniform
evaluations that included clinical classification of AD and administration of 18
cognitive tests. Those who died underwent brain autopsy from which composite
measures of AD pathology were derived. During a mean of about 3 years of
follow-up, 55 people were clinically diagnosed with AD. In analyses that
controlled for age, sex, and education, persons with a high level of distress
proneness (score = 24, 90th percentile) were 2.7 times more likely to develop AD
than those not prone to distress (score = 6, 10th percentile). Adjustment for
depressive symptomatology or frequency of cognitive, social, and physical
activity did not substantially change this effect. Distress proneness was also
associated with more rapid cognitive decline. Among 45 participants who died and
underwent brain autopsy, distress proneness was unrelated to diverse measures of
AD pathology and was inversely related to cognition after controlling for AD
pathology. The results support the hypothesis that distress proneness is
associated with increased risk of dementia and suggest that neurobiologic
mechanisms other than AD pathology may underlie the association. OBJECTIVE: The objective of this study was to test whether common age-related
neuropathology could account for the relation of chronic distress to dementia.
METHODS: In a selected cohort of more than 1000 older Catholic clergy members
undergoing annual clinical evaluations, 326 persons died, of whom 306 (94%)
underwent brain autopsy, the results of which were available in 219 (mean age at
death = 85.4, standard deviation [SD] = 6.6; mean postmortem interval = 7.6
hours, SD = 6.9). A composite measure of chronic distress was constructed from
standard measures of two traits, neuroticism and anxiety proneness, completed at
baseline, and of depressive symptoms, completed annually. Dementia was diagnosed
according to standard criteria and cognition was assessed with previously
established composite measures based on a uniform clinical evaluation that took
place a mean of 9.1 months before death (SD = 9.5). On postmortem examination,
levels of amyloid-beta and tau-positive neurofibrillary tangles and the presence
of Lewy bodies were quantified in six brain regions, and the number and location
of chronic cerebral infarctions were noted.
RESULTS: In analyses that controlled for age, sex, education, amyloid, tangles,
Lewy bodies, and cerebral infarction, higher level of chronic distress was
associated with a higher likelihood of dementia and lower level of cognition
proximate to death. Chronic distress was not correlated with any form of
neuropathology, including limbic, neocortical, and global indices, and did not
modify the association of pathology with cognition.
CONCLUSIONS: Chronic psychological distress is associated with late-life
dementia but not with its leading causes, suggesting that novel
neurodeteriorative mechanisms may be involved. BACKGROUND: There may be important public health implications of increasing our
knowledge of factors associated with age of dementia onset. The pre-morbid
personality domain of Neuroticism constituted an interesting and theoretically
plausible, yet uninvestigated, candidate for such an association. We aimed to
examine whether midlife Neuroticism was associated with earlier age of onset of
Alzheimer's disease (AD).
METHOD: This was a case-comparison study of 213 patients with probable AD.
Detailed clinical information was collected for all patients including age of
onset of dementia symptoms. One or two knowledgeable informants rated each
patient's midlife personality retrospectively using the Neuroticism,
Extraversion, Openness Five-Factor Inventory (NEO-FFI) questionnaire. The
relationship between midlife Neuroticism and age of dementia onset was evaluated
using both correlational analysis and backward linear regression analysis.
RESULTS: Midlife Neuroticism predicted younger age of dementia onset in females
but not in males. The association found in females was independent of pre-morbid
history of affective disorder.
CONCLUSIONS: This finding and its potential mechanism warrant further
investigation. OBJECTIVE: High neuroticism has been associated with a greater risk of dementia,
and an active/socially integrated lifestyle with a lower risk of dementia. The
aim of the current study was to explore the separate and combined effects of
neuroticism and extraversion on the risk of dementia, and to examine whether
lifestyle factors may modify this association.
METHODS: A population-based cohort of 506 older people with no dementia from the
Kungsholmen Project, Stockholm, Sweden, was followed up for an average of 6
years. Personality traits were assessed using the Eysenck Personality Inventory.
Dementia was diagnosed by specialists according to DSM-III-R criteria.
RESULTS: Neither high neuroticism nor low extraversion alone was related to
significantly higher incidence of dementia. However, among people with an
inactive or socially isolated lifestyle, low neuroticism was associated with a
decreased dementia risk (hazard ratio [HR] = 0.51, 95% confidence interval [CI]
= 0.27-0.96). When compared to persons with high neuroticism and high
extraversion, a decreased risk of dementia was detected in individuals with low
neuroticism and high extraversion (HR = 0.51, 95% CI = 0.28-0.94), but not among
persons with low neuroticism and low extraversion (HR = 0.95, 95% CI =
0.57-1.60), nor high neuroticism and low extraversion (HR = 0.97 95% CI =
0.57-1.65). Stratified analysis by lifestyle showed that the inverse association
of low neuroticism and high extraversion in combination was present only among
the inactive or socially isolated persons.
CONCLUSION: Low neuroticism in combination with high extraversion is the
personality trait associated with the lowest dementia risk; however, among
socially isolated individuals even low neuroticism alone seems to decrease
dementia risk. [Correction Notice: An erratum for this article was reported in Vol 26(2) of
Psychology and Aging (see record 2011-05802-001). This article contains an error
in the Discussion, under the Implications, Caveats, Future Directions heading.
The third paragraph includes the sentences that should have been removed. The
corrected paragraph appears in the correction.] We conducted secondary analyses
to determine the relationship between longstanding personality traits and risk
for Alzheimer's disease (AD) among 767 participants 72 years of age or older who
were followed for more than 6 years. Personality was assessed with the NEO-FFI.
We hypothesized that elevated Neuroticism, lower Openness, and lower
Conscientiousness would be independently associated with risk of AD. Hypotheses
were supported. The finding that AD risk is associated with elevated Neuroticism
and lower Conscientiousness can be added to the accumulating literature
documenting the pathogenic effects of these two traits. The link between lower
Openness and AD risk is consistent with recent findings on cognitive activity
and AD risk. Findings have implications for prevention research and for the
conceptualization of the etiology of AD. OBJECTIVE: To identify the components of the neuroticism trait most responsible
for its association with cognitive decline and dementia in old age.
DESIGN: Longitudinal clinical-pathologic cohort study.
SETTING: Chicago metropolitan area.
PARTICIPANTS: A total of 785 older persons without dementia completed standard
self-report measures of six components of neuroticism and then had annual
clinical evaluations for a mean of 3.4 years and brain autopsy in the event of
death.
MEASUREMENTS: Incidence of clinically diagnosed Alzheimer disease (AD), change
in global and specific cognitive functions, and postmortem measures of plaques
and tangles, cerebral infarction, and Lewy bodies.
RESULTS: During follow-up, 94 individuals developed AD. Higher levels of anxiety
and vulnerability to stress were associated with increased risk of AD and more
rapid decline in global cognition, with no effects for the other four trait
components. In analyses of specific cognitive systems, neuroticism subscales
were related to decline in episodic memory, working memory, and perceptual
speed, but not in semantic memory or visuospatial ability. No component of
neuroticism was related to the neuropathologic lesions most commonly associated
with late-life dementia.
CONCLUSIONS: Neuroticism's association with late-life dementia mainly reflects
vulnerability to stress and anxiety and their correlation with decline in the
ability to process and retain new information. OBJECTIVE: To investigate personality traits in patients with Alzheimer disease,
compared with mentally healthy control subjects. We compared both current
personality characteristics using structured interviews as well as current and
previous personality traits as assessed by proxies.
METHOD: Fifty-four patients with mild Alzheimer disease and 64 control subjects
described their personality traits using the Structured Interview for the
Five-Factor Model. Family members filled in the Revised NEO Personality
Inventory, Form R, to evaluate their proxies' current personality traits,
compared with 5 years before the estimated beginning of Alzheimer disease or 5
years before the control subjects.
RESULTS: After controlling for age, the Alzheimer disease group presented
significantly higher scores than normal control subjects on current neuroticism,
and significantly lower scores on current extraversion, openness, and
conscientiousness, while no significant difference was observed on
agreeableness. A similar profile, though less accentuated, was observed when
considering personality traits as the patients' proxies remembered them.
Diachronic personality assessment showed again significant differences between
the 2 groups for the same 4 domains, with important personality changes only for
the Alzheimer disease group.
CONCLUSIONS: Group comparison and retrospective personality evaluation are
convergent. Significant personality changes follow a specific trend in patients
with Alzheimer disease and contrast with the stability generally observed in
mentally healthy people in their personality profile throughout their lives.
Whether or not the personality assessment 5 years before the current status
corresponds to an early sign of Alzheimer disease or real premorbid personality
differences in people who later develop Alzheimer disease requires longitudinal
studies. OBJECTIVE: People with Alzheimer's disease (AD) commonly exhibit changes in
personality that sometimes precede the other early clinical manifestations of
the condition, such as cognitive impairment and mood changes. Although these
personality changes reflect the impact of progressive brain damage, there are
several possible patterns of personality change with dementia. Early
identification of personality change might assist with the timely diagnosis of
AD. The objective of this study was to review studies of personality change in
AD.
METHODS: Systematic searches of the PubMed, Ovid Medline, EBSCOhost, PsychINFO
and CINAHL databases were undertaken from inception to November 2009. Published
studies of informant-rated personality traits in AD patients were identified.
Studies that mapped changes in traits from the five-factor model of personality
which includes factors for Neuroticism, Extraversion, Openness, Agreeableness
and Conscientiousness, were selected for analysis. The change in each of these
five traits was calculated as the mean difference in score before and after the
diagnosis of AD.
RESULTS: There was a mean increase in Neuroticism of 10-20 T scores (equivalent
to 1-2 SD), a decrease of the same magnitude in Extraversion, consistently
reduced Openness and Agreeableness, and a marked decrease in Conscientiousness
of about 20-30 T scores (equivalent to 2-3 SD). These changes were systematic
and consistent. Particularly striking was the similarity of both the magnitude
and direction of change in all studies reviewed.
CONCLUSIONS: Conscientiousness and Neuroticism are the personality traits that
exhibit the most change in dementia. These traits might be useful early markers
of dementia. We examined the association of social activity with cognitive decline in 1138
persons without dementia at baseline with a mean age of 79.6 (SD = 7.5) who were
followed for up to 12 years (mean = 5.2; SD = 2.8). Using mixed models adjusted
for age, sex, education, race, social network size, depression, chronic
conditions, disability, neuroticism, extraversion, cognitive activity, and
physical activity, more social activity was associated with less cognitive
decline during average follow-up of 5.2 years (SD = 2.7). A one point increase
in social activity score (range = 1-4.2; mean = 2.6; SD = 0.6) was associated
with a 47% decrease in the rate of decline in global cognitive function (p <
.001). The rate of global cognitive decline was reduced by an average of 70% in
persons who were frequently socially active (score = 3.33, 90th percentile)
compared to persons who were infrequently socially active (score = 1.83, 10th
percentile). This association was similar across five domains of cognitive
function. Sensitivity analyses revealed that individuals with the lowest levels
of cognition or with mild cognitive impairment at baseline did not drive this
relationship. These results confirm that more socially active older adults
experience less cognitive decline in old age. OBJECTIVES: We tested the hypothesis that neuroticism moderates the association
between APOE (apolipoprotein E) genotype and two major outcomes, cognitive
function and Alzheimer disease. We also explored whether other personality
dimensions (extraversion, openness to experience, agreeableness, and
conscientiousness) moderate the associations of APOE with these outcomes.
DESIGN: Primary analyses of existing randomized clinical trial data.
SAMPLE: Six-hundred two older adults (mean age of 78 years at baseline).
MEASUREMENTS: APOE genotype, the NEO-Five Factor Inventory, the Alzheimer's
Disease Assessment Scale-Cognitive: measured every 6 months for 6.5 years) and
relevant covariates.
RESULTS: Fully adjusted multivariate analyses showed that the association
between the presence of APOE [Latin Small Letter Open E]-4 allele(s) and both
outcomes was evident among individuals with high levels of neuroticism and
extraversion but not among persons with low levels of these traits.
CONCLUSIONS: Phenotypic personality dimensions, primarily neuroticism and
extraversion, moderate the relationship between APOE [Latin Small Letter Open
E]-4 genotype and cognitive outcomes among older adults. Future research is
needed to elucidate the physiological processes involved in these particular
phenotype-genotype interactions. |
What is the mode of action of everolimus? | Everolimus is a drug that binds to mTORC1 and inhibits activation of the mTOR signalling pathway. It is used in targeted cancer therapy protocols or after transplantation for maintenance immunosuppression, against allograft rejection. | BACKGROUND: Target of rapamycin inhibitors (TOR-I) have a novel mode of action
but uncertain clinical role. We performed a systematic review of randomized
trials where immunosuppressive regimens containing TOR-I were compared with
other regimens as initial therapy for kidney transplant recipients.
METHODS: Databases (inception, June 2005) and conference proceedings (1996-2005)
were searched. Two independent reviewers assessed trials for eligibility and
quality. Results at 1 year, are expressed as relative risk (RR), where values<1
favor TOR-I, or lower dose of TOR-I, and for continuous outcomes are expressed
as weighted mean difference (WMD), both expressed with 95% confidence intervals
(CI).
RESULTS: Thirty-three trials (142 reports) were included (27 trials of
sirolimus, 5 of everolimus, and 1 of head-to-head comparison). When TOR-I
replaced calcineurin inhibitors (CNI) (8 trials with 750 participants), there
was no difference in acute rejection (RR, 1.03; 95% CI, 0.74-1.44), but serum
creatinine was lower (WMD, -18.31 micromol/L; 95% CI, -30.96 to -5.67) and bone
marrow more suppressed (leukopenia: RR 2.02; 95% CI, 1.12-3.66;
thrombocytopenia: RR, 6.97; 95% CI, 2.97-16.36; and anaemia: RR, 1.67; 95% CI,
1.27-2.20). When TOR-I replaced antimetabolites (11 trials with 3966
participants), acute rejection and cytomegalovirus infection (CMV) were reduced
(RR, 0.84; 95% CI, 0.71-0.99; RR, 0.49; 95% CI, 0.37-0.65, respectively), but
hypercholesterolemia was increased (RR, 1.65; 95% CI, 1.32-2.06). When low- was
compared with high-dose TOR-I, with equal CNI dose (10 trials with 3,175
participants), rejection was increased (RR, 1.23; 95% CI, 1.06-1.43) but
calculated glomerular filtration rate (GFR) higher (WMD, 4.27 mL/min; 95% CI,
1.12-7.41), and when lower-dose TOR-I and standard-dose CNI were compared with
higher-dose TOR-I and reduced CNI, acute rejection was reduced (RR, 0.67; 95%
CI, 0.52-0.88), but calculated GFR was also reduced (WMD, -9.46 mL/min; 95% CI,
-12.16 to -6.76). There was no significant difference in mortality, graft loss,
or maligcy risk for TOR-I in any comparison.
CONCLUSIONS: TOR-I have been evaluated in four different primary
immunosuppressive algorithms: as replacement for CNI and antimetabolites, in
combination with CNI at low and high doses, and with a variable dose of CNI.
Generally, surrogate endpoints for graft survival favor TOR-I (lower risk of
acute rejection and higher GFR), and surrogate endpoints for patient outcomes
are worsened by TOR-I (bone marrow suppression and lipid disturbance). Long-term
hard-endpoint data from methodologically robust randomized trials are still
required. Acute rejection episodes are now as low as 5-20% in the first year after renal
transplantation; however, graft half-life has remained almost unchanged in the
last decade. This statistic is mainly attributable to the side effects of
immunosuppression, with loss of allografts due to the chronic allograft
nephropathy that is a consequence of calcineurin inhibitor toxicity or
hypertension. Patient death due to cardiovascular events, infections and
maligcy also contribute to allograft loss. The introduction of the inhibitors
of the mammalian target of rapamycin sirolimus and everolimus in renal
transplantation has increased the repertoire of immunosuppressive protocols
substantially. They have a different mode of action and a different side effect
profile (i.e. lower nephrotoxicity, less hypertension and less neoplastic
potential) than the calcineurin inhibitors. The inhibitors of the mammalian
target of rapamycin therefore provide an especially promising alternative for
the maintece immunosuppression after renal transplantation. This overview
provides a summary of the current literature on inhibitors of the mammalian
target of rapamycin, with a special focus on sirolimus. BACKGROUND/AIM: The mode of action of the somatostatin analog octreotide on
neuro-endocrine tumour proliferation is largely unknown. Overexpression of the
proto-oncogene Akt/PKB (protein kinase B) has been demonstrated in certain
neuro-endocrine tumours: Akt activates downstream proteins including mTOR and
p70S6K, which play an important role in cell proliferation. RAD001 (everolimus)
is a novel agent that is being trialled in the treatment of neuro-endocrine
tumours, and is known to interact with mTOR. We explored the mechanism of action
of octreotide, RAD001, and their combination on cell proliferation and kinase
activation in a neuro-endocrine tumour cell line (rat insulinoma cell line,
INS1).
METHODS: Proliferation assays were used to determine the effects of octreotide,
RAD001, and their combination on cell proliferation. Western blotting was used
to characterize the expression of phosphorylated Akt, phosphorylated TSC2,
phosphorylated mTOR, and phosphorylated 70S6K.
RESULTS: Treatment with octreotide and RAD001 inhibited proliferation and
attenuated phosphorylation of all downstream targets of Akt: TSC2, mTOR, and
p70S6K.
CONCLUSIONS: In this cell model, octreotide and RAD001 appear to act through a
similar pathway and inhibit the Akt-mTOR-p70S6 kinase pathway downstream of Akt.
There may be some overlapping effects of the two inhibitors on the mTOR pathway,
although it is likely that other additional effects may differentiate the two
agents. Targeted therapies are widely used in cancer because of their effectiveness,
even in tumours that are resistant to conventional chemotherapy such as kidney
or hepatocellular carcinomas. There are different families classified according
to their mode of action. The antiangiogenics block tumor angiogenesis by acting
on VEGF or its receptor. The main molecules are bevacizumab, sunitinib, and
sorafinib. HER inhibitors work by blocking these receptors, which control
different signaling intracellular pathways, and include an inhibitor of HER2,
trastuzumab, and various inhibitors of HER1, or EGFR, including cetuximab,
erlotinib, and gefitinib. Inhibitors of KIT, a membrane receptor, are mainly
represented by imatinib, an inhibitor of tyrosine kinase. Finally, mTOR
inhibitors act on the signaling pathway PI3K/AKT/mTOR, and key molecules are
temsirolimus, everolimus, and deforolimus. The mammalian target of rapamycin(mTOR)and its molecular pathways are supposed
to be activated frequently in human renal cell carcinoma as well as other
cancers. It has a kinase activity for 40S ribosomal protein kinase and
eukaryotic translation initiation factor 4E-binding protein 1. These proteins,
when phosphorylated, promote protein translation and RNA transcription in the
nutrient-rich condition. mTOR inhibitors such as Temsirolimus (CCI779) and
Everolimus (RAD001) are effective for suppressing cell growth with inhibiting
mTOR kinase activity. Rapamycin and its related analogs such as Temsirolimus and
Everolimus are less toxic for humans compared with other anti-VEGFR inhibitors
and has been used as an immunosuppressive agent. These agents have an inhibitory
activity against the mTORC1 complex. Since they do not have inhibitory activity
against mTORC2 complex, the ability of mTOR inhibition by Temsirolimus is
supposed to be 40 to 50% of full inhibition in mTOR kinase. Temsirolimus has
modest anticancer activity against advanced clinical RCC patients with poor
risk. The objective response rate was only 7%, 26% of patients experienced minor
responses and another 17% of patients had stable disease that lasted 6 months.
The median time to tumor progression and median survival for the study patients
were 5.8 and 15.0 months, respectively. The overall survival of patients treated
with Temsirolimus alone was statistically longer than in those treated with IFN
alone in the 626 cases in phase II study. Combinations of mTOR with other anti-
VEGFR agents were not effective. Vertical therapies of mTOR inhibitor in
combination with AKT inhibitors, or newly development of stronger mTOR kinase
which can suppress both mTORC1 and mTORC2 are planned at present. Mammalian target of rapamycin (mTOR) is a key protein kinase controlling signal
transduction from various growth factors and upstream proteins to the level of
mRNA translation and ribosome biogenesis, with pivotal regulatory effects on
cell cycle progression, cellular proliferation and growth, autophagy and
angiogenesis. The mTOR pathway, and its upstream regulators in the PI3K/PTEN/AKT
cascade, are altered in a variety of experimental and human maligcies.This
has led to the prediction that mTOR inhibitors may be used as anticancer agents.
With the recent approval of two mTOR-targeted drugs (temsirolimus and
everolimus) for the treatment of renal cell carcinoma and mantle cell lymphoma,
this paradigm has been effectively translated into the clinical setting. In this
review, we discuss mTOR biology and regulation, the mode of action of mTOR
inhibitors as anti-cancer agents, and current clinical evidence supporting the
use of rapamycin-like mTOR inhibitors in cancer treatment. Sorafenib and sunitinib are inhibitors of receptor protein tyrosine kinases
(TKIs) and are approved for the treatment of metastatic renal cell carcinoma
(mRCC). Although the mTOR inhibitor everolimus is effective for the treatment of
patients who have failed TKI therapy, it is important to consider all available
treatment options before switching therapy mode of action. Herein, we report
outcomes in patients with mRCC switched to sorafenib following disease
progression on sunitinib treatment. The medical records of 35 patients treated
between November 2006 and November 2009 at two large referral centers in Greece
were retrospectively analyzed for time-to-progression (TTP), overall survival
(OS), and tolerability of sorafenib after sunitinib. Median TTP and OS on
sorafenib were 4.9 and 11.5 months, respectively. Among 33 patients evaluable
for tumor response, three had a partial response and 17 achieved disease
stabilization (objective response rate 8.5%; total clinical benefit rate 57%).
Sorafenib was well tolerated, with mostly grade 1/2 adverse events and no
treatment-related deaths. Sorafenib was effective and well tolerated in this
group of patients. The TTP with sorafenib following sunitinib was comparable to
outcomes reported previously, providing further support that TKIs should be used
in sequence before switching to an mTOR inhibitor. AIM: To describe drugs used in renal cell carcinoma.
METHOD: Pubmed search for efficacy, mode of action and side effects for each
molecule. Additional data were searched from the French regulatory agencies
websites (HAS and ANSM).
RESULTS: Since 2007, a total of three different therapeutic classes in the
management of metastatic renal cell carcinoma are available. These three classes
are tyrosine kinase inhibitors with sunitinib and sorafenib, the anti-VEGF
antibodies (bevacizumab which is associated with alpha interferon in the
treatment of advanced kidney cancer) and mTOR inhibitors with temsirolimus and
everolimus. These targeted therapies are a major progress in the treatment of
patients with metastatic kidney cancer. The side effects encountered with these
molecules are numerous but serious side effects are less than 5% of all reported
side effects.
CONCLUSIONS: A better understanding of molecular mechanisms has enabled the
development of new therapies for the treatment of metastatic renal cell
carcinoma. In the future, a personalized approach taking into account the
biology of each tumor could be created to provide a more targeted treatment. |
Have Quantitative Trait Loci affecting splicing (splicing QTLs) been linked to disease? | Yes, mutations in the DNA that affect the splicing pattern of genes have been linked in transcriptome population studies to a number of diseases. | BACKGROUND: To elucidate mechanisms involved in multiple sclerosis (MS), we
studied genetic regulation of experimental autoimmune encephalomyelitis (EAE) in
rats, assuming a conservation of pathogenic pathways. In this study, we focused
on Eae23, originally identified to regulate EAE in a (LEW.1AV1xPVG.1AV1)F2
cross. Our aim was to determine whether one or more genes within the 67 Mb
region regulate EAE and to define candidate risk genes.
METHODOLOGY/PRINCIPAL FINDINGS: We used high resolution quantitative trait loci
(QTL) analysis in the 10th generation (G10) of an advanced intercross line (AIL)
to resolve Eae23 into two QTLs that independently regulate EAE, namely Eae23a
and Eae23b. We established a congenic strain to validate the effect of this
region on disease. PVG alleles in Eae23 resulted in significant protection from
EAE and attenuated CNS inflammation/demyelination. Disease amelioration was
accompanied with increased levels of Foxp3(+) cells in the CNS of the congenic
strain compared to DA. We then focused on candidate gene investigation in
Eae23b, a 9 Mb region linked to all clinical phenotypes. Affymetrix exon arrays
were used to study expression of the genes in Eae23b in the parental strains,
where none showed differential expression. However, we found lower expression of
exon 4 of ZEB1, which is specific for splice-variant Zfhep1. ZEB1 is an
interleukin 2 (IL2) repressor involved in T cell development. The
splice-specific variance prompted us to next analyze the expression of ZEB1 and
its two splice variants, Zfhep1 and Zfhep2, in both lymph node and spleen. We
demonstrated that ZEB1 splice-variants are differentially expressed; severity of
EAE and higher IL2 levels were associated with down-regulation of Zfhep1 and
up-regulation of Zfhep2.
CONCLUSIONS/SIGNIFICANCE: We speculate that the balance between splice-variants
of ZEB1 could influence the regulation of EAE. Further functional studies of
ZEB1 and the splice-variants may unravel novel pathways contributing to MS
pathogenesis and inflammation in general. The spontaneously hypertensive rat (SHR) is a widely used rodent model of
hypertension and metabolic syndrome. Previously we identified thousands of
cis-regulated expression quantitative trait loci (eQTLs) across multiple tissues
using a panel of rat recombit inbred (RI) strains derived from Brown Norway
and SHR progenitors. These cis-eQTLs represent potential susceptibility loci
underlying physiological and pathophysiological traits manifested in SHR. We
have prioritized 60 cis-eQTLs and confirmed differential expression between the
parental strains by quantitative PCR in 43 (72%) of the eQTL transcripts.
Quantitative trait transcript (QTT) analysis in the RI strains showed highly
significant correlation between cis-eQTL transcript abundance and clinically
relevant traits such as systolic blood pressure and blood glucose, with the
physical location of a subset of the cis-eQTLs colocalizing with "physiological"
QTLs (pQTLs) for these same traits. These colocalizing correlated cis-eQTLs
(c3-eQTLs) are highly attractive as primary susceptibility loci for the
colocalizing pQTLs. Furthermore, sequence analysis of the c3-eQTL genes
identified single nucleotide polymorphisms (SNPs) that are predicted to affect
transcription factor binding affinity, splicing and protein function. These
SNPs, which potentially alter transcript abundance and stability, represent
strong candidate factors underlying not just eQTL expression phenotypes, but
also the correlated metabolic and physiological traits. In conclusion, by
integration of genomic sequence, eQTL and QTT datasets we have identified
several genes that are strong positional candidates for pathophysiological
traits observed in the SHR strain. These findings provide a basis for the
functional testing and ultimate elucidation of the molecular basis of these
metabolic and cardiovascular phenotypes. |
Which technique is used for detection of EWS/FLI1 fusion transcripts? | Molecular detection of EWS-FLI1 chimeric transcripts in Ewing family tumors is carried out by reverse transcription-polymerase chain reaction (RT-PCR). | The t(11.22)(q24.q12) results in expression of a chimeric RNA product, EWS-FLI1.
This RNA product is expressed in over 85% of tumours belonging to the Ewing's
family, and is increasingly used as a definitive characteristic of these
tumours. In this study, we evaluated reverse transcriptase-polymerase chain
(RT-PCR) for EWS-FLI1 fusion transcripts in 18 neurally derived small round cell
tumours. These included six Ewing's family tumours and 12 neuroblastomas.
EWS-FLI1 fusion transcripts were identified in all six Ewing's tumours, but also
in two of the 12 neuroblastomas. One neuroblastoma contained the classic type 1
fusion transcript, and the second a type 1 transcript containing a 66 bp (base
pair) insert that was not derived from the EWS or FLI1 gene. The presence of
EWS-FLI1 fusion products in RNA extracted from primary neuroblastoma suggests
the identification of EWS-FLI1 fusion transcripts is not pathognomonic for
tumours of the Ewing's family. The clinical significance of these fusion
transcripts in neuroblastoma is not known. Chromosomal translocations generating unique chimeric genes are highly
characteristic of specific sarcomas, and their use as diagnostic markers has
been suggested. From a diagnostic pathologic point of view, detection of such
cytogenetic or molecular aberrations applicable to routinely processed archival
tissue specimens is considered a powerful tool for tumor diagnosis. To assess
the feasibility and reliability of the molecular detection of the transcript
originating from the chimeric gene in paraffin-embedded tumor specimens, we
performed a nested reverse transcription-polymerase chain reaction
(RT-PCR)-based assay to detect the EWS-FLI1 chimeric message in a series of
Ewing family tumors. Of 24 paraffin-embedded tumor specimens from 23 cases
analyzed, the chimeric message was detectable in 20 (83%) specimens from 20
cases (87%) by this nested RT-PCR assay, whereas none of 7 small round cell
tumors not from this family (3 alveolar rhabdomyosarcomas, 2 neuroblastomas, 2
maligt lymphomas) showed detectable chimeric messages. In the sequence
analysis of the PCR products, the amplified chimeric messages contained the
junctions between exon 7 of the EWS gene and any one of exons 5, 6 and 8 of the
FLI1 gene. The detection process was usually completed within 3 days, except for
the subseqent sequence analysis. Our results endorse the use of this molecular
assay as an ancillary technique in the diagnosis of Ewing family tumors using
paraffin-embedded material. OBJECTIVE: To investigate the expression of EWS-FLI1/ERG fusion transcript
resulting from t(11;12)(q24;12) in paraffin-embedded tissues and its diagnostic
implication for Ewing's sarcoma/peripheral primitive neuroectodermal tumors
(ES/pPNET).
METHODS: One-step reverse transcriptase-polymerase chain reaction (RT-PCR) was
employed to detect a characteristic EWS-FLI1/ERG fusion transcript in 25 cases
of ES/pPNET and 15 cases of other small round cell tumors (including 8 cases of
rhabdomyosarcoma, 4 cases of synovial sarcoma, 2 cases of neuroblastoma and 1
case of lymphoma) using formalin-fixed and paraffin-embedded tissues.
RESULTS: EWS-FLI1/ERG fusion transcript was detected in 20 of the 25 ES/pPNET
cases (80%). The 15 non-ES/pPNET control cases were negative for EWS-FLI1/ERG
fusion transcript.
CONCLUSIONS: Detection of EWS-FLI1/ERG fusion transcript is a reliable index for
molecular diagnosis of ES/pPNET. One-step RT-PCR is a practical method for such
analysis in routine paraffin-embedded tumor tissues. BACKGROUND: Ewing's sarcoma/peripheral primitive neuroectodermal tumor
(ES/pPNET) is often difficult to distinguish from other small round cell tumors.
The EWS-Ets gene fusions that result from chromosomal translocations in this
tumor provide potential molecular diagnostic markers. To apply these molecular
markers to commonly available archival materials, we evaluated the feasibility
of detecting EWS-Ets including EWS-Fli1 and EWS-ERG fusion transcripts in
paraffin-embedded tissues and its diagnostic value for detecting ES/pPNET.
METHODS: Thirteen paraffin-embedded samples of ES/pPNETs were retrieved from
archives. Thirteen cases of other tumors with small round cell features
(including rhabdomyosarcoma, neuroblastoma, lymphoma, small cell carcinoma, and
desmoplastic small round cell tumor) were used as negative controls. Beta-actin
and beta2-microglobulin were used as internal controls. A nested reverse
transcriptase-polymerase chain reaction (RT-PCR)-based assay was performed to
detect the EWS-Fli1 and EWS-ERG fusion transcripts.
RESULTS: Beta-actin and beta2-microglobulin were detected in 10/13 and 13/13
ES/pPNETs, respectively. EWS-Fli1 fusion transcripts were detected in 11 of 13
(85%) ES/pPNETs. Three chimeric transcripts, all EWS-Fli1, were detected in
ES/pPNET samples. Among 11 EWS-Fli1-positive cases, 7 cases had a type I fusion
transcript involving fusion of EWS exon 7 with Fli1 exon 6, 2 cases had a type
II fusion transcript involving EWS exon 7 with Fli1 exon 5, and 2 cases
expressed fusion transcripts involving EWS exon 7 and Fli1 exon 8. Type I
EWS-Fli1 fusion predominated over other types. Fusion types could not be
distinguished in the remaining 2 cases. Thirteen negative controls did not show
detectable chimeric messages. There was a significant relationship between
EWS-Fli1 fusion transcripts and CD99 expression.
CONCLUSIONS: Molecular detection of EWS-Fli1 fusion transcripts in
formalin-fixed paraffin-embedded material by nested RT-PCR is feasible and is
useful for the diagnosis and differential diagnosis of ES/pPNETs. We evaluated the feasibility and usefulness of reverse transcriptase-polymerase
chain reaction (RT-PCR) on fine-needle aspirates for categorization of small
blue round cell tumors (SBRCTs). A total of 51 cases, including 25 Ewing
sarcoma/peripheral primitive neuroectodermal tumors (PNETs), 11
rhabdomyosarcomas, 13 neuroblastomas, and 2 desmoplastic small round cell tumors
(DSRCTs) were analyzed. The detection of the EWS-FLI1 (20/25) and EWS-ERG (4/25)
fusion transcripts resolved 24 of 25 cases of Ewing sarcoma/PNET. The
PAX3/7-FKHR fusion transcript was detected in 2 of 4 cases of alveolar
rhabdomyosarcoma and the EWS-WT1 transcript in both cases of DSRCT. Tyrosine
hydroxylase and 3,4-dihydroxyphenylalanine (dopa) decarboxylase transcripts were
demonstrated in 10 of 13 cases of neuroblastoma. In comparison,
immunocytochemical analysis resolved 19 (76%) of 25 Ewing sarcomas, 9 (82%) of
11 rhabdomyosarcomas, 6 (46%) of 13 neuroblastomas, and 1 (50%) of 2 DSRCTs.
Overall, RT-PCR resolved 38 (86%) of 44 vs 35 (69%) of 51 cases by
immunocytochemical analysis. RT-PCR is easily applied to fine-needle aspirates
of SBRCT and greatly facilitates accurate tumor typing. We report the case of a patient in whom the diagnosis of Ewing sarcoma arising
from a soft tissue was made after successful treatment of diffuse large B-cell
lymphoma. A 65-year-old woman presented with a rapidly growing mass in her left
scapular region 8 years after successful chemotherapy with the cyclophosphamide,
hydroxydaunomycin hydrochloride, vincristine, prednisolone regimen for diffuse
large B-cell lymphoma. Computed tomographic examination and magnetic resoce
imaging of the thorax revealed an intramuscular tumour measuring 40 mm in size
in the left scapular region. Histopathological examination of an open biopsy
specimen revealed a small round cell tumour that showed positive staining for
CD99. Fluorescence in situ hybridization showed a split signal by a break-apart
probe for the EWS gene in chromosome 22q12. Reverse transcriptase-polymerase
chain reaction confirmed the expression of EWS-FLI1 fusion transcripts. Based on
these findings, the patient was diagnosed as having secondary Ewing sarcoma.
Despite adjuvant chemotherapy, however, she died of pulmonary metastases 2 years
after the diagnosis of Ewing sarcoma. Therapy-related haematological
maligcies with balanced translocations have been reported previously. A
mechanism similar to that underlying the development of secondary maligcy
might explain the occurrence of this solid cancer. Over the years, a wide clinicopathological spectrum has been identified within
Ewing family of tumors (EFTs). As these tumors are chemosensitive, their correct
and timely identification is necessary. The aims of this study were (1) to
present the diverse clinicopathological and molecular profile of EFTs in our
settings, (2) to identify a pragmatic approach for diagnosing EFTs, especially
for application of ancillary techniques, namely RT-PCR for specific transcripts
(EWS-FLI1, EWS-ERG) and FISH for EWSR1 gene rearrangement, in certain cases and
(3) to show the utility of tissue microarray in establishing a new FISH test.
Fifty-eight EFTs were identified in 38 males and 20 females within an age-range
of 1-65 years (median, 16), mostly in lower extremities (14) (24.1 %).
Therapeutically, most patients underwent neoadjuvant chemotherapy with
subsequent surgery. Histopathologically, diagnosis of EFTs was initially offered
in 41/58 (70.6 %) tumors. On review, 59 % tumors showed diffuse pattern, while
41 % displayed rosettes. Immunohistochemically, tumor cells were mostly
diffusely positive for CD99 (48/52) (92.3 %); FLI-1 (17/18) (94.4 %); variably
for BCL2 (16/18) (88.8 %), synaptophysin (6/20) (35 %), S100-P (2/7) (28.5 %),
CD56 (2/5) (40 %), NSE (2/5) (40 %), calponin (3/4) (75 %), EMA (5/24) (20.8 %)
and CK (3/24) (12.5 %), the latter two mostly focally. Fifty five tumors were
EWS-FLI1 positive, while a single tumor was EWS-ERG positive. Sensitivity for
PCR was 61 %. EWSR1 rearrangement was detected by FISH in 12/13 Ewing
sarcomas/PNETs. Sensitivity for EWSR1 test was 92.3 % and specificity was 100 %.
Thirty-eight tumors, including 14 molecular confirmed EFTs and 21 other tumors
were tested for EWSR1 rearrangement. Among 21 unrelated tumors, EWSR1
rearrangement was detected in few myoepithelial tumors, occasional desmoplastic
small round cell tumor and an extraskeletal myxoid chondrosarcoma. Further, a
tissue microarray with a separate set of 8 EFTs, confirmed at another laboratory
was analysed for validation of EWSR1 rearrangement test. 23/28 (82.1 %) tissue
cores of the tissue microarray, stained by FISH were interpretable, including
EWSR1 rearrangement, detected in 20/28 tissue cores; not detected in 3 liver
cores and uninterpretable in 5 (17.8 %) cores. Classical EFTs can be diagnosed
with diffuse, membranous CD99 positivity, intranuclear FLI1 positivity and LCA
negativity in maligt round cells. In unconventional cases, it is
indispensable to reveal the concomitant fusion m-RNA by RT-PCR. In case of
negative molecular results, it is necessary to prove EWSR1 rearrangement by
FISH. These tests should be interpreted with clinicopathological correlation.
Tissue microarrays for FISH are useful during validation of a new test,
especially when sarcomas like EFTs show less genetic heterogeneity within tumor
cells. |
Does the CTCF protein co-localize with cohesin? | Recent genome-wide studies mapping the binding sites of CTCF and its interacting partner, cohesin, using chromatin immunoprecipitation coupled with deep sequencing (ChIP-seq) revealded that CTCF globally co-localizes with cohesin. | Cohesin is required to prevent premature dissociation of sister chromatids after
DNA replication. Although its role in chromatid cohesion is well established,
the functional significance of cohesin's association with interphase chromatin
is not clear. Using a quantitative proteomics approach, we show that the STAG1
(Scc3/SA1) subunit of cohesin interacts with the CCTC-binding factor CTCF bound
to the c-myc insulator element. Both allele-specific binding of CTCF and
Scc3/SA1 at the imprinted IGF2/H19 gene locus and our analyses of human DM1
alleles containing base substitutions at CTCF-binding motifs indicate that
cohesin recruitment to chromosomal sites depends on the presence of CTCF. A
large-scale genomic survey using ChIP-Chip demonstrates that Scc3/SA1 binding
strongly correlates with the CTCF-binding site distribution in chromosomal arms.
However, some chromosomal sites interact exclusively with CTCF, whereas others
interact with Scc3/SA1 only. Furthermore, immunofluorescence microscopy and
ChIP-Chip experiments demonstrate that CTCF associates with both centromeres and
chromosomal arms during metaphase. These results link cohesin to gene regulatory
functions and suggest an essential role for CTCF during sister chromatid
cohesion. These results have implications for the functional role of cohesin
subunits in the pathogenesis of Cornelia de Lange syndrome and Roberts
syndromes. The cohesin complex is best known for its role in sister chromatid cohesion.
Over the past few years, it has become apparent that cohesin also regulates gene
expression, but the mechanisms by which it does so are unknown. Recently, three
groups mapped numerous cohesin-binding sites in mammalian chromosomes and found
substantial overlap with the CCCTC-binding factor (CTCF).1-3 CTCF is an
insulator protein that blocks enhancer-promoter interactions, and the
investigators found that cohesin also contributes to this activity. Thus, these
studies demonstrate at least one mechanism by which cohesin can control gene
expression. The human interleukin-3 (IL-3) and granulocyte-macrophage
colony-stimulating-factor (GM-CSF, or CSF2) gene cluster arose by duplication of
an ancestral gene. Although just 10 kb apart and responsive to the same signals,
the IL-3 and GM-CSF genes are nevertheless regulated independently by separate,
tissue-specific enhancers. To understand the differential regulation of the IL-3
and GM-CSF genes we have investigated a cluster of three ubiquitous DNase
I-hypersensitive sites (DHSs) located between the two genes. We found that each
site contains a conserved CTCF consensus sequence, binds CTCF, and recruits the
cohesin subunit Rad21 in vivo. The positioning of these sites relative to the
IL-3 and GM-CSF genes and their respective enhancers is conserved between human
and mouse, suggesting a functional role in the organization of the locus. We
found that these sites effectively block functional interactions between the
GM-CSF enhancer and either the IL-3 or the GM-CSF promoter in reporter gene
assays. These data argue that the regulation of the IL-3 and the GM-CSF
promoters depends on the positions of their enhancers relative to the conserved
CTCF/cohesin-binding sites. We suggest that one important role of these sites is
to enable the independent regulation of the IL-3 and GM-CSF genes. Cohesin is a DNA-binding protein complex that is essential for sister chromatid
cohesion and facilitates the repair of damaged DNA. In addition, cohesin has
important roles in regulating gene expression, but the molecular mechanisms of
this function are poorly understood. Recent experiments have revealed that
cohesin binds to the same sites in mammalian genomes as the zinc finger
transcription factor CTCF. At a few loci CTCF has been shown to function as an
enhancer-blocking transcriptional insulator, and recent observations indicate
that this function depends on cohesin. Here we review what is known about the
roles of cohesin and CTCF in regulating gene expression in mammalian cells, and
we discuss how cohesin might mediate the insulator function of CTCF. CTCF sites are abundant in the genomes of diverse species but their function is
enigmatic. We used chromosome conformation capture to determine long-range
interactions among CTCF/cohesin sites over 2 Mb on human chromosome 11
encompassing the beta-globin locus and flanking olfactory receptor genes.
Although CTCF occupies these sites in both erythroid K562 cells and fibroblast
293T cells, the long-range interaction frequencies among the sites are highly
cell type specific, revealing a more densely clustered organization in the
absence of globin gene activity. Both CTCF and cohesins are required for the
cell-type-specific chromatin conformation. Furthermore, loss of the
organizational loops in K562 cells through reduction of CTCF with shRNA results
in acquisition of repressive histone marks in the globin locus and reduces
globin gene expression whereas silent flanking olfactory receptor genes are
unaffected. These results support a genome-wide role for CTCF/cohesin sites
through loop formation that both influences transcription and contributes to
cell-type-specific chromatin organization and function. The cohesin protein complex holds sister chromatids in dividing cells together
and is essential for chromosome segregation. Recently, cohesin has been
implicated in mediating transcriptional insulation, via its interactions with
CTCF. Here, we show in different cell types that cohesin functionally behaves as
a tissue-specific transcriptional regulator, independent of CTCF binding. By
performing matched genome-wide binding assays (ChIP-seq) in human breast cancer
cells (MCF-7), we discovered thousands of genomic sites that share cohesin and
estrogen receptor alpha (ER) yet lack CTCF binding. By use of human
hepatocellular carcinoma cells (HepG2), we found that liver-specific
transcription factors colocalize with cohesin independently of CTCF at
liver-specific targets that are distinct from those found in breast cancer
cells. Furthermore, estrogen-regulated genes are preferentially bound by both ER
and cohesin, and functionally, the silencing of cohesin caused aberrant re-entry
of breast cancer cells into cell cycle after hormone treatment. We combined
chromosomal interaction data in MCF-7 cells with our cohesin binding data to
show that cohesin is highly enriched at ER-bound regions that capture
inter-chromosomal loop anchors. Together, our data show that cohesin cobinds
across the genome with transcription factors independently of CTCF, plays a
functional role in estrogen-regulated transcription, and may help to mediate
tissue-specific transcriptional responses via long-range chromosomal
interactions. Cellular metabolism alters patterns of gene expression through a variety of
mechanisms, including alterations in histone modifications and transcription
factor activity. Nicotinamide adenine dinucleotide (NAD)-dependent proteins such
as poly(ADP ribose) polymerases (PARPs) and sirtuin deacetylases play important
roles in this regulation, thus NAD provides a crucial link between metabolism
and these cellular signaling processes. Here, we found that lowering NAD levels
in mouse primary cortical neurons led to decreased activity-dependent BDNF
expression. The altered BDNF transcription occurred independently of Sirt or
Parp activities; instead, low NAD levels promoted increased DNA methylation of
the activity-dependent BDNF promoter. Increased methylation at this promoter
triggered the dissociation of the insulator protein CTCF as well as the
accompanying cohesin from the BDNF locus. The loss of these proteins resulted in
histone acetylation and methylation changes at this locus consistent with
chromatin compaction and gene silencing. Because BDNF is critical for neuronal
function, these results suggest that age- or nutrition-associated declines in
NAD levels as well as deficits in cohesin function associated with disease
modulate BDNF expression and could contribute to cognitive impairment. Recent studies have shown that the protein CTCF, which plays an important role
in insulation and in large-scale organization of chromatin within the eukaryotic
nucleus, depends for both activities on recruitment of the cohesin complex. We
show here that the interaction of CTCF with the cohesin complex involves direct
contacts between the cohesin subunit SA2 and specific regions of the C-terminal
tail of CTCF. All other cohesin components are recruited through their
interaction with SA2. Expression in vivo of CTCF mutants lacking the C-terminal
domain, or with mutations at sites within it required for SA2 binding, disrupts
the normal expression profile of the imprinted genes IGF2-H19 and also results
in a loss of insulation activity. Taken together, our results demonstrate that
specific sites on the C terminus of CTCF are essential for cohesin binding and
insulator function. The only direct interaction between CTCF and cohesin
involves contact with SA2, which is external to the cohesin ring. This suggests
that in recruiting cohesin to CTCF, SA2 could bind first and the ring could
assemble subsequently. The cohesin complex holds sister chromatids together and is essential for
chromosome segregation. Recently, cohesins have been implicated in
transcriptional regulation and insulation through genome-wide colocalization
with the insulator protein CTCF, including involvement at the imprinted H19/Igf2
locus. CTCF binds to multiple imprinted loci and is required for proper
imprinted expression at the H19/Igf2 locus. Here we report that cohesins
colocalize with CTCF at two additional imprinted loci, the Dlk1-Dio3 and the
Kcnq1/Kcnq1ot1 loci. Similar to the H19/Igf2 locus, CTCF and cohesins
preferentially bind to the Gtl2 differentially methylated region (DMR) on the
unmethylated maternal allele. To determine the functional importance of the
binding of CTCF and cohesins at the three imprinted loci, CTCF and cohesins were
depleted in mouse embryonic fibroblast cells. The monoallelic expression of
imprinted genes at these three loci was maintained. However, mRNA levels for
these genes were typically increased; for H19 and Igf2 the increased level of
expression was independent of the CTCF-binding sites in the imprinting control
region. Results of these experiments demonstrate an unappreciated role for CTCF
and cohesins in the repression of imprinted genes in somatic cells. CCCTC-binding factor (CTCF) is a master organizer of genome spatial organization
and plays an important role in mediating extensive chromatin interactions.
Circular chromosome conformation capture (4C) is a high-throughput approach that
allows genome-wide screening for unknown potential interaction partners. Using a
conserved CTCF binding site on the Bcl11b locus as bait, an interaction partner
at the Arhgap6 locus on a different chromosome was identified by 4C. Additional
experiments verified that the interchromatin interaction between the Bcl11b and
Arhgap6 loci was cell-type specific, which was cooperatively mediated by CTCF
and cohesin. Functional analysis showed that the interchromatin interaction
partners were repressing regulatory elements. These results indicate that
interaction chromatin loops regulate the expression of the relevant genes. During the last decades our view of the genome organization has changed. We
moved from a linear view to a looped view of the genome. It is now well
established that inter- and intra-connections occur between chromosomes and play
a major role in gene regulations. These interconnections are mainly orchestrated
by the CTCF protein, which is also known as the "master weaver" of the genome.
Recent advances in sequencing and genome-wide studies revealed that CTCF binds
to DNA at thousands of sites within the human genome, providing the possibility
to form thousands of genomic connection hubs. Strikingly, two histone variants,
namely H2A.Z and H3.3, strongly co-localize at CTCF binding sites. In this
article, we will review the recent advances in CTCF biology and discuss the role
of histone variants H2A.Z and H3.3 at CTCF binding sites. The somatic recombination of lymphocyte antigen receptor loci is integral to
lymphocyte differentiation and adaptive immunity. Here we review the relation of
this highly choreographed process with the zinc finger protein CTCF and with
cohesin, a protein complex best known for its essential functions in
post-replicative DNA repair and chromosome segregation during the cell cycle. At
lymphocyte antigen receptor loci, CTCF and cohesin shape long-range interactions
and contribute to V(D)J recombination by facilitating lineage- and
developmental-stage-specific transcription and accessibility. Extraordinary single-cell diversity is generated in the vertebrate nervous
system by the combinatorial expression of the clustered protocadherin genes
(Pcdhα, -β, and -γ). This diversity is generated by a combination of stochastic
promoter choice and alternative pre-mRNA splicing. Here we show that both the
insulator-binding protein CTCF and the cohesin complex subunit Rad21 bind to two
highly conserved DNA sequences, the first within and the second downstream of
transcriptionally active Pcdhα promoters. Both CTCF and Rad21 bind to these
sites in vitro and in vivo, this binding directly correlates with alternative
isoform expression, and knocking down CTCF expression reduces alternative
isoform expression. Remarkably, a similarly spaced pair of CTCF/Rad21 binding
sites was identified within a distant enhancer element (HS5-1), which is
required for normal levels of alternative isoform expression. We also identify
an additional, unique regulatory role for cohesin, as Rad21 binds to another
enhancer (HS7) independently of CTCF, and knockdown of Rad21 reduces expression
of the constitutive, biallelically expressed Pcdhα isoforms αc1 and αc2. We
propose that CTCF and the cohesin complex initiate and maintain Pcdhα promoter
choice by mediating interactions between Pcdhα promoters and enhancers. Eukaryotic genomes are organized into higher order chromatin architectures by
protein-mediated long-range interactions in the nucleus. CCCTC-binding factor
(CTCF), a sequence-specific transcription factor, serves as a chromatin
organizer in building this complex chromatin structure by linking chromosomal
domains. Recent genome-wide studies mapping the binding sites of CTCF and its
interacting partner, cohesin, using chromatin immunoprecipitation coupled with
deep sequencing (ChIP-seq) revealded that CTCF globally co-localizes with
cohesin. This partnership between CTCF and cohesin is emerging as a novel and
perhaps pivotal aspect of gene regulatory mechanisms, in addition to playing a
role in the organization of higher order chromatin architecture. The contribution of human subtelomeric DNA and chromatin organization to
telomere integrity and chromosome end protection is not yet understood in
molecular detail. Here, we show by ChIP-Seq that most human subtelomeres contain
a CTCF- and cohesin-binding site within ∼1-2 kb of the TTAGGG repeat tract and
adjacent to a CpG-islands implicated in TERRA transcription control. ChIP-Seq
also revealed that RNA polymerase II (RNAPII) was enriched at sites adjacent to
the CTCF sites and extending towards the telomere repeat tracts. Mutation of
CTCF-binding sites in plasmid-borne promoters reduced transcriptional activity
in an orientation-dependent manner. Depletion of CTCF by shRNA led to a decrease
in TERRA transcription, and a loss of cohesin and RNAPII binding to the
subtelomeres. Depletion of either CTCF or cohesin subunit Rad21 caused
telomere-induced DNA damage foci (TIF) formation, and destabilized TRF1 and TRF2
binding to the TTAGGG proximal subtelomere DNA. These findings indicate that
CTCF and cohesin are integral components of most human subtelomeres, and
important for the regulation of TERRA transcription and telomere end protection. The closely linked human protocadherin (Pcdh) α, β, and γ gene clusters encode
53 distinct protein isoforms, which are expressed in a combinatorial manner to
generate enormous diversity on the surface of individual neurons. This diversity
is a consequence of stochastic promoter choice and alternative pre-mRNA
processing. Here, we show that Pcdhα promoter choice is achieved by DNA looping
between two downstream transcriptional enhancers and individual promoters
driving the expression of alternate Pcdhα isoforms. In addition, we show that
this DNA looping requires specific binding of the CTCF/cohesin complex to two
symmetrically aligned binding sites in both the transcriptionally active
promoters and in one of the enhancers. These findings have important
implications regarding enhancer/promoter interactions in the generation of
complex Pcdh cell surface codes for the establishment of neuronal identity and
self-avoidance in individual neurons. Current epigenomics approaches have facilitated the genome-wide identification
of regulatory elements based on chromatin features and transcriptional regulator
binding and have begun to map long-range interactions between regulatory
elements and their targets. Here, we focus on the emerging roles of CTCF and the
cohesin in coordinating long-range interactions between regulatory elements. We
discuss how species-specific transposable elements may influence such
interactions by remodeling the CTCF binding repertoire and suggest that
cohesin's association with enhancers, promoters, and sites defined by CTCF
binding has the potential to form developmentally regulated networks of
long-range interactions that reflect and promote cell-type-specific
transcriptional programs. DNA binding factors are essential for regulating gene expression. CTCF and
cohesin are DNA binding factors with central roles in chromatin organization and
gene expression. We determined the sites of CTCF and cohesin binding to DNA in
mouse brain, genome wide and in an allele-specific manner with high read-depth
ChIP-seq. By comparing our results with existing data for mouse liver and
embryonic stem (ES) cells, we investigated the tissue specificity of CTCF
binding sites. ES cells have fewer unique CTCF binding sites occupied than liver
and brain, consistent with a ground-state pattern of CTCF binding that is
elaborated during differentiation. CTCF binding sites without the canonical
consensus motif were highly tissue specific. In brain, a third of CTCF and
cohesin binding sites coincide, consistent with the potential for many
interactions between cohesin and CTCF but also many instances of independent
action. In the context of genomic imprinting, CTCF and/or cohesin bind to a
majority but not all differentially methylated regions, with preferential
binding to the unmethylated parental allele. Whether the parental
allele-specific methylation was established in the parental germlines or
post-fertilization in the embryo is not a determit in CTCF or cohesin
binding. These findings link CTCF and cohesin with the control regions of a
subset of imprinted genes, supporting the notion that imprinting control is
mechanistically diverse. BACKGROUND: Recent studies suggested that human/mammalian genomes are divided
into large, discrete domains that are units of chromosome organization. CTCF, a
CCCTC binding factor, has a diverse role in genome regulation including
transcriptional regulation, chromosome-boundary insulation, DNA replication, and
chromatin packaging. It remains unclear whether a subset of CTCF binding sites
plays a functional role in establishing/maintaining chromatin topological
domains.
RESULTS: We systematically analysed the genomic, transcriptomic and epigenetic
profiles of the CTCF binding sites in 56 human cell lines from ENCODE. We
identified ~24,000 CTCF sites (referred to as constitutive sites) that were
bound in more than 90% of the cell lines. Our analysis revealed: 1) constitutive
CTCF loci were located in constitutive open chromatin and often co-localized
with constitutive cohesin loci; 2) most constitutive CTCF loci were distant from
transcription start sites and lacked CpG islands but were enriched with the
full-spectrum CTCF motifs: a recently reported 33/34-mer and two other
potentially novel (22/26-mer); 3) more importantly, most constitutive CTCF loci
were present in CTCF-mediated chromatin interactions detected by ChIA-PET and
these pair-wise interactions occurred predomitly within, but not between,
topological domains identified by Hi-C.
CONCLUSIONS: Our results suggest that the constitutive CTCF sites may play a
role in organizing/maintaining the recently identified topological domains that
are common across most human cells. The chromatin regulatory factors CTCF and cohesin have been implicated in the
coordinated control of multiple gene loci in Epstein-Barr virus (EBV) latency.
We have found that CTCF and cohesin are highly enriched at the convergent and
partially overlapping transcripts for the LMP1 and LMP2A genes, but it is not
yet known how CTCF and cohesin may coordinately regulate these transcripts. We
now show that genetic disruption of this CTCF binding site (EBVΔCTCF166) leads
to a deregulation of LMP1, LMP2A, and LMP2B transcription in EBV-immortalized B
lymphocytes. EBVΔCTCF166 virus-immortalized primary B lymphocytes showed a
decrease in LMP1 and LMP2A mRNA and a corresponding increase in LMP2B mRNA. The
reduction of LMP1 and LMP2A correlated with a loss of euchromatic histone
modification H3K9ac and a corresponding increase in heterochromatic histone
modification H3K9me3 at the LMP2A promoter region in EBVΔCTCF166. Chromosome
conformation capture (3C) revealed that DNA loop formation with the origin of
plasmid replication (OriP) enhancer was eliminated in EBVΔCTCF166. We also
observed that the EBV episome copy number was elevated in EBVΔCTCF166 and that
this was not due to increased lytic cycle activity. These findings suggest that
a single CTCF binding site controls LMP2A and LMP1 promoter selection, chromatin
boundary function, DNA loop formation, and episome copy number control during
EBV latency. Runx1 is a transcription factor essential for definitive hematopoiesis. In all
vertebrates, the Runx1 gene is transcribed from two promoters: a proximal
promoter (P2), and a distal promoter (P1). We previously found that runx1
expression in a specific hematopoietic cell population in zebrafish embryos
depends on cohesin. Here we show that zebrafish runx1 is directly bound by
cohesin and CCCTC binding factor (CTCF) at the P1 and P2 promoters, and within
the intron between P1 and P2. Cohesin initiates expression of runx1 in the
posterior lateral mesoderm and influences promoter use, while CTCF represses its
expression in the newly emerging cells of the tail bud. The intronic binding
sites for cohesin and CTCF coincide with histone modifications that confer
enhancer-like properties, and two of the cohesin/CTCF sites behaved as
insulators in an in vivo assay. The identified cohesin and CTCF binding sites
are likely to be cis-regulatory elements (CREs) for runx1 since they also
recruit RNA polymerase II (RNAPII). CTCF depletion excluded RNAPII from two
intronic CREs but not the promoters of runx1. We propose that cohesin and CTCF
have distinct functions in the regulation of runx1 during zebrafish
embryogenesis, and that these regulatory functions are likely to involve runx1
intronic CREs. Cohesin (but not CTCF) depletion enhanced RUNX1 expression in a
human leukemia cell line, suggesting conservation of RUNX1 regulation through
evolution. |
What is the application of the Bimolecular Fluorescence Complementation (BiFC) assay in Drosophila embryos? | Bimolecular fluorescence complementation (BiFC) is a powerful method for studying protein-protein interactions in different cell types and organisms. This method was recently developed in the fruit fly Drosophila melanogaster, allowing analyzing protein interaction properties in a physiologically relevant developing context. | Protein-protein interactions play a pivotal role in coordinating many cellular
processes. Determination of subcellular localization of interacting proteins and
visualization of dynamic interactions in living cells are crucial to elucidate
cellular functions of proteins. Using fluorescent proteins, we previously
developed a bimolecular fluorescence complementation (BiFC) assay and a
multicolor BiFC assay to visualize protein-protein interactions in living cells.
However, the sensitivity of chromophore maturation of enhanced yellow
fluorescent protein (YFP) to higher temperatures requires preincubation at lower
temperatures prior to visualizing the BiFC signal. This could potentially limit
their applications for the study of many signaling molecules. Here we report the
identification of new fluorescent protein fragments derived from Venus and
Cerulean for BiFC and multicolor BiFC assays under physiological culture
conditions. More importantly, the newly identified combinations exhibit a
13-fold higher BiFC efficiency than originally identified fragments derived from
YFP. Furthermore, the use of new combinations reduces the amount of plasmid
required for transfection and shortens the incubation time, leading to a 2-fold
increase in specific BiFC signals. These newly identified fluorescent protein
fragments will facilitate the study of protein-protein interactions in living
cells and whole animals under physiological conditions. A variety of experimental methods have been developed for the analysis of
protein interactions. The majority of these methods either require disruption of
the cells to detect molecular interactions or rely on indirect detection of the
protein interaction. The bimolecular fluorescence complementation (BiFC) assay
provides a direct approach for the visualization of molecular interactions in
living cells and organisms. The BiFC approach is based on the facilitated
association between two fragments of a fluorescent protein when the fragments
are brought together by an interaction between proteins fused to the fragments.
The BiFC approach has been used for visualization of interactions among a
variety of structurally diverse interaction partners in many different cell
types. It enables detection of transient complexes as well as complexes formed
by a subpopulation of the interaction partners. It is essential to include
negative controls in each experiment in which the interface between the
interaction partners has been mutated or deleted. The BiFC assay has been
adapted for simultaneous visualization of multiple protein complexes in the same
cell and the competition for shared interaction partners. A ubiquitin-mediated
fluorescence complementation assay has also been developed for visualization of
the covalent modification of proteins by ubiquitin family peptides. These
fluorescence complementation assays have a great potential to illuminate a
variety of biological interactions in the future. BACKGROUND: Protein interactions control the regulatory networks underlying
developmental processes. The understanding of developmental complexity will,
therefore, require the characterization of protein interactions within their
proper environment. The bimolecular fluorescence complementation (BiFC)
technology offers this possibility as it enables the direct visualization of
protein interactions in living cells. However, its potential has rarely been
applied in embryos of animal model organisms and was only performed under
transient protein expression levels.
RESULTS: Using a Hox protein partnership as a test case, we investigated the
suitability of BiFC for the study of protein interactions in the living
Drosophila embryo. Importantly, all BiFC parameters were established with
constructs that were stably expressed under the control of endogenous promoters.
Under these physiological conditions, we showed that BiFC is specific and
sensitive enough to analyse dynamic protein interactions. We next used BiFC in a
candidate interaction screen, which led to the identification of several Hox
protein partners.
CONCLUSION: Our results establish the general suitability of BiFC for revealing
and studying protein interactions in their physiological context during the
rapid course of Drosophila embryonic development. |
Which pathological condition of the heart is known as hypertrophic cardiomyopathy (HCM)? | Hypertrophic cardiomyopathy (HCM) has been recently recognized as the most common inherited cardiovascular disorder, affecting 1 in 500 adults worldwide. HCM is characterized by myocyte hypertrophy resulting in thickening of the ventricular wall, myocyte disarray, interstitial and/or replacement fibrosis, decreased ventricular cavity volume and diastolic dysfunction. HCM is also the most common cause of sudden death in the young particularly among athletes. A large proportion of patients diagnosed with HCM have mutations in sarcomeric proteins. HCM is the most prevalent genetic disorder affecting the heart and is typically inherited in an autosomal dominant pattern. Adults with cardiomyopathy suffer SCD or adverse events such as stroke and heart failure from HCM. | Hypertrophic cardiomyopathy (HCM) is a clinically heterogeneous autosomal
domit heart disease characterised by left ventricular hypertrophy in the
absence of another cardiac or systemic disease that is capable of producing
significant wall thickening. Microscopically it is characterised by
cardiomyocyte hypertrophy, myofibrillar disarray and fibrosis. The phenotypic
expression of HCM is multifactorial, with the majority of cases occurring
secondary to mutations in genes encoding the sarcomere proteins. In conjunction
with the genetic heterogeneity of HCM, phenotypic expression also exhibits a
high level of variability even within families with the same aetiological
mutation, and may be influenced by additional genetic factors. Polymorphisms of
the renin-angiotensin-aldosterone system (RAAS) represent an attractive
hypothesis as potential disease modifiers, as these genetic variants alter the
'activation status' of the RAAS, which leads to more left ventricular
hypertrophy through different pathways. The main objective of this review is to
provide an overview of the role of different polymorphisms identified in the
RAAS, in patients with HCM. BACKGROUND: Hypertrophic cardiomyopathy (HCM) is a clinically heterogeneous
genetic heart disease characterized by left ventricular hypertrophy in the
absence of another disease that could explain the wall thickening. Elucidation
of the genetic basis of HCM lead to the identification of several genes encoding
sarcomeric proteins, such as MYH7, MYBPC3, TPM1, TNNT2, and TNNI3. Sarcomeric
genes are mutated in approximately 40% of HCM patients and a possible
explanation for the incomplete yield of mutation-positive HCM may be somatic
mutations.
METHODS AND RESULTS: We studied 104 unrelated patients with non-familial HCM.
Patients underwent clinical evaluation and mutation screening of 5 genes
implicated in HCM (MYH7, MYBPC3, TPM1, TNNT2, and TNNI3) in genomic DNA isolated
from resected cardiac tissue; 41 of 104 were found to carry a mutation, but as
several patients carried the same mutations, the total amount of different
mutations was 37; 20 of these mutations have been previously described, and
pathogenicity has been assessed. To determine the effect of the 17 new mutations
an in silico assay was performed and it predicted that 4 variants were damaging
mutations. All identified variants were also seen in the DNA isolated from the
corresponding blood, which demonstrated the absence of somatic mutations.
CONCLUSIONS: Somatic mutations in MYH7, MYBPC3, TPM1, TNNT2, and TNNI3 do not
represent an important etiologic pathway in HCM. PURPOSE: To present an overview of clinical issues related to adults with
hypertrophic cardiomyopathy (HCM), their presenting symptoms, diagnosis,
physical examination findings, treatment, and follow-up care.
DATA SOURCES: A comprehensive search of Medline (PubMed) and CINAHL was
conducted using the key terms HCM, treatment, diagnosis, sudden cardiac death
(SCD), and complications. This search yielded 21 articles used for this article.
There were three reference books used for background, diagnosis, and treatment
information as well.
CONCLUSIONS: Although HCM is the most prevalent genetic disorder affecting the
heart, it often goes undiagnosed until midlife after patients show symptoms of
myocardial remodeling. Adults with cardiomyopathy suffer SCD or adverse events
such as stroke and heart failure from HCM. Early diagnosis will prevent SCD,
improve quality of life, and slow patient's progression to heart failure.
IMPLICATIONS FOR PRACTICE: Early recognition of HCM in adults by their primary
care providers will improve patients' quality of life and reduce incidence of
SCD, heart failure, and stroke. Hypertrophic cardiomyopathy (HCM) is a genetic cardiomyopathy. The prevalence of
phenotypic expression, in the absence of another systemic or cardiac disease
causing increased left ventricular (LV) wall thickness, is estimated to be
1:500. The frequency of clinical presentation is far less, highlighting the need
for a non-invasive diagnostic imaging tool. Echocardiography is readily
available and allows for structural characterization and hemodynamic assessment
of the hypertrophic heart and to screen patients at-risk for HCM, such as first
degree relatives of affected individuals, and differentiate HCM from the
athletic heart. Echocardiography can also be used to assess for anatomic
abnormalities of the mitral valve apparatus that may exacerbate LV outflow track
obstruction and to further risk stratify patients during exercise. Finally,
echocardiography plays an integral role in guiding alcohol septal ablation
procedures. Hypertrophic cardiomyopathy (HCM) has been recently recognized as the most
common inherited cardiovascular disorder, affecting 1 in 500 adults worldwide.
HCM is characterized by myocyte hypertrophy resulting in thickening of the
ventricular wall, myocyte disarray, interstitial and/or replacement fibrosis,
decreased ventricular cavity volume and diastolic dysfunction. HCM is also the
most common cause of sudden death in the young. A large proportion of patients
diagnosed with HCM have mutations in sarcomeric proteins. However, it is unclear
how these mutations lead to the cardiac phenotype, which is variable even in
patients carrying the same causal mutation. Abnormalities in calcium cycling,
oxidative stress, mitochondrial dysfunction and energetic deficiency have been
described constituting the basis of therapies in experimental models of HCM and
HCM patients. This review focuses on evidence supporting the role of cellular
metabolism and mitochondria in HCM. AIMS: Familial hypertrophic cardiomyopathy (HCM) is one the most common heart
disorders, with gene mutations in the cardiac sarcomere. Studying HCM with
patient-specific induced pluripotent stem-cell (iPSC)-derived cardiomyocytes
(CMs) would benefit the understanding of HCM mechanism, as well as the
development of personalized therapeutic strategies.
METHODS AND RESULTS: To investigate the molecular mechanism underlying the
abnormal CM functions in HCM, we derived iPSCs from an HCM patient with a single
missense mutation (Arginine442Glycine) in the MYH7 gene. CMs were next enriched
from HCM and healthy iPSCs, followed with whole transcriptome sequencing and
pathway enrichment analysis. A widespread increase of genes responsible for
'Cell Proliferation' was observed in HCM iPSC-CMs when compared with control
iPSC-CMs. Additionally, HCM iPSC-CMs exhibited disorganized sarcomeres and
electrophysiological irregularities. Furthermore, disease phenotypes of HCM
iPSC-CMs were attenuated with pharmaceutical treatments.
CONCLUSION: Overall, this study explored the possible patient-specific and
mutation-specific disease mechanism of HCM, and demonstrates the potential of
using HCM iPSC-CMs for future development of therapeutic strategies.
Additionally, the whole methodology established in this study could be utilized
to study mechanisms of other human-inherited heart diseases. Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden cardiac
death (SCD) in the young, particularly among athletes. Identifying high risk
individuals is very important for SCD prevention. The purpose of this review is
to stress that noninvasive diagnostic testing is important for risk assessment.
Extreme left ventricular hypertrophy and documented ventricular tachycardia and
fibrillation increase the risk of SCD. Fragmented QRS and T wave inversion in
multiple leads are more common in high risk patients. Cardiac magnetic resoce
imaging provides complete visualization of the left ventricular chamber,
allowing precise localization of the distribution of hypertrophy and measurement
of wall thickness and cardiac mass. Moreover, with late gadolinium enhancement,
patchy myocardial fibrosis within the area of hypertrophy can be detected, which
is also helpful in risk stratification. Genetic testing is encouraged in all
cases, especially in those with a family history of HCM and SCD. Familial hypertrophic cardiomyopathy (HCM), due to point mutations in genes for
sarcomere proteins such as myosin, occurs in 1/500 people and is the most common
cause of sudden death in young individuals. Similar mutations in skeletal
muscle, e.g., in the MYH7 gene for slow myosin found in both the cardiac
ventricle and slow skeletal muscle, may also cause severe disease but the
severity and the morphological changes are often different. In HCM, the modified
protein function leads, over years to decades, to secondary remodeling with
substantial morphological changes, such as hypertrophy, myofibrillar disarray,
and extensive fibrosis associated with severe functional deterioration. Despite
intense studies, it is unclear how the moderate mutation-induced changes in
protein function cause the long-term effects. In hypertrophy of the heart due to
pressure overload (e.g., hypertension), mechanical stress in the myocyte is
believed to be major initiating stimulus for activation of relevant cell
signaling cascades. Here it is considered how expression of mutated proteins,
such as myosin or regulatory proteins, could have similar consequences through
one or both of the following mechanisms: (1) contractile instabilities within
each sarcomere (with more than one stable velocity for a given load), (2)
different tension generating capacities of cells in series. These mechanisms
would have the potential to cause increased tension and/or stretch of certain
cells during parts of the cardiac cycle. Modeling studies are used to illustrate
these ideas and experimental tests are proposed. The applicability of similar
ideas to skeletal muscle is also postulated, and differences between heart and
skeletal muscle are discussed. Hypertrophic cardiomyopathy (HCM) is a primary disease of the cardiac muscle
that occurs mainly due to mutations (>1,400 variants) in genes encoding for the
cardiac sarcomere. HCM, the most common familial form of cardiomyopathy,
affecting one in every 500 people in the general population, is typically
inherited in an autosomal domit pattern, and presents variable expressivity
and age-related penetrance. Due to the morphological and pathological
heterogeneity of the disease, the appearance and progression of symptoms is not
straightforward. Most HCM patients are asymptomatic, but up to 25% develop
significant symptoms, including chest pain and sudden cardiac death. Sudden
cardiac death is a dramatic event, since it occurs without warning and mainly in
younger people, including trained athletes. Molecular diagnosis of HCM is of the
outmost importance, since it may allow detection of subjects carrying mutations
on HCM-associated genes before development of clinical symptoms of HCM. However,
due to the genetic heterogeneity of HCM, molecular diagnosis is difficult.
Currently, there are mainly four techniques used for molecular diagnosis of HCM,
including Sanger sequencing, high resolution melting, mutation detection using
DNA arrays, and next-generation sequencing techniques. Application of these
methods has proven successful for identification of mutations on HCM-related
genes. This review summarizes the features of these technologies, highlighting
their strengths and weaknesses. Furthermore, current therapeutics for HCM
patients are correlated with clinically observed phenotypes and are based on the
alleviation of symptoms. This is mainly due to insufficient knowledge on the
mechanisms involved in the onset of HCM. Tissue engineering alongside
regenerative medicine coupled with otherapeutics may allow fulfillment of
those gaps, together with screening of novel therapeutic drugs and target
delivery systems. |
What is the genetic basis of Rubinstein-Taybi syndrome? | Rubinstein-Taybi syndrome (RTS) is a rare autosomal dominant disorder (prevalence 1:125,000) characterised by broad thumbs and halluces, facial dysmorphism, psychomotor development delay, skeletal defects, abnormalities in the posterior fossa and short stature. The known genetic causes are a microdeletion at 16p13.3 or mutations or deletions of the cAMP-response element binding protein-BP (CREBBP) (50-60% of the cases) and of the homologous gene E1A-binding protein (EP300) at 22q13 (5%). Direct sequencing of CREBBP performed in 13 RSTS patients identified the three zinc fingers (CH1, CH2, CH3) and HAT domain as mutational hotspots. Thus about 55% of patients have cytogenetic or molecular abnormalities in the Crebbp or E1A binding protein p300 (Ep300) gene, leaving the diagnosis in 45% of patients to rest on clinical features only. | The Rubinstein-Taybi syndrome (RTS) is a well-defined syndrome with facial
abnormalities, broad thumbs, broad big toes and mental retardation as the main
clinical features. Many patients with RTS have been shown to have breakpoints
in, and microdeletions of, chromosome 16p13.3 (refs 4-8). Here we report that
all these breakpoints are restricted to a region that contains the gene for the
human CREB binding protein (CBP), a nuclear protein participating as a
co-activator in cyclic-AMP-regulated gene expression. We show that RTS results
not only from gross chromosomal rearrangements of chromosome 16p, but also from
point mutations in the CBP gene itself. Because the patients are heterozygous
for the mutations, we propose that the loss of one functional copy of the CBP
gene underlies the developmental abnormalities in RTS and possibly the
propensity for maligcy. Rubinstein-Taybi syndrome (RTS) is a well-defined syndrome characterized by
facial abnormalities, broad thumbs, broad big toes, and growth and mental
retardation as the main clinical features. RTS was shown to be associated with
disruption of the CREB-binding protein gene CBP (CREBBP), either by gross
chromosomal rearrangements or by point mutations. Translocations and inversions
involving chromosome band 16p13.3 form the minority of CBP mutations, whereas
microdeletions occur more frequently (about 10%). Most deletion studies in RTS
are performed by FISH analysis, and five cosmids must be used to cover the whole
of the CBP gene, which spreads over 150 kb. Here we report the design of gene
dosage assays by real-time quantitative PCR that are targeted on three exons
located respectively at the 5' end (exon 2), in the middle (exon 12), and at the
3' end (exon 30) of the CBP gene. This technique proved to be efficient and
powerful in finding deletions and complementary to the other available
techniques, since it allowed us to identify deletions at the 3' end of the gene
that had been missed by FISH analysis, and to refine some deletion breakpoints.
Our results therefore suggest that real-time quantitative PCR is a useful
technique to be included in the deletion search in RTS patients. We report on a six-year-old boy with typical Rubinstein-Taybi syndrome (RSTS)
phenotype. Clinical findings included mental and motor retardation, patent
ductus arteriosus (PDA), undescended testes, hirsutism, broad thumbs with radial
angulation and broad toes, and inguinal hernia. His karyotype was normal (46,
XY) and fluorescence in situ hybridization (FISH) showed no deletion of the
CREBBP [cAMP response element-binding (CREB) binding protein] gene on chromosome
16p13.3. CREBBP gene sequencing also revealed normal results. We wish to present
this case because this patient had typical RSTS phenotype, but normal FISH and
CREBBP gene sequencing results. It could be possible that genetic heterogeneity
is related with novel mutations in other genes. With the publication of such
cases, their significance will be brought to the attention of researchers in
this field. Rubinstein-Taybi syndrome (RTS) is a rare autosomal domit genetic disorder
and is characterized by mental retardation, distinctive facial features, broad
and often angulated thumbs and great toes. We report on a 7 year old boy with
classical Rubinstein-Taybi syndrome. His facial and clinical features were very
typical, including broad thumbs with radial angulation and broad great toes.
Rigorous genetic analysis of the CREBBP and EP300 genes using DNA sequencing and
multiple ligation-dependent probe amplification (MLPA) revealed no causative
mutation in this boy, only a hitherto unreported but paternally inherited
heterozygous sequence alteration, c.506 1+9C>T in IVS 30-31, which most likely
represents a normal variant (NetGene 2 splice prediction software). We question
if this boy could have a hitherto undetectable mutation type. Rubinstein-Taybi syndrome or Broad Thumb-Hallux syndrome is a genetic disorder
characterized by facial dysmorphism, growth retardation, and mental deficiency.
A seven-year-old girl had come to the Department of Pedodontics, Istanbul
Medipol University, Faculty of Dentistry, Turkey, with a complaint of caries and
bleeding of gingivae. The patient was mentally retarded. Extraoral features
revealed distinctive facial appearance with a broad fore head, hypertelorism,
broad nasal bridge, and beaked nose. Intraoral features observed were talons
cusps in the upper lateral incisors, carious teeth, and plaque accumulation.
Since the patient was mentally retarded, the dental treatment was done under GA.
The treatment plan and dental management of this patient are discussed in this
case report. |
What is the function of the viral KP4 protein? | The virally encoded fungal toxin KP4 specifically blocks L-type voltage-gated calcium channels. | Killer toxins are polypeptides secreted by some fungal species that kill
sensitive cells of the same or related species. In the best-characterized cases,
they function by creating new pores in the cell membrane and disrupting ion
fluxes. Immunity or resistance to the toxins is conferred by the preprotoxins
(or products thereof) or by nuclear resistance genes. In several cases, the
toxins are encoded by one or more genomic segments of resident double-stranded
RNA viruses. The known toxins are composed of one to three polypeptides, usually
present as multimers. We have further characterized the KP4 killer toxin from
the maize smut fungus Ustilago maydis. This toxin is also encoded by a single
viral double-stranded RNA but differs from other known killer toxins in several
respects: it has no N-linked glycosylation either in the precursor or in the
mature polypeptide, it is the first killer toxin demonstrated to be a single
polypeptide, and it is not processed by any of the known secretory proteinases
(other than the signal peptidase). It is efficiently expressed in a heterologous
fungal system. Some strains of the plant-pathogenic fungus Ustilago maydis secrete toxins
(killer toxins) that are lethal to susceptible strains of the same fungus. There
are three well-characterized killer toxins in U. maydis-KP1, KP4, and KP6-which
are secreted by the P1, P4, and P6 subtypes, respectively. These killer toxins
are small polypeptides encoded by segments of an endogenous, persistent
double-stranded RNA (dsRNA) virus in each U. maydis subtype. In P4 and P6, the
M2 dsRNA segment encodes the toxin. In this work, the KP1 killer toxin was
purified for internal amino acid sequence analysis, and P1M2 was identified as
the KP1 toxin-encoding segment by sequence analysis of cDNA clones. The KP1
toxin is a monomer with a predicted molecular weight of 13.4kDa and does not
have extensive sequence similarity with other viral anti-fungal toxins. The P1M2
segment is different from the P4 and P6 toxin-encoding dsRNA segments in that
the 3' non-coding region of its plus strand has no sequence homology to the 3'
ends of the plus strands of P1M1, P4M2, or P6M2. The cDNA encoding the antifungal protein KP4 from Ustilago maydis-infecting
virus was inserted behind the ubiquitin promoter of maize and genetically
transferred to wheat varieties particularly susceptible to stinking smut
(Tilletia tritici) disease. The transgene was integrated and inherited over
several generations. Of seven transgenic lines, three showed antifungal activity
against U. maydis. The antifungal activity correlated with the presence of the
KP4 transgene. KP4-transgenic, soil-grown wheat plants exhibit increased
endogenous resistance against stinking smut. The viral gene for the killer protein 4 (KP4) has been explored for its
antifungal effect in genetically modified wheat to defeat specifically the
seed-transmitted smut and bunt diseases. In vitro both important
seed-transmitted diseases of wheat, loose smut (Ustilago tritici) and stinking
smut (Tilletia caries), are susceptible to KP4, whereas all other organisms
tested so far proved to be not susceptible to KP4. For studies in planta we used
stinking smut as a model fungus. In greenhouse experiments, two KP4-transgenic
wheat lines showed up to 30% lower symptom development as compared to the
nontransgenic control. As the last step in the proof of concept, field-testing
has shown for the first time increased fungal resistance of a transgene in
wheat. Due to its specificity against smuts and bunts, KP4 presents a very low
risk to humans and the environment. Field-testing in Switzerland is regulated by
a strong law, which for research is acceptable if legally and scientifically
correctly applied. Plant defensins are small, highly stable, cysteine-rich antimicrobial proteins
that are thought to constitute an important component of plant defense against
fungal pathogens. There are a number of such defensins expressed in various
plant tissues with differing antifungal activity and spectrum. Relatively little
is known about the modes of action and biological roles of these proteins. Our
previous work on a virally encoded fungal toxin, KP4, from Ustilago maydis and
subsequently with the plant defensin, MsDef1, from Medicago sativa demonstrated
that some of these proteins specifically blocked calcium channels in both fungi
and animals. The results presented here demonstrate that KP4 and three plant
defensins, MsDef1, MtDef2, and RsAFP2, all inhibit root growth in germinating
Arabidopsis seeds at low micromolar concentrations. We have previously
demonstrated that a fusion protein composed of Rab GTPase (RabA4b) and enhanced
yellow fluorescent protein (EYFP) is dependent upon calcium gradients for
localization to the tips of the growing root hairs in Arabidopsis thaliana.
Using this tip-localized fusion protein, we demonstrate that all four proteins
rapidly depolarize the growing root hair and block growth in a reversible
manner. This inhibitory activity on root and root hair is not directly
correlated with the antifungal activity of these proteins and suggests that
plants apparently express targets for these antifungal proteins. The data
presented here suggest that plant defensins may have roles in regulating plant
growth and development. Killer protein 4 (KP4) is a well studied viral toxin secreted by the maize smut
fungus Ustilago maydis that kills sensitive Ustilago strains as well as inhibits
Fusarium and plant root growth by inhibiting calcium uptake. Numerous small,
cysteine-rich proteins have been shown to play a critical role in
fungal-plant-bacterial associations. The discovery of six KP4-like genes in F.
verticillioides precipitated efforts to understand their function and
evolutionary origin. Analysis of publicly available genomic sequence identified
31 additional KP4-like genes from a range of Ascomycota, a Basidiomycota, and
the moss Physcomitrella patens. Sequence comparison and phylogenetic analysis
indicate that the viral KP4 and the moss and fungal KP4-like genes evolved from
a common ancestor providing evidence for lateral gene transfer between kingdoms.
Six genes of the 37 total genes are predicted to encode a protein with two,
non-identical KP4-like domains in tandem separated by 29-56 amino acids. The
results suggest that two independent events led to the dual-domain KP4 genes
present in different lineages of the Ascomycota. Understanding the nature and
function of KP4-like proteins in mycotoxin-producing species like Fusarium may
help to limit plant diseases and increase food safety and food production. The corn smut fungus, Ustilago maydis, is a global pathogen responsible for
extensive agricultural losses. Control of corn smut using traditional breeding
has met with limited success because natural resistance to U. maydis is organ
specific and involves numerous maize genes. Here, we present a transgenic
approach by constitutively expressing the Totivirus antifungal protein KP4, in
maize. Transgenic maize plants expressed high levels of KP4 with no apparent
negative impact on plant development and displayed robust resistance to
U. maydis challenges to both the stem and ear tissues in the greenhouse. More
broadly, these results demonstrate that a high level of organ independent fungal
resistance can be afforded by transgenic expression of this family of antifungal
proteins. |