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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. |
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