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Query: UMLS:C0476089 (endometrial cancer)
 11,379 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activation of signal transducer and activator of transcription 3 (Stat3) has been implicated in the oncogenesis of cancer and is regarded as a novel target for cancer therapy. Stat3 is classified as a proto-oncogene, because an activated form of Stat3 can mediate oncogenic transformation in cultured cells and tumour formation in nude mice. The constitutive activation of Stat3 has been frequently detected in various types of human cancers. However, the constitutive activation of Stat3 in endometrial and cervical cancers has not been studied. We examined tyrosine phosphorylation of Stat3 (activated form of Stat3) in multiple endometrial and cervical cancer tissues using tissue microarray slides as well as cancer cell lines to explore the possible activation of Stat3. Our results indicated that elevated phosphorylation of Stat3 was detected in cervical and endometrial cancer cell lines. Our results also showed that elevated levels of phosphorylation of Stat3 protein were detected in the endometrial and cervical cancer specimens. This is the first study to demonstrate that Stat3 is activated in human endometrial and cervical cancer tissues. Immunohistochemical staining showed that activated Stat3 is associated with increased expression of downstream antiapoptotic genes, Bcl-xL, survivin, and Mcl-1 in these tissues. Expression of a dominant-negative Stat3 mutant using adenovirus-mediated gene transfer inhibited cell growth and induced apoptosis in HeLa and SiHa cervical cancer cell lines expressing elevated levels of Stat3 phosphorylation. Further, a JAK/Stat3 small molecular inhibitor, JSI-124, induced apoptosis more selectively in HeLa and SiHa cancer cell lines than Ishikawa cell line without elevated levels of Stat3 phosphorylation. These results indicate that Stat3 is activated in human endometrial and cervical cancers and the inhibition of constitutive Stat3 signaling may be an effective target for cancer intervention in these two cancers.
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PMID:Stat3 activation in human endometrial and cervical cancers. 1731 Oct 11

In this study, we explore the therapeutic potential of lapatinib a selective inhibitor of both the EGFR and HER2 tyrosine kinases for the treatment of endometrial cancer. The effect of lapatinib on tumour cell growth and receptor activation was studied in a panel of human endometrial cancer cell lines. Candidate molecular markers predicting sensitivity were assessed by baseline gene expression profiling, ELISA, and western blot analyses. Multiple drug effect/combination index (CI) isobologram analysis was used to study the interactions between chemotherapeutic drugs and lapatinib. Concentration-dependent anti-proliferative effects of lapatinib were seen in all endometrial cancer cell lines tested, but varied significantly between individual cell lines (IC(50) range: 0.052-10.9 micromol). HER2 overexpression or increased expression of EGFR was significantly associated with in vitro sensitivity (P=0.024 or 0.011, respectively). Lapatinib exerts growth inhibition in a PTEN-independent manner. Sensitive cell lines also exhibited increased expression of EGFR ligands or HER3. In contrast, lapatinib-resistant cell lines exhibited high androgen receptor (AR) levels or epithelial-to-mesenchymal transition (post-EMT) features. In endometrial cancer cells, at a wide range of clinically achievable drug concentrations, additive and synergistic interactions were observed for lapatinib plus carboplatin, paclitaxel, docetaxel, and doxorubicin. These observations provide a clear biologic rational to test lapatinib as a single agent or in combination with chemotherapy in endometrial cancer with HER2 overexpression. Expression of EGFR, its ligands, HER3, AR, and post-EMT markers warrant further evaluation to help define patients with HER2-nonoverexpressing endometrial cancer most likely to benefit from lapatinib.
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PMID:Activity of lapatinib a novel HER2 and EGFR dual kinase inhibitor in human endometrial cancer cells. 1833 72

Oncogenic activation of tyrosine kinases is a common mechanism of carcinogenesis and, given the druggable nature of these enzymes, an attractive target for anticancer therapy. Here, we show that somatic mutations of the fibroblast growth factor receptor 2 (FGFR2) tyrosine kinase gene, FGFR2, are present in 12% of endometrial carcinomas, with additional instances found in lung squamous cell carcinoma and cervical carcinoma. These FGFR2 mutations, many of which are identical to mutations associated with congenital craniofacial developmental disorders, are constitutively activated and oncogenic when ectopically expressed in NIH 3T3 cells. Inhibition of FGFR2 kinase activity in endometrial carcinoma cell lines bearing such FGFR2 mutations inhibits transformation and survival, implicating FGFR2 as a novel therapeutic target in endometrial carcinoma.
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PMID:Drug-sensitive FGFR2 mutations in endometrial carcinoma. 1855 76

Sprouty 2 is a key antagonist regulator of receptor tyrosine kinases, and downstream signaling pathways, like fibroblastic growth factor (FGF) and Ras-mitogen-activated protein kinase (RAS-MAPK). By controlling these pathways, sprouty 2 is involved in regulation of cell proliferation, differentiation, and angiogenesis. Alterations in fibroblastic growth factor receptor (FGFR) and members of the RAS-MAPK pathway are frequent in endometrial carcinoma. The expression of sprouty 2 has been found to be decreased in several types of human cancer, by mechanisms of promoter methylation. In the present study, we have assessed the expression of sprouty 2 in endometrial carcinoma, in correlation with sprouty 2 promoter methylation. Sprouty 2 immunohistochemical expression was assessed using 3 different tissue microarrays: one constructed from paraffin blocks of 80 samples of normal endometrium and 2 tissue microarrays containing samples of 157 endometrial carcinoma (1 tissue microarray constructed with 95 endometrial carcinomas previously studied for microsatellite instability and alterations in phosphatase and tensin homolog (PTEN), k-ras, and b-catenin, and 1 tissue microarray containing 62 endometrial carcinoma, which were also subjected to sprouty 2 promoter methylation analysis). The immunohistochemical expression of sprouty 2 was correlated with cellular proliferation (Ki67) and clinicopathologic data. Sprouty 2 promoter methylation was assessed by methylation-specific polymerase chain reaction, with DNA obtained from fresh-frozen samples of endometrial carcinoma and corresponding normal tissues, and correlated with promoter methylation of RAS association domain family-1A (RASSF1A). A highly significant decrease in sprouty 2 immunoexpression was seen in the proliferative phase of normal endometrium (P < .001). Differences were detected between types I and II endometrial carcinoma, but they were not statistically significant. Reduced immunoexpression of sprouty 2 was seen in 19.85% of endometrial carcinoma and was strongly and inversely associated with increased cell proliferation (Ki67; r = -0.367; P = .001). Sprouty 2 promoter methylation was detected in 31 (53.4%) of 58 endometrial carcinomas. Results from our study show that alterations in sprouty 2 may be involved in endometrial carcinogenesis by controlling cell proliferation.
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PMID:Promoter hypermethylation and expression of sprouty 2 in endometrial carcinoma. 2111 54

This study was designed to elucidate the signal transduction mechanisms, mediating the antiproliferative effects of analogs of luteinizing hormone releasing hormone (LHRH) on cell lines derived from human cancers of the ovary (EFO-21, EFO-27) and the endometrium (HEC-1A, Ishikawa). The LHRH agonist triptorelin had no measurable effects on the activity of phospholipase C, protein kinase C, or adenylate cyclase in all 4 cell lines, though these enzymes could be activated through pharmacological stimuli. The proliferation of EFO-21, EFO-27 and HEC-1A cells in serum/phenol red-free medium was significantly stimulated by epidermal growth factor (EGF). This mitogenic effect of EGF was dose dependently antagonized by triptorelin, without affecting the concentrations of EGF receptors. Net tyrosine phosphorylation induced by 1 nM EGF was nearly completely suppressed by simultaneous addition of 10 mu M triptorelin or preincubation for 48 h with 100 nM triptorelin. This inhibitory effect of the LHRH agonist on EGF-induced net tyrosine phosphorylation was partly antagonized by exposure to 100 mu M sodium vandate, an inhibitor of phosphotyrosine phosphatase. In EFO-21, EFO-27, and HEC-1A cells exposure to 100 nM EGF for 5 min induced an approximately 5-fold increase in activity of mitogen activated protein kinase (MAP-kinase)/extracellular signal regulated kinase (ERK) which was virtually nullified, when the cells were exposed for 15 min to 10 mu M triptorelin. These data suggest that LHRH signal transduction mechanisms based on the activation of phospholipase C, protein kinase C, and adenylate cyclase, which operate in the pituitary gonadotroph, are not necessarily involved in the mediation of the antiproliferative effects of triptorelin in these ovarian and endometrial cancer cell lines. Instead our findings support the hypothesis that triptorelin interferes with mitogenic signal transduction, probably through antagonizing tyrosine kinase activity of the EGF receptor.
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PMID:Luteinizing hormone-releasing hormone agonist triptorelin antagonizes signal transduction and mitogenic activity of epidermal growth factor in human ovarian and endometrial cancer cell lines. 2154 21

Prolactin (PRL) blocks the mitogenic activity of the endometrium via a PRL receptor (PRL-R)-mediated mechanism (Proc Soc Exp Biol Med 203: 117, 1993, ibid 205: 140, 1994). To elucidate the molecular mechanism of the antimitogenic action of PRL, we examined the PRL receptor-linked tyrosine kinase and phosphotyrosine phosphatase (PTP), known to constitute the signaling of cell growth, within isolated plasma membranes from endometrium and endometrial carcinoma. Surgically removed human endometrial carcinomas and normal endometrium were examined. PRL receptor mRNA was determined by reverse transcription-polymerase chain reaction using oligonucleotide primers synthesized according to the published human PRL receptor sequence. Phosphotyrosine-containing membrane proteins were analyzed using antiphosphotyrosine antibody in Western blots. Plasma membrane-associated PTP activity was examined using the synthetic substrate para-nitrophenyl phosphates (p Npp) in a spectrophotometric assay, PRL receptor mRNA was detected in all endometria tested, 7 of 9 samples of well-differentiated adenocarcinoma, 7 of 8 of poorly-differentiated adenocarcinoma. In plasma membrane isolated from PRL receptor mRNA-positive specimens, PRL induced dose-dependent (i) decrease in the level of tyrosine-phosphorylated protein and (ii) inhibition of PTP activity in the presence of nonhydrolyzable GTP. PRL alone showed no hormonal action. PRL may decrease the phosphotyrosine level in protein substrates through block of tyrosine kinase. The PRL receptor-linked tyrosine phosphorylation may be mediated by a GTP-binding protein. The inhibition of the tyrosine kinase suggests an involvement of this enzyme in the growth-inhibiting action of PRL.
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PMID:Prolactin receptor-linked tyrosine-phosphorylation of membrane-proteins is mediated by GTP-binding protein in endometrial carcinoma and endometrium. 2155 25

The phosphotyrosine phosphatase (PTPase) decreases the level of phosphotyrosine of intracellular protein substrates, thereby reversing the action of tyrosine phosphorylation to promote cell growth and differentiation. We determined the activities of PTPases in normal and cancerous tissues of the endometrium. The PTPase activity was determined with the synthetic substrate p-nitrophenyl in a spectrophotometric assay. Over 90% of the activity was particulate and the values in proliferative- and secretory-phase endometria and endometrial carcinomas fell within a similar range. This work demonstrates the existence of PTPase activity, counterbalancing the growth-promoting effects of tyrosine kinases, in endometrial carcinoma.
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PMID:Phosphotyrosine phosphatase-activity in membranes from endometrial carcinoma. 2159 52

Among female-specific cancers worldwide, endometrial cancer is the third most common after breast cancer and cervical cancer. In addition, it is the most common gynecological cancer in the USA and Europe. The incidence of this disease appears to be increasing. The cause of this increase is multifactorial, but a few possible factors involved are increasing obesity, an aging population leading to more postmenopausal women and greater tamoxifen use. Surgery is generally the primary treatment of this disease and postoperative radiation therapy in some patients with high or intermediate risk may prevent locoregional recurrences. Adjuvant chemotherapy improves progression-free survival in advanced or recurrent cancer. However, overall survival in patients with advanced disease is poor. Hence, better therapy is needed and targeted molecular therapies are emerging as possible treatment candidates. These include molecules that target VEGF, mTOR, tyrosine kinases, human EGF receptors and FGF receptors. Therapies targeting specific molecular features should be evaluated in future strategies in the treatment of endometrial cancer.
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PMID:Targeted endometrial cancer therapy as a future prospect. 2347 24

The decapeptide GnRH is known for its central role in the regulation of the hypothalamo-pituitary-gonadal axis. In addition, it is also known to have local effects within peripheral tissues. The zinc metalloendopeptidase, EC 3.4.24.15 (EP24.15), can cleave GnRH at the Tyr(5)-Gly(6) bond to form the pentapeptide, GnRH-(1-5). The central and peripheral effect of GnRH-(1-5) is different from its parent peptide, GnRH. In the current study, we examined the effect of GnRH-(1-5) on epidermal growth factor receptor (EGFR) phosphorylation and cellular migration. Using the Ishikawa cell line as a model of endometrial cancer, we demonstrate that GnRH-(1-5) stimulates epidermal growth factor release, increases the phosphorylation of EGFR (P < .05) at three tyrosine sites (992, 1045, 1068), and promotes cellular migration. In addition, we also demonstrate that these actions of GnRH-(1-5) are mediated by the orphan G protein-coupled receptor 101 (GPR101). Down-regulation of GPR101 expression blocked the GnRH-(1-5)-mediated release of epidermal growth factor and the subsequent phosphorylation of EGFR and cellular migration. These results suggest that GPR101 is a critical requirement for GnRH-(1-5) transactivation of EGFR in Ishikawa cells.
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PMID:GnRH-(1-5) transactivates EGFR in Ishikawa human endometrial cells via an orphan G protein-coupled receptor. 2426 76

Intratumor heterogeneity implies heterogeneous protein function, facilitating tumor adaptation which results in therapeutic failure. We hypothesized that tumor heterogeneity at protein level may influence the course of the disease. As a single biopsy might not represent the full biologic complexity of the tumor, we have analyzed immunohistochemically four different cores obtained from each primary tumor within the cohort of 364 patients with endometrial cancer (EC). The following proteins were examined: estrogen receptor 1 (ESR1), progesterone receptor, epidermal growth factor receptor, v-erb-b2 erythroblastic leukemia viral oncogene homolog 2, receptor tyrosine-protein kinase erbB-3, v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 4, phosphatidylinositol-4,5-bisphosphate 3-kinase, phosphorylated v-akt murine thymoma viral oncogene homolog 1, v-myc avian myelocytomatosis viral oncogene homolog, DNA topoisomerase II alpha 170 kDa (TOP2A), cyclin-dependent kinase inhibitor 2A (CDKN2A), tumor protein p53, RAD21 homolog, S. pombe, and runt-related transcription factor 1. Particularly strong correlation was found between TOP2A and CDKN2A heterogeneity and higher stage of the disease (P = .0002 and P = .0003, respectively). Most correlations with clinicopathologic data were observed for ESR1 heterogeneity that correlated with non-endometrioid carcinomas (P=.02), higher stage (P=.005), grade (P=.01), and the presence of metastases (P = .01). Thirty-nine (11.0%) patients were classified as "globally heterogeneous". Cumulative tumor heterogeneity strongly correlated with the presence of metastases, higher stage, and higher grade of the disease (all P b .05). It also carried negative prognostic value (P=.0008). We show that the degree of heterogeneity in EC might serve as a clinically valid molecular marker.
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PMID:Tumor heterogeneity at protein level as an independent prognostic factor in endometrial cancer. 2504 28


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