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

The presence of a direct extra-pituitary action of gonadotropin-releasing hormone (GnRH) via specific receptors in endometrial cancer (EC) has been suggested as an explanation for the therapeutic effect of GnRH analogue (GnRHa) in recurrent disease. We have sought the expression of the GnRH peptide and functional GnRH receptor (GnRH-R) in human tissues and cell lines to investigate the possibility of an autocrine growth regulation mechanism. Using reverse transcription-PCR, differing GnRH mRNA transcripts were detected in two EC cell lines (Ishikawa and HEC-1A), a choriocarcinoma (JEG3) cell line, and tissues from endometrium and placenta. However, secretion of immunoreactive GnRH could be detected by RIA in only 1 of 10 EC tissues in primary culture, and in none of the cell lines. Low levels of GnRH-R mRNA expression were found in the same cells, which were only detectable by reverse transcription-PCR and Southern blotting of the PCR product. In radioligand binding assays using GnRHa goserelin, no pituitary-like, high-affinity GnRH binding sites could be found in either EC cell lines or tissues. Low affinity binding (Kd = 1.0 - 3.1 x 10(-7)M) was detected in three of eight (37%) EC tissues. Furthermore, receptor signal transduction measurements carried out in these cells showed no increases in either total inositol phosphate, cyclic AMP production, or cytosolic Ca2+ in response to either GnRH or GnRHa. Finally, no effect of either GnRH or GnRHa on the growth of EC cell lines was detected in vitro, under estrogen-free conditions, assessed by DNA content. Our data suggest that although there is a potential for autocrine activity for GnRH in EC as judged by the presence of mRNA for peptide and receptor, no functional receptor activity could be detected in vitro. Alternative mechanisms should be studied to explain the in vitro action of GnRHa.
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PMID:The expression of gonadotropin-releasing hormone and its receptor in endometrial cancer, and its relevance as an autocrine growth factor. 861 51

Fas ligand induces cell death by means of apoptosis in a variety of cell types when cross-linked with its natural receptor, Fas. GnRH receptor-bearing tumors undergo apoptosis in vivo and in vitro with GnRH agonists. To provide a potential association of the Fas system with the antiproliferative signaling process of GnRH receptor, we have evaluated the regulation of Fas ligand expression in GnRH receptor-positive tumors and cloned cell lines known to have substantial GnRH receptors. Surgically removed uterine endometrial carcinomas and ovarian carcinomas had been screened for GnRH receptor expression before analysis. Fas ligand protein was characterized by immunoblotting of membrane proteins with the specific antibody. Fas ligand messenger RNA was determined by RT-PCR using oligonucleotide primers synthesized according to the published Fas ligand sequence. Incubation with a GnRH analog (1 mumol/L) induced the expression of Fas ligand messenger RNA and immuno-reactive Fas ligand with a lag time of 48 h in cloned cell lines (endometrial carcinoma HHUA cells, and ovarian carcinoma SK-OV-3 and Caov-3 cells). There was no detectable Fas ligand expression within 24 h. The stimulatory effect of GnRH on Fas ligand protein expression revealed a dose dependency; a half-maximal effect occurred with 10 nmol/L GnRH analog (P < 0.01). The stimulated Fas ligand expression could be neutralized by displacement of GnRH from its receptor by GnRH antagonist antide. Cells isolated from GnRH receptor-bearing ovarian carcinomas and uterine endometrial carcinomas gave identical results to those obtained in cloned cell lines. These data demonstrate the functional coupling of stimulated Fas ligand expression to GnRH receptor activation. Increased Fas ligand level within the GnRH receptor-bearing tumors might promote apoptotic cell death through attack on intratumoral Fas-positive cells that could, at least in part, account for the antiproliferative action of the hormone.
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PMID:Evidence for tight coupling of gonadotropin-releasing hormone receptor to stimulated Fas ligand expression in reproductive tract tumors: possible mechanism for hormonal control of apoptotic cell death. 946 52

Gonadotropin-releasing hormone (GnRH) receptor-bearing tumors undergo apoptosis in vivo and in vitro with GnRH analogs. We recently showed that GnRH stimulation induces intratumoral expression of the apoptosis-inducing Fas ligand in human reproductive tract tumors. To provide a potential association of Fas/Fas ligand system with the antiproliferative signaling process of GnRH receptor, we evaluated a correlation between the Fas ligand expression and the number of viable cells in two types of GnRH receptor-bearing endometrial carcinomas that differ in Fas content. Surgically removed uterine endometrial carcinomas had been screened for the presence of GnRH receptor and Fas before analyses. Fas ligand protein was characterized by immunoblotting of membrane proteins with the specific antibody. After a lag time of 2 days, incubation with a GnRH analog leuprolide (10 microM) induced significant growth inhibition of the Fas- and GnRH receptor-bearing cells (p<0.01). Time course analysis showed that Fas ligand production, which was already observed at day 2 (p<0.01), precedes the onset of reduction in viable cell number. The stimulatory effect of GnRH on Fas ligand expression and reduction of viable cells revealed dose-dependency. The analog at concentration of 10 microM induced up to 90% reduction in cell number. In contrast, the growth of Fas-negative cells was not affected by the analog, although Fas ligand appeared in response to the GnRH analog (p<0.01). These data demonstrate that the co-presence of Fas could be essential for GnRH to promote antiproliferative action in endometrial cancer cells carrying GnRH receptor. The hormone may act through intratumor Fas and Fas ligand system to induced growth inhibition in GnRH-sensitive tumors.
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PMID:Fas and Fas ligand system may mediate antiproliferative activity of gonadotropin-releasing hormone receptor in endometrial cancer cells. 962 9

Gonadotropin-releasing hormone (GnRH) has been shown to have an inhibitory effect on the growth of several hormone-dependent human tumors. We have treated a human endometrial cancer cell line which expresses GnRH receptor with GnRH analog, D-Trp6-LHRH, in order to study whether there are differences in cell cycle kinetic response. Flow cytometric analysis revealed that cultured carcinoma cells showed a cell cycle arrest at the G1-S transition after treatment with 10 microM D-Trp6-LHRH for 36 h. Western blot analysis showed that the level of p16 protein was obvious following 24 h of D-Trp6-LHRH treatment. These results suggest that the mechanism by which GnRH inhibits the growth of endometrial carcinoma cells may include effects on cell cycle arrest.
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PMID:Cell cycle arrest in endometrial carcinoma cells exposed to gonadotropin-releasing hormone analog. 1036 62

Six endometrial cancer cell lines (Ishikawa, EIIL, HEC1A, 6, 50 and 59), one breast cancer cell line (MCF-7) and two ovarian cancer cell lines (OVHS-1, HRA) were treated for 24 or 168 h with a gonadotropin-releasing hormone (GnRH) analogue, Buserelin acetate, and the cellular growth profile was studied. All these cell lines except for the HRA line had positive GnRH receptor mRNA expression detected by reverse transcriptase polymerase chain reaction. GnRHa suppressed cell growth after 168 h of exposure, but not after 24 h. Suppression of cell growth by the exposure to cis-platinum (CDDP, 10 nM for 24 h) was significantly increased in the presence of GnRHa for 168 h. The mechanism of this growth inhibition was tested by examining both RNA components of human telomerase (hTR) expression and telomerase activity. The results showed that GnRHa inhibits telomerase activity without altering the RNA component of telomerase expression. The present data suggest that GnRH analogue may modulate endometrial, breast and ovarian cancer cell growth through modifying the telomerase activity. Since GnRHa increased the cytotoxic effects of CDDP and GnRHa is a compound of high patient compliance, the value of GnRHa as a tumor sensitizer to CDDP should be further tested in clinical trials.
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PMID:In vitro effects of gonadotropin-releasing hormone (GnRH) analogue on cancer cell sensitivity to cis-platinum. 1038 Nov 37

Gonadotropin-releasing hormone (GnRH) receptor is demonstrated in uterine endometrial carcinoma. The endometrial carcinoma also produces GnRH or -like peptide, which prompted us to examine whether the intratumoral serves as natural ligand for its receptor. Endometrial carcinomas surgically removed had been screened for GnRH receptor expression before analysis. The in endometrial carcinoma cell-enriched culture media was characterized by immunoblots in tricine-supplied electrophoresis system and subsequent amino acid sequencing. Three major proteins of 10.0 kDa, 7.6 kDa and 1.1 kDa corresponding to pre-proGnRH, proGnRH and decapeptide GnRH, respectively, were detected in all of the ten endometrial carcinoma specimens tested. Immunoreactive contents in the culture media, assessed by RIA, ranged from 0.08 to 0.1 nM. In chorionic cell-conditioned media, only 1.1-kDa protein was detected. Endometrial carcinoma cells secrete alternative GnRH processing products in addition to natural GnRH. The GnRH variants may compete with mature GnRH at the level of its receptors, perhaps counteracting the GnRH signaling pathway to retard cell proliferation.
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PMID:Alternative gonadotropin-releasing hormone processing products secreted from endometrial carcinoma. 1060 5

The expression of GnRH and its receptor as a part of an autocrine regulatory system of cell proliferation has been demonstrated in a number of human malignant tumors, including cancers of the breast, ovary and endometrium. Dose-dependent antiproliferative effects of GnRH agonists in cell lines derived from these cancers have been observed by various investigators. GnRH antagonists also have marked antiproliferative activity in most breast, ovarian and endometrial cancer cell lines tested, indicating that the dichotomy of GnRH agonists and antagonists might not apply to the GnRH system in cancer cells. The classical GnRH receptor signal-transduction mechanisms, known to operate in the pituitary, are not involved in the mediation of antiproliferative effects of GnRH analogs in cancer cells. Rather, the GnRH receptor interacts with the mitogenic signal transduction of growth factor receptors and related oncogene products associated with tyrosine kinase activity, via activation of a phosphotyrosine phosphatase, resulting in downregulation of cancer cell proliferation. In addition, GnRH activates nuclear factor kappaB and protects the cancer cells from apoptosis. Furthermore, GnRH induces activation of the c-Jun N-terminal kinase/activator protein-1 (AP-1) pathway independent of the known AP-1 activators, protein kinase or mitogen activated protein kinase.
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PMID:Biology of the gonadotropin-releasing hormone system in gynecological cancers. 1175 Oct 60

We investigated the relationship between the antiproliferative effect of GnRH agonist and telomerase activity using the endometrial cancer cell line HEC-1A. The subjects were 38 endometrial cancer, and 2 atypical endometrial hyperplasia patients. GnRH-R expression was detected using RT-PCR. HEC-1A cells were incubated with 10(-7)-10(-4) M GnRH agonist (leuprolide acetate), and cell proliferation was determined using MTT assay. The telomerase activity was detected by the TRAP assay and expression of human telomerase reverse transcriptase (hTERT) was assessed by RT-PCR. GnRH-R mRNA was detected at 94.7% (36/38) in endometrial cancer and in both of the atypical endometrial hyperplasia and in HEC-1A cells. Cell proliferation of HEC-1A showed significant inhibition at leuprolide acetate concentrations of 10(-6) M or higher compared with untreated control culture (p<0.05). The telomerase activity showed no marked difference compared with untreated culture. However, hTERT mRNA expression showed a decrease in the leuprolide-treated cells. It is suggested that the mechanism of the antitumor effect of GnRH agonist involved the inhibition of hTERT mRNA expression in the endometrial cancer cells.
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PMID:GnRH agonist inhibits human telomerase reverse transcriptase mRNA expression in endometrial cancer cells. 1237 98

The majority of ovarian, endometrial, and breast cancers express gonadotropin-releasing hormone (GnRH) receptors. Apart from reproductive organs (ovaries, fallopian tubes, and uterus) that are normally removed during surgical therapy of ovarian or endometrial cancer, pituitary gonadotrophs also express GnRH receptors. The signal transduction pathway in tumor cells is basically different from the classic GnRH receptor signal transduction, which is known to operate in the pituitary gonadotrophs and can therefore be considered tumor specific. Other organs and hematopoetic stem cells do not express GnRH receptors. We have recently shown specific activation of nucleus factor kappaB in ovarian, endometrial, and breast cancers after treatment with GnRH agonists. Based on this tumor-specific signaling pathway and the distribution pattern of GnRH receptors, we have developed and successfully tested a gene therapy concept by using a GnRH analogue as an inducer for the transcription of a therapeutic gene in cell culture and in nude mice.
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PMID:Gonadotropin-releasing hormone receptor-targeted gene therapy of gynecologic cancers. 1571 94

Several studies have previously reported the expression of the gonadotropin-releasing hormone receptor (GnRHr) in cases of endometrial cancer. However, the relationship between GnRHr expression and a variety of clinicopathologic parameters remains unclear. This study was conducted with 141 endometrial cancer patients, all of whom had undergone operations between 1993 and 2002. Paraffin-embedded tissue blocks were sectioned and immunostained with monoclonal anti-GnRHr antibody. Clinicopathologic variables were also evaluated, with 10% cutoff values for GnRHr positivity. Seventy specimens (49.6%) stained as GnRHr-positive. Mean parity was higher in the patients with GnRHr-positive tumors than those with GnRHr-negative tumors (2.50+/-1.92 versus 1.82+/-1.37, P=0.016). Body mass indices were also higher in the patients with GnRHr-positive tumors (26.6+/-4.6 versus 24.7+/-4.2, P=0.010). However, GnRHr positivity was not determined to be statistically significantly associated with any other clinicopathologic characteristics, including age, menopausal status, histotype, disease stage, tumor differentiation, lymph node metastasis, and myometrial invasion. The results of this study, although they may require further investigation, suggested that obese and multiparous women with endometrial cancer might be greatly influenced by endogenous gonadotropin-releasing hormone and/or exogenous gonadotropin-releasing hormone analogs.
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PMID:Gonadotropin-releasing hormone receptor expression in endometrial cancer. 1904 13


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