GnRH-II mRNA expression in tumor tissue and peripheral blood mononuclear cells (PBMCs) in patients with malignant and benign ovarian tumors.
ABSTRACT To investigate the expression of the second form of GnRH (GnRH-II) in tumor tissue and peripheral blood mononuclear cells (PBMCs) in malignant and benign ovarian tumors in humans.
Sixty-six women were studied: 24 with epithelial ovarian carcinomas, 22 with benign ovarian tumors and 20 in the control group undergoing surgery. Malignant, benign and normal ovarian tissue and PBMCs were obtained for measurement of GnRH-II mRNA levels using quantitative real-time RT-PCR.
The expression of GnRH-II was found to be 1.5 times higher in malignant ovarian tumors compared with benign ovarian tumors and the control group in post-menopausal patients (P<0.01). In the post-menopausal patient group with malignant ovarian tumors, there were significant positive correlations between serum FSH level and ovarian tissue GnRH-II mRNA expression (r=0.68; P=0.03), and serum LH level and ovarian tissue GnRH-II mRNA expression (r=0.71; P=0.02). Controls, benign and malignant groups were similar in terms of GnRH-II expression in PBMCs in the pre- and post-menopausal periods. There was no significant correlation between ovarian tissue GnRH-II mRNA expression vs. PBMC GnRH-II mRNA expression in patient and control groups.
We have shown increased GnRH-II expression in human ovarian cancer tissue in post-menopausal women in vivo. Expression of GnRH-II in PBMCs did not reflect the local GnRH-II expression levels in ovarian tissue. These preliminary data suggest that local GnRH-II may participate in the regulation of ovarian tumor growth in post-menopausal women.
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ABSTRACT: Epithelial ovarian cancer, which accounts for 80-90% of all ovarian cancers, is the most common cause of death from gynecological malignancies and is believed to originate from the ovarian surface epithelium. In the present study we investigated the expression of GnRH and its receptor in human ovarian surface epithelial (hOSE) cells and provided novel evidence that GnRH may have antiproliferative effects in this tissue. Using RT-PCR and Southern blot analysis, we cloned the GnRH and GnRH receptor (GnRHR) in hOSE cells. Sequence analysis revealed that GnRH and its receptor have sequences identical to those found in the hypothalamus and pituitary, respectively. To address whether GnRH regulates its own and receptor messenger RNA (mRNA), the cells were treated with different concentrations of the GnRH agonist (D-Ala6)-GnRH. Expression levels of GnRH and its receptor were investigated using quantitative and competitive RT-PCR, respectively. Interestingly, a biphasic effect was observed for the GnRH and GnRHR mRNA levels. High concentrations of the GnRH agonist (10(-7) and 10(-9) M) decreased GnRH and GnRHR mRNA levels, whereas a low concentration (10(-11) M) resulted in up-regulation of GnRH and receptor mRNA levels. Treatment with the GnRH antagonist, antide, prevented the biphasic effects of the GnRH agonist in hOSE cells, confirming the specificity of the response. Furthermore, to investigate the physiological significance, we studied receptor-mediated growth regulatory effects of GnRH in human ovarian surface epithelial cells. The cells were treated with GnRH analogs, and the proliferative index of cells was measured using a [3H]thymidine incorporation assay. (D-Ala6)-GnRH had a direct inhibitory effect on the growth of hOSE cells in a time- and dose-dependent manner. This antiproliferative effect of the GnRH agonist was receptor mediated, as cotreatment of hOSE cells with antide abolished the growth inhibitory effects of the GnRH agonist. The results strongly suggest that GnRH can act as an autocrine/paracrine regulator in hOSE cells.Endocrinology 01/2000; 141(1):72-80. · 4.72 Impact Factor
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ABSTRACT: Although gonadotropin-releasing hormone (GnRH) has been shown to play a role as an autocrine/ paracrine regulator of cell growth in ovarian surface epithelium and ovarian cancer, the factors which regulate the expression of GnRH and its receptor in these cells are not well characterized. In the present study, we employed real-time PCR to determine the potential regulatory effect of gonadotropins on the expression levels of GnRH I (the mammalian GnRH), GnRH II (a second form of GnRH) and their common receptor (GnRHR) in immortalized ovarian surface epithelial (IOSE-80 and IOSE-80PC) cells and ovarian cancer cell lines (A2780, BG-1, CaOV-3, OVCAR-3 and SKOV-3). The cells were treated with increasing concentrations (100 and 1000 ng/ml) of recombinant follicle-stimulating hormone (FSH) or luteinizing hormone (LH) for 24 h. Treatment with FSH or LH reduced GnRH II mRNA levels in both IOSE cell lines and in three out of five ovarian cancer cell lines (A2780, BG-1 and OVCAR-3). A significant decrease in GnRHR mRNA levels was observed in IOSE and ovarian cancer cells, except CaOV-3 cells, following treatment with FSH or LH. In contrast, treatment with either FSH or LH had no effect on GnRH I mRNA levels in these cells, suggesting that gonadotropins regulate the two forms of GnRH and its receptor differentially. In separate experiments, the effect of gonadotropins on the anti-proliferative action of GnRH I and GnRH II agonists in IOSE-80, OVCAR-3 and SKOV-3 cells was investigated. The cells were pretreated with FSH or LH (100 ng/ml) for 24 h after which they were treated with either GnRH I or GnRH II (100 ng/ml) for 2 days, and cell growth was assessed by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide] assay. Pretreatment of the cells with FSH or LH significantly reversed the growth inhibitory effect of GnRH I and GnRH II agonists in these cell types. These results provide the first demonstration of a potential interaction between gonadotropins and the GnRH system in the growth regulation of normal ovarian surface epithelium and its neoplastic counterparts.Endocrine Related Cancer 07/2006; 13(2):641-51. · 5.26 Impact Factor
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ABSTRACT: The purpose of this study was to investigate the expression of gonadotropin-releasing hormone messenger ribonucleic acid and the presence of gonadotropin-releasing hormone in human ovarian carcinoma known to have gonadotropin-releasing hormone binding sites and to be affected by gonadotropin-releasing hormone analog. Human ovarian carcinomas surgically removed and human ovarian carcinoma cell lines were examined. Gonadotropin-releasing hormone was determined by a radioimmunoassay and a bioassay. Gonadotropin-releasing hormone messenger ribonucleic acid was determined by reverse transcription polymerase chain reaction using oligonucleotide primers synthesized according to the published human gonadotropin-releasing hormone sequence. Gonadotropin-releasing hormone was shown to be present in extracts of ovarian mucinous cystadenocarcinoma sample (0.8 +/- 0.12 pg/mg of protein) and ovarian adenocarcinoma cell line SK-OV3 (0.92 +/- 0.17 pg/mg of protein) but not in the normal ovary and placenta. Two of two extract samples from individual cases evoked dose-dependent phosphoinositide breakdown in rat granulosa cells similar to that caused by authentic gonadotropin-releasing hormone. Gonadotropin-releasing hormone messenger ribonucleic acid was detected in two of two mucinous cystadenocarcinoma specimens, one of one serous cystadenocarcinoma, and SK-OV3 cells but not in the dysgerminoma, mucinous cystadenoma, and normal ovary and placenta. The demonstration of gonadotropin-releasing hormone and its messenger ribonucleic acid raises the possibility that gonadotropin-releasing hormone may play an autocrine regulatory role in the growth of ovarian carcinoma.American Journal of Obstetrics and Gynecology 10/1993; 169(3):605-10. · 3.88 Impact Factor