title: Differential regulation of two forms of gonadotropin-releasing hormone messenger ribonucleic acid by gonadotropins in human immortalized ovarian surface epithelium and ovarian cancer cells.
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.
authors.affiliation: Department of Obstetrics and Gynecology, British Columbia Children's and Women's Hospital, Child and Family Research Institute, University of British Columbia, 2H-30, 4490 Oak St, Vancouver, British Columbia, Canada, V6H 3V5.
authors.forename: Jung-Hye
authors.initials: JH
authors.lastname: Choi
authors.forename: Kyung-Chul
authors.initials: KC
authors.lastname: Choi
authors.forename: Nelly
authors.initials: N
authors.lastname: Auersperg
authors.forename: Peter C K
authors.initials: PC
authors.lastname: Leung
mesh_terms: D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology* / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects*; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics*; D006062:Gonadotropins / Q000494:pharmacology / Q000502:physiology; D006801:Humans; D007986:Luteinizing Hormone / Q000494:pharmacology* / Q000502:physiology; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000378:metabolism; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000378:metabolism; D018013:Receptors, Neuropeptide / Q000819:agonists / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D006062:Gonadotropins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D018013:Receptors, Neuropeptide; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone