title: Cellular mechanisms of growth inhibition of human endometrial cancer cell line by an antagonist of growth hormone-releasing hormone.
abstract: The expression of growth hormone-releasing hormone (GHRH) and its receptors has been demonstrated in peripheral tissues as well as CNS. Recently, the functional splice variant SV1 of GHRH receptor was identified in various human cancers and cancer cell lines. Although antineoplastic activity of GHRH antagonists has been clearly demonstrated, the mechanism of action is incompletely understood. The objective of this study was the investigation of direct anti-proliferative effect of GHRH antagonist MZ-5-156 on HEC-1A human endometrial cancer cell line and the elucidation of underlying mechanisms. RT-PCR revealed the expression of mRNA for GHRH and SV1 of GHRH receptor in HEC-1A cells. MZ-5-156, at concentrations between 10(-7) and 10(-5) M, had a dose-dependent antiproliferative effect on HEC-1A cells, as determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, (MTS) assay. Hoechst 33342 staining and flow cytometric analysis indicated that MZ-5-156, at 10(-6) M, induced apoptosis in HEC-1A cells after 48 h of treatment. Western blot analysis of apoptosis-related proteins demonstrated that treatment with MZ-5-156 (10(-6) M) for 48 h significantly increased the protein levels of Fas, phospho-p53 (Ser46), p53AIP1 (p53-regulated Apoptosis-Inducing Protein 1), and caspase-8, -9, and -3, and decreased the protein level of Bcl-2. These results demonstrate that MZ-5-156 can directly inhibit the proliferation of human endometrial cancer cells, which express mRNA for GHRH and SV1 of GHRH receptor, presumably through the induction of p53-dependent apoptosis coupled with the up-regulation of Fas, phospho-p53 (Ser46), p53AIP1, and caspase-8, -9, and -3, and the down-regulation of Bcl-2.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhao
authors.forename: Tetsu
authors.initials: T
authors.lastname: Yano
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Osuga
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Nakagawa
authors.forename: Hajime
authors.initials: H
authors.lastname: Oishi
authors.forename: Osamu
authors.initials: O
authors.lastname: Wada-Hiraike
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Tang
authors.forename: Naomi
authors.initials: N
authors.lastname: Yano
authors.forename: Koji
authors.initials: K
authors.lastname: Kugu
authors.forename: Andrew V
authors.initials: AV
authors.lastname: Schally
authors.forename: Yuji
authors.initials: Y
authors.lastname: Taketani
mesh_terms: D000231:Adenocarcinoma, Papillary / Q000235:genetics / Q000473:pathology*; D000368:Aged; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D020169:Caspases / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D016889:Endometrial Neoplasms / Q000235:genetics / Q000473:pathology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D019254:Genes, bcl-2; D016158:Genes, p53; D013007:Growth Hormone-Releasing Hormone / Q000037:antagonists & inhibitors* / Q000235:genetics; D006801:Humans; D012333:RNA, Messenger / Q000378:metabolism; D018013:Receptors, Neuropeptide / Q000235:genetics / Q000378:metabolism; D018017:Receptors, Pituitary Hormone-Regulating Hormone / Q000235:genetics / Q000378:metabolism; D017337:Sermorelin / Q000031:analogs & derivatives* / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; C106656:MZ 5-156; D012333:RNA, Messenger; D018013:Receptors, Neuropeptide; D018017:Receptors, Pituitary Hormone-Regulating Hormone; D017337:Sermorelin; D013007:Growth Hormone-Releasing Hormone; D020169:Caspases; C048250:somatotropin releasing hormone receptor