2-Methoxyestradiol, an endogenous estradiol metabolite, differentially inhibits granulosa and endothelial cell mitosis: a potential follicular antiangiogenic regulator.
2-Methoxyestradiol (2-ME) is an estradiol metabolite with antiangiogenic and antitumor activity. It is formed by granulosa cell (GC) catechol-O-methyltransferase activity and is present in the normal follicle at high concentrations. In this unique microenvironment, it may regulate selected cell types via autocrine and/or paracrine action. To assess the possibility that 2-ME or estradiol might exert differential mitotic and/or apoptotic effects on endothelial cells and GCs, we compared their actions on primary cultures of hormone- and/or growth factor-stimulated porcine GCs (pGCs) as well as two types of endothelial cells, primary cultures of porcine endothelial cells (pECs), and a spontaneously transformed rabbit endothelial vascular cell (REVC) line. The 2-ME, but not estradiol, dose dependently suppressed tritiated thymidine ((3)H-T) incorporation into epidermal growth factor (EGF)-stimulated REVCs and EGF/insulin (INS)-stimulated pECs. In contrast, 2-ME did not attenuate incorporation in FSH/INS-stimulated pGCs. It reduced incorporation by approximately 50% in EGF/INS-stimulated pGCs, indicating that responsiveness to 2-ME in normal cells can be modulated by hormone and growth factor treatment. Estradiol was not antimitotic to pGCs. As indicated by 4',6-diamido-2-phenylindole hydrochloride nuclear staining, estradiol was nonapoptotic in either cell type, and 2-ME significantly increased apoptosis of REVCs, but not of pGCs. In a cell migration assay, REVC movement was attenuated by 2-ME, but not by estradiol. In summary, the results show that antimitotic as well as proapoptotic responses to 2-ME vary with cell type and, in the case of pGC antimitotic activity, with the regulatory microenvironment. Thus, they provide a rationale for autocrine and/or paracrine action of 2-ME at its site of production in vivo, and they strongly support the concept of 2-ME as a candidate ovarian angiogenesis inhibitor.
Shang
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Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Konidari
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Schomberg
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DW
D000077584:2-Methoxyestradiol; D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D001011:Aorta; D017209:Apoptosis / Q000187:drug effects; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000494:pharmacology; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology*; D005260:Female; D006107:Granulosa Cells / Q000166:cytology* / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology; D008938:Mitosis / Q000187:drug effects*; D010053:Ovary / Q000098:blood supply; D011817:Rabbits; D013552:Swine; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
D020533:Angiogenesis Inhibitors; D007328:Insulin; D014316:Tritium; D004958:Estradiol; D004815:Epidermal Growth Factor; D000077584:2-Methoxyestradiol; D013936:Thymidine