[The effect of progesterone on proliferation and apoptosis in ovarian cancer cell].

OBJECTIVE: To investigate the regulatory effect of progesterone on proliferation and apoptosis in ovarian cancer cell line HO8910 in vitro. METHODS: Ovarian cancer cell line HO8910 originated from human ovarian serous cystadenocarcinoma was cultured in vitro. Two groups were set up: study group (progesterone in different concentrations) and control group without progesterone. Cell proliferation was measured by 3-(4, 5-dimethylthiazol-z-yl)-2,5-dipheny tetrazolium blue (MTT) colorimetric assay. Cell cycle and apoptotic percentage were detected by flow cytometry, morphological changes of apoptotic cells were observed by light and electron microscopy, and apoptotic cells were quantitatively determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). In addition, expression of intracellular bcl-2 protein was analyzed by flow cytometric indirect immunofluorescent technique. RESULTS: Progesterone of 1 x 10(-7)-1 x 10(-5) mol/L inhibited HO8910 cell growth significantly in a dose-dependent manner (P < 0.01). After treatment with progesterone, the enhanced G0/G1 arrest was accompanied with the enhanced apoptotic peak and percentage, as well apoptotic cells were found more than those in control group (P < 0.05). By light and electron microscopy, there were many morphological characteristics of apoptosis including compaction and margination of nuclear chromatin, nuclear fragments, and apoptotic bodies. Analysis on expression of intracellular bcl-2 protein showed that progesterone could down-regulate bcl-2 protein and at concentration of 1 x 10(-5) mol/L it could almost block bcl-2 expression. CONCLUSIONS: It is suggested in the present study that progesterone can inhibit the proliferation of epithelial ovarian cancer cells in vitro and there is an accordant dose-response relationship. Its anticancer effect seems to be due to induction of apoptosis which maybe a result of down-regulation of the anti-apoptotic protein bcl-2.