[Proliferation inhibition and apoptosis onset in human ovarian carcinoma cell line SKOV3 induced by Genistein]

Abstract

Background & objective: It was reported that Genistein possess inhibitory effects on various carcinomas. But the report on the effects of Genistein on human ovarian carcinoma was rare. This study was aimed to investigate the proliferation inhibition and apoptosis onset in human ovarian carcinoma cell lines SKOV(3) induced by Genistein and to discuss its antitumor mechanism.

Methods: Inhibitory effect of Genistein on SKOV(3) proliferation was tested by MTT method. Apoptotic cell and apoptotic bodies were observed by acridine orange/ethidium bromide(AO/EB) staining and electron microscope (EM). Cell apoptosis percentage and cell cycle phase distribution were measured by flow cytometric assay (FCM). The characteristic DNA ladders of apoptosis were determined by agarose gel electrophoresis (AGE). The expression of proliferation and apoptosis associated proteins and their mRNA were determined using immunocytochemistry and RT-PCR.

Results: A time- dependent and dose-dependent proliferation inhibition of Genistein was demonstrated in SKOV(3); the prominent inhibitory concentrations were 20 micromol/L and 40 micromol/L (P< 0.01) and the 72(nd) hour was the most apparent phase (P< 0.01). The growth inhibition rates of the cancer cells reached 72.07% and 74.93%. A G(2)/M cell cycle arrest was induced in SKOV(3) exposed to 20 micromol/L Genistein. The characteristic morphological changes of apoptosis were observed by AO/EB staining and EM in SKOV(3) exposed to Genistein. The apoptosis rate was highest at 20 micromol/L concentration, reached 23.7%. DNA ladder appeared by AGE. The expression of bcl-2 mRNA was decreased, p21(WAF1/CIP1) and bax mRNA was increased (P< 0.05), the expression of PCNA, Bcl-2,and cyclin B1 protein were decreased, Bax and p21(WAF1/CIP1) protein were increased in SKOV(3) exposed to 20 micromol/L Genistein for 48 hours (P< 0.01).

Conclusion: Genistein could inhibit proliferation and induce apoptosis in ovarian carcinoma cell lines SKOV(3). Its inhibitory effect appears to be due to the up-regulation of p21(WAF1/CIP1) mRNA and protein expression, down-regulation of PCNA and cyclin B1 protein. The onset of apoptosis in ovarian carcinoma cell is related to the up-regulation of bax and down-regulation of bcl-2 in mRNA and protein level induced by Genistein.