THE MECHANISMS OF PROLIFERATION AND APOPTOSIS IN MCF-7 CELLS BY DIETARY ESTROGENS

Objective: This study was designed to investigate the molecular mechanisms of proliferation and apoptosis by genistein and zearalenone through regulation of mRNA and protein expression of PCNA, bcl-2 and bax in breast cancer MCF-7 cells. Methods: The cells were maintained in DMEM medium with 10% fetal bovine serum. Five days before the beginning of experiments, the cells were seeded in phenol red-free DMEM medium containing 5% charcoal dextran–treated FBS. The cells were harvested and seeded in 6-well culture plates or in 75 ml flacks. After various concentrations of genistein and zearalenone treatments for 72 h, the cells were harvested and mRNA and protein expression of proliferation cell nuclear antigen(PCNA), bcl-2 and bax were detected by reverse transcription-polymerase chain reaction and immunohistochemistry, respectively. Results: At the concentration of 75 μmol/L, GS could significantly down-regulate bcl-2 and PCNA mRNA expression and up-regulate bax mRNA expression, and zearalenone indicated an opposite result. These results were further confirmed by following immunohistochemistry. Conclusion:PCNA, bcl-2 and bax pathway might be involved in cell proliferation and apoptosis events regulated by dietary estrogens genistein and zearalenone in breast cancer MCF-7 cells.