ABSTRACT
Objective To study the mechanisms of inhibiting proliferous effect of human breast cancer cell line treated with genistein in vitro. Methods Two human breast cancer cell lines (MCF 7 and MDA MB 231) were cultured in vitro , proliferation of them was measured with MTT method, cell morphology was observed with Giemsa stain, cell cycle and apoptosis rate were measured with flow cytometry and apoptosis was detected in situ. Results Genistein markedly inhibited proliferation of MCF 7 and MDA MB 231 cell line. Typical image of apoptosis was observed in MCF 7 cell line treated with genistein in Giemsa stain:cell condensation, blebs formation on cell surface and pieces of condensed chromatin were scattered along nuclear envelope. The results detected with flow cytometry showed G 1 subpeak before G 1 phase peak (apoptosis peak). Apoptosis rate increased with time of genistein treatment. However, MDA MB 231 cell line treated with genistein did not show apoptosis and apoptosis peak, and quantity of cells at G 2 M phase obviously increased.Conclusion Genistein inhibites proliferation of human breast cancer cell line in vitro through inducing apoptosis or arresting cell at G 2 M phase.\;[