ABSTRACT
Objective:To investigate the mechanisms of genistein (GEN) affecting the chemosen- sitivity of human breast cancer cell line MDA-MB-453 to paclitaxel (PTX) in vitro. Method:HER2/neu- overexpressing breast cancer cells MDA-MB-453 were treated by GEN, PTX alone or combined in vitro. Cell cycle was measured by flow cytometry. The expression of HER2/neu protein was observed by immunocytochemistry and. Akt, p-Akt, cyclin B1 and CDK1 protein by Western blot. Results:Cell cycle of MDA-MB-453 cells was blocked at G1/S after treatment of GEN, while at G2/M after treatment with PTX alone. Both GEN and PTX did not change the expression of HER2/neu, total Akt and CDK1 in MDA-MB-453 cells, but GEN significantly decreased p-Akt and cyclin B1 level, and PTX obviously increased cyclinB1 level. GEN antagonized the effects of PTX on level of cyclin B1 protein and blockage of G2/M in MDA-MB-453 cells after treatment with GEN and PTX in combination. Conclusion:The antagonism effects of GEN on the increase of cyclin B1 and blockage of G2/M induced by PTX may be one of the mechanisms of GEN affecting the chemosensitivity of MDA-MB-453 cells to PYX.