Daidzein Induces Intrinsic Pathway of Apoptosis along with ER α/β Ratio Alteration and ROS Production

BACKGROUND: Low risk of breast cancer is observed among females consuming a moderate quantity of soy throughout their life. The present study was conducted to evaluate the anticancer potential of Daidzein, one of the major Isoflavones in soy using Human breast cancer cells MCF-7. METHODS: MCF-7 were subjected to various doses of Daidzein treatment to determine the IC50 value. Onset of apoptosis was ascertained by AnnexinV assay and caspase 3/7 activity post treatment. Expression of pro-apoptotic protein Bax and anti-apoptotic protein Bcl2 was also assessed to further confirm apoptotic mode of cell death. ROS production post treatment with Daidzein was assessed to ascertain the apoptosis via intrinsic pathway. Expression of ER α and ER β was evaluated by western blot analysis. RESULTS: Human breast cancer cells MCF-7 were found to be sensitive to Daidzein treatment, with an IC(50) value of 50µM. Increased percentage of treated cells stained with Annexin V confirmed apoptosis mediated cell death. Activity of Caspase 3/7 activity was found to be 1.4-fold higher in Daidzein treated cells than control cells, confirming apoptosis. Daidzein caused over expression of Bax and down-regulated expression of Bcl2. There has been an outburst of ROS in Daidzein treated cells indicating that Daidzein induces apoptosis via intrinsic pathway. A decrease in the expression of ER α and increase in levels of ER β has been observed which are conducive indicator of apoptosis. CONCLUSIONS: In conclusion, the present study suggests that Daidzein induces apoptosis in MCF-7 cells by mitochondrial pathway along with lowering the ratio of ER α/β and an outburst of Reactive Oxygen Species(ROS).