Effects of octylphenol on apoptosis of MCF-7 and expression of Bcl_2 and caspase 3

[Objective] To observe the effect of octylphenol (OP) on apoptosis of MCF-7 breast cancer cells. [Methods] Flow cytometry, TUNEL(terminal dUTP nick-end labeling) assay, DNA fragment percent analysis, immunofluorescence by flow cytometry and fluorescent quantitative PCR were used to measure the changes of apoptosis of MCF-7 breast cancer cells and expressions of Bcl2, Bax and caspase 3 when MCF-7 cells were treated with OP. [Results] When MCF-7 cells were treated with 8 , 16 μmol/L of OP for 48 h, the percent of positive TUNEL cells and DNA fragments increased. The percentages of apoptosis were (6.6±1.32) and (16.3±3.48), respectively [(4.3±1.18) in control]. Fluorescence value of Bcl2 was (63.5±5.84) and (30.3±2.49), respectively [(57.2±4.07) in control]. The Bcl2 mRNA expression significantly increased when MCF-7 cells were treated with 4 μmol/L of OP. Treated with 16 μmol/L of OP, the Bcl2 mRNA expressions decreased, Bax and caspase 3 mRNA expressions increased. [Conclusion] Treated with 8 and 16 μmol/L of OP, the apoptosis of MCF-7 cells and DNA fragments percentage increase, which may be caused by up-regulation of Bax and caspase 3 expression, down-regulation of bcl2 expression in MCF-7 breast cancer cells.