Apoptosis induced by genistein in esophageal cancer EC-109 cells and its relation to Bcl-2 and Bax

Objective To investigate the effect of genistein in induction of apoptosis of esophageal cancer EC-109 cells and its relation to the expression of Bcl-2 and Bax.Methods MTT assay was used to determine the cell growth inhibitory rate.Transmission electron microscope and TUNEL staining method were used to detect cell apoptosis of before and after the genistein treatment.Immunohistochemical staining and RT-PCR was used to detect the expression of Bcl-2 and Bax.Rusults Genistein inhibited the growth of esophageal cancer EC-109 cells in a dose-and time-dependent manner.Genistein induced apoptosis of EC-109 cells with typical apoptotic characteristics.TUNEL assay showed that after treatment of genistein for 24 to 96 h,the apoptotic indexes were significantly increased with treatment time.Immunohistochemical staining showed that after the treatment with genistein for 24 to 96 h,the positive rate of Bcl-2 proteins was significantly reduced and that of Bax proteins significantly increased with treatment time.RT-PCR showed that after exposed to genistein for 24h,48h,72h and 96h,the density of bcl-2 mRNA decreased progressively and that of bax mRNA increased progressively with exposure time.Conclusion Genistein can induce the apoptosis of esophageal cancer EC-109 cells,which may be mediated by down-regulation of Bcl-2 gene and up-regulation of bax gene.