Overexpression of bax enhances ethanol-induced apoptosis in hepatoma cells

Purpose To explore the regulative function of pro-apoptotic gene bax overexpression in ethanol-induced apoptosis of primary hepatocellular carcinoma (HCC) cells. Methods The plasmid of bacteriophague expression vector pBK-bax, which contains human bax cDNA, was transduced into HCC cell line HCC-9204 cells with Lipid-mediated gene transfection method, and at the same time the HCC-9204 cells transfected with empty pBK-CMV plasmid and non-transfected HCC-9204 cells were taken as control. The cell clones, into which objective genes had been transfected, were obtained after being screened with G-418. The expression of bax protein in the cells prior to and after transfected with bax or empty vector was detected with immunocytochemical ABC method, image quantitative analysis and Westorn blot. After the above cells were affected by 6% ethanol for 6 h, the killing rates of the cells were detected with MTT method. The degree of apoptosis was detected with TUNEL staining and DNA contents analysis by flow cytometry. Results The G-418-resistant cell clones, which had been transfected with bax or empty vector were obtained by screening continually with G-418 for 2 w after transfection. There was stronger expression of bax protein in the cells transfected with bax gene than in those transfected with empty vector or non-transfected cells. There was no significant difference between the cells transfected with empty vector and non-transfected cells in the expression of bax protein. After the cells were affected by low-concentration ethanol. The killing rate, TUNEL index and sub-G_1 apoptotic peek scale of the bax-transfected cells were all lower than those of the cells transfected with empty vector or non-transfected cells. Conclusions Overexpression of bax protein can enhance low-concentration ethanol-induced apoptosis in HCC-9204 hepatoma cells.