Overexpression of bcl-2 protects hepatoma cell line HCC-9204 from ethanol-induced apoptosis.

Objective To investigate the effect of overexpression of bcl-2 on ethanol-induced apoptosis of primary hepatocellular carcinoma ( HCC) cells. Methods The retrovirus expression vector pDOR-SB containing human bcl-2 cDNA was introduced into a human HCC cell line HCC-9204 by liposome-mediated transfection, pDOR-transfected and non-transfected HCC-9204 cells were used as controls. The expression of Bcl-2 protein by transfected HCC-9204 cells was detected by the immunohistochemical method. Then the cells were cloned with the limited dilution method continually until a monoclonal cell strain whose positive rate of Bcl-2 protein was 100% detected by flow cytometry was obtained. The killing rates of cells were detected by Methabenzthiazuron assay after the treatment of 6% ethanol for 6 h. The extent of apoptosis was analyzed by transferase-mediated dUTP nick end labeling (TUNEL) staining and flow cytometry. Results Most of the pDOR-SB-transfected cells demonstrated Bcl-2 positive signals, while no signal was found in the controls. The positive rate of Bcl-2 protein detected by flow cytometry in the obtained monoclonal cell strain, which was named HCC-bcl2, was 100% after the cells had been cloned 3 times continually. The killing rate, TUNEL index and the scale of sub-G 1 apoptotic peak in HCC-bcl2 cells were all significantly lower than those in the control cells. Conclusion Overexpression of Bcl-2 protein suppresses ethanol-induced apoptosis of the HCC cell line HCC-9204.