Objective To explore the inhibiting effect of superoxide dismutase (SOD) on the growth of hepatocellular cancer cell line HepG2. Methods By gene transfer technique, hepatocellular cancer cells (HepG2) were transfected with a retroviral vector containing human CuZnSOD cDNA. The elevated SOD gene expression of the transfected cells was compared with the parental and neo control cells. Results Compared to the control cells, cancer cells transfected with SOD gene showed an inhibited cell growth, a reduced number of cells in S phase and decreased clone forming ability in soft agar, as well as a smaller tumor size formed in nude mice.Conclusion The overexpression of CuZnSOD gene could, to certain extent, suppress the cell growth of hepatocellular cancer cell line HepG2.

Objective To study the effects of the p16 gene on tumor cell growth inhibition and cell cycle arrest. Methods The recombinant retroviral vector pLp16SN was constructed by cloning the human p16 cDNA into the retroviral vector pLXSN. Retroviruses with or without the p16 gene were obtained by transfecting pLp16SN and pLXSN vectors into PA317 cells. Bcap-37 human breast cancer cells were infected with these retroviruses followed by selection with G418. The expression of p16 was detected by Northern and Westem blots. Cell biological characteristics, including cell growth rate, cell cycle and tumorigenesis in nude mice were assessed.Results Both mRNA and protein expression of p16 in Bcap-37 cells transfected with retroviral vector containing the p16 gene were much higher than that in Bcap-37 cells transfected with empty vector or parental Bcap-37 cells. Cell overexpressing the p16 gene exhibited a slower rate of growth, a higher percentage of cells in the G1 phase, and smaller tumors in nude mice, compared with parental Bcap-37 cells and cells transfected with empty vector.Conclusion Overexpression of the p16 gene could suppress the growth of Bcap-37 breast cancer cells by arresting the cell cvcle at the G1 to S-phase.