Exogenous expression of p21WAF1/CIP1 exerts cell growth inhibition and enhances sensitivity to cisplatin in hepatoma cells

The effects of exogenous expression of p21WAF1/CIP1 in hepatoma cells were examined. Two stably p21WAF1/CIP1-transfected clones and one clone transfected with expression vector only were used for study. Introduction of p21WAF1/CIP1 resulted in significant cell growth inhibition, and the magnitude of the cell growth inhibition in these transfected cells was proportional to the level of p21WAF1/CIP1 protein expressed. Exogenous p21WAF1/CIP1 expression also significantly enhanced chemosensitivity to cisplatin. In addition, apoptosis occurred earlier in cells transfected with p21WAF1/CIP1 after cisplatin treatment. These findings raise the potential that forced upregulation of p21WAF1/CIP1 in hepatocellular carcinoma (HCC) may reduce the doses of cisplatin to achieve similar responses and suggest the possible use of p21WAF1/CIP1 in HCC treatment.