Restoration of the p16 gene is related to increased radiosensitivity of p16 -deficient lung adenocarcinoma cell lines

To assess the role played by p16 gene expression in the radiosensitivity of human lung cancers, we transferred exogenous p16 genes into p16-deficient H460 and A549 lung adenocarcinoma cell lines and compared the cell survival curve in vitro after irradiation. The surviving fraction of the p16-transfected A549p16 and H460p16 cells that expressed exogenous p16 mRNA or protein was lower than those of the parental and negative control cells. The rapid exit of the p16-transfected cells from the G2/M phase in the cell cycle, both before and after irradiation, possibly contributes to the increased radiosensitivity of our experimental p16-transfected lung adenocarcinoma cell lines. We conclude that exogenous p16 gene may be another important factor controlling the intrinsic cellular radiosensitivity of cancer.