Biological effects of heavy ion and X-ray irradiation on lung cancer cells A549

Abstract

Objective To compare the effects of carbon heavy ion and X-ray irradiation on survival fraction,cell cycle,cell apoptosis and expression of DNA-PKcs of A549 lung cancer cells.Methods A549 cells were irradiated by carbon heavy ion and X-ray.Cell survival fraction,cell cycle and apoptosis were analyzed by clonogenic formation assay,flow cytometry and Hoechst 33258 staining,respectively.Real time-PCR was performed to detect the expressions of DNA-PKcs and H2AX mRNA.Results Lower cell survival fraction,more G2/M phase arrest and higher apoptosis rate were detected in the A549 cells exposed to carbon heavy ion than X-ray(t =4.77,14.53,14.54,P ＜ 0.05).Expression of DNA-PKcs was up-regulated after irradiation to carbon heavy ion and X-ray(t =10.91,5.05,P ＜ 0.05).Conclusions Both heavy ion and X-ray irradiations enhance the expression of DNA-PKcs,induce apoptosis through regulating cell cycle arrest,and hence reduce survival of A549 cells.Heavy ion irradiation shows more stronger biological effects than X-ray irradiation. Key words: Heavy ions; X-rays; Apoptosis; DNA-PKcs