The cells were harvested at different time point after irradiation. The expressions of proteins were analyzed by western blotting (A). Effect of CGN pretreatment combined with X-ray irradiation on cell cycle distribution in A549 cells (B–H). B, cells treated with 0 μM CGN and 0 Gy X-rays. C, cells treated with 1 μM CGN and 0 Gy X-rays. D, cells treated with 0 μM CGN and 2 Gy X-rays. E, cells treated with 1 μM CGN and 2 Gy X-rays. F, cells treated with 0 μM CGN and 4 Gy X-rays. G, cells treated with 1 μM CGN and 4 Gy X-rays.**P < 0.01 vs. X-ray irradiation alone. All experiments were repeated independently for three times and the typical images were presented.