Effects of X-ray irradiation on the cell cycle of gallbladder cancer cell line GBC-SD

Objectives To observe the effects of X-ray irradiation on the growth and the cell cycle of gallbladder cancer cell line GBC-SD. Methods X-ray irradiation with series dosages of 0 Gy,5Gy,10Gy and 20Gy were respectively administrated to the GBC-SD cells cultured in vitro. The cell growth and cell cycle were detected by MTT assay and flow-cytometry, respectively. Results The growth of gallbladder cancer cells was inhibited after exposure to a high dose of X-ray, which was demonstrated time-dependent and dose-dependent patterns. The results of flow-cytometry also demonstrated that the proportions of cells in G0-G1 and S stages were decreased at 24 hours after radiation, while G2-M stage cells were increased. In contrast, the proportions of cells in G0-G1 stage was increased, and the S and G2-M stages were decreased at 72 hours after exposure. It was also observed that the cell proliferation was induced after low dose X-ray exposure, which was demonstrated as increased proportions of cells both in S and G2-M stages. Conclusions The therapeutic effects of X-ray irradiation could be enhanced by dose escalation. The potential mechanism might be associated with the changes in cell cycle and cell growth.