The effect of the ATM inhibitor AZD0156 on the radiosensitivity of human breast cancer and lung fibroblast cells.

Aims: To evaluate the effect of the combination of irradiation and AZD0156 on apoptosis, cell cycle progression, and clonogenic survival in human breast cancer and fibroblast cells. Methods and Material: Estrogen receptor-positive breast cancer cell line MCF-7 and healthy lung fibroblast cell line WI-38 were obtained. Following employing proliferation analysis, cytotoxicity analysis was done to calculate the IC50 values of AZD0156 in MCF-7 and WI-38 cell lines. Following the application of AZD0156 and irradiation, flow cytometry analysis was performed for evaluating cell cycle distribution and the extent of apoptosis. Plating efficiency and surviving fraction were calculated for the clonogenic assay. Statistical Analysis Used: SPSS Statistics for Windows, Version 17.0. (SPSS Inc. Chicago) and GraphPad Prism Version 6.0 for Windows (GraphPad Software, San Diego, California USA) softwares were used to analyze data. Results: AZD0156 and irradiation dose of 2-10 Gy had no effect on apoptosis on MCF-7 cells. The combination treatment of AZD0156 and 2 Gy, 4 Gy, 6 Gy, 8 Gy, and 10 Gy irradiation induced G0/G1 phase arrest by 1.79, 1.79, 1.50, 1.25, and 1.52-fold compared to the control group, respectively on MCF-7 cell lines. Combination treatment of AZD0156 and each different irradiation dose affected clonogenic survival owing to increased radiosensitivity (p: 0.02). AZD0156 and irradiation dose of 2 Gy, 4 Gy, 6 Gy, 8 Gy, and 10 Gy decreased the cell viability rate of WI-38 cells by 1.05, 1.18, 1.22, 1.04, and 1.05-fold compared to the control group, respectively. No efficacy was detected on cell cycle analysis, and clonogenic survival was not significantly decreased in WI-38 cells. Conclusion: The combination use of irradiation and AZD0156 has improved efficacy of tumor cell-specific cell cycle arrest and decreasing clonogenic survival.