Effect of M-CPA on the repair of IR-induced DNA damage. (A, D, and G) Single-strand breaks were analyzed by comet assay. The percentages of damaged DNA were averaged from at least 100 nuclei (mean ± SEM). Double-strand breaks were visualized by 53BP1 staining: Miapaca-2 (B&C), Panc-1 (E&F), and HPSC (H&I). Treatment doses: radiation = 10 Gy, M-CPA = 10 μM. Significant differences are denoted by * (p < 0.05).