DNA-PK and ATR are dispensable for cell survival after DNA damage by CNDAC. (A) Glioma-derived cell lines M059-K (●, wild-type) and M059-J (▴, DNA-PKcs-deficient) were incubated with a range of concentrations of CNDAC for 24 hours, and colonies were stained and quantitated after 10 days. (B) HCT116 cells and ML-1 cells, both p53 wild-type, were preincubated with NU7441 at indicated concentrations for 1 hour, followed by various concentrations of CNDAC for additional 24 hours. After washing, HCT116 cells were incubated for 7 to 8 days, and colonies were scored by GelCount; ML-1 cells were counted and distributed into methylcellulose to form colonies in 9 days. (C) CHO lines xrs6 (▴, Ku80-deficient) and xrs6-hamKu80 (●, Ku80-repleted) were incubated with a range of concentrations of CNDAC for 24 hours, and colonies were stained and counted after 6 days. (D) Human fibroblast lines 1BRhTERT (●, wild-type control) and F02-98hTERT (▴, ATR-Seckel) were exposed to different concentrations of CNDAC for 24 hours, and colonies were scored in 10 days. Representative data of 3 independent experiments are shown. All points are mean ± SD of triplicate samples.