Fig. 1

The ATR inhibitor VE-821 radiosensitized human tumor cells irradiated with high LET carbon ions. HeLa, U2OS, and 1BR-hTERT cells were pre-treated with 1 μM VE-821 or DMSO for 1 hour before irradiation, and were irradiated with 1, 2, 3 Gy of carbon ions or 2, 4, 6 Gy of X-rays. At 8 hours (a) or 24 hours (b) after irradiation, cells were plated on cell culture dishes to form colonies. Colonies containing more than 50 cells were counted as surviving cells. Error bars represent standard error of the mean (SEM) of at least three independent experiments. Curves with *show statistically significant data (p <0.05) when compared with control curves with DMSO only