Figure 4: Clonogenic survival curves after 24 hrs (left) or 48 hrs (right) preincubation with CI-1033 before radiation (RT). Dose modifying factors (DMF) at a surviving fraction of 0.2 were determined for each cell line for 24 hr and 48 hr: (A), 1.3 and 1.1 respectively for Gli-6, (B) 0.95 and 1.2 respectively for D384MG, (B) 0.9 and 1.0 for U-251 MG: (C). In all experiments DMSO was used as a control. Error bars show the mean ± SD of at least two independent experiments. P values < 0.05 indicate statistically significant differences between radiation alone and radiation combined with CI-1033.