A. Assessment of p-DNA-PKcs/DNA-PKcs expression in human glioma cell lines by immunoblotting. Temozolomide (TMZ) IC50 values were presented in right table. B. siRNA-mediated knockdown of DNA-PKcs reduced glioma cell lines U87 and M059K proliferation. Immunoblotting confirmed the knockdown efficacy, and cell growth curve was measured by MTS assay. C. Pharmacologic characteristic of KU0060648 on p-DNA-PKcs inhibition following 6-hour incubation in U87 and M059K cells (left). Proliferations of two cell lines were investigated by MTS assay after 72-hours treatment (right). D. TMZ IC50 of U87 and M059K in the absence or presence of KU0060648. Two cell lines were incubated for 3 days in a range of concentrations of TMZ with or without of 1 or 10 μM KU0060648 and IC50 value was then calculated by MTS assay (Bars, SD; ★, p < 0.05; ★★, p < 0.001, one-way ANOVA test). E. Colony formation assay evaluating the growth of U87 and M059K cells in treatment of TMZ (100 μM) and KU0060648 (1 or 10 μM) either alone or in combination for 14 days. Cells were stained with 0.1% crystal violet (Bars, SD; ★, p < 0.05; ★★, p < 0.001; one-way ANOVA test).