Fig. 7

MGMT inhibition increased the cytotoxicity of PARP inhibitor in NPC cells. The survival rates of a HONE-1 and b TW01 cells were examined using the clonogenic assay. The percentages of apoptotic cells in c HONE-1 and d TW01 cell samples were analyzed through flow cytometry after costaining the cells with FITC-conjugated annexin V and PI. The γ-H2AX expression of e HONE-1 and f TW01 cells was investigated using Western blot analyses. Representative histograms indicated the percentages of colony formation and apoptosis cells (annexin V–positive cells). The tested cells were exposed to O6BG (60 μM), olaparib at indicated concentrations or combination treatment for 24 h, and then analyzed for colony formation, apoptotic cell proportion, and γ-H2AX expression. Experiments were performed at least three times. Bar values are presented as mean ± SD. *P < 0.05