Fig. 2. MGMT downregulation is required for TMZ–POH’s cytotoxicity.

a A549 and SPC-A1 cells were treated with 0, 50, 100 μM TMZ–POH for 48 h with or without presence of 25 μM O⁶-BG, respectively, and then subjected to MTT assay, DMSO acted as the control. Absorbance value was calculated and standardized to DMSO group. b H520 cells was infected by Ad-MGMT or control for 24 h followed by 100 μM TMZ–POH treatment for 48 h. Cell viability was detected by MTT assay. c A549 and H460 cells were treated with 0, 50, 100 μM TMZ–POH for 48 h with or without presence of 25 μM O⁶-BG, respectively, and then subjected to apoptosis assay. d H520 cells was infected by Ad-MGMT or control for 24 h followed by 100 μM TMZ–POH treatment for 48 h, and then subjected to apoptosis assay. The results shown are means ± SD; **p < 0.01; ***p < 0.001