Fig. 5

The combination of BKM120 and TH588 synergistically induces oxidative DNA damage and apoptosis. a Comet assay of U251 cells following treatment with BKM120, TH588 or the combination for 24 h. H2O2 was used as a control. b Quantification of comet tail moment. Tail moment, calculated as  % DNA in the tail multiplied by the tail length. Values represent the average ± SD from three independent experiments (> 25 comets per experiment, **P < 0.01). c Flow cytometry assay of H2AX phosphorylation in U251 cells following treatment with increasing concentrations of TH588 for 24 h. d Quantification of γ-H2AX-positive cells from B (*P < 0.05, **P < 0.01). e Flow cytometric analysis of  % apoptotic U251 cells (stained by annexin V/PI) following BKM120, TH588 or combination pretreatment for 24 h. f Quantification of apoptotic cells from f; shown is the average ± SD, n = 3 (*P < 0.05, **P < 0.01). g U251 cells treated with BKM120, TH588 or a combination of both for 48 h, and then subjected with co-staining with annexin V and PI. Cells were observed under a fluorescent microscope and representative photos were given. Scale bars = 0.2 mm. h U251 cells received treatment of BKM120,TH588 or a combination of both for 48 h were immunoblotted with antibodies of cleaved caspase-3 and GAPDH