C, Apoptotic assay of H358 and A549 cells treated for 48 h with vehicle (DMSO), AZD 4547 (5 µM) and BI2536 (5nM), in the presence or absence of NAC (5 mM). Data are presented as mean ± SD (n=3). *P<0.05, **P<0.01, ***P<0.001 and ns P＞0.05 by two-way ANOVA with Tukey's multiple comparisons test. 