Stable overexpression of exogenous c-FLIP
protects cells from 17-AAG- or GA-induced caspase activation and growth inhibition in human NSCLC cell lines. (A), H157 cells stably expressing lacZ (H157-lacZ) and c-FLIPL (H157-c-FLIPL) were treated with the indicated concentrations of 17-AAG or GA for 48 h and then the cells were subjected to Western blot analysis for detection of caspase activation and PARP cleavage. (B), H157-lacZ and H157-c-FLIPL cells were cultured in the 96-well plates and then treated with the given concentrations of 17-AAG or GA for 48 h, then the cell number was estimated by SRB assay to determine the cell survival. Differences between groups are evaluated by Student’s t-test. Columns, mean of triplicate treatments; bars, ± SD. The statistical differences between the two treatments were analyzed by two-sided unpaired Student’s t tests (*P<0.05; **P<0.01; *** P<0.001).