Cytoplasmic p21 induced by p65 is necessary to prevent the activation of procaspase-3 in PANC1 cell. Cells were transiently transfected with or without over-expression of p65 and p65-targeted shRNA followed by DOX treatment (2 μg/ml) for 24 h. (A) The level of p65 protein was detected by Western blotting. (B) Cell survival was examined by CCK8 kit. Error bar indicates the standard error of the mean of three independent experiments. (C)The nuclear or cytoplasmic p21 protein (above) and pro-caspase-3 or active caspase-3 (bottom) were detected by Western blotting. GAPDH was used as controls.