CASP9 and cancer: To further confirm that the mechanism of cell death from bicistronic expression of p14 and tBID was through both the intrinsic and extrinsic apoptotic pathways, we tested inhibitors for Caspase-8, Caspase-9, and Caspase-3, each at their IC50 (2 μM), in PANC1 cancer cells transfected with Ad-pCMV-p14-tBID (Supplementary Figure S2C).