Time kinetic study of activation in caspase-8 and caspase-3 during PDTC-induced apoptosis. CdCl₂-untreated JPX-9 cells were cultured for indicated hours in the presence of 50 μmol/L of PDTC. After incubation, the expression of pro-caspase-8 (A) and procaspase-3 (B) was examined by Western blotting. Note that the decrease of pro-caspase protein expression was found at 24 hours incubation of JPX-9 cells with PDTC, whereas that was not determined at 3 hours incubation of the cells with PDTC in which nuclear NF-κB activity had already been suppressed. Results are representative of 4 experiments.