Suppression of the activation of caspase-3 by caspase-8 inhibitor in JPX-9 cells during apoptotic process induced by NF-κB inhibitors. CdCl₂-untreated JPX-9 cells were cultured with or without NF-κB inhibitors (PDTC, NAC, or LLL-CHO) in the presence or absence of caspase-8 inhibitor Z-IETD-FMK for 24 hours. After incubation, the expression of pro-caspase-3 was determined as described in the text. Note that the decrease of pro-caspase-3 expression, which indicates caspase-3 activation, in JPX-9 cells induced by NF-κB inhibitors is almost recovered by the addition of Z-IETD-FMK. Results are representative examples of 4 similar experiments.