Analysis of apoptotic cascade. A: Activity of caspase-8 and caspase-9 in 1B6 and 8863 IFN-producing (LCIFNSN) and control-transduced (LXSN) cells at 24 hours after cisPt administration as assessed by colorimetric assay. B: Caspase-9 activity in 1B6 cell lines [parental, treated or not with exogenous CIFN, control-transduced (LXSN), and IFN-producing (LCIFNSN)] at 24 hours after cisPt addition, with or without LEHD-CHO caspase-9 inhibitor. C: Percentages of apoptotic cells obtained by annexin V/propidium iodide double staining in the presence or absence of LEHD-CHO and DEVD-CHO, caspase-9 and caspase- inhibitors, respectively.