Evaluation of the effect of z-VAD-fmk, z-LEHD-fmk (specific caspase 8 inhibitor), and z-IETD-fmk (specific caspase 9 inhibitor) on TRAIL- and SNP plus TRAIL–mediated cytotoxicity.

After 24 hours of culture, viable cells were counted by trypan blue dye exclusion (A; data are expressed as percentage of His peptide controls) and the percentage of apoptosis was quantitatively evaluated by flow cytometry after PI staining (B). Data represent the means ± SDs of 4 independent experiments performed in duplicate.