IL-1β sensitizes primary murine hepatocytes to FasL-induced caspase-3/-7 activity despite partially protecting from apoptosis.

<p>(A) Caspase-3/-7 activity determined by a fluorogenic DEVDase assay of cells treated with IL-1β (20 ng/ml), FasL (50 ng/ml), or IL-1β + FasL for the indicated times. Cells were pre-treated with IL-1β for 12 or 24 h followed by 6 h FasL stimulation. (B) Detection of DNA-fragmentation by cell death ELISA in hepatocytes treated as described above. (C) MTT viability assay of cells treated with IL-1β, FasL or both for the indicated times, in the presence or absence of pre-incubation with 25 µM of the pan-caspase inhibitor Q-VD-OPh 30 min prior to cytokine stimulation. Values are referred to untreated controls and represent 12 independent experiments ± s.d. except for treatment with IL-1β n = 4 (*p<0.05, ***p<0.001, IL-1β + FasL versus FasL-treated cells, ^###p<0.01, IL-1β + FasL versus QVD + IL-1β + FasL).