Figure 7

Stimulation of rhTRAIL- and agonistic DR4 antibody-induced but not agonistic DR5 antibody-induced apoptosis by IFN-γ. A: Survival (%) of SW948-TR cells after continuous incubation with rhTRAIL, agonistic DR4 or DR5 antibody in combination with different concentrations of IFN-γ. B: Apoptosis assay of SW948-TR after 48 h incubation with rhTRAIL, agonistic DR4 or DR5 antibody in combination with various concentrations of IFN-γ. C: Apoptosis assay in SW948-TR after 48 h incubation with 1000 U/ml IFN-γ. Cells were then incubated with 10 μg/ml antagonistic anti-DR4 (αDR4), anti-DR5 (αDR5) antibodies, both (αDR4/5) or IgG1 control for 1 h before 4-5 h rhTRAIL treatment (0.1 μg/ml). D: Western blot analysis of caspase 8 activation in SW948-TR cells. The cells were pre-incubated for 48 hours with 1000 U/ml IFN-γ, then either left untreated or exposed for 4-5 additional hours with rhTRAIL (0.1 μg/ml) before harvest. E: Western blot analysis of caspase 8 activation in SW948-TR cells. The cells were pre-incubated for 48 hours with 1000 U/ml IFN-γ, then either left untreated or exposed for 4-5 additional hours with agonistic DR4 antibody (50 nM) or agonistic DR5 antibody (50 nM) before harvest.