Co-treatment with TNFα and FasL induces cell death in SK-N-AS cells. A. SK-N-AS cells were left untreated (UT) or treated for the indicated times with 100 ng/ml Fc:hFasL, 100 ng/ml TNFα, or both. Cell death was assessed by Hoechst staining. Right images are representative of nuclear staining after 24 h of treatment. Scale bar, 20 μm. B-C. Caspase activity assay in SK-N-AS cells left untreated (UT) or treated for 8 h with 100 ng/ml TNFα, 100 ng/ml Fc:hFasL or both incubating with Z-IETD-Afc to measure caspase-8 (B) or Ac-DEVD-Afc to measure caspase 3/7 activity (C). D. Cell death assay in SK-N-AS cells treated or not (UT) for 24 h with 100 ng/ml TNFα, 100 ng/ml Fc:hFasL, or both in the presence of the caspase-8 inhibitor (50 μM IETD) or the pan-caspase inhibitor (10 μM QVD). Cell death was assessed by Hoechst staining *p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001.