Figure 4.

Inhibition or deficiency of caspase-8 prevents cell death induced by combined TRAIL+ATO treatment. (A) Cells were treated with TRAIL (Jurkat: 50 ng ml⁻¹, ML-1: 10 ng ml⁻¹, K562: 250 ng ml⁻¹), ATO (500 ng ml⁻¹) or both in the presence or absence of IETD.fmk (20 μM). Cell death was measured by flow cytometry after annexin V staining. Results are represented as average cell death ±s.d. of three independent experiments. (B) Caspase-8-expressing (WT) and caspase-8-deficient (C8^def) Jurkat cells were treated with increasing doses of ATO with or without TRAIL (50 ng ml⁻¹). Viability was measured by MTT assay. The graph shows the average of two independent experiments ±s.d.