Bcl-2 and Bcl-xL overexpression but not FADD deficiency blocks proteasome inhibitor-induced apoptosis. (A) WT (▪) and FADD-deficient Jurkat cells (□) were exposed for 24 hours to 1 μg/mL FasL or to 25 μg/mL etoposide (etopo). Thereafter, cells were harvested, and dead cells were quantified by flow cytometry after staining with propidium iodide. (B) WT (,
,
) and FADD-deficient Jurkat cells (
,
,
) were exposed for 24 hours to 0.4 μM epoxomicin (
,
), 0.5 μM MG132 (
,
), or 5 μM lactacystin (
,
). Cell death was determined by flow cytometry analysis of propidium iodide-stained cells. (C-D) Bcl-2 (C)/Bcl-xL (D)-overexpressing Jurkat cells (
,
,
) and respective vector control cells (vec;
,
,
) were stimulated for 24 hours with 0.4 μM epoxomicin (
,
), 0.5 μM MG132 (
,
), or 5 μM lactacystin (
,
). Cell death was determined by flow cytometry analysis of propidium iodide-stained cells. Results are presented as means of duplicates.