Overexpression of dominant-negative FADD in BJAB cells does not impair drug-induced processing of caspase-3, caspase-8, DNA fragmentation, and mitochondrial activation.

Mock- or dominant-negative FADD (FADDdn)-transfected BJAB cells were either left untreated (Co) or were incubated with 0.1 μg/mL Taxol (T) or 1 μg/mL epirubicin (E) for 48 hours. Then Western blot analyses were performed with antihuman caspase-3 (A) and antihuman caspase-8 antibodies (B). Positions of molecular mass markers are indicated at the left. Arrows indicate the positions of procaspase-3 (*), the 17-kd active subunit of caspase-3 (**), procaspase-8 (#), and the 18-kd active subunit of caspase-8 (##). The experiments were repeated and yielded similar results. Additionally, DNA fragmentation (C) and mitochondrial permeability transition (D) in drug-treated BJAB cells were measured as described in “Materials and methods.” Values are given as percentage of specific apoptosis ± SD (n = 3) and as percentage of cells with low ΔΨm ± SD (n = 3), respectively.