Caspase-8 activation in MiTMAB treated cells occurs downstream of caspase-9/3 activation. G2/M synchronized HeLa-Bcl-2 cells were treated with MiTMABs and controls as described in the legend to Figure 5. Following an 8 h exposure to MiTMABs, lysates (prepared in duplicate) were immunoblotted for caspase-8. In contrast to HeLa cells (Figure 3), cleaved caspase-8 was not observed in HeLa-Bcl-2 cells treated with MiTMABs. Lysates prepared from UV treated HeLa and HeLa-Bcl-2 cells were used as a positive control. β-actin served as a loading control.