FIGURE 4.

TAT-crmA inhibits activation of the intrinsic apoptotic pathway in vitro. A, changes in mitochondrial membrane potential (ΔΨ) of untreated, 2.5 μm staurosporine-treated (2 h), and 100 μm etoposide-treated (24 h) Jurkat cells. Induction of apoptosis was significantly reduced in both staurosporine-treated and etoposide-treated cells after incubation with 500 nm TAT-crmA fusion protein. B, activation of caspase-9 in Jurkat cells by stimulation with 10 μm doxorubicin for indicated times with or without treatment with 500 nm TAT-crmA. The band at 37 kDa shows cleaved caspase-9, which was not detectable in the untreated control. In contrast to cells stimulated with doxorubicin alone, TAT-crmA-treated Jurkat cells did not activate caspase-9 after 12 h. 6 and 9 h after doxorubicin stimulation active caspase-9 was only weakly detected in fusion protein-treated cells.