Bid depletion abrogates the death receptor-mediated apoptotic pathway.

<p>Control and HeLa Bid kd were pre-incubated with the pan-caspase inhibitor zVAD-fmk (100 µM) for 1 h followed by treatment for the specified times with CHX (1 µg/ml) in combination with an agonistic Fas antibody or recombinant TRAIL at the indicated concentrations. Controls were treated with vehicle. A, B) Caspase-3 like activity was measured by cleavage of the fluorogenic substrate Ac-DEVD-AMC. Data are means+/−SD from n = 3 separate experiments. # p<0.05 difference from control cells (Ctrl). C, D) Cells were treated as indicated and lysates were subjected to Western blotting with a polyclonal caspase-3, a monoclonal Poly-ADP-Ribose Polymerase (PARP) antibody and a monoclonal α-tubulin antibody. E, F) Cells were treated as indicated and apoptosis was assessed by flow cytometric evaluation of Annexin-V FITC conjugated binding to phosphatidylserine in non-permeabilized cells. Data are means+/−SD from n = 3 separate experiments. # p<0.05 difference from control cells (Ctrl).