FIG. 3.

CRAd(E3±)-induced cell death is not mediated by caspases and is not dependent on the activation of the mitochondrial apoptotic pathway regulated by Bcl2. H460 cells were infected at an MOI of 25, and cell extracts were made at different times postinfection and subjected to Western blotting. As a control, H460 cells were treated with agonistic Fas Abs in combination with CHX (Fas). (A) The expression levels of unprocessed procaspase-9, -8, and -3 were assessed together with the cleavage of caspase substrate PARP. (B) Bcl2 and BclXL expression was also determined. (C) CRAd(E3+)-induced cell killing in H460-derived stable transfected cell lines overexpressing antiapoptotic Bcl2 and BclXL or the caspase-inhibitor XIAP when compared to the empty vector controls H460\PEFPGK3 and H460\pcDNA3 was studied. Different MOIs were used, and WST-1 activity was measured at 4 days postinfection. Similar results were obtained for CRAD(E3−). (D) Cotreatment with the broad caspase inhibitor zVAD-fmk failed to protect H460 cells from CRAd(E3±)-induced cell death, whereas it was effective in protecting against apoptosis induced by FasL+CHX cells that served as a positive control. Values are means ± standard deviation of three experiments.