Fig. 7. cFLIP_L overexpression in keratinocytes potently inhibits TRAIL-mediated apoptosis. Stably transfected keratinocytes were generated by retroviral infection of either PINCO-control vector or PINCO-cFLIP_L in HaCaT keratinocytes as described in Materials and Methods. Overexpression of cFLIP_L was confirmed using 50 µg protein of total cellular lysates by western blotting and subsequent analysis for cFLIP_L. As control, cell lysates were blotted against anti-procaspase-8 antibody (C15) (A). (B) For functional analysis, cells were seeded in 96-well-plates in duplicates and were stimulated with the indicated concentrations of recombinant TRAIL for 16 hours. The percentage of living cells was normalized to mock-stimulated cells as marked on the y-axis. One of three representative experiments is shown.