TWEAK-induced apoptosis in PC-3 cells is dependent on caspase activation. A)

Inhibition of caspases with pan-caspase inhibitor zVAD (20 µM) prevented apoptosis in PC-3 cells stimulated with TWEAK/TNFα/IFNγ for 24 hours. Apoptosis was assessed by flow cytometry of DNA content. Mean (±SD) of three experiments. *p<0.002 vs control; #p<0.001 vs TWEAK/TNFα/IFNγ alone. B) Incubation with TWEAK or TWEAK/TNFα/IFNγ resulted in the appearance of active caspase-3 fragments (arrows, representative Western blot), C) and this is barely observed in presence of 10% FBS. D) Active caspase 3 immunofluorescence in PC-3 cells treated with TWEAK/TNFα/IFNγ. Confocal microscopy. Active caspase 3 in green and propidium iodide in red. (Magnification 320x). Pictures representative of three independent experiments.