PARP1 and glioblastoma: Consistent with our previous observations that amiloride promotes the caspase-independent death of cultured human glioblastoma cells [13], [14], we observed that amiloride does not induce PARP and caspase-7 cleavage in MDA-MB-231 breast tumor cells, and that co-incubation with the caspase inhibitor z-VAD-fmk does not significantly attenuate the cytotoxicity of amiloride (Figures 4A and 4B).