CASP8 and breast carcinoma: However, Pledgie-Tracy et al. showed that the activation of apoptosis after a 72 h incubation with 5 μm, 10 μm and 25 μm SFN in triple negative therapy-resistant breast cancer MDA-MB-231 cells was initiated by the induction of Fas ligand, which results in the activation of caspase-8, caspase-3 and poly(ADP-ribose) polymerase (PARP).