BCL2 and cancer: As an alternative approach, we treated cells with QVD-OPh, S63845 and ABT-737 by combined inhibition on pan-caspase, myeloid leukemia 1 (MCL-1) and B-cell lymphoma xL (BCL-xL)/BCL-2/BCL-w respectively, as previously reported for inducing mitochondrial apoptosis and subsequent mtDNA release in cancer cells and primary mouse embryonic fibroblasts (MEFs) [50–52,71,72].