Correspondingly, staining with the fluorescent probe JC-1 showed a profound dissipation of mitochondrial membrane potential (Figure 5C, Supplementary Figure S5C), and Western blot analyses revealed a significant increase in the levels of activated caspase 3 and cleaved PARP (Figure 5D, Supplementary Figure S5D), in the SW480 and SW1116 cancer cells treated by the combination of 1.5 or 0.75 μM alkannin and 10 μM olaparib for 12 h. This evidence concerns the gene PARP1 and cancer.