TP53 and colorectal cancer: Importantly, the proapoptotic BH3-only protein PUMA, a downstream target of p53 and direct activator of apoptosis, was significantly upregulated specifically by the combination of alkannin and olaparib (Figure 5A, Supplementary Figure S5A), consistent with that the SW480 and SW1116 colorectal cancer cells have normal p53 function (Rochette et al., 2005; Leroy et al., 2014).