ATM and malignant colon neoplasm: The results demonstrated that the p-ATM level was significantly decreased in the PXR-KO LS180 cells transfected with the PXR T432A mutant plasmid compared with that of the wild-type PXR transfection (Figure 3G, lane 6 vs. lane 4), suggesting that the phosphorylation of PXR T432 was pivotal for ATF3-mediated ATM activation upon IR in colon cancer cells.