ATR and cancer: In the SW480 and SW1116 cancer cells, 3 h of treatment by the combination of 0.75 μM alkannin and 10 μM olaparib induced a marked increase in the levels of phosphorylated Chk1, Chk2 and p53 (Figure 5A, Supplementary Figure S5A), demonstrating activation of both the ATM-Chk2 and the ATR-Chk1 DDR pathways (Ciccia and Elledge, 2010).