ATM-deficient lung, prostate and pancreatic cancer cells are acutely sensitive to the combination of olaparib and the ATR inhibitor AZD6738

The Ataxia Telangiectasia Mutated (ATM) protein kinase is mutated in several human cancers, presenting potential opportunities for targeted cancer therapy. We previously reported that the poly-ADP-ribose polymerase (PARP) inhibitor olaparib induces transient G2 arrest but not cell death in ATM-deficient lung cancer cells, while the combination of olaparib with the ATM- and Rad3-related (ATR) inhibitor VE-821 induced cell death. Here, we show that combination of olaparib plus the clinically relevant ATR inhibitor AZD6738 also induces cell death in ATM-deficient lung, prostate and pancreatic cancer cells with little effect on their ATM-proficient counterparts. Together, our data suggest that lung, prostate and pancreatic patients whose tumours exhibit loss or inactivation of ATM may benefit from combination of a PARP inhibitor plus an ATR inhibitor.