CP 466,722 is an inhibitor of ataxia-telangiectasia mutated (ATM) kinase that inhibits ionizing radiation-induced ATM autophosphorylation and phosphorylation of the ATM targets SMC1, Chk2, and p53 in HeLa cells when used at a concentration of 10 μM. It is selective for ATM over PI3K and PIKK in HFF(hTERT) and A-T(hTERT) fibroblasts, respectively. CP 466,722 decreases cell survival in response to ionizing radiation in HeLa cells. It is also cytotoxic to MCF-7 and SKBr-3 breast cancer cells (IC50s = 16.92 and 12.78 μM, respectively).
