ATM Inhibitor-7 is a potent and selective ataxia-telangiectasia mutated ( ATM ) inhibitor with an IC 50 value of 1.0 nM. ATM Inhibitor-7 induces Apoptosis and cell cycle arrest at G2/M phase when combinanted with CPT-11. ATM Inhibitor-7 combines with CPT-11 shows antitumor activity.