KU-60019 is primarily utilized in research settings as a potent and selective inhibitor of ATM kinase, a key protein involved in the DNA damage response. Its application is significant in studying cellular responses to DNA damage, particularly in understanding how inhibition of ATM affects cancer cells. Researchers use KU-60019 to explore its potential in sensitizing cancer cells to radiation and chemotherapy, as blocking ATM activity can impair the repair of DNA double-strand breaks, leading to increased cell death in tumors. Additionally, it aids in investigating the role of ATM in various biological processes, including cell cycle regulation and apoptosis. Its use is largely confined to preclinical studies, offering insights into novel therapeutic strategies for cancer treatment.