ATM in DNA repair in cancer

Alterations in DNA damage response (DDR) pathways are hallmarks of cancer. Incorrect repair of DNA lesions often leads to genomic instability. Ataxia telangiectasia mutated (ATM), a core component of the DNA repair system, is activated to enhance the homologous recombination (HR) repair pathway upon DNA double-strand breaks. Although ATM signaling has been widely studied in different types of cancer, its research is still lacking compared with other DDR-involved molecules such as PARP and ATR. There is still a vast research opportunity for the development of ATM inhibitors as anticancer agents. Here, we focus on the recent findings of ATM signaling in DNA repair of cancer. Previous studies have identified several partners of ATM, some of which promote ATM signaling, while others have the opposite effect. ATM inhibitors, including KU-55933, KU-60019, KU-59403, CP-466722, AZ31, AZ32, AZD0156, and AZD1390, have been evaluated for their antitumor effects. It has been revealed that ATM inhibition increases a cancer cell's sensitivity to radiotherapy. Moreover, the combination with PARP or ATR inhibitors has synergistic lethality in some cancers. Of note, among these ATM inhibitors, AZD0156 and AZD1390 achieve potent and highly selective ATM kinase inhibition and have an excellent ability to penetrate the blood-brain barrier. Currently, AZD0156 and AZD1390 are under investigation in phase I clinical trials. Taken together, targeting ATM may be a promising strategy for cancer treatment. Hence, further development of ATM inhibitors is urgently needed in cancer research.