Definition

An orally bioavailable ATP-competitive inhibitor of ataxia telangiectasia mutated kinase (ATM), with potential chemo-/radio-sensitizing and antineoplastic activities. Upon oral administration, lartesertib targets and binds to ATM, thereby inhibiting the kinase activity of ATM and ATM-mediated signaling. This prevents DNA damage checkpoint activation, disrupts DNA damage repair, induces tumor cell apoptosis, and leads to cell death of ATM-overexpressing tumor cells. In addition, by preventing DNA damage repair, M4076 sensitizes tumor cells to chemo- and radiotherapy and increases their anti-tumor activity. ATM, a serine/threonine protein kinase upregulated in a variety of cancer cell types, is activated in response to DNA damage and plays a key role in DNA-strand repair.