(Z)-Mirin functions as an inhibitor targeting the MRN complex, comprising Mre11, Rad50, and Nbs1, thereby obstructing the MRN-mediated initiation of ATM activation without influencing the kinase activity of ATM itself. It effectively suppresses the exonuclease activity associated with Mre11. The compound enhances apoptosis, induces a G2/M cell cycle arrest, and significantly diminishes the efficiency of homology-directed repair (HDR)^[1].^[2].