[CAS NO. 911222-45-2]  Rabusertib (LY2603618)

Chk1 is an ATP-dependent serine-threonine kinase and a key component in the DNA replication-monitoring checkpoint system activated by double-stranded breaks (DSBs). Chk1 contributes to all currently defined cell cycle checkpoints, including G1/S, intra-S-phase, G2/M, and the mitotic spindle checkpoint. By inhibiting the activity of chk1, LY2603618 prevents the repair of DNA caused by DNA-damaging agents, thus potentiating the antitumor efficacies of various chemotherapeutic agents. However, preclinical data involving LY2603618 has not been published until now. Inhibition of Chk1 is predicted to enhance the effects of antimetabolites, such as gemcitabine. LY2603618 treatment impairs DNA synthesis, increases DNA damage (via mitotic defects), induces apoptosis, and has synergistic activity with pemetrexed, especially in p53 mutant tumor cells.