Discovery of novel, potent and orally available benzoazipinone derivatives that elicit MKLP2-inhibitory phenotypes

Abstract

Mitotic kinesin-like protein 2 (MKLP2/KIF20A) is a key mitotic regulator frequently overexpressed in human malignancies and its abundance is positively correlated with poor outcomes of the disease. Despite extensive research on MKLP2 as a potential target for oncology, the development of small-molecule inhibitors specific to MKLP2 remains limited. We have previously identified a benzoazipinone compound, HJ81 as a potent disruptor of Aurora kinase B (AURKB) localization during late mitosis. This study reveals that such disruption results from a failure of AURKB relocation at the onset of anaphase and this phenomenon can be specifically attributed to the disablement of MKLP2, a recognized facilitator of the relocation process. Further optimization of HJ81 leads to identifying compounds such as 12a as promising lead inhibitors of MKLP2-mediated processes, with improved pharmacokinetic properties. 12a inhibits the microtubule-stimulated ATPase activity of the recombinant MKLP2 in vitro. Significant suppression of tumor growth was observed in mice bearing the Calu-6 lung cancer cell line when treated with 12a at a well-tolerated dose. Overall, our findings suggest that benzoazipinone derivatives represent a novel chemical scaffold with the potential to be developed to mimic MKLP2 inhibition for cancer treatment.