Computational identification and experimental characterization of an aurora kinase inhibitor.

The serine/threonine kinases of the aurora family are critical for completing various stages of mitotic cell division. They are frequently overexpressed in various cancers, associated with poor prognosis, and have been validated as an attractive drug target. Despite promising preclinical results, the clinical development of small molecule inhibitors targeting aurora kinases is often hampered by limited efficacy as single agents and severe side effects. Recent discoveries of the synthetic interaction of aurora A with various tumor suppressors and its involvement in the development of resistance to third-generation EGFR inhibitors have renewed interest in finding aurora kinase inhibitors. This study utilized computational approaches to discover an aurora kinase inhibitor. Chemical features of two structurally distinct inhibitors of aurora kinase were exploited to develop a molecular shape and color-based model for the virtual screening of small synthetic molecules in the Enamine database. Six hit compounds validated through docking and Molecular Dynamics (MD) simulation studies were evaluated in a cell-based assay. Only MC-688 inhibited both aurora kinases (A and B) and bound to both kinases in a competition binding assay. Analysis of STD-NMR and 2D NOESY spectra confirmed the computationally predicted binding mode of MC-688 with the ATP binding pocket of aurora A. MC-688 inhibited cell proliferation and long-term treatment of HCT116 colorectal cancer cells with MC-688 induced abrogated mitosis, ultimately leading to apoptotic cell death. In conclusion, MC-688 was computationally identified and experimentally validated as a new pan-aurora inhibitor that induces aurora phenotype in cells and can be used as a lead for further optimization.