Discovery of pyrazolo[3,4-b]pyridine derivatives as novel and potent Mps1 inhibitors for the treatment of cancer.

Monopolar spindle kinase 1 (Mps1) is a key element of the mitotic checkpoint and clinically evaluated as a target in the treatment of aggressive tumors. With this aim, a set of pyrazolo[3,4-b]pyridine-based compounds as new Mps1 inhibitors was investigated through a multidisciplinary approach, based on virtual screening, chemical synthesis and biological evaluation. One of the representative compounds, 31, exhibited strong kinase inhibitory potency against Mps1 with an IC50 value of 2.596 nM and significantly inhibited proliferation of cancer cells, especially MDA-MB-468 and MV4-11 cells. Compound 31 also displayed reasonable kinome selectivity against a panel of 606 wild-type kinases at 1 µM. Moreover, compound 31 exhibited suitable preclinical pharmacokinetic parameters and a promising pharmacodynamic profile. Further, compound 31 showed good antitumor efficacy in MDA-MB-468 xenograft model with no obvious toxicity. Overall, compound 31 was identified as a potential Mps1 inhibitor for cancer therapy and deserve further research.