AZ3146 is a reasonably potent and selective Mps1 inhibitor with IC₅₀ of 35 nM for Mps1^Cat. IC50 & Target: IC50: 35 nM (Mps1)^[1] In Vitro: In in vitro kinase assays, AZ3146 inhibits human Mps1^Cat with IC₅₀ of ~35 nM. AZ3146 also efficiently inhibits autophosphorylation of full-length Mps1 immunoprecipitated from human cells^[1]. TTK specific kinase inhibitor AZ3146 can decrease HCC cell growth. In vitro cell cytotoxicity assays are performed on SMMC-7721 and BEL-7404 cells. IC₅₀s are calculated as being 7.13 μM (BEL-7404) and 28.62 μM (SMMC-7721). Both cells are further treated under the concentration of IC50 for 4 days. Significant inhibitions of cell proliferation are observed^[2]. HCT116 cells are cultured for 10 days in 0.8 μM (the GI₅₀) of AZ3146 , then 2 μM AZ3146 for 3 weeks. Sixteen clones are isolated and cell lines generated, named AzR1-16, all of which are resistant to AZ3146-induced cell death in cell viability assays; AzR3 and 4 have a GI₅₀ of approximately 3 μM (4-fold resistance), while the remaining clones have a GI₅₀ of approximately 9 μM (11-fold resistance). When analyzing mitosis by time-lapse microscopy, while 2 μM AZ3146 causes the parental cell line to rapidly exited mitosis in 10 minutes^[3].