Three Aurora kinases, A-C, are involved in phosphorylation events that are critical for the completion of mitosis. Aurora A, involved in centrosomal assembly and acentrosomal spindle assembly, is overexpressed in many tumors. Phthalazinone pyrazole is a potent inhibitor of Aurora A kinase (IC50 = 31 nM). It does not inhibit Aurora B kinase at doses up to 100 μM. Phthalazinone pyrazole inhibits the proliferation of HCT116, Colo205, and MCF-7 cells (IC50 = 7.8, 2.9, and 1.6 μM, respectively).
