PHA-680632S1454

PHA-680632 potently inhibits all three Aurora kinases (A, B, and C) with IC50 values of 27, 135, and 120 nM, respectively. PHA-680632 is selective for Aurora kinases, with 10- to 200-fold higher IC50 for FGFR1, FLT3, LCK, PLK1, STLK2, VEGFR2, and VEGFR3, and with IC50 higher than 10 μM for another 22 kinases. PHA-680632 shows potent anti-proliferative effects in a wide range of cell types with IC50 values of 0.06–7.15 μM, including HeLa, HCT116, HT29, LOVO, DU145, and NHDF cells. PHA-680632 (0.5 μM) causes polyploidy in tumor cells. The mechanism of action of PHA-680632 is in agreement with inhibition of Aurora kinases. ^[1] PHA680632 in association with radiation leads to additive effects in cancer cells, especially in the p53-deficient cells. Combined ionising radiation (IR) and treatment of PHA680632 (100–400 nM) prior to IR leads to an enhancement of radiation-induced Annexin V positive cells, micronuclei formation, and Brca1 foci formation only in HCT116 cells with deficient p53, other than the p53 wild-type counterparts. ^[2]