PHA-680632 shows 30- to 200-fold higher IC50s of FLT3, LCK, PLK1, STLK2, VEGFR2, and VEGFR3 compared with Aurora A. PHA-680632 has potent antiproliferative activity in a wide range of cell types. The IC50s are 0.32, 0.41, 0.06, 1.17, 0.56, 0.62, 0.29, 0.11, 1.56, 0.62, 0.07, 0.13, 0.41 μM for C33A, HeLa, HCT116, HT29, LOVO, A549, MCF7, A2780, U2OS, DU145, U937, HL60, NHDF. PHA-680632 can cause polyploidy in tumor cells. PHA-680632 cell treatment induces phenotypes similar to Aurora A or B depletion. PHA680632, inhibits colony formation in different cancer cell lines and induced polyploidy. Aurora-A inhibition by PHA680632 enhances radiation response in cancer cells, especially in p53-deficient cells.