Selective inhibitor of PLK1 (IC50 values are 200 pM, 875 nM and 66 μM for PLK1, PLK3 and PLK2 respectively). Targets the inactive conformation of PLK1. Displays no effect on Aurora kinase A activity. Binds and stabilizes the inactive form of PLK1. Delays cell cycle progression, reduces cell proliferation and induces apoptosis in a range of human cancer cell lines.