An inhibitor of USP2 (IC50 = 1.1 μM); inhibits the closely related USP8 (IC50 = 0.95 μM); no activity at multiple proteases or 102 kinases, including cell cycle regulators; increases cyclin D1 degradation in HCT116 cells; induces cell cycle arrest at the G1 phase in Mino and HCT116 cells; inhibits proliferation of HCT116 cells (IC50 = 3.6 μM); decreases homologous recombination-mediated DNA repair in DR-GFP U2OS cells,