A TNKS1/2 inhibitor (IC50s = 46 and 25 nM, respectively); selective for TNKS1 and TNKS2 over a panel of 90 kinases, 16 phosphatases, and 73 GPCRs; inhibits colony formation of COLO 320 DM and SW403 cells (200 μM); inhibits colony formation of HCC cells in a dose-dependent manner; increases differentiation marker expression in COLO 320 DM and HCT15 cells (100 nM); inhibits Wnt signaling in HEK293 and 10T1/2 cells in a dose-dependent manner; inhibits tumor growth in COLO 320 DM and SW403 mouse xenograft models (20 mg/kg, i.p., twice daily) but leads to moribundity and death at a dose of 30 mg/kg twice daily