Tankyrase (TNKS) inhibitor (IC50 values are 0.011 and 0.004 μM for TNKS1 and TNKS2 respectively). Antagonizes wnt signaling via stimulation of β-catenin degradation and stabilization of axin. Inhibits proliferation of the μ-catenin-dependent colon carcinoma cell line DLD-1.