M2912 (MSC2504877) is a very potent TNKS1/TNKS2 inhibitor (IC50=0.6 nM for TNKS1) with exquisite selectivity over other PARP family enzymes and favorable compound properties. This inhibitor potently modulates the Wnt/β-catenin pathway by elevating the levels of axin2 (EC50=17 nM) and tankyrase in DLD1 cells in a dose-dependent manner resulting in reduced cellular Wnt reporter activity.