XAV-939 (NVP-XAV939) is a Tankyrase (TNKS) inhibitor that inhibits TNKS1 and TNKS2 (IC50=11/4 nM). XAV-939 selectively inhibits Wnt/β-catenin-mediated transcription.

TNKS1:11 nM (cell free), ARTD1:5500 nM, TNKS2:4 nM (cell free), ARTD2:479 nM

XAV939, the recently identified small molecule shown to specifically inhibit PARP activity of tankyrase 1 (and tankyrase 2 at higher concentrations), was used here at much lower concentrations than 3-AB. The tankyrase specific inhibitor XAV939 was solubilized in DMSO at 55°C to a stock concentration of 10mM, which was diluted to a working concentration of 100μM; final concentrations of 0.5μM or 1μM were well within the concentration parameters suggested for cell culture experiments to inhibit tankyrase specifically. Cultures were maintained under these conditions for the duration of the designated time course. Controls were exposed to DMSO alone. Following treatment, cells were lysed and prepared for western blot analysis. Tankyrase 1 and DNA-PKcs protein levels were normalized to the β-actin loading controls and quantified [1].

XAV-939, a selective inhibitor of tankyrase (TNKS)-1 and TNKS-2, was injected i.p., at a dose of 1 mg/ml, once a day for seven consecutive days of IMQ treatment (injection volume 100 μl). Control mice were injected with 100 μl 10% DMSO/90% 0.9% NaCl, the solvent for XAV-939 [3].