ETC-159 treatment causes decreased abundance of Wnt3a-stabilized β-catenin protein in both mouse L cells and HEK293 cells. ETC-159 inhibits β-catenin signaling in response to multiple active Wnts. ETC-159 inhibits mouse PORCN with an IC50 of 18.1 nM, whereas the IC50 for Xenopus Porcn is approximately fourfold higher (70 nM).