In experiments to examine the effects of signal inhibitors, a β-catenin signal inhibitor XAV939, which was dissolved in DMSO (dimethyl sulfoxide; D2650; Sigma-Aldrich, St. Louis, MO, USA) at 10 mM, and a MEK1/2-specific inhibitor U0126 (V1121, Promega, Fitchburg, WI, USA), which ...