FIG. 5.
Effects of Idax on β-catenin signaling. (A) Inhibition of Wnt-3a-induced accumulation of β-catenin by Idax. After L cells stably expressing Neo (control L cells [L/C]) (upper panel) and L-Idax cells (middle panel) were treated with the indicated amounts of Wnt-3a conditioned medium for 40 min, the cells were lysed and probed with the anti-β-catenin antibody. The results shown in the upper and middle panels are representative of three independent experiments. The amounts of β-catenin were analyzed using the NIH Image system and expressed as fold increase compared with the level observed in L/C cells treated with control medium. The results shown are the mean ± the standard error (SE) of three independent experiments (lower panel). ○, L/C cells; ●, L-Idax cells. (B) Inhibition of Wnt-3a-induced Tcf activation by Idax. L/C cells (lanes 1 to 4) and L-Idax cells (lanes 5 to 8) transfected with pTOPFLASH (black bars) or pFOPFLASH (white bars) were treated with Wnt-3a-conditioned medium (lanes 3, 4, 7, and 8) or control medium (lanes 1, 2, 5, and 6) for 6 h. Luciferase activity was assayed and expressed as fold increase compared with the level observed in cells transfected with pTOPFLASH and treated with control medium. These results represent the mean ± SE of five independent experiments. (C) Inhibition of Dvl- and β-catenin-dependent Tcf activation by Idax. pCGN-Dvl-1 and pEF-BOS-HA/Idax (lanes 3 to 12) or pUC/EF-1α/β-cateninSA and pEF-BOS-HA/Idax (lanes 13 to 16) were transfected into 293 cells with pTOPFLASH (black bars) or pFOPFLASH (white bars). After 46 h, luciferase activity was assayed and expressed as fold increase compared with the level observed in cells transfected with pTOPFLASH. These results represent the mean ± SE of four independent experiments.