β-Catenin/Tcf-4 signaling pathway plays important roles in colorectal tumorigenesis. RT-PCR, western blotting and immunoprecipitation were used to study the effects of curcumin on β-catenin/Tcf-4 signaling pathway in HT-29 cells. Treatment of curcumin could induce cleavage of β-catenin and the cleavage could be inhibited by caspase inhibitors. The association of β-catenin with Tcf-4 in nucleus could be inhibited by curcumin. The expression of c-myc and cyclinD1 was downregulated by curcumin, which could not be blocked by Z-DEVD-FMK. The results showed curcumin could induce the
cleavage of β-catenin by activition of caspases and downregulate the activity of β-catenin/Tcf signaling pathway independent of the caspases in HT-29 cells.