Wnt/β-catenin signaling is required for CRC cell chemoresistance. a β-catenin was silenced in HCT116 and SW480 cells. The protein levels of β-catenin as determined by Western blot analysis. b TCF4 was deleted in HCT116 and SW480 cells. The protein levels of TCF4 as determined by Western blot analysis. c MTT cell proliferation assay performed in β-catenin silencing HCT116 and SW480 cells treated with the indicated concentrations of 5-Fu. d MTT cell proliferation assay performed in TCF4 deletion HCT116 and SW480 cells treated with the indicated concentrations of 5-Fu. e MTT cell proliferation assay performed in β-catenin silencing HCT116 and SW480 cells treated with the indicated concentrations of Oxa. f MTT cell proliferation assay performed in TCF4 deletion HCT116 and SW480 cells treated with the indicated concentrations of Oxa. *P