!Name=Induction of dnTCF-4 in Ls174T CRC cells !ExptSetNo=1723 !Description=The transactivation of TCF target genes induced by Wnt pathway mutations constitutes the primary transforming event in colorectal cancer (CRC). We show that disruption of beta-catenin/TCF-4 activity in CRC cells induces a rapid G1 arrest and blocks a genetic program that is physiologically active in the proliferative compartment of colon crypts. Coincidently, an intestinal differentiation program is induced. The TCF-4 target gene c-MYC plays a central role in this switch by direct repression of the p21(CIP1/WAF1) promoter. Following disruption of beta-catenin/TCF-4 activity, the decreased expression of c-MYC releases p21(CIP1/WAF1) transcription, which in turn mediates G1 arrest and differentiation. Thus, the beta-catenin/TCF-4 complex constitutes the master switch that controls proliferation versus differentiation in healthy and malignant intestinal epithelial cells. !Name=Tcf4-DN 11hr !Exptid=6432 !Name=TcF4-DN 11hr (duplo) !Exptid=10350 !Name=Tcf4-DN 23hr !Exptid=6443 !Name=TcF4-DN 23hr (duplo) !Exptid=10351