Id2 Is a Target of the β-Catenin/T Cell Factor Pathway in Colon Carcinoma

Abstract

Activation of β-catenin/T cell factor (TCF) transcription as a result of mutations in the adenomatous polyposis coli (APC) and/or β-catenin genes occurs in the majority of colon tumors. An increasing number of genes, including c-myc and cyclin D1, have been implicated as targets of this pathway. We now report that the dominant negative helix-loop-helix regulator Id2 is also a target of the β-catenin/TCF transcription pathway in colon adenocarcinoma. Investigation of the mechanism for the overexpression of Id2 in colon carcinoma cells demonstrated that the Id2 promoter is activated, and the Id2 protein is up-regulated by β-catenin. Conversely, reducing free β-catenin blocked this induction of..