The Wnt/β-catenin signaling pathway targets PPARγ activity in colon cancer cells

Abstract

Control of colon cell fate in adenocarcinomas is disrupted, in part, due to aberrant Wnt/β-catenin signaling. The nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ) has been implicated in the development of colon cancers. In the adenomatous polyposis coli multiple intestinal neoplasia (APC Min) mouse cancer model, PPARγ expression in the colonic mucosa is markedly altered. In addition, PPARγ protein levels are elevated, possibly through sequestration by activated β-catenin in colon cancer cell lines. Induction of the Wnt/β-catenin pathway by LiCl also elevated PPARγ levels and induced PPARγ-dependent reporter and endog-enous target genes. Mechanistically, PPARγ, through interactions with β-catenin and T cell transcription factor (Tcf)-4, may be a determinant of cell fate and is likely a target of the Wnt pathway in cancer cells.