Activator protein 2alpha suppresses intestinal tumorigenesis in the Apc(min) mouse.

TitleActivator protein 2alpha suppresses intestinal tumorigenesis in the Apc(min) mouse.
Publication TypeJournal Article
Year of Publication2009
AuthorsLi Q, Löhr CV, Dashwood RH
JournalCancer letters
Volume283
Issue1
Pagination36-42
Date Published2009 Sep 28
ISSN1872-7980
KeywordsAdenomatous Polyposis Coli Protein, Animals, beta Catenin, Blotting, Western, Cell Transformation, Neoplastic, Colorectal Neoplasms, Gene Therapy, Humans, Immunohistochemistry, Immunoprecipitation, Intestinal Polyps, Mice, Mice, Knockout, Signal Transduction, Transcription Factor AP-2, Wnt Proteins
Abstract

Activator protein 2alpha (AP-2alpha) is a putative tumor suppressor, and various reports have described the loss or reduction of AP-2alpha expression in cutaneous malignant melanomas, as well as in cancers of the prostate, breast and colon. Previously, AP-2alpha was shown to attenuate beta-catenin/T-cell factor-4 (TCF-4) nuclear interactions and beta-catenin/TCF-4-dependent transcriptional activity in human colorectal cancer cells [Q. Li, R.H. Dashwood, Activator protein 2alpha associates with adenomatous polyposis coli/beta-catenin and Inhibits beta-catenin/T-cell factor transcriptional activity in colorectal cancer cells, J. Biol. Chem. 279 (2004) 45669-45675]. Here, we show that in vivo gene delivery of AP-2alpha suppressed intestinal polyp formation in the Apc(min) mouse, and protected against the development of anemia and splenomegaly. Immunoblot analyses and immunohistochemistry following gene delivery revealed an increase in AP-2alpha expression in the mouse intestinal mucosa and liver. Co-immunoprecipitation experiments provided evidence for interactions between AP-2alpha, beta-catenin, and adenomatous polyposis coli (APC) proteins in mouse intestinal mucosa, as well as in a primary human colorectal cancer. Collectively, these studies support a tumor suppressor role for AP-2alpha in the gastrointestinal tract, and suggest that AP-2alpha represents a novel target for therapeutic intervention in human cancers characterized by dysregulated Wnt signaling.

Alternate JournalCancer Lett.