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Cancer Res. 2009 May 15;69(10):4125-33. doi: 10.1158/0008-5472.CAN-08-4402. Epub 2009 May 12.

Haploinsufficiency of Krüppel-like factor 5 rescues the tumor-initiating effect of the Apc(Min) mutation in the intestine.

Author information

1
Division of Digestive Diseases, Department of Medicine, Department of Pharmacology, and Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA.

Abstract

Inactivation of the tumor suppressor adenomatous polyposis coli, with the resultant activation of beta-catenin, is the initiating event in the development of a majority of colorectal cancers. Krüppel-like factor 5 (KLF5), a proproliferative transcription factor, is highly expressed in the proliferating intestinal crypt epithelial cells. To determine whether KLF5 contributes to intestinal adenoma formation, we examined tumor burdens in Apc(Min/+) mice and Apc(Min/+)/Klf5(+/-) mice. Compared with Apc(Min/+) mice, Apc(Min/+)/Klf5(+/-) mice had a 96% reduction in the number of intestinal adenomas. Reduced tumorigenicity in the Apc(Min/+)/Klf5(+/-) mice correlated with reduced levels and nuclear localization of beta-catenin as well as reduced expression of two beta-catenin targets, cyclin D1 and c-Myc. In vitro studies revealed a physical interaction between KLF5 and beta-catenin that enhanced the nuclear localization and transcriptional activity of beta-catenin. Thus, KLF5 is necessary for the tumor-initiating activity of beta-catenin during intestinal adenoma formation in Apc(Min/+) mice, and reduced expression of KLF5 offsets the tumor-initiating activity of the Apc(Min) mutation by reducing the nuclear localization and activity of beta-catenin.

PMID:
19435907
PMCID:
PMC2702486
DOI:
10.1158/0008-5472.CAN-08-4402
[Indexed for MEDLINE]
Free PMC Article

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