The Bcl-w promoter is activated by beta-catenin/TCF4 in human colorectal carcinoma cells

Gene. 2009 Mar 1;432(1-2):112-7. doi: 10.1016/j.gene.2008.12.002. Epub 2008 Dec 16.

Abstract

The antiapoptotic BCL-2 family protein BCL-W is often overexpressed in colorectal carcinoma (CRC) where it correlates with advanced stage and expression of p53. In this work we have analysed the Bcl-w promoter to identify potential regulators of BCL-W expression in CRC cells. The Bcl-w promoter was highly active in cell lines derived from CRC as well as other cancer types. Although expression of p53 and BCL-W correlate in CRC, overexpression of wild type or mutant p53 did not significantly alter Bcl-w promoter activity, and deletion of endogenous p53 did not alter the expression of Bcl-w RNA in HCT116 cells. Promoter deletion analysis lead to the identification of a potential binding site for TCF/LEF factors, obligate binding partners for beta-catenin, a downstream target of the WNT signalling pathway. TCF4 and beta-catenin interacted with the Bcl-w promoter in intact HCT116 cells and mutation of this site significantly decreased promoter activity. The activity of the Bcl-w promoter was increased or decreased, respectively, by overexpression of beta-catenin or dominant negative TCF4. beta-catenin is activated in the majority of CRC and these results suggest that BCL-W may function as a downstream effector of inappropriate WNT/beta-catenin signalling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis Regulatory Proteins / genetics*
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Binding Sites
  • Cell Line, Tumor
  • Chromatin Immunoprecipitation
  • Cloning, Molecular
  • Colorectal Neoplasms / genetics*
  • Computational Biology
  • DNA-Binding Proteins / metabolism*
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Promoter Regions, Genetic*
  • Protein Binding
  • RNA, Neoplasm / metabolism
  • Sequence Deletion
  • Transcription Factor 4
  • Transcription Factors / metabolism*
  • Tumor Suppressor Protein p53 / metabolism
  • beta Catenin / metabolism*

Substances

  • Apoptosis Regulatory Proteins
  • BCL2L2 protein, human
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • DNA-Binding Proteins
  • RNA, Neoplasm
  • TCF4 protein, human
  • Transcription Factor 4
  • Transcription Factors
  • Tumor Suppressor Protein p53
  • beta Catenin