Role of a BCL9-related beta-catenin-binding protein, B9L, in tumorigenesis induced by aberrant activation of Wnt signaling

Cancer Res. 2004 Dec 1;64(23):8496-501. doi: 10.1158/0008-5472.CAN-04-2254.

Abstract

Wnt signaling plays a crucial role in a number of developmental processes and in tumorigenesis. beta-Catenin is stabilized by Wnt signaling and associates with the TCF/LEF family of transcription factors, thereby activating transcription of Wnt target genes. Constitutive activation of beta-catenin-TCF-mediated transcription resulting from mutations in adenomatous polyposis coli (APC), beta-catenin, or Axin is believed to be a critical step in tumorigenesis among divergent types of cancers. Here we show that the transactivation potential of the beta-catenin-TCF complex is enhanced by its interaction with a BCL9-like protein, B9L, in addition to BCL9. We found that B9L is required for enhanced beta-catenin-TCF-mediated transcription in colorectal tumor cells and for beta-catenin-induced transformation of RK3E cells. Furthermore, expression of B9L was aberrantly elevated in about 43% of colorectal tumors, relative to the corresponding noncancerous tissues. These results suggest that B9L plays an important role in tumorigenesis induced by aberrant activation of Wnt signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Transformation, Neoplastic
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / metabolism
  • Cytoskeletal Proteins / metabolism*
  • Cytoskeletal Proteins / physiology
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / physiology*
  • Humans
  • Immunohistochemistry
  • Intercellular Signaling Peptides and Proteins / physiology*
  • Lymphoid Enhancer-Binding Factor 1
  • Molecular Sequence Data
  • Neoplasm Proteins
  • Protein Binding
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / physiology
  • Trans-Activators / metabolism*
  • Trans-Activators / physiology
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcription Factors / physiology*
  • Transcription, Genetic
  • Transfection
  • Wnt Proteins
  • beta Catenin

Substances

  • BCL9L protein, human
  • Bcl9l protein, rat
  • CTNNB1 protein, human
  • Ctnnb1 protein, rat
  • Cytoskeletal Proteins
  • DNA-Binding Proteins
  • Intercellular Signaling Peptides and Proteins
  • Lymphoid Enhancer-Binding Factor 1
  • Neoplasm Proteins
  • Trans-Activators
  • Transcription Factors
  • Wnt Proteins
  • beta Catenin