Expression of beta-catenin is regulated by PI-3 kinase and sodium butyrate in colorectal cancer cells

Int J Mol Med. 2006 Jan;17(1):69-75.

Abstract

beta-catenin has a dual function; it is implicated in intercellular junctions and transcriptional co-activation. Here we examined the regulation of the expression and localization of beta-catenin in HT29 colorectal adenocarcinoma cells. Our results showed that inhibition of PI-3 kinase with wortmannin was accompanied by a considerably reduced expression of beta-catenin. This effect was overcome by butyrate and occurred at the protein level, not at the level of mRNA. Moreover, NaBT significantly increased the phosphorylation of the ribosomal protein, S6, known to participate in the translational control of gene expression. This was accompanied by the increased phosphorylation of p70 S6K and MAPKs, the effector proteins that are upstream of protein S6 in the distinct signaling pathways. These facts indicate that different signaling pathways may be involved in the regulation of beta-catenin synthesis. Modulation of beta-catenin expression induced by NaBT appeared to occur at the level of protein translation, suggesting that NaBT may act as a translational regulator.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / metabolism*
  • Alkaline Phosphatase / metabolism
  • Androstadienes / metabolism
  • Butyrates / metabolism*
  • Cell Line, Tumor
  • Colorectal Neoplasms / metabolism*
  • Humans
  • Immunohistochemistry
  • Mitogen-Activated Protein Kinases / metabolism
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphoinositide-3 Kinase Inhibitors
  • Phosphorylation
  • Ribosomal Protein S6 Kinases / metabolism
  • Ribosomal Protein S6 Kinases, 70-kDa / metabolism
  • Serine / metabolism
  • Signal Transduction / physiology
  • Tyrosine / metabolism
  • Wortmannin
  • beta Catenin / genetics
  • beta Catenin / metabolism*

Substances

  • Androstadienes
  • Butyrates
  • Phosphoinositide-3 Kinase Inhibitors
  • beta Catenin
  • Tyrosine
  • Serine
  • Ribosomal Protein S6 Kinases
  • Ribosomal Protein S6 Kinases, 70-kDa
  • Mitogen-Activated Protein Kinases
  • Alkaline Phosphatase
  • Wortmannin