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Wnt and beta-catenin signaling target the expression of ecto-5'-nucleotidase and increase extracellular adenosine

Jozef Spychala1, Jan Kitajewski

  • 1Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7295, USA. jozek@med.unc.edu

Experimental Cell Research
|May 20, 2004
PubMed

Insights

Wnt/beta-catenin signaling influences extracellular adenosine generation by regulating key enzymes. This pathway impacts ecto-5'-nucleotidase and adenosine deaminase, affecting tumor microenvironments.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Oncology

Background:

  • Solid tumors generate extracellular adenosine through nucleotide degradation.
  • Adenosine levels are regulated by enzymes like ecto-5 -nucleotidase (eN) and adenosine deaminase (ADA).
  • Wnt/beta-catenin signaling is frequently deregulated in human cancers.

Purpose of the Study:

  • To investigate if Wnt/beta-catenin signaling targets eN and ADA gene expression.
  • To determine the role of Wnt signaling in extracellular adenosine generation.

Main Methods:

  • Promoter activity assays using eN promoter constructs.
  • Transfection of cells (Cos-7, Rat-1) with Wnt pathway components and antagonists.
  • Analysis of mRNA and protein expression of eN and ADA.
  • Measurement of extracellular adenosine levels.

Main Results:

  • Beta-catenin significantly increased eN promoter activity, dependent on TCF-1.
  • APC, a beta-catenin antagonist, decreased eN promoter activity.
  • Wnt-1 oncogene expression in Rat-1 cells increased eN and decreased ADA expression and activity.
  • This resulted in a threefold increase in extracellular adenosine generation.

Conclusions:

  • Wnt/beta-catenin signaling directly regulates the expression of eN and ADA.
  • This regulation links Wnt signaling to extracellular adenosine metabolism in tumors.
  • Targeting this pathway could modulate adenosine levels in cancer therapy.

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