Specific Activation of A3, A2A and A1 Adenosine Receptors in CD73-Knockout Mice Affects B16F10 Melanoma Growth, Neovascularization, Angiogenesis and Macrophage Infiltration

PLoS One. 2016 Mar 10;11(3):e0151420. doi: 10.1371/journal.pone.0151420. eCollection 2016.

Abstract

CD73 (ecto-5'-nucleotidase), a cell surface enzyme hydrolyzing AMP to adenosine, was lately demonstrated to play a direct role in tumor progression including regulation of tumor vascularization. It was also shown to stimulate tumor macrophage infiltration. Interstitial adenosine, accumulating in solid tumors due to CD73 enzymatic activity, is recognized as a main mediator regulating the production of pro- and anti-angiogenic factors, but the engagement of specific adenosine receptors in tumor progression in vivo is still poorly researched. We have analyzed the role of high affinity adenosine receptors A1, A2A, and A3 in B16F10 melanoma progression using specific agonists (CCPA, CGS-21680 and IB-MECA, respectively). We limited endogenous extracellular adenosine background using CD73 knockout mice treated with CD73 chemical inhibitor, AOPCP (adenosine α,β-methylene 5'-diphosphate). Activation of any adenosine receptor significantly inhibited B16F10 melanoma growth but only at its early stage. At 14th day of growth, the decrease in tumor neovascularization and MAPK pathway activation induced by CD73 depletion was reversed by all agonists. Activation of A1AR primarily increased angiogenic activation measured by expression of VEGF-R2 on tumor blood vessels. However, mainly A3AR activation increased both the microvessel density and expression of pro-angiogenic factors. All agonists induced significant increase in macrophage tumor infiltration, with IB-MECA being most effective. This effect was accompanied by substantial changes in cytokines regulating macrophage polarization between pro-inflammatory and pro-angiogenic phenotype. Our results demonstrate an evidence that each of the analyzed receptors has a specific role in the stimulation of tumor angiogenesis and confirm significantly more multifaceted role of adenosine in its regulation than was already observed. They also reveal previously unexplored consequences to extracellular adenosine signaling depletion in recently proposed anti-CD73 cancer therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5'-Nucleotidase / deficiency*
  • 5'-Nucleotidase / genetics*
  • Adenosine / metabolism
  • Animals
  • Cell Proliferation
  • Extracellular Space / metabolism
  • Gene Expression Regulation, Neoplastic
  • Gene Knockout Techniques
  • Macrophages / cytology
  • Macrophages / immunology*
  • Male
  • Melanoma, Experimental / blood supply*
  • Melanoma, Experimental / genetics
  • Melanoma, Experimental / immunology*
  • Melanoma, Experimental / pathology
  • Mice
  • Neovascularization, Pathologic*
  • Receptor, Adenosine A1 / metabolism
  • Receptor, Adenosine A2A / metabolism
  • Receptor, Adenosine A3 / metabolism
  • Receptors, Purinergic P1 / metabolism*
  • Signal Transduction
  • Up-Regulation

Substances

  • Receptor, Adenosine A1
  • Receptor, Adenosine A2A
  • Receptor, Adenosine A3
  • Receptors, Purinergic P1
  • 5'-Nucleotidase
  • Adenosine

Grants and funding

This work was supported by grant N N401 006938 from National Science Centre (https://www.ncn.gov.pl/) (PK); grant STRATEGMED1/233226/11/NCBR/2015 strategic programmes “Prevention practices and treatment of civilization” - STRATEGMED: “Prostacyclin, nitric oxide and carbon monoxide - based pharmacotherapy of endothelial dysfunction and platelet activation - a novel strategy to inhibit cancer metastasis” (METENDOPHA) (http://www.ncbir.pl/) (PK); European Social Fund POKL.04.01.01-00-017/10-00 “We educate the best - a comprehensive program of development of graduate students, young doctors and academic teaching staff of the University of Gdańsk” (http://ec.europa.eu/esf/home.jsp) (MG). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.