Increased level of extracellular ATP at tumor sites: In vivo imaging with plasma membrane luciferase

Patrizia Pellegatti, Lizzia Raffaghello, Giovanna Bianchi, Federica Piccardi, Vito Pistoia, Francesco Di Virgilio

Research output: Contribution to journalArticle

Abstract

Background: There is growing awareness that tumour cells build up a "self-advantageous" microenvironment that reduces effectiveness of anti-tumour immune response. While many different immunosuppressive mechanisms are likely to come into play, recent evidence suggests that extracellular adenosine acting at A2A receptors may have a major role in down-modulating the immune response as cancerous tissues contain elevated levels of adenosine and adenosine break-down products. While there is no doubt that all cells possess plasma membrane adenosine transporters that mediate adenosine uptake and may also allow its release, it is now clear that most of extracellularly-generated adenosine originates from the catabolism of extracellular ATP. Methodology/Principal Findings: Measurement of extracellular ATP is generally performed in cell supernatants by HPLC or soluble luciferin-luciferase assay, thus it generally turns out to be laborious and inaccurate. We have engineered a chimeric plasma membrane-targeted luciferase that allows in vivo real-time imaging of extracellular ATP. With this novel probe we have measured the ATP concentration within the tumour microenvironment of several experimentally-induced tumours. Conclusions/Significance: Our results show that ATP in the tumour interstitium is in the hundrends micromolar range, while it is basically undetectable in healthy tissues. Here we show that a chimeric plasma membrane-targeted luciferase allows in vivo detection of high extracellular ATP concentration at tumour sites. On the contrary, tumour-free tissues show undetectable extracellular ATP levels. Extracellular ATP may be crucial for the tumour not only as a stimulus for growth but also as a source of an immunosuppressive agent such as adenosine. Our approach offers a new tool for the investigation of the biochemical composition of tumour milieu and for development of novel therapies based on the modulation of extracellular purine-based signalling.

Original languageEnglish
Article numbere2599
JournalPLoS One
Volume3
Issue number7
DOIs
Publication statusPublished - Jul 9 2008

Fingerprint

luciferase
Cell membranes
Luciferases
adenosine
Tumors
plasma membrane
Adenosine Triphosphate
Cell Membrane
image analysis
Adenosine
Imaging techniques
neoplasms
Neoplasms
immunosuppressive agents
Immunosuppressive Agents
Tissue
luciferin
immune response
Tumor Microenvironment
Membrane Transport Proteins

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Increased level of extracellular ATP at tumor sites : In vivo imaging with plasma membrane luciferase. / Pellegatti, Patrizia; Raffaghello, Lizzia; Bianchi, Giovanna; Piccardi, Federica; Pistoia, Vito; Di Virgilio, Francesco.

In: PLoS One, Vol. 3, No. 7, e2599, 09.07.2008.

Research output: Contribution to journalArticle

Pellegatti, Patrizia ; Raffaghello, Lizzia ; Bianchi, Giovanna ; Piccardi, Federica ; Pistoia, Vito ; Di Virgilio, Francesco. / Increased level of extracellular ATP at tumor sites : In vivo imaging with plasma membrane luciferase. In: PLoS One. 2008 ; Vol. 3, No. 7.
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