Evaluation of P2X7 Receptor Function in Tumor Contexts Using rAAV Vector and Nanobodies (AAVnano).

Mélanie Demeules,Romain Hardet,Catalina Abad,Carolina Pinto-Espinoza,Friedrich Koch-Nolte,Henri Gondé,Friedrich Haag,Allan Scarpitta,Waldemar Schäfer,Sahil Adriouch,Anna Marei Eichhoff

doi:10.3389/fonc.2020.01699

Abstract

Adenosine triphosphate (ATP) represents a danger signal that accumulates in injured tissues, in inflammatory sites, and in the tumor microenvironment. Extracellular ATP is known to signal through plasma membrane receptors of the P2Y and P2X families. Among the P2X receptors, P2X7 has attracted increasing interest in the field of inflammation as well as in cancer. P2X7 is expressed by immune cells and by most malignant tumor cells where it plays a crucial yet complex role that remains to be clarified. P2X7 activity has been associated with production and release of pro-inflammatory cytokines, modulation of the activity and survival of immune cells, and the stimulation of proliferation and migratory properties of tumor cells. Hence, P2X7 plays an intricate role in the tumor microenvironment combining beneficial and detrimental effects that need to be further investigated. For this, we developed a novel methodology termed AAVnano based on the use of Adeno-associated viral vectors (AAV) encoding nanobodies targeting P2X7. We discuss here the advantages of this tool to study the different functions of P2X7 in cancer and other pathophysiological contexts.

Highlights

Adenosine triphosphate (ATP) released into the extracellular space represents a well-known danger signal that can signal through two main families of plasma membrane receptors: G protein-coupled receptors, named P2Y receptors, and ATP-gated ion channels termed P2X receptors [1]
Novel knockout models and P2X7-floxed mutants derived from the European Mutant Mouse Archive (EMMA) are available and may facilitate the reevaluation of P2X7 functions in vivo in different disease models [37, 38]
We found that EG7 naturally expresses P2X7 at a level that is similar to the level detected at the surface of A20-P2X7 cells obtained after stable transfection of the BALB/c mouse B cell lymphoma A20 with an expression plasmid encoding full-length mouse P2X7 [50]

Summary

Introduction

Adenosine triphosphate (ATP) released into the extracellular space represents a well-known danger signal that can signal through two main families of plasma membrane receptors: G protein-coupled receptors, named P2Y receptors, and ATP-gated ion channels termed P2X receptors [1]. Among the latter family, P2X7 ( known as P2RX7) forms a homotrimeric receptor that has attracted much interest in the fields of inflammation and cancer. Activation of P2X7 by relatively high concentrations of extracellular ATP leads to Na+ and Ca2+ influx, and K+ efflux This triggers major changes in the cellular ionic content, and signaling and metabolic pathways involved in cell activation, survival and fate. Whether this membrane permeabilization is due to dilation of the P2X7 channel itself, or the activation of non-selective pores like pannexin-1, gasdermin-D, or anoctamin-6, may depend on the cellular

Objectives

Methods

Conclusion