title: A₃ receptors are overexpressed in pleura from patients with mesothelioma and reduce cell growth via Akt/nuclear factor-κB pathway.
abstract: BACKGROUND
  A strong link has been established between exposure to asbestos and increased risk for pleural malignant mesothelioma (MM). Adenosine plays a key role in inflammatory processes and cancer, where it is involved in the regulation of cell death and proliferation.
  
  
  OBJECTIVE
  The primary aim of this study was to investigate the presence of adenosine receptors (ARs) in human MM pleura (MMP) and healthy mesothelial pleura (HMP). To shed some light on the interaction between adenosine and MM, the presence and functionality of ARs were explored in human healthy mesothelial cells (HMC) and in malignant mesothelioma cells (MMC).
  
  
  METHODS
  ARs were analyzed by using reverse transcriptase-polymerase chain reaction, Western blotting, and saturation binding assays. HMC were treated with crocidolite asbestos, which is the principal risk factor for MM. The role of A₃ ARs on these cellular models, evaluating cAMP production, Akt phosphorylation, and nuclear factor (NF)-κB activation, was investigated. The dual effect of A₃AR stimulation on healthy and cancer cell growth was studied by means of proliferation, apoptosis, and cytotoxicity assays.
  
  
  RESULTS
  A₃AR was up-regulated by 2.5-fold (P < 0.01) in MMP when compared with HMP. Stimulation of A₃ARs decreased proliferation and exerted a cytotoxic and proapoptotic effect on MMC and on HMC exposed to asbestos and tumor necrosis factor-α, but not on HMC with an involvement of the deregulation of Akt/NF-κB cell survival pathway.
  
  
  CONCLUSIONS
  These new findings suggest that A₃AR could represent a pharmacological target to prevent tumor development after asbestos exposure and to treat full-blown MM.
authors.affiliation: Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Ferrara, Italy.
authors.forename: Katia
authors.initials: K
authors.lastname: Varani
authors.forename: Stefania
authors.initials: S
authors.lastname: Maniero
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Vincenzi
authors.forename: Martina
authors.initials: M
authors.lastname: Targa
authors.forename: Angela
authors.initials: A
authors.lastname: Stefanelli
authors.forename: Pio
authors.initials: P
authors.lastname: Maniscalco
authors.forename: Fernanda
authors.initials: F
authors.lastname: Martini
authors.forename: Mauro
authors.initials: M
authors.lastname: Tognon
authors.forename: Pier Andrea
authors.initials: PA
authors.lastname: Borea
mesh_terms: D000328:Adult; D017209:Apoptosis; D017638:Asbestos, Crocidolite; D015153:Blotting, Western; D049109:Cell Proliferation; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D008297:Male; D008654:Mesothelioma / Q000378:metabolism* / Q000473:pathology*; D008875:Middle Aged; D016328:NF-kappa B / Q000378:metabolism*; D010994:Pleura / Q000378:metabolism / Q000473:pathology; D010997:Pleural Neoplasms / Q000378:metabolism* / Q000473:pathology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D043684:Receptor, Adenosine A3 / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: D016328:NF-kappa B; D043684:Receptor, Adenosine A3; D017638:Asbestos, Crocidolite; D051057:Proto-Oncogene Proteins c-akt