title: Study of the mechanisms of cigarette smoke gas phase cytotoxicity.
abstract: BACKGROUND
  The cytotoxicity of cigarette smoke (CS) in humans is well-documented, but the mechanism behind CS toxicity and carcinogenicity remains unknown. We are interested in the toxicological effects of CS gas phase and the biological mechanisms of its action.
  
  
  METHODS
  Gas phase CS cytotoxicity was measured by Wst-1 and LDH assays, in cultured cells. The mechanism of cell death was investigated by flow cytometric analysis using Annexin V and PI staining. Gas phase CS-induced oxidative damage was evaluated by estimating cellular glutathione (GSH) levels. Protein modifications (nitration of tyrosines) induced by gas phase CS and activation of key signalling proteins (Mitogen-activated protein kinase, MAPK) were detected by immunoblotting.
  
  
  RESULTS
  The cytotoxicity of gas phase CS was found to be dose-dependent. The mechanism of cell death was found to be both apoptotic and necrotic depending on the concentrations used. Exposure to gas phase CS resulted in depletion of cellular GSH levels, increased nitrotyrosine immunoreactivity and phosphorylation of p44/42 MAPK proteins.
  
  
  CONCLUSIONS
  These results suggest that the CS gas phase alone contributes significantly to the deleterious effects of CS in cellular systems.
authors.affiliation: Institute of Biomedical Research and Biotechnology, 55 Solomou Str., Athens 10432, Greece.
authors.forename: Christina
authors.initials: C
authors.lastname: Piperi
authors.forename: Aristea E
authors.initials: AE
authors.lastname: Pouli
authors.forename: Nikolaos A
authors.initials: NA
authors.lastname: Katerelos
authors.forename: Dimitris G
authors.initials: DG
authors.lastname: Hatzinikolaou
authors.forename: Anastasia
authors.initials: A
authors.lastname: Stavridou
authors.forename: Miltiades C
authors.initials: MC
authors.lastname: Psallidopoulos
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D005740:Gases; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D009336:Necrosis; D015398:Signal Transduction / Q000187:drug effects; D012906:Smoke / Q000009:adverse effects*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D005740:Gases; D012906:Smoke; D014028:Tobacco Smoke Pollution; D007770:L-Lactate Dehydrogenase; D020929:Mitogen-Activated Protein Kinase Kinases; D005978:Glutathione