title: Genotoxic and cell-transformation effects of multi-walled carbon nanotubes (MWCNT) following in vitro sub-chronic exposures.
abstract: BEAS-2B cells were sub-chronically exposed (up to 4 weeks) to low doses of multi-walled carbon nanotubes (MWCNT, NM403). Genotoxic effects were evaluated using the comet and the micronucleus (MN) assays at three different time-points. The expression of different interleukins (IL) such as IL-1B, IL-6 and IL-8, as well as HO-1 as stress marker, was assessed after 3 weeks treatments. As a hallmark biomarker of cell-transforming ability we used the soft-agar assay, which detects anchorage-independent cell growth. Our results show high levels of intracellular reactive oxygen species (ROS) associated to MWCNT exposure. Nevertheless, an important proportion of these ROS levels seems to be associated to solubilized metals contaminants present in NM403, more than to the internalized MWCNT. No primary DNA damage was obtained in the Comet assay although significant levels of chromosome damage were detected using the micronucleus assay. A significant decrease in the expression of the studied cytokines was observed and significant increases in the number of induced colonies were obtained when the ability of induce anchorage-independent growth was determined. These results show that chromosome damage and reducing inflammatory signalling correlated with an increase in attachment-independent growth associated with sub-chronic MWCNT exposure.
authors.affiliation: Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.
authors.forename: Gerard
authors.initials: G
authors.lastname: Vales
authors.affiliation: Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Rubio
authors.affiliation: Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, Spain; CIBER Epidemiología y Salud Pública, Instituto de Salud Carlos III, Madrid, Spain. Electronic address: ricard.marcos@uab.es.
authors.forename: Ricard
authors.initials: R
authors.lastname: Marcos
mesh_terms: D002460:Cell Line; D020552:Comet Assay; D051547:Heme Oxygenase-1 / Q000235:genetics; D006801:Humans; D053583:Interleukin-1beta / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D016209:Interleukin-8 / Q000235:genetics; D008670:Metals / Q000032:analysis / Q000633:toxicity; D015162:Micronucleus Tests; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: C508600:IL6 protein, human; D053583:Interleukin-1beta; D015850:Interleukin-6; D016209:Interleukin-8; D008670:Metals; D037742:Nanotubes, Carbon; D017382:Reactive Oxygen Species; C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1
keywords: BEAS-2B cells; Cell-transformation; Genotoxicity; Multi-walled carbon nanotubes; Sub-chronic exposures