Nanoparticle-driven DNA damage mimics irradiation-related carcinogenesis pathways

R. M. Mroz, R. P. F. Schins, H. Li, L. A. Jimenez, E. M. Drost, A. Holownia, W. MacNee, K. Donaldson

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The epidemiological association between cancer and exposure to ambient air pollution particles (particles with a 50% cut-off aerodynamic diameter of 10 jam (PM10)) has been related to the ability of PM10 and its constituent nanoparticles (NPs) to cause reactive oxidative species (ROS)-driven DNA damage. However, there are no data on the molecular response to these genotoxic effects.

In order to assess whether PM10, NP and ROS-driven DNA damage induce carcinogenesis pathways, A549 cells were treated with tert-butyl-hyperperoxide (Tbh), urban dust (UD), carbon black (CB), nanoparticulate CB (NPCB), benzo(a)pyrene (BaP) and NPCB coated with BaP for <= 24 h. Single- and double-strand breakage of DNA was determined by comet assay; cell cycle status was analysed using flow cytometry. Nuclear extracts or acid-extracted histories were used for Western blot analysis of p-ser15-p53 (p53 phosphorylated at ser15), p53 binding protein (53BP) 1, phospho-histone H2A.X (p-H2A.X) and phospho-BRCA1 (p-BRCA1).

UD caused both single- and double-strand DNA breaks, while other tested NPs caused only single-strand DNA breaks. NPs significantly altered cell cycle kinetics. Tbh enhanced p-H2A.X after 1 and 6 h (2.1- and 2.2-fold, respectively). NP increased 53BP1 expression at 1 h (2.4-8.7-fold) and p-BRCA1 at 1-6 h. N-acetylcysteine blocked NP-driven p-ser15-p53 response.

In conclusion, nanoparticles and reactive oxidative species induce DNA damage, activating p53 and proteins related to DNA repair, mimicking irradiation-related carcinogenesis pathways.

Original languageEnglish
Pages (from-to)241-251
Number of pages11
JournalEuropean Respiratory Journal
Issue number2
Publication statusPublished - Feb 2008

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