Cyto-genotoxic and DNA methylation changes induced by different crystal phases of TiO2-np in bronchial epithelial (16-HBE) cells

Publication date: Available online 10 February 2017 Source:Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis Author(s): Manosij Ghosh, Deniz Oner, Radu-Corneliu Duca, Stevan Cokic, Sven Seys, Stef Kerkhofs, Kirsten Van Landuyt, Peter Hoet, Lode Godderis With the increase in use of TiO2-np, a better understanding of their safety is important. In the present study the effect of different crystal phases of TiO2-np (anatase, rutile and anatase: rutile mixture; 20–26nm) were studied for cyto-genotoxicity and global DNA methylation and hydroxymethylation. Cytotoxic response was observed at a concentration of 25μg/ml for the particles tested. Results of comet and micronucleus (with and without CytB) assays revealed significant genotoxic effect of these particles. Flow cytometry revealed cell cycle arrest in the S-phase. Based on the results, toxicity of the particles could be correlated with their physico-chemical properties (i.e. smaller size and hydrodynamic diameter and larger surface area), anatase form being the most toxic. From the results of the cyto-genotoxicity assays, concentrations were determined for the epigenetic study. Effect on global DNA methylation and hydroxymethylation levels were studied at cyto-genotoxic (25μg/ml), genotoxic (12.5μg/ml) and sub cyto-genotoxic (3.25μg/ml) concentrations using LC-MS/MS analysis. Though no significant changes were observed for 3h treatment schedule; significant hypomethylation were observed at ...
Source: Mutation Research Fundamental and Molecular Mechanisms of Mutagenesis - Category: Cytology Source Type: research