Different mechanisms are involved in oxidative DNA damage and genotoxicity induction by ZnO and TiO2 nanoparticles in human colon carcinoma cells

In this work we investigated the genotoxicity of zinc oxide and titanium dioxide nanoparticles (ZnO NPs; TiO2 NPs) induced by oxidative stress on human colon carcinoma cells (Caco-2 cells). We measured free radical production in acellular conditions by Electron Paramagnetic Resonance technique and genotoxicity by micronucleus and Comet assays. Oxidative DNA damage was assessed by modified Comet assay and by measuring 8-oxodG steady state levels. The repair kinetics of DNA oxidation as well as the expression levels of hOGG1 were also analyzed. Even if both NPs were able to produce ROS in acellular conditions and to increase 8-oxodG levels in Caco-2 cells, only ZnO NPs resulted genotoxic inducing micronuclei and DNA damage. Furthermore, Caco-2 cells exposed to ZnO NPs were not able to repair the oxidative DNA damage that was efficiently repaired after TiO2 NPs treatment, through OGG1 involvement. These results indicate that the high oxidant environment caused by ZnO NPs in our cellular model can induce DNA damage and affect the repair pathways.

ZIJNO Andrea;  DE ANGELIS Isabella;  DE BERARDIS Barbara;  ANDREOLI Cristina;  RUSSO Maria Teresa;  PIETRAFORTE Donatella;  SCORZA Giuseppe;  DEGAN Paolo;  PONTI Jessica;  ROSSI Francois;  BARONE Flavia; 

2015-08-05

PERGAMON-ELSEVIER SCIENCE LTD

JRC88474

0887-2333,   

http://www.sciencedirect.com/science/article/pii/S0887233315001459,    https://publications.jrc.ec.europa.eu/repository/handle/JRC88474,   

10.1016/j.tiv.2015.06.009,