Induction of micronuclei and alteration of gene expression by an organomodified clay in HepG2 cells

Chemosphere. 2016 Jul:154:240-248. doi: 10.1016/j.chemosphere.2016.03.115. Epub 2016 Apr 6.

Abstract

Clay2 is an organomodified montmorillonite developed by the Technological Institute of Packaging, Transport and Logistic (ITENE) in order to improve polymeric materials used in food packaging. There is not much known on Clay2 toxic potential, particularly at DNA level, therefore it is mandatory to assess its toxicity prior to its commercialization. In the present study the human hepatoma cell line (HepG2) was exposed to non-cytotoxic concentrations of Clay2 and the genomic stability was studied with the Cytokinesis block micronucleus cytome assay, by determining the formation of micronuclei (MN), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs). Moreover, the expression of various genes involved in the mechanisms of its action using the real-time quantitative PCR was studied. The results obtained provide the evidence that Clay2 is potentially genotoxic as it increased the frequency of micronuclei. In addition it deregulated genes involved in the metabolism, immediate-early response/signaling, DNA damage and oxidative stress showing new valuable information on the cellular response to Clay2. Nonetheless, further studies are highly needed to elucidate the molecular mechanisms of clays toxicity.

Keywords: Cytokinesis block micronucleus assay; HepG2; Modified clay; Real-time quantitative PCR.

MeSH terms

  • Aluminum Silicates / toxicity*
  • Bentonite / toxicity*
  • Carcinoma, Hepatocellular
  • Cell Line, Tumor
  • Cell Nucleus
  • Clay
  • DNA Damage
  • Food Packaging / methods*
  • Gene Expression / drug effects
  • Hep G2 Cells
  • Humans
  • Immediate-Early Proteins / genetics
  • Immediate-Early Proteins / metabolism
  • Liver Neoplasms
  • Micronuclei, Chromosome-Defective / chemically induced*
  • Micronucleus Tests / methods*
  • Mutagens / toxicity*
  • Oxidative Stress / drug effects
  • Oxidative Stress / genetics
  • Real-Time Polymerase Chain Reaction

Substances

  • Aluminum Silicates
  • Immediate-Early Proteins
  • Mutagens
  • Bentonite
  • Clay