Title: Zinc chromate induces chromosome instability and DNA double strand breaks in human lung cells.
Authors: Xie, Hong; Holmes, Amie L; Young, Jamie L; Qin, Qin; Joyce, Kellie; Pelsue, Stephen C; Peng, Cheng; Wise, Sandra S; Jeevarajan, Antony S; Wallace, William T; Hammond, Dianne; Wise Sr, John Pierce
Published In Toxicol Appl Pharmacol, (2009 Feb 01)
Abstract: Hexavalent chromium Cr(VI) is a respiratory toxicant and carcinogen, with solubility playing an important role in its carcinogenic potential. Zinc chromate, a water insoluble or 'particulate' Cr(VI) compound, has been shown to be carcinogenic in epidemiology studies and to induce tumors in experimental animals, but its genotoxicity is poorly understood. Our study shows that zinc chromate induced concentration-dependent increases in cytotoxicity, chromosome damage and DNA double strand breaks in human lung cells. In response to zinc chromate-induced breaks, MRE11 expression was increased and ATM and ATR were phosphorylated, indicating that the DNA double strand break repair system was initiated in the cells. In addition, our data show that zinc chromate-induced double strand breaks were only observed in the G2/M phase population, with no significant amount of double strand breaks observed in G1 and S phase cells. These data will aid in understanding the mechanisms of zinc chromate toxicity and carcinogenesis.
PubMed ID: 19027772
MeSH Terms: Ataxia Telangiectasia Mutated Proteins; Cell Cycle Proteins/metabolism; Cell Cycle/drug effects; Cell Line; Cell Survival/drug effects; Chromates/toxicity*; Chromosomal Instability*; DNA Breaks, Double-Stranded*; DNA-Binding Proteins/metabolism; DNA/drug effects*; DNA/metabolism; Dose-Response Relationship, Drug; Fibroblasts/drug effects*; Fibroblasts/metabolism; Fibroblasts/pathology; Humans; Lung/drug effects*; Lung/metabolism; Lung/pathology; MRE11 Homologue Protein; Mutagens/toxicity*; Phosphorylation; Protein-Serine-Threonine Kinases/metabolism; Tumor Suppressor Proteins/metabolism; Up-Regulation; Zinc Compounds/toxicity*