Chromium is the proximate clastogenic species for lead chromate-induced clastogenicity in human bronchial cells

• Published in: Mutation research. Genetic toxicology and environmental mutagenesis 2004-05, Vol.560 (1), p.79-89
• Main Authors: Wise, Sandra S., Holmes, Amie L., Ketterer, Michael E., Hartsock, Wendy J., Fomchenko, Elena, Katsifis, Spiros, Thompson, W.Douglas, Wise, John Pierce
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Chromium; Chromosomal aberrations; Clastogenicity; Cytotoxicity; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; Genotoxicity; Lead chromate; Lung cancer; Medical sciences; Sodium chromate; Toxicology; WTHBF-6 cells
• ISSN: 1383-5718; 1879-3592
• DOI: 10.1016/j.mrgentox.2004.02.009

Hexavalent chromium (Cr(VI)) is a well-established human lung carcinogen with potentially widespread exposure. Solubility is a key factor in the carcinogenicity of Cr(VI), with the water-insoluble or ‘particulate’ compounds being the more potent carcinogens. Studies have indicated that the component ions are responsible for their clastogenicity, but it is uncertain whether chromium (Cr), lead (Pb) or some combination of the two is responsible for the clastogenic effects. Accordingly, we compared the clastogenicity of lead chromate (LC) with soluble sodium chromate (SC) and lead glutamate (LG) in WTHBF-6 human lung cells. We found that 1436 μM was the maximal intracellular level of Pb after exposure to clastogenic concentrations of LC. However, clastogenesis was not observed after exposure to LG, even when intracellular Pb concentrations reached 13,347 μM, indicating that intracellular Pb levels did not reach clastogenic levels in WTHBF-6 cells after LC treatment. By contrast, SC was clastogenic damaging 16 and 44% of metaphase cells at intracellular Cr doses of 312 and 1262 μM respectively, which was comparable to the clastogenesis observed after LC treatment. LC damaged 10, 27 and 37% of metaphases at intracellular Cr doses of 288, 926 and 1644 μM, respectively. These data indicate that with respect to LC-induced clastogenicity, Cr and not Pb is the proximate clastogenic species in human lung cells.