Genotoxicity of trivalent chromium in bacterial cells. Possible effects on DNA topology.
Trivalent chromium is a metal required for proper sugar and fat metabolism. However, it has been suggested that it causes DNA damage in in vitro test systems, although in vivo toxicity has not yet been proved. In the present study, the effect of Cr3+ on bacterial cells was tested with the Pro-Tox (C) assay, and its cellular uptake was measured with flame atomic absorption spectroscopy. The potential genotoxicity of Cr3+ was further examined by the study of its influence on a bacterial type II topoisomerase. Cr3+ was shown to cause DNA damage and inhibit topoisomerase DNA relaxation activity, probably by preventing the formation of the covalent link between enzyme and double helix. In addition, Cr3+ decreases the viability and/or proliferation rate of eukaryotic cells such as murine B16 melanoma cells and human MCF-10A neoT ras-transformed human epithelial cells. The possible implication for Cr3+ intake by humans is discussed.
KRKA d.d., Research Department of New Entities, Novo mesto, Slovenia, University of Ljubljana, Biotechnical Faculty, Ljubljana, Slovenia.
Andreja
A
Plaper
Spela
S
Jenko-Brinovec
Ales
A
Premzl
Janko
J
Kos
Peter
P
Raspor
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002461:Cell Line, Transformed; D002470:Cell Survival / Q000187:drug effects; D002712:Chlorides / Q000633:toxicity; D017608:Chromium Compounds / Q000633:toxicity*; D004249:DNA Damage; D004269:DNA, Bacterial / Q000187:drug effects*; D019587:Dietary Supplements / Q000633:toxicity; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009566:Nitrates / Q000633:toxicity; D010070:Oxalates / Q000633:toxicity; D059005:Topoisomerase II Inhibitors; D014407:Tumor Cells, Cultured
D002712:Chlorides; D017608:Chromium Compounds; D004269:DNA, Bacterial; D009566:Nitrates; D010070:Oxalates; D059005:Topoisomerase II Inhibitors; C041167:chromium nitrate; C022990:chromic chloride