Chromium DNA adducts

Singh J, McLean JA, Pritchard DE, et al. 1998b. Sensitive quantitation of chromium-DNA adducts by inductively coupled plasma mass spectrometry with a direct injection high-efficiency nebulizer. Toxicological Sciences 46 260-265. 

Models which ascribe the induction of chromium-DNA adducts to chromium(V) and the generation of oxidative DNA damage including single-strand breaks to hydrogen peroxide are over-simplistic (Kortenkamp et al. 1996). A combination of GSH, molecular oxygen, and chromium(Vl) can damage DNA via non-Fenton pathways. 

Hexavalent chromium (6 ") is a recognized carcinogen, and industrial exposure to fiimes and dusts containing this metal is associated with increased incidence of lung cancer, dermatitis, and skin ulcers. Environmental health risks arise from soil contamination by Cr " waste disposal sites left by the leather tanning and dyestuff industries. Cr is more efficiently absorbed than Cr " and its toxicity and carcinogenic effects involve reduction to Cr and Cr " by cysteine, with the formation of intracellular DNA adducts. Cr species are relatively nontoxic partly because of their poor intestinal absorption and rapid excretion in urine. 

The only stable strontium compound known to be genotoxic is strontium chromate. Strontium chromate induced sister chromatid exchanges in Chinese hamster ovary cells in vitro (Venier et al. 1985). In the Ames test using the Salmonella typhimurium strain TA100, strontium chromate induced mutations in the presence, but not in the absence of S9 microsomes. The genotoxicity of strontium chromate is related to the ability of the hexavalent chromium ion to enter cells and become metabolized, forming a reactive DNA-adduct. Strontium only contributes to the solubility of the salt (Elias et al. 1989, 1991). 

Quievryn G, Peterson E, Messer J, Zhitkovich A. 2003. Genotoxicity and mutagenicity of chromium(Vr)/ascarbate-generated DNA adducts in human and bacterial cells. Biochemistry 42(4) 1062-1070. 

Bridgewater LC, Manning FCR, Woo ES, et al. 1994b. DNA polymerase arrest by adducted trivalent chromium. Mol Carcinogen 9 122-133. 

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