Chromium (VI) induces both bulky DNA adducts and oxidative DNA damage at adenines and guanines in the p53 gene of human lung cells

Abstract

Chromium (VI) [Cr(VI)], a ubiquitous environmental carcinogen, is generally believed to induce mainly mutagenic binary and ternary Cr(III)-deoxyguanosine (dG)-DNA adducts in human cells. However, both adenine (A) and guanine (G) mutations are found in the p53 gene in Cr exposure-related lung cancer. Using UvrABC nuclease and formamidopyrimidine glycosylase (Fpg), and ligation-mediated PCR methods, we mapped the distribution of bulky DNA adducts (BDA) and oxidative DNA damage (ODD) in the p53 gene in Cr(VI)-treated human lung cells. We found that both BDA and ODD formed at 2'-deoxyadenosine (dA) and dG bases. To understand the causes for these Cr-induced DNA damages, we mapped the distribution of BDA adducts and ODD in the p53 gene DNA fragments induced by Cr(III), Cr(VI) and Cr(V), the three major cellular Cr forms. We found that (i) dA at -CA- is a major Cr(VI) binding site followed by -GG- and -G-. Cr(VI) does not bind to -GGG-, (ii) Cr(VI)-DNA binding specificity is distinctly different from the Cr(III)-DNA binding in which -GGG- and -GG- are preferential sites, (iii) Cr(V) binding sites include all of Cr(VI) and Cr(III)-DNA binding sites and (iv) Cr(VI) and Cr(V) induce Fpg-sensitive sites at -G-. Together, these results suggest that Cr(VI) induction of BDA and ODD at dA and dG residues is through Cr(V) intermediate. We propose that these Cr(VI)-induced BDA and ODD contribute to mutagenesis of the p53 gene that leads to lung carcinogenesis.

Scientific Opinion on the risks to public health related to the presence of chromium in food and drinking water

“…This last mutational spectrum is consistent with the mutagenicity of Cr(III)-derived DNA adducts as detected in single-lesion plasmids replicated in human cells (see above) and differs significantly from the spectra induced by known oxygen radicalproducing agents (H 2 O 2 , Fe 2+ and X-ray) analysed in the same study (Chen and Thilly, 1994). Although Cr(VI) is generally believed to induce dG-DNA adducts, both bulky DNA adducts and oxidative damage at adenines and guanines were recently (Arakawa et al, 2012) detected in the p53 gene in Cr(VI) treated human lung cells. The analysis of the binding sites for the three major cellular Cr forms, namely Cr(III), Cr(VI) and Cr(V), suggested that Cr(VI) induction of lesions at dA and dG residues is likely to be through Cr(V) intermediates.…”

Antioxidant Effect of Grape Seed Proanthocyanidin Extract against Potassium Dichromate Induced Oxidative DNA Damage in Small Intestine of Adult Male Albino Rats

“…This coincided with Hill et al (2008) and Banu et al (2011) who detected increase in the total p53 protein and p53 phosphorylation in human colon carcinoma cells and ovarian granulosa cells of chromium treated Sprague-Dawley rats. Arakawa et al (2012) also found mutation of p53 gene in Cr (VI)-treated human lung cells due to induction of oxidative DNA damage through Cr (V) intermediate.…”

The influence of potassium dichromate on growth and survival of the vermicomposting earthworm Eisenia foetida

“…The hydroxyl radicals and hydrogen peroxide produced during the reduction of Cr (VI) could be responsible for negative effects on survival of some stages in the earthworm. Arakawa et al (2012) demonstrated in vitro that Cr (III), Cr (VI) and Cr (V), the three major cellular Cr forms, induced bulky DNA adducts and oxidative DNA damage which contributed to mutagenesis of the p53 gene that leads to lung carcinogenesis.…”