Influence of reducing compounds on the formation of DNA—protein cross-links in HL-60 cells induced by hexavalent chromium

Capellmann, Michaela; Mikalsen, Arne; Hindrum, Marit; Alexander, Jan

doi:10.1093/carcin/16.5.1135

Cited by 16 publications

(4 citation statements)

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“…Asc plays a dominant role in reductive activation of Cr(VI) in vivo , and it has been found to strongly enhance apoptotic, genotoxic, and mutagenic effects of Cr(VI) in human and rodent cells , . However, the role of this key reducer in the production of DPC by Cr(VI) remains poorly understood as previous studies attempted to deliver Asc into cells through inefficient approaches , that are associated with significant side effects . Under Asc-deficient culture conditions, human cells largely rely on GSH for Cr(VI) reduction .…”

Section: Resultsmentioning

confidence: 99%

Mechanism of DNA−Protein Cross-Linking by Chromium

Macfie

Hagan

Zhitkovich

2009

Chem. Res. Toxicol.

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Hexavalent chromium is a known inducer of DNA-protein crosslinks (DPC) that contribute to repression of inducible genes and genotoxicity of this metal. Lymphocytic DPC have also shown potential utility as biomarkers of human exposure to Cr(VI). Here, we examined the mechanism of DPC formation by Cr(VI) and the impact of its main cellular reducers. In vitro reactions of Cr(VI) with one-electron reducing thiols (glutathione, cysteine) or two-electron donating ascorbate were all efficient at DPC production, indicating a dispensable role of Cr(V). No Cr(VI) reducer was able to generate DPC in the presence of Cr(III)-chelating EDTA or phosphate. A critical role of Cr(III) in DNA-protein linkages was further confirmed by dissociation of Cr(VI)-induced DPC by phosphate. EDTA was very inefficient in DPC dissociation, indicating its poor suitability for testing of Cr(III)-mediated bridging and reversal of complex DPC. Reactions containing only one Cr-modified component (protein or DNA) showed that Cr(III)-DNA adduction was the initial step in DPC formation. Crosslinking proceeded slowly after the rapid formation of Cr-DNA adducts, indicating that protein conjugation was the rate-limiting step in DPC generation. Experiments with depletion of glutathione and restoration of ascorbate levels in human lung A549 cells showed that high cellular reducing capacity promotes DPC yield. Overall, our data provide evidence for a three-step crosslinking mechanism involving (i) reduction of Cr(VI) to Cr(III), (ii) Cr(III)-DNA binding and (iii) protein capture by DNA-bound Cr(III) generating protein-Cr(III)-DNA crosslinks.

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Section: Resultsmentioning

confidence: 99%

Mechanism of DNA−Protein Cross-Linking by Chromium

Macfie

Hagan

Zhitkovich

2009

Chem. Res. Toxicol.

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“… 77 Capellmann et al found that vitamin C reacted much faster with Cr(VI) at physiological pH than GSH did, suggesting an influence of the reaction velocity of the redox reaction between Cr(VI) and the reducing compounds on the toxification of Cr(VI) and formation of DPCs. 78 …”

Section: Chromium-carcinogenicity Chemopreventionmentioning

confidence: 99%

Carcinogenicity of chromium and chemoprevention: a brief update

Song

et al. 2017

OTT

205

103

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Chromium has two main valence states: hexavalent chromium (Cr[VI]) and trivalent chromium (Cr[III]). Cr(VI), a well-established human carcinogen, can enter cells by way of a sulfate/phosphate anion-transport system, and then be reduced to lower-valence intermediates consisting of pentavalent chromium (Cr[V]), tetravalent chromium (Cr[IV]) or Cr(III) via cellular reductants. These intermediates may directly or indirectly result in DNA damage or DNA–protein cross-links. Although Cr(III) complexes cannot pass easily through cell membranes, they have the ability to accumulate around cells to induce cell-surface morphological alteration and result in cell-membrane lipid injuries via disruption of cellular functions and integrity, and finally to cause DNA damage. In recent years, more research, including in vitro, in vivo, and epidemiological studies, has been conducted to evaluate the genotoxicity/carcinogenicity induced by Cr(VI) and/or Cr(III) compounds. At the same time, various therapeutic agents, especially antioxidants, have been explored through in vitro and in vivo studies for preventing chromium-induced genotoxicity/carcinogenesis. This review aims to provide a brief update on the carcinogenicity of Cr(VI) and Cr(III) and chemoprevention with different antioxidants.

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“…During this process, GSH may become reactive and bind to DNA [43,44]. Indeed, Cr (VI)-induced DNA-protein cross links increase in proportion to increasing GSH concentrations in cultured cells and cell-free systems [43,45,46]. When HP2 is present, the reduction of Cr (VI) by GSH also produces 0 2 0 and oOH, apurinic/apyrimidinic (AP) sites and DNA single-strand breaks [5,[47][48][49][50].…”

Section: Introductionmentioning

confidence: 99%

Effects of Glutathione on Chromium-induced DNA Crosslinking and DNA Polymerase Arrest

O’Brien

Patierno

2001

Molecular Mechanisms of Metal Toxicity and Carcinogenesis

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Hexavalent chromium (Cr (VI» is reduced intracellularly to Cr (V), Cr (IV) and Cr (III) by ascorbate (Asc), cysteine and glutathione (GSH). These metabolites induce a spectrum of genomic DNA damage resulting in the inhibition of DNA replication. Our previous studies have shown that treatment of DNA with Cr (III) or Cr (VI) plus Asc results in the formation ofDNA-Cr-DNA crosslinks (Cr-DDC) and guanine-specific arrests of both prokaryotic and mammalian DNA polymerases. GSH not only acts as a reductant ofCr (VI) but also becomes crosslinked to DNA by Cr, thus, the focus of the present study was to examine the role of GSH in Cr-induced DNA damage and polymerase arrests. Co-incubation of Cr (III) with plasmid DNA in the presence ofGSH led to the crosslinking ofGSH to DNA. GSH co-treatment with Cr (III) also led to a decrease in the degree ofCrinduced DNA interstrand crosslinks relative to Cr (III) alone, without affecting total Cr DNA binding. DNA polymerase arrests were observed following treatment of DNA with Cr (Ill) alone, but were markedly reduced when GSH was added to the reaction mixture. Pre-formed polymerase-arresting lesions (Cr-DDC) were not removed by subsequent addition of GSH. Treatment of DNA with Cr (VI), in the presence of GSH, resulted in crosslinking of GSH to DNA, but failed to produce detectable DNA interstrand crosslinks or polymerase arrests. The inhibitory effect of GSH on Cr-induced polymerase arrest was further confirmed in human genomic DNA using quantitative PCR (QPCR) analysis. Treatment of genomic DNA with Cr (III) resulted in a marked inhibition of the amplification of a 1.6 kb target fragment of the p53 gene by Taq polymerase. This was almost completely prevented by co-treatment with GSH and Cr (III). These results indicate that Cr-induced DNA interstrand crosslinks, and not DNA-Cr-GSH crosslinks, are the principal lesions responsible for blocking DNA replication. Moreover, the formation ofDNA-Cr-GSH crosslinks may actually preclude the formation of the polymerase arresting lesions. (Mol Cell Biochem 222: 173-182, 2001)

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Influence of reducing compounds on the formation of DNA—protein cross-links in HL-60 cells induced by hexavalent chromium

Cited by 16 publications

References 0 publications

Mechanism of DNA−Protein Cross-Linking by Chromium

Mechanism of DNA−Protein Cross-Linking by Chromium

Carcinogenicity of chromium and chemoprevention: a brief update

Effects of Glutathione on Chromium-induced DNA Crosslinking and DNA Polymerase Arrest

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