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Interaction of carcinogenic metal compounds with deoxyribonucleic acid repair processes
A Hartwig1, R Schlepegrell, H Dally
1Department of Biology and Chemistry, University of Bremen, Germany.
Abstract:
The potentials of nickel(II) and cadmium(II) to interfere with the repair of different types of deoxyribonucleic acid (DNA) lesions was investigated. Concerning the nucleotide excision repair pathway, nickel(II) has been shown to reduce the incision and the ligation frequency after ultraviolet (UV)-irradiation. When applying a gel mobility shift assay and HeLa nuclear cell free extracts, nickel(II) diminishes the specific binding of a protein to UV-damaged DNA, suggesting that nickel(II) interferes with the DNA-protein interactions involved in the damage recognition after UV-irradiation. Similarly, the incision frequency is reduced in the presence of low concentrations of cadmium(II). Concerning the repair of oxidative DNA damage induced by visible light, non-cytotoxic concentrations of nickel(II) caused a complete repair inhibition of DNA base modifications like 7,8-dihydro-8-oxoguanine (8-hydroxyguanine) and of DNA strand breaks. Since the repair of DNA damage is essential for the prevention of cancer, its inhibition may account for the carcinogenic action of the respective metal compounds.
Insights
Nickel and cadmium interfere with DNA repair mechanisms, potentially explaining their cancer-causing effects. These metals disrupt the cell
Area of Science:
- Environmental toxicology
- Molecular biology
- Cancer research
Background:
- DNA damage is constantly incurred from endogenous and exogenous sources.
- Efficient DNA repair mechanisms are crucial for preventing mutations and maintaining genomic stability.
- Certain metal ions are known environmental contaminants with potential genotoxic effects.
Purpose of the Study:
- To investigate the interference of nickel(II) and cadmium(II) with DNA repair pathways.
- To elucidate the molecular mechanisms by which these metals affect DNA lesion repair.
- To assess the implications of DNA repair inhibition for metal-induced carcinogenicity.
Main Methods:
- Investigated DNA repair inhibition using nucleotide excision repair assays.
- Utilized gel mobility shift assays with HeLa nuclear extracts to study DNA-protein interactions.
- Assessed the impact of metals on the repair of oxidative DNA damage, including base modifications and strand breaks.
Main Results:
- Nickel(II) reduced incision and ligation frequencies in UV-damaged DNA repair.
- Nickel(II) diminished specific protein binding to UV-damaged DNA, indicating interference with damage recognition.
- Cadmium(II) reduced DNA incision frequency at low concentrations.
- Nickel(II) completely inhibited the repair of oxidative DNA damage (8-hydroxyguanine and strand breaks) at non-cytotoxic concentrations.
Conclusions:
- Nickel(II) and cadmium(II) significantly interfere with critical DNA repair pathways.
- These metals disrupt DNA damage recognition and repair processes at the molecular level.
- Inhibition of DNA repair by nickel and cadmium may contribute to their carcinogenic potential.