Disturbance of DNA damage recognition after UV-irradiation by nickel(II) and cadmium(II) in mammalian cells

• Published in: Carcinogenesis (New York) 1998-04, Vol.19 (4), p.617-621
• Main Authors: HARTMANN, M, HARTWIG, A
• Format: Article
• Language: English
• Subjects: Binding Sites; Biological and medical sciences; Cadmium - pharmacology; Carcinogenesis, carcinogens and anticarcinogens; Cell-Free System; Chemical agents; DNA Damage; DNA Repair; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - metabolism; HeLa Cells; Humans; Medical sciences; Molecular Weight; Nickel - pharmacology; Tumors; Ultraviolet Rays
• ISSN: 0143-3334; 1460-2180; 1460-2180
• DOI: 10.1093/carcin/19.4.617

Nickel(II) and cadmium(II) have been shown previously to inhibit the incision step of nucleotide excision repair. By applying a gel-mobility-shift assay and HeLa nuclear extracts the effect of both metals on the damage recognition step of the repair process was investigated. Two proteins of 34 and 40 kDa were identified that bind with high affinity to a UV-irradiated synthetic oligonucleotide. When applying nuclear extracts from HeLa cells treated with 50 microM nickel(II) and higher, there was a dose-dependent decrease in protein binding; this effect was largely reversible by the addition of magnesium(II) to the binding reaction. In the case of cadmium(II), a dose-dependent inhibition of DNA-protein interactions was detected at 0.5 microM and higher, which was almost completely reversible by the addition of zinc(II). Therefore, compounds of both metals disturb DNA-protein interactions essential for the initiation of nucleotide excision repair most likely by the displacement of essential metal ions.