REPAIR OF DNA DAMAGE CAUSED BY FORMALDEHYDE IN HUMAN-CELLS

  • 1 January 1984
    • journal article
    • research article
    • Vol. 44  (10) , 4323-4327
Abstract
The alkaline elution technique was used to study repair of DNA damage caused by formaldehyde (HCHO) in human bronchial epithelial cells and fibroblasts, skin fibroblasts and DNA excision repair-deficient skin fibroblasts from donors with xeroderma pigmentosum. Exposure of cells to HCHO resulted in DNA-protein cross-links (DPC) and DNA single-strand breaks (SSB) in all cell types. DPC were induced at similar levels and were also removed by all cell types, with a half removal time of 2-3 h. HCHO caused more SSB in the normal cell types than in the xeroderma pigmentosum fibroblasts. In all cell types, including the xeroderma pigmentosum cells, HCHO-induced DNA SSB and DPC were removed at comparable rates. By excision repair of HCHO-induced DNA damage, normal cells generated SSB that were also readily repaired. HCHO was only moderately cytotoxic to normal bronchial epithelial cells and fibroblasts at concentrations that induced substantial DNA damage. HCHO enhanced the cytotoxicity of both ionizing radiation and N-methyl-N-nitrosourea in both cell types. Most DPC caused by HCHO can be removed without the involvement of DNA excision repair. Furthermore, HCHO also directly causes DNA SSB as well as SSB generated indirectly during UV-type excision repair. HCHO thus may enhance the cytotoxicity of chemical and physical carcinogens in human cells.

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