Oxidative DNA damage, antioxidants, and cancer

✍ Scribed by Andrew R. Collins

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 112 KB
• Volume: 21
• Category: Article
• ISSN: 0265-9247
• DOI: 10.1002/(sici)1521-1878(199903)21:3<238::aid-bies8>3.0.co;2-3

✦ Synopsis

Oxidised bases, such as 8-oxo-guanine, occur in cellular DNA as a result of attack by oxygen free radicals. The cancer-protective effect of vegetables and fruit is attributed to the ability of antioxidants in them to scavenge free radicals, preventing DNA damage and subsequent mutation. Antioxidant supplements (e.g., beta-carotene, vitamin C) increase the resistance of lymphocytes to oxidative damage, and a negative correlation is seen between antioxidant concentrations in tissues and oxidised bases in DNA. Large-scale intervention trials with beta-carotene have, however, led to increases in cancer. Recent measurements of the frequency of oxidised DNA bases indicate that earlier estimates were greatly exaggerated; there may be only a few thousand 8-oxo-guanines per cell. Convincing evidence for mutations resulting from oxidative damage, in tumours or cultured cells, is lacking. It seems that efficient antioxidant defences together with DNA repair maintain a steady-state level of damage representing minimal risk to cell or organism.