Free Radical-Induced Damage to DNA: Mechanisms and Measurement
M. Dizdaroglu, Pawel Jaruga, M Birincioglu, H Rodriguez
Free radicals are produced in cells by cellular metabolism and by exogenous agents. These species react with biomolecules in cells including DNA. The resulting damage to DNA which is also called oxidative damage to DNA, is implicated in mutagenesis, carcinogenesis and aging. Mechanisms of damage involve abstractions and addition reactions by free radicals leading tocarbon-centered sugar radicals and OH- or H-adduct radicals of heterocyclic bases. Further reactions of these radicals yield numerous products. Various analytical techniques exist for the measurement of oxidative damage to DNA. Techniques that employ gas chromatography (GC) or liquid chromatography (LC) with mass spectrometry (MS) simultaneously measure numerousproducts, and provide positive identification and accurate quantification. The measurement of multiple products avoids misleading conclusions that might be drawn from the measurement of a single product, because product levels vary depending on reaction conditions and the redox status of cells. In the past, GC/MS was used for the measurement of modified sugar and bases,and DNA-protein cross-links. Recently, methodologies using LC/tandem MS (LC/MS/MS) and LC/MS techniques were introduced for the measurement of modified nucleosides. Artifacts might occur with the use of any of the measurement techniques. The use of proper experimental conditions might avoidartifactual formation of products in DNA. This article reviews mechanistic aspects of oxidative damage to DNA and recent developments in the measurement of this type of damage using chromatographic and mass spectrometric techniques.
Free Radical Biology and Medicine
8-Hydroxguanine, DNA repair, Formamidopyrimidines, GC/MS, LC/MS, Oxidative DNA damage