Electrochemical simulation of oxidation reactions involving nucleic acids
DNA damage has important implications in human health and may be responsible for the development of different diseases including cancer. Oxidation represents a key step in the alteration of the genetic material responsible for mutagenesis, genotoxicity, and/or cancerogenesis. Oxidation reactions produce reactive electrophiles that covalently bind to nucleic acid molecules. One class of reactive electrophiles are reactive oxygen species (ROS); the other ones are (bio)activated small molecules.
A number of in vitro tests using different bacterial and mammalian cell lines and in vivo tests mainly using rodents are available to identify compounds that induce genetic damage. Despite considerable success, problems regarding sensitivity are often encountered with these assays due to insufficient metabolic activation, side reactions with biological material (e.g. proteins), transport effects or DNA protection. We want to overcome these limitations with a “pure” instrumental method based on on-line electrochemistry (EC) - liquid chromatography (LC) - mass spectrometry (MS) aimed for testing the reactivity of synthetic nucleic acids with chemicals including tentative mutagenic compounds and ROS. EC is used to mimic biooxidation processes; formed reaction products are separated by LC, which facilitates their consecutive detection and characterization with MS.
Nucleic acids tested include nucleosides and nucleotides as well as small oligomers. Thus, EC/LC/MS should even be capable to study site-selectivity of reaction, necessary to discover mutational hotspots. Transformation products will be characterized with high performance MS and tandem MS to elucidate their structure. Identified lesions will represent putative biomarkers for studying the relationship between exposure and the development of diseases.
We expect to gain new insights into the mechanisms guiding the reactivity between nucleic acids and (activated) molecules. The derived reaction principles will be beneficial in medical, pharmaceutical and toxicological research for risk assessment and disease prevention and might stimulate the development of new drugs (e.g. antitumor drugs, chemopreventive antioxidants).
Grant
Austrian Science Fund (FWF): Simulation of redox processes involving nucleic acids, Project P 22526-B11, 2010-2013.
