Description of work
The project will attempt to investigate mechanisms of ochratoxin A-tumorigenicity and biomarkers of effects at two different levels
- in animals in vivo
- in animal and human tissues or appropriate cell systems.
Obtaining information on ochratoxin A-derived DNA-adducts and their structures and the role of oxidative stress, cell proliferation, molecular changes in gene expression, morphologic and cytogenetic changes in rats exposed to ochratoxin A for a prolonged time. Dose and exposure-time related changes will be quantified. The methods used here are focusing on structure elucidation and quantitation of low amounts of these adducts using modern mass spectrometry (AC/MS and LC/MS-MS).
Characterizing the type of DNA-damage induced by ochratoxin A in relevant cell culture systems. In addition the induction of mutation in tumorsuppressor genes will be investigated. This work is complemented by analysis of mutations in tumors. In addition, the induction of mutations in marker genes will be studied. In the second area, modern molecular biology and molecular genetics are applied to a toxicological problem. The biotransformation of ochratoxin A in vitro is relevant to obtain extent of metabolite formation and structures. The structures elucidated will be used to predict chemistry of possible DNA-adducts, the determination of enzymes responsible for ochratoxin A-biotransformation should help in improving or supplement the methods for genotoxicity testing. In general, a considerable synergy exists between the individual projects and samples generated by one partner will often be analysed for specific endpoints by one or more partners.
The research in the project will result in an improved understanding of mechanisms resulting in DNA-damage and their contribution to tumor induction by ochratoxin A should be obtained and should serve as a basis for establishing scientifically sound maximum permitted levels for ochratoxin A within EU. The results of this project will be used by EU regulatory and standardisation bodies, food authorities and industrial end-users for a science-based risk assessment for ochratoxin A.