Methods for predicting carcinogenic hazards: new opportunities coming from recent developments in molecular oncology and SAR studies

Modelling mutagenicity using properties calculated by computational chemistry

The recent advances in combinatorial chemistry and high throughput screening technologies have led to an explosion in the numbers of possible therapeutic candidates being produced at the early stages of drug discovery. This rapid increase in the number of chemicals to be classified results in a greater need for alternative methods for the prediction of toxicity. Most QSAR models for mutagenicity have been constructed for congeneric series. The prediction requirements of the pharmaceutical industry, however, cover quite diverse chemical structures. This paper reports a study of mutagenicity data for a diverse set of 90 compounds. Good discriminant models have been built for this data set using properties calculated by the techniques of computational chemistry. Jack-knifed (leave one out) predictions for these models are of the order of 85%.

Diet, metabolic polymorphisms and dna adducts: the EPIC-Italy cross-sectional study

DNA adducts in peripheral leukocytes are considered a reliable indicator of internal dose exposure to genotoxic agents and, possibly, of cancer risk. We investigated their association with diet and other individual characteristics in healthy adults. The prospective study EPIC-Italy, a section of a larger European project, enrolled 47,749 men and women, aged 35-64 years, in 5 centres: all provided individual information about dietary and life-style habits and a blood sample. In a cross-sectional study, approximately 100 volunteers were randomly selected from each of the three main geographical study areas (Northern, Central and Southern Italy). DNA adducts and four polymorphic metabolic genotypes were determined in peripheral leukocytes by using (32)P-postlabelling technique and PCR methods. Among 309 subjects (153 men), 72.8% had detectable levels of DNA adducts (mean: 8.1 +/- 0.6 per 10(9) nucleotides). Strong negative associations emerged with the reported frequency of consumption of fresh fruit and vegetables, olive oil, and the intake of antioxidants. DNA adducts were higher in subjects with GSTT1 null genotype (p = 0.05). Significant differences between study centres emerged in multivariate analyses (mean levels: 11.0, 10.0, 7.2, 6.5 and 5.2 for Florence, Naples, Turin, Varese and Ragusa, respectively). A possible opposite seasonal variation was found according to latitude: adduct levels tended to be lower in winter in Florence and the southern centres, and during summer in the two northern centres. Frequent consumption of fresh fruit and vegetables is associated with reduced levels of DNA adducts, possibly contributing to the role of diet in modulating cancer risk.

Exposure to agrochemicals and DNA adducts in Western Liguria, Italy

Pesticides are used to control pests and improve agricultural production. Despite their selectivity of action, a number of agrochemicals have been reported to be genotoxic using the (32)P-DNA postlabeling assay. Greenhouse floriculturists are suspected of being heavily exposed to agrochemicals during loading, mixing, and application of pesticides, as well as during manual activities by continuous contact with flowers and ornamental plants. We analyzed the DNA adduct formations in the white blood cells (WBCs) of 57 nonsmoker greenhouse floriculturists and 33 nonsmoker age-matched referents residing in the Western Liguria Region, Italy-the most important Italian greenhouse floriculture area. The averages of DNA adducts, expressed as relative adduct labeling (RAL), were 8.50 x 10(9) +/- 1.98 (SE) in floriculturists and 2.17 x 10(9) +/- 1.05 (SE) in referents. DNA adducts were significantly higher in floriculturists than in controls after adjustment for age and gender (P = 0.007). A specific adduct pattern, with up to six different spots, was observed in 60% of floriculturists, while no adducts were generally detected in controls. Our study represents an important contribution to the correct evaluation of the potential health risk associated with floriculture activity and supports the adoption of measures ensuring pesticide exposure reduction in greenhouses.