S. Kanitz

Formation of adducts by bisphenol A, an endocrine disruptor, in DNA in vitro and in liver and mammary tissue of mice.

Endocrine disruptors (EDs) represent a major toxicological and public health issue, and the xenoestrogen bisphenol A (BPA) has received much attention due to its high production volume and widespread human exposure. Also, due to its similarity to diethylstilbestrol, a known human carcinogen, BPA has been investigated for its genotoxic and carcinogenic properties, but the results have been either inconclusive or controversial. Metabolically activated BPA has previously been shown to form DNA adducts both in vitro and in rat liver. The present study was designed (a) to assess the sensitivity threshold of DNA-adduct detection by 32P-postlabelling in an acellular system and (b) to evaluate the formation of DNA adducts in both liver and mammary cells of female CD-1 mice receiving BPA in their drinking water (200 mg/kg body weight) for eight consecutive days. The reaction of BPA with calf thymus DNA, in the presence of S9 mix, resulted in a dose-dependent formation of multiple DNA adducts, with a detection limit of approximately 10 ng of this ED under our experimental conditions. Administration of BPA to mice confirmed that DNA adducts are formed in liver (3.4-fold higher levels than in controls). In addition, new evidence is provided that DNA adducts are formed in target mammary cells (4.7-fold higher than in controls). Although DNA adducts do not necessarily evolve into tumours or other chronic degenerative diseases, the formation of these molecular lesions in target mammary cells may bear relevance for the potential involvement of BPA in breast carcinogenesis.

Exposure to active and passive smoking during pregnancy and severe small for gestational age at term

Objective. The objective of this study was to assess the relationship between active smoking as well as environmental tobacco smoke (ETS) exposure and severe small for gestational age (SGA) at term in a sample of pregnant Italian women. Methods. A case–control study was conducted in nine cities in Italy between October 1999 and September 2000. Cases of severe SGA were singleton, live born, at term children with a birth weight ≤ 5th percentile for gestational age. Controls (10:1 to cases) were enrolled from among singleton at term births that occurred in the same hospitals one or two days after delivery of the case, with a birth weight > 10th percentile for gestational age. A total of 84 cases of severe SGA and 858 controls were analyzed. A self-administered questionnaire was used to assess active smoking and ETS exposure, as well as potential confounders. Results. Multivariate logistic regression analysis showed a relationship between active smoking during pregnancy and severe SGA (adjusted odds ratio (OR) 2.10, 95% confidence interval (CI) 1.13–3.68). ETS exposure was associated with severe SGA (adjusted OR 2.51, 95% CI 1.59–3.95) with a dose–response relationship to the number of smokers in the home.

Pharmacological modulation of genome and proteome alterations in mice treated with the endocrine disruptor bisphenol A.

Among endocrine disruptors, the xenoestrogen bisphenol A (BPA) is of particular interest due to the very high production and widespread environmental contamination. We recently demonstrated that the oral administration of BPA to mice results in the formation of DNA adducts not only in liver but also in mammary tissue. The present study aimed at evaluating the modulation of BPA-related DNA adducts and proteome alterations by the chemopreventive agents budesonide (BUD) and phenethyl isothiocyanate (PEITC). Swiss ICR (CD-1) mice received, for 8 days, BPA with the drinking water and either chemopreventive agent with the diet. We measured DNA adducts by (32)P postlabeling and 656 proteins by antibody microarray. BPA induced the formation, with similar patterns, of DNA adducts in liver and in mammary tissue. Moreover, BPA dysregulated 13 proteins in mammary tissue, mostly in the sense of upregulation, including estrogen receptor-beta and proteins involved in cell proliferation, inhibition of apoptosis, tissue remodeling, inflammation, stress response, and glutathione synthesis. PEITC significantly inhibited the formation of BPA-induced DNA adducts, but only at the highest dose tested, and BUD was totally ineffective. The chemopreventive agents modulated a variety of BPA-induced changes in proteome profiles. However, as shown by both hierarchical cluster analysis and principal component analysis, BUD and especially PEITC were not able to restore the physiological situation in BPA-treated mice. Therefore, the in vivo use of proteome analysis proves to be a sensitive tool for the early prediction not only of protective effects but also of adverse effects of chemopreventive agents.