European Parliament Pilot Project on Exposure to Indoor air Chemicals and Possible Health Risks

This report outlines the results of the 2-year pilot project on indoor air quality and potential health effects executed by the Joint Research Centre and funded by the European Parliament via the Directorate-General Health and Consumer Protection. It had four distinct objectives as follows: 1) to identify and quantify the main air pollutants present in public buildings, including indoor environments where children frequently stay, like schools and kindergartens, 2) to identify the main sources of these pollutants, applying source apportionment analyses, 3) to estimate people¿s exposure to these pollutants while working and/or living in these areas and combined with micro-environmental activity patterns during the day, 4) to evaluate possible health risks due to (chronic) exposure to air pollutants, in particular, for children. The results indicate that indoor air pollution concentrations are consistently higher than the respective outdoor ones for the chemical families this study focused on. Differences attributable to variation in consumer behaviour, climate and type of building materials used, have been identified in the indoor:outdoor ratio of primary pollutants across Europe. These differences account for small variance in the corresponding health risk to the local population across the EU.JRC.I.5-Physical and chemical exposure

Relationship between p53 and p27 expression following HER2 signaling

HER2, frequently associated with low p27 expression in breast tumors, when activated has been found to upmodulate p53 in tumor cells. The aim of this work was to investigate the role of p53 in the connection between HER2 and p27. Fifty-two breast tumor specimens, characterized for p53 mutations, were analyzed immunohistochemically (IHC) for HER2, p53 and p27 expression. p27, inversely associated with HER2, was found in 29% of tumors with IHC-negative mutated p53 versus 93% of tumors with accumulation of p53 protein and 59% with wild-type p53 (p=0.001), indicating a direct association between p53 and p27 expression. HER2-overexpressing cell lines carrying wild-type or null p53 protein, and treated with heregulin beta1 (HRG), were analyzed for expression and subcellular localization of p53 and p27. In HER2-overexpressing cells stimulated with HRG, p27 protein expression increased in parallel with p53 with no corresponding increase in p27 transcript. No p27 increase was observed in p53-null cells. Transfection with wild-type p53 restored p27 upmodulation in HRG-stimulated cells, indicating a crucial role of p53 in determining p27 upmodulation following HER2 activation. Together, our data demonstrate the crucial role of p53 in determining p27 upmodulation following HER2 activation. This could have implications in the response to Transtuzumab therapy

The arsenic in mice as experimental model for risk modifiers.

Studies on the relevance of host factors in modulating the physiological responses following chronic exposure to xenobiotics were carried out according to a \u201cToxicogenomic Model on Arsenic in Mice\u201d developed at thte JRC. This model is focused on chronic exposure to arsenate given alone or in combination with other xenobiotics, to assess potential \u201ccocktail effects\u201d and related cumulative risks. DNA-macroarrays technology is applied to evaluate physiological responses at transcriptional level and assessing possible biochemical responses. A cluster of 1200 cancer genes was used for screening purposes, while quantitative PCR on selected genes applied for validation. The exposure varied from in-utero and post-lactation up to adult age (4 months), the chemical forms (arsenate and dimethylarsenate) and doses from 0.1 up to 10 mg As/L in drinking water. Comparison between acute single doses and chronic exposure was also performed. Chronic exposure to arsenate and atrazine in drinking water was selected as an example of multiple chronic exposure. The liver, kidney, lung, bone marrow, adrenals, uterus, and testis were the tissues considered. In the tissues of mice chronically exposed to arsenate, the modulation of gene expression was not only depending on the levels, types and length of exposure, while differently regulated also by the sex, age and diet. The main gene functional families modulated were covering a wide range of biochemical and physiological regulations, like cell cycle modulation, cell adhesion, apoptosis, xenobiotic metabolism, DNA repair, protein turnover, and proto-oncogenes. The patterns of gene expression were strongly influenced by co-exposure to other xenobiotics like atrazine and naphthalene, particularly for genes involved in the metabolism and in neuroendocrine regulation. These effects varied according to the tissue considered, supporting the needs for coherent and specifically designed studies to assess relevant biomarkers of long-term exposure to low levels of xenobiotics and their mixtures

Sex as a major determinant of gene expression in tissues of mice exposed to arsenate.

Inorganic arsenic, frequently found as contaminant of ground water used for drinking purposes in many areas of the world, is a well-known potent human toxicant and carcinogen. Chronic exposure to inorganic arsenic has been associated with cancer of skin, lung, bladder and kidney and, probably, liver. The mechanism of arsenic action in vivo is poorly understood, in particular in relation to dose, type of tissue and gender. To elucidate tissue- and gender dependent biological responses in the genome of mice, we have used cDNA macroarrays for investigation on the expression of 1185 cancer-related genes in mice after exposure to arsenate in drinking water. Continuous exposures of mice to arsenate in drinking water modulate the gene expression in tissues. Interestingly, there were remarkable sex differences: male and female mice show completely different changes in the expression of cancer-related genes. The main gene functional families modulated, were covering a wide range of biochemical and physiological regulations, like cell cycle modulation, cell adhesion, apoptosis, xenobiotic metabolism, DNA repair, protein turnover and proto-oncogens. This result demonstrates important gene-environmental interactions: the molecular mechanisms triggered by arsenic levels frequently experienced following exposure via drinking water, are totally different in males and females. The results obtained using cancer-related genes will be compared with the profiles of over 30.000 genes using the Applied Biosystems expression Array System, to clarify the sex-specific gene pathways

Dietary proteins modulates the gene expression in mice chronically exposed to arsenate.

In the frame of a project on the assessment of risk modifying factors modulating the health effects of environmental chemicals we are developing a toxicogenomic approach using an \u201carsenic in mice\u201d experimental model, considering multistressors exposure, genetics, age, levels and length of exposure, etc. In the present study, we used cDNA Macroarrays to investigate the effects of low protein intake on the expression of 1185 cancer-related genes in the liver of male and female mice transplacentary exposed to different levels of arsenate in drinking water during gestation and developmental age. The results of this study support the relevance of dietary factors in modulating the physiological responses in gene expression following chronic exposure to xenobiotics. In mice chronically exposed to arsenate in drinking water, the modulation of gene expression in different tissues was not only depending on the levels of the xenobiotic under investigation, but mainly regulated by the content of proteins in diet

Clonogenicity and gene expression modulation in the bone marrow of mice chronically exposed to arsenic and atrazine.

The clonogenicity of myeloid progenitors (CFU-GM) and the modulation of gene expression of 1185 cancer-related genes by DNA-macroarrays in bone marrow were used to investigate in male and female mice the combined effects of continuous exposure to arsenate and atrazine in drinking water. In male mice, the exposure to arsenate or to atrazine alone and the combined exposure did not change the clonogenicity of the progenitors. In females the percentage of CFU-GM decreased significantly after atrazine exposure, did not change with arsenic treatment, but dramatically increased after the combined exposure to the two chemicals. Results from microarrays indicate that atrazine alone didn\u2019t stimulate the expression of any of the cancer genes analyzed in both male and female. Arsenic induced gene expression modulation only in female and had no effects on male. Major significant changes on the gene expression in bone marrow cells resulted following the co-exposure to arsenic and atrazine in both male and female. These results indicate that co-exposure of mice to atrazine and arsenate induces significant effects at the level of transcriptional activation of genes in bone marrow cells, as well as stimulating the myeloid progenitors to proliferate, particularly when co-administered in drinking water to female mice

Combined in-utero and juvenile exposure of mice to arsenate and atrazine in drinking water modulates the gene expression and clonogenicity of myeloid progenitors in bone marrow.

Increasing evidence proves that human fetuses are exposed to multiple risk factors and major concerns have been expressed towards exposure to potential endocrine modulating chemicals at early stage of life and during growth. Understanding that exposures occur as mixture of chemicals and that they converge on other inherent and environmental risk-modulating factors, there is a need to develop experimental models to assess the effects of exposure to multiple chemicals during different stage of life. In the present study, the clonogenicity of myeloid progenitors (CFU-GM) and the modulation of gene expression of 1197 cancer-related genes (DNA macroarrays) in bone marrow were used to investigate in male and female young mice the combined effects of continuous exposure to arsenate and atrazine in drinking water. Female adult mice were treated with arsenate in drinking water (1 mg As/L) for 10 days before mating and during the gestation. Offspring were randomly put into separate groups of males and females. One group of arsenic exposed offspring were exposed for 4 months to atrazine (1mg Atr/L) and arsenate (1 mg As/L) in drinking water (As+Atr). One group of each of arsenic unexposed offspring were exposed for 4 months to atrazine (1mg Atr/L) in drinking water (Atr). Additional arsenate (1 mg As/L) was given to one group of arsenic exposed offspring (As). Control mice without any treatment were also analysed (Ctrl). In male mice the exposure to arsenate or to atrazine alone did not result in significant changes on the gene expression in bone marrow cells, whereas, co-exposure to arsenic and atrazine (As+Atr) resulted in a significant up-modulation of gene expression. The percentage of CFU-GM weakly decreased after exposure to individual compounds, while the co-exposure did not change the clonogenicity of the progenitors. In female mice, the co-exposure to both chemicals resulted in a drastic up-modulation of gene expression, while in these cells the single treatments showed a up-modulation of few genes as well. The percentage of CFU-GM decreased significantly after atrazine exposure, did not change with arsenic treatment, but dramatically increased after the combined administration. These results indicate that in-utero and juvenile co-exposure of mice to atrazine and arsenate induce significant effects at the level of transcriptional activation of genes in bone marrow cells, as well as stimulating the myeloid progenitors to proliferate, particularly when co-administered in drinking water to female mice