effects of different endocrine disruptor (edc) mixtures on gene expression in neonatal rat brain...

S106 Abstracts / Toxicology Letters 221S (2013) S59–S256

P08-24Effects of different endocrine disruptor (EDC)mixtures on gene expression in neonatal ratbrain regions: Focus on developing excitatorysynapses

Walter Lichtensteiger 1,∗, Catherine Bassetti-Gaille 1, OliverFaass 1, Julie Boberg 2, Sofie Christiansen 2, Ulla Hass 2, AndreasKortenkamp 3, Margret Schlumpf 1

1 GREEN Tox and Institute of Anatomy, University of Zurich, Zurich,Switzerland, 2 National Food Institute, Technical University ofDenmark, Søborg, Denmark, 3 Institute for the Environment, BrunelUniversity, Uxbridge, UK

Sexual brain differentiation is a potential EDC target. It dependson a combination of estrogen receptor- and androgen receptor-mediated effects in males and on estrogens in females. It isnot known how these processes are affected by real-worldmixtures of EDCs. We investigated the effect of three EDCmixtures on gene expression in developing brain. Amix (8 anti-androgenic chemicals), Emix (4 estrogenic chemicals) and Tmix(Amix + Emix + paracetamol recently identified as anti-androgenic)were administered by oral gavage to rat dams from gestationalday 7 until weaning, at doses corresponding to 450×, 200× and100× high end human intakes (S. Christiansen et al., 2012. Inter-national Journal of Andrology 35, 303). At postnatal day 6, duringthe last part of sexual brain differentiation, exon microarray anal-yses were performed in medial preoptic area (MPO) in the highestdose group, and real time RT PCR of selected mRNA species inMPO and ventromedial hypothalamus (VMH) of all dose groups.Microarray analyses revealed mixture- and sex-specific effects ongene expression patterns. The majority of genes affected by an indi-vidual mixture was selective for that mixture. Real time RT PCRof individual mRNAs demonstrated treatment- and sex-dependentdifferences between MPO and VMH. Effects were dose-dependent.Prominent are effects on the expression of genes involved in exci-tatory glutamatergic synapse formation and function. These dataindicate that effects of complex EDC mixtures on developing braincan be characterized by mixture-, sex- and region-specific geneexpression patterns. Excitatory synapse development emerged asa potentially relevant target.

http://dx.doi.org/10.1016/j.toxlet.2013.05.163

P08-25Effects of endocrine disruptors bisphenol A anddi(2-ethylhexyl) phthalate in a combinationwith 17�-estradiol on apoptosis-related genesin the MCF-7 breast cancer cell line

Alzbeta Mlynarcikova ∗, Tomas Havranek, Maria Fickova

Institute of Experimental Endocrinology SAS, Bratislava, Slowakia

The role of estrogen signaling in mammary carcinogenesis iswell established. Compounds named endocrine disruptors (EDs)can exert estrogen-like activities affecting hormone-controlledhomeostasis. Bisphenol A (BPA) and di(2-ethylhexyl) phthalate(DEHP) are employed in the manufacture of plastics for consumerproducts (food packaging, etc.). The correlation between increasedEDs exposure and cancer was shown, however, studies with breastcancer cells have yielded inconsistent data. BPA and DEHP canmimic the effects of 17�-estradiol (E2) through estrogen receptorsor may exert E2-independent actions. Besides mitogenic effects ofE2, its antiapoptotic action may contribute to its role in the can-

cer promotion. Since the breast tissue is simultaneously exposedto endogenous and exogenous agents, in the present study, thehuman breast cancer cells MCF-7 were exposed to E2, BPA/DEHP,or their combinations with E2 (all at concentrations 10−12, 10−9,10−6 M) for 24–120 h. The effects of combinations of E2 with BPAor DEHP on several apoptosis-related genes (Bcl-2, Bax, p53) wereanalyzed. The results indicate that BPA alone (10−9, 10−6 M) or incombination with E2 could reduce the expression of proapoptoticp53 and Bax genes. DEHP (10−6 M) was also able to down-regulateBax gene expression. The presence of E2 increased antiapoptoticBcl-2 transcripts. These data could partially explain our previousresults where the BPA + E2 combinations stimulated de novo DNAsynthesis and MCF-7 cell proliferation. Thus, the final proliferativeeffects induced by EDs in combinations with E2 in MCF-7 cells couldpartially result from the antiapoptotic action.

http://dx.doi.org/10.1016/j.toxlet.2013.05.164

P08-26Effects of formaldehyde exposure on humanepithelial cells all along the respiratory tract

Gaëlle Bardet ∗, Charles Persoz, Thomas Loret, Isabelle Momas,Sophie Achard, Nathalie Seta

Université Paris Descartes, Faculté de Pharmacie, EA4064 Impactsanitaire des pollutions, 75006 Paris, France

The respiratory tract is directly exposed to inhaled environmen-tal pollutants such as chemicals. Formaldehyde (FA) is a ubiquitousindoor air pollutant known as irritant. Some epidemiological stud-ies revealed an association between FA exposure at low levels andrespiratory diseases. Our aim was to assess the cellular inflamma-tory response to FA exposure at environmental levels of epithelialcells from different parts of the respiratory tract. For this purpose,alveolar A549, bronchial BEAS-2B cell lines and human nasal pri-mary cell cultures (hAECN; Epithelix®), were cultured on insertand exposed in air/liquid interface (Vitrocell System®), with air orFA (50 �g/m3) during 30 min for A549 and BEAS-2B and 60 minfor hAECN. 24 h after exposure, apical medium in which IL-8 andMCP-1 levels were measured (ELISA assay), was collected, and cel-lular viability was assessed by XTT assay. Whatever the conditionsand cell type, cell viability was unchanged. No significant variationin inflammatory response was noted after FA exposure comparedto air exposure for the A549, BEAS-2B cells while we observedan increase in IL8 for hAECN without any change in MCP-1. Ourresults suggest that hAECN is more appropriate as a cellular modelto mimic the effect of inhaled pollution, since it is a human primarycell culture, and not an immortalized cell line. Mainly nasal epithe-lium is first in line in contact with inhaled pollutants and the firstdefensive barrier, which makes this epithelium the most relevantwhen studying the response to these chemicals.

http://dx.doi.org/10.1016/j.toxlet.2013.05.165

P08-27Effects of maternal exposure todi(2-ethylhexyl)phthalate (DEHP) duringpregnancy on neonatal asthma susceptibility

Kyoung-youl Lee ∗, Eun-young Choi

Kongju National University, Chungnam, Korea

Di(2-ethylhexyl) phthalate (DEHP) is widely distributed in theenvironment and used as a plasticizer. In this study, we investigate