Toxicology Letters 202 (2011) 161–167 Contents lists available at ScienceDirect Toxicology Letters journal homepage: www.elsevier.com/locate/toxlet Research paper Aflatoxin B1 – a potential endocrine disruptor – up-regulates CYP19A1 in JEG-3 cells Markus Storvik a,1 , Pasi Huuskonen a,1 , Taija Kyllönen a , Sarka Lehtonen b , Hani El-Nezami c , Seppo Auriola a , Markku Pasanen a,∗ a School of Pharmacy, University of Eastern Finland, FIN-70211, Kuopio, Finland b A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FIN-70211, Kuopio, Finland c School of Biological Sciences, University of Hong Kong, Hong Kong, China article info Article history: Received 29 November 2010 Received in revised form 26 January 2011 Accepted 31 January 2011 Available online 4 February 2011 Keywords: Aflatoxin B1 Aflatoxicol Aromatase Endocrine disruptor JEG-3 Placenta abstract Previous studies have indicated that aromatase (CYP19A1) is involved in the metabolism of aflatoxin B1 (AFB1). We hypothesized that exposure to AFB1 contaminated food during pregnancy could disrupt the normal production of steroid hormones in placenta. We examined the capability of AFB1 exposure to disrupt CYP19A1 expression as a putative endocrine disrupter, and to investigate the metabolism of AFB1 by CYP19A1. JEG-3 cells, as model for placental cells, were exposed alone and in combination to AFB1 and estrogen receptor ligands for 24–96 h. AFB1 (0.3–1.0 M) induced the expression of CYP19A1 by 163%–339% compared to control at the 96 h time point, although no induction was observed at 24 h. AFB1 concentrations higher than 1 M were cytotoxic to JEG-3 cells, and the cytotoxicity was inhibited by the aromatase inhibitor, finrozole. AFB1 was metabolized to aflatoxicol (AFL) by JEG-3 cells and CYP19A1 recombinant protein. AFL formation was partially inhibited by addition of tamoxifen and finrozole to the JEG-3 cells. AFB1 had no effect on the expression of CYP1A2 and CYP3A4 in JEG-3 cells. These results reveal that AFB1 can affect the expression of aromatase enzyme, indicating that chronic exposure to AFB1 may cause endocrine disruption in the foetoplacental unit. © 2011 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Placenta has metabolic and endocrine functions, and these func- tions can be affected by endogenous and xenobiotic compounds present in the maternal circulation. The expression of steroid metabolizing enzymes in placenta can be disrupted by a variety of xenobiotic pollutants, including cigarette smoke (Huuskonen et al., 2008) and maternal drug abuse (Paakki et al., 2000) and ambient air pollutants (Obolenskaya et al., 2010). Thus far, most studies exam- ining the hormonal functions on the human foetoplacental unit have been carried out in countries where the environmental impact or nutritional hazardous effects are minimized. In countries with less well developed hygiene standards the chemical stress in foe- toplacental unit may be high, which then may evoke alterations in metabolizing capacity. In Africa, South East Asia and South America exposure to crops contaminated by mould containing aflatoxin B1 ∗ Corresponding author at: School of Pharmacy, Faculty of Health Sciences, Uni- versity of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland. Tel.: +358 40 7199 346; fax: +358 17 162 424. E-mail address: markku.pasanen@uef.fi (M. Pasanen). 1 These two authors share the first authorship. (AFB1) is a major public health problem (Abdulrazzaq et al., 2002, 2004; Polychronaki et al., 2006). AFB1 is well known as a mycotoxin and carcinogen, often present as a contaminant in grains and nuts (IARC, 2002). AFB1 requires metabolic activation in order to elicit its carcinogenic properties. The carcinogenicity of AFB1 is mainly attributable to the metabolite AFB-8,9-epoxide which can bind to DNA. The other known metabolites include carcinogenic metabolites aflatoxin M1, P1, Q1 and aflatoxicol (AFL) (Salhab and Edwards, 1977; Wong and Hsieh, 1976). AFB1 is metabolized mainly by cytochrome P450 (CYP) enzymes CYP1A2 and CYP3A isoforms into several metabo- lites (Eaton and Gallagher, 1994; Guengerich et al., 1998; IARC, 2002) in adult liver (Gallagher et al., 1994; IARC, 2002). It is also known that neither CYP1A2 nor CYP3A4-7 is active in placenta at term (Hakkola et al., 1996a,b; Myllynen et al., 2007). Additionally, high AFB1 concentrations in umbilical cord have been associated with low birth weight, kernicterus, and in some cases also with death of the foetus (Abdulrazzaq et al., 2002, 2004). Furthermore, in a recent perfusion study, aflatoxicol was the only metabolite detected in placental perfusion models, and it was demonstrated that AFB1 is transferred through the placenta (Partanen et al., 2010). The formation of AFL is reported to be mediated by a NADPH- dependent reductase (Fig. 1.) (Salhab and Edwards, 1977). In the 0378-4274/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.toxlet.2011.01.028