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  • 1.
    Asnake, Solomon
    et al.
    Örebro University, School of Science and Technology.
    Pradhan, Ajay
    Örebro University, School of Science and Technology.
    Banjop-Kharlyngdoh, Joubert
    Örebro University, School of Science and Technology.
    Modig, Carina
    Örebro University, School of Science and Technology.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    1,2-dibromo-4-(1,2 dibromoethyl) cyclohexane (TBECH)-mediated steroid hormone receptor activation and gene regulation in chicken LMH cells2014In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 33, no 4, p. 891-899Article in journal (Refereed)
    Abstract [en]

    The incorporation of brominated flame retardants into industrial and household appliances has increased their occurrence in the environment, resulting in deleterious effects on wildlife. With the increasing restraints on available compounds, there has been a shift to using brominated flame retardants that has seen the production of alternative brominated flame retardants such as 1,2-dibromo-4-(1,2 dibromoethyl) cyclohexane (TBECH), which has been detected in the environment. In previous in silico and in vitro studies the authors have shown that TBECH can activate both the human androgen receptor (hAR) and the zebrafish AR (zAR) suggesting that it is a potential endocrine disruptor. The present study was aimed at determining the interaction of TBECH with the chicken AR (cAR). In the present study, TBECH bound to cAR, but in vitro activation assay studies using the chicken LMH cell line showed it had a potency of only 15% compared with testosterone. Sequence difference between ARs from different species may contribute to the different responses to TBECH. Further quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) analysis showed that TBECH interacted with and altered the expression of both thyroid receptors and estrogen receptors. In addition, the qRT-PCR analysis showed that TBECH altered the transcription pattern of genes involved in inflammatory, apoptotic, proliferative, DNA methylation, and drug-metabolizing pathways. This demonstrates that TBECH, apart from activating cAR, can also influence multiple biological pathways in the chicken.

  • 2.
    Asnake, Solomon
    et al.
    Örebro University, School of Science and Technology.
    Pradhan, Ajay
    Biology, The Life Science Center, School of Science and Technology, Örebro University, Örebro, Sweden.
    Kharlyngdoh, Joubert Banjop
    Örebro University, School of Science and Technology.
    Modig, Carina
    Örebro University, School of Science and Technology.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    The brominated flame retardants TBP-AE and TBP-DBPE antagonize the chicken androgen receptor and act as potential endocrine disrupters in chicken LMH cells2015In: Toxicology in Vitro, ISSN 0887-2333, E-ISSN 1879-3177, Vol. 29, no 8, p. 1993-2000Article in journal (Refereed)
    Abstract [en]

    Increased exposure of birds to endocrine disrupting compounds has resulted in developmental and reproductive dysfunctions. We have recently identified the flame retardants, ally1-2,4,6-tribromophenyl ether (TBP-AE), 2-3-dibromopropy1-2,4,6-tribromophenyl ether (TBP-DBPE) and the TBP-DBPE metabolite 2-bromoallyI-2,4,6-tribromophenyl ether (TBP-BAE) as antagonists to both the human androgen receptor (AR) and the zebrafish AR. In the present study, we aimed at determining whether these compounds also interact with the chicken AR. In silico modeling studies showed that TBP-AE, TBP-BAE and TBP-DBPE were able to dock into to the chicken AR ligand-binding pocket. In vitro transfection assays revealed that all three brominated compounds acted as chicken AR antagonists, inhibiting testosterone induced AR activation. In addition, qRT-PCR studies confirmed that they act as AR antagonists and demonstrated that they also alter gene expression patterns of apoptotic, anti-apoptotic, drug metabolizing and amino acid transporter genes. These studies, using chicken LMH cells, suggest that TBP-AE, TBP-BAE and TBP-DBPE are potential endocrine disrupters in chicken.

  • 3.
    Asnake, Solomon
    et al.
    Örebro University, School of Science and Technology.
    Pradhan, Ajay
    Örebro University, School of Science and Technology.
    Kharlyngdoh, Joubert Banjop
    Örebro University, School of Science and Technology.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    The brominated flame retardants TBP-AE and TBP-DBPE antagonize the chicken androgen receptor and alter gene expression in chicken LMH cellsManuscript (preprint) (Other academic)
  • 4.
    Banjop Kharlyngdoh, Joubert
    Örebro University, School of Science and Technology.
    Modulation of androgen receptor function by brominated flame retardants2015Doctoral thesis, comprehensive summary (Other academic)
    List of papers
    1. Identification of a group of brominated flame retardants as novel androgen receptor antagonists and potential neuronal and endocrine disrupters
    Open this publication in new window or tab >>Identification of a group of brominated flame retardants as novel androgen receptor antagonists and potential neuronal and endocrine disrupters
    Show others...
    2015 (English)In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 74, p. 60-70Article in journal (Refereed) Published
    Abstract [en]

    Brominated flame-retardants (BFRs) are used in industrial products to reduce the risk of fire. However, their continuous release into the environment is a concern as they are often persistent, bioaccumulating and toxic. Information on the impact these compounds have on human health and wildlife is limited and only a few of them have been identified to disrupt hormone receptor functions. In the present study we used in silico modeling to determine the interactions of selected BFRs with the human androgen receptor (AR). Three compounds were found to dock into the ligand-binding domain of the human AR and these were further tested using in vitro analysis. Allyl 2,4,6-tribromophenyl ether (ATE), 2-bromoallyl 2,4,6-tribromophenyl ether (BATE) and 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE) were observed to act as AR antagonists. These BFRs have recently been detected in the environment, in house dust and in aquatic animals. The compounds have been detected at high concentrations in both blubber and brain of seals and we therefore also assessed their impact on the expression of L-type amino acid transporter system (LAT) genes, that are needed for amino acid uptake across the blood-brain barrier, as disruption of LAT gene function has been implicated in several brain disorders. The three BFRs down-regulated the expression of AR target genes that encode for prostate specific antigen (PSA), 5. α-reductases and β-microseminoprotein. The potency of PSA inhibition was of the same magnitude as the common prostate cancer drugs, demonstrating that these compounds are strong AR antagonists. Western blot analysis of AR protein showed that ATE, BATE and DPTE decreased the 5. α-dihydrotestosterone-induced AR protein levels, further confirming that these BFRs act as AR antagonists. The transcription of the LAT genes was altered by the three BFRs, indicating an effect on amino-acid uptake across cellular membranes and blood-brain barrier. This study demonstrated that ATE, BATE and DPTE are potent AR antagonists and the alterations in LAT gene transcription suggest that these compounds can affect neuronal functions and should be considered as potential neurotoxic and endocrine disrupting compounds.

    Keywords
    Gene regulation; Human; PSA; LAT
    National Category
    Environmental Sciences
    Research subject
    Biology
    Identifiers
    urn:nbn:se:oru:diva-41508 (URN)10.1016/j.envint.2014.09.002 (DOI)000346681700008 ()25454221 (PubMedID)2-s2.0-84908626070 (Scopus ID)
    Funder
    Knowledge Foundation, 20110183
    Note

    Funding Agency:

    Örebro University J61900

    Available from: 2015-01-14 Created: 2015-01-14 Last updated: 2017-12-05Bibliographically approved
    2. The brominated flame retardant TBECH activates the zebrafish (Danio rerio) androgen receptor, alters gene transcription and causes developmental disturbances
    Open this publication in new window or tab >>The brominated flame retardant TBECH activates the zebrafish (Danio rerio) androgen receptor, alters gene transcription and causes developmental disturbances
    2013 (English)In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 142, p. 63-72Article in journal (Refereed) Published
    Abstract [en]

    Tetrabromoethylcyclohexane (TBECH) is a brominated flame retardant that has been shown to be a potent agonist to the human androgen receptor (AR). However, while it is present in the environment, it is not known if it interacts with AR from aquatic species. The present study was therefore aimed at improving our understanding of how TBECH affects aquatic animals using zebrafish as a model organism. In silica modeling demonstrated that TBECH diastereomers bind to the zebrafish androgen receptor (zAR) and in vitro and in vivo data showed that TBECH has androgenic properties. Deleterious effects of TBECH were studied on embryonic and juvenile zebrafish and qRT-PCR analysis in vitro and in vivo was performed to determine TBECH effects on gene regulation. TBECH was found to delay hatching at 1 mu M and 10 mu M doses while morphological abnormalities and juvenile mortality was observed at 10 mu M. The qRT-PCR analysis showed alterations of multiple genes involved in chondrogenesis (cartilage development), metabolism and stress response. Thus, TBECH induces androgenic activity and has negative effects on zebrafish physiology and therefore its impact on the environment should be carefully monitored. (C) 2013 Elsevier B.V. All rights reserved.

    Keywords
    Androgens, Endocrine, Endocrine disruptor, Gene regulation
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:oru:diva-32902 (URN)10.1016/j.aquatox.2013.07.018 (DOI)000328093900007 ()23958786 (PubMedID)
    Funder
    Knowledge Foundation
    Available from: 2014-01-02 Created: 2014-01-02 Last updated: 2017-12-06Bibliographically approved
    3. Androgen receptor mutations associated with prostate cancer lead to differential activation by DBE-DBCH diastereomers
    Open this publication in new window or tab >>Androgen receptor mutations associated with prostate cancer lead to differential activation by DBE-DBCH diastereomers
    (English)Manuscript (preprint) (Other academic)
    Keywords
    steroid hormone receptor, endocrine disruptor, human carcinoma, androgen agonists
    National Category
    Biological Sciences
    Research subject
    Biology
    Identifiers
    urn:nbn:se:oru:diva-44665 (URN)
    Available from: 2015-05-20 Created: 2015-05-20 Last updated: 2017-10-17Bibliographically approved
    4. Combination effects on human cell lines following exposure to brominated flame-retardants that interact with the androgen receptor
    Open this publication in new window or tab >>Combination effects on human cell lines following exposure to brominated flame-retardants that interact with the androgen receptor
    (English)Manuscript (preprint) (Other academic)
    Keywords
    DBE-DBCH/TBECH, TBP-AE/ATE, TBP-BAE/BATE, TBP-DBPE/DPTE, endocrine disruptors, PSA, steroidogenesis
    National Category
    Biological Sciences
    Research subject
    Biology
    Identifiers
    urn:nbn:se:oru:diva-44666 (URN)
    Available from: 2015-05-20 Created: 2015-05-20 Last updated: 2017-10-17Bibliographically approved
  • 5.
    Banjop Kharlyngdoh, Joubert
    et al.
    Örebro University, School of Science and Technology.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    Combination effects on human cell lines following exposure to brominated flame-retardants that interact with the androgen receptorManuscript (preprint) (Other academic)
  • 6.
    Banjop Kharlyngdoh, Joubert
    et al.
    Örebro University, School of Science and Technology.
    Pradhan, Ajay
    Örebro University, School of Science and Technology.
    Asnake, Solomon
    Örebro University, School of Science and Technology.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    Androgen receptor mutations associated with prostate cancer lead to differential activation by DBE-DBCH diastereomersManuscript (preprint) (Other academic)
  • 7.
    Banjop-Kharlygdoh, Joubert
    et al.
    Örebro University, School of Science and Technology.
    Pradhan, Ajay
    Örebro University, School of Science and Technology.
    Asnake, Solomon
    Örebro University, School of Science and Technology.
    Walstad, Anders
    Örebro University, School of Science and Technology.
    Ivarsson, Per
    ALS Laboratory Group, Analytical Chemistry & Testing Services, Stockholm, Sweden.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    Identification of a group of brominated flame retardants as novel androgen receptor antagonists and potential neuronal and endocrine disrupters2015In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 74, p. 60-70Article in journal (Refereed)
    Abstract [en]

    Brominated flame-retardants (BFRs) are used in industrial products to reduce the risk of fire. However, their continuous release into the environment is a concern as they are often persistent, bioaccumulating and toxic. Information on the impact these compounds have on human health and wildlife is limited and only a few of them have been identified to disrupt hormone receptor functions. In the present study we used in silico modeling to determine the interactions of selected BFRs with the human androgen receptor (AR). Three compounds were found to dock into the ligand-binding domain of the human AR and these were further tested using in vitro analysis. Allyl 2,4,6-tribromophenyl ether (ATE), 2-bromoallyl 2,4,6-tribromophenyl ether (BATE) and 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE) were observed to act as AR antagonists. These BFRs have recently been detected in the environment, in house dust and in aquatic animals. The compounds have been detected at high concentrations in both blubber and brain of seals and we therefore also assessed their impact on the expression of L-type amino acid transporter system (LAT) genes, that are needed for amino acid uptake across the blood-brain barrier, as disruption of LAT gene function has been implicated in several brain disorders. The three BFRs down-regulated the expression of AR target genes that encode for prostate specific antigen (PSA), 5. α-reductases and β-microseminoprotein. The potency of PSA inhibition was of the same magnitude as the common prostate cancer drugs, demonstrating that these compounds are strong AR antagonists. Western blot analysis of AR protein showed that ATE, BATE and DPTE decreased the 5. α-dihydrotestosterone-induced AR protein levels, further confirming that these BFRs act as AR antagonists. The transcription of the LAT genes was altered by the three BFRs, indicating an effect on amino-acid uptake across cellular membranes and blood-brain barrier. This study demonstrated that ATE, BATE and DPTE are potent AR antagonists and the alterations in LAT gene transcription suggest that these compounds can affect neuronal functions and should be considered as potential neurotoxic and endocrine disrupting compounds.

  • 8.
    Basic, Vladimir T.
    et al.
    Department of Clinical Medicine, Örebro University, Örebro, Sweden.
    Jacobsen, Annette
    Department of Clinical Medicine, Örebro University, Örebro, Sweden; School of Biomedical Sciences, Charles Sturt University, WaggaWagga, Australia.
    Tadele, Elsa
    Department of Clinical Medicine, Örebro University, Örebro, Sweden; Medical University of Giessen, Molecular Biology and Medicine of the Lung program, Giessen, Germany.
    Banjop- Kharlyngdoh, Joubert
    Örebro University, School of Science and Technology.
    Sirsjö, Allan
    Department of Clinical Medicine, Örebro University, Örebro, Sweden.
    Abdel-Halim, Samy M.
    Division of Respiratory Medicine and Allergology, Department of Clinical Sciences, Danderyd Hospital, Stockholm, Sweden.
    Cigarette smoke exposure up-regulates Ubiquitin specific protease 19 in murine skeletal muscles as an adaptive response to prolonged ER stressManuscript (preprint) (Other academic)
    Abstract [en]

    Enhanced protein degradation via ubiquitin proteolytic system (UPS) was demonstrated to play an important role in the pathogenesis of cachexia syndrome and muscle wasting in patients with COPD and animal models of the disease. The role of cigarette smoke (CS) exposure in eliciting these abnormalities remains largely unknown. Usp19 is a member of UPS suggested to be involved in progressive muscle wasting in different catabolic conditions. However, factors regulating Usp19 expression, activity and correlation/s with CS-induced muscle atrophy remainunclear.

    Methods: To address these questions, 129 SvJ mice were exposed to cigarette smoke for 6 months and the gastrocnemius muscles were collected. Expression levels of Usp19 as well as pivotal mediators of ER stress response have been studied using PCR, qPCR, western blot and immunofluorescence. Factors regulating muscle Usp19 expression were studied using in-silico analysis of Usp19 promoter as well as by stimulating C2C12 myocytes with different inducers of ER stress including hypoxia, TNF and tunicamycin. Finally, Usp19 expression was depleted in C2C12 myocytes using specific Usp19 siRNA quadriplex and the expression of pivotal myogenic regulators were analyzed.

    Results: Usp19 mRNA expression was enhanced in skeletal muscles of CS-exposed mice. Concurrently, ER stress-associated Caspase 12 and Caspase 3 were activated in the CS-exposed group. Analysis of Usp19 promoter sequence revealed binding sites for ER stress response transcription factors such as HSF, STRE1 and AML1-α. Exposure of C2C12 myocytes to tunicamycin but not hypoxia elevated expression levels of Usp19. TNFstimulation elevated Usp19 protein expression but inhibited its RNA transcription in a dose- and time-dependent manner. Finally, Usp19 overexpression in tunicamycin-treated myocytes was accompanied by reduced expression of myosin heavy chain and tropomyosin and their levels were increased after knocking down Usp19 in C2C12 myocytes.

    Conclusions: In summary, our data demonstrated elevated expression of Usp19 in skeletal muscles of CS-exposed 129 SvJ mice. Moreover, Usp19 overexpression was associated with muscle adaptations to ER stress and suppression of myogenesis. Taken together; our results might provide further insight into molecular mechanisms underlying development and progression of skeletal muscle abnormalities in response to chronic cigarette smoke exposure.

  • 9.
    Carvalho, Raquel N.
    et al.
    Institute for Environment and Sustainability, European Commission-DG Joint Research Centre, Ispra, Italy.
    Arukwe, Augustine
    Norwegian University of Science & Technology, Trondheim, Norway.
    Ait-Aissa, Selim
    National Institute for Industrial Environment and Risks, Verneuil en Halatte, France.
    Bado-Nilles, Anne
    National Institute for Industrial Environment and Risks, Verneuil en Halatte, France; Reims University, Reims, France.
    Balzamo, Stefania
    Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Rome, Italy.
    Baun, Anders
    Department of Environmental Engineering,Technical University of Denmark, Kgs Lyngby, Denmark.
    Belkin, Shimshon
    Institute of Life Sciences, The Hebrew University, Jerusalem, Israel.
    Blaha, Ludek
    Faculty of Science, RECETOX, Masaryk University, Brno, Czech Republic.
    Brion, Francois
    National Institute for Industrial Environment and Risks, Verneuil en Halatte, France.
    Conti, Daniela
    Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Rome, Italy.
    Creusot, Nicolas
    National Institute for Industrial Environment and Risks, Verneuil en Halatte, France.
    Essig, Yona
    Analytical and Environmental Sciences Division, King's College, London, UK.
    Ferrero, Valentina E. V.
    European Commission-DG Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy.
    Flander-Putrle, Vesna
    Marine Biology Station Piran, National Institute of Biology, Ljubljana, Slovenia.
    Furhacker, Maria
    University of Natural Resources and Life Sciences, Vienna, Austria.
    Grillari-Voglauer, Regina
    University of Natural Resources and Life Sciences, Vienna, Austria.
    Hogstrand, Christer
    Diabetes and Nutritional Sciences Division, King's College London, London, UK.
    Jonas, Adam
    Faculty of Science, RECETOX, Masaryk University, Brno, Czech Republic.
    Kharlyngdoh, Joubert B.
    Örebro University, School of Science and Technology.
    Loos, Robert
    European Commission-DG Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy.
    Lundebye, Anne-Katrine
    National Institute of Nutrition and Seafood Research, Bergen, Norway.
    Modig, Carina
    Örebro University, School of Science and Technology. Life Science Center, Örebro University, Örebro, Sweden.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology. Life Science Center, Örebro University, Örebro, Sweden.
    Pillai, Smitha
    University of Natural Resources and Life Sciences, Vienna, Austria.
    Polak, Natasa
    Analytical and Environmental Sciences Division, King's College, London, UK.
    Potalivo, Monica
    Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Rome, Italy.
    Sanchez, Wilfried
    National Institute for Industrial Environment and Risks, Verneuil en Halatte, France.
    Schifferli, Andrea
    Swiss Centre for Applied Ecotoxicology, Eawag-EPFL, Dübendorf, Switzerland.
    Schirmer, Kristin
    Swiss Centre for Applied Ecotoxicology, Eawag-EPFL, Dübendorf, Switzerland.
    Sforzini, Susanna
    Department of Environmental and Life Sciences, Universita del Piemonte Orientale Vercelli Novara Alessandria, Alessandria, Italy.
    Sturzenbaum, Stephen R.
    Analytical and Environmental Sciences Division, King's College, London, UK.
    Søfteland, Liv
    National Institute of Nutrition and Seafood Research, Bergen, Norway.
    Turk, Valentina
    Marine Biology Station Piran, National Institute of Biology, Ljubljana, Slovenia.
    Viarengo, Aldo
    Department of Environmental and Life Sciences, Università del Piemonte Orientale Vercelli Novara Alessandria, Alessandria, Italy.
    Werner, Inge
    Swiss Centre for Applied Ecotoxicology, Swiss Federal Institute of Aquatic Science and Technology ( Eawag-EPFL), Dübendorf, Switzerland.
    Yagur-Kroll, Sharon
    Institute of Life Sciences, The Hebrew University, Jerusalem, Israel.
    Zounkova, Radka
    Faculty of Science, RECETOX, Masaryk University, Brno, Czech Republic.
    Lettieri, Teresa
    European Commission-DG Joint Research Centre, Institute for Environment and Sustainability, Rome, Italy.
    Mixtures of chemical pollutants at European legislation safety concentrations: how safe are they?2014In: Toxicological Sciences, ISSN 1096-6080, E-ISSN 1096-0929, Vol. 141, no 1, p. 218-233Article in journal (Refereed)
    Abstract [en]

    The risk posed by complex chemical mixtures in the environment to wildlife and humans is increasingly debated, but has been rarely tested under environmentally relevant scenarios. To address this issue, two mixtures of 14 or 19 substances of concern (pesticides, pharmaceuticals, heavy metals, polyaromatic hydrocarbons, a surfactant, and a plasticizer), each present at its safety limit concentration imposed by the European legislation, were prepared and tested for their toxic effects. The effects of the mixtures were assessed in 35 bioassays, based on 11 organisms representing different trophic levels. A consortium of 16 laboratories was involved in performing the bioassays. The mixtures elicited quantifiable toxic effects on some of the test systems employed, including i) changes in marine microbial composition, ii) microalgae toxicity, iii) immobilization in the crustacean Daphnia magna, iv) fish embryo toxicity, v) impaired frog embryo development, and vi) increased expression on oxidative stress-linked reporter genes. Estrogenic activity close to regulatory safety limit concentrations was uncovered by receptor-binding assays. The results highlight the need of precautionary actions on the assessment of chemical mixtures even in cases where individual toxicants are present at seemingly harmless concentrations.

  • 10.
    Kharlyngdoh, Joubert Banjop
    et al.
    Örebro University, School of Science and Technology.
    Asnake, Solomon
    Örebro University, School of Science and Technology.
    Pradhan, Ajay
    Örebro University, School of Science and Technology.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    TBECH, 1,2-dibromo-4-(1,2 dibromoethyl) cyclohexane, alters androgen receptor regulation in response to mutations associated with prostate cancer2016In: Toxicology and Applied Pharmacology, ISSN 0041-008X, E-ISSN 1096-0333, Vol. 307, p. 91-101Article in journal (Refereed)
    Abstract [en]

    Point mutations in the AR ligand-binding domain (LBD) can result in altered AR structures leading to changes of ligand specificity and functions. AR mutations associated to prostate cancer (PCa) have been shown to result in receptor activation by non-androgenic substances and anti-androgenic drugs. Two AR mutations known to alter the function of anti-androgens are the ART877A mutation, which is frequently detected mutation in PCa tumors and the ARW741C that is rare and has been derived in vitro following exposure of cells to the anti-androgen bicalutamide. AR activation by non-androgenic environmental substances has been suggested to affect PCa progression. In the present study we investigated the effect of AR mutations (ARW741C and ART877A) on the transcriptional activation following exposure of cells to an androgenic brominated flame retardant, 1,2-dibromo-4-(1,2 dibromoethyl) cyclohexane (TBECH, also named DBE-DBCH). The AR mutations resulted in higher interaction energies and increased transcriptional activation in response to TBECH diastereomer exposures. The ART877A mutation rendered AR highly responsive to low levels of DHT and TBECH and led to increased AR nuclear translocation. Gene expression analysis showed a stronger induction of AR target genes in LNCaP cells (ART877A) compared to T-47D cells (ARWT) following TBECH exposure. Furthermore, AR knockdown experiments confirmed the AR dependency of these responses. The higher sensitivity of ART877A and ARW741C to low levels of TBECH suggests that cells with these AR mutations are more susceptible to androgenic endocrine disrupters.

  • 11.
    Pradhan, Ajay
    et al.
    Örebro University, School of Science and Technology.
    Asnake, Solomon
    Örebro University, School of Science and Technology.
    Kharlyngdoh, Joubert Banjop
    Örebro University, School of Science and Technology.
    Modig, Carina
    Örebro University, School of Science and Technology.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    In silico and biological analysis of anti-androgen activity of the brominated flame retardants ATE, BATE and DPTE in zebrafishManuscript (preprint) (Other academic)
  • 12.
    Pradhan, Ajay
    et al.
    Örebro University, School of Science and Technology.
    Asnake, Solomon
    Örebro University, School of Science and Technology.
    Kharlyngdoh, Joubert Banjop
    Örebro University, School of Science and Technology.
    Modig, Carina
    Örebro University, School of Science and Technology.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    In silico and biological analysis of anti-androgen activity of the brominated flame retardants ATE, BATE and DPTE in zebrafish2015In: Chemico-Biological Interactions, ISSN 0009-2797, E-ISSN 1872-7786, Vol. 233, p. 35-45Article in journal (Refereed)
    Abstract [en]

    The brominated flame retardants (BFRs) 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH or DBE-DCBH) and allyl 2,4,6-tribromophenyl ether (ATE or TBP-AE) are alternative BFRs that have been introduced to replace banned BFRs. TBECH is a potential endocrine disrupter in human, chicken and zebrafish and in a recent study we showed that ATE, along with the structurally similar BFR 2,3-dibromopropyl 2,4,6-tribromophenyl ether (DPTE or TBP-DBPE) and its metabolite 2-bromoallyl 2,4,6-tribromophenyl ether (BATE or TBP-BAE) are potential endocrine and neuronal disrupters in human. In this study we analyzed ATE, BATE and DPTE for zebrafish androgen receptor (zAR) modulating properties. In silico analysis with two softwares, Molecular Operating Environment (MOE) and Internal Coordinate Mechanics (ICM), showed that ATE, BATE and DPTE bind to zAR. In vitro AR activation assay revealed that these three BFRs down-regulate 11-ketotestosterone (KT) mediated zAR activation. Exposure to 10 mu M DPTE resulted in reduced hatching success and like TBECH, BATE and DPTE at 10 mu M also had teratogenic properties with 20% and 50% back-bone curvature respectively. Gene transcription analysis in zebrafish embryos as well as in juveniles showed down-regulation of the androgen receptor and androgen response genes, which further support that these BFRs are androgen antagonists and potential endocrine disrupting compounds. Genes involved in steroidogenesis were also down-regulated by these BFRs. In view of this, the impact of these BFRs on humans and wildlife needs further analysis.

  • 13.
    Pradhan, Ajay
    et al.
    Örebro University, School of Science and Technology.
    Kharlyngdoh, Joubert Banjop
    Örebro University, School of Science and Technology.
    Asnake, Solomon
    Örebro University, School of Science and Technology.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    The brominated flame retardant TBECH activates the zebrafish (Danio rerio) androgen receptor, alters gene transcription and causes developmental disturbances2013In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 142, p. 63-72Article in journal (Refereed)
    Abstract [en]

    Tetrabromoethylcyclohexane (TBECH) is a brominated flame retardant that has been shown to be a potent agonist to the human androgen receptor (AR). However, while it is present in the environment, it is not known if it interacts with AR from aquatic species. The present study was therefore aimed at improving our understanding of how TBECH affects aquatic animals using zebrafish as a model organism. In silica modeling demonstrated that TBECH diastereomers bind to the zebrafish androgen receptor (zAR) and in vitro and in vivo data showed that TBECH has androgenic properties. Deleterious effects of TBECH were studied on embryonic and juvenile zebrafish and qRT-PCR analysis in vitro and in vivo was performed to determine TBECH effects on gene regulation. TBECH was found to delay hatching at 1 mu M and 10 mu M doses while morphological abnormalities and juvenile mortality was observed at 10 mu M. The qRT-PCR analysis showed alterations of multiple genes involved in chondrogenesis (cartilage development), metabolism and stress response. Thus, TBECH induces androgenic activity and has negative effects on zebrafish physiology and therefore its impact on the environment should be carefully monitored. (C) 2013 Elsevier B.V. All rights reserved.

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