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Leroy K, Pieters A, Cooreman A, Van Campenhout R, Cogliati B, Vinken M. Connexin-Based Channel Activity Is Not Specifically Altered by Hepatocarcinogenic Chemicals. Int J Mol Sci 2021; 22:11724. [PMID: 34769157 PMCID: PMC8584159 DOI: 10.3390/ijms222111724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/24/2021] [Accepted: 10/27/2021] [Indexed: 12/21/2022] Open
Abstract
Connexin-based channels play key roles in cellular communication and can be affected by deleterious chemicals. In this study, the effects of various genotoxic carcinogenic compounds, non-genotoxic carcinogenic compounds and non-carcinogenic compounds on the expression and functionality of connexin-based channels, both gap junctions and connexin hemichannels, were investigated in human hepatoma HepaRG cell cultures. Expression of connexin26, connexin32, and connexin43 was evaluated by means of real-time reverse transcription quantitative polymerase chain reaction analysis, immunoblot analysis and in situ immunostaining. Gap junction functionality was assessed via a scrape loading/dye transfer assay. Opening of connexin hemichannels was monitored by measuring extracellular release of adenosine triphosphate. It was found that both genotoxic and non-genotoxic carcinogenic compounds negatively affect connexin32 expression. However, no specific effects related to chemical type were observed at gap junction or connexin hemichannel functionality level.
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Affiliation(s)
- Kaat Leroy
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (A.C.); (R.V.C.)
| | - Alanah Pieters
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (A.C.); (R.V.C.)
| | - Axelle Cooreman
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (A.C.); (R.V.C.)
| | - Raf Van Campenhout
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (A.C.); (R.V.C.)
| | - Bruno Cogliati
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Av. Prof. Dr. Orlando Marques de Paiva 87, Cidade Universitária, São Paulo 05508-270, Brazil;
| | - Mathieu Vinken
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (A.C.); (R.V.C.)
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2
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Slováčková J, Slavík J, Kulich P, Večeřa J, Kováč O, Paculová H, Straková N, Fedr R, Silva JP, Carvalho F, Machala M, Procházková J. Polychlorinated environmental toxicants affect sphingolipid metabolism during neurogenesis in vitro. Toxicology 2021; 463:152986. [PMID: 34627992 DOI: 10.1016/j.tox.2021.152986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/17/2021] [Accepted: 10/05/2021] [Indexed: 10/20/2022]
Abstract
Sphingolipids (SLs) are important signaling molecules and functional components of cellular membranes. Although SLs are known as crucial regulators of neural cell physiology and differentiation, modulations of SLs by environmental neurotoxicants in neural cells and their neuronal progeny have not yet been explored. In this study, we used in vitro models of differentiated neuron-like cells, which were repeatedly exposed during differentiation to model environmental toxicants, and we analyzed changes in sphingolipidome, cellular morphology and gene expression related to SL metabolism or neuronal differentiation. We compared these data with the results obtained in undifferentiated neural cells with progenitor-like features. As model polychlorinated organic pollutants, we used 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3'-dichlorobiphenyl (PCB11) and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153). PCB153 revealed itself as the most prominent deregulator of SL metabolism and as potent toxicant during early phases of in vitro neurogenesis. TCDD exerted only minor changes in the levels of analysed lipid species, however, it significantly changed the rate of pro-neuronal differentiation and deregulated expression of neuronal markers during neurogenesis. PCB11 acted as a potent disruptor of in vitro neurogenesis, which induced significant alterations in SL metabolism and cellular morphology in both differentiated neuron-like models (differentiated NE4C and NG108-15 cells). We identified ceramide-1-phosphate, lactosylceramides and several glycosphingolipids to be the most sensitive SL species to exposure to polychlorinated pollutants. Additionally, we identified deregulation of several genes related to SL metabolism, which may be explored in future as potential markers of developmental neurotoxicity.
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Affiliation(s)
- Jana Slováčková
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 296/70, 62100, Brno, Czech Republic
| | - Josef Slavík
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 296/70, 62100, Brno, Czech Republic
| | - Pavel Kulich
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 296/70, 62100, Brno, Czech Republic
| | - Josef Večeřa
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 296/70, 62100, Brno, Czech Republic
| | - Ondrej Kováč
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 296/70, 62100, Brno, Czech Republic
| | - Hana Paculová
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 296/70, 62100, Brno, Czech Republic
| | - Nicol Straková
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 296/70, 62100, Brno, Czech Republic
| | - Radek Fedr
- Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265, Brno, Czech Republic
| | - João Pedro Silva
- Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Portugal
| | - Félix Carvalho
- Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Portugal
| | - Miroslav Machala
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 296/70, 62100, Brno, Czech Republic.
| | - Jiřina Procházková
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 296/70, 62100, Brno, Czech Republic; Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265, Brno, Czech Republic.
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3
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Brun NR, Panlilio JM, Zhang K, Zhao Y, Ivashkin E, Stegeman JJ, Goldstone JV. Developmental exposure to non-dioxin-like polychlorinated biphenyls promotes sensory deficits and disrupts dopaminergic and GABAergic signaling in zebrafish. Commun Biol 2021; 4:1129. [PMID: 34561524 PMCID: PMC8463681 DOI: 10.1038/s42003-021-02626-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 08/25/2021] [Indexed: 11/09/2022] Open
Abstract
The most abundant polychlorinated biphenyl (PCB) congeners found in the environment and in humans are neurotoxic. This is of particular concern for early life stages because the exposure of the more vulnerable developing nervous system to neurotoxic chemicals can result in neurobehavioral disorders. In this study, we uncover currently unknown links between PCB target mechanisms and neurobehavioral deficits using zebrafish as a vertebrate model. We investigated the effects of the abundant non-dioxin-like (NDL) congener PCB153 on neuronal morphology and synaptic transmission linked to the proper execution of a sensorimotor response. Zebrafish that were exposed during development to concentrations similar to those found in human cord blood and PCB contaminated sites showed a delay in startle response. Morphological and biochemical data demonstrate that even though PCB153-induced swelling of afferent sensory neurons, the disruption of dopaminergic and GABAergic signaling appears to contribute to PCB-induced motor deficits. A similar delay was observed for other NDL congeners but not for the potent dioxin-like congener PCB126. The effects on important and broadly conserved signaling mechanisms in vertebrates suggest that NDL PCBs may contribute to neurodevelopmental abnormalities in humans and increased selection pressures in vertebrate wildlife.
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Affiliation(s)
- Nadja R Brun
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
| | - Jennifer M Panlilio
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Kun Zhang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.,Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Yanbin Zhao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.,Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Evgeny Ivashkin
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA, USA.,A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia
| | - John J Stegeman
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
| | - Jared V Goldstone
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
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Applicability of Scrape Loading-Dye Transfer Assay for Non-Genotoxic Carcinogen Testing. Int J Mol Sci 2021; 22:ijms22168977. [PMID: 34445682 PMCID: PMC8396440 DOI: 10.3390/ijms22168977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/30/2021] [Accepted: 07/31/2021] [Indexed: 12/27/2022] Open
Abstract
Dysregulation of gap junction intercellular communication (GJIC) is recognized as one of the key hallmarks for identifying non-genotoxic carcinogens (NGTxC). Currently, there is a demand for in vitro assays addressing the gap junction hallmark, which would have the potential to eventually become an integral part of an integrated approach to the testing and assessment (IATA) of NGTxC. The scrape loading-dye transfer (SL-DT) technique is a simple assay for the functional evaluation of GJIC in various in vitro cultured mammalian cells and represents an interesting candidate assay. Out of the various techniques for evaluating GJIC, the SL-DT assay has been used frequently to assess the effects of various chemicals on GJIC in toxicological and tumor promotion research. In this review, we systematically searched the existing literature to gather papers assessing GJIC using the SL-DT assay in a rat liver epithelial cell line, WB-F344, after treating with chemicals, especially environmental and food toxicants, drugs, reproductive-, cardio- and neuro-toxicants and chemical tumor promoters. We discuss findings derived from the SL-DT assay with the known knowledge about the tumor-promoting activity and carcinogenicity of the assessed chemicals to evaluate the predictive capacity of the SL-DT assay in terms of its sensitivity, specificity and accuracy for identifying carcinogens. These data represent important information with respect to the applicability of the SL-DT assay for the testing of NGTxC within the IATA framework.
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Squecco R, Pierucci F, Idrizaj E, Frati A, Lenci E, Vicenti C, Iachini MC, Martinesi M, Garella R, Baccari MC, Francini F, Meacci E. Ceramide/protein phosphatase 2A axis is engaged in gap junction impairment elicited by PCB153 in liver stem-like progenitor cells. Mol Cell Biochem 2021; 476:3111-3126. [PMID: 33837873 PMCID: PMC8263450 DOI: 10.1007/s11010-021-04135-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 03/11/2021] [Indexed: 12/22/2022]
Abstract
The widespread environmental pollutant 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153) is a non-dioxin-like toxicant. It is a potential carcinogen compound able to induce gap junction (GJ) intercellular communication impairment, probably the first non-genomic event leading to tumor promotion. Although PCBs have been known for many years, the molecular mode of PCB153 action is still unclear. Recent studies from our research group have shown that the toxicant elicits a transient modulation of connexin (Cx) 43-formed GJs in hepatic stem-like WB-F344 cells involving sphingosine 1-phosphate (S1P) path. Taking into account that other strictly related bioactive sphingolipids, such as ceramide (Cer), may have different effects from S1P, here we aim to clarify the signaling paths engaged by PCB153 in the control of GJs, focusing primarily on the role of Cer. Accordingly, we have achieved a combined biomolecular and electrophysiological analysis of GJs in cultured WB-F344 cells treated with PCB153 at different time points. We have found that the toxicant elicited a time-dependent regulation of GJs formed by different Cx isoforms, through a transient modulation of Cer/Cer kinase (CerK) axis and, in turn, of protein phosphatase 2A (PP2A). Our new findings demonstrate the existence of a specific molecular mechanism downstream to Cer, which distinctly affects the voltage-dependent and -independent GJs in liver stem-like cells, and open new opportunities for the identification of additional potential targets of these environmental toxicants.
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Affiliation(s)
- Roberta Squecco
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Viale GB Morgagni 63, 50134, Florence, Italy
| | - Federica Pierucci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - Eglantina Idrizaj
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Viale GB Morgagni 63, 50134, Florence, Italy
| | - Alessia Frati
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - Elena Lenci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - Catia Vicenti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - Maria Chiara Iachini
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - Maria Martinesi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - Rachele Garella
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Viale GB Morgagni 63, 50134, Florence, Italy
| | - Maria Caterina Baccari
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Viale GB Morgagni 63, 50134, Florence, Italy
| | - Fabio Francini
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Viale GB Morgagni 63, 50134, Florence, Italy
| | - Elisabetta Meacci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy.
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6
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Bleak TC, Calaf GM. Breast and prostate glands affected by environmental substances (Review). Oncol Rep 2021; 45:20. [PMID: 33649835 PMCID: PMC7879422 DOI: 10.3892/or.2021.7971] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 01/08/2021] [Indexed: 12/17/2022] Open
Abstract
Environmental endocrine disruptor chemicals are substances that can alter the homeostasis of the endocrine system in living organisms. They can be released from several products used in daily activities. Once in the organism, they can disrupt the endocrine function by mimicking or blocking naturally occurring hormones due to their similar chemical structure. This endocrine disruption is the most important cause of the well‑known hormone‑associate types of cancer. Additionally, it is decisive to determine the susceptibility of each organ to these compounds. Therefore, the present review aimed to summarize the effect of different environmental substances such as bisphenol A, dichlorodiphenyltrichloroethane and polychlorinated biphenyls in both the mammary and the prostate tissues. These organs were chosen due to their association with the hormonal system and their common features in carcinogenic mechanisms. Outcomes derived from the present review may provide evidence that should be considered in future debates regarding the effects of endocrine disruptors on carcinogenesis.
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Affiliation(s)
- Tammy C. Bleak
- Instituto de Alta Investigación, Universidad de Tarapacá, Arica, Arica 1000000, Chile
| | - Gloria M. Calaf
- Instituto de Alta Investigación, Universidad de Tarapacá, Arica, Arica 1000000, Chile
- Center for Radiological Research, Columbia University Medical Center, New York, NY 10032, USA
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Gingrich J, Pu Y, Upham BL, Hulse M, Pearl S, Martin D, Avery A, Veiga-Lopez A. Bisphenol S enhances gap junction intercellular communication in ovarian theca cells. CHEMOSPHERE 2021; 263:128304. [PMID: 33155548 PMCID: PMC7726030 DOI: 10.1016/j.chemosphere.2020.128304] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 09/04/2020] [Accepted: 09/10/2020] [Indexed: 05/08/2023]
Abstract
Gap junction intercellular communication (GJIC) is necessary for ovarian function, and it is temporospatially regulated during follicular development and ovulation. At outermost layer of the antral follicle, theca cells provide structural, steroidogenic, and vascular support. Inter- and extra-thecal GJIC is required for intrafollicular trafficking of signaling molecules. Because GJIC can be altered by hormones and endocrine disrupting chemicals (EDCs), we tested if any of five common EDCs (bisphenol A (BPA), bisphenol S (BPS), bisphenol F (BPF), perfluorooctanesulfonic acid (PFOS), and triphenyltin chloride (TPT)) can interfere with theca cell GJIC. Since most chemicals are reported to repress GJIC, we hypothesized that all chemicals tested, within environmentally relevant human exposure concentrations, will inhibit theca cell GJICs. To evaluate this hypothesis, we used a scrape loading/dye transfer assay. BPS, but no other chemical tested, enhanced GJIC in a dose- and time-dependent manner in ovine primary theca cells. A signal-protein inhibitor approach was used to explore the GJIC-modulatory pathways involved. Phospholipase C and mitogen-activated protein kinase (MAPK) inhibitors significantly attenuated BPS-induced enhanced GJIC. Human theca cells were used to evaluate translational relevance of these findings. Human primary theca cells had a ∼40% increase in GJIC in response to BPS, which was attenuated with a MAPK inhibitor, suggestive of a conserved mechanism. Upregulation of GJIC could result in hyperplasia of the theca cell layer or prevent ovulation by holding the oocyte in meiotic arrest. Further studies are necessary to understand in vitro to in vivo translatability of these findings on follicle development and fertility outcomes.
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Affiliation(s)
- Jeremy Gingrich
- Department of Animal Science, Michigan State University, East Lansing, MI, 48824, USA; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Yong Pu
- Department of Animal Science, Michigan State University, East Lansing, MI, 48824, USA
| | - Brad L Upham
- Department of Pediatrics and Human Development, Michigan State University, East Lansing, MI, 48824, USA
| | - Madeline Hulse
- Department of Obstetrics and Gynecology, Sparrow Health System, Lansing, MI, 48912, USA
| | - Sarah Pearl
- Department of Obstetrics and Gynecology, Sparrow Health System, Lansing, MI, 48912, USA
| | - Denny Martin
- Department of Obstetrics and Gynecology, Sparrow Health System, Lansing, MI, 48912, USA
| | - Anita Avery
- Department of Obstetrics and Gynecology, Sparrow Health System, Lansing, MI, 48912, USA; Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Almudena Veiga-Lopez
- Department of Animal Science, Michigan State University, East Lansing, MI, 48824, USA; Department of Pathology, College of Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA.
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Mesnil M, Defamie N, Naus C, Sarrouilhe D. Brain Disorders and Chemical Pollutants: A Gap Junction Link? Biomolecules 2020; 11:biom11010051. [PMID: 33396565 PMCID: PMC7824109 DOI: 10.3390/biom11010051] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023] Open
Abstract
The incidence of brain pathologies has increased during last decades. Better diagnosis (autism spectrum disorders) and longer life expectancy (Parkinson's disease, Alzheimer's disease) partly explain this increase, while emerging data suggest pollutant exposures as a possible but still underestimated cause of major brain disorders. Taking into account that the brain parenchyma is rich in gap junctions and that most pollutants inhibit their function; brain disorders might be the consequence of gap-junctional alterations due to long-term exposures to pollutants. In this article, this hypothesis is addressed through three complementary aspects: (1) the gap-junctional organization and connexin expression in brain parenchyma and their function; (2) the effect of major pollutants (pesticides, bisphenol A, phthalates, heavy metals, airborne particles, etc.) on gap-junctional and connexin functions; (3) a description of the major brain disorders categorized as neurodevelopmental (autism spectrum disorders, attention deficit hyperactivity disorders, epilepsy), neurobehavioral (migraines, major depressive disorders), neurodegenerative (Parkinson's and Alzheimer's diseases) and cancers (glioma), in which both connexin dysfunction and pollutant involvement have been described. Based on these different aspects, the possible involvement of pollutant-inhibited gap junctions in brain disorders is discussed for prenatal and postnatal exposures.
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Affiliation(s)
- Marc Mesnil
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Norah Defamie
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Christian Naus
- Faculty of Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T1Z3, Canada;
| | - Denis Sarrouilhe
- Laboratoire de Physiologie Humaine, Faculté de Médecine et Pharmacie, 6 rue de La Milétrie, bât D1, TSA 51115, 86073 Poitiers, France
- Correspondence: ; Tel.: +33-5-49-45-43-58
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9
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Leroy K, Pieters A, Tabernilla A, Cooreman A, Van Campenhout R, Cogliati B, Vinken M. Targeting gap junctional intercellular communication by hepatocarcinogenic compounds. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2020; 23:255-275. [PMID: 32568623 DOI: 10.1080/10937404.2020.1781010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Gap junctions in liver, as in other organs, play a critical role in tissue homeostasis. Inherently, these cellular constituents are major targets for systemic toxicity and diseases, including cancer. This review provides an overview of chemicals that compromise liver gap junctions, in particular biological toxins, organic solvents, pesticides, pharmaceuticals, peroxides, metals and phthalates. The focus in this review is placed upon the mechanistic scenarios that underlie these adverse effects. Further, the potential use of gap junctional activity as an in vitro biomarker to identify non-genotoxic hepatocarcinogenic chemicals is discussed.
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Affiliation(s)
- Kaat Leroy
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Alanah Pieters
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Andrés Tabernilla
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Axelle Cooreman
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Raf Van Campenhout
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Bruno Cogliati
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Cidade Universitária , São Paulo, Brazil
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
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10
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Murati T, Miletić M, Pleadin J, Šimić B, Kmetič I. Cell membrane-related toxic responses and disruption of intercellular communication in PCB mechanisms of toxicity: A review. J Appl Toxicol 2020; 40:1592-1601. [PMID: 32648282 DOI: 10.1002/jat.4019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/13/2020] [Accepted: 05/15/2020] [Indexed: 02/06/2023]
Abstract
An understanding of polychlorinated biphenyl (PCB) congener-specific effects on cell membrane and intercellular communication is important within the studies of PCB absorption, organ-related PCB accumulation and exertion of toxic responses. Toxic potential of PCBs is linked to various deleterious effects on human health, including neurotoxicity, immunotoxicity, reproductive toxicity and genotoxicity and, recently in 2016 International Agency for Research on Cancer (IARC) has upgraded the classification of PCBs to Group 1 "Carcinogenic to humans." Proposed mechanisms of aforementioned PCBs adverse effects at cellular membrane level are: (i) downregulation of gap junction intercellular communication and/or connexins; (ii) compromised membrane integrity; and (iii) altered tight junction barrier function. This study, based on an extensive literature survey, shows the progress in scientific research of each of these three levels with the aim of pointing out the earliest toxic events of PCBs, which can result in serious cell/tissue/organ damage.
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Affiliation(s)
- Teuta Murati
- Laboratory for Toxicology, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia
| | - Marina Miletić
- Laboratory for Toxicology, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia
| | - Jelka Pleadin
- Laboratory for Analytical Chemistry, Department of Veterinary Public Health, Croatian Veterinary Institute, Zagreb, Croatia
| | - Branimir Šimić
- Laboratory for Toxicology, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia
| | - Ivana Kmetič
- Laboratory for Toxicology, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia
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11
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Pěnčíková K, Svržková L, Strapáčová S, Neča J, Bartoňková I, Dvořák Z, Hýžďalová M, Pivnička J, Pálková L, Lehmler HJ, Li X, Vondráček J, Machala M. In vitro profiling of toxic effects of prominent environmental lower-chlorinated PCB congeners linked with endocrine disruption and tumor promotion. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 237:473-486. [PMID: 29518658 PMCID: PMC5908724 DOI: 10.1016/j.envpol.2018.02.067] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/20/2018] [Accepted: 02/20/2018] [Indexed: 05/18/2023]
Abstract
The mechanisms contributing to toxic effects of airborne lower-chlorinated PCB congeners (LC-PCBs) remain poorly characterized. We evaluated in vitro toxicities of environmental LC-PCBs found in both indoor and outdoor air (PCB 4, 8, 11, 18, 28 and 31), and selected hydroxylated metabolites of PCB 8, 11 and 18, using reporter gene assays, as well as other functional cellular bioassays. We focused on processes linked with endocrine disruption, tumor promotion and/or regulation of transcription factors controlling metabolism of both endogenous compounds and xenobiotics. The tested LC-PCBs were found to be mostly efficient anti-androgenic (within nanomolar - micromolar range) and estrogenic (at micromolar concentrations) compounds, as well as inhibitors of gap junctional intercellular communication (GJIC) at micromolar concentrations. PCB 8, 28 and 31 were found to partially inhibit the aryl hydrocarbon receptor (AhR)-mediated activity. The tested LC-PCBs were also partial constitutive androstane receptor (CAR) and pregnane X receptor (PXR) agonists, with PCB 4, 8 and 18 being the most active compounds. They were inactive towards other nuclear receptors, such as vitamin D receptor, thyroid receptor α, glucocorticoid receptor or peroxisome proliferator-activated receptor γ. We found that only PCB 8 contributed to generation of oxidative stress, while all tested LC-PCBs induced arachidonic acid release (albeit without further modulations of arachidonic acid metabolism) in human lung epithelial cells. Importantly, estrogenic effects of hydroxylated (OH-PCB) metabolites of LC-PCBs (4-OH-PCB 8, 4-OH-PCB 11 and 4'-OH-PCB 18) were higher than those of the parent PCBs, while their other toxic effects were only slightly altered or suppressed. This suggested that metabolism may alter toxicity profiles of LC-PCBs in a receptor-specific manner. In summary, anti-androgenic and estrogenic activities, acute inhibition of GJIC and suppression of the AhR-mediated activity were found to be the most relevant modes of action of airborne LC-PCBs, although they partially affected also additional cellular targets.
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Affiliation(s)
- Kateřina Pěnčíková
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic
| | - Lucie Svržková
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic
| | - Simona Strapáčová
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic
| | - Jiří Neča
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic
| | - Iveta Bartoňková
- Department of Cell Biology and Genetics, Faculty of Science, Šlechtitelů 11, Palacký University, 78371 Olomouc, Czech Republic
| | - Zdeněk Dvořák
- Department of Cell Biology and Genetics, Faculty of Science, Šlechtitelů 11, Palacký University, 78371 Olomouc, Czech Republic
| | - Martina Hýžďalová
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic; Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czech Republic
| | - Jakub Pivnička
- Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czech Republic
| | - Lenka Pálková
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, 52242, IA, USA
| | - Xueshu Li
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, 52242, IA, USA
| | - Jan Vondráček
- Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czech Republic.
| | - Miroslav Machala
- Department of Chemistry and Toxicology, Veterinary Research Institute, Hudcova 70, 62100 Brno, Czech Republic.
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12
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Nyffeler J, Chovancova P, Dolde X, Holzer AK, Purvanov V, Kindinger I, Kerins A, Higton D, Silvester S, van Vugt-Lussenburg BMA, Glaab E, van der Burg B, Maclennan R, Legler DF, Leist M. A structure-activity relationship linking non-planar PCBs to functional deficits of neural crest cells: new roles for connexins. Arch Toxicol 2017; 92:1225-1247. [PMID: 29164306 DOI: 10.1007/s00204-017-2125-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 11/15/2017] [Indexed: 12/14/2022]
Abstract
Migration of neural crest cells (NCC) is a fundamental developmental process, and test methods to identify interfering toxicants have been developed. By examining cell function endpoints, as in the 'migration-inhibition of NCC (cMINC)' assay, a large number of toxicity mechanisms and protein targets can be covered. However, the key events that lead to the adverse effects of a given chemical or group of related compounds are hard to elucidate. To address this issue, we explored here, whether the establishment of two overlapping structure-activity relationships (SAR)-linking chemical structure on the one hand to a phenotypic test outcome, and on the other hand to a mechanistic endpoint-was useful as strategy to identify relevant toxicity mechanisms. For this purpose, we chose polychlorinated biphenyls (PCB) as a large group of related, but still toxicologically and physicochemically diverse structures. We obtained concentration-dependent data for 26 PCBs in the cMINC assay. Moreover, the test chemicals were evaluated by a new high-content imaging method for their effect on cellular re-distribution of connexin43 and for their capacity to inhibit gap junctions. Non-planar PCBs inhibited NCC migration. The potency (1-10 µM) correlated with the number of ortho-chlorine substituents; non-ortho-chloro (planar) PCBs were non-toxic. The toxicity to NCC partially correlated with gap junction inhibition, while it fully correlated (p < 0.0004) with connexin43 cellular re-distribution. Thus, our double-SAR strategy revealed a mechanistic step tightly linked to NCC toxicity of PCBs. Connexin43 patterns in NCC may be explored as a new endpoint relevant to developmental toxicity screening.
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Affiliation(s)
- Johanna Nyffeler
- In vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany.,Research Training Group RTG1331, 78457, Konstanz, Germany
| | - Petra Chovancova
- In vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRS-CB), 78457, Konstanz, Germany
| | - Xenia Dolde
- In vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRS-CB), 78457, Konstanz, Germany
| | - Anna-Katharina Holzer
- In vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany
| | - Vladimir Purvanov
- Biotechnology Institute Thurgau at the University of Konstanz, 8280, Kreuzlingen, Switzerland
| | - Ilona Kindinger
- Biotechnology Institute Thurgau at the University of Konstanz, 8280, Kreuzlingen, Switzerland
| | - Anna Kerins
- Cyprotex Discovery, No 24 Mereside, Alderley Park, Cheshire, SK10 4TG, UK
| | - David Higton
- Cyprotex Discovery, No 24 Mereside, Alderley Park, Cheshire, SK10 4TG, UK
| | - Steve Silvester
- Cyprotex Discovery, No 24 Mereside, Alderley Park, Cheshire, SK10 4TG, UK
| | | | - Enrico Glaab
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, 4362, Esch-sur-Alzette, Luxembourg
| | - Bart van der Burg
- BioDetection Systems bv, Science Park 406, 1098XH, Amsterdam, The Netherlands
| | - Richard Maclennan
- Cyprotex Discovery, No 24 Mereside, Alderley Park, Cheshire, SK10 4TG, UK
| | - Daniel F Legler
- Research Training Group RTG1331, 78457, Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRS-CB), 78457, Konstanz, Germany.,Biotechnology Institute Thurgau at the University of Konstanz, 8280, Kreuzlingen, Switzerland
| | - Marcel Leist
- In vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany. .,Research Training Group RTG1331, 78457, Konstanz, Germany. .,Konstanz Research School Chemical Biology (KoRS-CB), 78457, Konstanz, Germany.
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13
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Mutlu E, Gao L, Collins LB, Walker NJ, Hartwell HJ, Olson JR, Sun W, Gold A, Ball LM, Swenberg JA. Polychlorinated Biphenyls Induce Oxidative DNA Adducts in Female Sprague-Dawley Rats. Chem Res Toxicol 2016; 29:1335-1344. [PMID: 27436759 PMCID: PMC5020703 DOI: 10.1021/acs.chemrestox.6b00146] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Polychlorinated biphenyls (PCBs) are organic chemicals that were traditionally produced and widely used in industry as mixtures and are presently formed as byproducts of pigment and dye manufacturing. They are known to persist and bioaccumulate in the environment. Some have been shown to induce liver cancer in rodents. Although the mechanism of the toxicity of PCBs is unknown, it has been shown that they increase oxidative stress, including lipid peroxidation. We hypothesized that oxidative stress-induced DNA damage could be a contributor for PCB carcinogenesis and analyzed several DNA adducts in female Sprague-Dawley rats exposed to 3,3',4,4',5-pentachlorobiphenyl (PCB 126), 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153), and a binary mixture (PCB 126 + 153) for 14, 31, and 53 wks. Eight adducts were measured to profile oxidative DNA lesions, including 8-oxo-deoxyguanosine (8-oxo-dG), 1,N(6)-ethenodeoxyadenosine (1,N(6)-εdA), N(2),3-ethenoguanine (N(2),3-εG), 1,N(2)-ethenodeoxyguanosine (1,N(2)-εdG), as well as malondialdehyde (M1dG), acrolein (AcrdG), crotonaldehyde (CrdG), and 4-hydroxynonenal-derived dG adducts (HNEdG) by LC-MS/MS analysis. Statistically significant increases were observed for 8-oxo-dG and 1,N(6)-εdA concentrations in hepatic DNA of female rats exposed to the binary mixture (1000 ng/kg/day + 1000 μg/kg/day) but not in rats exposed to PCB 126 (1000 ng/kg/day) or PCB 153 (1000 μg/kg/day) for 14 and 31 wks. However, exposure to PCB 126 (1000 ng/kg/day) for 53 wks significantly increased 8-oxo-dG, 1,N(6)-εdA, AcrdG, and M1dG. Exposure to PCB 153 (1000 μg/kg/day) for 53 wks increased 8-oxo-dG, and 1,N(6)-εdA. Exposure to the binary mixture for 53 wks increased 8-oxo-dG, 1,N(6)-εdA, AcrdG, 1,N(2)-εdG, and N(2),3-εG significantly above control groups. Increased hepatic oxidative DNA adducts following exposure to PCB 126, PCB 153, or the binary mixture shows that an increase in DNA damage may play an important role in hepatic toxicity and carcinogenesis in female Sprague-Dawley rats.
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Affiliation(s)
- Esra Mutlu
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, United States
| | - Lina Gao
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Leonard B. Collins
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Nigel J. Walker
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, United States
| | - Hadley J. Hartwell
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - James R. Olson
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York 14214, United States
| | - Wei Sun
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Avram Gold
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Louise M. Ball
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - James A Swenberg
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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14
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Babica P, Zurabian R, Kumar ER, Chopra R, Mianecki MJ, Park JS, Jaša L, Trosko JE, Upham BL. Methoxychlor and Vinclozolin Induce Rapid Changes in Intercellular and Intracellular Signaling in Liver Progenitor Cells. Toxicol Sci 2016; 153:174-85. [PMID: 27413106 DOI: 10.1093/toxsci/kfw114] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Methoxychlor (MXC) and vinclozolin (VIN) are well-recognized endocrine disrupting chemicals known to alter epigenetic regulations and transgenerational inheritance; however, non-endocrine disruption endpoints are also important. Thus, we determined the effects of MXC and VIN on the dysregulation of gap junctional intercellular communication (GJIC) and activation of mitogen-activated protein kinases (MAPKs) in WB-F344 rat liver epithelial cells. Both chemicals induced a rapid dysregulation of GJIC at non-cytotoxic doses, with 30 min EC50 values for GJIC inhibition being 10 µM for MXC and 126 µM for VIN. MXC inhibited GJIC for at least 24 h, while VIN effects were transient and GJIC recovered after 4 h. VIN induced rapid hyperphosphorylation and internalization of gap junction protein connexin43, and both chemicals also activated MAPK ERK1/2 and p38. Effects on GJIC were not prevented by MEK1/2 inhibitor, but by an inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), resveratrol, and in the case of VIN, also, by a p38 inhibitor. Estrogen (ER) and androgen receptor (AR) modulators (estradiol, ICI 182,780, HPTE, testosterone, flutamide, VIN M2) did not attenuate MXC or VIN effects on GJIC. Our data also indicate that the effects were elicited by the parental compounds of MXC and VIN. Our study provides new evidence that MXC and VIN dysregulate GJIC via mechanisms involving rapid activation of PC-PLC occurring independently of ER- or AR-dependent genomic signaling. Such alterations of rapid intercellular and intracellular signaling events involved in regulations of gene expression, tissue development, function and homeostasis, could also contribute to transgenerational epigenetic effects of endocrine disruptors.
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Affiliation(s)
- Pavel Babica
- *Department of Experimental Phycology and Ecotoxicology, Institute of Botany, Brno 60200, Czech Republic; RECETOX, Faculty of Science, Masaryk University, Brno 62500, Czech Republic; Department of Pediatrics and Human Development, and Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824;
| | - Rimma Zurabian
- Department of Pediatrics and Human Development, and Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824; Department of Microbiology and Parasitology, Faculty of Medicine, National Autonomous University of Mexico, CdMx, 04510, Mexico
| | - Esha R Kumar
- Department of Pediatrics and Human Development, and Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824
| | - Rajus Chopra
- Department of Pediatrics and Human Development, and Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824
| | - Maxwell J Mianecki
- Department of Pediatrics and Human Development, and Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824
| | - Joon-Suk Park
- Department of Pediatrics and Human Development, and Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824; Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Korea
| | - Libor Jaša
- *Department of Experimental Phycology and Ecotoxicology, Institute of Botany, Brno 60200, Czech Republic; RECETOX, Faculty of Science, Masaryk University, Brno 62500, Czech Republic
| | - James E Trosko
- Department of Pediatrics and Human Development, and Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824
| | - Brad L Upham
- Department of Pediatrics and Human Development, and Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824
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15
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Steuer A, Schmidt A, Labohá P, Babica P, Kolb JF. Transient suppression of gap junctional intercellular communication after exposure to 100-nanosecond pulsed electric fields. Bioelectrochemistry 2016; 112:33-46. [PMID: 27439151 DOI: 10.1016/j.bioelechem.2016.07.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 07/07/2016] [Accepted: 07/08/2016] [Indexed: 12/18/2022]
Abstract
Gap junctional intercellular communication (GJIC) is an important mechanism that is involved and affected in many diseases and injuries. So far, the effect of nanosecond pulsed electric fields (nsPEFs) on the communication between cells was not investigated. An in vitro approach is presented with rat liver epithelial WB-F344 cells grown and exposed in a monolayer. In order to observe sub-lethal effects, cells were exposed to pulsed electric fields with a duration of 100ns and amplitudes between 10 and 20kV/cm. GJIC strongly decreased within 15min after treatment but recovered within 24h. Gene expression of Cx43 was significantly decreased and associated with a reduced total amount of Cx43 protein. In addition, MAP kinases p38 and Erk1/2, involved in Cx43 phosphorylation, were activated and Cx43 became hyperphosphorylated. Immunofluorescent staining of Cx43 displayed the disassembly of gap junctions. Further, a reorganization of the actin cytoskeleton was observed whereas tight junction protein ZO-1 was not significantly affected. All effects were field- and time-dependent and most pronounced within 30 to 60min after treatment. A better understanding of a possible manipulation of GJIC by nsPEFs might eventually offer a possibility to develop and improve treatments.
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Affiliation(s)
- Anna Steuer
- Leibniz Institute for Plasma Science and Technology, Greifswald, Germany
| | - Anke Schmidt
- Leibniz Institute for Plasma Science and Technology, Greifswald, Germany
| | - Petra Labohá
- Leibniz Institute for Plasma Science and Technology, Greifswald, Germany; Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Pavel Babica
- Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Juergen F Kolb
- Leibniz Institute for Plasma Science and Technology, Greifswald, Germany.
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16
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Chubb LS, Andersen ME, Broccardo CJ, Legare ME, Billings RE, Dean CE, Hanneman WH. Regional Induction of CYP1A1 in Rat Liver Following Treatment with Mixtures of PCB 126 and PCB 153. Toxicol Pathol 2016; 32:467-73. [PMID: 15223772 DOI: 10.1080/01926230490483306] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Liver enzyme induction has been shown previously to be regional with clear borders between induced and uninduced regions in vivo, and cells either fully induced or not induced in vitro. The current study examined this phenomenon in vivo by evaluating enzyme induction after exposure to PCB 126 and PCB 153 in female Fisher 344 (F344) and male Sprague—Dawley (SD) rats. IHC revealed a regional induction of CYP1A1 after exposure to PCB 126, apparent in the centrilobular region at lower doses and progressing to panlobular with higher doses. PCB 153 exposure induced CYP2B1/2 in the centrilobular region, which spread to the midzonal region as the dose increased, but never became panlobular even at the highest dosage tested. In rats treated with PCB 126 in combination with high doses of PCB 153, induction of CYP1A1 occurred preferentially in the periportal region, a reversal from the pattern seen with PCB 126 alone. This CYP1A1 induction pattern reversal is a unique example of complex biological interactions between coplanar (PCB 126) and noncoplanar (PCB 153) halogenated aromatic hydrocarbons.
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Affiliation(s)
- Laura S Chubb
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523-1680, USA
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17
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Pierucci F, Frati A, Squecco R, Lenci E, Vicenti C, Slavik J, Francini F, Machala M, Meacci E. Non-dioxin-like organic toxicant PCB153 modulates sphingolipid metabolism in liver progenitor cells: its role in Cx43-formed gap junction impairment. Arch Toxicol 2016; 91:749-760. [PMID: 27318803 DOI: 10.1007/s00204-016-1750-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 06/08/2016] [Indexed: 12/13/2022]
Abstract
The non-dioxin-like environmental toxicant 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153), member of a group of persistent organic pollutants wide-spread throughout the environment, reduces gap junction intercellular communication (GJIC), an event possibly associated with tumor promotion. Since very few studies have investigated the signaling effectors and mode(s) of action of PCB153, and it is known that the gap junction (GJ) protein Cx43 can be regulated by the bioactive sphingolipid (SL) sphingosine 1-phosphate (S1P), this in vitro study mainly addresses whether SL metabolism is affected by PCB153 in rat liver epithelial WB-F344 cells. PCB153 treatment obtained significant changes in the S1P/ceramide (Cer) ratio, known to be crucial in determining cell fate. In particular, an increase in S1P at 30 min and a decrease of the bioactive lipid at 3 h were observed, whereas Cer level increased at 1 h and 24 h. Notably, a time-dependent modulation of sphingosine kinase (SphK), the enzyme responsible for S1P synthesis, and of its regulators, ERK1/2 and protein phosphatase PP2A, supports the involvement of these signaling effectors in PCB153 toxicity. Electrophysiological analyses, furthermore, indicated that the lipophilic environmental toxicant significantly reduced GJ biophysical properties, affecting both voltage-dependent (such as those formed by Cx43 and/or Cx32) and voltage-independent channels, thereby demonstrating that PCB153 may act differently on GJs formed by distinct Cx isoforms. SphK down-regulation alone induced GJIC impairment, and, when combined with PCB153, the acute effect on GJ suppression was additive. Moreover, after enzyme-specific gene silencing, the SphK1 isoform appears to be responsible for down-regulating Cx43 expression, while being the target of PCB153 at short-term exposure. In conclusion, we provide the first evidence of novel effectors in PCB153 toxic action in rat liver stem-like cells, leading us to consider SLs as potential markers for preventing GJIC deregulation and, thus, the tumorigenic action elicited by this environmental toxicant.
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Affiliation(s)
- F Pierucci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research Unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - A Frati
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research Unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - R Squecco
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Viale GB Morgagni 63, 50134, Florence, Italy
| | - E Lenci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research Unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - C Vicenti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research Unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - J Slavik
- Veterinary Research Institute, Hudcova 70, 62100, Brno, Czech Republic
| | - F Francini
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Viale GB Morgagni 63, 50134, Florence, Italy
| | - M Machala
- Veterinary Research Institute, Hudcova 70, 62100, Brno, Czech Republic
| | - E Meacci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research Unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy.
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18
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Nahta R, Al-Mulla F, Al-Temaimi R, Amedei A, Andrade-Vieira R, Bay SN, Brown DG, Calaf GM, Castellino RC, Cohen-Solal KA, Colacci A, Cruickshanks N, Dent P, Di Fiore R, Forte S, Goldberg GS, Hamid RA, Krishnan H, Laird DW, Lasfar A, Marignani PA, Memeo L, Mondello C, Naus CC, Ponce-Cusi R, Raju J, Roy D, Roy R, Ryan EP, Salem HK, Scovassi AI, Singh N, Vaccari M, Vento R, Vondráček J, Wade M, Woodrick J, Bisson WH. Mechanisms of environmental chemicals that enable the cancer hallmark of evasion of growth suppression. Carcinogenesis 2015; 36 Suppl 1:S2-18. [PMID: 26106139 DOI: 10.1093/carcin/bgv028] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
As part of the Halifax Project, this review brings attention to the potential effects of environmental chemicals on important molecular and cellular regulators of the cancer hallmark of evading growth suppression. Specifically, we review the mechanisms by which cancer cells escape the growth-inhibitory signals of p53, retinoblastoma protein, transforming growth factor-beta, gap junctions and contact inhibition. We discuss the effects of selected environmental chemicals on these mechanisms of growth inhibition and cross-reference the effects of these chemicals in other classical cancer hallmarks.
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Affiliation(s)
- Rita Nahta
- Departments of Pharmacology and Hematology & Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, GA 30322, USA, Department of Pathology, Kuwait University, Safat 13110, Kuwait, Department of Experimental and Clinical Medicine, University of Firenze, 50134 Florence, Italy, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada, Program in Genetics and Molecular Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30322, USA, Department of Environmental and Radiological Health Sciences/Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA, Center for Radiological Research, Columbia University Medical Center, New York, NY 10032, USA, Instituto de Alta Investigacion, Universidad de Tarapaca, Arica 8097877, Chile, Division of Hematology and Oncology, Department of Pediatrics, Children's Healthcare of Atlanta and Emory University, Atlanta, GA 30322, USA, Department of Medicine/Medical Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ 08901-1914, USA, Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy, Departments of Neurosurgery and Biochemistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 980033, USA, Department of Biological, Chemical, and Pharmaceutical Sciences and Technologies, Polyclinic Plexus, University of Palermo, 90127 Palermo, Italy, Mediterranean Institute of Oncology, 95029 Viagrande, Italy, Graduate School of Biomedical Sciences and Department of Molecular Biology, School of Osteopathic Medicine, Rowan University, Stratford, NJ 08084-1501, USA, Department of Biomedical Science, Faculty of Medicine and Health Sciences, University Putra, Serdang, Selangor 43400, Malaysia, Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontari
| | - Fahd Al-Mulla
- Department of Pathology, Kuwait University, Safat 13110, Kuwait
| | | | - Amedeo Amedei
- Department of Experimental and Clinical Medicine, University of Firenze, 50134 Florence, Italy
| | - Rafaela Andrade-Vieira
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Sarah N Bay
- Program in Genetics and Molecular Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30322, USA
| | - Dustin G Brown
- Department of Environmental and Radiological Health Sciences/Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA
| | - Gloria M Calaf
- Center for Radiological Research, Columbia University Medical Center, New York, NY 10032, USA, Instituto de Alta Investigacion, Universidad de Tarapaca, Arica 8097877, Chile
| | - Robert C Castellino
- Division of Hematology and Oncology, Department of Pediatrics, Children's Healthcare of Atlanta and Emory University, Atlanta, GA 30322, USA
| | - Karine A Cohen-Solal
- Department of Medicine/Medical Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ 08901-1914, USA
| | - Annamaria Colacci
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy
| | - Nichola Cruickshanks
- Departments of Neurosurgery and Biochemistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 980033, USA
| | - Paul Dent
- Departments of Neurosurgery and Biochemistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 980033, USA
| | - Riccardo Di Fiore
- Department of Biological, Chemical, and Pharmaceutical Sciences and Technologies, Polyclinic Plexus, University of Palermo, 90127 Palermo, Italy
| | - Stefano Forte
- Mediterranean Institute of Oncology, 95029 Viagrande, Italy
| | - Gary S Goldberg
- Graduate School of Biomedical Sciences and Department of Molecular Biology, School of Osteopathic Medicine, Rowan University, Stratford, NJ 08084-1501, USA
| | - Roslida A Hamid
- Department of Biomedical Science, Faculty of Medicine and Health Sciences, University Putra, Serdang, Selangor 43400, Malaysia
| | - Harini Krishnan
- Graduate School of Biomedical Sciences and Department of Molecular Biology, School of Osteopathic Medicine, Rowan University, Stratford, NJ 08084-1501, USA
| | - Dale W Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Ahmed Lasfar
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers, the State University of New Jersey, Piscataway, NJ 60503, USA
| | - Paola A Marignani
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Lorenzo Memeo
- Mediterranean Institute of Oncology, 95029 Viagrande, Italy
| | - Chiara Mondello
- Institute of Molecular Genetics, National Research Council, 27100 Pavia, Italy
| | - Christian C Naus
- Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Richard Ponce-Cusi
- Instituto de Alta Investigacion, Universidad de Tarapaca, Arica 8097877, Chile
| | - Jayadev Raju
- Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario K1A0K9, Canada
| | - Debasish Roy
- Department of Natural Science, The City University of New York at Hostos Campus, Bronx, NY 10451, USA
| | - Rabindra Roy
- Molecular Oncology Program, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC 20057, USA
| | - Elizabeth P Ryan
- Department of Environmental and Radiological Health Sciences/Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA
| | - Hosni K Salem
- Urology Dept., kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo 12515, Egypt
| | - A Ivana Scovassi
- Institute of Molecular Genetics, National Research Council, 27100 Pavia, Italy
| | - Neetu Singh
- Advanced Molecular Science Research Centre, King George's Medical University, Lucknow, UP 226003, India
| | - Monica Vaccari
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy
| | - Renza Vento
- Department of Biological, Chemical, and Pharmaceutical Sciences and Technologies, Polyclinic Plexus, University of Palermo, 90127 Palermo, Italy, Sbarro Institute for Cancer Research and Molecular Medicine, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA
| | - Jan Vondráček
- Department of Cytokinetics, Institute of Biophysics AS CR, Brno 612 65, Czech Republic
| | - Mark Wade
- Center for Genomic Science of IIT@SEMM, Istituto Italiano di Tecnologia (IIT), Milan 16163, Italy and
| | - Jordan Woodrick
- Molecular Oncology Program, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC 20057, USA
| | - William H Bisson
- Environmental and Molecular Toxicology, Environmental Health Sciences Center, Oregon State University, Corvallis, OR 97331, USA
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Sovadinova I, Babica P, Böke H, Kumar E, Wilke A, Park JS, Trosko JE, Upham BL. Phosphatidylcholine Specific PLC-Induced Dysregulation of Gap Junctions, a Robust Cellular Response to Environmental Toxicants, and Prevention by Resveratrol in a Rat Liver Cell Model. PLoS One 2015; 10:e0124454. [PMID: 26023933 PMCID: PMC4449167 DOI: 10.1371/journal.pone.0124454] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 03/10/2015] [Indexed: 12/04/2022] Open
Abstract
Dysregulation of gap junctional intercellular communication (GJIC) has been associated with different pathologies, including cancer; however, molecular mechanisms regulating GJIC are not fully understood. Mitogen Activated Protein Kinase (MAPK)-dependent mechanisms of GJIC-dysregulation have been well-established, however recent discoveries have implicated phosphatidylcholine-specific phospholipase C (PC-PLC) in the regulation of GJIC. What is not known is how prevalent these two signaling mechanisms are in toxicant/toxin-induced dysregulation of GJIC, and do toxicants/toxins work through either signaling mechanisms or both, or through alternative signaling mechanisms. Different chemical toxicants were used to assess whether they dysregulate GJIC via MEK or PC-PLC, or both Mek and PC-PLC, or through other signaling pathways, using a pluripotent rat liver epithelial oval-cell line, WB-F344. Epidermal growth factor, 12-O-tetradecanoylphorbol-13-acetate, thrombin receptor activating peptide-6 and lindane regulated GJIC through a MEK1/2-dependent mechanism that was independent of PC-PLC; whereas PAHs, DDT, PCB 153, dicumylperoxide and perfluorodecanoic acid inhibited GJIC through PC-PLC independent of Mek. Dysregulation of GJIC by perfluorooctanoic acid and R59022 required both MEK1/2 and PC-PLC; while benzoylperoxide, arachidonic acid, 18β-glycyrrhetinic acid, perfluorooctane sulfonic acid, 1-monolaurin, pentachlorophenol and alachlor required neither MEK1/2 nor PC-PLC. Resveratrol prevented dysregulation of GJIC by toxicants that acted either through MEK1/2 or PC-PLC. Except for alachlor, resveratrol did not prevent dysregulation of GJIC by toxicants that worked through PC-PLC-independent and MEK1/2-independent pathways, which indicated at least two other, yet unidentified, pathways that are involved in the regulation of GJIC. In conclusion: the dysregulation of GJIC is a contributing factor to the cancer process; however the underlying mechanisms by which gap junction channels are closed by toxicants vary. Thus, accurate assessments of risk posed by toxic agents, and the role of dietary phytochemicals play in preventing or reversing the effects of these agents must take into account the specific mechanisms involved in the cancer process.
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Affiliation(s)
- Iva Sovadinova
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Research Centre for Toxic Compounds in the Environment—RECETOX, Masaryk University, Kamenice 5, CZ62500, Brno, Czech Republic
| | - Pavel Babica
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Department of Experimental Phycology and Ecotoxicology, Institute of Botany ASCR, Lidicka 25/27, CZ60200, Brno, Czech Republic
| | - Hatice Böke
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Esha Kumar
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Andrew Wilke
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Joon-Suk Park
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Korea
| | - James E. Trosko
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Brad L. Upham
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- * E-mail:
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20
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Nováková K, Kohoutek J, Adamovský O, Brack W, Krauss M, Bláha L. Novel metabolites in cyanobacterium Cylindrospermopsis raciborskii with potencies to inhibit gap junctional intercellular communication. JOURNAL OF HAZARDOUS MATERIALS 2013; 262:571-579. [PMID: 24095997 DOI: 10.1016/j.jhazmat.2013.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/21/2013] [Accepted: 09/05/2013] [Indexed: 06/02/2023]
Abstract
Despite intensive research into toxic bloom-forming cyanobacteria, the majority of their metabolites remain unknown. The present study explored in detail a novel bioactivity identified in cyanobacteria, i.e. inhibition of gap junctional intercellular communication (GJIC), a marker of tumor promotion. The extracellular mixture (exudate) of the cyanobacterial strain Cylindrospermopsis raciborskii (SAG 1.97) was fractionated by semi-preparative reversed phase HPLC, and the fractions assessed for their potencies to inhibit GJIC. Two non-polar fractions that significantly inhibited GJIC were further fractionated, tested and analyzed using multiple mass spectrometric methods. Investigations led to the identification of a putative chemical compound (molecular formula C18H34O3, m/z 299.2581 for the [M+H](+) ion) responsible for observed bioactivities. Specific inhibitors of signaling pathways were used to screen for biochemical mechanisms beyond GJIC inhibition, and the results indicate the involvement of ERK1/2 kinases via a mechanism related to the action of epidermal growth factor EGF but clearly distinct from other anthropogenic tumor promoters like polychlorinated biphenyls or polycyclic aromatic hydrocarbons. The chemical and in vitro toxicological characterizations of the newly described metabolite provide important insights into the still poorly understood health impacts of complex toxic cyanobacterial blooms and indicate that currently applied monitoring practices may underestimate actual risks.
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Affiliation(s)
- K Nováková
- Masaryk University, Faculty of Science, RECETOX, Kamenice 753/5, 62500 Brno, Czech Republic
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21
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Andrysík Z, Procházková J, Kabátková M, Umannová L, Šimečková P, Kohoutek J, Kozubík A, Machala M, Vondráček J. Aryl hydrocarbon receptor-mediated disruption of contact inhibition is associated with connexin43 downregulation and inhibition of gap junctional intercellular communication. Arch Toxicol 2012; 87:491-503. [DOI: 10.1007/s00204-012-0963-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 10/11/2012] [Indexed: 11/29/2022]
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22
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Nováková K, Bláha L, Babica P. Tumor promoting effects of cyanobacterial extracts are potentiated by anthropogenic contaminants--evidence from in vitro study. CHEMOSPHERE 2012; 89:30-37. [PMID: 22572165 DOI: 10.1016/j.chemosphere.2012.04.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 03/22/2012] [Accepted: 04/04/2012] [Indexed: 05/31/2023]
Abstract
Inhibition of gap junctional intercellular communication (GJIC) is affiliated with tumor promotion process and it has been employed as an in vitro biomarker for evaluation of tumor promoting effects of chemicals. In the present study we investigated combined effects of anthropogenic environmental contaminants 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) and fluoranthene, cyanotoxins microcystin-LR and cylindrospermopsin, and extracts of laboratory cultures of cyanobacteria Aphanizomenon gracile and Cylindrospermopsis raciborskii, on GJIC in the rat liver epithelial cell line WB-F344. Binary mixtures of PCB 153 with fluoranthene and the mixtures of the two cyanobacterial strains elicited simple additive effects on GJIC after 30 min exposure, whereas microcystin-LR and cylindrospermopsin neither inhibited GJIC nor altered effects of PCB 153 or fluoranthene. However, synergistic effects were observed in the cells exposed to binary mixtures of anthropogenic contaminants (PCB 153 or fluoranthene) and cyanobacterial extracts. The synergistic effects were especially pronounced after prolonged (6-24h) co-exposure to fluoranthene and A. gracile extract, when mixture caused nearly complete GJIC inhibition, while none of the individual components caused any downregulation of GJIC at the same concentration and exposure time. The effects of cyanobacterial extracts were independent of microcystin-LR or cylindrospermopsin, which were not detected in cyanobacterial biomass. It provides further evidence on the presence of unknown tumor promoting metabolites in cyanobacteria. Clear potentiation of the GJIC inhibition observed in the mixtures of two anthropogenic contaminants and cyanobacteria highlight the importance of combined toxic effects of chemicals in complex environmental mixtures.
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Affiliation(s)
- Kateřina Nováková
- Research Centre for Toxic Compounds in the Environment, RECETOX, Faculty of Science, Masaryk University, Kamenice 3, Brno CZ62500, Czech Republic.
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23
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Piccoli C, D'Aprile A, Scrima R, Ambrosi L, Zefferino R, Capitanio N. Subcytotoxic mercury chloride inhibits gap junction intercellular communication by a redox- and phosphorylation-mediated mechanism. Free Radic Biol Med 2012; 52:916-27. [PMID: 22240155 DOI: 10.1016/j.freeradbiomed.2011.12.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 12/09/2011] [Accepted: 12/20/2011] [Indexed: 11/26/2022]
Abstract
Gap junctions play a central role in coordinating intercellular signal-transduction pathways to control tissue homeostasis. Deregulation of gap junctional intercellular communication is a common phenotype of cancer cells and supports its involvement in the carcinogenesis process. Many carcinogens, like environmental heavy-metal chemical pollutants, are known to activate various signal transduction mechanisms and modulate GJIC. They act as tumor promoters on preexisting "initiated" cells, rather than as genotoxic initiators, albeit their mode of action is often unknown. In this study we investigated the effect of Hg(II) (HgCl(2)) on GJIC in cultured human keratinocytes. It is shown that subcytotoxic concentrations of HgCl(2) as low as 10 nM cause inhibition of the GJIC, assessed by dye transfer assay, despite enhanced expression of connexins. In addition, HgCl(2)-treated keratinocytes exhibited a decrease of free thiols and accumulation of mitochondria-derived reactive oxygen species, albeit no effect on the respiratory chain activity was observed. Treatment of HgCl(2)-exposed keratinocytes with the PKC inhibitor calphostin C and with all-trans retinoic acid resulted in rescue of the mitochondrial ROS overproduction and full recovery of the GJIC. Similar results were obtained with the PKA activator db-cAMP. Overall, the presented results support a cross-talk between the altered intracellular redox tone and PKA- and PKC-mediated signaling in HgCl(2)-challenged keratinocytes. These events, although not cytotoxic, lead to inhibition of GJIC and possibly to carcinogenic priming.
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Affiliation(s)
- Claudia Piccoli
- Department of Biomedical Sciences, University of Foggia, Foggia, Italy
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Bytingsvik J, Lie E, Aars J, Derocher AE, Wiig Ø, Jenssen BM. PCBs and OH-PCBs in polar bear mother-cub pairs: a comparative study based on plasma levels in 1998 and 2008. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 417-418:117-128. [PMID: 22264925 DOI: 10.1016/j.scitotenv.2011.12.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 12/14/2011] [Accepted: 12/15/2011] [Indexed: 05/31/2023]
Abstract
The aim of this study was to examine the plasma concentrations and prevalence of polychlorinated biphenyls (PCBs) and hydroxylated PCB-metabolites (OH-PCBs) in polar bear (Ursus maritimus) mothers (n=26) and their 4 months old cubs-of-the-year (n=38) from Svalbard to gain insight into the mother-cub transfer, biotransformation and to evaluate the health risk associated with the exposure to these contaminants. As samplings were performed in 1997/1998 and 2008, we further investigated the differences in levels and pattern of PCBs between the two sampling years. The plasma concentrations of Σ(21)PCBs (1997/1998: 5710 ± 3090 ng/g lipid weight [lw], 2008: 2560 ± 1500 ng/g lw) and Σ(6)OH-PCBs (1997/1998: 228 ± 60 ng/g wet weight [ww], 2008: 80 ± 38 ng/g ww) in mothers were significantly lower in 2008 compared to in 1997/1998. In cubs, the plasma concentrations of Σ(21)PCBs (1997/1998: 14680 ± 5350 ng/g lw, 2008: 6070 ± 2590 ng/g lw) and Σ(6)OH-PCBs (1997/1998: 98 ± 23 ng/g ww, 2008: 49 ± 21 ng/g ww) were also significantly lower in 2008 than in 1997/1998. Σ(21)PCBs in cubs was 2.7 ± 0.7 times higher than in their mothers. This is due to a significant maternal transfer of these contaminants. In contrast, Σ(6)OH-PCBs in cubs were approximately 0.53 ± 0.16 times the concentration in their mothers. This indicates a lower maternal transfer of OH-PCBs compared to PCBs. The majority of the metabolite/precursor-ratios were lower in cubs compared to mothers. This may indicate that cubs have a lower endogenous capacity to biotransform PCBs to OH-PCBs than polar bear mothers. Exposure to PCBs and OH-PCBs is a potential health risk for polar bears, and the levels of PCBs and OH-PCBs in cubs from 2008 were still above levels associated with health effects in humans and wildlife.
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Affiliation(s)
- Jenny Bytingsvik
- Norwegian University of Science and Technology (NTNU), Department of Biology, Høgskoleringen 5, NO-7491 Trondheim, Norway.
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25
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Pavlíková N, Bláhová L, Klán P, Bathula SR, Sklenář V, Giesy JP, Bláha L. Enantioselective effects of alpha-hexachlorocyclohexane (HCH) isomers on androgen receptor activity in vitro. CHEMOSPHERE 2012; 86:65-69. [PMID: 21962538 DOI: 10.1016/j.chemosphere.2011.08.052] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 08/24/2011] [Indexed: 05/31/2023]
Abstract
Alpha-hexachlorocyclohexane (alpha-HCH), a part of the HCH pesticide mixture, is one of the most widespread persistent organic pollutants. Interestingly, only limited number of studies addressed the toxicity of alpha-HCH and the effects of its individual optical isomers have not been investigated in detail. In the present study we separated two alpha-HCH enantiomers by preparative HPLC and studied their activities towards androgen receptor (AR) using the MDA-kb2 cell line stably transfected with the luciferase reporter gene under the control of AR. There was no direct effect of alpha-HCH on AR but both isomers significantly suppressed the activity of AR in co-exposure with the natural ligand dihydrotestosterone in a concentration-dependent manner. One of the enantiomers appeared to be more active at lower concentration, which was also supported by the molecular modeling calculations with AR that showed a slight difference in estimated free energy of binding and inhibition constant between two enantiomers. Although studies with other pesticides demonstrated strong enantioselective differences in toxicity, the present research shows rather minor differences in modulations of AR by both alpha-HCH enantiomers. For the first time, enantioselective effects of alpha-HCH were demonstrated and the results suggest interaction with multiple regulatory events controlling the AR activity. Full elucidation of the toxicity mechanism will require further research.
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Affiliation(s)
- Nela Pavlíková
- Research Centre for Toxic Compounds in the Environment, Masaryk University, Kamenice 3, CZ625 00 Brno, Czech Republic
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26
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Stenberg M, Hamers T, Machala M, Fonnum F, Stenius U, Lauy AA, van Duursen MBM, Westerink RHS, Fernandes ECA, Andersson PL. Multivariate toxicity profiles and QSAR modeling of non-dioxin-like PCBs--an investigation of in vitro screening data from ultra-pure congeners. CHEMOSPHERE 2011; 85:1423-1429. [PMID: 21890175 DOI: 10.1016/j.chemosphere.2011.08.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 08/04/2011] [Accepted: 08/04/2011] [Indexed: 05/31/2023]
Abstract
The non-dioxin-like PCBs (NDL-PCBs) found in food and human samples have a complex spectrum of adverse effects, but lack a detailed risk assessment. The toxicity profiles of 21 carefully selected PCBs (19 NDL-PCBs) were identified by in vitro screening in 17 different assays on specific endpoints related to neurotoxicity, endocrine disruption and tumor promotion. To ensure that the test results were not affected by polychlorinated dioxins, dibenzofurans or DL-PCB contaminants, the NDL-PCB congeners were thoroughly purified before testing. Principal component analysis (PCA) was used to derive general toxicity profiles from the in vitro screening data. The toxicity profiles indicated different structure-activity relationships (SAR) and distinct mechanisms of action. The analysis also indicated that the NDL-PCBs could be divided into two groups. The first group included generally smaller, ortho-substituted congeners, comprising PCB 28, 47, 51, 52, 53, 95, 100, 101, 104 and 136, with PCB 95, 101 and 136 as generally being most active. The second group comprising PCB 19, 74, 118, 122, 128, 138, 153, 170, 180 and 190 had lower biological activity in many of the assays, except for three endocrine-related assays. The most abundant congeners, PCB 138, 153, 170, 180 and 190, cluster in the second group, and thereby show similar SAR. Two quantitative structure-activity relationship (QSAR) models could be developed that added information to the SAR and could aid in risk assessments of NDL-PCBs. The QSAR models predicted a number of congeners as active and among these e.g., PCB 18, 25, 45 and 49 have been found in food or human samples.
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Affiliation(s)
- Mia Stenberg
- Department of Chemistry, Umeå University, Umeå, Sweden.
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27
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Modulation of gap-junctional intercellular communication by a series of cyanobacterial samples from nature and laboratory cultures. Toxicon 2011; 58:76-84. [PMID: 21619891 DOI: 10.1016/j.toxicon.2011.05.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 05/07/2011] [Accepted: 05/10/2011] [Indexed: 11/21/2022]
Abstract
Cyanobacterial extracts have been recently shown to alter two in vitro biomarkers of tumor promotion, namely to cause inhibition of gap-junctional intercellular communication (GJIC) and activation of mitogen-activated protein kinases (Blaha et al., 2010a). In the present study, we investigated GJIC-inhibitory potencies of 10 laboratory strains representing common water bloom-forming cyanobacteria (Anabaena, Aphanizomenon, Cylindrospermopsis, Microcystis and Planktothrix) and six natural water bloom samples (dominated by Aphanizomenon sp. or Microcystis). The most pronounced inhibitions of GJIC in a model rat liver epithelial cell line WB-F344 were caused by methanolic extracts of Anabaena flos-aquae UTEX 1444, Aphanizomenon flos-aquae SAG 31.87, Aphanizomenon gracile RCX 06, Microcystis aeruginosa PCC 7806, Cylindrospermopsis raciborskii SAG 1.97, Planktothrix agardhii CCALA 159 and SAG 32.79, whereas weaker effects were induced by Aphanizomenon klebahnii CCALA 009 and no inhibition was induced by extracts of Aph. flos-aquae PCC 7905 and Aph. gracile SAG 31.79. Exudates of the laboratory cultured strains concentrated by solid phase extraction also induced species-specific inhibitory effects, but they did not necessarily correlate with the inhibitory potencies of extracts from the corresponding species. Interestingly, the GJIC-inhibitory effects may not be restricted to cyanobacteria, since exudates of two green alga species also affected GJIC, although their extracts caused no effects. The extracts from different natural water blooms inhibited GJIC with different potencies without apparent relation to bloom-species composition. Since the observed effects on GJIC did not correlate with the content of cyanotoxins microcystins and cylindrospermopsin in the tested samples, they were most likely induced by unknown compound(s). Our results indicate that putative tumor promoting compound(s) could be associated with different species of bloom-forming cyanobacteria, but their production is probably species- and strain-specific.
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28
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Marabini L, Calò R, Fucile S. Genotoxic effects of polychlorinated biphenyls (PCB 153, 138, 101, 118) in a fish cell line (RTG-2). Toxicol In Vitro 2011; 25:1045-52. [PMID: 21504788 DOI: 10.1016/j.tiv.2011.04.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 04/01/2011] [Accepted: 04/04/2011] [Indexed: 01/12/2023]
Abstract
Polychlorinated biphenyls (PCBs) are persistent pollutants in aquatic environments, often causing the decline or disappearance of wild populations. The primary aim of this study was to investigate the genotoxic effects of some PCBs (PCB153 (2,2',4,4',5,5'-hexachlorobiphenyl) and 138 (2,2',3,4,4',5'-hexachloro-biphenyl), both non-dioxin-like compounds, and the pentachlorobiphenyls PCB118 (2,3',4,4',5-) and 101 (2,2',4',5,5'-), the former an ortho-substituted, low-affinity dioxin-like compound and the latter a non-coplanar congener classified as non-dioxin-like) in fish cells (RTG-2). These congeners are mostly present in surface waters and in edible aquatic organisms and the loss of DNA integrity in vitro serves as a sensitive biomarker of cytogenetic alterations and is considered as an initial step for the identification of genotoxic effects. The alkaline comet assay and the micronucleus test show clear genotoxic damage after short and longer exposure (2 and 24h) to maximum soluble, non-cytotoxic doses, evident sooner with PCBs 101 and 118. Oxidative stress situations involving ROS release, reduction in total GSH, lipid peroxidation and alteration to superoxide dismutase, seen after exposure with all the congeners, though with different kinetics, seem the most likely explanation for the genotoxic damage. This appears to be confirmed by the modified comet assay (pH 10) for detection of oxidized bases using endonuclease III. The increased generation of intracellular ROS might explain the apoptosis seen after treatment with the single PCBs and evaluated on the basis of the rise in 3-7 caspase activity. Therefore both the non-coplanar, non-dioxin-like PCBs (153, 138, 101) and the low-affinity dioxin-like compound PCB118 cause evident genotoxic damage, probably as a consequence of oxidative stress.
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Affiliation(s)
- Laura Marabini
- Università degli Studi di Milano, Department of Pharmacology, Chemotherapy and Medical Toxicology E. Trabucchi, via Vanvitelli 32, 20129 Milano, Italy.
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Lübcke-von Varel U, Machala M, Ciganek M, Neca J, Pencikova K, Palkova L, Vondracek J, Löffler I, Streck G, Reifferscheid G, Flückiger-Isler S, Weiss JM, Lamoree M, Brack W. Polar compounds dominate in vitro effects of sediment extracts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:2384-2390. [PMID: 21348526 DOI: 10.1021/es103381y] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Sediment extracts from three polluted sites of the river Elbe basin were fractionated using a novel online fractionation procedure. Resulting fractions were screened for mutagenic, aryl hydrocarbon receptor (AhR)-mediated, transthyretin (TTR)-binding, and estrogenic activities and their potency to inhibit gap junctional intercellular communication (GJIC) to compare toxicity patterns and identify priority fractions. Additionally, more than 200 compounds and compound classes were identified using GC-MS/MS, LC-MS/MS, and HPLC-DAD methods. For all investigated end points, major activities were found in polar fractions, which are defined here as fractions containing dominantly compounds with at least one polar functional group. Nonpolar PAH fractions contributed to mutagenic and AhR-mediated activities while inhibition of GJIC and estrogenic and TTR-binding activities were exclusively observed in the polar fractions. Known mutagens in polar fractions included nitro- and dinitro-PAHs, azaarenes, and keto-PAHs, while parent and monomethylated PAHs such as benzo[a]pyrene and benzofluoranthenes were identified in nonpolar fractions. Additionally, for one sample, high AhR-mediated activities were determined in one fraction characterized by PCDD/Fs, PCBs, and PCNs. Estrone, 17β-estradiol, 9H-benz[de]anthracen-7-one, and 4-nonylphenol were identified as possible estrogenic and TTR-binding compounds. Thus, not only nonpolar compounds such as PAHs, PCBs, and PCDD/Fs but also the less characterized and investigated more polar substances should be considered as potent mutagenic, estrogenic, AhR-inducing, TTR-binding, and GJIC-inhibiting components for future studies.
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Hamers T, Kamstra JH, Cenijn PH, Pencikova K, Palkova L, Simeckova P, Vondracek J, Andersson PL, Stenberg M, Machala M. In Vitro Toxicity Profiling of Ultrapure Non–Dioxin-like Polychlorinated Biphenyl Congeners and Their Relative Toxic Contribution to PCB Mixtures in Humans. Toxicol Sci 2011; 121:88-100. [DOI: 10.1093/toxsci/kfr043] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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De S, Ghosh S, Chatterjee R, Chen YQ, Moses L, Kesari A, Hoffman E, Dutta SK. PCB congener specific oxidative stress response by microarray analysis using human liver cell line. ENVIRONMENT INTERNATIONAL 2010; 36:907-917. [PMID: 20638727 PMCID: PMC3018769 DOI: 10.1016/j.envint.2010.05.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Revised: 05/13/2010] [Accepted: 05/23/2010] [Indexed: 05/29/2023]
Abstract
In this study we have examined the effect of exposure to different congeners of PCBs and their role in oxidative stress response. A metabolically competent human liver cell line (HepG2) was exposed with two prototype congeners of PCBs: coplanar PCB-77 and non-coplanar PCB-153. After the predetermined times of exposure (0-24h) at 70 μM concentration, the HepG2 cells showed significant apoptotic changes by fluorescent microscopy after 12h of exposure. Gene set enrichment analysis (GSEA) identified oxidative stress as the predominant enrichment. Further, paraquat assay showed that PCB congeners lead to oxidative stress to different extents, PCB-77 being more toxic. This study, with emphasis on all recommended microarray quality control steps, showed that apoptosis was one of the most significant cellular processes as a result of oxidative stress, but each of these congeners had a unique signature gene expression, which was further validated by Taqman real time PCR and immunoblotting. The pathways involved leading to the common apoptotic effect were completely different. Further in-silico analysis showed that PCB-153 most likely acted through the TNF receptor, leading to oxidative stress involving metallothionein gene families, and causing apoptosis mainly by the Fas receptor signaling pathway. In contrast, PCB-77 acted through the aryl hydrocarbon receptor. It induced oxidative stress through the involvement of cytochrome P450 (CYP1A1) leading to apoptosis through AHR/ARNT pathway.
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Affiliation(s)
- Supriyo De
- Department of Biology, Howard University, Washington DC
| | | | | | - Y-Q Chen
- Department of Biology, Howard University, Washington DC
| | - Linda Moses
- Children’s National Medical Center, Washington DC
| | | | - Eric Hoffman
- Children’s National Medical Center, Washington DC
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Kodavanti PRS, Curras-Collazo MC. Neuroendocrine actions of organohalogens: thyroid hormones, arginine vasopressin, and neuroplasticity. Front Neuroendocrinol 2010; 31:479-96. [PMID: 20609372 DOI: 10.1016/j.yfrne.2010.06.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 06/22/2010] [Accepted: 06/25/2010] [Indexed: 02/08/2023]
Abstract
Organohalogen compounds are global environmental pollutants. They are highly persistent, bioaccumulative, and cause adverse effects in humans and wildlife. Because of the widespread use of these organohalogens in household items and consumer products, indoor contamination may be a significant source of human exposure, especially for children. One significant concern with regard to health effects associated with exposure to organohalogens is endocrine disruption. This review focuses on PCBs and PBDEs as old and new organohalogens, respectively, and their effects on two neuroendocrine systems; thyroid hormones and the arginine vasopressin system (AVP). Regarding neuroendocrine effects of organohalogens, there is considerable information on the thyroid system as a target and evidence is now accumulating that the AVP system and associated functions are also susceptible to disruption. AVP-mediated functions such as osmoregulation, cardiovascular function as well as social behavior, sexual function and learning/memory are discussed. For both thyroid and AVP systems, the timing of exposure seems to play a major role in the outcome of adverse effects. The mechanism of organohalogen action is well understood for the thyroid system. In comparison, this aspect is understudied in the AVP system but some similarities in neural processes, shown to be targeted by these pollutants, serve as promising possibilities for study. One challenge in understanding modes of action within neuroendocrine systems is their complexity stemming, in part, from interdependent levels of organization. Further, because of the interplay between neuroendocrine and neural functions and behavior, further investigation into organohalogen-mediated effects is warranted and may yield insights with wider scope. Indeed, the current literature provides scattered evidence regarding the role of organohalogen-induced neuroendocrine disruption in the neuroplasticity related to both learning functions and brain structure but future studies are needed to establish the role of endocrine disruption in nervous system function and development.
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Affiliation(s)
- Prasada Rao S Kodavanti
- Neurotoxicology Branch, Toxicity Assessment Division, B 105-06, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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Rivedal E, Witz G, Leithe E. Gap junction intercellular communication and benzene toxicity. Chem Biol Interact 2010; 184:229-32. [DOI: 10.1016/j.cbi.2009.11.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 10/21/2009] [Accepted: 11/16/2009] [Indexed: 11/28/2022]
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Non-dioxin-like-PCBs phosphorylate Mdm2 at Ser166 and attenuate the p53 response in HepG2 cells. Chem Biol Interact 2009; 182:191-8. [DOI: 10.1016/j.cbi.2009.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 08/20/2009] [Accepted: 09/06/2009] [Indexed: 11/17/2022]
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Vinken M, Doktorova T, Decrock E, Leybaert L, Vanhaecke T, Rogiers V. Gap junctional intercellular communication as a target for liver toxicity and carcinogenicity. Crit Rev Biochem Mol Biol 2009; 44:201-22. [PMID: 19635038 DOI: 10.1080/10409230903061215] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Direct communication between hepatocytes, mediated by gap junctions, constitutes a major regulatory platform in the control of liver homeostasis, ranging from hepatocellular proliferation to hepatocyte cell death. Inherent to this pivotal task, gap junction functionality is frequently disrupted upon impairment of the homeostatic balance, as occurs during liver toxicity and carcinogenicity. In the present paper, the deleterious effects of a number of chemical and biological toxic compounds on hepatic gap junctions are discussed, including environmental pollutants, biological toxins, organic solvents, pesticides, pharmaceuticals, peroxides, metals and phthalates. Particular attention is paid to the molecular mechanisms that underlie the abrogation of gap junction functionality. Since hepatic gap junctions are specifically targeted by tumor promoters and epigenetic carcinogens, both in vivo and in vitro, inhibition of gap junction functionality is considered as a suitable indicator for the detection of nongenotoxic hepatocarcinogenicity.
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Affiliation(s)
- Mathieu Vinken
- Department of Toxicology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium.
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36
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Hernández LG, van Steeg H, Luijten M, van Benthem J. Mechanisms of non-genotoxic carcinogens and importance of a weight of evidence approach. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2009; 682:94-109. [DOI: 10.1016/j.mrrev.2009.07.002] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 06/29/2009] [Accepted: 07/13/2009] [Indexed: 01/20/2023]
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Bláha L, Babica P, Hilscherová K, Upham BL. Inhibition of gap-junctional intercellular communication and activation of mitogen-activated protein kinases by cyanobacterial extracts--indications of novel tumor-promoting cyanotoxins? Toxicon 2009; 55:126-34. [PMID: 19619572 DOI: 10.1016/j.toxicon.2009.07.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 07/09/2009] [Accepted: 07/13/2009] [Indexed: 10/20/2022]
Abstract
Toxicity and liver tumor promotion of cyanotoxins microcystins have been extensively studied. However, recent studies document that other metabolites present in the complex cyanobacterial water blooms may also have adverse health effects. In this study we used rat liver epithelial stem-like cells (WB-F344) to examine the effects of cyanobacterial extracts on two established markers of tumor promotion, inhibition of gap-junctional intercellular communication (GJIC) and activation of mitogen-activated protein kinases (MAPKs) - ERK1/2. Extracts of cyanobacteria (laboratory cultures of Microcystis aeruginosa and Aphanizomenon flos-aquae and water blooms dominated by these species) inhibited GJIC and activated MAPKs in a dose-dependent manner (effective concentrations ranging 0.5-5mgd.w./mL). Effects were independent of the microcystin content and the strongest responses were elicited by the extracts of Aphanizomenon sp. Neither pure microcystin-LR nor cylindrospermopsin inhibited GJIC or activated MAPKs. Modulations of GJIC and MAPKs appeared to be specific to cyanobacterial extracts since extracts from green alga Chlamydomonas reinhardtii, heterotrophic bacterium Klebsiella terrigena, and isolated bacterial lipopolysaccharides had no comparable effects. Our study provides the first evidence on the existence of unknown cyanobacterial toxic metabolites that affect in vitro biomarkers of tumor promotion, i.e. inhibition of GJIC and activation of MAPKs.
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Affiliation(s)
- Ludĕk Bláha
- Institute of Botany, Academy of Sciences, Lidická 25/27, CZ65720 Brno, Czech Republic
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38
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2,2′,4,4′,5,5′-Hexachlorobiphenyl (PCB 153) induces degradation of adherens junction proteins and inhibits β-catenin-dependent transcription in liver epithelial cells. Toxicology 2009; 260:104-11. [DOI: 10.1016/j.tox.2009.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 03/17/2009] [Accepted: 03/18/2009] [Indexed: 12/16/2022]
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39
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Upham BL, Park JS, Babica P, Sovadinova I, Rummel AM, Trosko JE, Hirose A, Hasegawa R, Kanno J, Sai K. Structure-activity-dependent regulation of cell communication by perfluorinated fatty acids using in vivo and in vitro model systems. ENVIRONMENTAL HEALTH PERSPECTIVES 2009; 117:545-51. [PMID: 19440492 PMCID: PMC2679597 DOI: 10.1289/ehp.11728] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Accepted: 10/23/2008] [Indexed: 05/24/2023]
Abstract
BACKGROUND Perfluoroalkanoates, [e.g., perfluorooctanoate (PFOA)], are known peroxisome proliferators that induce hepatomegaly and hepatocarcinogenesis in rodents, and are classic non-genotoxic carcinogens that inhibit in vitro gap-junctional intercellular communication (GJIC). This inhibition of GJIC is known to be a function of perfluorinated carbon lengths ranging from 7 to 10. OBJECTIVES The aim of this study was to determine if the inhibition of GJIC by PFOA but not perfluoropentanoate (PFPeA) observed in F344 rat liver cells in vitro also occurs in F344 rats in vivo and to determine mechanisms of PFOA dysregulation of GJIC using in vitro assay systems. METHODS We used an incision load/dye transfer technique to assess GJIC in livers of rats exposed to PFOA and PFPeA. We used in vitro assays with inhibitors of cell signaling enzymes and antioxidants known to regulate GJIC to identify which enzymes regulated PFOA-induced inhibition of GJIC. RESULTS PFOA inhibited GJIC and induced hepatomegaly in rat livers, whereas PFPeA had no effect on either end point. Serum biochemistry of liver enzymes indicated no cytotoxic response to these compounds. In vitro analysis of mitogen-activated protein kinase (MAPK) indicated that PFOA, but not PFPeA, can activate the extracellular receptor kinase (ERK). Inhibition of GJIC, in vitro, by PFOA depended on the activation of both ERK and phosphatidylcholine-specific phospholipase C (PC-PLC) in the dysregulation of GJIC in an oxidative-dependent mechanism. CONCLUSIONS The in vitro analysis of GJIC, an epigenetic marker of tumor promoters, can also predict the in vivo activity of PFOA, which dysregulated GJIC via ERK and PC-PLC.
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Affiliation(s)
- Brad L Upham
- Department of Pediatrics and Human Development, National Food Safety and Toxicology Center, Michigan State University, East Lansing, Michigan 48824, USA.
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Hattis D, Chu M, Rahmioglu N, Goble R, Verma P, Hartman K, Kozlak M. A preliminary operational classification system for nonmutagenic modes of action for carcinogenesis. Crit Rev Toxicol 2009; 39:97-138. [PMID: 19009457 DOI: 10.1080/10408440802307467] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This article proposes a system of categories for nonmutagenic modes of action for carcinogenesis. The classification is of modes of action rather than individual carcinogens, because the same compound can affect carcinogenesis in more than one way. Basically, we categorize modes of action as: (1) co-initiation (facilitating the original mutagenic changes in stem and progenitor cells that start the cancer process) (e.g. induction of activating enzymes for other carcinogens); (2) promotion (enhancing the relative growth vs differentiation/death of initiated clones (e.g. inhibition of growth-suppressing cell-cell communication); (3) progression (enhancing the growth, malignancy, or spread of already developed tumors) (e.g. suppression of immune surveillance, hormonally mediated growth stimulation for tumors with appropriate receptors by estrogens); and (4) multiphase (e.g., "epigenetic" silencing of tumor suppressor genes). A priori, agents that act at relatively early stages in the process are expected to manifest greater relative susceptibility in early life, whereas agents that act via later stage modes will tend to show greater susceptibility for exposures later in life.
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Affiliation(s)
- D Hattis
- George Perkins Marsh Institute, Clark University, Worcester, Massachusetts, USA
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Kovacic P, Pozos RS. Bioelectronome. Integrated Approach to Receptor Chemistry, Radicals, Electrochemistry, Cell Signaling, and Physiological Effects Based on Electron Transfer. J Recept Signal Transduct Res 2008; 27:261-94. [PMID: 17885922 DOI: 10.1080/10799890701509133] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Bioelectronome refers to the host of electron transfer (ET) reactions that occur in living systems. This review presents an integrated approach to receptor chemistry based on electron transfer, radicals, electrochemistry, cell signaling, and end result. First, receptor activity is addressed from the unifying standpoint of redox transformations in which various receptors are discussed. After a listing of receptor-binding modes, receptor chemistry is treated with focus on generation of reactive oxygen species (ROS), activation by ROS, and subsequent cell signaling involving ROS. A general electrostatic mechanism is proposed for receptor-ligand action with supporting evidence. Cell-signaling processes appear to entail electron transfer, ROS, redox chains, and relays. The widespread involvement of phosphate from phosphorylation may be rationalized electrostatically by analogy with DNA phosphate. Extensive evidence supports important participation of ET functionalities in the mechanism of drugs and toxins. The integrated approach is applied to the main ET classes, namely, quinones, metal complexes, iminium species, and aromatic nitro compounds.
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Affiliation(s)
- Peter Kovacic
- Department of Chemistry, San Diego State University, San Diego, California 92182, USA.
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Šimečková P, Vondráček J, Andrysík Z, Zatloukalová J, Krčmář P, Kozubík A, Machala M. The 2,2′,4,4′,5,5′-Hexachlorobiphenyl–Enhanced Degradation of Connexin 43 Involves Both Proteasomal and Lysosomal Activities. Toxicol Sci 2008; 107:9-18. [DOI: 10.1093/toxsci/kfn202] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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43
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Nakazawa Y, Saenko V, Rogounovitch T, Suzuki K, Mitsutake N, Matsuse M, Yamashita S. Reciprocal paracrine interactions between normal human epithelial and mesenchymal cells protect cellular DNA from radiation-induced damage. Int J Radiat Oncol Biol Phys 2008; 71:567-77. [PMID: 18474314 DOI: 10.1016/j.ijrobp.2007.10.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2007] [Revised: 10/11/2007] [Accepted: 10/20/2007] [Indexed: 11/30/2022]
Abstract
PURPOSE To explore whether interactions between normal epithelial and mesenchymal cells can modulate the extent of radiation-induced DNA damage in one or both types of cells. METHODS AND MATERIALS Human primary thyrocytes (PT), diploid fibroblasts BJ, MRC-5, and WI-38, normal human mammary epithelial cells (HMEC), and endothelial human umbilical cord vein endothelial cells (HUV-EC-C), cultured either individually or in co-cultures or after conditioned medium transfer, were irradiated with 0.25 to 5 Gy of gamma-rays and assayed for the extent of DNA damage. RESULTS The number of gamma-H2AX foci in co-cultures of PT and BJ fibroblasts was approximately 25% lower than in individual cultures at 1 Gy in both types of cells. Reciprocal conditioned medium transfer to individual cultures before irradiation resulted in approximately a 35% reduction of the number gamma-H2AX foci at 1 Gy in both types of cells, demonstrating the role of paracrine soluble factors. The DNA-protected state of cells was achieved within 15 min after conditioned medium transfer; it was reproducible and reciprocal in several lines of epithelial cells and fibroblasts, fibroblasts, and endothelial cells but not in epithelial and endothelial cells. Unlike normal cells, human epithelial cancer cells failed to establish DNA-protected states in fibroblasts and vice versa. CONCLUSIONS The results imply the existence of a network of reciprocal interactions between normal epithelial and some types of mesenchymal cells mediated by soluble factors that act in a paracrine manner to protect DNA from genotoxic stress.
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Affiliation(s)
- Yuka Nakazawa
- Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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Umannová L, Neča J, Andrysík Z, Vondráček J, Upham B, Trosko J, Hofmanová J, Kozubík A, Machala M. Non-dioxin-like polychlorinated biphenyls induce a release of arachidonic acid in liver epithelial cells: a partial role of cytosolic phospholipase A(2) and extracellular signal-regulated kinases 1/2 signalling. Toxicology 2008; 247:55-60. [PMID: 18367304 PMCID: PMC2577785 DOI: 10.1016/j.tox.2008.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 02/06/2008] [Accepted: 02/06/2008] [Indexed: 01/07/2023]
Abstract
Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) have been shown to act as tumor promoters in liver; however, the exact mechanisms of their action are still only partially understood. One of the interesting effects of NDL-PCBs is the acute inhibition of gap junctional intercellular communication (GJIC), an effect, which has been often found to be associated with tumor promotion. As previous studies have suggested that NDL-PCB-induced disruption of lipid signalling pathways might correspond with GJIC inhibition, we investigated effects of PCBs on the release of arachidonic acid (AA) in the rat liver epithelial WB-F344 cell line, a well-established model of liver progenitor cells. We found that both 2,2',4,4'-tetrachlorobiphenyl (PCB 47) and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153), but not the dioxin-like, non-ortho-substituted, 3,3',4,4',5-pentachlorobiphenyl (PCB 126), induce a massive release of AA. The AA release, induced by PCB 153, was partially inhibited by extracellular signal-regulated kinases 1/2 (ERK1/2) signalling inhibitor, U0126, and by cytosolic phospholipase A(2) (cPLA(2)) inhibitor, AACOCF(3). Although PCB 153 induced both ERK1/2 and p38 activation, the specific p38 kinase inhibitor, SB203580, had no effect on AA release. Inhibitors of other phospholipases, including phosphatidylcholine-specific phospholipase C or phosphatidylinositol-specific phospholipase C, were also without effect. Taken together, our findings suggest that the AA release, induced by non-dioxin-like PCBs in liver progenitor cell line, is partially mediated by cytosolic PLA(2) and regulated by ERK1/2 kinases. Our results suggest that more attention should be paid to cell signalling pathways regulated by AA or eicosanoids after PCB exposure, which might be involved in their toxic effects.
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Affiliation(s)
- L. Umannová
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - J. Neča
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - Z. Andrysík
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
| | - J. Vondráček
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - B.L. Upham
- National Food Safety & Toxicology Center, Michigan State University, East Lansing MI 48824, USA
| | - J.E. Trosko
- National Food Safety & Toxicology Center, Michigan State University, East Lansing MI 48824, USA
| | - J. Hofmanová
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Institute of Experimental Biology, Faculty of Science, Masaryk University, 611 37 Brno, Czech Republic
| | - A. Kozubík
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Institute of Experimental Biology, Faculty of Science, Masaryk University, 611 37 Brno, Czech Republic
| | - M. Machala
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
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Stenberg M, Andersson PL. Selection of non-dioxin-like PCBs for in vitro testing on the basis of environmental abundance and molecular structure. CHEMOSPHERE 2008; 71:1909-1915. [PMID: 18281077 DOI: 10.1016/j.chemosphere.2008.01.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 12/21/2007] [Accepted: 01/03/2008] [Indexed: 05/25/2023]
Abstract
The non-dioxin-like polychlorinated biphenyls (NDL-PCBs) constitute the major proportion of PCBs found in food and human tissues. It is important to improve our understanding of the toxicity, environmental and human risks associated with the NDL-PCBs, since their toxicology is incompletely characterized and a human health risk assessment is required. This paper discusses the selection of a training set of 20 tri- to hepta-chlorinated biphenyls, PCBs 19,28,47,51,52,53,74,95,100,101,104,118,122,128,136,138,153,170,180, and 190. Suggested for comprehensive screening using in vitro assays to identify critical mechanisms of toxicological action. The selected PCBs form a balanced basis for developing of quantitative structure-activity relationship (QSAR) models for prediction of physicochemical and toxicological properties of non-tested PCB congeners. Chemical and physical properties, environmental abundance and toxicological activities of the congeners were considered during the selection process. A complementary set of PCBs, a reference set, was selected using D-optimal onion design including PCBs 18,20,28,30,37,40,50,54,60,77,82,99,122,132,153,161,170,188,192, and 193. Congeners of this set are well suited for validation of QSAR models developed using the training set. For visualization of the chemical diversity of environmentally abundant PCBs and congeners of the training and reference sets, principal component analysis (PCA) was used. Statistical molecular design was used to verify the structural representation. As a reference structure for dioxin-like PCBs, PCB 126 was added in the training set. The selected set of NDL-PCBs is proposed for use in toxicological testing programs to provide rational basis for risk assessment of the NDL-PCBs.
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Affiliation(s)
- Mia Stenberg
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
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46
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Chaumontet C, Bex V, Véran F, Martel P. The vitamin E analog tocopherol succinate strongly inhibits gap junctional intercellular communication in rat liver epithelial cells (IAR203). J Nutr Biochem 2008; 19:263-8. [PMID: 17683923 DOI: 10.1016/j.jnutbio.2007.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 02/01/2007] [Accepted: 03/27/2007] [Indexed: 01/09/2023]
Abstract
Vitamin E is a scavenger molecule trapping free radicals in biological membranes. However, it has also been shown to elicit the formation of reactive oxygen species and apoptosis in cancer cells. In this study, we tested the ability of alpha-tocopherol, tocopherol acetate, tocopherol phosphate and tocopherol succinate (TS) to modulate gap junctional intercellular communication in the rat liver epithelial cell line IAR203, as measured by the transfer of Lucifer yellow. While alpha-tocopherol, tocopherol acetate and tocopherol phosphate moderately reduced the dye transfer, TS at 10 and 25 microM strongly inhibited it, probably via the induction of the hypophosphorylation of connexin 43. Our results show that, besides their interesting antioxidant properties, vitamin E analogs, especially TS, can exert adverse effects on gap junctional intercellular communication, which could explain their controversial effects in carcinogenesis.
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Affiliation(s)
- Catherine Chaumontet
- Laboratoire de Nutrition et Sécurité Alimentaire, INRA, Domaine de Vilvert, Jouy-en-Josas Cedex, France.
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47
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Upham BL, Bláha L, Babica P, Park JS, Sovadinova I, Pudrith C, Rummel AM, Weis LM, Sai K, Tithof PK, Guzvić M, Vondrácek J, Machala M, Trosko JE. Tumor promoting properties of a cigarette smoke prevalent polycyclic aromatic hydrocarbon as indicated by the inhibition of gap junctional intercellular communication via phosphatidylcholine-specific phospholipase C. Cancer Sci 2008; 99:696-705. [PMID: 18377422 PMCID: PMC3023995 DOI: 10.1111/j.1349-7006.2008.00752.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Inhibition of gap junctional intercellular communication (GJIC) and the activation of intracellular mitogenic pathways are common hallmarks of epithelial derived cancer cells. We previously determined that the 1-methyl and not the 2-methyl isomer of anthracene, which are prominent cigarette smoke components, activated extracellular receptor kinase, and inhibited GJIC in WB-F344 rat liver epithelial cells. Using these same cells, we show that an immediate upstream response to 1-methylanthracene was a rapid (<1 min) release of arachidonic acid. Inhibition of phosphatidylcholine-specific phospholipase C prevented the inhibition of GJIC by 1-methylanthracene. In contrast, inhibition of phosphatidylinositol specific phospholipase C, phospholipase A(2), diacylglycerol lipase, phospholipase D, protein kinase C, and tyrosine protein kinases had no effect on 1-methylanthracene-induced inhibition of GJIC. Inhibition of protein kinase A also prevented inhibition of GJIC by 1-methylanthracene. Direct measurement of phosphatidylcholine-specific phospholipase C and sphingomyelinase indicated that only phosphatidylcholine-specific phospholipase C was activated in response to 1-methylanthracene, while 2-methylanthracene had no effect. 1-methylanthracene also activated p38-mitogen activated protein kinase; however, like extracellular kinase, its activation was not involved in 1-methylanthracene-induced regulation of GJIC, and this activation was independent of phosphatidylcholine-specific phospholipase C. Although mitogen activated protein kinases were activated, Western blot analyzes indicated no change in connexin43 phosphorylation status. Our results indicate that phosphatidylcholine-specific phospholipase C is an important enzyme in the induction of a tumorigenic phenotype, namely the inhibition of GJIC; whereas mitogen activated protein kinases triggered in response to 1-methylanthracene, were not involved in the deregulation of GJIC.
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Affiliation(s)
- Brad L Upham
- Department of Pediatrics & Human Development, Michigan State University, East Lansing, MI 48824, USA.
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48
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Sipka S, Eum SY, Son KW, Xu S, Gavalas VG, Hennig B, Toborek M. ORAL ADMINISTRATION OF PCBs INDUCES PROINFLAMMATORY AND PROMETASTATIC RESPONSES. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2008; 25:251-9. [PMID: 18438459 PMCID: PMC2346434 DOI: 10.1016/j.etap.2007.10.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Exposure to specific congeners of polychlorinated biphenyls (PCBs) can induce proinflammatory alterations, which may contribute to the formation of blood-borne tumor metastasis. The main aim of the present study was to establish an experimental model of PCB exposure in which PCBs are administered by oral gavage, which resembles the human exposure through the food chain. To determine structure-function relationship, we studied induction of inflammatory responses in the livers, lungs and brains of mice treated with PCB77 (a major coplanar PCB), PCB104 (a non-coplanar PCB with multiple ortho-chlorine substituents), and PCB153 (a major non-coplanar PCB) after a single gavage dose (150 µmol/kg body weight). The strongest expression of proinflammatory proteins occurred 24 h following the PCB administration independent of the class of PCB congeners. These data indicate that food-chain exposure to PCBs can induce proinflammatory mediators in organs that are potential targets for PCB-induced toxicity.
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Affiliation(s)
- Sandor Sipka
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky, Lexington, KY 40536
| | - Sung-Yong Eum
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky, Lexington, KY 40536
| | - Kwang Won Son
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky, Lexington, KY 40536
| | - Shifen Xu
- Department of Chemistry, University of Kentucky, Lexington, KY 40536
| | | | - Bernhard Hennig
- College of Agriculture, University of Kentucky, Lexington, KY 40536
| | - Michal Toborek
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky, Lexington, KY 40536
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49
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Kim JH, Kang NJ, Lee BK, Lee KW, Lee HJ. Gallic acid, a metabolite of the antioxidant propyl gallate, inhibits gap junctional intercellular communication via phosphorylation of connexin 43 and extracellular-signal-regulated kinase1/2 in rat liver epithelial cells. Mutat Res 2008; 638:175-183. [PMID: 18054051 DOI: 10.1016/j.mrfmmm.2007.10.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 10/07/2007] [Accepted: 10/08/2007] [Indexed: 05/25/2023]
Abstract
Propyl gallate and its metabolite, gallic acid, are widely used as antioxidants in the food industry, but they have been shown to exhibit liver toxicity and enhance carcinogenesis. In the present study, we investigated the possible undesirable effects of propyl gallate and gallic acid on gap junctional intercellular communication (GJIC), inhibition of which is closely linked to carcinogenesis. Gallic acid and propyl gallate exhibited dose-dependent free-radical-scavenging activities as determined by 1,1-diphenyl-2-picrylhydrazyl- or 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-radical-scavenging assays, and the free-radical-scavenging activity of gallic acid was stronger than that of propyl gallate. However, using WB-F344 rat liver epithelial cells, gallic acid inhibited GJIC in a dose-dependent manner, while propyl gallate had no significant effect compared with untreated controls. The gallic-acid-induced inhibition of GJIC was reversible, with a recovery of nearly 65% after 120 min. Gallic acid induced the phosphorylation of connexin 43 (Cx43) and phosphorylation of extracellular-signal-regulated kinase1/2 (ERK1/2). The gallic-acid-induced inhibition of GJIC was attenuated by treatment with mitogen-activated protein kinase kinase inhibitors (U0126 and PD098059). U0126 blocked the gallic-acid-induced phosphorylation of Cx43 and ERK1/2, indicating that the gallic-acid-induced inhibition of GJIC is mediated by phosphorylation of Cx43 via activation of ERK1/2. In addition, gallic-acid-induced inhibition of GJIC was protected by ascorbic acid and quercetin, which might represent a simple example of the different effects of natural antioxidants in carcinogenesis.
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Affiliation(s)
- Jong Hun Kim
- Department of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921, Republic of Korea
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50
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Brown JF, Mayes BA, Silkworth JB, Hamilton SB. Polychlorinated biphenyls modulated tumorigenesis in Sprague Dawley rats: correlation with mixed function oxidase activities and superoxide (O2* ) formation potentials and implied mode of action. Toxicol Sci 2007; 98:375-94. [PMID: 17510085 DOI: 10.1093/toxsci/kfm122] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Parallel, chronic (24 months) multidose bioassays of the PCB (polychlorinated biphenyls) Aroclors 1016, 1242, 1254, and 1260 in male and female Sprague-Dawley rats showed sex/Aroclor-dependent increases in hepatic tumors and decreases in extrahepatic tumors. To elucidate the PCB mode of action (MOA) involved, levels of a number of hypothesized mediators were measured in liver specimens collected at 3, 6, 12, 18, and 24 months and screened for correlation with late life hepatotumorigenesis (HT; mostly adenomas). Consistently correlated with HT were (1) tissue accumulations of SigmaPCBs (correlated in both sexes) and of dioxin equivalents (toxic equivalency [TEQ]; correlated in females only); (2) net activities of six groups of mixed function oxidases (MFOs), some PCB-induced, some PCB-repressed, as determined by differential metabolism of PCB congeners; (3) activities of deproteinated, reoxidized hepatic cytosols as catalysts for superoxide (O(2)(*-)) production, such activity having the chemical characteristics of redox-cycling quinones (RCQs), e.g., those derived from the glutathionylated estrogen catechols that were identified in the female rat livers; and (4) increased expression of the indicator of cell proliferation, proliferating cell nuclear antigen. The new findings, along with other recently reported relationships, were indicative of a MOA consisting of (1) SigmaPCB/TEQ accumulation in rat tissues; (2) SigmaPCB/TEQ repression of constitutive MFOs; (3) SigmaPCB/TEQ induction of other MFOs; (4) MFO-mediated formation of RCQs; (5) RCQ-mediated formation of O(2)(*-); (6) O(2)(*-) dismutation to H(2)O(2); and (7) H(2)O(2)-mediated mitotic signaling, resulting in the proliferation of spontaneously or otherwise initiated cells to form hepatic tumors, as in tumor promotion.
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Affiliation(s)
- John F Brown
- General Electric Company, Fairfield, Connecticut 06431, USA.
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