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Mrdjen I, Lee J, Weghorst CM, Knobloch TJ. Impact of Cyanotoxin Ingestion on Liver Cancer Development Using an At-Risk Two-Staged Model of Mouse Hepatocarcinogenesis. Toxins (Basel) 2022; 14:toxins14070484. [PMID: 35878222 PMCID: PMC9320861 DOI: 10.3390/toxins14070484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/05/2022] [Accepted: 07/06/2022] [Indexed: 12/04/2022] Open
Abstract
Exposure to cyanobacterial hepatotoxins has been linked to the promotion and increased incidence of liver cancer in pre-clinical and epidemiologic studies. The family of hepatotoxins, microcystins (MCs), are produced by over 40 cyanobacterial species found in harmful algal blooms (HABs) worldwide, with MC-LR being the most common and potent MC congener. In the current study, we hypothesized that the low-dose chronic ingestion of Microcystis cyanotoxins via drinking water would promote liver carcinogenesis in pre-initiated mice. Four groups of C3H/HeJ mice received one intraperitoneal (i.p.) injection of diethylnitrosamine (DEN) at 4 weeks of age. Three weeks later, the mice were administered ad libitum drinking water containing one of the following: (1) reverse osmosis, deionized water; (2) water containing 500 mg/L phenobarbital (PB500); (3) water with purified MC-LR (10 µg/L) added; or (4) water containing lysed Microcystis aeruginosa (lysate; 10 µg/L total MCs). The exposure concentrations were based on environmentally relevant concentrations and previously established Ohio EPA recreational water MC guidelines. Throughout the 30-week exposure, mouse weights, food consumption, and water consumption were not significantly impacted by toxin ingestion. We found no significant differences in the number of gross and histopathologic liver lesion counts across the treatment groups, but we did note that the PB500 group developed lesion densities too numerous to count. Additionally, the proportion of lesions classified as hepatocellular carcinomas in the MC-LR group (44.5%; p < 0.05) and lysate group (55%; p < 0.01) was significantly higher compared to the control group (14.9%). Over the course of the study, the mice ingesting the lysate also had a significantly lower survival probability (64.4%; p < 0.001) compared to water (96.8%), PB500 (95.0%), and MC-LR (95.7%) exposures. Using cyanotoxin levels at common recreational water concentration levels, we demonstrate the cancer-promoting effects of a single cyanotoxin MC congener (MC-LR). Furthermore, we show enhanced hepatocarcinogenesis and significant mortality associated with combinatorial exposure to the multiple MCs and bioactive compounds present in lysed cyanobacterial cells—a scenario representative of the ingestion exposure route, such as HAB-contaminated water and food.
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Affiliation(s)
- Igor Mrdjen
- College of Public Health, Environmental Health Sciences, The Ohio State University, Columbus, OH 43210, USA; (I.M.); (J.L.); (C.M.W.)
| | - Jiyoung Lee
- College of Public Health, Environmental Health Sciences, The Ohio State University, Columbus, OH 43210, USA; (I.M.); (J.L.); (C.M.W.)
- Department of Food Science and Technology, The Ohio State University, Columbus, OH 43210, USA
| | - Christopher M. Weghorst
- College of Public Health, Environmental Health Sciences, The Ohio State University, Columbus, OH 43210, USA; (I.M.); (J.L.); (C.M.W.)
| | - Thomas J. Knobloch
- College of Public Health, Environmental Health Sciences, The Ohio State University, Columbus, OH 43210, USA; (I.M.); (J.L.); (C.M.W.)
- Correspondence:
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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: 3] [Impact Index Per Article: 1.0] [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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Methodological Protocol for Assessing the Environmental Footprint by Means of Ecotoxicological Tools: Wastewater Treatment Plants as an Example Case. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2020. [DOI: 10.1007/978-1-0716-0150-1_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Levin M. The Computational Boundary of a "Self": Developmental Bioelectricity Drives Multicellularity and Scale-Free Cognition. Front Psychol 2019; 10:2688. [PMID: 31920779 PMCID: PMC6923654 DOI: 10.3389/fpsyg.2019.02688] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/14/2019] [Indexed: 12/12/2022] Open
Abstract
All epistemic agents physically consist of parts that must somehow comprise an integrated cognitive self. Biological individuals consist of subunits (organs, cells, and molecular networks) that are themselves complex and competent in their own native contexts. How do coherent biological Individuals result from the activity of smaller sub-agents? To understand the evolution and function of metazoan creatures' bodies and minds, it is essential to conceptually explore the origin of multicellularity and the scaling of the basal cognition of individual cells into a coherent larger organism. In this article, I synthesize ideas in cognitive science, evolutionary biology, and developmental physiology toward a hypothesis about the origin of Individuality: "Scale-Free Cognition." I propose a fundamental definition of an Individual based on the ability to pursue goals at an appropriate level of scale and organization and suggest a formalism for defining and comparing the cognitive capacities of highly diverse types of agents. Any Self is demarcated by a computational surface - the spatio-temporal boundary of events that it can measure, model, and try to affect. This surface sets a functional boundary - a cognitive "light cone" which defines the scale and limits of its cognition. I hypothesize that higher level goal-directed activity and agency, resulting in larger cognitive boundaries, evolve from the primal homeostatic drive of living things to reduce stress - the difference between current conditions and life-optimal conditions. The mechanisms of developmental bioelectricity - the ability of all cells to form electrical networks that process information - suggest a plausible set of gradual evolutionary steps that naturally lead from physiological homeostasis in single cells to memory, prediction, and ultimately complex cognitive agents, via scale-up of the basic drive of infotaxis. Recent data on the molecular mechanisms of pre-neural bioelectricity suggest a model of how increasingly sophisticated cognitive functions emerge smoothly from cell-cell communication used to guide embryogenesis and regeneration. This set of hypotheses provides a novel perspective on numerous phenomena, such as cancer, and makes several unique, testable predictions for interdisciplinary research that have implications not only for evolutionary developmental biology but also for biomedicine and perhaps artificial intelligence and exobiology.
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Affiliation(s)
- Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA, United States
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, United States
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Moore D, Walker SI, Levin M. Cancer as a disorder of patterning information: computational and biophysical perspectives on the cancer problem. CONVERGENT SCIENCE PHYSICAL ONCOLOGY 2017. [DOI: 10.1088/2057-1739/aa8548] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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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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Chernet BT, Fields C, Levin M. Long-range gap junctional signaling controls oncogene-mediated tumorigenesis in Xenopus laevis embryos. Front Physiol 2015; 5:519. [PMID: 25646081 PMCID: PMC4298169 DOI: 10.3389/fphys.2014.00519] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 12/18/2014] [Indexed: 11/21/2022] Open
Abstract
In addition to the immediate microenvironment, long-range signaling may be an important component of cancer. Molecular-genetic analyses have implicated gap junctions-key mediators of cell-cell communication-in carcinogenesis. We recently showed that the resting voltage potential of distant cell groups is a key determinant of metastatic transformation and tumor induction. Here, we show in the Xenopus laevis model that gap junctional communication (GJC) is a modulator of the long-range bioelectric signaling that regulates tumor formation. Genetic disruption of GJC taking place within tumors, within remote host tissues, or between the host and tumors significantly lowers the incidence of tumors induced by KRAS mutations. The most pronounced suppression of tumor incidence was observed upon GJC disruption taking place farther away from oncogene-expressing cells, revealing a role for GJC in distant cells in the control of tumor growth. In contrast, enhanced GJC communication through the overexpression of wild-type connexin Cx26 increased tumor incidence. Our data confirm a role for GJC in tumorigenesis, and reveal that this effect is non-local. Based on these results and on published data on movement of ions through GJs, we present a quantitative model linking the GJC coupling and bioelectrical state of cells to the ability of oncogenes to initiate tumorigenesis. When integrated with data on endogenous bioelectric signaling during left-right patterning, the model predicts differential tumor incidence outcomes depending on the spatial configurations of gap junction paths relative to tumor location and major anatomical body axes. Testing these predictions, we found that the strongest influence of GJ modulation on tumor suppression by hyperpolarization occurred along the embryonic left-right axis. Together, these data reveal new, long-range aspects of cancer control by the host's physiological parameters.
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Affiliation(s)
- Brook T. Chernet
- Department of Biology, Tufts Center for Regenerative and Developmental Biology, Tufts UniversityMedford, MA, USA
| | | | - Michael Levin
- Department of Biology, Tufts Center for Regenerative and Developmental Biology, Tufts UniversityMedford, MA, USA
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Abstract
Understanding the relationship of chemicals to carcinogenesis has progressed significantly since the initial observations of Hill and Pott in the 1700's. Distinguishing between DNA-reactive chemicals and those which increase cancer risk by increasing cell proliferation has been a major breakthrough in delineating overall mechanisms. Competing processes for activation versus inactivation of chemicals occur at many levels, including metabolism, DNA repair, and cellular repair processes. These processes can be affected by other agents to decrease carcinogenesis (chemoprevention). Increasing knowledge of the multiple steps of carcinogenesis is leading to improved methods for screening chemicals for carcinogenic activity and for regulatory decision making. Improvements in assessment of modes of action involved in animal and in vitro models have led to more rational approaches to assessing relevance to humans. The advent of genomics and high-throughput technologies have contributed to investigations of mechanisms and is beginning to impact development of better methods for screening chemicals. Based on developments in basic research, epidemiology, and astute clinical observations, the major risk factors and etiologic agents have been identified for a majority of cancers, which is beginning to lead to methods to decrease cancer incidence overall and identify targets for early detection and treatment.
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Affiliation(s)
- Samuel M Cohen
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-3135, USA.
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Lee CH, Chen IH, Lee CR, Chi CH, Tsai MC, Tsai JL, Lin HF. Inhibition of gap junctional Intercellular communication in WB-F344 rat liver epithelial cells by triphenyltin chloride through MAPK and PI3-kinase pathways. J Occup Med Toxicol 2010; 5:17. [PMID: 20591183 PMCID: PMC2904784 DOI: 10.1186/1745-6673-5-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Accepted: 06/30/2010] [Indexed: 11/10/2022] Open
Abstract
Background Organotin compounds (OTCs) have been widely used as stabilizers in the production of plastic, agricultural pesticides, antifoulant plaints and wood preservation. The toxicity of triphenyltin (TPT) compounds was known for their embryotoxic, neurotoxic, genotoxic and immunotoxic effects in mammals. The carcinogenicity of TPT was not well understood and few studies had discussed the effects of OTCs on gap junctional intercellular communication (GJIC) of cells. Method In the present study, the effects of triphenyltin chloride (TPTC) on GJIC in WB-F344 rat liver epithelial cells were evaluated, using the scrape-loading dye transfer technique. Results TPTC inhibited GJIC after a 30-min exposure in a concentration- and time-dependent manner. Pre-incubation of cells with the protein kinase C (PKC) inhibitor did not modify the response, but the specific MEK 1 inhibitor PD98059 and PI3K inhibitor LY294002 decreased substantially the inhibition of GJIC by TPTC. After WB-F344 cells were exposed to TPTC, phosphorylation of Cx43 increased as seen in Western blot analysis. Conclusions These results show that TPTC inhibits GJIC in WB-F344 rat liver epithelial cells by altering the Cx43 protein expression through both MAPK and PI3-kinase pathways.
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Affiliation(s)
- Chung-Hsun Lee
- Graduate Institute of Occupational Safety and Health, College of Health Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
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Leone A, Zefferino R, Longo C, Leo L, Zacheo G. Supercritical CO(2)-extracted tomato Oleoresins enhance gap junction intercellular communications and recover from mercury chloride inhibition in keratinocytes. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:4769-4778. [PMID: 20235579 DOI: 10.1021/jf1001765] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A nutritionally relevant phytochemical such as lycopene, found in tomatoes and other fruits, has been proposed to have health-promoting effects by modulating hormonal and immune systems, metabolic pathways, and gap junction intercellular communication (GJIC). This work analyzes lycopene extracts, obtained from tomato and tomato added with grape seeds by using a safe and environmentally friendly extraction process, based on supercritical carbon dioxide technology (S-CO(2)). Analysis of the innovative S-CO(2)-extracted oleoresins showed peculiar chemical composition with high lycopene concentration and the presence of other carotenoids, lipids, and phenol compounds. The oleoresins showed a higher in vitro antioxidant activity compared with pure lycopene and beta-carotene and the remarkable ability to enhance the GJIC and to increase cx43 expression in keratinocytes. The oleoresins, (0.9 microM lycopene), were also able to overcome, completely, the GJIC inhibition induced by 10 nM HgCl(2), mercury(II) chloride, suggesting a possible action mechanism.
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Affiliation(s)
- Antonella Leone
- National Research Council, Institute of Science of Food Production (CNR, ISPA), Lecce, Italy.
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Upham BL, Trosko JE. Oxidative-dependent integration of signal transduction with intercellular gap junctional communication in the control of gene expression. Antioxid Redox Signal 2009; 11:297-307. [PMID: 18834329 PMCID: PMC2933147 DOI: 10.1089/ars.2008.2146] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Research on oxidative stress focused primarily on determining how reactive oxygen species (ROS) damage cells by indiscriminate reactions with their macromolecular machinery, particularly lipids, proteins, and DNA. However, many chronic diseases are not always a consequence of tissue necrosis, DNA, or protein damage, but rather to altered gene expression. Gene expression is highly regulated by the coordination of cell signaling systems that maintain tissue homeostasis. Therefore, much research has shifted to the understanding of how ROS reversibly control gene expression through cell signaling mechanisms. However, most research has focused on redox regulation of signal transduction within a cell, but we introduce a more comprehensive-systems biology approach to understanding oxidative signaling that includes gap junctional intercellular communication, which plays a role in coordinating gene expression between cells of a tissue needed to maintain tissue homeostasis. We propose a hypothesis that gap junctions are critical in modulating the levels of second messengers, such as low molecular weight reactive oxygen, needed in the transduction of an external signal to the nucleus in the expression of genes. Thus, any comprehensive-systems biology approach to understanding oxidative signaling must also include gap junctions, in which aberrant gap junctions have been clearly implicated in many human diseases.
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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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Cronier L, Crespin S, Strale PO, Defamie N, Mesnil M. Gap junctions and cancer: new functions for an old story. Antioxid Redox Signal 2009; 11:323-38. [PMID: 18834328 DOI: 10.1089/ars.2008.2153] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cancer was one of the first pathologies to be associated with gap-junction defect. Despite the evidence accumulated over the last 40-year period, the molecular involvement of gap junctions and their structural proteins (connexins) in cancer has not been elucidated. The lack of a satisfying explanation may come from the complexity of the disease, evolving through various stages during tumor progression, with cancer cells exhibiting different phenotypes. Here, the question of the involvement of gap junctions has been readdressed by considering the connexin expression/function level at different fundamental stages of carcinogenesis (cell proliferation, cell invasion, and cancer cell dissemination). By performing this analysis, it becomes clear that gap junctions are probably differently involved, depending on the stage of the cancer progression considered. In particular, the most recent data suggest that connexins may act on cell growth by controlling gene expression through a variety of processes (independent of or dependent on the gap-junctional communication capacity). During invasion, connexins have been demonstrated to enhance adherence of cancer cells to the stroma, migration, and probably their dissemination by establishing communication with the endothelial barrier. All these data present a complex picture of connexins in various functions, depending on the cell phenotype.
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Affiliation(s)
- Laurent Cronier
- Institute of Cellular Physiology and Biology, University of Poitiers/CNRS, Poitiers, France
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Wong RCB, Pera MF, Pébay A. Role of gap junctions in embryonic and somatic stem cells. ACTA ACUST UNITED AC 2009; 4:283-92. [PMID: 18704771 DOI: 10.1007/s12015-008-9038-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Stem cells provide an invaluable tool to develop cell replacement therapies for a range of serious disorders caused by cell damage or degeneration. Much research in the field is focused on the identification of signals that either maintain stem cell pluripotency or direct their differentiation. Understanding how stem cells communicate within their microenvironment is essential to achieve their therapeutic potentials. Gap junctional intercellular communication (GJIC) has been described in embryonic stem cells (ES cells) and various somatic stem cells. GJIC has been implicated in regulating different biological events in many stem cells, including cell proliferation, differentiation and apoptosis. This review summarizes the current understanding of gap junctions in both embryonic and somatic stem cells, as well as their potential role in growth control and cellular differentiation.
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Affiliation(s)
- Raymond C B Wong
- Department of Biological Chemistry, University of California Irvine, Irvine, CA, USA.
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Adhesion, Invasion, Integrins, and Beyond. THE IMPACT OF TUMOR BIOLOGY ON CANCER TREATMENT AND MULTIDISCIPLINARY STRATEGIES 2009. [DOI: 10.1007/978-3-540-74386-6_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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15
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Tai MH, Upham BL, Olson LK, Tsao MS, Reed DN, Trosko JE. Cigarette smoke components inhibited intercellular communication and differentiation in human pancreatic ductal epithelial cells. Int J Cancer 2007; 120:1855-62. [PMID: 17266035 DOI: 10.1002/ijc.22530] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Smoking is a well-documented risk factor for the development of pancreatic adenocarcinoma. Although the most abundant polycyclic aromatic hydrocarbons (PAHs) in cigarette smoke are methylated anthracenes and phenanthrenes, the epigenetic toxicity of these compounds has not been extensively studied. We previously showed that methylanthracenes, which possess a bay-like structure, affect epigenetic events such as an induced release of arachidonic acid, inhibition of gap junctional intercellular communication (GJIC) and induction of mitogen-activated protein kinases in a pluripotent rat liver epithelial stem cell line. Anthracenes with no bay-like structures were inactive. These biological effects are all molecular events associated with the promotional phase of cancer. A human immortalized, nontumorigenic pancreatic ductal epithelial cell line, H6c7, was examined to study the epigenetic toxicity of PAHs related to pancreatic cancer by using scrape-loading dye transfer, immunostaining, RT-PCR and telomerase assay methods. H6c7 cells were GJIC-incompetent and exhibited high telomerase activity when grown in growth factor and hormone-supplemented medium. In the presence of the cAMP elevating drugs (forskolin and IBMX) the cells became GJIC competent and expressed connexins. Telomerase activity was also decreased by cAMP elevating drug treatment. After induction of cAMP, 1-methylanthracene with bay-like structures inhibited GJIC, whereas the 2-methylanthracene lacking a bay-like structure had no effect on GJIC. Telomerase activity remained high in 1-methylanthracene treatment but not with 2-methylanthracene. These results indicate that a prominent component of cigarette smoke, namely methylanthracenes with distinct structural configurations, could be a potential etiological agent contributing to the epigenetic events of pancreatic cancer.
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Affiliation(s)
- Mei-Hui Tai
- Department of Physiology, Michigan State University, East Lansing, MI, USA.
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Yi ZC, Liu YZ, Li HX, Yin Y, Zhuang FY, Fan YB, Wang Z. Tellimagrandin I enhances gap junctional communication and attenuates the tumor phenotype of human cervical carcinoma HeLa cells in vitro. Cancer Lett 2005; 242:77-87. [PMID: 16338066 DOI: 10.1016/j.canlet.2005.10.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2005] [Revised: 10/26/2005] [Accepted: 10/26/2005] [Indexed: 10/25/2022]
Abstract
Tellimagrandin I and chebulinic acid, two hydrolysable tannins, have been shown to exert anti-tumor properties. Dysfunctional gap junctional communication (GJIC) has been recognized as being involved in carcinogenesis. The human cervical carcinoma HeLa cells have been reported to be deficient in functional GJIC. In present study, we investigated whether tellimagrandin I and chebulinic acid might restore functional GJIC in HeLa cells. Both compounds could inhibit the growth of HeLa cells. Either Lucifer yellow transfer assay or calcein transfer assay demonstrated that tellimagrandin I improved GJIC in HeLa cells while chebulinic acid showed no effect on GJIC. The GJIC enhancement by tellimagrandin I occurred along with an increase of Cx43 gene expression at mRNA and protein levels. Exposure to tellimagrandin I also led to inhibition of proliferation and anchorage-independent growth of HeLa cells. In addition, tellimagrandin I decreased the percentage of cells in the G0/G1 and G2/M phases coinciding with an increase in the percentage of cells in the S phase. The accumulation of cells in S phase was coupled with a decreased expression of cyclin A that was critical to the progression of S phase. These results suggested that restoring GJIC might be one explanation for tellimagrandin I antitumor effects, whereas chebulinic acid exerted antitumor action through other pathways.
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Affiliation(s)
- Zong-Chun Yi
- Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China.
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17
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Salameh A, Dhein S. Pharmacology of gap junctions. New pharmacological targets for treatment of arrhythmia, seizure and cancer? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1719:36-58. [PMID: 16216217 DOI: 10.1016/j.bbamem.2005.09.007] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 08/25/2005] [Accepted: 09/06/2005] [Indexed: 11/26/2022]
Abstract
Intercellular communication in many organs is maintained via intercellular gap junction channels composed of connexins, a large protein family with a number of isoforms. This gap junction intercellular communication (GJIC) allows the propagation of action potentials (e.g., in brain, heart), and the transfer of small molecules which may regulate cell growth, differentiation and function. The latter has been shown to be involved in cancer growth: reduced GJIC often is associated with increased tumor growth or with de-differentiation processes. Disturbances of GJIC in the heart can cause arrhythmia, while in brain electrical activity during seizures seems to be propagated via gap junction channels. Many diseases or pathophysiological conditions seem to be associated with alterations of gap junction protein expression. Thus, depending on the target disease opening or closure of gap junctions may be of interest, or alteration of connexin expression. GJIC can be affected acutely by changing gap junction conductance or--more chronic--by altering connexin expression and membrane localisation. This review gives an overview on drugs affecting GJIC.
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Affiliation(s)
- Aida Salameh
- Clinic I for Internal Medicine, Department of Cardiology, University of Leipzig, Johannisallee 32, 04103 Leipzig, Germany.
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Rivedal E, Witz G. Benzene metabolites block gap junction intercellular communication. Role in hematotoxicity and leukemia? Chem Biol Interact 2005; 153-154:257-60. [PMID: 15935824 DOI: 10.1016/j.cbi.2005.03.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A metabolite of benzene, trans,trans-muconaldehyde (MUC) was found to be a strong inhibitor of gap junction intercellular communication (GJIC) with potency similar to that of chlordane. Hydroquinone and the MUC metabolite OH-M-CHO were also strong inhibitors of GJIC. The other MUC metabolites tested, CHO-M-COOH and OH-M-COOH had weak effects on GJIC, while COOH-M-COOH had no effect. Benzene showed no effect on GJIC. The relative potency of the metabolites on GJIC is similar to what is observed with regard to hematotoxic effects. The effect of MUC on GJIC took place in parallel with a strong cellular loss of connexin 43. Substances found to inhibit connexin 43 dependent GJIC have been shown to disrupt normal hematopoietic development. The finding that benzene metabolites interfere with gap junction functionality, and especially the loss of connexin 43 induced by MUC, should be considered concerning the mechanism of benzene-induced hematotoxicity.
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Affiliation(s)
- Edgar Rivedal
- Institute for Cancer Research, Norwegian Radium Hospital, Oslo, Norway.
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Nakamura Y, Trosko JE, Chang CC, Upham BL. Psyllium extracts decreased neoplastic phenotypes induced by the Ha-Ras oncogene transfected into a rat liver oval cell line. Cancer Lett 2004; 203:13-24. [PMID: 14670613 DOI: 10.1016/j.canlet.2003.08.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Inhibition of gap junctional intercellular communication (GJIC) by tumor promoters and oncogenes has been implicated in the removal of initiated cells from the suppression of growth by neighboring cells in the tumor promoting step of carcinogenesis. The GJIC of WB-Ha-ras cell line is GJIC-deficient and they are capable of anchorage independent growth (AIG). The ethanol extract of psyllium increased GJIC 1.65-times and decreased AIG in both number and size of colonies in WB-Ha-ras cells. Histochemical staining of the gap junction protein, connexin43, showed that psyllium restored gap junction plaques on the plasma membrane of the WB-Ha-ras cells. In conclusion, the ethanol extract of psyllium reversed two tumor cell phenotypes, namely reduced GJIC and AIG, induced by the Ha-ras oncogene.
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Affiliation(s)
- Yasushi Nakamura
- Department of Pediatrics and Human Development, National Food Safety and Toxicology Bldg Center, Michigan State University, 243 Food Safety and Toxicology, East Lansing, MI 48824, USA
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Hilscherova K, Blankenship AL, Nie M, Coady KK, Upham BL, Trosko JE, Giesy JP. Oxidative stress in liver and brain of the hatchling chicken (Gallus domesticus) following in ovo injection with TCDD. Comp Biochem Physiol C Toxicol Pharmacol 2003; 136:29-45. [PMID: 14522597 DOI: 10.1016/s1532-0456(03)00167-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was injected into chicken eggs prior to incubation to study possible mechanisms of toxicity and teratogenicity. One of the suggested mechanisms of teratogenicity is oxidative stress. Eggs were injected simultaneously with TCDD and cotreatment compounds in an attempt to prevent oxidative stress or to block cytochrome P450 activity. Indicators of oxidative stress were assessed in livers and brains of hatchling chicks. In ovo, exposure to TCDD caused significant effects on indicators of oxidative stress in liver, but not in the brain of the hatchling chicks. TCDD did not significantly affect superoxide production. In liver, TCDD treatment caused a decrease in glutathione content and glutathione peroxidase activity and an increase in the ratio of oxidized to reduced glutathione. TCDD increased the susceptibility to lipid peroxidation and oxidative DNA damage in liver. Administration of the antioxidants vitamin E and vitamin A provided partial protection against TCDD-induced oxidative stress in liver. The lack of effect of TCDD in chicken brain could be due to the low cytochrome P4501A activity in this tissue and little accumulation of TCDD in brain compared to liver. Phenytoin, a known inducer of oxidative stress, caused a decrease in glutathione content and an increase in susceptibility to lipid peroxidation in both liver and brain and increased oxidative DNA damage in brain. Responsiveness varied among individual animals, but measures of the oxidative stress were correlated.
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Affiliation(s)
- K Hilscherova
- Department of Environmental Chemistry and Ecotoxicology, Faculty of Science, Masaryk University, Brno, Czech Republic
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Upham BL, Suzuki J, Chen G, Wang Y, McCabe LR, Chang CC, Krutovskikh VA, Yamasaki H, Trosko JE. Reduced gap junctional intercellular communication and altered biological effects in mouse osteoblast and rat liver oval cell lines transfected with dominant-negative connexin 43. Mol Carcinog 2003; 37:192-201. [PMID: 12891628 DOI: 10.1002/mc.10137] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Gap junctional intercellular communication (GJIC) maintains normal growth and differentiation of cells in a tissue. The intercellular molecules traversing gap junctions are largely unknown, but the molecular weight (MW) cutoff is normally 1200 Da. No differences in dye transfer were observed in normal or vector controls of WB-F344 rat liver epithelial or mouse osteoblastic MC3T3-E1 cells with either Lucifer Yellow (LY) with a MW of 457 Da (LY-457) or LY with a MW of 649 Da (LY-649). Transfection of a dominant negative-connexin 43 (Cx43) gene decreased GJIC (>50%) when LY-649 was used, however, normal GJIC was observed in both cell lines when LY-457 was used. Therefore, the MW cut off in these clones was considerably less than the wild type. The dominant negative clones of the MC3T3-E1 cells exhibited over 90% less alkaline phosphatase (ALPase) activity and calcium deposition after the induction of differentiation. Similarly, dominant negative Cx43 inhibited gene expression of ALPase and bone sialoprotein but not osteocalcin in MC3T3-E1. WB-F344 cells normally exhibit a biphasic response to 12-O-tetradecanoylphorbol-13-acetate (TPA) where inhibition of GJIC recovers after 2 h, but the dominant negative clones showed no recovery from inhibition of GJIC by TPA. Dominant negative Cx43 also inhibited the formation of network-like structures by WB-F344 cells on Matrigel. These results demonstrate that the dominant negative gene transfected into cell types containing the wild-type connexins result in diminished channel sizes, thus allowing the determination of whether distinct biological endpoints, i.e., differentiation, are dependent upon either small or high MW intercellular signals.
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Affiliation(s)
- Brad L Upham
- National Food Safety & Toxicology Center, and Department of Pediatrics & Human Development, Michigan State University, East Lansing, Michigan 48824, USA
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Abstract
Our previous studies have shown that intercellular communication mediated by gap junctions is impaired in most tumors as well as in cancer cell lines. However, connexin genes that encode gap junction proteins are only rarely mutated in cancer cells. On the other hand, it was reported that mutated Connexin 37 (Cx37) is the origin of shared tumor-associated antigenic octa-peptides (MUT 1 and MUT 2) of two independently derived lung carcinomas 3LL and CMT 64 of mouse origin. Two Cx37 mutations have been implicated: a Cys-54-Gln substitution in FEQNTAQP (MUT 1) and FEQNTAQA (MUT 2); an additional Pro-59-Ala substitution has been proposed in MUT 2. A Cys-54-Gln mutation in both tumors requires three base changes (TGT-to-CAG) to have occurred twice in independently derived tumors. Another complication stems from the fact that Cys 54, which is located in the extra-cellular domain is conserved in all connexins. Due to the important implications that these findings may have regarding the role of gap junctional communication in lung carcinomas as well as in the origin of tumor-associated antigens, we decided to re-examine these mutations. Thus, we PCR-amplified genomic DNA from 3LL and CMT and sequenced the coding region of Cx37 encompassing codon 54. We then analyzed the PCR products by digestion with the restriction enzyme MaeIII, to discern the presence of the putative mutation. Here we have unambiguously demonstrated that clones K(b)39.5 (39.5) and D122 of 3LL, and C6 and E9 of CMT 64, previously employed, have only normal Cx37 sequences, including those of codon 54. Therefore, we concluded that Cx37 is not mutated in 3LL and CMT 64 carcinomas.
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MESH Headings
- Amino Acid Substitution
- Animals
- Carcinoma/genetics
- Carcinoma/pathology
- Carcinoma, Lewis Lung/genetics
- Carcinoma, Lewis Lung/pathology
- Clone Cells/transplantation
- Codon/genetics
- Connexins/genetics
- DNA Mutational Analysis
- DNA, Neoplasm/genetics
- Gap Junctions/physiology
- Lung Neoplasms/genetics
- Lung Neoplasms/pathology
- Lymphoma/genetics
- Lymphoma/pathology
- Lymphoma, T-Cell/genetics
- Lymphoma, T-Cell/pathology
- Mice
- Mice, Inbred C57BL
- Mutation, Missense
- Neoplasm Proteins/genetics
- Neoplasm Transplantation
- Polymerase Chain Reaction
- Polymorphism, Restriction Fragment Length
- Protein Structure, Tertiary
- Sequence Analysis, DNA
- Tumor Cells, Cultured/transplantation
- Gap Junction alpha-4 Protein
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Affiliation(s)
- Gideon Berke
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
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Carruba G, Stefano R, Cocciadiferro L, Saladino F, Di Cristina A, Tokar E, Quader STA, Webber MM, Castagnetta L. Intercellular communication and human prostate carcinogenesis. Ann N Y Acad Sci 2002; 963:156-68. [PMID: 12095941 DOI: 10.1111/j.1749-6632.2002.tb04107.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Gap-junction-mediated intercellular communication (GJIC) is required for completion of embryonic development, tissue homeostasis, and regulation of cell proliferation and death. Although, as emphasized in several reports, defects or disruption of GJIC may be important in carcinogenesis, the potential role of GJIC in the onset and progression of human prostate cancer remains ill-defined. The gap junction channel-forming connexins (Cx) comprise a multigene family of highly conserved proteins that are differentially expressed in a tissue- and development-specific manner; changes in connexin expression are also commonly seen during cellular differentiation. However, when multiple connexins are concurrently expressed, gap junction channels may consist of more than one connexin species. This is important, because only certain pairings give rise to functional channels. In our studies, we investigated GJIC in a panel of both nontumorigenic (RWPE-1) and malignant (RWPE-2, LNCaP, DU-145) human prostate epithelial cells, compared to a normal rat liver epithelial F344 (WB-1) cell line, as it was found to be junctionally proficient. In addition, expression and regulation of Cx43 and Cx32 were also inspected using western blot analysis. The ability of hormones, antihormones, and the antihypertensive drug forskolin to restore GJIC in nontumorigenic and malignant human prostate epithelial cells was examined by the scrape-loading/dye transfer (SL/DT) or fluorescence recovery after photobleaching (FRAP) methods using an Ultima laser cytometer. Results from both assays showed that neither nontumorigenic nor malignant prostate cells have functional GJIC. However, both estrone (E1) and forskolin (FK) induced a significant increase (4.4- and 2.8-fold, respectively) in cell-cell communication only in the RWPE-1 cells. Interestingly, the use of Matrigel, a solubilized basement membrane, as substrate for cell attachment and growth resulted in the rescue of GJIC activity in RWPE-1 cells, as revealed by the SL/DT method. Furthermore, E1 induced a twofold increase in connexin 43 (Cx43), whereas forskolin caused a 50% reduction in Cx32 expression in RWPE-1 cells. These data suggest that agents that increase Cx43:Cx32 ratio may restore GJIC in junctionally deficient cells, providing a basis for the development of new strategies for the prevention and treatment of human prostate cancer.
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Affiliation(s)
- Giuseppe Carruba
- Department of Experimental Oncology and Clinical Application, University Medical School, Palermo, Italy.
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Huang R, Liu YG, Lin Y, Fan Y, Boynton A, Yang D, Huang RP. Enhanced apoptosis under low serum conditions in human glioblastoma cells by connexin 43 (Cx43). Mol Carcinog 2001; 32:128-38. [PMID: 11746825 DOI: 10.1002/mc.1072] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Connexin 43 (Cx43), a structural component of gap junctions, is believed to function as a tumor suppressor gene. Previously, we showed that expression of Cx43 suppresses cell proliferation and tumorigenicity of human glioblastoma cells [Huang et al., Cancer Res 58:5089-5096, 1998] and enhances apoptosis in response to chemotherapeutic agents [Huang et al., Int J Cancer 92:130-138, 2001]. In the present study, we demonstrated that expression of Cx43 in human glioblastoma cells potentiated an apoptotic program under low-serum conditions. The Cx43-mediated effect was coupled with a decreased expression of the specific apoptosis-inhibitor bcl-2. Overexpression of bcl-2 in Cx43-transfected cells conferred resistance to apoptosis induced under low-serum conditions, suggesting that the Cx43-mediated apoptosis under low-serum conditions is regulated, in part, through the downregulation of bcl-2 expression. Furthermore, application of the phosphatidylinositol-3'-OH kinase inhibitor LY294002 specifically induced apoptosis in Cx43-transfected cells. Our results demonstrate a new role of Cx43 in the mediation of apoptosis under low serum conditions.
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Affiliation(s)
- R Huang
- Division of Research, Department of Gynecology and Obstetrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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