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Shimamura Y, Yui T, Horiike H, Masuda S. Toxicity of combined exposure to acrylamide and Staphylococcus aureus. Toxicol Rep 2022; 9:876-882. [DOI: 10.1016/j.toxrep.2022.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 04/17/2022] [Accepted: 04/18/2022] [Indexed: 11/26/2022] Open
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Jabeen M, Fayyaz M, Irudayaraj J. Epigenetic Modifications, and Alterations in Cell Cycle and Apoptosis Pathway in A549 Lung Carcinoma Cell Line upon Exposure to Perfluoroalkyl Substances. TOXICS 2020; 8:toxics8040112. [PMID: 33238432 PMCID: PMC7711517 DOI: 10.3390/toxics8040112] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 11/09/2020] [Accepted: 11/20/2020] [Indexed: 02/06/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a group of human-made compounds with strong C-F bonds, and have been used in various manufacturing industries for decades. PFAS have been reported to deleterious effect on human health, which has led to studies identifying the possible toxicity and toxicity routes of these compounds. We report that these compounds have the potential to cause epigenetic modifications, and to induce dysregulation in the cell proliferation cycle as well as apoptosis in A549 lung cancer cells when exposed to 10-, 200- and 400 μM concentrations of each compound. Our studies show that exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) may cause hypomethylation in the epigenome, but changes in the epigenetic makeup are not evident upon exposure to GenX. We establish that exposure to lower doses of these compounds causes the cells' balance to shift to cell proliferation, whereas exposure to higher concentrations shifts the balance more towards apoptosis. Furthermore, the apoptosis pathway upon exposure to GenX, PFOA, and PFOS has also been identified. Our findings suggest that exposure to any of these compounds may have profound effects in patients with pre-existing lung conditions or could trigger lung cancinogenesis.
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Affiliation(s)
- Musarrat Jabeen
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; (M.J.); (M.F.)
- Biomedical Research Centre (BRC) at Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL 61801, USA
- Cancer Centre at Illinois (CCIL), University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Muhammad Fayyaz
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; (M.J.); (M.F.)
- Biomedical Research Centre (BRC) at Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL 61801, USA
- Cancer Centre at Illinois (CCIL), University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Joseph Irudayaraj
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; (M.J.); (M.F.)
- Biomedical Research Centre (BRC) at Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL 61801, USA
- Cancer Centre at Illinois (CCIL), University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Nick Holonyak Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carl R. Woese Institute of Genomic Biology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
- Correspondence: ; Tel.: +217-300-0525
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Lin TC, Wang KH, Chuang KH, Kao AP, Kuo TC. Downregulation of gap junctional intercellular communication and connexin 43 expression by bisphenol A in human granulosa cells. Biotechnol Appl Biochem 2020; 68:676-682. [PMID: 32610363 DOI: 10.1002/bab.1979] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022]
Abstract
Gap junctional intercellular communication (GJIC) is the transfer of ions, metabolites, and second messengers between neighboring cells through intercellular junctions. Connexin 43 (Cx43) was found to be the type of gap junction protein responsible for human granulosa cells (GCs) and oocyte communication, which is required for folliculogenesis and oocyte maturation. Bisphenol A (BPA), an estrogenic-like endocrine-disrupting chemical, is one of the most widely produced chemicals around the world. There are reports that the chemical might cause endometrial tumorigenesis and several female reproductive disorders. This study demonstrated that cell culture medium, containing antioxidants (N-acetyl-l-cysteine and l-ascorbic acid-2-phosphate), was able to enhance the survival and self-renewal of GCs. In addition, we found that BPA at environmentally relevant concentration (10-7 M) reduced Cx43 expression and GJIC in GCs through estrogen receptor and mitogen-activated protein kinase pathways. The results of this study not only reveal the reproductive toxicity of BPA but also provide possible mechanisms by which BPA inhibited GJIC in GCs.
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Affiliation(s)
- Ta-Chin Lin
- Department of Obstetrics and Gynecology, Kuo General Hospital, Tainan, Taiwan.,Center for Reproductive Medicine, Kuo General Hospital, Tainan, Taiwan
| | - Kai-Hung Wang
- Department of Obstetrics and Gynecology, Kuo General Hospital, Tainan, Taiwan.,Center for Reproductive Medicine, Kuo General Hospital, Tainan, Taiwan.,Department of Laboratory Medicine, Kuo General Hospital, Tainan, Taiwan
| | - Kuo-Hsiang Chuang
- Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan
| | - An-Pei Kao
- Stemforce Biotechnology Co., Ltd, Chiayi, Taiwan
| | - Tsung-Cheng Kuo
- Department of Obstetrics and Gynecology, Kuo General Hospital, Tainan, Taiwan.,Center for Reproductive Medicine, Kuo General Hospital, Tainan, Taiwan
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Yeo JH, Choi EJ, Lee J. Inhibition of gap junctional intercellular communication by an anti-migraine agent, flunarizine. PLoS One 2019; 14:e0222326. [PMID: 31513635 PMCID: PMC6742374 DOI: 10.1371/journal.pone.0222326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 08/27/2019] [Indexed: 02/08/2023] Open
Abstract
Gap junctions (GJs), which consist of proteins called connexins, are intercellular channels that allow the passage of ions, second messengers, and small molecules. GJs and connexins are considered as emerging therapeutic targets for various diseases. Previously, we screened numerous compounds using our recently developed iodide yellow fluorescent protein gap junctional intercellular communication (I-YFP GJIC) assay and found that flunarizine (FNZ), used for migraine prophylaxis and as an add-on therapy for epilepsy, inhibits GJIC in LN215 human glioma cells. In this study, we confirmed that FNZ inhibits GJIC using the I-YFP GJIC assay. We demonstrated that FNZ inhibits GJ activities via a mechanism that is independent of calcium channels and dopaminergic D2, histaminergic H1, or 5-HT receptors. In addition, we showed that FNZ significantly increases connexin 43 (Cx43) phosphorylation on the cell surface, but does not alter the total amount of Cx43. The beneficial effects of FNZ on migraines and epilepsy might be related to GJ inhibition.
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Affiliation(s)
- Joo Hye Yeo
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Songdogwahak-ro, Yeonsu-gu, Korea
| | - Eun Ju Choi
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Songdogwahak-ro, Yeonsu-gu, Korea
| | - Jinu Lee
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Songdogwahak-ro, Yeonsu-gu, Korea
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Fan FY, Sang LX, Jiang M. Catechins and Their Therapeutic Benefits to Inflammatory Bowel Disease. Molecules 2017; 22:E484. [PMID: 28335502 PMCID: PMC6155401 DOI: 10.3390/molecules22030484] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 02/19/2017] [Accepted: 02/28/2017] [Indexed: 02/07/2023] Open
Abstract
Catechins are natural polyphenolic phytochemicals that exist in food and medicinal plants, such as tea, legume and rubiaceae. An increasing number of studies have associated the intake of catechins-rich foods with the prevention and treatment of chronic diseases in humans, such as inflammatory bowel disease (IBD). Some studies have demonstrated that catechins could significantly inhibit the excessive oxidative stress through direct or indirect antioxidant effects and promote the activation of the antioxidative substances such as glutathione peroxidases (GPO) and glutathione (GSH), reducing the oxidative damages to the colon. In addition, catechins can also regulate the infiltration and proliferation of immune related-cells, such as neutrophils, colonic epithelial cells, macrophages, and T lymphocytes, helping reduce the inflammatory relations and provide benefits to IBD. Perhaps catechins can further inhibit the deterioration of intestinal lesions through regulating the cell gap junctions. Furthermore, catechins can exert their significant anti-inflammatory properties by regulating the activation or deactivation of inflammation-related oxidative stress-related cell signaling pathways, such as nuclear factor-kappa B (NF-κB), mitogen activated protein kinases (MAPKs), transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2), signal transducer and the activator of transcription 1/3 (STAT1/3) pathways. Finally, catechins can also stabilize the structure of the gastrointestinal micro-ecological environment via promoting the proliferation of beneficial intestinal bacteria and regulating the balance of intestinal flora, so as to relieve the IBD. Furthermore, catechins may regulate the tight junctions (TJ) in the epithelium. This paper elaborates the currently known possible molecular mechanisms of catechins in favor of IBD.
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Affiliation(s)
- Fei-Yan Fan
- Department of Gastroenterology, First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang 110001, China.
| | - Li-Xuan Sang
- Department of Geriatrics, First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang 110001, China.
| | - Min Jiang
- Department of Gastroenterology, First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang 110001, China.
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Trosko JE, Lenz HJ. What roles do colon stem cells and gap junctions play in the left and right location of origin of colorectal cancers? J Cell Commun Signal 2017; 11:79-87. [PMID: 28220297 PMCID: PMC5362582 DOI: 10.1007/s12079-017-0381-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/02/2017] [Indexed: 12/15/2022] Open
Abstract
This "Commentary" examines an important clinical observation that right-sided colorectal cancers appear less treatable than the left-sided cancers. The concepts of (a) the "initiation/promotion/progression" process, (b) the stem cell hypothesis, (c) the role gap junctional intercellular communication, (d) cancer cells lacking GJIC either because of the non-expression of connexin genes or of non-functional gap junction proteins, and (e) the role of the microbiome in promoting initiated colon stem cells to divide symmetrically or asymmetrically are examined to find an explanation. It has been speculated that "embryonic-like" lesions in the ascending colon are initiated stem cells, promoted via symmetrical cell division, while the polyp-type lesions in the descending colon are initiated stem cells stimulated to divide asymmetrically. To test this hypothesis, experiments could be designed to examine if right-sided lesions might express Oct4A and ABCG2 genes but not any connexin genes, whereas the left-sided lesions might express a connexin gene, but not Oct4A or the ABCG2 genes. Treatment of the right sided lesions might include transcriptional regulators, whereas the left-sided lesions would need to restore the posttranslational status of the connexin proteins.
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Affiliation(s)
- James E Trosko
- Department Pediatrics and Human Development, College of Human Medicine, Michigan State University, 1129 Farm Lane, East Lansing, MI, 48824, USA.
| | - Heinz-Josef Lenz
- University of California Norris Comprehensive Cancer Center, Los Angeles, CA, USA
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Tsuda S. Differential toxicity between perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). J Toxicol Sci 2016; 41:SP27-SP36. [PMID: 28003637 DOI: 10.2131/jts.41.sp27] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Perfluoroalkyl substances (PFASs) are persistent environmental contaminants. Perfluorooctane sulfonate (PFOS) and Perfluorooctanoic acid (PFOA) are representatives of PFASs. Recently, the U.S. Environmental Protection Agency (US EPA) set the health advisory level as 70 parts per trillion for lifetime exposure to PFOS and PFOA from drinking water, based on the EPA's 2016 Health Effects Support Documents. Then, a monograph on PFOA was made available online by the International Agency for Research on Cancer, where the agency classified PFOA as "possibly carcinogenic to humans" (Group 2B). The distinction between PFOS and PFOA, however, may not be easily understood from the above documents. This paper discussed differential toxicity between PFOS and PFOA focusing on neurotoxicity, developmental toxicity and carcinogenicity, mainly based on these documents. The conclusions are as follows: Further mechanistic studies may be necessary for ultrasonic-induced PFOS-specific neurotoxicity. To support the hypothesis for PFOS-specific neonatal death that PFOS interacts directly with components of natural lung surfactant, in vivo studies to relate the physicochemical effects to lung collapse may be required. PFOA-induced DNA damage secondary to oxidative stress may develop to mutagenicity under the condition where PFOA-induced apoptosis is not sufficient to remove the damaged cells. A study to find whether PFOA induces apoptosis in normal human cells may contribute to assessment of human carcinogenicity. Studies for new targets such as hepatocyte nuclear factor 4α (HNF4α) may help clarify the underlying mechanism for PFOA-induced carcinogenicity.
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Affiliation(s)
- Shuji Tsuda
- Iwate Institute of Environmental Health Sciences
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Nath Roy D, Goswami R, Pal A. Nanomaterial and toxicity: what can proteomics tell us about the nanotoxicology? Xenobiotica 2016; 47:632-643. [PMID: 27414072 DOI: 10.1080/00498254.2016.1205762] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
1. In the last few years, a substantial scientific work is focused to identify the potential toxicity of nanomaterials by studying the cellular pathways under in vitro and in vivo conditions. Owing to high surface area to volume ratio nanoparticles (NPs) can pass through cell membranes which might be responsible for creating adverse interactions in biological systems. Simultaneously, researchers are also interested to assess the fate of NP inside the living system, which may lead to altered protein expression as well as protein corona formation. 2. According to published reports, NP-mediated toxicity involves altered cellular system including cell morphology, cell differentiation, cell metabolism, cell mobility, cellular immunity, which is derived from the side effects of nanoformulation and leading to apoptosis and necrosis. These results indicate the existence of potential toxic effect of these particles to human health. 3. The advent of proteomics with sophisticated technical improvement coupled with advanced bioinformatics has led to identify altered proteins due to nanomaterial exposure that could provide a new avenue to biomarker discovery. 4. This review aims to provide the current status of safe production and use of nanomaterials.
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Affiliation(s)
- Dijendra Nath Roy
- a Department of Bioengineering , National Institute of Technology , Agartala , Tripura , India
| | - Ritobrata Goswami
- b Division of Biological & Life Sciences , School of Arts & Sciences, Ahmedabad University , Ahmedabad , Gujarat , India , and
| | - Ayantika Pal
- c Department of Human Physiology , Tripura University , Suryamaninagar , Tripura , India
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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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Khan S, Shukla S, Sinha S, Meeran SM. Epigenetic targets in cancer and aging: dietary and therapeutic interventions. Expert Opin Ther Targets 2016; 20:689-703. [PMID: 26667209 DOI: 10.1517/14728222.2016.1132702] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Epigenetic regulation plays a critical role in normal growth and embryonic development by controlling the transcriptional activities of several genes. A growing number of epigenetic changes have been reported in the regulation of key genes involved in cancer and aging. Drugs with epigenetic modulatory activities, mainly histone deacetylase and DNA methyltransferase inhibitors, have received wider attention in aging and cancer research. AREAS COVERED In this review, we summarize the major epigenetic alterations in cancer and aging, with special emphasis on possible therapeutic targets and interventions by dietary as well as bioactive phytochemicals. EXPERT OPINION Some epigenetic-targeting drugs have received FDA approval and many others are undergoing different phases of clinical trials for cancer therapy. In addition to the synthetic compounds, several bioactive phytochemicals and dietary interventions, such as caloric restriction, have been shown to possess epigenetic modulatory activities in multiple cancers. These epigenetic modulators have been shown to delay aging and minimize the risk of cancer both in preclinical as well as clinical models. Therefore, knowledge of bioactive phytochemicals along with dietary interventions can be utilized for cancer prevention and therapy both alone and with existing drugs to achieve optimum efficacy.
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Affiliation(s)
- Sajid Khan
- a Division of Endocrinology , CSIR-Central Drug Research Institute , Lucknow , India
| | - Samriddhi Shukla
- a Division of Endocrinology , CSIR-Central Drug Research Institute , Lucknow , India
| | - Sonam Sinha
- a Division of Endocrinology , CSIR-Central Drug Research Institute , Lucknow , India
| | - Syed Musthapa Meeran
- a Division of Endocrinology , CSIR-Central Drug Research Institute , Lucknow , India
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Persano L, Zagoura D, Louisse J, Pistollato F. Role of Environmental Chemicals, Processed Food Derivatives, and Nutrients in the Induction of Carcinogenesis. Stem Cells Dev 2015; 24:2337-52. [DOI: 10.1089/scd.2015.0081] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Luca Persano
- Istituto di Riceca Pediatrica Città della Speranza—IRP, Padova, Italy
- Department of Woman and Child Health, University of Padova, Padova, Italy
| | - Dimitra Zagoura
- Laboratory of Biology, University of Athens School of Medicine, Athens, Greece
| | - Jochem Louisse
- Division of Toxicology, Wageningen University, Wageningen, the Netherlands
| | - Francesca Pistollato
- Center for Nutrition & Health, Universidad Europea del Atlantico (UEA), Santander, Spain
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Cheng CY. Toxicants target cell junctions in the testis: Insights from the indazole-carboxylic acid model. SPERMATOGENESIS 2015; 4:e981485. [PMID: 26413399 PMCID: PMC4581065 DOI: 10.4161/21565562.2014.981485] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 10/23/2014] [Indexed: 12/31/2022]
Abstract
There are numerous types of junctions in the seminiferous epithelium which are integrated with, and critically dependent on the Sertoli cell cytoskeleton. These include the basal tight junctions between Sertoli cells that form the main component of the blood–testis barrier, the basal ectoplasmic specializations (basal ES) and basal tubulobulbar complexes (basal TBC) between Sertoli cells; as well as apical ES and apical TBC between Sertoli cells and the developing spermatids that orchestrate spermiogenesis and spermiation. These junctions, namely TJ, ES, and TBC interact with actin microfilament-based cytoskeleton, which together with the desmosomal junctions that interact with the intermediate filament-based cytoskeleton plus the highly polarized microtubule-based cytoskeleton are working in concert to move spermatocytes and spermatids between the basal and luminal aspect of the seminiferous epithelium. In short, these various junctions are structurally complexed with the actin- and microtubule-based cytoskeleton or intermediate filaments of the Sertoli cell. Studies have shown toxicants (e.g., cadmium, bisphenol A (BPA), perfluorooctanesulfonate (PFOS), phthalates, and glycerol), and some male contraceptives under development (e.g., adjudin, gamendazole), exert their effects, at least in part, by targeting cell junctions in the testis. The disruption of Sertoli–Sertoli cell and Sertoli–germ cell junctions, results in the loss of germ cells from the seminiferous epithelium. Adjudin, a potential male contraceptive under investigation in our laboratory, produces loss of spermatids from the seminiferous tubules through disruption of the Sertoli cell spermatid junctions and disruption of the Sertoli cell cytoskeleton. The molecular and structural changes associated with adjudin administration are described, to provide an example of the profile of changes caused by disturbance of Sertoli-germ cell and also Sertoli cell-cell junctions.
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Affiliation(s)
- C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research; Center for Biomedical Research; Population Council ; New York, NY USA
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Ascenso A, Ribeiro H, Marques HC, Oliveira H, Santos C, Simões S. Chemoprevention of photocarcinogenesis by lycopene. Exp Dermatol 2014; 23:874-8. [DOI: 10.1111/exd.12491] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2014] [Indexed: 12/30/2022]
Affiliation(s)
- Andreia Ascenso
- Instituto de Investigação do Medicamento (iMed.ULisboa); Faculdade de Farmácia; Universidade de Lisboa; Lisboa Portugal
| | - Helena Ribeiro
- Instituto de Investigação do Medicamento (iMed.ULisboa); Faculdade de Farmácia; Universidade de Lisboa; Lisboa Portugal
| | - Helena C. Marques
- Instituto de Investigação do Medicamento (iMed.ULisboa); Faculdade de Farmácia; Universidade de Lisboa; Lisboa Portugal
| | - Helena Oliveira
- Departamento de Biologia; Laboratório de Biotecnologia e Citómica; CESAM; Universidade de Aveiro; Aveiro Portugal
| | - Conceição Santos
- Departamento de Biologia; Laboratório de Biotecnologia e Citómica; CESAM; Universidade de Aveiro; Aveiro Portugal
| | - Sandra Simões
- Instituto de Investigação do Medicamento (iMed.ULisboa); Faculdade de Farmácia; Universidade de Lisboa; Lisboa Portugal
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Trosko JE. Human adult stem cells as the target cells for the initiation of carcinogenesis and for the generation of "cancer stem cells". Int J Stem Cells 2014; 1:8-26. [PMID: 24855504 DOI: 10.15283/ijsc.2008.1.1.8] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2008] [Indexed: 01/12/2023] Open
Abstract
The inference to stem cells has been found in ancient myths and the concept of stem cells has existed in the fields of plant biology, developmental biology and embryology for decades. In the field of cancer research, the stem cell theory was one of the earliest hypotheses on the origin of a cancer from a single cell. However, an opposing hypothesis had it that an adult differentiated somatic cell could "de-differentiate" to become a cancer cell. Only within the last decade, via the "cloning" of Dolly, the sheep, did the field of stem cell biology really trigger an exciting revolution in biological research. The isolation of human embryonic stem cells has created a true revolution in the life sciences that has led to the hope that these human stem cells could lead to (a) basic science understanding of gene regulation during differentiation and development; (b) stem cell therapy; (c) gene therapy via stem cells; (d) the use of stem cells for drug discovery; (e) screening for toxic effects of chemicals; and (f) understand the aging and diseases of aging processes.
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Affiliation(s)
- James E Trosko
- Department of Pediatrics/Human Development, College of Human Medicine, Michigan State University, East Lansing, Michigan 48824, USA
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15
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Muehsam D, Ventura C. Life rhythm as a symphony of oscillatory patterns: electromagnetic energy and sound vibration modulates gene expression for biological signaling and healing. Glob Adv Health Med 2014; 3:40-55. [PMID: 24808981 PMCID: PMC4010966 DOI: 10.7453/gahmj.2014.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- David Muehsam
- Visual Institute of Developmental Sciences, Bologna, Italy (Dr Muehsam)
| | - Carlo Ventura
- National Institute of Biostructures and Biosystems, Visual Institute of Developmental Sciences, Bologna; Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna (Dr Ventura), Italy
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Antiproliferative Action of Conjugated Linoleic Acid on Human MCF-7 Breast Cancer Cells Mediated by Enhancement of Gap Junctional Intercellular Communication through Inactivation of NF- κ B. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:429393. [PMID: 24371460 PMCID: PMC3858871 DOI: 10.1155/2013/429393] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 11/01/2013] [Indexed: 12/18/2022]
Abstract
The major conjugated linoleic acid (CLA) isomers, c9,t11-CLA and t10,c12-CLA, have anticancer effects; however, the exact mechanisms underlying these effects are unknown. Evidence suggests that reversal of reduced gap junctional intercellular communication (GJIC) in cancer cells inhibits cell growth and induces cell death. Hence, we determined that CLA isomers enhance GJIC in human MCF-7 breast cancer cells and investigated the underlying molecular mechanisms. The CLA isomers significantly enhanced GJIC of MCF-7 cells at 40 μM concentration, whereas CLA inhibited cell growth and induced caspase-dependent apoptosis. CLA increased connexin43 (Cx43) expression both at the transcriptional and translational levels. CLA inhibited nuclear factor-κB (NF-κB) activity and enhanced reactive oxygen species (ROS) generation. No significant difference was observed in the efficacy of c9,t11-CLA and t10,c12-CLA. These results suggest that the anticancer effect of CLA is associated with upregulation of GJIC mediated by enhanced Cx43 expression through inactivation of NF-κB and generation of ROS in MCF-7 cells.
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Stoccoro A, Karlsson HL, Coppedè F, Migliore L. Epigenetic effects of nano-sized materials. Toxicology 2013; 313:3-14. [DOI: 10.1016/j.tox.2012.12.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 11/12/2012] [Accepted: 12/03/2012] [Indexed: 12/17/2022]
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Eroglu A, Harrison EH. Carotenoid metabolism in mammals, including man: formation, occurrence, and function of apocarotenoids. J Lipid Res 2013; 54:1719-30. [PMID: 23667178 PMCID: PMC3679377 DOI: 10.1194/jlr.r039537] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Indexed: 12/22/2022] Open
Abstract
Vitamin A was recognized as an essential nutrient 100 years ago. In the 1930s, it became clear that dietary β-carotene was cleaved at its central double to yield vitamin A (retinal or β-apo-15'-carotenal). Thus a great deal of research has focused on the central cleavage of provitamin A carotenoids to form vitamin A (retinoids). The mechanisms of formation and the physiological role(s) of noncentral (eccentric) cleavage of both provitamin A carotenoids and nonprovitamin A carotenoids has been less clear. It is becoming apparent that the apocarotenoids exert unique biological activities themselves. These compounds are found in the diet and thus may be absorbed in the intestine, or they may form from enzymatic or nonenzymatic cleavage of the parent carotenoids. The mechanism of action of apocarotenoids in mammals is not fully worked out. However, as detailed in this review, they have profound effects on gene expression and work, at least in part, through the modulation of ligand-activated nuclear receptors. Understanding the interactions of apocarotenoids with other lipid-binding proteins, chaperones, and metabolizing enzymes will undoubtedly increase our understanding of the biological roles of these carotenoid metabolites.
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Affiliation(s)
| | - Earl H. Harrison
- Department of Human Nutrition, Ohio State University, Columbus, OH
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Leone A, Lecci RM, Durante M, Piraino S. Extract from the zooxanthellate jellyfish Cotylorhiza tuberculata modulates gap junction intercellular communication in human cell cultures. Mar Drugs 2013; 11:1728-62. [PMID: 23697954 PMCID: PMC3707171 DOI: 10.3390/md11051728] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 04/24/2013] [Accepted: 04/25/2013] [Indexed: 12/13/2022] Open
Abstract
On a global scale, jellyfish populations in coastal marine ecosystems exhibit increasing trends of abundance. High-density outbreaks may directly or indirectly affect human economical and recreational activities, as well as public health. As the interest in biology of marine jellyfish grows, a number of jellyfish metabolites with healthy potential, such as anticancer or antioxidant activities, is increasingly reported. In this study, the Mediterranean “fried egg jellyfish” Cotylorhiza tuberculata (Macri, 1778) has been targeted in the search forputative valuable bioactive compounds. A medusa extract was obtained, fractionated, characterized by HPLC, GC-MS and SDS-PAGE and assayed for its biological activity on breast cancer cells (MCF-7) and human epidermal keratinocytes (HEKa). The composition of the jellyfish extract included photosynthetic pigments, valuable ω-3 and ω-6 fatty acids, and polypeptides derived either from jellyfish tissues and their algal symbionts. Extract fractions showed antioxidant activity and the ability to affect cell viability and intercellular communication mediated by gap junctions (GJIC) differentially in MCF-7and HEKa cells. A significantly higher cytotoxicity and GJIC enhancement in MCF-7 compared to HEKa cells was recorded. A putative action mechanism for the anticancer bioactivity through the modulation of GJIC has been hypothesized and its nutraceutical and pharmaceutical potential was discussed.
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Affiliation(s)
- Antonella Leone
- Institute of Sciences of Food Production, National Research Council, Unit of Lecce (CNR, ISPA), Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mails: (R.M.L.); (M.D.)
- CoNISMa, National Interuniversity Consortium on Marine Sciences, Local Unit of Lecce, Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +39-0832-422-615; Fax: +39-0832-422-620
| | - Raffaella Marina Lecci
- Institute of Sciences of Food Production, National Research Council, Unit of Lecce (CNR, ISPA), Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mails: (R.M.L.); (M.D.)
- CoNISMa, National Interuniversity Consortium on Marine Sciences, Local Unit of Lecce, Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mail:
| | - Miriana Durante
- Institute of Sciences of Food Production, National Research Council, Unit of Lecce (CNR, ISPA), Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mails: (R.M.L.); (M.D.)
| | - Stefano Piraino
- CoNISMa, National Interuniversity Consortium on Marine Sciences, Local Unit of Lecce, Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mail:
- University of Salento, Via Prov.le Lecce-Monteroni, Lecce 73100, Italy
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20
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Pointis G, Gilleron J, Carette D, Segretain D. Testicular connexin 43, a precocious molecular target for the effect of environmental toxicants on male fertility. SPERMATOGENESIS 2011; 1:303-317. [PMID: 22332114 DOI: 10.4161/spmg.1.4.18392] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 10/10/2011] [Accepted: 10/10/2011] [Indexed: 02/08/2023]
Abstract
Many recent epidemiological, clinical and experimental findings support the hypothesis that environmental toxicants are responsible for the increasing male reproductive disorders (congenital malformations, declining sperm counts and testicular cancer) over the past 20 years. It has also been reported that exposure to these toxicants, during critical periods of development (fetal and neonatal), represents a more considerable risk for animals and humans than exposure during adulthood. However, the molecular targets for these chemicals have not been clearly identified. Recent studies showed that a family of transmembranous proteins, named connexins, regulates numerous physiological processes involved in testicular development and function, such as Sertoli and germ cell proliferation, differentiation, germ cell migration and apoptosis. In the testis, knockout strategy revealed that connexin 43, the predominant connexin in this organ, is essential for spermatogenesis. In addition, there is evidence that many environmental toxicants could alter testicular connexin 43 by dysregulation of numerous mechanisms controlling its function. In the present work, we propose first to give an overview of connexin expression and intercellular gap junction coupling in the developing fetal and neonatal testes. Second, we underline the impact of maternally chemical exposure on connexin 43 expression in the perinatal developing testis. Lastly, we attempt to link this precocious effect to male offspring fertility.
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21
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Marin-Kuan M, Ehrlich V, Delatour T, Cavin C, Schilter B. Evidence for a role of oxidative stress in the carcinogenicity of ochratoxin a. J Toxicol 2011; 2011:645361. [PMID: 21776264 PMCID: PMC3135259 DOI: 10.1155/2011/645361] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 04/20/2011] [Indexed: 12/15/2022] Open
Abstract
The in vitro and in vivo evidence compatible with a role for oxidative stress in OTA carcinogenicity has been collected and described. Several potential oxido-reduction mechanisms have been identified in the past. More recently, the possibility of a reduction of cellular antioxidant defense has been raised as an indirect source of oxidative stress. Consequences resulting from the production of oxidative stress are observed at different levels. First, OTA exposure has been associated with increased levels of oxidative DNA, lipid, and protein damage. Second, various biological processes known to be mobilized under oxidative stress were shown to be altered by OTA. These effects have been observed in both in vitro and in vivo test systems. In vivo, active doses were often within doses documented to induce renal tumors in rats. In conclusion, the evidence for the induction of an oxidative stress response resulting from OTA exposure can be considered strong. Because the contribution of the oxidative stress response in the development of cancers is well established, a role in OTA carcinogenicity is plausible. Altogether, the data reviewed above support the application of a threshold-based approach to establish safe level of dietary human exposure to OTA.
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Affiliation(s)
- M. Marin-Kuan
- Chemical Food Safety Group, Quality & Safety Department, Nestlé Research Center, P.O. Box 44, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland
| | - V. Ehrlich
- Chemical Food Safety Group, Quality & Safety Department, Nestlé Research Center, P.O. Box 44, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland
| | - T. Delatour
- Chemical Food Safety Group, Quality & Safety Department, Nestlé Research Center, P.O. Box 44, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland
| | - C. Cavin
- Chemical Food Safety Group, Quality & Safety Department, Nestlé Research Center, P.O. Box 44, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland
| | - B. Schilter
- Chemical Food Safety Group, Quality & Safety Department, Nestlé Research Center, P.O. Box 44, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland
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22
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Rakib MA, Kim YS, Jang WJ, Choi BD, Kim JO, Kong IK, Ha YL. Attenuation of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced gap junctional intercellular communication (GJIC) inhibition in MCF-10A cells by c9,t11-conjugated linoleic acid. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:12022-12030. [PMID: 21028875 DOI: 10.1021/jf103205c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The protective effect of c9,t11-conjugated linoleic acid (CLA) on the inhibition of gap junctional intercellular communication (GJIC) was examined in a human mammary epithelial cell line (MCF-10A) treated with 12-O-tetradecanoylphorbol-13-acetate (TPA), relative to t10,c12-CLA isomer. TPA inhibited GJIC in a dose-dependent and reversible manner and was associated with connexin 43 phosphorylation. Pretreatment of 20 μM c9,t11-CLA for 24 h prior to 60 nM TPA for 1 h prevented the inhibition of GJIC by reducing the phosphorylation of connexin 43 via suppressing extracellular signal-regulated kinases (ERK1/2) activation. Reactive oxygen species (ROS) accumulation by TPA was attenuated by c9,t11-CLA. The efficacy of c9,t11-CLA in protecting inhibition of GJIC, connexin 43 phosphorylation, and ROS production was superior to that of t10,c12-CLA. These results suggest that c9,t11-CLA, including t10,c12-CLA, prevents the carcinogenesis of MCF-10A cells by protecting down-regulation of GJIC during the cancer promotion stage, and lack of their toxicities could be an excellent indicator for the chemoprevention of breast cancer.
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Affiliation(s)
- Md Abdur Rakib
- Division of Applied Life Science (BK21 Program), Graduate School, and Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 660-701, Republic of Korea
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23
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Trosko JE, Upham BL. A paradigm shift is required for the risk assessment of potential human health after exposure to low level chemical exposures: a response to the toxicity testing in the 21st century report. Int J Toxicol 2010; 29:344-57. [PMID: 20634539 DOI: 10.1177/1091581810371384] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Chemicals are known to be associated with birth defects, cancer, cardiovascular diseases, immunological, reproductive, and neurological disorders. In response to recent reviews of limitations of current concepts and techniques for toxicity testing, this commentary challenges the paradigm that chemicals are directly responsible for DNA damage in the genomic-nuclear DNA in relevant cells of the human body. This challenge is not that mutations do not play roles in human-inherited or somatic diseases but that chemical exposures bring about disease end points by epigenetic mechanisms or by alterations in adult stem cell numbers in utero (ie, the Barker hypothesis) or postnatally, by selecting preexisting mutated cells. Classic concepts, that is, multistage, multimechanism process of carcinogenesis, stem cell theory of cancer, and newer and ignored concepts, such as cancer stem cells and cell-cell communication, will be used to support the view that the toxic effect of chemicals is mediated by nonmutagenic mechanisms at human relevant exposures.
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Affiliation(s)
- James E Trosko
- Department Pediatrics and Human Development, College of Human Medicine, Michigan State University, East Lansing, MI 48824, USA.
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24
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Vinken M, Ceelen L, Vanhaecke T, Rogiers V. Inhibition of Gap Junctional Intercellular Communication by Toxic Metals. Chem Res Toxicol 2010; 23:1862-7. [DOI: 10.1021/tx100276f] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mathieu Vinken
- Department of Toxicology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Liesbeth Ceelen
- Department of Toxicology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Tamara Vanhaecke
- Department of Toxicology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Vera Rogiers
- Department of Toxicology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
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25
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Tan HL, Thomas-Ahner JM, Grainger EM, Wan L, Francis DM, Schwartz SJ, Erdman JW, Clinton SK. Tomato-based food products for prostate cancer prevention: what have we learned? Cancer Metastasis Rev 2010; 29:553-68. [PMID: 20803054 PMCID: PMC3806204 DOI: 10.1007/s10555-010-9246-z] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Evidence derived from a vast array of laboratory studies and epidemiological investigations have implicated diets rich in fruits and vegetables with a reduced risk of certain cancers. However, these approaches cannot demonstrate causal relationships and there is a paucity of randomized, controlled trials due to the difficulties involved with executing studies of food and behavioral change. Rather than pursuing the definitive intervention trials that are necessary, the thrust of research in recent decades has been driven by a reductionist approach focusing upon the identification of bioactive components in fruits and vegetables with the subsequent development of single agents using a pharmacologic approach. At this point in time, there are no chemopreventive strategies that are standard of care in medical practice that have resulted from this approach. This review describes an alternative approach focusing upon development of tomato-based food products for human clinical trials targeting cancer prevention and as an adjunct to therapy. Tomatoes are a source of bioactive phytochemicals and are widely consumed. The phytochemical pattern of tomato products can be manipulated to optimize anticancer activity through genetics, horticultural techniques, and food processing. The opportunity to develop a highly consistent tomato-based food product rich in anticancer phytochemicals for clinical trials targeting specific cancers, particularly the prostate, necessitates the interactive transdisciplinary research efforts of horticulturalists, food technologists, cancer biologists, and clinical translational investigators.
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Affiliation(s)
- Hsueh-Li Tan
- The Ohio State University Nutrition (OSUN) Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | | | | | - Lei Wan
- The Ohio State University Nutrition (OSUN) Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - David M. Francis
- Department of Horticulture and Crop Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691, USA
| | - Steven J. Schwartz
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
- Department of Food Science and Technology, College of Food, Agriculture, and Environmental Science, The Ohio State University, Columbus, OH 43210, USA
| | - John W. Erdman
- Department of Food Science and Human Nutrition and the Division of Nutritional Sciences, University of Illinois, Urbana, IL 61801, USA
| | - Steven K. Clinton
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
- Division of Medical Oncology, Department of Internal Medicine, College of Medicine, The Ohio State University, A456 Starling Loving Hall, 320 West 10th Ave, Columbus, OH 43210, USA
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26
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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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27
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Giesy JP, Naile JE, Khim JS, Jones PD, Newsted JL. Aquatic toxicology of perfluorinated chemicals. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2010; 202:1-52. [PMID: 19898760 DOI: 10.1007/978-1-4419-1157-5_1] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- John P Giesy
- Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, S7N 5B3, Saskatoon, Saskatchewan, Canada.
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28
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Trosko JE. Review Paper: Cancer Stem Cells and Cancer Nonstem Cells: From Adult Stem Cells or from Reprogramming of Differentiated Somatic Cells. Vet Pathol 2009; 46:176-93. [DOI: 10.1354/vp.46-2-176] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Two opposing hypotheses of the origin of cancer have existed for many decades. One hypothesis postulates that the adult stem cell is needed to initiate the carcinogenic process, whereas the other claims a somatic differentiated cell can dedifferentiate or be reprogrammed to regain properties associated with cancer cells. Recent reemergence of the cancer stem cell hypothesis and the isolation of presumptive cancer stem cells from many types of cancer have forced a reexamination of these 2 hypotheses of the origin of cancer. In addition, normal embryonic and adult stem cells have now been isolated and partially characterized. Furthermore, the demonstration of embryonic-like stem cells, being isolated from adult-differentiated skin fibroblast cells of mice, monkey, and human beings, provides a newer opportunity to determine which of these 2 hypotheses might explain the cell type for initiating the carcinogenic process. The goal of this review is to integrate these recent findings, concerning the isolation of normal and cancer stem cells, with several of the classical concepts of carcinogenesis (initiation/promotion/progression; mutation/epigenetic; stem cell theory/dedifferentiation hypotheses; oncogenetumor suppressor theory). Although the weight of the evidence in this review seems to support the stem cell hypothesis, only future studies, probably using comparative animal and human oncologic studies, will determine if targeting the cancer stem cell, with individualized medical approaches, will improve cancer prevention and therapy.
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Affiliation(s)
- J. E. Trosko
- Center for Integrative Toxicology, National Food Safety Toxicology Center, Department of Pediatrics/Human Development, College of Human Medicine, Michigan State University, East Lansing, Mi
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29
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Kim JH, Lee BK, Lee KW, Lee HJ. Resveratrol counteracts gallic acid-induced down-regulation of gap-junction intercellular communication. J Nutr Biochem 2009; 20:149-54. [DOI: 10.1016/j.jnutbio.2008.01.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 12/31/2007] [Accepted: 01/10/2008] [Indexed: 11/16/2022]
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30
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Mein JR, Lian F, Wang XD. Biological activity of lycopene metabolites: implications for cancer prevention. Nutr Rev 2009; 66:667-83. [PMID: 19019036 DOI: 10.1111/j.1753-4887.2008.00120.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
While early studies focused on the potential roles in health and disease of provitamin A carotenoids, such as beta-carotene, research over the past decade has provided a framework for our understanding of the functions of non-provitamin A carotenoids such as lycopene, especially in regards to its association with a reduced risk of a number of chronic diseases, including cancer. Recent data suggests that lycopene metabolites may possess specific biological activities on several important cellular signaling pathways and molecular targets. Carotenoid metabolites may have more important biological roles than their parent compounds in human health and disease. This notion has been reinforced by the observation of both beneficial and detrimental effects of carotenoid metabolites in cancer prevention.
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Affiliation(s)
- Jonathan R Mein
- Nutrition and Cancer Biology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts 02111, USA
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31
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Hwang JW, Jung JW, Lee YS, Kang KS. Indole-3-carbinol prevents H(2)O(2)-induced inhibition of gap junctional intercellular communication by inactivation of PKB/Akt. J Vet Med Sci 2008; 70:1057-63. [PMID: 18981661 DOI: 10.1292/jvms.70.1057] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Indole-3-carbinol (I3C) is a phytochemical found in cruciferous vegetables and possesses a variety of biological and biochemical effects. Despite a wealth of data about the chemopreventive properties of I3C, its effects on gap junctional intercellular communication (GJIC), which is associated with the promotion and progression phases of the multi-stage process of carcinogenesis, has not been studied. In this study, we examined the ability of I3C to prevent H(2)O(2)-induced inhibition of GJIC in WB-F344 rat liver epithelial cells (WB cells). The cells were preincubated with I3C for 48 hr, and then treated with 1 mM H(2)O(2) for 1 hr. We found that I3C could prevent the H(2)O(2)-induced inhibition of GJIC through prevention of the phosphorylated state of gap junction protein connexin 43 (Cx43) phosphorylation. Prevention of GJIC by I3C was dependent upon inactivation of Akt, but not MAPK, although inhibition of GJIC by H(2)O(2) leads to activation of both. Similar to I3C, modulation of Akt activation through the phosphoinositide-3 kinase inhibitor, LY294002, could also prevent H(2)O(2)-induced inhibition of GJIC and phosphorylation of Cx43. Our results suggest that I3C might exert its dietary chemopreventive effects by interfering with the Akt signaling pathway, which appears to be linked to modulating GJIC, a cellular mechanisms regulating cell proliferation, differentiation and apoptosis.
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Affiliation(s)
- Jae-Woong Hwang
- Laboratory of Stem Cell and Tumor Biology, Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, Seoul, South Korea
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Yoo H, Kannan K, Kim SK, Lee KT, Newsted JL, Giesy JP. Perfluoroalkyl acids in the egg yolk of birds from Lake Shihwa, Korea. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:5821-7. [PMID: 18754515 DOI: 10.1021/es800447d] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Concentrations of perfluoroalkyl acids (PFAs) were measured in egg yolks of three species of birds, the little egret (Egretta garzetta), little ringed plover (Charadrius dubius), and parrot bill (Paradoxornis webbiana), collected in and around Lake Shihwa, Korea, which receives wastewaters from an adjacent industrial complex. Mean concentrations of perfluorooctanesulfonate (PFOS) ranged from 185 to 314 ng/g ww and were similar to those reported for bird eggs from other urban areas. Long-chain perfluorocarboxylic acids (PFCAs) were also found in egg yolks often at great concentrations. Mean concentrations of perfluoroundecanoic acid (PFUnA) ranged from 95 to 201 ng/g ww. Perfluorooctanoic acid was detected in 32 of 44 egg samples, but concentrations were 100-fold less than those of PFOS. Relative concentrations of PFAs in all three species were similar with the predominance of PFOS (45-50%). There was a statistically significant correlation between PFUnA and perfluorodecanoic acid in egg yolks (p < 0.05), suggesting a common source of PFCAs. Using measured egg concentrations and diet concentrations, the ecological risk of the PFOS and PFA mixture to birds in Lake Shihwa was evaluated using two different approaches. Estimated hazard quotients were similar between the two approaches. The concentration of PFOS associated with 90th centile in bird eggs was 100-fold less than the lowest observable adverse effect level determined for birds, and those concentrations were 4-fold less than the suggested toxicity reference values. On the basis of limited toxicological data, current concentrations of PFOS are less than what would be expected to have an adverse effect on birds in the Lake Shihwa region.
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Affiliation(s)
- Hoon Yoo
- National Food Safety and Toxicology Center, Zoology Department and Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824, USA
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Dietz R, Bossi R, Rigét FF, Sonne C, Born EW. Increasing perfluoroalkyl contaminants in east greenland polar bears (Ursus maritimus): a new toxic threat to the Arctic bears. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:2701-7. [PMID: 18505019 DOI: 10.1021/es7025938] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A well-defined subsample of 128 subadult (3-5 years) polar bears (Ursus maritimus) from 19 sampling years within the period 1984-2006 was investigated for perfluoroalkyl contaminants (PFCs). Linear regression analysis of logarithmic-transformed median concentrations showed significant annual increases for PFOS (4.7%), PFNA (6.1%), PFUnA (5.9%), PFDA (4.3%), PFTrA (8.5%), PFOA (2.3%), and PFDoA (5.2%). For four of the PFCs, a LOESS smoother model provided significantly better descriptions, revealing steeper linear annual increases for PFOSA of 9.2% after 1990 and between 18.6 and 27.4% for PFOS, PFDA, and PFTrA after 2000. Concentrations of SigmaPFCs, by 2006, exceeded the concentrations of all conventional OHCs (organohalogen compounds), of which several have been documented to correlate with a number of negative health effects. If the PFC concentrations in polar bears continue to increase with the steepest observed trends, then the lowest no-adverse-effect level (NOAEL) and lowest-adverse-effect level (LOAEL) detected for rats and monkeys will be exceeded in 2014-2024. In addition, the rapidly increasing concentrations of PFCs are likely to cause cumulative and combined effects on the polar bear, compounding the already detected threats from OHCs.
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Affiliation(s)
- R Dietz
- Department of Arctic Environment, National Environmental Research Institute, University of Aarhus, Frederiksborgvej 399, P. O. Box 358, DK-4000 Roskilde, Denmark.
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de Montgolfier B, Fournier M, Audet C, Marcogliese DJ, Cyr DG. Influence of municipal effluents on the expression of connexins in the brook trout (Salvelinus fontinalis) testis. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2008; 86:38-48. [PMID: 18006156 DOI: 10.1016/j.aquatox.2007.09.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 09/12/2007] [Accepted: 09/21/2007] [Indexed: 05/06/2023]
Abstract
Gap junctions are essential for spermatogenesis. Exposure to municipal wastewater effluent can modify spermatogenesis in fish. The present aim was to determine if municipal wastewater effluent could alter the expression of testicular connexins (Cxs) in brook trout. Trout were exposed for 4 and 12 weeks to various concentrations of municipal effluent (0, 1, 10 and 20%, v/v). Hepatic vitellogenin (vtg) mRNA levels were not different between exposure groups after 4 weeks. At this time, testicular cx43 and cx31 mRNA levels increased in the 1% group, but cx30 and cx43.4 levels were not different at any concentration. Immunolocalization of each Cx did not differ between groups after 4 weeks. After 12 weeks, spermatogenesis in the 1% group was more advanced than in other groups, and hepatic vtg mRNA levels were significantly increased at the higher exposure concentrations. Testicular cx43 mRNA levels were higher than controls at all doses, while cx43.4 levels increased in a dose-dependent manner but remained lower than controls. cx31 mRNA levels were significantly lower in the 1 and 10% groups than in control and 20% group, while cx30 levels did not vary. Immunolocalization of Cxs did not differ between groups except for Cx43.4, which was expressed between spermatocytes in the 1% group. Furthermore, the Cx31 immunoreaction appeared to decrease in testicular blood vessels of fish exposed to the highest dose. Furthermore, vegf mRNA levels were unaltered by treatment at both time points. Thus, long-term exposure to environmental concentrations of wastewater effluent can alter the expression of testicular Cxs.
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Trosko JE. Gap Junctional Intercellular Communication as a Biological “Rosetta Stone” in Understanding, in a Systems Biological Manner, Stem Cell Behavior, Mechanisms of Epigenetic Toxicology, Chemoprevention and Chemotherapy. J Membr Biol 2007; 218:93-100. [DOI: 10.1007/s00232-007-9072-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Accepted: 09/25/2007] [Indexed: 10/22/2022]
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Procházka L, Turánek J, Tesarík R, Knotigová P, Polásková P, Andrysík Z, Kozubík A, Zák F, Sova P, Neuzil J, Machala M. Apoptosis and inhibition of gap-junctional intercellular communication induced by LA-12, a novel hydrophobic platinum(IV) complex. Arch Biochem Biophys 2007; 462:54-61. [PMID: 17466256 DOI: 10.1016/j.abb.2007.03.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 03/20/2007] [Accepted: 03/20/2007] [Indexed: 01/05/2023]
Abstract
A new hydrophobic platinum(IV) complex, LA-12, a very efficient anticancer drug lacking cross-resistance with cisplatin (CDDP), is now being tested in clinical trials. Here we investigated the apoptogenic activity of LA-12 and its effect on gap-junctional intercellular communication (GJIC) in the rat liver epithelial cell line WB-F344. LA-12 induced apoptosis much more efficiently than did CDDP due to a combination of rapid penetration into the cell and attack on DNA, leading to fast activation of p53 and caspase-3. Exposure of WB-F344 cells to LA-12 led to rapid induction of the time- and dose-dependent decrease in GJIC. On the molecular level, loss of GJIC induced by LA-12 was mediated by activation of extracellular signal-regulated kinase (ERK)-1 and ERK-2, as demonstrated by the use of inhibitors of ERK activation. Inhibition of GJIC was linked to rapid hyperphosphorylation of connexin-43 and disappearance of connexon clusters from membranes, which was not observed in the case of CDDP.
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Affiliation(s)
- Lubomír Procházka
- Veterinary Research Institute, Department of Immunology, Brno, Czech Republic
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Trosko JE. Concepts needed to understand potential health effects of chronic low-level radiation exposures: Role of adult stem cells and modulated cell–cell communication. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.ics.2006.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Gagliano N, Donne ID, Torri C, Migliori M, Grizzi F, Milzani A, Filippi C, Annoni G, Colombo P, Costa F, Ceva-Grimaldi G, Bertelli AAE, Giovannini L, Gioia M. Early cytotoxic effects of ochratoxin A in rat liver: a morphological, biochemical and molecular study. Toxicology 2006; 225:214-24. [PMID: 16857307 DOI: 10.1016/j.tox.2006.06.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 06/01/2006] [Accepted: 06/06/2006] [Indexed: 11/18/2022]
Abstract
We characterized the overall early effect of chronic ochratoxin A (OTA) treatment on rat liver, analyzing different aspects related to: (i) fibrosis, by measuring collagen content and turnover, and alpha-smooth muscle actin (alphaSMA); (ii) oxidative stress and stress response, by analyzing protein carbonylation, superoxide dismutase (SOD) and heat shock protein (HSP70) gene expression; (iii) the possible tumor promoter effect, evaluating cadherin and connexin (CX) mRNA levels. Light microscopy analysis showed no histological differences in OTA-treated and control (CT) rats. Collagen content, determined by computer analysis of Sirius red-stained liver sections, was similar in both groups. In liver homogenates COL-I, COL-III, TIMP-1 and TGF-beta1 mRNA levels and alphaSMA were unaffected by OTA. Matrix metalloproteinase (MMP)-1, MMP-2 and MMP-9 protein levels were also similar in the two groups. Protein carbonylation, a marker of severe oxidative stress, was not evident in the homogenates of OTA-treated livers; superoxide dismutase (SOD) mRNA tended to be lower and HSP70 was strongly down-regulated. OTA reduced E-cadherin and DSC-2 transcription, and down-regulated liver CX26, CX32 and CX43. In conclusion, these in vivo results show that OTA-induced liver injury involves a reduction in the ability to counterbalance oxidative stress, maybe leading to altered gap junction intercellular communication and loss of cell adhesion and polarity. This suggests that mild oxidative damage might be a key factor, in combination with other cytotoxic effects, in triggering the promotion of liver tumors after exposure to OTA.
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Affiliation(s)
- Nicoletta Gagliano
- Department of Human Morphology-LITA Segrate, Via Fratelli Cervi 93, 20090 Segrate, Milan, Italy.
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Lee KW, Lee HJ. Biphasic effects of dietary antioxidants on oxidative stress-mediated carcinogenesis. Mech Ageing Dev 2006; 127:424-31. [PMID: 16519920 DOI: 10.1016/j.mad.2006.01.021] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2006] [Indexed: 02/02/2023]
Abstract
There is now strong evidence implicating the generation of reactive oxygen species (ROS) and the corresponding response to oxidative stress as key factors in the pathogenesis of several human diseases including cancer, atherosclerosis, and neurodegenerative disorders, and in ageing. The carcinogenicity of oxidative stress is primarily attributable to the genotoxicity of ROS, but ROS can promote cancer through diverse cellular processes. Therefore, dietary or pharmaceutical augmentation of the endogenous antioxidant defense capacity has been considered a plausible way to prevent ROS-mediated carcinogenicity, but actual antioxidant therapies have been equivocal at best. In fact, most free-radical scavengers act in reversible oxidation-reduction reactions, and some antioxidants can act both as antioxidants and prooxidants, depending on their structures and the conditions. This article summarizes the possible cancer-preventive and -enhancing mechanisms of dietary antioxidants, with an emphasis on epigenetic mechanisms.
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Affiliation(s)
- Ki Won Lee
- Department of Food Science and Technology, School of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Republic of Korea
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Hakulinen P, Rintala E, Mäki-Paakkanen J, Komulainen H. Altered expression of connexin43 in the inhibition of gap junctional intercellular communication by chlorohydroxyfuranones in WB-F344 rat liver epithelial cells. Toxicol Appl Pharmacol 2006; 212:146-55. [PMID: 16122772 DOI: 10.1016/j.taap.2005.07.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 07/04/2005] [Accepted: 07/19/2005] [Indexed: 11/17/2022]
Abstract
3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), 3,4-dichloro-5-hydroxy-2(5H)-furanone (MCA), and 3-chloro-4-methyl-5-hydroxy-2(5H)-furanone (MCF) promote foci formation in the two-stage cell transformation assay in vitro. These chlorohydroxyfuranones (CHFs) and their structural congener 3-chloro-4-(chloromethyl)-5-hydroxy-2(5H)-furanone (CMCF) inhibit gap junctional intercellular communication (GJIC) in Balb/c 3T3 mouse fibroblast cells. In the present study, the effects of MX, MCA, CMCF, and MCF on GJIC were evaluated in liver cells (WB-F344 rat liver epithelial cells), the target cells of MX-induced carcinogenicity, using the scrape-loading dye transfer technique. The CHFs inhibited GJIC after 1 h exposure in a concentration-dependent fashion. The order of potency was MX>CMCF approximately MCA>MCF. In terms of the lowest observed effective concentrations, the difference in the potency was about 27-fold (MX 1.875 microM, MCF 50 microM). After a prolonged exposure period (12 h), the inhibition of GJIC by MX and CMCF remained stable, but MCA and MCF exhibited increasing inhibitory effects. After removal of the CHFs, the GJIC slowly recovered. At the transcriptional level, CHFs caused essentially no change in the level of connexin43 (Cx43) mRNA. Preincubation of cells with the protein kinase C (PKC) inhibitor did not modify the response, but the specific MEK 1 inhibitor PD98059 decreased substantially the inhibition of GJIC by all four CHFs. Activation of the mitogen-activated protein kinases (MAPKs) signaling pathway was necessary for inhibition of GJIC. CHFs did not increase the basal phosphorylation state of the Cx43 protein, but all CHFs caused a concentration-dependent degradation of the Cx43 protein. The results indicate that all the studied CHFs inhibit GJIC in WB-F344 cells by altering Cx43 expression.
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Affiliation(s)
- Pasi Hakulinen
- National Public Health Institute, Laboratory of Toxicology, P.O.B. 95, FI-70701 Kuopio, Finland.
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Perez Velazquez JL, Kokarovtseva L, Sarbaziha R, Jeyapalan Z, Leshchenko Y. Role of gap junctional coupling in astrocytic networks in the determination of global ischaemia-induced oxidative stress and hippocampal damage. Eur J Neurosci 2006; 23:1-10. [PMID: 16420410 DOI: 10.1111/j.1460-9568.2005.04523.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
While there is evidence that gap junctions play important roles in the determination of cell injuries, there is not much known about mechanisms by which gap junctional communication may exert these functions. Using a global model of transient ischaemia in rats, we found that pretreatment with the gap junctional blockers carbenoxolone, 18alpha-glycyrrhetinic acid and endothelin, applied via cannulae implanted into the hippocampus in one hemisphere, resulted in decreased numbers of TUNEL-positive neurons, as compared with the contralateral hippocampus that received saline injection. Post-treatment with carbenoxolone for up to 30 min after the stroke injury still resulted in decreased cell death, but post-treatment at 90 min after the ischaemic insult did not result in differences in cell death. However, quinine, an inhibitor of Cx36-mediated gap junctional coupling, did not result in appreciable neuroprotection. Searching for a possible mechanism for the observed protective effects, possible actions of the gap junctional blockers in the electrical activity of the hippocampus during the ischaemic insult were assessed using intracerebral recordings, with no differences observed between the saline-injected and the contralateral drug-injected hippocampus. However, a significant reduction in lipid peroxides, a measure of free radical formation, in the hippocampus treated with carbenoxolone, revealed that the actions of gap junctional coupling during injuries may be causally related to oxidative stress. These observations suggest that coupling in glial networks may be functionally important in determining neuronal vulnerability to oxidative injuries.
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Affiliation(s)
- Jose L Perez Velazquez
- Brain and Behaviour Programme and Division of Neurology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
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Abstract
Oxidative stress and associated mechanisms involving inflammation, aberrant signaling pathways and gap junction intercellular communication is increasingly associated with the pathogenesis of various chronic degenerative disorders such as atherosclerosis, neurodegeneration and cancer. Consumption of fruits, vegetables and beverages like teas continues to be suggested to have the capacity to reduce the incidence of cancer. The bioactive compounds including phenolics may be responsible for the chemopreventive effects. While the free radical scavenging and antioxidant properties of phenolics are well established, emerging literature reports suggest that their chemopreventive effects may also be ascribed to their ability to modulate components of cell signaling pathways. This paper reviews the potential chemoprevention role of phenolics with a focus on cellular signal transduction mechanisms and prevention of gap junction intercellular communication relevant to cancer.
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Affiliation(s)
- Muhammad A Soobrattee
- Department of Biosciences, Faculty of Science, University of Mauritius, Réduit, Republic of Mauritius
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Abstract
It has become increasingly evident that the field of neurotoxicology is not only rapidly growing but also rapidly evolving, especially over the last 20 years. As the number of drugs and environmental and bacterial/viral agents with potential neurotoxic properties has grown, the need for additional testing has increased. Only recently has the technology advanced to a level that neurotoxicologic studies can be performed without operating in a "black box." Examination of the effects of agents that are suspected of being toxic can occur on the molecular (protein-protein), cellular (biomarkers, neuronal function), and genetic (polymorphisms) level. Together, these areas help to elucidate the potential toxic profiles of unknown (and in some cases, known) agents. The area of proteomics is one of the fastest growing areas in science and particularly applicable to neurotoxicology. Lubec et al, provide a review of the potential and limitations of proteomics. Proteomics focuses on a more comprehensive view of cellular proteins and provides considerably more information about the effects of toxins on the CNS. Proteomics can be classified into three different focuses: post-translational modification, protein-expression profiling, and protein-network mapping. Together, these methods represent a more complete and powerful image of protein modifications following potential toxin exposure. Cellular neurotoxicology involves many cellular processes including alterations in cellular energy homeostasis, ion homeostasis, intracellular signaling function, and neurotransmitter release, uptake, and storage. The greatest hurdle in cellular neurotoxicology has been the discovery of appropriate biomarkers that are reliable, reproducible, and easy to obtain. There are biomarkers of exposure effect, and susceptibility. Finding the appropriate biomarker for a particular toxin is a daunting task. The appropriate biomarker for a particular toxin is a daunting task. The advantage to biomarker/toxin combinations is they can be detected and measured shortly following exposure and before overt neuroanatomic damage or lesions. Intervention at this point, shortly following exposure, may prevent or at least attenuate further damage to the individual. The use of peripheral biomarkers to assess toxin damage in the CNS has numerous advantages: time-course analysis may be performed, ethical concerns with the use of human subjects can partially be avoided, procedures to acquire samples are less invasive, and in general, peripheral studies are easier to perform. Genetic neurotoxicology comprises two focuses--toxin-induced alterations in genetic expression and genetic alterations that affect toxin metabolism, distribution, and clearance. These differences can be beneficial or toxic. Polymorphisms have been shown to result in altered metabolism of certain toxins (paraoxonase and paraoxon). Conversely, it is possible that some polymorphisms may be beneficial and help prevent the formation of a toxic by-product of an exogenous agent (resistance to ozone-induced lung inflammation). It has also become clear that interactions of potential toxins are not straightforward as interactions with DNA, causing mutations. There are numerous agents that cause epigenetic responses (cellular alterations that are not mutagenic or cytotoxic). This finding suggests that many agents that may originally have been thought of as nontoxic should be re-examined for potential "indirect" toxicity. With the advancement of the human genome project and the development of a human genome map, the effects of potential toxins on single or multiple genes can be identified. Although collectively, the field of neurotoxicology has recently come a long way, it still has a long way to go reach its full potential. As technology and methodology advances continue and cooperation with other disciplines such as neuroscience, biochemistry, neurophysiology, and molecular biology is improved, the mechanisms of toxin action will be further elucidated. With this increased understanding will come improved clinical interventions to prevent neuronal damage following exposure to a toxin.
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Affiliation(s)
- David R Wallace
- Department of Pharmacology and Physiology, Oklahoma State University Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107-1898, USA.
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Rosenkranz HS, Cunningham AR. Lack of predictivity of the rat lethality (LD50) test for ecological and human health effects. Altern Lab Anim 2005; 33:9-19. [PMID: 15804213 DOI: 10.1177/026119290503300104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The relationship between acute toxicity in rats (LD50 values) and indicators of potential health hazards in humans was investigated, based on a chemical population-based paradigm (i.e. the "chemical diversity approach"). These structure-activity relationship-based analyses indicate that high toxicity in rats (i.e. a low LD50 value) is not a good predictor of health effects in humans. In fact, it was found that high acute toxicity to minnows, as well as toxicity to cultured cells, showed significantly greater associations with the potential for health effects than rat LD50 values.
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Affiliation(s)
- Herbert S Rosenkranz
- Department of Biomedical Sciences, Florida Atlantic University, 777 Glades Road, P.O. Box 3091, Boca Raton, FL 33431-0991, USA
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Trosko JE, Upham BL. The emperor wears no clothes in the field of carcinogen risk assessment: ignored concepts in cancer risk assessment. Mutagenesis 2005; 20:81-92. [PMID: 15784692 DOI: 10.1093/mutage/gei017] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The following is a position paper challenging the paradigm that 'carcinogen = mutagen', and that the current rodent bioassay to predict risks to human cancers is relevant and useful. Specifically, we review current observations concerning carcinogenesis that might lead to another approach for assessing the identification of human carcinogenic hazards and the risk assessment that chemicals might pose. We give a brief review of the multistage and multimechanism process of cancer in a tissue that involves not only genotoxic but also epigenetic events, and the importance of stem and progenitor cells in the development of cancer. We focus on the often ignored 'epigenetic' effects of carcinogens and the role of cell communication systems in epigenetically altering gene expression that leads to an imbalance of cell proliferation, differentiation and apoptosis in a tissue that can contribute to the cancer process. To draw attention to the fact that the current paradigm and policy to test toxic chemicals is often misleading and incorrect, we discuss how oxidative stress, in spite of the DNA damaging data, most probably contributes to cancer at the epigenetic level. Additionally, we briefly review how this mutagenic concept has greatly diverted attention away from doing research on the lower molecular weight, non-genotoxic, polycyclic aromatic hydrocarbons (PAHs), and how these low molecular weight PAHs are etiologically more relevant to the disease potential of environmental mixtures such as cigarette smoke.
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Affiliation(s)
- James E Trosko
- National Food Safety Toxicology Center, Department of Pediatrics and Human Development, Michigan State University, East Lansing, MI 48824, USA.
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Trosko JE. The role of stem cells and cell–cell communication in radiation carcinogenesis: ignored concepts. Br J Radiol 2005. [DOI: 10.1259/bjr/75133009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Hakulinen P, Mäki-Paakkanen J, Naarala J, Kronberg L, Komulainen H. Potent inhibition of gap junctional intercellular communication by 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) in BALB/c 3T3 cells. Toxicol Lett 2004; 151:439-49. [PMID: 15261988 DOI: 10.1016/j.toxlet.2004.03.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2003] [Revised: 02/26/2004] [Accepted: 03/04/2004] [Indexed: 11/18/2022]
Abstract
The chlorohydroxyfuranones (CHFs) MX [3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone], MCA [3,4-dichloro-5-hydroxy-2(5H)-furanone], CMCF [3-chloro-4-(chloromethyl)-5-hydroxy-2(5H)-furanone], and MCF [3-chloro-4-methyl-5-hydroxy-2(5H)-furanone] are genotoxic disinfection by-products of drinking water chlorination. MX, MCA, and MCF also promote foci formation in the two-stage cell transformation assay. The cellular mechanisms underlying this apparent promotional effect are not known. In the present study, the effects of MX, MCA, CMCF, and MCF on gap junctional intercellular communication (GJIC) were measured in BALB/c 3T3 cells using the scrape loading dye technique. The effect of MX on apoptosis in the same cell line was explored by assaying caspase-3-like protease activity. All the four CHFs inhibited GJIC after 30 min exposure in a dose-dependent fashion but there was a marked difference in the ranges of their active concentrations. MX was almost as potent an inhibitor of GJIC (inhibition at nanomolar concentrations) as 12-O-tetradecanoylphorbol-13-acetate (TPA) (positive control), while MCA was 10 times weaker, CMCF 10,000 times weaker, and MCF 20,000 times weaker than MX. After prolonged exposure periods (up to 6 h), GJIC recovered somewhat upon MX and MCA exposures, the inhibition of GJIC by MCF remained constant but CMCF showed an irreversible increasing inhibitory effect. MX caused apoptosis as a "window" effect at concentrations 2000-4000-fold higher than those needed to inhibit GJIC. The results indicate that MX is a potent inhibitor of GJIC in BALB/c 3T3 cells and this inhibition might be one mechanism by which MX can promote malignant foci formation. MCA also has a specific potential to inhibit GJIC whereas MCF and CMCF affected GJIC at concentrations, similar to those evoking genotoxicity in vitro.
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Affiliation(s)
- Pasi Hakulinen
- National Public Health Institute, Laboratory of Toxicology, P.O. Box 95, Kuopio FIN-70701, Finland.
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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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Abstract
Several studies have reported that even a moderate daily dose of supplementary vitamin C (200 mg) induces the formation of genotoxins from lipid hydroperoxides, thereby resulting in DNA damage and initiation of carcinogenesis. However, other reports questioned the experimental designs used and suggested that the chemopreventive effects of vitamin C may be linked to the inhibition of tumor promotion as well as to the blocking of tumor initiation. In this article, we discuss issues of contention and some controversies related to the potential chemopreventive effects of vitamin C in carcinogenesis.
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Affiliation(s)
- Ki Won Lee
- Department of Food Science and Technology, School of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
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Abstract
The health risk manager and policy analyst must frequently make recommendations based upon incomplete toxicity data. This is a situation which is encountered in the evaluation of human carcinogenic risks as animal cancer bioassay results are often not available. In this study, in order to assess the relevance of other possible indicators of carcinogenic risks, we used the "chemical diversity approach" to estimate the magnitude of the human carcinogenic risk based upon Salmonella mutagenicity and systemic toxicity data of the "universe of chemicals" to which humans have the potential to be exposed. Analyses of the properties of 10,000 agents representative of the "universe of chemicals" suggest that chemicals that have genotoxic potentials as well as exhibiting greater systemic toxicity are more likely to be carcinogens than non-genotoxicants or agents that exhibit lesser toxicity. Since "genotoxic" carcinogenicity is a hallmark of recognized human carcinogens, these findings are relevant to human cancer risk assessment.
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Affiliation(s)
- Herbert S Rosenkranz
- Department of Biomedical Sciences, Florida Atlantic University, 777 Glades Road, PO Box 3091, Boca Raton, FL 33431, USA.
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