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Won DH, Hwang DB, Kim C, Kang M, Jeon Y, Park YI, Che JH, Yun JW. Genotoxic carcinogen 7,12-dimethylbenz[a]anthracene inhibits gap junction intercellular communication through post-transcriptional and post-translational processing involved in connexin 43 stability. Food Chem Toxicol 2023; 174:113695. [PMID: 36863560 DOI: 10.1016/j.fct.2023.113695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 02/22/2023] [Accepted: 02/25/2023] [Indexed: 03/04/2023]
Abstract
Gap junctional intercellular communication (GJIC) is composed of connexin (Cx) and plays an important role in maintaining intracellular homeostasis. Loss of GJIC is involved in the early stages of cancer pathways of non-genotoxic carcinogens; however, the effect of genotoxic carcinogens, including polycyclic aromatic hydrocarbons (PAHs), on GJIC function remains unclear. Therefore, we determined whether and how a representative PAH 7,12-dimethylbenz[a]anthracene (DMBA) suppresses GJIC in WB-F344 cells. First, DMBA significantly inhibited GJIC and dose-dependently reduced Cx43 protein and mRNA expression. In contrast, Cx43 promoter activity was upregulated after DMBA treatment via the induction of specificity protein 1 and hepatocyte nuclear factor 3β, indicating that the promoter-independent loss of Cx43 mRNA can be associated with the inhibition of mRNA stability, which was verified by actinomycin D assay. In addition to a decrease in mRNA stability involved in human antigen R, we also observed DMBA-induced acceleration of Cx43 protein degradation, which was closely related to the loss of GJIC through Cx43 phosphorylation via MAPK activation. In conclusion, the genotoxic carcinogen DMBA suppresses GJIC by inhibiting post-transcriptional and post-translational processing of Cx43. Our findings suggest that the GJIC assay is an efficient short-term screening test for predicting the carcinogenic potential of genotoxic carcinogens.
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Affiliation(s)
- Dong-Hoon Won
- Department of Biotechnology, The Catholic University of Korea, Bucheon, 14662, South Korea
| | - Da-Bin Hwang
- Department of Biotechnology, The Catholic University of Korea, Bucheon, 14662, South Korea
| | - Changuk Kim
- Department of Biotechnology, The Catholic University of Korea, Bucheon, 14662, South Korea
| | - MinHwa Kang
- Laboratory of Veterinary Toxicology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea
| | - Young Jeon
- Laboratory of Veterinary Toxicology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yong Il Park
- Department of Biotechnology, The Catholic University of Korea, Bucheon, 14662, South Korea
| | - Jeong-Hwan Che
- Biomedical Center for Animal Resource and Development, Seoul National University College of Medicine, Seoul, 03080, South Korea
| | - Jun-Won Yun
- Laboratory of Veterinary Toxicology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea.
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Vrdoljak N. Carotenoids and Carcinogenesis: Exploring the Antioxidant and Cell Signaling Roles of Carotenoids in the Prevention of Cancer. Crit Rev Oncog 2022; 27:1-13. [PMID: 37183934 DOI: 10.1615/critrevoncog.2022045331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Carotenoids are lipid soluble pigments found in various fruits and vegetables and are naturally produced in photoautotrophic plants. Various studies have investigated the properties of carotenoids to determine how they are able to mitigate numerous diseases, including cancer. Carotenoids present in human serum, including β-carotene, α-carotene, lycopene, β-cryptoxanthin, zeaxanthin, and lutein have demonstrated the ability to act as anticarcinogenic agents. Prevention of disease is often described to be more effective than treatment; as cancer impacts millions of lives globally, the role of carotenoids in the prevention of oncogenesis for numerous types of cancers have been extensively researched. This review provides an in-depth analysis of the structure and properties of carotenoids, as well as the identified and potential mechanisms by which carotenoids can act as a chemopreventative agent.
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Affiliation(s)
- Nikolina Vrdoljak
- Department of Food Science, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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3
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Arabzadeh A, Mortezazadeh T, Aryafar T, Gharepapagh E, Majdaeen M, Farhood B. Therapeutic potentials of resveratrol in combination with radiotherapy and chemotherapy during glioblastoma treatment: a mechanistic review. Cancer Cell Int 2021; 21:391. [PMID: 34289841 PMCID: PMC8296583 DOI: 10.1186/s12935-021-02099-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/15/2021] [Indexed: 02/06/2023] Open
Abstract
Glioblastoma, WHO grade IV astrocytoma, is the most aggressive type of brain tumors. These cancerous cells have a rapid growth rate, tendency to penetrate vital brain structures, molecular heterogeneity, etc. and this cancer is associated with a poor prognosis and low survival rate. Due to the resistance of glioblastoma cells to conventional therapeutic modalities (such as radiation therapy and chemotherapy) as well as the adverse effects of these modalities, the researchers have attempted to discover an appropriate alternative or adjuvant treatment for glioblastoma. Resveratrol, as an herbal and natural polyphenolic compound, has anti-tumoral property and has shown to be effective in GBM treatment. Resveratrol exerts its anti-tumoral effect through various mechanisms such as regulation of cell cycle progression and cell proliferation, autophagy, oxidant system, apoptosis pathways, and so on. Resveratrol in combination with radiation therapy and chemotherapy has also been used. In the present study, we summarized the current findings on therapeutic potentials of resveratrol in glioblastoma radiotherapy and chemotherapy.
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Affiliation(s)
- AmirAhmad Arabzadeh
- Department of Surgery, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
| | - Tohid Mortezazadeh
- Department of Medical Physics, School of Medicine, Tabriz University of Medical Science, Tabriz, Iran
| | - Tayebeh Aryafar
- Department of Radiation Sciences, Yasuj University of Medical Sciences, Yasuj, Iran
| | - Esmaeil Gharepapagh
- Medical Radiation Sciences Research Team , Tabriz University of Medical Science, Tabriz, Iran
| | - Mehrsa Majdaeen
- Department of Radiotherapy and Oncology, Razi Hospital, Guilan University of Medical Sciences, Rasht, Iran.
| | - Bagher Farhood
- Department of Medical Physics and Radiology, Faculty of Paramedical Sciences, Kashan University of Medical Sciences, Kashan, Iran.
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Gap Junction Intercellular Communication in the Carcinogenesis Hallmarks: Is This a Phenomenon or Epiphenomenon? Cells 2019; 8:cells8080896. [PMID: 31416286 PMCID: PMC6721698 DOI: 10.3390/cells8080896] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/03/2019] [Accepted: 08/12/2019] [Indexed: 12/24/2022] Open
Abstract
If occupational tumors are excluded, cancer causes are largely unknown. Therefore, it appeared useful to work out a theory explaining the complexity of this disease. More than fifty years ago the first demonstration that cells communicate with each other by exchanging ions or small molecules through the participation of connexins (Cxs) forming Gap Junctions (GJs) occurred. Then the involvement of GJ Intercellular Communication (GJIC) in numerous physiological cellular functions, especially in proliferation control, was proven and accounts for the growing attention elicited in the field of carcinogenesis. The aim of the present paper is to verify and discuss the role of Cxs, GJs, and GJIC in cancer hallmarks, pointing on the different involved mechanisms in the context of the multi-step theory of carcinogenesis. Functional GJIC acts both as a tumor suppressor and as a tumor enhancer in the metastatic stage. On the contrary, lost or non-functional GJs allow the uncontrolled proliferation of stem/progenitor initiated cells. Thus, GJIC plays a key role in many biological phenomena or epiphenomena related to cancer. Depending on this complexity, GJIC can be considered a tumor suppressor in controlling cell proliferation or a cancer ally, with possible preventive or therapeutic implications in both cases.
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Pro-Apoptotic Effect of Grape Seed Extract on MCF-7 Involves Transient Increase of Gap Junction Intercellular Communication and Cx43 Up-Regulation: A Mechanism of Chemoprevention. Int J Mol Sci 2019; 20:ijms20133244. [PMID: 31269652 PMCID: PMC6651466 DOI: 10.3390/ijms20133244] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 02/06/2023] Open
Abstract
Growing evidence suggests dietary antioxidants reduce the risk of several cancers. Grape seeds extracts (GSE) are a rich source of polyphenols known to have antioxidant, chemopreventive and anticancer properties. Herein, we investigated the in vitro effects and putative action mechanisms of a grape seed extract (GSE) on human breast cancer cells (MCF-7). The effects of GSE were evaluated on cell proliferation, apoptosis and gap-junction-mediated cell-cell communications (GJIC), as basal mechanism involved in the promotion stage of carcinogenesis. GSE (0.05-100 μg/mL) caused a significant dose- and time-dependent inhibition of MCF-7 viability and induced apoptotic cell death, as detected by Annexin-V/Propidium Iodide. Concurrently, GSE induced transient but significant enhancement of GJIC in non-communicating MCF-7 cells, as demonstrated by the scrape-loading/dye-transfer (SL/DT) assay and an early and dose-dependent re-localization of the connexin-43 (Cx43) proteins on plasma membranes, as assayed by immunocytochemistry. Finally, real-time-PCR has evidenced a significant increase in cx43 mRNA expression. The results support the hypothesis that the proliferation inhibition and pro-apoptotic effect of GSE against this breast cancer cell model are mediated by the GJIC improvement via re-localization of Cx43 proteins and up-regulation of cx43 gene, and provide further insight into the action mechanisms underlying the health-promoting action of dietary components.
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Shetty S, Kumar R, Bharati S. Mito-TEMPO, a mitochondria-targeted antioxidant, prevents N-nitrosodiethylamine-induced hepatocarcinogenesis in mice. Free Radic Biol Med 2019; 136:76-86. [PMID: 30946961 DOI: 10.1016/j.freeradbiomed.2019.03.037] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/23/2019] [Accepted: 03/29/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND Oxidative stress and mitochondrial dysfunction play a significant role in hepatocarcinogenesis. Mitochondria are source organelle as well as target for free radicals. The oxidative damage to mitochondria can be prevented by mitochondria-targeted antioxidant, mito-TEMPO. However, its efficacy in prevention of hepatocellular carcinoma has not been investigated so far. METHODS Murine model of hepatocarcinogenesis was developed by intraperitoneal administration of N-nitrosodiethylamine to male BALB/c mice. Mito-TEMPO was administered intraperitoneally at weekly intervals, till the completion of the study. The tumours were histopathologically analysed and anti-cancer efficacy of mito-TEMPO was evaluated in terms of survival index, tumour incidence, tumour multiplicity and tumour dielectric parameters. The antioxidant defence status and molecular composition of tumours were assessed. Gap junctions and gap-junctional intercellular communication (GJIC) were studied using ELISA, IHC and Lucifer yellow assay. RESULTS Mito-TEMPO treatment increased survival of animals by 30%, decreased tumour incidence (25%) and tumour multiplicity (39%). The dielectric parameters of tumours in Mito-TEMPO group were indicative of retarded carcinogenesis. Mito-TEMPO administration normalized mean saturation levels in phospholipids and improved glycogen content of the hepatic tissue. Gap junctions and GJIC which were severely impaired in hepatocarcinogenesis, improved after mito-TEMPO treatment. CONCLUSION Mito-TEMPO was effective in combating hepatocarcinogenesis.
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Affiliation(s)
- Sachin Shetty
- Department of Nuclear Medicine, School of Allied Health Sciences, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India
| | - Rajesh Kumar
- Department of Radiotherapy and Oncology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India
| | - Sanjay Bharati
- Department of Nuclear Medicine, School of Allied Health Sciences, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India.
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Jafarzadeh M, Mousavizadeh K, Joghataei MT, Bahremani MH, Safa M, Asghari SM. A Fibroblast Growth Factor Antagonist Peptide Inhibits Breast Cancer in BALB/c Mice. Open Life Sci 2018; 13:348-354. [PMID: 33817103 PMCID: PMC7874733 DOI: 10.1515/biol-2018-0043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/10/2018] [Indexed: 02/02/2023] Open
Abstract
Objective Given the role of basic fibroblastic growth factor (bFGF) in tumor growth, it has been considered as a potential target for tumor therapy. In this study, we investigate the effect of bFGF antagonistic peptide on the growth and angiogenesis of 4T1 mammary carcinoma tumor (MCT) in BALB/c mice. Methods An engineered peptide was injected into BALB/c mice in doses of 1, 2.5, 5 and 10 mg/kg daily for 14 days. Immunohistochemical analysis using anti-CD31 and anti-CD34 were conducted as indices of angiogenesis. In addition, blood samples were taken from the eyes of treated and control mice and the levels of Interleukin-8 (IL-8) and Tumor Necrosis Factor-α (TNF-α) were measured by ELISA. Data was analyzed by ANOVA using SPSS. Results The antagonistic peptide inhibited growth and angiogenesis of MCT (P ≤0.05), and decreased the serum level of IL-8 and TNF-α in treated groups compared to the control groups. Conclusion The inhibition of tumor angiogenesis has been considered as an important strategy to halt tumor growth. The results of current study confirm that the antiangiogenic peptide effectively inhibited the growth of MCT, and shows potential for clinical trials for the treatment of cancer in humans.
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Affiliation(s)
- Mehrzad Jafarzadeh
- Department of Biology, University Campus2, University of Guilan, Rasht, Iran
| | - Kazem Mousavizadeh
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
- Department of Molecular Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Taghi Joghataei
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Hashemi Bahremani
- Department of Pathology, school of medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Majid Safa
- Department of Hematology, School of Allied Medical Science, Iran University of Medical Sciences, Tehran, Iran
| | - S Mohsen Asghari
- Department of Biology, Faculty of Sciences, University of Guilan, Rasht, Iran
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8
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Connexins and Pannexins: Important Players in Tumorigenesis, Metastasis and Potential Therapeutics. Int J Mol Sci 2018; 19:ijms19061645. [PMID: 29865195 PMCID: PMC6032133 DOI: 10.3390/ijms19061645] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 05/25/2018] [Accepted: 05/28/2018] [Indexed: 12/15/2022] Open
Abstract
Since their characterization more than five decades ago, gap junctions and their structural proteins-the connexins-have been associated with cancer cell growth. During that period, the accumulation of data and molecular knowledge about this association revealed an apparent contradictory relationship between them and cancer. It appeared that if gap junctions or connexins can down regulate cancer cell growth they can be also implied in the migration, invasion and metastatic dissemination of cancer cells. Interestingly, in all these situations, connexins seem to be involved through various mechanisms in which they can act either as gap-junctional intercellular communication mediators, modulators of signalling pathways through their interactome, or as hemichannels, which mediate autocrine/paracrine communication. This complex involvement of connexins in cancer progression is even more complicated by the fact that their hemichannel function may overlap with other gap junction-related proteins, the pannexins. Despite this complexity, the possible involvements of connexins and pannexins in cancer progression and the elucidation of the mechanisms they control may lead to use them as new targets to control cancer progression. In this review, the involvements of connexins and pannexins in these different topics (cancer cell growth, invasion/metastasis process, possible cancer therapeutic targets) are discussed.
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9
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Obacz J, Avril T, Rubio-Patiño C, Bossowski JP, Igbaria A, Ricci JE, Chevet E. Regulation of tumor-stroma interactions by the unfolded protein response. FEBS J 2017; 286:279-296. [PMID: 29239107 DOI: 10.1111/febs.14359] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 11/16/2017] [Accepted: 12/07/2017] [Indexed: 02/06/2023]
Abstract
The unfolded protein response (UPR) is a conserved adaptive pathway that helps cells cope with the protein misfolding burden within the endoplasmic reticulum (ER). Imbalance between protein folding demand and capacity in the ER leads to a situation called ER stress that is often observed in highly proliferative and secretory tumor cells. As such, activation of the UPR signaling has emerged as a key adaptive mechanism promoting cancer progression. It is becoming widely acknowledged that, in addition to its intrinsic effect on tumor biology, the UPR can also regulate tumor microenvironment. In this review, we discuss how the UPR coordinates the crosstalk between tumor and stromal cells, such as endothelial cells, normal parenchymal cells, and immune cells. In addition, we further describe the involvement of ER stress signaling in the response to current treatments as well as its impact on antitumor immunity mainly driven by immunogenic cell death. Finally, in this context, we discuss the relevance of targeting ER stress/UPR signaling as a potential anticancer approach.
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Affiliation(s)
- Joanna Obacz
- Inserm U1242 'Chemistry, Oncogenesis, Stress & Signaling', Université de Rennes, Rennes, France.,Centre de Lutte Contre le Cancer Eugene Marquis, Rennes, France
| | - Tony Avril
- Inserm U1242 'Chemistry, Oncogenesis, Stress & Signaling', Université de Rennes, Rennes, France.,Centre de Lutte Contre le Cancer Eugene Marquis, Rennes, France
| | | | | | - Aeid Igbaria
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | | | - Eric Chevet
- Inserm U1242 'Chemistry, Oncogenesis, Stress & Signaling', Université de Rennes, Rennes, France.,Centre de Lutte Contre le Cancer Eugene Marquis, Rennes, France
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10
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Roy S, Jiang JX, Li AF, Kim D. Connexin channel and its role in diabetic retinopathy. Prog Retin Eye Res 2017; 61:35-59. [PMID: 28602949 DOI: 10.1016/j.preteyeres.2017.06.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 05/30/2017] [Accepted: 06/02/2017] [Indexed: 12/18/2022]
Abstract
Diabetic retinopathy is the leading cause of blindness in the working age population. Unfortunately, there is no cure for this devastating ocular complication. The early stage of diabetic retinopathy is characterized by the loss of various cell types in the retina, namely endothelial cells and pericytes. As the disease progresses, vascular leakage, a clinical hallmark of diabetic retinopathy, becomes evident and may eventually lead to diabetic macular edema, the most common cause of vision loss in diabetic retinopathy. Substantial evidence indicates that the disruption of connexin-mediated cellular communication plays a critical role in the pathogenesis of diabetic retinopathy. Yet, it is unclear how altered communication via connexin channel mediated cell-to-cell and cell-to-extracellular microenvironment is linked to the development of diabetic retinopathy. Recent observations suggest the possibility that connexin hemichannels may play a role in the pathogenesis of diabetic retinopathy by allowing communication between cells and the microenvironment. Interestingly, recent studies suggest that connexin channels may be involved in regulating retinal vascular permeability. These cellular events are coordinated at least in part via connexin-mediated intercellular communication and the maintenance of retinal vascular homeostasis. This review highlights the effect of high glucose and diabetic condition on connexin channels and their impact on the development of diabetic retinopathy.
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Affiliation(s)
- Sayon Roy
- Departments of Medicine and Ophthalmology, Boston University School of Medicine, Boston, MA, United States.
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
| | - An-Fei Li
- Department of Ophthalmology, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
| | - Dongjoon Kim
- Departments of Medicine and Ophthalmology, Boston University School of Medicine, Boston, MA, United States
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11
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Kirichenko EY, Savchenko AF, Kozachenko DV, Matsionis AE, Logvinov AK. [Ultrastructural characteristics of gap junctions in human glial brain tumors]. Arkh Patol 2017; 79:3-11. [PMID: 28295002 DOI: 10.17116/patol20177913-11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
AIM to conduct an electron microscopic study of intercellular communication in the samples of gemistocytic astrocytoma, oligodendroglioma, and glioblastoma. MATERIAL AND METHODS Surgically resected tumor tissue fragments were fixed in 2.5% glutaraldehyde solution, afterfixed in 1% OsO4 solution, dehydrated, and embedded in epoxy resin. Ultrathin sections were examined using a Jem 1011 electron microscope (Jeol, Japan). RESULTS Solitary and closely spaced gap junctions (GJs) formed by the thin processes that have the ultrastructure of an astroglial processes were identified in the astrocytoma samples. In this case, chemical synapses were noted to be completely absent in gemistocytic astrocytoma and glioblastoma. The identified GJs had a small length and deformed nexuses. The oligodendroglioma samples exhibited intact astroglial processes around the chemical synapses; however, interglial GJs were not found. CONCLUSION The investigation showed the presence of intercellular GJs with some ultrastructural differences in the samples of low- and high-grade astroglial tumors. According to current data, astrocytomic GJs are able to create a stable self-sustaining network that promotes tumor progression and provides resistance to a therapeutic intervention. At the same time, the noticeable reduction in the number of GJs, which is most pronounced in the oligodendroglioma sample, can accelerate tumor cell migration into the surrounding parenchyma. The investigation of GJs should be, of course, continued using a group of a larger number of glial tumors to confirm the intercellular communication features revealed in this study.
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Affiliation(s)
- E Yu Kirichenko
- D.I. Ivanovsky Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
| | - A F Savchenko
- Department of Neurosurgery, City Emergency Medical Care Hospital, Rostov-on-Don, Russia
| | - D V Kozachenko
- Department of Neurosurgery, City Emergency Medical Care Hospital, Rostov-on-Don, Russia
| | - A E Matsionis
- Department of Experimental Pathomorphology and Electron Microscopy, Rostov Regional Postmortem Bureau, Rostov-on-Don, Russia
| | - A K Logvinov
- D.I. Ivanovsky Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
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Localisation Microscopy of Breast Epithelial ErbB-2 Receptors and Gap Junctions: Trafficking after γ-Irradiation, Neuregulin-1β, and Trastuzumab Application. Int J Mol Sci 2017; 18:ijms18020362. [PMID: 28208769 PMCID: PMC5343897 DOI: 10.3390/ijms18020362] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 01/28/2017] [Accepted: 01/30/2017] [Indexed: 12/28/2022] Open
Abstract
In cancer, vulnerable breast epithelium malignance tendency correlates with number and activation of ErbB receptor tyrosine kinases. In the presented work, we observe ErbB receptors activated by irradiation-induced DNA injury or neuregulin-1β application, or alternatively, attenuated by a therapeutic antibody using high resolution fluorescence localization microscopy. The gap junction turnover coinciding with ErbB receptor activation and co-transport is simultaneously recorded. DNA injury caused by 4 Gray of 6 MeV photon γ-irradiation or alternatively neuregulin-1β application mobilized ErbB receptors in a nucleograde fashion—a process attenuated by trastuzumab antibody application. This was accompanied by increased receptor density, indicating packing into transport units. Factors mobilizing ErbB receptors also mobilized plasma membrane resident gap junction channels. The time course of ErbB receptor activation and gap junction mobilization recapitulates the time course of non-homologous end-joining DNA repair. We explain our findings under terms of DNA injury-induced membrane receptor tyrosine kinase activation and retrograde trafficking. In addition, we interpret the phenomenon of retrograde co-trafficking of gap junction connexons stimulated by ErbB receptor activation.
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13
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Krcek R, Latzer P, Adamietz IA, Bühler H, Theiss C. Influence of vascular endothelial growth factor and radiation on gap junctional intercellular communication in glioblastoma multiforme cell lines. Neural Regen Res 2017; 12:1816-1822. [PMID: 29239327 PMCID: PMC5745835 DOI: 10.4103/1673-5374.219030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Glioblastoma multiforme (GBM) is a highly aggressive glial brain tumor with an unfavorable prognosis despite all current therapies including surgery, radiation and chemotherapy. One characteristic of this tumor is a strong synthesis of vascular endothelial growth factor (VEGF), an angiogenesis factor, followed by pronounced vascularization. VEGF became a target in the treatment of GBM, for example with bevacizumab or the tyrosine kinase inhibitor axitinib, which blocks VEGF receptors. To improve patients’ prognosis, new targets in the treatment of GBM are under investigations. The role of gap junctions in GBM remains unknown, but some experimental therapies affect these intercellular channels to treat the tumor. Gap junctions are composed of connexins to allow the transport of small molecules between adjacent cells through gap junctional intercellular communication (GJIC). Based on data derived from astrocytes in former studies, which show that VEGF is able to enhance GJIC, the current study analyzed the effects of VEGF, radiation therapy and VEGF receptor blockade by axitinib on GJIC in human GBM cell lines U-87 and U-251. While VEGF is able to induce GJIC in U-251 cells but not in U-87 cells, radiation enhances GJIC in both cell lines. VEGF receptor blockade by axitinib diminishes radiation induced effects in U-251 partially, while increases GJIC in U-87 cells. Our data indicate that VEGF and radiation are both modifying components of GJIC in pathologic brain tumor tissue.
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Affiliation(s)
- Reinhardt Krcek
- Institute of Anatomy, Department of Cytology, Ruhr-University Bochum, Bochum, North Rhine-Westphalia, Germany
| | - Pauline Latzer
- Institute of Anatomy, Department of Cytology, Ruhr-University Bochum, Bochum, North Rhine-Westphalia, Germany
| | - Irenäus Anton Adamietz
- Department of Radiotherapy and Radio-Oncology, University Medical Centre Marienhospital, Ruhr-University Bochum, Herne, North Rhine-Westphalia, Germany
| | - Helmut Bühler
- Institute for Molecular Oncology, Radio-Biology and Experimental Radiotherapy, University Medical Centre Marienhospital, Ruhr-University Bochum, Herne, North Rhine-Westphalia, Germany
| | - Carsten Theiss
- Institute of Anatomy, Department of Cytology, Ruhr-University Bochum, Bochum, North Rhine-Westphalia, Germany
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14
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Jiang G, Dong S, Yu M, Han X, Zheng C, Zhu X, Tong X. Influence of gap junction intercellular communication composed of connexin 43 on the antineoplastic effect of adriamycin in breast cancer cells. Oncol Lett 2016; 13:857-866. [PMID: 28356970 DOI: 10.3892/ol.2016.5471] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 10/06/2016] [Indexed: 12/15/2022] Open
Abstract
Gap junctions (GJs) serve the principal role in the antineoplastic (cytotoxicity and induced apoptosis) effect of chemical drugs. The aim of the present study was to determine the effect of GJ intercellular communication (GJIC) composed of connexin 43 (Cx43) on adriamycin cytotoxicity in breast cancer cells. Four cell lines (Hs578T, MCF-7, MDA-MB-231 and SK-BR-3) with different degree of malignancy were used in the study. The results of western blotting and immunofluorescence revealed that, in Hs578T and MCF-7 cells, which have a low degree of malignancy, the expression levels of Cx43 and GJIC were higher than those in MDA-MB-231 and SK-BR-3 cells (which have a high degree of malignancy). In Hs578T and MCF-7 cells, where GJ could be formed, the function of GJ was modulated by a pharmacological potentiators [retinoid acid (RA)]/inhibitors [oleamide and 18-α-glycyrrhetinic acid (18-α-GA)] and small interfering RNA (siRNA). In high-density cells (where GJ was formed), enhancement of GJ function by RA increased the cytotoxicity of adriamycin, while inhibition of GJ function by oleamide/18-α-GA and siRNA decreased the cytotoxicity caused by adriamycin. Notably, the modulation of GJ did not affect the survival of cells treated with adriamycin when cells were in low density (no GJ was formed). The present study illustrated the association between GJIC and the antitumor effect of adriamycin in breast cancer cells. The cytotoxicity of adriamycin on breast cancer cells was increased when the function of gap junctions was enhanced.
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Affiliation(s)
- Guojun Jiang
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
| | - Shuying Dong
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
| | - Meiling Yu
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China; Department of Pharmacy, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233004, P.R. China
| | - Xi Han
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
| | - Chao Zheng
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
| | - Xiaoguang Zhu
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
| | - Xuhui Tong
- Faculty of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233030, P.R. China
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15
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Gerardi C, Frassinetti S, Caltavuturo L, Leone A, Lecci R, Calabriso N, Carluccio MA, Blando F, Mita G. Anti-proliferative, anti-inflammatory and anti-mutagenic activities of a Prunus mahaleb L. anthocyanin-rich fruit extract. J Funct Foods 2016. [DOI: 10.1016/j.jff.2016.09.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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16
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Seely D, Mills EJ, Wu P, Verma S, Guyatt GH. The Effects of Green Tea Consumption on Incidence of Breast Cancer and Recurrence of Breast Cancer: A Systematic Review and Meta-analysis. Integr Cancer Ther 2016; 4:144-55. [PMID: 15911927 DOI: 10.1177/1534735405276420] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background: Green tea is widely used by women for the prevention and treatment of breast cancer. The authors aimed to determine the efficacy of green tea ingestion on the risk of breast cancer development and the risk of breast cancer recurrence. Methods: The authors conducted a systematic review and meta-analyses of observational studies from systematic searches of 8 electronic data sources and contact with authors. They included studies assessing breast cancer incidence and recurrence. Results from cohort studies and case-control studies were pooled separately using a random effects model with testing of a priori hypotheses to explain heterogeneity. Results: The pooled relative risk (RR) of developing breast cancer for the highest levels of green tea consumption in cohort studies was 0.89 (95% confidence interval [CI], 0.71-1.1; P= .28; I2= 0%), and in case control studies, the odds ratio was 0.44 (95% CI, 0.14-1.31; P= .14; I2= 47%). The pooled RR of cohort studies for breast cancer recurrence in all stages was 0.75 (95% CI, 0.47-1.19; P= .22; I2= 37%). A subgroup analysis of recurrence in stage I and II disease showed a pooled RR in cohort studies of 0.56 (95% CI, 0.38-0.83; P= .004; I2= 0%). Dose-response relationships were evident in only 3 of the 7 studies. Conclusion: To date, the epidemiological data indicates that consumption of 5 or more cups of green tea a day shows a non-statistically significant trend towards the prevention of breast cancer development. Evidence indicates that green tea consumption may possibly help prevent breast cancer recurrence in early stage (I and II) cancers. However, conclusions as to the potential therapeutic application of green tea are currently impossible to make due to the small number of studies conducted, the lack of any clinical trial evidence, the lack of a consistent dose-response relationship, and the potential for interaction with standard care.
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Affiliation(s)
- Dugald Seely
- Department of Clinical Epidemiology, Canadian College of Naturopathic Medicine, Toronto, Ontario, Canada.
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17
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Babica P, Čtveráčková L, Lenčešová Z, Trosko JE, Upham BL. Chemopreventive Agents Attenuate Rapid Inhibition of Gap Junctional Intercellular Communication Induced by Environmental Toxicants. Nutr Cancer 2016; 68:827-37. [PMID: 27266532 DOI: 10.1080/01635581.2016.1180409] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Altered gap junctional intercellular communication (GJIC) has been associated with chemical carcinogenesis, where both chemical tumor promoters and chemopreventive agents (CPAs) are known to conversely modulate GJIC. The aim of this study was to investigate whether attenuation of chemically inhibited GJIC represents a common outcome induced by different CPAs, which could be effectively evaluated using in vitro methods. Rat liver epithelial cells WB-F344 were pretreated with a CPA for either 30 min or 24 h, and then exposed to GJIC-inhibiting concentration of a selected tumor promoter or environmental toxicant [12-O-tetradecanoylphorbol-13-acetate (TPA), lindane, fluoranthene, 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT), perfluorooctanoic acid (PFOA), or pentachlorophenol]. Out of nine CPAs tested, quercetin and silibinin elicited the most pronounced effects, preventing the dysregulation of GJIC by all the GJIC inhibitors, but DDT. Metformin and curcumin attenuated the effects of three GJIC inhibitors, whereas the other CPAs prevented the effects of two (diallyl sulfide, emodin) or one (indole-3-carbinol, thymoquinone) GJIC inhibitor. Significant attenuation of chemically induced inhibition of GJIC was observed in 27 (50%) out of 54 possible combinations of nine CPAs and six GJIC inhibitors. Our data demonstrate that in vitro evaluation of GJIC can be used as an effective screening tool for identification of chemicals with potential chemopreventive activity.
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Affiliation(s)
- Pavel Babica
- a Department of Experimental Phycology and Ecotoxicology , Institute of Botany of the ASCR , Brno , Czech Republic.,b RECETOX - Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University , Brno , Czech Republic
| | - Lucie Čtveráčková
- a Department of Experimental Phycology and Ecotoxicology , Institute of Botany of the ASCR , Brno , Czech Republic.,b RECETOX - Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University , Brno , Czech Republic
| | - Zuzana Lenčešová
- a Department of Experimental Phycology and Ecotoxicology , Institute of Botany of the ASCR , Brno , Czech Republic.,b RECETOX - Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University , Brno , Czech Republic
| | - James E Trosko
- c Department of Pediatrics and Human Development & Institute for Integrative Toxicology, Michigan State University , Michigan , USA
| | - Brad L Upham
- c Department of Pediatrics and Human Development & Institute for Integrative Toxicology, Michigan State University , Michigan , USA
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18
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Abstract
Communication among cells via direct cell-cell contact by connexin gap junctions, or between cell and extracellular environment via pannexin channels or connexin hemichannels, is a key factor in cell function and tissue homeostasis. Upon malignant transformation in different cancer types, the dysregulation of these connexin and pannexin channels and their effect in cellular communication, can either enhance or suppress tumorigenesis and metastasis. In this review, we will highlight the latest reports on the role of the well characterized connexin family and its ability to form gap junctions and hemichannels in cancer. We will also introduce the more recently discovered family of pannexin channels and our current knowledge about their involvement in cancer progression.
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Affiliation(s)
- Jean X Jiang
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Silvia Penuela
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, N6A5C1, Canada.
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19
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Kirichenko EY, Zhukova GV, Grigorov SV, Grankina AO, Atmachidi DP. [The expression of connexin 36 and some neuroglial antigens in human brain astrocytic tumors of different grades]. Arkh Patol 2015; 77:23-29. [PMID: 26226778 DOI: 10.17116/patol201577323-29] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
OBJECTIVE To reveal the expression of neuronal connexin 36 (Cx36) in gliomas and then to analyze the ratio of expression of Cx36 to that of neuroglial antigens (synaptophysin, neurofilaments, and glial fibrillary acidic protein). MATERIAL AND METHODS Varying grade human glioma samples and tumor-adjacent tissue fragments were used for immunohistochemical examination. RESULTS A procedure for immunohistochemical detection of Cx36 in brain tissue was tried out. It was shown that the decreased level of the examined neuronal proteins was accompanied by the impaired coexpression of synaptophysin/neurofilaments and Cx36 in the series of astrocytomas--anaplastic astrocytomas--glioblastomas. The immunohistochemical heterogeneity of glioblastomas was found. CONCLUSION The findings suggest that it is promising to include anti-Cx36 antibodies in immunohistochemical panels when examining brain tumors. Data on the lower levels of the examined neuronal proteins, on the specific features of their distribution and impaired coexpression expand their idea on the pathogenesis of a brain tumor process and determine an area for further investigations.
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Affiliation(s)
- E Yu Kirichenko
- Laboratory of Functional Neurobiology and Electron Microscopy, A.B. Kogan Research Institute of Neurocybernetics, Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don
| | - G V Zhukova
- Rostov Research Institute of Oncology, Ministry of Health of the Russian Federation, Rostov-on-Don
| | - S V Grigorov
- Rostov Research Institute of Oncology, Ministry of Health of the Russian Federation, Rostov-on-Don
| | - A O Grankina
- Laboratory of Functional Neurobiology and Electron Microscopy, A.B. Kogan Research Institute of Neurocybernetics, Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don
| | - D P Atmachidi
- Rostov Research Institute of Oncology, Ministry of Health of the Russian Federation, Rostov-on-Don
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20
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Aasen T. Connexins: junctional and non-junctional modulators of proliferation. Cell Tissue Res 2014; 360:685-99. [PMID: 25547217 DOI: 10.1007/s00441-014-2078-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 11/14/2014] [Indexed: 12/11/2022]
Abstract
Mounting evidence indicates that dysregulation of gap junctions and their structural subunits-connexins-often occurs in, and sometimes causes, a variety of proliferative disorders, including cancer. Connexin-mediated regulation of cell proliferation is complex and may involve modulation of gap junction intercellular communication (GJIC), hemichannel signalling, or gap junction-independent paths. However, the exact mechanisms linking connexins to proliferation remain poorly defined and a number of contradictory studies report both pro- and anti-proliferative effects, effects that often depend on the cell or tissue type or the microenvironment. The present review covers junctional and non-junctional regulation of proliferation by connexins, with a particular emphasis on their association with cancer.
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Affiliation(s)
- Trond Aasen
- Molecular Pathology Group, Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Passeig Vall d'Hebron 119-129, Barcelona, 08035, Spain,
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21
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Kelsey L, Katoch P, Ray A, Mitra S, Chakraborty S, Lin MF, Mehta PP. Vitamin D3 regulates the formation and degradation of gap junctions in androgen-responsive human prostate cancer cells. PLoS One 2014; 9:e106437. [PMID: 25188420 PMCID: PMC4154685 DOI: 10.1371/journal.pone.0106437] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 08/06/2014] [Indexed: 11/19/2022] Open
Abstract
1α-25(OH)2 vitamin D3 (1-25D), an active hormonal form of Vitamin D3, is a well-known chemopreventive and pro-differentiating agent. It has been shown to inhibit the growth of several prostate cancer cell lines. Gap junctions, formed of proteins called connexins (Cx), are ensembles of cell-cell channels, which permit the exchange of small growth regulatory molecules between adjoining cells. Cell-cell communication mediated by gap junctional channels is an important homeostatic control mechanism for regulating cell growth and differentiation. We have investigated the effect of 1-25D on the formation and degradation of gap junctions in an androgen-responsive prostate cancer cell line, LNCaP, which expresses retrovirally-introduced Cx32. Connexin32 is expressed by the luminal and well-differentiated cells of normal prostate and prostate tumors. Our results document that 1-25D enhances the expression of Cx32 and its subsequent assembly into gap junctions. Our results further show that 1-25D prevents androgen-regulated degradation of Cx32, post-translationally, independent of androgen receptor (AR)-mediated signaling. Finally, our findings document that formation of gap junctions sensitizes Cx32-expressing LNCaP cells to the growth inhibitory effects of 1-25D and alters their morphology. These findings suggest that the growth-inhibitory effects of 1-25D in LNCaP cells may be related to its ability to modulate the assembly of Cx32 into gap junctions.
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Affiliation(s)
- Linda Kelsey
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Parul Katoch
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Anuttoma Ray
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Shalini Mitra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Souvik Chakraborty
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Ming-Fong Lin
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Parmender P. Mehta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
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22
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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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23
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Yu ML, Zhang CL, Yuan DD, Tong XH, Tao L. Panax notoginseng saponins enhances the cytotoxicity of cisplatin via increasing gap junction intercellular communication. Biol Pharm Bull 2012; 35:1230-7. [PMID: 22863918 DOI: 10.1248/bpb.b110535] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Panax Notoginseng Saponins (PNS) have been well known to have anti-tumor activity and enhance cytotoxicity of some cancer chemotherapy agents, but the mechanisms underlying these effects are still unknown. This study investigates the effect of PNS on cytotoxicity of cisplatin and the relationship between this effect and the modulation of gap junctions (GJ) function by PNS in a transfected cell line. The cytotoxicity of cisplatin (0.25-1 µg/mL) was increased in the presence of GJ. Inhibition of gap junction by either GJ blocker or interception of Connexin (Cx) expression decreased the cytotoxicity of cisplatin. Increasing GJ function enhanced cytotoxicity of cisplatin, only in the cells with functional GJ. PNS (50-200 µg/mL) significantly enhanced cisplatin cytotoxicity, but this effect required functional gap junctions between the cells. Exposure of the cells to PNS (50-200 µg/mL) for 4 h leads to a significant enhance in dye coupling of GJ in a dose-dependent manner. These results suggest that PNS increases the cytotoxicity of cisplatin through enhancement of GJ activity.
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Affiliation(s)
- Mei-ling Yu
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, P. R. China
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24
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Bijnsdorp IV, Rozendaal L, van Moorselaar RJA, Geldof AA. A predictive role for noncancerous prostate cells: low connexin-26 expression in radical prostatectomy tissues predicts metastasis. Br J Cancer 2012; 107:1963-8. [PMID: 23169284 PMCID: PMC3516687 DOI: 10.1038/bjc.2012.500] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Background: It is important to identify markers that predict whether prostate cancer will metastasise. The adjacent noncancerous cells (influenced by the tumour cells) may also express potential markers. The objective of this study was to determine the influence of cancer cells on noncancerous cells and to assess the value of the cell-communication protein connexin-26 (Cx26) as a marker to predict the development of metastasis. Methods: The effect of conditioned medium (CM) from PrCa cells on in vitro noncancerous cell proliferation, migration and invasion and Cx26 expression was determined. Connexin-26 expression was investigated in prostatectomy tissues from 51 PrCa patients by immunohistochemistry and compared with various clinicopathological parameters. Results: Proliferation, migration and invasion of noncancerous cells were influenced by CM from the PrCa cell lines. Importantly, a clear relation was found between low Cx26 expression in the noncancerous tissue in prostatectomy sections and the risk of development of metastasis (P<0.0002). Kaplan–Meier analysis showed a relation between low Cx26 expression in noncancerous tissues and time to biochemical recurrence (P=0.0002). Conclusion: Measuring Cx26 expression in the adjacent noncancerous tissues (rather than cancer tissues) of prostatectomy sections could help to identify high-risk patients who may benefit from adjuvant therapy to decrease the risk of metastasis.
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Affiliation(s)
- I V Bijnsdorp
- Department of Urology, VU University Medical Center, De Boelelaan 1117 4F12, Amsterdam 1081 HV, The Netherlands.
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25
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Gap junctions and non-neoplastic liver disease. J Hepatol 2012; 57:655-62. [PMID: 22609308 DOI: 10.1016/j.jhep.2012.02.036] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 02/15/2012] [Accepted: 02/17/2012] [Indexed: 12/30/2022]
Abstract
Because of their critical role as goalkeepers of hepatic homeostasis, gap junctions are frequent targets in liver disease. This concept has been demonstrated on many occasions in the light of hepatocarcinogenesis. Relatively little focus has been put on the fate of gap junctions in other liver pathologies, including hepatitis, liver fibrosis and cirrhosis, cholestasis and hepatic ischemia and reperfusion injury. The present paper provides an in-depth description of the multiple changes in expression, localization and function of connexins, the molecular constituents of gap junctions. The use of connexins as biomarkers and therapeutic targets in liver disease is also illustrated.
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26
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Kelsey L, Katoch P, Johnson KE, Batra SK, Mehta PP. Retinoids regulate the formation and degradation of gap junctions in androgen-responsive human prostate cancer cells. PLoS One 2012; 7:e32846. [PMID: 22514600 PMCID: PMC3326013 DOI: 10.1371/journal.pone.0032846] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 01/31/2012] [Indexed: 12/13/2022] Open
Abstract
The retinoids, the natural or synthetic derivatives of Vitamin A (retinol), are essential for the normal development of prostate and have been shown to modulate prostate cancer progression in vivo as well as to modulate growth of several prostate cancer cell lines. 9-cis-retinoic acid and all-trans-retinoic acid are the two most important metabolites of retinol. Gap junctions, formed of proteins called connexins, are ensembles of intercellular channels that permit the exchange of small growth regulatory molecules between adjoining cells. Gap junctional communication is instrumental in the control of cell growth. We examined the effect of 9-cis-retinoic acid and all-trans retinoic acid on the formation and degradation of gap junctions as well as on junctional communication in an androgen-responsive prostate cancer cell line, LNCaP, which expressed retrovirally introduced connexin32, a connexin expressed by the luminal cells and well-differentiated cells of prostate tumors. Our results showed that 9-cis-retinoic acid and all-trans retinoic acid enhanced the assembly of connexin32 into gap junctions. Our results further showed that 9-cis-retinoic acid and all-trans-retinoic acid prevented androgen-regulated degradation of gap junctions, post-translationally, independent of androgen receptor mediated signaling. Finally, our findings showed that formation of gap junctions sensitized connexin32-expressing LNCaP cells to the growth modifying effects of 9-cis-retinoic acid, all-trans-retinoic acid and androgens. Thus, the effects of retinoids and androgens on growth and the formation and degradation of gap junctions and their function might be related to their ability to modulate prostate growth and cancer.
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Affiliation(s)
| | | | | | | | - Parmender P. Mehta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
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27
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Bernzweig J, Heiniger B, Prasain K, Lu J, Hua DH, Nguyen TA. Anti-breast cancer agents, quinolines, targeting gap junction. Med Chem 2012; 7:448-53. [PMID: 21801150 DOI: 10.2174/157340611796799131] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 05/05/2011] [Indexed: 11/22/2022]
Abstract
Cancer cells exhibit many defects in cell communication that contribute to the loss of tissue homeostasis (excess cell proliferation, invasion, and metastasis). The process of cancer formation causes a disruption in cell homeostasis, affecting the ability to respond to extracellular signals, as well as triggering some intracellular events which alter gap junctional intercellular communication (GJIC). Previous research has shown that the first two generations of substituted quinolines have anti-cancer effects in human breast cancer cells. This report presents the synthesis and bioactivities of third generation substituted quinolines. Scrape load/dye transfer studies showed that 100 nM of PQ15, a third generation substituted quinoline, causes a 4.5-fold increase of gap junction activity in T47D breast cancer cells. Furthermore, a significant decrease of cell proliferation and viability was observed in the presence of 200 nM PQ15 compared to control. The expression of α-survivin was reduced to <40% in the treatment of 200 nM PQ15 compared to solvent alone. Alpha-survivin expression is upregulated in human cancers and associated with resistance to chemotherapy, suggesting that α-survivin prolongs the survival of cancer cells. Thus, it has been shown that substituted quinolines stimulate gap junction activity, decrease alpha survivin expression, and subsequently inhibit cancer cell growth. Our findings demonstrate that PQ15 has a promising role in exerting anti-cancer activity in human breast cancer cells.
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Affiliation(s)
- Julie Bernzweig
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA
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28
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Ding Y, Nguyen TA. Gap Junction Enhancer Potentiates Cytotoxicity of Cisplatin in Breast Cancer Cells. ACTA ACUST UNITED AC 2012; 4:371-378. [PMID: 25045421 DOI: 10.4172/1948-5956.1000170] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cisplatin is one of the most widely used anti-cancer drugs due to its ability to damage DNA and induce apoptosis. However, increasing reports of side effects and drug resistance indicate the limitation of cisplatin in cancer therapeutics. Recent studies showed that inhibition of gap junctions diminishes the cytotoxic effect and contributes to drug resistance. Therefore, identification of molecules that counteract gap junctional inhibition without decreasing the anti-cancer effect of cisplatin could be used in combinational treatment, potentiating cisplatin efficacy and preventing resistance. This study investigates the effects of combinational treatment of cisplatin and PQ1, a gap junction enhancer, in T47D breast cancer cells. Our results showed that combinational treatment of PQ1 and cisplatin increased gap junctional intercellular communication (GJIC) as well as expressions of connexins (Cx26, Cx32 and Cx43), and subsequently decreased cell viability. Ki67, a proliferation marker, was decreased by 75% with combinational treatment. Expressions of pro-apoptotic factors (cleaved caspase-3/-8/-9 and bax) were increased by the combinational treatment with PQ1 and cisplatin; whereas, the pro-survival factor, bcl-2, was decreased by the combinational treatment. Our study demonstrates for the first time that the combinational treatment with gap junction enhancers can counteract cisplatin induced inhibition of gap junctional intercellular communication and reduction of connexin expression, thereby increasing the efficacy of cisplatin in cancer cells.
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Affiliation(s)
- Ying Ding
- Department of Biochemistry, Kansas State University, Manhattan, Kansas, USA
| | - Thu Annelise Nguyen
- Department of Diagnostic Medicine/ Pathobiology, Kansas State University, Manhattan, Kansas, USA
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Huong LD, Shim JH, Choi KH, Shin JA, Choi ES, Kim HS, Lee SJ, Kim SJ, Cho NP, Cho SD. Effect of β-phenylethyl isothiocyanate from cruciferous vegetables on growth inhibition and apoptosis of cervical cancer cells through the induction of death receptors 4 and 5. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:8124-8131. [PMID: 21702500 DOI: 10.1021/jf2006358] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Cruciferous vegetables have been shown to have the possibility to protect against multistep carcinogenesis. β-Phenylethyl isothiocyanate (PEITC) is one component of these vegetables demonstrated to help fight many types of cancer. The present study examined the apoptotic effects of PEITC and its molecular mechanism in human cervical cancer cell lines (HEp-2 and KB). PEITC induced apoptosis to inhibit cell proliferation. According to the protein chip assay, PEITC increased the expression of the death receptors (DR4 and DR5) and cleaved caspase-3 compared to the DMSO treatment group. PEITC also induced caspase-8 and truncated BID. PEITC down-regulated the phosphorylation of extracellular-related kinase (ERK)1/2, whereas neither phospho-c-Jun NH(2)-terminal kinases (JNK) nor phospho-p38 MAPK was changed. The role of ERK in PEITC-induced apoptosis was also investigated using MEK inhibitor (PD98059). PD98059 increased the expression of DR4 and DR5, activated caspase-3, and cleaved PARP. In addition, PEITC decreased the phosphorylation of MEK. Therefore, the apoptotic mechanism of PEITC in cervical cancer cells involves the induction of DR4 and DR5 through the inactivation of ERK and MEK.
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Affiliation(s)
- Le Diem Huong
- Department of Oral Pathology, School of Dentistry, Institute of Oral Bioscience, Brain Korea 21, Chonbuk National University, Jeonju, Republic of Korea
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Novel Anticancer Platinum(IV) Complexes with Adamantylamine: Their Efficiency and Innovative Chemotherapy Strategies Modifying Lipid Metabolism. Met Based Drugs 2011; 2008:417897. [PMID: 18414587 PMCID: PMC2291354 DOI: 10.1155/2008/417897] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 10/08/2007] [Accepted: 10/18/2007] [Indexed: 11/18/2022] Open
Abstract
The impressive impact of cisplatin on cancer on one side and severe side effects, as well as the development of drug resistance during treatment on the other side, were the factors motivating scientists to design and synthesize new more potent analogues lacking disadvantages of cisplatin. Platinum(IV) complexes represent one of the perspective groups of platinum-based drugs. In this review, we summarize recent findings on both in vitro and in vivo effects of platinum(IV) complexes with adamantylamine. Based on a literary overview of the mechanisms of activity of platinum-based cytostatics, we discuss opportunities for modulating the effects of novel platinum complexes through interactions with apoptotic signaling pathways and with cellular lipids, including modulations of the mitochondrial cell death pathway, oxidative stress, signaling of death ligands, lipid metabolism/signaling, or intercellular communication. These approaches might significantly enhance the efficacy of both novel and established platinum-based cytostatics.
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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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Hsu A, Bray TM, Ho E. Anti-inflammatory activity of soy and tea in prostate cancer prevention. Exp Biol Med (Maywood) 2010; 235:659-67. [PMID: 20511670 PMCID: PMC4125123 DOI: 10.1258/ebm.2010.009335] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Prostate cancer is the leading cancer-related cause of death for men in the USA. Prostate cancer risk is significantly lower in Asian countries compared with the USA, which has prompted interest in the potential chemo-preventive action of soy and green tea that are more predominant in Asian diets. It has been proposed that chronic inflammation is a major risk factor of prostate cancer, acting as both an initiator and promoter. Specifically, the nuclear factor-kappa B (NF-kappaB) pathway has been implicated as an important mediator between chronic inflammation, cell proliferation and prostate cancer. Dietary factors that inhibit inflammation and NF-kappaB may serve as effective chemo-preventive agents. Recent studies have demonstrated that soy and green tea have anti-inflammatory properties, and may have the potential to block the inflammatory response during cancer progression. This minireview discusses the relationship between chronic inflammation and prostate cancer, emphasizing on the significance of NF-kappaB, and further explores the anti-inflammatory effects of soy and green tea. Finally, we propose that dietary strategies that incorporate these bioactive food components as whole foods may be a more effective means to target pathways that contribute to prostate cancer development.
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Affiliation(s)
- Anna Hsu
- Department of Nutrition and Exercise Sciences, 103 Milam Hall, Oregon State University, Corvallis, OR 97331, USA
| | - Tammy M Bray
- Department of Nutrition and Exercise Sciences, 103 Milam Hall, Oregon State University, Corvallis, OR 97331, USA
- Linus Pauling Institute, 571 Weniger Hall, Oregon State University, Corvallis, OR 97331, USA
| | - Emily Ho
- Department of Nutrition and Exercise Sciences, 103 Milam Hall, Oregon State University, Corvallis, OR 97331, USA
- Linus Pauling Institute, 571 Weniger Hall, Oregon State University, Corvallis, OR 97331, USA
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Huang T, Zhu Y, Fang X, Chi Y, Kitamura M, Yao J. Gap junctions sensitize cancer cells to proteasome inhibitor MG132-induced apoptosis. Cancer Sci 2010; 101:713-21. [PMID: 19961488 PMCID: PMC11159102 DOI: 10.1111/j.1349-7006.2009.01421.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Proteasome inhibition is a promising approach for cancer therapy. However, the mechanisms involved have not been fully elucidated. Gap junctions play important roles in the regulation of tumor cell phenotypes and mediation of the bystander effect in cancer therapy. Because the degradation of gap junction proteins involves the proteasome, we speculated that altered gap junctions might contribute to the antitumor activities of proteasome inhibition. Incubation of Hepa-1c1c7 cells with the proteasome inhibitor MG132 elevated the levels of gap junction protein connexin 43 (Cx43) and promoted gap junctional intercellular communication. This was associated with a marked accumulation of ubiquitylated Cx43 and a significantly decreased rate of Cx43 degradation. The elevated Cx43 contributed to MG132-induced cell apoptosis. This is shown by the observations that: (i) overexpression of Cx43 in the gap junction-deficient LLC-PK1 cells rendered them vulnerable to MG132-elicited cell injury; (ii) fibroblasts derived from Cx43-null mice were more resistant to MG-132 compared with Cx43 wild-type control; and (iii) the gap junction inhibitor flufenamic acid significantly attenuated cell damage caused by MG132 in Hepa-1c1c7 cells. Further studies demonstrated that MG132 activates endoplasmic reticulum stress. Exposure of cells to the endoplasmic reticulum stress inducers thapsigargin and tunicamycin also led to cell apoptosis, which was modulated by Cx43 levels in a way similar to MG132. These results suggested that elevated Cx43 sensitizes cells to MG132-induced cell apoptosis. Regulation of gap junctions could be an important mechanism behind the antitumor activities of proteasome inhibitors.
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Affiliation(s)
- Tao Huang
- Department of Molecular Signaling, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan
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He B, Tong X, Wang L, Wang Q, Ye H, Liu B, Hong X, Tao L, Harris AL. Tramadol and flurbiprofen depress the cytotoxicity of cisplatin via their effects on gap junctions. Clin Cancer Res 2009; 15:5803-10. [PMID: 19723651 DOI: 10.1158/1078-0432.ccr-09-0811] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Cancer patients are often concurrently treated with analgesics and antineoplastic drugs, yet the influence of analgesic agents on therapeutic activity of antineoplastic drugs is largely unexplored. This study investigates the effects of three commonly used analgesics, which produce analgesia by different mechanisms, on cytotoxicity induced by cisplatin, a widely used antitumor agent, and the relation between those effects and modulation of gap junction function by the analgesics. EXPERIMENTAL DESIGN The role of gap junctions in the modulation of cisplatin toxicity is explored by manipulation of connexin expression, and gap junction presence and function, using clinically relevant concentrations of the analgesics and cisplatin. RESULTS Short-term exposure of transformed cells to cisplatin reduced the clonogenic survival in low-density cultures (without gap junction formation) and in high density (with gap junction formation), but the toxic effect was greater at high density. In the absence of connexin expression or with block of connexin channels, cell density had no effect on cisplatin toxicity. Tramadol and flurbiprofen, but not morphine, significantly reduced cisplatin cytotoxicity, but this effect required functional gap junctions between the cells. Tramadol and flurbiprofen inhibited dye-coupling through gap junctions, but morphine did not. CONCLUSIONS The results suggest that the density dependence of cisplatin toxicity is mediated by gap junctions. They further indicate that tramadol and flurbiprofen depress cisplatin cytotoxicity through inhibition of gap junction activity, and more generally, that agents that depress junctional communication can counteract the effects of antitumor agents.
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Affiliation(s)
- Bo He
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, People's Republic of China
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Hattis D, Chu M, Rahmioglu N, Goble R, Verma P, Hartman K, Kozlak M. A preliminary operational classification system for nonmutagenic modes of action for carcinogenesis. Crit Rev Toxicol 2009; 39:97-138. [PMID: 19009457 DOI: 10.1080/10408440802307467] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This article proposes a system of categories for nonmutagenic modes of action for carcinogenesis. The classification is of modes of action rather than individual carcinogens, because the same compound can affect carcinogenesis in more than one way. Basically, we categorize modes of action as: (1) co-initiation (facilitating the original mutagenic changes in stem and progenitor cells that start the cancer process) (e.g. induction of activating enzymes for other carcinogens); (2) promotion (enhancing the relative growth vs differentiation/death of initiated clones (e.g. inhibition of growth-suppressing cell-cell communication); (3) progression (enhancing the growth, malignancy, or spread of already developed tumors) (e.g. suppression of immune surveillance, hormonally mediated growth stimulation for tumors with appropriate receptors by estrogens); and (4) multiphase (e.g., "epigenetic" silencing of tumor suppressor genes). A priori, agents that act at relatively early stages in the process are expected to manifest greater relative susceptibility in early life, whereas agents that act via later stage modes will tend to show greater susceptibility for exposures later in life.
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Affiliation(s)
- D Hattis
- George Perkins Marsh Institute, Clark University, Worcester, Massachusetts, USA
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Lee KM, Kwon JY, Lee KW, Lee HJ. Ascorbic acid 6-palmitate suppresses gap-junctional intercellular communication through phosphorylation of connexin 43 via activation of the MEK-ERK pathway. Mutat Res 2009; 660:51-56. [PMID: 19026667 DOI: 10.1016/j.mrfmmm.2008.10.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 10/01/2008] [Accepted: 10/14/2008] [Indexed: 05/27/2023]
Abstract
Although the health benefits of dietary antioxidants have been extensively studied, their potential negative effects remain unclear. L-Ascorbic acid 6-palmitate (AAP), a synthetic derivative of ascorbic acid (AA), is widely used as an antioxidant and preservative in foods, vitamins, drugs, and cosmetics. Previously, we found that AA exerted an antitumor effect by protecting inhibition of gap-junctional intercellular communication (GJIC), which is closely associated with tumor progression. In this study, we examined whether AAP, an amphipathic derivative of AA, has chemopreventive effects using a GJIC model. AAP and AA exhibited dose-dependent free radical-scavenging activities and inhibited hydrogen peroxide (H(2)O(2))-induced intracellular reactive oxygen species (ROS) production in normal rat liver epithelial cells. Unexpectedly, however, AAP did not protect against the inhibition of GJIC induced by H(2)O(2); instead, it inhibited GJIC synergistically with H(2)O(2). AAP inhibited GJIC in a dose-dependent and reversible manner. This inhibitory effect was not due to the conjugated lipid structure of AAP, as treatment with palmitic acid alone failed to inhibit GJIC under the same conditions. The inhibition of GJIC by AAP was restored in the presence of mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEK) inhibitor U0126, but not in the presence of other signal inhibitors and antioxidant (PKC inhibitors, EGFR inhibitor, NADPH oxidase inhibitor, catalase, vitamin E, or AA), indicating the critical involvement of MEK signaling in the GJIC inhibitory activity of AAP. Phosphorylation of ERK and connexin 43 (Cx43) was observed following AAP treatment, and this was reversed by U0126. These results suggest that the AAP-induced inhibition of GJIC is mediated by the phosphorylation of Cx43 via activation of the MEK-ERK pathway. Taken together, our results indicate that AAP has a potent carcinogenic effect, and that the influence of dietary antioxidants on carcinogenesis may be paradoxical.
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Affiliation(s)
- Kyung Mi Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Republic of Korea
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The regulation of the gap junction of human mesenchymal stem cells through the internalization of quantum dots. Biomaterials 2009; 30:1937-46. [PMID: 19135246 DOI: 10.1016/j.biomaterials.2008.12.039] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 12/16/2008] [Indexed: 01/21/2023]
Abstract
The delivery mechanism of CdSe/ZnS quantum dots (QDs) into cells was previously found to critically determine the biocompatibility of QDs to human adult mesenchymal stem cells, but the associated mechanism remained unknown. The present study tried to establish a link between the above phenomenon and the change in gap junction upon QD internalization. By comparing Pep-1- and PolyFect-mediated QD internalizations, the connexin 43 (Cx43)-mediated gap junction intercellular communication (GJIC) of human adipose-derived adult stem cells was investigated in monolayer and in three-dimensional (3D) culture (alginate hollow spheres). The latter system offered cells more mobility, which was more similar as in vivo. The results showed that Pep-1-coated QDs, which escaped from the endo-/lysosome degradation, could activate the F-actin assembly and the ERK-dependent phosphorylation of Cx43. The consequence was a reduction in Cx43-mediated GJIC. When the cells were grown in high density 3D alginate hollow spheres instead of in monolayer, the decrease of GJIC caused by the QD internalization was restored. These results indicated that the adaptability in QDs-mediated regulation of GJIC with different delivery coatings depended on the culture systems. The study also suggested that the regulation of gap junction may play a key role in QD cytotoxicity.
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Gakhar G, Ohira T, Shi A, Hua DH, Nguyen TA. Antitumor effect of substituted quinolines in breast cancer cells. Drug Dev Res 2008. [DOI: 10.1002/ddr.20281] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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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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Leone S, Fiore M, Lauro MG, Pino S, Cornetta T, Cozzi R. Resveratrol and X rays affect gap junction intercellular communications in human glioblastoma cells. Mol Carcinog 2008; 47:587-98. [DOI: 10.1002/mc.20416] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Jang T, Sathy B, Hsu YH, Merchant M, Recht B, Chang C, Recht L. A distinct phenotypic change in gliomas at the time of magnetic resonance imaging detection. J Neurosurg 2008; 108:782-90. [DOI: 10.3171/jns/2008/108/4/0782] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Although gliomas remain refractory to treatment, it is not clear whether this characteristic is fixed at the time of its origin or develops later. The authors have been using a model of neurocarcinogenesis to determine whether a time exists during a glioma's evolution during which it is detectable but still curable, thus providing a justification for exploring the clinical merits of an early detection and treatment strategy. The authors recently reported the presence of 2 distinct cellular subsets, 1 expressing nestin and the other both glial fibrillary acidic protein (GFAP) and osteopontin (OPN), within all examined gliomas that developed after in utero exposure to ethylnitrosourea.
Methods
In this study, the authors used magnetic resonance (MR) imaging to assess when these 2 subpopulations appeared during glioma evolution.
Results
Using T2-weighted and diffusion-weighted MR imaging, the authors observed that gliomas grew exponentially once detected at rates that were location-dependent. Despite large differences in growth rates, however, they determined by correlating histochemistry with imaging in a second series of animals, that all lesions initially detected on T2-weighted images contained both subsets of cells. In contrast, lesions containing only nestin-positive cells, which appeared on average 40 days before detection on MR images, were not detected.
Conclusions
The sequential appearance of first the nestin-positive cells followed several weeks later by those expressing GFAP/OPN suggests that all gliomas arise through common early steps in this model. Furthermore, the authors hypothesize that the expression of OPN, a molecule associated with cancer aggressiveness, at the time of T2-weighted detection signals a time during glioma development when the lesion becomes refractory to treatment.
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Affiliation(s)
- Taichang Jang
- 1Department of Neurology, Stanford University Medical School, Stanford, California
| | - Binulal Sathy
- 2Institute of Biomedical Science, Academia Sinica, Nan-Kan, Taipei, Taiwan; and
| | - Yi-Hua Hsu
- 2Institute of Biomedical Science, Academia Sinica, Nan-Kan, Taipei, Taiwan; and
| | - Milton Merchant
- 1Department of Neurology, Stanford University Medical School, Stanford, California
| | - Benjamin Recht
- 3Media Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Chen Chang
- 2Institute of Biomedical Science, Academia Sinica, Nan-Kan, Taipei, Taiwan; and
| | - Lawrence Recht
- 1Department of Neurology, Stanford University Medical School, Stanford, California
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Vinken M, Henkens T, De Rop E, Fraczek J, Vanhaecke T, Rogiers V. Biology and pathobiology of gap junctional channels in hepatocytes. Hepatology 2008; 47:1077-88. [PMID: 18058951 DOI: 10.1002/hep.22049] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The present review provides the state of the art of the current knowledge concerning gap junctional channels and their roles in liver functioning. In the first part, we summarize some relevant biochemical properties of hepatic gap junctional channels, including their structure and regulation. In the second part, we discuss the involvement of gap junctional channels in the occurrence of liver cell growth, liver cell differentiation, and liver cell death. We further exemplify their relevance in hepatic pathophysiology. Finally, a number of directions for future liver gap junctional channel research are proposed, and the up-regulation of gap junctional channel activity as a novel strategy in (liver) cancer therapy is illustrated.
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Affiliation(s)
- Mathieu Vinken
- Department of Toxicology, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
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Abstract
Gap junctions that allow the direct communication between cytoplasmic compartments of neighboring cells are present in a variety of tissues and organs and play pivotal roles in a wide range of physiological processes. In the ovary, gap junctions consist mainly of connexin (Cx) 43 and Cx37, and their indispensable role in regulating folliculogenesis and oogenesis is well established. The ovarian Cx43 is regulated by gonadotropins at the transcriptional, translational and post-translational levels whereas the regulation of the ovarian Cx37 is yet unknown. In addition to their involvement in normal ovarian functions, gap junction proteins, particularly Cx43, seem to act as cancer suppressors. A summary of our present knowledge regarding gap junctional communication (GJC) and the ovarian gap junction proteins in normally developing ovaries and under pathological conditions is presented in this review.
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Affiliation(s)
- Eran Gershon
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
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Gitenay D, Lyan B, Talvas J, Mazur A, Georgé S, Caris-Veyrat C, Rock E. Serum from rats fed red or yellow tomatoes induces Connexin43 expression independently from lycopene in a prostate cancer cell line. Biochem Biophys Res Commun 2007; 364:578-82. [PMID: 17959141 DOI: 10.1016/j.bbrc.2007.10.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Accepted: 10/08/2007] [Indexed: 01/11/2023]
Abstract
Epidemiologic studies suggested a protective effect of tomatoes against prostate cancer brought by lycopene, a carotenoid conferring the red colour of tomatoes. However, intervention studies on patients have shown that the preventive effect of tomato was more potent than that of lycopene. The aim of this study was to compare the effects of red tomato, yellow tomato (devoid of lycopene) and lycopene on Connexin43 (Cx43) expression, a protein regulating cell growth, on a prostate cancer cell line expressing the androgen receptor. Cells were incubated with serum from rats fed a control diet (CS) or control diet supplemented with red tomato (RTS), yellow tomato (YTS) or lycopene beadlets (LBS). After exposure of the cells to RTS or YTS for 48h, the expression of Cx43 was significantly increased compared to cells exposed to CS. Whereas LBS effect was not significantly different. The cells incubated with RTS and LBS had similar levels of lycopene, while those incubated with YTS contained no lycopene. These data first show that serum nutritionally enriched with red and yellow tomatoes could up-regulate Cx43 turn-over in PC3AR cells independently from lycopene level. Within the physiological approach used in the present study, it can be concluded that compounds other than lycopene contribute to the preventive effect of tomatoes.
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Affiliation(s)
- Delphine Gitenay
- Unité de Nutrition Humaine, INRA, Centre de Clermont-Ferrand/Theix, 63122 Saint-Genès-Champanelle, France
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Hokaiwado N, Asamoto M, Futakuchi M, Ogawa K, Takahashi S, Shirai T. Both early and late stages of hepatocarcinogenesis are enhanced in Cx32 dominant negative mutant transgenic rats with disrupted gap junctional intercellular communication. J Membr Biol 2007; 218:101-6. [PMID: 17978847 DOI: 10.1007/s00232-007-9053-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Accepted: 06/04/2007] [Indexed: 10/22/2022]
Abstract
Connexins are a family of transmembrane proteins essential for the gap junctions, which mediate cell-to-cell communication. Several connexins are reported to be tumor suppressors, and we have established transgenic (Tg) rats with a connexin 32 (Cx32) dominant negative mutant showing high sensitivity to early-stage diethylnitrosamine (DEN)-induced liver carcinogenesis. In this study, we carried out two independent experiments using Tg rats to further investigate the roles of disrupted Cx32 in late-stage carcinogenesis (carcinoma induction and metastasis) in the liver. In the first experiment, of 50 weeks' duration, DEN was administered at 6 weeks of age and at 26 weeks to explore the effects of carcinogen treatments at different stages. The number of hepatocellular carcinomas (HCCs) was significantly increased in Tg compared with non-Tg rats. The second experiment focused on the effects of Cx32 disruption on metastasis by HCCs induced by administration of DEN and N-nitrosomorpholine. Only Tg rats had multiple metastases of HCCs in the lung, and the development and growth of HCCs was dramatically accelerated in Tg compared to non-Tg rats. Thus, normal function of Cx32 may be essential for suppression of both early and late stages of hepatocarcinogenesis.
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Affiliation(s)
- Naomi Hokaiwado
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi, Japan
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Conklin C, Huntsman D, Yorida E, Makretsov N, Turbin D, Bechberger JF, Sin WC, Naus CC. Tissue microarray analysis of connexin expression and its prognostic significance in human breast cancer. Cancer Lett 2007; 255:284-94. [PMID: 17583422 DOI: 10.1016/j.canlet.2007.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 04/30/2007] [Accepted: 05/02/2007] [Indexed: 10/23/2022]
Abstract
Breast cancer accounts for approximately 15% of all cancer deaths. Currently, axillary nodal status is the most reliable prognostic indicator for breast cancer. Tumor size and histological grade are used to stage breast cancer. Estrogen receptor/progesterone receptor (ER/PR) and HER-2/neu status are useful in predicting patient survival and relapse. Ki67, an indicator of proliferative activity, also correlates well with prognosis. Connexin proteins form gap junction channels, permitting intercellular exchange of ions and small molecules. Reduced connexin protein levels and impaired gap junctional intercellular communication are associated with tumor phenotypes. This study investigated the prognostic value of connexin proteins as breast cancer markers. Tissue microarrays, containing 438 cases of invasive breast carcinoma, were stained with Cx26, Cx32, and Cx43 antibodies. The degree of connexin immunoreactivity was determined and then correlated with patient outcome, tumor grade, tumor size, lymph node status, and immunohistochemical markers, such as p53, ER/PR status, Ki67 and c-erbB-2 expression. Cx26, Cx32, or Cx43 did not correlate well with tumor grade, tumor size, p53 or c-erbB-2 status. There was an inverse correlation between Cx32 and lymph node status (P <0.05) and a positive correlation between Cx43 and PR status (P <0.01). Cx32 and Cx43 correlated positively with ER status (P <0.01). Cx43 correlated negatively with Ki67 expression (P <0.01). Cx26, Cx32, and Cx43 did not correlate with patient outcome. Based on our observations in this study, connexin proteins do not appear to be reliable indicators of breast cancer prognosis.
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Affiliation(s)
- Chris Conklin
- Department of Cellular & Physiological Sciences, The University of British Columbia, BC, Canada V6T 1Z3
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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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Hamada N, Matsumoto H, Hara T, Kobayashi Y. Intercellular and intracellular signaling pathways mediating ionizing radiation-induced bystander effects. JOURNAL OF RADIATION RESEARCH 2007; 48:87-95. [PMID: 17327686 DOI: 10.1269/jrr.06084] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A rapidly growing body of experimental evidence indicates that ionizing radiation induces biological effects in non-irradiated bystander cells that have received signals from adjacent or distant irradiated cells. This phenomenon, which has been termed the ionizing radiation-induced bystander effect, challenges the long-standing paradigm that radiation traversal through the nucleus of a cell is a prerequisite to elicit genetic damage or a biological response. Bystander effects have been observed in a number of experimental systems, and cells whose nucleus or cytoplasm is irradiated exert bystander responses. Bystander cells manifest a multitude of biological consequences, such as genetic and epigenetic changes, alterations in gene expression, activation of signal transduction pathways, and delayed effects in their progeny. Several mediating mechanisms have been proposed. These involve gap junction-mediated intercellular communication, secreted soluble factors, oxidative metabolism, plasma membrane-bound lipid rafts, and calcium fluxes. This paper reviews briefly the current knowledge of the bystander effect with a focus on proposed mechanisms. The potential benefit of bystander effects to cancer radiotherapy will also be discussed.
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Affiliation(s)
- Nobuyuki Hamada
- Department of Quantum Biology, Division of Bioregulatory Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan.
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Jung JW, Cho SD, Ahn NS, Yang SR, Park JS, Jo EH, Hwang JW, Aruoma OI, Lee YS, Kang KS. Effects of the histone deacetylases inhibitors sodium butyrate and trichostatin A on the inhibition of gap junctional intercellular communication by H2O2- and 12-O-tetradecanoylphorbol-13-acetate in rat liver epithelial cells. Cancer Lett 2006; 241:301-8. [PMID: 16337085 DOI: 10.1016/j.canlet.2005.10.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Revised: 10/24/2005] [Accepted: 10/24/2005] [Indexed: 01/11/2023]
Abstract
The histone deacetylase (HDAC) inhibitors, trichostatin A (TSA) and sodium butyrate (NaBu) are considered as potent therapeutic agents for cancer treatment presenting therapeutic benefits with less risk of side effects. The microbial metabolite, TSA is a potent reversible and highly specific inhibitor of mammalian histone deacetylases. NaBu causes hyperacetylation of core histones with effects similar to TSA but it is not a specific inhibitor of HDACs. The gap junction is a channel in the plasma membrane of most cell types which allows direct communication (gap junctional intercellular communication; GJIC) of small molecules and ions. Modulation of GJIC is a known cellular event associated with tumor promotion. The effects of NaBu and TSA on the H(2)O(2)- and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced GJIC inhibition of WB cells and the mechanisms involved in the process were assessed. TSA and NaBu exerted differential preventive effects on the H(2)O(2) and TPA-induced inhibition of GJIC as well as hyperphosphorylation of connexin43 (Cx43) in WB-F344 rat liver epithelial cells (WB cells). NaBu prevented the TPA-induced GJIC inhibition via ERK1/2 inactivation whilst TSA restored the H(2)O(2)-induced GJIC inhibition and Cx43 hyperphosphorylation by preventing p38 MAP kinase. The inhibition of tyrosine phosphorylation and down-regulation of src protein observed may also contribute to Connexin 43 dephosphorylation and GJIC restoration by TSA and NaBu partly through depletion of src protein pool. Thus, TSA and NaBu exert differential effects on chemically induced GJIC inhibition via modulation of MAP kinases and partly, tyrosine kinases.
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Affiliation(s)
- Ji-Won Jung
- Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, San 56-1, Sillim-dong, Gwanakgu, Seoul 151-742, South Korea
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