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Aoyama Y, Naiki-Ito A, Xiaochen K, Komura M, Kato H, Nagayasu Y, Inaguma S, Tsuda H, Tomita M, Matsuo Y, Takiguchi S, Takahashi S. Lactoferrin Prevents Hepatic Injury and Fibrosis via the Inhibition of NF-κB Signaling in a Rat Non-Alcoholic Steatohepatitis Model. Nutrients 2021; 14:42. [PMID: 35010924 PMCID: PMC8746867 DOI: 10.3390/nu14010042] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 12/12/2022] Open
Abstract
Non-alcoholic steatohepatitis (NASH) can cause liver cirrhosis and hepatocellular carcinoma (HCC), with cases increasing worldwide. To reduce the incidence of liver cirrhosis and HCC, NASH is targeted for the development of treatments, along with viral hepatitis and alcoholic hepatitis. Lactoferrin (LF) has antioxidant, anti-cancer, and anti-inflammatory activities. However, whether LF affects NASH and fibrosis remains unelucidated. We aimed to clarify the chemopreventive effect of LF on NASH progression. We used a NASH model with metabolic syndrome established using connexin 32 (Cx32) dominant negative transgenic (Cx32ΔTg) rats. Cx32ΔTg rats (7 weeks old) were fed a high-fat diet and intraperitoneally injected with dimethylnitrosamine (DMN). Rats were divided into three groups for LF treatment at 0, 100, or 500 mg/kg/day for 17 weeks. Lactoferrin significantly protected steatosis and lobular inflammation in Cx32ΔTg rat livers and attenuated bridging fibrosis or liver cirrhosis induced by DMN. By quantitative RT-PCR, LF significantly down-regulated inflammatory (Tnf-α, Il-6, Il-18, and Il-1β) and fibrosis-related (Tgf-β1, Timp2, and Col1a1) cytokine mRNAs. Phosphorylated nuclear factor (NF)-κB protein decreased in response to LF, while phosphorylated JNK protein was unaffected. These results indicate that LF might act as a chemopreventive agent to prevent hepatic injury, inflammation, and fibrosis in NASH via NF-κB inactivation.
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Affiliation(s)
- Yoshinaga Aoyama
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (Y.A.); (K.X.); (M.K.); (H.K.); (Y.N.); (S.I.); (S.T.)
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (Y.M.); (S.T.)
| | - Aya Naiki-Ito
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (Y.A.); (K.X.); (M.K.); (H.K.); (Y.N.); (S.I.); (S.T.)
| | - Kuang Xiaochen
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (Y.A.); (K.X.); (M.K.); (H.K.); (Y.N.); (S.I.); (S.T.)
| | - Masayuki Komura
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (Y.A.); (K.X.); (M.K.); (H.K.); (Y.N.); (S.I.); (S.T.)
| | - Hiroyuki Kato
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (Y.A.); (K.X.); (M.K.); (H.K.); (Y.N.); (S.I.); (S.T.)
| | - Yuko Nagayasu
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (Y.A.); (K.X.); (M.K.); (H.K.); (Y.N.); (S.I.); (S.T.)
| | - Shingo Inaguma
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (Y.A.); (K.X.); (M.K.); (H.K.); (Y.N.); (S.I.); (S.T.)
| | - Hiroyuki Tsuda
- Nanotoxicology Project, Nagoya City University, Nagoya 467-8603, Japan;
| | | | - Yoichi Matsuo
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (Y.M.); (S.T.)
| | - Shuji Takiguchi
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (Y.M.); (S.T.)
| | - Satoru Takahashi
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (Y.A.); (K.X.); (M.K.); (H.K.); (Y.N.); (S.I.); (S.T.)
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Leroy K, Silva Costa CJ, Pieters A, dos Santos Rodrigues B, Van Campenhout R, Cooreman A, Tabernilla A, Cogliati B, Vinken M. Expression and Functionality of Connexin-Based Channels in Human Liver Cancer Cell Lines. Int J Mol Sci 2021; 22:12187. [PMID: 34830068 PMCID: PMC8623148 DOI: 10.3390/ijms222212187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/08/2021] [Accepted: 11/08/2021] [Indexed: 01/14/2023] Open
Abstract
Liver cancer cell lines are frequently used in vitro tools to test candidate anti-cancer agents as well as to elucidate mechanisms of liver carcinogenesis. Among such mechanisms is cellular communication mediated by connexin-based gap junctions. The present study investigated changes in connexin expression and gap junction functionality in liver cancer in vitro. For this purpose, seven human liver cancer cell lines, as well as primary human hepatocytes, were subjected to connexin and gap junction analysis at the transcriptional, translational and activity level. Real-time quantitative reverse transcription polymerase chain reaction analysis showed enhanced expression of connexin43 in the majority of liver cancer cell lines at the expense of connexin32 and connexin26. Some of these changes were paralleled at the protein level, as evidenced by immunoblot analysis and in situ immunocytochemistry. Gap junctional intercellular communication, assessed by the scrape loading/dye transfer assay, was generally low in all liver cancer cell lines. Collectively, these results provide a full scenario of modifications in hepatocyte connexin production and gap junction activity in cultured liver cancer cell lines. The findings may be valuable for the selection of neoplastic hepatocytes for future mechanistic investigation and testing of anti-cancer drugs that target connexins and their channels.
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Affiliation(s)
- Kaat Leroy
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (B.d.S.R.); (R.V.C.); (A.C.); (A.T.)
| | - Cícero Júlio Silva Costa
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Av. Prof. Dr. Orlando Marques de Paiva 87, Cidade Universitária, São Paulo 05508-270, Brazil; (C.J.S.C.); (B.C.)
| | - Alanah Pieters
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (B.d.S.R.); (R.V.C.); (A.C.); (A.T.)
| | - Bruna dos Santos Rodrigues
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (B.d.S.R.); (R.V.C.); (A.C.); (A.T.)
| | - Raf Van Campenhout
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (B.d.S.R.); (R.V.C.); (A.C.); (A.T.)
| | - Axelle Cooreman
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (B.d.S.R.); (R.V.C.); (A.C.); (A.T.)
| | - Andrés Tabernilla
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (B.d.S.R.); (R.V.C.); (A.C.); (A.T.)
| | - Bruno Cogliati
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Av. Prof. Dr. Orlando Marques de Paiva 87, Cidade Universitária, São Paulo 05508-270, Brazil; (C.J.S.C.); (B.C.)
| | - Mathieu Vinken
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (K.L.); (A.P.); (B.d.S.R.); (R.V.C.); (A.C.); (A.T.)
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Naiki-Ito A, Kato H, Naiki T, Yeewa R, Aoyama Y, Nagayasu Y, Suzuki S, Inaguma S, Takahashi S. A novel model of non-alcoholic steatohepatitis with fibrosis and carcinogenesis in connexin 32 dominant-negative transgenic rats. Arch Toxicol 2020; 94:4085-4097. [PMID: 32833043 PMCID: PMC7655588 DOI: 10.1007/s00204-020-02873-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/12/2020] [Indexed: 02/07/2023]
Abstract
Non-alcoholic steatohepatitis (NASH) is a recognized risk factor for liver fibrosis and malignancies, and is associated with features of metabolic syndrome, such as obesity and insulin resistance (IR). We previously demonstrated that the disturbance of connexin 32 (Cx32), a gap junctional protein of hepatocytes, exacerbated NASH in Cx32 dominant-negative transgenic (Cx32ΔTg) rats fed methionine choline-deficient diet (MCDD). MCDD is well-established means of inducing NASH in rodents; however, the Cx32ΔTg-MCDD NASH model does not reproduce obesity and IR. In this study, we aimed to establish an improved NASH model. Eight-week-old male Cx32ΔTg and wild-type (Wt) rats received a high-fat diet (HFD) with dimethylnitrosamine (DMN) for 12 weeks. The HFD with DMN led to gains in body, liver, and visceral fat weights in both genotypes. IR was significantly greater in Cx32ΔTg than in Wt rats. Elevation of serum hepatic enzymes (AST, ALT), inflammatory cytokine expressions (Tnfα, Il-6, Tgf-β1, Il-1β, Timp2, and Col1a1), steatohepatitis, and fibrosis were significantly greater in Cx32ΔTg as compared with Wt rats. Regarding carcinogenesis, the number and area of glutathione S-transferase placental form (GST-P)-positive preneoplastic hepatic foci were significantly increased in Cx32ΔTg versus Wt rats. Moreover, activation of NF-κB and JNK contributed to the progression of NASH in Cx32ΔTg rats. These results suggest that Cx32 dysfunction promoted the progression of NASH, metabolic syndrome, and carcinogenesis. Therefore, the novel Cx32ΔTg-HFD-DMN NASH model may be a rapid and useful tool for evaluating the progression of NASH.
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MESH Headings
- Animals
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Connexins/genetics
- Connexins/metabolism
- Cytokines/metabolism
- Diet, High-Fat
- Dimethylnitrosamine
- Disease Progression
- Inflammation Mediators/metabolism
- Insulin Resistance
- JNK Mitogen-Activated Protein Kinases/metabolism
- Liver/metabolism
- Liver/pathology
- Liver Cirrhosis, Experimental/etiology
- Liver Cirrhosis, Experimental/genetics
- Liver Cirrhosis, Experimental/metabolism
- Liver Cirrhosis, Experimental/pathology
- Liver Neoplasms, Experimental/etiology
- Liver Neoplasms, Experimental/genetics
- Liver Neoplasms, Experimental/metabolism
- Liver Neoplasms, Experimental/pathology
- Male
- NF-kappa B/metabolism
- Non-alcoholic Fatty Liver Disease/etiology
- Non-alcoholic Fatty Liver Disease/genetics
- Non-alcoholic Fatty Liver Disease/metabolism
- Non-alcoholic Fatty Liver Disease/pathology
- Rats, Transgenic
- Signal Transduction
- Gap Junction beta-1 Protein
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Affiliation(s)
- Aya Naiki-Ito
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan.
| | - Hiroyuki Kato
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Taku Naiki
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Ranchana Yeewa
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Yoshinaga Aoyama
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Yuko Nagayasu
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Shugo Suzuki
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
- Department of Molecular Pathology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Shingo Inaguma
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Satoru Takahashi
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
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4
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Leroy K, Pieters A, Tabernilla A, Cooreman A, Van Campenhout R, Cogliati B, Vinken M. Targeting gap junctional intercellular communication by hepatocarcinogenic compounds. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2020; 23:255-275. [PMID: 32568623 DOI: 10.1080/10937404.2020.1781010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Gap junctions in liver, as in other organs, play a critical role in tissue homeostasis. Inherently, these cellular constituents are major targets for systemic toxicity and diseases, including cancer. This review provides an overview of chemicals that compromise liver gap junctions, in particular biological toxins, organic solvents, pesticides, pharmaceuticals, peroxides, metals and phthalates. The focus in this review is placed upon the mechanistic scenarios that underlie these adverse effects. Further, the potential use of gap junctional activity as an in vitro biomarker to identify non-genotoxic hepatocarcinogenic chemicals is discussed.
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Affiliation(s)
- Kaat Leroy
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Alanah Pieters
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Andrés Tabernilla
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Axelle Cooreman
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Raf Van Campenhout
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Bruno Cogliati
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Cidade Universitária , São Paulo, Brazil
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
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Xiang Y, Wang Q, Guo Y, Ge H, Fu Y, Wang X, Tao L. Cx32 exerts anti-apoptotic and pro-tumor effects via the epidermal growth factor receptor pathway in hepatocellular carcinoma. J Exp Clin Cancer Res 2019; 38:145. [PMID: 30947731 PMCID: PMC6449973 DOI: 10.1186/s13046-019-1142-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/18/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Abnormal expression or distribution of connexin 32 (Cx32) is associated with hepatocarcinogenesis, but the role of Cx32 and the underlying mechanisms are still unclear. METHODS The expression level of Cx32 in 96 hepatocellular carcinoma (HCC) specimens was determined using western blotting and immunohistochemistry. The correlation between Cx32 expression and clinicopathological parameters was analyzed. The cell apoptosis rate was examined using flow cytometry and western blotting. The role of Cx32 in the Src kinase and epidermal growth factor receptor (EGFR) signaling pathways was measured by quantitative real-time PCR, western blotting and coimmunoprecipitation (CO-IP). The effect of Cx32 overexpression on the streptonigrin (SN)-induced tumor growth suppression and apoptosis was assessed in nude mice. RESULTS Our study showed that overexpressed Cx32 accumulated in the cytoplasm and that Cx32-containing gap junctions (GJs) were nearly absent in HCC specimens. Upregulated Cx32 expression was highly correlated with advanced tumor-node-metastasis (TNM) stage and poor tumor differentiation and was an independent predictive marker for poor prognosis in HCC. Overexpression of Cx32 significantly inhibited SN-induced apoptosis by activating the EGFR signaling pathway in vitro and in vivo. Moreover, the expression levels of Cx32 and EGFR were positively correlated in HCC specimens. The CO-IP experiments demonstrated that Cx32 could bind to Src kinase, and the western blotting results revealed that Cx32 increased the levels of EGFR and p-EGFR by upregulating Src expression. CONCLUSION The present study demonstrated that overexpressed and internalized Cx32 was associated with advanced TNM stage and poor tumor differentiation and predicted poor prognosis in HCC. Cx32 facilitated HCC progression by blocking chemotherapy-induced apoptosis in vitro and in vivo via interacting with Src and thus promoting the phosphorylation of EGFR, subsequently activating the EGFR signaling pathway. Cx32 may be a potential biomarker and a new therapeutic target for HCC.
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Affiliation(s)
- Yuke Xiang
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080 People’s Republic of China
| | - Qin Wang
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080 People’s Republic of China
| | - Yunquan Guo
- Tumor Research Institute, Xinjiang Medical University Affiliated Tumor Hospital and State Key Laboratory, Urumqi, 830000 People’s Republic of China
| | - Hui Ge
- Tumor Research Institute, Xinjiang Medical University Affiliated Tumor Hospital and State Key Laboratory, Urumqi, 830000 People’s Republic of China
| | - Yile Fu
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080 People’s Republic of China
| | - Xiyan Wang
- Tumor Research Institute, Xinjiang Medical University Affiliated Tumor Hospital and State Key Laboratory, Urumqi, 830000 People’s Republic of China
| | - Liang Tao
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080 People’s Republic of China
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Wong P, Laxton V, Srivastava S, Chan YWF, Tse G. The role of gap junctions in inflammatory and neoplastic disorders (Review). Int J Mol Med 2017; 39:498-506. [PMID: 28098880 PMCID: PMC5360388 DOI: 10.3892/ijmm.2017.2859] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 12/23/2016] [Indexed: 12/29/2022] Open
Abstract
Gap junctions are intercellular channels made of connexin proteins, mediating both electrical and biochemical signals between cells. The ability of gap junction proteins to regulate immune responses, cell proliferation, migration, apoptosis and carcinogenesis makes them attractive therapeutic targets for treating inflammatory and neoplastic disorders in different organ systems. Alterations in gap junction profile and expression levels are observed in hyperproliferative skin disorders, lymphatic vessel diseases, inflammatory lung diseases, liver injury and neoplastic disorders. It is now recognized that the therapeutic effects mediated by traditional pharmacological agents are dependent upon gap junction communication and may even act by influencing gap junction expression or function. Novel strategies for modulating the function or expression of connexins, such as the use of synthetic mimetic peptides and siRNA technology are considered.
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Affiliation(s)
- Pui Wong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, SAR, P.R. China
| | - Victoria Laxton
- Intensive Care Department, Royal Brompton and Harefield NHS Foundation Trust, London SW3 6NP
| | | | - Yin Wah Fiona Chan
- School of Biological Sciences, University of Cambridge, Cambridge CB2 1AG, UK
| | - Gary Tse
- Department of Medicine and Therapeutics
- Li Ka Shing Institute of Health Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, SAR, P.R. China
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Abstract
Being critical mediators of liver homeostasis, connexins and their channels are frequently involved in liver toxicity. In the current paper, specific attention is paid to actions of hepatotoxic drugs on these communicative structures. In a first part, an overview is provided on the structural, regulatory and functional properties of connexin-based channels in the liver. In the second part, documented effects of acetaminophen, hypolipidemic drugs, phenobarbital and methapyriline on connexin signaling are discussed. Furthermore, the relevance of this subject for the fields of clinical and in vitro toxicology is demonstrated. Relevance for patients: The role of connexin signaling in drug-induced hepatotoxicity may be of high clinical relevance, as it offers perspectives for the therapeutic treatment of such insults by interfering with connexin channel opening.
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Affiliation(s)
- Michaël Maes
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
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8
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Nohmi T, Masumura K, Toyoda-Hokaiwado N. Transgenic rat models for mutagenesis and carcinogenesis. Genes Environ 2017; 39:11. [PMID: 28174618 PMCID: PMC5289047 DOI: 10.1186/s41021-016-0072-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 12/08/2016] [Indexed: 01/18/2023] Open
Abstract
Rats are a standard experimental animal for cancer bioassay and toxicological research for chemicals. Although the genetic analyses were behind mice, rats have been more frequently used for toxicological research than mice. This is partly because they live longer than mice and induce a wider variety of tumors, which are morphologically similar to those in humans. The body mass is larger than mice, which enables to take samples from organs for studies on pharmacokinetics or toxicokinetics. In addition, there are a number of chemicals that exhibit marked species differences in the carcinogenicity. These compounds are carcinogenic in rats but not in mice. Such examples are aflatoxin B1 and tamoxifen, both are carcinogenic to humans. Therefore, negative mutagenic/carcinogenic responses in mice do not guarantee that the chemical is not mutagenic/carcinogenic to rats or perhaps to humans. To facilitate research on in vivo mutagenesis and carcinogenesis, several transgenic rat models have been established. In general, the transgenic rats for mutagenesis are treated with chemicals longer than transgenic mice for more exact examination of the relationship between mutagenesis and carcinogenesis. Transgenic rat models for carcinogenesis are engineered mostly to understand mechanisms underlying chemical carcinogenesis. Here, we review papers dealing with the transgenic rat models for mutagenesis and carcinogenesis, and discuss the future perspective.
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Affiliation(s)
- Takehiko Nohmi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501 Japan
- Present address: Biological Safety Research Center, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501 Japan
| | - Kenichi Masumura
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501 Japan
| | - Naomi Toyoda-Hokaiwado
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501 Japan
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9
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Kato H, Naiki-Ito A, Naiki T, Suzuki S, Yamashita Y, Sato S, Sagawa H, Kato A, Kuno T, Takahashi S. Connexin 32 dysfunction promotes ethanol-related hepatocarcinogenesis via activation of Dusp1-Erk axis. Oncotarget 2016; 7:2009-21. [PMID: 26655499 PMCID: PMC4811513 DOI: 10.18632/oncotarget.6511] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 11/21/2015] [Indexed: 01/25/2023] Open
Abstract
There is abundant epidemiological evidence that heavy alcohol intake contributes to hepatocellular carcinoma (HCC) development. Previous reports indicated that connexin 32 (Cx32), which is a major hepatocyte gap junction protein, is down-regulated in chronic liver disease and has a protective role in hepatocarcinogenesis. However, functions of Cx32 in alcohol-related hepatocarcinogenesis have not been clarified. To evaluate them, 9-week-old Cx32 dominant negative transgenic (Tg) rats and their wild-type (Wt) littermates were given 1 % or 5 % ethanol (EtOH) or water ad libitum, for 16 weeks after an intraperitoneal injection of diethylnitrosamine (200 mg/kg). EtOH significantly increased the incidence and multiplicity of HCC and total tumors in a dose-dependent manner in Tg rats, but not in Wt rats. Although the number and area of glutathione S-transferase placental form (GST-P) positive foci were not significantly different between the groups, EtOH increased the Ki-67 labeling indices in GST-P positive foci only in Tg rats. EtOH up-regulated phosphorylated Erk1/2 with decrease of the Erk1/2 inhibitor, dual specificity protein phosphatase 1 (Dusp1) in whole livers of Tg and Wt rats. Immunofluorescence staining and quantitative RT-PCR revealed that EtOH significantly increased nucleolar localization of phosphorylated Erk1/2 and contrastingly reduced Dusp1 protein and mRNA expression in GST-P positive foci and HCC of Tg rats as compared to those of Wt rats. These findings suggest that Cx32 dysfunction like in chronic liver disease promoted EtOH-associated hepatocarcinogenesis through dysregulation of Erk-Dusp1 signaling.
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Affiliation(s)
- Hiroyuki Kato
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Aya Naiki-Ito
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Taku Naiki
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Shugo Suzuki
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yoriko Yamashita
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Shinya Sato
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hiroyuki Sagawa
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Akihisa Kato
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Toshiya Kuno
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Satoru Takahashi
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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IGARASHI I, MAKINO T, KAI K, TERANISHI M, TAKASAKI W, SATOH H, FURUHAMA K. Localization of connexin 32 in spontaneous liver lesions of mice. J Vet Med Sci 2016; 78:113-6. [PMID: 26268664 PMCID: PMC4751127 DOI: 10.1292/jvms.14-0437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 07/28/2015] [Indexed: 11/24/2022] Open
Abstract
We examined the localization of connexin 32 (Cx32), a component of gap junctions, in 24-month-old male B6C3F1 mice with spontaneously occurring hepatocellular altered foci or tumors. Immunohistochemically, Cx32-staining intensity in cell-to-cell membranes of altered hepatocytes was decreased in eosinophilic foci and increased in basophilic foci as compared to those in intact hepatocytes. These alterations were enhanced in adenomas and carcinomas with both eosinophilic and basophilic cytoplasm. In cell membranes facing on the sinusoidal portions, the intensities increased in all lesions. Image analyses confirmed that the spot areas of Cx32 were decreased in eosinophilic foci, but increased in basophilic foci, adenomas and carcinomas. These results demonstrate that Cx32 shows different expression in different types of hepatic lesions.
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Affiliation(s)
- Isao IGARASHI
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co.,
Ltd., Kitakasai, Edogawa, Tokyo 134–8630, Japan
| | - Toshihiko MAKINO
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co.,
Ltd., Kitakasai, Edogawa, Tokyo 134–8630, Japan
| | - Kiyonori KAI
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co.,
Ltd., Kitakasai, Edogawa, Tokyo 134–8630, Japan
| | - Munehiro TERANISHI
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co.,
Ltd., Kitakasai, Edogawa, Tokyo 134–8630, Japan
| | - Wataru TAKASAKI
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co.,
Ltd., Kitakasai, Edogawa, Tokyo 134–8630, Japan
| | - Hiroshi SATOH
- Cooperative Department of Veterinary Medicine, Iwate
University, Morioka, Iwate 020–8550, Japan
| | - Kazuhisa FURUHAMA
- Cooperative Department of Veterinary Medicine, Iwate
University, Morioka, Iwate 020–8550, Japan
- United Graduate School of Veterinary Science, Gifu
University, Gifu 501–1193, Japan
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11
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Sagawa H, Naiki-Ito A, Kato H, Naiki T, Yamashita Y, Suzuki S, Sato S, Shiomi K, Kato A, Kuno T, Matsuo Y, Kimura M, Takeyama H, Takahashi S. Connexin 32 and luteolin play protective roles in non-alcoholic steatohepatitis development and its related hepatocarcinogenesis in rats. Carcinogenesis 2015; 36:1539-49. [PMID: 26494227 DOI: 10.1093/carcin/bgv143] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 09/20/2015] [Indexed: 02/06/2023] Open
Abstract
Non-alcoholic steatohepatitis (NASH) has the potential to lead to the development of cirrhosis and hepatocellular carcinoma (HCC). Connexin (Cx) 32, a hepatocyte gap-junction protein, plays a preventive role in hepatocarcinogenesis. However, the precise contribution of Cx32 in the development of NASH has not been established. In this study, we aimed to clarify the role of Cx32 and the chemopreventive effect of luteolin, an antioxidant flavonoid, on the progression of NASH and NASH-related hepatocarcinogenesis. Cx32 dominant negative transgenic (Cx32ΔTg) and wild-type (Wt) rats at 10 weeks of age were given diethylnitrosamine and fed methionine-choline-deficient diet (MCDD) or MCDD with luteolin for 12 weeks. MCDD induced steatohepatitis and fibrosis along with increased inflammatory cytokine expression and reactive oxygen species in the liver. These effects were more severe in Cx32ΔTg rats as compared with Wt rats, and significantly suppressed by luteolin in both genotypes. Concerning NASH-related hepatocarcinogenesis, the number of glutathione S-transferase placental form (GST-P)-positive foci was greater in Cx32ΔTg versus Wt rats, and significantly reduced by luteolin in Cx32ΔTg rats. Microarray analysis identified brain expressed, X-linked 1 (Bex1) as an upregulated gene in Cx32ΔTg rat liver. Quantitative RT-PCR and in situ hybridization revealed that increased Bex1 mRNA was localized in GST-P-positive foci in Cx32ΔTg rats, and the expression level was significantly decreased by luteolin. Moreover, Bex1 knockdown resulted in significant growth inhibition of the rat HCC cell lines. These results show that Cx32 and luteolin have suppressive roles in inflammation, fibrosis and hepatocarcinogenesis during NASH progression, suggesting a potential therapeutic application for NASH.
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Affiliation(s)
- Hiroyuki Sagawa
- Department of Experimental Pathology and Tumor Biology, Department of Gastroenterological Surgery and
| | - Aya Naiki-Ito
- Department of Experimental Pathology and Tumor Biology,
| | - Hiroyuki Kato
- Department of Experimental Pathology and Tumor Biology
| | - Taku Naiki
- Department of Experimental Pathology and Tumor Biology
| | | | - Shugo Suzuki
- Department of Experimental Pathology and Tumor Biology
| | - Shinya Sato
- Department of Experimental Pathology and Tumor Biology
| | - Kosuke Shiomi
- Department of Experimental Pathology and Tumor Biology
| | - Akihisa Kato
- Department of Experimental Pathology and Tumor Biology, Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, 1-Kawasumi, Mizuho-cho, Mizuho-ku 467-8601, Nagoya, Japan
| | - Toshiya Kuno
- Department of Experimental Pathology and Tumor Biology
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12
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Abdulrahman Almatrrouk S, Oliver AW, Hampson L, Hampson IN. Targeting gap junction intercellular communication as a potential therapy for HCV-related carcinogenesis. Future Virol 2014. [DOI: 10.2217/fvl.14.50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ABSTRACT: Worldwide, at least 170 million people are infected with hepatitis C virus (HCV), which is associated with hepatocellular carcinoma (HCC). With the recent success of Sofosbuvir (and other agents) antiviral therapy may be used as a future early-stage HCC treatment; however, in the short term, a cost-effective solution is needed to treat patients with viral-associated HCC. Here, we emphasize the potential of targeting gap junction intercellular communication (GJIC) as a therapeutic approach for HCC as HCV perturbs GJIC, which is linked to cellular transformation. We review the ROCK inhibitor Y-27632 and structurally related compounds that may inhibit the carcinogenic properties of HCV.
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Affiliation(s)
| | - Anthony W Oliver
- University of Manchester, Viral Oncology, Research Floor, St Mary's Hospital, Manchester, UK
| | - Lynne Hampson
- University of Manchester, Viral Oncology, Research Floor, St Mary's Hospital, Manchester, UK
| | - Ian N Hampson
- University of Manchester, Viral Oncology, Research Floor, St Mary's Hospital, Manchester, UK
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13
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Igarashi I, Makino T, Suzuki Y, Kai K, Teranishi M, Takasaki W, Furuhama K. Background lesions during a 24-month observation period in connexin 32-deficient mice. J Vet Med Sci 2013; 75:207-10. [PMID: 23001129 DOI: 10.1292/jvms.12-0280] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Connexin 32 (Cx32) is a major gap junction protein in the liver. Neoplastic and non-neoplastic lesions were examined in Cx32-deficient (Cx32KO) mice maintained for 24-month, and compared with those in wild-type mice as a corresponding control. In neoplastic lesions, hepatocellular carcinoma increased significantly only in male Cx32KO mice, suggesting that Cx32 deficiency may be related to their pathogenesis. For females, the incidence of pituitary adenoma in the pars distalis of Cx32KO mice was lower than that of wild-type mice. No non-neoplastic lesions related to Cx32-deficiency were observed in the Cx32KO mice. In conclusion, these results demonstrate that the incidence of hepatocellular carcinoma increases only in male Cx32KO mice, presumably due to enhanced tumor promotion and progression signals associated with Cx32 deficiency.
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Affiliation(s)
- Isao Igarashi
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., Fukuroi, Shizuoka, Japan.
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14
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Naiki-Ito A, Kato H, Asamoto M, Naiki T, Shirai T. Age-dependent carcinogenic susceptibility in rat liver is related to potential of gap junctional intercellular communication. Toxicol Pathol 2012; 40:715-21. [PMID: 22569583 DOI: 10.1177/0192623312441402] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Connexin 32 (Cx32) is a major gap junction protein in the liver. The authors previously demonstrated that transgenic rats carrying a dominant negative mutant of Cx32 (Cx32ΔTg) have much decreased capacity for gap junctional intercellular communication (GJIC) and increased susceptibility to diethylnitrosamine (DEN)-induced hepatocarcinogenesis as compared to littermate wild-type (wt) rats. To evaluate the age-dependent susceptibility to DEN-induced hepatocarcinogenesis and alteration of GJIC function, male Cx32ΔTg and wt rats at 10, 30, or 85 weeks old were given a single intraperitoneal administration of DEN (40 mg/rat) and sacrificed 12 weeks later. The number and area of glutathione S-transferase placental form (GST-P)-positive preneoplastic foci were significantly increased in the liver of 10- and 30-wk-old Cx32ΔTg rats compared with age-matched wt. However, in the 85-wk-old rats, both Cx32ΔTg and wt rats had similarly large number and area of GST-P-positive foci, and the difference was not significant. Interestingly, function of hepatic GJIC was reduced and protein and mRNA expression of Cx32 were decreased with aging in wt rats. These results suggest that a decline of hepatic intercellular communication through gap junction results in increased susceptibility to DEN-induced hepatocarcinogenesis in aged rats.
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Affiliation(s)
- Aya Naiki-Ito
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan.
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Ogawa K, Pitchakarn P, Suzuki S, Chewonarin T, Tang M, Takahashi S, Naiki-Ito A, Sato S, Takahashi S, Asamoto M, Shirai T. Silencing of connexin 43 suppresses invasion, migration and lung metastasis of rat hepatocellular carcinoma cells. Cancer Sci 2012; 103:860-7. [PMID: 22320152 DOI: 10.1111/j.1349-7006.2012.02228.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 01/12/2012] [Accepted: 02/09/2012] [Indexed: 11/28/2022] Open
Abstract
To reduce cancer mortality, understanding of mechanisms of cancer metastasis is crucial. We have established six rat hepatocellular carcinoma (HCC) cell lines, which exhibit differing metastatic potential to the lung after inoculation into the tail veins of nude mice. In the present experiment, we investigated the process of cell attachment to metastatic sites and possible regulating factors. One hour after inoculation, two of two HCC cell lines with high metastatic potential and one of two HCC cell lines with low metastatic potential exhibited many attached cells in the lung. One day after inoculation, lung metastatic foci were observed only with highly-metastatic cells with elevated connexin 43 (Cx43) expression as assessed by cDNA array analysis. Furthermore, 24 or 48 h after transfection of an siRNA targeting Cx43, in vitro invasion and migration were suppressed by 68% (P < 0.001) and 36% (P < 0.05) compared with control-siRNA transfected cells, despite no differences in cellular morphology, cell proliferation or apoptotic activity. Moreover, the number of metastatic nodules per lung area in nude mice was significantly (P < 0.01) reduced. In conclusion, suppression of Cx43 expression in tumor cells reduced in vitro migration and invasion capacity and in vivo metastatic ability so that Cx43 has potential as a molecular target for prevention of cancer metastasis with Cx43 overexpressing tumors.
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Affiliation(s)
- Kumiko Ogawa
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
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16
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Disruption of Smad-dependent signaling for growth of GST-P-positive lesions from the early stage in a rat two-stage hepatocarcinogenesis model. Toxicol Appl Pharmacol 2010; 246:128-40. [DOI: 10.1016/j.taap.2010.04.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Revised: 03/22/2010] [Accepted: 04/08/2010] [Indexed: 11/30/2022]
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17
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Naiki-Ito A, Asamoto M, Naiki T, Ogawa K, Takahashi S, Sato S, Shirai T. Gap junction dysfunction reduces acetaminophen hepatotoxicity with impact on apoptotic signaling and connexin 43 protein induction in rat. Toxicol Pathol 2010; 38:280-6. [PMID: 20097795 DOI: 10.1177/0192623309357951] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Acetaminophen (APAP) is a widely used antipyretic and analgesic agent. However, overdosing and sometimes even a recommended dose can lead to serious and conceivably fatal liver toxicity. Therefore, it is important to clarify understand mechanisms of hepatotoxicity induced by APAP. Gap junctions, formed by connexin, have important roles in maintenance of tissue homeostasis and control of cell growth and differentiation. In the liver, Cx32 is a major gap junction protein whose expression is known to gradually decrease with chronic liver disease progression. In the present study, acute hepatotoxic effects of APAP were found to be reduced in Cx32 dominant negative transgenic rats lacking normal gap junctional intercellular communication in the liver. In littermate wild-type rats, the injured centrilobular hepatocytes were positive for TUNEL staining and featured elevated expre ssion of cleaved caspase-3 and Cx43, which is not expressed in normal hepatocytes. These results suggest that APAP hepatotoxicity involves apoptosis, and induction of Cx43 expression may play an important role in the apoptotic signaling. Moreover, gap junctional functions of Cx32 can play important roles in removing damaged hepatocytes by apoptosis for liver tissue homeostasis.
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Affiliation(s)
- Aya Naiki-Ito
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan. ayaito@-med.nagoya-cu.ac.jp
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Vinken M, Doktorova T, Decrock E, Leybaert L, Vanhaecke T, Rogiers V. Gap junctional intercellular communication as a target for liver toxicity and carcinogenicity. Crit Rev Biochem Mol Biol 2009; 44:201-22. [PMID: 19635038 DOI: 10.1080/10409230903061215] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Direct communication between hepatocytes, mediated by gap junctions, constitutes a major regulatory platform in the control of liver homeostasis, ranging from hepatocellular proliferation to hepatocyte cell death. Inherent to this pivotal task, gap junction functionality is frequently disrupted upon impairment of the homeostatic balance, as occurs during liver toxicity and carcinogenicity. In the present paper, the deleterious effects of a number of chemical and biological toxic compounds on hepatic gap junctions are discussed, including environmental pollutants, biological toxins, organic solvents, pesticides, pharmaceuticals, peroxides, metals and phthalates. Particular attention is paid to the molecular mechanisms that underlie the abrogation of gap junction functionality. Since hepatic gap junctions are specifically targeted by tumor promoters and epigenetic carcinogens, both in vivo and in vitro, inhibition of gap junction functionality is considered as a suitable indicator for the detection of nongenotoxic hepatocarcinogenicity.
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Affiliation(s)
- Mathieu Vinken
- Department of Toxicology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium.
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