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Connexins and cAMP Cross-Talk in Cancer Progression and Metastasis. Cancers (Basel) 2020; 13:cancers13010058. [PMID: 33379194 PMCID: PMC7795795 DOI: 10.3390/cancers13010058] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/21/2020] [Accepted: 12/21/2020] [Indexed: 02/06/2023] Open
Abstract
Simple Summary Different connexins play diverse roles in cancers, either tumor-suppressing or tumor-promoting. In lung cancer, Cx43 serves as a tumor suppressor at the early stage, but it can also be a tumor-promotor at an advanced stage and during metastasis. Moreover, other connexins, including Cx26, Cx31.1, and Cx32, can be tumor suppressors. In contrast, Cx30.3 can be a tumor-promotor. The roles of different connexins in different cancers have also been established. Cx43 acts as a tumor suppressor in colorectal cancer, breast cancer, and glioma, whereas Cx32 can be a suppressor in liver tumors and hepatocarcinogenesis. Cx26 can be a tumor suppressor in mammary tumors; in contrast, it can be a tumor-promotor in melanoma. Existing drugs/molecules targeting the cAMP/PKA/connexin axis act to regulate channel opening/closing. Mimic peptides, such as Gap19, Gap26, and Gap 27 block hemichannels, mimetic peptides, and CT9/CT10 and promote hemichannel opening and also hemichannel closing. Abstract Connexin-containing gap junctions mediate the direct exchange of small molecules between cells, thus promoting cell–cell communication. Connexins (Cxs) have been widely studied as key tumor-suppressors. However, certain Cx subtypes, such as Cx43 and Cx26, are overexpressed in metastatic tumor lesions. Cyclic adenosine monophosphate (cAMP) signaling regulates Cx expression and function via transcriptional control and phosphorylation. cAMP also passes through gap junction channels between adjacent cells, regulating cell cycle progression, particularly in cancer cell populations. Low levels of cAMP are sufficient to activate key effectors. The present review evaluates the mechanisms underlying Cx regulation by cAMP signaling and the role of gap junctions in cancer progression and metastasis. A deeper understanding of these processes might facilitate the development of novel anticancer drugs.
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Ocak S, Özkan MA, Ozkan F, Öz B, Celkan TT, Apak H. Çocukluk çağı medulloblastom olgularında P53, ERBB2, c-Kit ve BCL2 Ekspresyonunun prognostik ve klinik önemi. CUKUROVA MEDICAL JOURNAL 2019. [DOI: 10.17826/cumj.442463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Grek CL, Sheng Z, Naus CC, Sin WC, Gourdie RG, Ghatnekar GG. Novel approach to temozolomide resistance in malignant glioma: connexin43-directed therapeutics. Curr Opin Pharmacol 2018; 41:79-88. [PMID: 29803991 DOI: 10.1016/j.coph.2018.05.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 04/30/2018] [Accepted: 05/03/2018] [Indexed: 01/03/2023]
Abstract
Resistance of malignant glioma, including glioblastoma (GBM), to the chemotherapeutic temozolomide (TMZ) remains a key obstacle in treatment strategies. The gap junction protein connexin43 (Cx43) has complex roles in the establishment, progression, and persistence of malignant glioma. Recent findings demonstrate that connexins play an important role in the microenvironment of malignant glioma and that Cx43 is capable of conferring chemotherapeutic resistance to GBM cells. Carboxyl-terminal Cx43 peptidomimetics show therapeutic promise in overcoming TMZ resistance via mechanisms that may include modulating junctional activity between tumor cells and peritumoral cells and/or downstream molecular signaling events mediated by Cx43 protein binding. High levels of intra-tumor and inter-tumor heterogeneity make it difficult to clearly define specific populations for Cx43-targeted therapy; hence, development of in vitro models that better mimic the microenvironment of malignant glioma, and the incorporation of patient-derived stem cells, could provide opportunities for patient-specific drug screening. This review summarizes recent advances in understanding the roles of Cx43 in malignant glioma, with a special focus on tumor microenvironment, TMZ resistance, and therapeutic opportunity offered by Cx43 peptidomimetics.
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Affiliation(s)
| | - Zhi Sheng
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA; Faculty of Health Science, Virginia Tech, Blacksburg, VA, USA; Department of Biological Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA; Department of Internal Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
| | - Christian C Naus
- Department of Cellular and Physiological Science, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Wun Chey Sin
- Department of Cellular and Physiological Science, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Robert G Gourdie
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA; Faculty of Health Science, Virginia Tech, Blacksburg, VA, USA; Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences, Blacksburg, VA, USA; Department of Emergency Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
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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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Dong L, Yang X, Gu W, Zhao K, Ge H, Zhou J, Bai X. Connexin 43 mediates PFOS-induced apoptosis in astrocytes. CHEMOSPHERE 2015; 132:8-16. [PMID: 25770831 DOI: 10.1016/j.chemosphere.2015.02.041] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 06/04/2023]
Abstract
Perfluorooctane sulfonate (PFOS) is a man-made environmental pollutant that is toxic to mammals. However, the neurotoxic effects of PFOS remain largely unexplored. In this study, we determined the role of an astrocyte specific gap junction protein, connexin 43 (Cx43), in PFOS-induced apoptosis. The rate of astrocyte apoptosis was higher in cortex astrocytes after PFOS treatment. These astrocytes also showed up-regulated expression of Cx43 and higher levels of cleaved caspase-3. Elevated ROS accumulation and decreased ΔΨm also confirmed the presence of PFOS-induced apoptosis. However, the exposure of astrocytes to PFOS together with carbenoxolone (CBX) significantly reduced both Cx43 and cleaved caspase-3 levels. These results indicate that Cx43 plays a proapoptotic role in PFOS-induced apoptosis in cortex astrocyte cells.
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Affiliation(s)
- Li Dong
- Institute for Environmental Health and Related Product Safety, Chinese Center for Disease Control and Prevention, 7 Panjiayuan Nanli Road, Chaoyang District, Beijing 100021, China.
| | - Xiaoyan Yang
- Institute for Environmental Health and Related Product Safety, Chinese Center for Disease Control and Prevention, 7 Panjiayuan Nanli Road, Chaoyang District, Beijing 100021, China
| | - Wen Gu
- Institute for Environmental Health and Related Product Safety, Chinese Center for Disease Control and Prevention, 7 Panjiayuan Nanli Road, Chaoyang District, Beijing 100021, China
| | - Kangfeng Zhao
- Institute for Environmental Health and Related Product Safety, Chinese Center for Disease Control and Prevention, 7 Panjiayuan Nanli Road, Chaoyang District, Beijing 100021, China
| | - Huizheng Ge
- Beijing Biodonor Biotech Ltd., 88 The 6th Kechuang Street, Incubation Center Room 303, 101111 Beijing, China
| | - Jianjun Zhou
- Beijing Biodonor Biotech Ltd., 88 The 6th Kechuang Street, Incubation Center Room 303, 101111 Beijing, China
| | - Xuetao Bai
- Institute for Environmental Health and Related Product Safety, Chinese Center for Disease Control and Prevention, 7 Panjiayuan Nanli Road, Chaoyang District, Beijing 100021, China.
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Chen W, Wang D, Du X, He Y, Chen S, Shao Q, Ma C, Huang B, Chen A, Zhao P, Qu X, Li X. Glioma cells escaped from cytotoxicity of temozolomide and vincristine by communicating with human astrocytes. Med Oncol 2015; 32:43. [PMID: 25631631 DOI: 10.1007/s12032-015-0487-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 01/23/2015] [Indexed: 12/14/2022]
Abstract
Resistance to chemotherapeutic drugs remains a great obstacle to successful treatment of gliomas. Understanding the mechanism of glioma chemoresistance is conducive to develop effective strategies to overcome resistance. Astrocytes are the major stromal cells in the brain and have been demonstrated to play a key role in the malignant phenotype of gliomas. However, little is known regarding its role in glioma chemoresistance. In our study, we established a co-culture system of human astrocytes and glioma in vitro to simulate tumor microenvironment. Our results showed that astrocytes significantly reduced glioma cell apoptosis induced by the chemotherapeutic drugs temozolomide and vincristine. This protective effect was dependent on direct contact between astrocytes and glioma cells through Cx43-GJC. Moreover, in human glioma specimens, we found astrocytes infiltrating around the tumor, with a reactive appearance, suggesting that these astrocytes would play the same chemoprotective effect on gliomas in vivo. Our results expand the understanding of the interaction between astrocytes and glioma cells and provide a possible explanation for unsatisfactory clinical outcomes of chemotherapeutic drugs. Cx43-GJC between astrocytes and glioma cells may be a potential target for overcoming chemoresistance in gliomas clinically.
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Affiliation(s)
- Weiliang Chen
- Department of Neurosurgery, Qilu Hospital of Shandong University and Brain Science Research Institute, Shandong University, Jinan, 250012, China
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Kim YJ, Kim J, Tian C, Lim HJ, Kim YS, Chung JH, Choung YH. Prevention of cisplatin-induced ototoxicity by the inhibition of gap junctional intercellular communication in auditory cells. Cell Mol Life Sci 2014; 71:3859-71. [PMID: 24623558 PMCID: PMC11113131 DOI: 10.1007/s00018-014-1594-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 02/02/2014] [Accepted: 02/21/2014] [Indexed: 12/14/2022]
Abstract
Cis-diamminedichloroplatinum (cisplatin) is an effective chemotherapeutic drug for cancer therapy. However, most patients treated with cisplatin are at a high risk of ototoxicity, which causes severe hearing loss. Inspired by the "Good Samaritan effect" or "bystander effect" from gap junction coupling, we investigated the role of gap junctions in cisplatin-induced ototoxicity as a potential therapeutic method. We showed that connexin 43 (Cx43) was highly expressed in House Ear Institute-Organ of Corti 1 (HEI-OC1) cells, mediating cell-cell communication. The viability of HEI-OC1 cells was greatly decreased by cisplatin treatment, and cisplatin-treated HEI-OC1 cells showed lower Cx43 expression compared to that of untreated HEI-OC1 cells. In particular, high accumulation of Cx43 was observed around the nucleus of cisplatin-treated cells, whereas scattered punctuate expression of Cx43 was observed in the cytoplasm and membrane in normal cells, suggesting that cisplatin may interrupt the normal gap junction communication by inhibiting the trafficking of Cx43 to cell membranes in HEI-OC1 cells. Interestingly, we found that the inhibition of gap junction activity reduced cisplatin-induced apoptosis of auditory hair cells. Cx43 siRNA- or 18α-GA-treated HEI-OC1 cells showed higher cell viability compared to control HEI-OC1 cells during cisplatin treatment; this was also supported by fluorescence recovery after photobleaching studies. Inhibition of gap junction activity reduced recovery of calcein acetoxymethyl ester fluorescence compared to control cells. Additionally, analysis of the mechanisms involved demonstrated that highly activate extracellular signal-regulated kinase and protein kinase B, combined with inhibition of gap junctions may promote cell viability during cisplatin treatment.
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Affiliation(s)
- Yeon Ju Kim
- Department of Otolaryngology, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon, 443-721 Republic of Korea
| | - Jangho Kim
- Department of Biosystems & Biomaterials Science and Engineering, Seoul National University, Seoul, 151-742 Republic of Korea
| | - Chunjie Tian
- Department of Otolaryngology, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon, 443-721 Republic of Korea
| | - Hye Jin Lim
- Department of Otolaryngology, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon, 443-721 Republic of Korea
| | - Young Sun Kim
- Department of Otolaryngology, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon, 443-721 Republic of Korea
| | - Jong Hoon Chung
- Department of Biosystems & Biomaterials Science and Engineering, Seoul National University, Seoul, 151-742 Republic of Korea
| | - Yun-Hoon Choung
- Department of Otolaryngology, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon, 443-721 Republic of Korea
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He M, Li Y, Zhang L, Li L, Shen Y, Lin L, Zheng W, Chen L, Bian X, Ng HK, Tang L. Curcumin suppresses cell proliferation through inhibition of the Wnt/β-catenin signaling pathway in medulloblastoma. Oncol Rep 2014; 32:173-80. [PMID: 24858998 DOI: 10.3892/or.2014.3206] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 04/23/2014] [Indexed: 11/06/2022] Open
Abstract
Recently, the survival rate of medulloblastoma patients has greatly improved; yet, patients undergoing current treatment regimes suffer from serious therapy-related side-effects. The aim of the present study was to investigate the anticancer effects of curcumin on medulloblastoma cells by testing its capacity to suppress proliferation and regulate the Wnt/β-catenin pathway. In the present study, cell proliferation was determined by MTT assay. Cell cycle was observed by flow cytometry. The changes in the Wnt/β-catenin pathway were analyzed by immunofluorescence, western blot analysis and RT-PCR. Curcumin treatment resulted in a dose- and time-dependent inhibition of proliferation in the medulloblastoma cell line. Curcumin treatment arrested the cell-cycle at the G2/M phase. Furthermore, curcumin treatment led to activation of GSK-3β, reduced expression of β-catenin and its downstream target cyclin D1. The attenuation of the Wnt/β‑catenin pathway was due to the loss of nuclear β-catenin. In conclusion, curcumin can inhibit cell growth by suppressing the Wnt/β-catenin signaling pathway, and it has the potential to be developed as a therapeutic agent for medulloblastoma.
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Affiliation(s)
- Misi He
- Department of Pathophysiology, Chongqing Medical University, Chongqing, P.R. China
| | - Yu Li
- Department of Pathology, Insititute of Neuroscience, Chongqing Medical University, Chongqing, P.R. China
| | - Li Zhang
- Department of Pathophysiology, Chongqing Medical University, Chongqing, P.R. China
| | - Longjiang Li
- Department of Pathophysiology, Chongqing Medical University, Chongqing, P.R. China
| | - Yi Shen
- Department of Pathophysiology, Chongqing Medical University, Chongqing, P.R. China
| | - Ling Lin
- Department of Pathophysiology, Chongqing Medical University, Chongqing, P.R. China
| | - Weiping Zheng
- Experimental and Teaching Center, Chongqing Medical University, Chongqing, P.R. China
| | - Li Chen
- Experimental and Teaching Center, Chongqing Medical University, Chongqing, P.R. China
| | - Xiuwu Bian
- Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University, Chongqing, P.R. China
| | - Ho-Keung Ng
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong, SAR, P.R. China
| | - Li Tang
- Department of Pathophysiology, Chongqing Medical University, Chongqing, P.R. China
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Manoharan S, Palanimuthu D, Baskaran N, Silvan S. Modulating Effect of Lupeol on the Expression Pattern of Apoptotic Markers in 7, 12-Dimethylbenz(a)anthracene Induced Oral Carcinogenesis. Asian Pac J Cancer Prev 2012; 13:5753-7. [DOI: 10.7314/apjcp.2012.13.11.5753] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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