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Ye QW, Liu YJ, Li JQ, Han M, Bian ZR, Chen TY, Li JP, Liu SL, Zou X. GJA4 expressed on cancer associated fibroblasts (CAFs)-A 'promoter' of the mesenchymal phenotype. Transl Oncol 2024; 46:102009. [PMID: 38833783 PMCID: PMC11190749 DOI: 10.1016/j.tranon.2024.102009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 05/09/2024] [Accepted: 05/25/2024] [Indexed: 06/06/2024] Open
Abstract
BACKGROUND Colorectal cancer (CRC) is the third most common cancer worldwide. Connexin is a transmembrane protein involved in gap junctions (GJs) formation. Our previous study found that connexin 37 (Cx37), encoded by gap junction protein alpha 4 (GJA4), expressed on fibroblasts acts as a promoter of CRC and is closely related to epithelial-mesenchymal transition (EMT) and tumor immune microenvironment. However, to date, the mechanism concerning the malignancy of GJA4 in tumor stroma has not been studied. METHODS Hematoxylin-eosin (HE) and immunohistochemical (IHC) staining were used to validate the expression and localization of GJA4. Using single-cell analysis, enrichment analysis, spatial transcriptomics, immunofluorescence staining (IF), Sirius red staining, wound healing and transwell assays, western blotting (WB), Cell Counting Kit-8 (CCK8) assay and in vivo experiments, we investigated the possible mechanisms of GJA4 in promoting CRC. RESULTS We discovered that in CRC, GJA4 on fibroblasts is involved in promoting fibroblast activation and promoting EMT through a fibroblast-dependent pathway. Furthermore, GJA4 may act synergistically with M2 macrophages to limit T cell infiltration by stimulating the formation of an immune-excluded desmoplasic barrier. Finally, we found a significantly correlation between GJA4 and pathological staging (P < 0.0001) or D2 dimer (R = 0.03, P < 0.05). CONCLUSION We have identified GJA4 expressed on fibroblasts is actually a promoter of the tumor mesenchymal phenotype. Our findings suggest that the interaction between GJA4+ fibroblasts and M2 macrophages may be an effective target for enhancing tumor immunotherapy.
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Affiliation(s)
- Qian-Wen Ye
- Department of Oncology, Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing, Jiangsu, PR China; No.1 Clinical Medicial College, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, PR China
| | - Yuan-Jie Liu
- Department of Oncology, Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing, Jiangsu, PR China; No.1 Clinical Medicial College, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, PR China
| | - Jia-Qi Li
- Department of Oncology, Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing, Jiangsu, PR China; No.1 Clinical Medicial College, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, PR China
| | - Mei Han
- Department of Oncology, Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing, Jiangsu, PR China
| | - Ze-Ren Bian
- Department of Oncology, Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing, Jiangsu, PR China; No.1 Clinical Medicial College, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, PR China
| | - Tian-Yuan Chen
- Department of Oncology, Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing, Jiangsu, PR China; No.1 Clinical Medicial College, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, PR China
| | - Jie-Pin Li
- Jiangsu Province Key Laboratory of Tumor Systems Biology and Chinese Medicine, Nanjing, Jiangsu, PR China
| | - Shen-Lin Liu
- Department of Oncology, Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing, Jiangsu, PR China.
| | - Xi Zou
- Department of Oncology, Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing, Jiangsu, PR China; Jiangsu Province Key Laboratory of Tumor Systems Biology and Chinese Medicine, Nanjing, Jiangsu, PR China.
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da Fonseca IIM, Nagamine MK, Sato A, Rossatto-Jr CA, Yeh ES, Dagli MLZ. Inhibitory Effects of Alpha-Connexin Carboxyl-Terminal Peptide on Canine Mammary Epithelial Cells: A Study on Benign and Malignant Phenotypes. Cancers (Basel) 2024; 16:820. [PMID: 38398211 PMCID: PMC10887206 DOI: 10.3390/cancers16040820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 02/10/2024] [Accepted: 02/16/2024] [Indexed: 02/25/2024] Open
Abstract
Mammary cancer is highly prevalent in non-castrated female dogs. Cell-to-cell communication is an important mechanism to maintain homeostasis, and connexins are proteins that assemble to form the communicating gap junctions. In many cancers, communication capacity is reduced; several approaches are being tested in order to increase the communication capacity in cancer cells and, therefore, alter their viability. This study analyzed the effects of the alpha-connexin carboxyl-terminal peptide (αCT1) on canine mammary non-neoplastic and neoplastic epithelial cells. Seven canine epithelial mammary cell lines were used. Among these, one was a normal canine epithelial mammary cell line (LOEC-NMG), two canine mammary adenomas (LOEC-MAd1 and LOEC-MAd2), and four canine mammary adenocarcinomas (LOEC-MCA1, LOEC-MCA2, LOEC-MCA3 and CF41). The αCT1 corresponds to a short Cx43 C-terminal sequence linked to an internalization sequence called the antennapedia. After 24 h of incubation, the medium containing different αCT1 peptide concentrations was added to the cells, and only the culture medium was used for control. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test was used to quantify cell viability before treatment and 48, 72, and 96 h after the treatment. Results showed that the normal mammary epithelial cell line (LOEC-NMG) was resistant to treatment with αCT1, which is consistent with a previous study on human mammary cell lines. One of the adenoma cell lines (LOEC-MAd2) was also resistant to treatment with αCT1, although the other (LOEC-MAd1) was susceptible to treatment, mostly at 72 h after treatment. Regarding the four canine adenocarcinoma cell lines, they differ regarding the susceptibility to the treatment with αCT1. Three cell lines, canine mixed adenocarcinoma (LOEC-MCA1), canine complex adenocarcinoma (LOEC-MCA2), and commercial canine mammary adenocarcinoma cell line CF41, were susceptible to treatment with αCT1, while one canine mammary adenocarcinoma cell line (LOEC-MCA3) was resistant to treatment. In most αCT1 treated cell lines, Cx43 was strongly detected in cell membranes by immunofluorescence. We propose that αCT1 restored the cell-to-cell communication capacity of neoplastic cells and induced inhibitory effects on cell viability.
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Affiliation(s)
- Ivone Izabel Mackowiak da Fonseca
- Laboratory of Experimental and Comparative Oncology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil; (I.I.M.d.F.); (M.K.N.); (A.S.); (C.A.R.-J.)
| | - Marcia Kazumi Nagamine
- Laboratory of Experimental and Comparative Oncology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil; (I.I.M.d.F.); (M.K.N.); (A.S.); (C.A.R.-J.)
| | - Ayami Sato
- Laboratory of Experimental and Comparative Oncology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil; (I.I.M.d.F.); (M.K.N.); (A.S.); (C.A.R.-J.)
- Institute of Life Innovation Studies, Toyo University, Tokyo 374-0193, Japan
| | - Carlos Alberto Rossatto-Jr
- Laboratory of Experimental and Comparative Oncology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil; (I.I.M.d.F.); (M.K.N.); (A.S.); (C.A.R.-J.)
| | - Elizabeth Shinmay Yeh
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Melvin and Bren Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Maria Lucia Zaidan Dagli
- Laboratory of Experimental and Comparative Oncology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil; (I.I.M.d.F.); (M.K.N.); (A.S.); (C.A.R.-J.)
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Wang DQ, Wang YY, Shi YL, Zeng B, Lin ZJ, Deng Q, Ming J. Correlation between connexin 43 expression in circulating tumor cells and biological characteristics of breast cancer. Heliyon 2023; 9:e18697. [PMID: 37583757 PMCID: PMC10424078 DOI: 10.1016/j.heliyon.2023.e18697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 07/20/2023] [Accepted: 07/25/2023] [Indexed: 08/17/2023] Open
Abstract
Background Connexin 43 (Cx43) has been closely linked to the occurrence and progression of breast cancer. Distant metastasis of breast cancer is aided by the epithelial-mesenchymal transition of circulating tumor cells (CTCs). However, the impact of Cx43 expression on CTCs and the extent of its role in the disease remain unclear. Methods We determined CTCs in 156 patients, who had breast cancer with a disease course of two or more years. We also measured the expression of Cx43 in the CTCs. The CTCs were detected in the blood of 139 of these patients. These 139 patients were divided into two groups: the Cx43 group and the non-Cx43 group based on their Cx43 expression. Results Overall, Cx43 expression was found in 83 of the 139 patients (59.7%, 83/139 cases). The two groups significantly differed in terms of the number of mixed biphenotypic type CTCs and the total number of CTCs (P < 0.05). There were significant correlations between Cx43 expression and Ki67 expression, tumor size, lymph node metastasis, and TNM stage (P < 0.05 for all). The data suggested that patients with Cx43 expression had a higher risk of distant metastasis and had later-stage disease. The difference in Cx43 expression between patients with and without epidermal growth factor receptor 2 (Her2) overexpression was statistically significant (P < 0.05). The difference in disease-free survival (DFS) between the two groups was statistically significant (P = 0.03), and the Cx43 group had a shorter duration of DFS. Univariate Cox regression analysis revealed that Cx43 expression, Her2 expression, and tumor size were significantly correlated with DFS (P = 0.03, 0.0023, and 0.01, respectively). Conclusion Cx43 expression in the CTCs of patients with breast cancer is a cancer-promoting factor.
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Affiliation(s)
- Dan-Qing Wang
- Department of Breast and Thyroid Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, People's Republic of China
| | - Yuan-Yuan Wang
- Department of Emergency, Xi'an Central Hospital, Xi'an 710003, People's Republic of China
| | - Yan-Ling Shi
- Department of Breast and Thyroid Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, People's Republic of China
| | - Bin Zeng
- Department of Breast and Thyroid Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, People's Republic of China
| | - Zi-Jing Lin
- Department of Breast and Thyroid Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, People's Republic of China
| | - Qin Deng
- Department of Breast and Thyroid Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, People's Republic of China
| | - Jia Ming
- Department of Breast and Thyroid Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, People's Republic of China
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Cx43 phosphorylation sites regulate pancreatic cancer metastasis. Oncogene 2021; 40:1909-1920. [PMID: 33603164 PMCID: PMC8191514 DOI: 10.1038/s41388-021-01668-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 01/03/2021] [Accepted: 01/18/2021] [Indexed: 01/30/2023]
Abstract
Pancreatic ductal adenocarcinoma (PDA) is aggressive, highly metastatic and characterized by a robust desmoplasia. Connexin proteins that form gap junctions have been implicated in tumor suppression for over 30 years. Cx43, the most widely expressed connexin, regulates cell behaviors, including migration and proliferation. Thus, we hypothesized that Cx43 could regulate PDA progression. Phosphorylation of Cx43 by Casein Kinase 1 (CK1) regulates gap junction assembly. We interbred the well-established KrasLSL-G12D/+;p48Cre/+ (KC) mouse model of PDA with homozygous "knock-in" mutant Cx43 mice bearing amino acid substitution at CK1 sites (Cx43CK1A) and found profound and surprising effects on cancer progression. Crossing the Cx43CK1A mouse onto the KC background (termed KC;CxCK1A) led to significant extension of lifespan, from a median of 370 to 486 days (p = 0.03) and a decreased incidence of metastasis (p = 0.045). However, when we examined early stages of disease, we found more rapid onset of tissue remodeling in the KC;CxCK1A mouse followed by divergence to a cystic phenotype. During tumorigenesis, gap junctions are increasingly present in stromal cells of the KC mice but are absent from the KC;Cx43CK1A mice. Tail vein metastasis assays with cells derived from KC or KC;CxCK1A tumors showed that KC;CxCK1A cells could efficiently colonize the lung and downregulate Cx43 expression, arguing that inhibition of metastasis was not occurring at the distal site. Instead, stromal gap junctions, their associated signaling events or other unknown Cx43-dependent events facilitate metastatic capacity in the primary tumor.
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Ren D, Zheng P, Feng J, Gong Y, Wang Y, Duan J, Zhao L, Deng J, Chen H, Zou S, Hong T, Chen W. Overexpression of Astrocytes-Specific GJA1-20k Enhances the Viability and Recovery of the Neurons in a Rat Model of Traumatic Brain Injury. ACS Chem Neurosci 2020; 11:1643-1650. [PMID: 32401478 DOI: 10.1021/acschemneuro.0c00142] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Traumatic brain injury (TBI) is a devastating actuality in clinics worldwide. It is estimated that approximately 10 million people among the world suffer from TBI each year, and a considerable number of patients will be temporarily or permanently disabled or even die due to this disease. Astrocytes play a very important role in the repair of brain tissue after TBI, including the formation of a neuroprotective barrier, inhibition of brain edema, and inhibition of normal nerve cell apoptosis. However, the detailed mechanism underlying this protective effect is still unclear. To investigate the regulatory factors of astrocytes to other neurons post-TBI, we established a TBI rat model and used the AAV to mediate the overexpression of GJA1-20k in astrocytes of rats. And functionally, the specific overexpression of GJA1-20k in astrocytes promoted the viability and recovery of neurons in TBI. Mechanistically, the astrocytes-specific upregulation of GJA1-20k protected the function of mitochondria in neurons of FPI rats, thus suppressing the apoptosis of the damaged neurons. We hereby reported that astrocytes-specific overexpression of GJA1-20k enhanced the viability and recovery of the neurons in TBI through regulating their mitochondrial function.
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Affiliation(s)
- Dabin Ren
- Department of Neurosurgery, the People’s Hospital of Shanghai Pudong New Area Affiliated to Shanghai University of Medicine and Health Sciences, Shanghai 201299, P. R. China
| | - Ping Zheng
- Department of Neurosurgery, the People’s Hospital of Shanghai Pudong New Area Affiliated to Shanghai University of Medicine and Health Sciences, Shanghai 201299, P. R. China
| | - Jiugeng Feng
- Department of Neurosurgery, the First Affiliated Hospital of Nanchang University, Nanchang 330008, Jiangxi, P. R. China
| | - Yuqin Gong
- Department of Operation Room, the Second Affiliated Hospital of Nanchang University, Nanchang 330009, Jiangxi, P. R. China
| | - Yang Wang
- Department of Neurosurgery, the First Affiliated Hospital of Nanchang University, Nanchang 330008, Jiangxi, P. R. China
| | - Jian Duan
- Department of Neurosurgery, the First Affiliated Hospital of Nanchang University, Nanchang 330008, Jiangxi, P. R. China
| | - Lin Zhao
- Department of Neurosurgery, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210009, Jiangsu China
| | - Jun Deng
- Department of Emergency@Trauma Center, the First Affiliated Hospital of Nanchang University, Nanchang 330008, Jiangxi, P. R. China
| | - Haiming Chen
- Department of Emergency@Trauma Center, the First Affiliated Hospital of Nanchang University, Nanchang 330008, Jiangxi, P. R. China
| | - Shufeng Zou
- Department of Neurosurgery, the First Affiliated Hospital of Nanchang University, Nanchang 330008, Jiangxi, P. R. China
| | - Tao Hong
- Department of Neurosurgery, the First Affiliated Hospital of Nanchang University, Nanchang 330008, Jiangxi, P. R. China
| | - Wei Chen
- Department of Neurosurgery, the People’s Hospital of Shanghai Pudong New Area Affiliated to Shanghai University of Medicine and Health Sciences, Shanghai 201299, P. R. China
- Department of Emergency@Trauma Center, the First Affiliated Hospital of Nanchang University, Nanchang 330008, Jiangxi, P. R. China
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Gregory M, Cyr DG. Effects of prostaglandin E2 on gap junction protein alpha 1 in the rat epididymis. Biol Reprod 2020; 100:123-132. [PMID: 30060123 DOI: 10.1093/biolre/ioy171] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 07/25/2018] [Indexed: 12/20/2022] Open
Abstract
Gap junctions are responsible for intercellular communication. In the adult mammalian epididymis, gap junction protein alpha 1 (GJA1) is localized between basal and either principal or clear cells. GJA1 levels and localization change during the differentiation of basal cells. The present objective was to determine the role of basal cells and prostaglandin E2 (PGE2) on GJA1 in the rat epididymis. Prior to basal cell differentiation, GJA1 is colocalized with TJP1 at the apical lateral margins between adjacent epithelial cells. When basal cells are present, GJA1 becomes associated between basal and principal cells, where it is primarily immunolocalized until adulthood. Basal cells express TP63, differentiate from epithelial cells, and produce prostaglandin-endoperoxide synthase 1 by 21 days of age. Prior to day 21, GJA1and TP63 are not strongly associated at the apical region. However, by day 28, TP63-positive basal cells migrate to the base of the epithelium, and also express GJA1. To assess effects of PGE2 on GJA1, rat caput epididymal (RCE) cells were exposed to PGE2 (50 μM) for 3 h. PGE2 increased levels of Gja1 mRNA in RCE cells, while levels of Gjb1, Gjb2, Gjb4, and GjB5 were unaltered. Furthermore, PGE2 increased protein levels of GJA1, phospho-GJA1, phospho-AKT, CTNNB1, and phospho-CTNNB1. Total AKT and the tight junction protein claudin1 were also not altered by PGE2. Data suggest that development of the epididymal epithelium and differentiation of epididymal basal cells regulate the targeting of GJA1, and that this appears to be mediated by PGE2.
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Affiliation(s)
- Mary Gregory
- Laboratory for Reproductive Toxicology, INRS-Institut Armand-Frappier, University of Quebec, Laval, Quebec, Canada
| | - Daniel G Cyr
- Laboratory for Reproductive Toxicology, INRS-Institut Armand-Frappier, University of Quebec, Laval, Quebec, Canada
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Iwamoto M, Takashima M, Ohtubo Y. A subset of taste receptor cells express biocytin-permeable channels activated by reducing extracellular Ca 2+ concentration. Eur J Neurosci 2020; 51:1605-1623. [PMID: 31912931 DOI: 10.1111/ejn.14672] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 12/03/2019] [Accepted: 01/02/2020] [Indexed: 12/11/2022]
Abstract
Taste receptor cells (type II cells) transmit taste information to taste nerve fibres via ATP-permeable channels, including calcium homeostasis modulator (CALHM), connexin and/or pannexin1 channels, via the paracrine release of adenosine triphosphate (ATP) as a predominant transmitter. In the present study, we demonstrate that extracellular Ca2+ -dependent biocytin-permeable channels are present in a subset of type II cells in mouse fungiform taste buds using biocytin uptake, immunohistochemistry and in situ whole-cell recordings. Type II cells were labelled with biocytin in an extracellular Ca2+ concentration ([Ca2+ ]out )-sensitive manner. We found that the ratio of biocytin-labelled type II cells to type II cells per taste bud was approximately 20% in 2 mM Ca2+ saline, and this ratio increased to approximately 50% in nominally Ca2+ -free saline. The addition of 300 µM GdCl3 , which inhibits various channels including CALHM1 channels, significantly inhibited biocytin labelling in nominally Ca2+ -free saline, whereas the addition of 20 µM ruthenium red did not. Moreover, Cs+ -insensitive currents increased in nominally Ca2+ -free saline in approximately 40% of type II cells. These increased currents appeared at a potential of above -35 mV, reversed at approximately +10 mV and increased with depolarization. These results suggest that biocytin labels type II cells via ion channels activated by [Ca2+ ]out reduction, probably "CALHM-like" channels, on the basolateral membrane and that taste receptor cells can be categorized into two groups based on differences in the expression levels of [Ca2+ ]out -dependent biocytin-permeable channels. These data indicate electrophysiological and pharmacologically relevant properties of biocytin-permeable channels and suggest their contributions to taste signal transduction.
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Affiliation(s)
- Masafumi Iwamoto
- Graduate school of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu-shi, Japan
| | - Madoka Takashima
- Graduate school of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu-shi, Japan
| | - Yoshitaka Ohtubo
- Graduate school of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu-shi, Japan
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A Barter Economy in Tumors: Exchanging Metabolites through Gap Junctions. Cancers (Basel) 2019; 11:cancers11010117. [PMID: 30669506 PMCID: PMC6356692 DOI: 10.3390/cancers11010117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 01/16/2019] [Accepted: 01/18/2019] [Indexed: 02/07/2023] Open
Abstract
To produce physiological functions, many tissues require their cells to be connected by gap junctions. Such diffusive coupling is important in establishing a cytoplasmic syncytium through which cells can exchange signals, substrates and metabolites. Often the benefits of connectivity become apparent solely at the multicellular level, leading to the notion that cells work for a common good rather than exclusively in their self-interest. In some tumors, gap junctional connectivity between cancer cells is reduced or absent, but there are notable cases where it persists or re-emerges in late-stage disease. Diffusive coupling will blur certain phenotypic differences between cells, which may seem to go against the establishment of population heterogeneity, a central pillar of cancer that stems from genetic instability. Here, building on our previous measurements of gap junctional coupling between cancer cells, we use a computational model to simulate the role of connexin-assembled channels in exchanging lactate and bicarbonate ions down their diffusion gradients. Based on the results of these simulations, we propose that an overriding benefit of gap junctional connectivity may relate to lactate/bicarbonate exchange, which would support an elevated metabolic rate in hypoxic tumors. In this example of barter, hypoxic cancer cells provide normoxic neighbors with lactate for mitochondrial oxidation; in exchange, bicarbonate ions, which are more plentiful in normoxic cells, are supplied to hypoxic neighbors to neutralize the H+ ions co-produced glycolytically. Both cells benefit, and so does the tumor.
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Glucose and Lactate Transport in Pancreatic Cancer: Glycolytic Metabolism Revisited. JOURNAL OF ONCOLOGY 2018; 2018:6214838. [PMID: 30631356 PMCID: PMC6304534 DOI: 10.1155/2018/6214838] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 11/13/2018] [Accepted: 11/21/2018] [Indexed: 01/09/2023]
Abstract
Membrane transporters fulfill essential roles in maintaining normal cellular function in health. In cancer, transporters likewise facilitate the aberrant characteristics typical of proliferating tumor cells. Pancreatic ductal adenocarcinoma is remarkable in its aggressiveness, and its metabolism is supported by a variety of membrane transporters. Glucose transporter 1 is upregulated in pancreatic cancer, enables rapid cellular uptake of glucose, and contributes to the invasiveness and metastatic ability of the disease. Likewise, the machinery of glycolysis, enzymes such as pyruvate kinase type M2 and hexokinase 2, is particularly active and ultimately leads to both lactate and tumor formation. Lactic acid channels and transporters include monocarboxylate transporters 1 and 4, connexin43, and CD147. In conjunction with glucose transporters and glycolytic metabolism, lactic acid transport helps perpetuate tumor cell metabolism and contributes to the formation of the unique tumor microenvironment in pancreatic cancer. These transporters may serve as potential therapeutic targets.
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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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Fu Y, Zhang SS, Xiao S, Basheer WA, Baum R, Epifantseva I, Hong T, Shaw RM. Cx43 Isoform GJA1-20k Promotes Microtubule Dependent Mitochondrial Transport. Front Physiol 2017; 8:905. [PMID: 29163229 PMCID: PMC5682029 DOI: 10.3389/fphys.2017.00905] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 10/25/2017] [Indexed: 01/26/2023] Open
Abstract
Connexin 43 (Cx43, encoded by GJA1) is a cell-cell communication gap junction protein expressed in all organ systems. It was recently found that GJA1 mRNA undergoes alternative translation to generate N-terminal truncated isoforms, of which GJA1-20k is the most abundant. Here we report a surprising finding that, unlike full length GJA1-43k, GJA1-20k has a strong tropism for mitochondria. Exploring function, we found that GJA1-20k appears to be an organelle chaperone and that overexpression of GJA1-20k is sufficient to rescue mitochondrial localization to the cell periphery upon exposure to hydrogen peroxide, which effectively limits the network fragmentation that occurs with oxidative stress. By high-resolution fluorescent imaging and electron microscopy, we determined that GJA1-20k is enriched at the interface between mitochondria and microtubules, appearing to load organelles for transport. Mutagenesis experiments revealed that although the microtubule-binding domain (MTBD) in GJA1-20k is not necessary for protein localization to mitochondria, the MTBD is essential for GJA1-20k to facilitate mitochondrial transport and maintain mitochondrial localization at the periphery. These results reveal an unexpected role for the alternatively translated isoform of the Cx43 gap junction protein, GJA1-20k, which is to facilitate microtubule-based mitochondrial transport and to maintain mitochondrial network integrity during cellular stress.
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Affiliation(s)
- Ying Fu
- Cedars-Sinai Medical Center, Cedars-Sinai Heart Institute, Los Angeles, CA, United States
| | - Shan-Shan Zhang
- Cedars-Sinai Medical Center, Cedars-Sinai Heart Institute, Los Angeles, CA, United States
| | - Shaohua Xiao
- Cedars-Sinai Medical Center, Cedars-Sinai Heart Institute, Los Angeles, CA, United States
| | - Wassim A Basheer
- Cedars-Sinai Medical Center, Cedars-Sinai Heart Institute, Los Angeles, CA, United States
| | - Rachel Baum
- Cedars-Sinai Medical Center, Cedars-Sinai Heart Institute, Los Angeles, CA, United States
| | - Irina Epifantseva
- Cedars-Sinai Medical Center, Cedars-Sinai Heart Institute, Los Angeles, CA, United States
| | - TingTing Hong
- Cedars-Sinai Medical Center, Cedars-Sinai Heart Institute, Los Angeles, CA, United States.,Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Robin M Shaw
- Cedars-Sinai Medical Center, Cedars-Sinai Heart Institute, Los Angeles, CA, United States.,Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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12
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Dovmark TH, Hulikova A, Niederer SA, Vaughan-Jones RD, Swietach P. Normoxic cells remotely regulate the acid-base balance of cells at the hypoxic core of connexin-coupled tumor growths. FASEB J 2017; 32:83-96. [PMID: 28883041 DOI: 10.1096/fj.201700480r] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/14/2017] [Indexed: 12/19/2022]
Abstract
ATP fuels the removal of metabolic end-products, including H+ ions that profoundly modulate biological activities. Energetic resources in hypoxic tumor regions are constrained by low-yielding glycolysis, and any means of reducing the cost of acid extrusion, without compromising pH homeostasis, would therefore be advantageous for cancer cells. Some cancers express connexin channels that allow solute exchange between cells, and we propose that, via this route, normoxic cells supply hypoxic neighbors with acid-neutralizing HCO3- ions. This hypothesis was tested by imaging cytoplasmic pH in spheroidal tissue growths of connexin43-positive pancreatic cancer Colo357 cells during light-controlled H+ uncaging at the hypoxic core. Cytoplasmic acid retention at the core was halved in the presence of CO2/HCO3-, but this process requires a restorative HCO3- flux. The effect of CO2/HCO3- was ablated by connexin43 inhibition or knockdown. In connexin-decoupled spheroids, 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS), an inhibitor of HCO3- uptake, had no effect on cytoplasmic [H+] in the H+-uncaging region, indicating that DIDS-sensitive transport is not an adequate pH-regulatory strategy therein. With intact connexin-coupling, acid retention at the core increased upon DIDS treatment, indicating that HCO3- ions are taken up actively by peripheral cells and then transmitted passively to cells at the hypoxic core. Thus, the energetic burden of pH regulation is offloaded from hypoxic cells onto metabolically altruistic normoxic neighbors.-Dovmark, T. H., Hulikova, A., Niederer, S. A., Vaughan-Jones, R. D., Swietach, P. Normoxic cells remotely regulate the acid-base balance of cells at the hypoxic core of connexin-coupled tumor growths.
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Affiliation(s)
- Tobias H Dovmark
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom, and
| | - Alzbeta Hulikova
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom, and
| | - Steven A Niederer
- Division of Imaging Sciences and Biomedical Engineering, St. Thomas' Hospital, London, United Kingdom
| | - Richard D Vaughan-Jones
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom, and
| | - Pawel Swietach
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom, and
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13
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Mesnil M, Aasen T, Boucher J, Chépied A, Cronier L, Defamie N, Kameritsch P, Laird DW, Lampe PD, Lathia JD, Leithe E, Mehta PP, Monvoisin A, Pogoda K, Sin WC, Tabernero A, Yamasaki H, Yeh ES, Dagli MLZ, Naus CC. An update on minding the gap in cancer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:237-243. [PMID: 28655619 DOI: 10.1016/j.bbamem.2017.06.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/22/2017] [Accepted: 06/23/2017] [Indexed: 01/08/2023]
Abstract
This article is a report of the "International Colloquium on Gap junctions: 50Years of Impact on Cancer" that was held 8-9 September 2016, at the Amphitheater "Pôle Biologie Santé" of the University of Poitiers (Poitiers, France). The colloquium was organized by M Mesnil (Université de Poitiers, Poitiers, France) and C Naus (University of British Columbia, Vancouver, Canada) to celebrate the 50th anniversary of the seminal work published in 1966 by Loewenstein and Kanno [Intercellular communication and the control of tissue growth: lack of communication between cancer cells, Nature, 116 (1966) 1248-1249] which initiated studies on the involvement of gap junctions in carcinogenesis. During the colloquium, 15 participants presented reviews or research updates in the field which are summarized below.
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Affiliation(s)
- Marc Mesnil
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France.
| | - Trond Aasen
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain
| | - Jonathan Boucher
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France
| | - Amandine Chépied
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France
| | - Laurent Cronier
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France
| | - Norah Defamie
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France
| | - Petra Kameritsch
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, München, Germany
| | - Dale W Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario N6A 5C1, Canada
| | - Paul D Lampe
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Justin D Lathia
- Cleveland Clinic, Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA
| | - Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, and Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, NO-0424 Oslo, Norway
| | - Parmender P Mehta
- Department of Biochemistry and Molecular Biology, University of Nebraska, Medical Center, Omaha, NE 68198, USA
| | - Arnaud Monvoisin
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France
| | - Kristin Pogoda
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, München, Germany
| | - Wun-Chey Sin
- Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Arantxa Tabernero
- Departamento de Bioquímica y Biología Molecular, Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Salamanca 37007, Spain
| | | | - Elizabeth S Yeh
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29412, USA
| | - Maria Lucia Zaidan Dagli
- Laboratory of Experimental and Comparative Oncology, School of Veterinary Medicine and Animal Science of the University of São Paulo, São Paulo, SP CEP 05508-900, Brazil
| | - Christian C Naus
- Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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14
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Connexin's Connection in Breast Cancer Growth and Progression. Int J Cell Biol 2016; 2016:9025905. [PMID: 27642298 PMCID: PMC5011527 DOI: 10.1155/2016/9025905] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 07/18/2016] [Indexed: 12/26/2022] Open
Abstract
Gap junctions are cell-to-cell junctions that are located in the basolateral surface of two adjoining cells. A gap junction channel is composed of a family of proteins called connexins. Gap junction channels maintain intercellular communication between two cells through the exchange of ions, small metabolites, and electrical signals. Gap junction channels or connexins are widespread in terms of their expression and function in maintaining the development, differentiation, and homeostasis of vertebrate tissues. Gap junction connexins play a major role in maintaining intercellular communication among different cell types of normal mammary gland for proper development and homeostasis. Connexins have also been implicated in the pathogenesis of breast cancer. Differential expression pattern of connexins and their gap junction dependent or independent functions provide pivotal cross talk of breast tumor cells with the surrounding stromal cell in the microenvironment. Substantial research from the last 20 years has accumulated ample evidences that allow us a better understanding of the roles that connexins play in the tumorigenesis of primary breast tumor and its metastatic progression. This review will summarize the knowledge about the connexins and gap junction activities in breast cancer highlighting the differential expression and functional dynamics of connexins in the pathogenesis of the disease.
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15
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Esseltine JL, Laird DW. Next-Generation Connexin and Pannexin Cell Biology. Trends Cell Biol 2016; 26:944-955. [PMID: 27339936 DOI: 10.1016/j.tcb.2016.06.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 01/17/2023]
Abstract
Connexins and pannexins are two families of large-pore channel forming proteins that are capable of passing small signaling molecules. While connexins serve the seminal task of direct gap junctional intercellular communication, pannexins are far less understood but function primarily as single membrane channels in autocrine and paracrine signaling. Advancements in connexin and pannexin biology in recent years has revealed that in addition to well-described classical functions at the plasma membrane, exciting new evidence suggests that connexins and pannexins participate in alternative pathways involving multiple intracellular compartments. Here we briefly highlight classical functions of connexins and pannexins but focus our attention mostly on the transformative findings that suggest that these channel-forming proteins may serve roles far beyond our current understandings.
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Affiliation(s)
- Jessica L Esseltine
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
| | - Dale W Laird
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada.
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16
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Connexin 43, breast cancer tumor suppressor: Missed connections? Cancer Lett 2016; 374:117-126. [DOI: 10.1016/j.canlet.2016.02.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 01/28/2016] [Accepted: 02/03/2016] [Indexed: 12/21/2022]
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17
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Korsten H, Ziel-van der Made ACJ, van Weerden WM, van der Kwast T, Trapman J, Van Duijn PW. Characterization of Heterogeneous Prostate Tumors in Targeted Pten Knockout Mice. PLoS One 2016; 11:e0147500. [PMID: 26807730 PMCID: PMC4726760 DOI: 10.1371/journal.pone.0147500] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/05/2016] [Indexed: 11/18/2022] Open
Abstract
Previously, we generated a preclinical mouse prostate tumor model based on PSA-Cre driven inactivation of Pten. In this model homogeneous hyperplastic prostates (4-5m) developed at older age (>10m) into tumors. Here, we describe the molecular and histological characterization of the tumors in order to better understand the processes that are associated with prostate tumorigenesis in this targeted mouse Pten knockout model. The morphologies of the tumors that developed were very heterogeneous. Different histopathological growth patterns could be identified, including intraductal carcinoma (IDC), adenocarcinoma and undifferentiated carcinoma, all strongly positive for the epithelial cell marker Cytokeratin (CK), and carcinosarcomas, which were negative for CK. IDC pattern was already detected in prostates of 7-8 month old mice, indicating that it could be a precursor stage. At more than 10 months IDC and carcinosarcoma were most frequently observed. Gene expression profiling discriminated essentially two molecular subtypes, denoted tumor class 1 (TC1) and tumor class 2 (TC2). TC1 tumors were characterized by high expression of epithelial markers like Cytokeratin 8 and E-Cadherin whereas TC2 tumors showed high expression of mesenchyme/stroma markers such as Snail and Fibronectin. These molecular subtypes corresponded with histological growth patterns: where TC1 tumors mainly represented adenocarcinoma/intraductal carcinoma, in TC2 tumors carcinosarcoma was the dominant growth pattern. Further molecular characterization of the prostate tumors revealed an increased expression of genes associated with the inflammatory response. Moreover, functional markers for senescence, proliferation, angiogenesis and apoptosis were higher expressed in tumors compared to hyperplasia. The highest expression of proliferation and angiogenesis markers was detected in TC2 tumors. Our data clearly showed that in the genetically well-defined PSA-Cre;Pten-loxP/loxP prostate tumor model, histopathological, molecular and biological heterogeneity occurred during later stages of tumor development.
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MESH Headings
- Adenocarcinoma/chemistry
- Adenocarcinoma/genetics
- Adenocarcinoma/pathology
- Animals
- Apoptosis/genetics
- Biomarkers
- Biomarkers, Tumor
- Cadherins/analysis
- Carcinoma/chemistry
- Carcinoma/genetics
- Carcinoma/pathology
- Carcinosarcoma/chemistry
- Carcinosarcoma/genetics
- Carcinosarcoma/pathology
- Cellular Senescence/genetics
- Disease Progression
- Epithelial Cells/chemistry
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic
- Inflammation/genetics
- Keratins/analysis
- Male
- Mesoderm/chemistry
- Mice
- Mice, Inbred Strains
- Mice, Knockout
- Neoplasm Proteins/analysis
- Neovascularization, Pathologic/genetics
- Neovascularization, Pathologic/pathology
- PTEN Phosphohydrolase/deficiency
- Prostatic Hyperplasia/genetics
- Prostatic Hyperplasia/pathology
- Prostatic Neoplasms/chemistry
- Prostatic Neoplasms/classification
- Prostatic Neoplasms/genetics
- Prostatic Neoplasms/pathology
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- RNA, Neoplasm/biosynthesis
- RNA, Neoplasm/genetics
- Stromal Cells/chemistry
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Affiliation(s)
- Hanneke Korsten
- Department of Pathology, Josephine Nefkens Institute, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Wytske M. van Weerden
- Department of Urology, Josephine Nefkens Institute, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Theo van der Kwast
- Department of Pathology, Josephine Nefkens Institute, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Jan Trapman
- Department of Pathology, Josephine Nefkens Institute, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Petra W. Van Duijn
- Department of Pathology, Josephine Nefkens Institute, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Urology, Josephine Nefkens Institute, Erasmus Medical Center, Rotterdam, The Netherlands
- * E-mail:
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18
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Abstract
The pancreas produces enzymes with a digestive function and hormones with a metabolic function, which are produced by distinct cell types of acini and islets, respectively. Within these units, secretory cells coordinate their functioning by exchanging information via signals that flow in the intercellular spaces and are generated either at distance (several neural and hormonal inputs) or nearby the pancreatic cells themselves (inputs mediated by membrane ionic-specific channels and by ionic- and metabolite-permeant pannexin channels and connexin "hemichannels"). Pancreatic secretory cells further interact via the extracellular matrix of the pancreas (inputs mediated by integrins) and directly with neighboring cells, by mechanisms that do not require extracellular mediators (inputs mediated by gap and tight junction channels). Here, we review the expression and function of the connexins and pannexins that are expressed by the main secretory cells of the exocrine and endocrine pancreatic cells. Available data show that the patterns of expression of these proteins differ in acini and islets, supporting distinct functions in the physiological secretion of pancreatic enzymes and hormones. Circumstantial evidence further suggests that alterations in the signaling provided by these proteins are involved in pancreatic diseases.
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19
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Grek CL, Rhett JM, Bruce JS, Abt MA, Ghatnekar GS, Yeh ES. Targeting connexin 43 with α-connexin carboxyl-terminal (ACT1) peptide enhances the activity of the targeted inhibitors, tamoxifen and lapatinib, in breast cancer: clinical implication for ACT1. BMC Cancer 2015; 15:296. [PMID: 25881004 PMCID: PMC4407347 DOI: 10.1186/s12885-015-1229-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 03/19/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Treatment failure is a critical issue in breast cancer and identifying useful interventions that optimize current cancer therapies remains a critical unmet need. Expression and functional studies have identified connexins (Cxs), a family of gap junction proteins, as potential tumor suppressors. Studies suggest that Cx43 has a role in breast cancer cell proliferation, differentiation, and migration. Although pan-gap junction drugs are available, the lack of specificity of these agents increases the opportunity for off target effects. Consequently, a therapeutic agent that specifically modulates Cx43 would be beneficial and has not been tested in breast cancer. In this study, we now test an agent that specifically targets Cx43, called ACT1, in breast cancer. METHODS We evaluated whether direct modulation of Cx43 using a Cx43-directed therapeutic peptide, called ACT1, enhances Cx43 gap junctional activity in breast cancer cells, impairs breast cancer cell proliferation or survival, and enhances the activity of the targeted inhibitors tamoxifen and lapatinib. RESULTS Our results show that therapeutic modulation of Cx43 by ACT1 maintains Cx43 at gap junction sites between cell-cell membrane borders of breast cancer cells and augments gap junction activity in functional assays. The increase in Cx43 gap junctional activity achieved by ACT1 treatment impairs proliferation or survival of breast cancer cells but ACT1 has no effect on non-transformed MCF10A cells. Furthermore, treating ER+ breast cancer cells with a combination of ACT1 and tamoxifen or HER2+ breast cancer cells with ACT1 and lapatinib augments the activity of these targeted inhibitors. CONCLUSIONS Based on our findings, we conclude that modulation of Cx43 activity in breast cancer can be effectively achieved with the agent ACT1 to sustain Cx43-mediated gap junctional activity resulting in impaired malignant progression and enhanced activity of lapatinib and tamoxifen, implicating ACT1 as part of a combination regimen in breast cancer.
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Affiliation(s)
- Christina L Grek
- FirstString Research, Inc., 300 W. Coleman Blvd., Suite 203, Mount Pleasant, SC, USA.
| | - Joshua Matthew Rhett
- Department of Surgery, Division of General Surgery, Medical University of South Carolina, Charleston, SC, USA.
| | - Jaclynn S Bruce
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, 173 Ashley Ave, BSB358, MSC509, Charleston, SC, 29425, USA.
| | - Melissa A Abt
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, 173 Ashley Ave, BSB358, MSC509, Charleston, SC, 29425, USA.
| | - Gautam S Ghatnekar
- FirstString Research, Inc., 300 W. Coleman Blvd., Suite 203, Mount Pleasant, SC, USA.
| | - Elizabeth S Yeh
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, 173 Ashley Ave, BSB358, MSC509, Charleston, SC, 29425, USA.
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20
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Forster T, Rausch V, Zhang Y, Isayev O, Heilmann K, Schoensiegel F, Liu L, Nessling M, Richter K, Labsch S, Nwaeburu CC, Mattern J, Gladkich J, Giese N, Werner J, Schemmer P, Gross W, Gebhard MM, Gerhauser C, Schaefer M, Herr I. Sulforaphane counteracts aggressiveness of pancreatic cancer driven by dysregulated Cx43-mediated gap junctional intercellular communication. Oncotarget 2015; 5:1621-34. [PMID: 24742583 PMCID: PMC4039235 DOI: 10.18632/oncotarget.1764] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The extreme aggressiveness of pancreatic ductal adenocarcinoma (PDA) has been
associated with blocked gap junctional intercellular communication (GJIC) and the
presence of cancer stem cells (CSCs). We examined whether disturbed GJIC is
responsible for a CSC phenotype in established and primary cancer cells and patient
tissue of PDA using interdisciplinary methods based in physiology, cell and molecular
biology, histology and epigenetics. Flux of fluorescent dyes and gemcitabine through
gap junctions (GJs) was intact in less aggressive cells but not in highly malignant
cells with morphological dysfunctional GJs. Among several connexins, only Cx43 was
expressed on the cell surface of less aggressive and GJIC-competent cells, whereas
Cx43 surface expression was absent in highly malignant, E-cadherin-negative and
GJIC-incompetent cells. The levels of total Cx43 protein and Cx43 phosphorylated at
Ser368 and Ser279/282 were high in normal tissue but low to absent in malignant
tissue. si-RNA-mediated inhibition of Cx43 expression in GJIC-competent cells
prevented GJIC and induced colony formation and the expression of stem cell-related
factors. The bioactive substance sulforaphane enhanced Cx43 and E-cadherin levels,
inhibited the CSC markers c-Met and CD133, improved the functional morphology of GJs
and enhanced GJIC. Sulforaphane altered the phosphorylation of several kinases and
their substrates and inhibition of GSK3, JNK and PKC prevented sulforaphane-induced
CX43 expression. The sulforaphane-mediated expression of Cx43 was not correlated with
enhanced Cx43 RNA expression, acetylated histone binding and Cx43 promoter
de-methylation, suggesting that posttranslational phosphorylation is the dominant
regulatory mechanism. Together, the absence of Cx43 prevents GJIC and enhances
aggressiveness, whereas sulforaphane counteracts this process, and our findings
highlight dietary co-treatment as a viable treatment option for PDA.
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Affiliation(s)
- Tobias Forster
- General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
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21
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Ismail R, Rashid R, Andrabi K, Parray FQ, Besina S, Shah MA, Ul Hussain M. Pathological implications of Cx43 down-regulation in human colon cancer. Asian Pac J Cancer Prev 2015; 15:2987-91. [PMID: 24815435 DOI: 10.7314/apjcp.2014.15.7.2987] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Connexin 43 is an important gap junction protein in vertebrates and is known for its tumor suppressive properties. Cx43 is abundantly expressed in the human intestinal epithelial cells and muscularis mucosae. To explore the role of Cx43 in the genesis of human colon cancer, we performed the expression analysis of Cx43 in 80 cases of histopathologically confirmed and clinically diagnosed human colon cancer samples and adjacent control tissue and assessed correlations with clinicopathological variables. Western blotting using anti-Cx43 antibody indicated that the expression of Cx43 was significantly down regulated (75%) in the cancer samples as compared to the adjacent control samples. Moreover, immunohistochemical analysis of the tissue samples confirmed the down regulation of the Cx43 in the intestinal epithelial cells. Cx43 down regulation showed significant association (p<0.05) with the histological type and tumor invasion properties of the cancer. Our data demonstrated that loss of Cx43 may be an important event in colon carcinogenesis and tumor progression, providing significant insights about the tumor suppressive properties of the Cx43 and its potential as a diagnostic marker for colon cancer.
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Affiliation(s)
- Rehana Ismail
- Department of Biotechnology, University of Kashmir, Kashmir, India E-mail :
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22
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Smyth JW, Shaw RM. Autoregulation of connexin43 gap junction formation by internally translated isoforms. Cell Rep 2013; 5:611-8. [PMID: 24210816 DOI: 10.1016/j.celrep.2013.10.009] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/22/2013] [Accepted: 10/03/2013] [Indexed: 10/26/2022] Open
Abstract
During each heartbeat, intercellular electrical coupling via connexin43 (Cx43) gap junctions enables synchronous cardiac contraction. In failing hearts, impaired Cx43 trafficking reduces gap junction coupling, resulting in arrhythmias. Here we report that internal translation within Cx43 (GJA1) mRNA occurs, resulting in truncated isoforms that autoregulate Cx43 trafficking. We find that at least four truncated Cx43 isoforms occur in the human heart, with a 20 kDa isoform predominating. In-frame AUG codons within GJA1 mRNA are the translation initiation sites and their ablation arrests trafficking of full-length Cx43. The 20 kDa isoform is sufficient to rescue this trafficking defect in trans, suggesting it as a trafficking chaperone for Cx43. Limiting cap-dependent translation through inhibition of mTOR enhances truncated isoform expression, increasing Cx43 gap junction size. The results suggest that internal translation is a mechanism of membrane protein autoregulation and a potent target for therapies aimed at restoring normal electrical coupling in diseased hearts.
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Affiliation(s)
- James W Smyth
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA 94148, USA
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23
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Abstract
Pancreatic ductal adenocarcinoma is the 10th most common cancer and the fourth leading cause of cancer-related death in the United States. Despite great effort, the prognosis for patients with this disease remains dismal with a 5-year survival rate of just 4% to 6%. Although several important advances have improved our understanding of the underlying biology of pancreatic cancer, this knowledge has not translated into novel therapeutic approaches and effective systemic or targeted therapies. Pancreatic cancer is one of the malignancies most difficult to treat, with remarkable intrinsic resistance to both standard and targeted chemotherapy as well as ionizing radiation. Surgical intervention remains the only potentially curative approach. However, most patients present with inoperable and/or metastatic disease and are therefore excluded from surgery. Accordingly, new therapeutic options are desperately needed. In vivo models to study innovative and alternative treatment approaches are of major importance. A variety of genetically engineered mouse models of pancreatic cancer have been developed over the last decade. However, these models display different characteristics, and not all of them are suited for preclinical studies. In this review, we aim to review the mouse models available, their experimental use, their clinical relevance and limitations, and future directions.
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Affiliation(s)
- C. Benedikt Westphalen
- Department of Medicine, Division of Digestive and Liver Diseases, Columbia University Medical Center, New York, NY 10032, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA
| | - Kenneth P. Olive
- Department of Medicine, Division of Digestive and Liver Diseases, Columbia University Medical Center, New York, NY 10032, USA
- Department of Pathology, Columbia University Medical Center, New York, NY 10032, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA
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