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Lysikova DV, Vasileva VY, Chubinskiy-Nadezhdin VI, Morachevskaya EA, Sudarikova AV. Capsazepine activates amiloride-insensitive ENaC-like channels in human leukemia cells. Biochem Biophys Res Commun 2023; 687:149187. [PMID: 37944472 DOI: 10.1016/j.bbrc.2023.149187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023]
Abstract
Sodium influx carried out by ion channels is one of the main regulators of water-salt and volume balance in cells of blood origin. Previously, we described amiloride-insensitive ENaC-like channels in human myeloid leukemia K562 cells; the intracellular regulatory mechanisms of the channels are associated with actin cytoskeleton dynamics. Recently, an extracellular mechanism of ENaC-like channels activation in K562 cells by the action of serine protease trypsin has been revealed. The other extracellular pathways that modulate ENaC (epithelial Na+ channel) activity and sodium permeability in transformed blood cells are not yet fully investigated. Here, we study the action of capsazepine (CPZ), as δ-ENaC activator, on single channel activity in K562 cells in whole-cell patch clamp experiments. Addition of CPZ (2 μM) to the extracellular solution caused an activation of sodium channels with typical features; unitary conductance was 15.1 ± 0.8 pS. Amiloride derivative benzamil (50 μM) did not inhibit their activity. Unitary currents and conductance of CPZ-activated channels were higher in Na+-containing extracellular solution than in Li+, that is one of the main fingerprints of δ-ENaC. The results of RT-PCR analysis and immunofluorescence staining also confirmed the expression of δ-hENaC (as well as α-, β-, γ-ENaC) at the mRNA and protein level. These findings allow us to speculate that CPZ activates amiloride-insensitive ENaC-like channels that contain δ-ENaC in К562 cells. Our data reveal a novel extracellular mechanism for ENaC-like activation in human leukemia cells.
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Affiliation(s)
- Daria V Lysikova
- Institute of Cytology, Russian Academy of Sciences, 194064 Tikhoretsky Ave. 4, St. Petersburg, Russia
| | - Valeria Y Vasileva
- Institute of Cytology, Russian Academy of Sciences, 194064 Tikhoretsky Ave. 4, St. Petersburg, Russia
| | | | - Elena A Morachevskaya
- Institute of Cytology, Russian Academy of Sciences, 194064 Tikhoretsky Ave. 4, St. Petersburg, Russia
| | - Anastasia V Sudarikova
- Institute of Cytology, Russian Academy of Sciences, 194064 Tikhoretsky Ave. 4, St. Petersburg, Russia.
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2
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Zheng Q, Wang Y, Zhao R, Han P, Zhao J, Li L, Zhou X, Li P, Mo Y, Pan X, Luo W, Zhou X. Inactivation of epithelial sodium ion channel molecules serves as effective diagnostic biomarkers in clear cell renal cell carcinoma. Genes Genomics 2023; 45:855-866. [PMID: 37133722 DOI: 10.1007/s13258-023-01376-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 03/08/2023] [Indexed: 05/04/2023]
Abstract
BACKGROUND Non-voltage-gated sodium channel, also known as the epithelial sodium channel (ENaC), formed by heteromeric complexes consisting of SCNN1A, SCNN1B, and SCNN1G, is responsible for maintaining sodium ion and body fluid homeostasis in epithelial cells. However, no systematic study of SCNN1 family members has been conducted in renal clear cell carcinoma (ccRCC) to date. OBJECTIVE To investigate the abnormal expression of SCNN1 family in ccRCC and its potential correlation with clinical parameters. METHODS The transcription and protein expression levels of SCNN1 family members in ccRCC were analyzed based on the TCGA database, and were confirmed by quantitative RT-PCR and immunohistochemical staining assays, respectively. The area under curve (AUC) was used to evaluate the diagnostic value of SCNN1 family members for ccRCC patients. RESULTS The mRNA and protein expression of SCNN1 family members was significantly downregulated in ccRCC compared with normal kidney tissues, which might be due to DNA hypermethylation in the promoter region. It is worth noting that the AUC of SCNN1A, SCNN1B, and SCNN1G were 0.965, 0.979, and 0.988 based on the TCGA database (p < 0.0001), respectively. The diagnostic value was even higher when combing these three members together (AUC = 0.997, p < 0.0001). Intriguingly, the mRNA level of SCNN1A was significantly lower in females compared with males, while SCNN1B and SCNN1G were increased with the progression of ccRCC and remarkably associated with a worse outcome for patients. CONCLUSION The aberrantly decrease of SCNN1 family members might serve as valuable biomarkers for the diagnosis of ccRCC.
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Affiliation(s)
- Qian Zheng
- Life Science Institute, Guangxi Medical University, Nanning, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Guangxi Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Nanning, China
| | - Yifang Wang
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Guangxi Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Nanning, China
| | - Ran Zhao
- Life Science Institute, Guangxi Medical University, Nanning, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Guangxi Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Nanning, China
| | - Peipei Han
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Guangxi Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Nanning, China
| | - Jun Zhao
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Guangxi Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Nanning, China
| | - Limei Li
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Guangxi Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Nanning, China
| | - Xiaohui Zhou
- Life Science Institute, Guangxi Medical University, Nanning, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Guangxi Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Nanning, China
| | - Ping Li
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Guangxi Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Nanning, China
| | - Yingxi Mo
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Guangxi Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Nanning, China
| | - Xinli Pan
- Guangxi Key Laboratory of Marine Natural Products and Combinatorial Biosynthesis Chemistry, Guangxi Academy of Sciences, Nanning, China
| | - Wenqi Luo
- Department of Pathology, Affiliated Tumor Hospital of Guangxi Medical University, Guangxi Zhuang Autonomous Region, Nanning, China.
| | - Xiaoying Zhou
- Life Science Institute, Guangxi Medical University, Nanning, China.
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Guangxi Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Nanning, China.
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3
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Leslie TK, Brackenbury WJ. Sodium channels and the ionic microenvironment of breast tumours. J Physiol 2023; 601:1543-1553. [PMID: 36183245 PMCID: PMC10953337 DOI: 10.1113/jp282306] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/11/2022] [Indexed: 11/08/2022] Open
Abstract
Cancers of epithelial origin such as breast, prostate, cervical, gastric, colon and lung cancer account for a large proportion of deaths worldwide. Better treatment of metastasis, the main cause of cancer deaths, is therefore urgently required. Several of these tumours have been shown to have an abnormally high concentration of Na+ ([Na+ ]) and emerging evidence points to this accumulation being due to elevated intracellular [Na+ ]. This poses intriguing questions about the cellular mechanisms underlying Na+ dysregulation in cancer, and its pathophysiological significance. Elevated intracellular [Na+ ] may be due to alterations in activity of the Na+ /K+ -ATPase, and/or increased influx via Na+ channels and Na+ -linked transporters. Maintenance of the electrochemical Na+ gradient across the plasma membrane is vital to power many cellular processes that are highly active in cancer cells, including glucose and glutamine import. Na+ channels are also upregulated in cancer cells, which in turn promotes tumour growth and metastasis. For example, ENaC and ASICs are overexpressed in cancers, increasing invasion and proliferation. In addition, voltage-gated Na+ channels are also upregulated in a range of tumour types, where they promote metastatic cell behaviours via various mechanisms, including membrane potential depolarisation and altered pH regulation. Together, recent findings relating to elevated Na+ in the tumour microenvironment and how this may be regulated by several classes of Na+ channels provide a link between altered Na+ handling and poor clinical outcome. There are new opportunities to leverage this altered Na+ microenvironment for therapeutic benefit, as exemplified by several ongoing clinical trials.
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Affiliation(s)
- Theresa K. Leslie
- Department of BiologyUniversity of YorkHeslingtonYorkUK
- York Biomedical Research InstituteUniversity of YorkHeslingtonYorkUK
| | - William J. Brackenbury
- Department of BiologyUniversity of YorkHeslingtonYorkUK
- York Biomedical Research InstituteUniversity of YorkHeslingtonYorkUK
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4
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Johnston JG, Welch AK, Cain BD, Sayeski PP, Gumz ML, Wingo CS. Aldosterone: Renal Action and Physiological Effects. Compr Physiol 2023; 13:4409-4491. [PMID: 36994769 DOI: 10.1002/cphy.c190043] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Aldosterone exerts profound effects on renal and cardiovascular physiology. In the kidney, aldosterone acts to preserve electrolyte and acid-base balance in response to changes in dietary sodium (Na+ ) or potassium (K+ ) intake. These physiological actions, principally through activation of mineralocorticoid receptors (MRs), have important effects particularly in patients with renal and cardiovascular disease as demonstrated by multiple clinical trials. Multiple factors, be they genetic, humoral, dietary, or otherwise, can play a role in influencing the rate of aldosterone synthesis and secretion from the adrenal cortex. Normally, aldosterone secretion and action respond to dietary Na+ intake. In the kidney, the distal nephron and collecting duct are the main targets of aldosterone and MR action, which stimulates Na+ absorption in part via the epithelial Na+ channel (ENaC), the principal channel responsible for the fine-tuning of Na+ balance. Our understanding of the regulatory factors that allow aldosterone, via multiple signaling pathways, to function properly clearly implicates this hormone as central to many pathophysiological effects that become dysfunctional in disease states. Numerous pathologies that affect blood pressure (BP), electrolyte balance, and overall cardiovascular health are due to abnormal secretion of aldosterone, mutations in MR, ENaC, or effectors and modulators of their action. Study of the mechanisms of these pathologies has allowed researchers and clinicians to create novel dietary and pharmacological targets to improve human health. This article covers the regulation of aldosterone synthesis and secretion, receptors, effector molecules, and signaling pathways that modulate its action in the kidney. We also consider the role of aldosterone in disease and the benefit of mineralocorticoid antagonists. © 2023 American Physiological Society. Compr Physiol 13:4409-4491, 2023.
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Affiliation(s)
- Jermaine G Johnston
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Amanda K Welch
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Brian D Cain
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
| | - Peter P Sayeski
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
| | - Michelle L Gumz
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Charles S Wingo
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
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Capatina AL, Lagos D, Brackenbury WJ. Targeting Ion Channels for Cancer Treatment: Current Progress and Future Challenges. Rev Physiol Biochem Pharmacol 2020; 183:1-43. [PMID: 32865696 DOI: 10.1007/112_2020_46] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ion channels are key regulators of cancer cell pathophysiology. They contribute to a variety of processes such as maintenance of cellular osmolarity and membrane potential, motility (via interactions with the cytoskeleton), invasion, signal transduction, transcriptional activity and cell cycle progression, leading to tumour progression and metastasis. Ion channels thus represent promising targets for cancer therapy. Ion channels are attractive targets because many of them are expressed at the plasma membrane and a broad range of existing inhibitors are already in clinical use for other indications. However, many of the ion channels identified in cancer cells are also active in healthy normal cells, so there is a risk that certain blockers may have off-target effects on normal physiological function. This review describes recent research advances into ion channel inhibitors as anticancer therapeutics. A growing body of evidence suggests that a range of existing and novel Na+, K+, Ca2+ and Cl- channel inhibitors may be effective for suppressing cancer cell proliferation, migration and invasion, as well as enhancing apoptosis, leading to suppression of tumour growth and metastasis, either alone or in combination with standard-of-care therapies. The majority of evidence to date is based on preclinical in vitro and in vivo studies, although there are several examples of ion channel-targeting strategies now reaching early phase clinical trials. Given the strong links between ion channel function and regulation of tumour growth, metastasis and chemotherapy resistance, it is likely that further work in this area will facilitate the development of new therapeutic approaches which will reach the clinic in the future.
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Affiliation(s)
| | - Dimitris Lagos
- Hull York Medical School, York, UK
- York Biomedical Research Institute, University of York, York, UK
| | - William J Brackenbury
- Department of Biology, University of York, York, UK.
- York Biomedical Research Institute, University of York, York, UK.
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Leslie TK, James AD, Zaccagna F, Grist JT, Deen S, Kennerley A, Riemer F, Kaggie JD, Gallagher FA, Gilbert FJ, Brackenbury WJ. Sodium homeostasis in the tumour microenvironment. Biochim Biophys Acta Rev Cancer 2019; 1872:188304. [PMID: 31348974 PMCID: PMC7115894 DOI: 10.1016/j.bbcan.2019.07.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 12/17/2022]
Abstract
The concentration of sodium ions (Na+) is raised in solid tumours and can be measured at the cellular, tissue and patient levels. At the cellular level, the Na+ gradient across the membrane powers the transport of H+ ions and essential nutrients for normal activity. The maintenance of the Na+ gradient requires a large proportion of the cell's ATP. Na+ is a major contributor to the osmolarity of the tumour microenvironment, which affects cell volume and metabolism as well as immune function. Here, we review evidence indicating that Na+ handling is altered in tumours, explore our current understanding of the mechanisms that may underlie these alterations and consider the potential consequences for cancer progression. Dysregulated Na+ balance in tumours may open opportunities for new imaging biomarkers and re-purposing of drugs for treatment.
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Affiliation(s)
- Theresa K Leslie
- Department of Biology, University of York, Heslington, York YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK
| | - Andrew D James
- Department of Biology, University of York, Heslington, York YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK
| | - Fulvio Zaccagna
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - James T Grist
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Surrin Deen
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Aneurin Kennerley
- York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK; Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | - Frank Riemer
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Joshua D Kaggie
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Ferdia A Gallagher
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Fiona J Gilbert
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - William J Brackenbury
- Department of Biology, University of York, Heslington, York YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK.
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7
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Alvarez Argote J, Dasanu CA. ASXL1 mutations in myeloid neoplasms: pathogenetic considerations, impact on clinical outcomes and survival. Curr Med Res Opin 2018; 34:757-763. [PMID: 28027687 DOI: 10.1080/03007995.2016.1276896] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND ASXL1 gene mutations include nonsense, missense, and frameshift mutations. Although their clinical significance is still debated, they may play an important role in the pathogenesis of several hematologic malignancies. METHODS Herein, we offer a comprehensive review on ASXL1 mutations, and link them with survival and clinical outcomes in patients with various myeloid neoplasms. Most relevant publications were identified through searching the PubMed/Medline database for articles published from inception to February 2016. FINDINGS In acute myeloid leukemia (AML), ASXL1 mutations tend to correlate with older age and male gender, and affect predominantly patients with secondary AML. De novo AML patients with ASXL1 mutations had significantly lower complete remission rates after standard high-dose chemotherapy and shorter survival. In chronic myelomonocytic leukemia and low- or intermediate-risk myelodysplastic syndromes, frameshift and nonsense mutations correlated with shorter survival and a higher risk of leukemic transformation. Overall survival was also shorter in primary myelofibrosis in the presence of ASXL1 mutations. CONCLUSIONS Further research on the role of ASXL1 mutations and therapeutic implications in neoplastic myeloid disorders is stringently needed. Given the relatively high prevalence of ASXL1 mutations, larger studies involving patients affected by these mutations will be feasible in the near future.
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Affiliation(s)
| | - Constantin A Dasanu
- b Lucy Curci Cancer Center, Eisenhower Medical Center, Hematology Oncology , Rancho Mirage , CA , USA
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8
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Yang Y, Luo Z, Hao Y, Ba W, Wang R, Wang W, Ding X, Li C. mTOR-mediated Na +/Ca 2+ exchange affects cell proliferation and metastasis of melanoma cells. Biomed Pharmacother 2017; 92:744-749. [PMID: 28591687 DOI: 10.1016/j.biopha.2017.05.104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 05/19/2017] [Accepted: 05/22/2017] [Indexed: 10/19/2022] Open
Abstract
Melanoma is a common malignant tumor, which is associated with high mortality rate. The multiple-drug resistance of tumor cells often results in failure of chemotherapy. The aim of our study is to investigate the expression of Nav 1.6 in human melanoma cells and human epidermal melanocytes. Additionally, the effect of Na+channels on Ca+ current and mTOR activity in melanoma cells were also analyzed. The protein expression levels of Nav1.6 in human melanocyte PIG1, WM266 and WM115 cells were investigated by western blot. After treatment of Na+ channel inhibitor Tetroadotoxin (TTX) or mTOR inhibitor rapamycin (RAPA), the electrophysiological activity (Na+ current and Ca2+ current) in WM266 and WM115 cells was detected by patch clamp technique. The expression of mTORC1 phosphorylates S6 kinase (p-S6), cell invasion and migration, cell proliferation and cell apoptosis were also performed. Results shown that Nav 1.6 was overexpressed in WM266 and WM115 cells, and the inhibition of Na+ channel by TTX reduced Na+ current. Both TTX and RAPA suppressed Ca2+ current and the expression of p-S6, thus inducing Na+ channel which activates the mTOR-Ca2+ signaling pathway. Both TTX and RAPA suppressed cell invasion, migration and proliferation, and promoted cell apoptosis of WM266 cells. Thus, the Nav1.6 sodium channel promotes cell proliferation and invasion through mTOR-mediated Na+/Ca2+ exchange in melanoma. The observations will provide a new perspective for understanding the malignant biological behavior of melanoma cells, and potentially provide a new drug target.
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Affiliation(s)
- Yi Yang
- Department of Dermatology, The Chinese PLA General Hospital, China
| | | | - Yonghong Hao
- Department of Dermatology, The Chinese PLA General Hospital, China
| | - Wei Ba
- Department of Dermatology, The Chinese PLA General Hospital, China
| | - Rui Wang
- Department of Dermatology, The Chinese PLA General Hospital, China
| | - Wenjuan Wang
- Department of Dermatology, The Chinese PLA General Hospital, China
| | - Xiangyu Ding
- Department of Dermatology, The Chinese PLA General Hospital, China
| | - Chengxin Li
- Department of Dermatology, The Chinese PLA General Hospital, China.
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9
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Hanukoglu I, Boggula VR, Vaknine H, Sharma S, Kleyman T, Hanukoglu A. Expression of epithelial sodium channel (ENaC) and CFTR in the human epidermis and epidermal appendages. Histochem Cell Biol 2017; 147:733-748. [PMID: 28130590 DOI: 10.1007/s00418-016-1535-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2016] [Indexed: 02/07/2023]
Abstract
A major function of the skin is the regulation of body temperature by sweat secretions. Sweat glands secrete water and salt, especially NaCl. Excreted water evaporates, cooling the skin surface, and Na+ ions are reabsorbed by the epithelial sodium channels (ENaC). Mutations in ENaC subunit genes lead to a severe multi-system (systemic) form of pseudohypoaldosteronism (PHA) type I, characterized by salt loss from aldosterone target organs, including sweat glands in the skin. In this study, we mapped the sites of localization of ENaC in the human skin by confocal microscopy using polyclonal antibodies generated against human αENaC. Our results reveal that ENaC is expressed strongly in all epidermal layers except stratum corneum, and also in the sebaceous glands, eccrine glands, arrector pili smooth muscle cells, and intra-dermal adipocytes. In smooth muscle cells and adipocytes, ENaC is co-localized with F-actin. No expression of ENaC was detected in the dermis. CFTR is strongly expressed in sebaceous glands. In epidermal appendages noted, except the eccrine sweat glands, ENaC is mainly located in the cytoplasm. In the eccrine glands and ducts, ENaC and CFTR are located on the apical side of the membrane. This localization of ENaC is compatible with ENaC's role in salt reabsorption. PHA patients may develop folliculitis, miliaria rubra, and atopic dermatitis-like skin lesions, due to sweat gland duct occlusion and inflammation of eccrine glands as a result of salt accumulation.
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Affiliation(s)
- Israel Hanukoglu
- Laboratory of Cell Biology, Ariel University, Ariel, 40700, Israel.
| | - Vijay R Boggula
- Laboratory of Cell Biology, Ariel University, Ariel, 40700, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Hananya Vaknine
- Division of Pathology, E. Wolfson Medical Center, Holon, Israel
| | - Sachin Sharma
- Laboratory of Cell Biology, Ariel University, Ariel, 40700, Israel
| | - Thomas Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Aaron Hanukoglu
- Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.,Division of Pediatric Endocrinology, E. Wolfson Medical Center, Holon, Israel
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10
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Liu C, Zhu LL, Xu SG, Ji HL, Li XM. ENaC/DEG in Tumor Development and Progression. J Cancer 2016; 7:1888-1891. [PMID: 27698929 PMCID: PMC5039373 DOI: 10.7150/jca.15693] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/29/2016] [Indexed: 11/05/2022] Open
Abstract
The epithelial Na+ channel/degenerin (ENaC/DEG) superfamily, including the acid-sensing ion channels (ASICs), is characterized by a high degree of similarity in structure but highly diverse in physiological functions. These ion channels have been shown to be important in several physiological functions of normal epithelial cells, including salt homeostasis, fluid transportation and cell mobility. There is increasing evidence suggesting that ENaC/DEG channels are critically engaged in cancer cell biology, such as proliferation, migration, invasion and apoptosis, playing a role in tumor development and progression. In this review, we will discuss recent studies showing the role of ENaC and ASIC channels in epithelial cells and its relationship to the oncogenesis.
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Affiliation(s)
- Cui Liu
- School of Nursing, Xinxiang Medical University, Xinxiang 453003, Henan Province, P. R. China
| | - Li-Li Zhu
- School of Nursing, Xinxiang Medical University, Xinxiang 453003, Henan Province, P. R. China
| | - Si-Guang Xu
- Institute of Lung and Molecular Therapy, Xinxiang Medical University, Xinxiang 453003, Henan Province, P. R. China
| | - Hong-Long Ji
- Institute of Lung and Molecular Therapy, Xinxiang Medical University, Xinxiang 453003, Henan Province, P. R. China
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas, USA
- Texas Lung Injury Institute, University of Texas Health Science Center at Tyler, Tyler, Texas, USA
| | - Xiu-Min Li
- Center for Cancer Research, Xinxiang Medical University, Xinxiang 453003, Henan Province, P. R. China
- Department Gastroenterology, the Third Affiliated Hospital of Xinxiang Medical University, Henan Province, P. R. China
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11
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Potential Roles of Amiloride-Sensitive Sodium Channels in Cancer Development. BIOMED RESEARCH INTERNATIONAL 2016; 2016:2190216. [PMID: 27403419 PMCID: PMC4926023 DOI: 10.1155/2016/2190216] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/18/2016] [Accepted: 05/23/2016] [Indexed: 12/15/2022]
Abstract
The ENaC/degenerin ion channel superfamily includes the amiloride-sensitive epithelial sodium channel (ENaC) and acid sensitive ionic channel (ASIC). ENaC is a multimeric ion channel formed by heteromultimeric membrane glycoproteins, which participate in a multitude of biological processes by mediating the transport of sodium (Na+) across epithelial tissues such as the kidney, lungs, bladder, and gut. Aberrant ENaC functions contribute to several human disease states including pseudohypoaldosteronism, Liddle syndrome, cystic fibrosis, and salt-sensitive hypertension. Increasing evidence suggests that ion channels not only regulate ion homeostasis and electric signaling in excitable cells but also play important roles in cancer cell behaviors such as proliferation, apoptosis, invasion, and migration. Indeed, ENaCs/ASICs had been reported to be associated with cancer characteristics. Given their cell surface localization and pharmacology, pharmacological strategies to target ENaC/ASIC family members may be promising cancer therapeutics.
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12
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Ji HL, Zhao RZ, Chen ZX, Shetty S, Idell S, Matalon S. δ ENaC: a novel divergent amiloride-inhibitable sodium channel. Am J Physiol Lung Cell Mol Physiol 2012; 303:L1013-26. [PMID: 22983350 DOI: 10.1152/ajplung.00206.2012] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The fourth subunit of the epithelial sodium channel, termed delta subunit (δ ENaC), was cloned in human and monkey. Increasing evidence shows that this unique subunit and its splice variants exhibit biophysical and pharmacological properties that are divergent from those of α ENaC channels. The widespread distribution of epithelial sodium channels in both epithelial and nonepithelial tissues implies a range of physiological functions. The altered expression of SCNN1D is associated with numerous pathological conditions. Genetic studies link SCNN1D deficiency with rare genetic diseases with developmental and functional disorders in the brain, heart, and respiratory systems. Here, we review the progress of research on δ ENaC in genomics, biophysics, proteomics, physiology, pharmacology, and clinical medicine.
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Affiliation(s)
- Hong-Long Ji
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas, USA.
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13
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Nguyen TH, Weber W, Havari E, Connors T, Bagley RG, McLaren R, Nambiar PR, Madden SL, Teicher BA, Roberts B, Kaplan J, Shankara S. Expression of TMPRSS4 in non-small cell lung cancer and its modulation by hypoxia. Int J Oncol 2012; 41:829-38. [PMID: 22692880 PMCID: PMC3582903 DOI: 10.3892/ijo.2012.1513] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 02/02/2012] [Indexed: 01/20/2023] Open
Abstract
Overexpression of TMPRSS4, a cell surface-associated transmembrane serine protease, has been reported in pancreatic, colorectal and thyroid cancers, and has been implicated in tumor cell migration and metastasis. Few reports have investigated both TMPRSS4 gene expression levels and the protein products. In this study, quantitative RT-PCR and protein staining were used to assess TMPRSS4 expression in primary non-small cell lung carcinoma (NSCLC) tissues and in lung tumor cell lines. At the transcriptional level, TMPRSS4 message was significantly elevated in the majority of human squamous cell and adenocarcinomas compared with normal lung tissues. Staining of over 100 NSCLC primary tumor and normal specimens with rabbit polyclonal anti-TMPRSS4 antibodies confirmed expression at the protein level in both squamous cell and adenocarcinomas with little or no staining in normal lung tissues. Human lung tumor cell lines expressed varying levels of TMPRSS4 mRNA in vitro. Interestingly, tumor cell lines with high levels of TMPRSS4 mRNA failed to show detectable TMPRSS4 protein by either immunoblotting or flow cytometry. However, protein levels were increased under hypoxic culture conditions suggesting that hypoxia within the tumor microenvironment may upregulate TMPRSS4 protein expression in vivo. This was supported by the observation of TMPRSS4 protein in xenograft tumors derived from the cell lines. In addition, staining of human squamous cell carcinoma samples for carbonic anhydrase IX (CAIX), a hypoxia marker, showed TMPRSS4 positive cells adjacent to CAIX positive cells. Overall, these results indicate that the cancer-associated TMPRSS4 protein is overexpressed in NSCLC and may represent a potential therapeutic target.
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Abstract
The epithelial Na(+) channel (ENaC) and acid-sensitive ion channel (ASIC) branches of the ENaC/degenerin superfamily of cation channels have drawn increasing attention as potential therapeutic targets in a variety of diseases and conditions. Originally thought to be solely expressed in fluid absorptive epithelia and in neurons, it has become apparent that members of this family exhibit nearly ubiquitous expression. Therapeutic opportunities range from hypertension, due to the role of ENaC in maintaining whole body salt and water homeostasis, to anxiety disorders and pain associated with ASIC activity. As a physiologist intrigued by the fundamental mechanics of salt and water transport, it was natural that Dale Benos, to whom this series of reviews is dedicated, should have been at the forefront of research into the amiloride-sensitive sodium channel. The cloning of ENaC and subsequently the ASIC channels has revealed a far wider role for this channel family than was previously imagined. In this review, we will discuss the known and potential roles of ENaC and ASIC subunits in the wide variety of pathologies in which these channels have been implicated. Some of these, such as the role of ENaC in Liddle's syndrome are well established, others less so; however, all are related in that the fundamental defect is due to inappropriate channel activity.
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Affiliation(s)
- Yawar J Qadri
- Department of Physiology and Biophysics, University of Alabama at Birmingham, AL 35294, USA
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15
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Zhu J, Jiang Z, Gao F, Hu X, Zhou L, Chen J, Luo H, Sun J, Wu S, Han Y, Yin G, Chen M, Han Z, Li X, Huang Y, Zhang W, Zhou F, Chen T, Fa P, Wang Y, Sun L, Leng H, Sun F, Liu Y, Ye M, Yang H, Cai Z, Gui Y, Zhang X. A systematic analysis on DNA methylation and the expression of both mRNA and microRNA in bladder cancer. PLoS One 2011; 6:e28223. [PMID: 22140553 PMCID: PMC3227661 DOI: 10.1371/journal.pone.0028223] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 11/03/2011] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND DNA methylation aberration and microRNA (miRNA) deregulation have been observed in many types of cancers. A systematic study of methylome and transcriptome in bladder urothelial carcinoma has never been reported. METHODOLOGY/PRINCIPAL FINDINGS The DNA methylation was profiled by modified methylation-specific digital karyotyping (MMSDK) and the expression of mRNAs and miRNAs was analyzed by digital gene expression (DGE) sequencing in tumors and matched normal adjacent tissues obtained from 9 bladder urothelial carcinoma patients. We found that a set of significantly enriched pathways disrupted in bladder urothelial carcinoma primarily related to "neurogenesis" and "cell differentiation" by integrated analysis of -omics data. Furthermore, we identified an intriguing collection of cancer-related genes that were deregulated at the levels of DNA methylation and mRNA expression, and we validated several of these genes (HIC1, SLIT2, RASAL1, and KRT17) by Bisulfite Sequencing PCR and Reverse Transcription qPCR in a panel of 33 bladder cancer samples. CONCLUSIONS/SIGNIFICANCE We characterized the profiles between methylome and transcriptome in bladder urothelial carcinoma, identified a set of significantly enriched key pathways, and screened four aberrantly methylated and expressed genes. Conclusively, our findings shed light on a new avenue for basic bladder cancer research.
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Affiliation(s)
- Jialou Zhu
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
- College of Life Science, Wuhan University, Wuhan, China
| | - Zhimao Jiang
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
| | - Fei Gao
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Xueda Hu
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
- Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Liang Zhou
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
| | - Jiahao Chen
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Huijuan Luo
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Jihua Sun
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Song Wu
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
| | - Yonghua Han
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
| | | | - Maoshan Chen
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Zujing Han
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Xianxin Li
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
| | - Yi Huang
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
| | - Weixing Zhang
- Department of Urology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Fangjian Zhou
- Department of Urology, Sun Yat-Sen University Cancer Center, Guangzhou, China
| | - Tong Chen
- Department of Urology, Shenzhen People's Hospital, Shenzhen, China
| | - Pingping Fa
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
| | - Yong Wang
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
| | - Liang Sun
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
| | - Huimin Leng
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
| | - Fenghao Sun
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
- Shantou University Medical College, Shantou, China
| | - Yuchen Liu
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
- Department of Urology, Shenzhen People's Hospital, Shenzhen, China
| | - Mingzhi Ye
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Huanming Yang
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Zhiming Cai
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
- Department of Urology, The Second People's Hospital of Shenzhen, Shenzhen, China
| | - Yaoting Gui
- Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, China
- * E-mail: (XZ); (YG)
| | - Xiuqing Zhang
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
- * E-mail: (XZ); (YG)
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Blackiston D, Adams DS, Lemire JM, Lobikin M, Levin M. Transmembrane potential of GlyCl-expressing instructor cells induces a neoplastic-like conversion of melanocytes via a serotonergic pathway. Dis Model Mech 2011; 4:67-85. [PMID: 20959630 PMCID: PMC3008964 DOI: 10.1242/dmm.005561] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 08/23/2010] [Indexed: 12/14/2022] Open
Abstract
Understanding the mechanisms that coordinate stem cell behavior within the host is a high priority for developmental biology, regenerative medicine and oncology. Endogenous ion currents and voltage gradients function alongside biochemical cues during pattern formation and tumor suppression, but it is not known whether bioelectrical signals are involved in the control of stem cell progeny in vivo. We studied Xenopus laevis neural crest, an embryonic stem cell population that gives rise to many cell types, including melanocytes, and contributes to the morphogenesis of the face, heart and other complex structures. To investigate how depolarization of transmembrane potential of cells in the neural crest's environment influences its function in vivo, we manipulated the activity of the native glycine receptor chloride channel (GlyCl). Molecular-genetic depolarization of a sparse, widely distributed set of GlyCl-expressing cells non-cell-autonomously induces a neoplastic-like phenotype in melanocytes: they overproliferate, acquire an arborized cell shape and migrate inappropriately, colonizing numerous tissues in a metalloprotease-dependent fashion. A similar effect was observed in human melanocytes in culture. Depolarization of GlyCl-expressing cells induces these drastic changes in melanocyte behavior via a serotonin-transporter-dependent increase of extracellular serotonin (5-HT). These data reveal GlyCl as a molecular marker of a sparse and heretofore unknown cell population with the ability to specifically instruct neural crest derivatives, suggest transmembrane potential as a tractable signaling modality by which somatic cells can control stem cell behavior at considerable distance, identify a new biophysical aspect of the environment that confers a neoplastic-like phenotype upon stem cell progeny, reveal a pre-neural role for serotonin and its transporter, and suggest a novel strategy for manipulating stem cell behavior.
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Affiliation(s)
- Douglas Blackiston
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
- Department of Regenerative and Developmental Biology, Forsyth Institute, Boston, MA 02115, USA
| | - Dany S. Adams
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
| | - Joan M. Lemire
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
| | - Maria Lobikin
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
| | - Michael Levin
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
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17
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Yamamura H, Ugawa S, Ueda T, Nagao M, Joh T, Shimada S. Epithelial Na+ channel delta subunit is an acid sensor in the human oesophagus. Eur J Pharmacol 2008; 600:32-6. [PMID: 18951889 DOI: 10.1016/j.ejphar.2008.10.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 10/09/2008] [Indexed: 01/11/2023]
Abstract
Gastro-oesophageal reflux disease is caused by the reflux of gastric contents into the oesophagus, and thus the oesophageal lumen is damaged by gastric acid. The acid sensor involved in oesophageal epithelial defense is still unclear. Recently, we described that the epithelial Na(+) channel delta subunit (ENaCdelta) is a candidate molecule for a pH sensor in the human brain. Here, using reverse transcription-polymerase chain reaction and in situ hybridization methods, we showed that the proton-sensitive ENaCdelta was strongly expressed in the epithelial layer of the human oesophagus, representative peripheral tissue that can be exposed to an acidic environment. Other ENaC subunits (alpha, beta, and gamma) were also localized there. Based on the expression pattern, human oesophageal ENaC complex was mimicked in the Xenopus oocyte expression system and the response to acidic pH was recorded using a two-electrode voltage-clamp technique. The human oesophageal-mimicking ENaCdeltabetagammaalpha complex generated an amiloride-sensitive inward current at the holding potential of -60 mV. The ENaCdeltabetagammaalpha current was significantly activated by acidic pH (pH 4.0), approximately equal to the luminal value when gastric acid refluxes into the oesophagus. In conclusion, ENaCdelta is a candidate molecule for pH sensing in the gastrointestinal system in humans, providing a novel therapeutic target for gastro-oesophageal reflux disease.
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Affiliation(s)
- Hisao Yamamura
- Department of Molecular Morphology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan.
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Yamamura H, Ugawa S, Ueda T, Morita A, Shimada S. TRPM8 activation suppresses cellular viability in human melanoma. Am J Physiol Cell Physiol 2008; 295:C296-301. [DOI: 10.1152/ajpcell.00499.2007] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The transient receptor potential melastatin subfamily (TRPM), which is a mammalian homologue of cell death-regulated genes in Caenorhabditis elegans and Drosophila, has potential roles in the process of the cell cycle and regulation of Ca2+signaling. Among this subfamily, TRPM8 (also known as Trp-p8) is a Ca2+-permeable channel that was originally identified as a prostate-specific gene upregulated in tumors. Here we showed that the TRPM8 channel was expressed in human melanoma G-361 cells, and activation of the channel produced sustainable Ca2+influx. The application of menthol, an agonist for TRPM8 channel, elevated cytosolic Ca2+concentration in a concentration-dependent manner with an EC50value of 286 μM in melanoma cells. Menthol-induced responses were significantly abolished by the removal of external Ca2+. Moreover, inward currents at a holding potential of −60 mV in melanoma cells were markedly potentiated by the addition of 300 μM menthol. The most striking finding was that the viability of melanoma cells was dose-dependently depressed in the presence of menthol. These results reveal that a functional TRPM8 protein is expressed in human melanoma cells to involve the mechanism underlying tumor progression via the Ca2+handling pathway, providing us with a novel target of drug development for malignant melanoma.
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Epithelial Na+ channel delta subunit mediates acid-induced ATP release in the human skin. Biochem Biophys Res Commun 2008; 373:155-8. [PMID: 18555798 DOI: 10.1016/j.bbrc.2008.06.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 06/03/2008] [Indexed: 11/22/2022]
Abstract
The amiloride-sensitive epithelial Na(+) channel (ENaC) regulates Na(+) homeostasis in cells and across epithelia. Although we described that ENaCdelta is a candidate molecule for a pH sensor in the human brain, the physiological and pathological roles of ENaCdelta in non-neuronal tissues are still unknown. Here we show a novel physiological function of ENaCdelta in peripheral tissues in humans. Expression analyses at the level of mRNA clearly revealed that ENaCdelta was abundantly expressed in human epidermis and keratinocytes. In addition, ENaCdelta protein was detected in there. In cultured keratinocytes, acidic stress (pH 5.0) evoked ATP release, which was significantly reduced in the presence of 100 microM amiloride or 10 microM benzamil. In conclusion, ENaCdelta may be involved in the mechanism underlying pH sensing followed by the regulation of cell viability in the human skin.
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