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Piga M, Varga Z, Feher A, Papp F, Korpos E, Bangera KC, Frlan R, Ilaš J, Dernovšek J, Tomašič T, Zidar N. Identification of a Novel Structural Class of H V1 Inhibitors by Structure-Based Virtual Screening. J Chem Inf Model 2024; 64:4850-4862. [PMID: 38850237 PMCID: PMC11200261 DOI: 10.1021/acs.jcim.4c00240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 06/10/2024]
Abstract
The human voltage-gated proton channel, hHV1, is highly expressed in various cell types including macrophages, B lymphocytes, microglia, sperm cells and also in various cancer cells. Overexpression of HV1 has been shown to promote tumor formation by highly metastatic cancer cells, and has been associated with neuroinflammatory diseases, immune response disorders and infertility, suggesting a potential use of hHV1 inhibitors in numerous therapeutic areas. To identify compounds targeting this channel, we performed a structure-based virtual screening on an open structure of the human HV1 channel. Twenty selected virtual screening hits were tested on Chinese hamster ovary (CHO) cells transiently expressing hHV1, with compound 13 showing strong block of the proton current with an IC50 value of 8.5 μM. Biological evaluation of twenty-three additional analogs of 13 led to the discovery of six other compounds that blocked the proton current by more than 50% at 50 μM concentration. This allowed for an investigation of structure-activity relationships. The antiproliferative activity of the selected promising hHV1 inhibitors was investigated in the cell lines MDA-MB-231 and THP-1, where compound 13 inhibited growth with an IC50 value of 9.0 and 8.1 μM, respectively. The identification of a new structural class of HV1 inhibitors contributes to our understanding of the structural requirements for inhibition of this ion channel and opens up the possibility of investigating the role of HV1 inhibitors in various pathological conditions and in cancer therapy.
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Affiliation(s)
- Martina Piga
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
| | - Zoltan Varga
- Faculty
of Medicine, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Adam Feher
- Faculty
of Medicine, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Ferenc Papp
- Faculty
of Medicine, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Eva Korpos
- Faculty
of Medicine, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
- HUN-REN−UD
Cell Biology and Signaling Research Group, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Kavya C. Bangera
- Faculty
of Medicine, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Rok Frlan
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
| | - Janez Ilaš
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
| | - Jaka Dernovšek
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
| | - Tihomir Tomašič
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
| | - Nace Zidar
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
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2
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Kawanabe A, Takeshita K, Takata M, Fujiwara Y. ATP modulates the activity of the voltage-gated proton channel through direct binding interaction. J Physiol 2023; 601:4073-4089. [PMID: 37555355 DOI: 10.1113/jp284175] [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: 11/29/2022] [Accepted: 07/27/2023] [Indexed: 08/10/2023] Open
Abstract
ATP is an important molecule implicated in diverse biochemical processes, including the modulation of ion channel and transporter activity. The voltage-gated proton channel (Hv1) controls proton flow through the transmembrane pathway in response to membrane potential, and various molecules regulate its activity. Although it is believed that ATP is not essential for Hv1 activity, a report has indicated that cytosolic ATP may modulate Hv1. However, the detailed molecular mechanism underlying the effect of ATP on Hv1 is unknown, and whether ATP is involved in the physiological regulation of Hv1 activity remains unclear. Here, we report that cytosolic ATP is required to maintain Hv1 activity. To gain insight into the underlying mechanism, we analysed the effects of ATP on the mouse Hv1 channel (mHv1) using electrophysiological and microscale thermophoresis (MST) methods. Intracellular ATP accelerated the activation kinetics of mHv1, thereby increasing the amplitude of the proton current within the physiological concentration range. The increase in proton current was reproduced with a non-hydrolysable ATP analogue, indicating that ATP directly influences Hv1 activity without an enzymatic reaction. The direct molecular interaction between the purified mHv1 protein and ATP was analysed and demonstrated through MST. In addition, ATP facilitation was observed for the endogenous proton current flowing through Hv1 in the physiological concentration range of ATP. These results suggest that ATP influences Hv1 activity via direct molecular interactions and is required for the physiological function of Hv1. KEY POINTS: We found that ATP is required to maintain the activity of voltage-gated proton channels (Hv1) and investigated the underlying molecular mechanism. Application of intracellular ATP increased the amplitude of the proton current flowing through Hv1, accompanied by an acceleration of activation kinetics. The direct interaction between purified Hv1 protein and ATP was quantitatively analysed using microscale thermophoresis. ATP enhanced endogenous proton currents in breast cancer cell lines. These results suggest that ATP influences Hv1 activity via direct molecular interactions and that its functional characteristics are required for the physiological activity of Hv1.
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Affiliation(s)
- Akira Kawanabe
- Laboratory of Molecular Physiology & Biophysics, Faculty of Medicine, Kagawa University, Miki-cho, Kagawa, Japan
| | | | - Maki Takata
- Laboratory of Molecular Physiology & Biophysics, Faculty of Medicine, Kagawa University, Miki-cho, Kagawa, Japan
| | - Yuichiro Fujiwara
- Laboratory of Molecular Physiology & Biophysics, Faculty of Medicine, Kagawa University, Miki-cho, Kagawa, Japan
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3
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Shen Y, Luo Y, Liao P, Zuo Y, Jiang R. Role of the Voltage-Gated Proton Channel Hv1 in Nervous Systems. Neurosci Bull 2023; 39:1157-1172. [PMID: 37029856 PMCID: PMC10313628 DOI: 10.1007/s12264-023-01053-6] [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: 10/12/2022] [Accepted: 02/20/2023] [Indexed: 04/09/2023] Open
Abstract
Hv1 is the only voltage-gated proton-selective channel in mammalian cells. It contains a conserved voltage-sensor domain, shared by a large class of voltage-gated ion channels, but lacks a pore domain. Its primary role is to extrude protons from the cytoplasm upon pH reduction and membrane depolarization. The best-known function of Hv1 is the regulation of cytosolic pH and the nicotinamide adenine dinucleotide phosphate oxidase-dependent production of reactive oxygen species. Accumulating evidence indicates that Hv1 is expressed in nervous systems, in addition to immune cells and others. Here, we summarize the molecular properties, distribution, and physiological functions of Hv1 in the peripheral and central nervous systems. We describe the recently discovered functions of Hv1 in various neurological diseases, including brain or spinal cord injury, ischemic stroke, demyelinating diseases, and pain. We also summarize the current advances in the discovery and application of Hv1-targeted small molecules in neurological diseases. Finally, we discuss the current limitations of our understanding of Hv1 and suggest future research directions.
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Affiliation(s)
- Yu Shen
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
| | - Yuncheng Luo
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
| | - Ping Liao
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
| | - Yunxia Zuo
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
| | - Ruotian Jiang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China.
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China.
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Chaves G, Jardin C, Derst C, Musset B. Voltage-Gated Proton Channels in the Tree of Life. Biomolecules 2023; 13:1035. [PMID: 37509071 PMCID: PMC10377628 DOI: 10.3390/biom13071035] [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: 05/14/2023] [Revised: 06/14/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
With a single gene encoding HV1 channel, proton channel diversity is particularly low in mammals compared to other members of the superfamily of voltage-gated ion channels. Nonetheless, mammalian HV1 channels are expressed in many different tissues and cell types where they exert various functions. In the first part of this review, we regard novel aspects of the functional expression of HV1 channels in mammals by differentially comparing their involvement in (1) close conjunction with the NADPH oxidase complex responsible for the respiratory burst of phagocytes, and (2) in respiratory burst independent functions such as pH homeostasis or acid extrusion. In the second part, we dissect expression of HV channels within the eukaryotic tree of life, revealing the immense diversity of the channel in other phylae, such as mollusks or dinoflagellates, where several genes encoding HV channels can be found within a single species. In the last part, a comprehensive overview of the biophysical properties of a set of twenty different HV channels characterized electrophysiologically, from Mammalia to unicellular protists, is given.
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Affiliation(s)
- Gustavo Chaves
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
| | - Christophe Jardin
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
| | - Christian Derst
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
| | - Boris Musset
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
- Center of Physiology, Pathophysiology and Biophysics, The Salzburg Location, Paracelsus Medical University, 5020 Salzburg, Austria
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5
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El Chemaly A, Jaquet V, Cambet Y, Caillon A, Cherpin O, Balafa A, Krause KH, Demaurex N. Discovery and validation of new Hv1 proton channel inhibitors with onco-therapeutic potential. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119415. [PMID: 36640925 DOI: 10.1016/j.bbamcr.2022.119415] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 01/13/2023]
Abstract
The voltage-gated hydrogen channel Hv1 encoded in humans by the HVCN1 gene is a highly selective proton channel that allows large fluxes of protons across biological membranes. Hv1 form functional dimers of four transmembrane spanning proteins resembling the voltage sensing domain of potassium channels. Each subunit is highly selective for protons and is controlled by changes in the transmembrane voltage and pH gradient. Hv1 is most expressed in phagocytic cells where it sustains NADPH oxidase-dependent bactericidal function and was reported to facilitate antibody production by B cells and to promote the maturation and motility of spermatocytes. Hv1 contributes to neuroinflammation following brain damage and favors cancer progression possibly by extruding protons generated during aerobic glycolysis of cancer cells. Lack of specific Hv1 inhibitors has hampered translation of this knowledge to treat immune, fertility, or malignancy diseases. In this study, we show that the genetic deletion of Hv1 delays tumor development in a mouse model of granulocytic sarcoma and report the discovery and characterization of two novel bioavailable inhibitors of Hv1 channels that we validate by orthogonal assays and electrophysiological recordings.
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Affiliation(s)
- Antoun El Chemaly
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva 1211, Switzerland
| | - Vincent Jaquet
- Department of Pathology and Immunology, University of Geneva, Geneva 1211, Switzerland; READs unit, University of Geneva, Geneva 1211, Switzerland
| | - Yves Cambet
- READs unit, University of Geneva, Geneva 1211, Switzerland
| | - Aurélie Caillon
- Department of Pathology and Immunology, University of Geneva, Geneva 1211, Switzerland
| | - Ophélie Cherpin
- Department of Pathology and Immunology, University of Geneva, Geneva 1211, Switzerland
| | - Alexia Balafa
- Department of Pathology and Immunology, University of Geneva, Geneva 1211, Switzerland
| | - Karl-Heinz Krause
- Department of Pathology and Immunology, University of Geneva, Geneva 1211, Switzerland
| | - Nicolas Demaurex
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva 1211, Switzerland.
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6
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Alvear-Arias JJ, Pena-Pichicoi A, Carrillo C, Fernandez M, Gonzalez T, Garate JA, Gonzalez C. Role of voltage-gated proton channel (Hv1) in cancer biology. Front Pharmacol 2023; 14:1175702. [PMID: 37153807 PMCID: PMC10157179 DOI: 10.3389/fphar.2023.1175702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/11/2023] [Indexed: 05/10/2023] Open
Abstract
The acid-base characteristics of tumor cells and the other elements that compose the tumor microenvironment have been topics of scientific interest in oncological research. There is much evidence confirming that pH conditions are maintained by changes in the patterns of expression of certain proton transporters. In the past decade, the voltage-gated proton channel (Hv1) has been added to this list and is increasingly being recognized as a target with onco-therapeutic potential. The Hv1 channel is key to proton extrusion for maintaining a balanced cytosolic pH. This protein-channel is expressed in a myriad of tissues and cell lineages whose functions vary from producing bioluminescence in dinoflagellates to alkalizing spermatozoa cytoplasm for reproduction, and regulating the respiratory burst for immune system response. It is no wonder that in acidic environments such as the tumor microenvironment, an exacerbated expression and function of this channel has been reported. Indeed, multiple studies have revealed a strong relationship between pH balance, cancer development, and the overexpression of the Hv1 channel, being proposed as a marker for malignancy in cancer. In this review, we present data that supports the idea that the Hv1 channel plays a significant role in cancer by maintaining pH conditions that favor the development of malignancy features in solid tumor models. With the antecedents presented in this bibliographic report, we want to strengthen the idea that the Hv1 proton channel is an excellent therapeutic strategy to counter the development of solid tumors.
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Affiliation(s)
- Juan J. Alvear-Arias
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Antonio Pena-Pichicoi
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Christian Carrillo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Miguel Fernandez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Tania Gonzalez
- National Center for Minimally Invasive Surgery, La Habana, Cuba
| | - Jose A. Garate
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia y Vida, Santiago, Chile
| | - Carlos Gonzalez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL, United States
- *Correspondence: Carlos Gonzalez,
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7
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Zhao R, Lopez B, Schwingshackl A, Goldstein SA. Protection from acute lung injury by a peptide designed to inhibit the voltage-gated proton channel. iScience 2022; 26:105901. [PMID: 36660473 PMCID: PMC9843441 DOI: 10.1016/j.isci.2022.105901] [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: 02/27/2022] [Revised: 12/06/2022] [Accepted: 12/27/2022] [Indexed: 12/30/2022] Open
Abstract
There are no targeted medical therapies for Acute Lung Injury (ALI) or its most severe form acute respiratory distress syndrome (ARDS). Infections are the most common cause of ALI/ARDS and these disorders present clinically with alveolar inflammation and barrier dysfunction due to the influx of neutrophils and inflammatory mediator secretion. We designed the C6 peptide to inhibit voltage-gated proton channels (Hv1) and demonstrated that it suppressed the release of reactive oxygen species (ROS) and proteases from neutrophils in vitro. We now show that intravenous C6 counteracts bacterial lipopolysaccharide (LPS)-induced ALI in mice, and suppresses the accumulation of neutrophils, ROS, and proinflammatory cytokines in bronchoalveolar lavage fluid. Confirming the salutary effects of C6 are via Hv1, genetic deletion of the channel similarly protects mice from LPS-induced ALI. This report reveals that Hv1 is a key regulator of ALI, that Hv1 is a druggable target, and that C6 is a viable agent to treat ALI/ARDS.
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Affiliation(s)
- Ruiming Zhao
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Benjamin Lopez
- Department of Pediatrics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Andreas Schwingshackl
- Department of Pediatrics, University of California, Los Angeles, Los Angeles, CA 90095, USA,Corresponding author
| | - Steve A.N. Goldstein
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA,Corresponding author
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8
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Wu X, Zhang L, Hong L. The role of Phe150 in human voltage-gated proton channel. iScience 2022; 25:105420. [PMID: 36388967 PMCID: PMC9646954 DOI: 10.1016/j.isci.2022.105420] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/15/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022] Open
Abstract
The voltage-gated proton channel Hv1 is a member of voltage-gated ion channels containing voltage-sensing domains (VSDs). The VSDs are made of four membrane-spanning segments (S1 through S4), and their function is to detect changes in membrane potential in the cells. A highly conserved phenylalanine 150 (F150) is located in the S2 segment of human voltage-gated proton channels. We previously discovered that the F150 is a binding site for the open channel blocker 2GBI. Here, we show that the Hv1 VSD voltage-dependent activation requires a hydrophobic group at position F150. We perform double-mutant cycle analysis to probe interactions between F150 and positively charged arginines in the S4 segment of the channel. Our results indicate that F150 interacts with two arginines (R2 and R3) in the S4 segment and catalyzes the transfer of the S4 arginines in the process of voltage-dependent activation. Hydrophobicity of F150 is crucial for human Hv1 channel voltage-dependent activation F150 interacts with R2 to stabilize the closed state of the Hv1 channel When depolarized, R3 moves upward to interact with F150 stabilizing the open state of Hv1 F150 is essential for the transfer of the Hv1 arginines in the process of voltage sensing
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Affiliation(s)
- Xin Wu
- Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Lu Zhang
- Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Liang Hong
- Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA
- Corresponding author
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9
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Saltarella I, Altamura C, Lamanuzzi A, Apollonio B, Vacca A, Frassanito MA, Desaphy JF. Ion Channels in Multiple Myeloma: Pathogenic Role and Therapeutic Perspectives. Int J Mol Sci 2022; 23:ijms23137302. [PMID: 35806308 PMCID: PMC9266328 DOI: 10.3390/ijms23137302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 06/27/2022] [Accepted: 06/27/2022] [Indexed: 12/10/2022] Open
Abstract
Ion channels are pore-forming proteins that allow ions to flow across plasma membranes and intracellular organelles in both excitable and non-excitable cells. They are involved in the regulation of several biological processes (i.e., proliferation, cell volume and shape, differentiation, migration, and apoptosis). Recently, the aberrant expression of ion channels has emerged as an important step of malignant transformation, tumor progression, and drug resistance, leading to the idea of “onco-channelopathy”. Here, we review the contribution of ion channels and transporters in multiple myeloma (MM), a hematological neoplasia characterized by the expansion of tumor plasma cells (MM cells) in the bone marrow (BM). Deregulation of ion channels sustains MM progression by modulating intracellular pathways that promote MM cells’ survival, proliferation, and drug resistance. Finally, we focus on the promising role of ion channels as therapeutic targets for the treatment of MM patients in a combination strategy with currently used anti-MM drugs to improve their cytotoxic activity and reduce adverse effects.
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Affiliation(s)
- Ilaria Saltarella
- Department of Biomedical Sciences and Human Oncology, Section of Pharmacology, University of Bari Aldo Moro Medical School, Piazza Giulio Cesare 11, I-70124 Bari, Italy
| | - Concetta Altamura
- Department of Biomedical Sciences and Human Oncology, Section of Pharmacology, University of Bari Aldo Moro Medical School, Piazza Giulio Cesare 11, I-70124 Bari, Italy
| | - Aurelia Lamanuzzi
- Department of Biomedical Sciences and Human Oncology, Section of Internal Medicine, University of Bari Aldo Moro Medical School, I-70124 Bari, Italy
| | - Benedetta Apollonio
- Department of Biomedical Sciences and Human Oncology, Section of Internal Medicine, University of Bari Aldo Moro Medical School, I-70124 Bari, Italy
| | - Angelo Vacca
- Department of Biomedical Sciences and Human Oncology, Section of Internal Medicine, University of Bari Aldo Moro Medical School, I-70124 Bari, Italy
| | - Maria Antonia Frassanito
- Department of Biomedical Sciences and Human Oncology, Section of General Pathology, University of Bari Aldo Moro Medical School, I-70124 Bari, Italy
| | - Jean-François Desaphy
- Department of Biomedical Sciences and Human Oncology, Section of Pharmacology, University of Bari Aldo Moro Medical School, Piazza Giulio Cesare 11, I-70124 Bari, Italy
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10
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Molecular determinants of inhibition of the human proton channel hHv1 by the designer peptide C6 and a bivalent derivative. Proc Natl Acad Sci U S A 2022; 119:e2120750119. [PMID: 35648818 PMCID: PMC9191634 DOI: 10.1073/pnas.2120750119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We designed C6 peptide to address the absence of specific inhibitors of human voltage-gated proton channels (hHv1). Two C6 bind to the two hHv1 voltage sensors at the resting state, inhibiting activation on depolarization. Here, we identify the C6–hHv1 binding interface using tethered-toxin variants and channel mutants, unveil an important role for negatively charged lipids, and present a model of the C6–hHv1 complex. Inspired by nature, we create a peptide with two C6 epitopes (C62) that binds to both channel subunits simultaneously, yielding picomolar affinity and significantly improved inhibition at high potentials. C6 and C62 are peptides designed to regulate hHv1, a channel involved in innate immune-system inflammatory pathophysiology, sperm capacitation, cancer-cell proliferation, and tissue damage in ischemic stroke. The human voltage-gated proton channel (hHv1) is important for control of intracellular pH. We designed C6, a specific peptide inhibitor of hHv1, to evaluate the roles of the channel in sperm capacitation and in the inflammatory immune response of neutrophils [R. Zhao et al., Proc. Natl. Acad. Sci. U.S.A. 115, E11847–E11856 (2018)]. One C6 binds with nanomolar affinity to each of the two S3–S4 voltage-sensor loops in hHv1 in cooperative fashion so that C6-bound channels require greater depolarization to open and do so more slowly. As depolarization drives hHv1 sensors outwardly, C6 affinity decreases, and inhibition is partial. Here, we identified residues essential to C6–hHv1 binding by scanning mutagenesis, five in the hHv1 S3–S4 loops and seven on C6. A structural model of the C6–hHv1 complex was then generated by molecular dynamics simulations and validated by mutant-cycle analysis. Guided by this model, we created a bivalent C6 peptide (C62) that binds simultaneously to both hHv1 subunits and fully inhibits current with picomolar affinity. The results help delineate the structural basis for C6 state-dependent inhibition, support an anionic lipid-mediated binding mechanism, and offer molecular insight into the effectiveness of engineered C6 as a therapeutic agent or lead.
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11
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Jardin C, Ohlwein N, Franzen A, Chaves G, Musset B. The pH-dependent gating of the human voltage-gated proton channel from computational simulations. Phys Chem Chem Phys 2022; 24:9964-9977. [PMID: 35445675 DOI: 10.1039/d1cp05609c] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Gating of the voltage-gated proton channel HV1 is strongly controlled by pH. There is evidence that this involves the sidechains of titratable amino acids that change their protonation state with changes of the pH. Despite experimental investigations to identify the amino acids involved in pH sensing only few progress has been made, including one histidine at the cytoplasmic side of the channel that is involved in sensing cellular pH. We have used constant pH molecular dynamics simulations in symmetrical and asymmetrical pH conditions across the membrane to investigate the pH- and ΔpH-dependent gating of the human HV1 channel. Therefore, the pKa of every titratable amino acids has been assessed in single simulations. Our simulations captured initial conformational changes between a deactivated and an activated state of the channel induced solely by changes of the pH. The pH-dependent gating is accompanied by an outward displacement of the three S4 voltage sensing arginines that moves the second arginine past the hydrophobic gasket (HG) which separates the inner and outer pores of the channel. HV1 activation, when outer pH increases, involves amino acids at the extracellular entrance of the channel that extend the network of interactions from the external solution down to the HG. Whereas, amino acids at the cytoplasmic entrance of the channel are involved in activation, when inner pH decreases, and in a network of interactions that extend from the cytoplasm up to the HG.
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Affiliation(s)
- Christophe Jardin
- Klinikum Nürnberg Medical School, CPPB, Institute of Physiology, Pathophysiology and Biophysics, Nuremberg, Germany.
| | - Niklas Ohlwein
- Klinikum Nürnberg Medical School, CPPB, Institute of Physiology, Pathophysiology and Biophysics, Nuremberg, Germany. .,Klinik für Anästhesiologie und operative Intensivmedizin, Universitätklinik der Paracelsus Medizinischen Privatuniversität, Nuremberg, Germany
| | - Arne Franzen
- Institute of Biological Information Processing, Molecular and Cellular Physiology (IBI-1), Forschungszentrum Jülich, Jülich, Germany
| | - Gustavo Chaves
- Klinikum Nürnberg Medical School, CPPB, Institute of Physiology, Pathophysiology and Biophysics, Nuremberg, Germany.
| | - Boris Musset
- Klinikum Nürnberg Medical School, CPPB, Institute of Physiology, Pathophysiology and Biophysics, Nuremberg, Germany.
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12
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Expression of H v1 proton channels in myeloid-derived suppressor cells (MDSC) and its potential role in T cell regulation. Proc Natl Acad Sci U S A 2022; 119:e2104453119. [PMID: 35377790 PMCID: PMC9169626 DOI: 10.1073/pnas.2104453119] [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] [Indexed: 12/07/2022] Open
Abstract
Immunosuppression by myeloid-derived suppressor cells (MDSC), especially near tumor surfaces, involves the extracellular production of reactive oxygen species (ROS). ROS generation in MDSC occurs during the oxidation of NADPH to NADP+, which NOX2 catalyzes. ROS react with the T cell receptor complex, abolishing the antigen presentation, which blocks the immune system elimination of the tumor cells. Extrusion of protons from MDSC by voltage-gated proton channel (Hv1) sustains ROS production. Here, we demonstrate the expression of Hv1 in mouse MDSC. In this way, Hv1 present in MDSC becomes a potential cancer therapeutic target since its inhibition seems to diminish immunosuppression activity in the tumoral microenvironment, allowing cancer cells to be attacked by the immune system. Myeloid-derived suppressor cells (MDSC) are a heterogeneous cell population with high immunosuppressive activity that proliferates in infections, inflammation, and tumor microenvironments. In tumors, MDSC exert immunosuppression mainly by producing reactive oxygen species (ROS), a process triggered by the NADPH oxidase 2 (NOX2) activity. NOX2 is functionally coupled with the Hv1 proton channel in certain immune cells to support sustained free-radical production. However, a functional expression of the Hv1 channel in MDSC has not yet been reported. Here, we demonstrate that mouse MDSC express functional Hv1 proton channel by immunofluorescence microscopy, flow cytometry, and Western blot, besides performing a biophysical characterization of its macroscopic currents via patch-clamp technique. Our results show that the immunosuppression by MDSC is conditional to their ability to decrease the proton concentration elevated by the NOX2 activity, rendering Hv1 a potential drug target for cancer treatment.
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13
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Gating Mechanism of the Voltage-Gated Proton Channel Studied by Molecular Dynamics Simulations. Molecules 2022; 27:molecules27072277. [PMID: 35408673 PMCID: PMC9000549 DOI: 10.3390/molecules27072277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/20/2022] [Accepted: 03/28/2022] [Indexed: 11/17/2022] Open
Abstract
The voltage-gated proton channel Hv1 has important roles in proton extrusion, pH homeostasis, sperm motility, and cancer progression. The Hv1 channel has also been found to be highly expressed in cell lines and tissue samples from patients with breast cancer. A high-resolution closed-state structure has been reported for the mouse Hv1 chimera channel (mHv1cc), solved by X-ray crystallography, but the open-state structure of Hv1 has not been solved. Since Hv1 is a promising drug target, various groups have proposed open conformations by molecular modeling and simulation studies. However, the gating mechanism and the open-state conformation under the membrane potential are still debate. Here, we present a molecular dynamics study considering membrane potential and pH conditions. The closed-state structure of mHv1cc was used to run molecular dynamics (MD) simulations with respect to electric field and pH conditions in order to investigate the mechanism of proton transfer. We observed a continuous hydrogen bond chain of water molecules called a water-wire to be formed through the channel pore in the channel opening, triggered by downward displacement of the S2 helix and upward movement of the S4 helix relative to other helices. Due to the movement of the S2 and S4 helices, the internal salt bridge network was rearranged, and the hydrophobic gating layers were destroyed. In line with previous experimental and simulation observations, our simulation results led us to propose a new gating mechanism for the Hv1 proton channel, and may provide valuable information for novel drug discovery.
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14
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Harguindey S, Alfarouk K, Polo Orozco J, Reshkin SJ, Devesa J. Hydrogen Ion Dynamics as the Fundamental Link between Neurodegenerative Diseases and Cancer: Its Application to the Therapeutics of Neurodegenerative Diseases with Special Emphasis on Multiple Sclerosis. Int J Mol Sci 2022; 23:ijms23052454. [PMID: 35269597 PMCID: PMC8910484 DOI: 10.3390/ijms23052454] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 02/17/2022] [Accepted: 02/21/2022] [Indexed: 02/01/2023] Open
Abstract
The pH-related metabolic paradigm has rapidly grown in cancer research and treatment. In this contribution, this recent oncological perspective has been laterally assessed for the first time in order to integrate neurodegeneration within the energetics of the cancer acid-base conceptual frame. At all levels of study (molecular, biochemical, metabolic, and clinical), the intimate nature of both processes appears to consist of opposite mechanisms occurring at the far ends of a physiopathological intracellular pH/extracellular pH (pHi/pHe) spectrum. This wide-ranging original approach now permits an increase in our understanding of these opposite processes, cancer and neurodegeneration, and, as a consequence, allows us to propose new avenues of treatment based upon the intracellular and microenvironmental hydrogen ion dynamics regulating and deregulating the biochemistry and metabolism of both cancer and neural cells. Under the same perspective, the etiopathogenesis and special characteristics of multiple sclerosis (MS) is an excellent model for the study of neurodegenerative diseases and, utilizing this pioneering approach, we find that MS appears to be a metabolic disease even before an autoimmune one. Furthermore, within this paradigm, several important aspects of MS, from mitochondrial failure to microbiota functional abnormalities, are analyzed in depth. Finally, and for the first time, a new and integrated model of treatment for MS can now be advanced.
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Affiliation(s)
- Salvador Harguindey
- Division of Oncology, Institute of Clinical Biology and Metabolism, 01004 Vitoria, Spain;
- Correspondence: ; Tel.: +34-629-047-141
| | - Khalid Alfarouk
- Institute of Endemic Diseases, University of Khartoum, Khartoum 11111, Sudan;
| | - Julián Polo Orozco
- Division of Oncology, Institute of Clinical Biology and Metabolism, 01004 Vitoria, Spain;
| | - Stephan J Reshkin
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, 70125 Bari, Italy;
| | - Jesús Devesa
- Scientific Direction, Foltra Medical Centre, 15886 Teo, Spain;
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15
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Orts DJB, Arcisio-Miranda M. Cell glycosaminoglycans content modulates human voltage-gated proton channel (H V 1) gating. FEBS J 2021; 289:2593-2612. [PMID: 34800064 DOI: 10.1111/febs.16290] [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: 09/09/2021] [Revised: 11/01/2021] [Accepted: 11/19/2021] [Indexed: 11/28/2022]
Abstract
Voltage-gated proton channels (HV 1) have been found in many mammalian cells and play a crucial role in the immune system, male fertility, and cancer progression. Glycosaminoglycans play a significant role in various aspects of cell physiology, including the modulation of membrane receptors and ion channel function. We present here evidence that mechanosensitivity of the dimeric HV 1 channel transduce changes on cell membrane fluidity related to the defective biosynthesis of chondroitin sulfate and heparan sulfate in Chinese Hamster Ovary (CHO-745) cells into a leftward shift in the activation voltage dependence. This effect was accompanied by an increase in the H+ current, and an acceleration of the activation kinetics, under symmetrical or asymmetrical pH gradient (ΔpH) conditions. Similar gating alterations were evoked by two naturally occurring HV 1 N-terminal truncated isoforms expressed in wild-type CHO-K1 and CHO-745 cells. On three different monomeric HV 1 constructs, no alterations in the biophysical parameters were observed. Moreover, we have shown that HV 1 gating can be modulated by manipulating CHO-K1 cell membrane fluidity. Our results suggest that the defective biosynthesis of chondroitin sulfate and heparan sulfate on CHO-745 cell increases membrane fluidity and allosterically modulates the coupling between voltage- and ΔpH-sensing through the dimeric HV 1 channel.
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Affiliation(s)
- Diego J B Orts
- Departamento de Biofísica, Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Universidade Federal de São Paulo - UNIFESP, Brasil
| | - Manoel Arcisio-Miranda
- Departamento de Biofísica, Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Universidade Federal de São Paulo - UNIFESP, Brasil
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16
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Di Pompo G, Cortini M, Baldini N, Avnet S. Acid Microenvironment in Bone Sarcomas. Cancers (Basel) 2021; 13:cancers13153848. [PMID: 34359749 PMCID: PMC8345667 DOI: 10.3390/cancers13153848] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/24/2021] [Accepted: 07/28/2021] [Indexed: 12/15/2022] Open
Abstract
Simple Summary Although rare, malignant bone sarcomas have devastating clinical implications for the health and survival of young adults and children. To date, efforts to identify the molecular drivers and targets have focused on cancer cells or on the interplay between cancer cells and stromal cells in the tumour microenvironment. On the contrary, in the current literature, the role of the chemical-physical conditions of the tumour microenvironment that may be implicated in sarcoma aggressiveness and progression are poorly reported and discussed. Among these, extracellular acidosis is a well-recognized hallmark of bone sarcomas and promotes cancer growth and dissemination but data presented on this topic are fragmented. Hence, we intended to provide a general and comprehensive overview of the causes and implications of acidosis in bone sarcoma. Abstract In bone sarcomas, extracellular proton accumulation is an intrinsic driver of malignancy. Extracellular acidosis increases stemness, invasion, angiogenesis, metastasis, and resistance to therapy of cancer cells. It reprograms tumour-associated stroma into a protumour phenotype through the release of inflammatory cytokines. It affects bone homeostasis, as extracellular proton accumulation is perceived by acid-sensing ion channels located at the cell membrane of normal bone cells. In bone, acidosis results from the altered glycolytic metabolism of bone cancer cells and the resorption activity of tumour-induced osteoclasts that share the same ecosystem. Proton extrusion activity is mediated by extruders and transporters located at the cell membrane of normal and transformed cells, including vacuolar ATPase and carbonic anhydrase IX, or by the release of highly acidic lysosomes by exocytosis. To date, a number of investigations have focused on the effects of acidosis and its inhibition in bone sarcomas, including studies evaluating the use of photodynamic therapy. In this review, we will discuss the current status of all findings on extracellular acidosis in bone sarcomas, with a specific focus on the characteristics of the bone microenvironment and the acid-targeting therapeutic approaches that are currently being evaluated.
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Affiliation(s)
- Gemma Di Pompo
- Biomedical Science and Technologies Lab, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (G.D.P.); (M.C.); (N.B.)
| | - Margherita Cortini
- Biomedical Science and Technologies Lab, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (G.D.P.); (M.C.); (N.B.)
| | - Nicola Baldini
- Biomedical Science and Technologies Lab, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (G.D.P.); (M.C.); (N.B.)
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy
| | - Sofia Avnet
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy
- Correspondence:
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17
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Thermodynamics and Mechanism of the Membrane Permeation of Hv1 Channel Blockers. J Membr Biol 2020; 254:5-16. [PMID: 33196887 DOI: 10.1007/s00232-020-00149-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/14/2020] [Indexed: 02/08/2023]
Abstract
The voltage-gated proton channel Hv1 mediates efflux of protons from the cell. Hv1 integrally contributes to various physiological processes including pH homeostasis and the respiratory burst of phagocytes. Inhibition of Hv1 may provide therapeutic avenues for the treatment of inflammatory diseases, breast cancer, and ischemic brain damage. In this work, we investigate two prototypical Hv1 inhibitors, 2-guanidinobenzimidazole (2GBI), and 5-chloro-2-guanidinobenzimidazole (GBIC), from an experimentally screened class of guanidine derivatives. Both compounds block proton conduction by binding the same site located on the intracellular side of the channel. However, when added to the extracellular medium, the compounds strongly differ in their ability to inhibit proton conduction, suggesting substantial differences in membrane permeability. Here, we compute the potential of mean force for each compound to permeate through the membrane using atomistic molecular dynamics simulations with the adaptive biasing force method. Our results rationalize the putative distinction between these two blockers with respect to their abilities to permeate the cellular membrane.
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18
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Lim VT, Geragotelis AD, Lim NM, Freites JA, Tombola F, Mobley DL, Tobias DJ. Insights on small molecule binding to the Hv1 proton channel from free energy calculations with molecular dynamics simulations. Sci Rep 2020; 10:13587. [PMID: 32788614 PMCID: PMC7423955 DOI: 10.1038/s41598-020-70369-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/23/2020] [Indexed: 02/07/2023] Open
Abstract
Hv1 is a voltage-gated proton channel whose main function is to facilitate extrusion of protons from the cell. The development of effective channel blockers for Hv1 can lead to new therapeutics for the treatment of maladies related to Hv1 dysfunction. Although the mechanism of proton permeation in Hv1 remains to be elucidated, a series of small molecules have been discovered to inhibit Hv1. Here, we computed relative binding free energies of a prototypical Hv1 blocker on a model of human Hv1 in an open state. We used alchemical free energy perturbation techniques based on atomistic molecular dynamics simulations. The results support our proposed open state model and shed light on the preferred tautomeric state of the channel blocker. This work lays the groundwork for future studies on adapting the blocker molecule for more effective inhibition of Hv1.
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Affiliation(s)
- Victoria T Lim
- Department of Chemistry, University of California, Irvine, CA, 92697, USA
| | | | - Nathan M Lim
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, 92697, USA
| | - J Alfredo Freites
- Department of Chemistry, University of California, Irvine, CA, 92697, USA
| | - Francesco Tombola
- Department of Physiology and Biophysics, University of California, Irvine, CA, 92697, USA
- Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, 92697, USA
| | - David L Mobley
- Department of Chemistry, University of California, Irvine, CA, 92697, USA.
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, 92697, USA.
| | - Douglas J Tobias
- Department of Chemistry, University of California, Irvine, CA, 92697, USA.
- Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, 92697, USA.
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19
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Voltage-dependent structural models of the human Hv1 proton channel from long-timescale molecular dynamics simulations. Proc Natl Acad Sci U S A 2020; 117:13490-13498. [PMID: 32461356 DOI: 10.1073/pnas.1920943117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The voltage-gated Hv1 proton channel is a ubiquitous membrane protein that has roles in a variety of cellular processes, including proton extrusion, pH regulation, production of reactive oxygen species, proliferation of cancer cells, and increased brain damage during ischemic stroke. A crystal structure of an Hv1 construct in a putative closed state has been reported, and structural models for the channel open state have been proposed, but a complete characterization of the Hv1 conformational dynamics under an applied membrane potential has been elusive. We report structural models of the Hv1 voltage-sensing domain (VSD), both in a hyperpolarized state and a depolarized state resulting from voltage-dependent conformational changes during a 10-μs-timescale atomistic molecular dynamics simulation in an explicit membrane environment. In response to a depolarizing membrane potential, the S4 helix undergoes an outward displacement, leading to changes in the VSD internal salt-bridge network, resulting in a reshaping of the permeation pathway and a significant increase in hydrogen bond connectivity throughout the channel. The total gating charge displacement associated with this transition is consistent with experimental estimates. Molecular docking calculations confirm the proposed mechanism for the inhibitory action of 2-guanidinobenzimidazole (2GBI) derived from electrophysiological measurements and mutagenesis. The depolarized structural model is also consistent with the formation of a metal bridge between residues located in the core of the VSD. Taken together, our results suggest that these structural models are representative of the closed and open states of the Hv1 channel.
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20
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Bare DJ, Cherny VV, DeCoursey TE, Abukhdeir AM, Morgan D. Expression and function of voltage gated proton channels (Hv1) in MDA-MB-231 cells. PLoS One 2020; 15:e0227522. [PMID: 32374759 PMCID: PMC7202653 DOI: 10.1371/journal.pone.0227522] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 04/09/2020] [Indexed: 02/07/2023] Open
Abstract
Expression of the voltage gated proton channel (Hv1) as identified by immunocytochemistry has been reported previously in breast cancer tissue. Increased expression of HV1 was correlated with poor prognosis and decreased overall and disease-free survival but the mechanism of its involvement in the disease is unknown. Here we present electrophysiological recordings of HV1 channel activity, confirming its presence and function in the plasma membrane of a breast cancer cell line, MDA-MB-231. With western blotting we identify significant levels of HV1 expression in 3 out of 8 “triple negative” breast cancer cell lines (estrogen, progesterone, and HER2 receptor expression negative). We examine the function of HV1 in breast cancer using MDA-MB-231 cells as a model by suppressing the expression of HV1 using shRNA (knock-down; KD) and by eliminating HV1 using CRISPR/Cas9 gene editing (knock-out; KO). Surprisingly, these two approaches produced incongruous effects. Knock-down of HV1 using shRNA resulted in slower cell migration in a scratch assay and a significant reduction in H2O2 release. In contrast, HV1 Knock-out cells did not show reduced migration or H2O2 release. HV1 KO but not KD cells showed an increased glycolytic rate accompanied by an increase in p-AKT (phospho-AKT, Ser473) activity. The expression of CD171/LCAM-1, an adhesion molecule and prognostic indicator for breast cancer, was reduced in HV1 KO cells. When we compared MDA-MB-231 xenograft growth rates in immunocompromised mice, tumors from HV1 KO cells grew less than WT in mass, with lower staining for the Ki-67 marker for cell proliferation rate. Therefore, deletion of HV1 expression in MDA-MB-231 cells limits tumor growth rate. The limited growth thus appears to be independent of oxidant production by NADPH oxidase molecules and to be mediated by cell adhesion molecules. Although HV1 KO and KD affect certain cellular mechanisms differently, both implicate HV1-mediated pathways for control of tumor growth in the MDA-MB-231 cell line.
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Affiliation(s)
- Dan J Bare
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Vladimir V Cherny
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Thomas E DeCoursey
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Abde M Abukhdeir
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL, United States of America
| | - Deri Morgan
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, MO, United States of America
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21
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The voltage-gated proton channel hHv1 is functionally expressed in human chorion-derived mesenchymal stem cells. Sci Rep 2020; 10:7100. [PMID: 32346069 PMCID: PMC7188850 DOI: 10.1038/s41598-020-63517-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/01/2020] [Indexed: 01/08/2023] Open
Abstract
The voltage-gated proton channel Hv1 is widely expressed, among others, in immune and cancer cells, it provides an efficient cytosolic H+extrusion mechanism and regulates vital functions such as oxidative burst, migration and proliferation. Here we demonstrate the presence of human Hv1 (hHv1) in the placenta/chorion-derived mesenchymal stem cells (cMSCs) using RT-PCR. The voltage- and pH-dependent gating of the current is similar to that of hHv1 expressed in cell lines and that the current is blocked by 5-chloro-2-guanidinobenzimidazole (ClGBI) and activated by arachidonic acid (AA). Inhibition of hHv1 by ClGBI significantly decreases mineral matrix production of cMSCs induced by conditions mimicking physiological or pathological (inorganic phosphate, Pi) induction of osteogenesis. Wound healing assay and single cell motility analysis show that ClGBI significantly inhibits the migration of cMSCs. Thus, seminal functions of cMSCs are modulated by hHv1 which makes this channel as an attractive target for controlling advantages/disadvantages of MSCs therapy.
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22
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Ventura C, Leon IE, Asuaje A, Martín P, Enrique N, Núñez M, Cocca C, Milesi V. Differential expression of the long and truncated Hv1 isoforms in breast-cancer cells. J Cell Physiol 2020; 235:8757-8767. [PMID: 32324259 DOI: 10.1002/jcp.29719] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 01/08/2023]
Abstract
Metabolic reprogramming of cancer cells results in a high production of acidic substances that must be extruded to maintain tumor-cell viability. The voltage-gated proton channel (Hv1) mediates highly selective effluxes of hydronium-ion (H+ ) that prevent deleterious cytoplasmic acidification. In the work described here, we demonstrated for the first time that the amino-terminal-truncated isoform of Hv1 is more highly expressed in tumorigenic breast-cancer-cell lines than in nontumorigenic breast cells. With respect to Hv1 function, we observed that pharmacologic inhibition of that channel, mediated by the specific blocker 5-chloro-2-guanidinobenzimidazole, produced a drop in intracellular pH and a decrease in cell viability, both in monolayer and in three-dimensional cultures, and adversely affected the cell-cycle in tumorigenic breast cells without altering the cycling of nontumorigenic cells. In conclusion, our results demonstrated that the Hv1 channel could be a potential tool both as a biomarker and as a therapeutic target in breast-cancer disease.
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Affiliation(s)
- Clara Ventura
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), CONICET-UNLP, La Plata, Buenos Aires, Argentina.,Laboratorio de Radioisótopos, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ignacio Esteban Leon
- Centro de Química Inorgánica (CEQUINOR), CONICET-UNLP, La Plata, Buenos Aires, Argentina
| | - Agustin Asuaje
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), CONICET-UNLP, La Plata, Buenos Aires, Argentina
| | - Pedro Martín
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), CONICET-UNLP, La Plata, Buenos Aires, Argentina
| | - Nicolas Enrique
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), CONICET-UNLP, La Plata, Buenos Aires, Argentina
| | - Mariel Núñez
- Laboratorio de Radioisótopos, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Claudia Cocca
- Laboratorio de Radioisótopos, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Química y Fisicoquímica Biológica (IQUIFIB), CONICET-UBA, Buenos Aires, Argentina
| | - Verónica Milesi
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), CONICET-UNLP, La Plata, Buenos Aires, Argentina
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23
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Chaves G, Bungert-Plümke S, Franzen A, Mahorivska I, Musset B. Zinc modulation of proton currents in a new voltage-gated proton channel suggests a mechanism of inhibition. FEBS J 2020; 287:4996-5018. [PMID: 32160407 PMCID: PMC7754295 DOI: 10.1111/febs.15291] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 01/10/2020] [Accepted: 03/10/2020] [Indexed: 02/03/2023]
Abstract
The HV1 voltage‐gated proton (HV1) channel is a key component of the cellular proton extrusion machinery and is pivotal for charge compensation during the respiratory burst of phagocytes. The best‐described physiological inhibitor of HV1 is Zn2+. Externally applied ZnCl2 drastically reduces proton currents reportedly recorded in Homo sapiens, Rattus norvegicus, Mus musculus, Oryctolagus cuniculus, Rana esculenta, Helix aspersa, Ciona intestinalis, Coccolithus pelagicus, Emiliania huxleyi, Danio rerio, Helisoma trivolvis, and Lingulodinium polyedrum, but with considerable species variability. Here, we report the effects of Zn2+ and Cd2+ on HV1 from Nicoletia phytophila, NpHV1. We introduced mutations at potential Zn2+ coordination sites and measured Zn2+ inhibition in different extracellular pH, with Zn2+ concentrations up to 1000 μm. Zn2+ inhibition in NpHV1 was quantified by the slowing of the activation time constant and a positive shift of the conductance–voltage curve. Replacing aspartate in the S3‐S4 loop with histidine (D145H) enhanced both the slowing of activation kinetics and the shift in the voltage–conductance curve, such that Zn2+ inhibition closely resembled that of the human channel. Histidine is much more effective than aspartate in coordinating Zn2+ in the S3‐S4 linker. A simple Hodgkin Huxley model of NpHV1 suggests a decrease in the opening rate if it is inhibited by zinc or cadmium. Limiting slope measurements and high‐resolution clear native gel electrophoresis (hrCNE) confirmed that NpHV1 functions as a dimer. The data support the hypothesis that zinc is coordinated in between the dimer instead of the monomer. Zinc coordination sites may be potential targets for drug development.
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Affiliation(s)
- Gustavo Chaves
- Institut für Physiologie und Pathophysiologie, Paracelsus Universität Salzburg Standort Nürnberg, Nuremberg, Germany
| | - Stefanie Bungert-Plümke
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4) Forschungszentrum Jülich, Jülich, Germany
| | - Arne Franzen
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4) Forschungszentrum Jülich, Jülich, Germany
| | - Iryna Mahorivska
- Institut für Physiologie und Pathophysiologie, Paracelsus Universität Salzburg Standort Nürnberg, Nuremberg, Germany
| | - Boris Musset
- Institut für Physiologie und Pathophysiologie, Paracelsus Universität Salzburg Standort Nürnberg, Nuremberg, Germany
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24
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Tang D, Yang Y, Xiao Z, Xu J, Yang Q, Dai H, Liang S, Tang C, Dong H, Liu Z. Scorpion toxin inhibits the voltage-gated proton channel using a Zn 2+ -like long-range conformational coupling mechanism. Br J Pharmacol 2020; 177:2351-2364. [PMID: 31975366 DOI: 10.1111/bph.14984] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 12/27/2019] [Accepted: 12/30/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Blocking the voltage-gated proton channel HV 1 is a promising strategy for the treatment of diseases like ischaemia stroke and cancer. However, few HV 1 channel antagonists have been reported. Here, we have identified a novel HV 1 channel antagonist from scorpion venom and have elucidated its action mechanism. EXPERIMENTAL APPROACH HV 1 and NaV channels were heterologously expressed in mammalian cell lines and their currents recorded using whole-cell patch clamp. Site-directed mutagenesis was used to generate mutants. Toxins were recombinantly produced in Escherichia coli. AGAP/W38F-HV 1 interaction was modelled by molecular dynamics simulations. KEY RESULTS The scorpion toxin AGAP (anti-tumour analgesic peptide) potently inhibited HV 1 currents. One AGAP mutant has reduced NaV channel activity but intact HV 1 activity (AGAP/W38F). AGAP/W38F inhibited HV 1 channel activation by trapping its S4 voltage sensor in a deactivated state and inhibited HV 1 currents with less pH dependence than Zn2+ . Mutation analysis showed that the binding pockets of AGAP/W38F and Zn2+ in HV 1 channel partly overlapped (common sites are His140 and His193). The E153A mutation at the intracellular Coulombic network (ICN) in HV 1 channel markedly reduced AGAP/W38F inhibition, as observed for Zn2+ . Experimental data and MD simulations suggested that AGAP/W38F inhibited HV 1 channel using a Zn2+ -like long-range conformational coupling mechanism. CONCLUSION AND IMPLICATIONS Our results suggest that the Zn2+ binding pocket in HV 1 channel might be a hotspot for modulators and valuable for designing HV 1 channel ligands. Moreover, AGAP/W38F is a useful molecular probe to study HV 1 channel and a lead compound for drug development.
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Affiliation(s)
- Dongfang Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Yuqin Yang
- Kuang Yaming Honors School, Nanjing University, Nanjing, China.,Institute for Brain Sciences, Nanjing University, Nanjing, China
| | - Zhen Xiao
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Jiahui Xu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Qiuchu Yang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Han Dai
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Songping Liang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Cheng Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Hao Dong
- Kuang Yaming Honors School, Nanjing University, Nanjing, China.,Institute for Brain Sciences, Nanjing University, Nanjing, China
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
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25
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Xiao B, Shi X, Bai J. miR-30a regulates the proliferation and invasion of breast cancer cells by targeting Snail. Oncol Lett 2018; 17:406-413. [PMID: 30655781 DOI: 10.3892/ol.2018.9552] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/07/2018] [Indexed: 02/07/2023] Open
Abstract
The present study aims to investigate the effect of miR-30a on the proliferative and invasive abilities of breast cancer cells, and to observe the role of miR-30a in the pathogenesis of breast cancer. With the increase of pathological grade and malignant degree of breast cancer cells, the miR-30a expression level gradually decreased (P<0.01). Transfection with miR-30a mimic significantly inhibited the proliferative and invasive ability of SK-BR-3 cells (P<0.01), while transfection with anti-miR-30a significantly improved the proliferative and invasive ability of these cells (P<0.01). It was revealed using bioinformatic methods that Snail was the functional target gene of miR-30a, and this was verified by the results of a luciferase reporter gene assay. The results of analysis of Snail expression in breast cancer tissues and breast cancer cells revealed that with the increase in pathological grade and malignant degree of breast cancer cells, Snail expression levels gradually increased (P<0.01). Western blotting revealed that miR-30a significantly inhibited Snail expression in SK-BR-3 cells, upregulated the expression of EMT-associated E-cadherin, and downregulated the expression of EMT-associated N-cadherin and Vimentin. MiR-30a was able to affect the proliferation and invasion of breast cancer cells by regulating Snail expression, and therefore has a regulatory effect on the occurrence and development of breast cancer.
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Affiliation(s)
- Baoqiang Xiao
- Department of General Surgery, No. 254 Hospital of The People's Liberation Army, Tianjin 300142, P.R. China
| | - Xuejing Shi
- Department of Breast Surgery, Tianjin Central Obstetrics and Gynecology Hospital, Tianjin 300142, P.R. China
| | - Jianping Bai
- Department of General Surgery, No. 254 Hospital of The People's Liberation Army, Tianjin 300142, P.R. China
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26
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Chow LW, Cheng KS, Wong KL, Leung YM. Voltage-gated K + channels promote BT-474 breast cancer cell migration. Chin J Cancer Res 2018; 30:613-622. [PMID: 30700930 PMCID: PMC6328511 DOI: 10.21147/j.issn.1000-9604.2018.06.06] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Objective A variety of ion channels have been implicated in breast cancer proliferation and metastasis. Voltage-gated K+ (Kv) channels not only cause repolarization in excitable cells, but are also involved in multiple cellular functions in non-excitable cells. In this study we investigated the role of Kv channels in migration of BT474 breast cancer cells. Methods Transwell technique was used to separate migratory cells from non-migratory ones and these two groups of cells were subject to electrophysiological examinations and microfluorimetric measurements for cytosolic Ca2+. Cell migration was examined in the absence or presence of Kv channel blockers. Results When compared with non-migratory cells, migratory cells had much higher Kv current densities, but rather unexpectedly, more depolarized membrane potential and reduced Ca2+ influx. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed the presence of Kv1.1, Kv1.3, Kv1.5, Kv2.1, Kv3.3, Kv3.4 and Kv4.3 channels. Cell migration was markedly inhibited by tetraethylammonium (TEA), a delayed rectifier Kv channel blocker, but not by 4-aminopyridine, an A-type Kv channel blocker. Conclusions Taken together, our results show that increased Kv channel expression played a role in BT474 cell migration, and Kv channels could be considered as biomarkers or potential therapeutic targets for breast cancer metastasis. The mechanism(s) by which Kv channels enhanced migration appeared unrelated to membrane hyperpolarization and Ca2+ influx.
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Affiliation(s)
- Louis Wc Chow
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Taipa, Macau 999078, China.,UNIMED Medical Institute, Hong Kong 999077, China.,Organisation for Oncology and Translational Research, Hong Kong 999077, China
| | - Ka-Shun Cheng
- Department of Anesthesiology, China Medical University Hospital, Taichung 40447, Taiwan, China.,Department of Anesthesiology, the Qingdao University Yuhuangding Hospital, Yantai 264000, China
| | - Kar-Lok Wong
- Department of Anesthesiology, China Medical University Hospital, Taichung 40447, Taiwan, China
| | - Yuk-Man Leung
- Department of Physiology, China Medical University, Taichung 40402, Taiwan, China
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27
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Asuaje A, Martín P, Enrique N, Zegarra LAD, Smaldini P, Docena G, Milesi V. Diphenhydramine inhibits voltage-gated proton channels (Hv1) and induces acidification in leukemic Jurkat T cells- New insights into the pro-apoptotic effects of antihistaminic drugs. Channels (Austin) 2018; 12:58-64. [PMID: 28514187 PMCID: PMC5972794 DOI: 10.1080/19336950.2017.1331799] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 05/09/2017] [Accepted: 05/10/2017] [Indexed: 12/22/2022] Open
Abstract
An established characteristic of neoplastic cells is their metabolic reprogramming, known as the Warburg effect, with greater reliance on energetically less efficient pathways (such as glycolysis and pentose phosphate shunt) compared with oxidative phosphorylation. This results in an overproduction of acidic species that must be extruded to maintain intracellular homeostasis. We recently described that blocking the proton currents in leukemic cells mediated by Hv1 ion channels triggers a marked intracellular acidification and apoptosis induction. Moreover, histamine H1-receptor antagonists were found to induce apoptosis in tumoral cells but the mechanism is still unclear. By using Jurkat T cells, we now show how diphenhydramine inhibits Hv1 mediated currents, inducing a drop in intracellular pH and cellular viability. This provides evidence of a new target structure responsible of the known pro-apoptotic action of antihistaminic drugs.
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Affiliation(s)
- Agustín Asuaje
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET—Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Pedro Martín
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET—Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Nicolás Enrique
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET—Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Leandro Agustín Díaz Zegarra
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET—Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Paola Smaldini
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET—Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Guillermo Docena
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET—Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Verónica Milesi
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET—Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
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28
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Harguindey S, Stanciu D, Devesa J, Alfarouk K, Cardone RA, Polo Orozco JD, Devesa P, Rauch C, Orive G, Anitua E, Roger S, Reshkin SJ. Cellular acidification as a new approach to cancer treatment and to the understanding and therapeutics of neurodegenerative diseases. Semin Cancer Biol 2017; 43:157-179. [PMID: 28193528 DOI: 10.1016/j.semcancer.2017.02.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/06/2017] [Indexed: 12/27/2022]
Abstract
During the last few years, the understanding of the dysregulated hydrogen ion dynamics and reversed proton gradient of cancer cells has resulted in a new and integral pH-centric paradigm in oncology, a translational model embracing from cancer etiopathogenesis to treatment. The abnormalities of intracellular alkalinization along with extracellular acidification of all types of solid tumors and leukemic cells have never been described in any other disease and now appear to be a specific hallmark of malignancy. As a consequence of this intracellular acid-base homeostatic failure, the attempt to induce cellular acidification using proton transport inhibitors and other intracellular acidifiers of different origins is becoming a new therapeutic concept and selective target of cancer treatment, both as a metabolic mediator of apoptosis and in the overcoming of multiple drug resistance (MDR). Importantly, there is increasing data showing that different ion channels contribute to mediate significant aspects of cancer pH regulation and etiopathogenesis. Finally, we discuss the extension of this new pH-centric oncological paradigm into the opposite metabolic and homeostatic acid-base situation found in human neurodegenerative diseases (HNDDs), which opens novel concepts in the prevention and treatment of HNDDs through the utilization of a cohort of neural and non-neural derived hormones and human growth factors.
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Affiliation(s)
- Salvador Harguindey
- Institute of Clinical Biology and Metabolism, c) Postas 13, 01004 Vitoria, Spain.
| | - Daniel Stanciu
- Institute of Clinical Biology and Metabolism, c) Postas 13, 01004 Vitoria, Spain
| | - Jesús Devesa
- Department of Physiology, School of Medicine, University of Santiago de Compostela, Spain and Scientific Director of Foltra Medical Centre, Teo, Spain
| | - Khalid Alfarouk
- Al-Ghad International Colleges for Applied Medical Sciences, Al-Madinah Al-Munawarah, Saudi Arabia
| | - Rosa Angela Cardone
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy
| | | | - Pablo Devesa
- Research and Development, Medical Centre Foltra, Teo, Spain
| | - Cyril Rauch
- School of Veterinary Medicine and Science, University of Nottingham,College Road, Sutton Bonington, LE12 5RD, UK
| | - Gorka Orive
- Laboratory of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of the Basque Country, Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine, CIBER-BBN, SLFPB-EHU, 01006 Vitoria, Spain
| | - Eduardo Anitua
- BTI Biotechnology Institute ImasD, S.L. C/Jacinto Quincoces, 39, 01007 Vitoria, Spain
| | - Sébastien Roger
- Inserm UMR1069, University François-Rabelais of Tours,10 Boulevard Tonnellé, 37032 Tours, France; Institut Universitaire de France, 1 Rue Descartes, Paris 75231, France
| | - Stephan J Reshkin
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy
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29
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Gianti E, Delemotte L, Klein ML, Carnevale V. On the role of water density fluctuations in the inhibition of a proton channel. Proc Natl Acad Sci U S A 2016; 113:E8359-E8368. [PMID: 27956641 PMCID: PMC5206518 DOI: 10.1073/pnas.1609964114] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hv1 is a transmembrane four-helix bundle that transports protons in a voltage-controlled manner. Its crucial role in many pathological conditions, including cancer and ischemic brain damage, makes Hv1 a promising drug target. Starting from the recently solved crystal structure of Hv1, we used structural modeling and molecular dynamics simulations to characterize the channel's most relevant conformations along the activation cycle. We then performed computational docking of known Hv1 inhibitors, 2-guanidinobenzimidazole (2GBI) and analogs. Although salt-bridge patterns and electrostatic potential profiles are well-defined and distinctive features of activated versus nonactivated states, the water distribution along the channel lumen is dynamic and reflects a conformational heterogeneity inherent to each state. In fact, pore waters assemble into intermittent hydrogen-bonded clusters that are replaced by the inhibitor moieties upon ligand binding. The entropic gain resulting from releasing these conformationally restrained waters to the bulk solvent is likely a major contributor to the binding free energy. Accordingly, we mapped the water density fluctuations inside the pore of the channel and identified the regions of maximum fluctuation within putative binding sites. Two sites appear as outstanding: One is the already known binding pocket of 2GBI, which is accessible to ligands from the intracellular side; the other is a site located at the exit of the proton permeation pathway. Our analysis of the waters confined in the hydrophobic cavities of Hv1 suggests a general strategy for drug discovery that can be applied to any ion channel.
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Affiliation(s)
- Eleonora Gianti
- Institute for Computational Molecular Science, Department of Chemistry, Temple University, Philadelphia, PA 19122
| | - Lucie Delemotte
- Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Michael L Klein
- Institute for Computational Molecular Science, Department of Chemistry, Temple University, Philadelphia, PA 19122;
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, Department of Chemistry, Temple University, Philadelphia, PA 19122;
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30
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Asuaje A, Smaldini P, Martín P, Enrique N, Orlowski A, Aiello EA, Gonzalez León C, Docena G, Milesi V. The inhibition of voltage-gated H + channel (HVCN1) induces acidification of leukemic Jurkat T cells promoting cell death by apoptosis. Pflugers Arch 2016; 469:251-261. [PMID: 28013412 DOI: 10.1007/s00424-016-1928-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 12/05/2016] [Accepted: 12/06/2016] [Indexed: 11/26/2022]
Abstract
Cellular energetic deregulation is widely known to produce an overproduction of acidic species in cancer cells. This acid overload must be counterbalanced with a high rate of H+ extrusion to maintain cell viability. In this sense, many H+ transporters have been reported to be crucial for cell survival and proposed as antineoplastic target. By the way, voltage-gated proton channels (Hv1) mediate highly selective H+ outward currents, capable to compensate acid burden in brief periods of time. This structure is canonically described acting as NADPH oxidase counterbalance in reactive oxygen species production. In this work, we show, for the first time in a oncohematologic cell line, that inhibition of Hv1 channels by Zn2+ and the more selective blocker 2-(6-chloro-1H-benzimidazol-2-yl)guanidine (ClGBI) progressively decreases intracellular pH in resting conditions. This acidification is evident minutes after blockade and progresses under prolonged exposure (2, 17, and 48 h), and we firstly demonstrate that this is followed by cell death through apoptosis (annexin V binding). Altogether, these results contribute strong evidence that this channel might be a new therapeutic target in cancer.
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Affiliation(s)
- Agustín Asuaje
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET-Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900, La Plata, Argentina
| | - Paola Smaldini
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET-Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900, La Plata, Argentina
| | - Pedro Martín
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET-Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900, La Plata, Argentina.
| | - Nicolás Enrique
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET-Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900, La Plata, Argentina
| | - Alejandro Orlowski
- Centro de Investigaciones Cardiovasculares (CIC, CONICET-Universidad Nacional de la Plata), Fac. de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, 1900, La Plata, Argentina
| | - Ernesto A Aiello
- Centro de Investigaciones Cardiovasculares (CIC, CONICET-Universidad Nacional de la Plata), Fac. de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, 1900, La Plata, Argentina
| | - Carlos Gonzalez León
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Chile, Pasaje Harrington 287, Playa Ancha, Valparaíso, Chile
| | - Guillermo Docena
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET-Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900, La Plata, Argentina
| | - Verónica Milesi
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET-Universidad Nacional de la Plata), Fac. de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900, La Plata, Argentina
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31
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Pathak MM, Tran T, Hong L, Joós B, Morris CE, Tombola F. The Hv1 proton channel responds to mechanical stimuli. J Gen Physiol 2016; 148:405-418. [PMID: 27799320 PMCID: PMC5089936 DOI: 10.1085/jgp.201611672] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 09/22/2016] [Indexed: 12/21/2022] Open
Abstract
The voltage-gated proton channel, Hv1, is expressed in tissues throughout the body and plays important roles in pH homeostasis and regulation of NADPH oxidase. Hv1 operates in membrane compartments that experience strong mechanical forces under physiological or pathological conditions. In microglia, for example, Hv1 activity is potentiated by cell swelling and causes an increase in brain damage after stroke. The channel complex consists of two proton-permeable voltage-sensing domains (VSDs) linked by a cytoplasmic coiled-coil domain. Here, we report that these VSDs directly respond to mechanical stimuli. We find that membrane stretch facilitates Hv1 channel opening by increasing the rate of activation and shifting the steady-state activation curve to less depolarized potentials. In the presence of a transmembrane pH gradient, membrane stretch alone opens the channel without the need for strong depolarizations. The effect of membrane stretch persists for several minutes after the mechanical stimulus is turned off, suggesting that the channel switches to a "facilitated" mode in which opening occurs more readily and then slowly reverts to the normal mode observed in the absence of membrane stretch. Conductance simulations with a six-state model recapitulate all the features of the channel's response to mechanical stimulation. Hv1 mechanosensitivity thus provides a mechanistic link between channel activation in microglia and brain damage after stroke.
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Affiliation(s)
- Medha M Pathak
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
| | - Truc Tran
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
| | - Liang Hong
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
| | - Béla Joós
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | | | - Francesco Tombola
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
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32
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Yang DQ, Freund DM, Harris BRE, Wang D, Cleary MP, Hegeman AD. Measuring relative utilization of aerobic glycolysis in breast cancer cells by positional isotopic discrimination. FEBS Lett 2016; 590:3179-87. [PMID: 27531463 DOI: 10.1002/1873-3468.12360] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 08/01/2016] [Accepted: 08/10/2016] [Indexed: 12/22/2022]
Abstract
The ability of cancer cells to produce lactate through aerobic glycolysis is a hallmark of cancer. In this study, we established a positional isotopic labeling and LC-MS-based method that can specifically measure the conversion of glucose to lactate in glycolysis. We show that the rate of aerobic glycolysis is closely correlated with glucose uptake and lactate production in breast cancer cells. We also found that the production of [3-(13) C]lactate is significantly elevated in metastatic breast cancer cells and in early stage metastatic mammary tumors in mice. Our findings may enable the development of a biomarker for the diagnosis of aggressive breast cancer.
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Affiliation(s)
- Da-Qing Yang
- The Hormel Institute, University of Minnesota, Austin, MN, USA. , .,The Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA. ,
| | - Dana M Freund
- Department of Horticultural Science, University of Minnesota, Twin Cities, MN, USA
| | | | - Defeng Wang
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - Margot P Cleary
- The Hormel Institute, University of Minnesota, Austin, MN, USA.,The Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Adrian D Hegeman
- Department of Horticultural Science, University of Minnesota, Twin Cities, MN, USA. .,Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, MN, USA. .,Department of Plant Biology, University of Minnesota, Twin Cities, MN, USA.
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33
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Ribeiro-Silva L, Queiroz FO, da Silva AMB, Hirata AE, Arcisio-Miranda M. Voltage-Gated Proton Channel in Human Glioblastoma Multiforme Cells. ACS Chem Neurosci 2016; 7:864-9. [PMID: 27225904 DOI: 10.1021/acschemneuro.6b00083] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Solid tumors tend to have a more glycolytic metabolism leading to an accumulation of acidic metabolites in their cytosol, and consequently, their intracellular pH (pHi) turns critically lower if the cells do not handle the acid excess. Recently, it was proposed that the voltage gated proton channels (HV1) can regulate the pHi in several cancers. Here we report the functional expression of voltage gated proton channels in a human glioblastoma multiforme (GBM) cell line, the most common and lethal brain tumor. T98G cells presented an outward, slow activating voltage-dependent proton current, which was also ΔpH-dependent and inhibited by ZnCl2, characterizing it as being conducted by HV1 channels. Furthermore, blocking HV1 channels with ZnCl2 significantly reduced the pHi, cell survival, and migration, indicating an important role for HV1 for tumor proliferation and progression in GBM. Overall, our results suggest that HV1 channels can be a new therapeutic target for GBM.
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Affiliation(s)
- Luisa Ribeiro-Silva
- Laboratório
de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica,
Escola Paulista de Medicina, Universidade Federal de São Paulo, 04023-060 São Paulo, SP Brasil
| | - Fernanda Oliveira Queiroz
- Laboratório
de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica,
Escola Paulista de Medicina, Universidade Federal de São Paulo, 04023-060 São Paulo, SP Brasil
| | - Annielle Mendes Brito da Silva
- Laboratório
de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica,
Escola Paulista de Medicina, Universidade Federal de São Paulo, 04023-060 São Paulo, SP Brasil
| | - Aparecida Emiko Hirata
- Departamento
de Fisiologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, 04023-060 São Paulo, SP Brasil
| | - Manoel Arcisio-Miranda
- Laboratório
de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica,
Escola Paulista de Medicina, Universidade Federal de São Paulo, 04023-060 São Paulo, SP Brasil
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34
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Fernández A, Pupo A, Mena-Ulecia K, Gonzalez C. Pharmacological Modulation of Proton Channel Hv1 in Cancer Therapy: Future Perspectives. Mol Pharmacol 2016; 90:385-402. [PMID: 27260771 DOI: 10.1124/mol.116.103804] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 06/02/2016] [Indexed: 12/23/2022] Open
Abstract
The pharmacological modulation of the immunosuppressive tumor microenvironment has emerged as a relevant component for cancer therapy. Several approaches aiming to deplete innate and adaptive suppressive populations, to circumvent the impairment in antigen presentation, and to ultimately increase the frequency of activated tumor-specific T cells are currently being explored. In this review, we address the potentiality of targeting the voltage-gated proton channel, Hv1, as a novel strategy to modulate the tumor microenvironment. The function of Hv1 in immune cells such as macrophages, neutrophils, dendritic cells, and T cells has been associated with the maintenance of NADPH oxidase activity and the generation of reactive oxygen species, which are required for the host defense against pathogens. We discuss evidence suggesting that the Hv1 proton channel could also be important for the function of these cells within the tumor microenvironment. Furthermore, as summarized here, tumor cells express Hv1 as a primary mechanism to extrude the increased amount of protons generated metabolically, thus maintaining physiologic values for the intracellular pH. Therefore, because this channel might be relevant for both tumor cells and immune cells supporting tumor growth, the pharmacological inhibition of Hv1 could be an innovative approach for cancer therapy. With that focus, we analyzed the available compounds that inhibit Hv1, highlighted the need to develop better drugs suitable for patients, and commented on the future perspectives of targeting Hv1 in the context of cancer therapy.
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Affiliation(s)
- Audry Fernández
- Interdisciplinary Center for Neurosciences of Valparaíso, Faculty of Sciences, University of Valparaíso, Chile
| | - Amaury Pupo
- Interdisciplinary Center for Neurosciences of Valparaíso, Faculty of Sciences, University of Valparaíso, Chile
| | - Karel Mena-Ulecia
- Interdisciplinary Center for Neurosciences of Valparaíso, Faculty of Sciences, University of Valparaíso, Chile
| | - Carlos Gonzalez
- Interdisciplinary Center for Neurosciences of Valparaíso, Faculty of Sciences, University of Valparaíso, Chile
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Chaves G, Derst C, Franzen A, Mashimo Y, Machida R, Musset B. Identification of an HV
1 voltage-gated proton channel in insects. FEBS J 2016; 283:1453-64. [DOI: 10.1111/febs.13680] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 01/05/2016] [Accepted: 02/09/2016] [Indexed: 12/26/2022]
Affiliation(s)
- Gustavo Chaves
- Institute of Complex Systems; Zelluläre Biophysik (ICS-4) Forschungszentrum Jülich; Germany
| | - Christian Derst
- Zoologisches Institut; Biozentrum Universität zu Köln; Germany
| | - Arne Franzen
- Institute of Complex Systems; Zelluläre Biophysik (ICS-4) Forschungszentrum Jülich; Germany
| | - Yuta Mashimo
- Sugadaira Montane Research Center; University of Tsukuba; Ueda Japan
| | - Ryuichiro Machida
- Sugadaira Montane Research Center; University of Tsukuba; Ueda Japan
| | - Boris Musset
- Institute of Complex Systems; Zelluläre Biophysik (ICS-4) Forschungszentrum Jülich; Germany
- Institut für Physiologie und Pathophysiologie; Paracelsus Universität Salzburg Standort Nürnberg; Nuremberg Germany
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36
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Zhao Q, Che Y, Li Q, Zhang S, Gao YT, Wang Y, Wang X, Xi W, Zuo W, Li SJ. The voltage-gated proton channel Hv1 is expressed in pancreatic islet β-cells and regulates insulin secretion. Biochem Biophys Res Commun 2015; 468:746-51. [PMID: 26559003 DOI: 10.1016/j.bbrc.2015.11.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 11/04/2015] [Indexed: 10/22/2022]
Abstract
The voltage-gated proton channel Hv1 is a potent acid extruder that participates in the extrusion of the intracellular acid. Here, we showed for the first time, Hv1 is highly expressed in mouse and human pancreatic islet β-cells, as well as β-cell lines. Imaging studies demonstrated that Hv1 resides in insulin-containing granules in β-cells. Knockdown of Hv1 with RNA interference significantly reduces glucose- and K(+)-induced insulin secretion in isolated islets and INS-1 (832/13) β-cells and has an impairment on glucose- and K(+)-induced intracellular Ca(2+) homeostasis. Our data demonstrated that the expression of Hv1 in pancreatic islet β-cells regulates insulin secretion through regulating Ca(2+) homeostasis.
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Affiliation(s)
- Qing Zhao
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, PR China
| | - Yongzhe Che
- School of Medicine, Nankai University, Tianjin 300071, PR China
| | - Qiang Li
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, PR China
| | - Shangrong Zhang
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, PR China
| | - Ying-Tang Gao
- Key Laboratory of Artificial Cell, Third Central Clinical College of Tianjin Medical University, Tianjin 300170, PR China
| | - Yifan Wang
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, PR China
| | - Xudong Wang
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, PR China
| | - Wang Xi
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, PR China
| | - Weiyan Zuo
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, PR China
| | - Shu Jie Li
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, PR China.
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Castillo K, Pupo A, Baez-Nieto D, Contreras GF, Morera FJ, Neely A, Latorre R, Gonzalez C. Voltage-gated proton (H(v)1) channels, a singular voltage sensing domain. FEBS Lett 2015; 589:3471-8. [PMID: 26296320 DOI: 10.1016/j.febslet.2015.08.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 12/28/2022]
Abstract
The main role of voltage-gated proton channels (Hv1) is to extrude protons from the intracellular milieu when, mediated by different cellular processes, the H(+) concentration increases. Hv1 are exquisitely selective for protons and their structure is homologous to the voltage sensing domain (VSD) of other voltage-gated ion channels like sodium, potassium, and calcium channels. In clear contrast to the classical voltage-dependent channels, Hv1 lacks a pore domain and thus permeation necessarily occurs through the voltage sensing domain. Hv1 channels are activated by depolarizing voltages, and increases in internal proton concentration. It has been proposed that local conformational changes of the transmembrane segment S4, driven by depolarization, trigger the molecular rearrangements that open Hv1. However, it is still unclear how the electromechanical coupling is achieved between the VSD and the potential pore, allowing the proton flux from the intracellular to the extracellular side. Here we provide a revised view of voltage activation in Hv1 channels, offering a comparative scenario with other voltage sensing channels domains.
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Affiliation(s)
- Karen Castillo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
| | - Amaury Pupo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
| | - David Baez-Nieto
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
| | - Gustavo F Contreras
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
| | - Francisco J Morera
- Institute of Pharmacology and Morphophysiology, Faculty of Veterinary Sciences, Universidad Austral de Chile, Valdivia, Chile
| | - Alan Neely
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile.
| | - Carlos Gonzalez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile.
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Seredenina T, Demaurex N, Krause KH. Voltage-Gated Proton Channels as Novel Drug Targets: From NADPH Oxidase Regulation to Sperm Biology. Antioxid Redox Signal 2015; 23:490-513. [PMID: 24483328 PMCID: PMC4543398 DOI: 10.1089/ars.2013.5806] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
SIGNIFICANCE Voltage-gated proton channels are increasingly implicated in cellular proton homeostasis. Proton currents were originally identified in snail neurons less than 40 years ago, and subsequently shown to play an important auxiliary role in the functioning of reactive oxygen species (ROS)-generating nicotinamide adenine dinucleotide phosphate (NADPH) oxidases. Molecular identification of voltage-gated proton channels was achieved less than 10 years ago. Interestingly, so far, only one gene coding for voltage-gated proton channels has been identified, namely hydrogen voltage-gated channel 1 (HVCN1), which codes for the HV1 proton channel protein. Over the last years, the first picture of putative physiological functions of HV1 has been emerging. RECENT ADVANCES The best-studied role remains charge and pH compensation during the respiratory burst of the phagocyte NADPH oxidase (NOX). Strong evidence for a role of HV1 is also emerging in sperm biology, but the relationship with the sperm NOX5 remains unclear. Probably in many instances, HV1 functions independently of NOX: for example in snail neurons, basophils, osteoclasts, and cancer cells. CRITICAL ISSUES Generally, ion channels are good drug targets; however, this feature has so far not been exploited for HV1, and hitherto no inhibitors compatible with clinical use exist. However, there are emerging indications for HV1 inhibitors, ranging from diseases with a strong activation of the phagocyte NOX (e.g., stroke) to infertility, osteoporosis, and cancer. FUTURE DIRECTIONS Clinically useful HV1-active drugs should be developed and might become interesting drugs of the future.
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Affiliation(s)
- Tamara Seredenina
- 1 Department of Pathology and Immunology, Geneva University Medical Faculty , Centre Médical Universitaire, Geneva, Switzerland
| | - Nicolas Demaurex
- 2 Department of Cellular Physiology and Metabolism, Geneva University Medical Faculty , Centre Médical Universitaire, Geneva, Switzerland
| | - Karl-Heinz Krause
- 1 Department of Pathology and Immunology, Geneva University Medical Faculty , Centre Médical Universitaire, Geneva, Switzerland .,3 Department of Genetic and Laboratory Medicine, Geneva University Hospitals , Centre Médical Universitaire, Geneva, Switzerland
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Abstract
The main properties of the voltage-gated proton channel (HV1) are described in this review, along with what is known about how the channel protein structure accomplishes its functions. Just as protons are unique among ions, proton channels are unique among ion channels. Their four transmembrane helices sense voltage and the pH gradient and conduct protons exclusively. Selectivity is achieved by the unique ability of H3O(+) to protonate an Asp-Arg salt bridge. Pathognomonic sensitivity of gating to the pH gradient ensures HV1 channel opening only when acid extrusion will result, which is crucial to most of its biological functions. An exception occurs in dinoflagellates in which influx of H(+) through HV1 triggers the bioluminescent flash. Pharmacological interventions that promise to ameliorate cancer, asthma, brain damage in ischemic stroke, Alzheimer's disease, autoimmune diseases, and numerous other conditions await future progress.
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Affiliation(s)
- Thomas E. DeCoursey
- Department of Molecular Biophysics and Physiology, Rush University, 1750 West Harrison, Chicago IL, 60612 USA
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40
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Barghouth PG, Thiruvalluvan M, Oviedo NJ. Bioelectrical regulation of cell cycle and the planarian model system. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2629-37. [PMID: 25749155 DOI: 10.1016/j.bbamem.2015.02.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 02/13/2015] [Accepted: 02/23/2015] [Indexed: 12/27/2022]
Abstract
Cell cycle regulation through the manipulation of endogenous membrane potentials offers tremendous opportunities to control cellular processes during tissue repair and cancer formation. However, the molecular mechanisms by which biophysical signals modulate the cell cycle remain underappreciated and poorly understood. Cells in complex organisms generate and maintain a constant voltage gradient across the plasma membrane known as the transmembrane potential. This potential, generated through the combined efforts of various ion transporters, pumps and channels, is known to drive a wide range of cellular processes such as cellular proliferation, migration and tissue regeneration while its deregulation can lead to tumorigenesis. These cellular regulatory events, coordinated by ionic flow, correspond to a new and exciting field termed molecular bioelectricity. We aim to present a brief discussion on the biophysical machinery involving membrane potential and the mechanisms mediating cell cycle progression and cancer transformation. Furthermore, we present the planarian Schmidtea mediterranea as a tractable model system for understanding principles behind molecular bioelectricity at both the cellular and organismal level. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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Affiliation(s)
- Paul G Barghouth
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California at Merced, 5200 North Lake Road, Merced, CA 95343, USA; Quantitative and Systems Biology Graduate Program, University of California at Merced, 5200 North Lake Road, Merced, CA 95343, USA
| | - Manish Thiruvalluvan
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California at Merced, 5200 North Lake Road, Merced, CA 95343, USA; Quantitative and Systems Biology Graduate Program, University of California at Merced, 5200 North Lake Road, Merced, CA 95343, USA
| | - Néstor J Oviedo
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California at Merced, 5200 North Lake Road, Merced, CA 95343, USA; Quantitative and Systems Biology Graduate Program, University of California at Merced, 5200 North Lake Road, Merced, CA 95343, USA; Health Sciences Research Institute, University of California at Merced, 5200 North Lake Road, Merced, CA 95343, USA.
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41
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Zhao Q, Li C, Li SJ. The pH-sensitive structure of the C-terminal domain of voltage-gated proton channel and the thermodynamic characteristics of Zn2+ binding to this domain. Biochem Biophys Res Commun 2015; 456:207-12. [DOI: 10.1016/j.bbrc.2014.11.060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 11/14/2014] [Indexed: 02/07/2023]
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Agharkar A, Rzadkowolski J, McBroom M, Gonzales EB. Detergent screening of the human voltage-gated proton channel using fluorescence-detection size-exclusion chromatography. Protein Sci 2014; 23:1136-47. [PMID: 24863684 DOI: 10.1002/pro.2492] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 05/13/2014] [Accepted: 05/22/2014] [Indexed: 11/06/2022]
Abstract
The human voltage-gated proton channel (Hv1) is a membrane protein consisting of four transmembrane domains and intracellular amino- and carboxy-termini. The protein is activated by membrane depolarization, similar to other voltage-sensitive proteins. However, the Hv1 proton channel lacks a traditional ion pore. The human Hv1 proton channel has been implicated in mediating sperm capacitance, stroke, and most recently as a biomarker/mediator of cancer metastasis. Recently, the three-dimensional structures for homologues of this voltage-gated proton channel were reported. However, it is not clear what artificial environment is needed to facilitate the isolation and purification of the human Hv1 proton channel for structural study. In the present study, we generated a chimeric protein that placed an enhanced green fluorescent protein (EGFP) to the amino-terminus of the human Hv1 proton channel (termed EGFP-Hv1). The chimeric protein was expressed in a baculovirus expression system using Sf9 cells and subjected to detergent screening using fluorescence-detection size-exclusion chromatography. The EGFP-Hv1 proton channel can be solubilized in the zwitterionic detergent Anzergent 3-12 and the nonionic n-dodecyl-β-d-maltoside (DDM) with little protein aggregation and a prominent monomeric protein peak at 48 h postinfection. Furthermore, we demonstrate that the chimeric protein exhibits a monomeric protein peak, which is distinguishable from protein aggregates, at the final size-exclusion chromatography purification step. Taken together, we can conclude that solubilization in DDM will provide a useable final product for further structural characterization of the full-length human Hv1 proton channel.
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Affiliation(s)
- Amruta Agharkar
- Department of Pharmacology & Neuroscience, UNT Health Science Center, Fort Worth, Texas
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43
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44
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Zhao Q, Zhang Y, Li SJ. Interaction of divalent metal ions with the carboxyl-terminal domain of human voltage-gated proton channel Hv1. Biometals 2014; 27:793-802. [PMID: 24867409 DOI: 10.1007/s10534-014-9751-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 05/14/2014] [Indexed: 11/25/2022]
Abstract
The voltage-gated proton channel Hv1 functions as a dimer, in which the intracellular C-terminal domain of the protein is responsible for the dimeric architecture and regulates proton permeability. Although it is well known that divalent metal ions have effect on the proton channel activity, the interaction of divalent metal ions with the channel in detail is not well elucidated. Herein, we investigated the interaction of divalent metal ions with the C-terminal domain of human Hv1 by CD spectra and fluorescence spectroscopy. The divalent metal ions binding induced an obvious conformational change at pH 7 and a pH-sensitive reduction of thermostability in the C-terminal domain. The interactions were further estimated by fluorescence spectroscopy experiments. There are at least two binding sites for divalent metal ions binding to the C-terminal domain of Hv1, either of which is close to His(244) or His(266) residue. The binding of Zn(2+) to the two sites both enhanced the fluorescence of the protein at pH 7, whereas the binding of other divalent metal ions to the two sites all resulted fluorescence quenching. The orders of the strength of divalent metal ions binding to the two sites from strong to weak are both Co(2+), Ca(2+), Ni(2+), Mg(2+), and Mn(2+). The strength of Ca(2+), Co(2+), Mg(2+), Mn(2+) and Ni(2+) binding to the site close to His(244) is stronger than that of these divalent metal ions binding to the site close to His(266).
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Affiliation(s)
- Qing Zhao
- Department of Biophysics, School of Physics Science, Nankai University, 94 Weijin Road, Nankai District, Tianjin, 300071, People's Republic of China
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45
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Zhang S, Wang Y, Li SJ. Lansoprazole induces apoptosis of breast cancer cells through inhibition of intracellular proton extrusion. Biochem Biophys Res Commun 2014; 448:424-9. [PMID: 24802401 DOI: 10.1016/j.bbrc.2014.04.127] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 04/24/2014] [Indexed: 11/29/2022]
Abstract
The increased glycolysis and proton secretion in tumors is proposed to contribute to the proliferation and invasion of cancer cells during the process of tumorigenesis and metastasis. Here, treatment of human breast cancer cells with proton pump inhibitor (PPI) lansoprazole (LPZ) induces cell apoptosis in a dose-dependent manner. In the implantation of the MDA-MB-231 xenografts in nude mice, administration of LPZ significantly inhibits tumorigenesis and induces large-scale apopotosis of tumor cells. LPZ markedly inhibits intracellular proton extrusion, induces an increase in intracellular ATP level, lysosomal alkalinization and accumulation of reactive oxygen species (ROS) in breast cancer cells. The ROS scavenger N-acetyl-l-cysteine (NAC) and diphenyleneiodonium (DPI), a specific pharmacological inhibitor of NADPH oxidases (NOX), significantly abolish LPZ-induced ROS accumulation in breast cancer cells. Our results suggested that LPZ may be used as a new therapeutic drug for breast tumor.
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Affiliation(s)
- Shangrong Zhang
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, PR China
| | - Yifan Wang
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, PR China
| | - Shu Jie Li
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, PR China.
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DeCoursey TE, Hosler J. Philosophy of voltage-gated proton channels. J R Soc Interface 2014; 11:20130799. [PMID: 24352668 PMCID: PMC3899857 DOI: 10.1098/rsif.2013.0799] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/22/2013] [Indexed: 02/02/2023] Open
Abstract
In this review, voltage-gated proton channels are considered from a mainly teleological perspective. Why do proton channels exist? What good are they? Why did they go to such lengths to develop several unique hallmark properties such as extreme selectivity and ΔpH-dependent gating? Why is their current so minuscule? How do they manage to be so selective? What is the basis for our belief that they conduct H(+) and not OH(-)? Why do they exist in many species as dimers when the monomeric form seems to work quite well? It is hoped that pondering these questions will provide an introduction to these channels and a way to logically organize their peculiar properties as well as to understand how they are able to carry out some of their better-established biological functions.
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Affiliation(s)
- Thomas E. DeCoursey
- Department of Molecular Biophysics and Physiology, Rush University, 1750 West Harrison, Chicago, IL 60612, USA
| | - Jonathan Hosler
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, MS 39216, USA
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47
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Andersen AP, Moreira JMA, Pedersen SF. Interactions of ion transporters and channels with cancer cell metabolism and the tumour microenvironment. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130098. [PMID: 24493746 DOI: 10.1098/rstb.2013.0098] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Major changes in intra- and extracellular pH homoeostasis are shared features of most solid tumours. These changes stem in large part from the metabolic shift of most cancer cells towards glycolytic metabolism and other processes associated with net acid production. In combination with oncogenic signalling and impact from factors in the tumour microenvironment, this upregulates acid-extruding plasma membrane transport proteins which maintain intracellular pH normal or even more alkaline compared with that of normal cells, while in turn acidifying the external microenvironment. Mounting evidence strongly indicates that this contributes significantly to cancer development by favouring e.g. cancer cell migration, invasion and chemotherapy resistance. Finally, while still under-explored, it seems likely that non-cancer cells in the tumour microenvironment also exhibit altered pH regulation and that this may contribute to their malignant properties. Thus, the physical tumour microenvironment and the cancer and stromal cells within it undergo important reciprocal interactions which modulate the tumour pH profile, in turn severely impacting on the course of cancer progression. Here, we summarize recent knowledge of tumour metabolism and the tumour microenvironment, placing it in the context of tumour pH regulation, and discuss how interfering with these properties may be exploited clinically.
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Affiliation(s)
- Anne Poder Andersen
- Department of Biology, Faculty of Science, University of Copenhagen, Denmark
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48
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Wang Y, Wu X, Li Q, Zhang S, Li SJ. Human voltage-gated proton channel hv1: a new potential biomarker for diagnosis and prognosis of colorectal cancer. PLoS One 2013; 8:e70550. [PMID: 23940591 PMCID: PMC3734282 DOI: 10.1371/journal.pone.0070550] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 06/19/2013] [Indexed: 11/18/2022] Open
Abstract
Solid tumors exist in a hypoxic microenvironment, and possess high-glycolytic metabolites. To avoid the acidosis, tumor cells must exhibit a dynamic cytosolic pH regulation mechanism(s). The voltage-gated proton channel Hv1 mediates NADPH oxidase function by compensating cellular loss of electrons with protons. Here, we showed for the first time, that Hv1 expression is increased in colorectal tumor tissues and cell lines, associated with poor prognosis. Immunohistochemistry showed that Hv1 is strongly expressed in adenocarcinomas but not or lowly expressed in normal colorectal or hyperplastic polyps. Hv1 expression in colorectal cancer is significantly associated with the tumor size, tumor classification, lymph node status, clinical stage and p53 status. High Hv1 expression is associated significantly with shorter overall and recurrence-free survival. Furthermore, real-time RT-PCR and immunocytochemistry showed that Hv1 is highly expressed in colorectal cancer cell lines, SW620, HT29, LS174T and Colo205, but not in SW480. Inhibitions of Hv1 expression and activity in the highly metastatic SW620 cells by small interfering RNA (siRNA) and Zn2+ respectively, markedly decrease the cell invasion and migration, restraint proton extrusion and the intracellular pH recovery. Our results suggest that Hv1 may be used as a potential biomarker for diagnosis and prognosis of colorectal carcinoma, and a potential target for anticancer drugs in colorectal cancer therapy.
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Affiliation(s)
- Yifan Wang
- Department of Biophysics, School of Physics Science, Nankai University, Tianjin, China
- Department of Pathology, Tonghua Center Hospital, Tonghua, China
| | - Xingye Wu
- Department of Pathology, Tonghua Center Hospital, Tonghua, China
| | - Qiang Li
- Department of Biophysics, School of Physics Science, Nankai University, Tianjin, China
- Department of Pathology, Tonghua Center Hospital, Tonghua, China
| | - Shangrong Zhang
- Department of Biophysics, School of Physics Science, Nankai University, Tianjin, China
- Department of Pathology, Tonghua Center Hospital, Tonghua, China
| | - Shu Jie Li
- Department of Biophysics, School of Physics Science, Nankai University, Tianjin, China
- Department of Pathology, Tonghua Center Hospital, Tonghua, China
- * E-mail:
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49
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Wang Y, Zhang S, Li SJ. Zn2+ induces apoptosis in human highly metastatic SHG-44 glioma cells, through inhibiting activity of the voltage-gated proton channel Hv1. Biochem Biophys Res Commun 2013; 438:312-7. [DOI: 10.1016/j.bbrc.2013.07.067] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 07/17/2013] [Indexed: 11/26/2022]
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50
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DeCoursey TE. Voltage-gated proton channels: molecular biology, physiology, and pathophysiology of the H(V) family. Physiol Rev 2013; 93:599-652. [PMID: 23589829 PMCID: PMC3677779 DOI: 10.1152/physrev.00011.2012] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Voltage-gated proton channels (H(V)) are unique, in part because the ion they conduct is unique. H(V) channels are perfectly selective for protons and have a very small unitary conductance, both arguably manifestations of the extremely low H(+) concentration in physiological solutions. They open with membrane depolarization, but their voltage dependence is strongly regulated by the pH gradient across the membrane (ΔpH), with the result that in most species they normally conduct only outward current. The H(V) channel protein is strikingly similar to the voltage-sensing domain (VSD, the first four membrane-spanning segments) of voltage-gated K(+) and Na(+) channels. In higher species, H(V) channels exist as dimers in which each protomer has its own conduction pathway, yet gating is cooperative. H(V) channels are phylogenetically diverse, distributed from humans to unicellular marine life, and perhaps even plants. Correspondingly, H(V) functions vary widely as well, from promoting calcification in coccolithophores and triggering bioluminescent flashes in dinoflagellates to facilitating killing bacteria, airway pH regulation, basophil histamine release, sperm maturation, and B lymphocyte responses in humans. Recent evidence that hH(V)1 may exacerbate breast cancer metastasis and cerebral damage from ischemic stroke highlights the rapidly expanding recognition of the clinical importance of hH(V)1.
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Affiliation(s)
- Thomas E DeCoursey
- Dept. of Molecular Biophysics and Physiology, Rush University Medical Center HOS-036, 1750 West Harrison, Chicago, IL 60612, USA.
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