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Blažič A, Guinard M, Leskovar T, O'Connor RP, Rems L. Long-term changes in transmembrane voltage after electroporation are governed by the interplay between nonselective leak current and ion channel activation. Bioelectrochemistry 2024; 161:108802. [PMID: 39243733 DOI: 10.1016/j.bioelechem.2024.108802] [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: 06/24/2024] [Revised: 08/14/2024] [Accepted: 08/26/2024] [Indexed: 09/09/2024]
Abstract
Electroporation causes a temporal increase in cell membrane permeability and leads to prolonged changes in transmembrane voltage (TMV) in both excitable and non-excitable cells. However, the mechanisms of these TMV changes remain to be fully elucidated. To this end, we monitored TMV over 30 min after exposing two different cell lines to a single 100 µs electroporation pulse using the FLIPR Membrane Potential dye. In CHO-K1 cells, which express very low levels of endogenous ion channels, membrane depolarization following pulse exposure could be explained by nonselective leak current, which persists until the membrane reseals, enabling the cells to recover their resting TMV. In U-87 MG cells, which express many different ion channels, we unexpectedly observed membrane hyperpolarization following the initial depolarization phase, but only at 33 °C and not at 25 °C. We developed a theoretical model, supported by experiments with ion channel inhibitors, which indicated that hyperpolarization could largely be attributed to the activation of calcium-activated potassium channels. Ion channel activation, coupled with changes in TMV and intracellular calcium, participates in various physiological processes, including cell proliferation, differentiation, migration, and apoptosis. Therefore, our study suggests that ion channels could present a potential target for influencing the biological response after electroporation.
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Affiliation(s)
- Anja Blažič
- University of Ljubljana, Faculty of Electrical Engineering, SI-1000 Ljubljana, Slovenia
| | - Manon Guinard
- University of Ljubljana, Faculty of Electrical Engineering, SI-1000 Ljubljana, Slovenia
| | - Tomaž Leskovar
- University of Ljubljana, Faculty of Electrical Engineering, SI-1000 Ljubljana, Slovenia
| | - Rodney P O'Connor
- Mines Saint-Etienne, Centre CMP, Département BEL, F-13541 Gardanne, France
| | - Lea Rems
- University of Ljubljana, Faculty of Electrical Engineering, SI-1000 Ljubljana, Slovenia.
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2
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Hughes MP, Clarke KSP, Hoque R, Griffiths OV, Kruchek EJ, Johnson MP, Tariq MH, Kohli N, Lewis R, Labeed FH. Label-free, non-contact determination of resting membrane potential using dielectrophoresis. Sci Rep 2024; 14:18477. [PMID: 39122771 PMCID: PMC11316104 DOI: 10.1038/s41598-024-69000-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 07/30/2024] [Indexed: 08/12/2024] Open
Abstract
Measurement of cellular resting membrane potential (RMP) is important in understanding ion channels and their role in regulation of cell function across a wide range of cell types. However, methods available for the measurement of RMP (including patch clamp, microelectrodes, and potential-sensitive fluorophores) are expensive, slow, open to operator bias, and often result in cell destruction. We present non-contact, label-free membrane potential estimation which uses dielectrophoresis to determine the cytoplasm conductivity slope as a function of medium conductivity. By comparing this to patch clamp data available in the literature, we have demonstratet the accuracy of this approach using seven different cell types, including primary suspension cells (red blood cells, platelets), cultured suspension cells (THP-1), primary adherent cells (chondrocytes, human umbilical mesenchymal stem cells), and adherent (HeLa) and suspension (Jurkat) cancer cell lines. Analysis of the effect of ion channel inhibitors suggests the effects of pharmaceutical agents (TEA on HeLa; DMSO and neuraminidase on red blood cells) can also be measured. Comparison with published values of membrane potential suggest that the differences between our estimates and values recorded by patch clamp are accurate to within published margins of error. The method is low-cost, non-destructive, operator-independent and label-free, and has previously been shown to allow cells to be recovered after measurement.
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Affiliation(s)
- Michael Pycraft Hughes
- Department of Biomedical Engineering and Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, UAE.
- Healthcare Engineering Innovation Center, Khalifa University of Science and Technology, Abu Dhabi, UAE.
| | - Krista S P Clarke
- Centre for Biomedical Engineering, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Rashedul Hoque
- Centre for Biomedical Engineering, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Oreoluwa V Griffiths
- Centre for Biomedical Engineering, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Emily J Kruchek
- Centre for Biomedical Engineering, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Matthew P Johnson
- Department of Biomedical Engineering and Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, UAE
| | - Muhammad Hamza Tariq
- Department of Biomedical Engineering and Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, UAE
| | - Nupur Kohli
- Department of Biomedical Engineering and Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, UAE
- Healthcare Engineering Innovation Center, Khalifa University of Science and Technology, Abu Dhabi, UAE
| | - Rebecca Lewis
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Fatima H Labeed
- Department of Biology, United Arab Emirates University, Al Ain, UAE.
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3
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Rühl P, Nair AG, Gawande N, Dehiwalage SNCW, Münster L, Schönherr R, Heinemann SH. An Ultrasensitive Genetically Encoded Voltage Indicator Uncovers the Electrical Activity of Non-Excitable Cells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307938. [PMID: 38526185 PMCID: PMC11132041 DOI: 10.1002/advs.202307938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 02/10/2024] [Indexed: 03/26/2024]
Abstract
Most animal cell types are classified as non-excitable because they do not generate action potentials observed in excitable cells, such as neurons and muscle cells. Thus, resolving voltage signals in non-excitable cells demands sensors with exceptionally high voltage sensitivity. In this study, the ultrabright, ultrasensitive, and calibratable genetically encoded voltage sensor rEstus is developed using structure-guided engineering. rEstus is most sensitive in the resting voltage range of non-excitable cells and offers a 3.6-fold improvement in brightness change for fast voltage spikes over its precursor ASAP3. Using rEstus, it is uncovered that the membrane voltage in several non-excitable cell lines (A375, HEK293T, MCF7) undergoes spontaneous endogenous alterations on a second to millisecond timescale. Correlation analysis of these optically recorded voltage alterations provides a direct, real-time readout of electrical cell-cell coupling, showing that visually connected A375 and HEK293T cells are also largely electrically connected, while MCF7 cells are only weakly coupled. The presented work provides enhanced tools and methods for non-invasive voltage imaging in living cells and demonstrates that spontaneous endogenous membrane voltage alterations are not limited to excitable cells but also occur in a variety of non-excitable cell types.
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Affiliation(s)
- Philipp Rühl
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, D-07745, Jena, Germany
| | - Anagha G Nair
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, D-07745, Jena, Germany
| | - Namrata Gawande
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, D-07745, Jena, Germany
| | - Sassrika N C W Dehiwalage
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, D-07745, Jena, Germany
| | - Lukas Münster
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, D-07745, Jena, Germany
| | - Roland Schönherr
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, D-07745, Jena, Germany
| | - Stefan H Heinemann
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, D-07745, Jena, Germany
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4
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Nordström T, Andersson LC, Åkerman KEO. Role of hyperpolarization-activated cyclic nucleotide-gated channel HCN2 in embryonic neural stem cell proliferation and differentiation. Neurochem Int 2022; 159:105387. [PMID: 35835292 DOI: 10.1016/j.neuint.2022.105387] [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: 03/14/2022] [Revised: 06/06/2022] [Accepted: 07/03/2022] [Indexed: 10/17/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated channels (HCN channels) are involved in spontaneous activity in many electrically active cell types such as cardiomyocytes and neurons. In this study, the role of HCN channels in proliferation and migration of Nestin and Sox2 expressing embryonic neural progenitor cells (NPC) originating from the subventricular zone (SVZ) was examined. Immunostaining and PCR data showed that the HCN2 subtype was highly expressed in these cells. Patch clamp recordings revealed a hyperpolarization-activated current, which was sensitive to inhibitors of HCN channels. Using the fluorescence dye bis-(1,3-dibutylbarbituric acid)-trimethineoxonol (DiBAC(4)(3)) we found that a prompt reduction of the extracellular K+ concentration, or exposing the cells to acute hypoxia, induced an instant hyperpolarization in the whole cell population. Recovery from low K+ induced hyperpolarization after extracellular calcium removal, or by re-oxygenation of hypoxic cells, was sensitive to ZD7288, a HCN channel inhibitor. Treatment of neurosphere cultures from the SVZ with ZD7288 caused a significant and reversible inhibition of neurosphere formation from single cells indicating that proliferation of progenitor cells was reduced. Furthermore, the migration of neuronal cells from neurospheres was considerably retarded in the presence of ZD7288. The results suggest that HCN2 channels are involved in controlling the proliferation of NPC and that HCN2 channel-induced spontaneous electrical activity may trigger the motility response of neurosphere-derived neurons in concert with other ion channels. Furthermore, the response to hypoxia suggests that HCN2 channels may trigger the chemotactic response of NPC to ischemic brain regions seen in many studies.
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Affiliation(s)
- Tommy Nordström
- Faculty of Medicine, Medicum, Division of Physiology, P.O. Box 63, University of Helsinki, FIN-00014, Helsinki, Finland.
| | - Leif C Andersson
- Department of Pathology, Haartmaninkatu 3 (PB 21), 00014 University of Helsinki, Helsinki, Finland
| | - Karl E O Åkerman
- Faculty of Medicine, Medicum, Division of Physiology, P.O. Box 63, University of Helsinki, FIN-00014, Helsinki, Finland
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5
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Kim BB, Wu H, Hao YA, Pan M, Chavarha M, Zhao Y, Westberg M, St-Pierre F, Wu JC, Lin MZ. A red fluorescent protein with improved monomericity enables ratiometric voltage imaging with ASAP3. Sci Rep 2022; 12:3678. [PMID: 35256624 PMCID: PMC8901740 DOI: 10.1038/s41598-022-07313-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 01/18/2022] [Indexed: 02/07/2023] Open
Abstract
A ratiometric genetically encoded voltage indicator (GEVI) would be desirable for tracking transmembrane voltage changes in the presence of sample motion. We performed combinatorial multi-site mutagenesis on a cyan-excitable red fluorescent protein to create the bright and monomeric mCyRFP3, which proved to be uniquely non-perturbing when fused to the GEVI ASAP3. The green/red ratio from ASAP3-mCyRFP3 (ASAP3-R3) reported voltage while correcting for motion artifacts, allowing the visualization of membrane voltage changes in contracting cardiomyocytes and throughout the cell cycle of motile cells.
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Affiliation(s)
- Benjamin B Kim
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Haodi Wu
- Stanford Cardiovascular Institute, Stanford University, Stanford, USA
- Department of Medicine, Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yukun A Hao
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Michael Pan
- Department of Neurobiology, Stanford University, Stanford, CA, USA
| | - Mariya Chavarha
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Yufeng Zhao
- Department of Neurobiology, Stanford University, Stanford, CA, USA
| | - Michael Westberg
- Department of Neurobiology, Stanford University, Stanford, CA, USA
- Department of Chemistry, Aarhus University, Aarhus, Denmark
| | | | - Joseph C Wu
- Stanford Cardiovascular Institute, Stanford University, Stanford, USA
| | - Michael Z Lin
- Department of Bioengineering, Stanford University, Stanford, CA, USA.
- Department of Neurobiology, Stanford University, Stanford, CA, USA.
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6
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George LF, Bates EA. Mechanisms Underlying Influence of Bioelectricity in Development. Front Cell Dev Biol 2022; 10:772230. [PMID: 35237593 PMCID: PMC8883286 DOI: 10.3389/fcell.2022.772230] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/07/2022] [Indexed: 12/25/2022] Open
Abstract
To execute the intricate process of development, cells coordinate across tissues and organs to determine where each cell divides and differentiates. This coordination requires complex communication between cells. Growing evidence suggests that bioelectrical signals controlled via ion channels contribute to cell communication during development. Ion channels collectively regulate the transmembrane potential of cells, and their function plays a conserved role in the development of organisms from flies to humans. Spontaneous calcium oscillations can be found in nearly every cell type and tissue, and disruption of these oscillations leads to defects in development. However, the mechanism by which bioelectricity regulates development is still unclear. Ion channels play essential roles in the processes of cell death, proliferation, migration, and in each of the major canonical developmental signaling pathways. Previous reviews focus on evidence for one potential mechanism by which bioelectricity affects morphogenesis, but there is evidence that supports multiple different mechanisms which are not mutually exclusive. Evidence supports bioelectricity contributing to development through multiple different mechanisms. Here, we review evidence for the importance of bioelectricity in morphogenesis and provide a comprehensive review of the evidence for several potential mechanisms by which ion channels may act in developmental processes.
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Affiliation(s)
- Laura Faith George
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Emily Anne Bates
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
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7
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Bonzanni M, Payne SL, Adelfio M, Kaplan DL, Levin M, Oudin MJ. Defined extracellular ionic solutions to study and manipulate the cellular resting membrane potential. Biol Open 2020; 9:bio048553. [PMID: 31852666 PMCID: PMC6994931 DOI: 10.1242/bio.048553] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 12/04/2019] [Indexed: 12/19/2022] Open
Abstract
All cells possess an electric potential across their plasma membranes and can generate and receive bioelectric signals. The cellular resting membrane potential (RMP) can regulate cell proliferation, differentiation and apoptosis. Current approaches to measure the RMP rely on patch clamping, which is technically challenging, low-throughput and not widely available. It is therefore critical to develop simple strategies to measure, manipulate and characterize the RMP. Here, we present a simple methodology to study the RMP of non-excitable cells and characterize the contribution of individual ions to the RMP using a voltage-sensitive dye. We define protocols using extracellular solutions in which permeable ions (Na+, Cl- and K+) are substituted with non-permeable ions [N-Methyl-D-glucamine (NMDG), gluconate, choline, SO42-]. The resulting RMP modifications were assessed with both patch clamp and a voltage sensitive dye. Using an epithelial and cancer cell line, we demonstrate that the proposed ionic solutions can selectively modify the RMP and help determine the relative contribution of ionic species in setting the RMP. The proposed method is simple and reproducible and will make the study of bioelectricity more readily available to the cell biology community.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Mattia Bonzanni
- Department of Biomedical Engineering, Tufts University, Medford, 02155 MA, USA
- Allen Discovery Center, Tufts University, Medford, 02155 MA, USA
| | - Samantha L Payne
- Department of Biomedical Engineering, Tufts University, Medford, 02155 MA, USA
| | - Miryam Adelfio
- Department of Biomedical Engineering, Tufts University, Medford, 02155 MA, USA
| | - David L Kaplan
- Department of Biomedical Engineering, Tufts University, Medford, 02155 MA, USA
- Allen Discovery Center, Tufts University, Medford, 02155 MA, USA
| | - Michael Levin
- Allen Discovery Center, Tufts University, Medford, 02155 MA, USA
| | - Madeleine J Oudin
- Department of Biomedical Engineering, Tufts University, Medford, 02155 MA, USA
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8
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Leslie TK, James AD, Zaccagna F, Grist JT, Deen S, Kennerley A, Riemer F, Kaggie JD, Gallagher FA, Gilbert FJ, Brackenbury WJ. Sodium homeostasis in the tumour microenvironment. Biochim Biophys Acta Rev Cancer 2019; 1872:188304. [PMID: 31348974 PMCID: PMC7115894 DOI: 10.1016/j.bbcan.2019.07.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 12/17/2022]
Abstract
The concentration of sodium ions (Na+) is raised in solid tumours and can be measured at the cellular, tissue and patient levels. At the cellular level, the Na+ gradient across the membrane powers the transport of H+ ions and essential nutrients for normal activity. The maintenance of the Na+ gradient requires a large proportion of the cell's ATP. Na+ is a major contributor to the osmolarity of the tumour microenvironment, which affects cell volume and metabolism as well as immune function. Here, we review evidence indicating that Na+ handling is altered in tumours, explore our current understanding of the mechanisms that may underlie these alterations and consider the potential consequences for cancer progression. Dysregulated Na+ balance in tumours may open opportunities for new imaging biomarkers and re-purposing of drugs for treatment.
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Affiliation(s)
- Theresa K Leslie
- Department of Biology, University of York, Heslington, York YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK
| | - Andrew D James
- Department of Biology, University of York, Heslington, York YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK
| | - Fulvio Zaccagna
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - James T Grist
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Surrin Deen
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Aneurin Kennerley
- York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK; Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | - Frank Riemer
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Joshua D Kaggie
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Ferdia A Gallagher
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Fiona J Gilbert
- Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - William J Brackenbury
- Department of Biology, University of York, Heslington, York YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK.
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9
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Herrmann A, Nagao T, Zhang C, Lahtz C, Li YJ, Yue C, Mülfarth R, Yu H. An effective cell-penetrating antibody delivery platform. JCI Insight 2019; 4:127474. [PMID: 31341104 DOI: 10.1172/jci.insight.127474] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 05/31/2019] [Indexed: 12/25/2022] Open
Abstract
Despite their well-recognized success in the clinic, antibodies generally do not penetrate cellular membranes to target intracellular molecules, many of which underlie incurable diseases. Here we show that covalently conjugating phosphorothioated DNA oligonucleotides to antibodies enabled their efficient cellular internalization. Antibody cell penetration was partially mediated by membrane potential alteration. Moreover, without an antigen to bind, intracellular levels of the modified antibodies underwent cellular clearance, which involved efflux and lysosomal degradation, enabling detection of intended intracellular molecules as tested in fibroblasts, tumor cells, and T cells. This target-dependent cellular retention of modified antibodies extended to in vivo studies. Both local and systemic administrations of low doses of modified antibodies effectively inhibited intracellular targets, such as transcription factors Myc, interferon regulatory factor 4, and tyrosine-protein kinase SRC, and expression of their downstream genes in tumors, resulting in tumor cell apoptosis and tumor growth inhibition. This simple modification enables the use of antibodies to detect and modulate intracellular molecules in both cultured living cells and in whole animals, forming the foundation for a new paradigm for antibody-based research, diagnostics, and therapeutics.
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Affiliation(s)
- Andreas Herrmann
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA.,LACell at Sorrento Therapeutics, San Diego, California, USA
| | - Toshikage Nagao
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Chunyan Zhang
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Christoph Lahtz
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA.,LACell at Sorrento Therapeutics, San Diego, California, USA
| | - Yi-Jia Li
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Chanyu Yue
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA.,LACell at Sorrento Therapeutics, San Diego, California, USA
| | - Ronja Mülfarth
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Hua Yu
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
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10
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Abstract
Modern stem cell research has mainly focused on protein expression and transcriptional networks. However, transmembrane voltage gradients generated by ion channels and transporters have demonstrated to be powerful regulators of cellular processes. These physiological cues exert influence on cell behaviors ranging from differentiation and proliferation to migration and polarity. Bioelectric signaling is a fundamental element of living systems and an untapped reservoir for new discoveries. Dissecting these mechanisms will allow for novel methods of controlling cell fate and open up new opportunities in biomedicine. This review focuses on the role of ion channels and the resting membrane potential in the proliferation and differentiation of skeletal muscle progenitor cells. In addition, findings relevant to this topic are presented and potential implications for tissue engineering and regenerative medicine are discussed.
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Affiliation(s)
- Colin Fennelly
- Department of Neuroscience, Novartis Institutes for BioMedical Research, Inc., Cambridge, Massachusetts
| | - Shay Soker
- Wake Forest Institute for Regenerative Medicine, Winston-Salem, North Carolina
- Wake Forest School of Medicine, Winston-Salem, North Carolina
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11
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Denz M, Chiantia S, Herrmann A, Mueller P, Korte T, Schwarzer R. Cell cycle dependent changes in the plasma membrane organization of mammalian cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:350-359. [DOI: 10.1016/j.bbamem.2016.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 11/24/2016] [Accepted: 12/14/2016] [Indexed: 11/16/2022]
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12
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Sustained Depolarization of the Resting Membrane Potential Regulates Muscle Progenitor Cell Growth and Maintains Stem Cell Properties In Vitro. Stem Cell Rev Rep 2016; 12:634-644. [DOI: 10.1007/s12015-016-9687-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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13
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Abstract
Ion channels have emerged as regulators of developmental processes. In model organisms and in people with mutations in ion channels, disruption of ion channel function can affect cell proliferation, cell migration, and craniofacial and limb patterning. Alterations of ion channel function affect morphogenesis in fish, frogs, mammals, and flies, demonstrating that ion channels have conserved roles in developmental processes. One model suggests that ion channels affect proliferation and migration through changes in cell volume. However, ion channels have not explicitly been placed in canonical developmental signaling cascades until recently. This review gives examples of ion channels that influence developmental processes, offers a potential underlying molecular mechanism involving bone morphogenetic protein (BMP) signaling, and finally explores exciting possibilities for manipulating ion channels to influence cell fate for regenerative medicine and to impact disease.
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Affiliation(s)
- Emily Bates
- Department of Pediatrics, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado 80045;
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14
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Rao VR, Perez-Neut M, Kaja S, Gentile S. Voltage-gated ion channels in cancer cell proliferation. Cancers (Basel) 2015; 7:849-75. [PMID: 26010603 PMCID: PMC4491688 DOI: 10.3390/cancers7020813] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/12/2015] [Indexed: 12/22/2022] Open
Abstract
Changes of the electrical charges across the surface cell membrane are absolutely necessary to maintain cellular homeostasis in physiological as well as in pathological conditions. The opening of ion channels alter the charge distribution across the surface membrane as they allow the diffusion of ions such as K+, Ca++, Cl.
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Affiliation(s)
- Vidhya R Rao
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago 2160 S. 1s tAve, Maywood, IL 60153, USA.
| | - Mathew Perez-Neut
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago 2160 S. 1s tAve, Maywood, IL 60153, USA.
| | - Simon Kaja
- Department of Ophthalmology and Vision Research Center, School of Medicine, University of Missouri-Kansas City, 2411 Holmes St., Kansas City, MO 64108, USA.
| | - Saverio Gentile
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago 2160 S. 1s tAve, Maywood, IL 60153, USA.
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15
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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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Lan JY, Williams C, Levin M, Black LD. Depolarization of Cellular Resting Membrane Potential Promotes Neonatal Cardiomyocyte Proliferation In Vitro. Cell Mol Bioeng 2014; 7:432-445. [PMID: 25295125 DOI: 10.1007/s12195-014-0346-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Cardiomyocytes (CMs) undergo a rapid transition from hyperplastic to hypertrophic growth soon after birth, which is a major challenge to the development of engineered cardiac tissue for pediatric patients. Resting membrane potential (Vmem) has been shown to play an important role in cell differentiation and proliferation during development. We hypothesized that depolarization of neonatal CMs would stimulate or maintain CM proliferation in vitro. To test our hypothesis, we isolated postnatal day 3 neonatal rat CMs and subjected them to sustained depolarization via the addition of potassium gluconate or Ouabain to the culture medium. Cell density and CM percentage measurements demonstrated an increase in mitotic CMs along with a ~2 fold increase in CM numbers with depolarization. In addition, depolarization led to an increase in cells in G2 and S phase, indicating increased proliferation, as measured by flow cytometry. Surprisingly depolarization of Vmem with either treatment led to inhibition of proliferation in cardiac fibroblasts. This effect is abrogated when the study was carried out on postnatal day 7 neonatal CMs, which are less proliferative, indicating that the likely mechanism of depolarization is the maintenance of the proliferating CM population. In summary, our findings suggest that depolarization maintains postnatal CM proliferation and may be a novel approach to encourage growth of engineered tissue and cardiac regeneration in pediatric patients.
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Affiliation(s)
- Jen-Yu Lan
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155 USA
| | - Corin Williams
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155 USA
| | - Michael Levin
- Department of Biology, Tufts University, Medford, MA 02155 USA ; Center for Regenerative and Developmental Biology, Tufts University, Medford, MA 02155 USA
| | - Lauren Deems Black
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155 USA ; Cellular, Molecular and Developmental Biology Program, Sackler Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111 USA
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17
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Urrego D, Tomczak AP, Zahed F, Stühmer W, Pardo LA. Potassium channels in cell cycle and cell proliferation. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130094. [PMID: 24493742 PMCID: PMC3917348 DOI: 10.1098/rstb.2013.0094] [Citation(s) in RCA: 269] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Normal cell-cycle progression is a crucial task for every multicellular organism, as it determines body size and shape, tissue renewal and senescence, and is also crucial for reproduction. On the other hand, dysregulation of the cell-cycle progression leading to uncontrolled cell proliferation is the hallmark of cancer. Therefore, it is not surprising that it is a tightly regulated process, with multifaceted and very complex control mechanisms. It is now well established that one of those mechanisms relies on ion channels, and in many cases specifically on potassium channels. Here, we summarize the possible mechanisms underlying the importance of potassium channels in cell-cycle control and briefly review some of the identified channels that illustrate the multiple ways in which this group of proteins can influence cell proliferation and modulate cell-cycle progression.
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Affiliation(s)
- Diana Urrego
- Oncophysiology Group, Max Planck Institute of Experimental Medicine, , Hermann-Rein-Strasse 3, Göttingen 37075, Germany
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18
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Yang M, Brackenbury WJ. Membrane potential and cancer progression. Front Physiol 2013; 4:185. [PMID: 23882223 PMCID: PMC3713347 DOI: 10.3389/fphys.2013.00185] [Citation(s) in RCA: 362] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 06/28/2013] [Indexed: 12/27/2022] Open
Abstract
Membrane potential (Vm), the voltage across the plasma membrane, arises because of the presence of different ion channels/transporters with specific ion selectivity and permeability. Vm is a key biophysical signal in non-excitable cells, modulating important cellular activities, such as proliferation and differentiation. Therefore, the multiplicities of various ion channels/transporters expressed on different cells are finely tuned in order to regulate the Vm. It is well-established that cancer cells possess distinct bioelectrical properties. Notably, electrophysiological analyses in many cancer cell types have revealed a depolarized Vm that favors cell proliferation. Ion channels/transporters control cell volume and migration, and emerging data also suggest that the level of Vm has functional roles in cancer cell migration. In addition, hyperpolarization is necessary for stem cell differentiation. For example, both osteogenesis and adipogenesis are hindered in human mesenchymal stem cells (hMSCs) under depolarizing conditions. Therefore, in the context of cancer, membrane depolarization might be important for the emergence and maintenance of cancer stem cells (CSCs), giving rise to sustained tumor growth. This review aims to provide a broad understanding of the Vm as a bioelectrical signal in cancer cells by examining several key types of ion channels that contribute to its regulation. The mechanisms by which Vm regulates cancer cell proliferation, migration, and differentiation will be discussed. In the long term, Vm might be a valuable clinical marker for tumor detection with prognostic value, and could even be artificially modified in order to inhibit tumor growth and metastasis.
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Affiliation(s)
- Ming Yang
- Department of Biology, University of York York, UK
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19
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Pichardo S, Togtema M, Jackson R, Zehbe I, Curiel L. Influence of cell line and cell cycle phase on sonoporation transfection efficiency in cervical carcinoma cells under the same physical conditions. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2013; 60:432-435. [PMID: 23357919 DOI: 10.1109/tuffc.2013.2581] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Using cervical-carcinoma-derived cells as a model, the present study investigates the effects cell line and cell cycle phase have on sonoporation transfection efficiency under the same physical conditions. A plasmid expressing green fluorescent protein (GFP) was used to measure transfection efficiency. To evaluate the effect of cell type, CaSki, HeLa, and SiHa cells were sonoporated using an acoustic pressure of 1 MPa for 30 s with a duty cycle of 4.8% in the presence of the GFP plasmid. To study the effect of cell cycle phase, SiHa cells were synchronized at S-phase using a double thymidine block and sonoporated at different time points after the block. Contrast agent microbubbles were used at a 0.33% volume concentration. Results indicated that both cell line and cell cycle phase impact the transfection efficiency obtained with sonoporation.
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Li W, Zhang SL, Wang N, Zhang BB, Li M. Blockade of T-type Ca(2+) channels inhibits human ovarian cancer cell proliferation. Cancer Invest 2011; 29:339-46. [PMID: 21438841 DOI: 10.3109/07357907.2011.568565] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Regulation of Ca(2+) channels has been implicated in the progression of tumor cells. We report here that T-type Ca(2+) channel expression in human ovarian cancer tissues is greatly increased compared to normal ovarian tissues. Blockade of T-type Ca(2+) channel with NNC 55-0396, mibefradil, or by specifically knocking down the expression of these proteins with siRNA-Ca(v)3.1/3.2 suppressed the proliferation of two ovarian cancer cell lines and increased G0/G1 phase distribution in the cell cycle. Furthermore, NNC 55-0396 slowed ovarian cancer formation in nude mice. Therefore the function of T-type Ca(2+) channels is important for the proliferation of human ovarian cancer cells.
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Affiliation(s)
- Wei Li
- Department of Gynecology, Shengjing Hospital, China Medical University, Shenyang, China
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21
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Mahrour N, Pologea-Moraru R, Moisescu MG, Orlowski S, Levêque P, Mir LM. In vitro increase of the fluid-phase endocytosis induced by pulsed radiofrequency electromagnetic fields: importance of the electric field component. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1668:126-37. [PMID: 15670738 DOI: 10.1016/j.bbamem.2004.11.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2003] [Revised: 11/23/2004] [Accepted: 11/24/2004] [Indexed: 10/26/2022]
Abstract
Nowadays, due to the wide use of mobile phones, the possible biological effects of electromagnetic fields (EMF) become a public health general concern. Despite intensive research, there are no widely accepted theories about the interactions between EMFs and living cells, and the experimental data are often controversial. We examined the effects of mobile phones EMF (envelope frequency of 217 Hz, carrier frequency of 900 MHz and pulse duration of 580 micros) or its pure, low-frequency pulsed electric field component on fluid-phase endocytosis. In both cases, with exposures exceeding 10 min, an increase of the fluid-phase endocytosis rate was observed ( approximately 1.5-fold), on three different cell types. This increase is an all-or-nothing type of response that is occurring for threshold values comprised between 1.3 and 2.6 W/kg for the delivered EMF powers and between 1.1 and 1.5 V/cm for the electric fields intensities depending upon the cell type. The electric component of these EMFs is shown to be responsible for the observed increase. Variations of frequency or pulse duration of the electric pulses are shown to be without effect. Thus, EMF, via their electrical component, can perturb one of the most fundamental physiological functions of the cells-endocytosis.
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Affiliation(s)
- Nawel Mahrour
- Laboratoire de Vectorologie et Transfert de Gènes, UMR 8121 CNRS, Institut Gustave-Roussy, 39 rue Camille Desmoulins, 94805 Villejuif Cedex, France
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22
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Golzio M, Teissié J, Rols MP. Cell synchronization effect on mammalian cell permeabilization and gene delivery by electric field. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1563:23-8. [PMID: 12007621 DOI: 10.1016/s0005-2736(02)00369-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Electropermeabilization is a promising nonviral method for gene therapy. However, despite the fact that it is widely used to transfer genes into living cells, the steps that limit DNA transfer remain to be determined. Here, we report the effect of cell synchronization on membrane permeabilization and gene delivery by electric fields. Chinese hamster ovary (CHO) cells were synchronized by aphidicolin or butyrate treatment. Electro-mediated transfection of these cells was evaluated under electric field conditions leading to the same level of membrane permeabilization. Aphidicolin cell synchronization in G2/M phase leads to a slight increase in plasma membrane permeabilization but to a three-fold increase in percentage of transfected cells and to an eight-fold increase in gene expression. This increase in cell transfection is specifically due to the G2/M synchronization process. Indeed, cell synchronization in G1 phase by sodium butyrate has no effect on cell permeabilization and transfection. Our results suggest that the enhanced transfection level in G2/M phase is not simply due to enhanced permeabilization, but reinforce the statement that the melting of the nuclear membrane facilitates direct access of plasmid DNA to the nucleus.
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Affiliation(s)
- Muriel Golzio
- Institut de Pharmacologie et de Biologie Structurale du CNRS UMR 5089, 205, route de Narbonne, 31077 Cedex Toulouse, France
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23
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Pavlin M, Pavselj N, Miklavcic D. Dependence of induced transmembrane potential on cell density, arrangement, and cell position inside a cell system. IEEE Trans Biomed Eng 2002; 49:605-12. [PMID: 12046706 DOI: 10.1109/tbme.2002.1001975] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A nonuniform transmembrane potential (TMP) is induced on a cell membrane exposed to external electric field. If the induced TMP is above the threshold value, cell membrane becomes permeabilized in a reversible process called electropermeabilization. Studying electric potential distribution on the cell membrane gives us an insight into the effects of the electric field on cells and tissues. Since cells are always surrounded by other cells, we studied how their interactions influence the induced TMP. In the first part of our study, we studied dependence of potential distribution on cell arrangement and density in infinite cell suspensions where cells were organized into simple-cubic, body-centered cubic, and face-centered cubic lattice. In the second part of the study, we examined how induced TMP on a cell membrane is dependent on its position inside a three-dimensional cell cluster. Finally, the results for cells inside the cluster were compared to those in infinite lattice. We used numerical analysis for the study, specifically the finite-element method (FEM). The results for infinite cell suspensions show that the induced TMP depends on both: cell volume fraction and cell arrangement. We established from the results for finite volume cell clusters and layers, that there is no radial dependence of induced TMP for cells inside the cluster.
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Affiliation(s)
- Mojca Pavlin
- University of Ljubljana, Faculty of Electrical Engineering, Slovenia
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24
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Beech JA. Bioelectric potential gradients may initiate cell cycling: ELF and zeta potential gradients may mimic this effect. Bioelectromagnetics 2000; 18:341-8. [PMID: 9209715 DOI: 10.1002/(sici)1521-186x(1997)18:5<341::aid-bem1>3.0.co;2-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
When a number of experimental studies in bioelectromagnetics were reviewed, those in which weak, exogenous extremely low frequency (ELF) fields were applied in fixed juxtaposition to their target tissues, were found to initiate mitogenesis or mitogenesis-related signals more successfully than when the target tissue moved freely during the irradiation. It is suggested that ELF fields in fixed juxtaposition to their target tissue and implanted foreign bodies or endogenous tissues with a significant zeta potential, mimic bioelectric fields generated at wounds. When the potential is high enough, they assist healing by moving cells into the wound and stimulating quiescent cells at the wound margin to cycle. Electrophoresis may help the initial migration of cells into the wound to form a clot, and migration of fibroblasts and epithelial cells from the wound margin. When exposed for a long time in a fixed juxtaposition to a potential gradient too weak to show in situ microelectrophoresis along the cell membrane surface, surface particles may coalesce to form microclusters, where like-charged surface particles are in close proximity, and growth factor receptor oligomerization and other cycle-initiating reactions are facilitated.
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25
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Pellegrin P, Menard C, Mery J, Lory P, Charnet P, Bennes R. Cell cycle dependent toxicity of an amphiphilic synthetic peptide. FEBS Lett 1997; 418:101-5. [PMID: 9414104 DOI: 10.1016/s0014-5793(97)01339-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The cytotoxic properties of an amphiphilic synthetic peptide are presented. Comparative analysis of proliferating, differentiated and confluent H9C2 adherent cells and L1210 cells in suspension shows a correlation between toxicity and cell stage (proliferating cells). Electrophysiological measurements on Xenopus laevis oocytes bathed in the peptide also demonstrated the induction of cationic currents, which is voltage and phosphate dependent. These results allow us to hypothesize that the observed toxicity is related to membrane hyperpolarization of proliferating cells at the G1/S cell cycle phase transition.
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Affiliation(s)
- P Pellegrin
- Centre de Recherche de Biochimie Macromoléculaire, Montpellier, France.
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26
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Kolomytkin OV, Marino AA, Sadasivan KK, Wolf RE, Albright JA. Interleukin-1 beta switches electrophysiological states of synovial fibroblasts. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:R1822-8. [PMID: 9374828 DOI: 10.1152/ajpregu.1997.273.5.r1822] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The role of electro-physiological events in signal transduction of interleukin-1 beta (IL-1 beta) was investigated in rabbit synovial fibroblasts using the perforated-patch method. Aggregated synovial fibroblasts using the perforated-patch method. Aggregated synovial fibroblasts occurred in two different electrophysiological states having membrane potentials (Vm) of -63 +/- 4 (n = 71) and -27 +/- 10 mV (n = 55) (high and low Vm, respectively). IL-1 beta affected the cells with high Vm; it switched the state of the cell from high to low Vm. This effect was strongly dependent on the external potential applied to the cell membrane. Low Vm (-30 mV) alone without IL-1 beta did not switch the state of the cells. Thus a synergistic effect involving the cytokine and cell Vm in switching the electrophysiological state of the cell was shown, indicating that electrophysiological changes are involved in signal transduction. Gap junctions between aggregated cells were necessary for the cells to have a high Vm and to respond to IL-1 beta. Gap junction resistance between adjacent cells was estimated as 300 +/- 100 M omega. Our findings suggest that the electrophysiological behavior of synovial fibroblasts is tightly connected to a signaling or intracellular mediator system that is triggered by IL-1 beta.
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Affiliation(s)
- O V Kolomytkin
- Department of Orthopaedic Surgery, Louisiana State University Medical Center, Shreveport 71130-3932, USA
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27
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Fukuda M, Shimizu K, Okamoto N, Arimura T, Ohta T, Yamaguchi S, Faupel ML. Prospective evaluation of skin surface electropotentials in Japanese patients with suspicious breast lesions. Jpn J Cancer Res 1996; 87:1092-6. [PMID: 8957069 PMCID: PMC5920994 DOI: 10.1111/j.1349-7006.1996.tb03115.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The biofield breast examination (BBE) is a new, noninvasive and cost-effective method for diagnosing breast lesions currently undergoing multicenter evaluation in the USA and Europe. The test analyzes subtle differences in electrical potential caused by dysregulated epithelial proliferation. This report summarizes a prospective evaluation of BBE in a population of 101 patients with suspicious breast lesions scheduled either for open surgical biopsy or fine needle aspiration biopsy. Of the 101 patients included in the study, 49 were found to have a breast malignancy and 52 were found to have a benign breast lesion. BBE correctly identified 44 of 49 biopsy-proven cancers (sensitivity=90%) and correctly indicated no cancer in 31 of 52 biopsy-proven benign cases (specificity=60%). Sensitivity increased to 95% for cancers less than 2.5 cm in size. These results indicate that BBE may be an effective adjunctive test to help to resolve abnormalities discovered by physical examination or other screening methods.
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Affiliation(s)
- M Fukuda
- First Department of Surgery, St. Marianna University School of Medicine, Kawasaki, Japan
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28
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Sacchini V. Report of the European School of Oncology task force on Electropotentials in the Clinical Assessment of Neoplasia. Breast 1996. [DOI: 10.1016/s0960-9776(96)90027-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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29
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Wonderlin WF, Woodfork KA, Strobl JS. Changes in membrane potential during the progression of MCF-7 human mammary tumor cells through the cell cycle. J Cell Physiol 1995; 165:177-85. [PMID: 7559799 DOI: 10.1002/jcp.1041650121] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We previously reported that MCF-7 cells were arrested in the G0/G1 phase of the cell cycle by agents known to block the activity of ATP-sensitive potassium channels (Woodfork et al., 1995, J. Cell Physiol. 162:163-171). The goal of our current study was to determine if MCF-7 cells undergo changes in membrane potential during the cell cycle that might be linked to changes in K permeability. The resting membrane potentials of unsynchronized MCF-7 cells during exponential growth phase were measured using sharp glass microelectrodes, and they ranged from -58.6 mV to -2.7 mV. The distribution of membrane potentials was best fitted by the sum of four Gaussian distributions with means of -9.0 mV, -17.4 mV, -24.6 mV, and -40.4 mV. These membrane potential groups were designated D (depolarized), ID (intermediate depolarized), IH (intermediate hyperpolarized), and H (hyperpolarized), respectively. The membrane potential was sensitive to the substitution of external K and Na but not Cl. The K:Na permeability ratio increased in proportion to the negativity of the membrane potential. MCF-7 cells pharmacologically arrested in G0/G1 phase were depolarized compared to control, with cells shifted from the H and IH groups to the D group. Tamoxifen-arrested cells chased from G0/G1 into S phase by the addition of mitogenic concentrations of 17 beta-estradiol were not depolarized, and these cells were shifted from the D group back to the IH and H groups. We conclude that MCF-7 cells hyperpolarize during passage through G0/G1 and into S phase, and this hyperpolarization probably results from an increase in the relative permeability of the plasma membrane to K.
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Affiliation(s)
- W F Wonderlin
- Department of Pharmacology and Toxicology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown 26506, USA
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30
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Woodfork KA, Wonderlin WF, Peterson VA, Strobl JS. Inhibition of ATP-sensitive potassium channels causes reversible cell-cycle arrest of human breast cancer cells in tissue culture. J Cell Physiol 1995; 162:163-71. [PMID: 7822427 DOI: 10.1002/jcp.1041620202] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The purpose of this study was to determine if potassium channel activity is required for the proliferation of MCF-7 human mammary carcinoma cells. We examined the sensitivities of proliferation and progress through the cell cycle to each of nine potassium channel antagonists. Five of the potassium channel antagonists produced a concentration-dependent inhibition of cell proliferation with no evidence of cytotoxicity following a 3-day or 5-day exposure to drug. The IC50 values for these five drugs, quinidine (25 microM), glibenclamide (50 microM), linogliride (770 microM), 4-aminopyridine (1.6 mM), and tetraethylammonium (5.8 mM) were estimated from their respective concentration-response curves. Four other potassium channel blockers were tested at supra-maximal channel blocking concentrations, including charybdotoxin (200 nM), iberiotoxin (100 nM), margatoxin (10 nM), and apamin (500 nM), and they had no effect on MCF-7 cell proliferation, viability, or cell cycle distribution. Of the five drugs that inhibited proliferation, only quinidine, glibenclamide, and linogliride also affected the cell cycle distribution. Cell populations exposed to each of these drugs for 3 days showed a statistically significant accumulation in G0/G1 phase and a significant proportional reduction in S phase and G2/M phase cells. The inhibition of cell proliferation correlated significantly with the extent of cell accumulation in G0/G1 phase and the threshold concentrations for inhibition of growth and G0/G1 arrest were similar. The G0/G1 arrest produced by quinidine and glibenclamide were reversed by removing the drug, and cells released from arrest entered S phase synchronously with a lag period of approximately 24 hours. Based on the differential sensitivity of cell proliferation and cell cycle progression to the nine potassium channel antagonists, we conclude that inhibition of ATP-sensitive potassium channels in these human mammary carcinoma cells, reversibly arrests the cells in the G0/G1 phase of the cell cycle, resulting in an inhibition of cell proliferation.
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Affiliation(s)
- K A Woodfork
- Department of Pharmacology and Toxicology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown 26506
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31
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Takahashi A, Yamaguchi H, Miyamoto H. Change in K+ current of HeLa cells with progression of the cell cycle studied by patch-clamp technique. THE AMERICAN JOURNAL OF PHYSIOLOGY 1993; 265:C328-36. [PMID: 8368262 DOI: 10.1152/ajpcell.1993.265.2.c328] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The K+ channel of HeLa S3 cells in metaphase was analyzed by inside-out and whole cell patch-clamp techniques. The channel had the characteristics of strong inward rectification, small conductance (22 pS at -100 mV), and dependence on intracellular Ca2+. We investigated the cell cycle dependency of the channel, using cells synchronized by harvesting them at the mitotic stage. The cell capacitance increased gradually with increases in the cell volume toward the S phase. The inward K+ currents through the channel at fixed membrane potentials were highest in early G1 and then decreased with time to a minimum in the S phase, increasing again in the M phase. The permeabilities at fixed membrane potentials were also highest in early G1, decreased to minima in the S phase, and increased again toward the next mitosis. In contrast, mean amplitude and the open probability of the single channel at a fixed membrane potential (-60 mV) did not change significantly during the cell cycle. Therefore the capacitance increases with progression of the cell cycle, whereas the permeability decreases from early G1 to an apparent minimum in the S phase. These changes may be caused by cell cycle-dependent changes in the number of channels.
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Affiliation(s)
- A Takahashi
- Department of Physiology, School of Medicine, University of Tokushima, Japan
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32
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Fedorov YV, Yegorov YE, Zelenin AV. The short-term increase in extracellular potassium concentration causes DNA replication onset in density-inhibited cells. Exp Cell Res 1992; 203:488-90. [PMID: 1459208 DOI: 10.1016/0014-4827(92)90025-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The high potassium concentration effect on the human diploid fibroblasts (HDF) and 3T3 cells was investigated. The incubation of confluent cultures of HDF or 3T3 Swiss cells in the medium with 50 mM K+ for 35 min induced, 12 h later, the onset of DNA replication in a significant proportion of culture cell population. The same treatment had no effect upon the sparce cell cultures. No stimulation of DNA replication was observed in the absence of serum in culture medium.
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Affiliation(s)
- Y V Fedorov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow
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33
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Vodovnik L, Miklavcic D, Sersa G. Modified cell proliferation due to electrical currents. Med Biol Eng Comput 1992; 30:CE21-8. [PMID: 1487931 DOI: 10.1007/bf02446174] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In view of the evidence that electrical currents may enhance healing of chronic wounds and retard tumour growth it is suggested that these currents normalise cell proliferation. Additional support to this contention is given by two reports: one on healing of pressure sores in man and one on tumour growth retardation in mice. The effect of an ionic environment on the cell cycle is analysed. Finally a hypothesis attempting to explain the normalising effect of electrical currents on cell proliferation is proposed. It is known that non-dividing cells, e.g. mature neurons, have high transmembrane potential (TMP) whereas fast-dividing cells, e.g. cancerous cells, have low TMP. When a cell is exposed to an electrical field, one side of the cell becomes hyperpolarised while the opposite side is depolarised. Assuming a nonlinear relationship between TMP and the transmembrane ionic currents, it can be shown that in non-dividing cells their high TMP is lowered; whereas in cells with a high division rate, their low TMP is raised due to cell exposure to the external electrical field. These alterations in transmembrane potential could contribute to the normalisation of abnormal cell proliferation.
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Affiliation(s)
- L Vodovnik
- Faculty of Electrical & Computer Engineering, University of Ljubljana, Slovenia
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34
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Mikkelsen RB, Asher CR. Effects of hyperthermia on the membrane potential and Na+ transport of V79 fibroblasts. J Cell Physiol 1990; 144:216-21. [PMID: 2380252 DOI: 10.1002/jcp.1041440206] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effects of hyperthermia (41-43 degrees C) on the membrane potential (calculated from the transmembrane distribution of [3H]tetraphenylphosphonium) and Na+ transport of Chinese hamster V79 fibroblasts were studied. At 41 degrees C, hyperthermia induced a membrane hyperpolarization of log phase cells (5 to 26 mV) that was reversible upon returning to 37 degrees C. The hyperpolarization was inhibited 50% by 1 mM ouabain or 0.25 mM amiloride, an inhibitor of Na+:H+ exchange. Shifting temperature to 41 degrees C increased ouabain-sensitive Rb+ uptake indicating activation of the electrogenic Na+ pump. At 43 degrees C for 60 min, the membrane potential of log phase cells depolarized (20-35 mV). Parallel studies demonstrated enhanced Na+ uptake at 41 degrees C only in the presence of ouabain. At 43 degrees C, Na+ uptake was increased relative to controls with or without ouabain present. At both 41 and 43 degrees C, 0.25 mM amiloride inhibited heat-stimulated Na+ uptake. Na+ efflux was enhanced at 41 degrees C in a process inhibited by ouabain. Thus, one consequence of heat treatment at 41 degrees C is activation of Na+:H+ exchange with the resultant increase in cytosolic [Na+] activating the electrogenic Na+ pump. At temperatures greater than or equal to 43 degrees C, the Na+ pump is inhibited.
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Affiliation(s)
- R B Mikkelsen
- Department of Radiation Oncology, New England Medical Center, Boston, Massachusetts 02111
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35
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Glaser R. The influence of membrane electric field on cellular functions. SPRINGER SERIES IN BIOPHYSICS 1990. [DOI: 10.1007/978-3-642-74471-6_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Davies RJ, Mier L, Pempinello C, Asbun H, Funkhouser W. The electrical and sodium transport characteristics of sutured premalignant mouse colon. J Surg Res 1989; 47:149-54. [PMID: 2755118 DOI: 10.1016/0022-4804(89)90080-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Depolarization of the plasma membrane and increased sodium influx have both been suggested as mitogenic signals. Following bowel resection the intestinal suture line has been reported a fertile site for tumor recurrence. Whether alterations in cell surface signaling occur at suture lines has not been previously examined the electrical changes of sodium transport occurring at a suture line in an animal model of large bowel cancer. Forty-eight female CF1 mice underwent colotomies with repair utilizing silk or chromic sutures. Twenty-four mice underwent sham operations to serve as controls. The mice were injected subcutaneously with the carcinogen DMH (1,2-dimethylhydrazine) 20 mg/kg or an identical volume of 0.9% saline for 6 weeks and were sacrificed 1 week after the last injection. The sites of the sutured colotomies or a piece of distal colon from the sham-operated mice were mounted in a modified Ussing chamber and the electrical properties and unidirectional sodium fluxes were measured. The potential difference (pd) across the distal colon was not significantly different in any suture group compared to that in sham-operated controls when treated with saline (pd sham, -2.3 +/- 0.2 mV (mean +/- SEM); silk, -1.7 +/- 0.3 mV, chromic, -1.9 +/- 0.3 mV, P greater than 0.05, unpaired Student t test). The potential difference was significantly lowered in both suture groups compared to sham operated animals after treatment with DMH (pd sham, -2.6 +/- 0.3 mV; silk, -1.5 +/- 0.2 mV, P less than 0.05; chromic, -1.6 +/- 0.4 mV, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R J Davies
- Department of Surgery, VA Medical Center, San Diego, CA
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Abstract
Carcinogenic stimuli appear to act on target cells (and their daughters) by one or more of three mechanisms. The first is by oxidation of membrane component molecules on the extracellular surfaces of their plasma membranes. The second is by chronic and continuous impingement of electrons on the extracellular surfaces of their plasma membranes and the third is by relocation of predominantly basic molecules to the cytoplasmic surfaces of their plasma membranes. This latter effect in turn causes electrostatic attraction of image charged acidic molecules to the extracellular surfaces to balance the transmembrane charge of the target cells. Each of the above mechanisms results in a condition of increased electronegativity of the extracellular surfaces of plasma membranes of the target cells and their daughters. A theory of transformation is advanced based on the above related modes of action and it is used to explain some previously unexplainable properties of tumors.
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Affiliation(s)
- J A Beech
- University of Miami, Department of Epidemiology and Public Health, FL 33177-1411
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Arcangeli A, Ricupero L, Olivotto M. Commitment to differentiation of murine erythroleukemia cells involves a modulated plasma membrane depolarization through Ca2+-activated K+ channels. J Cell Physiol 1987; 132:387-400. [PMID: 2443510 DOI: 10.1002/jcp.1041320302] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The role of the plasma membrane potential (delta psi p) in the commitment to differentiation of murine erythroleukemia (MEL) cells has been studied by analyzing the ionic basis and the time course of this potential in the absence or the presence of different types of inducers. delta psi p was determined by measuring the distribution of tetraphenylphosphonium (TPP+) across the plasma membrane and displayed a 22-hour depolarization phase (from -28 to +5 mV) triggered by factors contained in foetal calf serum (FCS) and followed by a nearly symmetrical repolarization phase. After measuring the electrochemical equilibrium potential of Na+, K+, and Cl-, the relative contribution of these ions to delta psi p was evaluated by means of ion substitution experiments and by the addition of ion flux inhibitors (tetrodotoxin [TTX], 4-acetoamide-4'-isothiocyanostilbene-2,2'-disulfonate [SITS]) and ionophores (Valinomycin, A23187). The Na+ contribution to delta psi p appeared negligible, the potential being essentially generated by K+ and Cl- fluxes. When evaluated by a new mathematical approach, the effects of Valinomycin and A23187 at different times of incubation provided evidence that both the depolarization and the repolarization phase were due to variations of the K+ permeability across the plasma membrane (PK) mediated by Ca2+-activated K+ channels. All the inducers tested (dimethylsulfoxide [DMSO], hexamethylen-bis-acetamide [HMBA], diazepam), although they did not modify the ionic basis of delta psi p, strongly attenuated the depolarization rate of this potential. This attenuation was not brought about when the inducers were added to noninducible MEL cell clonal sublines. Cell commitment occurred only during the depolarization phase and increased proportionally to the attenuation of this phase up to a threshold beyond which the further increase of the attenuation was associated with the inhibition of commitment. The major role of the inducers apparently consisted of the stabilization of the Ca2+-activated K+ channels, suggesting that a properly modulated delta psi p depolarization through these channels is primarily involved in the signal generation for MEL cell commitment to differentiation.
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Affiliation(s)
- A Arcangeli
- Institute of General Pathology, Medical Faculty of the University of Florence, Italy
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Nagy I, Tóth L, Szállási Z, Lampé I. Energy-dispersive, bulk specimen X-ray microanalytical measurement of the intracellular Na+/K+ ratio in human laryngeal tumors. J Cancer Res Clin Oncol 1987; 113:197-202. [PMID: 3558455 DOI: 10.1007/bf00391444] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Energy-dispersive X-ray microanalysis was performed on human biopsy materials taken during laryngoscopic intervention in 18 cases. The removed tissue pieces were divided into two parts. One of them was used for pathohistological studies, the other was processed for X-ray microanalysis by the freeze-fracture freeze-drying method. Of the cases investigated 4 proved to be of benign character, whereas the rest contained carcinoma planocellulare keratoides or non-keratoides. Bulk specimen energy-dispersive X-ray microanalysis of 135 cells from the benign tissue samples revealed an average Na+/K+ molar ratio of 0.13 +/- 0.01 (SEM) in the intracellular space, with a regular Gaussian distribution. In the cases of carcinomas 641 cells were measured, the average of the same ratio was 0.67 +/- 0.03 (SEM) due mostly to an increase in the Na+ content. The distribution of data was apparently not normal in the cancerous samples. These observations and some theoretical considerations support the notion that the intracellular Na+/K+ ratio correlates with the proliferative capacity of tissues. The relevance of some recent biochemical results is also discussed in this respect.
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Koike T, Takashima A. Cell cycle-dependent modulation of biosynthesis and stimulus-evoked release of catecholamines in PC12 pheochromocytoma cells. J Neurochem 1986; 46:1493-500. [PMID: 2870133 DOI: 10.1111/j.1471-4159.1986.tb01767.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Catecholamine biosynthesis and its stimulus-evoked release in PC12 pheochromocytoma cells were studied as a function of cell cycle by means of HPLC with electrochemical detection. We found that 3,4-dihydroxyphenylethylamine (dopamine) levels in PC12 cells remained constant throughout the period of cell cycle. In contrast, the noradrenaline content was dependent on the cell cycle: it increased during the S + G2 phase followed by a decrease in the M phase. These results were confirmed further by measuring the activities catalyzing the catecholamine biosynthesis. Thus, activities of tyrosine 3-monooxygenase and 3,4-dihydroxyphenylalanine decarboxylase were independent of the cell cycle, whereas both soluble and membrane-bound dopamine beta-monooxygenase activities were modulated during the cell cycle. On the other hand, release of the catecholamines stimulated with 50 mM KCl increased in the G1 phase, reached a maximum in the late G1, and then gradually decreased in later periods. We also found that carbamylcholine-induced release of the catecholamines occurred maximally in the early S + G2 phase followed by a decrease during the M phase. Cell cycle dependence of the catecholamine release was in good agreement with that of 45Ca2+ uptake. Thus, this study provides evidence that the catecholamine biosynthesis and its release in PC12 cells are modulated during the period of cell cycle.
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41
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Factors influencing the accumulation of tetraphenylphosphonium cation in HeLa cells. Mol Cell Biol 1984. [PMID: 6700585 DOI: 10.1128/mcb.4.1.199] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Exposure of HeLa cells to tetraphenylphosphonium cation (TPP+) results in a rapid accumulation intracellularly, and a steady-state level is reached within 10 min. Accumulation of [3H]TPP+ in HeLa cells is reduced under the following conditions: (i) after preincubation of cells in buffered saline or in medium containing two- to fourfold higher concentrations of amino acids, (ii) exposure to the alkylating agent L-1-tosylamido-2-phenyl-ethylchloromethyl ketone, (iii) ouabain-mediated inhibition of the Na+, K+ ATPase, and (iv) high external K+ concentrations. In contrast, addition of serum increases the uptake of TPP+. In synchronized cells, intracellular levels of TPP+ differ at various stages of cell cycle and are lowest in mitosis.
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42
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Hiller R, Schaefer A, Zibirre R, Kaback HR, Koch G. Factors influencing the accumulation of tetraphenylphosphonium cation in HeLa cells. Mol Cell Biol 1984; 4:199-202. [PMID: 6700585 PMCID: PMC368676 DOI: 10.1128/mcb.4.1.199-202.1984] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Exposure of HeLa cells to tetraphenylphosphonium cation (TPP+) results in a rapid accumulation intracellularly, and a steady-state level is reached within 10 min. Accumulation of [3H]TPP+ in HeLa cells is reduced under the following conditions: (i) after preincubation of cells in buffered saline or in medium containing two- to fourfold higher concentrations of amino acids, (ii) exposure to the alkylating agent L-1-tosylamido-2-phenyl-ethylchloromethyl ketone, (iii) ouabain-mediated inhibition of the Na+, K+ ATPase, and (iv) high external K+ concentrations. In contrast, addition of serum increases the uptake of TPP+. In synchronized cells, intracellular levels of TPP+ differ at various stages of cell cycle and are lowest in mitosis.
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43
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Felber SM, Brand MD. Early plasma-membrane-potential changes during stimulation of lymphocytes by concanavalin A. Biochem J 1983; 210:885-91. [PMID: 6409082 PMCID: PMC1154303 DOI: 10.1042/bj2100885] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
1. We have monitored the plasma-membrane potential of lymphocytes by measuring the accumulation of the lipophilic cation methyltriphenylphosphonium (TPMP+) in the presence of the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP). 2. The mitogen concanavalin A causes a decrease in TPMP+ accumulation by pig lymphocytes corresponding to a 3 mV depolarization with 2 1/2 min. Concanavalin A does not alter 86Rb+ uptake in the first 30 min. 3. In contrast concanavalin A increased TPMP+ accumulation and the rate of Rb+ uptake in mouse thymocytes. This is consistent with a previous proposal that the mitogen induces a hyperpolarization of mouse thymocytes as a result of stimulation of a Ca2+-dependent K+ channel. 4. Studies with the calcium ionophore A23187 and quinine (an inhibitor of the Ca2+-dependent K+ channel) suggest that the channel is partially closed in mouse resting thymocytes but is almost fully active in pig resting cells. Thus concanavalin A hyperpolarizes mouse thymocytes by activating the Ca2+-dependent K+ channel but cannot do so in pig lymphocytes because the channel is already maximally activated. 5. The 3mV depolarization of pig cells cannot be explained by a decrease in electrogenic K+ permeability.
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44
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Deutsch C, Slater L, Goldstein P. Volume regulation of human peripheral blood lymphocytes and stimulated proliferation of volume-adapted cells. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 721:262-7. [PMID: 6293587 DOI: 10.1016/0167-4889(82)90078-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Human peripheral blood lymphocytes exposed to hypotonic media (Ca/Mg-free, room temp.) first swell and then shrink. This shrinking response is characterized by a simple exponential with a half-time of 1.44 +/- 0.60 min (n = 11) and its extent but not the half-time for a given hypotonicity is influenced by [K+]0. Using K-selective electrodes, we observe a change in [K+]0 when cells are diluted into hypotonic media. A half-time of 1.55 +/- 0.06 min (n = 4) was obtained. A similar half-time was obtained by assay of total cell K using atomic absorption spectroscopy. At all osmolarities [K+]i was decreased from control values and was constant as [K+]0 was increased. Short-term incubation with ouabain (10(-4) M) had no effect. Decreasing osmolarities progressively inhibited phytohemagglutinin-stimulated DNA synthesis, yet cell number and viability remained unaltered. Our evidence indicates that the volume response is mediated by a change in the passive permeability of the plasma membrane to K and/or to the accompanying anions, and that the consequently volume-adapted cells are growth-inhibited.
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45
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Abstract
The transmembrane electrical potential has been measured across human peripheral blood lymphocytes under culture conditions using equilibrium distributions of the lipophilic cation 3H-tetraphenylphosphonium (TPP). The TPP equilibrates to a steady-state level that gives calculated voltages of -80 mV for unstimulated lymphocytes. This value of the potential is constant during the first few hours of succinyl concanavalin A stimulation. When the transmembrane electrical potential is lowered by isotonic replacement of Na with K, this neither by itself stimulates proliferation nor does it inhibit mitogen-stimulated proliferation. Lymphocytes with similar membrane potentials, such as those incubated in normal-Na MEM and low-Na-mannitol MEM, exhibit drastically different proliferative responses to mitogen stimulation (Deutsch et al., 1981). These results show that isotonic replacement of K for Na prevents low Na inhibition of DNA synthesis and that at least during the first 2.5 hours of lymphocyte activation transmembrane electrical potential per se does not play a significant role in the activation process.
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46
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Baxter MA, Chahwala SB, Hickman JA, Spurgin GE. The effects of nitrogen mustard (HN2) on activities of the plasma membrane of PC6A mouse plasmacytoma cells. Biochem Pharmacol 1982; 31:1773-8. [PMID: 6213233 DOI: 10.1016/0006-2952(82)90683-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Nitrogen mustard, HN2 (10(-5) M), inhibited the transport of the potassium congener 86rubidium into PC6A mouse plasmacytoma cells by 45% after a 4 hr incubation at 37 degree in vitro. HN2 (10(-3) M) had a rapid effect on the profile of 86rubidium transport into PC6A cells when added simultaneously with the 86rubidium whereas a monofunctional analogue of HN2((2-chloroethyl)dimethylamine) had no effect at 10(-3) M. The transport of the amino acid analogues alpha-aminoisobutyric acid and cycloleucine into PC6A cells was inhibited by 19% and 5% respectively after a 4 hr incubation with 10(-5) M HN2. The results suggest that the activity of plasma membrane Na+K+-ATPase may be affected by HN2. This enzyme may play a pivotal role in controlling cell growth and division. Crude cell membrane preparations from PC6A cells had variable Na+K+-ATPase activity which was possibly due to contamination with mitochondrial Mg2+-ATPase. Incubation of a crude cell membrane preparation in the presence of 40 nM dicyclohexylcarbodiimide gave constant Na+K+-ATPase activity which was inhibited by 44% on incubation with HN2 (10(-3) M) for 0.5 hr. The monofunctional analogue of HN2 inhibited this preparation by only 7% under the same conditions. It is suggested that inhibition of Na+K+-ATPase by HN2 may be an important facet of its cytotoxic activity.
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47
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de Laat SW, van der Saag PT. The plasma membrane as a regulatory site in growth and differentiation of neuroblastoma cells. INTERNATIONAL REVIEW OF CYTOLOGY 1982; 74:1-54. [PMID: 6288609 DOI: 10.1016/s0074-7696(08)61168-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Nagy IZ, Lustyik G, Nagy VZ, Zarándi B, Bertoni-Freddari C. Intracellular Na+:K+ ratios in human cancer cells as revealed by energy dispersive x-ray microanalysis. J Biophys Biochem Cytol 1981; 90:769-77. [PMID: 7287822 PMCID: PMC2111914 DOI: 10.1083/jcb.90.3.769] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Intranuclear sodium, potassium, and chloride contents were measured by energy-dispersive x-ray microanalysis in freeze-fractured, freeze-dried, bulk-tumor samples taken from 10 patients suffering from invasive urogenital cancers. Human biopsies were carried out during the first diagnostic interventions before any cytostatic treatment had been applied. Pathohistological diagnosis established the malignancy in each case. The cancers were classified in three types: keratinizing, transitional cell, and hypernephroid carcinoma. More than 250 cell nuclei were measured from each type of cancer. The results were compared with those obtained in intact human urothelium taken from patients having no malignant processes. Proximal and distal tubular epithelial cell nuclei representing the origin of human hypernephroid cancer were also measured in rat kidney because corresponding healthy human material cannot be obtained. The analyses revealed, in all three types of cancer cells, that the average intranuclear sodium content increased more than three-fold, the potassium content decreased 32, 16, and 13%, respectively; meanwhile the chloride content increased, but to a lesser extent than did the sodium. The intranuclear Na+:K+ ratios were more than five-fold higher in the cancer cells on the average, and their distribution histograms were much broader than in the normal human urothelium and in the tubular cell nuclei of the rat kidney. The results obtained fit well with the theory of Cone, C. D., Jr. 1971. J. Theor. Biol. 30: 151-181 according to which the sustained depolarization of the cell membrane may be of mitogenic effect.
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Boonstra J, Mummery CL, Tertoolen LG, Van der Saag PT, De Laat SW. Characterization of 42K+ and 86Rb+ transport and electrical membrane properties in exponentially growing neuroblastoma cells. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 643:89-100. [PMID: 7236694 DOI: 10.1016/0005-2736(81)90221-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
For measuring K+ efflux from exponentially growing neuroblastoma cells (clone Neuro-2A), two methods were used, a sampling method and a washing method. Both methods indicated that K+ efflux kinetics were as from a two-compartment system, but the two compartments could only be resolved completely using the washing method. A fast compartment, containing 143 +/- 16 nmol K+/10(6) cells, was found to be associated to the cell surface, and a slow compartment, containing 151 +/- 7 nmol K+/10(6) cells, was found to represent the intracellular K+. The rate constant of the slow compartment was 0.0164 +/-0.0005 min-1, and the K+ efflux rate was 2.46 +/- 0.14 nmol K+/10(6) cells per min. Using the appropriate conditions to measure K+ influx, the kinetics of influx were equal to the kinetics of efflux, indicating steady-state conditions. In addition a comparison was made between 42K+ and 86Rb+ as radioactive tracers for K+ flux. It was found that 86Rb+ was specifically bound on both the inside and the outside of the cells, and for this reason was not a suitable tracer for studying K+ flux kinetics in neuro-2A cells. A membrane potential of -42.9 +/- 1.3 mV and intracellular K+ activity of 108.1 +/- 3.0 mM were measured using conventional and ion-selective microelectrodes. A correlation was made between the K+ flux and electrophysiological data, using the equations of electrodiffusion theory. Thus, the permeabilities of K+ and Na+ were calculated as (3.9 +/- 0.4) . 10(-8) cm/s and (0.6 and 0.1) . 10(-8) cm/s respectively, together with K+ conductance of (2.8 +/- 0.3) . 10(-6) omega-1/cm2.
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50
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Mummery CL, Boonstra J, Van Der Saag PT, de Laat SW. Modulation of functional and optimal (Na+-K+)ATPase activity during the cell cycle of neuroblastoma cells. J Cell Physiol 1981; 107:1-9. [PMID: 6260824 DOI: 10.1002/jcp.1041070102] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Functional and optimal activities of the (Na+-K+)ATPase, as determined by ouabain-sensitive K+ influx in intact cells and ATP hydrolysis in cell homogenates respectively, have been measured during the cell cycle of neuroblastoma (clone Neuro-2A) cells. The cells were synchronized by selective detachment of mitotic cells. The ouabain-sensitive K+ influx decreased more than fourfold from 1.62 +/- 0.11 nmoles/min/10(6) cells to 0.36 +/- 0.25 nmoles/min/10(6) cells on passing from mitosis to early G1 phase. On entry into S phase a transient sixfold increase to 2.07 +/- 0.30 nmoles/min/10(6) cells was observed, followed by a rapid decline, after which the active K+ influx rose again steadily from 1.03 +/- 0.25 nmoles/min/10(6) cells in early S phase to 2.10 +/- 0.92 nmoles/min/10(6) cells just prior to the next mitosis. The ouabain-insensitive component rose linearly through the cycle in the same manner as the protein content/cell. Combining total K+ influx values with efflux data obtained previously showed that net loss of K+ occurred with transition from mitosis to G1 phase while net accumulation occurred with entry into S. Throughout mid-S phase net K+ flux was virtually zero, but a large net influx occurred again just before the next mitosis. The (Na+-K+)ATPase activity measured in cell homogenates decreased rapidly from mitosis to G1 phase and increased steadily throughout S phase, but the transient activation on entry into S phase was not observed. Complete inhibition of the (Na+-K+)ATPase mediated K+ influx by ouabain (5 mM) prevents the cells from entering S phase, while partial inhibition by lower concentrations of ouabain (0.2 and 0.5 mM; km = 0.17 mM) causes partial blockage in G1 and, to a lesser extent, a reduced rate of progression through the rest of the cell cycle. We conclude that the transient increase in (Na+-K+)ATPase mediated K+ influx at the G1/S transition is a prerequisite for entry into S phase, while maintenance of adequate levels of K+ influx is necessary for normal rate of progression through the rest of the cell cycle.
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