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Kostritskaia Y, Klüssendorf M, Pan YE, Hassani Nia F, Kostova S, Stauber T. Physiological Functions of the Volume-Regulated Anion Channel VRAC/LRRC8 and the Proton-Activated Chloride Channel ASOR/TMEM206. Handb Exp Pharmacol 2024; 283:181-218. [PMID: 37468723 DOI: 10.1007/164_2023_673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
Volume-regulated anion channels (VRACs) and the acid-sensitive outwardly rectifying anion channel (ASOR) mediate flux of chloride and small organic anions. Although known for a long time, they were only recently identified at the molecular level. VRACs are heteromers consisting of LRRC8 proteins A to E. Combining the essential LRRC8A with different LRRC8 paralogues changes key properties of VRAC such as conductance or substrate selectivity, which is how VRACs are involved in multiple physiological functions including regulatory volume decrease, cell proliferation and migration, cell death, purinergic signalling, fat and glucose metabolism, insulin signalling, and spermiogenesis. VRACs are also involved in pathological conditions, such as the neurotoxic release of glutamate and aspartate. Certain VRACs are also permeable to larger, organic anions, including antibiotics and anti-cancer drugs, making them an interesting therapeutic target. ASOR, also named proton-activated chloride channel (PAC), is formed by TMEM206 homotrimers on the plasma membrane and on endosomal compartments where it mediates chloride flux in response to extracytosolic acidification and plays a role in the shrinking and maturation of macropinosomes. ASOR has been shown to underlie neuronal swelling which causes cell death after stroke as well as promoting the metastasis of certain cancers, making them intriguing therapeutic targets as well.
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Affiliation(s)
- Yulia Kostritskaia
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Malte Klüssendorf
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Yingzhou Edward Pan
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Fatemeh Hassani Nia
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Simona Kostova
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Tobias Stauber
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany.
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2
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Kulkarni S, Li Q, Singhi AD, Liu S, Monga SP, Feranchak AP. TMEM16A partners with mTOR to influence pathways of cell survival, proliferation, and migration in cholangiocarcinoma. Am J Physiol Gastrointest Liver Physiol 2023; 325:G122-G134. [PMID: 37219012 PMCID: PMC10390053 DOI: 10.1152/ajpgi.00270.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 05/04/2023] [Accepted: 05/17/2023] [Indexed: 05/24/2023]
Abstract
Expression of transmembrane protein 16 A (TMEM16A), a calcium activated chloride channel, is elevated in some human cancers and impacts tumor cell proliferation, metastasis, and patient outcome. Evidence presented here uncovers a molecular synergy between TMEM16A and mechanistic/mammalian target of rapamycin (mTOR), a serine-threonine kinase that is known to promote cell survival and proliferation in cholangiocarcinoma (CCA), a lethal cancer of the secretory cells of bile ducts. Analysis of gene and protein expression in human CCA tissue and CCA cell line detected elevated TMEM16A expression and Cl- channel activity. The Cl- channel activity of TMEM16A impacted the actin cytoskeleton and the ability of cells to survive, proliferate, and migrate as revealed by pharmacological inhibition studies. The basal activity of mTOR, too, was elevated in the CCA cell line compared with the normal cholangiocytes. Molecular inhibition studies provided further evidence that TMEM16A and mTOR were each able to influence the regulation of the other's activity or expression respectively. Consistent with this reciprocal regulation, combined TMEM16A and mTOR inhibition produced a greater loss of CCA cell survival and migration than their individual inhibition alone. Together these data reveal that the aberrant TMEM16A expression and cooperation with mTOR contribute to a certain advantage in CCA.NEW & NOTEWORTHY This study points to the dysregulation of transmembrane protein 16 A (TMEM16A) expression and activity in cholangiocarcinoma (CCA), the inhibition of which has functional consequences. Dysregulated TMEM16A exerts an influence on the regulation of mechanistic/mammalian target of rapamycin (mTOR) activity. Moreover, the reciprocal regulation of TMEM16A by mTOR demonstrates a novel connection between these two protein families. These findings support a model in which TMEM16A intersects the mTOR pathway to regulate cell cytoskeleton, survival, proliferation, and migration in CCA.
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Affiliation(s)
- Sucheta Kulkarni
- Division of Gastroenterology, Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Qin Li
- Division of Gastroenterology, Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Aatur D Singhi
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Silvia Liu
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Satdarshan P Monga
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Andrew P Feranchak
- Division of Gastroenterology, Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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3
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Giordano ME, Udayan G, Guascito MR, De Bartolomeo AR, Carlino A, Conte M, Contini D, Lionetto MG. Apoptotic volume decrease (AVD) in A 549 cells exposed to water-soluble fraction of particulate matter (PM 10). Front Physiol 2023; 14:1218687. [PMID: 37492639 PMCID: PMC10364053 DOI: 10.3389/fphys.2023.1218687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 06/21/2023] [Indexed: 07/27/2023] Open
Abstract
Exposure to atmospheric particulate matter (PM) is recognized as a human health risk factor of great concern. The present work aimed to study the cellular mechanisms underlying cytotoxic effects of airborne particulate matter <10 µm in size (PM10), sampled in an urban background site from January to May 2020, on A549 cells. In particular, the study addressed if PM10 exposure can be a main factor in the induction of the Apoptotic Volume Decrease (AVD), which is one of the first events of apoptosis, and if the generation of intracellular oxidative stress can be involved in the PM10 induction of apoptosis in A549 cells. The cytotoxicity of PM10 samples was measured by MTT test on cells exposed for 24 h to the PM10 aqueous extracts, cell volume changes were monitored by morphometric analysis of the cells, apoptosis appearance was detected by annexin V and the induction of intracellular oxidative stress was evaluated by the ROS sensitive CM-H2DCFDA fluorescent probe. The results showed cytotoxic effects ascribable to apoptotic death in A549 cells exposed for 24 h to aqueous extracts of airborne winter PM10 samples characterized by high PM10 value and organic carbon content. The detected reduced cell viability in winter samples ranged from 55% to 100%. Normotonic cell volume reduction (ranging from about 60% to 30% cell volume decrease) after PM10 exposure was already detectable after the first 30 min clearly indicating the ability of PM10, mainly arising from biomass burning, to induce Apoptotic Volume Decrease (AVD) in A549 cells. AVD was prevented by the pre-treatment with 0.5 mM SITS indicating the activation of Cl- efflux presumably through the activation of VRAC channels. The exposure of A549 cells to PM10 aqueous extracts was able to induce intracellular oxidative stress detected by using the ROS-sensitive probe CM-H2DCFDA. The PM10-induced oxidative stress was statistically significantly correlated with cell viability inhibition and with apoptotic cell shrinkage. It was already evident after 15 min exposure representing one of the first cellular effects caused by PM exposure. This result suggests the role of oxidative stress in the PM10 induction of AVD as one of the first steps in cytotoxicity.
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Affiliation(s)
- M E Giordano
- Department Biological and Environmental Sciences and Technologies (DiSTeBA), Salento University, Lecce, Italy
| | - G Udayan
- Department Biological and Environmental Sciences and Technologies (DiSTeBA), Salento University, Lecce, Italy
| | - M R Guascito
- Department Biological and Environmental Sciences and Technologies (DiSTeBA), Salento University, Lecce, Italy
| | - A R De Bartolomeo
- Department Biological and Environmental Sciences and Technologies (DiSTeBA), Salento University, Lecce, Italy
| | - A Carlino
- Department Biological and Environmental Sciences and Technologies (DiSTeBA), Salento University, Lecce, Italy
| | - M Conte
- Institute of Atmospheric Sciences and Climate, ISAC-CNR, Rome, Italy
| | - D Contini
- Institute of Atmospheric Sciences and Climate, ISAC-CNR, Lecce, Italy
| | - M G Lionetto
- Department Biological and Environmental Sciences and Technologies (DiSTeBA), Salento University, Lecce, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
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Huisman C, Norgard MA, Levasseur PR, Krasnow SM, van der Wijst MGP, Olson B, Marks DL. Critical changes in hypothalamic gene networks in response to pancreatic cancer as found by single-cell RNA sequencing. Mol Metab 2022; 58:101441. [PMID: 35031523 PMCID: PMC8851272 DOI: 10.1016/j.molmet.2022.101441] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/06/2022] [Accepted: 01/08/2022] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE Cancer cachexia is a devastating chronic condition characterized by involuntary weight loss, muscle wasting, abnormal fat metabolism, anorexia, and fatigue. However, the molecular mechanisms underlying this syndrome remain poorly understood. In particular, the hypothalamus may play a central role in cachexia, given that it has direct access to peripheral signals because of its anatomical location and attenuated blood-brain barrier. Furthermore, this region has a critical role in regulating appetite and metabolism. METHODS To provide a detailed analysis of the hypothalamic response to cachexia, we performed single-cell RNA-seq combined with RNA-seq of the medial basal hypothalamus (MBH) in a mouse model for pancreatic cancer. RESULTS We found many cell type-specific changes, such as inflamed endothelial cells, stressed oligodendrocyes and both inflammatory and moderating microglia. Lcn2, a newly discovered hunger suppressing hormone, was the highest induced gene. Interestingly, cerebral treatment with LCN2 not only induced many of the observed molecular changes in cachexia but also affected gene expression in food-intake decreasing POMC neurons. In addition, we found that many of the cachexia-induced molecular changes found in the hypothalamus mimic those at the primary tumor site. CONCLUSION Our data reveal that multiple cell types in the MBH are affected by tumor-derived factors or host factors that are induced by tumor growth, leading to a marked change in the microenvironment of neurons critical for behavioral, metabolic, and neuroendocrine outputs dysregulated during cachexia. The mechanistic insights provided in this study explain many of the clinical features of cachexia and will be useful for future therapeutic development.
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Affiliation(s)
- Christian Huisman
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States; Knight Cancer Institute, Oregon Health & Science University, Portland, United States.
| | - Mason A Norgard
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States
| | - Peter R Levasseur
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States
| | - Stephanie M Krasnow
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States
| | - Monique G P van der Wijst
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Brennan Olson
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States; Medical Scientist Training Program, Oregon Health & Science University, Portland, United States
| | - Daniel L Marks
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States; Knight Cancer Institute, Oregon Health & Science University, Portland, United States; Brenden-Colson Center for Pancreatic Care, Oregon Health & Science University, Portland, United States.
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5
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Kittl M, Winklmayr M, Preishuber-Pflügl J, Strobl V, Gaisberger M, Ritter M, Jakab M. Low pH Attenuates Apoptosis by Suppressing the Volume-Sensitive Outwardly Rectifying (VSOR) Chloride Current in Chondrocytes. Front Cell Dev Biol 2022; 9:804105. [PMID: 35186954 PMCID: PMC8847443 DOI: 10.3389/fcell.2021.804105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/31/2021] [Indexed: 11/25/2022] Open
Abstract
In a variety of physiological and pathophysiological conditions, cells are exposed to acidic environments. Severe synovial fluid acidification also occurs in a progressive state of osteoarthritis (OA) affecting articular chondrocytes. In prior studies extracellular acidification has been shown to protect cells from apoptosis but the underlying mechanisms remain elusive. In the present study, we demonstrate that the inhibition of Cl− currents plays a significant role in the antiapoptotic effect of acidification in human articular chondrocytes. Drug-induced apoptosis was analyzed after exposure to staurosporine by caspase 3/7 activity and by annexin-V/7-actinomycin D (7-AAD) staining, followed by flow cytometry. Cell viability was assessed by resazurin, CellTiter-Glo and CellTiter-Fluor assays. Cl− currents and the mean cell volume were determined using the whole cell patch clamp technique and the Coulter method, respectively. The results reveal that in C28/I2 cells extracellular acidification decreases caspase 3/7 activity, enhances cell viability following staurosporine treatment and gradually deactivates the volume-sensitive outwardly rectifying (VSOR) Cl− current. Furthermore, the regulatory volume decrease (RVD) as well as the apoptotic volume decrease (ADV), which represents an early event during apoptosis, were absent under acidic conditions after hypotonicity-induced cell swelling and staurosporine-induced apoptosis, respectively. Like acidosis, the VSOR Cl− current inhibitor DIDS rescued chondrocytes from apoptotic cell death and suppressed AVD after induction of apoptosis with staurosporine. Similar to acidosis and DIDS, the VSOR channel blockers NPPB, niflumic acid (NFA) and DCPIB attenuated the staurosporine-induced AVD. NPPB and NFA also suppressed staurosporine-induced caspase 3/7 activation, while DCPIB and Tamoxifen showed cytotoxic effects per se. From these data, we conclude that the deactivation of VSOR Cl− currents impairs cell volume regulation under acidic conditions, which is likely to play an important role in the survivability of human articular chondrocytes.
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Affiliation(s)
- Michael Kittl
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis and Rehabilitation, Salzburg, Austria
- *Correspondence: Michael Kittl,
| | - Martina Winklmayr
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis and Rehabilitation, Salzburg, Austria
| | - Julia Preishuber-Pflügl
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Gastein Research Institute, Paracelsus Medical University, Salzburg, Austria
| | - Victoria Strobl
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Gastein Research Institute, Paracelsus Medical University, Salzburg, Austria
| | - Martin Gaisberger
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis and Rehabilitation, Salzburg, Austria
- Gastein Research Institute, Paracelsus Medical University, Salzburg, Austria
| | - Markus Ritter
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis and Rehabilitation, Salzburg, Austria
- Gastein Research Institute, Paracelsus Medical University, Salzburg, Austria
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology, Pathophysiology and Biophysics—Nuremberg, Paracelsus Medical University, Nuremberg, Germany
| | - Martin Jakab
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis and Rehabilitation, Salzburg, Austria
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Kolobkova Y, Pervaiz S, Stauber T. The expanding toolbox to study the LRRC8-formed volume-regulated anion channel VRAC. CURRENT TOPICS IN MEMBRANES 2021; 88:119-163. [PMID: 34862024 DOI: 10.1016/bs.ctm.2021.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The volume-regulated anion channel (VRAC) is activated upon cell swelling and facilitates the passive movement of anions across the plasma membrane in cells. VRAC function underlies many critical homeostatic processes in vertebrate cells. Among them are the regulation of cell volume and membrane potential, glutamate release and apoptosis. VRAC is also permeable for organic osmolytes and metabolites including some anti-cancer drugs and antibiotics. Therefore, a fundamental understanding of VRAC's structure-function relationships, its physiological roles, its utility for therapy of diseases, and the development of compounds modulating its activity are important research frontiers. Here, we describe approaches that have been applied to study VRAC since it was first described more than 30 years ago, providing an overview of the recent methodological progress. The diverse applications reflecting a compromise between the physiological situation, biochemical definition, and biophysical resolution range from the study of VRAC activity using a classic electrophysiology approach, to the measurement of osmolytes transport by various means and the investigation of its activation using a novel biophysical approach based on fluorescence resonance energy transfer.
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Affiliation(s)
- Yulia Kolobkova
- Department of Human Medicine and Institute for Molecular Medicine, MSH Medical School Hamburg, Germany
| | - Sumaira Pervaiz
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Germany
| | - Tobias Stauber
- Department of Human Medicine and Institute for Molecular Medicine, MSH Medical School Hamburg, Germany; Institute of Chemistry and Biochemistry, Freie Universität Berlin, Germany.
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Yurinskaya V, Aksenov N, Moshkov A, Goryachaya T, Shemery A, Vereninov A. Flow fluorometry quantification of anion channel VRAC subunit LRRC8A at the membrane of living U937 cells. Channels (Austin) 2021; 14:45-52. [PMID: 32075501 PMCID: PMC7039630 DOI: 10.1080/19336950.2020.1730535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Assessing the expression of channels on the cell membrane is a necessary step in studying the functioning of ion channels in living cells. We explore, first, if endogenous VRAC can be assayed using flow cytometry and a commercially available antibody against an extracellular loop of the LRRC8A, also known as SWELL1, subunit of the VRAC channel. The second goal is to determine if an increase in the number of VRAC channels at the cell membrane is responsible for an increase in chloride permeability of the membrane in two well-known cases: during staurosporine (STS)-induced apoptosis and after water balance disturbance caused by hypotonic medium. Human suspension lymphoid cells U937 were used as they are suitable for flow fluorometry and because we have recently studied their membrane chloride permeability during apoptosis. We found that surface expression of endogenous LRRC8A subunits can be quantified in living U937 cells using flow fluorometry with the Alomone Lab antibody. Further, we revealed that treatment of cells for 1 hour using STS or a hypotonic solution did not change the number of LRRC8A subunits to the extent that would correspond to changes in the membrane chloride permeability determined by ion content analysis. This indicates that prolonged increase in chloride permeability of the cell membrane during apoptotic cell shrinkage or cell volume regulation under hypotonicity in U937 cells occurs without altering cell surface expression of VRAC.
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Affiliation(s)
| | - Nikolay Aksenov
- Institute of Cytology, Russian Academy of Sciences, St-Petersburg, Russia
| | - Alexey Moshkov
- Institute of Cytology, Russian Academy of Sciences, St-Petersburg, Russia
| | - Tatyana Goryachaya
- Institute of Cytology, Russian Academy of Sciences, St-Petersburg, Russia
| | - Ashley Shemery
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Alexey Vereninov
- Institute of Cytology, Russian Academy of Sciences, St-Petersburg, Russia
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Lambert IH, Nielsen D, Stürup S. Impact of the histone deacetylase inhibitor trichostatin A on active uptake, volume-sensitive release of taurine, and cell fate in human ovarian cancer cells. Am J Physiol Cell Physiol 2020; 318:C581-C597. [PMID: 31913698 DOI: 10.1152/ajpcell.00460.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The histone deacetylase inhibitor trichostatin A (TSA) reduces cell viability in cisplatin-sensitive (A2780WT) and cisplatin-resistant (A2780RES) human ovarian cancer cells due to progression of apoptosis (increased caspase-9 activity), autophagy (increased LC3-II expression), and cell cycle arrest (increased p21 expression). The TSA-mediated effect on p21 and caspase-9 is mainly p53 independent. Cisplatin increases DNA-damage (histone H2AX phosphorylation) in A2780WT cells, whereas cisplatin, due to reduced uptake [inductively coupled-plasma-mass spectrometry (Pt) analysis], has no DNA-damaging effect in A2780RES cells. TSA has no effect on cisplatin accumulation or cisplatin-induced DNA-damage in A2780WT/A2780RES cells. Tracer technique indicates that TSA inhibits the volume-sensitive organic anion channel (VSOAC) in A2780WT/A2780RES cells and that the activity is restored by exogenous H2O2. As TSA reduces NOX4 mRNA accumulation and concomitantly increases catalase mRNA/protein accumulation, we suggest that TSA increases the antioxidative defense in A2780 cells. Inhibition of the kinase mTOR (rapamycin, palomid, siRNA), which is normally associated with cell growth, reduces VSOAC activity synergistically to TSA. However, as TSA increases mTOR activity (phosphorylation of 4EBP1, S6 kinase, S6, ULK1, SGK1), the effect of TSA on VSOAC activity does not reflect the shift in mTOR signaling. Upregulation of the protein expression and activity of the taurine transporter (TauT) is a phenotypic characteristic of A2780RES cells. However, TSA reduces TauT protein expression in A2780RES cells and activity to values seen in A2780WT cells. It is suggested that therapeutic benefits of TSA in A2780 do not imply facilitation of cisplatin uptake but more likely a synergistic activation of apoptosis/autophagy and reduced TauT activity.
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Affiliation(s)
- Ian Henry Lambert
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Dorthe Nielsen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Stefan Stürup
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark
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Lu P, Ding Q, Li X, Ji X, Li L, Fan Y, Xia Y, Tian D, Liu M. SWELL1 promotes cell growth and metastasis of hepatocellular carcinoma in vitro and in vivo. EBioMedicine 2019; 48:100-116. [PMID: 31597595 PMCID: PMC6838441 DOI: 10.1016/j.ebiom.2019.09.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 12/20/2022] Open
Abstract
Background SWELL1 was recently demonstrated to be an indispensable part of the volume-regulated anion channel (VRAC). VRAC is reported to participate in cell proliferation, survival, and migration. However, the correlation between SWELL1 and hepatocellular carcinoma (HCC) remains poorly-understood. In this study, we tried to explore the role of SWELL1 in HCC. Methods Immunohistochemistry and quantitative real-time-PCR (qRT-PCR) was used to measure SWELL1 expression in HCC samples obtained from patients with HCC. The effects of SWELL1 on HCC cell proliferation, apoptosis, and metastasis were analysed by corresponding cytological experiments including Cell Counting Kit-8 (CCK8), colony-forming, 5-ethynyl-2′-deoxyuridine (EdU), cell cycle analysis, TUNEL, Annexin V and PI staining, wound healing, transwell, and so on. BALB/c nude mice were used for the in vivo assays. qRT-PCR and western blotting was performed for molecular mechanisms. Findings SWELL1 was highly expressed in HCC tissues, and related to the poor prognosis. In vitro, the over-expression of SWELL1 significantly induced cell proliferation and migration, and inhibited apoptosis, whereas suppressing SWELL1 had the opposite effects. Moreover, knockdown of SWELL1 suppressed the growth and metastasis of HCC in vivo. Further experiments revealed that SWELL1 induced cell growth by activating the cyclinD1/CDK2 pathway via the connection with PKCa at the signalling level, and regulated cell migration through the JNK pathway in HCC. Interpretation SWELL1 acts as a promoter in the growth and metastasis of HCC cells and may be a potential intervention target for HCC. Fund This work is supported by the National Natural Science Foundation of China (No. 81572422, 81700515).
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Affiliation(s)
- Panpan Lu
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Qiang Ding
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Xin Li
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Xiaoyu Ji
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Lili Li
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Yuhui Fan
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China; Department of Gastroenterology, Internal Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Yujia Xia
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Dean Tian
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Mei Liu
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China.
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10
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Chen L, König B, Liu T, Pervaiz S, Razzaque YS, Stauber T. More than just a pressure relief valve: physiological roles of volume-regulated LRRC8 anion channels. Biol Chem 2019; 400:1481-1496. [DOI: 10.1515/hsz-2019-0189] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 04/27/2019] [Indexed: 12/29/2022]
Abstract
Abstract
The volume-regulated anion channel (VRAC) is a key player in the volume regulation of vertebrate cells. This ubiquitously expressed channel opens upon osmotic cell swelling and potentially other cues and releases chloride and organic osmolytes, which contributes to regulatory volume decrease (RVD). A plethora of studies have proposed a wide range of physiological roles for VRAC beyond volume regulation including cell proliferation, differentiation and migration, apoptosis, intercellular communication by direct release of signaling molecules and by supporting the exocytosis of insulin. VRAC was additionally implicated in pathological states such as cancer therapy resistance and excitotoxicity under ischemic conditions. Following extensive investigations, 5 years ago leucine-rich repeat-containing family 8 (LRRC8) heteromers containing LRRC8A were identified as the pore-forming components of VRAC. Since then, molecular biological approaches have allowed further insight into the biophysical properties and structure of VRAC. Heterologous expression, siRNA-mediated downregulation and genome editing in cells, as well as the use of animal models have enabled the assessment of the proposed physiological roles, together with the identification of new functions including spermatogenesis and the uptake of antibiotics and platinum-based cancer drugs. This review discusses the recent molecular biological insights into the physiology of VRAC in relation to its previously proposed roles.
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Affiliation(s)
- Lingye Chen
- Institut für Chemie und Biochemie , Freie Universität Berlin , Thielallee 63 , D-14195 Berlin , Germany
| | - Benjamin König
- Institut für Chemie und Biochemie , Freie Universität Berlin , Thielallee 63 , D-14195 Berlin , Germany
| | - Tianbao Liu
- Institut für Chemie und Biochemie , Freie Universität Berlin , Thielallee 63 , D-14195 Berlin , Germany
| | - Sumaira Pervaiz
- Institut für Chemie und Biochemie , Freie Universität Berlin , Thielallee 63 , D-14195 Berlin , Germany
| | - Yasmin S. Razzaque
- Institut für Chemie und Biochemie , Freie Universität Berlin , Thielallee 63 , D-14195 Berlin , Germany
| | - Tobias Stauber
- Institut für Chemie und Biochemie , Freie Universität Berlin , Thielallee 63 , D-14195 Berlin , Germany
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Purkayastha S, Stokes M, Bell KR. Autonomic nervous system dysfunction in mild traumatic brain injury: a review of related pathophysiology and symptoms. Brain Inj 2019; 33:1129-1136. [DOI: 10.1080/02699052.2019.1631488] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Sushmita Purkayastha
- Department of Applied Physiology and Wellness, Simmons School of Education and Human Development, Southern Methodist University, Dallas, TX, USA
- Department of Physical Medicine and Rehabilitation, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Mathew Stokes
- Department of Pediatrics/Division of Pediatric Neurology & Pain Management, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kathleen R Bell
- Department of Physical Medicine and Rehabilitation, University of Texas Southwestern Medical Center, Dallas, TX, USA
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