1
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Xu J, Yang R, Li J, Wang L, Cohen M, Simeone DM, Costa M, Wu XR. DNMT3A/ miR-129-2-5p/Rac1 Is an Effector Pathway for SNHG1 to Drive Stem-Cell-like and Invasive Behaviors of Advanced Bladder Cancer Cells. Cancers (Basel) 2022; 14:4159. [PMID: 36077697 PMCID: PMC9454896 DOI: 10.3390/cancers14174159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/20/2022] [Accepted: 08/25/2022] [Indexed: 11/16/2022] Open
Abstract
The stem-cell-like behavior of cancer cells plays a central role in tumor heterogeneity and invasion and correlates closely with drug resistance and unfavorable clinical outcomes. However, the molecular underpinnings of cancer cell stemness remain incompletely defined. Here, we show that SNHG1, a long non-coding RNA that is over-expressed in ~95% of human muscle-invasive bladder cancers (MIBCs), induces stem-cell-like sphere formation and the invasion of cultured bladder cancer cells by upregulating Rho GTPase, Rac1. We further show that SNHG1 binds to DNA methylation transferase 3A protein (DNMT3A), and tethers DNMT3A to the promoter of miR-129-2, thus hyper-methylating and repressing miR-129-2-5p transcription. The reduced binding of miR-129-2 to the 3'-UTR of Rac1 mRNA leads to the stabilization of Rac1 mRNA and increased levels of Rac1 protein, which then stimulates MIBC cell sphere formation and invasion. Analysis of the Human Protein Atlas shows that a high expression of Rac1 is strongly associated with poor survival in patients with MIBC. Our data strongly suggest that the SNHG1/DNMT3A/miR-129-2-5p/Rac1 effector pathway drives stem-cell-like and invasive behaviors in MIBC, a deadly form of bladder cancer. Targeting this pathway, alone or in combination with platinum-based therapy, may reduce chemoresistance and improve longer-term outcomes in MIBC patients.
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Affiliation(s)
- Jiheng Xu
- Department of Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Rui Yang
- Department of Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Jingxia Li
- Department of Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Lidong Wang
- Department of Surgery, New York University School of Medicine, New York, NY 10016, USA
| | - Mitchell Cohen
- Department of Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Diane M. Simeone
- Department of Surgery, New York University School of Medicine, New York, NY 10016, USA
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Max Costa
- Department of Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Xue-Ru Wu
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
- Department of Urology, New York University School of Medicine, New York, NY 10016, USA
- Veterans Affairs New York Harbor Healthcare System, Manhattan Campus, New York, NY 10010, USA
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2
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Velnati S, Centonze S, Girivetto F, Capello D, Biondi RM, Bertoni A, Cantello R, Ragnoli B, Malerba M, Graziani A, Baldanzi G. Identification of Key Phospholipids That Bind and Activate Atypical PKCs. Biomedicines 2021; 9:biomedicines9010045. [PMID: 33419210 PMCID: PMC7825596 DOI: 10.3390/biomedicines9010045] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/30/2020] [Accepted: 01/01/2021] [Indexed: 12/02/2022] Open
Abstract
PKCζ and PKCι/λ form the atypical protein kinase C subgroup, characterised by a lack of regulation by calcium and the neutral lipid diacylglycerol. To better understand the regulation of these kinases, we systematically explored their interactions with various purified phospholipids using the lipid overlay assays, followed by kinase activity assays to evaluate the lipid effects on their enzymatic activity. We observed that both PKCζ and PKCι interact with phosphatidic acid and phosphatidylserine. Conversely, PKCι is unique in binding also to phosphatidylinositol-monophosphates (e.g., phosphatidylinositol 3-phosphate, 4-phosphate, and 5-phosphate). Moreover, we observed that phosphatidylinositol 4-phosphate specifically activates PKCι, while both isoforms are responsive to phosphatidic acid and phosphatidylserine. Overall, our results suggest that atypical Protein kinase C (PKC) localisation and activity are regulated by membrane lipids distinct from those involved in conventional PKCs and unveil a specific regulation of PKCι by phosphatidylinositol-monophosphates.
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Affiliation(s)
- Suresh Velnati
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- Center for Translational Research on Allergic and Autoimmune Diseases (CAAD), University of Piemonte Orientale, 28100 Novara, Italy
- Correspondence:
| | - Sara Centonze
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- Center for Translational Research on Allergic and Autoimmune Diseases (CAAD), University of Piemonte Orientale, 28100 Novara, Italy
| | - Federico Girivetto
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- Center for Translational Research on Allergic and Autoimmune Diseases (CAAD), University of Piemonte Orientale, 28100 Novara, Italy
| | - Daniela Capello
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- UPO Biobank, University of Piemonte Orientale, 28100 Novara, Italy
| | - Ricardo M. Biondi
- Department of Internal Medicine 1, Goethe University Hospital Frankfurt, 60590 Frankfurt, Germany;
- Biomedicine Research Institute of Buenos Aires—CONICET—Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina
| | - Alessandra Bertoni
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
| | - Roberto Cantello
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
| | | | - Mario Malerba
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- Respiratory Unit, Sant’Andrea Hospital, 13100 Vercelli, Italy;
| | - Andrea Graziani
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, 10126 Turin, Italy;
- Division of Oncology, Università Vita-Salute San Raffaele, 20132 Milan, Italy
| | - Gianluca Baldanzi
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- Center for Translational Research on Allergic and Autoimmune Diseases (CAAD), University of Piemonte Orientale, 28100 Novara, Italy
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3
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Catacuzzeno L, Sforna L, Esposito V, Limatola C, Franciolini F. Ion Channels in Glioma Malignancy. Rev Physiol Biochem Pharmacol 2020; 181:223-267. [DOI: 10.1007/112_2020_44] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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4
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Arranz-Nicolás J, Mérida I. Biological regulation of diacylglycerol kinases in normal and neoplastic tissues: New opportunities for cancer immunotherapy. Adv Biol Regul 2020; 75:100663. [PMID: 31706704 DOI: 10.1016/j.jbior.2019.100663] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/20/2019] [Accepted: 09/30/2019] [Indexed: 06/10/2023]
Abstract
In the recent years, the arsenal of anti-cancer therapies has evolved to target T lymphocytes and restore their capacity to destroy tumor cells. However, the clinical success is limited, with a large number of patients that never responds and others that ultimately develop resistances. Overcoming the hypofunctional state imposed by solid tumors to T cells has revealed critical but challenging due to the complex strategies that tumors employ to evade the immune system. The Diacylglycerol kinases (DGK) limit DAG-dependent functions in T lymphocytes and their upregulation in tumor-infiltrating T lymphocytes contribute to limit T cell cytotoxic potential. DGK blockade could reinstate T cell attack on tumors, limiting at the same time tumor cell growth, thanks to the DGK positive input into several oncogenic pathways. In this review we summarize the latest findings regarding the regulation of specific DGK isoforms in healthy and anergic T lymphocytes, as well as their contribution to oncogenic phenotypes. We will also revise the latest advances in the search for pharmacological inhibitors and their potential as anti-cancer agents, either alone or in combination with immunomodulatory agents.
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Affiliation(s)
- Javier Arranz-Nicolás
- Department of Immunology and Oncology, National Center for Biotechnology (CNB-CSIC), Darwin 3, UAM Campus de Cantoblanco, 28049, Madrid, Spain
| | - Isabel Mérida
- Department of Immunology and Oncology, National Center for Biotechnology (CNB-CSIC), Darwin 3, UAM Campus de Cantoblanco, 28049, Madrid, Spain.
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5
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Diacylglycerol kinase control of protein kinase C. Biochem J 2019; 476:1205-1219. [DOI: 10.1042/bcj20180620] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/29/2019] [Accepted: 04/01/2019] [Indexed: 12/27/2022]
Abstract
Abstract
The diacylglycerol kinases (DGK) are lipid kinases that transform diacylglycerol (DAG) into phosphatidic acid (PA) in a reaction that terminates DAG-based signals. DGK provide negative regulation to conventional and novel protein kinase C (PKC) enzymes, limiting local DAG availability in a tissue- and subcellular-restricted manner. Defects in the expression/activity of certain DGK isoforms contribute substantially to cognitive impairment and mental disorders. Abnormal DGK overexpression in tumors facilitates invasion and resistance to chemotherapy preventing tumor immune destruction by tumor-infiltrating lymphocytes. Effective translation of these findings into therapeutic approaches demands a better knowledge of the physical and functional interactions between the DGK and PKC families. DGKζ is abundantly expressed in the nervous and immune system, where physically and functionally interacts with PKCα. The latest discoveries suggest that PDZ-mediated interaction facilitates spatial restriction of PKCα by DGKζ at the cell–cell contact sites in a mechanism where the two enzymes regulate each other. In T lymphocytes, DGKζ interaction with Sorting Nexin 27 (SNX27) guarantees the basal control of PKCα activation. SNX27 is a trafficking component required for normal brain function whose deficit has been linked to Alzheimer's disease (AD) pathogenesis. The enhanced PKCα activation as the result of SNX27 silencing in T lymphocytes aligns with the recent correlation found between gain-of-function PKCα mutations and AD and suggests that disruption of the mechanisms that provides a correct spatial organization of DGKζ and PKCα may lie at the basis of immune and neuronal synapse impairment.
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6
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Caramia M, Sforna L, Franciolini F, Catacuzzeno L. The Volume-Regulated Anion Channel in Glioblastoma. Cancers (Basel) 2019; 11:cancers11030307. [PMID: 30841564 PMCID: PMC6468384 DOI: 10.3390/cancers11030307] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 02/22/2019] [Accepted: 02/26/2019] [Indexed: 01/02/2023] Open
Abstract
Malignancy of glioblastoma multiforme (GBM), the most common and aggressive form of human brain tumor, strongly depends on its enhanced cell invasion and death evasion which make surgery and accompanying therapies highly ineffective. Several ion channels that regulate membrane potential, cytosolic Ca2+ concentration and cell volume in GBM cells play significant roles in sustaining these processes. Among them, the volume-regulated anion channel (VRAC), which mediates the swelling-activated chloride current (IClswell) and is highly expressed in GBM cells, arguably plays a major role. VRAC is primarily involved in reestablishing the original cell volume that may be lost under several physiopathological conditions, but also in sustaining the shape and cell volume changes needed for cell migration and proliferation. While experimentally VRAC is activated by exposing cells to hypotonic solutions that cause the increase of cell volume, in vivo it is thought to be controlled by several different stimuli and modulators. In this review we focus on our recent work showing that two conditions normally occurring in pathological GBM tissues, namely high serum levels and severe hypoxia, were both able to activate VRAC, and their activation was found to promote cell migration and resistance to cell death, both features enhancing GBM malignancy. Also, the fact that the signal transduction pathway leading to VRAC activation appears to involve GBM specific intracellular components, such as diacylglicerol kinase and phosphatidic acid, reportedly not involved in the activation of VRAC in healthy tissues, is a relevant finding. Based on these observations and the impact of VRAC in the physiopathology of GBM, targeting this channel or its intracellular regulators may represent an effective strategy to contrast this lethal tumor.
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Affiliation(s)
- Martino Caramia
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia 06123, Italy.
| | - Luigi Sforna
- Department of Experimental Medicine, University of Perugia, Perugia 06132, Italy.
| | - Fabio Franciolini
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia 06123, Italy.
| | - Luigi Catacuzzeno
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia 06123, Italy.
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7
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Baldanzi G, Bettio V, Malacarne V, Graziani A. Diacylglycerol Kinases: Shaping Diacylglycerol and Phosphatidic Acid Gradients to Control Cell Polarity. Front Cell Dev Biol 2016; 4:140. [PMID: 27965956 PMCID: PMC5126041 DOI: 10.3389/fcell.2016.00140] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 11/14/2016] [Indexed: 12/24/2022] Open
Abstract
Diacylglycerol kinases (DGKs) terminate diacylglycerol (DAG) signaling and promote phosphatidic acid (PA) production. Isoform specific regulation of DGKs activity and localization allows DGKs to shape the DAG and PA gradients. The capacity of DGKs to constrain the areas of DAG signaling is exemplified by their role in defining the contact interface between T cells and antigen presenting cells: the immune synapse. Upon T cell receptor engagement, both DGK α and ζ metabolize DAG at the immune synapse thus constraining DAG signaling. Interestingly, their activity and localization are not fully redundant because DGKζ activity metabolizes the bulk of DAG in the cell, whereas DGKα limits the DAG signaling area localizing specifically at the periphery of the immune synapse. When DGKs terminate DAG signaling, the local PA production defines a new signaling domain, where PA recruits and activates a second wave of effector proteins. The best-characterized example is the role of DGKs in protrusion elongation and cell migration. Indeed, upon growth factor stimulation, several DGK isoforms, such as α, ζ, and γ, are recruited and activated at the plasma membrane. Here, local PA production controls cell migration by finely modulating cytoskeletal remodeling and integrin recycling. Interestingly, DGK-produced PA also controls the localization and activity of key players in cell polarity such as aPKC, Par3, and integrin β1. Thus, T cell polarization and directional migration may be just two instances of the general contribution of DGKs to the definition of cell polarity by local specification of membrane identity signaling.
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Affiliation(s)
- Gianluca Baldanzi
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Institute for Research and Cure of Autoimmune DiseasesNovara, Italy
| | - Valentina Bettio
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Institute for Research and Cure of Autoimmune DiseasesNovara, Italy
| | - Valeria Malacarne
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Division of Experimental Oncology, School of Medicine, University Vita e Salute San RaffaeleMilan, Italy
| | - Andrea Graziani
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Division of Experimental Oncology, School of Medicine, University Vita e Salute San RaffaeleMilan, Italy
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8
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Kamerbeek CB, Mateos MV, Vallés AS, Pediconi MF, Barrantes FJ, Borroni V. Diacylglycerol levels modulate the cellular distribution of the nicotinic acetylcholine receptor. Int J Biochem Cell Biol 2016; 74:1-11. [PMID: 26898898 DOI: 10.1016/j.biocel.2016.02.010] [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: 04/18/2015] [Revised: 02/03/2016] [Accepted: 02/15/2016] [Indexed: 10/22/2022]
Abstract
Diacylglycerol (DAG), a second messenger involved in different cell signaling cascades, activates protein kinase C (PKC) and D (PKD), among other kinases. The present work analyzes the effects resulting from the alteration of DAG levels on neuronal and muscle nicotinic acetylcholine receptor (AChR) distribution. We employ CHO-K1/A5 cells, expressing adult muscle-type AChR in a stable manner, and hippocampal neurons, which endogenously express various subtypes of neuronal AChR. CHO-K1/A5 cells treated with dioctanoylglycerol (DOG) for different periods showed augmented AChR cell surface levels at short incubation times (30min-4h) whereas at longer times (18h) the AChR was shifted to intracellular compartments. Similarly, in cultured hippocampal neurons surface AChR levels increased as a result of DOG incubation for 4h. Inhibition of endogenous DAG catabolism produced changes in AChR distribution similar to those induced by DOG treatment. Specific enzyme inhibitors and Western blot assays revealed that DAGs exert their effect on AChR distribution through the modulation of the activity of classical PKC (cPKC), novel PKC (nPKC) and PKD activity.
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Affiliation(s)
- Constanza B Kamerbeek
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga km 7, 8000 Bahía Blanca, Argentina
| | - Melina V Mateos
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga km 7, 8000 Bahía Blanca, Argentina
| | - Ana S Vallés
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga km 7, 8000 Bahía Blanca, Argentina
| | - María F Pediconi
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga km 7, 8000 Bahía Blanca, Argentina
| | - Francisco J Barrantes
- Laboratory of Molecular Neurobiology, Institute for Biomedical Research UCA-CONICET, Faculty of Medical Sciences, Av. Alicia Moreau de Justo 1600, C1107AFF Buenos Aires, Argentina
| | - Virginia Borroni
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga km 7, 8000 Bahía Blanca, Argentina.
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9
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Steffen A, Stradal TEB, Rottner K. Signalling Pathways Controlling Cellular Actin Organization. Handb Exp Pharmacol 2016; 235:153-178. [PMID: 27757765 DOI: 10.1007/164_2016_35] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The actin cytoskeleton is essential for morphogenesis and virtually all types of cell shape changes. Reorganization is per definition driven by continuous disassembly and re-assembly of actin filaments, controlled by major, ubiquitously operating machines. These are specifically employed by the cell to tune its activities in accordance with respective environmental conditions or to satisfy specific needs.Here we sketch some fundamental signalling pathways established to contribute to the reorganization of specific actin structures at the plasma membrane. Rho-family GTPases are at the core of these pathways, and dissection of their precise contributions to actin reorganization in different cell types and tissues will thus continue to improve our understanding of these important signalling nodes. Furthermore, we will draw your attention to the emerging theme of actin reorganization on intracellular membranes, its functional relation to Rho-GTPase signalling, and its relevance for the exciting phenomenon autophagy.
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Affiliation(s)
- Anika Steffen
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Theresia E B Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
| | - Klemens Rottner
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.,Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106, Braunschweig, Germany
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10
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Ard R, Mulatz K, Pomoransky JL, Parks RJ, Trinkle-Mulcahy L, Bell JC, Gee SH. Regulation of Macropinocytosis by Diacylglycerol Kinase ζ. PLoS One 2015; 10:e0144942. [PMID: 26701304 PMCID: PMC4689489 DOI: 10.1371/journal.pone.0144942] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 11/25/2015] [Indexed: 12/02/2022] Open
Abstract
Macropinosomes arise from the closure of plasma membrane ruffles to bring about the non-selective uptake of nutrients and solutes into cells. The morphological changes underlying ruffle formation and macropinosome biogenesis are driven by actin cytoskeleton rearrangements under the control of the Rho GTPase Rac1. We showed previously that Rac1 is activated by diacylglycerol kinase ζ (DGKζ), which phosphorylates diacylglycerol to yield phosphatidic acid. Here, we show DGKζ is required for optimal macropinocytosis induced by growth factor stimulation of mouse embryonic fibroblasts. Time-lapse imaging of live cells and quantitative analysis revealed DGKζ was associated with membrane ruffles and nascent macropinosomes. Macropinocytosis was attenuated in DGKζ-null cells, as determined by live imaging and vaccinia virus uptake experiments. Moreover, macropinosomes that did form in DGKζ-null cells were smaller than those found in wild type cells. Rescue of this defect required DGKζ catalytic activity, consistent with it also being required for Rac1 activation. A constitutively membrane bound DGKζ mutant substantially increased the size of macropinosomes and potentiated the effect of a constitutively active Rac1 mutant on macropinocytosis. Collectively, our results suggest DGKζ functions in concert with Rac1 to regulate macropinocytosis.
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Affiliation(s)
- Ryan Ard
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Rd, Ottawa, ON, K1H 8M5, Canada
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
| | - Kirk Mulatz
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Rd, Ottawa, ON, K1H 8M5, Canada
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
| | - Julia L. Pomoransky
- Centre for Innovative Cancer Research, Ottawa Hospital Research Institute, 503 Smyth Road, 3rd floor ORCC, Ottawa, ON, K1H 1C4, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Robin J. Parks
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada
| | - Laura Trinkle-Mulcahy
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Rd, Ottawa, ON, K1H 8M5, Canada
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON, Canada
| | - John C. Bell
- Centre for Innovative Cancer Research, Ottawa Hospital Research Institute, 503 Smyth Road, 3rd floor ORCC, Ottawa, ON, K1H 1C4, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Stephen H. Gee
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Rd, Ottawa, ON, K1H 8M5, Canada
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
- * E-mail:
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11
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Baldanzi G, Graziani A. Physiological Signaling and Structure of the HGF Receptor MET. Biomedicines 2014; 3:1-31. [PMID: 28536396 PMCID: PMC5344233 DOI: 10.3390/biomedicines3010001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/09/2014] [Indexed: 12/13/2022] Open
Abstract
The "hepatocyte growth factor" also known as "scatter factor", is a multifunctional cytokine with the peculiar ability of simultaneously triggering epithelial cell proliferation, movement and survival. The combination of those proprieties results in the induction of an epithelial to mesenchymal transition in target cells, fundamental for embryogenesis but also exploited by tumor cells during metastatization. The hepatocyte growth factor receptor, MET, is a proto-oncogene and a prototypical transmembrane tyrosine kinase receptor. Inhere we discuss the MET molecular structure and the hepatocyte growth factor driven physiological signaling which coordinates epithelial proliferation, motility and morphogenesis.
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Affiliation(s)
- Gianluca Baldanzi
- Department Translational Medicine, University Piemonte Orientale, via Solaroli 17, 28100 Novara, Italy.
| | - Andrea Graziani
- Department Translational Medicine, University Piemonte Orientale, via Solaroli 17, 28100 Novara, Italy.
- Università Vita-Salute San Raffaele, via Olgettina 58, 20132 Milano, Italy.
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12
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Rainero E, Cianflone C, Porporato PE, Chianale F, Malacarne V, Bettio V, Ruffo E, Ferrara M, Benecchia F, Capello D, Paster W, Locatelli I, Bertoni A, Filigheddu N, Sinigaglia F, Norman JC, Baldanzi G, Graziani A. The diacylglycerol kinase α/atypical PKC/β1 integrin pathway in SDF-1α mammary carcinoma invasiveness. PLoS One 2014; 9:e97144. [PMID: 24887021 PMCID: PMC4041662 DOI: 10.1371/journal.pone.0097144] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 04/15/2014] [Indexed: 12/11/2022] Open
Abstract
Diacylglycerol kinase α (DGKα), by phosphorylating diacylglycerol into phosphatidic acid, provides a key signal driving cell migration and matrix invasion. We previously demonstrated that in epithelial cells activation of DGKα activity promotes cytoskeletal remodeling and matrix invasion by recruiting atypical PKC at ruffling sites and by promoting RCP-mediated recycling of α5β1 integrin to the tip of pseudopods. In here we investigate the signaling pathway by which DGKα mediates SDF-1α-induced matrix invasion of MDA-MB-231 invasive breast carcinoma cells. Indeed we showed that, following SDF-1α stimulation, DGKα is activated and localized at cell protrusion, thus promoting their elongation and mediating SDF-1α induced MMP-9 metalloproteinase secretion and matrix invasion. Phosphatidic acid generated by DGKα promotes localization at cell protrusions of atypical PKCs which play an essential role downstream of DGKα by promoting Rac-mediated protrusion elongation and localized recruitment of β1 integrin and MMP-9. We finally demonstrate that activation of DGKα, atypical PKCs signaling and β1 integrin are all essential for MDA-MB-231 invasiveness. These data indicates the existence of a SDF-1α induced DGKα - atypical PKC - β1 integrin signaling pathway, which is essential for matrix invasion of carcinoma cells.
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Affiliation(s)
- Elena Rainero
- Integrin Biology Laboratory, Beatson Institute for Cancer Research, Glasgow, Scotland, United Kingdom
| | - Cristina Cianflone
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | | | - Federica Chianale
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Valeria Malacarne
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Valentina Bettio
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Elisa Ruffo
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Michele Ferrara
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Fabio Benecchia
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Daniela Capello
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Wolfgang Paster
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Irene Locatelli
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Alessandra Bertoni
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Nicoletta Filigheddu
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Fabiola Sinigaglia
- Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Jim C. Norman
- Integrin Biology Laboratory, Beatson Institute for Cancer Research, Glasgow, Scotland, United Kingdom
| | - Gianluca Baldanzi
- Integrin Biology Laboratory, Beatson Institute for Cancer Research, Glasgow, Scotland, United Kingdom
| | - Andrea Graziani
- Integrin Biology Laboratory, Beatson Institute for Cancer Research, Glasgow, Scotland, United Kingdom
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ASAP1 mediates the invasive phenotype of human laryngeal squamous cell carcinoma to affect survival prognosis. Oncol Rep 2014; 31:2676-82. [PMID: 24788532 DOI: 10.3892/or.2014.3150] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 03/24/2014] [Indexed: 11/05/2022] Open
Abstract
ASAP1 helps regulate cellular structures such as actin cytoskeletal remodeling and focal adhesions that have a pivotal function in tumor progression. Overexpression of ASAP1 has proven to be a malignant indicator for a variety of tumors. To further determine the potential involvement of ASAP1 in laryngeal squamous cell carcinoma (LSCC), we evaluated the expression levels of ASAP1 by quantitative real-time reverse-transcriptase polymerase chain reaction (qRT-PCR) and immunohistochemistry in tissue samples of 64 LSCC patients. We then analyzed and correlated the results with clinicopathological features. Furthermore, we used small interfering RNA (siRNA) to inhibit ASAP1 expression in vitro. The potential function of ASAP1 in invasiveness was evaluated in the Hep-2 LSCC cell line. Kaplan-Meier method was utilized to determine the association of ASAP1 expression with survival of patients. We showed that ASAP1 was upregulated in primary LSCC tumors and was correlated with lymph node metastasis and clinical tumor stage. Similarly, higher levels of ASAP1 were detected in the Hep-2 cell line compared to the 16 human bronchial epithelial (16HBE) cell line. ASAP1 expression was downregulated by lentiviral vector transfection containing siRNA in vitro. The invasive potential of these cells was found to be significantly suppressed, while expression levels of Rac1 and Cdc42 positively correlated with the inhibition of ASAP1 expression. In Kaplan-Meier overall survival curves, higher ASAP1 mRNA levels were found to be associated with a shorter progression-free survival trend. Based on these results, ASAP1 appears to contribute to the malignant mechanism of LSCC and may represent a significant prognostic marker for LSCC patients.
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Cai K, Mulatz K, Ard R, Nguyen T, Gee SH. Increased diacylglycerol kinase ζ expression in human metastatic colon cancer cells augments Rho GTPase activity and contributes to enhanced invasion. BMC Cancer 2014; 14:208. [PMID: 24646293 PMCID: PMC3995506 DOI: 10.1186/1471-2407-14-208] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 03/12/2014] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Unraveling the signaling pathways responsible for the establishment of a metastatic phenotype in carcinoma cells is critically important for understanding the pathology of cancer. The acquisition of cell motility is a key property of metastatic tumor cells and is a prerequisite for invasion. Rho GTPases regulate actin cytoskeleton reorganization and the cellular responses required for cell motility and invasion. Diacylglycerol kinase ζ (DGKζ), an enzyme that phosphorylates diacylglycerol to yield phosphatidic acid, regulates the activity of the Rho GTPases Rac1 and RhoA. DGKζ mRNA is highly expressed in several different colon cancer cell lines, as well as in colon cancer tissue relative to normal colonic epithelium, and thus may contribute to the metastatic process. METHODS To investigate potential roles of DGKζ in cancer metastasis, a cellular, isogenic model of human colorectal cancer metastatic transition was used. DGKζ protein levels, Rac1 and RhoA activity, and PAK phosphorylation were measured in the non-metastatic SW480 adenocarcinoma cell line and its highly metastatic variant, the SW620 line. The effect of DGKζ silencing on Rho GTPase activity and invasion through Matrigel-coated Transwell inserts was studied in SW620 cells. Invasiveness was also measured in PC-3 prostate cancer and MDA-MB-231 breast cancer cells depleted of DGKζ. RESULTS DGKζ protein levels were elevated approximately 3-fold in SW620 cells compared to SW480 cells. There was a concomitant increase in active Rac1 in SW620 cells, as well as substantial increases in the expression and phosphorylation of the Rac1 effector PAK1. Similarly, RhoA activity and expression were increased in SW620 cells. Knockdown of DGKζ expression in SW620 cells by shRNA-mediated silencing significantly reduced Rac1 and RhoA activity and attenuated the invasiveness of SW620 cells in vitro. DGKζ silencing in highly metastatic MDA-MB-231 breast cancer cells and PC-3 prostate cancer cells also significantly attenuated their invasiveness. CONCLUSION Elevated DGKζ expression contributes to increased Rho GTPase activation and the enhanced motility of metastatic cancer cells. These findings warrant further investigation of the clinical relevance of DGKζ upregulation in colon and other cancers. Interfering with DGKζ function could provide a means of inhibiting invasion and metastasis.
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Affiliation(s)
| | | | | | | | - Stephen H Gee
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Rd, Ottawa, ON K1H 8 M5, Canada.
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15
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Catacuzzeno L, Michelucci A, Sforna L, Aiello F, Sciaccaluga M, Fioretti B, Castigli E, Franciolini F. Identification of key signaling molecules involved in the activation of the swelling-activated chloride current in human glioblastoma cells. J Membr Biol 2013; 247:45-55. [PMID: 24240542 DOI: 10.1007/s00232-013-9609-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 10/14/2013] [Indexed: 12/17/2022]
Abstract
The swelling-activated chloride current (I Cl,Vol) is abundantly expressed in glioblastoma (GBM) cells, where it controls cell volume and invasive migration. The transduction pathway mediating I Cl,Vol activation in GBM cells is, however, poorly understood. By means of pharmacological and electrophysiological approaches, on GL-15 human GBM cells we found that I Cl,Vol activation by hypotonic swelling required the activity of a U73122-sensitive phospholipase C (PLC). I Cl,Vol activation could also be induced by the membrane-permeable diacylglycerol (DAG) analog OAG. In contrast, neither calcium (Ca(2+)) chelation by BAPTA-AM nor changes in PKC activity were able to affect I Cl,Vol activation by hypotonic swelling. We further found that R59022, an inhibitor of diacylglycerol kinase (DGK), reverted I Cl,Vol activation, suggesting the involvement of phosphatidic acid. In addition, I Cl,Vol activation required the activity of a EHT1864-sensitive Rac1 small GTPase and the resulting actin polymerization, as I Cl,Vol activation was prevented by cytochalasin B. We finally show that I Cl,Vol can be activated by the promigratory fetal calf serum in a PLC- and DGK-dependent manner. This observation is potentially relevant because blood serum can likely come in contact with glioblastoma cells in vivo as a result of the tumor-related partial breakdown of the blood-brain barrier. Given the relevance of I Cl,Vol in GBM cell volume regulation and invasiveness, the several key signaling molecules found in this study to be involved in the activation of the I Cl,Vol may represent potential therapeutic targets against this lethal cancer.
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Affiliation(s)
- Luigi Catacuzzeno
- Dipartimento di Biologia Cellulare e Ambientale, Universita' di Perugia, Via Pascoli 1, 06123, Perugia, Italy,
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16
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Meyer G, Leipprandt J, Xie J, Aupperlee MD, Haslam SZ. A potential role of progestin-induced laminin-5/α6-integrin signaling in the formation of side branches in the mammary gland. Endocrinology 2012; 153:4990-5001. [PMID: 22910029 PMCID: PMC3512027 DOI: 10.1210/en.2012-1518] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 07/31/2012] [Indexed: 11/19/2022]
Abstract
Mammary organoids from adult mice produce tubules, analogous to mammary ducts in vivo, in response to hepatocyte growth factor (HGF) when cultured in collagen gels. The combination of HGF plus progestin (R5020) causes reduced tubule number and length. We hypothesized that the inhibitory effect on tubulogenesis was due to progestin-mediated alteration of HGF/c-Met signaling. Using molecular inhibitors and short hairpin RNA, it was determined that HGF activation of Ras-related C3 botulinum toxin substrate (Rac1) was required for the formation of cytoplasmic extensions, the first step of tubulogenesis, and that Rac1 activity was Src kinase (Src) and focal adhesion kinase (FAK) dependent. The highly novel finding was that R5020 reduced tubulogenesis by up-regulating and increasing extracellular laminin and α6-integrin ligation to reduce activation of the Src, focal adhesion kinase, and Rac1 pathway. Receptor activator of nuclear factor-κB ligand, another progesterone-induced paracrine factor, did not replicate this effect of R5020. The inhibitory effect of R5020 on tubulogenesis was likely mediated through progesterone receptor (PR) isoform A (PRA), because PRA is the predominant PR isoform expressed in the organoids, and the progestin-induced effect was prevented by the PR antagonist RU486. These results provide a plausible mechanism that explains progestin/PRA-mediated blunting of HGF-induced tubulogenesis in vitro and is proposed to be relevant to progesterone/PRA-induced side-branching in vivo during pregnancy.
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Affiliation(s)
- Gabriele Meyer
- Department of Physiology and Breast Cancer and the Environment Research Center, Michigan State University, East Lansing, Michigan 48824, USA
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17
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Rainero E, Caswell PT, Muller PAJ, Grindlay J, McCaffrey MW, Zhang Q, Wakelam MJO, Vousden KH, Graziani A, Norman JC. Diacylglycerol kinase α controls RCP-dependent integrin trafficking to promote invasive migration. ACTA ACUST UNITED AC 2012; 196:277-95. [PMID: 22270919 PMCID: PMC3265946 DOI: 10.1083/jcb.201109112] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phosphatidic acid generation by DGK-α is essential for the localization of Rab11-coupling protein to invasive pseudopods and subsequent invasive migration by tumor cells. Inhibition of αvβ3 integrin or expression of oncogenic mutants of p53 promote invasive cell migration by enhancing endosomal recycling of α5β1 integrin under control of the Rab11 effector Rab-coupling protein (RCP). In this paper, we show that diacylglycerol kinase α (DGK-α), which phosphorylates diacylglycerol to phosphatidic acid (PA), was required for RCP to be mobilized to and tethered at the tips of invasive pseudopods and to allow RCP-dependent α5β1 recycling and the resulting invasiveness of tumor cells. Expression of a constitutive-active mutant of DGK-α drove RCP-dependent invasion in the absence of mutant p53 expression or αvβ3 inhibition, and conversely, an RCP mutant lacking the PA-binding C2 domain was not capable of being tethered at pseudopod tips. These data demonstrate that generation of PA downstream of DGK-α is essential to connect expression of mutant p53s or inhibition of αvβ3 to RCP and for this Rab11 effector to drive the trafficking of α5β1 that is required for tumor cell invasion through three-dimensional matrices.
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Affiliation(s)
- Elena Rainero
- Beatson Institute for Cancer Research, G61 1BD Glasgow, Scotland, UK
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18
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Shulga YV, Topham MK, Epand RM. Regulation and functions of diacylglycerol kinases. Chem Rev 2011; 111:6186-208. [PMID: 21800853 DOI: 10.1021/cr1004106] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yulia V Shulga
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
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19
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Diacylglycerol kinase α mediates 17-β-estradiol-induced proliferation, motility, and anchorage-independent growth of Hec-1A endometrial cancer cell line through the G protein-coupled estrogen receptor GPR30. Cell Signal 2011; 23:1988-96. [PMID: 21802511 DOI: 10.1016/j.cellsig.2011.07.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 07/14/2011] [Accepted: 07/14/2011] [Indexed: 12/31/2022]
Abstract
Increased levels of endogenous and/or exogenous estrogens are one of the well known risk factors of endometrial cancer. Diacylglycerol kinases (DGKs) are a family of enzymes which phosphorylate diacylglycerol (DAG) to produce phosphatidic acid (PA), thus turning off and on DAG-mediated and PA-mediated signaling pathways, respectively. DGK α activity is stimulated by growth factors and oncogenes and is required for chemotactic, proliferative, and angiogenic signaling in vitro. Herein, using either specific siRNAs or the pharmacological inhibitor R59949, we demonstrate that DGK α activity is required for 17-β-estradiol (E2)-induced proliferation, motility, and anchorage-independent growth of Hec-1A endometrial cancer cell line. Impairment of DGK α activity also influences basal cell proliferation and growth in soft agar of Hec-1A, while it has no effects on basal cell motility. Moreover, we show that DGK α activity induced by E2, as well as its observed effects, are mediated by the G protein-coupled estrogen receptor GPR30 (GPER). These findings suggest that DGK α may be a potential target in endometrial cancer therapy.
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20
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Baldanzi G, Pietronave S, Locarno D, Merlin S, Porporato P, Chianale F, Filigheddu N, Cantelmo AR, Albini A, Graziani A, Prat M. Diacylglycerol kinases are essential for hepatocyte growth factor-dependent proliferation and motility of Kaposi's sarcoma cells. Cancer Sci 2011; 102:1329-36. [PMID: 21477072 DOI: 10.1111/j.1349-7006.2011.01953.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Hepatocyte growth factor (HGF) is involved in the pathogenesis of Kaposi's sarcoma (KS), the most frequent neoplasia in patients with AIDS, characterized by proliferating spindle cells, infiltrating inflammatory cells, angiogenesis, edema, and invasiveness. In vitro, this factor sustains the biological behavior of KS derived cells, after activation of its receptor and the downstream MAPK and AKT signals. In other cell types, namely endothelial and epithelial cells, movement, proliferation, and survival stimulated by HGF and other growth factors and cytokines depend on diacylglycerol kinases (DGK). In an effort to identify new intracellular transducers operative in KS cells, which could represent therapeutic targets, we investigated the role of DGK in KS cell movement and proliferation by treating cells with the DGK pharmacological inhibitor R59949. We report that R59949 strongly inhibits HGF-induced KS motility, proliferation, and anchorage-independent growth with only a partial effect on cell adhesion and spreading. R59949 does not affect cell survival, HGF receptor activation, or the classical MAPK and AKT signalling pathways. Furthermore, we carried out an siRNA screen to characterize the DGK isoforms involved in KS motility and anchorage independent growth. Our data indicate a strong involvement of DGK-δ in KS motility and of DGK-ι in anchorage-independent growth. These results indicate that DGK inhibition is sufficient to impair in vitro KS cell proliferation and movement and suggest that selected DGK represent new pharmacological targets to interfere with the malignant properties of KS, independently from the well-known RAS/MAPK and PI3K/AKT pathways.
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Affiliation(s)
- Gianluca Baldanzi
- Department of Experimental and Clinical Medicine, Università del Piemonte Orientale Amedeo Avogadro, Novara IRCCS Multimedica, Milan, Italy
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21
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Diacylglycerol kinase alpha mediates HGF-induced Rac activation and membrane ruffling by regulating atypical PKC and RhoGDI. Proc Natl Acad Sci U S A 2010; 107:4182-7. [PMID: 20160093 DOI: 10.1073/pnas.0908326107] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Diacylglycerol kinases (DGKs) convert diacylglycerol (DAG) into phosphatidic acid (PA), acting as molecular switches between DAG- and PA-mediated signaling. We previously showed that Src-dependent activation and plasma membrane recruitment of DGKalpha are required for growth-factor-induced cell migration and ruffling, through the control of Rac small-GTPase activation and plasma membrane localization. Herein we unveil a signaling pathway through which DGKalpha coordinates the localization of Rac. We show that upon hepatocyte growth-factor stimulation, DGKalpha, by producing PA, provides a key signal to recruit atypical PKCzeta/iota (aPKCzeta/iota) in complex with RhoGDI and Rac at ruffling sites of colony-growing epithelial cells. Then, DGKalpha-dependent activation of aPKCzeta/iota mediates the release of Rac from the inhibitory complex with RhoGDI, allowing its activation and leading to formation of membrane ruffles, which constitute essential requirements for cell migration. These findings highlight DGKalpha as the central element of a lipid signaling pathway linking tyrosine kinase growth-factor receptors to regulation of aPKCs and RhoGDI, and providing a positional signal regulating Rac association to the plasma membrane.
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22
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Cai J, Crotty TM, Reichert E, Carraway KL, Stafforini DM, Topham MK. Diacylglycerol kinase delta and protein kinase C(alpha) modulate epidermal growth factor receptor abundance and degradation through ubiquitin-specific protease 8. J Biol Chem 2010; 285:6952-9. [PMID: 20064931 DOI: 10.1074/jbc.m109.055731] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Many human epithelial cancers are characterized by abnormal activation of the epidermal growth factor receptor (EGFR), which is often caused by its excessive expression in tumor cells. The abundance of EGFR is modulated, in part, by its ubiquitination, which targets it for degradation. The components responsible for adding ubiquitin to EGFR are well characterized, but this is a reversible process, and the mechanisms that modulate the removal of ubiquitin from the EGFR are not well known. We found that de-ubiquitination of EGFR was regulated by diacylglycerol kinase delta (DGKdelta), a lipid kinase that terminates diacylglycerol signaling. In DGKdelta-deficient cells, ubiquitination of EGFR was enhanced, which attenuated the steady-state levels of EGFR and promoted its ligand-induced degradation. These effects were not caused by changes in the ubiquitinating apparatus, but instead were due to reduced expression of the de-ubiquitinase, ubiquitin-specific protease 8 (USP8). Depletion of protein kinase Calpha (PKCalpha), a target of diacylglycerol, rescued the levels of USP8 and normalized EGFR degradation in DGKdelta-deficient cells. Moreover, the effects of PKCalpha were caused by its inhibition of Akt, which stabilizes USP8. Our data indicate a novel mechanism where DGKdelta and PKCalpha modulate the levels of ubiquitinated EGFR through Akt and USP8.
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Affiliation(s)
- Jinjin Cai
- Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, Utah 84112, USA
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23
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Phosphatidic acid signaling regulation of Ras superfamily of small guanosine triphosphatases. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:850-5. [PMID: 19540930 DOI: 10.1016/j.bbalip.2009.05.013] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 05/15/2009] [Accepted: 05/18/2009] [Indexed: 11/22/2022]
Abstract
Phosphatidic acid (PA) has been increasingly recognized as an important signaling lipid regulating cell growth and proliferation, membrane trafficking, and cytoskeletal reorganization. Recent studies indicate that the signaling PA generated from phospholipase D (PLD) and diacylglycerol kinase (DGK) plays critical roles in regulating the activity of some members of Ras superfamily of small guanosine triphosphatases (GTPases), such as Ras, Rac and Arf. Change of PA levels regulates the activity of small GTPases by modulating membrane localization and activity of small GTPase regulatory proteins, guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs). In addition, PA also targets some small GTPases to membranes by direct binding. This review summarizes the roles of PLD and DGK in regulating the activity of several Ras superfamily members and cellular processes they control. Some future directions and the implication of PA regulation of Ras small GTPases in pathology are also discussed.
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24
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Morita SY, Ueda K, Kitagawa S. Enzymatic measurement of phosphatidic acid in cultured cells. J Lipid Res 2009; 50:1945-52. [PMID: 19369695 DOI: 10.1194/jlr.d900014-jlr200] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this work, we developed a novel enzymatic method for measuring phosphatidic acid (PA) in cultured cells. The enzymatic reaction sequence of the method involves hydrolysis of PA to produce glycerol-3-phosphate (G3P), which is then oxidized by G3P oxidase to generate hydrogen peroxide. In the presence of peroxidase, hydrogen peroxide reacted with Amplex Red to produce highly fluorescent resorufin. We found that lipase from Pseudomonas sp. can completely hydrolyze PA to G3P and FAs. The calibration curve for PA measurement was linear between 20 and 250 microM, and the detection limit was 5 microM (50 pmol in the reaction mixture). We also modified the method for the enzymatic measurement of lysophosphatidic acid. By this new method, we determined the PA content in the lipid extract from HEK293 cells. The cellular content of PA was decreased with increasing cell density but not correlated with the proliferation rate. The diacylglycerol kinase inhibitor R59949 markedly reduced the cellular PA content, suggesting the diacylglycerol kinase activity was involved in a large part of the PA production in HEK293 cells. This novel method for PA quantification is simple, rapid, specific, sensitive, and high-throughput and will help to study the biological functions of PA and its related enzymes.
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Affiliation(s)
- Shin-ya Morita
- Laboratory of Pharmaceutical Technology, Kobe Pharmaceutical University, Higashinada-ku, Kobe 658-8558, Japan.
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25
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Diacylglycerol kinases as sources of phosphatidic acid. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:942-8. [PMID: 19264149 DOI: 10.1016/j.bbalip.2009.02.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 02/18/2009] [Accepted: 02/18/2009] [Indexed: 11/22/2022]
Abstract
There are ten mammalian diacylglycerol kinases (DGKs) whose primary role is to terminate diacylglycerol (DAG) signaling. However, it is becoming increasingly apparent that DGKs also influence signaling events through their product, phosphatidic acid (PA). They do so in some cases by associating with proteins and then modifying their activity by generating PA. In other cases, DGKs broadly regulate signaling events by virtue of their ability to provide PA for the synthesis of phosphatidylinositols (PtdIns).
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26
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Topham MK, Epand RM. Mammalian diacylglycerol kinases: molecular interactions and biological functions of selected isoforms. Biochim Biophys Acta Gen Subj 2009; 1790:416-24. [PMID: 19364481 DOI: 10.1016/j.bbagen.2009.01.010] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 01/27/2009] [Accepted: 01/30/2009] [Indexed: 12/28/2022]
Abstract
The mammalian diacylglycerol kinases (DGK) are a group of enzymes having important roles in regulating many biological processes. Both the product and the substrate of these enzymes, i.e. diacylglycerol and phosphatidic acid, are important lipid signalling molecules. Each DGK isoform appears to have a distinct biological function as a consequence of its location in the cell and/or the proteins with which it associates. This review discusses three of the more extensively studied forms of this enzyme, DGKalpha, DGKvarepsilon, and DGKzeta. DGKalpha has an important role in immune function and its activity is modulated by several mechanisms. DGKvarepsilon has several unique features among which is its specificity for arachionoyl-containing substrates, suggesting its importance in phosphatidylinositol cycling. DGKzeta is expressed in many tissues and also has several mechanisms to regulate its functions. It is localized in several subcellular organelles, including the nucleus. The current state of our understanding of the properties and functions of these proteins is reviewed.
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Affiliation(s)
- Matthew K Topham
- Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, 2000 Circle of Hope, Salt Lake City, UT 84112, USA
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27
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Stenzinger A, Schreiner D, Koch P, Hofer HW, Wimmer M. Cell and molecular biology of the novel protein tyrosine-phosphatase-interacting protein 51. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 275:183-246. [PMID: 19491056 DOI: 10.1016/s1937-6448(09)75006-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This chapter examines the current state of knowledge about the expression profile, as well as biochemical properties and biological functions of the evolutionarily conserved protein PTPIP51. PTPIP51 is apparently expressed in splice variants and shows a particularly high expression in epithelia, skeletal muscle, placenta, and germ cells, as well as during mammalian development and in cancer. PTPIP51 is an in vitro substrate of Src- and protein kinase A, the PTP1B/TCPTP protein tyrosine phosphatases and interacts with 14-3-3 proteins, the Nuf2 kinetochore protein, the ninein-interacting CGI-99 protein, diacylglycerol kinase alpha, and also with itself forming dimers and trimers. Although the precise cellular function remains to be elucidated, the current data implicate PTPIP51 in signaling cascades mediating proliferation, differentiation, apoptosis, and motility.
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Affiliation(s)
- Albrecht Stenzinger
- Institute of Anatomy and Cell Biology, Justus-Liebig-University, Giessen, Germany
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28
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Milne SB, Ivanova PT, Armstrong MD, Myers DS, Lubarda J, Shulga YV, Topham MK, Brown HA, Epand RM. Dramatic differences in the roles in lipid metabolism of two isoforms of diacylglycerol kinase. Biochemistry 2008; 47:9372-9. [PMID: 18702510 DOI: 10.1021/bi800492c] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Lipid species changes for SV40-transformed fibroblasts from wild-type or from diacylglycerol kinase-epsilon (DGKepsilon) or diacylglycerol kinase-alpha (DGKalpha) knockout mice were determined for glycerophospholipids, polyphosphatidylinositides (GPInsP n ) and diacylglycerol (DAG) using direct infusion mass spectrometry. Dramatic differences in arachidonate (20:4 fatty acid)-containing lipids were observed for multiple classes of glycerophospholipids and polyphosphatidylinositides between wild-type and DGKepsilon knockout cells. However, no difference was observed in either the amount or the acyl chain composition of DAG between DGKepsilon knockout and wild-type cells, suggesting that DGKepsilon catalyzed the phosphorylation of a minor fraction of the DAG in these cells. The differences in arachidonate content between the two cell lines were greatest for the GPInsP n lipids and lowest for DAG. These findings indicate that DGKepsilon plays a significant role in determining the enrichment of GPInsP n with 20:4 and that there is a pathway for the selective translocation of arachidonoyl phosphatidic acid from the plasma membrane to the endoplasmic reticulum. In contrast, no substantial difference was observed in the acyl chain composition of any class of glycerophospholipid or diacylglycerol between lipid extracts from fibroblasts from wild-type mice or from DGKalpha knockout mice. However, the cells from the DGKalpha knockout mice had a higher concentration of DAG, consistent with the lack of downregulation of the major fraction of DAG by DGKalpha, in contrast with DGKepsilon that is primarily responsible for enrichment of GPInsP n with arachidonoyl acyl chains.
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Affiliation(s)
- Stephen B Milne
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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