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Kabeche S, Aida J, Akther T, Ichikawa T, Ochida A, Pulkoski-Gross MJ, Smith M, Humphries PS, Yeh E. Nonbisphosphonate inhibitors of Plasmodium falciparum FPPS/GGPPS. Bioorg Med Chem Lett 2021; 41:127978. [PMID: 33766764 DOI: 10.1016/j.bmcl.2021.127978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/05/2021] [Accepted: 03/14/2021] [Indexed: 11/20/2022]
Abstract
A series of novel thiazole-containing amides were synthesized. A structure-activity relationship study of these compounds led to the identification of potent and selective PfFPPS/GGPPS inhibitors with good in vitro ADME profiles. The most promising candidate molecules were progressed to mouse in vivo PK studies and demonstrated adequate free drug exposure to warrant further investigation.
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Affiliation(s)
- Stephanie Kabeche
- Department of Biochemistry, Stanford Medical School, Stanford University, Stanford, CA 94305, USA
| | - Jumpei Aida
- Research, Takeda Pharmaceutical Company Ltd, 26-1, Muraokahigashi 2-chome Fujisawa, Kanagawa 251-8555, Japan
| | - Thamina Akther
- Research, Takeda Pharmaceutical Company Ltd, 26-1, Muraokahigashi 2-chome Fujisawa, Kanagawa 251-8555, Japan
| | - Takashi Ichikawa
- Research, Takeda Pharmaceutical Company Ltd, 26-1, Muraokahigashi 2-chome Fujisawa, Kanagawa 251-8555, Japan
| | - Atsuko Ochida
- Research, Takeda Pharmaceutical Company Ltd, 26-1, Muraokahigashi 2-chome Fujisawa, Kanagawa 251-8555, Japan
| | - Michael J Pulkoski-Gross
- Department of Biochemistry, Stanford Medical School, Stanford University, Stanford, CA 94305, USA
| | - Mark Smith
- Department of ChEM-H, Stanford University, Stanford, CA 94305, USA
| | - Paul S Humphries
- Department of ChEM-H, Stanford University, Stanford, CA 94305, USA
| | - Ellen Yeh
- Department of Biochemistry, Stanford Medical School, Stanford University, Stanford, CA 94305, USA
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2
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Velazquez FN, Hernandez-Corbacho M, Trayssac M, Stith JL, Bonica J, Jean B, Pulkoski-Gross MJ, Carroll BL, Salama MF, Hannun YA, Snider AJ. Bioactive sphingolipids: Advancements and contributions from the laboratory of Dr. Lina M. Obeid. Cell Signal 2020; 79:109875. [PMID: 33290840 PMCID: PMC8244749 DOI: 10.1016/j.cellsig.2020.109875] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 02/06/2023]
Abstract
Sphingolipids and their synthetic enzymes have emerged as critical mediators in numerous diseases including inflammation, aging, and cancer. One enzyme in particular, sphingosine kinase (SK) and its product sphingosine-1-phosphate (S1P), has been extensively implicated in these processes. SK catalyzes the phosphorylation of sphingosine to S1P and exists as two isoforms, SK1 and SK2. In this review, we will discuss the contributions from the laboratory of Dr. Lina M. Obeid that have defined the roles for several bioactive sphingolipids in signaling and disease with an emphasis on her work defining SK1 in cellular fates and pathobiologies including proliferation, senescence, apoptosis, and inflammation.
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Affiliation(s)
- Fabiola N Velazquez
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA
| | - Maria Hernandez-Corbacho
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA
| | - Magali Trayssac
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA
| | - Jeffrey L Stith
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA
| | - Joseph Bonica
- Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA; Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11790, USA
| | - Bernandie Jean
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA
| | - Michael J Pulkoski-Gross
- Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA; Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11790, USA
| | - Brittany L Carroll
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11790, USA
| | - Mohamed F Salama
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA; Department of Biochemistry, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
| | - Yusuf A Hannun
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA
| | - Ashley J Snider
- Department of Nutritional Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson, AZ 85721, USA.
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3
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Tang Y, Meister TR, Walczak M, Pulkoski-Gross MJ, Hari SB, Sauer RT, Amberg-Johnson K, Yeh E. A mutagenesis screen for essential plastid biogenesis genes in human malaria parasites. PLoS Biol 2019; 17:e3000136. [PMID: 30726238 PMCID: PMC6380595 DOI: 10.1371/journal.pbio.3000136] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/19/2019] [Indexed: 02/06/2023] Open
Abstract
Endosymbiosis has driven major molecular and cellular innovations. Plasmodium spp. parasites that cause malaria contain an essential, non-photosynthetic plastid-the apicoplast-which originated from a secondary (eukaryote-eukaryote) endosymbiosis. To discover organellar pathways with evolutionary and biomedical significance, we performed a mutagenesis screen for essential genes required for apicoplast biogenesis in Plasmodium falciparum. Apicoplast(-) mutants were isolated using a chemical rescue that permits conditional disruption of the apicoplast and a new fluorescent reporter for organelle loss. Five candidate genes were validated (out of 12 identified), including a triosephosphate isomerase (TIM)-barrel protein that likely derived from a core metabolic enzyme but evolved a new activity. Our results demonstrate, to our knowledge, the first forward genetic screen to assign essential cellular functions to unannotated P. falciparum genes. A putative TIM-barrel enzyme and other newly identified apicoplast biogenesis proteins open opportunities to discover new mechanisms of organelle biogenesis, molecular evolution underlying eukaryotic diversity, and drug targets against multiple parasitic diseases.
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Affiliation(s)
- Yong Tang
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
| | - Thomas R. Meister
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Marta Walczak
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
| | - Michael J. Pulkoski-Gross
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
| | - Sanjay B. Hari
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Robert T. Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Katherine Amberg-Johnson
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Ellen Yeh
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Pathology, Stanford University School of Medicine, Stanford, California, United States of America
- Chan Zuckerberg Biohub, San Francisco, California, United States of America
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4
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Pulkoski-Gross MJ, Obeid LM. Molecular mechanisms of regulation of sphingosine kinase 1. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:1413-1422. [PMID: 30591148 DOI: 10.1016/j.bbalip.2018.08.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 08/27/2018] [Accepted: 08/28/2018] [Indexed: 01/08/2023]
Abstract
Within the last 3 decades, there has been intense study of bioactive sphingolipids and the enzymes which metabolize those lipids. One enzyme is the critical lipid kinase sphingosine kinase 1 (SK1), which produces the potent and pleiotropic signaling lipid, sphingosine 1-phosphate (S1P). SK1 and S1P have been implicated in a host of different diseases including cancer, chronic inflammation, and metabolic diseases. However, while there is ample knowledge about the importance of these molecules in the development and progression of disease there is a dearth of knowledge of the molecular mechanisms which regulate SK1 function. In this review, we will cover some of the more recent and exciting findings about the different ways SK1 function can be regulated, from transcriptional regulation to protein stability. Finally, we will delve into recent structural insights into SK1 and how they might relate to function at cell membranes.
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Affiliation(s)
- Michael J Pulkoski-Gross
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11790, USA; Department of Medicine, The Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11790, USA.
| | - Lina M Obeid
- Department of Medicine, The Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11790, USA; Northport Veterans Affairs Medical Center, Northport, NY 11768, USA.
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5
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Pulkoski-Gross MJ, Jenkins ML, Truman JP, Salama MF, Clarke CJ, Burke JE, Hannun YA, Obeid LM. An intrinsic lipid-binding interface controls sphingosine kinase 1 function. J Lipid Res 2018; 59:462-474. [PMID: 29326159 DOI: 10.1194/jlr.m081307] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/04/2018] [Indexed: 12/15/2022] Open
Abstract
Sphingosine kinase 1 (SK1) is required for production of sphingosine-1-phosphate (S1P) and thereby regulates many cellular processes, including cellular growth, immune cell trafficking, and inflammation. To produce S1P, SK1 must access sphingosine directly from membranes. However, the molecular mechanisms underlying SK1's direct membrane interactions remain unclear. We used hydrogen/deuterium exchange MS to study interactions of SK1 with membrane vesicles. Using the CRISPR/Cas9 technique to generate HCT116 cells lacking SK1, we explored the effects of membrane interface disruption and the function of the SK1 interaction site. Disrupting the interface resulted in reduced membrane association and decreased cellular SK1 activity. Moreover, SK1-dependent signaling, including cell invasion and endocytosis, was abolished upon mutation of the membrane-binding interface. Of note, we identified a positively charged motif on SK1 that is responsible for electrostatic interactions with membranes. Furthermore, we demonstrated that SK1 uses a single contiguous interface, consisting of an electrostatic site and a hydrophobic site, to interact with membrane-associated anionic phospholipids. Altogether, these results define a composite domain in SK1 that regulates its intrinsic ability to bind membranes and indicate that this binding is critical for proper SK1 function. This work will allow for a new line of thinking for targeting SK1 in disease.
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Affiliation(s)
- Michael J Pulkoski-Gross
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11790.,Department of Medicine and Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11790
| | - Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8N 1A1, Canada
| | - Jean-Philip Truman
- Department of Medicine and Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11790
| | - Mohamed F Salama
- Department of Biochemistry, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35511, Egypt
| | - Christopher J Clarke
- Department of Medicine and Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11790
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8N 1A1, Canada
| | - Yusuf A Hannun
- Department of Medicine and Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11790
| | - Lina M Obeid
- Department of Medicine and Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11790 .,Northport Veterans Affairs Medical Center, Northport, NY 11768
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6
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Pulkoski-Gross MJ, Uys JD, Orr-Gandy KA, Coant N, Bialkowska AB, Szulc ZM, Bai A, Bielawska A, Townsend DM, Hannun YA, Obeid LM, Snider AJ. Novel sphingosine kinase-1 inhibitor, LCL351, reduces immune responses in murine DSS-induced colitis. Prostaglandins Other Lipid Mediat 2017; 130:47-56. [PMID: 28377281 PMCID: PMC5509055 DOI: 10.1016/j.prostaglandins.2017.03.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/25/2017] [Accepted: 03/28/2017] [Indexed: 02/07/2023]
Abstract
Sphingosine-1-phosphate (S1P) is a biologically active sphingolipid metabolite which has been implicated in many diseases including cancer and inflammatory diseases. Recently, sphingosine kinase 1 (SK1), one of the isozymes which generates S1P, has been implicated in the development and progression of inflammatory bowel disease (IBD). Based on our previous work, we set out to determine the efficacy of a novel SK1 selective inhibitor, LCL351, in a murine model of IBD. LCL351 selectively inhibits SK1 both in vitro and in cells. LCL351, which accumulates in relevant tissues such as colon, did not have any adverse side effects in vivo. In mice challenged with dextran sodium sulfate (DSS), a murine model for IBD, LCL351 treatment protected from blood loss and splenomegaly. Additionally, LCL351 treatment reduced the expression of pro-inflammatory markers, and reduced neutrophil infiltration in colon tissue. Our results suggest inflammation associated with IBD can be targeted pharmacologically through the inhibition and degradation of SK1. Furthermore, our data also identifies desirable properties of SK1 inhibitors.
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Affiliation(s)
- Michael J Pulkoski-Gross
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, USA; Department of Medicine and the, Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, USA
| | - Joachim D Uys
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, USA
| | - K Alexa Orr-Gandy
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Nicolas Coant
- Department of Medicine and the, Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, USA
| | - Agnieszka B Bialkowska
- Department of Medicine and the, Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, USA
| | - Zdzislaw M Szulc
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Aiping Bai
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Alicja Bielawska
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Danyelle M Townsend
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Yusuf A Hannun
- Department of Medicine and the, Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, USA
| | - Lina M Obeid
- Department of Medicine and the, Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, USA; Northport Veterans Affairs Medical Center, Northport, NY, USA
| | - Ashley J Snider
- Department of Medicine and the, Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, USA; Northport Veterans Affairs Medical Center, Northport, NY, USA.
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7
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Carroll BL, Pulkoski-Gross MJ, Hannun YA, Obeid LM. CHK1 regulates NF-κB signaling upon DNA damage in p53- deficient cells and associated tumor-derived microvesicles. Oncotarget 2017; 7:18159-70. [PMID: 26921248 PMCID: PMC4951279 DOI: 10.18632/oncotarget.7566] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 01/23/2016] [Indexed: 12/15/2022] Open
Abstract
The recently discovered CHK1-Suppressed (CS) pathway is activated by inhibition or loss of the checkpoint kinase CHK1, promoting an apoptotic response to DNA damage mediated by caspase-2 in p53-deficient cells. Although functions of the CS-pathway have been investigated biochemically, it remains unclear whether and how CHK1 inhibition can be regulated endogenously and whether this constitutes a key component of the DNA damage response (DDR). Here, we present data that define the first endogenous activation of the CS-pathway whereby, upon DNA damage, wild type p53 acts as an endogenous regulator of CHK1 levels that modulates caspase-2 activation. Moreover, we demonstrate that persistence of CHK1 levels in response to DNA damage in p53-deficient cancer cells, leads to CHK1-mediated activation of NF-κB and induction of NF-κB-regulated genes in cells and in associated tumor-derived microvesicles (TMVs), both of which are abrogated by loss or inhibition of CHK1. These data define a novel role for CHK1 in the DDR pathway as a regulator NF-κB activity. Our data provide evidence that targeting CHK1 in p53-deficient cancers may abrogate NF-κB signaling that is associated with increased cellular survival and chemoresistance.
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Affiliation(s)
- Brittany L Carroll
- Stony Brook Cancer Center and The Department of Medicine, Stony Brook, New York, USA
| | - Michael J Pulkoski-Gross
- Stony Brook Cancer Center and The Department of Medicine, Stony Brook, New York, USA.,Pharmacological Sciences, Stony Brook University, Health Sciences Center, Stony Brook, New York, USA
| | - Yusuf A Hannun
- Stony Brook Cancer Center and The Department of Medicine, Stony Brook, New York, USA
| | - Lina M Obeid
- Stony Brook Cancer Center and The Department of Medicine, Stony Brook, New York, USA.,Northport Veterans Affairs Medical Center, Northport, New York, USA
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8
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Airola MV, Allen WJ, Pulkoski-Gross MJ, Obeid LM, Rizzo RC, Hannun YA. Structural Basis for Ceramide Recognition and Hydrolysis by Human Neutral Ceramidase. Structure 2015; 23:1482-1491. [PMID: 26190575 PMCID: PMC4830088 DOI: 10.1016/j.str.2015.06.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 06/03/2015] [Accepted: 06/11/2015] [Indexed: 01/07/2023]
Abstract
Neutral ceramidase (nCDase) catalyzes conversion of the apoptosis-associated lipid ceramide to sphingosine, the precursor for the proliferative factor sphingosine-1-phosphate. As an enzyme regulating the balance of ceramide and sphingosine-1-phosphate, nCDase is emerging as a therapeutic target for cancer. Here, we present the 2.6-Å crystal structure of human nCDase in complex with phosphate that reveals a striking, 20-Å deep, hydrophobic active site pocket stabilized by a eukaryotic-specific subdomain not present in bacterial ceramidases. Utilizing flexible ligand docking, we predict a likely binding mode for ceramide that superimposes closely with the crystallographically observed transition state analog phosphate. Our results suggest that nCDase uses a new catalytic strategy for Zn(2+)-dependent amidases, and generates ceramide specificity by sterically excluding sphingolipids with bulky headgroups and specifically recognizing the small hydroxyl head group of ceramide. Together, these data provide a foundation to aid drug development and establish common themes for how proteins recognize the bioactive lipid ceramide.
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Affiliation(s)
- Michael V Airola
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Department of Medicine, Stony Brook Cancer Center, Stony Brook, NY 11794, USA
| | - William J Allen
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY 11794, USA
| | | | - Lina M Obeid
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Department of Medicine, Stony Brook Cancer Center, Stony Brook, NY 11794, USA; Department of Medicine, Northport Veterans Affairs Medical Center, Northport, NY 11768, USA
| | - Robert C Rizzo
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY 11794, USA
| | - Yusuf A Hannun
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Department of Medicine, Stony Brook Cancer Center, Stony Brook, NY 11794, USA.
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9
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Adada MM, Canals D, Jeong N, Kelkar AD, Hernandez-Corbacho M, Pulkoski-Gross MJ, Donaldson JC, Hannun YA, Obeid LM. Intracellular sphingosine kinase 2-derived sphingosine-1-phosphate mediates epidermal growth factor-induced ezrin-radixin-moesin phosphorylation and cancer cell invasion. FASEB J 2015. [PMID: 26209696 DOI: 10.1096/fj.15-274340] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The bioactive sphingolipid sphingosine-1-phosphate (S1P) mediates cellular proliferation, mitogenesis, inflammation, and angiogenesis. These biologies are mediated through S1P binding to specific GPCRs [sphingosine-1-phosphate receptor (S1PR)1-5] and some other less well-characterized intracellular targets. Ezrin-radixin-moesin (ERM) proteins, a family of adaptor molecules linking the cortical actin cytoskeleton to the plasma membrane, are emerging as critical regulators of cancer invasion via regulation of cell morphology and motility. Recently, we identified S1P as an acute ERM activator (via phosphorylation) through its action on S1PR2. In this work, we dissect the mechanism of S1P generation downstream of epidermal growth factor (EGF) leading to ERM phosphorylation and cancer invasion. Using pharmacologic inhibitors, small interfering RNA technologies, and genetic approaches, we demonstrate that sphingosine kinase (SK)2, and not SK1, is essential and sufficient in EGF-mediated ERM phosphorylation in HeLa cells. In fact, knocking down SK2 decreased ERM activation 2.5-fold. Furthermore, we provide evidence that SK2 is necessary to mediate EGF-induced invasion. In addition, overexpressing SK2 causes a 2-fold increase in HeLa cell invasion. Surprisingly, and for the first time, we find that this event, although dependent on S1PR2 activation, does not generate and does not require extracellular S1P secretion, therefore introducing a potential novel model of autocrine/intracrine action of S1P that still involves its GPCRs. These results define new mechanistic insights for EGF-mediated invasion and novel actions of SK2, therefore setting the stage for novel targets in the treatment of growth factor-driven malignancies.
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Affiliation(s)
- Mohamad M Adada
- *Department of Medicine and the Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, USA; and Northport Veterans Affairs Medical Center, North Port, New York, USA
| | - Daniel Canals
- *Department of Medicine and the Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, USA; and Northport Veterans Affairs Medical Center, North Port, New York, USA
| | - Nara Jeong
- *Department of Medicine and the Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, USA; and Northport Veterans Affairs Medical Center, North Port, New York, USA
| | - Ashwin D Kelkar
- *Department of Medicine and the Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, USA; and Northport Veterans Affairs Medical Center, North Port, New York, USA
| | - Maria Hernandez-Corbacho
- *Department of Medicine and the Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, USA; and Northport Veterans Affairs Medical Center, North Port, New York, USA
| | - Michael J Pulkoski-Gross
- *Department of Medicine and the Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, USA; and Northport Veterans Affairs Medical Center, North Port, New York, USA
| | - Jane C Donaldson
- *Department of Medicine and the Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, USA; and Northport Veterans Affairs Medical Center, North Port, New York, USA
| | - Yusuf A Hannun
- *Department of Medicine and the Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, USA; and Northport Veterans Affairs Medical Center, North Port, New York, USA
| | - Lina M Obeid
- *Department of Medicine and the Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, USA; and Northport Veterans Affairs Medical Center, North Port, New York, USA
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10
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Abstract
Sphingolipids represent an important class of bioactive signaling lipids which have key roles in numerous cellular processes. Over the last few decades, the levels of bioactive sphingolipids and/or their metabolizing enzymes have been realized to be important factors involved in disease development and progression, most notably in cancer. Targeting sphingolipid-metabolizing enzymes in disease states has been the focus of many studies and has resulted in a number of pharmacological inhibitors, with some making it into the clinic as therapeutics. In order to better understand the regulation of sphingolipid-metabolizing enzymes as well as to develop much more potent and specific inhibitors, the field of sphingolipids has recently taken a turn toward structural biology. The last decade has seen the structural determination of a number of sphingolipid enzymes and effector proteins. In these terms, one of the most complete arms of the sphingolipid pathway is the sphingosine-1-phosphate (S1P) arm. The structures of proteins involved in the function and regulation of S1P are being used to investigate further the regulation of said proteins as well as in the design and development of inhibitors as potential therapeutics.
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Affiliation(s)
| | - Jane C Donaldson
- b Department of Medicine , Stony Brook University , Stony Brook , NY , USA .,c Stony Brook Cancer Center , Stony Brook , NY , USA , and
| | - Lina M Obeid
- b Department of Medicine , Stony Brook University , Stony Brook , NY , USA .,c Stony Brook Cancer Center , Stony Brook , NY , USA , and.,d Northport Veterans Affairs Medical Center , Northport , NY , USA
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