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Lee C, Chen Y, Hernandez E, Pong R, Ma S, Hofstad M, Kapur P, Zhau H, Chung LWK, Lai C, Lin H, Lee M, Raj GV, Hsieh J. The central role of Sphingosine kinase 1 in the development of neuroendocrine prostate cancer (NEPC): A new targeted therapy of NEPC. Clin Transl Med 2022; 12:e695. [PMID: 35184376 PMCID: PMC8858611 DOI: 10.1002/ctm2.695] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/09/2021] [Accepted: 12/20/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Neuroendocrine prostate cancer (NEPC) is often diagnosed as a sub-type from the castration-resistant prostate cancer (CRPC) recurred from the second generation of anti-androgen treatment and is a rapidly progressive fatal disease. The molecular mechanisms underlying the trans-differentiation from CRPC to NEPC are not fully characterized, which hampers the development of effective targeted therapy. METHODS Bioinformatic analyses were conducted to determine the clinical correlation of sphingosine kinase 1 (SphK1) in CRPC progression. To investigate the transcriptional regulation SphK1 and neuroendocrine (NE) transcription factor genes, both chromosome immunoprecipitation and luciferase reporter gene assays were performed. To demonstrate the role of SphK1 in NEPC development, neurosphere assay was carried out along with several biomarkers determined by quantitative PCR and western blot. Furthermore, in vivo NEPC xenograft models and patient-derived xenograft (PDX) model were employed to determine the effect of SphK1 inhibitors and target validation. RESULTS Significant prevalence of SphK1 in NEPC development is observed from clinical datasets. SphK1 is transcriptionally repressed by androgen receptor-RE1-silencing transcription factor (REST) complex. Furthermore, sphingosine 1-phosphate produced by SphK1 can modulate REST protein turnover via MAPK signaling pathway. Also, decreased REST protein levels enhance the expression of NE markers in CRPC, enabling the transition to NEPC. Finally, specific SphK1 inhibitors can effectively inhibit the growth of NEPC tumors and block the REST protein degradation in PDX. CONCLUSIONS SphK1 plays a central role in NEPC development, which offers a new target for this lethal cancer using clinically approved SphK1 inhibitors.
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Affiliation(s)
- Cheng‐Fan Lee
- Department of UrologyUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Department of Biochemistry and Molecular BiologyCollege of MedicineNational Taiwan UniversityTaipeiTaiwan
| | - Yu‐An Chen
- Department of UrologyUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Elizabeth Hernandez
- Department of UrologyUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Rey‐Chen Pong
- Department of UrologyUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Shihong Ma
- Department of UrologyUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Mia Hofstad
- Department of UrologyUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Payal Kapur
- Urology and PathologyUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Haiyen Zhau
- Uro‐Oncology ResearchDepartment of MedicineCedars‐Sinai Medical CenterLos AngelesCaliforniaUSA
| | - Leland WK Chung
- Uro‐Oncology ResearchDepartment of MedicineCedars‐Sinai Medical CenterLos AngelesCaliforniaUSA
| | - Chih‐Ho Lai
- Department of Microbiology and ImmunologyGraduate Institute of Biomedical SciencesCollege of MedicineChang Gung UniversityTaoyuanTaiwan
| | - Ho Lin
- Department of Life SciencesNational Chung Hsing UniversityTaichungTaiwan
| | - Ming‐Shyue Lee
- Department of Biochemistry and Molecular BiologyCollege of MedicineNational Taiwan UniversityTaipeiTaiwan
| | - Ganesh V Raj
- Department of UrologyUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Department of PharmacologyUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Jer‐Tsong Hsieh
- Department of UrologyUniversity of Texas Southwestern Medical CenterDallasTexasUSA
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Brown RDR, Veerman BEP, Oh J, Tate RJ, Torta F, Cunningham MR, Adams DR, Pyne S, Pyne NJ. A new model for regulation of sphingosine kinase 1 translocation to the plasma membrane in breast cancer cells. J Biol Chem 2021; 296:100674. [PMID: 33865856 PMCID: PMC8135045 DOI: 10.1016/j.jbc.2021.100674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/01/2021] [Accepted: 04/14/2021] [Indexed: 01/24/2023] Open
Abstract
The translocation of sphingosine kinase 1 (SK1) to the plasma membrane (PM) is crucial in promoting oncogenesis. We have previously proposed that SK1 exists as both a monomer and dimer in equilibrium, although it is unclear whether these species translocate to the PM via the same or different mechanisms. We therefore investigated the structural determinants involved to better understand how translocation might potentially be targeted for therapeutic intervention. We report here that monomeric WT mouse SK1 (GFP-mSK1) translocates to the PM of MCF-7L cells stimulated with carbachol or phorbol 12-myristate 13-acetate, whereas the dimer translocates to the PM in response to sphingosine-1-phosphate; thus, the equilibrium between the monomer and dimer is sensitive to cellular stimulus. In addition, carbachol and phorbol 12-myristate 13-acetate induced translocation of monomeric GFP-mSK1 to lamellipodia, whereas sphingosine-1-phosphate induced translocation of dimeric GFP-mSK1 to filopodia, suggesting that SK1 regulates different cell biological processes dependent on dimerization. GFP-mSK1 mutants designed to modulate dimerization confirmed this difference in localization. Regulation by the C-terminal tail of SK1 was investigated using GFP-mSK1 truncations. Removal of the last five amino acids (PPEEP) prevented translocation of the enzyme to the PM, whereas removal of the last ten amino acids restored translocation. This suggests that the penultimate five amino acids (SRRGP) function as a translocation brake, which can be released by sequestration of the PPEEP sequence. We propose that these determinants alter the arrangement of N-terminal and C-terminal domains in SK1, leading to unique surfaces that promote differential translocation to the PM.
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Affiliation(s)
- Ryan D R Brown
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, Scotland, UK
| | - Ben E P Veerman
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, Scotland, UK
| | - Jeongah Oh
- SLING, Singapore Lipidomics Incubator, Life Sciences Institute and Department of Biochemistry, YLL School of Medicine, National University of Singapore, Singapore, Singapore
| | - Rothwelle J Tate
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, Scotland, UK
| | - Federico Torta
- SLING, Singapore Lipidomics Incubator, Life Sciences Institute and Department of Biochemistry, YLL School of Medicine, National University of Singapore, Singapore, Singapore
| | - Margaret R Cunningham
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, Scotland, UK
| | - David R Adams
- School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh, UK
| | - Susan Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, Scotland, UK
| | - Nigel J Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, Scotland, UK.
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Hengst JA, Hegde S, Paulson RF, Yun JK. Development of SKI-349, a dual-targeted inhibitor of sphingosine kinase and microtubule polymerization. Bioorg Med Chem Lett 2020; 30:127453. [PMID: 32736077 DOI: 10.1016/j.bmcl.2020.127453] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/22/2020] [Accepted: 07/24/2020] [Indexed: 11/28/2022]
Abstract
Our sphingosine kinase inhibitor (SKI) optimization studies originated with the optimization of the SKI-I chemotype by replacement of the substituted benzyl rings with substituted phenyl rings giving rise to the discovery of SKI-178. We have recently reported that SKI-178 is a dual-targeted inhibitor of both sphingosine kinase isoforms (SphK1/2) and a microtubule disrupting agent (MDA). In mechanism-of-action studies, we have shown that these two separate actions synergize to induce cancer cell death in acute myeloid leukemia (AML) cell and animal models. Owning to the effectiveness of SKI-178, we sought to further refine the chemotype while maintaining "on-target" SKI and MDA activities. Herein, we modified the "linker region" between the substituted phenyl rings of SKI-178 through a structure guided approach. These studies have yielded the discovery of an SKI-178 congener, SKI-349, with log-fold enhancements in both SphK inhibition and cytotoxic potency. Importantly, SKI-349 also demonstrates log-fold improvements in therapeutic efficacy in a retro-viral transduction model of MLL-AF9 AML as compared to previous studies with SKI-178. Together, our results strengthen the hypothesis that simultaneous targeting of the sphingosine kinases (SphK1/2) and the induction of mitotic spindle assembly checkpoint arrest, via microtubule disruption, might be an effective therapeutic strategy for hematological malignancies including AML.
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Affiliation(s)
- Jeremy A Hengst
- Department of Pharmacology, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA, USA
| | - Shailaja Hegde
- Hoxworth Blood Center, University of Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Robert F Paulson
- Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA, USA
| | - Jong K Yun
- Department of Pharmacology, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA, USA.
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Abstract
There is substantial evidence that the enzymes, sphingosine kinase 1 and 2, which catalyse the formation of the bioactive lipid sphingosine 1-phosphate, are involved in pathophysiological processes. In this chapter, we appraise the evidence that both enzymes are druggable and describe how isoform-specific inhibitors can be developed based on the plasticity of the sphingosine-binding site. This is contextualised with the effect of sphingosine kinase inhibitors in cancer, pulmonary hypertension, neurodegeneration, inflammation and sickling.
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Affiliation(s)
- Susan Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde , Glasgow, Scotland, UK
| | - David R Adams
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, Scotland, UK
| | - Nigel J Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde , Glasgow, Scotland, UK.
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Adams DR, Tawati S, Berretta G, Rivas PL, Baiget J, Jiang Z, Alsfouk A, Mackay SP, Pyne NJ, Pyne S. Topographical Mapping of Isoform-Selectivity Determinants for J-Channel-Binding Inhibitors of Sphingosine Kinases 1 and 2. J Med Chem 2019; 62:3658-3676. [DOI: 10.1021/acs.jmedchem.9b00162] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- David R. Adams
- School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Salha Tawati
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, U.K
| | - Giacomo Berretta
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, U.K
| | - Paula Lopez Rivas
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, U.K
| | - Jessica Baiget
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, U.K
| | - Zhong Jiang
- School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Aisha Alsfouk
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, U.K
| | - Simon P. Mackay
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, U.K
| | - Nigel J. Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, U.K
| | - Susan Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, U.K
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Nishino S, Yamashita H, Tamori M, Mashimo M, Yamagata K, Nakamura H, Murayama T. Translocation and activation of sphingosine kinase 1 by ceramide‐1‐phosphate. J Cell Biochem 2018; 120:5396-5408. [DOI: 10.1002/jcb.27818] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 09/12/2018] [Indexed: 12/29/2022]
Affiliation(s)
- Shohei Nishino
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University Chiba Japan
| | - Hisahiro Yamashita
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University Chiba Japan
| | - Mizuki Tamori
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University Chiba Japan
| | - Masato Mashimo
- Laboratory of Pharmacology, Faculty of Pharmaceutical Sciences, Doshisha Women’s College of Liberal Arts Kyoto Japan
| | - Kazuyuki Yamagata
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University Chiba Japan
- Laboratory of International Scholars in Pharmaceuticals in Systems Biology, Graduate School of Pharmaceutical Sciences, Chiba University Chiba Japan
| | - Hiroyuki Nakamura
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University Chiba Japan
| | - Toshihiko Murayama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University Chiba Japan
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7
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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] [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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8
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Pyne NJ, El Buri A, Adams DR, Pyne S. Sphingosine 1-phosphate and cancer. Adv Biol Regul 2017; 68:97-106. [PMID: 28942351 DOI: 10.1016/j.jbior.2017.09.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 09/13/2017] [Accepted: 09/13/2017] [Indexed: 01/08/2023]
Abstract
The bioactive lipid, sphingosine 1-phosphate (S1P) is produced by phosphorylation of sphingosine and this is catalysed by two sphingosine kinase isoforms (SK1 and SK2). Here we discuss structural functional aspects of SK1 (which is a dimeric quaternary enzyme) that relate to coordinated coupling of membrane association with phosphorylation of Ser225 in the 'so-called' R-loop, catalytic activity and protein-protein interactions (e.g. TRAF2, PP2A and Gq). S1P formed by SK1 at the plasma-membrane is released from cells via S1P transporters to act on S1P receptors to promote tumorigenesis. We discuss here an additional novel mechanism that can operate between cancer cells and fibroblasts and which involves the release of the S1P receptor, S1P2 in exosomes from breast cancer cells that regulates ERK-1/2 signalling in fibroblasts. This novel mechanism of signalling might provide an explanation for the role of S1P2 in promoting metastasis of cancer cells and which is dependent on the micro-environmental niche.
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Affiliation(s)
- Nigel J Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral St, Glasgow, G4 0RE, Scotland, UK.
| | - Ashref El Buri
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral St, Glasgow, G4 0RE, Scotland, UK
| | - David R Adams
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, Scotland, UK
| | - Susan Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral St, Glasgow, G4 0RE, Scotland, UK
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9
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Sphingosine Kinases: Emerging Structure-Function Insights. Trends Biochem Sci 2016; 41:395-409. [PMID: 27021309 DOI: 10.1016/j.tibs.2016.02.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/08/2016] [Accepted: 02/17/2016] [Indexed: 12/15/2022]
Abstract
Sphingosine kinases (SK1 and SK2) catalyse the conversion of sphingosine into sphingosine 1-phosphate and control fundamental cellular processes, including cell survival, proliferation, differentiation, migration, and immune function. In this review, we highlight recent breakthroughs in the structural and functional characterisation of SK1 and these are contextualised by analysis of crystal structures for closely related prokaryotic lipid kinases. We identify a putative dimerisation interface and propose novel regulatory mechanisms governing structural plasticity induced by phosphorylation and interaction with phospholipids and proteins. Our analysis suggests that the catalytic function and regulation of the enzymes might be dependent on conformational mobility and it provides a roadmap for future interrogation of SK1 function and its role in physiology and disease.
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Mizutani N, Kobayashi M, Sobue S, Ichihara M, Ito H, Tanaka K, Iwaki S, Fujii S, Ito Y, Tamiya-Koizumi K, Takagi A, Kojima T, Naoe T, Suzuki M, Nakamura M, Banno Y, Nozawa Y, Murate T. Sphingosine kinase 1 expression is downregulated during differentiation of Friend cells due to decreased c-MYB. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1006-16. [DOI: 10.1016/j.bbamcr.2013.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Revised: 12/23/2012] [Accepted: 01/02/2013] [Indexed: 12/19/2022]
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Localized sphingolipid signaling at presynaptic terminals is regulated by calcium influx and promotes recruitment of priming factors. J Neurosci 2013; 32:17909-20. [PMID: 23223309 DOI: 10.1523/jneurosci.2808-12.2012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Activity-dependent changes in presynaptic function represent a critical mechanism by which synaptic strength is controlled. However, how changes in synaptic activity couple to presynaptic components to control synaptic vesicle release and recycling are poorly understood. Sphingosine kinase (SphK) is a sphingolipid metabolic enzyme whose activity-dependent recruitment to membrane regions within presynaptic terminals promotes neurotransmitter release. Here, we show that synaptic recruitment of SPHK-1, the SphK ortholog in Caenorhabditis elegans, is mediated by presynaptic calcium influx. Quantitative fluorescence imaging of live presynaptic terminals reveals that blocking presynaptic calcium influx reduces synaptic SPHK-1 abundance whereas increasing calcium influx increases SPHK-1 synaptic abundance. CALM-1, the calcium and integrin binding protein ortholog, colocalizes with SPHK-1 at release sites and regulates muscarinic-mediated synaptic SPHK-1 recruitment. We identify two additional sphingolipid metabolic enzymes that are concentrated at presynaptic terminals, and mutants lacking one of these, HYL-1/ceramide synthase, have defects in synaptic transmission and in synaptic vesicle cycling. Finally, we show that SPHK-1 activity is required for the recruitment of the priming protein UNC-13/Munc13 to presynaptic terminals following activation by muscarinic signaling. These findings suggest that calcium-dependent regulation of local S1P metabolism at synapses may be an important mechanism by which synaptic vesicle priming factors are recruited to release sites to promote synaptic transmission.
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Baker DL, Pham TCT, Sparks MA. Structure and catalytic function of sphingosine kinases: analysis by site-directed mutagenesis and enzyme kinetics. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:139-46. [PMID: 23000541 DOI: 10.1016/j.bbalip.2012.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 09/12/2012] [Accepted: 09/13/2012] [Indexed: 12/17/2022]
Abstract
Sphingosine kinases 1 and 2 (SK1 and SK2) generate the bioactive lipid mediator sphingosine 1-phosphate and as such play a significant role in cell fate and in human health and disease. Despite significant interest in and examination of the role played by SK enzymes in disease, comparatively little is currently known about the three-dimensional structure and catalytic mechanisms of these enzymes. To date, limited numbers of studies have used site directed mutagenesis and activity determinations to examine the roles of individual SK residues in substrate, calmodulin, and membrane binding, as well as activation via phosphorylation. Assays are currently available that allow for both single and bisubstrate kinetic analysis of mutant proteins that show normal, lowered and enhanced activity as compared to wild type controls. Additional studies will be required to build on this foundation to completely understand SK mediated substrate binding and phosphoryl group transfer. A deeper understanding of the SK catalytic mechanism, as well as SK interactions with potential small molecule inhibitors will be invaluable to the future design and identification of SK activity modulators as research tools and potential therapeutics. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.
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Affiliation(s)
- Daniel L Baker
- Department of Chemistry, University of Memphis, Memphis, TN 38152, USA.
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Madhunapantula SV, Hengst J, Gowda R, Fox TE, Yun JK, Robertson GP. Targeting sphingosine kinase-1 to inhibit melanoma. Pigment Cell Melanoma Res 2012; 25:259-74. [PMID: 22236408 DOI: 10.1111/j.1755-148x.2012.00970.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Resistance to therapies develops rapidly for melanoma leading to more aggressive disease. Therefore, agents are needed that specifically inhibit proteins or pathways controlling the development of this disease, which can be combined, dependent on genes deregulated in a particular patient's tumors. This study shows that elevated sphingosine-1-phosphate (S-1-P) levels resulting from increased activity of sphingosine kinase-1 (SPHK1) occur in advanced melanomas. Targeting SPHK1 using siRNA decreased anchorage-dependent and -independent growth as well as sensitized melanoma cells to apoptosis-inducing agents. Pharmacological SPHK1 inhibitors SKI-I but not SKI-II decreased S-1-P content, elevated ceramide levels, caused a G2-M block and induced apoptotic cell death in melanomas. Targeting SPHK1 using siRNA or the pharmacological agent called SKI-I decreased the levels of pAKT. Furthermore, SKI-I inhibited the expression of CYCLIN D1 protein and increased the activity of caspase-3/7, which in turn led to the degradation of PARP. In animals, SKI-I but not SKI-II retarded melanoma growth by 25-40%. Thus, targeting SPHK1 using siRNAs or SKI-I has therapeutic potential for melanoma treatment either alone or in combination with other targeted agents.
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Ali-Rahmani F, Hengst JA, Connor JR, Schengrund CL. Effect of HFE variants on sphingolipid expression by SH-SY5Y human neuroblastoma cells. Neurochem Res 2011; 36:1687-96. [PMID: 21243428 DOI: 10.1007/s11064-011-0403-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2011] [Indexed: 02/08/2023]
Abstract
C282Y and H63D are two common variants of the hemochromatosis protein HFE. SH-SY5Y human neuroblastoma cells stably transfected to express either wild type HFE (WT-HFE), or the C282Y or H63D allele were analyzed for effect of expression of the mutant proteins on transcription of 14 enzymes involved in sphingolipid metabolism. Cells expressing the C282Y variant showed significant increases (>2-fold) in transcription of five genes and decreases in two compared to that seen for cells expressing WT-HFE, while cells expressing the H63D variant showed an elevation in transcription of one gene and a decrease in two. These changes were seen as alterations in ganglioside composition, cell surface binding by the binding subunit of cholera toxin, expression of sphingosine-kinase-1 and synthesis of sphingosine-1-phosphate. These changes may explain why C282Y-HFE is a risk factor for colon and breast cancer and possibly protective against Alzheimer's disease while H63D-HFE is a risk factor for neurodegenerative diseases.
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Affiliation(s)
- F Ali-Rahmani
- Department of Biochemistry and Molecular Biology H171, The Pennsylvania State University College of Medicine, 500 University Dr., Hershey, PA 17033, USA
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Hengst JA, Wang X, Sk UH, Sharma AK, Amin S, Yun JK. Development of a sphingosine kinase 1 specific small-molecule inhibitor. Bioorg Med Chem Lett 2010; 20:7498-502. [PMID: 21050755 DOI: 10.1016/j.bmcl.2010.10.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 09/29/2010] [Accepted: 10/01/2010] [Indexed: 12/11/2022]
Abstract
The sphingolipid metabolic pathway represents a potential source of new therapeutic targets for numerous hyperproliferative/inflammatory diseases. Targets such as the sphingosine kinases (SphKs) have been extensively studied and numerous strategies have been employed to develop inhibitors against these enzymes. Herein, we report on the optimization of our novel small-molecule inhibitor SKI-I (N'-[(2-hydroxy-1-naphthyl)methylene]-3-(2-naphthyl)-1H-pyrazole-5-carbohydrazide) and the identification of a SphK1-specific analog, SKI-178, that is active in vitro and in vivo. This SphK1 specific small-molecule, non-lipid like, inhibitor will be of use to elucidate the roles of SphK1 and SphK2 in the development/progression of hyperproliferative and/or inflammatory diseases.
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Affiliation(s)
- Jeremy A Hengst
- Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA 17033-0850, USA
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