DOCSLIB.ORG

Small Molecule Inhibition of Phosphatidylinositol- 3,4,5-Triphosphate (PIP3) Binding to Pleckstrin Homology Domains

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Small Molecule Inhibition of Phosphatidylinositol- 3,4,5-Triphosphate (PIP3) Binding to Pleckstrin Homology Domains Small molecule inhibition of phosphatidylinositol- 3,4,5-triphosphate (PIP3) binding to pleckstrin homology domains Benchun Miaoa,1, Igor Skidanb,1, Jinsheng Yangc, Alexey Lugovskoyd,2, Mikhail Reibarkhd, Kai Longe, Tres Brazella, Kulbhushan A. Durugkarf, Jenny Makia, C. V. Ramanaf, Brian Schaffhausena, Gerhard Wagnerd, Vladimir Torchilinb, Junying Yuane, and Alexei Degtereva,3 aDepartment of Biochemistry, Tufts University School of Medicine, Boston, MA 02111; bDepartment of Pharmaceutical Sciences, Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, Boston, MA 02115; cNeuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129; Departments of dBiological Chemistry and Molecular Pharmacology and eCell Biology, Harvard Medical School, Boston, MA 02115; and fNational Chemical Laboratory, Pune 411008, India Edited by Philip N. Tsichlis, Tufts Medical Center, Boston, MA, and accepted by the Editorial Board October 13, 2010 (received for review April 11, 2010) The PI3-kinase (PI3K) pathway regulates many cellular processes, downstream from growth factor and oncogene signals. A particu- especially cell metabolism, cell survival, and apoptosis. Phospha- larly important example of PIP3-dependent activation is that of tidylinositol-3,4,5-trisphosphate (PIP3), the product of PI3K activity serine-threonine kinase Akt. It is achieved both through the and a key signaling molecule, acts by recruiting pleckstrin-homology binding of Akt PH domain to PIP3 and membrane translocation of (PH) domain-containing proteins to cell membranes. Here, we de- another target of PIP3, PDK1, which phosphorylates and activates scribe a new structural class of nonphosphoinositide small molecule Akt. The Akt family plays a fundamental role in cell survival, antagonists (PITenins, PITs) of PIP3–PH domain interactions (IC50 growth, and energy metabolism (1, 7). ranges from 13.4 to 31 μM in PIP3/Akt PH domain binding assay). Although lipid–protein interactions mediate PI3K signaling and PITs inhibit interactions of a number of PIP3-binding PH domains, are frequently deregulated in cancer, most therapeutic strategies including those of Akt and PDK1, without affecting several PIP2- targeting the PI3K pathway have focused on inhibitors for down- selective PH domains. As a result, PITs suppress the PI3K-PDK1-Akt stream targets, including PDK1 (8) and Akt (9). Phospholipid– pathway and trigger metabolic stress and apoptosis. A PIT-1 analog protein interactions have not been as actively targeted, even displayed significant antitumor activity in vivo, including inhibition though lipid molecules are among the most important classes of of tumor growth and induction of apoptosis. Overall, our studies second messengers. It is surprising considering that they represent demonstrate the feasibility of developing specific small molecule “prototypic” small molecule–protein interactions usually involving antagonists of PIP3 signaling. well-defined binding sites (10). Conceptually, protein–lipid inter- actions may be more readily targetable compared with protein– PIP3 antagonist | anticancer protein interactions, which frequently involve interactions of ex- tended flat protein surfaces difficult to disrupt by small molecules. fi ysregulation of the phosphoinositide 3-kinase (PI3K) path- Here, we have pursued the identi cation of the small molecule Dway has been implicated in many human diseases. Hyper- antagonists of PIP3/protein binding. We report the discovery of activation of this pathway is known to play an important role in selective nonphosphoinositide PIP3 inhibitors, termed PITenins ≈ tumorigenesis, whereas deficiencies contribute to the development (PITs). PIT-1, selected in a screen of 50,000 small molecules by of type II diabetes. Therefore, this pathway offers promising tar- using a PIP3/Akt PH domain binding assay, has been extensively gets for the development of drugs to combat these diseases (1, 2). characterized. Our studies demonstrate that PIT-1 effectively fi Class I PI3Ks (α, β, and γ) are recruited to the plasma mem- inhibits cancer cell survival and induces cell apoptosis by speci - cally inhibiting PIP3-dependent PI3K-PDK1-Akt signaling, re- brane in response to growth factor and hormone stimulation fi to mediate the phosphorylation of lipid phosphatidylinositol- sulting in signi cant antitumor activity in vivo. Thus, we show not only a methodology usable to identify additional classes of 4,5-bisphosphate (PIP2), generating phosphatidylinositol-3,4,5- – trisphosphate (PIP3), which orchestrates multiple downstream phospholipid protein interactions, but also the feasibility of de- veloping cell-permeable specific small molecule nonlipid antago- intracellular signaling events (2). PIP3 signaling is terminated by – the phosphatase PTEN, which dephosphorylates PIP3. Genetic nists of lipid protein interactions. alterations targeting PTEN are among the most frequent muta- Results tions in human cancers, indicating a critical role of uncontrolled Identification of PIT-1 as a Specific PIP3 Antagonist. To identify signaling through PIP3 in tumorigenesis and metastasis (3). This compounds that disrupt the interaction between PIP3 and PH conclusion is reinforced by transgenic studies establishing that domains, we developed a high-throughput fluorescence polari- loss of PTEN leads to tumorigenesis (1). PIP3 controls a complex cellular signaling network regulating cell growth, proliferation, and survival. PIP3 target proteins are Author contributions: B.M., C.V.R., B.S., G.W., V.T., J.Y., and A.D. designed research; B.M., located in the cytosol of unstimulated cells and are recruited to the I.S., J.Y., A.L., M.R., K.L., T.B., K.A.D., and J.M. performed research; B.M., I.S., J.Y., A.L., membrane through pleckstrin-homology (PH) domain-mediated M.R., K.L., K.A.D., C.V.R., and A.D. analyzed data; and B.M. and A.D. wrote the paper. binding to newly formed PIP3. Membrane translocation and acti- The authors declare no conflict of interest. vation of the PIP3 target proteins initiate a variety of local re- This article is a PNAS Direct Submission. P.N.T. is a guest editor invited by the Editorial sponses, including assembly of signaling complexes and priming Board. of protein kinase cascades (1, 2). PIP3 regulates an array of PH 1B.M. and I.S. contributed equally to this work. domain-containing proteins (4), such as serine-threonine kinases 2Present address: Drug Discovery Department, Biogen IDEC Inc., 14 Cambridge Center, Akt and PDK1, GRP1, a GDP/GTP exchange factor of ADP Cambridge, MA 02142. ribosylating factor 6, and protein tyrosine kinases of the Bruton’s 3To whom correspondence should be addressed. E-mail: [email protected]. tyrosine kinase (Btk) and Tec families (5, 6). This diversity in PIP3 This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. signaling makes it one of the most important second messengers 1073/pnas.1004522107/-/DCSupplemental. 20126–20131 | PNAS | November 16, 2010 | vol. 107 | no. 46 www.pnas.org/cgi/doi/10.1073/pnas.1004522107 Downloaded by guest on September 29, 2021 zation (FP)-binding assay by using recombinant 1–123 amino acid binding of PI-3,4-P2 to Akt PH domain (Fig. S1H), consistent with N-terminal fragment of human Akt1, encompassing the PH do- the notion that PITs targeting Akt PH domain binding pocket, main (PH123 protein), and a fluorescent NBD-labeled PIP3 rather than a lipid. These data suggest that PIT-1 and PIT-2 rep- molecule. The R86A mutation in the PH domain, shown to disrupt resent unique nonphosphoinositide-related selective antagonists of PIP3–PH interaction (11), completely abrogated fluorescent PIP3 PIP3/PH domain binding. binding by PH123 (Fig. S1A), validating the assay. Our screen of To characterize the mode of action of PIT-1, we performed ≈50,000 diverse small molecules using this FP assay identified two NMR-based analysis of PIT-1 binding to the PH domain of Akt. We distinct inhibitors of PIP3/PH domain binding, which were termed found PIT-1 induces significant changes in the 2D HSQC 1H-15N PIT-1 and PIT-2 (Fig. 1A). These molecules disrupted PIP3/Akt correlation spectrum of Akt PH123, indicative of the direct PIT-1/ A PH domain binding with IC50 = 31.03 and 31.52 μM for PIT-1 and Akt PH domain binding (Fig. S2 ). We titrated Akt PH123 with PIT-2, respectively (Fig. 1B). Although giving similar results to PIT-1 to identify the residues affected by binding. Using published PIT-1, PIT-2 displayed limited stability and was used primarily to Akt2 HSQC peak assignments (13), we observed that the residues confirm the major conclusions. Analysis of commercial PIT-1 W22, Y26, and N54, located in the PIP3 binding pocket of the Akt analogs suggested that thiourea and hydroxyl groups are critical for PH domain, are affected by PIT-1. We found that PIT-1 had no the activity in vitro and revealed closely related inactive analogs of effect on the R86A PH domain mutant, which lacks PIP3 binding PIT-1, termed PIT-1i-1 and PIT-1i-2 (Fig. 1A), which have been activity, confirming the PIP3-mimetic nature of PIT-1. Using this used as negative controls. Besides the Akt PH domain, PIT-1 and information, we propose a binding model of PIT-1 on the surface of PIT-2 also inhibited the binding of PIP3 to the PH domains of the Akt PH domain in which the PIT-1 binding site overlaps with PDK1, GRP1, and ARNO with lower affinity (Fig. 1B and Fig. S1 the PIP3 binding site. Consistent with NMR data, W22 and Y26 B, C,andF) and failed to inhibit PIP3 binding to the PIP3-specific flank the RPR motif that interacts with the 3-phosphate of PIP3 PH domain of Btk (Fig. 1B and Fig. S1G). Thus, PITs exhibited and the nitro group of PIT-1, whereas N54 packs against the ter- selectivity toward a distinct subset of PIP3-specific PH domains. minal phenyl group of PIT-1 and does not interact with PIP3 (Fig. Furthermore, PITs failed to inhibit PIP2-specific interactions be- S2 B and C).
Load more

Recommended publications
  • Chemistry and Physics of Lipids Effects of Ether Vs. Ester Linkage On
    Chemistry and Physics of Lipids 160 (2009) 33–44 Contents lists available at ScienceDirect Chemistry and Physics of Lipids journal homepage: www.elsevier.com/locate/chemphyslip Effects of ether vs. ester linkage on lipid bilayer structure and water permeability S. Deren Guler a, D. Dipon Ghosh b, Jianjun Pan a, John C. Mathai c, Mark L. Zeidel c, John F. Nagle a,b, Stephanie Tristram-Nagle a,∗ a Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA b Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA c Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Cambridge, MA 02139, USA article info abstract Article history: The structure and water permeability of bilayers composed of the ether-linked lipid, dihexadecylphos- Received 29 January 2009 phatidylcholine (DHPC), were studied and compared with the ester-linked lipid, dipalmitoylphosphadit- Received in revised form 29 March 2009 dylcholine (DPPC). Wide angle X-ray scattering on oriented bilayers in the fluid phase indicate that the Accepted 26 April 2009 area per lipid A is slightly larger for DHPC than for DPPC. Low angle X-ray scattering yields A = 65.1 Å2 for Available online 3 May 2009 ◦ −13 DHPC at 48 C. LAXS data provide the bending modulus, KC = 4.2 × 10 erg, and the Hamaker parame- ter H =7.2× 10−14 erg for the van der Waals attractive interaction between neighboring bilayers. For the Keywords: low temperature phases with ordered hydrocarbon chains, we confirm the transition from a tilted L␤ Ether lipid ◦ gel phase to an untilted, interdigitated L␤I phase as the sample hydrates at 20 C.
    [Show full text]
  • Ras/Raf/MEK/ERK and PI3K/PTEN/Akt/Mtor Cascade Inhibitors: How Mutations Can Result in Therapy Resistance and How to Overcome Resistance
    www.impactjournals.com/oncotarget/ Oncotarget, October, Vol.3, No 10 Ras/Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR Cascade Inhibitors: How Mutations Can Result in Therapy Resistance and How to Overcome Resistance James A. McCubrey1, Linda S. Steelman1, William H. Chappell1, Stephen L. Abrams1, Richard A. Franklin1, Giuseppe Montalto2, Melchiorre Cervello3, Massimo Libra4, Saverio Candido4, Grazia Malaponte4, Maria C. Mazzarino4, Paolo Fagone4, Ferdinando Nicoletti4, Jörg Bäsecke5, Sanja Mijatovic6, Danijela Maksimovic- Ivanic6, Michele Milella7, Agostino Tafuri8, Francesca Chiarini9, Camilla Evangelisti9, Lucio Cocco10, Alberto M. Martelli9,10 1 Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, NC, USA 2 Department of Internal Medicine and Specialties, University of Palermo, Palermo, Italy 3 Consiglio Nazionale delle Ricerche, Istituto di Biomedicina e Immunologia Molecolare “Alberto Monroy”, Palermo, Italy 4 Department of Bio-Medical Sciences, University of Catania, Catania, Italy 5 Department of Medicine, University of Göttingen, Göttingen, Germany 6 Department of Immunology, Instititue for Biological Research “Sinisa Stankovic”, University of Belgrade, Belgrade, Serbia 7 Regina Elena National Cancer Institute, Rome, Italy 8 Sapienza, University of Rome, Department of Cellular Biotechnology and Hematology, Rome, Italy 9 Institute of Molecular Genetics, National Research Council-Rizzoli Orthopedic Institute, Bologna, Italy. 10 Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy Correspondence to: James A. McCubrey, email: [email protected] Keywords: Targeted Therapy, Therapy Resistance, Cancer Stem Cells, Raf, Akt, PI3K, mTOR Received: September 12, 2012, Accepted: October 18, 2012, Published: October 20, 2012 Copyright: © McCubrey et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
    [Show full text]
  • Mechanism and Management of AKT Inhibitor- Induced Hyperglycemia Ming-Chih Crouthamel,1Jason A
    Cancer Therapy: Preclinical Mechanism and Management of AKT Inhibitor- Induced Hyperglycemia Ming-Chih Crouthamel,1Jason A. Kahana,1Susan Korenchuk,1Shu-Yun Zhang,1 Gobalakrishnan Sundaresan,1DerekJ. Eberwein,1Kathleen K. Brown,2 andRakeshKumar1 Abstract Purpose: Insulin-like growth factor-I receptor and phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathways are among the most active areas of drug discovery in cancer research. However, due to their integral roles in insulin signaling, inhibitors targeting these pathways often lead to hyperglycemia and hyperinsulinemia. We investigated the mechanism of hyperglycemia induced by GSK690693, a pan-AKT kinase inhibitor in clinical development, as well as methods to ameliorate these side effects. Experimental Design:The effect of GSK690693 on blood glucose, insulin, and glucagon levels was characterized in mice. We then evaluated the effects of commonly prescribed antidiabetic agents on GSK690693-induced hyperglycemia. The mechanism of blood glucose increase was evaluated using fasting and tracer uptake studies and by measuring liver glycogen levels. Finally, approaches to manage AKT inhibitor-induced hyperglycemia were designed using fasting and low carbohydrate diet. Results: We report that treatment with antidiabetic agents does not significantly affect GSK690693-induced hyperglycemia in rodents. However, administration of GSK690693 in mice significantly reduces liver glycogen (f90%), suggesting that GSK690693 may inhibit glycogen synthesis and/or activate glycogenolysis. Consistent with this observation, fasting before drug administration reduces baseline liver glycogen levels and attenuates hyperglycemia. Further, GSK690693 also inhibits peripheral glucose uptake and introduction of a low-carbohydrate (7%) or 0% carbohydrate diet after GSK690693 administration effectively reduces diet-induced hyperglycemia in mice. Conclusions: The mechanism of GSK690693-induced hyperglycemia is related to peripheral insulin resistance, increased gluconeogenesis, and/or hepatic glycogenolysis.
    [Show full text]
  • Discovery of Inhibitors for the Ether Lipid-Generating Enzyme AGPS As Anti-Cancer Agents † # ‡ # § # † § Valentina Piano, , Daniel I
    Articles pubs.acs.org/acschemicalbiology Discovery of Inhibitors for the Ether Lipid-Generating Enzyme AGPS as Anti-Cancer Agents † # ‡ # § # † § Valentina Piano, , Daniel I. Benjamin, , Sergio Valente, , Simone Nenci, Biagina Marrocco, § ∥ ⊥ ‡ † Antonello Mai, , Alessandro Aliverti, Daniel K. Nomura,*, and Andrea Mattevi*, † Department of Biology and Biotechnology, University of Pavia, via Ferrata 9, 27100 Pavia, Italy ‡ Program in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, California 94720, United States § Department of Drug Chemistry and Technologies, University “La Sapienza”, P. le A. Moro 5, Roma 00185, Italy ∥ Pasteur Institute, Cenci Bolognetti Foundation, P.le A. Moro 5, Roma 00185, Italy ⊥ Department of Biosciences, University of Milano, Via Festa del Perdono, 7, 20122 Milano, Italy *S Supporting Information ABSTRACT: Dysregulated ether lipid metabolism is an important hallmark of cancer cells. Previous studies have reported that lowering ether lipid levels by genetic ablation of the ether lipid-generating enzyme alkyl-glycerone phosphate synthase (AGPS) lowers key structural and oncogenic ether lipid levels and alters fatty acid, glycerophospholipid, and eicosanoid metabolism to impair cancer pathogenicity, indicating that AGPS may be a potential therapeutic target for cancer. In this study, we have performed a small-molecule screen to identify candidate AGPS inhibitors. We have identified several lead AGPS inhibitors and have structurally characterized their interactions with the enzyme and show that these inhibitors bind to distinct portions of the active site. We further show that the lead AGPS inhibitor 1a selectively lowers ether lipid levels in several types of human cancer cells and impairs their cellular survival and migration. We provide here the first report of in situ-active pharmacological tools for inhibiting AGPS, which may provide chemical scaffolds for future AGPS inhibitor development for cancer therapy.
    [Show full text]
  • Hot Topics in Neural Membrane Lipidology
    A.A. Farooqui Hot Topics in Neural Membrane Lipidology ▶ Focuses exclusively on lipid mediators and neurological disorders Not only do glycerophospholipid, sphingolipid, and cholesterol-derived lipid mediators facilitate the transfer of messages from one cell to another, they also facilitate communication among subcellular organelles. Hot Topics in Neural Membrane Lipidology provides readers with a cutting-edge, comprehensive review of these lipid mediators, their roles and association with neurological disorders, and the future direction of research on the topic. This monograph provides readers with critical data and is particularly accessible to neuroscience graduate students, teachers, and researchers. It can be used as a supplemental text for a range of neuroscience courses. Clinicians and pharmacologists will find this book useful for understanding molecular aspects of lipid mediators in acute neural trauma like stroke, spinal cord trauma, head injury, and neurodegenerative diseases such as Alzheimer disease, Parkinson disease, and Huntington disease. 2009, XXIV, 408 p. 62 illus. About the Author: Printed book Akhlaq A. Farooqui is a leader in the field of brain phospholipases A2, bioactive ether lipid metabolism, and glutamate-mediated neurotoxicity. He has discovered the stimulation of Hardcover plasmalogen-selective phospholipase A2 activity in brains from patients with Alzheimer ▶ 199,99 € | £179.99 | $249.99 disease, and published cutting edge research on the generation and identification of ▶ *213,99 € (D) | 219,99 € (A) | CHF 236.00 glycerophospholipid, sphingolipid, and cholesterol-derived lipid mediators in kainic acid neurotoxicity. Dr. Farooqui has authored three monographs: Glycerophospholipids eBook in Brain: Phospholipase A2 in Neurological Disorders (2007); Neurochemical Aspects of Excitotoxicity (2008); and Metabolism and Functions of Bioactive Ether Lipids in Brain Available from your bookstore or (2008).
    [Show full text]
  • The Ether Lipid-Deficient Mouse: Tracking Down Plasmalogen Functions ⁎ Karin Gorgas A, Andre Teigler B, Dorde Komljenovic A, Wilhelm W
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Biochimica et Biophysica Acta 1763 (2006) 1511–1526 www.elsevier.com/locate/bbamcr Review The ether lipid-deficient mouse: Tracking down plasmalogen functions ⁎ Karin Gorgas a, Andre Teigler b, Dorde Komljenovic a, Wilhelm W. Just b, a Institut für Anatomie und Zellbiologie, Abteilung Medizinische Zellbiologie, Im Neuenheimer Feld 307, D-69120 Heidelberg, Germany b Biochemie-Zentrum der Universität Heidelberg (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany Received 29 June 2006; received in revised form 15 August 2006; accepted 23 August 2006 Available online 30 August 2006 Abstract Chemical and physico-chemical properties as well as physiological functions of major mammalian ether-linked glycerolipids, including plasmalogens were reviewed. Their chemical structures were described and their effect on membrane fluidity and membrane fusion discussed. The recent generation of mouse models with ether lipid deficiency offered the possibility to study ether lipid and particularly plasmalogen functions in vivo. Ether lipid-deficient mice revealed severe phenotypic alterations, including arrest of spermatogenesis, development of cataract and defects in central nervous system myelination. In several cell culture systems lack of plasmalogens impaired intracellular cholesterol distribution affecting plasma membrane functions and structural changes of ER and Golgi cisternae. Based on these phenotypic anomalies that were accurately described conclusions were drawn on putative functions of plasmalogens. These functions were related to cell–cell or cell–extracellular matrix interactions, formation of lipid raft microdomains and intracellular cholesterol homeostasis. There are several human disorders, such as Zellweger syndrome, rhizomelic chondrodysplasia punctata, Alzheimer’s disease, Down syndrome, and Niemann–Pick type C disease that are distinguished by altered tissue plasmalogen concentrations.
    [Show full text]
  • A Novel Oncolytic Herpes Simplex Virus That Synergizes with Phosphoinositide 3-Kinase/Akt Pathway Inhibitors to Target Glioblastoma Stem Cells
    Published OnlineFirst April 19, 2011; DOI: 10.1158/1078-0432.CCR-10-3142 Clinical Cancer Cancer Therapy: Preclinical Research A Novel Oncolytic Herpes Simplex Virus that Synergizes with Phosphoinositide 3-kinase/Akt Pathway Inhibitors to Target Glioblastoma Stem Cells Ryuichi Kanai, Hiroaki Wakimoto, Robert L. Martuza, and Samuel D. Rabkin Abstract Purpose: To develop a new oncolytic herpes simplex virus (oHSV) for glioblastoma (GBM) therapy that will be effective in glioblastoma stem cells (GSC), an important and untargeted component of GBM. One approach to enhance oHSV efficacy is by combination with other therapeutic modalities. Experimental Design: MG18L, containing a US3 deletion and an inactivating LacZ insertion in UL39, was constructed for the treatment of brain tumors. Safety was evaluated after intracerebral injection in HSV- susceptible mice. The efficacy of MG18L in human GSCs and glioma cell lines in vitro was compared with other oHSVs, alone or in combination with phosphoinositide-3-kinase (PI3K)/Akt inhibitors (LY294002, triciribine, GDC-0941, and BEZ235). Cytotoxic interactions between MG18L and PI3K/Akt inhibitors were determined using Chou–Talalay analysis. In vivo efficacy studies were conducted using a clinically relevant mouse model of GSC-derived GBM. Results: MG18L was severely neuroattenuated in mice, replicated well in GSCs, and had anti-GBM activity in vivo. PI3K/Akt inhibitors displayed significant but variable antiproliferative activities in GSCs, whereas their combination with MG18L synergized in killing GSCs and glioma cell lines, but not human astrocytes, through enhanced induction of apoptosis. Importantly, synergy was independent of inhibitor sensitivity. In vivo, the combination of MG18L and LY294002 significantly prolonged survival of mice, as compared with either agent alone, achieving 50% long-term survival in GBM-bearing mice.
    [Show full text]
  • The Survival Kinases Akt and Pim As Potential Pharmacological Targets
    The survival kinases Akt and Pim as potential pharmacological targets Ravi Amaravadi, Craig B. Thompson J Clin Invest. 2005;115(10):2618-2624. https://doi.org/10.1172/JCI26273. Review Series The Akt and Pim kinases are cytoplasmic serine/threonine kinases that control programmed cell death by phosphorylating substrates that regulate both apoptosis and cellular metabolism. The PI3K-dependent activation of the Akt kinases and the JAK/STAT–dependent induction of the Pim kinases are examples of partially overlapping survival kinase pathways. Pharmacological manipulation of such kinases could have a major impact on the treatment of a wide variety of human diseases including cancer, inflammatory disorders, and ischemic diseases. Find the latest version: https://jci.me/26273/pdf Review series The survival kinases Akt and Pim as potential pharmacological targets Ravi Amaravadi and Craig B. Thompson Abramson Family Cancer Research Institute, Department of Cancer Biology and Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA. The Akt and Pim kinases are cytoplasmic serine/threonine kinases that control programmed cell death by phos- phorylating substrates that regulate both apoptosis and cellular metabolism. The PI3K-dependent activation of the Akt kinases and the JAK/STAT–dependent induction of the Pim kinases are examples of partially overlapping sur- vival kinase pathways. Pharmacological manipulation of such kinases could have a major impact on the treatment of a wide variety of human diseases including cancer, inflammatory disorders, and ischemic diseases. Introduction allow myc to act as an oncogene, leading to a malignant phe- There is increasing evidence that serine/threonine kinases exist notype. While deficiency in the tumor suppressor gene p53 and that directly regulate cell survival.
    [Show full text]
  • Bioactive Ether Lipids: Primordial Modulators of Cellular Signaling
    H OH metabolites OH Review Bioactive Ether Lipids: Primordial Modulators of Cellular Signaling Nikhil Rangholia 1,† , Tina M. Leisner 2 and Stephen P. Holly 1,* 1 Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Campbell University, Buies Creek, NC 27506, USA; [email protected] 2 Eshelman School of Pharmacy, Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; [email protected] * Correspondence: [email protected] † Current address: Frontage Laboratories Inc., 75 E. Uwchian Ave, STE 100, Exton, PA 19341, USA. Abstract: The primacy of lipids as essential components of cellular membranes is conserved across taxonomic domains. In addition to this crucial role as a semi-permeable barrier, lipids are also increasingly recognized as important signaling molecules with diverse functional mechanisms ranging from cell surface receptor binding to the intracellular regulation of enzymatic cascades. In this review, we focus on ether lipids, an ancient family of lipids having ether-linked structures that chemically differ from their more prevalent acyl relatives. In particular, we examine ether lipid biosynthesis in the peroxisome of mammalian cells, the roles of selected glycerolipids and glycerophospholipids in signal transduction in both prokaryotes and eukaryotes, and finally, the potential therapeutic contributions of synthetic ether lipids to the treatment of cancer. Keywords: ether lipid; alkylglycerol; signaling; signal transduction; glycerolipid; glycerophospho- lipid; apoptosis; platelet; cancer 1. Introduction Citation: Rangholia, N.; Leisner, Much like many other types of organic molecules, lipids are essential for life—even T.M.; Holly, S.P.
    [Show full text]
  • Antiproliferative Effect of Two Novel Palmitoylcarnitine Analogs
    Eur. J. Biochem. 266, 855±864 (1999) q FEBS 1999 Anti-proliferative effect of two novel palmitoyl-carnitine analogs, selective inhibitors of protein kinase C conventional isoenzymes Tea Garcia-Huidobro, Enrique Valenzuela, Andrea V. Leisewitz, Jaime Valderrama and Miguel Bronfman Departamento de BiologõÂa Celular y Molecular, Facultad de Ciencias BioloÂgicas y Facultad de QuõÂmica, P. Universidad CatoÂlica de Chile, Santiago, Chile Previous studies have shown that palmitoyl-carnitine is an anti-proliferative agent and a protein kinase C inhibitor. Two new palmitoyl-carnitine analogs were synthesized by replacing the ester bond with a metabolically more stable ether bond. An LD50 value in the nm range was found in anti-proliferative assays using HL-60 cells and was dependent on the alkyl-chain length. The inhibitory action of these water-soluble compounds on protein kinase C in vitro was greatly increased with respect to palmitoyl-carnitine and was dependent on the length of the alkyl chain. Its effect was mediated by an increase in the enzyme's requirement for phosphatidylserine. Inhibition of the in situ phosphorylation of a physiological platelet protein kinase C substrate and of phorbol ester-induced differentiation of HL-60 cells was also observed. Finally, to test for isoenzyme selectivity, several human recombinant protein kinase C isoforms were used. Only the Ca2+-dependent classic protein kinase Cs (a, bI, bII and g) were inhibited by these compounds, yet the activities of casein kinase I, Ca2+/calmodulin-dependent kinase and cAMP-dependent protein kinase were unaffected. Thus, these novel inhibitors appear to be both protein kinase C and isozyme selective.
    [Show full text]
  • The TMEM189 Gene Encodes Plasmanylethanolamine Desaturase Which Introduces the Characteristic Vinyl Ether Double Bond Into Plasmalogens
    The TMEM189 gene encodes plasmanylethanolamine desaturase which introduces the characteristic vinyl ether double bond into plasmalogens Ernst R. Wernera,1, Markus A. Kellerb, Sabrina Sailera, Katharina Lacknera, Jakob Kochb, Martin Hermannc, Stefan Coassind, Georg Golderera, Gabriele Werner-Felmayera, Raphael A. Zoellere, Nicolas Hulof, Johannes Bergerg, and Katrin Watschingera,1 aInstitute of Biological Chemistry, Biocenter, Medical University of Innsbruck, A-6020 Innsbruck, Austria; bInstitute of Human Genetics, Medical University of Innsbruck, A-6020 Innsbruck, Austria; cUniversity Clinic for Anesthesiology and General Intensive Care Medicine, Medical University of Innsbruck, A-6020 Innsbruck, Austria; dInstitute of Genetic Epidemiology, Department of Genetics and Pharmacology, Medical University of Innsbruck, A-6020 Innsbruck, Austria; eDepartment of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118; fInstitute of Genetics and Genomics, University of Geneva, 1211 Geneva 4, Switzerland; and gDepartment of Pathobiology of the Nervous System, Medical University of Vienna, 1090 Vienna, Austria Edited by Benjamin F. Cravatt, Scripps Research Institute, La Jolla, CA, and approved February 26, 2020 (received for review October 7, 2019) A significant fraction of the glycerophospholipids in the human body severe clinical outcomes, including impaired neural development, is composed of plasmalogens, particularly in the brain, cardiac, and bone deformation, and premature death. The initial peroxisomal immune cell membranes. A decline in these lipids has been observed steps of human plasmalogen biosynthesis have been well charac- in such diseases as Alzheimer’s and chronic obstructive pulmonary terized to require the genes GNPAT (11, 12), AGPS (13), and disease. Plasmalogens contain a characteristic 1-O-alk-1′-enyl ether DHRS7B (14). Further downstream steps occurring in the en- (vinyl ether) double bond that confers special biophysical, biochemi- doplasmic reticulum are less well understood, however.
    [Show full text]
  • The TMEM189 Gene Encodes Plasmanylethanolamine Desaturase Which Introduces the Characteristic Vinyl Ether Double Bond Into Plasmalogens
    The TMEM189 gene encodes plasmanylethanolamine desaturase which introduces the characteristic vinyl ether double bond into plasmalogens Ernst R. Wernera,1, Markus A. Kellerb, Sabrina Sailera, Katharina Lacknera, Jakob Kochb, Martin Hermannc, Stefan Coassind, Georg Golderera, Gabriele Werner-Felmayera, Raphael A. Zoellere, Nicolas Hulof, Johannes Bergerg, and Katrin Watschingera,1 aInstitute of Biological Chemistry, Biocenter, Medical University of Innsbruck, A-6020 Innsbruck, Austria; bInstitute of Human Genetics, Medical University of Innsbruck, A-6020 Innsbruck, Austria; cUniversity Clinic for Anesthesiology and General Intensive Care Medicine, Medical University of Innsbruck, A-6020 Innsbruck, Austria; dInstitute of Genetic Epidemiology, Department of Genetics and Pharmacology, Medical University of Innsbruck, A-6020 Innsbruck, Austria; eDepartment of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118; fInstitute of Genetics and Genomics, University of Geneva, 1211 Geneva 4, Switzerland; and gDepartment of Pathobiology of the Nervous System, Medical University of Vienna, 1090 Vienna, Austria Edited by Benjamin F. Cravatt, Scripps Research Institute, La Jolla, CA, and approved February 26, 2020 (received for review October 7, 2019) A significant fraction of the glycerophospholipids in the human body severe clinical outcomes, including impaired neural development, is composed of plasmalogens, particularly in the brain, cardiac, and bone deformation, and premature death. The initial peroxisomal immune cell membranes. A decline in these lipids has been observed steps of human plasmalogen biosynthesis have been well charac- in such diseases as Alzheimer’s and chronic obstructive pulmonary terizedtorequirethegenesGNPAT (11, 12), AGPS (13), and disease. Plasmalogens contain a characteristic 1-O-alk-1′-enyl ether DHRS7B (14). Further downstream steps occurring in the en- (vinyl ether) double bond that confers special biophysical, biochemi- doplasmic reticulum are less well understood, however.
    [Show full text]