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De Vecchis D, Schäfer LV. Coupling the role of lipids to the conformational dynamics of the ABC transporter P-glycoprotein. Biophys J 2024:S0006-3495(24)00417-X. [PMID: 38909280 DOI: 10.1016/j.bpj.2024.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/31/2024] [Accepted: 06/18/2024] [Indexed: 06/24/2024] Open
Abstract
The ATP-binding cassette transporter P-glycoprotein (P-gp) is a multidrug efflux pump that is overexpressed in a variety of cancers and associated with the drug-resistance phenomenon. P-gp structures were previously determined in detergent and in nanodiscs, in which different transmembrane helix conformations were found, "straight" and "kinked," respectively, indicating a possible role of the lipid environment on the P-gp structural ensemble. Here, we investigate the dynamic conformational ensembles and protein-lipid interactions of two human P-gp inward-open conformers, straight and kinked, employing all-atom molecular dynamics (MD) simulations in asymmetric multicomponent lipid bilayers that mimic the highly specialized hepatocyte membrane in which P-gp is expressed. The two conformers are found to differ in terms of the accessibility of the substrate cavity. The MD simulations show how cholesterol and different lipid species wedge, snorkel, and partially enter into the cavity of the straight P-gp conformer solved in detergent. However, access to the cavity of the kinked P-gp conformer solved in nanodiscs is restricted. Furthermore, the volume and dynamic fluctuations of the substrate cavity largely differ between the two P-gp conformers and are modulated by the presence (or absence) of cholesterol in the membrane and/or of ATP. From the mechanistic perspective, the findings indicate that the straight conformer likely precedes the kinked conformer in the functional working cycle of P-gp, with the latter conformation representing a post substrate-bound state. The inaccessibility of the main transmembrane cavity in the kinked conformer might be crucial in preventing substrate disengagement and transport withdrawal. Remarkably, in our unbiased MD simulations, one transmembrane helix (TM10) of the straight conformer underwent a spontaneous transition to a kinked conformation, underlining the relevance of both conformations in a native phospholipid environment and revealing structural descriptors defining the transition between the two P-gp conformers.
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Affiliation(s)
- Dario De Vecchis
- Center for Theoretical Chemistry, Ruhr University Bochum, Bochum, Germany.
| | - Lars V Schäfer
- Center for Theoretical Chemistry, Ruhr University Bochum, Bochum, Germany.
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2
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Thévenod F, Lee WK. Cadmium transport by mammalian ATP-binding cassette transporters. Biometals 2024; 37:697-719. [PMID: 38319451 PMCID: PMC11101381 DOI: 10.1007/s10534-024-00582-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 01/04/2024] [Indexed: 02/07/2024]
Abstract
Cellular responses to toxic metals depend on metal accessibility to intracellular targets, reaching interaction sites, and the intracellular metal concentration, which is mainly determined by uptake pathways, binding/sequestration and efflux pathways. ATP-binding cassette (ABC) transporters are ubiquitous in the human body-usually in epithelia-and are responsible for the transfer of indispensable physiological substrates (e.g. lipids and heme), protection against potentially toxic substances, maintenance of fluid composition, and excretion of metabolic waste products. Derailed regulation and gene variants of ABC transporters culminate in a wide array of pathophysiological disease states, such as oncogenic multidrug resistance or cystic fibrosis. Cadmium (Cd) has no known physiological role in mammalians and poses a health risk due to its release into the environment as a result of industrial activities, and eventually passes into the food chain. Epithelial cells, especially within the liver, lungs, gastrointestinal tract and kidneys, are particularly susceptible to the multifaceted effects of Cd because of the plethora of uptake pathways available. Pertinent to their broad substrate spectra, ABC transporters represent a major cellular efflux pathway for Cd and Cd complexes. In this review, we summarize current knowledge concerning transport of Cd and its complexes (mainly Cd bound to glutathione) by the ABC transporters ABCB1 (P-glycoprotein, MDR1), ABCB6, ABCC1 (multidrug resistance related protein 1, MRP1), ABCC7 (cystic fibrosis transmembrane regulator, CFTR), and ABCG2 (breast cancer related protein, BCRP). Potential detoxification strategies underlying ABC transporter-mediated efflux of Cd and Cd complexes are discussed.
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Affiliation(s)
- Frank Thévenod
- Institute for Physiology, Pathophysiology and Toxicology & ZBAF, Witten/Herdecke University, 58453, Witten, Germany
- Physiology and Pathophysiology of Cells and Membranes, Medical School OWL, Bielefeld University, Morgenbreede 1, 33615, Bielefeld, Germany
| | - Wing-Kee Lee
- Physiology and Pathophysiology of Cells and Membranes, Medical School OWL, Bielefeld University, Morgenbreede 1, 33615, Bielefeld, Germany.
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3
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Herrera SA, Günther Pomorski T. Reconstitution of ATP-dependent lipid transporters: gaining insight into molecular characteristics, regulation, and mechanisms. Biosci Rep 2023; 43:BSR20221268. [PMID: 37417269 PMCID: PMC10412526 DOI: 10.1042/bsr20221268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/30/2023] [Accepted: 07/06/2023] [Indexed: 07/08/2023] Open
Abstract
Lipid transporters play a crucial role in supporting essential cellular processes such as organelle assembly, vesicular trafficking, and lipid homeostasis by driving lipid transport across membranes. Cryo-electron microscopy has recently resolved the structures of several ATP-dependent lipid transporters, but functional characterization remains a major challenge. Although studies of detergent-purified proteins have advanced our understanding of these transporters, in vitro evidence for lipid transport is still limited to a few ATP-dependent lipid transporters. Reconstitution into model membranes, such as liposomes, is a suitable approach to study lipid transporters in vitro and to investigate their key molecular features. In this review, we discuss the current approaches for reconstituting ATP-driven lipid transporters into large liposomes and common techniques used to study lipid transport in proteoliposomes. We also highlight the existing knowledge on the regulatory mechanisms that modulate the activity of lipid transporters, and finally, we address the limitations of the current approaches and future perspectives in this field.
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Affiliation(s)
- Sara Abad Herrera
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
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4
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Yazlovitskaya EM, Graham TR. Type IV P-Type ATPases: Recent Updates in Cancer Development, Progression, and Treatment. Cancers (Basel) 2023; 15:4327. [PMID: 37686603 PMCID: PMC10486736 DOI: 10.3390/cancers15174327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/15/2023] [Accepted: 08/28/2023] [Indexed: 09/10/2023] Open
Abstract
Adaptations of cancer cells for survival are remarkable. One of the most significant properties of cancer cells to prevent the immune system response and resist chemotherapy is the altered lipid metabolism and resulting irregular cell membrane composition. The phospholipid distribution in the plasma membrane of normal animal cells is distinctly asymmetric. Lipid flippases are a family of enzymes regulating membrane asymmetry, and the main class of flippases are type IV P-type ATPases (P4-ATPases). Alteration in the function of flippases results in changes to membrane organization. For some lipids, such as phosphatidylserine, the changes are so drastic that they are considered cancer biomarkers. This review will analyze and discuss recent publications highlighting the role that P4-ATPases play in the development and progression of various cancer types, as well as prospects of targeting P4-ATPases for anti-cancer treatment.
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Affiliation(s)
| | - Todd R. Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
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5
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Skinner KT, Palkar AM, Hong AL. Genetics of ABCB1 in Cancer. Cancers (Basel) 2023; 15:4236. [PMID: 37686513 PMCID: PMC10487083 DOI: 10.3390/cancers15174236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/10/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
ABCB1, also known as MDR1, is a gene that encodes P-glycoprotein (P-gp), a membrane-associated ATP-dependent transporter. P-gp is widely expressed in many healthy tissues-in the gastrointestinal tract, liver, kidney, and at the blood-brain barrier. P-gp works to pump xenobiotics such as toxins and drugs out of cells. P-gp is also commonly upregulated across multiple cancer types such as ovarian, breast, and lung. Overexpression of ABCB1 has been linked to the development of chemotherapy resistance across these cancers. In vitro work across a wide range of drug-sensitive and -resistant cancer cell lines has shown that upon treatment with chemotherapeutic agents such as doxorubicin, cisplatin, and paclitaxel, ABCB1 is upregulated. This upregulation is caused in part by a variety of genetic and epigenetic mechanisms. This includes single-nucleotide variants that lead to enhanced P-gp ATPase activity without increasing ABCB1 RNA and protein levels. In this review, we summarize current knowledge of genetic and epigenetic mechanisms leading to ABCB1 upregulation and P-gp-enhanced ATPase activity in the setting of chemotherapy resistance across a variety of cancers.
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Affiliation(s)
- Katie T. Skinner
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA; (K.T.S.); (A.M.P.)
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Antara M. Palkar
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA; (K.T.S.); (A.M.P.)
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Andrew L. Hong
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA; (K.T.S.); (A.M.P.)
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
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6
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Gutay-Tóth Z, Gellen G, Doan M, Eliason JF, Vincze J, Szente L, Fenyvesi F, Goda K, Vecsernyés M, Szabó G, Bacso Z. Cholesterol-Depletion-Induced Membrane Repair Carries a Raft Conformer of P-Glycoprotein to the Cell Surface, Indicating Enhanced Cholesterol Trafficking in MDR Cells, Which Makes Them Resistant to Cholesterol Modifications. Int J Mol Sci 2023; 24:12335. [PMID: 37569709 PMCID: PMC10419235 DOI: 10.3390/ijms241512335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 07/26/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
The human P-glycoprotein (P-gp), a transporter responsible for multidrug resistance, is present in the plasma membrane's raft and non-raft domains. One specific conformation of P-gp that binds to the monoclonal antibody UIC2 is primarily associated with raft domains and displays heightened internalization in cells overexpressing P-gp, such as in NIH-3T3 MDR1 cells. Our primary objective was to investigate whether the trafficking of this particular P-gp conformer is dependent on cholesterol levels. Surprisingly, depleting cholesterol using cyclodextrin resulted in an unexpected increase in the proportion of raft-associated P-gp within the cell membrane, as determined by UIC2-reactive P-gp. This increase appears to be a compensatory response to cholesterol loss from the plasma membrane, whereby cholesterol-rich raft micro-domains are delivered to the cell surface through an augmented exocytosis process. Furthermore, this exocytotic event is found to be part of a complex trafficking mechanism involving lysosomal exocytosis, which contributes to membrane repair after cholesterol reduction induced by cyclodextrin treatment. Notably, cells overexpressing P-gp demonstrated higher total cellular cholesterol levels, an increased abundance of stable lysosomes, and more effective membrane repair following cholesterol modifications. These modifications encompassed exocytotic events that involved the transport of P-gp-carrying rafts. Importantly, the enhanced membrane repair capability resulted in a durable phenotype for MDR1 expressing cells, as evidenced by significantly improved viabilities of multidrug-resistant Pgp-overexpressing immortal NIH-3T3 MDR1 and MDCK-MDR1 cells compared to their parents when subjected to cholesterol alterations.
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Affiliation(s)
- Zsuzsanna Gutay-Tóth
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - Gabriella Gellen
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Department of Analytical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, 1053 Budapest, Hungary
| | - Minh Doan
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
| | - James F. Eliason
- Great Lakes Stem Cell Innovation Center, Detroit, MI 48202, USA;
| | - János Vincze
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary;
| | - Lajos Szente
- CycloLab Cyclodextrin Research & Development Laboratory, Ltd., 1097 Budapest, Hungary;
| | - Ferenc Fenyvesi
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary; (F.F.); (M.V.)
| | - Katalin Goda
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
| | - Miklós Vecsernyés
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary; (F.F.); (M.V.)
| | - Gábor Szabó
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
| | - Zsolt Bacso
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary; (F.F.); (M.V.)
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7
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Clark LE, Dickinson AJG, Lima S. GBA Regulates EMT/MET and Chemoresistance in Squamous Cell Carcinoma Cells by Modulating the Cellular Glycosphingolipid Profile. Cells 2023; 12:1886. [PMID: 37508550 PMCID: PMC10378370 DOI: 10.3390/cells12141886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/13/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Glycosphingolipids (GSL) are plasma membrane components that influence molecular processes involved in cancer initiation, progression, and therapeutic responses. They also modulate receptor tyrosine kinases involved in EMT. Therefore, understanding the mechanisms that regulate GSLs in cancer has important therapeutic potential. One critical regulator of GSLs is the lysosomal glucosylceramidase β1 (GBA) that catalyzes the last step in GSL degradation. We show that, in cancer, GBA copy number amplifications and increased expression are widespread. We show that depleting GBA in squamous cell carcinoma cell lines results in a mesenchymal-to-epithelial shift, decreased invasion and migration, increased chemotherapeutic sensitivity, and decreased activation of receptor tyrosine kinases that are involved in regulating EMT. Untargeted lipidomics shows that GBA depletion had significant effects on sphingolipids and GSLs, suggesting that increased GBA activity in cancer sustains EMT and chemoresistance by modulating receptor tyrosine kinase activity and signaling via effects on the cellular lipid profile.
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Affiliation(s)
- Laura E Clark
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Amanda J G Dickinson
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Santiago Lima
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284, USA
- Massey Cancer Center, Richmond, VA 23298, USA
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8
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Kalave S, Hegde N, Juvale K. Applications of Nanotechnology-based Approaches to Overcome Multi-drug Resistance in Cancer. Curr Pharm Des 2022; 28:3140-3157. [PMID: 35366765 DOI: 10.2174/1381612828666220401142300] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 02/27/2022] [Indexed: 01/28/2023]
Abstract
Cancer is one of the leading causes of death worldwide. Chemotherapy and radiation therapy are the major treatments used for the management of cancer. Multidrug resistance (MDR) is a major hindrance faced in the treatment of cancer and is also responsible for cancer relapse. To date, several studies have been carried out on strategies to overcome or reverse MDR in cancer. Unfortunately, the MDR reversing agents have been proven to have minimal clinical benefits, and eventually, no improvement has been made in therapeutic efficacy to date. Thus, several investigational studies have also focused on overcoming drug resistance rather than reversing the MDR. In this review, we focus primarily on nanoformulations regarded as a novel approach to overcome or bypass the MDR in cancer. The nanoformulation systems serve as an attractive strategy as these nanosized materials selectively get accumulated in tumor tissues, thereby improving the clinical outcomes of patients suffering from MDR cancer. In the current work, we present an overview of recent trends in the application of various nano-formulations, belonging to different mechanistic classes and functionalization like carbon nanotubes, carbon nanohorns, carbon nanospheres, liposomes, dendrimers, etc., to overcome MDR in cancer. A detailed overview of these techniques will help researchers in exploring the applicability of nanotechnologybased approaches to treat MDR.
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Affiliation(s)
- Sana Kalave
- Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKM's NMIMS, V.L. Mehta Road, Vile Parle [W], Mumbai, India
| | - Namita Hegde
- Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKM's NMIMS, V.L. Mehta Road, Vile Parle [W], Mumbai, India
| | - Kapil Juvale
- Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKM's NMIMS, V.L. Mehta Road, Vile Parle [W], Mumbai, India
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9
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Exploration of novel phthalazinone derivatives as potential efflux transporter inhibitors for reversing multidrug resistance and improving the oral absorption of paclitaxel. Eur J Med Chem 2022; 233:114231. [PMID: 35247755 DOI: 10.1016/j.ejmech.2022.114231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 11/23/2022]
Abstract
Chemotherapy is an important means of cancer treatment. However, overexpression of efflux transporters (including but not limited to P-gp and BCRP) can lead to resistance to cancer chemotherapy. Multiple-target inhibitors of efflux transporter can be overcome the resistance and improve the oral bioavailability of chemotherapy drugs. Therefore, we designed and synthesized a series of phthalazinone ring derivatives (1-20) with different aromatic heterocycles substituents on the amide bond for dual inhibition of P-gp and BCRP. Most target compounds significantly increased the accumulation of P-gp substrates in the chemo-resistant cancer cell lines by inhibiting the efflux of transporters. Compound 19 in particular showed stronger MDR reversal compared to Gefitinib and Verapamil, and comparable to that of the BCRP inhibitor Ko143. In addition, compound 19 improved intestinal absorption of paclitaxel (PTX) and enhanced the bioavailability of the orally administered drug in vivo.
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10
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Nolte W, Weikard R, Albrecht E, Hammon HM, Kühn C. Metabogenomic analysis to functionally annotate the regulatory role of long non-coding RNAs in the liver of cows with different nutrient partitioning phenotype. Genomics 2021; 114:202-214. [PMID: 34923089 DOI: 10.1016/j.ygeno.2021.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 07/26/2021] [Accepted: 12/13/2021] [Indexed: 11/17/2022]
Abstract
Long non-coding RNAs (lncRNAs) hold gene regulatory potential, but require substantial further functional annotation in livestock. Applying two metabogenomic approaches by combining transcriptomic and metabolomic analyses, we aimed to identify lncRNAs with potential regulatory function for divergent nutrient partitioning of lactating crossbred cows and to establish metabogenomic interaction networks comprising metabolites, genes and lncRNAs. Through correlation analysis of lncRNA expression with transcriptomic and metabolomic data, we unraveled lncRNAs that have a putative regulatory role in energy and lipid metabolism, the urea and tricarboxylic acid cycles, and gluconeogenesis. Especially FGF21, which correlated with a plentitude of differentially expressed genes, differentially abundant metabolites, as well as lncRNAs, suggested itself as a key metabolic regulator. Notably, lncRNAs in close physical proximity to coding-genes as well as lncRNAs with natural antisense transcripts appear to perform a fine-tuning function in gene expression involved in metabolic pathways associated with different nutrient partitioning phenotypes.
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Affiliation(s)
- Wietje Nolte
- Institute of Genome Biology, Research Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany
| | - Rosemarie Weikard
- Institute of Genome Biology, Research Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany
| | - Elke Albrecht
- Institute of Muscle Biology and Growth, Research Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany
| | - Harald M Hammon
- Institute of Nutritional Physiology "Oskar Kellner", Research Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany
| | - Christa Kühn
- Institute of Genome Biology, Research Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; Faculty of Agricultural and Environmental Sciences, University Rostock, 18059 Rostock, Germany.
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11
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Budani M, Auray-Blais C, Lingwood C. ATP-binding cassette transporters mediate differential biosynthesis of glycosphingolipid species. J Lipid Res 2021; 62:100128. [PMID: 34597626 PMCID: PMC8569594 DOI: 10.1016/j.jlr.2021.100128] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 08/18/2021] [Accepted: 09/03/2021] [Indexed: 01/13/2023] Open
Abstract
The cytosolic-oriented glucosylceramide (GlcCer) synthase is enigmatic, requiring nascent GlcCer translocation to the luminal Golgi membrane to access glycosphingolipid (GSL) anabolic glycosyltransferases. The mechanism by which GlcCer is flipped remains unclear. To investigate the role of GlcCer-binding partners in this process, we previously made cleavable, biotinylated, photoreactive GlcCer analogs in which the reactive nitrene was closely apposed to the GlcCer head group, while maintaining a C16-acyl chain. GlcCer-binding protein specificity was validated for both photoprobes. Using one probe, XLB, here we identified ATP-binding cassette (ABC) transporters ABCA3, ABCB4, and ABCB10 as unfractionated microsomal GlcCer-binding proteins in DU-145 prostate tumor cells. siRNA knockdown (KD) of these transporters differentially blocked GSL synthesis assessed in toto and via metabolic labeling. KD of ABCA3 reduced acid/neutral GSL levels, but increased those of LacCer, while KD of ABCB4 preferentially reduced neutral GSL levels, and KD of ABCB10 reduced levels of both neutral and acidic GSLs. Depletion of ABCA12, implicated in GlcCer transport, preferentially decreased neutral GSL levels, while ABCB1 KD preferentially reduced gangliosides, but increased neutral GSL Gb3. These results imply that multiple ABC transporters may provide distinct but overlapping GlcCer and LacCer pools within the Golgi lumen for anabolism of different GSL series by metabolic channeling. Differential ABC family member usage may fine-tune GSL biosynthesis depending on cell/tissue type. We conclude that ABC transporters provide a new tool for the regulation of GSL biosynthesis and serve as potential targets to reduce selected GSL species/subsets in diseases in which GSLs are dysregulated.
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Affiliation(s)
- Monique Budani
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Christiane Auray-Blais
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Québec, Canada
| | - Clifford Lingwood
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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12
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Structures of ABCB4 provide insight into phosphatidylcholine translocation. Proc Natl Acad Sci U S A 2021; 118:2106702118. [PMID: 34385322 DOI: 10.1073/pnas.2106702118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
ABCB4 is expressed in hepatocytes and translocates phosphatidylcholine into bile canaliculi. The mechanism of specific lipid recruitment from the canalicular membrane, which is essential to mitigate the cytotoxicity of bile salts, is poorly understood. We present cryogenic electron microscopy structures of human ABCB4 in three distinct functional conformations. An apo-inward structure reveals how phospholipid can be recruited from the inner leaflet of the membrane without flipping its orientation. An occluded structure reveals a single phospholipid molecule in a central cavity. Its choline moiety is stabilized by cation-π interactions with an essential tryptophan residue, rationalizing the specificity of ABCB4 for phosphatidylcholine. In an inhibitor-bound structure, a posaconazole molecule blocks phospholipids from reaching the central cavity. Using a proteoliposome-based translocation assay with fluorescently labeled phosphatidylcholine analogs, we recapitulated the substrate specificity of ABCB4 in vitro and confirmed the role of the key tryptophan residue. Our results provide a structural basis for understanding an essential translocation step in the generation of bile and its sensitivity to azole drugs.
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13
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Shukla S, Baumgart T. Enzymatic trans-bilayer lipid transport: Mechanisms, efficiencies, slippage, and membrane curvature. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183534. [PMID: 33340491 PMCID: PMC8351443 DOI: 10.1016/j.bbamem.2020.183534] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 12/12/2022]
Abstract
The eukaryotic plasma membrane's lipid composition is found to be ubiquitously asymmetric comparing inner and outer leaflets. This membrane lipid asymmetry plays a crucial role in diverse cellular processes critical for cell survival. A specialized set of transmembrane proteins called translocases, or flippases, have evolved to maintain this membrane lipid asymmetry in an energy-dependent manner. One potential consequence of local variations in membrane lipid asymmetry is membrane remodeling, which is essential for cellular processes such as intracellular trafficking. Recently, there has been a surge in the identification and characterization of flippases, which has significantly advanced the understanding of their functional mechanisms. Furthermore, there are intriguing possibilities for a coupling between membrane curvature and flippase activity. In this review we highlight studies that link membrane shape and remodeling to differential stresses generated by the activity of lipid flippases with an emphasis on data obtained through model membrane systems. We review the common mechanistic models of flippase-mediated lipid flipping and discuss common techniques used to test lipid flippase activity. We then compare the existing data on lipid translocation rates by flippases and conclude with potential future directions for this field.
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Affiliation(s)
- Sankalp Shukla
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Tobias Baumgart
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, United States.
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14
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Jain BK, Roland BP, Graham TR. Exofacial membrane composition and lipid metabolism regulates plasma membrane P4-ATPase substrate specificity. J Biol Chem 2020; 295:17997-18009. [PMID: 33060204 PMCID: PMC7939387 DOI: 10.1074/jbc.ra120.014794] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/22/2020] [Indexed: 01/21/2023] Open
Abstract
The plasma membrane of a cell is characterized by an asymmetric distribution of lipid species across the exofacial and cytofacial aspects of the bilayer. Regulation of membrane asymmetry is a fundamental characteristic of membrane biology and is crucial for signal transduction, vesicle transport, and cell division. The type IV family of P-ATPases, or P4-ATPases, establishes membrane asymmetry by selection and transfer of a subset of membrane lipids from the lumenal or exofacial leaflet to the cytofacial aspect of the bilayer. It is unclear how P4-ATPases sort through the spectrum of membrane lipids to identify their desired substrate(s) and how the membrane environment modulates this activity. Therefore, we tested how the yeast plasma membrane P4-ATPase, Dnf2, responds to changes in membrane composition induced by perturbation of endogenous lipid biosynthetic pathways or exogenous application of lipid. The primary substrates of Dnf2 are glucosylceramide (GlcCer) and phosphatidylcholine (PC, or their lyso-lipid derivatives), and we find that these substrates compete with each other for transport. Acutely inhibiting sphingolipid synthesis using myriocin attenuates transport of exogenously applied GlcCer without perturbing PC transport. Deletion of genes controlling later steps of glycosphingolipid production also perturb GlcCer transport to a greater extent than PC transport. In contrast, perturbation of ergosterol biosynthesis reduces PC and GlcCer transport equivalently. Surprisingly, application of lipids that are poor transport substrates differentially affects PC and GlcCer transport by Dnf2, thus altering substrate preference. Our data indicate that Dnf2 exhibits exquisite sensitivity to the membrane composition, thus providing feedback onto the function of the P4-ATPases.
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Affiliation(s)
- Bhawik Kumar Jain
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Bartholomew P Roland
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
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15
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Salustiano EJ, da Costa KM, Freire-de-Lima L, Mendonça-Previato L, Previato JO. Inhibition of glycosphingolipid biosynthesis reverts multidrug resistance by differentially modulating ABC transporters in chronic myeloid leukemias. J Biol Chem 2020; 295:6457-6471. [PMID: 32229586 DOI: 10.1074/jbc.ra120.013090] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/27/2020] [Indexed: 12/16/2022] Open
Abstract
Multidrug resistance (MDR) in cancer arises from cross-resistance to structurally- and functionally-divergent chemotherapeutic drugs. In particular, MDR is characterized by increased expression and activity of ATP-binding cassette (ABC) superfamily transporters. Sphingolipids are substrates of ABC proteins in cell signaling, membrane biosynthesis, and inflammation, for example, and their products can favor cancer progression. Glucosylceramide (GlcCer) is a ubiquitous glycosphingolipid (GSL) generated by glucosylceramide synthase, a key regulatory enzyme encoded by the UDP-glucose ceramide glucosyltransferase (UGCG) gene. Stressed cells increase de novo biosynthesis of ceramides, which return to sub-toxic levels after UGCG mediates incorporation into GlcCer. Given that cancer cells seem to mobilize UGCG and have increased GSL content for ceramide clearance, which ultimately contributes to chemotherapy failure, here we investigated how inhibition of GSL biosynthesis affects the MDR phenotype of chronic myeloid leukemias. We found that MDR is associated with higher UGCG expression and with a complex GSL profile. UGCG inhibition with the ceramide analog d-threo-1-(3,4,-ethylenedioxy)phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (EtDO-P4) greatly reduced GSL and monosialotetrahexosylganglioside levels, and co-treatment with standard chemotherapeutics sensitized cells to mitochondrial membrane potential loss and apoptosis. ABC subfamily B member 1 (ABCB1) expression was reduced, and ABCC-mediated efflux activity was modulated by competition with nonglycosylated ceramides. Consistently, inhibition of ABCC-mediated transport reduced the efflux of exogenous C6-ceramide. Overall, UGCG inhibition impaired the malignant glycophenotype of MDR leukemias, which typically overcomes drug resistance through distinct mechanisms. This work sheds light on the involvement of GSL in chemotherapy failure, and its findings suggest that targeted GSL modulation could help manage MDR leukemias.
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Affiliation(s)
- Eduardo J Salustiano
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho - Centro de Ciências da Saúde C1-042, Universidade Federal do Rio de Janeiro; Av. Carlos Chagas Filho 373 - Cidade Universitária, CEP 21941-902, Rio de Janeiro/RJ, Brazil
| | - Kelli M da Costa
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho - Centro de Ciências da Saúde C1-042, Universidade Federal do Rio de Janeiro; Av. Carlos Chagas Filho 373 - Cidade Universitária, CEP 21941-902, Rio de Janeiro/RJ, Brazil
| | - Leonardo Freire-de-Lima
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho - Centro de Ciências da Saúde C1-042, Universidade Federal do Rio de Janeiro; Av. Carlos Chagas Filho 373 - Cidade Universitária, CEP 21941-902, Rio de Janeiro/RJ, Brazil
| | - Lucia Mendonça-Previato
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho - Centro de Ciências da Saúde C1-042, Universidade Federal do Rio de Janeiro; Av. Carlos Chagas Filho 373 - Cidade Universitária, CEP 21941-902, Rio de Janeiro/RJ, Brazil
| | - José O Previato
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho - Centro de Ciências da Saúde C1-042, Universidade Federal do Rio de Janeiro; Av. Carlos Chagas Filho 373 - Cidade Universitária, CEP 21941-902, Rio de Janeiro/RJ, Brazil
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16
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Muller MP, Jiang T, Sun C, Lihan M, Pant S, Mahinthichaichan P, Trifan A, Tajkhorshid E. Characterization of Lipid-Protein Interactions and Lipid-Mediated Modulation of Membrane Protein Function through Molecular Simulation. Chem Rev 2019; 119:6086-6161. [PMID: 30978005 PMCID: PMC6506392 DOI: 10.1021/acs.chemrev.8b00608] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The cellular membrane constitutes one of the most fundamental compartments of a living cell, where key processes such as selective transport of material and exchange of information between the cell and its environment are mediated by proteins that are closely associated with the membrane. The heterogeneity of lipid composition of biological membranes and the effect of lipid molecules on the structure, dynamics, and function of membrane proteins are now widely recognized. Characterization of these functionally important lipid-protein interactions with experimental techniques is however still prohibitively challenging. Molecular dynamics (MD) simulations offer a powerful complementary approach with sufficient temporal and spatial resolutions to gain atomic-level structural information and energetics on lipid-protein interactions. In this review, we aim to provide a broad survey of MD simulations focusing on exploring lipid-protein interactions and characterizing lipid-modulated protein structure and dynamics that have been successful in providing novel insight into the mechanism of membrane protein function.
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Affiliation(s)
- Melanie P. Muller
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Tao Jiang
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Chang Sun
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Muyun Lihan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Paween Mahinthichaichan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Anda Trifan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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17
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Tan SF, Dunton W, Liu X, Fox TE, Morad SAF, Desai D, Doi K, Conaway MR, Amin S, Claxton DF, Wang HG, Kester M, Cabot MC, Feith DJ, Loughran TP. Acid ceramidase promotes drug resistance in acute myeloid leukemia through NF-κB-dependent P-glycoprotein upregulation. J Lipid Res 2019; 60:1078-1086. [PMID: 30962310 DOI: 10.1194/jlr.m091876] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/02/2019] [Indexed: 12/22/2022] Open
Abstract
Acute myeloid leukemia (AML) is the most common acute leukemia in adults. More than half of older AML patients fail to respond to cytotoxic chemotherapy, and most responders relapse with drug-resistant disease. Failure to achieve complete remission can be partly attributed to the drug resistance advantage of AML blasts that frequently express P-glycoprotein (P-gp), an ATP-binding cassette transporter. Our previous work showed that elevated acid ceramidase (AC) levels in AML contribute to blast survival. Here, we investigated P-gp expression levels in AML relative to AC. Using parental HL-60 cells and drug-resistant derivatives as our model, we found that P-gp expression and efflux activity were highly upregulated in resistant derivatives. AC overexpression in HL-60 conferred resistance to the AML chemotherapeutic drugs, cytarabine, mitoxantrone, and daunorubicin, and was linked to P-gp upregulation. Furthermore, targeting AC through pharmacologic or genetic approaches decreased P-gp levels and increased sensitivity to chemotherapeutic drugs. Mechanistically, AC overexpression increased NF-κB activation whereas NF-kB inhibitors reduced P-gp levels, indicating that the NF-kappaB pathway contributes to AC-mediated modulation of P-gp expression. Hence, our data support an important role for AC in drug resistance as well as survival and suggest that sphingolipid targeting approaches may also impact drug resistance in AML.
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Affiliation(s)
- Su-Fern Tan
- Department of Medicine, Division of Hematology and Oncology University of Virginia School of Medicine, Charlottesville, VA
| | - Wendy Dunton
- Department of Medicine, Division of Hematology and Oncology University of Virginia School of Medicine, Charlottesville, VA
| | - Xin Liu
- Penn State Hershey Cancer Institute Hershey, PA
| | - Todd E Fox
- Departments of Pharmacology University of Virginia School of Medicine, Charlottesville, VA
| | - Samy A F Morad
- Department of Pharmacology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt.,Department of Biochemistry and Molecular Biology Brody School of Medicine, East Carolina University, Greenville, NC
| | - Dhimant Desai
- Departments of Pharmacology Pennsylvania State University College of Medicine, Hershey, PA
| | - Kenichiro Doi
- Pediatrics Pennsylvania State University College of Medicine, Hershey, PA
| | - Mark R Conaway
- Public Health Sciences University of Virginia School of Medicine, Charlottesville, VA
| | - Shantu Amin
- Departments of Pharmacology Pennsylvania State University College of Medicine, Hershey, PA
| | | | - Hong-Gang Wang
- Pediatrics Pennsylvania State University College of Medicine, Hershey, PA
| | - Mark Kester
- Departments of Pharmacology University of Virginia School of Medicine, Charlottesville, VA.,University of Virginia Cancer Center Charlottesville, VA
| | - Myles C Cabot
- Department of Biochemistry and Molecular Biology Brody School of Medicine, East Carolina University, Greenville, NC
| | - David J Feith
- Department of Medicine, Division of Hematology and Oncology University of Virginia School of Medicine, Charlottesville, VA.,University of Virginia Cancer Center Charlottesville, VA
| | - Thomas P Loughran
- Department of Medicine, Division of Hematology and Oncology University of Virginia School of Medicine, Charlottesville, VA .,University of Virginia Cancer Center Charlottesville, VA
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18
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Huang C, Tu Y, Freter CE. Fludarabine-resistance associates with ceramide metabolism and leukemia stem cell development in chronic lymphocytic leukemia. Oncotarget 2018; 9:33124-33137. [PMID: 30237856 PMCID: PMC6145702 DOI: 10.18632/oncotarget.26043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 08/13/2018] [Indexed: 01/13/2023] Open
Abstract
Fludarabine (flu) -containing regimens such as flu, cyclophosphamide and rituximab have been established as one of the standard first line therapy in medically-fit chronic lymphocytic leukemia (CLL) patients. Therefore, flu-refractory (primary flu-insensitivity or flu-caused relapse) remains a major problem causing treatment failure for CLL patients. We isolated the peripheral blood mononuclear cells (PBMCs) from CLL patients and treated with flu to find flu-refractory cases, and established flu-resistant clonal cells to study molecular mechanism of flu-resistance. By comparing parental MEC-2 cells, a human CLL cell line, we found that flu-resistant clonal cells were significantly increased lethal dose 50 of flu concentration, and up-regulated expression of P-glycoprotein, a drug-resistant marker, glucosylceramide synthase (GCS), an enzyme that can convert ceramide to glucosylceramide, and CD34, a leukemia stem cell marker. Overexpression of GCS leads to promptly elimination of cellular ceramide levels and accumulation of glucosylceramide, which reduces apoptosis and promotes survival and proliferation of flu-resistant clonal cells. Furthermore, we demonstrated that the accumulation of glucosylceramide can be blocked by PDMP to restore flu-sensitivity in flu-resistant clonal cells. We also found that elevating glucosylceramide levels in flu-resistant clonal cells was associated with up-regulation of GCS and CD34 expression. Importantly, overexpression of GCS or CD34 was also determined in flu-refractory PBMCs. Our results show that flu-resistance is associated with the alteration of ceramide metabolism and the development of leukemia stem cell-like cells. The flu-resistance can be reversed by GCS inhibition as a novel strategy for overcoming drug resistance.
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Affiliation(s)
- Chunfa Huang
- Division of Hematology/Oncology, Department of Internal Medicine, School of Medicine, Saint Louis University, Saint Louis, MO, 63110, USA
| | - Yifan Tu
- Division of Hematology/Oncology, Department of Internal Medicine, School of Medicine, Saint Louis University, Saint Louis, MO, 63110, USA
| | - Carl E Freter
- Division of Hematology/Oncology, Department of Internal Medicine, School of Medicine, Saint Louis University, Saint Louis, MO, 63110, USA
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19
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Abstract
Gangliosides are sialic acid containing glycosphingolipids, which are abundant in mammalian brain tissue. Several fatal human diseases are caused by defects in glycolipid metabolism. Defects in their degradation lead to an accumulation of metabolites upstream of the defective reactions, whereas defects in their biosynthesis lead to diverse problems in a large number of organs.Gangliosides are primarily positioned with their ceramide anchor in the neuronal plasma membrane and the glycan head group exposed on the cell surface. Their biosynthesis starts in the endoplasmic reticulum with the formation of the ceramide anchor, followed by sequential glycosylation reactions, mainly at the luminal surface of Golgi and TGN membranes, a combinatorial process, which is catalyzed by often promiscuous membrane-bound glycosyltransferases.Thereafter, the gangliosides are transported to the plasma membrane by exocytotic membrane flow. After endocytosis, they are degraded within the endolysosomal compartments by a complex machinery of degrading enzymes, lipid-binding activator proteins, and negatively charged lipids.
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Affiliation(s)
- Bernadette Breiden
- LIMES Institute, Membrane Biology & Lipid Biochemistry Unit, Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Bonn, Germany
| | - Konrad Sandhoff
- LIMES Institute, Membrane Biology & Lipid Biochemistry Unit, Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Bonn, Germany.
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20
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Lee WK, Kolesnick RN. Sphingolipid abnormalities in cancer multidrug resistance: Chicken or egg? Cell Signal 2017; 38:134-145. [PMID: 28687494 DOI: 10.1016/j.cellsig.2017.06.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 06/25/2017] [Accepted: 06/25/2017] [Indexed: 12/12/2022]
Abstract
The cancer multidrug resistance (MDR) phenotype encompasses a myriad of molecular, genetic and cellular alterations resulting from progressive oncogenic transformation and selection. Drug efflux transporters, in particular the MDR P-glycoprotein ABCB1, play an important role in MDR but cannot confer the complete phenotype alone indicating parallel alterations are prerequisite. Sphingolipids are essential constituents of lipid raft domains and directly participate in functionalization of transmembrane proteins, including providing an optimal lipid microenvironment for multidrug transporters, and are also perturbed in cancer. Here we postulate that increased sphingomyelin content, developing early in some cancers, recruits and functionalizes plasma membrane ABCB1 conferring a state of partial MDR, which is completed by glycosphingolipid disturbance and the appearance of intracellular vesicular ABCB1. In this review, the independent and interdependent roles of sphingolipid alterations and ABCB1 upregulation during the transformation process and resultant conferment of partial and complete MDR phenotypes are discussed.
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Affiliation(s)
- Wing-Kee Lee
- Laboratory of Signal Transduction, Sloan Kettering Institute for Cancer Research, Memorial Sloan-Kettering Cancer Center, New York, United States; Institute for Physiology, Pathophysiology and Toxicology, Centre for Biomedical Education and Research (ZBAF), Witten/Herdecke University, Witten, Germany.
| | - Richard N Kolesnick
- Laboratory of Signal Transduction, Sloan Kettering Institute for Cancer Research, Memorial Sloan-Kettering Cancer Center, New York, United States
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21
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Abdul-Hammed M, Breiden B, Schwarzmann G, Sandhoff K. Lipids regulate the hydrolysis of membrane bound glucosylceramide by lysosomal β-glucocerebrosidase. J Lipid Res 2017; 58:563-577. [PMID: 28126847 DOI: 10.1194/jlr.m073510] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/24/2017] [Indexed: 01/24/2023] Open
Abstract
Glucosylceramide (GlcCer) is the primary storage lipid in the lysosomes of Gaucher patients and a secondary one in Niemann-Pick disease types A, B, and C. The regulatory roles of lipids on the hydrolysis of membrane bound GlcCer by lysosomal β-glucocerebrosidase (GBA1) was probed using a detergent-free liposomal assay. The degradation rarely occurs at uncharged liposomal surfaces in the absence of saposin (Sap) C. However, anionic lipids stimulate GlcCer hydrolysis at low pH by up to 1,000-fold depending on the nature and position of the negative charges in their head groups while cationic lipids inhibit the degradation, thus showing the importance of electrostatic interactions between the polycationic GBA1 and the negatively charged vesicle surfaces at low pH. Ceramide, fatty acids, monoacylglycerol, and diacylglycerol also stimulate GlcCer hydrolysis while SM, sphingosine, and sphinganine play strong inhibitory roles, thereby explaining the secondary storage of GlcCer in Niemann-Pick diseases. Surprisingly, cholesterol stimulates GlcCer degradation in the presence of bis(monoacylglycero)phosphate (BMP). Sap C strongly stimulates GlcCer hydrolysis even in the absence of BMP and the regulatory roles of the intraendolysosomal lipids on its activity is discussed. Our data suggest that these strong modifiers of GlcCer hydrolysis affect the genotype-phenotype correlation in several cases of Gaucher patients independent of the types.
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Affiliation(s)
- Misbaudeen Abdul-Hammed
- Life and Medical Sciences (LIMES) Institut, Membrane Biology and Lipid Biochemistry Unit, Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Bonn, Germany.,Biophysical Chemistry Group, Department of Pure and Applied Chemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Bernadette Breiden
- Life and Medical Sciences (LIMES) Institut, Membrane Biology and Lipid Biochemistry Unit, Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Bonn, Germany
| | - Günter Schwarzmann
- Life and Medical Sciences (LIMES) Institut, Membrane Biology and Lipid Biochemistry Unit, Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Bonn, Germany
| | - Konrad Sandhoff
- Life and Medical Sciences (LIMES) Institut, Membrane Biology and Lipid Biochemistry Unit, Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Bonn, Germany
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22
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Glycosphingolipid storage in Fabry mice extends beyond globotriaosylceramide and is affected by ABCB1 depletion. Future Sci OA 2016; 2:FSO147. [PMID: 28116130 PMCID: PMC5242178 DOI: 10.4155/fsoa-2016-0027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 08/10/2016] [Indexed: 11/17/2022] Open
Abstract
Aim: Fabry disease is caused by α-galactosidase A deficiency leading to accumulation of globotriaosylceramide (Gb3) in tissues. Clinical manifestations do not appear to correlate with total Gb3 levels. Studies examining tissue distribution of specific acyl chain species of Gb3 and upstream glycosphingolipids are lacking. Material & methods/Results: Thorough characterization of the Fabry mouse sphingolipid profile by LC-MS revealed unique Gb3 acyl chain storage profiles. Storage extended beyond Gb3; all Fabry tissues also accumulated monohexosylceramides. Depletion of ABCB1 had a complex effect on glycosphingolipid storage. Conclusion: These data provide insights into how specific sphingolipid species correlate with one another and how these correlations change in the α-galactosidase A-deficient state, potentially leading to the identification of more specific biomarkers of Fabry disease. Fabry disease is caused by a shortage of the enzyme α-galactosidase A leading to storage of a fat called globotriaosylceramide (Gb3) in tissues. Disease severity does not appear to correlate directly with total Gb3. Importantly, Gb3 is comprised of many highly related but distinct species. We examined levels of Gb3 species and precursor molecules in Fabry mice. Gb3 species and storage are unique to each tissue. Furthermore, storage is not limited to Gb3; precursor fats are also elevated. Detailed analyses of differences in storage between the normal and α-galactosidase A-deficient state may provide a better understanding of the causes of Fabry disease.
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23
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Assay of Flippase Activity in Proteoliposomes Using Fluorescent Lipid Derivatives. Methods Mol Biol 2016; 1377:181-91. [PMID: 26695033 DOI: 10.1007/978-1-4939-3179-8_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Specific membrane proteins, termed lipid flippases, play a central role in facilitating the movement of lipids across cellular membranes. In this protocol, we describe the reconstitution of ATP-driven lipid flippases in liposomes and the analysis of their in vitro flippase activity based on the use of fluorescent lipid derivatives. Working with purified and reconstituted systems provides a well-defined experimental setup and allows to directly characterize these membrane proteins at the molecular level.
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24
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Abstract
Scramblases translocate phospholipids across the membrane bilayer bidirectionally in an ATP-independent manner. The first scramblase to be identified and biochemically verified was opsin, the apoprotein of the photoreceptor rhodopsin. Rhodopsin is a G protein-coupled receptor localized in rod photoreceptor disc membranes of the retina where it is responsible for the perception of light. Rhodopsin's scramblase activity does not depend on its ligand 11-cis-retinal, i.e., the apoprotein opsin is also active as a scramblase. Although constitutive and regulated phospholipid scrambling play an important role in cell physiology, only a few phospholipid scramblases have been identified so far besides opsin. Here we describe a fluorescence-based assay of opsin's scramblase activity. Opsin is reconstituted into large unilamellar liposomes composed of phosphatidylcholine, phosphatidylglycerol and a trace quantity of fluorescent NBD-labeled PC (1-palmitoyl-2-{6-[7-nitro-2-1,3-benzoxadiazole-4-yl)amino]hexanoyl}-sn-glycero-3-phosphocholine). Scramblase activity is determined by measuring the extent to which NBD-PC molecules located in the inner leaflet of the vesicle are able to access the outer leaflet where their fluorescence is chemically eliminated by a reducing agent that cannot cross the membrane. The methods we describe have general applicability and can be used to identify and characterize scramblase activities of other membrane proteins.
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Affiliation(s)
- Birgit Ploier
- Department of Biochemistry, Weill Cornell Medical College
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College;
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25
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Chung FS, Santiago JS, Jesus MFMD, Trinidad CV, See MFE. Disrupting P-glycoprotein function in clinical settings: what can we learn from the fundamental aspects of this transporter? Am J Cancer Res 2016; 6:1583-1598. [PMID: 27648351 PMCID: PMC5004065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 05/01/2016] [Indexed: 06/06/2023] Open
Abstract
P-glycoprotein is one of the most well-studied drug transporters, significant for its role in cancer multiple drug resistance. However, using P-gp inhibitors with the aim of enhancing the therapeutic efficacy of anti-cancer drugs has led to disappointing outcomes. Furthermore, several lead compounds suggested by in vitro and pre-clinical studies have shown variable pharmacokinetics and therapeutic efficacies when applied in the clinical setting. This review will highlight the need to revisit a sound approach to better design and apply P-gp inhibitors in light of safety and efficacy. Challenges confronting the issue hinge upon myriad studies that do not necessarily represent the heterogeneous target population of this therapeutic approach. The application of P-gp modulators has also been complicated by the promiscuous substrate-binding behaviour of P-gp, as well as toxicities related to its intrinsic presence in healthy tissue. This review capitalizes on information spanning genetics, energetics, and pharmacology, bringing to light some fundamental aspects that ought to be reconsidered in order to improve upon and design the next generation of P-gp inhibitors.
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Affiliation(s)
- Francisco S Chung
- Cellular Therapeutics Center, Makati Medical Center Makati City, Philippines 1229
| | - Jayson S Santiago
- Cellular Therapeutics Center, Makati Medical Center Makati City, Philippines 1229
| | | | - Camille V Trinidad
- Cellular Therapeutics Center, Makati Medical Center Makati City, Philippines 1229
| | - Melvin Floyd E See
- Cellular Therapeutics Center, Makati Medical Center Makati City, Philippines 1229
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26
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Yeast ABC transporters in lipid trafficking. Fungal Genet Biol 2016; 93:25-34. [DOI: 10.1016/j.fgb.2016.05.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 05/28/2016] [Accepted: 05/31/2016] [Indexed: 12/31/2022]
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27
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Budani M, Mylvaganam M, Binnington B, Lingwood C. Synthesis of a novel photoactivatable glucosylceramide cross-linker. J Lipid Res 2016; 57:1728-36. [PMID: 27412675 DOI: 10.1194/jlr.d069609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Indexed: 01/08/2023] Open
Abstract
The biosynthesis of glucosylceramide (GlcCer) is a key rate-limiting step in complex glycosphingolipid (GSL) biosynthesis. To further define interacting partners of GlcCer, we have made a cleavable, biotinylated, photoreactive GlcCer analog in which the reactive nitrene is closely apposed to the GlcCer head group, by substituting the native fatty acid with d, l-2-aminohexadecanoic acid. Two amino-GlcCer diastereomer cross-linkers (XLA and XLB) were generated. XLB proved an effective lactosylceramide (LacCer) synthase substrate while XLA was inhibitory. Both probes specifically bound and cross-linked the GlcCer binding protein, glycolipid transfer protein (GLTP), but not other GSL binding proteins (Shiga toxin and cholera toxin). GlcCer inhibited GLTP cross-linking. Both GlcCer cross-linkers competed with microsomal nitrobenzoxadiazole (NBD)-GlcCer anabolism to NBD-LacCer. GLTP showed marked, ATP-dependent enhancement of cell-free intact microsomal LacCer synthesis from endogenous or exogenous liposomal GlcCer, supporting a role in the transport/membrane translocation of cytosolic and extra-Golgi GlcCer. GLTP was specifically labeled by either XLA or XLB GlcCer cross-linker during this process, together with a (the same) small subset of microsomal proteins. These cross-linkers will serve to probe physiologically relevant GlcCer-interacting cellular proteins.
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Affiliation(s)
- Monique Budani
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada Division of Molecular Structure and Function, Peter Gilgan Centre for Research and Learning, Research Institute, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Murugesapillai Mylvaganam
- Division of Molecular Structure and Function, Peter Gilgan Centre for Research and Learning, Research Institute, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Beth Binnington
- Division of Molecular Structure and Function, Peter Gilgan Centre for Research and Learning, Research Institute, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Clifford Lingwood
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada Division of Molecular Structure and Function, Peter Gilgan Centre for Research and Learning, Research Institute, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Multidrug resistant tumour cells shed more microvesicle-like EVs and less exosomes than their drug-sensitive counterpart cells. Biochim Biophys Acta Gen Subj 2016; 1860:618-27. [DOI: 10.1016/j.bbagen.2015.12.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/06/2015] [Accepted: 12/16/2015] [Indexed: 12/21/2022]
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Clay AT, Lu P, Sharom FJ. Interaction of the P-Glycoprotein Multidrug Transporter with Sterols. Biochemistry 2015; 54:6586-97. [DOI: 10.1021/acs.biochem.5b00904] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Adam T. Clay
- Department of Molecular and
Cellular Biology and Biophysics Interdepartmental Group, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Peihua Lu
- Department of Molecular and
Cellular Biology and Biophysics Interdepartmental Group, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Frances J. Sharom
- Department of Molecular and
Cellular Biology and Biophysics Interdepartmental Group, University of Guelph, Guelph, ON, Canada N1G 2W1
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30
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Schröter F, Jakop U, Teichmann A, Haralampiev I, Tannert A, Wiesner B, Müller P, Müller K. Lipid dynamics in boar sperm studied by advanced fluorescence imaging techniques. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 45:149-63. [DOI: 10.1007/s00249-015-1084-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/09/2015] [Accepted: 09/17/2015] [Indexed: 12/23/2022]
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Abstract
Multidrug-resistance (MDR) phenomena are a worldwide health concern. ATP-binding cassette efflux pumps as P-glycoprotein have been thoroughly studied in a frantic run to develop new efflux modulators capable to reverse MDR phenotypes. The study of efflux pumps has provided some key aspects on drug extrusion, however the answers could not be found solely on ATP-binding cassette transporters. Its counterpart – the plasma membrane – is now emerging as a critical structure able to modify drug behavior and efflux pump activity. Alterations in the membrane surrounding P-glycoprotein are now known to modulate drug efflux, with membrane-related biophysical, biochemical and mechanical aspects further increasing the complexity of an already multifaceted phenomena. This review summarizes the main knowledge comprising the plasma membrane role in MDR.
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Hegedüs C, Telbisz Á, Hegedűs T, Sarkadi B, Özvegy-Laczka C. Lipid regulation of the ABCB1 and ABCG2 multidrug transporters. Adv Cancer Res 2015; 125:97-137. [PMID: 25640268 DOI: 10.1016/bs.acr.2014.10.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This chapter deals with the interactions of two medically important multidrug ABC transporters (MDR-ABC), ABCB1 and ABCG2, with lipid molecules. Both ABCB1 and ABCG2 are capable of transporting a wide range of hydrophobic drugs and xenobiotics and are involved in cancer chemotherapy resistance. Therefore, the exploration of their mechanism of action has major therapeutic consequences. As discussed here in detail, both ABCB1 and ABCG2 are significantly affected by various lipid compounds especially those residing in their close proximity in the plasma membrane. ABCB1 is capable of transporting lipids and lipid derivatives, and thus may alter the general membrane composition by "flopping" membrane lipid constituents, while there is no such information regarding ABCG2. Still, both ABCB1 and ABCG2 show complex interactions with a variety of lipid molecules, and the transporters are significantly modulated by cholesterol and cholesterol derivatives at the posttranslational level. In this chapter, we explore the molecular details of the direct transporter-lipid interactions, the potential role of lipid-sensor domains within the proteins, as well as the application of experimental site-directed mutagenesis, detailed structural studies, and in silico modeling for examining these interactions. We also discuss the regulation of ABCB1 and ABCG2 expression at the transcriptional level, occurring through nuclear receptors involved in lipid sensing. The better understanding of lipid interactions with these medically important MDR-ABC transporters may significantly improve further drug development and clinical treatment options.
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Affiliation(s)
- Csilla Hegedüs
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Ágnes Telbisz
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tamás Hegedűs
- MTA-SE Molecular Biophysics Research Group of the Hungarian Academy of Sciences, Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Balázs Sarkadi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary; MTA-SE Molecular Biophysics Research Group of the Hungarian Academy of Sciences, Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Csilla Özvegy-Laczka
- MTA-SE Molecular Biophysics Research Group of the Hungarian Academy of Sciences, Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary.
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Yamaji T, Hanada K. Sphingolipid metabolism and interorganellar transport: localization of sphingolipid enzymes and lipid transfer proteins. Traffic 2014; 16:101-22. [PMID: 25382749 DOI: 10.1111/tra.12239] [Citation(s) in RCA: 289] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/29/2014] [Accepted: 11/06/2014] [Indexed: 11/28/2022]
Abstract
In recent decades, many sphingolipid enzymes, sphingolipid-metabolism regulators and sphingolipid transfer proteins have been isolated and characterized. This review will provide an overview of the intracellular localization and topology of sphingolipid enzymes in mammalian cells to highlight the locations where respective sphingolipid species are produced. Interestingly, three sphingolipids that reside or are synthesized in cytosolic leaflets of membranes (ceramide, glucosylceramide and ceramide-1-phosphate) all have cytosolic lipid transfer proteins (LTPs). These LTPs consist of ceramide transfer protein (CERT), four-phosphate adaptor protein 2 (FAPP2) and ceramide-1-phosphate transfer protein (CPTP), respectively. These LTPs execute functions that affect both the location and metabolism of the lipids they bind. Molecular details describing the mechanisms of regulation of LTPs continue to emerge and reveal a number of critical processes, including competing phosphorylation and dephosphorylation reactions and binding interactions with regulatory proteins and lipids that influence the transport, organelle distribution and metabolism of sphingolipids.
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Affiliation(s)
- Toshiyuki Yamaji
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
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Abdel Shakor AB, Atia M, Ismail IA, Alshehri A, El-Refaey H, Kwiatkowska K, Sobota A. Curcumin induces apoptosis of multidrug-resistant human leukemia HL60 cells by complex pathways leading to ceramide accumulation. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1672-82. [DOI: 10.1016/j.bbalip.2014.09.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 09/08/2014] [Accepted: 09/09/2014] [Indexed: 12/20/2022]
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Dimeloe S, Frick C, Fischer M, Gubser PM, Razik L, Bantug GR, Ravon M, Langenkamp A, Hess C. Human regulatory T cells lack the cyclophosphamide-extruding transporter ABCB1 and are more susceptible to cyclophosphamide-induced apoptosis. Eur J Immunol 2014; 121:343-56. [PMID: 25251877 DOI: 10.1093/toxsci/kfr071] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
ATP-binding cassette (ABC) transporters, including ABC-transporter B1 (ABCB1), extrude drugs, metabolites, and other compounds (such as mitotracker green (MTG)) from cells. Susceptibility of CD4(+) regulatory T (Treg) cells to the ABCB1-substrate cyclophosphamide (CPA) has been reported. Here, we characterized ABCB1 expression and function in human CD4(+) T-cell subsets. Naïve, central memory, and effector-memory CD4(+) T cells, but not Treg cells, effluxed MTG in an ABCB1-dependent manner. In line with this, ABCB1 mRNA and protein was expressed by nonregulatory CD4(+) T-cell subsets, but not Treg cells. In vitro, the ABCB1-substrate CPA was cytotoxic for Treg cells at a 100-fold lower dose than for nonregulatory counterparts, and, inversely, verapamil, an inhibitor of ABC transporters, increased CPA-toxicity in nonregulatory CD4(+) T cells but not Treg cells. Thus, Treg cells lack expression of ABCB1, rendering them selectively susceptible to CPA. Our findings provide mechanistic support for therapeutic strategies using CPA to boost anti-tumor immunity by selectively depleting Treg cells.
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Affiliation(s)
- Sarah Dimeloe
- Immunobiology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
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Ferreira RJ, Ferreira MJU, dos Santos DJVA. Reversing cancer multidrug resistance: insights into the efflux by ABC transports fromin silicostudies. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2014. [DOI: 10.1002/wcms.1196] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Ricardo J. Ferreira
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia; Universidade de Lisboa; Lisboa Portugal
| | - Maria-José U. Ferreira
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia; Universidade de Lisboa; Lisboa Portugal
| | - Daniel J. V. A. dos Santos
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia; Universidade de Lisboa; Lisboa Portugal
- REQUIMTE, Department of Chemistry & Biochemistry, Faculty of Sciences; University of Porto; Porto Portugal
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Structure and mechanism of ATP-dependent phospholipid transporters. Biochim Biophys Acta Gen Subj 2014; 1850:461-75. [PMID: 24746984 DOI: 10.1016/j.bbagen.2014.04.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 04/04/2014] [Accepted: 04/07/2014] [Indexed: 01/09/2023]
Abstract
BACKGROUND ATP-binding cassette (ABC) transporters and P4-ATPases are two large and seemingly unrelated families of primary active pumps involved in moving phospholipids from one leaflet of a biological membrane to the other. SCOPE OF REVIEW This review aims to identify common mechanistic features in the way phospholipid flipping is carried out by two evolutionarily unrelated families of transporters. MAJOR CONCLUSIONS Both protein families hydrolyze ATP, although they employ different mechanisms to use it, and have a comparable size with twelve transmembrane segments in the functional unit. Further, despite differences in overall architecture, both appear to operate by an alternating access mechanism and during transport they might allow access of phospholipids to the internal part of the transmembrane domain. The latter feature is obvious for ABC transporters, but phospholipids and other hydrophobic molecules have also been found embedded in P-type ATPase crystal structures. Taken together, in two diverse groups of pumps, nature appears to have evolved quite similar ways of flipping phospholipids. GENERAL SIGNIFICANCE Our understanding of the structural basis for phospholipid flipping is still limited but it seems plausible that a general mechanism for phospholipid flipping exists in nature. This article is part of a Special Issue entitled Structural biochemistry and biophysics of membrane proteins.
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Li W, Sharma M, Kaur P. The DrrAB efflux system of Streptomyces peucetius is a multidrug transporter of broad substrate specificity. J Biol Chem 2014; 289:12633-46. [PMID: 24634217 DOI: 10.1074/jbc.m113.536136] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The soil bacterium Streptomyces peucetius produces two widely used anticancer antibiotics, doxorubicin and daunorubicin. Present within the biosynthesis gene cluster in S. peucetius is the drrAB operon, which codes for a dedicated ABC (ATP binding cassette)-type transporter for the export of these two closely related antibiotics. Because of its dedicated nature, the DrrAB system is believed to belong to the category of single-drug transporters. However, whether it also contains specificity for other known substrates of multidrug transporters has never been tested. In this study we demonstrate under both in vivo and in vitro conditions that the DrrAB system can transport not only doxorubicin but is also able to export two most commonly studied MDR substrates, Hoechst 33342 and ethidium bromide. Moreover, we demonstrate that many other substrates (including verapamil, vinblastine, and rifampicin) of the well studied multidrug transporters inhibit DrrAB-mediated Dox transport with high efficiency, indicating that they are also substrates of the DrrAB pump. Kinetic studies show that inhibition of doxorubicin transport by Hoechst 33342 and rifampicin occurs by a competitive mechanism, whereas verapamil inhibits transport by a non-competitive mechanism, thus suggesting the possibility of more than one drug binding site in the DrrAB system. This is the first in-depth study of a drug resistance system from a producer organism, and it shows that a dedicated efflux system like DrrAB contains specificity for multiple drugs. The significance of these findings in evolution of poly-specificity in drug resistance systems is discussed.
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Affiliation(s)
- Wen Li
- From the Department of Biology, Georgia State University, Atlanta, Georgia 30303
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39
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Sharom FJ. Complex Interplay between the P-Glycoprotein Multidrug Efflux Pump and the Membrane: Its Role in Modulating Protein Function. Front Oncol 2014; 4:41. [PMID: 24624364 PMCID: PMC3939933 DOI: 10.3389/fonc.2014.00041] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 02/17/2014] [Indexed: 11/16/2022] Open
Abstract
Multidrug resistance in cancer is linked to expression of the P-glycoprotein multidrug transporter (Pgp, ABCB1), which exports many structurally diverse compounds from cells. Substrates first partition into the bilayer and then interact with a large flexible binding pocket within the transporter's transmembrane regions. Pgp has been described as a hydrophobic vacuum cleaner or an outwardly directed drug/lipid flippase. Recent X-ray crystal structures have shed some light on the nature of the drug-binding pocket and suggested routes by which substrates can enter it from the membrane. Detergents have profound effects on Pgp function, and several appear to be substrates. Biochemical and biophysical studies in vitro, some using purified reconstituted protein, have explored the effects of the membrane environment. They have demonstrated that Pgp is involved in a complex relationship with its lipid environment, which modulates the behavior of its substrates, as well as various functions of the protein, including ATP hydrolysis, drug binding, and drug transport. Membrane lipid composition and fluidity, phospholipid headgroup and acyl chain length all influence Pgp function. Recent studies focusing on thermodynamics and kinetics have revealed some important principles governing Pgp-lipid and substrate-lipid interactions, and how these affect drug-binding and transport. In some cells, Pgp is associated with cholesterol-rich microdomains, which may modulate its functions. The relationship between Pgp and cholesterol remains an open question; however, it clearly affects several aspects of its function in addition to substrate-membrane partitioning. The action of Pgp modulators appears to depend on their membrane permeability, and membrane fluidizers and surfactants reverse drug resistance, likely via an indirect mechanism. A detailed understanding of how the membrane affects Pgp substrates and Pgp's catalytic cycle may lead to new strategies to combat clinical drug resistance.
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Affiliation(s)
- Frances Jane Sharom
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
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Dahdouh F, Raane M, Thévenod F, Lee WK. Nickel-induced cell death and survival pathways in cultured renal proximal tubule cells: roles of reactive oxygen species, ceramide and ABCB1. Arch Toxicol 2014; 88:881-92. [DOI: 10.1007/s00204-014-1194-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 01/09/2014] [Indexed: 12/17/2022]
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Labeled chemical biology tools for investigating sphingolipid metabolism, trafficking and interaction with lipids and proteins. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:1161-73. [PMID: 24389251 DOI: 10.1016/j.bbalip.2013.12.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 12/10/2013] [Accepted: 12/17/2013] [Indexed: 12/17/2022]
Abstract
The unraveling of sphingolipid metabolism and function in the last 40 years relied on the extensive study of inherited human disease and specifically-tailored mouse models. However, only few of the achievements made so far would have been possible without chemical biology tools, such as fluorescent and/or radio-labeled and other artificial substrates, (mechanism-based) enzyme inhibitors, cross-linking probes or artificial membrane models. In this review we provide an overview over chemical biology tools that have been used to gain more insight into the molecular basis of sphingolipid-related biology. Many of these tools are still of high relevance for the investigation of current sphingolipid-related questions, others may stimulate the tailoring of novel probes suitable to address recent and future issues in the field. This article is part of a Special Issue entitled Tools to study lipid functions.
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42
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Leite JCDA, de Vasconcelos RB, da Silva SG, de Siqueira-Junior JP, Marques-Santos LF. ATP-binding cassette transporters protect sea urchin gametes and embryonic cells against the harmful effects of ultraviolet light. Mol Reprod Dev 2013; 81:66-83. [PMID: 24254332 DOI: 10.1002/mrd.22283] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 11/14/2013] [Indexed: 12/22/2022]
Abstract
Embryos of marine organisms whose development occurs externally are particularly sensitive to ultraviolet (UV) light (bands A and B, respectively, UVA and UVB). ATP-binding cassette (ABC) transporters are the first line of cellular defense against chemical or physical stress. The present work investigated the involvement of ABC transporters on UVA or UVB effects on eggs, spermatozoa, and embryonic cells of the sea urchin Echinometra lucunter. Gametes or embryos were exposed to UVA (3.6-14.4 kJ m(-2)) or UVB (0.112-14.4 kJ m(-2)), and embryonic development was monitored by optical microscopy at different developmental stages in the presence or absence of the ABC-transporter blockers reversin205 (ABCB1 blocker) or MK571 (ABCC1 blocker). E. lucunter eggs, spermatozoa and embryos were resistant to UVA exposure. Resistance to the harmful effects of UVB was strongly associated to ABC transporter activity (embryos > eggs > spermatozoa). ABCB1 or ABCC1 blockage promoted the injurious effects of UVA on spermatozoa. ABCC1 transporter blockage increased UVB-dependent damage in eggs while ABCB1 transporter inhibition increased harmful effects of UVB in embryonic cells. ABC-transporter activity was not, however, affected by UVB exposure. In conclusion, the present study is the first report on the protective role of ABC transporters against harmful effects of UVA and UVB on sea urchin eggs and embryonic cells.
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Affiliation(s)
- Jocelmo Cássio de Araujo Leite
- Departamento de Biologia Molecular, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil
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Schulze H, Sandhoff K. Sphingolipids and lysosomal pathologies. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:799-810. [PMID: 24184515 DOI: 10.1016/j.bbalip.2013.10.015] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 10/16/2013] [Accepted: 10/19/2013] [Indexed: 01/12/2023]
Abstract
Endocytosed (glyco)sphingolipids are degraded, together with other membrane lipids in a stepwise fashion by endolysosomal enzymes with the help of small lipid binding proteins, the sphingolipid activator proteins (SAPs), at the surface of intraluminal lysosomal vesicles. Inherited defects in a sphingolipid-degrading enzyme or SAP cause the accumulation of the corresponding lipid substrates, including cytotoxic lysosphingolipids, such as galactosylsphingosine and glucosylsphingosine, and lead to a sphingolipidosis. Analysis of patients with prosaposin deficiency revealed the accumulation of intra-endolysosmal vesicles and membrane structures (IM). Feeding of prosaposin reverses the storage, suggesting inner membrane structures as platforms of sphingolipid degradation. Water soluble enzymes can hardly attack sphingolipids embedded in the membrane of inner endolysosomal vesicles. The degradation of sphingolipids with few sugar residues therefore requires the help of the SAPs, and is strongly stimulated by anionic membrane lipids. IMs are rich in anionic bis(monoacylglycero)phosphate (BMP). This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology.
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Affiliation(s)
- Heike Schulze
- LIMES, Membrane Biology & Lipid Biochemistry Unit, c/o Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Str. 1, D-53115 Bonn, Germany
| | - Konrad Sandhoff
- LIMES, Membrane Biology & Lipid Biochemistry Unit, c/o Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Str. 1, D-53115 Bonn, Germany.
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Ferreira RJ, Ferreira MJU, dos Santos DJVA. Molecular Docking Characterizes Substrate-Binding Sites and Efflux Modulation Mechanisms within P-Glycoprotein. J Chem Inf Model 2013; 53:1747-60. [DOI: 10.1021/ci400195v] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Ricardo J. Ferreira
- Research Institute for Medicines
and Pharmaceutical Sciences (iMed.UL), Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-003
Lisbon, Portugal
| | - Maria-José U. Ferreira
- Research Institute for Medicines
and Pharmaceutical Sciences (iMed.UL), Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-003
Lisbon, Portugal
| | - Daniel J. V. A. dos Santos
- Research Institute for Medicines
and Pharmaceutical Sciences (iMed.UL), Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-003
Lisbon, Portugal
- REQUIMTE, Department of Chemistry & Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
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Nakamura H, Moriyama Y, Makiyama T, Emori S, Yamashita H, Yamazaki R, Murayama T. Lactosylceramide interacts with and activates cytosolic phospholipase A2α. J Biol Chem 2013; 288:23264-72. [PMID: 23801329 DOI: 10.1074/jbc.m113.491431] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lactosylceramide (LacCer) is a member of the glycosphingolipid family and is known to be a bioactive lipid in various cell physiological processes. However, the direct targets of LacCer and cellular events mediated by LacCer are largely unknown. In this study, we examined the effect of LacCer on the release of arachidonic acid (AA) and the activity of cytosolic phospholipase A2α (cPLA2α). In CHO-W11A cells, treatment with 1-phenyl-2-palmitoylamino-3-morpholino-1-propanol (PPMP), an inhibitor of glucosylceramide synthase, reduced the glycosphingolipid level, and the release of AA induced by A23187 or platelet-activating factor was inhibited. The addition of LacCer reversed the PPMP effect on the stimulus-induced AA release. Exogenous LacCer stimulated the release of AA, which was decreased by treatment with an inhibitor of cPLA2α or silencing of the enzyme. Treatment of CHO-W11A cells with LacCer induced the translocation of full-length cPLA2α and its C2 domain from the cytosol to the Golgi apparatus. LacCer also induced the translocation of the D43N mutant of cPLA2α. Treatment of L929 cells with TNF-α induced LacCer generation and mediated the translocation of cPLA2α and AA release, which was attenuated by treatment with PPMP. In vitro studies were then conducted to test whether LacCer interacts directly with cPLA2α. Phosphatidylcholine vesicles containing LacCer increased cPLA2α activity. LacCer bound to cPLA2α and its C2 domain in a Ca(2+)-independent manner. Thus, we propose that LacCer is a direct activator of cPLA2α.
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Affiliation(s)
- Hiroyuki Nakamura
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Chuo-ku, Chiba 260-8675, Japan.
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Liu YY, Hill RA, Li YT. Ceramide glycosylation catalyzed by glucosylceramide synthase and cancer drug resistance. Adv Cancer Res 2013; 117:59-89. [PMID: 23290777 DOI: 10.1016/b978-0-12-394274-6.00003-0] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Glucosylceramide synthase (GCS), converting ceramide to glucosylceramide, catalyzes the first reaction of ceramide glycosylation in sphingolipid metabolism. This glycosylation by GCS is a critical step regulating the modulation of cellular activities by controlling ceramide and glycosphingolipids (GSLs). An increase of ceramide in response to stresses, such as chemotherapy, drives cells to proliferation arrest and apoptosis or autophagy; however, ceramide glycosylation promptly eliminates ceramide and consequently, these induced processes, thus protecting cancer cells. Further, persistently enhanced ceramide glycosylation can increase GSLs, participating in selecting cancer cells to drug resistance. GCS is overexpressed in diverse drug-resistant cancer cells and in tumors of breast, colon, and leukemia that display poor response to chemotherapy. As ceramide glycosylation by GCS is a rate-limiting step in GSL synthesis, inhibition of GCS sensitizes cancer cells to anticancer drugs and eradicates cancer stem cells. Mechanistic studies indicate that uncoupling ceramide glycosylation can modulate gene expression, decreasing MDR1 through the cSrc/β-catenin pathway and restoring p53 expression via RNA splicing. These studies not only expand our knowledge in understanding how ceramide glycosylation affects cancer cells but also provide novel therapeutic approaches for targeting refractory tumors.
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Affiliation(s)
- Yong-Yu Liu
- Department of Basic Pharmaceutical Sciences, University of Louisiana at Monroe, Monroe, LA, USA.
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Marcoux J, Wang SC, Politis A, Reading E, Ma J, Biggin PC, Zhou M, Tao H, Zhang Q, Chang G, Morgner N, Robinson CV. Mass spectrometry reveals synergistic effects of nucleotides, lipids, and drugs binding to a multidrug resistance efflux pump. Proc Natl Acad Sci U S A 2013; 110:9704-9. [PMID: 23690617 PMCID: PMC3683783 DOI: 10.1073/pnas.1303888110] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Multidrug resistance is a serious barrier to successful treatment of many human diseases, including cancer, wherein chemotherapeutics are exported from target cells by membrane-embedded pumps. The most prevalent of these pumps, the ATP-Binding Cassette transporter P-glycoprotein (P-gp), consists of two homologous halves each comprising one nucleotide-binding domain and six transmembrane helices. The transmembrane region encapsulates a hydrophobic cavity, accessed by portals in the membrane, that binds cytotoxic compounds as well as lipids and peptides. Here we use mass spectrometry (MS) to probe the intact P-gp small molecule-bound complex in a detergent micelle. Activation in the gas phase leads to formation of ions, largely devoid of detergent, yet retaining drug molecules as well as charged or zwitterionic lipids. Measuring the rates of lipid binding and calculating apparent KD values shows that up to six negatively charged diacylglycerides bind more favorably than zwitterionic lipids. Similar experiments confirm binding of cardiolipins and show that prior binding of the immunosuppressant and antifungal antibiotic cyclosporin A enhances subsequent binding of cardiolipin. Ion mobility MS reveals that P-gp exists in an equilibrium between different states, readily interconverted by ligand binding. Overall these MS results show how concerted small molecule binding leads to synergistic effects on binding affinities and conformations of a multidrug efflux pump.
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Affiliation(s)
| | | | | | | | - Jerome Ma
- Biochemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Philip C. Biggin
- Biochemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | | | - Houchao Tao
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037; and
| | - Qinghai Zhang
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037; and
| | - Geoffrey Chang
- Skaggs School of Pharmacy and Pharmaceutical Sciences and Department of Pharmacology, School of Medicine, University of California at San Diego, La Jolla, CA 92093
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Wen PC, Verhalen B, Wilkens S, Mchaourab HS, Tajkhorshid E. On the origin of large flexibility of P-glycoprotein in the inward-facing state. J Biol Chem 2013; 288:19211-20. [PMID: 23658020 PMCID: PMC3696692 DOI: 10.1074/jbc.m113.450114] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
P-glycoprotein (Pgp) is one of the most biomedically relevant transporters in the ATP binding
cassette (ABC) superfamily due to its involvement in developing multidrug resistance in cancer
cells. Employing molecular dynamics simulations and double electron-electron resonance spectroscopy,
we have investigated the structural dynamics of membrane-bound Pgp in the inward-facing state and
found that Pgp adopts an unexpectedly wide range of conformations, highlighted by the degree of
separation between the two nucleotide-binding domains (NBDs). The distance between the two NBDs in
the equilibrium simulations covers a range of at least 20 Å, including, both, more open and
more closed NBD configurations than the crystal structure. The double electron-electron resonance
measurements on spin-labeled Pgp mutants also show wide distributions covering both longer and
shorter distances than those observed in the crystal structure. Based on structural and sequence
analyses, we propose that the transmembrane domains of Pgp might be more flexible than other
structurally known ABC exporters. The structural flexibility of Pgp demonstrated here is not only in
close agreement with, but also helps rationalize, the reported high NBD fluctuations in several ABC
exporters and possibly represents a fundamental difference in the transport mechanism between ABC
exporters and ABC importers. In addition, during the simulations we have captured partial entrance
of a lipid molecule from the bilayer into the lumen of Pgp, reaching the putative drug binding site.
The location of the protruding lipid suggests a putative pathway for direct drug recruitment from
the membrane.
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Affiliation(s)
- Po-Chao Wen
- Center for Biophysics and Computational Biology, Department of Biochemistry, College of Medicine, and The Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illnois 61801, USA
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Effects of the lipid environment, cholesterol and bile acids on the function of the purified and reconstituted human ABCG2 protein. Biochem J 2013. [DOI: 10.1042/bj20121485] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The human ABCG2 multidrug transporter actively extrudes a wide range of hydrophobic drugs and xenobiotics recognized by the transporter in the membrane phase. In order to examine the molecular nature of the transporter and its effects on the lipid environment, we have established an efficient protocol for the purification and reconstitution of the functional protein. We found that the drug-stimulated ATPase and the transport activity of ABCG2 are fully preserved by applying excess lipids and mild detergents during solubilization, whereas a detergent-induced dissociation of the ABCG2 dimer causes an irreversible inactivation. By using the purified and reconstituted protein we demonstrate that cholesterol is an essential activator, whereas bile acids are important modulators of ABCG2 activity. Both wild-type ABCG2 and its R482G mutant variant require cholesterol for full activity, although they exhibit different cholesterol sensitivities. Bile acids strongly decrease the basal ABCG2-ATPase activity both in the wild-type ABCG2 and in the mutant variant. These data reinforce the results for the modulatory effects of cholesterol and bile acids of ABCG2 investigated in a complex cell membrane environment. Moreover, these experiments open the possibility to perform functional and structural studies with a purified, reconstituted and highly active ABCG2 multidrug transporter.
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Kim YM, Park TS, Kim SG. The role of sphingolipids in drug metabolism and transport. Expert Opin Drug Metab Toxicol 2013; 9:319-31. [PMID: 23289866 DOI: 10.1517/17425255.2013.748749] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Sphingolipids represent a diverse class of lipid molecules. In addition to their function as membrane structural components, they serve as signaling molecules involved in various biological processes such as cell metabolism, growth, differentiation, stress and inflammatory responses and apoptosis. Sphingolipids may modulate the activity and/or expression of cytochrome P450s (CYPs) and transporters, which suggests that they may affect drug metabolism and excretion. AREAS COVERED In this review, the authors provide an overview of the properties of sphingolipid structures and metabolism. They also describe the effects of sphingolipids on the activity and expression of CYPs and transporters. In addition, the authors discuss the pathologic conditions where the sphingolipid metabolism is dysregulated particularly in association with inflammation and cancer. EXPERT OPINION Sphingolipidomic approaches have become accessible with the aid of advances in analytical technology. Sphingolipid profiles are modified by diseases, genetic disorders or certain drug treatment. The consequent changes in sphingolipid contents may alter the activities of detoxifying enzymes and those associated with cell viability. Since CYPs and transporters play roles in xenobiotics metabolism and excretion, sphingolipidomic information may be of use in understanding drug effect and toxicity.
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Affiliation(s)
- Young Mi Kim
- Seoul National University, Research Institute of Pharmaceutical Sciences, College of Pharmacy, San 56-1, Sillim-dong, Gwanak-gu, Seoul 151-742, Korea
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