1
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Abbasi S, Yousefi G, Tamaddon AM, Firuzi O. Paclitaxel-loaded polypeptide-polyacrylamide nanomicelles overcome drug-resistance by enhancing lysosomal membrane permeability and inducing apoptosis. J Biomed Mater Res A 2020; 109:18-30. [PMID: 32418316 DOI: 10.1002/jbm.a.37003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 04/11/2020] [Accepted: 04/19/2020] [Indexed: 02/06/2023]
Abstract
The aim of the current project was to investigate the in vitro properties of Paclitaxel (PTX)-loaded pHPMA5kD -pHis5kD -pLeu3kD nanomicelles (NMs) on multidrug resistance cell line. Circular dichroism analysis was done to investigate the effect of pH on the secondary structure of the copolymer. Cytotoxicity assay together with fluorescence imaging and flow cytometry were performed to get an insight about toxicity and cellular uptake mechanism of NMs. Acridine orange assay, rhodamine 123 (Rh123) accumulation assay, and apoptosis analysis were conducted for further investigation. It was found that the secondary structure of the copolymer changed in response to pH, PTX-loaded NMs had higher cytotoxicity on both drug-sensitive (MES-SA and MCF-7) and multidrug resistant cells (MES-SA/DX5) compared to free PTX, and interestinly free copolymer inhibited the growth of MES-SA/DX5 cells while it was nontoxic on drug-sensitive cells. Moreover, the copolymer was able to induce lysosome membrane permeation and increase Rh123 accumulation inside cells indicating inhibition of the P-gp efflux pumps. Finally, apoptosis was strongly induced in MES-SA/DX5 cells upon treatment with PTX-loaded NMs. It can be concluded that the designed hybrid copolymer is a good candidate for in vivo assay and developing a powerful system against multidrug resistance tumors.
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Affiliation(s)
- Sahar Abbasi
- Department of Pharmaceutics, School of Pharmacy, Hormozgan University of Medical Sciences, Bandar Abbas, Iran.,Department of Pharmaceutics, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Gholamhossein Yousefi
- Department of Pharmaceutics, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.,Center for Nanotechnology in Drug Delivery, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ali-Mohammad Tamaddon
- Center for Nanotechnology in Drug Delivery, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Omidreza Firuzi
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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2
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Domicevica L, Koldsø H, Biggin PC. Multiscale molecular dynamics simulations of lipid interactions with P-glycoprotein in a complex membrane. J Mol Graph Model 2018; 80:147-156. [PMID: 29353693 DOI: 10.1016/j.jmgm.2017.12.022] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
P-glycoprotein (P-gp) can transport a wide range of very different hydrophobic organic molecules across the membrane. Its ability to extrude molecules from the cell creates delivery problems for drugs that target proteins in the central nervous system (CNS) and also causes drug-resistance in many forms of cancer. Whether a drug will be susceptible to export by P-gp is difficult to predict and currently this is usually assessed with empirical and/or animal models. Thus, there is a need to better understand how P-gp works at the molecular level in order to fulfil the 3Rs: Refinement, reduction and replacement of animals in research. As structural information increasingly becomes available, our understanding at the molecular level improves. Proteins like P-gp are however very dynamic entities and thus one of the most appropriate ways to study them is with molecular dynamics simulations, especially as this can capture the influence of the surrounding environment. Recent parameterization developments have meant that it is now possible to simulate lipid bilayers that more closely resemble in vivo membranes in terms of their composition. In this report we construct a complex lipid bilayer that mimics the composition of brain epithelial cells and examine the interactions of it with P-gp. We find that the negatively charged phosphatidylserine lipids in the inner leaflet of the membrane tend to form an annulus around P-gp. We also observed the interaction of cholesterol with three distinct areas of the P-gp. Potential of mean force (PMF) calculations suggest that a crevice between transmembrane helices 10 and 12 has particularly favourable interaction energy for cholesterol.
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Affiliation(s)
- Laura Domicevica
- Structural Bioinformatics and Computational Biochemistry, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | - Heidi Koldsø
- Structural Bioinformatics and Computational Biochemistry, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | - Philip C Biggin
- Structural Bioinformatics and Computational Biochemistry, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom.
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3
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Domicevica L, Koldsø H, Biggin PC. Multiscale molecular dynamics simulations of lipid interactions with P-glycoprotein in a complex membrane. J Mol Graph Model 2017; 77:250-258. [PMID: 28903085 DOI: 10.1016/j.jmgm.2017.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/29/2017] [Accepted: 09/01/2017] [Indexed: 11/16/2022]
Abstract
P-glycoprotein (P-gp) can transport a wide range of very different hydrophobic organic molecules across the membrane. Its ability to extrude molecules from the cell creates delivery problems for drugs that target proteins in the central nervous system (CNS) and also causes drug-resistance in many forms of cancer. Whether a drug will be susceptible to export by P-gp is difficult to predict and currently this is usually assessed with empirical and/or animal models. Thus, there is a need to better understand how P-gp works at the molecular level in order to fulfil the 3Rs: Refinement, reduction and replacement of animals in research. As structural information increasingly becomes available, our understanding at the molecular level improves. Proteins like P-gp are however very dynamic entities and thus one of the most appropriate ways to study them is with molecular dynamics simulations, especially as this can capture the influence of the surrounding environment. Recent parameterization developments have meant that it is now possible to simulate lipid bilayers that more closely resemble in vivo membranes in terms of their composition. In this report we construct a complex lipid bilayer that mimics the composition of brain epithelial cells and examine the interactions of it with P-gp. We find that the negatively charged phosphatidylserine lipids in the inner leaflet of the membrane tend to form an annulus around P-gp. We also observed the interaction of cholesterol with three distinct areas of the P-gp. Potential of mean force (PMF) calculations suggest that a crevice between transmembrane helices 10 and 12 has particularly favourable interaction energy for cholesterol.
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Affiliation(s)
- Laura Domicevica
- Structural Bioinformatics and Computational Biochemistry, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | - Heidi Koldsø
- Structural Bioinformatics and Computational Biochemistry, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | - Philip C Biggin
- Structural Bioinformatics and Computational Biochemistry, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom.
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4
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Füredi A, Tóth S, Szebényi K, Pape VF, Türk D, Kucsma N, Cervenak L, Tóvári J, Szakács G. Identification and Validation of Compounds Selectively Killing Resistant Cancer: Delineating Cell Line–Specific Effects from P-Glycoprotein–Induced Toxicity. Mol Cancer Ther 2016; 16:45-56. [DOI: 10.1158/1535-7163.mct-16-0333-t] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 09/14/2016] [Accepted: 10/06/2016] [Indexed: 11/16/2022]
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5
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Li W, Tan XN, Luo T, Huang X, Wang Q, Yang YJ, Wang MJ, Liu LF. Formation of pH-responsive drug-delivery systems by electrospinning of vesicle-templated nanocapsule solutions. RSC Adv 2016. [DOI: 10.1039/c5ra26866d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A novel nanofibrous membrane, which contains chitosan/sodium alginate nanocapsules constructed by vesicle systems, has been fabricated via an electrospinning process as a drug-delivery system.
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Affiliation(s)
- W. Li
- Department of Chemistry
- Capital Normal University
- Beijing
- China
| | - X. N. Tan
- Department of Chemistry
- Capital Normal University
- Beijing
- China
| | - T. Luo
- Department of Chemistry
- Capital Normal University
- Beijing
- China
| | - X. Huang
- Department of Chemistry
- Capital Normal University
- Beijing
- China
| | - Q. Wang
- Department of Chemistry
- Capital Normal University
- Beijing
- China
| | - Y. J. Yang
- Department of Chemistry
- Capital Normal University
- Beijing
- China
| | - M. J. Wang
- Department of Chemistry
- Capital Normal University
- Beijing
- China
| | - L. F. Liu
- Department of Chemistry
- Capital Normal University
- Beijing
- China
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6
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Yildirim A, Turkaydin M, Garipcan B, Bayindir M. Cytotoxicity of multifunctional surfactant containing capped mesoporous silica nanoparticles. RSC Adv 2016. [DOI: 10.1039/c5ra21722a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This paper reports the synthesis of silica capped surfactant (CTAB) and dye (Rose Bengal; RB) containing mesoporous silica nanoparticles (MSNs).
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Affiliation(s)
- Adem Yildirim
- UNAM-National Nanotechnology Research Center
- Bilkent University
- 06800 Ankara
- Turkey
- Institute of Materials Science and Nanotechnology
| | - Muge Turkaydin
- Institute of Biomedical Engineering
- Bogazici University
- 34684 İstanbul
- Turkey
| | - Bora Garipcan
- Institute of Biomedical Engineering
- Bogazici University
- 34684 İstanbul
- Turkey
| | - Mehmet Bayindir
- UNAM-National Nanotechnology Research Center
- Bilkent University
- 06800 Ankara
- Turkey
- Institute of Materials Science and Nanotechnology
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7
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Li W, Luo T, Yang Y, Tan X, Liu L. Formation of controllable hydrophilic/hydrophobic drug delivery systems by electrospinning of vesicles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:5141-5146. [PMID: 25897828 DOI: 10.1021/la504796v] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Novel multifunctional poly(ethylene oxide) (PEO) nanofibrous membrane, which contains vesicles constructed by mixed surfactant cetyltrimethylammonium bromide (CTAB)/sodium dodecylbenzenesulfonate (SDBS), has been designed as dual drug-delivery system and fabricated via the electrospinning process. 5-FU and paeonolum, which are hydrophilic and hydrophobic anticancer model drugs, can be dissolved in vesicle solution's bond water and lipid bilayer membranes, respectively. The physicochemical properties of the electrospun nanofibrous membrane were systematically studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), and X-ray diffraction (XRD). Drug release behaviors of the electrospun nanofibrous membrane fabricated with different molar ratio of CTAB/SDBS vesicle solution were investigated. The result showed that the releasing amount of hydrophilic drug presented an ascending release manner, while the hydrophobic one showed a descending release behavior with increasing of the molar ratio of CTAB/SDBS. Moreover, the release amount of drugs from drug delivery system can be controlled by the molar ratio of CTAB/SDBS in the vesicle solution easily and conveniently. The distinct properties can be utilized to encapsulate environmental demanding and quantificational materials.
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Affiliation(s)
- Wei Li
- Department of Chemistry, Capital Normal University, Beijing 100048, China
| | - Tian Luo
- Department of Chemistry, Capital Normal University, Beijing 100048, China
| | - Yanjuan Yang
- Department of Chemistry, Capital Normal University, Beijing 100048, China
| | - Xiuniang Tan
- Department of Chemistry, Capital Normal University, Beijing 100048, China
| | - Lifei Liu
- Department of Chemistry, Capital Normal University, Beijing 100048, China
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8
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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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9
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Williams HD, Trevaskis NL, Charman SA, Shanker RM, Charman WN, Pouton CW, Porter CJH. Strategies to address low drug solubility in discovery and development. Pharmacol Rev 2013; 65:315-499. [PMID: 23383426 DOI: 10.1124/pr.112.005660] [Citation(s) in RCA: 985] [Impact Index Per Article: 89.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Drugs with low water solubility are predisposed to low and variable oral bioavailability and, therefore, to variability in clinical response. Despite significant efforts to "design in" acceptable developability properties (including aqueous solubility) during lead optimization, approximately 40% of currently marketed compounds and most current drug development candidates remain poorly water-soluble. The fact that so many drug candidates of this type are advanced into development and clinical assessment is testament to an increasingly sophisticated understanding of the approaches that can be taken to promote apparent solubility in the gastrointestinal tract and to support drug exposure after oral administration. Here we provide a detailed commentary on the major challenges to the progression of a poorly water-soluble lead or development candidate and review the approaches and strategies that can be taken to facilitate compound progression. In particular, we address the fundamental principles that underpin the use of strategies, including pH adjustment and salt-form selection, polymorphs, cocrystals, cosolvents, surfactants, cyclodextrins, particle size reduction, amorphous solid dispersions, and lipid-based formulations. In each case, the theoretical basis for utility is described along with a detailed review of recent advances in the field. The article provides an integrated and contemporary discussion of current approaches to solubility and dissolution enhancement but has been deliberately structured as a series of stand-alone sections to allow also directed access to a specific technology (e.g., solid dispersions, lipid-based formulations, or salt forms) where required.
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Affiliation(s)
- Hywel D Williams
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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10
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Saeed M, Greten HJ, Efferth T. Collateral Sensitivity in Drug-Resistant Tumor Cells. RESISTANCE TO TARGETED ANTI-CANCER THERAPEUTICS 2013. [DOI: 10.1007/978-1-4614-7070-0_10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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11
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Nanotechnology applied to overcome tumor drug resistance. J Control Release 2012; 162:45-55. [DOI: 10.1016/j.jconrel.2012.05.051] [Citation(s) in RCA: 238] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 05/29/2012] [Accepted: 05/31/2012] [Indexed: 01/01/2023]
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12
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He Q, Gao Y, Zhang L, Zhang Z, Gao F, Ji X, Li Y, Shi J. A pH-responsive mesoporous silica nanoparticles-based multi-drug delivery system for overcoming multi-drug resistance. Biomaterials 2011; 32:7711-20. [DOI: 10.1016/j.biomaterials.2011.06.066] [Citation(s) in RCA: 287] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 06/26/2011] [Indexed: 10/17/2022]
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13
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He Q, Gao Y, Zhang L, Bu W, Chen H, Li Y, Shi J. One-pot self-assembly of mesoporous silica nanoparticle-based pH-responsive anti-cancer nano drug delivery system. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm13598h] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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14
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Cianetti S, Cooper VB, Attenni B, Pucci V, Fiore F, Giuliano C, Laufer R, Gardelli C, Monteagudo E, Narjes F, Pearce GE, Rowley M. Enhancement of intestinal absorption of 2-methyl cytidine prodrugs. Drug Deliv 2010; 17:214-22. [PMID: 20233089 DOI: 10.3109/10717541003667814] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The purpose of this study was to investigate the in vivo absorption enhancement of a nucleoside (phosphoramidate prodrug of 2'-methyl-cytidine) anti-viral agent of proven efficacy by means of intestinal permeation enhancers. Natural nucleosides are hydrophilic molecules that do not rapidly penetrate cell membranes by diffusion and their absorption relies on specialized transporters. Therefore, the oral absorption of nucleoside prodrugs and the target organ concentration of the biologically active nucleotide can be limited due to poor permeation across the intestinal epithelium. In the present study, the specificity, concentration dependence, and effect of four classes of absorption promoters, i.e. fatty acids, steroidal detergents, mucoadhesive polymers, and secretory transport inhibitors, were evaluated in a rat in vivo model. Sodium caprate and alpha-tocopheryl-polyethyleneglycol-1000-succinate (TPGS) showed a significant effect in increasing liver concentration of nucleotide (5-fold). These results suggested that both excipients might be suited in a controlled release matrix for the synchronous release of the drug and absorption promoter directly to the site of absorption and highlights that the effect is strictly dependent on the absorption promoter dose. The feasibility of such a formulation approach in humans was evaluated with the aim of developing a solid dosage form for the peroral delivery of nucleosides and showed that these excipients do provide a potential valuable tool in pre-clinical efficacy studies to drive discovery programs forward.
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Affiliation(s)
- Simona Cianetti
- IRBM, Merck Research Laboratories, Via Pontina Km 30600, 00040, Pomezia (RM), Italy.
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15
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Dong X, Mumper RJ. Nanomedicinal strategies to treat multidrug-resistant tumors: current progress. Nanomedicine (Lond) 2010; 5:597-615. [PMID: 20528455 DOI: 10.2217/nnm.10.35] [Citation(s) in RCA: 245] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Multidrug resistance (MDR) is a major impediment to the success of cancer chemotherapy. P-glycoprotein is an important and the best-known membrane transporter involved in MDR. Several strategies have been used to address MDR, especially P-glycoprotein-mediated drug resistance in tumors. However, clinical success has been limited, largely due to issues regarding lack of efficacy and/or safety. Nanoparticles have shown the ability to target tumors based on their unique physical and biological properties. To date, nanoparticles have been investigated primarily to address P-glycoprotein and the observed improved anticancer efficacy suggests that nanomedicinal strategies provide a new opportunity to overcome MDR. This article focuses on nanotechnology-based formulations and current nanomedicine approaches to address MDR in tumors and discusses the proposed mechanisms of action.
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Affiliation(s)
- Xiaowei Dong
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536-0082, USA
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16
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Sreeramulu K, Liu R, Sharom FJ. Interaction of insecticides with mammalian P-glycoprotein and their effect on its transport function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1750-7. [PMID: 17490606 DOI: 10.1016/j.bbamem.2007.04.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Revised: 03/26/2007] [Accepted: 04/02/2007] [Indexed: 11/21/2022]
Abstract
We studied the effects of four commonly used insecticides (methylparathion, endosulfan, cypermethrin and fenvalerate) on P-glycoprotein isolated from multidrug-resistant cells. All the pesticides stimulated P-glycoprotein ATPase activity, with maximum stimulation of up to 213% in a detergent-solubilized preparation, and up to 227% in reconstituted liposomes. The ATPase stimulation profiles were biphasic, displaying lower stimulation, and in the case of methylparathion, inhibition of activity, at higher insecticide concentrations. Quenching of the intrinsic Trp fluorescence of purified P-glycoprotein was used to quantitate insecticide binding; the estimated K(d) values fell in the range 4-6 microM. Transport of the fluorescent substrate tetramethylrosamine (TMR) into proteoliposomes containing P-glycoprotein was monitored in real time. The TMR concentration gradient generated by the transporter was collapsed by the addition of insecticides, and prior addition of these compounds prevented its formation. The rate of TMR transport was inhibited in a saturable fashion by all the compounds, indicating that they compete with the substrate for membrane translocation. Taken together, these data suggest that the insecticides bind to Pgp with high affinity and effectively block drug transport. Inhibition of Pgp by pesticides may compromise its ability to clear xenobiotics from the body, leading to a higher risk of toxicity.
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Affiliation(s)
- K Sreeramulu
- Department of Biochemistry, Gulbarga University, Gulbarga-585 106, India
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17
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Zastre J, Jackson JK, Wong W, Burt HM. Methoxypolyethylene Glycol-block-polycaprolactone Diblock Copolymers Reduce P-glycoprotein Efflux in the Absence of a Membrane Fluidization Effect while Stimulating P-glycoprotein ATPase Activity. J Pharm Sci 2007; 96:864-75. [PMID: 17094135 DOI: 10.1002/jps.20785] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We have previously shown that amphiphilic diblock copolymers composed of methoxypolyethylene glycol-b-polycaprolactone (MePEG-b-PCL) increased the cellular accumulation and reduced the basolateral to apical flux of the P-glycoprotein substrate, rhodamine 123 (R-123) in caco-2 cells. The purpose of this study was to investigate membrane perturbation effects of MePEG-b-PCL diblock copolymers with erythrocyte membranes and caco-2 cells and the effect on P-gp ATPase activity. The diblock copolymer MePEG(17)-b-PCL(5) induced increasing erythrocyte hemolysis at concentrations which correlated with increasing accumulation of R-123 into caco-2 cells. However, no increase in cellular accumulation of R-123 by non-P-gp expressing cells was observed, suggesting that diblock did not enhance the transmembrane passive diffusion of R-123, but that the accumulation enhancement effect of the diblock in caco-2 cells was likely mediated primarily via P-gp inhibition. Fluorescence anisotropy measurements of membrane fluidity and P-gp ATPase activity demonstrated that MePEG(17)-b-PCL(5) decreased caco-2 membrane fluidity while stimulating ATPase activity approximately threefold at concentrations that maximally enhanced R-123 caco-2 accumulation. These results suggest that inhibition of P-gp efflux by MePEG(17)-b-PCL(5) does not appear to be related to increases in membrane fluidity or through inhibition in P-gp ATPase activities, which are two commonly reported cellular effects for P-gp inhibition mediated by surfactants.
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Affiliation(s)
- Jason Zastre
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College St. Toronto, Ontario, Canada M5S 3M2
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18
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Seelig A, Gerebtzoff G. Enhancement of drug absorption by noncharged detergents through membrane and P-glycoprotein binding. Expert Opin Drug Metab Toxicol 2006; 2:733-52. [PMID: 17014392 DOI: 10.1517/17425255.2.5.733] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Noncharged detergents are used as excipients in drug formulations. Until recently, they were considered as inert compounds, enhancing drug absorption essentially by improving drug solubility. However, many detergents insert into lipid membranes, although to different extents, and change the lateral packing density of membranes at high concentrations. Moreover, they bind to the efflux transporter P-glycoprotein (P-gp) and most likely to related transporters and metabolising enzymes with overlapping substrate specificities. If their affinity to P-gp is higher than that of the coadministered drug they act as modulators or inhibitors of P-gp and enhance drug absorption. Inhibition of P-gp and related proteins can, however, cause severe side effects. This paper first reviews the membrane binding propensity of different noncharged detergents (including poloxamers) and discusses their ability to bind to P-gp. Second, literature data on drug uptake enhancement by noncharged detergents, obtained in vivo and in vitro, are analysed at the molecular level. The present analysis provides the tools for an approximate and simple prior estimate of the membrane and P-gp binding ability of noncharged detergents based on a modular binding approach.
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Affiliation(s)
- Anna Seelig
- Biozentrum, Biophysical Chemistry, University of Basel, Klingelbergstrasse 70, CH-4057 Basel, Switzerland.
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19
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Radeva G, Perabo J, Sharom FJ. P-Glycoprotein is localized in intermediate-density membrane microdomains distinct from classical lipid rafts and caveolar domains. FEBS J 2005; 272:4924-37. [PMID: 16176266 DOI: 10.1111/j.1742-4658.2005.04905.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
P-glycoprotein (Pgp), a member of the ATP-binding cassette (ABC) superfamily responsible for the ATP-driven extrusion of diverse hydrophobic molecules from cells, is a cause of multidrug resistance in human tumours. Pgp can also operate as a phospholipid and glycosphingolipid flippase, and has been functionally linked to cholesterol, suggesting that it might be associated with sphingolipid-cholesterol microdomains in cell membranes. We have used nonionic detergent extraction and density gradient centrifugation of extracts from the multidrug-resistant Chinese hamster ovary cell line, CH(R)B30, to address this question. Our data indicate that Pgp is localized in intermediate-density membrane microdomains different from classical lipid rafts enriched in Src-family kinases. We demonstrate that Brij-96 can selectively isolate the Pgp domains, separating them from the caveolar and classical lipid rafts. Pgp was found entirely in the Brij-96-insoluble domains, and only partially in the Triton X-100-insoluble membrane microdomains. We studied the sensitivity of these domains to cholesterol removal, as well as their relationship to GM(1) ganglioside- and caveolin-1-enriched caveolar domains. We found that the buoyant density of the Brij-96-based Pgp-containing microdomains was sensitive to cholesterol removal by methyl-beta-cyclodextrin. The Brij-96 domains retained their structural integrity after cholesterol depletion while, in contrast, the Triton X-100-based caveolin-1/GM(1) microdomains did not. Using confocal fluorescence microscopy, we determined that caveolin-1 and GM(1) colocalized, while Pgp and caveolin-1, or Pgp and GM(1), did not. Our results suggest that Pgp does not interact directly with caveolin-1, and is localized in intermediate-density domains, distinct from classical lipid rafts and caveolae, which can be isolated using Brij-96.
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Affiliation(s)
- Galina Radeva
- Department of Molecular and Cellular Biology, University of Guelph, Ontario, Canada
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Castaing M, Loiseau A, Djoudi L. Effects of cholesterol on dye leakage induced by multidrug-resistance modulators from anionic liposomes. Eur J Pharm Sci 2003; 18:81-8. [PMID: 12554076 DOI: 10.1016/s0928-0987(02)00243-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Multidrug-resistance (MDR) in cancer cells is often associated with marked changes in the membrane cholesterol levels. To assess the cholesterol-dependence of MDR modulator efficiency in terms of the drug-membrane interactions, the ability of 5 MDR-modulators to induce the leakage of Sulphan blue through anionic liposomes was quantified at various mole fractions x(chol) of cholesterol (0-0.42). Depending on the electric charge of the drug, cholesterol modified to a large extent either the permeation dose inducing 50% dye leakage (PD(50)) or the co-operativity (h) of the permeation process. The PD(50) of Triton X-100 (non-ionic) and that of diltiazem and verapamil (mono-basic amines) varied only slightly (0.3 mM) with the cholesterol level, whereas the co-operativity increased by 1.9-2.7. On the reverse, the PD(50) of a thioacridine derivative and mepacrine (di-basic amines) increased by 4.8-7.5 mM in the cholesterol range investigated, whereas the co-operativity (h) increased slightly (0.2-0.7). In the permeation process, the rate-limiting character of the electric charge (z) of the drug is likely to be strengthened by high cholesterol levels. The results provide evidence that in resistant tumours exhibiting high cholesterol levels, the MDR might be reversed by favourable drug-membrane interactions if the modulators are designed in the form of highly lipophilic mono-basic drugs that counteract the effects of cholesterol on the membrane dipolar potential and membrane fluidity.
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Affiliation(s)
- Madeleine Castaing
- GERCTOP-UMR6009, Faculté de Pharmacie, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 05, France.
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Castaing M, Loiseau A, Dani M. Designing multidrug-resistance modulators circumventing the reverse pH gradient in tumours. J Pharm Pharmacol 2001; 53:1021-8. [PMID: 11480537 DOI: 10.1211/0022357011776270] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Multidrug-resistant tumours often exhibit a reverse pH gradient (acid outside), as they have an acid extracellular pH (pHe) and a neutral alkaline intracellular pH (pHi). This study was designed to test the hypothesis that the ability of lipophilic drugs to mediate multidrug resistance (MDR) reversal by interacting with the membrane phospholipids may be correlated with pH in resistant tumours. The permeation properties of five MDR modulators were therefore studied at 37 degrees C by quantifying their ability to induce the leakage of Sulfan blue through unilamellar anionic liposomes, over the range pH 6.5-7.7, and in the absence of any membrane potential (pHe = pHi). The dye leakage induced by two calcium blockers (diltiazem and verapamil) and two antiparasitic agents (thioacridine derivative and mepacrine) was found to significantly increase with the pH of the medium (P < 0.001), whereas that induced by a non-ionic detergent (Triton X-100) showed almost no pH-dependent variations. This process was a cooperative one (0.8 < Hill coefficient < 8.5) and the permeation doses inducing 50% dye leakage (PD50) ranged from 1.6 to 36.0 mM. The permeation ability of the MDR modulators (log(1/PD50)) significantly increased with their octanol-buffer distributions (logD) (slope = 0.35+/-0.06; y intercept = 1.65 +/- 0.14; P < 0.0001) and significantly decreased with their net electric charge (z) (slope = -0.48+/-0.07; y intercept = 2.85+/-0.08; P < 0.0001). A highly significant multiple correlation was found to exist between the variations of log(1/PD50) with those of logD and z (dlog(1/PD50)/dlogD = 0.21 +/- 0.05; dlog(1/PD50)/dz = -0.34+/-0.07; y intercept = 2.27+/-0.17; P < 0.000001). The results provide evidence that in resistant tumours (acid pHe and neutral alkaline pHi), the MDR reversal might be enhanced by favourable drug-membrane interactions if the modulators are designed in the form of highly lipophilic (logP approximately equals 4) mono-basic drugs with a near neutral pKa (pKa approximately equals 7-8).
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Affiliation(s)
- M Castaing
- GERCTOP-ESA6009, Faculté de Pharmacie, Marseille, France.
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Aszalos A. Modulation of Multidrug Resistance in Cancer by Immunosuppresive Agents. Preclinical Studies. Pathol Oncol Res 2001; 1:64-70. [PMID: 11173570 DOI: 10.1007/bf02893586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This is a brief summary of the status of known immunosuppressive drugs describing their potential and mode of action to reverse the function of the MDR1 gene product, the P glycoprotein. Different aspects of these immunosuppressors have been reviewed in the recent literature. This summary will focus only on those studies which relate to the effect of these drugs on the P-glycoprotein. In addition, studies which may explain the mode of action, but do not deal directly with P-glycoprotein, are also summarized.
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Castaing M, Loiseau A, Dani M. Thermal dependence of multidrug-resistant-modulator efficiency: a study in anionic liposomes. J Pharm Pharmacol 2000; 52:1171-8. [PMID: 11092560 DOI: 10.1211/0022357001777298] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
This study was designed to test the hypothesis that there exists a correlation between the ability of lipophilic drugs to mediate the reversal of multidrug-resistance (MDR) by interacting with the membrane phospholipids and the metabolic level in tissues. The permeation properties of five MDR-modulators were studied by quantifying their ability to induce the leakage of Sulphan blue through unilamellar liposomes, over the temperature range 27-42 degrees C. The dye leakage induced by a non-ionic detergent (Triton X-100), two calcium blockers (diltiazem and verapamil) and two antiparasitic agents (thioacridine derivative and mepacrine) was temperature-dependent. The permeation process was a co-operative one (1.1 < Hill coefficient < 7.5) and the permeation doses inducing 50% dye leakage (PD50) were 1.5 - 14.9 mM. The permeation ability of the MDR-modulators (log(1/PD50)) decreased significantly as the net electric charge (z) increased. The passive dye leakage (deltaG < 0) was found to be an endothermic process (deltaH > 0), favoured by an increase in the membrane disorder (deltaS > 0). The apparent enthalpy factor (deltaH50) associated with 50% dye leakage increased with the net electric charge of the compound, and this energetically non-favoured event was entirely offset by the concomitant increase in the entropy factor (deltaS50). The apparent permeation enthalpy (deltaH50) and entropy (deltaS50) showed the lowest values for Triton X-100 (deltaH50 = 7.1 +/- 0.53 kJ mol(-1), deltaS50 = 76.9 +/- 1.86 Jmol(-1) K(-1)), and the highest values for mepacrine (deltaH50 = 79.5 +/- 3.80 kJmol(-1), deltaS50 = 306.7 +/- 5-97 J mol(-1) K(-1)). When the temperature was increased from 27 to 42 degrees C, the apparent Gibbs free energy (deltaG50) of the dye leakage induced by Triton X-100 decreased by less than 10% of the initial value, and that induced by mepacrine decreased by nearly 40%. The results provide evidence that in tissues with high metabolic levels and therefore high temperatures, MDR-reversal is likely to be enhanced via favourable drug-membrane interactions controlled by the electric charge of the modulators.
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Affiliation(s)
- M Castaing
- GERCTOP-ESA6009, Faculté de Pharmacie, Marseille, France.
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Crandall I, Charuk J, Kain KC. Nonylphenolethoxylates as malarial chloroquine resistance reversal agents. Antimicrob Agents Chemother 2000; 44:2431-4. [PMID: 10952591 PMCID: PMC90081 DOI: 10.1128/aac.44.9.2431-2434.2000] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Malaria-associated morbidity and mortality are increasing because of widespread resistance to one of the safest and least expensive antimalarials, chloroquine. The availability of an inexpensive agent that is capable of reversing chloroquine resistance would have a major impact on malaria treatment worldwide. The interaction of nonylphenolethoxylates (NPEs, commercially available synthetic surfactants) with drug-resistant Plasmodium falciparum was examined to determine if NPEs inhibited the growth of the parasites and if NPEs could sensitize resistant parasites to chloroquine. NPEs inhibited the development of the parasite when present in the low- to mid-micromolar range (5 to 90 microM), indicating that they possess antimalarial activity. Further, the presence of <10 microM concentrations of NPEs caused the 50% inhibitory concentrations for chloroquine-resistant lines to drop to levels (< or =12 nM) observed for sensitive lines and generally considered to be achievable with treatment courses of chloroquine. Long-chain (>30 ethoxylate units) NPEs were found to be most active in P. falciparum, which contrasts with previously observed maximal activity of short-chain ( approximately 9 ethoxylate units) NPEs in multidrug-resistant mammalian cell lines. NPEs may be attractive chloroquine resistance reversal agents since they are inexpensive and may be selectively directed against P. falciparum without inhibiting mammalian tissue P glycoproteins. Antimalarial preparations that include these agents may prolong the effective life span of chloroquine and other antimalarials.
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Affiliation(s)
- I Crandall
- Tropical Disease Unit, The Toronto Hospital, University of Toronto, Ontario, Canada.
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Ferté J. Analysis of the tangled relationships between P-glycoprotein-mediated multidrug resistance and the lipid phase of the cell membrane. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:277-94. [PMID: 10632698 DOI: 10.1046/j.1432-1327.2000.01046.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
P-glycoprotein (Pgp), the so-called multidrug transporter, is a plasma membrane glycoprotein often involved in the resistance of cancer cells towards multiple anticancer agents in the multidrug-resistant (MDR) phenotype. It has long been recognized that the lipid phase of the plasma membrane plays an important role with respect to multidrug resistance and Pgp because: the compounds involved in the MDR phenotype are hydrophobic and diffuse passively through the membrane; Pgp domains involved in drug binding are located within the putative transmembrane segments; Pgp activity is highly sensitive to its lipid environment; and Pgp may be involved in lipid trafficking and metabolism. Unraveling the different roles played by the membrane lipid phase in MDR is relevant, not only to the evaluation of the precise role of Pgp, but also to the understanding of the mechanism of action and function of Pgp. With this aim, I review the data from different fields (cancer research, medicinal chemistry, membrane biophysics, pharmaceutical research) concerning drug-membrane, as well as Pgp-membrane, interactions. It is emphasized that the lipid phase of the membrane cannot be overlooked while investigating the MDR phenotype. Taking into account these aspects should be useful in the search of ways to obviate MDR and could also be relevant to the study of other multidrug transporters.
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Affiliation(s)
- J Ferté
- Service de Biophysique des Protéines et des Membranes, DSV-DBCM-SBPM, CEA, Centre de Saclay, Gif-sur-Yvette, France.
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Sharom FJ, Yu X, Lu P, Liu R, Chu JW, Szabó K, Müller M, Hose CD, Monks A, Váradi A, Seprôdi J, Sarkadi B. Interaction of the P-glycoprotein multidrug transporter (MDR1) with high affinity peptide chemosensitizers in isolated membranes, reconstituted systems, and intact cells. Biochem Pharmacol 1999; 58:571-86. [PMID: 10413294 DOI: 10.1016/s0006-2952(99)00139-2] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
P-glycoprotein-mediated multidrug resistance can be reversed by the action of a group of compounds known as chemosensitizers. The interactions with P-glycoprotein of two novel hydrophobic peptide chemosensitizers (reversins 121 and 205) have been studied in model systems in vitro, and in a variety of MDR1-expressing intact tumor cells. The reversins bound to purified P-glycoprotein with high affinity (77-154 nM), as assessed by a quenching assay using fluorescently labeled purified protein. The peptides modulated P-glycoprotein ATPase activity in Sf9 insect cell membranes expressing human MDR1, plasma membrane vesicles from multidrug-resistant cells, and reconstituted proteoliposomes. Both peptides induced a large stimulation of ATPase activity; however, higher concentrations, especially of reversin 205, led to inhibition. This pattern was different from that of simple linear peptides, and resembled that of chemosensitizers such as verapamil. In both membrane vesicles and reconstituted proteoliposomes, 1-2 microM reversins were more effective than cyclosporin A at blocking colchicine transport. Reversin 121 and reversin 205 restored the uptake of [3H]daunorubicin and rhodamine 123 in MDR1-expressing cells to the level observed in the drug-sensitive parent cell lines, and also effectively inhibited the extrusion of calcein acetoxymethyl ester from intact cells. In cytotoxicity assays, reversin 121 and reversin 205 eliminated the resistance of MDR1-expressing tumor cells against MDR1-substrate anticancer drugs, and they had no toxic effects in MDR1-negative control cells. We suggest that peptides of the reversin type interact with the MDR1 protein with high affinity and specificity, and thus they may be good candidates for the development of MDR1-modulating agents to sensitize drug resistance in cancer.
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Affiliation(s)
- F J Sharom
- Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, Department of Chemistry and Biochemistry, University of Guelph, Ontario, Canada.
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Eytan GD, Kuchel PW. Mechanism of action of P-glycoprotein in relation to passive membrane permeation. INTERNATIONAL REVIEW OF CYTOLOGY 1999; 190:175-250. [PMID: 10331240 DOI: 10.1016/s0074-7696(08)62148-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This review presents a survey of studies of the movement of chemotherapeutic drugs into cells, their extrusion from multidrug-resistant (MDR) cells overexpressing P-glycoprotein (Pgp), and the mode of sensitization of MDR cells to anticancer drugs by Pgp modulators. The consistent features of the kinetics from studies of the operation of Pgp in cells were combined in a computer model that enables the simulation of experimental scenarios. MDR-type drugs are hydrophobic and positively charged and as such bind readily to negatively charged phospholipid head groups of the membrane. Transmembrane movement of MDR-type drugs, such as doxorubicin, occurs by a flip-flop mechanism with a lifetime of about 1 min rather than by diffusion down a gradient present in the lipid core. A long residence time of a drug in the membrane leaflet increases the probability that P-glycoprotein will remove it from the cell. In a manner similar to ion-transporting ATPases, such as Na+,K(+)-ATPase, Pgp transports close to one drug molecule per ATP molecule hydrolyzed. Computer simulation of cellular pharmacokinetics, based on partial reactions measured in vitro, show that the efficiency of Pgp, in conferring MDR on cells, depends on the pumping capacity of Pgp and its affinity toward the specific drug, the transmembrane movement rate of the drug, the affinity of the drug toward its pharmacological cellular target, and the affinity of the drug toward intracellular trapping sites. Pgp activities present in MDR cells allow for the efficient removal of drugs, whether directly from the cytoplasm or from the inner leaflet of the plasma membrane. A prerequisite for a successful modulator, capable of overcoming cellular Pgp, is the rapid passive transbilayer movement, allowing it to reenter the cell immediately and thus successfully occupy the Pgp active site(s).
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Affiliation(s)
- G D Eytan
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
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Regev R, Assaraf YG, Eytan GD. Membrane fluidization by ether, other anesthetics, and certain agents abolishes P-glycoprotein ATPase activity and modulates efflux from multidrug-resistant cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 259:18-24. [PMID: 9914470 DOI: 10.1046/j.1432-1327.1999.00037.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The anesthetics benzyl alcohol and the nonaromatic chloroform and diethyl ether, abolish P-glycoprotein (Pgp) ATPase activity in a mode that does not fit classical competitive, noncompetitive, or uncompetitive inhibition. At concentrations similar to those required for inhibition of ATPase activity, these anesthetics fluidize membranes leading to twofold acceleration of doxorubicin flip-flop across lipid membranes and prevent photoaffinity labeling of Pgp with [125I]-iodoarylazidoprazosin. Similar concentrations of ether proved nontoxic and modulated efflux from Pgp-overexpressing cells. A similar twofold acceleration of doxorubicin flip-flop rate across membranes was observed with neutral mild detergents, including Tween 20, Nonidet P-40 and Triton X-100, and certain Pgp modulators, such as verapamil and progesterone. Concentrations of these agents, similar to those required for membrane fluidization, inhibited Pgp ATPase activity in a mode similar to that observed with the anesthetics. The mode of inhibition, i.e. lack of evidence for classical enzyme inhibition and the correlation of Pgp ATPase inhibition with membrane fluidization over a wide range of concentrations and structures of drugs favors the direct inhibition of Pgp ATPase activity by membrane fluidization. The unusual sensitivity of Pgp to membrane fluidization, as opposed to acceleration of ATPase activity of ion transporters, could fit the proposed function of Pgp as a 'flippase', which is in close contact with the membrane core.
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Affiliation(s)
- R Regev
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
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Sharom FJ, Lu P, Liu R, Yu X. Linear and cyclic peptides as substrates and modulators of P-glycoprotein: peptide binding and effects on drug transport and accumulation. Biochem J 1998; 333 ( Pt 3):621-30. [PMID: 9677321 PMCID: PMC1219625 DOI: 10.1042/bj3330621] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
One cause of multidrug resistance (MDR) in human cancers is the overexpression of the P-glycoprotein multidrug transporter, a member of the ABC superfamily of membrane proteins. Natural products and chemotherapeutic drugs are pumped out of the cell by P-glycoprotein in an ATP-dependent fashion. There is growing evidence that many hydrophobic peptides are also P-glycoprotein substrates. With the use of a fluorescence-quenching assay, we have shown that some linear and cyclic hydrophobic peptides interact with P-glycoprotein, whereas others do not. The measured values of the quenching constant, Kq, for interaction of peptides with P-glycoprotein ranged from 200 nM for cyclosporine A to 138 microM for the tripeptide N-acetyl-leucyl-leucyl-norleucinal. Peptides that interacted with P-glycoprotein in the fluorescence assay also blocked colchicine transport into plasma membrane vesicles from MDR cells. The values of Dm, the peptide concentration causing 50% inhibition of drug uptake, were highly correlated with the values of Kq, over three orders of magnitude. The P-glycoprotein ATPase stimulation/inhibition profile of the peptides was not helpful in making a quantitative assessment of the ability of a peptide to interact with P-glycoprotein or to block drug transport. Some hydrophobic peptides were able to restore accumulation in MDR cells of the chemotherapeutic drug daunorubicin and the fluorescent dye rhodamine 123 to the levels observed in the drug-sensitive parent. Peptides that interacted with P-glycoprotein also displayed a relatively low overall toxicity to intact MDR cells, and inhibited drug transport at concentrations below the toxic range. Hydrophobic peptides should be given serious consideration for development as clinical chemosensitizing agents.
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Affiliation(s)
- F J Sharom
- Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, Department of Chemistry and Biochemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
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Charuk MH, Grey AA, Reithmeier RA. Identification of the synthetic surfactant nonylphenol ethoxylate: a P-glycoprotein substrate in human urine. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:F1127-39. [PMID: 9841506 DOI: 10.1152/ajprenal.1998.274.6.f1127] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
P-glycoprotein (Mdr1p) is an ATP-dependent drug efflux pump that is overexpressed in multidrug-resistant cells and some cancers. Mdr1p is also expressed in normal tissues like the kidney, where it can mediate transepithelial drug transport. A human urinary compound that reverses multidrug resistance and blocks [3H]azidopine photolabeling of P-glycoprotein was purified to homogeneity and identified by 1H-NMR and mass spectrometry as the synthetic surfactant nonylphenol ethoxylate (NPE). Multidrug-resistant Chinese hamster ovary (CHO) C5 cells accumulated less [3H]NPE than parental drug-sensitive Aux-B1 cells, and Mdr1p substrates, verapamil and cyclosporin A, increased this surfactant's accumulation in C5 cells. NPE blocked the net transepithelial transport (basolateral to apical) of [3H]cyclosporin A in epithelia formed by Madin-Darby canine kidney (MDCK) cells. Net transepithelial transport (basal to apical) of [3H]NPE was demonstrated in MDCK cells and was inhibited by cyclosporin A. These findings show NPE is a Mdr1p substrate excreted into urine by kidney P-glycoprotein. NPE is a widely used surfactant and a known hormone disrupter that is readily absorbed orally or topically. The current findings indicate the function of kidney Mdr1p may be to eliminate exogenous compounds from the body.
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Affiliation(s)
- M H Charuk
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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Sharom FJ, Yu X, DiDiodato G, Chu JW. Synthetic hydrophobic peptides are substrates for P-glycoprotein and stimulate drug transport. Biochem J 1996; 320 ( Pt 2):421-8. [PMID: 8973548 PMCID: PMC1217947 DOI: 10.1042/bj3200421] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
P-Glycoprotein functions as an ATP-driven active efflux pump for many natural products and chemotherapeutic drugs. Hydrophobic peptides have been shown to block drug uptake by P-glycoprotein, indicating that they might be transport substrates. The present study examines the interaction of the synthetic peptide series NAc-LnY-amide with the multidrug transporter. Several peptides in this series caused up to 3.5-fold enhancement of colchicine accumulation in membrane vesicles from multidrug resistant (MDR) cells, which suggests the existence of novel interactions between the binding sites for peptides and drug. Peptides did not stimulate vinblastine transport, which was inhibited as expected for competing substrates. These peptides displayed modest stimulatory effects on the ATPase activity of P-glycoprotein. None blocked azidopine photoaffinity labelling, showing that they probably occupy a binding site separate from that for the drug. Studies with 125I-labelled NAc-LLY-amide showed that it was transported by P-glycoprotein in both membrane vesicles and reconstituted proteoliposomes. Uptake of the peptide was rapid, saturable, osmotically sensitive and occurred against a concentration gradient. The enhancing effect of NAc-LLY-amide on colchicine transport was reciprocated, i.e. colchicine greatly increased the transport of labelled peptide by P-glycoprotein. Peptide transport was also modulated, both positively and negatively, by other MDR spectrum drugs. It is concluded that linear hydrophobic peptides are indeed transported by P-glycoprotein, and some have interactions with drug substrates that result in mutual stimulation of transport.
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Affiliation(s)
- F J Sharom
- Guelph-Waterloo Centre for Graduate Work in Chemistry, Department of Chemistry and Biochemistry, University of Guelph, Ontario, Canada
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Borrel MN, Fiallo M, Veress I, Garnier-Suillerot A. The effect of crown ethers, tetraalkylammonium salts, and polyoxyethylene amphiphiles on pirarubicin incorporation in K562 resistant cells. Biochem Pharmacol 1995; 50:2069-76. [PMID: 8849334 DOI: 10.1016/0006-2952(95)02112-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The basic distinguishing feature of all cells expressing functional P-glycoprotein-multidrug resistance (P-gp-MDR) is a decrease in steady-state accumulation drug levels as compared to drug-sensitive controls. In an attempt to identify mechanism(s) by which MDR can be circumvented, we examined the cellular accumulation, in resistant cells, of 4'-O-tetrahydropyranyl-doxorubicin (pirarubicin) alone and in conjunction with various molecules belonging to three different classes: the crown ethers, the tetraalkylammonium salts, and the polyoxethylene amphiphiles. The present study was performed using a spectrofluorometric method which enabled us to follow the uptake and release of fluorescent molecules by living cells while the cells were being incubated with the drug. Erythroleukemia K562 cell lines were used. Our data show that the compounds of these three completely different classes were able to increase the incorporation of pirarubicin provided they had a minimum degree of lipophilicity. Study of the growth inhibitory activity of these compounds revealed that cross-resistance to the tetraalkyl ammonium salt increased with the lipophilicity and was equal to 58 for tetraoctylammonium salt, the most lipophilic compound of this series. This demonstrates that neither the presence of a positive charge nor an aromatic moiety is required for MDR recognition.
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Affiliation(s)
- M N Borrel
- Laboratoire de Physico-chimie Biomoléculaire et Cellulaire (URA CNRS 2056) UFR Léonard de Vinci, Université Paris Nord, Bobigny, France
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Gain and loss of hypersensitivity to resistance modifiers in multidrug resistant chinese hamster ovary cells. Cancer Lett 1995. [DOI: 10.1016/s0304-3835(06)80019-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sharom FJ, DiDiodato G, Yu X, Ashbourne KJ. Interaction of the P-glycoprotein multidrug transporter with peptides and ionophores. J Biol Chem 1995; 270:10334-41. [PMID: 7730340 DOI: 10.1074/jbc.270.17.10334] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
P-glycoprotein functions as an ATP-driven active efflux pump for many cytotoxic drugs. We now show that hydrophobic peptides and ionophores also interact with the multidrug transporter. Multidrug-resistant cells are cross-resistant to several hydrophobic peptides and ionophores, but not to some other membrane-active species. Linear peptides, cyclic peptides, and ionophores stimulated the ATPase activity of P-glycoprotein in plasma membrane vesicles by up to 2.5-fold. Drugs and chemosensitizers were able to block P-glycoprotein ATPase stimulation by verapamil, however, peptides and ionophores (with the exception of cyclosporine A) were unable to do so. Peptides and ionophores also effectively inhibited ATP-dependent drug transport by P-glycoprotein in plasma membrane vesicles. The median effect analysis was used to extract quantitative parameters from the drug transport inhibition data. Unlike drug substrates and cyclic peptides, linear peptides did not inhibit photoaffinity labeling of P-glycoprotein by [3H]azidopine. Taken together, these results indicate that certain hydrophobic peptides and ionophores are P-glycoprotein substrates, however, they affect the transporter in a different manner from drugs. Linear peptides interact with P-glycoprotein at a site distinct from those for verapamil and azidopine, whereas the interaction site for cyclic peptides and ionophores appears to be linked to these sites to varying degrees. Export of hydrophobic peptides may be an important physiological function of P-glycoprotein.
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Affiliation(s)
- F J Sharom
- Guelph-Waterloo Centre for Graduate Work in Chemistry, Department of Chemistry and Biochemistry, University of Guelph, Ontario, Canada
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Sharom FJ. Characterization and functional reconstitution of the multidrug transporter. J Bioenerg Biomembr 1995; 27:15-22. [PMID: 7629046 DOI: 10.1007/bf02110326] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
P-Glycoprotein, the multidrug transporter, is isolated from the plasma membrane of CHRC5 cells using a selective two-step detergent extraction procedure. The partially purified protein displays a high level of ATPase activity, which has a high KM for ATP, is stimulated by drugs, and can be distinguished from that of other membrane ATPases by its unique inhibition profile. Delipidation completely inactivates ATPase activity, which is restored by the addition of fluid lipid mixtures. P-Glycoprotein was reconstituted into lipid bilayers with retention of both drug transport and ATPase activity. Proteoliposomes containing P-glycoprotein display osmotically sensitive ATP-dependent accumulation of 3H-colchicine in the vesicle lumen. Drug transport is active, generating a stable 5.6-fold concentration gradient, and can be blocked by compounds in the multidrug resistance spectrum. Reconstituted P-glycoprotein also exhibits a high level of ATPase activity which is further stimulated by various drugs. P-Glycoprotein therefore functions as an active drug transporter with constitutive ATPase activity.
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Affiliation(s)
- F J Sharom
- Guelph-Waterloo Centre for Graduate Work in Chemistry, Department of Chemistry and Biochemistry, University of Guelph, Ontario, Canada
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Loe DW, Sharom FJ. Interaction of multidrug-resistant Chinese hamster ovary cells with the peptide ionophore gramicidin D. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1190:72-84. [PMID: 7509193 DOI: 10.1016/0005-2736(94)90035-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A major form of multidrug resistance results from the overexpression of P-glycoprotein, a 170 kDa membrane protein. Multidrug resistant (MDR) Chinese hamster ovary (CHO) cells and mdrl transfectants displayed cross-resistance to the channel-forming peptide ionophore gramicidin D, which was reversed by various chemosensitizers, thus directly implicating P-glycoprotein as the mediator of resistance. However, gramicidin D was not able to inhibit [3H]azidopine photolabelling of P-glycoprotein. MDR cells were not resistant to other pore-forming ionophores, but showed a modest level of cross-resistance to the mobile ionophore valinomycin. There was no difference in 125I-gramicidin D uptake by resistant and sensitive cells. Resistant cells showed lower 86Rb+ uptake, relative to the drug-sensitive parent. Addition of GmD increased both the rate and the level of 86Rb+ uptake in sensitive cells, but had no effect on MDR cells. MDR cells also showed much lower rates of gramicidin D-dependent 86Rb+ efflux than sensitive cells, and this was greatly increased by verapamil. These results suggest that P-glycoprotein interferes with the formation of ion-conducting gramicidin D channels. In contrast, valinomycin had the same effect on gramicidin D-dependent cation efflux in MDR and sensitive cells. Gramicidin D is thus unique among the ionophores is being a substrate for P-glycoprotein, which appears to greatly reduce the formation of active dimeric channels in the plasma membrane of MDR cells.
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Affiliation(s)
- D W Loe
- Guelph-Waterloo Centre for Graduate Work in Chemistry, Department of Chemistry and Biochemistry, University of Guelph, Ontario, Canada
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Functional reconstitution of drug transport and ATPase activity in proteoliposomes containing partially purified P-glycoprotein. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(20)80510-9] [Citation(s) in RCA: 194] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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