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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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Tran NNB, Bui ATA, Jaramillo-Martinez V, Weber J, Zhang Q, Urbatsch IL. Lipid environment determines the drug-stimulated ATPase activity of P-glycoprotein. Front Mol Biosci 2023; 10:1141081. [PMID: 36911528 PMCID: PMC9995911 DOI: 10.3389/fmolb.2023.1141081] [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: 01/09/2023] [Accepted: 02/06/2023] [Indexed: 02/25/2023] Open
Abstract
P-glycoprotein (Pgp) is a multidrug transporter that uses the energy from ATP binding and hydrolysis to export from cells a wide variety of hydrophobic compounds including anticancer drugs, and mediates the bioavailability and pharmacokinetics of many drugs. Lipids and cholesterol have been shown to modulate the substrate-stimulated ATPase activity of purified Pgp in detergent solution and the substrate transport activity after reconstitution into proteoliposomes. While lipid extracts from E. coli, liver or brain tissues generally support well Pgp's functionality, their ill-defined composition and high UV absorbance make them less suitable for optical biophysical assays. On the other hand, studies with defined synthetic lipids, usually the bilayer-forming phosphatidylcholine with or without cholesterol, are often plagued by low ATPase activity and low binding affinity of Pgp for drugs. Drawing from the lipid composition of mammalian plasma membranes, we here investigate how different head groups modulate the verapamil-stimulated ATPase activity of purified Pgp in detergent-lipid micelles and compare them with components of E. coli lipids. Our general approach was to assay modulation of verapamil-stimulation of ATPase activity by artificial lipid mixtures starting with the bilayer-forming palmitoyloyl-phosphatidylcholine (POPC) and -phosphatidylethanolamine (POPE). We show that POPC/POPE supplemented with sphingomyelin (SM), cardiolipin, or phosphatidic acid enhanced the verapamil-stimulated activity (Vmax) and decreased the concentration required for half-maximal activity (EC50). Cholesterol (Chol) and more so its soluble hemisuccinate derivative cholesteryl hemisuccinate substantially decreased EC50, perhaps by supporting the functional integrity of the drug binding sites. High concentrations of CHS (>15%) resulted in a significantly increased basal activity which could be due to binding of CHS to the drug binding site as transport substrate or as activator, maybe acting cooperatively with verapamil. Lastly, Pgp reconstituted into liposomes or nanodiscs displayed higher basal activity and sustained high levels of verapamil stimulated activity. The findings establish a stable source of artificial lipid mixtures containing either SM and cholesterol or CHS that restore Pgp functionality with activities and affinities similar to those in the natural plasma membrane environment and will pave the way for future functional and biophysical studies.
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Affiliation(s)
- Nghi N. B. Tran
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, United States
- Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - A. T. A. Bui
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, United States
- Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Valeria Jaramillo-Martinez
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, United States
- Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Joachim Weber
- Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, United States
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, United States
| | - Qinghai Zhang
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, United States
| | - Ina L. Urbatsch
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, United States
- Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, United States
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Omics Analysis of Chemoresistant Triple Negative Breast Cancer Cells Reveals Novel Metabolic Vulnerabilities. Cells 2022; 11:cells11172719. [PMID: 36078127 PMCID: PMC9454761 DOI: 10.3390/cells11172719] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/23/2022] [Accepted: 08/25/2022] [Indexed: 11/16/2022] Open
Abstract
The emergence of drug resistance in cancer poses the greatest hurdle for successful therapeutic results and is associated with most cancer deaths. In triple negative breast cancer (TNBC), due to the lack of specific therapeutic targets, systemic chemotherapy is at the forefront of treatments, but it only benefits a fraction of patients because of the development of resistance. Cancer cells may possess an innate resistance to chemotherapeutic agents or develop new mechanisms of acquired resistance after long-term drug exposure. Such mechanisms involve an interplay between genetic, epigenetic and metabolic alterations that enable cancer cells to evade therapy. In this work, we generated and characterized a chemoresistant TNBC cell line to be used for the investigation of mechanisms that drive resistance to paclitaxel. Transcriptomic analysis highlighted the important role of metabolic-associated pathways in the resistant cells, prompting us to employ 1H-NMR to explore the metabolome and lipidome of these cells. We identified and described herein numerous metabolites and lipids that were significantly altered in the resistant cells. Integrated analysis of our omics data revealed MSMO1, an intermediate enzyme of cholesterol biosynthesis, as a novel mediator of chemoresistance in TNBC. Overall, our data provide a critical insight into the metabolic adaptations that accompany acquired resistance in TNBC and pinpoint potential new targets.
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Zhang N, Gao M, Wang Z, Zhang J, Cui W, Li J, Zhu X, Zhang H, Yang DH, Xu X. Curcumin reverses doxorubicin resistance in colon cancer cells at the metabolic level. J Pharm Biomed Anal 2021; 201:114129. [PMID: 34000577 DOI: 10.1016/j.jpba.2021.114129] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 12/11/2022]
Abstract
Doxorubicin (Dox) is commonly used for the treatment of malignant tumors, including colon cancer. However, the development of P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) in tumor chemotherapy has seriously reduced the therapeutic efficacy of Dox. Natural product curcumin (Cur) was demonstrated to have a variety of pharmacological effects, such as anti-tumor, anti-oxidation and anti-aging activities. Here, we examined the MDR reversal capability of Cur in drug sensitive-(SW620) and resistant-(SW620/Ad300) colon cancer cells, and elucidated the underlying molecular mechanisms at the metabolic level. It was found that Cur reversed P-gp-mediated resistance in SW620/Ad300 cells by enhancing the Dox-induced cytotoxicity and apoptosis. Further mechanistic studies indicated that Cur inhibited the ATP-dependent transport activity of P-gp, thereby increasing the intra-celluar accumulation of Dox in drug-resistant cells. Metabolomics analysis based on UPLC-MS/MS showed that the MDR phenomenon in SW620/Ad300 cells was closely correlated with the upregulation of spermine and spermidine synthesis and D-glutamine metabolism. Cur significantly inhibited the biosynthesis of spermine and spermidine by decreasing the expression of ornithine decarboxylase (ODC) and suppressed D-glutamine metabolism, which in turn decreased the anti-oxidative stress ability and P-gp transport activity of SW620/Ad300 cells, eventually reversed MDR. These findings indicated the MDR reversal activity and the related mechanism of action of Cur, suggesting that Cur could be a promising MDR reversal agent for cancer treatment.
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Affiliation(s)
- Nan Zhang
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan, 450001, China
| | - Ming Gao
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan, 450001, China
| | - Zihan Wang
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan, 450001, China
| | - Jingxian Zhang
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan, 450001, China
| | - Weiqi Cui
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan, 450001, China
| | - Jinjin Li
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan, 450001, China
| | - Xiaolin Zhu
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan, 450001, China
| | - Hang Zhang
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan, 450001, China.
| | - Dong-Hua Yang
- College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, NY, 11439, Jamaica.
| | - Xia Xu
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan, 450001, China.
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5
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Szlasa W, Zendran I, Zalesińska A, Tarek M, Kulbacka J. Lipid composition of the cancer cell membrane. J Bioenerg Biomembr 2020; 52:321-342. [PMID: 32715369 PMCID: PMC7520422 DOI: 10.1007/s10863-020-09846-4] [Citation(s) in RCA: 177] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/10/2020] [Indexed: 12/12/2022]
Abstract
Cancer cell possesses numerous adaptations to resist the immune system response and chemotherapy. One of the most significant properties of the neoplastic cells is the altered lipid metabolism, and consequently, the abnormal cell membrane composition. Like in the case of phosphatidylcholine, these changes result in the modulation of certain enzymes and accumulation of energetic material, which could be used for a higher proliferation rate. The changes are so prominent, that some lipids, such as phosphatidylserines, could even be considered as the cancer biomarkers. Additionally, some changes of biophysical properties of cell membranes lead to the higher resistance to chemotherapy, and finally to the disturbances in signalling pathways. Namely, the increased levels of certain lipids, like for instance phosphatidylserine, lead to the attenuation of the immune system response. Also, changes in lipid saturation prevent the cells from demanding conditions of the microenvironment. Particularly interesting is the significance of cell membrane cholesterol content in the modulation of metastasis. This review paper discusses the roles of each lipid type in cancer physiology. The review combined theoretical data with clinical studies to show novel therapeutic options concerning the modulation of cell membranes in oncology.
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Affiliation(s)
- Wojciech Szlasa
- Faculty of Medicine, Wroclaw Medical University, Wrocław, Poland
| | - Iga Zendran
- Faculty of Medicine, Wroclaw Medical University, Wrocław, Poland
| | | | - Mounir Tarek
- Université de Lorraine, CNRS, LPCT, F-54000, Nancy, France
| | - Julita Kulbacka
- Department of Molecular and Cellular Biology, Faculty of Pharmacy, Wroclaw Medical University, Wrocław, Poland.
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Carey Hulyer AR, Briggs DA, O'Mara ML, Kerr ID, Harmer JR, Callaghan R. Cross-linking, DEER-spectroscopy and molecular dynamics confirm the inward facing state of P-glycoprotein in a lipid membrane. J Struct Biol 2020; 211:107513. [PMID: 32339763 DOI: 10.1016/j.jsb.2020.107513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 04/09/2020] [Accepted: 04/23/2020] [Indexed: 02/07/2023]
Abstract
The drug efflux pump P-glycoprotein (P-gp) displays a complex transport mechanism involving multiple drug binding sites and two centres for nucleotide hydrolysis. Elucidating the molecular mechanism of transport remains elusive and the availability of P-gp structures in distinct natural and ligand trapped conformations will accelerate our understanding. The present investigation sought to provide biochemical data to validate specific features of these structures; with particular focus on the transmembrane domain that provides the transport conduit. Hence our focus was on transmembrane helices six and twelve (TM6/TM12), which are believed to participate in drug binding, as they line the central transport conduit and provide a direct link to the catalytic centres. A series of P-gp mutants were generated with a single cysteine in both TM6 and TM12 to facilitate measurement of inter-helical distances using cross-linking and DEER strategies. Experimental results were compared to published structures per se and those refined by MD simulations. This analysis revealed that the refined inward-facing murine structure (4M1M) of P-gp provides a good representation of the proximity, topography and relative motions of TM6 and TM12 in reconstituted human P-gp.
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Affiliation(s)
- Alex R Carey Hulyer
- Research School of Biology, and the Medical School, Australian National University, Canberra, ACT 2601, Australia
| | - Deborah A Briggs
- Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Megan L O'Mara
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Ian D Kerr
- Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Jeffrey R Harmer
- The Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Richard Callaghan
- Research School of Biology, and the Medical School, Australian National University, Canberra, ACT 2601, Australia.
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7
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Trombik P, Cieślik-Boczula K. Influence of phenothiazine molecules on the interactions between positively charged poly-l-lysine and negatively charged DPPC/DPPG membranes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 227:117563. [PMID: 31689607 DOI: 10.1016/j.saa.2019.117563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 09/20/2019] [Accepted: 09/21/2019] [Indexed: 06/10/2023]
Abstract
Phenothiazines are very effective antipsychotic drugs, which also have anticancer and antimicrobial activities. Despite being used in human treatment, the molecular mechanism of the biological actions of these molecules is not yet understood in detail. The role of the interactions between phenothiazines and proteins or lipid membranes has been much discussed. Herein, fourier-transform infrared (FTIR) spectroscopic studies were used to investigate the effect of three phenothiazines: fluphenazine (FPh); chlorpromazine (ChP); and propionylpromazine (PP) on the structures of a positively charged poly-l-lysine (PLL) peptide, a negatively charged dipalmitoylphosphatidylcholine/dipalmitoylphosphatidylglycerol (DPPC/DPPG) membrane, and on the mutual interactions between electrostatically associated PLL molecules and DPPC/DPPG membranes. Phenothiazine-induced alterations in the secondary structure of PLL, the conformational state (trans/gauche) of the hydrocarbon lipid chains, and the hydration of the DPPC/DPPG membrane interface were studied on the basis of amide I' vibrations, antisymmetric and symmetric stretching vibrations of the CH2 groups of the lipid hydrocarbon chains (νsCH2), and stretching vibrations of the lipid C=O groups (νC = O), respectively. It was shown that in the presence of negatively charged DPPC/DPPG membranes, the phenothiazines were able to modify the secondary structure of charged PLL molecules. Additionally, the effect of PLL on the structure of DPPC/DPPG membranes was also altered by the presence of the phenothiazine molecules.
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Affiliation(s)
- Paulina Trombik
- Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50-383, Wroclaw, Poland
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Schumann-Gillett A, Blyth MT, O’Mara ML. Is protein structure enough? A review of the role of lipids in SLC6 transporter function. Neurosci Lett 2019; 700:64-69. [DOI: 10.1016/j.neulet.2018.05.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 05/09/2018] [Accepted: 05/11/2018] [Indexed: 12/17/2022]
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Santos FC, Lobo GM, Fernandes AS, Videira A, de Almeida RFM. Changes in the Biophysical Properties of the Cell Membrane Are Involved in the Response of Neurospora crassa to Staurosporine. Front Physiol 2018; 9:1375. [PMID: 30364194 PMCID: PMC6193110 DOI: 10.3389/fphys.2018.01375] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/11/2018] [Indexed: 01/27/2023] Open
Abstract
Neurospora crassa is a non-pathogenic filamentous fungus widely used as a multicellular eukaryotic model. Recently, the biophysical properties of the plasma membrane of N. crassa conidia were thoroughly characterized. They evolve during conidial germination at a speed that depends on culture conditions, suggesting an important association between membrane remodeling and the intense membrane biogenesis that takes place during the germinative process. Staurosporine (STS) is a drug used to induce programmed cell death in various organisms. In N. crassa, STS up-regulates the expression of the ABC transporter ABC-3, which localizes at the plasma membrane and pumps STS out. To understand the role of plasma membrane biophysical properties in the fungal drug response, N. crassa was subjected to STS treatment during early and late conidial development stages. Following 1 h treatment with STS, there is an increase in the abundance of the more ordered, sphingolipid-enriched, domains in the plasma membrane of conidia. This leads to higher fluidity in other membrane regions. The global order of the membrane remains thus practically unchanged. Significant changes in sphingolipid-enriched domains were also observed after 15 min challenge with STS, but they were essentially opposite to those verified for the 1 h treatment, suggesting different types of drug responses. STS effects on membrane properties that are more dependent on ergosterol levels also depend on the developmental stage. There were no alterations on 2 h-grown cells, clearly contrasting to what happens at longer growth times. In this case, the differences were more marked for longer STS treatment, and rationalized considering that the drug prevents the increase in the ergosterol/glycerophospholipid ratio that normally takes place at the late conidial stage/transition to the mycelial stage. This could be perceived as a drug-induced development arrest after 5 h growth, involving ergosterol, and pointing to a role of lipid rafts possibly related with an up-regulated expression of the ABC-3 transporter. Overall, our results suggest the involvement of membrane ordered domains in the response mechanisms to STS in N. crassa.
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Affiliation(s)
- Filipa C Santos
- Departamento de Química e Bioquímica, Faculdade de Ciências, Centro de Química e Bioquímica, Universidade de Lisbon, Campo Grande, Lisbon, Portugal
| | - Gerson M Lobo
- Departamento de Química e Bioquímica, Faculdade de Ciências, Centro de Química e Bioquímica, Universidade de Lisbon, Campo Grande, Lisbon, Portugal
| | - Andreia S Fernandes
- I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Arnaldo Videira
- I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,ICBAS-Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Rodrigo F M de Almeida
- Departamento de Química e Bioquímica, Faculdade de Ciências, Centro de Química e Bioquímica, Universidade de Lisbon, Campo Grande, Lisbon, Portugal
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Park S, Majd S. Reconstitution and functional studies of hamster P-glycoprotein in giant liposomes. PLoS One 2018; 13:e0199279. [PMID: 29912971 PMCID: PMC6005519 DOI: 10.1371/journal.pone.0199279] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 06/05/2018] [Indexed: 11/18/2022] Open
Abstract
This paper describes the preparation of giant unilamellar vesicles with reconstituted hamster P-glycoprotein (Pgp, ABCB1) for studying the transport activity of this efflux pump in individual liposomes using optical microscopy. Pgp, a member of ABC (ATP-binding cassette) transporter family, is known to contribute to the cellular multidrug resistance (MDR) against variety of drugs. The efficacy of many therapeutics is, thus, hampered by this efflux pump, leading to a high demand for simple and effective strategies to monitor the interactions of candidate drugs with this protein. Here, we applied small Pgp proteoliposomes to prepare giant Pgp-bearing liposomes via modified electroformation techniques. The presence of Pgp in the membrane of giant proteoliposomes was confirmed using immunohistochemistry. Assessment of Pgp ATPase activity suggested that this transporter retained its activity upon reconstitution into giant liposomes, with an ATPase specific activity of 439 ± 103 nmol/mg protein/min. For further confirmation, we assessed the transport activity of Pgp in these proteoliposomes by monitoring the translocation of rhodamine 123 (Rho123) across the membrane using confocal microscopy at various ATP concentrations (0-2 mM) and in the presence of Pgp inhibitors. Rate of change in Rho123 concentration inside the liposomal lumen was used to estimate the Rho123 transport rates (1/s) for various ATP concentrations, which were then applied to retrieve the Michaelis-Menten constant (Km) of ATP in Rho123 transport (0.42 ± 0.75 mM). Similarly, inhibitory effects of verapamil, colchicine, and cyclosporin A on Pgp were studied in this system and the IC50 values for these Pgp inhibitors were found 26.6 ± 6.1 μM, 94.6 ± 47.6 μM, and 0.21 ± 0.07 μM, respectively. We further analyzed the transport data using a kinetic model that enabled dissecting the passive diffusion of Rho123 from its Pgp-mediated transport across the membrane. Based on this model, the permeability coefficient of Rho123 across the liposomal membrane was approximately 1.25×10-7 cm/s. Comparing the membrane permeability in liposomes with and without Pgp revealed that the presence of this protein did not have a significant impact on membrane integrity and permeability. Furthermore, we used this model to obtain transport rate constants for the Pgp-mediated transport of Rho123 (m3/mol/s) at various ATP and inhibitor concentrations, which were then applied to estimate values of 0.53 ± 0.66 mM for Km of ATP and 25.2 ± 5.0 μM for verapamil IC50, 61.8 ± 34.8 μM for colchicine IC50, and 0.23 ± 0.09 μM for cyclosporin A IC50. The kinetic parameters obtained from the two analyses were comparable, suggesting a minimal contribution from the passive Rho123 diffusion across the membrane. This approach may, therefore, be applied for screening the transport activity of Pgp against potential drug candidates.
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Affiliation(s)
- SooHyun Park
- The Brown Foundation Institute of Molecular Medicine and Texas Therapeutics Institute, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Sheereen Majd
- Department of Biomedical Engineering, University of Houston, Houston, Texas, United States of America
- * E-mail:
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11
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Alves AC, Ribeiro D, Horta M, Lima JLFC, Nunes C, Reis S. A biophysical approach to daunorubicin interaction with model membranes: relevance for the drug's biological activity. J R Soc Interface 2018; 14:rsif.2017.0408. [PMID: 28855387 DOI: 10.1098/rsif.2017.0408] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/04/2017] [Indexed: 01/10/2023] Open
Abstract
Daunorubicin is extensively used in chemotherapy for diverse types of cancer. Over the years, evidence has suggested that the mechanisms by which daunorubicin causes cytotoxic effects are also associated with interactions at the membrane level. The aim of the present work was to study the interplay between daunorubicin and mimetic membrane models composed of different ratios of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), sphingomyelin (SM) and cholesterol (Chol). Several biophysical parameters were assessed using liposomes as mimetic model membranes. Thereby, the ability of daunorubicin to partition into lipid bilayers, its apparent location within the membrane and its effect on membrane fluidity were investigated. The results showed that daunorubicin has higher affinity for lipid bilayers composed of DMPC, followed by DMPC : SM, DMPC : Chol and lastly by DMPC : SM : Chol. The addition of SM or Chol into DMPC membranes not only increases the complexity of the model membrane but also decreases its fluidity, which, in turn, reduces the amount of anticancer drug that can partition into these mimetic models. Fluorescence quenching studies suggest a broad distribution of the drug across the bilayer thickness, with a preferential location in the phospholipid tails. The gathered data support that daunorubicin permeates all types of membranes to different degrees, interacts with phospholipids through electrostatic and hydrophobic bonds and causes alterations in the biophysical properties of the bilayers, namely in membrane fluidity. In fact, a decrease in membrane fluidity can be observed in the acyl region of the phospholipids. Ultimately, such outcomes can be correlated with daunorubicin's biological action, where membrane structure and lipid composition have an important role. In fact, the results indicate that the intercalation of daunorubicin between the phospholipids can also take place in rigid domains, such as rafts that are known to be involved in different receptor processes, which are important for cellular function.
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Affiliation(s)
- Ana Catarina Alves
- UCIBIO, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal
| | - Daniela Ribeiro
- UCIBIO, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal
| | - Miguel Horta
- UCIBIO, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal
| | - José L F C Lima
- UCIBIO, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal
| | - Cláudia Nunes
- UCIBIO, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal
| | - Salette Reis
- UCIBIO, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal
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12
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Influence of doxorubicin on model cell membrane properties: insights from in vitro and in silico studies. Sci Rep 2017; 7:6343. [PMID: 28740256 PMCID: PMC5524714 DOI: 10.1038/s41598-017-06445-z] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 06/13/2017] [Indexed: 01/31/2023] Open
Abstract
Despite doxorubicin being commonly used in chemotherapy there still remain significant holes in our knowledge regarding its delivery efficacy and an observed resistance mechanism that is postulated to involve the cell membrane. One possible mechanism is the efflux by protein P-gp, which is found predominantly in cholesterol enriched domains. Thereby, a hypothesis for the vulnerability of doxorubicin to efflux through P-gp is its enhanced affinity for the ordered cholesterol rich regions of the plasma membrane. Thus, we have studied doxorubicin’s interaction with model membranes in a cholesterol rich, ordered environment and in liquid-disordered cholesterol poor environment. We have combined three separate experimental protocols: UV-Vis spectrophotometry, fluorescence quenching and steady-state anisotropy and computational molecular dynamics modeling. Our results show that the presence of cholesterol induces a change in membrane structure and doesn’t impair doxorubicin’s membrane partitioning, but reduces drug’s influence on membrane fluidity without directly interacting with it. It is thus possible that the resistance mechanism that lowers the efficacy of doxorubicin, results from an increased density in membrane regions where the efflux proteins are present. This work represents a successful approach, combining experimental and computational studies of membrane based systems to unveil the behavior of drugs and candidate drug molecules.
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13
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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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14
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Ferreira RJ, Bonito CA, Ferreira MJU, dos Santos DJ. About P-glycoprotein: a new drugable domain is emerging from structural data. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2017. [DOI: 10.1002/wcms.1316] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Ricardo J. Ferreira
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy; Universidade de Lisboa; Lisboa Portugal
| | - Cátia A. Bonito
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy; Universidade de Lisboa; Lisboa Portugal
- LAQV@REQUIMTE/Department of Chemistry and Biochemistry, Faculty of Sciences; University of Porto; Porto Portugal
| | - Maria José U. Ferreira
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy; Universidade de Lisboa; Lisboa Portugal
| | - Daniel J.V.A. dos Santos
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy; Universidade de Lisboa; Lisboa Portugal
- LAQV@REQUIMTE/Department of Chemistry and Biochemistry, Faculty of Sciences; University of Porto; Porto Portugal
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15
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Biophysics in cancer: The relevance of drug-membrane interaction studies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2231-2244. [DOI: 10.1016/j.bbamem.2016.06.025] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/31/2016] [Accepted: 06/26/2016] [Indexed: 12/26/2022]
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16
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Subramanian N, Condic-Jurkic K, O'Mara ML. Structural and dynamic perspectives on the promiscuous transport activity of P-glycoprotein. Neurochem Int 2016; 98:146-52. [PMID: 27180050 DOI: 10.1016/j.neuint.2016.05.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 04/28/2016] [Accepted: 05/03/2016] [Indexed: 11/25/2022]
Abstract
The multidrug transporter P-glycoprotein (P-gp) is expressed in the blood-brain barrier endothelium where it effluxes a range of drug substrates, preventing their accumulation within the brain. P-gp has been studied extensively for 40 years because of its crucial role in the absorption, distribution, metabolism and elimination of a range of pharmaceutical compounds. Despite this, many aspects of the structure-function mechanism of P-gp are unresolved. Here we review the emerging role of molecular dynamics simulation techniques in our understanding of the membrane-embedded conformation of P-gp. We discuss its conformational plasticity in the presence and absence of ATP, and recent efforts to characterize the drug binding sites and uptake pathways.
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Affiliation(s)
- Nandhitha Subramanian
- Research School of Chemistry (RSC), The Australian National University, Canberra, ACT, 2601, Australia
| | - Karmen Condic-Jurkic
- School of Chemistry and Molecular Biosciences (SCMB), University of Queensland, Brisbane, QLD, 4072, Australia
| | - Megan L O'Mara
- Research School of Chemistry (RSC), The Australian National University, Canberra, ACT, 2601, Australia. megan.o'
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17
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Subramanian N, Schumann-Gillett A, Mark AE, O'Mara ML. Understanding the accumulation of P-glycoprotein substrates within cells: The effect of cholesterol on membrane partitioning. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:776-82. [DOI: 10.1016/j.bbamem.2015.12.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 11/18/2015] [Accepted: 12/21/2015] [Indexed: 11/25/2022]
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18
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Emerging Role of miRNAs in the Drug Resistance of Gastric Cancer. Int J Mol Sci 2016; 17:424. [PMID: 27011182 PMCID: PMC4813275 DOI: 10.3390/ijms17030424] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/11/2016] [Accepted: 03/16/2016] [Indexed: 12/15/2022] Open
Abstract
Gastric cancer is the third leading cause of cancer mortality worldwide. Unfortunately, most gastric cancer cases are diagnosed in an advanced, non-curable stage and with a limited response to chemotherapy. Drug resistance is one of the most important causes of therapy failure in gastric cancer patients. Although the mechanisms of drug resistance have been broadly studied, the regulation of these mechanisms has not been completely understood. Accumulating evidence has recently highlighted the role of microRNAs in the development and maintenance of drug resistance due to their regulatory features in specific genes involved in the chemoresistant phenotype of malignancies, including gastric cancer. This review summarizes the current knowledge about the miRNAs’ characteristics, their regulation of the genes involved in chemoresistance and their potential as targeted therapies for personalized treatment in resistant gastric cancer.
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19
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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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20
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Ferreira RJ, Ferreira MJU, dos Santos DJVA. Do adsorbed drugs onto P-glycoprotein influence its efflux capability? Phys Chem Chem Phys 2015; 17:22023-34. [PMID: 26235302 DOI: 10.1039/c5cp03216d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The membrane biophysical aspects by which multidrug resistance (MDR) relate to the ABC transporter function still remain largely unknown. Notwithstanding the central role that efflux pumps like P-glycoprotein have in MDR onset, experimental studies classified additionally the lipid micro-environment where P-gp is inserted as a determinant for the increased efflux capability demonstrated in MDR cell lines. Recently, a nonlinear model for drug-membrane interactions showed that, upon drug adsorption, long-range mechanical alterations are predicted to affect the P-gp ATPase function at external drug concentrations of ∼10-100 μM. However, our results also show that drug adsorption may also occur at P-gp nucleotide-binding domains where conformational changes drive the efflux cycle. Thus, we assessed the effect of drug adsorption to both protein-water and lipid-water interfaces by means of molecular dynamics simulations. The results show that free energies of adsorption are lower for modulators in both lipid/water and protein/water interfaces. Important differences in drug-protein interactions, protein dynamics and membrane biophysical characteristics were observed between the different classes. Therefore, we hypothesize that drug adsorption to the protein and lipid-water interface accounts for a complex network of events that affect the ability of transporters to efflux drugs.
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Affiliation(s)
- Ricardo J Ferreira
- Research Institute for Medicines (iMed.Ulisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisboa, Portugal.
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21
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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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22
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Zhang Y, Qu X, Teng Y, Li Z, Xu L, Liu J, Ma Y, Fan Y, Li C, Liu S, Wang Z, Hu X, Zhang J, Liu Y. Cbl-b inhibits P-gp transporter function by preventing its translocation into caveolae in multiple drug-resistant gastric and breast cancers. Oncotarget 2015; 6:6737-48. [PMID: 25788263 PMCID: PMC4466646 DOI: 10.18632/oncotarget.3253] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 01/29/2015] [Indexed: 12/25/2022] Open
Abstract
The transport function of P-glycoprotein (P-gp) requires its efficient localization to caveolae, a subset of lipid rafts, and disruption of caveolae suppresses P-gp transport function. However, the regulatory molecules involved in the translocation of P-gp into caveolae remain unknown. In the present study, we showed that c-Src dependent Caveolin-1 phosphorylation promoted the translocation of P-gp into caveolae, resulting in multidrug resistance in adriamycin resistant gastric cancer SGC7901/Adr and breast cancer MCF-7/Adr cells. In a negative feedback loop, the translocation of Cbl-b from the nucleus to the cytoplasm prevented the localization of P-gp to caveolae resulting in the reversal of MDR through the ubiquitination and degradation of c-Src. Clinical data showed a significant positive relationship between Cbl-b expression and survival in P-gp positive breast cancer patients who received anthracycline-based chemotherapy. Our findings identified a new regulatory mechanism of P-gp transport function in multiple drug-resistant gastric and breast cancers.
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Affiliation(s)
- Ye Zhang
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Xiujuan Qu
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Yuee Teng
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Zhi Li
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Ling Xu
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Jing Liu
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Yanju Ma
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Yibo Fan
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Ce Li
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Shizhou Liu
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Zhenning Wang
- 2 Department of Surgical Oncology and General Surgery, the First Hospital of China Medical University, Shenyang 110001, China
| | - Xuejun Hu
- 3 Department of Medical Respiratory, the First Hospital of China Medical University, Shenyang 110001, China
| | - Jingdong Zhang
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Yunpeng Liu
- 1 Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
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23
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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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24
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Gomà A, Mir R, Martínez-Soler F, Tortosa A, Vidal A, Condom E, Pérez-Tomás R, Giménez-Bonafé P. Multidrug resistance protein 1 localization in lipid raft domains and prostasomes in prostate cancer cell lines. Onco Targets Ther 2014; 7:2215-25. [PMID: 25525371 PMCID: PMC4266421 DOI: 10.2147/ott.s69530] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND One of the problems in prostate cancer (CaP) treatment is the appearance of the multidrug resistance phenotype, in which ATP-binding cassette transporters such as multidrug resistance protein 1 (MRP1) play a role. Different localizations of the transporter have been reported, some of them related to the chemoresistant phenotype. AIM This study aimed to compare the localization of MRP1 in three prostate cell lines (normal, androgen-sensitive, and androgen-independent) in order to understand its possible role in CaP chemoresistance. METHODS MRP1 and caveolae protein markers were detected using confocal microscopy, performing colocalization techniques. Lipid raft isolation made it possible to detect these proteins by Western blot analysis. Caveolae and prostasomes were identified by electron microscopy. RESULTS We show that MRP1 is found in lipid raft fractions of tumor cells and that the number of caveolae increases with malignancy acquisition. MRP1 is found not only in the plasma membrane associated with lipid rafts but also in cytoplasmic accumulations colocalizing with the prostasome markers Caveolin-1 and CD59, suggesting that in CaP cells, MRP1 is localized in prostasomes. CONCLUSION We hypothesize that the presence of MRP1 in prostasomes could serve as a reservoir of MRP1; thus, taking advantage of the release of their content, MRP1 could be translocated to the plasma membrane contributing to the chemoresistant phenotype. The presence of MRP1 in prostasomes could serve as a predictor of malignancy in CaP.
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Affiliation(s)
- Alba Gomà
- Departament de Ciències Fisiològiques II, Faculty of Medicine, Campus of Health Sciences of Bellvitge, Universitat de Barcelona, IDIBELL, Barcelona, Spain
| | - Roser Mir
- Departament de Ciències Fisiològiques II, Faculty of Medicine, Campus of Health Sciences of Bellvitge, Universitat de Barcelona, IDIBELL, Barcelona, Spain ; División de Investigación Básica, Instituto Nacional de Cancerología, México DF, Mexico ; Instituto de Física, Universidad Nacional Autónoma de México (UNAM), México DF, Mexico
| | - Fina Martínez-Soler
- Departament de Ciències Fisiològiques II, Faculty of Medicine, Campus of Health Sciences of Bellvitge, Universitat de Barcelona, IDIBELL, Barcelona, Spain ; Department of Basic Nursing, School of Nursing of the Health Campus of Bellvitge, Universitat de Barcelona, Spain
| | - Avelina Tortosa
- Department of Basic Nursing, School of Nursing of the Health Campus of Bellvitge, Universitat de Barcelona, Spain
| | - August Vidal
- Department of Pathology, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain ; Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, IDIBELL, Barcelona, Spain
| | - Enric Condom
- Department of Pathology, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain ; Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, IDIBELL, Barcelona, Spain
| | - Ricardo Pérez-Tomás
- Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, IDIBELL, Barcelona, Spain
| | - Pepita Giménez-Bonafé
- Departament de Ciències Fisiològiques II, Faculty of Medicine, Campus of Health Sciences of Bellvitge, Universitat de Barcelona, IDIBELL, Barcelona, Spain
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25
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Zhang Y, Qu X, Li C, Fan Y, Che X, Wang X, Cai Y, Hu X, Liu Y. miR-103/107 modulates multidrug resistance in human gastric carcinoma by downregulating Cav-1. Tumour Biol 2014; 36:2277-85. [PMID: 25407491 DOI: 10.1007/s13277-014-2835-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 11/10/2014] [Indexed: 12/24/2022] Open
Abstract
MicroRNAs (miRNAs) are a class of non-protein-coding small RNAs with the capacity to regulate fundamental biological processes essential for cancer initiation and progression. In the present study, we analyzed miRNA expression levels between multidrug-resistant gastric carcinoma cell line SGC7901/ADR and its parent cell line SGC7901 using a miRNA microarray. MiR-103/107 was downregulated compared with parental SGC7901 cells. Overexpression of miR-103/107 sensitized SGC7901/ADR cells to doxorubicin (DOX), as demonstrated by in vitro and in vivo drug sensitivity assay. We further confirmed that miR-103/107 inhibited P-gp function in gastric cancer SGC7901/ADR cells. Finally, we verified that caveolin-1 (Cav-1), a critical component of lipid rafts, was a target of miR-103/107.
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Affiliation(s)
- Ye Zhang
- Department of Medical Oncology, The First Hospital of China Medical University, NO. 155, North Nanjing Street, Heping District, Shenyang, 110001, China
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26
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van Wonderen JH, McMahon RM, O'Mara ML, McDevitt CA, Thomson AJ, Kerr ID, MacMillan F, Callaghan R. The central cavity of ABCB1 undergoes alternating access during ATP hydrolysis. FEBS J 2014; 281:2190-2201. [PMID: 24597976 PMCID: PMC4892341 DOI: 10.1111/febs.12773] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 02/18/2014] [Accepted: 02/28/2014] [Indexed: 02/06/2023]
Abstract
Understanding the process that underlies multidrug recognition and efflux by P-glycoprotein (ABCB1) remains a key biological challenge. Structural data have recently become available for the murine and Caenorhabditis elegans homologues of ABCB1; however all structures were obtained in the absence of nucleotide. A feature of these structures was the presence of a central cavity that is inaccessible from the extracellular face of the protein. To determine the conformational dynamics of this region several residues in transmembrane helices TM6 (331, 343 and 354) and TM12 (980) were mutated to cysteine. Based upon structural predictions, these residues are proposed to line, or reside proximal to, the central cavity. The mutant isoforms were labelled with a paramagnetic probe enabling the application of EPR spectroscopic methods. Power saturation EPR spectra were recorded in the presence of hydrophobic (O2 ) or hydrophilic (NiEDDA) quenching agents to study the local environment of each residue. ABCB1 was trapped in both its nucleotide-bound and post-hydrolytic conformations and EPR spectra were again recorded in the presence and absence of quenching agents. The EPR line shapes provide information on the movements of these residues within TM6 and TM12 during ATP hydrolysis. Rationalization of the data with molecular dynamic simulations indicates that the cavity is converted to a configuration open to the aqueous phase following nucleotide binding, thereby suggesting alternating access to the cavity on opposite sides of the membrane during translocation.
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Affiliation(s)
- Jessica H. van Wonderen
- Henry Wellcome Unit for Biological EPR, School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK
| | - Róisin M. McMahon
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
- Institute for Molecular Bioscience, Chemistry and Structural Biology Division, University of Queensland 4072, Australia
| | - Megan L. O'Mara
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Christopher A. McDevitt
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
| | - Andrew J. Thomson
- Henry Wellcome Unit for Biological EPR, School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK
| | - Ian D. Kerr
- School of Life Sciences, University of Nottingham, Queen’s Medical Centre, Nottingham, NG7 2UH.UK
| | - Fraser MacMillan
- Henry Wellcome Unit for Biological EPR, School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK
| | - Richard Callaghan
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
- Division of Biomedical Science & Biochemistry, Research School of Biology, College of Medicine, Biology & Environment, The Australian National University, Canberra ACT 0200 Australia
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27
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Zakeri-Milani P, Valizadeh H. Intestinal transporters: enhanced absorption through P-glycoprotein-related drug interactions. Expert Opin Drug Metab Toxicol 2014; 10:859-71. [DOI: 10.1517/17425255.2014.905543] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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28
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O’Mara ML, Mark AE. Structural characterization of two metastable ATP-bound states of P-glycoprotein. PLoS One 2014; 9:e91916. [PMID: 24632881 PMCID: PMC3954865 DOI: 10.1371/journal.pone.0091916] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 02/18/2014] [Indexed: 12/30/2022] Open
Abstract
ATP Binding Cassette (ABC) transporters couple the binding and hydrolysis of ATP to the transport of substrate molecules across the membrane. The mechanism by which ATP binding and/or hydrolysis drives the conformational changes associated with substrate transport has not yet been characterized fully. Here, changes in the conformation of the ABC export protein P-glycoprotein on ATP binding are examined in a series of molecular dynamics simulations. When one molecule of ATP is placed at the ATP binding site associated with each of the two nucleotide binding domains (NBDs), the membrane-embedded P-glycoprotein crystal structure adopts two distinct metastable conformations. In one, each ATP molecule interacts primarily with the Walker A motif of the corresponding NBD. In the other, the ATP molecules interacts with both Walker A motif of one NBD and the Signature motif of the opposite NBD inducing the partial dimerization of the NBDs. This interaction is more extensive in one of the two ATP binding site, leading to an asymmetric structure. The overall conformation of the transmembrane domains is not altered in either of these metastable states, indicating that the conformational changes associated with ATP binding observed in the simulations in the absence of substrate do not lead to the outward-facing conformation and thus would be insufficient in themselves to drive transport. Nevertheless, the metastable intermediate ATP-bound conformations observed are compatible with a wide range of experimental cross-linking data demonstrating the simulations do capture physiologically important conformations. Analysis of the interaction between ATP and its cofactor Mg(2+) with each NBD indicates that the coordination of ATP and Mg(2+) differs between the two NBDs. The role structural asymmetry may play in ATP binding and hydrolysis is discussed. Furthermore, we demonstrate that our results are not heavily influenced by the crystal structure chosen for initiation of the simulations.
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Affiliation(s)
- Megan L. O’Mara
- School of Chemistry and Molecular Biosciences (SCMB), The Institute for Molecular Biosciences (IMB), The University of Queensland, Brisbane, Queensland, Australia
- School of Mathematics and Physics (SMP), The Institute for Molecular Biosciences (IMB), The University of Queensland, Brisbane, Queensland, Australia
| | - Alan E. Mark
- School of Chemistry and Molecular Biosciences (SCMB), The Institute for Molecular Biosciences (IMB), The University of Queensland, Brisbane, Queensland, Australia
- The Institute for Molecular Biosciences (IMB), The University of Queensland, Brisbane, Queensland, Australia
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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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Pollock NL, McDevitt CA, Collins R, Niesten PHM, Prince S, Kerr ID, Ford RC, Callaghan R. Improving the stability and function of purified ABCB1 and ABCA4: the influence of membrane lipids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:134-47. [PMID: 24036079 DOI: 10.1016/j.bbamem.2013.09.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 08/27/2013] [Accepted: 09/03/2013] [Indexed: 12/17/2022]
Abstract
ATP Binding Cassette (ABC) transporters play prominent roles in numerous cellular processes and many have been implicated in human diseases. Unfortunately, detailed mechanistic information on the majority of ABC transporters has not yet been elucidated. The slow rate of progress of molecular and high resolution structural studies may be attributed to the difficulty in the investigation of integral membrane proteins. These difficulties include the expression of functional, non-aggregated protein in heterologous systems. Furthermore, the extraction of membrane proteins from source material remains a major bottle-neck in the process since there are relatively few guidelines for selection of an appropriate detergent to achieve optimal extraction. Whilst affinity tag strategies have simplified the purification of membrane proteins; many challenges remain. For example, the chromatographic process and associated steps can rapidly lead to functional inactivation, random aggregation, or even precipitation of the target protein. Furthermore, optimisation of high yield and purity, does not guarantee successful structure determination. Based on this series of potential issues, any investigation into structure-function of membrane proteins requires a systematic evaluation of preparation quality. In particular, the evaluation should focus on function, homogeneity and mono-dispersity. The present investigation provides a detailed assessment of the quality of purified ATP Binding Cassette (ABC) transporters; namely ABCB1 (P-gp) and ABCA4 (ABCR). A number of suggestions are provided to facilitate the production of functional, homogeneous and mono-disperse preparations using the insect cell expression system. Finally, the ABCA4 samples have been used to provide structural insights into this essential photo-receptor cell protein.
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Affiliation(s)
- Naomi L Pollock
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
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31
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Structures of ABCB10, a human ATP-binding cassette transporter in apo- and nucleotide-bound states. Proc Natl Acad Sci U S A 2013; 110:9710-5. [PMID: 23716676 DOI: 10.1073/pnas.1217042110] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
ABCB10 is one of the three ATP-binding cassette (ABC) transporters found in the inner membrane of mitochondria. In mammals ABCB10 is essential for erythropoiesis, and for protection of mitochondria against oxidative stress. ABCB10 is therefore a potential therapeutic target for diseases in which increased mitochondrial reactive oxygen species production and oxidative stress play a major role. The crystal structure of apo-ABCB10 shows a classic exporter fold ABC transporter structure, in an open-inwards conformation, ready to bind the substrate or nucleotide from the inner mitochondrial matrix or membrane. Unexpectedly, however, ABCB10 adopts an open-inwards conformation when complexed with nonhydrolysable ATP analogs, in contrast to other transporter structures which adopt an open-outwards conformation in complex with ATP. The three complexes of ABCB10/ATP analogs reported here showed varying degrees of opening of the transport substrate binding site, indicating that in this conformation there is some flexibility between the two halves of the protein. These structures suggest that the observed plasticity, together with a portal between two helices in the transmembrane region of ABCB10, assist transport substrate entry into the substrate binding cavity. These structures indicate that ABC transporters may exist in an open-inwards conformation when nucleotide is bound. We discuss ways in which this observation can be aligned with the current views on mechanisms of ABC transporters.
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32
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Zembruski NCL, Nguyen CDL, Theile D, Ali RMM, Herzog M, Hofhaus G, Heintz U, Burhenne J, Haefeli WE, Weiss J. Liposomal Sphingomyelin Influences the Cellular Lipid Profile of Human Lymphoblastic Leukemia Cells without Effect on P-Glycoprotein Activity. Mol Pharm 2013; 10:1020-34. [DOI: 10.1021/mp300485j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Nadine C. L. Zembruski
- Department
of Clinical Pharmacology
and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer
Feld 410, 69120 Heidelberg, Germany
| | - Chi D. L. Nguyen
- Department
of Clinical Pharmacology
and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer
Feld 410, 69120 Heidelberg, Germany
| | - Dirk Theile
- Department
of Clinical Pharmacology
and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer
Feld 410, 69120 Heidelberg, Germany
| | - Ramadan M. M. Ali
- Department
of Clinical Pharmacology
and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer
Feld 410, 69120 Heidelberg, Germany
| | - Melanie Herzog
- Department
of Clinical Pharmacology
and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer
Feld 410, 69120 Heidelberg, Germany
| | - Götz Hofhaus
- CryoEM, CellNetWorks, University
of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Udo Heintz
- Department
of Clinical Pharmacology
and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer
Feld 410, 69120 Heidelberg, Germany
| | - Jürgen Burhenne
- Department
of Clinical Pharmacology
and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer
Feld 410, 69120 Heidelberg, Germany
| | - Walter E. Haefeli
- Department
of Clinical Pharmacology
and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer
Feld 410, 69120 Heidelberg, Germany
| | - Johanna Weiss
- Department
of Clinical Pharmacology
and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer
Feld 410, 69120 Heidelberg, Germany
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33
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O'Mara ML, Mark AE. The Effect of Environment on the Structure of a Membrane Protein: P-Glycoprotein under Physiological Conditions. J Chem Theory Comput 2012; 8:3964-76. [PMID: 26593033 DOI: 10.1021/ct300254y] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The stability of the crystal structure of the multidrug transporter P-glycoprotein proposed by Aller et al. (PDBid 3G5U ) has been examined under different environmental conditions using molecular dynamics. We show that in the presence of the detergent cholate, the structure of P-glycoprotein solved at pH 7.5 is stable. However, when incorporated into a cholesterol-enriched POPC membrane in the presence of 150 mM NaCl, the structure rapidly deforms. Only when the simulation conditions closely matched the experimental conditions under which P-glycoprotein is transport active was a stable conformation obtained. Specifically, the presence of Mg(2+), which bound to distinct sites in the nucleotide binding domains (NBDs), and the double protonation of the catalytic histidines (His583 and His1228) and His149 were required. While the structure obtained in a membrane environment under these conditions is very similar to the crystal structure of Aller et al., there are several key differences. The NBDs are in direct contact, reminiscent of the open state of MalK. The angle between the transmembrane domains is also increased, resulting in an outward motion of the intracellular loops. Notably, the structures obtained from the simulations provide a better match to a range of experimental cross-linking data than does the original 3G5U-a crystal structure. This work highlights the effect small changes in environmental conditions can have of the conformation of a membrane protein and the importance of representing the experimental conditions appropriately in modeling studies.
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Affiliation(s)
- Megan L O'Mara
- School of Chemistry and Molecular Biosciences (SCMB), University of Queensland, Brisbane, QLD 4072, Australia
| | - Alan E Mark
- School of Chemistry and Molecular Biosciences (SCMB), University of Queensland, Brisbane, QLD 4072, Australia.,Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
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Agnani D, Acharya P, Martinez E, Tran TT, Abraham F, Tobin F, Ellens H, Bentz J. Fitting the elementary rate constants of the P-gp transporter network in the hMDR1-MDCK confluent cell monolayer using a particle swarm algorithm. PLoS One 2011; 6:e25086. [PMID: 22028772 PMCID: PMC3196501 DOI: 10.1371/journal.pone.0025086] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 08/25/2011] [Indexed: 11/18/2022] Open
Abstract
P-glycoprotein, a human multidrug resistance transporter, has been extensively studied due to its importance to human health and disease. In order to understand transport kinetics via P-gp, confluent cell monolayers overexpressing P-gp are widely used. The purpose of this study is to obtain the mass action elementary rate constants for P-gp's transport and to functionally characterize members of P-gp's network, i.e., other transporters that transport P-gp substrates in hMDR1-MDCKII confluent cell monolayers and are essential to the net substrate flux. Transport of a range of concentrations of amprenavir, loperamide, quinidine and digoxin across the confluent monolayer of cells was measured in both directions, apical to basolateral and basolateral to apical. We developed a global optimization algorithm using the Particle Swarm method that can simultaneously fit all datasets to yield accurate and exhaustive fits of these elementary rate constants. The statistical sensitivity of the fitted values was determined by using 24 identical replicate fits, yielding simple averages and standard deviations for all of the kinetic parameters, including the efflux active P-gp surface density. Digoxin required additional basolateral and apical transporters, while loperamide required just a basolateral tranporter. The data were better fit by assuming bidirectional transporters, rather than active importers, suggesting that they are not MRP or active OATP transporters. The P-gp efflux rate constants for quinidine and digoxin were about 3-fold smaller than reported ATP hydrolysis rate constants from P-gp proteoliposomes. This suggests a roughly 3∶1 stoichiometry between ATP hydrolysis and P-gp transport for these two drugs. The fitted values of the elementary rate constants for these P-gp substrates support the hypotheses that the selective pressures on P-gp are to maintain a broad substrate range and to keep xenobiotics out of the cytosol, but not out of the apical membrane.
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Affiliation(s)
- Deep Agnani
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Poulomi Acharya
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Esteban Martinez
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Thuy Thanh Tran
- Preclinical Drug Metabolism and Pharmacokinetics, GlaxoSmithKline, King of Prussia, Pennsylvania, United States of America
| | - Feby Abraham
- Scientific Computing and Mathematical Modeling, GlaxoSmithKline, King of Prussia, Pennsylvania, United States of America
| | - Frank Tobin
- Scientific Computing and Mathematical Modeling, GlaxoSmithKline, King of Prussia, Pennsylvania, United States of America
| | - Harma Ellens
- Preclinical Drug Metabolism and Pharmacokinetics, GlaxoSmithKline, King of Prussia, Pennsylvania, United States of America
| | - Joe Bentz
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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35
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Tamashevski AV, Kozlova NM, Goncharova NV, Zubritskaya GP, Slobozhanina EI. Effect of cholesterol on the functional activity of proteins responsible for the resistance of human lymphocytes to xenobiotics. Biophysics (Nagoya-shi) 2011. [DOI: 10.1134/s0006350911030262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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36
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Riou M, Guégnard F, Sizaret PY, Le Vern Y, Kerboeuf D. Drug resistance is affected by colocalization of P-glycoproteins in raft-like structures unexpected in eggshells of the nematode Haemonchus contortus. Biochem Cell Biol 2010; 88:459-67. [DOI: 10.1139/o09-126] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In nematodes as in other eukaryotes, there is increasing evidence that drug resistance depends on both changes in the drug cellular targets and in nonspecific mechanisms, involving cellular detoxification by efflux pumps. In vertebrates, P-glycoproteins (Pgp) are membrane efflux pumps responsible for the elimination of xenobiotic agents, especially drugs. We previously reported the presence of Pgp pumps in eggshells and cuticles of the nematode Haemonchus contortus. Eggshells and cuticles are different from cell membranes, in particular they include a chitin layer. Nevertheless these structures present some common biological features with cell membranes and play a role in xenobiotic transport. Pgp activity has been shown to depend on the lipid environment and, in particular, on the cholesterol content in both vertebrate and nematode models. In vertebrates, Pgp is in part located in membrane cholesterol-enriched microdomains, the rafts. We describe here, for the first time, lipid microdomains in eggshells that could correspond with raft-like structures (RLSs). Moreover, a large proportion of the Pgp was shown to colocalize with these RLSs. The functional consequences of the colocalization for xenobiotic transport and thus drug resistance in nematodes were analyzed and compared with results obtained in vertebrates. An understanding of such mechanisms is crucial in overcoming the failure of drug treatments due to the development of resistance.
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Affiliation(s)
- Mickaël Riou
- Multiresistances and Antiparasitic drugs team, Institut national de la recherche agronomique (INRA), Unité de recherche (UR)1282, Animal Infectiology & Public Health (IASP), Nouzilly, F-37380, France
- Cell Biology Laboratory – Electronic Microscopies, Faculty of Medicine, Tours University, 10 boulevard Tonnellé, F-37032 Tours, France
- Flow Cytometry Laboratory, INRA, Nouzilly, F-37380, France
| | - Fabrice Guégnard
- Multiresistances and Antiparasitic drugs team, Institut national de la recherche agronomique (INRA), Unité de recherche (UR)1282, Animal Infectiology & Public Health (IASP), Nouzilly, F-37380, France
- Cell Biology Laboratory – Electronic Microscopies, Faculty of Medicine, Tours University, 10 boulevard Tonnellé, F-37032 Tours, France
- Flow Cytometry Laboratory, INRA, Nouzilly, F-37380, France
| | - Pierre-Yves Sizaret
- Multiresistances and Antiparasitic drugs team, Institut national de la recherche agronomique (INRA), Unité de recherche (UR)1282, Animal Infectiology & Public Health (IASP), Nouzilly, F-37380, France
- Cell Biology Laboratory – Electronic Microscopies, Faculty of Medicine, Tours University, 10 boulevard Tonnellé, F-37032 Tours, France
- Flow Cytometry Laboratory, INRA, Nouzilly, F-37380, France
| | - Yves Le Vern
- Multiresistances and Antiparasitic drugs team, Institut national de la recherche agronomique (INRA), Unité de recherche (UR)1282, Animal Infectiology & Public Health (IASP), Nouzilly, F-37380, France
- Cell Biology Laboratory – Electronic Microscopies, Faculty of Medicine, Tours University, 10 boulevard Tonnellé, F-37032 Tours, France
- Flow Cytometry Laboratory, INRA, Nouzilly, F-37380, France
| | - Dominique Kerboeuf
- Multiresistances and Antiparasitic drugs team, Institut national de la recherche agronomique (INRA), Unité de recherche (UR)1282, Animal Infectiology & Public Health (IASP), Nouzilly, F-37380, France
- Cell Biology Laboratory – Electronic Microscopies, Faculty of Medicine, Tours University, 10 boulevard Tonnellé, F-37032 Tours, France
- Flow Cytometry Laboratory, INRA, Nouzilly, F-37380, France
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Heikal A, Box K, Rothnie A, Storm J, Callaghan R, Allen M. The stabilisation of purified, reconstituted P-glycoprotein by freeze drying with disaccharides. Cryobiology 2009; 58:37-44. [PMID: 18983838 PMCID: PMC2791872 DOI: 10.1016/j.cryobiol.2008.10.125] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 09/23/2008] [Accepted: 10/02/2008] [Indexed: 11/15/2022]
Abstract
The drug efflux pump P-glycoprotein (P-gp) (ABCB1) confers multidrug resistance, a major cause of failure in the chemotherapy of tumours, exacerbated by a shortage of potent and selective inhibitors. A high throughput assay using purified P-gp to screen and characterise potential inhibitors would greatly accelerate their development. However, long-term stability of purified reconstituted ABCB1 can only be reliably achieved with storage at -80 degrees C. For example, at 20 degrees C, the activity of ABCB1 was abrogated with a half-life of <1 day. The aim of this investigation was to stabilise purified, reconstituted ABCB1 to enable storage at higher temperatures and thereby enable design of a high throughput assay system. The ABCB1 purification procedure was optimised to allow successful freeze drying by substitution of glycerol with the disaccharides trehalose or maltose. Addition of disaccharides resulted in ATPase activity being retained immediately following lyophilisation with no significant difference between the two disaccharides. However, during storage trehalose preserved ATPase activity for several months regardless of the temperature (e.g. 60% retention at 150 days), whereas ATPase activity in maltose purified P-gp was affected by both storage time and temperature. The data provide an effective mechanism for the production of resilient purified, reconstituted ABCB1.
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Affiliation(s)
- Adam Heikal
- University of Brighton, School of Pharmacy and Biomolecular Sciences, Cockcroft Building, Lewes Road, Brighton BN2 4GJ, UK
| | - Karl Box
- Sirius Analytical Instruments Ltd. Riverside, Unit 12 Forest Row Business Park Forest Row, East Sussex RH18 5DW, UK
| | - Alice Rothnie
- Nuffield Department of Clinical Laboratory Sciences Level 4, John Radcliffe Hospital, Oxford University, Oxford OX3 9DU, UK
| | - Janet Storm
- Nuffield Department of Clinical Laboratory Sciences Level 4, John Radcliffe Hospital, Oxford University, Oxford OX3 9DU, UK
| | - Richard Callaghan
- Nuffield Department of Clinical Laboratory Sciences Level 4, John Radcliffe Hospital, Oxford University, Oxford OX3 9DU, UK
| | - Marcus Allen
- University of Brighton, School of Pharmacy and Biomolecular Sciences, Cockcroft Building, Lewes Road, Brighton BN2 4GJ, UK.
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Bucher K, Belli S, Wunderli-Allenspach H, Krämer SD. P-glycoprotein in proteoliposomes with low residual detergent: the effects of cholesterol. Pharm Res 2007; 24:1993-2004. [PMID: 17497080 DOI: 10.1007/s11095-007-9326-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Accepted: 04/25/2007] [Indexed: 11/29/2022]
Abstract
PURPOSE There is evidence that cholesterol affects the ATPase and transport functions of P-glycoprotein (P-gp). To study the influence of cholesterol on P-gp in a well defined lipid environment, we reconstituted P-gp in egg phosphatidylcholine (PhC) and PhC/cholesterol proteoliposomes with negligible residual amounts of detergents. MATERIALS AND METHODS P-gp proteoliposomes were prepared by continuous dialysis from micelles consisting of P-gp, lipids, sodium dodecyl sulfate and cholate. Basal and modulator-induced ATPase activities were studied in an established enzyme assay. Modulator affinities to P-gp and to the lipid bilayers were determined by equilibrium dialysis. RESULTS In the absence of cholesterol the basal ATPase activity was six fold lower than in the presence of 20 or 40% cholesterol, and no P-gp binding and ATPase induction was detected for the tested modulators verapamil and progesterone. In proteoliposomes containing 20 and 40% cholesterol, respectively, the modulators showed significant P-gp binding and ATPase activation. The concentration of the modulators for half maximal activation of the ATPase was higher with 40% than with 20% cholesterol. CONCLUSIONS Cholesterol influences P-gp in three ways: (a) it enhances its basal ATPase activity, (b) it renders P-gp sensitive towards the modulators verapamil and progesterone and (c) it affects the modulator concentration at half maximal ATPase activation.
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Affiliation(s)
- Karsten Bucher
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093, Zurich, Switzerland
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39
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Cerf E, Gasper R, Belani JD, Rychnovsky S, Chang XB, Buyse F, Ruysschaert JM. Multidrug resistance protein 1 is not associated to detergent-resistant membranes. Biochem Biophys Res Commun 2007; 355:1025-30. [PMID: 17336270 DOI: 10.1016/j.bbrc.2007.02.075] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 02/14/2007] [Indexed: 11/26/2022]
Abstract
Multidrug resistance protein 1 (MRP1) is a member of the ATP-binding cassette superfamily. Using the energy provided by ATP hydrolysis, it transports a broad spectrum of substrates across the plasma membrane, including hormones, leukotriene C(4), bile salts, and anti-cancer drugs. Recent works have suggested that P-glycoprotein is associated to cholesterol and sphingolipid-rich membrane microdomains and that cholesterol upregulates its ATPase and drug transport activities. Confocal microscopy experiments and Triton X-100 extraction of detergent-resistant membranes provide evidence that MRP1 is not located in raft-like structures and that its activity is downregulated by cholesterol. The data are discussed in terms of cholesterol-protein interaction and topology.
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Affiliation(s)
- Emilie Cerf
- Structure et Fonction des Membranes Biologiques, Centre de Biologie Structurale et de Bioinformatique, Université Libre de Bruxelles, Boulevard du Triomphe, B-1050 Brussels, Belgium
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40
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Sharom FJ. Shedding light on drug transport: structure and function of the P-glycoprotein multidrug transporter (ABCB1). Biochem Cell Biol 2007; 84:979-92. [PMID: 17215884 DOI: 10.1139/o06-199] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
P-glycoprotein (Pgp; ABCB1), a member of the ATP-binding cassette (ABC) superfamily, exports structurally diverse hydrophobic compounds from the cell, driven by ATP hydrolysis. Pgp expression has been linked to the efflux of chemotherapeutic drugs in human cancers, leading to multidrug resistance (MDR). The protein also plays an important physiological role in limiting drug uptake in the gut and entry into the brain. Substrates partition into the lipid bilayer before interacting with Pgp, which has been proposed to function as a hydrophobic vacuum cleaner. Low- and medium-resolution structural models of Pgp suggest that the 2 nucleotide-binding domains are closely associated to form a nucleotide sandwich dimer. Pgp is an outwardly directed flippase for fluorescent phospholipid and glycosphingolipid derivatives, which suggests that it may also translocate drug molecules from the inner to the outer membrane leaflet. The ATPase catalytic cycle of the protein is thought to proceed via an alternating site mechanism, although the details are not understood. The lipid bilayer plays an important role in Pgp function, and may regulate both the binding and transport of drugs. This review focuses on the structure and function of Pgp, and highlights the importance of fluorescence spectroscopic techniques in exploring the molecular details of this enigmatic transporter.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1/chemistry
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP Binding Cassette Transporter, Subfamily B, Member 1/physiology
- ATP-Binding Cassette Transporters/metabolism
- Adenosine Triphosphate/metabolism
- Animals
- Awards and Prizes
- Biological Transport/drug effects
- Drug Resistance, Multiple
- Humans
- Models, Biological
- Models, Molecular
- Organic Anion Transporters/metabolism
- Spectrometry, Fluorescence
- Structure-Activity Relationship
- Substrate Specificity
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Affiliation(s)
- Frances J Sharom
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
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Meyer dos Santos S, Meyer Dos Santos S, Weber CC, Franke C, Müller WE, Eckert GP. Cholesterol: Coupling between membrane microenvironment and ABC transporter activity. Biochem Biophys Res Commun 2007; 354:216-21. [PMID: 17223079 DOI: 10.1016/j.bbrc.2006.12.202] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Accepted: 12/23/2006] [Indexed: 01/16/2023]
Abstract
Lipid composition of biological membranes is closely related to the function of the ATP-binding cassette (ABC) transporter P-Glycoprotein (Pgp). Herein, we studied how membrane physico-chemical properties affect Pgp-activity. We effectively modulated the cellular cholesterol content using methyl-beta-cyclodextrin (MbetaCD) and MbetaCD-cholesterol-inclusion complex. Pgp was not liberated from the plasma membrane during cholesterol modulation and functional inhibition of Pgp was related to varying cholesterol levels in the plasma membrane. Our data indicate that membrane fluidity does not solely account for cholesterol dependent modifications of Pgp-activity. Therefore, we isolated lipid rafts and examined distinct membrane microdomains. Both depletion and cholesterol enrichment induces a disassembly of lipid rafts. In cholesterol-depleted cell membranes a shift in the Pgp localisation to detergent soluble fractions was observed. Enrichment of membrane cholesterol changed lipid raft distribution but not the localisation of Pgp. From our data we conclude that Pgp-transport capacity depends on accurate lipid raft properties.
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Affiliation(s)
- Sascha Meyer dos Santos
- Department of Pharmacology, ZAFES, Biocenter Niederursel, N260, Max-von-Laue Str. 9, University of Frankfurt, Germany
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42
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Kimura Y, Kioka N, Kato H, Matsuo M, Ueda K. Modulation of drug-stimulated ATPase activity of human MDR1/P-glycoprotein by cholesterol. Biochem J 2007; 401:597-605. [PMID: 17029589 PMCID: PMC1820799 DOI: 10.1042/bj20060632] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
MDR1 (multidrug resistance 1)/P-glycoprotein is an ATP-driven transporter which excretes a wide variety of structurally unrelated hydrophobic compounds from cells. It is suggested that drugs bind to MDR1 directly from the lipid bilayer and that cholesterol in the bilayer also interacts with MDR1. However, the effects of cholesterol on drug-MDR1 interactions are still unclear. To examine these effects, human MDR1 was expressed in insect cells and purified. The purified MDR1 protein was reconstituted in proteoliposomes containing various concentrations of cholesterol and enzymatic parameters of drug-stimulated ATPase were compared. Cholesterol directly binds to purified MDR1 in a detergent soluble form and the effects of cholesterol on drug-stimulated ATPase activity differ from one drug to another. The effects of cholesterol on K(m) values of drug-stimulated ATPase activity were strongly correlated with the molecular mass of that drug. Cholesterol increases the binding affinity of small drugs (molecular mass <500 Da), but does not affect that of drugs with a molecular mass of between 800 and 900 Da, and suppresses that of valinomycin (molecular mass >1000 Da). V(max) values for rhodamine B and paclitaxel are also increased by cholesterol, suggesting that cholesterol affects turnover as well as drug binding. Paclitaxel-stimulated ATPase activity of MDR1 is enhanced in the presence of stigmasterol, sitosterol and campesterol, as well as cholesterol, but not ergosterol. These results suggest that the drug-binding site of MDR1 may best fit drugs with a molecular mass of between 800 and 900 Da, and that cholesterol may support the recognition of smaller drugs by adjusting the drug-binding site and play an important role in the function of MDR1.
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Affiliation(s)
- Yasuhisa Kimura
- Laboratory of Cellular Biochemistry, Division of Applied Life Sciences, Kyoto University Graduate School of Agriculture, Kyoto 606-8502, Japan
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43
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McDevitt CA, Collins RF, Conway M, Modok S, Storm J, Kerr ID, Ford RC, Callaghan R. Purification and 3D structural analysis of oligomeric human multidrug transporter ABCG2. Structure 2007; 14:1623-32. [PMID: 17098188 DOI: 10.1016/j.str.2006.08.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 08/04/2006] [Accepted: 08/08/2006] [Indexed: 12/16/2022]
Abstract
ABCG2 is a multidrug efflux pump associated with resistance of cancer cells to a plethora of unrelated drugs. ABCG2 is a "half-transporter," and previous studies have indicated that it forms homodimers and higher oligomeric species. In this manuscript, electron microscopic structural analysis directly addressed this issue. An N-terminal hexahistidine-tagged ABCG2(R482G) isoform was expressed to high levels in insect cells. An extensive detergent screen was employed to effect extraction of ABCG2(R482G) from membranes and identified only the fos-choline detergents as efficient. Soluble protein was purified to >95% homogeneity by a three-step procedure while retaining the ability to bind substrates. Cryonegative stain electron microscopy of purified ABCG2(R482G) provided 3D structural data at a resolution of approximately 18 A. Single-particle analysis revealed that the complex forms a tetrameric complex ( approximately 180 A in diameter x approximately 140 A high) with an aqueous central region. We interpret the tetrameric structure as comprising four homodimeric ABCG2(R482G) complexes.
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Affiliation(s)
- Christopher A McDevitt
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, United Kingdom
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44
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Tikhonova EB, Devroy VK, Lau SY, Zgurskaya HI. Reconstitution of the Escherichia coli macrolide transporter: the periplasmic membrane fusion protein MacA stimulates the ATPase activity of MacB. Mol Microbiol 2007; 63:895-910. [PMID: 17214741 DOI: 10.1111/j.1365-2958.2006.05549.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Periplasmic membrane fusion proteins (MFPs) are essential components of the type I protein secretion systems and drug efflux pumps in Gram-negative bacteria. Previous studies suggested that MFPs connect the inner and outer membrane components of the transport systems and by this means co-ordinate the transfer of substrates across the two membranes. In this study, we purified and reconstituted the macrolide transporter MacAB from Escherichia coli. Here, MacA is a periplasmic MFP and MacB is an ABC-type transporter. Similar to other MFP-dependent transporters from E. coli, the in vivo function of MacAB requires the outer membrane channel TolC. The purified MacB displayed a basal ATPase activity in detergent micelles. This activity conformed to Michaelis-Menten kinetics but was unresponsive to substrates or accessory proteins. Upon reconstitution into proteoliposomes, the ATPase activity of MacB was strictly dependent on MacA. The catalytic efficiency of MacAB ATPase was more than 45-fold higher than the activity of MacB alone. Both the N- and C-terminal regions of MacA were essential for this activity. MacA stimulated MacB ATPase only in phospholipid bilayers and did not need the presence of macrolides. Our results suggest that MacA is a functional subunit of the MacB transporter.
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Affiliation(s)
- Elena B Tikhonova
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA
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45
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Acharya P, Tran TT, Polli JW, Ayrton A, Ellens H, Bentz J. P-Glycoprotein (P-gp) expressed in a confluent monolayer of hMDR1-MDCKII cells has more than one efflux pathway with cooperative binding sites. Biochemistry 2006; 45:15505-19. [PMID: 17176072 DOI: 10.1021/bi060593b] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The multidrug resistance transporter P-glycoprotein (P-gp) effluxes a wide range of substrates and can be affected by a wide range of inhibitors or modulators. Many studies have presented classifications for these binding interactions, within either the context of equilibrium binding or the Michaelis-Menten enzyme analysis of the ATPase activity of P-gp. Our approach is to study P-gp transport and its inhibition using a physiologically relevant confluent monolayer of hMDR1-MDCKII cells. We measure the elementary rate constants for P-gp efflux of substrates and study inhibition using pairwise combinations with a different unlabeled substrate acting as the inhibitor. Our current kinetic model for P-gp has only a single binding site, because a previous study proved that the mass-action kinetics of efflux of a single substrate were not sensitive to whether there are one or more substrate-binding and efflux sites. In this study, using this one-site model, we found that, with "high" concentrations of either a substrate or an inhibitor, the elementary rate constants fitted independently for each of the substrates alone quantitatively predicted the efflux curves, simply applying the assumption that binding at the "one site" was competitive. On the other hand, at "low" concentrations of both the substrate and inhibitor, we found no inhibition of the substrate efflux, despite the fact that both the substrate and inhibitor were being well-effluxed. This was not an effect of excess "empty" P-gp molecules, because the competitive efflux model takes site occupancy into account. Rather, it is quantitative evidence that the substrate and inhibitor are being effluxed by multiple pathways within P-gp. Remarkably, increasing the substrate concentration above the "low" concentration, caused the inhibition to become competitive; i.e., the inhibitor became effective. These data and their analysis show that the binding of these substrates must be cooperative, either positive or negative.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP Binding Cassette Transporter, Subfamily B, Member 1/physiology
- Animals
- Binding, Competitive/genetics
- Biological Transport, Active/drug effects
- Biological Transport, Active/genetics
- Carbamates/antagonists & inhibitors
- Carbamates/metabolism
- Cell Line
- Cell Membrane Permeability/genetics
- Dogs
- Furans
- Humans
- Loperamide/antagonists & inhibitors
- Loperamide/metabolism
- Protein Binding/genetics
- Quinidine/pharmacology
- Signal Transduction/genetics
- Substrate Specificity/drug effects
- Substrate Specificity/genetics
- Sulfonamides/antagonists & inhibitors
- Sulfonamides/metabolism
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Affiliation(s)
- Poulomi Acharya
- Department of Bioscience and Biotechnology, Drexel University, Philadelphia, Pennsylvania 19104, USA
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46
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Sarkadi B, Homolya L, Szakács G, Váradi A. Human multidrug resistance ABCB and ABCG transporters: participation in a chemoimmunity defense system. Physiol Rev 2006; 86:1179-236. [PMID: 17015488 DOI: 10.1152/physrev.00037.2005] [Citation(s) in RCA: 536] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In this review we give an overview of the physiological functions of a group of ATP binding cassette (ABC) transporter proteins, which were discovered, and still referred to, as multidrug resistance (MDR) transporters. Although they indeed play an important role in cancer drug resistance, their major physiological function is to provide general protection against hydrophobic xenobiotics. With a highly conserved structure, membrane topology, and mechanism of action, these essential transporters are preserved throughout all living systems, from bacteria to human. We describe the general structural and mechanistic features of the human MDR-ABC transporters and introduce some of the basic methods that can be applied for the analysis of their expression, function, regulation, and modulation. We treat in detail the biochemistry, cell biology, and physiology of the ABCB1 (MDR1/P-glycoprotein) and the ABCG2 (MXR/BCRP) proteins and describe emerging information related to additional ABCB- and ABCG-type transporters with a potential role in drug and xenobiotic resistance. Throughout this review we demonstrate and emphasize the general network characteristics of the MDR-ABC transporters, functioning at the cellular and physiological tissue barriers. In addition, we suggest that multidrug transporters are essential parts of an innate defense system, the "chemoimmunity" network, which has a number of features reminiscent of classical immunology.
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Affiliation(s)
- Balázs Sarkadi
- National Medical Center, Institute of Hematology and Immunology, Membrane Research Group, Budapest, Hungary.
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Kobayashi T, Takahashi M, Nagatsuka Y, Hirabayashi Y. Lipid rafts: new tools and a new component. Biol Pharm Bull 2006; 29:1526-31. [PMID: 16880598 DOI: 10.1248/bpb.29.1526] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lipid rafts are liquid ordered membrane domains enriched with sphingolipids and cholesterol. After 20 years since the proposal of the original concept, the structure and function of lipid rafts are still obscure. Recently new tools to study lipid rafts have been developed. Lysenin is a sphingomyelin binding protein that specifically recognizes the lipid clusters. Poly(ethyleneglycol)-derivatized cholesterol ether (PEG-Chol) is a non-toxic cholesterol probe. These probes have revealed the heterogeneity of lipid rafts. The heterogeneity of lipid rafts is further supported by the discovery of a new lipid component, phosphatidylglucoside. Metabolic inhibitors are another useful tool. Sulfamisterin is a new addition to the serine palmitoyltransferase inhibitors. Recent findings have uncovered a previously unrecognized activity of a glycosphingolipid synthesis inhibitor, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP).
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Affiliation(s)
- Toshihide Kobayashi
- Lipid Biology Laboratory, RIKEN (Institute of Physical and Chemical Research), Japan.
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48
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Norris-Cervetto E, Butters TD, Martin C, Modok S, Dwek RA, Callaghan R. Can P-glycoprotein influence the bioavailability of iminosugar-based glucosylceramide synthase inhibitors? Eur J Pharmacol 2006; 530:195-204. [PMID: 16403499 DOI: 10.1016/j.ejphar.2005.11.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 11/08/2005] [Accepted: 11/14/2005] [Indexed: 10/25/2022]
Abstract
Recently developed glucosylceramide synthase inhibitors with enhanced hydrophobicity display increased bioavailability in the central nervous system (CNS). Have these improvements come at a potential risk given that the improved glucosylceramide synthase inhibitors bear the hallmarks of P-glycoprotein substrates? This question warrants attention given the potential to induce adverse drug interactions or toxicity, if glucosylceramide synthase inhibitors are administered with other P-glycoprotein substrates. The aim of this study was to determine if glucosylceramide synthase inhibitors are substrates for the multidrug transporter P-glycoprotein. Direct measurements of glucosylceramide synthase inhibitors binding to P-glycoprotein were examined, as was their ability to modulate transport by the protein. The more hydrophobic glucosylceramide synthase inhibitors caused a reduction in drug binding to P-glycoprotein. However, the compounds did not achieve this by direct interaction with the protein, but through a general membrane perturbation. Furthermore, the alterations in drug-P-glycoprotein interaction did not manifest as altered cellular accumulation of glucosylceramide synthase inhibitors or altered efficacy to reduce cellular glycolipid levels. Consequently, P-glycoprotein expression will not contribute significantly to the pharmacokinetic profile of the iminosugar glucosylceramide synthase inhibitors.
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Affiliation(s)
- Edward Norris-Cervetto
- Nuffield Department of Clinical Laboratory Sciences, Level 4, John Radcliffe Hospital, Oxford, OX3 9DU, UK
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49
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Barakat S, Gayet L, Dayan G, Labialle S, Lazar A, Oleinikov V, Coleman A, Baggetto L. Multidrug-resistant cancer cells contain two populations of P-glycoprotein with differently stimulated P-gp ATPase activities: evidence from atomic force microscopy and biochemical analysis. Biochem J 2005; 388:563-71. [PMID: 15693753 PMCID: PMC1138964 DOI: 10.1042/bj20041999] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Considerable interest exists about the localization of P-gp (P-glycoprotein) in DRMs (detergent-resistant membranes) of multidrug resistant cancer cells, in particular concerning the potential modulating role of the closely related lipids and proteins on P-gp activity. Our observation of the opposite effect of verapamil on P-gp ATPase activity from DRM and solubilized-membrane fractions of CEM-resistant leukaemia cells, and results from Langmuir experiments on membrane monolayers from resistant CEM cells, strongly suggest that two functional populations of P-gp exist. The first is located in DRM regions: it displays its optimal P-gp ATPase activity, which is almost completely inhibited by orthovanadate and activated by verapamil. The second is located elsewhere in the membrane; it displays a lower P-gp ATPase activity that is less sensitive to orthovanadate and is inhibited by verapamil. A 40% cholesterol depletion of DRM caused the loss of 52% of the P-gp ATPase activity. Cholesterol repletion allowed recovery of the initial P-gp ATPase activity. In contrast, in the solubilized-membrane-containing fractions, cholesterol depletion and repletion had no effect on the P-gp ATPase activity whereas up to 100% saturation with cholesterol induced a 58% increased P-gp ATPase activity, while no significant modification was observed for the DRM-enriched fraction. DRMs were analysed by atomic force microscopy: 40-60% cholesterol depletion was necessary to remove P-gp from DRMs. In conclusion, P-gp in DRMs appears to contain closely surrounding cholesterol that can stimulate P-gp ATPase activity to its optimal value, whereas cholesterol in the second population seems deprived of this function.
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Affiliation(s)
- Stéphane Barakat
- *Thérapie transcriptionnelle des cellules cancéreuses, IBCP - UMR 5086 CNRS UCBL, 7 Passage du Vercors, 69367 Lyon cedex 07, France
| | - Landry Gayet
- *Thérapie transcriptionnelle des cellules cancéreuses, IBCP - UMR 5086 CNRS UCBL, 7 Passage du Vercors, 69367 Lyon cedex 07, France
| | - Guila Dayan
- *Thérapie transcriptionnelle des cellules cancéreuses, IBCP - UMR 5086 CNRS UCBL, 7 Passage du Vercors, 69367 Lyon cedex 07, France
| | - Stéphane Labialle
- †McGill University, Royal Victoria Hospital, F3.32, 687 Pine avenue West, Montreal, QC, Canada H3A 1A1
| | - Adina Lazar
- ‡Assemblages moléculaires d'intérêt biologique, IBCP - UMR 5086 CNRS UCBL, 7 Passage du Vercors, 69367 Lyon cedex 07, France
| | - Vladimir Oleinikov
- §Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow B-437, GSP 117997, Russia
| | - Anthony W. Coleman
- ‡Assemblages moléculaires d'intérêt biologique, IBCP - UMR 5086 CNRS UCBL, 7 Passage du Vercors, 69367 Lyon cedex 07, France
| | - Loris G. Baggetto
- *Thérapie transcriptionnelle des cellules cancéreuses, IBCP - UMR 5086 CNRS UCBL, 7 Passage du Vercors, 69367 Lyon cedex 07, France
- To whom correspondence should be addressed (email )
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50
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Bentz J, Tran TT, Polli JW, Ayrton A, Ellens H. The Steady-State Michaelis–Menten Analysis of P-Glycoprotein Mediated Transport Through a Confluent Cell Monolayer Cannot Predict the Correct Michaelis Constant Km. Pharm Res 2005; 22:1667-77. [PMID: 16180124 DOI: 10.1007/s11095-005-6627-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Accepted: 06/14/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE Typically, the kinetics of membrane transport is analyzed using the steady-state Michaelis-Menten (or Eadie-Hofstee or Hanes) equations. This approach has been successful when the substrate is picked up from the aqueous phase, like a water-soluble enzyme, for which the Michaelis-Menten steady-state analysis was developed. For membrane transporters whose substrate resides in the lipid bilayer of the plasma membrane, like P-glycoprotein (P-gp), there has been no validation of the accuracy of the steady-state analysis because the elementary rate constants for transport were not known. METHODS Recently, we fitted the mass action elementary kinetic rate constants of P-gp transport of three different drugs through a confluent monolayer of MDCKII-hMDR1 cells. With these elementary rate constants in hand, we use computer simulations to assess the accuracy of the steady-state Michaelis-Menten parameters. This limits the simulation to parameter ranges known to be physiologically relevant. RESULTS Using over 2,300 different vectors of initial elementary parameters spanning the space bounded by the three drugs, which defines 2,300 "virtual substrates", the concentrations of substrate transported were calculated and fitted to Eadie-Hofstee plots. Acceptable plots were obtained for 1,338 cases. CONCLUSION The fitted steady-state Vmax values from the analysis correlated to within a factor of 2-3 with the values predicted from the elementary parameters. However, the fitted Km value could be generated by a wide range of underlying "molecular" Km values. This is because of the convolution of the drug passive permeability kinetics into the fitted Km. This implies that Km values measured in simpler systems, e.g., microsomes or proteoliposomes, even if accurate, would not predict the Km values for the confluent monolayer system or, by logical extension, in vivo. Reliable in vitro-in vivo extrapolation seems to require using the elementary rate constants rather than the Michaelis-Menten steady-state parameters.
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Affiliation(s)
- Joe Bentz
- Department of Bioscience and Biotechnology, Drexel University, Philadelphia, Pennsylvania, 19104, USA.
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