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Luckenbach T, Burkhardt-Medicke K. Differing temperature dependencies of functional homologs zebrafish Abcb4 and human ABCB1. Front Pharmacol 2024; 15:1426040. [PMID: 39166110 PMCID: PMC11333832 DOI: 10.3389/fphar.2024.1426040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 07/16/2024] [Indexed: 08/22/2024] Open
Abstract
The ATP binding cassette (ABC) transporters human ABCB1 and zebrafish (Danio rerio) Abcb4 are functionally homologous multixenobiotic/multidrug (MXR/MDR) efflux transporters that confer the efflux of a broad range of diverse chemical compounds from the cell. As ATPases, the transporters utilize the energy released by ATP cleavage for protein conformation changes and concomitant active transport of substrate compounds. The temperatures, at which human ABCB1 and zebrafish Abcb4 need to function, can substantially differ: Whereas the ambient temperature of human ABCB1, which is that of the human body, is constant, zebrafish Abcb4 has to be active in a wider temperature range as the body temperature of zebrafish can considerably vary, depending on the ambient water temperature (18°C-40°C). Here, we examined the effect of temperature on the ATPase activities of recombinant human ABCB1 and zebrafish Abcb4 generated with the baculovirus expression system. Incubation temperatures for enzyme reactions were set to 37°C and 27°C, corresponding to the human body temperature and the cultivation temperature of zebrafish in our lab, respectively. For stimulation and inhibition of zebrafish Abcb4 and human ABCB1 ATPase activities verapamil and cyclosporin A were added at different concentrations and 50% effect concentrations (EC50) were determined. The different temperatures had a stronger effect on the human ABCB1 than on the zebrafish Abcb4 ATPase: Differences between EC50 values for verapamil at 37°C and 27°C, respectively, were 1.8-fold for human ABCB1 but only 1.2-fold for zebrafish Abcb4. Activation energies (Ea) of basal and verapamil-stimulated ATPases, calculated based on the Arrhenius equation, were 2-fold (basal) and 1.5-fold (verapamil-stimulated) higher for human ABCB1 than for zebrafish Abcb4. The differences between zebrafish Abcb4 and human ABCB1 ATPases in temperature sensitivity and activation energy could be important for the comparison of the functional properties of the two transporter proteins in the context of pharmaco-/toxicokinetics. Related to this, our finding that at equal reaction conditions the zebrafish Abcb4 ATPase activity tended to be generally higher than that of human ABCB1 may also be important, as this may point to a higher substrate compound transport rate of Abcb4.
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Affiliation(s)
- Till Luckenbach
- Department Ecotoxicology, Helmholtz Centre for Environmental Research—UFZ, Leipzig, Germany
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Singh K, Patil RB, Patel V, Remenyik J, Hegedűs T, Goda K. Synergistic Inhibitory Effect of Quercetin and Cyanidin-3O-Sophoroside on ABCB1. Int J Mol Sci 2023; 24:11341. [PMID: 37511101 PMCID: PMC10379049 DOI: 10.3390/ijms241411341] [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: 02/06/2023] [Revised: 06/30/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023] Open
Abstract
The human ABCB1 (P-glycoprotein, Pgp) protein is an active exporter expressed in the plasma membrane of cells forming biological barriers. In accordance with its broad substrate spectrum and tissue expression pattern, it affects the pharmacokinetics of numerous chemotherapeutic drugs and it is involved in unwanted drug-drug interactions leading to side effects or toxicities. When expressed in tumor tissues, it contributes to the development of chemotherapy resistance in malignancies. Therefore, the understanding of the molecular details of the ligand-ABCB1 interactions is of crucial importance. In a previous study, we found that quercetin (QUR) hampers both the transport and ATPase activity of ABCB1, while cyandin-3O-sophroside (C3S) stimulates the ATPase activity and causes only a weak inhibition of substrate transport. In the current study, when QUR and C3S were applied together, both a stronger ATPase inhibition and a robust decrease in substrate transport were observed, supporting their synergistic ABCB1 inhibitory effect. Similar to cyclosporine A, a potent ABCB1 inhibitor, co-treatment with QUR and C3S shifted the conformational equilibrium to the "inward-facing" conformer of ABCB1, as it was detected by the conformation-selective UIC2 mAb. To gain deeper insight into the molecular details of ligand-ABCB1 interactions, molecular docking experiments and MD simulations were also carried out. Our in silico studies support that QUR and C3S can bind simultaneously to ABCB1. The most favourable ligand-ABCB1 interaction is obtained when C3S binds to the central substrate binding site and QUR occupies the "access tunnel". Our results also highlight that the strong ABCB1 inhibitory effect of the combined treatment with QUR and C3S may be exploited in chemotherapy protocols for the treatment of multidrug-resistant tumors or for improving drug delivery through pharmacological barriers.
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Affiliation(s)
- Kuljeet Singh
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - Rajesh B Patil
- Department of Pharmaceutical Chemistry, Sinhgad Technical Education Society's Sinhgad College of Pharmacy, OffSinhgad Road, Vadgaon (Bk), Pune 411041, Maharashtra, India
| | - Vikas Patel
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Judit Remenyik
- Institute of Food Technology, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, 4032 Debrecen, Hungary
| | - Tamás Hegedűs
- Department of Biophysics and Radiation Biology, Semmelweis University, 1085 Budapest, Hungary
- ELKH-SE Biophysical Virology Research Group, Eötvös Loránd Research Network, 1052 Budapest, Hungary
| | - Katalin Goda
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
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Interaction of a Homologous Series of Amphiphiles with P-glycoprotein in a Membrane Environment-Contributions of Polar and Non-Polar Interactions. Pharmaceutics 2023; 15:pharmaceutics15010174. [PMID: 36678803 PMCID: PMC9862096 DOI: 10.3390/pharmaceutics15010174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/06/2022] [Accepted: 12/26/2022] [Indexed: 01/05/2023] Open
Abstract
The transport of drugs by efflux transporters in biomembranes limits their bioavailability and is a major determinant of drug resistance development by cancer cells and pathogens. A large number of chemically dissimilar drugs are transported, and despite extensive studies, the molecular determinants of substrate specificity are still not well understood. In this work, we explore the role of polar and non-polar interactions on the interaction of a homologous series of fluorescent amphiphiles with the efflux transporter P-glycoprotein. The interaction of the amphiphiles with P-glycoprotein is evaluated through effects on ATPase activity, efficiency in inhibition of [125I]-IAAP binding, and partition to the whole native membranes containing the transporter. The results were complemented with partition to model membranes with a representative lipid composition, and details on the interactions established were obtained from MD simulations. We show that when the total concentration of amphiphile is considered, the binding parameters obtained are apparent and do not reflect the affinity for P-gp. A new formalism is proposed that includes sequestration of the amphiphiles in the lipid bilayer and the possible binding of several molecules in P-gp's substrate-binding pocket. The intrinsic binding affinity thus obtained is essentially independent of amphiphile hydrophobicity, highlighting the importance of polar interactions. An increase in the lipophilicity and amphiphilicity led to a more efficient association with the lipid bilayer, which maintains the non-polar groups of the amphiphiles in the bilayer, while the polar groups interact with P-gp's binding pocket. The presence of several amphiphiles in this orientation is proposed as a mechanism for inhibition of P-pg function.
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Krapf MK, Gallus J, Spindler A, Wiese M. Synthesis and biological evaluation of quinazoline derivatives - A SAR study of novel inhibitors of ABCG2. Eur J Med Chem 2018; 161:506-525. [PMID: 30390439 DOI: 10.1016/j.ejmech.2018.10.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/08/2018] [Accepted: 10/10/2018] [Indexed: 11/16/2022]
Abstract
Multidrug resistance (MDR) is a major obstacle for effective chemotherapeutic treatment of cancer frequently leading to failure of the therapy. MDR is often associated with the overexpression of ABC transport proteins like ABCB1 or ABCG2 which efflux harmful substances out of cells at the cost of ATP hydrolysis. One way to overcome MDR is to apply potent inhibitors of ABC transporters to restore the sensitivity of the cells toward cytostatic agents. This study focusses on the synthesis and evaluation of novel 2,4-disubstituted quinazoline derivatives regarding the structure-activity-relationship (SAR), their ability to reverse MDR and their mode of interaction with ABCG2. Hence, the inhibitory potency and selectivity toward ABCG2 was determined. Moreover, the intrinsic cytotoxicity and the reversal of MDR were investigated. Interaction type studies with the substrate Hoechst 33342 and conformational analyses of ABCG2 with 5D3 monoclonal antibody were performed for a better understanding of the underlying mechanisms. In our study we could further enhance the inhibitory effect against ABCG2 (compound 31, IC50: 55 nM) and identify the structural features that are crucial for inhibitory potency, the impact on transport activity and binding to the protein.
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Affiliation(s)
- Michael K Krapf
- Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Jennifer Gallus
- Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Anna Spindler
- Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Michael Wiese
- Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany.
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Krapf MK, Gallus J, Namasivayam V, Wiese M. 2,4,6-Substituted Quinazolines with Extraordinary Inhibitory Potency toward ABCG2. J Med Chem 2018; 61:7952-7976. [PMID: 30075623 DOI: 10.1021/acs.jmedchem.8b01011] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Several members of the ABC transporter superfamily play a decisive role in the development of multidrug resistance (MDR) in cancer. One of these MDR associated efflux transporters is ABCG2. One way to overcome this MDR is the coadministration of potent inhibitors of ABCG2. In this study, we identified novel inhibitors containing a 2,4,6-substituted quinazoline scaffold. Introduction of a 6-nitro function led to extraordinarily potent compounds that were highly selective for ABCG2 and also able to reverse the MDR toward the chemotherapeutic drugs SN-38 and mitoxantrone. The binding of substrate Hoechst 33342 and the two potent inhibitors 31 and 41 which differ in their mechanism of inhibition was rationalized using the recently published cryo-EM structures of ABCG2. For a better understanding of the interaction between the inhibitors and ABCG2, additional investigations regarding the ATPase activity, the interaction with Hoechst 33342, and with the conformational sensitive 5D3 antibody were carried out.
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Affiliation(s)
- Michael K Krapf
- Pharmaceutical Institute University of Bonn An der Immenburg 4 53121 Bonn , Germany
| | - Jennifer Gallus
- Pharmaceutical Institute University of Bonn An der Immenburg 4 53121 Bonn , Germany
| | | | - Michael Wiese
- Pharmaceutical Institute University of Bonn An der Immenburg 4 53121 Bonn , Germany
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Synthesis and biological investigation of 2,4-substituted quinazolines as highly potent inhibitors of breast cancer resistance protein (ABCG2). Eur J Med Chem 2017; 139:587-611. [PMID: 28841513 DOI: 10.1016/j.ejmech.2017.08.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/25/2017] [Accepted: 08/07/2017] [Indexed: 11/23/2022]
Abstract
Expression of ABCG2, a member of the ABC transporter superfamily, has been correlated to the clinical outcome of multiple cancers and is often associated with the occurrence of multidrug resistance (MDR) in chemotherapy. Inhibition of the transport protein by potent and selective inhibitors might be a way to treat cancer more efficiently and improve the therapy of cancer patients. Recently we reported the synthesis of new inhibitors based on a quinazoline scaffold. In the present study more structural variations were explored. Compounds with 3,4-dimethoxy groups and meta or para nitro substituents were found to be highly potent inhibitors of ABCG2. The most potent compound was more than five-fold more potent than Ko143, one of the best inhibitors of ABCG2. To determine the new compounds selectivity toward ABCG2 their inhibitory effects on ABCB1 and ABCC1 were also investigated identifying selective as well as broadspectrum inhibitors. Furthermore, intrinsic cytotoxicity and efficacy regarding the reversal of multidrug resistance toward SN-38 and mitoxantrone were explored. The most potent compounds were able to reverse the resistance toward the cytostatic agents with EC50 values below 20 nM. Additionally, the type of interaction between inhibitors and the ABCG2 substrate Hoechst 33342 was investigated yielding competitive and non-competitive interactions suggesting different modes of binding. Finally the effect of the derivatives on vanadate-sensitive ATPase activity of ABCG2 was determined. According to the different effects on ATPase activity we conclude the existence of different binding sites. This study provides the structural requirements for high potency inhibition and elucidates the interaction with ABCG2 setting the basis for further studies.
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7
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Molecular properties associated with transporter-mediated drug disposition. Adv Drug Deliv Rev 2017; 116:92-99. [PMID: 28554577 DOI: 10.1016/j.addr.2017.05.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/20/2017] [Accepted: 05/25/2017] [Indexed: 12/18/2022]
Abstract
Membrane transporters play a key role in the absorption, distribution, clearance, elimination, and transport of drugs. Understanding the drug properties and structure activity relationships (SAR) for affinity to membrane transporters is critical to optimize clearance and pharmacokinetics during drug design. To facilitate the early identification of clearance mechanism, a framework named the extended clearance classification system (ECCS) was recently introduced. Using in vitro and physicochemical properties that are readily available in early drug discovery, ECCS has been successfully applied to identify major clearance mechanism and to implicate the role of membrane transporters in determining pharmacokinetics. While the crystal structures for most of the drug transporters are currently not available, ligand-based modeling approaches that use information obtained from the structure and molecular properties of the ligands have been applied to associate the drug-related properties and transporter-mediated disposition. The approach allows prospective prediction of transporter both substrate and/or inhibitor affinity and build quantitative structure-activity relationship (QSAR) to enable early optimization of pharmacokinetics, tissue distribution and drug-drug interaction risk. Drug design applications can be further improved through uncovering transporter protein crystal structure and generation of quality data to refine and develop viable predictive models.
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Krapf MK, Gallus J, Wiese M. 4-Anilino-2-pyridylquinazolines and -pyrimidines as Highly Potent and Nontoxic Inhibitors of Breast Cancer Resistance Protein (ABCG2). J Med Chem 2017; 60:4474-4495. [PMID: 28471656 DOI: 10.1021/acs.jmedchem.7b00441] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Multidrug resistance (MDR) mediated by ATP-binding cassette (ABC) transport proteins remains a major problem in the chemotherapeutic treatment of cancer and might be overcome by inhibition of the transporter. Because of the lack of understanding, the complex mechanisms involved in the transport process, in particular for breast cancer resistance protein (BCRP/ABCG2), there is a persistent need for studies of inhibitors of ABCG2. In this study, we investigated a systematic series of 4-substituted-2-pyridylquinazolines in terms of their inhibitory potency as well as selectivity toward ABCG2. For comparison, the quinazoline scaffold was reduced to the significantly smaller 4-methylpyrimidine basic structure. Furthermore, the cytotoxicity and the ability to reverse MDR was tested with the chemotherapeutic agents SN-38 and mitoxantrone (MX). Interaction of the compounds with ABCG2 was investigated by a colorimetric ATPase assay. Enzyme kinetic studies were carried out with Hoechst 33342 as fluorescent dye and substrate of ABCG2 to elucidate the compounds binding modes.
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Affiliation(s)
- Michael K Krapf
- Pharmaceutical Institute, University of Bonn , An der Immenburg 4, 53121 Bonn, Germany
| | - Jennifer Gallus
- Pharmaceutical Institute, University of Bonn , An der Immenburg 4, 53121 Bonn, Germany
| | - Michael Wiese
- Pharmaceutical Institute, University of Bonn , An der Immenburg 4, 53121 Bonn, Germany
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Xiao L, Yi T, Chen M, Lam CWK, Zhou H. A new mechanism for increasing the oral bioavailability of scutellarin with Cremophor EL: Activation of MRP3 with concurrent inhibition of MRP2 and BCRP. Eur J Pharm Sci 2016; 93:456-67. [DOI: 10.1016/j.ejps.2016.08.054] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 08/24/2016] [Accepted: 08/28/2016] [Indexed: 01/16/2023]
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Ledwitch KV, Gibbs ME, Barnes RW, Roberts AG. Cooperativity between verapamil and ATP bound to the efflux transporter P-glycoprotein. Biochem Pharmacol 2016; 118:96-108. [PMID: 27531061 DOI: 10.1016/j.bcp.2016.08.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/12/2016] [Indexed: 12/21/2022]
Abstract
The P-glycoprotein (Pgp) transporter plays a central role in drug disposition by effluxing a chemically diverse range of drugs from cells through conformational changes and ATP hydrolysis. A number of drugs are known to activate ATP hydrolysis of Pgp, but coupling between ATP and drug binding is not well understood. The cardiovascular drug verapamil is one of the most widely studied Pgp substrates and therefore, represents an ideal drug to investigate the drug-induced ATPase activation of Pgp. As previously noted, verapamil-induced Pgp-mediated ATP hydrolysis kinetics was biphasic at saturating ATP concentrations. However, at subsaturating ATP concentrations, verapamil-induced ATPase activation kinetics became monophasic. To further understand this switch in kinetic behavior, the Pgp-coupled ATPase activity kinetics was checked with a panel of verapamil and ATP concentrations and fit with the substrate inhibition equation and the kinetic fitting software COPASI. The fits suggested that cooperativity between ATP and verapamil switched between low and high verapamil concentration. Fluorescence spectroscopy of Pgp revealed that cooperativity between verapamil and a non-hydrolyzable ATP analog leads to distinct global conformational changes of Pgp. NMR of Pgp reconstituted in liposomes showed that cooperativity between verapamil and the non-hydrolyzable ATP analog modulate each other's interactions. This information was used to produce a conformationally-gated model of drug-induced activation of Pgp-mediated ATP hydrolysis.
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Affiliation(s)
- Kaitlyn V Ledwitch
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602, United States
| | - Morgan E Gibbs
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602, United States
| | - Robert W Barnes
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602, United States
| | - Arthur G Roberts
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602, United States.
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11
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Interdomain regulation of the ATPase activity of the ABC transporter haemolysin B from Escherichia coli. Biochem J 2016; 473:2471-83. [DOI: 10.1042/bcj20160154] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 06/07/2016] [Indexed: 12/27/2022]
Abstract
Type 1 secretion systems (T1SS) transport a wide range of substrates across both membranes of Gram-negative bacteria and are composed of an outer membrane protein, a membrane fusion protein and an ABC (ATP-binding cassette) transporter. The ABC transporter HlyB (haemolysin B) is part of a T1SS catalysing the export of the toxin HlyA in E. coli. HlyB consists of the canonical transmembrane and nucleotide-binding domains. Additionally, HlyB contains an N-terminal CLD (C39-peptidase-like domain) that interacts with the transport substrate, but its functional relevance is still not precisely defined. In the present paper, we describe the purification and biochemical characterization of detergent-solubilized HlyB in the presence of its transport substrate. Our results exhibit a positive co-operativity in ATP hydrolysis. We characterized further the influence of the CLD on kinetic parameters by using an HlyB variant lacking the CLD (HlyB∆CLD). The biochemical parameters of HlyB∆CLD revealed an increased basal maximum velocity but no change in substrate-binding affinity in comparison with full-length HlyB. We also assigned a distinct interaction of the CLD and a transport substrate (HlyA1), leading to an inhibition of HlyB hydrolytic activity at low HlyA1 concentrations. At higher HlyA1 concentrations, we observed a stimulation of the hydrolytic activities of both HlyB and HlyB∆CLD, which was completely independent of the interaction of HlyA1 with the CLD. Notably, all observed effects on ATPase activity, which were also analysed in detail by mass spectrometry, were independent of the HlyA1 secretion signal. These results assign an interdomain regulatory role for the CLD modulating the hydrolytic activity of HlyB.
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Unravelling the complex drug-drug interactions of the cardiovascular drugs, verapamil and digoxin, with P-glycoprotein. Biosci Rep 2016; 36:BSR20150317. [PMID: 26823559 PMCID: PMC4793304 DOI: 10.1042/bsr20150317] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 01/22/2016] [Indexed: 02/06/2023] Open
Abstract
P-glycoprotein (Pgp) plays a major role in promoting drug–drug interactions (DDIs) with verapamil and digoxin. In the present study, we present a comprehensive molecular and mechanistic model of Pgp DDIs encompassing drug binding, ATP hydrolysis, transport and conformational changes. Drug–drug interactions (DDIs) and associated toxicity from cardiovascular drugs represents a major problem for effective co-administration of cardiovascular therapeutics. A significant amount of drug toxicity from DDIs occurs because of drug interactions and multiple cardiovascular drug binding to the efflux transporter P-glycoprotein (Pgp), which is particularly problematic for cardiovascular drugs because of their relatively low therapeutic indexes. The calcium channel antagonist, verapamil and the cardiac glycoside, digoxin, exhibit DDIs with Pgp through non-competitive inhibition of digoxin transport, which leads to elevated digoxin plasma concentrations and digoxin toxicity. In the present study, verapamil-induced ATPase activation kinetics were biphasic implying at least two verapamil-binding sites on Pgp, whereas monophasic digoxin activation of Pgp-coupled ATPase kinetics suggested a single digoxin-binding site. Using intrinsic protein fluorescence and the saturation transfer double difference (STDD) NMR techniques to probe drug–Pgp interactions, verapamil was found to have little effect on digoxin–Pgp interactions at low concentrations of verapamil, which is consistent with simultaneous binding of the drugs and non-competitive inhibition. Higher concentrations of verapamil caused significant disruption of digoxin–Pgp interactions that suggested overlapping and competing drug-binding sites. These interactions correlated to drug-induced conformational changes deduced from acrylamide quenching of Pgp tryptophan fluorescence. Also, Pgp-coupled ATPase activity kinetics measured with a range of verapamil and digoxin concentrations fit well to a DDI model encompassing non-competitive and competitive inhibition of digoxin by verapamil. The results and previous transport studies were combined into a comprehensive model of verapamil–digoxin DDIs encompassing drug binding, ATP hydrolysis, transport and conformational changes.
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Evidence for P-Glycoprotein Involvement in Cell Volume Regulation Using Coulter Sizing in Flow Cytometry. Int J Mol Sci 2015; 16:14318-37. [PMID: 26114386 PMCID: PMC4519844 DOI: 10.3390/ijms160714318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 05/06/2015] [Accepted: 05/14/2015] [Indexed: 12/13/2022] Open
Abstract
The regulation of cell volume is an essential function that is coupled to a variety of physiological processes such as receptor recycling, excitability and contraction, cell proliferation, migration, and programmed cell death. Under stress, cells undergo emergency swelling and respond to such a phenomenon with a regulatory volume decrease (RVD) where they release cellular ions, and other osmolytes as well as a concomitant loss of water. The link between P-glycoprotein, a transmembrane transporter, and cell volume regulation is controversial, and changes in cells volume are measured using microscopy or electrophysiology. For instance, by using the patch-clamp method, our team demonstrated that chloride currents activated in the RVD were more intense and rapid in a breast cancer cell line overexpressing the P-glycoprotein (P-gp). The Cell Lab Quanta SC is a flow cytometry system that simultaneously measures electronic volume, side scatter and three fluorescent colors; altogether this provides unsurpassed population resolution and accurate cell counting. Therefore, here we propose a novel method to follow cellular volume. By using the Coulter-type channel of the cytometer Cell Lab Quanta SC MPL (multi-platform loading), we demonstrated a role for the P-gp during different osmotic treatments, but also a differential activity of the P-gp through the cell cycle. Altogether, our data strongly suggests a role of P-gp in cell volume regulation.
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Tournier N, Saba W, Goutal S, Gervais P, Valette H, Scherrmann JM, Bottlaender M, Cisternino S. Influence of P-Glycoprotein Inhibition or Deficiency at the Blood-Brain Barrier on (18)F-2-Fluoro-2-Deoxy-D-glucose ( (18)F-FDG) Brain Kinetics. AAPS JOURNAL 2015; 17:652-9. [PMID: 25716150 DOI: 10.1208/s12248-015-9739-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 02/10/2015] [Indexed: 01/31/2023]
Abstract
The fluorinated D-glucose analog (18)F-2-fluoro-2-deoxy-D-glucose ((18)F-FDG) is the most prevalent radiopharmaceutical for positron emission tomography (PET) imaging. P-Glycoprotein's (P-gp, MDR1, and ABCB1) function in various cancer cell lines and tumors was shown to impact (18)F-FDG incorporation, suggesting that P-gp function at the blood-brain barrier may also modulate (18)F-FDG brain kinetics. We tested the influence of P-gp inhibition using the cyclosporine analog valspodar (PSC833; 5 μM) on the uptake of (18)F-FDG in standardized human P-gp-overexpressing cells (MDCKII-MDR1). Consequences for (18)F-FDG brain kinetics were then assessed using (i) (18)F-FDG PET imaging and suitable kinetic modelling in baboons without or with P-gp inhibition by intravenous cyclosporine infusion (15 mg kg(-1) h(-1)) and (ii) in situ brain perfusion in wild-type and P-gp/Bcrp (breast cancer resistance protein) knockout mice and controlled D-glucose exposure to the brain. In vitro, the time course of (18)F-FDG uptake in MDR1 cells was influenced by the presence of valspodar in the absence of D-glucose but not in the presence of high D-glucose concentration. PET analysis revealed that P-gp inhibition had no significant impact on estimated brain kinetics parameters K 1, k 2, k 3, V T , and CMRGlc. The lack of P-gp effect on in vivo (18)F-FDG brain distribution was confirmed in P-gp/Bcrp-deficient mice. P-gp inhibition indirectly modulates (18)F-FDG uptake into P-gp-overexpressing cells, possibly through differences in the energetic cell level state. (18)F-FDG is not a P-gp substrate at the BBB and (18)F-FDG brain kinetics as well as estimated brain glucose metabolism are influenced by neither P-gp inhibition nor P-gp/Bcrp deficiencies in baboon and mice, respectively.
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Affiliation(s)
- Nicolas Tournier
- CEA, DSV, I2BM, Service Hospitalier Frédéric Joliot, Orsay, 91406, France,
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15
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Characterization of 3-methoxy flavones for their interaction with ABCG2 as suggested by ATPase activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2929-38. [DOI: 10.1016/j.bbamem.2014.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 07/22/2014] [Accepted: 08/01/2014] [Indexed: 12/18/2022]
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16
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Zolnerciks JK, Akkaya BG, Snippe M, Chiba P, Seelig A, Linton KJ. The Q loops of the human multidrug resistance transporter ABCB1 are necessary to couple drug binding to the ATP catalytic cycle. FASEB J 2014; 28:4335-46. [PMID: 25016028 DOI: 10.1096/fj.13-245639] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
For a primary active pump, such as the human ATP-binding-cassette (ABC) transporter ABCB1, coupling of drug-binding by the two transmembrane domains (TMDs) to the ATP catalytic cycle of the two nucleotide-binding domains (NBDs) is fundamental to the transport mechanism, but is poorly understood at the biochemical level. Structure data suggest that signals are transduced through intracellular loops of the TMDs that slot into grooves on the NBDs. At the base of these grooves is the Q loop. We therefore mutated the eponymous glutamine in one or both NBD Q loops and measured the effect on conformation and function by using a conformation-sensitive antibody (UIC2) and a fluorescent drug (Bodipy-verapamil), respectively. We showed that the double mutant is trapped in the inward-open state, which binds the drug, but cannot couple to the ATPase cycle. Our data also describe marked redundancy within the transport mechanism, because single-Q-loop mutants are functional for Bodipy-verapamil transport. This result allowed us to elucidate transduction pathways from twin drug-binding cavities to the Q loops using point mutations to favor one cavity over the other. Together, the data show that the Q loop is the central flexion point where the aspect of the drug-binding cavities is coupled to the ATP catalytic cycle.
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Affiliation(s)
- Joseph K Zolnerciks
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, London UK
| | - Begum G Akkaya
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, London UK
| | - Marjolein Snippe
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, London UK
| | - Peter Chiba
- Institute of Medical Chemistry, Medical University of Vienna, Vienna, Austria; and
| | - Anna Seelig
- Biophysical Chemistry Biozentrum, University of Basel, Basel, Switzerland
| | - Kenneth J Linton
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, London UK;
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Georges E, Lian J, Laberge R. A tamoxifen derivative, N,N-diethyl-2-[4-(phenylmethyl) phenoxy] ethanamine, selectively targets P-glycoprotein-positive multidrug resistant Chinese hamster cells. Biochem Pharmacol 2014; 90:107-14. [PMID: 24821111 DOI: 10.1016/j.bcp.2014.04.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/30/2014] [Accepted: 04/30/2014] [Indexed: 02/07/2023]
Abstract
DPPE, a tamoxifen derivative with antihistamine activity, was previously shown to potentiate the toxicity of chemotherapeutic drugs. Recently, a Phase III clinical study using doxorubicin with DPPE demonstrated significant increase in the overall survival of breast cancer patients. In this study we examined the effects of DPPE alone on the growth of drug sensitive and P-gp positive CHO cell line. Our results demonstrate DPPE is selectively toxic to P-gp positive cells and the sensitivity to DPPE alone correlated with the levels of P-gp expression. Moreover, in MDR cells, DPPE-induced apoptosis was significantly reduced with Bcl2 overexpression and in the presence of P-gp ATPase inhibitor, PSC833. Furthermore, knockdown of P-gp expression in MDR cells with P-gp-siRNA reversed DPPE sensitivity and increased their sensitivity to doxorubicin and taxol but not to cisplatin. The addition of DPPE to membrane fractions led to dose-dependent increase in P-gp ATPase that was inhibited with PSC833. Moreover, incubation of P-gp positive cells with DPPE led to a significant increase in superoxide levels and a drop in cellular ATP and GSH pools that were reversible with inhibitors of P-gp ATPase. The combined presence of DPPE and the mitochondria electron transport complex III inhibitor, antimycin A, synergized in their effects on the growth of MDR cells but had no effect on the growth of parental drug sensitive cells. Collectively, the results of this study provide a possible mechanism that may be relevant to the clinical results of DPPE in breast cancer trial and demonstrates DPPE as P-gp collateral sensitivity drug.
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Affiliation(s)
- Elias Georges
- Institute of Parasitology, McGill University, Macdonald Campus, Ste. Anne de Bellevue (Montreal), Quebec, Canada H9X-3V9.
| | - Jing Lian
- Institute of Parasitology, McGill University, Macdonald Campus, Ste. Anne de Bellevue (Montreal), Quebec, Canada H9X-3V9
| | - Remi Laberge
- Institute of Parasitology, McGill University, Macdonald Campus, Ste. Anne de Bellevue (Montreal), Quebec, Canada H9X-3V9
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18
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The cellular labeling and pH-sensitive responsive-drug release of celastrol in cancer cells based on Cys-CdTe QDs. Sci China Chem 2014. [DOI: 10.1007/s11426-014-5092-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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19
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Figueira-Mansur J, Ferreira-Pereira A, Mansur JF, Franco TA, Alvarenga ESL, Sorgine MHF, Neves BC, Melo ACA, Leal WS, Masuda H, Moreira MF. Silencing of P-glycoprotein increases mortality in temephos-treated Aedes aegypti larvae. INSECT MOLECULAR BIOLOGY 2013; 22:648-658. [PMID: 23980723 DOI: 10.1111/imb.12052] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Re-emergence of vector-borne diseases such as dengue and yellow fever, which are both transmitted by the Aedes aegypti mosquito, has been correlated with insecticide resistance. P-glycoproteins (P-gps) are ATP-dependent efflux pumps that are involved in the transport of substrates across membranes. Some of these proteins have been implicated in multidrug resistance (MDR). In this study, we identified a putative P-glycoprotein in the Ae. aegypti database based on its significantly high identity with Anopheles gambiae, Culex quinquefasciatus, Drosophila melanogaster and human P-gps. The basal ATPase activity of ATP-binding cassette transporters in larvae was significantly increased in the presence of MDR modulators (verapamil and quinidine). An eightfold increase in Ae. aegypti P-gp (AaegP-gp) gene expression was detected in temephos-treated larvae as determined by quantitative PCR. To analyse the potential role of AaegP-gp in insecticide efflux, a temephos larvicide assay was performed in the presence of verapamil. The results showed an increase of 24% in temephos toxicity, which is in agreement with the efflux reversing effect. RNA interference (RNAi)-mediated silencing of the AaegP-gp gene caused a significant increase in temephos toxicity (57%). In conclusion, we have demonstrated for the first time in insects that insecticide-induced P-gp expression can be involved in the modulation of insecticide efflux.
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Affiliation(s)
- J Figueira-Mansur
- Universidade Federal do Rio de Janeiro, Instituto de Química, Rio de Janeiro, RJ, Brazil; Universidade Federal do Rio de Janeiro, Instituto de Bioquímica Médica, Programa de Biologia Molecular e Biotecnologia, Rio de Janeiro, RJ, Brazil
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Rauch C, Paine SW, Littlewood P. Can long range mechanical interaction between drugs and membrane proteins define the notion of molecular promiscuity? Application to P-glycoprotein-mediated multidrug resistance (MDR). Biochim Biophys Acta Gen Subj 2013; 1830:5112-8. [PMID: 23850561 DOI: 10.1016/j.bbagen.2013.06.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 06/17/2013] [Accepted: 06/30/2013] [Indexed: 01/26/2023]
Abstract
BACKGROUND Failure of treatment in over 90% of patients with metastatic cancer is due to acquired MDR. P-glycoprotein (Pgp) remains the archetypal drug membrane transporter expressed in many MDR cancer cells. Albeit the ATPase activity of Pgp is triggered by the presence of drug in the membrane, it is commonly assumed that when two drug molecules meet the same Pgp the protein cannot handle them efficiently due to steric effects and as a result the ATPase activity drops. However it is also possible that drug accumulating in the lipid-phase may affect the membrane in such a way that it imposes the mechanical closure of transporters by opposing the force mediated by ATP consumption. In this context, long range interactions between drug and membrane proteins could exist. METHODS Recent data concerning Pgp structure have allowed us to formalize this hypothesis and we present a physico-mathematical model that is not based on predictive QSAR or other empirical methods applied to experimental data. RESULTS Long range mechanical interactions between Pgp and drugs are predicted to occur at an external concentration of drug ~10-100μM as previously determined experimentally at which concentration ~50% of transporters should be rendered inactive. CONCLUSION Distance interaction(s) between Pgp and drugs exist explaining an ill-defined effect concerning the ability of any drug to inhibit Pgp once a threshold concentration in the membrane has been reached. GENERAL SIGNIFICANCE Potential application of the theory in the field of pharmacology concentrating on the notion of molecular promiscuity and toxicity in drug discovery prediction is discussed.
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Affiliation(s)
- Cyril Rauch
- School of Veterinary Medicine and Science, University of Nottingham, College Road, Sutton Bonington, LE12 5RD, UK.
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21
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Fischer S, Klüver N, Burkhardt-Medicke K, Pietsch M, Schmidt AM, Wellner P, Schirmer K, Luckenbach T. Abcb4 acts as multixenobiotic transporter and active barrier against chemical uptake in zebrafish (Danio rerio) embryos. BMC Biol 2013; 11:69. [PMID: 23773777 PMCID: PMC3765700 DOI: 10.1186/1741-7007-11-69] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 06/07/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In mammals, ABCB1 constitutes a cellular "first line of defense" against a wide array of chemicals and drugs conferring cellular multidrug or multixenobiotic resistance (MDR/MXR). We tested the hypothesis that an ABCB1 ortholog serves as protection for the sensitive developmental processes in zebrafish embryos against adverse compounds dissolved in the water. RESULTS Indication for ABCB1-type efflux counteracting the accumulation of chemicals in zebrafish embryos comes from experiments with fluorescent and toxic transporter substrates and inhibitors. With inhibitors present, levels of fluorescent dyes in embryo tissue and sensitivity of embryos to toxic substrates were generally elevated. We verified two predicted sequences from zebrafish, previously annotated as abcb1, by cloning; our synteny analyses, however, identified them as abcb4 and abcb5, respectively. The abcb1 gene is absent in the zebrafish genome and we explored whether instead Abcb4 and/or Abcb5 show toxicant defense properties. Quantitative real-time polymerase chain reaction (qPCR) analyses showed the presence of transcripts of both genes throughout the first 48 hours of zebrafish development. Similar to transporter inhibitors, morpholino knock-down of Abcb4 increased accumulation of fluorescent substrates in embryo tissue and sensitivity of embryos toward toxic compounds. In contrast, morpholino knock-down of Abcb5 did not exert this effect. ATPase assays with recombinant protein obtained with the baculovirus expression system confirmed that dye and toxic compounds act as substrates of zebrafish Abcb4 and inhibitors block its function. The compounds tested comprised model substrates of human ABCB1, namely the fluorescent dyes rhodamine B and calcein-am and the toxic compounds vinblastine, vincristine and doxorubicin; cyclosporin A, PSC833, MK571 and verapamil were applied as inhibitors. Additionally, tests were performed with ecotoxicologically relevant compounds: phenanthrene (a polycyclic aromatic hydrocarbon) and galaxolide and tonalide (two polycyclic musks). CONCLUSIONS We show that zebrafish Abcb4 is a cellular toxicant transporter and provides protection of embryos against toxic chemicals dissolved in the water. Zebrafish Abcb4 thus is functionally similar to mammalian ABCB1, but differs from mammalian ABCB4, which is not involved in cellular resistance to chemicals but specifically transports phospholipids in the liver. Our data have important implications: Abcb4 could affect bioavailability - and thus toxicologic and pharmacologic potency - of chemicals to zebrafish embryos and inhibition of Abcb4 therefore causes chemosensitization, that is, enhanced sensitivity of embryos to toxicants. These aspects should be considered in (eco)toxicologic and pharmacologic chemical screens with the zebrafish embryo, a major vertebrate model.
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Affiliation(s)
- Stephan Fischer
- Department of Bioanalytical Ecotoxicology, UFZ - Helmholtz Centre for Environmental Research, 04318 Leipzig, Germany.
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22
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Li J, Chen C, Wang X, Gu Z, Chen B. Novel Strategy to Fabricate PLA/Au Nanocomposites as an Efficient Drug Carrier for Human Leukemia Cells in Vitro. NANOSCALE RESEARCH LETTERS 2011; 6:29. [PMID: 27502652 PMCID: PMC3211355 DOI: 10.1007/s11671-010-9762-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Accepted: 08/14/2010] [Indexed: 05/24/2023]
Abstract
Poly (lactic acid) (PLA) polymer has the promising applications in the biomedical field because of its biodegradability and safe elimination. In this study, we have explored the bio-application of new nanocomposites composed with PLA nanofibers and Au nanoparticles as the potential drug carrier for an efficient drug delivery in target cancer cells. The results demonstrated that the anticancer drug daunorubicin could be efficiently self-assembled on the surface of PLA/Au nanocomposites and the synergistic enhancement of PLA/Au nanocomposites conjugated with daunorubicin into drug-sensitive K562 and drug-resistant leukemia K562/AO2 cells could be obviously observed by MTT assay and confocal fluorescence microscopy studies. These observations suggest that the new nanocomposites could readily induce daunorubicin to accumulate and uptake in target leukemia cells and increase the drug's cytotoxicity. Especially, the PLA/Au nanocomposites could significantly facilitate the cellular drug absorbtion of daunorubicin into drug-resistant K562/AO2 cells and efficiently inhibit the cancer cell proliferation. This raised the possibility to utilize the PLA/Au nanocomposites as a new effective additive agent to inhibit the drug resistance and thus as a novel strategy to sensitively track the respective cancer cells.
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Affiliation(s)
- Jingyuan Li
- State Key Lab of Bioelectronics (Chien-Shiung WU Laboratory), Southeast University, 210096, Nanjing, China
| | - Chen Chen
- State Key Lab of Bioelectronics (Chien-Shiung WU Laboratory), Southeast University, 210096, Nanjing, China
| | - Xuemei Wang
- State Key Lab of Bioelectronics (Chien-Shiung WU Laboratory), Southeast University, 210096, Nanjing, China.
| | - Zhongze Gu
- State Key Lab of Bioelectronics (Chien-Shiung WU Laboratory), Southeast University, 210096, Nanjing, China
| | - Baoan Chen
- Department of Hematology, Zhongda Hospital, Southeast University, 210096, Nanjing, China
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Husted S, Søkilde R, Rask L, Cirera S, Busk PK, Eriksen J, Litman T. MicroRNA expression profiles associated with development of drug resistance in Ehrlich ascites tumor cells. Mol Pharm 2011; 8:2055-62. [PMID: 21899346 DOI: 10.1021/mp200255d] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Multidrug resistance (MDR) poses a major obstacle to successful chemotherapeutic treatment of cancer, and often involves multiple genes, which may be regulated post-transcriptionally by microRNAs (miRNAs). The purpose of the present study was therefore to identify any resistance-associated changes in miRNA expression in a sensitive and five increasingly drug-resistant Ehrlich ascites tumor (EAT) cell lines, representing different steps in the development of resistance. We used an LNA-enhanced microarray platform to study the global miRNA expression profiles in the six murine EAT cell lines, and identified growth-, hypoxia-, and resistance-specific miRNA patterns. Among the differentially expressed miRNAs, we found the two clusters miR-183∼miR-96∼miR-182 and miR-200b∼miR-200a∼miR-429 as well as miR-141 to be consistently upregulated in the MDR cell lines, while miR-125b-5p and the two clusters miR-30d∼miR-30b and miR-23b∼miR-27b∼miR-24-1 were downregulated in most of the resistant EAT cells. Several of the target genes for these miRNAs-including Zeb1/Zeb2 and members of the Fox gene family-could contribute to the drug-resistant phenotype, although we did not find that the degree of resistance was directly correlated to any specific changes in miRNA expression. Probably, the observed miRNA expression patterns reflect the underlying genomic instability of the tumor cells, and further studies are needed to explore how the highly complex regulatory miRNA networks contribute to the development of MDR.
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Affiliation(s)
- Susanne Husted
- Department of Oncology, Herlev Hospital, University of Copenhagen, Herlev, Denmark
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24
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Rauch C. The “Multi” of Drug Resistance Explained by Oscillating Drug Transporters, Drug–Membrane Physical Interactions and Spatial Dimensionality. Cell Biochem Biophys 2011; 61:103-13. [DOI: 10.1007/s12013-011-9166-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Mason CW, Hassan HE, Kim KP, Cao J, Eddington ND, Newman AH, Voulalas PJ. Characterization of the transport, metabolism, and pharmacokinetics of the dopamine D3 receptor-selective fluorenyl- and 2-pyridylphenyl amides developed for treatment of psychostimulant abuse. J Pharmacol Exp Ther 2010; 333:854-64. [PMID: 20228156 PMCID: PMC2879935 DOI: 10.1124/jpet.109.165084] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 03/11/2010] [Indexed: 11/22/2022] Open
Abstract
The recent discovery of novel high-affinity and selective dopamine D3 receptor (DA D3R) antagonists and partial agonists has provided tools with which to further elucidate the role DA D3R plays in substance abuse. The present study was conducted to evaluate the transport, metabolism, pharmacokinetics, and brain uptake of the DA D3R-selective fluorenyl amides, NGB 2904 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-9H-fluorene-2-carboxamide] fumarate) and JJC 4-077 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)-3-hydroxybutyl)-9H-fluorene-2-carboxamide hydrochloride], and the 2-pyridylphenyl amides, CJB 090 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-4-(pyridine-2-yl)benzamide hydrochloride] and PG 01037 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)-trans-but-2-enyl)-4-(pyridine-2-yl)benzamide hydrochloride], all of which have been studied in animal models of psychostimulant abuse. Additional screening with a panel of human and rat Supersomes was performed for NGB 2904 and PG 01037. Drug-stimulated ATPase activation assays and bidirectional transport and efflux assays were used to test for substrate specificity of NGB 2904 and PG 01037 for human and rat efflux transporters. All compounds exhibited moderate elimination half-lives, ranging from 1.49 to 3.27 h, and large volumes of distribution (5.95-14.19 l/kg). The brain-to-plasma ratios ranged from 2.93 to 11.81 and were higher than those previously reported for cocaine. Brain exposure levels of NGB 2904 and PG 01037 were significantly reduced after intraperitoneal administration compared with intravenous administration. The metabolism of these compounds was mediated primarily by CYP3A subfamilies. PG 01037 was a P-glycoprotein-transported substrate. Higher doses of these compounds are often required for in vivo action, suggesting decreased bioavailability via extravascular administration that may be attributed to high drug efflux and hepatic metabolism. These studies provide important preclinical information for optimization of next-generation D3R selective agents for the treatment of drug addiction.
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Affiliation(s)
- Clifford W Mason
- Pharmacokinetics-Biopharmaceutics Laboratory, Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201, USA
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Poulsen KA, Andersen EC, Hansen CF, Klausen TK, Hougaard C, Lambert IH, Hoffmann EK. Deregulation of apoptotic volume decrease and ionic movements in multidrug-resistant tumor cells: role of chloride channels. Am J Physiol Cell Physiol 2010; 298:C14-25. [DOI: 10.1152/ajpcell.00654.2008] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Changes in cell volume and ion gradients across the plasma membrane play a pivotal role in the initiation of apoptosis. Here we explore the kinetics of apoptotic volume decrease (AVD) and ion content dynamics in wild-type (WT) and multidrug-resistant (MDR) Ehrlich ascites tumor cells (EATC). In WT EATC, induction of apoptosis with cisplatin (5 μM) leads to three distinctive AVD stages: an early AVD1 (4–12 h), associated with a 30% cell water loss; a transition stage AVDT (∼12 to 32 h), where cell volume is partly recovered; and a secondary AVD2 (past 32 h), where cell volume was further reduced. AVD1 and AVD2 were coupled to net loss of Cl−, K+, Na+, and amino acids (ninhydrin-positive substances), whereas during AVDT, Na+ and Cl− were accumulated. MDR EATC was resistant to cisplatin, showing increased viability and less caspase 3 activation. Compared with WT EATC, MDR EATC underwent a less pronounced AVD1, an augmented AVDT, and a delay in induction of AVD2. Changes in AVD were associated with inhibition of Cl− loss during AVD1, augmented NaCl uptake during AVDT, and a delay of Cl− loss during AVD2. Application of the anion channel inhibitor NS3728 inhibited AVD and completely abolished the differences in AVD, ionic movements, and caspase 3 activation between WT and MDR EATC. Finally, the maximal capacity of volume-regulated anion channel was found to be strongly repressed in MDR EATC. Together, these data suggest that impairment of AVD, primarily via modulation of NaCl movements, contribute to protection against apoptosis in MDR EATC.
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Affiliation(s)
- K. A. Poulsen
- Department of Biology, University of Copenhagen, Copenhagen; and
| | - E. C. Andersen
- Department of Biology, University of Copenhagen, Copenhagen; and
| | - C. F. Hansen
- Department of Biology, University of Copenhagen, Copenhagen; and
| | - T. K. Klausen
- Department of Biology, University of Copenhagen, Copenhagen; and
| | | | - I. H. Lambert
- Department of Biology, University of Copenhagen, Copenhagen; and
| | - E. K. Hoffmann
- Department of Biology, University of Copenhagen, Copenhagen; and
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Glavinas H, Méhn D, Jani M, Oosterhuis B, Herédi-Szabó K, Krajcsi P. Utilization of membrane vesicle preparations to study drug-ABC transporter interactions. Expert Opin Drug Metab Toxicol 2008; 4:721-32. [PMID: 18611113 DOI: 10.1517/17425255.4.6.721] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND The last 15 years have marked an expansion in our understanding of how ABC transporters modulate the pharmacokinetic properties of drugs. Assays based on different membrane preparations were one of the first methods developed to study ABC transporters. Later, they turned out to be valuable tools to gain insight into the nature of drug-ABC transporter interactions. OBJECTIVES Membranes prepared from different sources have been used and characterized; based on the biochemical characteristics of the transport process, a number of different assay types have been developed. METHODS This review focuses on the current experiences on how different membrane-based assays can be utilized in pharmaceutical R&D. Sources of membrane preparations, available assay types and correlation studies between different in-vitro and in-vivo methods are discussed. RESULTS/CONCLUSION Membrane-based assays are valuable tools in drug discovery to characterize drug-ABC transporter interactions.
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von Richter O, Glavinas H, Krajcsi P, Liehner S, Siewert B, Zech K. A novel screening strategy to identify ABCB1 substrates and inhibitors. Naunyn Schmiedebergs Arch Pharmacol 2008; 379:11-26. [PMID: 18758752 DOI: 10.1007/s00210-008-0345-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 08/04/2008] [Indexed: 12/19/2022]
Abstract
We tested the hypothesis whether data on ABCB1 ATPase activity and passive permeability can be used in combination to identify ABCB1 substrates and inhibitors. We determined passive permeability using an artificial membrane permeability assay (HDM-PAMPA) and ABCB1 function, i.e., vanadate-sensitive ATPase activity for a training set (40 INN drugs) and a validation set (26 development compounds). In parallel experiments, we determined ABCB1 function, i.e., vectorial transport in a Caco-2 cell monolayer, and ABCB1 inhibition, i.e., calcein AM extrusion out of K562-MDR cells, to cross-validate the results with cellular assays. We found that compounds that did not modulate ABCB1-ATPase did also not affect calcein AM extrusion and were not actively transported by ABCB1 in Caco-2 cell monolayers. The results corroborated the effect of passive permeability as an important covariate of active transport: active transport in Caco-2 monolayer was only apparent for compounds showing low passive permeability (<5.0 cmx10(-6)/s) in the HDM-PAMPA assay whereas compounds with high passive permeability (>50 cmx10(-6)/s) were shown to inhibit calcein AM efflux with IC50 values close to their respective Km value obtained for ABCB1-ATPase. The use of HDM-PAMPA in combination with ABCB1-ATPase offers a simple, inexpensive experimental approach capable of identifying ABCB1 inhibitors as well as transported substrates.
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Affiliation(s)
- Oliver von Richter
- Division of Drug Metabolism and Pharmacokinetics, Altana Pharma AG, Konstanz, Germany.
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29
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Song M, Guo D, Pan C, Jiang H, Chen C, Zhang R, Gu Z, Wang X. The application of poly(N-isopropylacrylamide)-co-polystyrene nanofibers as an additive agent to facilitate the cellular uptake of an anticancer drug. NANOTECHNOLOGY 2008; 19:165102. [PMID: 21825633 DOI: 10.1088/0957-4484/19/16/165102] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In this paper, we have fabricated poly(N-isopropylacrylamide)-co-polystyrene (PNIPAM-co-PS) nanofibers by electrospinning and explored the possibility to utilize the PNIPAM-co-PS nanofibers to enhance the permeation and uptake of the anticancer drug daunorubicin in drug-sensitive and drug-resistant leukemia K562 cells. Our MTT assay and electrochemical studies demonstrate that PNIPAM-co-PS nanofibers could play an important role in facilitating the cell track and drug delivery to the cancer cells. Meanwhile, the observations of atomic force microscopy (AFM) and confocal fluorescence microscopy indicate that the relevant interaction of the PNIPAM-co-PS nanofibers with bioactive molecules on the membrane of leukemia cell lines could affect the intracellular drug uptake positively and lead to the efficient accumulation of daunorubicin in drug-sensitive and drug-resistant cancer cells.
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Affiliation(s)
- Min Song
- State Key Lab of Bioelectronics, Chien-Shiung Wu Laboratory, Southeast University, Nanjing 210096, People's Republic of China
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30
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Seelig A. The Role of Size and Charge for Blood–Brain Barrier Permeation of Drugs and Fatty Acids. J Mol Neurosci 2007; 33:32-41. [PMID: 17901543 DOI: 10.1007/s12031-007-0055-y] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/29/2022]
Abstract
The lipid bilayer is the diffusion barrier of biological membranes. Highly protective membranes such as the blood-brain barrier (BBB) are reinforced by ABC transporters such as P-glycoprotein (MDR1, ABCB1) and multidrug resistance associated proteins (MRPs, ABCCs). The transporters bind their substrates in the cytosolic lipid bilayer leaflet before they reach the cytosol and flip them to the outer leaflet. The large majority of drugs targeted to the central nervous system (CNS) are intrinsic substrates of these transporters. Whether an intrinsic substrate can cross the BBB depends on whether passive influx is higher than active efflux. In this paper, we show that passive influx can be estimated quantitatively on the basis of Stokesian diffusion, taking into account the ionization constant and the cross-sectional area of the molecule in its membrane bond conformation, as well as the lateral packing density of the membrane. Active efflux by ABC transporters was measured. The calculated net flux is in excellent agreement with experimental results. The approach is exemplified with several drugs and fatty acid analogs. It shows that compounds with small cross-sectional areas (A(D) < 70 A(2)) and/or intermediate or low charge exhibit higher passive influx than efflux and, therefore, cross the BBB despite being intrinsic substrates. Large (A(D) > 70 A(2)) or highly charged compounds show higher efflux than influx. They cannot cross the BBB and are, thus, apparent substrates for ABC transporters. The strict size and charge limitation for BBB permeation results from the synergistic interaction between passive influx and active efflux.
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Affiliation(s)
- Anna Seelig
- Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 70, Basel, Switzerland.
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Shirasaka Y, Onishi Y, Sakurai A, Nakagawa H, Ishikawa T, Yamashita S. Evaluation of human P-glycoprotein (MDR1/ABCB1) ATPase activity assay method by comparing with in vitro transport measurements: Michaelis-Menten kinetic analysis to estimate the affinity of P-glycoprotein to drugs. Biol Pharm Bull 2007; 29:2465-71. [PMID: 17142983 DOI: 10.1248/bpb.29.2465] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human ABC transporter P-glycoprotein (P-gp/ABCB1) encoded by the multidrug resistance (MDR1) gene is recognized as one of the most important factors regulating pharmacokinetics of a number of clinically important drugs because of its function of extruding a wide range of structurally unrelated amphiphilic and hydrophobic drugs from the inside to the outside of cells in an ATP-driven mechanism. In the present study, we have evaluated the high-speed ATPase activity assay method by comparing with in vitro transport assay systems using MDR1-transfected MDR1-MDCK cells. Since substrate drugs were found to interfere with the photometric detection of inorganic phosphate (Pi) that was liberated according to the hydrolysis of ATP to ADP in ATPase activity assay, at first, a method in which the amount of Pi can be calculated correctly. Results demonstrate that the kinetic parameters obtained in ATPase activity assay are not necessarily correspond with those in in vitro transport assay, suggesting that these methods might detect the different processes of drug-P-gp interaction. The combining of the ATPase activity assay and in vitro transport technologies provides us the insight into mechanisms of the membrane transport of drugs by P-gp.
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Zhang R, Wang X, Wu C, Song M, Li J, Lv G, Zhou J, Chen C, Dai Y, Gao F, Fu D, Li X, Guan Z, Chen B. Synergistic enhancement effect of magnetic nanoparticles on anticancer drug accumulation in cancer cells. NANOTECHNOLOGY 2006; 17:3622-3626. [PMID: 19661614 DOI: 10.1088/0957-4484/17/14/043] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Three kinds of magnetic nanoparticle, tetraheptylammonium capped nanoparticles of Fe(3)O(4), Fe(2)O(3) and Ni have been synthesized, and the synergistic effect of these nanoparticles on the drug accumulation of the anticancer drug daunorubicin in leukaemia cells has been explored. Our observations indicate that the enhancement effect of Fe(3)O(4) nanoparticles is much stronger than that of Fe(2)O(3) and Ni nanoparticles, suggesting that nanoparticle surface chemistry and size as well as the unique properties of the magnetic nanoparticles themselves may contribute to the synergistic enhanced effect of the drug uptake of targeted cancer cells.
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Affiliation(s)
- Renyun Zhang
- State Key Lab of Bioelectronics, Chien-Shiung Wu Laboratory, Southeast University, Nanjing 210096, People's Republic of China
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Park SJ, Wu CH, Choi MR, Najafi F, Emami A, Safa AR. P-glycoprotein enhances TRAIL-triggered apoptosis in multidrug resistant cancer cells by interacting with the death receptor DR5. Biochem Pharmacol 2006; 72:293-307. [PMID: 16753135 DOI: 10.1016/j.bcp.2006.04.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Revised: 04/17/2006] [Accepted: 04/19/2006] [Indexed: 11/17/2022]
Abstract
The death-inducing cytokine TRAIL is a promising agent for anticancer therapy since it preferentially kills cancer versus normal cells; however, some cancer cells are TRAIL-resistant. We initially explored whether overexpression of the MDR1 gene product P-glycoprotein (P-gp), which causes multidrug resistance (MDR) in cancer cells, also contributes to TRAIL-resistance. Surprisingly, our results revealed that P-gp-overexpression enhances TRAIL-induced apoptosis not only in neoplastic cells transfected with the MDR1 gene but also in MDR variants selected with cytotoxic anticancer agents. Mechanistic analysis of TRAIL-induced apoptosis in the MDR1-transfected MCF-7 breast cancer cell line BC-19 revealed that TRAIL-triggered significantly more apoptosis in these cells compared with parental MCF-7 cells by binding to the TRAIL receptor DR5. DR5 but not DR4 engagement by TRAIL attenuated cellular ATP levels by robustly stimulating P-gp ATPase activity, and thus triggered P-gp-dependent apoptosis by depletion of the cellular ATP pool. In addition to hyperactive P-gp-mediated ATP hydrolysis, TRAIL-induced, P-gp-potentiated apoptosis was associated with activation of caspases-6, -7, -8, and -9; Bid cleavage; and mitochondrial depolarization. P-gp interacted with the TRAIL receptors DR4, DR5, and DcR1 in plasma membranes and enhanced TRAIL binding to DR5. Interestingly, the decreased level of the decoy TRAIL receptor, DcR1, in BC-19 cells further sensitized these cells to TRAIL. Therefore, both extrinsic and intrinsic apoptosis pathways are involved in this process. These findings for the first time reveal that TRAIL treatment preferentially causes apoptosis in P-gp-overexpressing MDR cells, and suggests significant clinical implications for the use of TRAIL in treating neoplasms that have failed chemotherapy.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Adenosine Triphosphate/metabolism
- Antibodies/pharmacology
- Antineoplastic Agents/pharmacology
- Apoptosis/drug effects
- Apoptosis Regulatory Proteins/metabolism
- Apoptosis Regulatory Proteins/pharmacology
- Caspase 8
- Caspases/metabolism
- Cell Line, Tumor
- Cytochromes c/metabolism
- Dose-Response Relationship, Drug
- Doxorubicin/pharmacology
- Drug Resistance, Multiple/genetics
- Drug Resistance, Neoplasm/genetics
- Enzyme Activation/drug effects
- Humans
- Membrane Glycoproteins/metabolism
- Membrane Glycoproteins/pharmacology
- Membrane Potentials/drug effects
- Mitochondrial Membranes/drug effects
- Mitochondrial Membranes/physiology
- Paclitaxel/pharmacology
- Protein Binding
- Receptors, TNF-Related Apoptosis-Inducing Ligand
- Receptors, Tumor Necrosis Factor/immunology
- Receptors, Tumor Necrosis Factor/metabolism
- TNF-Related Apoptosis-Inducing Ligand
- Transfection
- Tumor Necrosis Factor-alpha/metabolism
- Tumor Necrosis Factor-alpha/pharmacology
- Vinblastine/pharmacology
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Affiliation(s)
- Soo-Jung Park
- Department of Pharmacology and Toxicology, Indiana University Cancer Center, 1044 West Walnut R4-119, Indianapolis, 46202, USA
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Wesołowska O, Mosiadz D, Motohashi N, Kawase M, Michalak K. Phenothiazine maleates stimulate MRP1 transport activity in human erythrocytes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1720:52-8. [PMID: 16364236 DOI: 10.1016/j.bbamem.2005.11.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Revised: 10/31/2005] [Accepted: 11/10/2005] [Indexed: 11/18/2022]
Abstract
The expression of multidrug resistance-associated protein (MRP1) results in ATP-dependent reduction of drugs' concentration in cancer cells, i.e., multidrug resistance (MDR). Since the majority of projects are concentrated on the search of the new MDR modulators, there are very few reports on drug-induced stimulation of MDR transporters activity. In the present work, by means of functional fluorescence assay we have shown that MRP1-mediated efflux of 2',7'-bis-(3-carboxypropyl)-5-(and-6)-carboxyfluorescein (BCPCF) out of human erythrocytes is stimulated by phenothiazine maleates that have been already identified as P-glycoprotein inhibitors. Phenothiazine maleates-induced stimulation of ATP-dependent uptake of 2',7'-bis-(3-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF) into inside-out membrane vesicles prepared from erythrocyte membranes has been also demonstrated. Moreover, it was shown that phenothiazine maleates exerted stimulating effect on ATPase activity measured in erythrocyte membranes. To our best knowledge, this report is the first one demonstrating that compounds able to inhibit transport activity of P-glycoprotein can stimulate MRP1 transporter. We conclude that phenothiazine maleates probably exert their stimulatory effect on MRP1 by direct interaction with the protein at the site different from the substrate binding site.
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Affiliation(s)
- Olga Wesołowska
- Department of Biophysics, Wrocław Medical University, ul. Chałubińskiego 10, 50-368 Wrocław, Poland.
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35
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Batrakova EV, Li S, Li Y, Alakhov VY, Kabanov AV. Effect of pluronic P85 on ATPase activity of drug efflux transporters. Pharm Res 2005; 21:2226-33. [PMID: 15648254 PMCID: PMC2677181 DOI: 10.1007/s11095-004-7675-5] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE Pluronic block copolymers are potent sensitizers of multi-drug resistant (MDR) cancer cells. The sensitization effect by Pluronics is a result of two processes acting in concert: i) intracellular ATP depletion, and ii) inhibition of ATPase activity of drug efflux proteins. This work characterizes effects of Pluronic P85 on ATPase activities of Pgp, MRP1, and MRP2 drug efflux transport proteins and interaction of these proteins with their substrates, vinblastine, and leucotriene C4. METHODS Using membranes overexpressing Pgp, MRP1, and MRP2, the current study evaluates effects of Pluronic P85 (P85) on the kinetic parameters (Vmax, Km, Vmax/Km) of ATP hydrolysis by these ATPases. RESULTS The decreases in the maximal reaction rates (Vmax) and increases in apparent Michaelis constants (Km) for these transporters in the presence of various concentrations of P85 were observed. The mechanism of these effects may involve i) conformational changes of the transporter due to membrane fluidization and/or ii) nonspecific steric hindrance of the drug-binding sites by P85 chains embedded into cellular membranes. The extent of these alterations was increased in the row MRP1 < MRP2 << Pgp. CONCLUSIONS These data suggest that there are unifying pathways for the inhibition of Pgp and MRPs by the block copolymer. However, the effect of P85 on Pgp ATPase activity is considerably greater compared with the effects on MRP1 and MRP2 ATPases. This may be a reason for greater inhibitory effects of Pluronic in Pgp- compared with MRP-overexpressing cells.
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Affiliation(s)
- Elena V. Batrakova
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 985830 Nebraska Medical Center, Omaha, Nebraska 68198-5830, USA
| | - Shu Li
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 985830 Nebraska Medical Center, Omaha, Nebraska 68198-5830, USA
| | - Yili Li
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 985830 Nebraska Medical Center, Omaha, Nebraska 68198-5830, USA
| | - Valery Yu. Alakhov
- Supratek Pharma Inc., 215, boulevard Bouchard #1315, Dorval, Quebec, Canada H9S 1A9
| | - Alexander V. Kabanov
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 985830 Nebraska Medical Center, Omaha, Nebraska 68198-5830, USA
- To whom correspondence should be addressed. (e-mail: )
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36
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Henriksen U, Gether U, Litman T. Effect of Walker A mutation (K86M) on oligomerization and surface targeting of the multidrug resistance transporter ABCG2. J Cell Sci 2005; 118:1417-26. [PMID: 15769853 DOI: 10.1242/jcs.01729] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ATP binding cassette (ABC) half-transporter ABCG2 (MXR/BCRP/ABCP) is associated with mitoxantrone resistance accompanied by cross-resistance to a broad spectrum of cytotoxic drugs. Here we investigate the functional consequences of mutating a highly conserved lysine in the Walker A motif of the nucleotide binding domain (NBD) known to be critical for ATP binding and/or hydrolysis in ABC transporters. The mutant (ABCG2-K86M) was inactive as expected but was expressed at similar levels as the wild-type (wt) protein. The mutation did not affect the predicted oligomerization properties of the transporter; hence, co-immunoprecipitation experiments using differentially tagged transporters showed evidence for oligomerization of both ABCG2-wt and of ABCG2-wt with ABCG2-K86M. We also obtained evidence that both ABCG2-wt and ABCG2-K86M exist in the cells as disulfide-linked dimers. Moreover, measurement of prazosin-stimulated ATPase activity revealed a dominant-negative effect of ABCG2-K86M on ABCG2-wt function in co-transfected HEK293 cells. This is consistent with the requirement for at least two active NBDs for transporter activity and suggests that the transporter is a functional dimer. Finally, we analyzed targeting of ABCG2-wt and ABCG2-K86M and observed that they localize to two distinct subcellular compartments: ABCG2-wt targets the cell surface whereas ABCG2-K86M is targeted to the Golgi apparatus followed by retrieval to the endoplasmic reticulum. This suggests an as yet unknown role of the NBDs in assisting proper surface targeting of ABC transporters.
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Affiliation(s)
- Ulla Henriksen
- Molecular Neuropharmacology Group, Department of Pharmacology, The Panum Institute, Blegdamsvej 3, University of Copenhagen, DK-2200 Copenhagen, Denmark
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Al-Shawi MK, Polar MK, Omote H, Figler RA. Transition state analysis of the coupling of drug transport to ATP hydrolysis by P-glycoprotein. J Biol Chem 2003; 278:52629-40. [PMID: 14551217 DOI: 10.1074/jbc.m308175200] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATPase activity associated with P-glycoprotein (Pgp) is characterized by three drug-dependent phases: basal (no drug), drug-activated, and drug-inhibited. To understand the communication between drug-binding sites and ATP hydrolytic sites, we performed steady-state thermodynamic analyses of ATP hydrolysis in the presence and absence of transport substrates. We used purified human Pgp (ABCB1, MDR1) expressed in Saccharomyces cerevisiae (Figler, R. A., Omote, H., Nakamoto, R. K., and Al-Shawi, M. K. (2000) Arch. Biochem. Biophys. 376, 34-46) as well as Chinese hamster Pgp (PGP1). Between 23 and 35 degrees C, we obtained linear Arrhenius relationships for the turnover rate of hydrolysis of saturating MgATP in the presence of saturating drug concentrations (kcat), from which we calculated the intrinsic enthalpic, entropic, and free energy terms for the rate-limiting transition states. Linearity of the Arrhenius plots indicated that the same rate-limiting step was being measured over the temperature range employed. Using linear free energy analysis, two distinct transition states were found: one associated with uncoupled basal activity and the other with coupled drug transport activity. We concluded that basal ATPase activity associated with Pgp is not a consequence of transport of an endogenous lipid or other endogenous substrates. Rather, it is an intrinsic mechanistic property of the enzyme. We also found that rapidly transported substrates bound tighter to the transition state and required fewer conformational alterations by the enzyme to achieve the coupling transition state. The overall rate-limiting step of Pgp during transport is a carrier reorientation step. Furthermore, Pgp is optimized to transport drugs out of cells at high rates at the expense of coupling efficiency. The drug inhibition phase was associated with low affinity drug-binding sites. These results are consistent with an expanded version of the alternating catalytic site drug transport model (Senior, A. E., Al-Shawi, M. K., and Urbatsch, I. L. (1995) FEBS Lett. 377, 285-289). A new kinetic model of drug transport is presented.
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Affiliation(s)
- Marwan K Al-Shawi
- Department of Molecular Physiology and Biological Physics, University of Virginia Health System, Charlottesville, Virginia 22908-0736, USA.
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38
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Litman T, Skovsgaard T, Stein WD. Pumping of drugs by P-glycoprotein: a two-step process? J Pharmacol Exp Ther 2003; 307:846-53. [PMID: 14534356 DOI: 10.1124/jpet.103.056960] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The apparent inhibition constant, Kapp, for the blockade of P-glycoprotein (P-gp) by four drugs, verapamil, cyclosporin A, XR9576 (tariquidar), and vinblastine, was measured by studying their ability to inhibit daunorubicin and calcein-AM efflux from four strains of Ehrlich cells with different levels of drug resistance and P-gp content. For daunorubicin as a transport substrate, Kapp was independent of [P-gp] for verapamil but increased strictly linearly with [P-gp] for vinblastine, cyclosporin A, and XR9576. A theoretical analysis of the kinetics of drug pumping and its reversal shows that Kapp for inhibition should increase linearly with the amount of pumps present in the membrane for a reverser that inhibits pumping from the cytoplasmic face. In contrast, if the reverser acts by blocking transport from the outer face, i.e., preemptively, Kapp should be independent of the number of pumps present. The experimental data suggest that verapamil blocks pumping at the extracellular face of the membrane, whereas the other three blockers act on pumping from the cytoplasmic phase. The maximum degree of inhibition was the same for all four blockers; thus, they do not act in parallel but rather, in serial, i.e., a drug that is pumped from the cytoplasmic phase has to pass the preemptive route upon leaving the cell. Our results are consistent with the Sauna-Ambudkar two-step model for pumping by P-gp. We suggest that the vinblastine/cyclosporin A/XR9576-binding site accepts daunorubicin at the cytoplasmic face and transfers it to the verapamil-binding site, from where daunorubicin is emptied at the extracellular surface.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Algorithms
- Animals
- Anti-Bacterial Agents/metabolism
- Antineoplastic Agents, Phytogenic/metabolism
- Blotting, Western
- Calcium Channel Blockers/metabolism
- Carcinoma, Ehrlich Tumor/metabolism
- Cell Line, Tumor
- Cyclosporine/metabolism
- Daunorubicin/metabolism
- Fluoresceins/metabolism
- Humans
- Immunosuppressive Agents/metabolism
- Kinetics
- Models, Biological
- Pharmaceutical Preparations/metabolism
- Quinolines/metabolism
- Verapamil/metabolism
- Vinblastine/metabolism
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Affiliation(s)
- Thomas Litman
- Bioinformatics Centre, University of Copenhagen, Universitetsparken 15, Bldg. 10, DK-2100 Copenhagen, Denmark.
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Ikenaka Y, Yoshiji H, Kuriyama S, Yoshii J, Noguchi R, Tsujinoue H, Yanase K, Namisaki T, Imazu H, Masaki T, Fukui H. Tissue inhibitor of metalloproteinases-1 (TIMP-1) inhibits tumor growth and angiogenesis in the TIMP-1 transgenic mouse model. Int J Cancer 2003; 105:340-6. [PMID: 12704667 DOI: 10.1002/ijc.11094] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) has been recognized as a multifunctional protein. The role of TIMPs in cancer remains the subject of conflicting reports with an antitumor activity or a tumor growth stimulation activity by several mechanisms. The aim of our study is to investigate the effect of ectopic TIMP-1 overexpression on the primary transplanted tumor growth. We employed transgenic mice overexpressing the human TIMP-1 (hTIMP-1) in the liver under control of the albumin promoter/enhancer (TIMP-Tg-mice) and producing high serum levels of TIMP-1. We used the transplantable Ehrlich tumor cells in the current study. The allograft study revealed that the tumor growth in the TIMP-Tg-mice was more significantly inhibited than control (Cont) mice by associated suppression of neovascularization in the tumor. The in vitro studies showed that the recombinant TIMP-1 (rTIMP-1) did not affect the proliferation of the endothelial cells (ECs) and tumor cells, suggesting that the tumor suppressive effect of TIMP-1 was not due to cytotoxicity. TIMP-1 significantly inhibited EC tubular formation in vitro. Furthermore, TIMP-1 treatment did not affect the levels of matrix metalloproteinase (MMP)-2 and MMP-9 mRNA in the Ehrlich tumor cells in vitro, although these expressions in the tumor were markedly suppressed in the TIMP-Tg-mice, compared to the Cont-mice at the end of the experiment. These results suggested that the ectopically overexpressed TIMP-1 inhibited the tumor growth by angiogenesis suppression.
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Affiliation(s)
- Yasuhide Ikenaka
- Third Department of Internal Medicine, Nara Medical University, Nara, Japan
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40
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Robey RW, Honjo Y, van de Laar A, Miyake K, Regis JT, Litman T, Bates SE. A functional assay for detection of the mitoxantrone resistance protein, MXR (ABCG2). BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1512:171-82. [PMID: 11406094 DOI: 10.1016/s0005-2736(01)00308-x] [Citation(s) in RCA: 201] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The fluorescent compounds rhodamine 123, LysoTracker Green DMD-26, mitoxantrone, and BODIPY-prazosin were used with the antagonist fumitremorgin C (FTC) in order to develop functional assays for the half-transporter, MXR/BCRP/ABCP1. A measure of FTC-inhibitable efflux was generated for each compound in a series of MXR-overexpressing drug-selected cell lines and in ten unselected cell lines which were used to determine if the four fluorescent compounds were sensitive enough to detect the low MXR levels found in drug-sensitive cell lines. FTC-inhibitable efflux of mitoxantrone and prazosin was found in four of the ten cell lines, SF295, KM12, NCI-H460, and A549, and low but detectable levels of MXR mRNA were also observed by Northern analysis in these cells. FTC-inhibitable mitoxantrone and prazosin efflux in both selected and unselected cell lines was found to correlate well with MXR levels as determined by Northern blotting, r(2)=0.89 and r(2)=0.70 respectively. In contrast, rhodamine and LysoTracker were not able to reliably detect MXR. Cytotoxicity assays performed on two of the four unselected cell lines confirmed increased sensitivity to mitoxantrone in the presence of FTC. FTC was found to be a specific inhibitor of MXR, with half-maximal inhibition of MXR-associated ATPase activity at 1 microM FTC. Short term selections of the SF295, KM12, NCI-H460 and A549 cell lines in mitoxantrone resulted in a small but measurable increase in MXR by both Northern blot and functional assay. These studies show that flow cytometric measurement of FTC-inhibitable mitoxantrone or prazosin efflux is a sensitive and specific method for measuring the function of the MXR half-transporter in both selected and unselected cell lines.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP Binding Cassette Transporter, Subfamily G, Member 2
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Adenosine Triphosphatases/genetics
- Adenosine Triphosphatases/metabolism
- Boron Compounds
- Breast Neoplasms
- Cell Survival/drug effects
- Colonic Neoplasms
- Drug Resistance, Multiple/genetics
- Drug Resistance, Multiple/physiology
- Female
- Fluorescent Dyes
- Gene Expression Regulation, Neoplastic
- Humans
- Intracellular Membranes/metabolism
- Kinetics
- Microsomes/metabolism
- Mitoxantrone/toxicity
- Neoplasm Proteins
- Polymerase Chain Reaction
- Prazosin/pharmacokinetics
- RNA, Messenger/genetics
- Transcription, Genetic
- Tumor Cells, Cultured
- Verapamil/pharmacology
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Affiliation(s)
- R W Robey
- Developmental Therapeutics Department, Medicine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Building 10, Room 12N226, 9000 Rockville Pike, Bethesda, MD 20892, USA
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41
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Kerr KM, Sauna ZE, Ambudkar SV. Correlation between steady-state ATP hydrolysis and vanadate-induced ADP trapping in Human P-glycoprotein. Evidence for ADP release as the rate-limiting step in the catalytic cycle and its modulation by substrates. J Biol Chem 2001; 276:8657-64. [PMID: 11121420 DOI: 10.1074/jbc.m010044200] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
P-glycoprotein (Pgp) is a transmembrane protein conferring multidrug resistance to cells by extruding a variety of amphipathic cytotoxic agents using energy from ATP hydrolysis. The objective of this study was to understand how substrates affect the catalytic cycle of ATP hydrolysis by Pgp. The ATPase activity of purified and reconstituted recombinant human Pgp was measured using a continuous cycling assay. Pgp hydrolyzes ATP in the absence of drug at a basal rate of 0.5 micromol x min x mg(-1) with a K(m) for ATP of 0.33 mm. This basal rate can be either increased or decreased depending on the Pgp substrate used, without an effect on the K(m) for ATP or 8-azidoATP and K(i) for ADP, suggesting that substrates do not affect nucleotide binding to Pgp. Although inhibitors of Pgp activity, cyclosporin A, its analog PSC833, and rapamycin decrease the rate of ATP hydrolysis with respect to the basal rate, they do not completely inhibit the activity. Therefore, these drugs can be classified as substrates. Vanadate (Vi)-induced trapping of [alpha-(32)P]8-azidoADP was used to probe the effect of substrates on the transition state of the ATP hydrolysis reaction. The K(m) for [alpha-(32)P]8-azidoATP (20 microm) is decreased in the presence of Vi; however, it is not changed by drugs such as verapamil or cyclosporin A. Strikingly, the extent of Vi-induced [alpha-(32)P]8-azidoADP trapping correlates directly with the fold stimulation of ATPase activity at steady state. Furthermore, P(i) exhibits very low affinity for Pgp (K(i) approximately 30 mm for Vi-induced 8-azidoADP trapping). In aggregate, these data demonstrate that the release of Vi trapped [alpha-(32)P]8-azidoADP from Pgp is the rate-limiting step in the steady-state reaction. We suggest that substrates modulate the rate of ATPase activity of Pgp by controlling the rate of dissociation of ADP following ATP hydrolysis and that ADP release is the rate-limiting step in the normal catalytic cycle of Pgp.
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Affiliation(s)
- K M Kerr
- Laboratory of Cell Biology, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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Seelig A, Landwojtowicz E. Structure-activity relationship of P-glycoprotein substrates and modifiers. Eur J Pharm Sci 2000; 12:31-40. [PMID: 11121731 DOI: 10.1016/s0928-0987(00)00177-9] [Citation(s) in RCA: 197] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The air-water partition coefficients, K(aw), highly correlated with the corresponding lipid-water partition coefficients, K(lw), and the critical micelle concentrations, CMC, were measured for 11 compounds for which the kinetic parameters of P-glycoprotein ATPase activation (Michaelis-Menten constant, K(m), and maximal velocity, V(max)) had been determined previously in inside-out vesicles of CR1R12 Chinese hamster ovary cells. In addition, the hydrogen bond donor patterns (type I and type II) relevant for substrate recognition by P-glycoprotein were determined from the energy-minimized three-dimensional structure of these compounds. A linear relation between the air-water partition coefficient, K(aw), and the inverse of the Michaelis-Menten constant, K(m), was observed such that K(m) x K(aw) approximately = 1. The maximal velocity, V(max), was shown to decrease with the number and strength of electron donor (hydrogen bond acceptor) groups in recognition patterns. If two substrates are applied simultaneously to P-glycoprotein the compound with the higher potential to form hydrogen bonds generally acts as an inhibitor. We conclude that partitioning into the lipid membrane is the rate-limiting step for the interaction of a substrate with P-glycoprotein and that dissociation of the P-glycoprotein-substrate complex is determined by the number and strength of the hydrogen bonds formed between the substrate and the transporter.
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Affiliation(s)
- A Seelig
- Department of Biophysical Chemistry, Biocenter, University of Basel, Klingelbergstrasse 70, Basel, Switzerland.
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Hooijberg JH, Pinedo HM, Vrasdonk C, Priebe W, Lankelma J, Broxterman HJ. The effect of glutathione on the ATPase activity of MRP1 in its natural membranes. FEBS Lett 2000; 469:47-51. [PMID: 10708754 DOI: 10.1016/s0014-5793(00)01238-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The transport mechanism by which the multidrug resistance protein 1 (MRP1) effluxes cytotoxic agents out of cells is still not completely understood. However, the cellular antioxidant glutathione (GSH) has been shown to have an important role in MRP1-mediated drug transport. In this study we show that GSH stimulates the ATPase activity of MRP1 in a natural plasma membrane environment. This stimulation was dose-dependent up to 5 mM. The MRP1 substrates vincristine and daunorubicin do not induce MRP1 ATPase activity. In addition, the effect of GSH on the MRP1 ATPase activity is not increased by daunorubicin or by vincristine. In contrast, a GSH conjugate of daunorubicin (WP811) does induce the ATPase activity of MRP1. In the presence of GSH the effect of WP811 was not significantly increased. Finally, (iso)flavonoid-induced MRP1 ATPase activity is not synergistically increased by the presence of GSH. In conclusion, we show that GSH has no apparent influence on the ATPase reaction induced by several MRP1 substrates and/or modulators. The subclasses of molecules had different effects on the MRP1 ATPase activity, which supports the existence of different drug binding sites.
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Affiliation(s)
- J H Hooijberg
- Department of Medical Oncology, Academisch Ziekenhuis Vrije Universiteit, Room BR 232, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
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