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Moesgaard L, Pedersen ML, Uhd Nielsen C, Kongsted J. Structure-based discovery of novel P-glycoprotein inhibitors targeting the nucleotide binding domains. Sci Rep 2023; 13:21217. [PMID: 38040777 PMCID: PMC10692163 DOI: 10.1038/s41598-023-48281-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/24/2023] [Indexed: 12/03/2023] Open
Abstract
P-glycoprotein (P-gp), a membrane transport protein overexpressed in certain drug-resistant cancer cells, has been the target of numerous drug discovery projects aimed at overcoming drug resistance in cancer. Most characterized P-gp inhibitors bind at the large hydrophobic drug binding domain (DBD), but none have yet attained regulatory approval. In this study, we explored the potential of designing inhibitors that target the nucleotide binding domains (NBDs), by computationally screening a large library of 2.6 billion synthesizable molecules, using a combination of machine learning-guided molecular docking and molecular dynamics (MD). 14 of the computationally best-scoring molecules were subsequently tested for their ability to inhibit P-gp mediated calcein-AM efflux. In total, five diverse compounds exhibited inhibitory effects in the calcein-AM assay without displaying toxicity. The activity of these compounds was confirmed by their ability to decrease the verapamil-stimulated ATPase activity of P-gp in a subsequent assay. The discovery of these five novel P-gp inhibitors demonstrates the potential of in-silico screening in drug discovery and provides a new stepping point towards future potent P-gp inhibitors.
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Affiliation(s)
- Laust Moesgaard
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, 5230, Denmark.
| | - Maria L Pedersen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, 5230, Denmark
| | - Carsten Uhd Nielsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, 5230, Denmark
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, 5230, Denmark
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2
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Burguera S, Frontera A, Bauzá A. Biological noncovalent N/O⋯V interactions: insights from theory and protein data bank analyses. Phys Chem Chem Phys 2023; 25:30040-30048. [PMID: 37905702 DOI: 10.1039/d3cp04571d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Computations at the PBE0-D3/def2-TZVP level of theory in conjunction with a Protein Data Bank (PDB) survey have provided first time evidence of favorable noncovalent interactions between ADP metavanadate (VO4) and ADP orthovanadate (VO5) and electron rich atoms. These involve a σ-hole present in the V atom and the lone pairs belonging to (i) protein residues (e.g., serine (SER), glutamate (GLU) or histidine (HIS)), (ii) backbone carbonyl groups and (iii) water molecules. A computational study has been carried out to rationalize the physical nature and directionality of the interaction in addition to its plausible biological role. The results reported herein are expected to have an impact in the fields of medicinal chemistry, bioinorganic chemistry and chemical biology.
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Affiliation(s)
- Sergi Burguera
- Department of Chemistry, Universitat de les Illes Balears, Ctra. de Valldemossa km. 7.5, 07122, Palma de Mallorca, Islas Baleares, Spain.
| | - Antonio Frontera
- Department of Chemistry, Universitat de les Illes Balears, Ctra. de Valldemossa km. 7.5, 07122, Palma de Mallorca, Islas Baleares, Spain.
| | - Antonio Bauzá
- Department of Chemistry, Universitat de les Illes Balears, Ctra. de Valldemossa km. 7.5, 07122, Palma de Mallorca, Islas Baleares, Spain.
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3
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Mensah GAK, Schaefer KG, Bartlett MG, Roberts AG, King GM. Drug-Induced Conformational Dynamics of P-Glycoprotein Underlies the Transport of Camptothecin Analogs. Int J Mol Sci 2023; 24:16058. [PMID: 38003248 PMCID: PMC10671697 DOI: 10.3390/ijms242216058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 10/24/2023] [Accepted: 10/28/2023] [Indexed: 11/26/2023] Open
Abstract
P-glycoprotein (Pgp) plays a pivotal role in drug bioavailability and multi-drug resistance development. Understanding the protein's activity and designing effective drugs require insight into the mechanisms underlying Pgp-mediated transport of xenobiotics. In this study, we investigated the drug-induced conformational changes in Pgp and adopted a conformationally-gated model to elucidate the Pgp-mediated transport of camptothecin analogs (CPTs). While Pgp displays a wide range of conformations, we simplified it into three model states: 'open-inward', 'open-outward', and 'intermediate'. Utilizing acrylamide quenching of Pgp fluorescence as a tool to examine the protein's tertiary structure, we observed that topotecan (TPT), SN-38, and irinotecan (IRT) induced distinct conformational shifts in the protein. TPT caused a substantial shift akin to AMPPNP, suggesting ATP-independent 'open-outward' conformation. IRT and SN-38 had relatively moderate effects on the conformation of Pgp. Experimental atomic force microscopy (AFM) imaging supports these findings. Further, the rate of ATPase hydrolysis was correlated with ligand-induced Pgp conformational changes. We hypothesize that the separation between the nucleotide-binding domains (NBDs) creates a conformational barrier for substrate transport. Substrates that reduce the conformational barrier, like TPT, are better transported. The affinity for ATP extracted from Pgp-mediated ATP hydrolysis kinetics curves for TPT was about 2-fold and 3-fold higher than SN-38 and IRT, respectively. On the contrary, the dissociation constants (KD) determined by fluorescence quenching for these drugs were not significantly different. Saturation transfer double difference (STDD) NMR of TPT and IRT with Pgp revealed that similar functional groups of the CPTs are accountable for Pgp-CPTs interactions. Efforts aimed at modifying these functional groups, guided by available structure-activity relationship data for CPTs and DNA-Topoisomerase-I complexes, could pave the way for the development of more potent next-generation CPTs.
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Affiliation(s)
- Gershon A. K. Mensah
- Department of Pharmaceutical and Biomedical Science, University of Georgia, Athens, GA 30602, USA; (G.A.K.M.)
| | - Katherine G. Schaefer
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA;
| | - Michael G. Bartlett
- Department of Pharmaceutical and Biomedical Science, University of Georgia, Athens, GA 30602, USA; (G.A.K.M.)
| | - Arthur G. Roberts
- Department of Pharmaceutical and Biomedical Science, University of Georgia, Athens, GA 30602, USA; (G.A.K.M.)
| | - Gavin M. King
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA;
- Joint with Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
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4
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Murakami M, Sajid A, Lusvarghi S, Durell SR, Abel B, Vahedi S, Golin J, Ambudkar SV. Second-site suppressor mutations reveal connection between the drug-binding pocket and nucleotide-binding domain 1 of human P-glycoprotein (ABCB1). Drug Resist Updat 2023; 71:101009. [PMID: 37797431 PMCID: PMC10842643 DOI: 10.1016/j.drup.2023.101009] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 10/07/2023]
Abstract
Human P-glycoprotein (P-gp) or ABCB1 is overexpressed in many cancers and has been implicated in altering the bioavailability of chemotherapeutic drugs due to their efflux, resulting in the development of chemoresistance. To elucidate the mechanistic aspects and structure-function relationships of P-gp, we previously utilized a tyrosine (Y)-enriched P-gp mutant (15Y) and demonstrated that at least 15 conserved residues in the drug-binding pocket of P-gp are responsible for optimal substrate interaction and transport. To further understand the role of these 15 residues, two new mutants were generated, namely 6Y with the substitution of six residues (F72, F303, I306, F314, F336 and L339) with Y in transmembrane domain (TMD) 1 and 9Y with nine substitutions (F732, F759, F770, F938, F942, M949, L975, F983 and F994) in TMD2. Although both the mutants were expressed at normal levels at the cell surface, the 6Y mutant failed to transport all the tested substrates except Bodipy-verapamil, whereas the 9Y mutant effluxed all tested substrates in a manner very similar to that of the wild-type protein. Further mutational analysis revealed that two second-site mutations, one in intracellular helix (ICH) 4 (F916Y) and one in the Q loop of nucleotide-binding domain (NBD) 1 (F480Y) restored the transport function of 6Y. Additional biochemical data and comparative molecular dynamics simulations of the 6Y and 6Y+F916Y mutant indicate that the Q-loop of NBD1 of P-gp communicates with the substrate-binding sites in the transmembrane region through ICH4. This is the first evidence for the existence of second-site suppressors in human P-gp that allow recovery of the loss of transport function caused by primary mutations. Further study of such mutations could facilitate mapping of the communication pathway between the substrate-binding pocket and the NBDs of P-gp and possibly other ABC drug transporters.
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Affiliation(s)
- Megumi Murakami
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Andaleeb Sajid
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Stewart R Durell
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Biebele Abel
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Shahrooz Vahedi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - John Golin
- Department of Biology, Catholic University of America, Washington, DC 20064, USA
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
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5
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Rahman H, Ware MJ, Sajid A, Lusvarghi S, Durell SR, Ambudkar SV. Residues from Homologous Transmembrane Helices 4 and 10 Are Critical for P-Glycoprotein (ABCB1)-Mediated Drug Transport. Cancers (Basel) 2023; 15:3459. [PMID: 37444569 DOI: 10.3390/cancers15133459] [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: 05/11/2023] [Revised: 06/27/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
P-glycoprotein (P-gp, ABCB1) transports structurally dissimilar hydrophobic and amphipathic compounds, including anticancer drugs, thus contributing to multidrug-resistant cancer. Cryo-EM structures of human P-gp revealed that TMHs 4 and 10 contribute to the formation of the drug-binding cavity and undergo conformational changes during drug transport. To assess the role of the conformational changes in TMH4 and TMH10 during drug transport, we generated two mutants (TMH4-7A and TMH10-7A), each containing seven alanine substitutions. Analysis of the drug efflux function of these mutants using 15 fluorescent substrates revealed that most of the substrates were transported, indicating that even seven mutations in an individual helix have no significant effect on transport function. We then designed the TMH4,10-14A mutant combining seven mutations in both TMHs 4 and 10. Interestingly, when the TMH4,10-14A mutant was tested with 15 substrates, there was no efflux observed for fourteen. The basal ATPase activity of the TMH4,10-14A mutant, similar to that of the WT protein, was inhibited by zosuquidar but was not stimulated by verapamil or rhodamine 6G. Molecular dynamics simulations indicated that the mutations cause TMHs 4 and 10 to pack tighter to their proximal helices, reducing their independent mobility. In aggregate, our findings demonstrate the critical role of the residues of homologous TMHs 4 and 10 for substrate transport, consistent with conformational changes observed in the structure of P-gp.
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Affiliation(s)
- Hadiar Rahman
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
| | - Mark J Ware
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
| | - Andaleeb Sajid
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
| | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
| | - Stewart R Durell
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
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6
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Jones PM, George AM. The Switch and Reciprocating Models for the Function of ABC Multidrug Exporters: Perspectives on Recent Research. Int J Mol Sci 2023; 24:ijms24032624. [PMID: 36768947 PMCID: PMC9917156 DOI: 10.3390/ijms24032624] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/23/2023] [Accepted: 01/26/2023] [Indexed: 02/03/2023] Open
Abstract
ATP-binding cassette (ABC) transporters comprise a large superfamily of primary active transporters, which are integral membrane proteins that couple energy to the uphill vectorial transport of substrates across cellular membranes, with concomitant hydrolysis of ATP. ABC transporters are found in all living organisms, coordinating mostly import in prokaryotes and export in eukaryotes. Unlike the highly conserved nucleotide binding domains (NBDs), sequence conservation in the transmembrane domains (TMDs) is low, with their divergent nature likely reflecting a need to accommodate a wide range of substrate types in terms of mass and polarity. An explosion in high resolution structural analysis over the past decade and a half has produced a wealth of structural information for ABCs. Based on the structures, a general mechanism for ABC transporters has been proposed, known as the Switch or Alternating Access Model, which holds that the NBDs are widely separated, with the TMDs and NBDs together forming an intracellular-facing inverted "V" shape. Binding of two ATPs and the substrate to the inward-facing conformation induces a transition to an outward conformation. Despite this apparent progress, certainty around the transport mechanism for any given ABC remains elusive. How substrate binding and transport is coupled to ATP binding and hydrolysis is not known, and there is a large body of biochemical and biophysical data that is at odds with the widely separated NBDs being a functional physiological state. An alternative Constant Contact model has been proposed in which the two NBSs operate 180 degrees out of phase with respect to ATP hydrolysis, with the NBDs remaining in close proximity throughout the transport cycle and operating in an asymmetric allosteric manner. The two models are discussed in the light of recent nuclear magnetic resonance and hydrogen-deuterium exchange mass spectrometry analyses of three ABC exporters.
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7
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Ng JPL, Tiwari MK, Nasim AA, Zhang RL, Qu Y, Sharma R, Law BYK, Yadav DK, Chaudhary S, Coghi P, Wong VKW. Biological Evaluation in Resistant Cancer Cells and Study of Mechanism of Action of Arylvinyl-1,2,4-Trioxanes. Pharmaceuticals (Basel) 2022; 15:ph15030360. [PMID: 35337157 PMCID: PMC8955836 DOI: 10.3390/ph15030360] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/06/2022] [Accepted: 03/09/2022] [Indexed: 12/04/2022] Open
Abstract
1,2,4-trioxane is a pharmacophore, which possesses a wide spectrum of biological activities, including anticancer effects. In this study, the cytotoxic effect and anticancer mechanism of action of a set of 10 selected peroxides were investigated on five phenotypically different cancer cell lines (A549, A2780, HCT8, MCF7, and SGC7901) and their corresponding drug-resistant cancer cell lines. Among all peroxides, only 7 and 8 showed a better P-glycoprotein (P-gp) inhibitory effect at a concentration of 100 nM. These in vitro results were further validated by in silico docking and molecular dynamic (MD) studies, where compounds 7 and 8 exhibited docking scores of −7.089 and −8.196 kcal/mol, respectively, and remained generally stable in 100 ns during MD simulation. Further experiments revealed that peroxides 7 and 8 showed no significant effect on ROS accumulations and caspase-3 activity in A549 cells. Peroxides 7 and 8 were also found to decrease cell membrane potential. In addition, peroxides 7 and 8 were demonstrated to oxidize a flavin cofactor, possibly elucidating its mechanism of action. In conclusion, apoptosis induced by 1,2,4-trioxane was shown to undergo via a ROS- and caspase-3-independent pathway with hyperpolarization of cell membrane potential.
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Affiliation(s)
- Jerome P. L. Ng
- Neher’s Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau 999078, China; (J.P.L.N.); (A.A.N.); (R.L.Z.); (Y.Q.); (B.Y.K.L.)
| | - Mohit K. Tiwari
- Laboratory of Organic and Medicinal Chemistry, Department of Chemistry, Malaviya National Institute of Technology, Jawaharlal Nehru Marg, Jaipur 302017, India; (M.K.T.); (R.S.)
| | - Ali Adnan Nasim
- Neher’s Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau 999078, China; (J.P.L.N.); (A.A.N.); (R.L.Z.); (Y.Q.); (B.Y.K.L.)
| | - Rui Long Zhang
- Neher’s Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau 999078, China; (J.P.L.N.); (A.A.N.); (R.L.Z.); (Y.Q.); (B.Y.K.L.)
| | - Yuanqing Qu
- Neher’s Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau 999078, China; (J.P.L.N.); (A.A.N.); (R.L.Z.); (Y.Q.); (B.Y.K.L.)
| | - Richa Sharma
- Laboratory of Organic and Medicinal Chemistry, Department of Chemistry, Malaviya National Institute of Technology, Jawaharlal Nehru Marg, Jaipur 302017, India; (M.K.T.); (R.S.)
| | - Betty Yuen Kwan Law
- Neher’s Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau 999078, China; (J.P.L.N.); (A.A.N.); (R.L.Z.); (Y.Q.); (B.Y.K.L.)
| | - Dharmendra K. Yadav
- College of Pharmacy, Gachon University of Medicine and Science, Incheon City 21924, Korea
- Correspondence: (D.K.Y.); (S.C.); (P.C.); (V.K.W.W.)
| | - Sandeep Chaudhary
- Laboratory of Organic and Medicinal Chemistry, Department of Chemistry, Malaviya National Institute of Technology, Jawaharlal Nehru Marg, Jaipur 302017, India; (M.K.T.); (R.S.)
- Laboratory of Organic and Medicinal Chemistry (OMC Lab), National Institute of Pharmaceutical Education and Research (NIPER-R) Raebareli, Lucknow 226002, India
- Correspondence: (D.K.Y.); (S.C.); (P.C.); (V.K.W.W.)
| | - Paolo Coghi
- School of Pharmacy, Macau University of Science and Technology, Macau 999078, China
- Correspondence: (D.K.Y.); (S.C.); (P.C.); (V.K.W.W.)
| | - Vincent Kam Wai Wong
- Neher’s Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau 999078, China; (J.P.L.N.); (A.A.N.); (R.L.Z.); (Y.Q.); (B.Y.K.L.)
- Correspondence: (D.K.Y.); (S.C.); (P.C.); (V.K.W.W.)
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8
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Abel B, Murakami M, Tosh DK, Yu J, Lusvarghi S, Campbell RG, Gao ZG, Jacobson KA, Ambudkar SV. Interaction of A 3 adenosine receptor ligands with the human multidrug transporter ABCG2. Eur J Med Chem 2022; 231:114103. [PMID: 35152062 PMCID: PMC8893036 DOI: 10.1016/j.ejmech.2022.114103] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/03/2022] [Accepted: 01/06/2022] [Indexed: 12/19/2022]
Abstract
Various adenosine receptor nucleoside-like ligands were found to modulate ATP hydrolysis by the multidrug transporter ABCG2. Both ribose-containing and rigidified (N)-methanocarba nucleosides (C2-, N6- and 5'-modified), as well as adenines (C2-, N6-, and deaza modified), were included. 57 compounds out of 63 tested either stimulated (50) or inhibited (7) basal ATPase activity. Structure-activity analysis showed a separation of adenosine receptor and ABCG2 activities. The 7-deaza modification had favorable effects in both (N)-methanocarba nucleosides and adenines. Adenine 37c (MRS7608) and (N)-methanocarba 7-deaza-5'-ethyl ester 60 (MRS7343) were found to be potent stimulators of ABCG2 ATPase activity with EC50 values of 13.2 ± 1.7 and 13.2 ± 2.2 nM, respectively. Both had affinity in the micromolar range for A3 adenosine receptor and lacked the 5'-amide agonist-enabling group (37c was reported as a weak A3 antagonist, Ki 6.82 μM). Compound 60 significantly inhibited ABCG2 substrate transport (IC50 0.44 μM). Docking simulations predicted the interaction of 60 with 21 residues in the drug-binding pocket of ABCG2.
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Affiliation(s)
- Biebele Abel
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (BA, MM, SL, SVA), USA
| | - Megumi Murakami
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (BA, MM, SL, SVA), USA
| | - Dilip K Tosh
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (DKT, JY, RGC, ZGG, KAJ), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jinha Yu
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (DKT, JY, RGC, ZGG, KAJ), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (BA, MM, SL, SVA), USA
| | - Ryan G Campbell
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (DKT, JY, RGC, ZGG, KAJ), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (DKT, JY, RGC, ZGG, KAJ), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (DKT, JY, RGC, ZGG, KAJ), National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (BA, MM, SL, SVA), USA.
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9
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Dehghani-Ghahnaviyeh S, Kapoor K, Tajkhorshid E. Conformational changes in the nucleotide-binding domains of P-glycoprotein induced by ATP hydrolysis. FEBS Lett 2020; 595:735-749. [PMID: 33159693 DOI: 10.1002/1873-3468.13992] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/19/2020] [Accepted: 10/30/2020] [Indexed: 12/16/2022]
Abstract
P-glycoprotein (Pgp) is a member of the ABC transporter superfamily with high physiological importance. Pgp nucleotide-binding domains (NBDs) drive the transport cycle through ATP binding and hydrolysis. We use molecular dynamics simulations to investigate the ATP hydrolysis-induced conformational changes in NBDs. Five systems, including all possible ATP/ADP combinations in the NBDs and the APO system, are simulated. ATP/ADP exchange induces conformational changes mostly within the conserved signature motif of the NBDs, resulting in relative orientational changes in the NBDs. Nucleotide removal leads to additional orientational changes in the NBDs, allowing their dissociation. Furthermore, we capture putative hydrolysis-competent configurations in which the conserved glutamate in the Walker-B motif acts as a catalytic base capturing a water molecule likely initiating ATP hydrolysis.
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Affiliation(s)
- Sepehr Dehghani-Ghahnaviyeh
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Center for Biophysics and Quantitative Biology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, IL, USA
| | - Karan Kapoor
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Center for Biophysics and Quantitative Biology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, IL, USA
| | - Emad Tajkhorshid
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Center for Biophysics and Quantitative Biology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, IL, USA
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10
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Reversing the direction of drug transport mediated by the human multidrug transporter P-glycoprotein. Proc Natl Acad Sci U S A 2020; 117:29609-29617. [PMID: 33168729 PMCID: PMC7703596 DOI: 10.1073/pnas.2016270117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The multidrug transporter P-glycoprotein protects tissues from xenobiotics and other toxic compounds by pumping them out of cells. This transporter has been implicated in altering the bioavailability of chemotherapeutic drugs and in the development of multidrug resistance in tumor cells. Despite decades of research, the modulation of P-glycoprotein to overcome drug resistance in the clinic has not been successful. Here, by substituting a group of 14 conserved residues in homologous transmembrane helices 6 and 12 with alanine, we generated a mutant that exhibits a change in the direction of transport from export to import for certain drug substrates including the taxol derivative flutax-1. The ability to convert P-glycoprotein into a drug importer provides a strategy to combat cancer drug resistance. P-glycoprotein (P-gp), also known as ABCB1, is a cell membrane transporter that mediates the efflux of chemically dissimilar amphipathic drugs and confers resistance to chemotherapy in most cancers. Homologous transmembrane helices (TMHs) 6 and 12 of human P-gp connect the transmembrane domains with its nucleotide-binding domains, and several residues in these TMHs contribute to the drug-binding pocket. To investigate the role of these helices in the transport function of P-gp, we substituted a group of 14 conserved residues (seven in both TMHs 6 and 12) with alanine and generated a mutant termed 14A. Although the 14A mutant lost the ability to pump most of the substrates tested out of cancer cells, surprisingly, it acquired a new function. It was able to import four substrates, including rhodamine 123 (Rh123) and the taxol derivative flutax-1. Similar to the efflux function of wild-type P-gp, we found that uptake by the 14A mutant is ATP hydrolysis-, substrate concentration-, and time-dependent. Consistent with the uptake function, the mutant P-gp also hypersensitizes HeLa cells to Rh123 by 2- to 2.5-fold. Further mutagenesis identified residues from both TMHs 6 and 12 that synergistically form a switch in the central region of the two helices that governs whether a given substrate is pumped out of or into the cell. Transforming P-gp or an ABC drug exporter from an efflux transporter into a drug uptake pump would constitute a paradigm shift in efforts to overcome cancer drug resistance.
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11
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Goda K, Dönmez-Cakil Y, Tarapcsák S, Szalóki G, Szöllősi D, Parveen Z, Türk D, Szakács G, Chiba P, Stockner T. Human ABCB1 with an ABCB11-like degenerate nucleotide binding site maintains transport activity by avoiding nucleotide occlusion. PLoS Genet 2020; 16:e1009016. [PMID: 33031417 PMCID: PMC7544095 DOI: 10.1371/journal.pgen.1009016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 07/29/2020] [Indexed: 11/28/2022] Open
Abstract
Several ABC exporters carry a degenerate nucleotide binding site (NBS) that is unable to hydrolyze ATP at a rate sufficient for sustaining transport activity. A hallmark of a degenerate NBS is the lack of the catalytic glutamate in the Walker B motif in the nucleotide binding domain (NBD). The multidrug resistance transporter ABCB1 (P-glycoprotein) has two canonical NBSs, and mutation of the catalytic glutamate E556 in NBS1 renders ABCB1 transport-incompetent. In contrast, the closely related bile salt export pump ABCB11 (BSEP), which shares 49% sequence identity with ABCB1, naturally contains a methionine in place of the catalytic glutamate. The NBD-NBD interfaces of ABCB1 and ABCB11 differ only in four residues, all within NBS1. Mutation of the catalytic glutamate in ABCB1 results in the occlusion of ATP in NBS1, leading to the arrest of the transport cycle. Here we show that despite the catalytic glutamate mutation (E556M), ABCB1 regains its ATP-dependent transport activity, when three additional diverging residues are also replaced. Molecular dynamics simulations revealed that the rescue of ATPase activity is due to the modified geometry of NBS1, resulting in a weaker interaction with ATP, which allows the quadruple mutant to evade the conformationally locked pre-hydrolytic state to proceed to ATP-driven transport. In summary, we show that ABCB1 can be transformed into an active transporter with only one functional catalytic site by preventing the formation of the ATP-locked pre-hydrolytic state in the non-canonical site. ABC transporters are one of the largest membrane protein superfamilies, present in all organisms from archaea to humans. They transport a wide range of molecules including amino acids, sugars, vitamins, nucleotides, peptides, lipids, metabolites, antibiotics, and xenobiotics. ABC transporters energize substrate transport by hydrolyzing ATP in two symmetrically arranged nucleotide binding sites (NBSs). The human multidrug resistance transporter ABCB1 has two active NBSs, and it is generally believed that integrity and cooperation of both sites are needed for transport. Several human ABC transporters, such as the bile salt transporter ABCB11, have one degenerate NBS, which has significantly reduced ATPase activity. Interestingly, unilateral mutations affecting one of the two NBSs completely abolish the function of symmetrical ABC transporters. Here we engineered an ABCB1 variant with a degenerate, ABCB11-like NBS1, which can nevertheless transport substrates. Our results indicate that ABCB1 can mediate active transport with a single active site, questioning the validity of models assuming strictly alternating catalysis.
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Affiliation(s)
- Katalin Goda
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér, Debrecen, Hungary
| | - Yaprak Dönmez-Cakil
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse, Vienna, Austria
- Department of Histology and Embryology, Faculty of Medicine, Maltepe University, Maltepe, Istanbul, Turkey
| | - Szabolcs Tarapcsák
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér, Debrecen, Hungary
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, Egyetem tér, Debrecen, Hungary
| | - Gábor Szalóki
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér, Debrecen, Hungary
| | - Dániel Szöllősi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse, Vienna, Austria
| | - Zahida Parveen
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Waehringerstrasse, Vienna, Austria
- Department of Biochemistry, Abdul Wali Khan University Mardan, Khyber Pakhtunkhwa, Pakistan
| | - Dóra Türk
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok körútja, Budapest, Hungary
| | - Gergely Szakács
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok körútja, Budapest, Hungary
- Institute of Cancer Research, Medical University of Vienna, Borschkegasse, Vienna, Austria
| | - Peter Chiba
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Waehringerstrasse, Vienna, Austria
- * E-mail: (PC); (TS)
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse, Vienna, Austria
- * E-mail: (PC); (TS)
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12
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Wu CP, Hung CY, Lusvarghi S, Huang YH, Tseng PJ, Hung TH, Yu JS, Ambudkar SV. Overexpression of ABCB1 and ABCG2 contributes to reduced efficacy of the PI3K/mTOR inhibitor samotolisib (LY3023414) in cancer cell lines. Biochem Pharmacol 2020; 180:114137. [PMID: 32634436 DOI: 10.1016/j.bcp.2020.114137] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/26/2020] [Accepted: 07/02/2020] [Indexed: 12/15/2022]
Abstract
LY3023414 (samotolisib) is a promising new dual inhibitor of phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR). Currently, multiple clinical trials are underway to evaluate the efficacy of LY3023414 in patients with various types of cancer. However, the potential mechanisms underlying acquired resistance to LY3023414 in human cancer cells still remain elusive. In this study, we investigated whether the overexpression of ATP-binding cassette (ABC) drug transporters such as ABCB1 and ABCG2, one of the most common mechanisms for developing multidrug resistance, may potentially reduce the efficacy of LY3023414 in human cancer cells. We demonstrated that the intracellular accumulation of LY3023414 in cancer cells was significantly reduced by the drug efflux function of ABCB1 and ABCG2. Consequently, the cytotoxicity and efficacy of LY3023414 for inhibiting the activation of the PI3K pathway and induction of G0/G1 cell-cycle arrest were substantially reduced in cancer cells overexpressing ABCB1 or ABCG2, which could be restored using tariquidar or Ko143, respectively. Furthermore, stimulatory effect of LY3023414 on the ATPase activity of ABCB1 and ABCG2, as well as in silico molecular docking analysis of LY3023414 binding to the substrate-binding pockets of these transporters provided additional insight into the manner in which LY3023414 interacts with both transporters. In conclusion, we report that LY3023414 is a substrate for ABCB1 and ABCG2 transporters implicating their role in the development of resistance to LY3023414, which can have substantial clinical implications and should be further investigated.
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Affiliation(s)
- Chung-Pu Wu
- Graduate Institute of Biomedical Sciences, Taiwan; Department of Physiology and Pharmacology, Taiwan; Molecular Medicine Research Center, Taiwan; Department of Obstetrics and Gynecology, Taipei Chang Gung Memorial Hospital, Taipei, Taiwan.
| | | | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States
| | | | | | - Tai-Ho Hung
- Department of Chinese Medicine, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Obstetrics and Gynecology, Taipei Chang Gung Memorial Hospital, Taipei, Taiwan
| | - Jau-Song Yu
- Graduate Institute of Biomedical Sciences, Taiwan; Molecular Medicine Research Center, Taiwan; Department of Biochemistry and Molecular Biology, Taiwan; Liver Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States
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13
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The Selective Class IIa Histone Deacetylase Inhibitor TMP195 Resensitizes ABCB1- and ABCG2-Overexpressing Multidrug-Resistant Cancer Cells to Cytotoxic Anticancer Drugs. Int J Mol Sci 2019; 21:ijms21010238. [PMID: 31905792 PMCID: PMC6981391 DOI: 10.3390/ijms21010238] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/17/2019] [Accepted: 12/26/2019] [Indexed: 12/16/2022] Open
Abstract
Multidrug resistance caused by the overexpression of the ATP-binding cassette (ABC) proteins in cancer cells remains one of the most difficult challenges faced by drug developers and clinical scientists. The emergence of multidrug-resistant cancers has driven efforts from researchers to develop innovative strategies to improve therapeutic outcomes. Based on the drug repurposing approach, we discovered an additional action of TMP195, a potent and selective inhibitor of class IIa histone deacetylase. We reveal that in vitro TMP195 treatment significantly enhances drug-induced apoptosis and sensitizes multidrug-resistant cancer cells overexpressing ABCB1 or ABCG2 to anticancer drugs. We demonstrate that TMP195 inhibits the drug transport function, but not the protein expression of ABCB1 and ABCG2. The interaction between TMP195 with these transporters was supported by the TMP195-stimulated ATPase activity of ABCB1 and ABCG2, and by in silico docking analysis of TMP195 binding to the substrate-binding pocket of these transporters. Furthermore, we did not find clear evidence of TMP195 resistance conferred by ABCB1 or ABCG2, suggesting that these transporters are unlikely to play a significant role in the development of resistance to TMP195 in cancer patients.
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14
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Sajid A, Raju N, Lusvarghi S, Vahedi S, Swenson RE, Ambudkar SV. Synthesis and Characterization of Bodipy-FL-Cyclosporine A as a Substrate for Multidrug Resistance-Linked P-Glycoprotein (ABCB1). Drug Metab Dispos 2019; 47:1013-1023. [PMID: 31371421 DOI: 10.1124/dmd.119.087734] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/24/2019] [Indexed: 01/15/2023] Open
Abstract
Fluorescent conjugates of drugs can be used to study cellular functions and pharmacology. These compounds interact with proteins as substrates or inhibitors, helping in the development of unique fluorescence-based methods to study in vivo localization and molecular mechanisms. P-glycoprotein (P-gp, ABCB1) is an ATP-binding cassette (ABC) transporter that effluxes most anticancer drugs from cells, contributing to the development of drug resistance. To study the transport function of P-gp, we synthesized a Bodipy-labeled fluorescent conjugate of cyclosporine A (BD-CsA). After synthesis and characterization of its chemical purity, BD-CsA was compared with the commonly used 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD)-CsA probe. In flow cytometry assays, the fluorescence intensity of BD-CsA was almost 10 times greater than that of NBD-CsA, enabling us to use significantly lower concentrations of BD-CsA to achieve the same fluorescence levels. We found that BD-CsA is recognized as a transport substrate by both human and mouse P-gp. The rate of efflux of BD-CsA by human P-gp is comparable to that of NBD-CsA. The transport of BD-CsA was inhibited by tariquidar, with similar IC50 values to those for NBD-CsA. BD-CsA and NBD-CsA both partially inhibited the ATPase activity of P-gp with similar IC50 values. In silico docking of BD-CsA and NBD-CsA to the human P-gp structure indicates that they both bind in the drug-binding pocket with similar docking scores and possibly interact with similar residues. Thus, we demonstrate that BD-CsA is a sensitive fluorescent substrate of P-gp that can be used to efficiently study the transporter's localization and function in vitro and in vivo. SIGNIFICANCE STATEMENT: The goal of this study was to develop an effective probe to study drug transport by P-glycoprotein (P-gp). Fluorophore-conjugated substrates are useful to study the P-gp transport mechanism, structural characteristics, and development of its inhibitors. Cyclosporine A (CsA), a cyclic peptide comprising 11 amino acids, is a known substrate of P-gp. P-gp affects CsA pharmacokinetics and interactions with other coadministered drugs, especially during transplant surgeries and treatment of autoimmune disorders, when CsA is given as an immunosuppressive agent. We synthesized and characterized Bodipy-FL-CsA as an avid fluorescent substrate that can be used to study the function of P-gp both in vitro and in vivo. We demonstrate that Bodipy-FL-conjugation does not affect the properties of CsA as a P-gp substrate.
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Affiliation(s)
- Andaleeb Sajid
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (A.S., S.L., S.V., S.V.A.), and Imaging Probe Development Center, National Heart, Lung and Blood Institute (N.R., R.E.S.), National Institutes of Health, Bethesda, Maryland
| | - Natarajan Raju
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (A.S., S.L., S.V., S.V.A.), and Imaging Probe Development Center, National Heart, Lung and Blood Institute (N.R., R.E.S.), National Institutes of Health, Bethesda, Maryland
| | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (A.S., S.L., S.V., S.V.A.), and Imaging Probe Development Center, National Heart, Lung and Blood Institute (N.R., R.E.S.), National Institutes of Health, Bethesda, Maryland
| | - Shahrooz Vahedi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (A.S., S.L., S.V., S.V.A.), and Imaging Probe Development Center, National Heart, Lung and Blood Institute (N.R., R.E.S.), National Institutes of Health, Bethesda, Maryland
| | - Rolf E Swenson
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (A.S., S.L., S.V., S.V.A.), and Imaging Probe Development Center, National Heart, Lung and Blood Institute (N.R., R.E.S.), National Institutes of Health, Bethesda, Maryland
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (A.S., S.L., S.V., S.V.A.), and Imaging Probe Development Center, National Heart, Lung and Blood Institute (N.R., R.E.S.), National Institutes of Health, Bethesda, Maryland
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15
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Wu CP, Lusvarghi S, Wang JC, Hsiao SH, Huang YH, Hung TH, Ambudkar SV. Avapritinib: A Selective Inhibitor of KIT and PDGFRα that Reverses ABCB1 and ABCG2-Mediated Multidrug Resistance in Cancer Cell Lines. Mol Pharm 2019; 16:3040-3052. [PMID: 31117741 DOI: 10.1021/acs.molpharmaceut.9b00274] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The frequent occurrence of multidrug resistance (MDR) conferred by the overexpression of ATP-binding cassette (ABC) transporters ABCB1 and ABCG2 in cancer cells remains a therapeutic obstacle for scientists and clinicians. Consequently, developing or identifying modulators of ABCB1 and ABCG2 that are suitable for clinical practice is of great importance. Therefore, we have explored the drug repositioning approach to identify candidate modulators of ABCB1 and ABCG2 from tyrosine kinase inhibitors with known pharmacological properties and anticancer activities. In this study, we discovered that avapritinib (BLU-285), a potent, selective, and orally bioavailable tyrosine kinase inhibitor against mutant forms of KIT and platelet-derived growth factor receptor alpha (PDGFRA), attenuates the transport function of both ABCB1 and ABCG2. Moreover, avapritinib restores the chemosensitivity of ABCB1- and ABCG2-overexpressing MDR cancer cells at nontoxic concentrations. These findings were further supported by results of apoptosis induction assays, ATP hydrolysis assays, and docking of avapritinib in the drug-binding pockets of ABCB1 and ABCG2. Altogether, our study highlights an additional action of avapritinib on ABC drug transporters, and a combination of avapritinib with conventional chemotherapy should be further investigated in patients with MDR tumors.
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Affiliation(s)
- Chung-Pu Wu
- Department of Obstetrics and Gynecology , Taipei Chang Gung Memorial Hospital , Taipei 105 , Taiwan
| | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research , National Cancer Institute , Bethesda , Maryland 20892 , United States
| | | | | | | | - Tai-Ho Hung
- Department of Obstetrics and Gynecology , Taipei Chang Gung Memorial Hospital , Taipei 105 , Taiwan
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research , National Cancer Institute , Bethesda , Maryland 20892 , United States
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16
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Abel B, Tosh DK, Durell SR, Murakami M, Vahedi S, Jacobson KA, Ambudkar SV. Evidence for the Interaction of A 3 Adenosine Receptor Agonists at the Drug-Binding Site(s) of Human P-glycoprotein (ABCB1). Mol Pharmacol 2019; 96:180-192. [PMID: 31127007 DOI: 10.1124/mol.118.115295] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 05/16/2019] [Indexed: 12/29/2022] Open
Abstract
P-glycoprotein (P-gp) is a multidrug transporter that is expressed on the luminal surface of epithelial cells in the kidney, intestine, bile-canalicular membrane in the liver, blood-brain barrier, and adrenal gland. This transporter uses energy of ATP hydrolysis to efflux from cells a variety of structurally dissimilar hydrophobic and amphipathic compounds, including anticancer drugs. In this regard, understanding the interaction with P-gp of drug entities in development is important and highly recommended in current US Food and Drug Administration guidelines. Here we tested the P-gp interaction of some A3 adenosine receptor agonists that are being developed for the treatment of chronic diseases, including rheumatoid arthritis, psoriasis, chronic pain, and hepatocellular carcinoma. Biochemical assays of the ATPase activity of P-gp and by photolabeling P-gp with its transport substrate [125I]-iodoarylazidoprazosin led to the identification of rigidified (N)-methanocarba nucleosides (i.e., compound 3 as a stimulator and compound 8 as a partial inhibitor of P-gp ATPase activity). Compound 8 significantly inhibited boron-dipyrromethene (BODIPY)-verapamil transport mediated by human P-gp (IC50 2.4 ± 0.6 µM); however, the BODIPY-conjugated derivative of 8 (compound 24) was not transported by P-gp. In silico docking of compounds 3 and 8 was performed using the recently solved atomic structure of paclitaxel (Taxol)-bound human P-gp. Molecular modeling studies revealed that both compounds 3 and 8 bind in the same region of the drug-binding pocket as Taxol. Thus, this study indicates that nucleoside derivatives can exhibit varied modulatory effects on P-gp activity, depending on structural functionalization. SIGNIFICANCE STATEMENT: Certain A3 adenosine receptor agonists are being developed for the treatment of chronic diseases. The goal of this study was to test the interaction of these agonists with the human multidrug resistance-linked transporter P-glycoprotein (P-gp). ATPase and photolabeling assays demonstrated that compounds with rigidified (N)-methanocarba nucleosides inhibit the activity of P-gp; however, a fluorescent derivative of one of the compounds was not transported by P-gp. Furthermore, molecular docking studies revealed that the binding site for these compounds overlaps with the site for paclitaxel in the drug-binding pocket. These results suggest that nucleoside derivatives, depending on structural functionalization, can modulate the function of P-gp.
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Affiliation(s)
- Biebele Abel
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (B.A., S.R.D., M.M., S.V., S.V.A.), and Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (D.K.T., K.A.J.), National Institutes of Health, Bethesda, Maryland
| | - Dilip K Tosh
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (B.A., S.R.D., M.M., S.V., S.V.A.), and Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (D.K.T., K.A.J.), National Institutes of Health, Bethesda, Maryland
| | - Stewart R Durell
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (B.A., S.R.D., M.M., S.V., S.V.A.), and Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (D.K.T., K.A.J.), National Institutes of Health, Bethesda, Maryland
| | - Megumi Murakami
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (B.A., S.R.D., M.M., S.V., S.V.A.), and Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (D.K.T., K.A.J.), National Institutes of Health, Bethesda, Maryland
| | - Shahrooz Vahedi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (B.A., S.R.D., M.M., S.V., S.V.A.), and Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (D.K.T., K.A.J.), National Institutes of Health, Bethesda, Maryland
| | - Kenneth A Jacobson
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (B.A., S.R.D., M.M., S.V., S.V.A.), and Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (D.K.T., K.A.J.), National Institutes of Health, Bethesda, Maryland
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute (B.A., S.R.D., M.M., S.V., S.V.A.), and Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (D.K.T., K.A.J.), National Institutes of Health, Bethesda, Maryland
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17
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Nandigama K, Lusvarghi S, Shukla S, Ambudkar SV. Large-scale purification of functional human P-glycoprotein (ABCB1). Protein Expr Purif 2019; 159:60-68. [PMID: 30851394 DOI: 10.1016/j.pep.2019.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 02/21/2019] [Accepted: 03/02/2019] [Indexed: 12/27/2022]
Abstract
Human P-glycoprotein (P-gp) is an ATP-binding cassette transporter that has been implicated in altering the pharmacokinetics of anticancer drugs in normal tissues and development of multidrug resistance in tumor cells via drug efflux. There is still no definitive explanation of the mechanism by which P-gp effluxes drugs. One of the challenges of large-scale purification of membrane transporters is the selection of a suitable detergent for its optimal extraction from cell membranes. In addition, further steps of purification can often lead to inactivation and aggregation, decreasing the yield of purified protein. Here we report the large-scale purification of human P-gp expressed in High-Five insect cells using recombinant baculovirus. The purification strategies we present yield homogeneous functionally active wild type P-gp and its E556Q/E1201Q mutant, which is defective in carrying out ATP hydrolysis. Three detergents (1,2-diheptanoyol-sn-glycero-3-phosphocholine, dodecyl maltoside and n-octyl-β-d-glucopyranoside) were used to solubilize and purify P-gp from insect cell membranes. P-gp purification was performed first using immobilized metal affinity chromatography, then followed by a second step of either anion exchange chromatography or size exclusion chromatography to yield protein in concentrations of 2-12 mg/mL. Size exclusion chromatography was the preferred method, as it allows separation of monomeric transporters from aggregates. We show that the purified protein, when reconstituted in proteoliposomes and nanodiscs, exhibits both basal and substrate or inhibitor-modulated ATPase activity. This report thus provides a convenient and robust method to obtain large amounts of active homogeneously purified human P-gp that is suitable for biochemical, biophysical and structural characterization.
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Affiliation(s)
- Krishnamachary Nandigama
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Suneet Shukla
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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18
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Hsiao SH, Lusvarghi S, Huang YH, Ambudkar SV, Hsu SC, Wu CP. The FLT3 inhibitor midostaurin selectively resensitizes ABCB1-overexpressing multidrug-resistant cancer cells to conventional chemotherapeutic agents. Cancer Lett 2019; 445:34-44. [PMID: 30639533 DOI: 10.1016/j.canlet.2019.01.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/28/2018] [Accepted: 01/02/2019] [Indexed: 12/22/2022]
Abstract
The occurrence of multidrug resistance (MDR) associated with the overexpression of the ATP-binding cassette (ABC) protein ABCB1 in cancer cells remains a significant obstacle to successful cancer chemotherapy. Therefore, discovering modulators that are capable of inhibiting the drug efflux function or expression of ABCB1 and re-sensitizing multidrug-resistant cancer cells to anticancer agents is of great clinical importance. Regrettably, due to potential adverse events associated with drug-drug interactions and toxicity in patients, researchers have struggled to develop a synthetic inhibitor of ABCB1 that is clinically applicable to improve the effectiveness of chemotherapy. Alternatively, through drug repositioning of approved drugs, we discovered that the FMS-like tyrosine kinase-3 (FLT3) inhibitor midostaurin blocks the drug transport function of ABCB1 and re-sensitizes ABCB1-overexpressing multidrug-resistant cancer cells to conventional chemotherapeutic drugs. Our findings were further supported by results demonstrating that midostaurin potentiates drug-induced apoptosis in ABCB1-overexpressing cancer cells and inhibits the ATPase activity of ABCB1. Considering that midostaurin is a clinically approved anticancer agent, our findings revealed an additional action of midostaurin and that patients with multidrug-resistant tumors may benefit from a combination therapy of midostaurin with standard chemotherapy, which should be further investigated.
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Affiliation(s)
- Sung-Han Hsiao
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.
| | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States.
| | - Yang-Hui Huang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States.
| | - Sheng-Chieh Hsu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Linkou, Taiwan.
| | - Chung-Pu Wu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Neurosurgery, Chang Gung Memorial Hospital, Linkou, Taiwan.
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19
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Sajid A, Lusvarghi S, Chufan EE, Ambudkar SV. Evidence for the critical role of transmembrane helices 1 and 7 in substrate transport by human P-glycoprotein (ABCB1). PLoS One 2018; 13:e0204693. [PMID: 30265721 PMCID: PMC6161881 DOI: 10.1371/journal.pone.0204693] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/12/2018] [Indexed: 12/15/2022] Open
Abstract
P-glycoprotein (P-gp) is an ABC transporter that exports many amphipathic or hydrophobic compounds, including chemically and functionally dissimilar anticancer drugs, from cells. To understand the role of transmembrane helices (TMH) 1 and 7 in drug-binding and transport, we selected six residues from both TMH1 (V53, I59, I60, L65, M68 and F72) and TMH7 (V713, I719, I720, Q725, F728 and F732); and substituted them with alanine by gene synthesis to generate a variant termed "TMH1,7 mutant P-gp". The expression and function of TMH1,7 mutant P-gp with twelve mutations was characterized using the BacMam baculovirus-HeLa cell expression system. The expression and conformation of TMH1,7 mutant P-gp was not altered by the introduction of the twelve mutations, as confirmed by using the human P-gp-specific antibodies UIC2, MRK16 and 4E3. We tested 25 fluorescently-labeled substrates and found that only three substrates, NBD-cyclosporine A, Rhod-2-AM and X-Rhod-1-AM were transported by the TMH1,7 mutant. The basal ATPase activity of TMH1,7 mutant P-gp was lower (40-50%) compared to wild-type (WT) P-gp, despite similar level of expression. Although most of the substrates modulate ATPase activity of P-gp, the activity of TMH1,7 mutant transporter was not significantly modulated by any of the tested substrates. Docking of selected substrates in homology models showed comparable docking scores for the TMH1,7 mutant and WT P-gp, although the binding conformations were different. Both the ATPase assay and in silico docking analyses suggest that the interactions with residues in the drug-binding pocket are altered as a consequence of the mutations. We demonstrate that it is possible to generate a variant of P-gp with a loss of broad substrate specificity and propose that TMH1 and TMH7 play a critical role in the drug efflux function of this multidrug transporter.
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Affiliation(s)
- Andaleeb Sajid
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Eduardo E. Chufan
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Suresh V. Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
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20
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Hsiao SH, Murakami M, Yeh N, Li YQ, Hung TH, Wu YS, Ambudkar SV, Wu CP. The positive inotropic agent DPI-201106 selectively reverses ABCB1-mediated multidrug resistance in cancer cell lines. Cancer Lett 2018; 434:81-90. [PMID: 30031116 DOI: 10.1016/j.canlet.2018.07.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/13/2018] [Accepted: 07/13/2018] [Indexed: 02/07/2023]
Abstract
The overexpression of ABCB1 in cancer cells is a major factor contributing to the development of multidrug resistance (MDR) and treatment failure in cancer patients. Therefore, re-sensitization of MDR cancer cells to anticancer drugs remains an important aspect in chemotherapy. The progress in developing clinically applicable synthetic inhibitors of ABCB1 has been slow, mostly due to complications associated with intrinsic toxicities and unforeseen drug-drug interactions. Here, we explored the drug-repositioning approach for cancer therapy by targeting ABCB1-mediated MDR in human cancer cells. We found that DPI-201106, a positive inotropic agent, selectively inhibits the drug efflux function of ABCB1, and in doing so, re-sensitizes ABCB1-overexpressing MDR cancer cells to conventional anticancer drugs. Furthermore, the ATPase activity of ABCB1 and docking analysis of DPI-201106 in the drug-binding pocket of ABCB1 were determined to confirm the interaction between DPI-201106 and ABCB1 protein. In summary, we revealed an additional action and a potential clinical application of DPI-201106 to reverse ABCB1-mediated MDR in human cancer cells, which may be beneficial for cancer patients who have developed multidrug resistance and no longer respond to conventional chemotherapy, and should be further investigated.
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Affiliation(s)
- Sung-Han Hsiao
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.
| | - Megumi Murakami
- Laboratory of Cell Biology, CCR, NCI, NIH, Bethesda, United States.
| | - Ni Yeh
- Department of Chemistry, Tunghai University, Taichung, Taiwan.
| | - Yan-Qing Li
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.
| | - Tai-Ho Hung
- Department of Chinese Medicine, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Obstetrics and Gynecology, Taipei Chang Gung Memorial Hospital, Taipei, Taiwan.
| | - Yu-Shan Wu
- Department of Chemistry, Tunghai University, Taichung, Taiwan.
| | | | - Chung-Pu Wu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Neurosurgery, Chang Gung Memorial Hospital, Linkou, Taiwan.
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21
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Park S, Majd S. Reconstitution and functional studies of hamster P-glycoprotein in giant liposomes. PLoS One 2018; 13:e0199279. [PMID: 29912971 PMCID: PMC6005519 DOI: 10.1371/journal.pone.0199279] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 06/05/2018] [Indexed: 11/18/2022] Open
Abstract
This paper describes the preparation of giant unilamellar vesicles with reconstituted hamster P-glycoprotein (Pgp, ABCB1) for studying the transport activity of this efflux pump in individual liposomes using optical microscopy. Pgp, a member of ABC (ATP-binding cassette) transporter family, is known to contribute to the cellular multidrug resistance (MDR) against variety of drugs. The efficacy of many therapeutics is, thus, hampered by this efflux pump, leading to a high demand for simple and effective strategies to monitor the interactions of candidate drugs with this protein. Here, we applied small Pgp proteoliposomes to prepare giant Pgp-bearing liposomes via modified electroformation techniques. The presence of Pgp in the membrane of giant proteoliposomes was confirmed using immunohistochemistry. Assessment of Pgp ATPase activity suggested that this transporter retained its activity upon reconstitution into giant liposomes, with an ATPase specific activity of 439 ± 103 nmol/mg protein/min. For further confirmation, we assessed the transport activity of Pgp in these proteoliposomes by monitoring the translocation of rhodamine 123 (Rho123) across the membrane using confocal microscopy at various ATP concentrations (0-2 mM) and in the presence of Pgp inhibitors. Rate of change in Rho123 concentration inside the liposomal lumen was used to estimate the Rho123 transport rates (1/s) for various ATP concentrations, which were then applied to retrieve the Michaelis-Menten constant (Km) of ATP in Rho123 transport (0.42 ± 0.75 mM). Similarly, inhibitory effects of verapamil, colchicine, and cyclosporin A on Pgp were studied in this system and the IC50 values for these Pgp inhibitors were found 26.6 ± 6.1 μM, 94.6 ± 47.6 μM, and 0.21 ± 0.07 μM, respectively. We further analyzed the transport data using a kinetic model that enabled dissecting the passive diffusion of Rho123 from its Pgp-mediated transport across the membrane. Based on this model, the permeability coefficient of Rho123 across the liposomal membrane was approximately 1.25×10-7 cm/s. Comparing the membrane permeability in liposomes with and without Pgp revealed that the presence of this protein did not have a significant impact on membrane integrity and permeability. Furthermore, we used this model to obtain transport rate constants for the Pgp-mediated transport of Rho123 (m3/mol/s) at various ATP and inhibitor concentrations, which were then applied to estimate values of 0.53 ± 0.66 mM for Km of ATP and 25.2 ± 5.0 μM for verapamil IC50, 61.8 ± 34.8 μM for colchicine IC50, and 0.23 ± 0.09 μM for cyclosporin A IC50. The kinetic parameters obtained from the two analyses were comparable, suggesting a minimal contribution from the passive Rho123 diffusion across the membrane. This approach may, therefore, be applied for screening the transport activity of Pgp against potential drug candidates.
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Affiliation(s)
- SooHyun Park
- The Brown Foundation Institute of Molecular Medicine and Texas Therapeutics Institute, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Sheereen Majd
- Department of Biomedical Engineering, University of Houston, Houston, Texas, United States of America
- * E-mail:
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22
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Kim Y, Chen J. Molecular structure of human P-glycoprotein in the ATP-bound, outward-facing conformation. Science 2018; 359:915-919. [PMID: 29371429 DOI: 10.1126/science.aar7389] [Citation(s) in RCA: 303] [Impact Index Per Article: 50.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 01/16/2018] [Indexed: 12/28/2022]
Abstract
The multidrug transporter permeability (P)-glycoprotein is an adenosine triphosphate (ATP)-binding cassette exporter responsible for clinical resistance to chemotherapy. P-glycoprotein extrudes toxic molecules and drugs from cells through ATP-powered conformational changes. Despite decades of effort, only the structures of the inward-facing conformation of P-glycoprotein are available. Here we present the structure of human P-glycoprotein in the outward-facing conformation, determined by cryo-electron microscopy at 3.4-angstrom resolution. The two nucleotide-binding domains form a closed dimer occluding two ATP molecules. The drug-binding cavity observed in the inward-facing structures is reorientated toward the extracellular space and compressed to preclude substrate binding. This observation indicates that ATP binding, not hydrolysis, promotes substrate release. The structure evokes a model in which the dynamic nature of P-glycoprotein enables translocation of a large variety of substrates.
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Affiliation(s)
- Youngjin Kim
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Jue Chen
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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23
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Global alteration of the drug-binding pocket of human P-glycoprotein (ABCB1) by substitution of fifteen conserved residues reveals a negative correlation between substrate size and transport efficiency. Biochem Pharmacol 2017; 143:53-64. [PMID: 28728917 DOI: 10.1016/j.bcp.2017.07.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 07/13/2017] [Indexed: 11/21/2022]
Abstract
P-glycoprotein (P-gp), an ATP-dependent efflux pump, is linked to the development of multidrug resistance in cancer cells. However, the drug-binding sites and translocation pathways of this transporter are not yet well-characterized. We recently demonstrated the important role of tyrosine residues in regulating P-gp ATP hydrolysis via hydrogen bond formations with high affinity modulators. Since tyrosine is both a hydrogen bond donor and acceptor, and non-covalent interactions are key in drug transport, in this study we investigated the global effect of enrichment of tyrosine residues in the drug-binding pocket on the drug binding and transport function of P-gp. By employing computational analysis, 15 conserved residues in the drug-binding pocket of human P-gp that interact with substrates were identified and then substituted with tyrosine, including 11 phenylalanine (F72, F303, F314, F336, F732, F759, F770, F938, F942, F983, F994), two leucine (L339, L975), one isoleucine (I306), and one methionine (M949). Characterization of the tyrosine-rich P-gp mutant in HeLa cells demonstrated that this major alteration in the drug-binding pocket by introducing fifteen additional tyrosine residues is well tolerated and has no measurable effect on total or cell surface expression of this mutant. Although the tyrosine-enriched mutant P-gp could transport small to moderate size (<1000 Daltons) fluorescent substrates, its ability to transport large (>1000 Daltons) substrates such as NBD-cyclosporine A, Bodipy-paclitaxel and Bodipy-vinblastine was significantly decreased. This was further supported by the physico-chemical characterization of seventeen tested substrates, which revealed a negative correlation between drug transport and molecular size for the tyrosine-enriched P-gp mutant.
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24
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Verhalen B, Dastvan R, Thangapandian S, Peskova Y, Koteiche HA, Nakamoto RK, Tajkhorshid E, Mchaourab HS. Energy transduction and alternating access of the mammalian ABC transporter P-glycoprotein. Nature 2017; 543:738-741. [PMID: 28289287 PMCID: PMC5558441 DOI: 10.1038/nature21414] [Citation(s) in RCA: 170] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 01/23/2017] [Indexed: 12/15/2022]
Abstract
ATP binding cassette (ABC) transporters of the exporter class harness the energy of ATP hydrolysis in the nucleotide-binding domains (NBDs) to power the energetically uphill efflux of substrates by a dedicated transmembrane domain (TMD). Although numerous investigations have described the mechanism of ATP hydrolysis and defined the architecture of ABC exporters, a detailed structural dynamic understanding of the transduction of ATP energy to the work of substrate translocation remains elusive. Here we used double electron-electron resonance and molecular dynamics simulations to describe the ATP- and substrate-coupled conformational cycle of the mouse ABC efflux transporter P-glycoprotein (Pgp; also known as ABCB1), which has a central role in the clearance of xenobiotics and in cancer resistance to chemotherapy. Pairs of spin labels were introduced at residues selected to track the putative inward-facing to outward-facing transition. Our findings illuminate how ATP energy is harnessed in the NBDs in a two-stroke cycle and elucidate the consequent conformational motion that reconfigures the TMD, two critical aspects of Pgp transport mechanism. Along with a fully atomistic model of the outward-facing conformation in membranes, the insight into Pgp conformational dynamics harmonizes mechanistic and structural data into a novel perspective on ATP-coupled transport and reveals mechanistic divergence within the efflux class of ABC transporters.
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Affiliation(s)
- Brandy Verhalen
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Reza Dastvan
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Sundarapandian Thangapandian
- Department of Biochemistry, Center for Biophysics and Quantitative Biology, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Yelena Peskova
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Hanane A Koteiche
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Robert K Nakamoto
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Emad Tajkhorshid
- Department of Biochemistry, Center for Biophysics and Quantitative Biology, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232, USA
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25
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Shukla S, Abel B, Chufan EE, Ambudkar SV. Effects of a detergent micelle environment on P-glycoprotein (ABCB1)-ligand interactions. J Biol Chem 2017; 292:7066-7076. [PMID: 28283574 DOI: 10.1074/jbc.m116.771634] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 03/06/2017] [Indexed: 11/06/2022] Open
Abstract
P-glycoprotein (P-gp) is a multidrug transporter that uses energy from ATP hydrolysis to export many structurally dissimilar hydrophobic and amphipathic compounds, including anticancer drugs from cells. Several structural studies on purified P-gp have been reported, but only limited and sometimes conflicting information is available on ligand interactions with the isolated transporter in a dodecyl-maltoside detergent environment. In this report we compared the biochemical properties of P-gp in native membranes, detergent micelles, and when reconstituted in artificial membranes. We found that the modulators zosuquidar, tariquidar, and elacridar stimulated the ATPase activity of purified human or mouse P-gp in a detergent micelle environment. In contrast, these drugs inhibited ATPase activity in native membranes or in proteoliposomes, with IC50 values in the 10-40 nm range. Similarly, a 30-150-fold decrease in the apparent affinity for verapamil and cyclic peptide inhibitor QZ59-SSS was observed in detergent micelles compared with native or artificial membranes. Together, these findings demonstrate that the high-affinity site is inaccessible because of either a conformational change or binding of detergent at the binding site in a detergent micelle environment. The ligands bind to a low-affinity site, resulting in altered modulation of P-gp ATPase activity. We, therefore, recommend studying structural and functional aspects of ligand interactions with purified P-gp and other ATP-binding cassette transporters that transport amphipathic or hydrophobic substrates in a detergent-free native or artificial membrane environment.
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Affiliation(s)
- Suneet Shukla
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Biebele Abel
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Eduardo E Chufan
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Suresh V Ambudkar
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
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26
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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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27
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Frank GA, Shukla S, Rao P, Borgnia MJ, Bartesaghi A, Merk A, Mobin A, Esser L, Earl LA, Gottesman MM, Xia D, Ambudkar SV, Subramaniam S. Cryo-EM Analysis of the Conformational Landscape of Human P-glycoprotein (ABCB1) During its Catalytic Cycle. Mol Pharmacol 2016; 90:35-41. [PMID: 27190212 PMCID: PMC4931865 DOI: 10.1124/mol.116.104190] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/05/2016] [Indexed: 11/22/2022] Open
Abstract
The multidrug transporter P-glycoprotein (P-gp, ABCB1) is an ATP-dependent pump that mediates the efflux of structurally diverse drugs and xenobiotics across cell membranes, affecting drug pharmacokinetics and contributing to the development of multidrug resistance. Structural information about the conformational changes in human P-gp during the ATP hydrolysis cycle has not been directly demonstrated, although mechanistic information has been inferred from biochemical and biophysical studies conducted with P-gp and its orthologs, or from structures of other ATP-binding cassette transporters. Using single-particle cryo-electron microscopy, we report the surprising discovery that, in the absence of the transport substrate and nucleotides, human P-gp can exist in both open [nucleotide binding domains (NBDs) apart; inward-facing] and closed (NBDs close; outward-facing) conformations. We also probe conformational states of human P-gp during the catalytic cycle, and demonstrate that, following ATP hydrolysis, P-gp transitions through a complete closed conformation to a complete open conformation in the presence of ADP.
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Affiliation(s)
- Gabriel A Frank
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Suneet Shukla
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Prashant Rao
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Mario J Borgnia
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Alberto Bartesaghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Alan Merk
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Aerfa Mobin
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Lothar Esser
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Lesley A Earl
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Michael M Gottesman
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Di Xia
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Sriram Subramaniam
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
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28
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Drug-protein hydrogen bonds govern the inhibition of the ATP hydrolysis of the multidrug transporter P-glycoprotein. Biochem Pharmacol 2015; 101:40-53. [PMID: 26686578 DOI: 10.1016/j.bcp.2015.12.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 12/09/2015] [Indexed: 01/11/2023]
Abstract
P-glycoprotein (P-gp) is a member of the ATP-binding cassette transporter superfamily. This multidrug transporter utilizes energy from ATP hydrolysis for the efflux of a variety of hydrophobic and amphipathic compounds including anticancer drugs. Most of the substrates and modulators of P-gp stimulate its basal ATPase activity, although some inhibit it. The molecular mechanisms that are in play in either case are unknown. In this report, mutagenesis and molecular modeling studies of P-gp led to the identification of a pair of phenylalanine-tyrosine structural motifs in the transmembrane region that mediate the inhibition of ATP hydrolysis by certain drugs (zosuquidar, elacridar and tariquidar), with high affinity (IC50's ranging from 10 to 30nM). Upon mutation of any of these residues, drugs that inhibit the ATPase activity of P-gp switch to stimulation of the activity. Molecular modeling revealed that the phenylalanine residues F978 and F728 interact with tyrosine residues Y953 and Y310, respectively, in an edge-to-face conformation, which orients the tyrosines in such a way that they establish hydrogen-bond contacts with the inhibitor. Biochemical investigations along with transport studies in intact cells showed that the inhibitors bind at a high affinity site to produce inhibition of ATP hydrolysis and transport function. Upon mutation, they bind at lower affinity sites, stimulating ATP hydrolysis and only poorly inhibiting transport. These results also reveal that screening chemical compounds for their ability to inhibit the basal ATP hydrolysis can be a reliable tool to identify modulators with high affinity for P-gp.
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29
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Chufan EE, Sim HM, Ambudkar SV. Molecular basis of the polyspecificity of P-glycoprotein (ABCB1): recent biochemical and structural studies. Adv Cancer Res 2015; 125:71-96. [PMID: 25640267 DOI: 10.1016/bs.acr.2014.10.003] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
ABCB1 (P-glycoprotein/P-gp) is an ATP-binding cassette transporter well known for its association with multidrug resistance in cancer cells. Powered by the hydrolysis of ATP, it effluxes structurally diverse compounds. In this chapter, we discuss current views on the molecular basis of the substrate polyspecificity of P-gp. One of the features that accounts for this property is the structural flexibility observed in P-gp. Several X-ray crystal structures of mouse P-gp have been published recently in the absence of nucleotide, with and without bound inhibitors. All the structures are in an inward-facing conformation exhibiting different degrees of domain separation, thus revealing a highly flexible protein. Biochemical and biophysical studies also demonstrate this flexibility in mouse as well as human P-gp. Site-directed mutagenesis has revealed the existence of multiple transport-active binding sites in P-gp for a single substrate. Thus, drugs can bind at either primary or secondary sites. Biochemical, molecular modeling, and structure-activity relationship studies suggest a large, common drug-binding pocket with overlapping sites for different substrates. We propose that in addition to the structural flexibility, the molecular or chemical flexibility also contributes to the binding of substrates to multiple sites forming the basis of polyspecificity.
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Affiliation(s)
- Eduardo E Chufan
- Center for Cancer Research, Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Hong-May Sim
- Center for Cancer Research, Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Suresh V Ambudkar
- Center for Cancer Research, Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
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30
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Scian M, Acchione M, Li M, Atkins WM. Reaction dynamics of ATP hydrolysis catalyzed by P-glycoprotein. Biochemistry 2014; 53:991-1000. [PMID: 24506763 PMCID: PMC3985762 DOI: 10.1021/bi401280v] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
![]()
P-glycoprotein
(P-gp) is a member of the ABC transporter family
that confers drug resistance to many tumors by catalyzing their efflux,
and it is a major component of drug–drug interactions. P-gp
couples drug efflux with ATP hydrolysis by coordinating conformational
changes in the drug binding sites with the hydrolysis of ATP and release
of ADP. To understand the relative rates of the chemical step for
hydrolysis and the conformational changes that follow it, we exploited
isotope exchange methods to determine the extent to which the ATP
hydrolysis step is reversible. With γ18O4-labeled ATP, no positional isotope exchange is detectable at the
bridging β-phosphorus–O−γ-phosphorus bond.
Furthermore, the phosphate derived from hydrolysis includes a constant
ratio of three 18O/two 18O/one 18O that reflects the isotopic composition of the starting ATP in multiple
experiments. Thus, H2O-exchange with HPO42– (Pi) was negligible, suggesting that a
[P-gp·ADP·Pi] is not long-lived. This further
demonstrates that the hydrolysis is essentially irreversible in the
active site. These mechanistic details of ATP hydrolysis are consistent
with a very fast conformational change immediately following, or concomitant
with, hydrolysis of the γ-phosphate linkage that ensures a high
commitment to catalysis in both drug-free and drug-bound states.
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Affiliation(s)
- Michele Scian
- Department of Medicinal Chemistry, University of Washington , Box 357610, Seattle, Washington 98195-7610, United States
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Chufan EE, Kapoor K, Sim HM, Singh S, Talele TT, Durell SR, Ambudkar SV. Multiple transport-active binding sites are available for a single substrate on human P-glycoprotein (ABCB1). PLoS One 2013; 8:e82463. [PMID: 24349290 PMCID: PMC3857843 DOI: 10.1371/journal.pone.0082463] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/24/2013] [Indexed: 01/07/2023] Open
Abstract
P-glycoprotein (Pgp, ABCB1) is an ATP-Binding Cassette (ABC) transporter that is associated with the development of multidrug resistance in cancer cells. Pgp transports a variety of chemically dissimilar amphipathic compounds using the energy from ATP hydrolysis. In the present study, to elucidate the binding sites on Pgp for substrates and modulators, we employed site-directed mutagenesis, cell- and membrane-based assays, molecular modeling and docking. We generated single, double and triple mutants with substitutions of the Y307, F343, Q725, F728, F978 and V982 residues at the proposed drug-binding site with cys in a cysless Pgp, and expressed them in insect and mammalian cells using a baculovirus expression system. All the mutant proteins were expressed at the cell surface to the same extent as the cysless wild-type Pgp. With substitution of three residues of the pocket (Y307, Q725 and V982) with cysteine in a cysless Pgp, QZ59S-SSS, cyclosporine A, tariquidar, valinomycin and FSBA lose the ability to inhibit the labeling of Pgp with a transport substrate, [125I]-Iodoarylazidoprazosin, indicating these drugs cannot bind at their primary binding sites. However, the drugs can modulate the ATP hydrolysis of the mutant Pgps, demonstrating that they bind at secondary sites. In addition, the transport of six fluorescent substrates in HeLa cells expressing triple mutant (Y307C/Q725C/V982C) Pgp is also not significantly altered, showing that substrates bound at secondary sites are still transported. The homology modeling of human Pgp and substrate and modulator docking studies support the biochemical and transport data. In aggregate, our results demonstrate that a large flexible pocket in the Pgp transmembrane domains is able to bind chemically diverse compounds. When residues of the primary drug-binding site are mutated, substrates and modulators bind to secondary sites on the transporter and more than one transport-active binding site is available for each substrate.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 1/chemistry
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Adenosine Triphosphatases/metabolism
- Adenosine Triphosphate/metabolism
- Binding Sites
- Cell Line, Tumor
- Fluorescent Dyes/chemistry
- Fluorescent Dyes/metabolism
- Gene Expression
- HeLa Cells
- Humans
- Hydrolysis
- Models, Molecular
- Molecular Docking Simulation
- Mutagenesis, Site-Directed
- Protein Binding
- Protein Conformation
- Protein Interaction Domains and Motifs
- Transduction, Genetic
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Affiliation(s)
- Eduardo E. Chufan
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Khyati Kapoor
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hong-May Sim
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Satyakam Singh
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John’s University, Queens, New York, United States of America
| | - Tanaji T. Talele
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John’s University, Queens, New York, United States of America
| | - Stewart R. Durell
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Suresh V. Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Sim HM, Bhatnagar J, Chufan EE, Kapoor K, Ambudkar SV. Conserved Walker A cysteines 431 and 1074 in human P-glycoprotein are accessible to thiol-specific agents in the apo and ADP-vanadate trapped conformations. Biochemistry 2013; 52:7327-38. [PMID: 24053441 PMCID: PMC3850068 DOI: 10.1021/bi4007786] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
P-Glycoprotein (P-gp) is an ATP-binding cassette efflux transporter involved in the development of multidrug resistance in cancer cells. Although the mechanism of P-gp efflux has been extensively studied, aspects of its catalytic and transport cycle are still unclear. In this study, we used conserved C431 and C1074 in the Walker A motif of nucleotide-binding domains (NBDs) as reporter sites to interrogate the interaction between the two NBDs during the catalytic cycle. Disulfide cross-linking of the C431 and C1074 residues in a Cys-less background can be observed in the presence of M14M and M17M cross-linkers, which have spacer arm lengths of 20 and 25 Å, respectively. However, cross-linking with both cross-linkers was prevented in the ADP-vanadate trapped (closed) conformation. Both C431 and C1074 alone or together (double mutant) in the apo and closed conformations were found to be accessible to fluorescein 5-maleimide (FM) and methanethiosulfonate derivatives of rhodamine and verapamil. In addition, C1074 showed 1.4- and 2-fold higher degrees of FM labeling than C431 in the apo and closed conformations, respectively, demonstrating that C1074 is more accessible than C431 in both conformations. In the presence of P-gp substrates, cross-linking with M17M is still observed, suggesting that binding of substrate in the transmembrane domains does not change the accessibility of the cysteines in the NBDs. In summary, the cysteines in the Walker A motifs of NBDs of human P-gp are differentially accessible to thiol-specific agents in the apo and closed conformations.
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Affiliation(s)
- Hong-May Sim
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2085, USA
| | - Jaya Bhatnagar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2085, USA
| | - Eduardo E. Chufan
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2085, USA
| | - Khyati Kapoor
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2085, USA
| | - Suresh V. Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 2085, USA
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Kapoor K, Bhatnagar J, Chufan EE, Ambudkar SV. Mutations in intracellular loops 1 and 3 lead to misfolding of human P-glycoprotein (ABCB1) that can be rescued by cyclosporine A, which reduces its association with chaperone Hsp70. J Biol Chem 2013; 288:32622-32636. [PMID: 24064216 DOI: 10.1074/jbc.m113.498980] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
P-glycoprotein (P-gp) is an ATP binding cassette transporter that effluxes a variety of structurally diverse compounds including anticancer drugs. Computational models of human P-gp in the apo- and nucleotide-bound conformation show that the adenine group of ATP forms hydrogen bonds with the conserved Asp-164 and Asp-805 in intracellular loops 1 and 3, respectively, which are located at the interface between the nucleotide binding domains and transmembrane domains. We investigated the role of Asp-164 and Asp-805 residues by substituting them with cysteine in a cysteine-less background. It was observed that the D164C/D805C mutant, when expressed in HeLa cells, led to misprocessing of P-gp, which thus failed to transport the drug substrates. The misfolded protein could be rescued to the cell surface by growing the cells at a lower temperature (27 °C) or by treatment with substrates (cyclosporine A, FK506), modulators (tariquidar), or small corrector molecules. We also show that short term (4-6 h) treatment with 15 μM cyclosporine A or FK506 rescues the pre-formed immature protein trapped in the endoplasmic reticulum in an immunophilin-independent pathway. The intracellularly trapped misprocessed protein associates more with chaperone Hsp70, and the treatment with cyclosporine A reduces the association of mutant P-gp, thus allowing it to be trafficked to the cell surface. The function of rescued cell surface mutant P-gp is similar to that of wild-type protein. These data demonstrate that the Asp-164 and Asp-805 residues are not important for ATP binding, as proposed earlier, but are critical for proper folding and maturation of a functional transporter.
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Affiliation(s)
- Khyati Kapoor
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892-4256
| | - Jaya Bhatnagar
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892-4256
| | - Eduardo E Chufan
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892-4256
| | - Suresh V Ambudkar
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892-4256.
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Bhullar J, Natarajan K, Shukla S, Mathias TJ, Sadowska M, Ambudkar SV, Baer MR. The FLT3 inhibitor quizartinib inhibits ABCG2 at pharmacologically relevant concentrations, with implications for both chemosensitization and adverse drug interactions. PLoS One 2013; 8:e71266. [PMID: 23967177 PMCID: PMC3743865 DOI: 10.1371/journal.pone.0071266] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 06/27/2013] [Indexed: 11/19/2022] Open
Abstract
The oral second-generation bis-aryl urea fms-like tyrosine kinase 3 (FLT3) inhibitor quizartinib (AC220) has favorable kinase selectivity and pharmacokinetics. It inhibits mutant and wild-type FLT3 in vivo at 0.1 and 0.5 µM, respectively, and has shown favorable activity and tolerability in phase I and II trials in acute myeloid leukemia, with QT prolongation as the dose-limiting toxicity. Co-administration with chemotherapy is planned. We characterized interactions of quizartinib with the ATP-binding cassette (ABC) proteins ABCB1 (P-glycoprotein) and ABCG2 (breast cancer resistance protein). Its effects on uptake of fluorescent substrates and apoptosis were measured by flow cytometry, binding to ABCB1 and ABCG2 drug-binding sites by effects on [¹²⁵I]iodoarylazidoprazosin ([¹²⁵I]-IAAP) photolabeling and ATPase activity, and cell viability by the WST-1 colorimetric assay. Quizartinib inhibited transport of fluorescent ABCG2 and ABCB1 substrates in ABCG2- and ABCB1-overexpressing cells in a concentration-dependent manner, from 0.1 to 5 µM and from 0.5 to 10 µM, respectively, and inhibited [¹²⁵I]-IAAP photolabeling of ABCG2 and ABCB1 with IC₅₀ values of 0.07 and 3.3 µM, respectively. Quizartinib at higher concentrations decreased ABCG2, but not ABCB1, ATPase activity. Co-incubation with quizartinib at 0.1 to 1 µM sensitized ABCG2-overexpressing K562/ABCG2 and 8226/MR20 cells to ABCG2 substrate chemotherapy drugs in a concentration-dependent manner in cell viability and apoptosis assays. Additionally, quizartinib increased cellular uptake of the ABCG2 substrate fluoroquinolone antibiotic ciprofloxacin, which also prolongs the QT interval, in a concentration-dependent manner, predicting altered ciprofloxacin pharmacokinetics and pharmacodynamics when co-administered with quizartinib. Thus quizartinib inhibits ABCG2 at pharmacologically relevant concentrations, with implications for both chemosensitization and adverse drug interactions. These interactions should be considered in the design of treatment regimens combining quizartinib and chemotherapy drugs and in choice of concomitant medications to be administered with quizartinib.
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Affiliation(s)
- Jasjeet Bhullar
- Greenebaum Cancer Center, University of Maryland, Baltimore, Maryland, United States of America
| | - Karthika Natarajan
- Greenebaum Cancer Center, University of Maryland, Baltimore, Maryland, United States of America
| | - Suneet Shukla
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Trevor J. Mathias
- Greenebaum Cancer Center, University of Maryland, Baltimore, Maryland, United States of America
| | - Mariola Sadowska
- Greenebaum Cancer Center, University of Maryland, Baltimore, Maryland, United States of America
| | - Suresh V. Ambudkar
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Maria R. Baer
- Greenebaum Cancer Center, University of Maryland, Baltimore, Maryland, United States of America
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Beck A, Aänismaa P, Li-Blatter X, Dawson R, Locher K, Seelig A. Sav1866 from Staphylococcus aureus and P-glycoprotein: similarities and differences in ATPase activity assessed with detergents as allocrites. Biochemistry 2013; 52:3297-309. [PMID: 23600489 DOI: 10.1021/bi400203d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ATP-binding cassette exporters Sav1866 from Staphylococcus aureus and P-glycoprotein are known to share a certain sequence similarity and disposition for cationic allocrites. Conversely, the two ATPases react very differently to neutral detergents that have previously been shown to be inhibitory allocrites for P-glycoprotein. To gain insight into the functional differences of the two proteins, we compared their basal and detergent-stimulated ATPase activity. P-Glycoprotein was investigated in NIH-MDR1-G185 plasma membrane vesicles and Sav1866 in lipid vesicles exhibiting a membrane packing density and a surface potential similar to those of the plasma membrane vesicles. Under basal conditions, Sav1866 revealed a lower catalytic efficiency and concomitantly a more pronounced sodium chloride and pH dependence than P-glycoprotein. As expected, the cationic allocrites (alkyltrimethylammonium chlorides) induced similar bell-shaped activity curves as a function of concentration for both exporters, suggesting stimulation upon binding of the first and inhibition upon binding of the second allocrite molecule. However, the neutral allocrites (n-alkyl-β-d-maltosides and n-ethylene glycol monododecyl ethers) reduced P-glycoprotein's ATPase activity at concentrations well below their critical micelle concentration (CMC) but strongly enhanced Sav1866's ATPase activity even at concentrations above their CMC. The lack of ATPase inhibition at high concentrations of neutral of detergents could be explained by their comparatively low binding affinity for the transmembrane domains of Sav1866, which seems to prevent binding of a second inhibitory molecule. The high ATPase activity in the presence of hydrophobic, long chain detergents moreover revealed that Sav1866, despite its lower basal catalytic efficiency, is a more efficient floppase for lipidlike amphiphiles than P-glycoprotein.
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Affiliation(s)
- Andreas Beck
- Biozentrum, University of Basel , Division of Biophysical Chemistry, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
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Multidrug Resistance in Cancer: A Tale of ABC Drug Transporters. RESISTANCE TO TARGETED ANTI-CANCER THERAPEUTICS 2013. [DOI: 10.1007/978-1-4614-7070-0_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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37
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Zhang DM, Shu C, Chen JJ, Sodani K, Wang J, Bhatnagar J, Lan P, Ruan ZX, Xiao ZJ, Ambudkar SV, Chen WM, Chen ZS, Ye WC. BBA, a derivative of 23-hydroxybetulinic acid, potently reverses ABCB1-mediated drug resistance in vitro and in vivo. Mol Pharm 2012; 9:3147-59. [PMID: 23046348 PMCID: PMC8375564 DOI: 10.1021/mp300249s] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
23-O-(1,4'-Bipiperidine-1-carbonyl)betulinic acid (BBA), a synthetic derivative of 23-hydroxybetulinic acid (23-HBA), shows a reversal effect on multidrug resistance (MDR) in our preliminary screening. Overexpression of ATP-binding cassette (ABC) transporters such as ABCB1, ABCG2, and ABCC1 has been reported in recent studies to be a major factor contributing to MDR. Our study results showed that BBA enhanced the cytotoxicity of ABCB1 substrates and increased the accumulation of doxorubicin or rhodamine123 in ABCB1 overexpressing cells, but had no effect on non ABCB1 substrate, such as cisplatin; what's more, BBA slightly reversed ABCG2-mediated resistance to SN-38, but did not affect the ABCC1-mediated MDR. Further studies on the mechanism indicated that BBA did not alter the expression of ABCB1 at mRNA or protein levels, but affected the ABCB1 ATPase activity by stimulating the basal activity at lower concentrations and inhibiting the activity at higher concentrations. In addition, BBA inhibited the verapamil-stimulated ABCB1 ATPase activity and the photolabeling of ABCB1 with [(125)I] iodoarylazidoprazosin in a concentration-dependent manner, indicating that BBA directly interacts with ABCB1. The docking study confirmed this notion that BBA could bind to the drug binding site(s) on ABCB1, but its binding position was only partially overlapping with that of verapamil or iodoarylazidoprazosin. Importantly, BBA increased the inhibitory effect of paclitaxel in ABCB1 overexpressing KB-C2 cell xenografts in nude mice. Taken together, our findings suggest that BBA can reverse ABCB1-mediated MDR by inhibiting its efflux function of ABCB1, which supports the development of BBA as a novel potential MDR reversal agent used in the clinic.
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Affiliation(s)
- Dong-Mei Zhang
- College of Pharmacy, Jinan University, Guangzhou 510632, China
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Malofeeva EV, Domanitskaya N, Gudima M, Hopper-Borge EA. Modulation of the ATPase and transport activities of broad-acting multidrug resistance factor ABCC10 (MRP7). Cancer Res 2012; 72:6457-67. [PMID: 23087055 DOI: 10.1158/0008-5472.can-12-1340] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The cell surface molecule ABCC10 is a broad-acting transporter of xenobiotics, including cancer drugs, such as taxanes, epothilone B, and modulators of the estrogen pathway. Abcc10(-/-) mice exhibit increased tissue sensitivity and lethality resulting from paclitaxel exposure compared with wild-type counterparts, arguing ABCC10 functions as a major determinant of taxane sensitivity in mice. To better understand the mechanistic basis of ABCC10 action, we characterized the biochemical and vectorial transport properties of this protein. Using crude membranes in an ABCC10 overexpression system, we found that the ABCC10 transport substrates estrogen estradiol-glucuronide (E(2)17βG) and leukotriene C4 (LTC(4)) significantly stimulated ABCC10 beryllium fluoride (BeFx)-sensitive ATPase activity. We also defined the E(2)17βG antagonist, tamoxifen, as a novel substrate and stimulator of ABCC10. In addition, a number of cytotoxic substrates, including docetaxel, paclitaxel, and Ara-C, increased the ABCC10 basal ATPase activity. We determined that ABCC10 localizes to the basolateral cell surface, using transepithelial well assays to establish that ABCC10-overexpressing LLC-PK1 cells exported [(3)H]-docetaxel from the apical to the basolateral side. Importantly, we found that the clinically valuable multikinase inhibitor sorafenib, and a natural alkaloid, cepharanthine, inhibited ABCC10 docetaxel transport activity. Thus, concomitant use of these agents might restore the intracellular accumulation and potency of ABCC10-exported cytotoxic drugs, such as paclitaxel. Overall, our work could seed future efforts to identify inhibitors and other physiologic substrates of ABCC10.
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Affiliation(s)
- Ekaterina V Malofeeva
- Program in Developmental Therapeutics, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA
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Shukla S, Schwartz C, Kapoor K, Kouanda A, Ambudkar SV. Use of baculovirus BacMam vectors for expression of ABC drug transporters in mammalian cells. Drug Metab Dispos 2011; 40:304-12. [PMID: 22041108 DOI: 10.1124/dmd.111.042721] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
ATP-binding cassette (ABC) drug transporters ABCB1 [P-glycoprotein (Pgp)] and ABCG2 are expressed in many tissues including those of the intestines, the liver, the kidney and the brain and are known to influence the pharmacokinetics and toxicity of therapeutic drugs. In vitro studies involving their functional characteristics provide important information that allows improvements in drug delivery or drug design. In this study, we report use of the BacMam (baculovirus-based expression in mammalian cells) expression system to express and characterize the function of Pgp and ABCG2 in mammalian cell lines. BacMam-Pgp and BacMam-ABCG2 baculovirus-transduced cell lines showed similar cell surface expression (as detected by monoclonal antibodies with an external epitope) and transport function of these transporters compared to drug-resistant cell lines that overexpress the two transporters. Transient expression of Pgp was maintained in HeLa cells for up to 72 h after transduction (48 h after removal of the BacMam virus). These BacMam-baculovirus-transduced mammalian cells expressing Pgp or ABCG2 were used for assessing the functional activity of these transporters. Crude membranes isolated from these cells were further used to study the activity of these transporters by biochemical techniques such as photo-cross-linking with transport substrate and adenosine triphosphatase assays. In addition, we show that the BacMam expression system can be exploited to coexpress both Pgp and ABCG2 in mammalian cells to determine their contribution to the transport of a common anticancer drug substrate. Collectively, these data demonstrate that the BacMam-baculovirus-based expression system can be used to simultaneously study the transport function and biochemical properties of ABC transporters.
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Affiliation(s)
- Suneet Shukla
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Ohnuma S, Chufan E, Nandigama K, Miller Jenkins LM, Durell SR, Appella E, Sauna ZE, Ambudkar SV. Inhibition of multidrug resistance-linked P-glycoprotein (ABCB1) function by 5'-fluorosulfonylbenzoyl 5'-adenosine: evidence for an ATP analogue that interacts with both drug-substrate-and nucleotide-binding sites. Biochemistry 2011; 50:3724-35. [PMID: 21452853 PMCID: PMC3108491 DOI: 10.1021/bi200073f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
5'-Fluorosulfonylbenzonyl 5'-adenosine (FSBA) is an ATP analogue that covalently modifies several residues in the nucleotide-binding domains (NBDs) of several ATPases, kinases, and other proteins. P-glycoprotein (P-gp, ABCB1) is a member of the ATP-binding cassette (ABC) transporter superfamily that utilizes energy from ATP hydrolysis for the efflux of amphipathic anticancer agents from cancer cells. We investigated the interactions of FSBA with P-gp to study the catalytic cycle of ATP hydrolysis. Incubation of P-gp with FSBA inhibited ATP hydrolysis (IC(50 )= 0.21 mM) and the binding of 8-azido[α-(32)P]ATP (IC(50) = 0.68 mM). In addition, (14)C-FSBA cross-links to P-gp, suggesting that FSBA-mediated inhibition of ATP hydrolysis is irreversible due to covalent modification of P-gp. However, when the NBDs were occupied with a saturating concentration of ATP prior to treatment, FSBA stimulated ATP hydrolysis by P-gp. Furthermore, FSBA inhibited the photo-cross-linking of P-gp with [(125)I]iodoarylazidoprazosin (IAAP; IC(50) = 0.17 mM). As IAAP is a transport substrate for P-gp, this suggests that FSBA affects not only the NBDs but also the transport-substrate site in the transmembrane domains. Consistent with these results, FSBA blocked efflux of rhodamine 123 from P-gp-expressing cells. Additionally, mass spectrometric analysis identified FSBA cross-links to residues within or nearby the NBDs but not in the transmembrane domains, and docking of FSBA in a homology model of human P-gp NBDs supports the biochemical studies. Thus, FSBA is an ATP analogue that interacts with both the drug-binding and ATP-binding sites of P-gp, but fluorosulfonyl-mediated cross-linking is observed only at the NBDs.
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Affiliation(s)
- Shinobu Ohnuma
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4256
| | - Eduardo Chufan
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4256
| | - Krishnamachary Nandigama
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4256
| | - Lisa M. Miller Jenkins
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4256
| | - Stewart R. Durell
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4256
| | - Ettore Appella
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4256
| | - Zuben E. Sauna
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, Maryland 20892
| | - Suresh V. Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4256
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41
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Nyathi Y, De Marcos Lousa C, van Roermund CW, Wanders RJA, Johnson B, Baldwin SA, Theodoulou FL, Baker A. The Arabidopsis peroxisomal ABC transporter, comatose, complements the Saccharomyces cerevisiae pxa1 pxa2Delta mutant for metabolism of long-chain fatty acids and exhibits fatty acyl-CoA-stimulated ATPase activity. J Biol Chem 2010; 285:29892-902. [PMID: 20659892 PMCID: PMC2943281 DOI: 10.1074/jbc.m110.151225] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 07/08/2010] [Indexed: 12/26/2022] Open
Abstract
The Arabidopsis ABC transporter Comatose (CTS; AtABCD1) is required for uptake into the peroxisome of a wide range of substrates for β-oxidation, but it is uncertain whether CTS itself is the transporter or if the transported substrates are free acids or CoA esters. To establish a system for its biochemical analysis, CTS was expressed in Saccharomyces cerevisiae. The plant protein was correctly targeted to yeast peroxisomes, was assembled into the membrane with its nucleotide binding domains in the cytosol, and exhibited basal ATPase activity that was sensitive to aluminum fluoride and abrogated by mutation of a conserved Walker A motif lysine residue. The yeast pxa1 pxa2Δ mutant lacks the homologous peroxisomal ABC transporter and is unable to grow on oleic acid. Consistent with its exhibiting a function in yeast akin to that in the plant, CTS rescued the oleate growth phenotype of the pxa1 pxa2Δ mutant, and restored β-oxidation of fatty acids with a range of chain lengths and varying degrees of desaturation. When expressed in yeast peroxisomal membranes, the basal ATPase activity of CTS could be stimulated by fatty acyl-CoAs but not by fatty acids. The implications of these findings for the function and substrate specificity of CTS are discussed.
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Affiliation(s)
- Yvonne Nyathi
- From the Centre for Plant Sciences, Faculty of Biological Sciences, and
| | | | - Carlo W. van Roermund
- the Departments of Pediatrics and Clinical Chemistry, Laboratory of Genetic Metabolic Diseases, Academic Medical Centre, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands, and
| | - Ronald J. A. Wanders
- the Departments of Pediatrics and Clinical Chemistry, Laboratory of Genetic Metabolic Diseases, Academic Medical Centre, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands, and
| | - Barbara Johnson
- From the Centre for Plant Sciences, Faculty of Biological Sciences, and
| | - Stephen A. Baldwin
- the Institute of Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | - Alison Baker
- From the Centre for Plant Sciences, Faculty of Biological Sciences, and
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Xie Y, Burcu M, Linn DE, Qiu Y, Baer MR. Pim-1 kinase protects P-glycoprotein from degradation and enables its glycosylation and cell surface expression. Mol Pharmacol 2010; 78:310-8. [PMID: 20460432 PMCID: PMC11037423 DOI: 10.1124/mol.109.061713] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2009] [Accepted: 05/11/2010] [Indexed: 12/28/2022] Open
Abstract
The oncogenic serine/threonine kinase Pim-1 phosphorylates and activates the ATP-binding cassette transporter breast cancer resistance protein (ABCG2). The ABC transporter P-glycoprotein (Pgp; ABCB1) also contains a Pim-1 phosphorylation consensus sequence, and we hypothesized that Pim-1 also regulates Pgp. Pgp is exported from the endoplasmic reticulum (ER) as a 150-kDa species that is glycosylated to 170-kDa Pgp, translocates to the cell surface, and mediates drug efflux; alternatively, 150-kDa Pgp is cleaved to a 130-kDa proteolytic product by ER proteases or undergoes ubiquitination and proteasomal degradation. Pim-1 and Pgp interaction was studied in GST pull-down and phosphorylation in in vitro kinase assays. Pim-1 knockdown and inhibition effects on Pgp expression were studied by immunoblotting and flow cytometry and on Pgp stability by immunoblotting after cycloheximide treatment. Pim-1 directly interacted with and phosphorylated Pgp in intact cells and in vitro. Pim-1 knockdown or inhibition decreased cellular and cell surface 170-kDa Pgp, in association with both transient increase in 130-kDa Pgp and increased Pgp ubiquitination and proteasomal degradation. Pim-1 inhibition also decreased expression of 150-kDa Pgp in the presence of the glycosylation inhibitor 2-deoxy-d-glucose. Finally, Pim-1 inhibition sensitized Pgp-overexpressing cells to doxorubicin. Thus, Pim-1 regulates Pgp expression by protecting 150-kDa Pgp from proteolytic and proteasomal degradation and enabling Pgp glycosylation and cell surface translocation and thus Pgp-mediated drug efflux. Pim-1 inhibitors are entering clinical trials and may provide a novel approach to abrogating drug resistance.
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Affiliation(s)
- Yingqiu Xie
- University of Maryland Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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43
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Ford RC, Kamis AB, Kerr ID, Callaghan R. The ABC Transporters: Structural Insights into Drug Transport. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/9783527627424.ch1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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44
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Choi JS, Kang NS, Min YK, Kim SH. Euphorbiasteroid reverses P-glycoprotein-mediated multi-drug resistance in human sarcoma cell line MES-SA/Dx5. Phytother Res 2009; 24:1042-6. [DOI: 10.1002/ptr.3073] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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45
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Kodan A, Shibata H, Matsumoto T, Terakado K, Sakiyama K, Matsuo M, Ueda K, Kato H. Improved expression and purification of human multidrug resistance protein MDR1 from baculovirus-infected insect cells. Protein Expr Purif 2009; 66:7-14. [DOI: 10.1016/j.pep.2009.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 02/10/2009] [Accepted: 02/10/2009] [Indexed: 11/25/2022]
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46
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Cannon RD, Lamping E, Holmes AR, Niimi K, Baret PV, Keniya MV, Tanabe K, Niimi M, Goffeau A, Monk BC. Efflux-mediated antifungal drug resistance. Clin Microbiol Rev 2009; 22:291-321, Table of Contents. [PMID: 19366916 PMCID: PMC2668233 DOI: 10.1128/cmr.00051-08] [Citation(s) in RCA: 385] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fungi cause serious infections in the immunocompromised and debilitated, and the incidence of invasive mycoses has increased significantly over the last 3 decades. Slow diagnosis and the relatively few classes of antifungal drugs result in high attributable mortality for systemic fungal infections. Azole antifungals are commonly used for fungal infections, but azole resistance can be a problem for some patient groups. High-level, clinically significant azole resistance usually involves overexpression of plasma membrane efflux pumps belonging to the ATP-binding cassette (ABC) or the major facilitator superfamily class of transporters. The heterologous expression of efflux pumps in model systems, such Saccharomyces cerevisiae, has enabled the functional analysis of efflux pumps from a variety of fungi. Phylogenetic analysis of the ABC pleiotropic drug resistance family has provided a new view of the evolution of this important class of efflux pumps. There are several ways in which the clinical significance of efflux-mediated antifungal drug resistance can be mitigated. Alternative antifungal drugs, such as the echinocandins, that are not efflux pump substrates provide one option. Potential therapeutic approaches that could overcome azole resistance include targeting efflux pump transcriptional regulators and fungal stress response pathways, blockade of energy supply, and direct inhibition of efflux pumps.
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Affiliation(s)
- Richard D Cannon
- Department of Oral Sciences, School of Dentistry, University of Otago, P.O. Box 647, Dunedin 9054, New Zealand.
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47
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Fung KL, Gottesman MM. A synonymous polymorphism in a common MDR1 (ABCB1) haplotype shapes protein function. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1794:860-71. [PMID: 19285158 DOI: 10.1016/j.bbapap.2009.02.014] [Citation(s) in RCA: 248] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 02/23/2009] [Accepted: 02/26/2009] [Indexed: 12/30/2022]
Abstract
The MDR1 (ABCB1) gene encodes a membrane-bound transporter that actively effluxes a wide range of compounds from cells. The overexpression of MDR1 by multidrug-resistant cancer cells is a serious impediment to chemotherapy. MDR1 is expressed in various tissues to protect them from the adverse effect of toxins. The pharmacokinetics of drugs that are also MDR1 substrates also influence disease outcome and treatment efficacy. Although MDR1 is a well-conserved gene, there is increasing evidence that its polymorphisms affect substrate specificity. Three single nucleotide polymorphisms (SNPs) occur frequently and have strong linkage, creating a common haplotype at positions 1236C>T (G412G), 2677G>T (A893S) and 3435C>T (I1145I). The frequency of the synonymous 3435C>T polymorphism has been shown to vary significantly according to ethnicity. Existing literature suggests that the haplotype plays a role in response to drugs and disease susceptibility. This review summarizes recent findings on the 3435C>T polymorphism of MDR1 and the haplotype to which it belongs. A possible molecular mechanism of action by ribosome stalling that can change protein structure and function by altering protein folding is discussed.
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Affiliation(s)
- King Leung Fung
- Laboratory of Cell Biology, Center of Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Drive, Room 2108, Bethesda, MD 20892-4254, USA
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Dai CL, Tiwari AK, Wu CP, Su XD, Wang SR, Liu DG, Ashby CR, Huang Y, Robey RW, Liang YJ, Chen LM, Shi CJ, Ambudkar SV, Chen ZS, Fu LW. Lapatinib (Tykerb, GW572016) reverses multidrug resistance in cancer cells by inhibiting the activity of ATP-binding cassette subfamily B member 1 and G member 2. Cancer Res 2008; 68:7905-14. [PMID: 18829547 DOI: 10.1158/0008-5472.can-08-0499] [Citation(s) in RCA: 321] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Lapatinib is active at the ATP-binding site of tyrosine kinases that are associated with the human epidermal growth factor receptor (Her-1 or ErbB1) and Her-2. It is conceivable that lapatinib may inhibit the function of ATP-binding cassette (ABC) transporters by binding to their ATP-binding sites. The aim of this study was to investigate the ability of lapatinib to reverse tumor multidrug resistance (MDR) due to overexpression of ABC subfamily B member 1 (ABCB1) and ABC subfamily G member 2 (ABCG2) transporters. Our results showed that lapatinib significantly enhanced the sensitivity to ABCB1 or ABCG2 substrates in cells expressing these transporters, although a small synergetic effect was observed in combining lapatinib and conventional chemotherapeutic agents in parental sensitive MCF-7 or S1 cells. Lapatinib alone, however, did not significantly alter the sensitivity of non-ABCB1 or non-ABCG2 substrates in sensitive and resistant cells. Additionally, lapatinib significantly increased the accumulation of doxorubicin or mitoxantrone in ABCB1- or ABCG2-overexpressing cells and inhibited the transport of methotrexate and E(2)17betaG by ABCG2. Furthermore, lapatinib stimulated the ATPase activity of both ABCB1 and ABCG2 and inhibited the photolabeling of ABCB1 or ABCG2 with [(125)I]iodoarylazidoprazosin in a concentration-dependent manner. However, lapatinib did not affect the expression of these transporters at mRNA or protein levels. Importantly, lapatinib also strongly enhanced the effect of paclitaxel on the inhibition of growth of the ABCB1-overexpressing KBv200 cell xenografts in nude mice. Overall, we conclude that lapatinib reverses ABCB1- and ABCG2-mediated MDR by directly inhibiting their transport function. These findings may be useful for cancer combinational therapy with lapatinib in the clinic.
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Affiliation(s)
- Chun-ling Dai
- State Key Laboratory for Oncology in South China, Cancer Center, Sun Yat-Sen University, Guangzhou, China
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Shi Z, Tiwari AK, Shukla S, Robey RW, Kim IW, Parmar S, Bates SE, Si QS, Goldblatt CS, Abraham I, Fu LW, Ambudkar SV, Chen ZS. Inhibiting the function of ABCB1 and ABCG2 by the EGFR tyrosine kinase inhibitor AG1478. Biochem Pharmacol 2008; 77:781-93. [PMID: 19059384 DOI: 10.1016/j.bcp.2008.11.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 11/07/2008] [Accepted: 11/10/2008] [Indexed: 10/21/2022]
Abstract
The tyrphostin 4-(3-chloroanilino)-6,7-dimethoxyquinazoline (AG1478) is a potent and specific EGFR tyrosine kinase inhibitor (TKI); its promising pre-clinical results have led to clinical trials. Overexpression of ATP-binding cassette (ABC) transporters such as ABCB1, ABCC1 and ABCG2 is one of the main causes of multidrug resistance (MDR) and usually results in the failure of cancer chemotherapy. However, the interaction of AG1478 with these ABC transporters is still unclear. In the present study, we have investigated this interaction and found that AG1478 has differential effects on these transporters. In ABCB1-overexpressing cells, non-toxic doses of AG1478 were found to partially inhibit resistance to ABCB1 substrate anticancer drugs as well as increase intracellular accumulation of [3H]-paclitaxel. Similarly, in ABCG2-overexpressing cells, AG1478 significantly reversed resistance to ABCG2 substrate anticancer drugs and increased intracellular accumulation of [3H]-mitoxantrone as well as fluorescent compound BODIPY-prazosin. AG1478 also profoundly inhibited the transport of [3H]-E(2)17betaG and [3H]-methotrexate by ABCG2. We also found that AG1478 slightly stimulated ABCB1 ATPase activity and significantly stimulated ABCG2 ATPase activity. Interestingly, AG1478 did not inhibit the photolabeling of ABCB1 or ABCG2 with [125I]-iodoarylazidoprazosin. Additionally, AG1478 did not alter the sensitivity of parental, ABCB1- or ABCG2-overexpressing cells to non-ABCB1 and non-ABCG2 substrate drug and had no effect on the function of ABCC1. Overall, we conclude that AG1478 is able to inhibit the function of ABCB1 and ABCG2, with a more pronounced effect on ABCG2. Our findings provide valuable contributions to the development of safer and more effective EGFR TKIs for use as anticancer agents in the clinic.
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Affiliation(s)
- Zhi Shi
- Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John's University, Jamaica, NY 11439, USA
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50
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Äänismaa P, Gatlik-Landwojtowicz E, Seelig A. P-Glycoprotein Senses Its Substrates and the Lateral Membrane Packing Density: Consequences for the Catalytic Cycle. Biochemistry 2008; 47:10197-207. [DOI: 10.1021/bi800209h] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Päivi Äänismaa
- Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 70, Basel CH-4056, Switzerland
| | - Ewa Gatlik-Landwojtowicz
- Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 70, Basel CH-4056, Switzerland
| | - Anna Seelig
- Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 70, Basel CH-4056, Switzerland
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