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Characterization of new, efficient Mycobacterium tuberculosis topoisomerase-I inhibitors and their interaction with human ABC multidrug transporters. PLoS One 2018; 13:e0202749. [PMID: 30183750 PMCID: PMC6124754 DOI: 10.1371/journal.pone.0202749] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 08/08/2018] [Indexed: 12/22/2022] Open
Abstract
Drug resistant tuberculosis (TB) is a major worldwide health problem. In addition to the bacterial mechanisms, human drug transporters limiting the cellular accumulation and the pharmacological disposition of drugs also influence the efficacy of treatment. Mycobacterium tuberculosis topoisomerase-I (MtTopo-I) is a promising target for antimicrobial treatment. In our previous work we have identified several hit compounds targeting the MtTopo-I by in silico docking. Here we expand the scope of the compounds around three scaffolds associated with potent MtTopo-I inhibition. In addition to measuring the effect of newly generated compounds on MtTopo-I activity, we characterized the compounds’ antimicrobial activity, toxicity in human cells, and interactions with human multidrug transporters. Some of the newly developed MtTopo-I inhibitors have strong antimicrobial activity and do not harm mammalian cells. Moreover, our studies revealed significant human ABC drug transporter interactions for several MtTopo-I compounds that may modify their ADME-Tox parameters and cellular effects. Promising new drug candidates may be selected based on these studies for further anti-TB drug development.
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52
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Krapf MK, Gallus J, Namasivayam V, Wiese M. 2,4,6-Substituted Quinazolines with Extraordinary Inhibitory Potency toward ABCG2. J Med Chem 2018; 61:7952-7976. [PMID: 30075623 DOI: 10.1021/acs.jmedchem.8b01011] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Several members of the ABC transporter superfamily play a decisive role in the development of multidrug resistance (MDR) in cancer. One of these MDR associated efflux transporters is ABCG2. One way to overcome this MDR is the coadministration of potent inhibitors of ABCG2. In this study, we identified novel inhibitors containing a 2,4,6-substituted quinazoline scaffold. Introduction of a 6-nitro function led to extraordinarily potent compounds that were highly selective for ABCG2 and also able to reverse the MDR toward the chemotherapeutic drugs SN-38 and mitoxantrone. The binding of substrate Hoechst 33342 and the two potent inhibitors 31 and 41 which differ in their mechanism of inhibition was rationalized using the recently published cryo-EM structures of ABCG2. For a better understanding of the interaction between the inhibitors and ABCG2, additional investigations regarding the ATPase activity, the interaction with Hoechst 33342, and with the conformational sensitive 5D3 antibody were carried out.
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Affiliation(s)
- Michael K Krapf
- Pharmaceutical Institute University of Bonn An der Immenburg 4 53121 Bonn , Germany
| | - Jennifer Gallus
- Pharmaceutical Institute University of Bonn An der Immenburg 4 53121 Bonn , Germany
| | | | - Michael Wiese
- Pharmaceutical Institute University of Bonn An der Immenburg 4 53121 Bonn , Germany
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53
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Dail MB, Meek EC, Chambers HW, Chambers JE. In vitro P-glycoprotein activity does not completely explain in vivo efficacy of novel centrally effective oxime acetylcholinesterase reactivators. Drug Chem Toxicol 2018; 42:403-408. [PMID: 29722548 DOI: 10.1080/01480545.2018.1461902] [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] [Indexed: 12/17/2022]
Abstract
Novel-substituted phenoxyalkyl pyridinium oxime acetylcholinesterase (AChE) reactivators (US patent 9,227,937) that showed convincing evidence of penetration into the brains of intact rats were developed by our laboratories. The oximes separated into three groups based on their levels of brain AChE reactivation following exposure of rats to the sarin surrogate nitrophenyl isopropyl methylphosphonate (NIMP). P-glycoprotein (P-gp) is a major blood-brain barrier (BBB) transporter and requires ATP for efflux. To determine if P-gp affinity screening could be used to reduce animal use, we measured in vitro oxime-stimulated ATPase activity to see if the in vivo reactivation efficacies related to the oximes' functions as P-gp substrates. High efficacy oximes were expected to be poor P-gp substrates, thus remaining in the brain longer. The high efficacy oximes (24-35% brain AChE reactivation) were worse P-gp substrates than the low efficacy oximes (0-7% brain AChE reactivation). However, the oxime group with medium in vivo reactivation of 10-17% were even worse P-gp substrates than the high efficacy group so their reactivation ability was not reflected by P-gp export. The results suggest that in vitro P-gp ATPase activity can remove the low efficacy oximes from in vivo testing, but is not sufficient to differentiate between the top two tiers.
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Affiliation(s)
- Mary Beth Dail
- a Center for Environmental Health Sciences, Department of Basic Sciences , College of Veterinary Medicine, Mississippi State University, Mississippi State , MS , USA
| | - Edward Caldwell Meek
- a Center for Environmental Health Sciences, Department of Basic Sciences , College of Veterinary Medicine, Mississippi State University, Mississippi State , MS , USA
| | - Howard Wayne Chambers
- b Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology , Entomology Unit, Mississippi State University, Mississippi State , MS , USA
| | - Janice Elaine Chambers
- a Center for Environmental Health Sciences, Department of Basic Sciences , College of Veterinary Medicine, Mississippi State University, Mississippi State , MS , USA
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54
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Krapf MK, Gallus J, Vahdati S, Wiese M. New Inhibitors of Breast Cancer Resistance Protein (ABCG2) Containing a 2,4-Disubstituted Pyridopyrimidine Scaffold. J Med Chem 2018; 61:3389-3408. [PMID: 29547272 DOI: 10.1021/acs.jmedchem.7b01012] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Multidrug resistance (MDR) occurring during cancer chemotherapy is a major obstacle for effectiveness and response to therapy and is often caused by ATP-binding cassette (ABC) efflux transporters. Belonging to the family of ABC transporters, breast cancer resistance protein is getting more and more in the spotlight of research. As a strategy to overcome MDR, inhibitors of ABC transporters were synthesized, which could be applied in combination with cytostatic drugs. For this purpose, 2,4-disubstituted pyridopyrimidine derivatives were synthesized. The investigations confirmed three key characteristics of good inhibitors: a low intrinsic cytotoxicity and a high potency and selectivity toward ABCG2. For selected compounds the interaction with ABCG2 was elucidated and their effect on ATPase activity and conformation sensitive 5D3 antibody binding was investigated. Their ability to reverse MDR in coadministration with the active metabolite of irinotecan and mitoxantron was confirmed.
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Affiliation(s)
- Michael K Krapf
- Pharmaceutical Institute , University of Bonn , An der Immenburg 4 , 53121 Bonn , Germany
| | - Jennifer Gallus
- Pharmaceutical Institute , University of Bonn , An der Immenburg 4 , 53121 Bonn , Germany
| | - Sahel Vahdati
- Pharmaceutical Institute , University of Bonn , An der Immenburg 4 , 53121 Bonn , Germany
| | - Michael Wiese
- Pharmaceutical Institute , University of Bonn , An der Immenburg 4 , 53121 Bonn , Germany
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55
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Differential effects of histone deacetylase inhibitors on cellular drug transporters and their implications for using epigenetic modifiers in combination chemotherapy. Oncotarget 2018; 7:63829-63838. [PMID: 27564097 PMCID: PMC5325407 DOI: 10.18632/oncotarget.11561] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 08/11/2016] [Indexed: 02/02/2023] Open
Abstract
HDAC inhibitors, DNA alkylators and nucleoside analogs are effective components of combination chemotherapy. To determine a possible mechanism of their synergism, we analyzed the effects of HDAC inhibitors on the expression of drug transporters which export DNA alkylators. Exposure of PEER lymphoma T-cells to 15 nM romidepsin (Rom) resulted in 40%-50% reduction in mRNA for the drug transporter MRP1 and up to ~500-fold increase in the MDR1 mRNA within 32-48 hrs. MRP1 protein levels concomitantly decreased while MDR1 increased. Other HDAC inhibitors - panobinostat, belinostat and suberoylanilide hydroxamic acid (SAHA) - had similar effects on these transporters. The protein level of MRP1 correlated with cellular resistance to busulfan and chlorambucil, and Rom exposure sensitized cells to these DNA alkylators. The decrease in MRP1 correlated with decreased cellular drug export activity, and increased level of MDR1 correlated with increased export of daunorubicin. A similar decrease in the level of MRP1 protein, and increase in MDR1, were observed when mononuclear cells derived from patients with T-cell malignancies were exposed to Rom. Decreased MRP1 and increased MDR1 expressions were also observed in blood mononuclear cells from lymphoma patients who received SAHA-containing chemotherapy in a clinical trial. This inhibitory effect of HDAC inhibitors on the expression of MRP1 suggests that their synergism with DNA alkylating agents is partly due to decreased efflux of these alkylators. Our results further imply the possibility of antagonistic effects when HDAC inhibitors are combined with anthracyclines and other MDR1 drug ligands in chemotherapy.
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56
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David M, Lebrun C, Duguet T, Talmont F, Beech R, Orlowski S, André F, Prichard RK, Lespine A. Structural model, functional modulation by ivermectin and tissue localization of Haemonchus contortus P-glycoprotein-13. Int J Parasitol Drugs Drug Resist 2018; 8:145-157. [PMID: 29571165 PMCID: PMC6114108 DOI: 10.1016/j.ijpddr.2018.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 02/09/2018] [Accepted: 02/12/2018] [Indexed: 12/18/2022]
Abstract
Haemonchus contortus, one of the most economically important parasites of small ruminants, has become resistant to the anthelmintic ivermectin. Deciphering the role of P-glycoproteins in ivermectin resistance is desirable for understanding and overcoming this resistance. In the model nematode, Caenorhabditis elegans, P-glycoprotein-13 is expressed in the amphids, important neuronal structures for ivermectin activity. We have focused on its ortholog in the parasite, Hco-Pgp-13. A 3D model of Hco-Pgp-13, presenting an open inward-facing conformation, has been constructed by homology with the Cel-Pgp-1 crystal structure. In silico docking calculations predicted high affinity binding of ivermectin and actinomycin D to the inner chamber of the protein. Following in vitro expression, we showed that ivermectin and actinomycin D modulated Hco-Pgp-13 ATPase activity with high affinity. Finally, we found in vivo Hco-Pgp-13 localization in epithelial, pharyngeal and neuronal tissues. Taken together, these data suggest a role for Hco-Pgp-13 in ivermectin transport, which could contribute to anthelmintic resistance.
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Affiliation(s)
- Marion David
- INTHERES, Université de Toulouse, INRA, ENVT, Toulouse, France; Institute of Parasitology, McGill University, Sainte-Anne-De-Bellevue, Canada
| | - Chantal Lebrun
- INTHERES, Université de Toulouse, INRA, ENVT, Toulouse, France
| | - Thomas Duguet
- Institute of Parasitology, McGill University, Sainte-Anne-De-Bellevue, Canada
| | - Franck Talmont
- Institute of Pharmacology and Structural Biology, UMR 5089, CNRS, Toulouse, France
| | - Robin Beech
- Institute of Parasitology, McGill University, Sainte-Anne-De-Bellevue, Canada
| | - Stéphane Orlowski
- CEA, Institut de Biologie Frédéric Joliot, Centre de Saclay, SB2SM, UMR9198 CNRS, I2BC; 91191 Gif-sur-Yvette Cedex, France
| | - François André
- CEA, Institut de Biologie Frédéric Joliot, Centre de Saclay, SB2SM, UMR9198 CNRS, I2BC; 91191 Gif-sur-Yvette Cedex, France
| | - Roger K Prichard
- Institute of Parasitology, McGill University, Sainte-Anne-De-Bellevue, Canada.
| | - Anne Lespine
- INTHERES, Université de Toulouse, INRA, ENVT, Toulouse, France.
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57
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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: 313] [Impact Index Per Article: 52.2] [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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58
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Karasik A, Ledwitch KV, Arányi T, Váradi A, Roberts A, Szeri F. Boosted coupling of ATP hydrolysis to substrate transport upon cooperative estradiol-17-β-D-glucuronide binding in a Drosophila ATP binding cassette type-C transporter. FASEB J 2018; 32:669-680. [PMID: 28939593 DOI: 10.1096/fj.201700606r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
ATP binding cassette type-C (ABCC) transporters move molecules across cell membranes upon hydrolysis of ATP; however, their coupling of ATP hydrolysis to substrate transport remains elusive. Drosophila multidrug resistance-associated protein (DMRP) is the functional ortholog of human long ABCC transporters, with similar substrate and inhibitor specificity, but higher activity. Exploiting its high activity, we kinetically dissected the catalytic mechanism of DMRP by using E2-d-glucuronide (E2G), the physiologic substrate of human ABCC. We examined the DMRP-mediated interdependence of ATP and E2G in biochemical assays. We observed E2G-dependent ATPase activity to be biphasic at subsaturating ATP concentrations, which implies at least 2 E2G binding sites on DMRP. Furthermore, transport measurements indicated strong nonreciprocal cooperativity between ATP and E2G. In addition to confirming these findings, our kinetic modeling with the Complex Pathway Simulator indicated a 10-fold decrease in the E2G-mediated activation of ATP hydrolysis upon saturation of the second E2G binding site. Surprisingly, the binding of the second E2G allowed for substrate transport with a constant rate, which tightly coupled ATP hydrolysis to transport. In summary, we show that the second E2G binding-similar to human ABCC2-allosterically stimulates transport activity of DMRP. Our data suggest that this is achieved by a significant increase in the coupling of ATP hydrolysis to transport.-Karasik, A., Ledwitch, K. V., Arányi, T., Váradi, A., Roberts, A., Szeri, F. Boosted coupling of ATP hydrolysis to substrate transport upon cooperative estradiol-17-β-D-glucuronide binding in a Drosophila ATP binding cassette type-C transporter.
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Affiliation(s)
- Agnes Karasik
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | | | - Tamás Arányi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - András Váradi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Arthur Roberts
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia, USA
| | - Flóra Szeri
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
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59
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Morsy MA, El-Sheikh AAK, Ibrahim ARN, Khedr MA, Al-Taher AY. In silico comparisons between natural inhibitors of ABCB1/P-glycoprotein to overcome doxorubicin-resistance in the NCI/ADR-RES cell line. Eur J Pharm Sci 2017; 112:87-94. [PMID: 29133241 DOI: 10.1016/j.ejps.2017.11.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 11/06/2017] [Accepted: 11/09/2017] [Indexed: 12/23/2022]
Abstract
To investigate compound-protein binding mode and molecular dynamic simulation of P-glycoprotein (P-gp), in silico studies were performed to compare 12 naturally occurring compounds using two softwares. The net results showed that piperine (PIP) had the best binding affinity. In vitro studies on doxorubicin (DOX)-resistant NCI/ADR-RES cells, known to express P-gp, showed that, dose-dependently, PIP significantly increased intracellular accumulation of rhodamine-123 and had cytotoxic effects accessed by MTT assay. In addition, PIP at 25 and 50μM significantly potentiated DOX-induced cytotoxicity on the same cell line. P-gp ATPase assay showed that both DOX and PIP had dose-dependent inhibition of orthovandate-sensitive ATPase activity, indicating they are both P-gp inhibitors, with IC50 of 84±1 and 37±2μM, respectively. PIP did not show any activation of ATPase activity, while DOX did, indicating that P-gp does not accept PIP as a substrate. Using DOX at concentration 33.33μM together with PIP (100μM), DOX-mediated P-gp ATPase activity was decreased to levels 4-folds lower than DOX alone. In conclusion, both in silico and in vitro studies confirm that PIP is an inhibitor of P-gp mediated DOX efflux, suggesting PIP as a promising adjuvant to DOX cancer chemotherapy.
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Affiliation(s)
- Mohamed A Morsy
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, 31982 Al-Ahsa, Saudi Arabia; Department of Pharmacology, Faculty of Medicine, Minia University, 61511 El-Minia, Egypt.
| | - Azza A K El-Sheikh
- Department of Pharmacology, Faculty of Medicine, Minia University, 61511 El-Minia, Egypt; Basic Health Sciences Department, Faculty of Medicine, Princess Nourah bint Abdulrahman University, 11671 Riyadh, Saudi Arabia
| | - Ahmed R N Ibrahim
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, 31982 Al-Ahsa, Saudi Arabia; Department of Biochemistry, Faculty of Pharmacy, Minia University, 61511 El-Minia, Egypt
| | - Mohammed A Khedr
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, 31982 Al-Ahsa, Saudi Arabia; Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Helwan University, 11795 Cairo, Egypt
| | - Abdulla Y Al-Taher
- Department of Physiology, Biochemistry and Pharmacology, College of Veterinary Medicine, King Faisal University, 31982 Al-Ahsa, Saudi Arabia
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60
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Khunweeraphong N, Stockner T, Kuchler K. The structure of the human ABC transporter ABCG2 reveals a novel mechanism for drug extrusion. Sci Rep 2017; 7:13767. [PMID: 29061978 PMCID: PMC5653816 DOI: 10.1038/s41598-017-11794-w] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 08/31/2017] [Indexed: 12/13/2022] Open
Abstract
The human ABC transporter ABCG2 (Breast Cancer Resistance Protein, BCRP) is implicated in anticancer resistance, in detoxification across barriers and linked to gout. Here, we generate a novel atomic model of ABCG2 using the crystal structure of ABCG5/G8. Extensive mutagenesis verifies the structure, disclosing hitherto unrecognized essential residues and domains in the homodimeric ABCG2 transporter. The elbow helix, the first intracellular loop (ICL1) and the nucleotide-binding domain (NBD) constitute pivotal elements of the architecture building the transmission interface that borders a central cavity which acts as a drug trap. The transmission interface is stabilized by salt-bridge interactions between the elbow helix and ICL1, as well as within ICL1, which is essential to control the conformational switch of ABCG2 to the outward-open drug-releasing conformation. Importantly, we propose that ICL1 operates like a molecular spring that holds the NBD dimer close to the membrane, thereby enabling efficient coupling of ATP hydrolysis during the catalytic cycle. These novel mechanistic data open new opportunities to therapeutically target ABCG2 in the context of related diseases.
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Affiliation(s)
- Narakorn Khunweeraphong
- Center for Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, Campus Vienna Biocenter, Dr. Bohr-Gasse 9/2, A-1030, Vienna, Austria
| | - Thomas Stockner
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Währingerstrasse 13A, A-1090, Vienna, Austria
| | - Karl Kuchler
- Center for Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, Campus Vienna Biocenter, Dr. Bohr-Gasse 9/2, A-1030, Vienna, Austria.
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61
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Zatloukalová M, Nazaruk E, Novák D, Vacek J, Bilewicz R. Lipidic liquid crystalline cubic phases for preparation of ATP-hydrolysing enzyme electrodes. Biosens Bioelectron 2017; 100:437-444. [PMID: 28961546 DOI: 10.1016/j.bios.2017.09.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 09/17/2017] [Accepted: 09/18/2017] [Indexed: 11/26/2022]
Abstract
The lipidic liquid-crystalline cubic phase (LCP) is a membrane-mimetic material useful for the stabilization and structural analysis of membrane proteins. Here, we focused on the incorporation of the membrane ATP-hydrolysing sodium/potassium transporter Na+/K+-ATPase (NKA) into a monoolein-derived LCP. Small-angle X-ray scattering was employed for the determination of the LCP structure, which was of Pn3m symmetry for all the formulations studied. The fully characterized NKA-LCP material was immobilized onto a glassy carbon electrode, forming a highly stable enzyme electrode and a novel sensing platform. A typical NKA voltammetric signature was monitored via the anodic reaction of tyrosine and tryptophan residues. The in situ enzyme activity evaluation was based on the ability of NKA to transform ATP to ADP and free phosphate, the latter reacting with ammonium molybdate to form the ammonium phosphomolybdate complex under acidic conditions. The square-wave voltammetric detection of phosphomolybdate was performed and complemented with spectrophotometric measurement at 710nm. The anodic voltammetric response, corresponding to the catalytic ATP-hydrolysing function of NKA incorporated into the LCP, was monitored at around + 0.2V vs. Ag/AgCl in the presence or absence of ouabain, a specific NKA inhibitor. NKA incorporated into the LCP retained its ATP-hydrolysing activity for 7 days, while the solubilized protein became practically inactive. The novelty of this work is the first incorporation of NKA into a lipidic cubic phase with consequent enzyme functionality and stability evaluation using voltammetric detection. The application of LCPs could also be important in the further development of new membrane protein electrochemical sensors and enzyme electrodes.
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Affiliation(s)
- Martina Zatloukalová
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland; Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 3, 775 15 Olomouc, Czech Republic
| | - Ewa Nazaruk
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - David Novák
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 3, 775 15 Olomouc, Czech Republic
| | - Jan Vacek
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 3, 775 15 Olomouc, Czech Republic.
| | - Renata Bilewicz
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
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62
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Wagmann L, Maurer HH, Meyer MR. An easy and fast adenosine 5'-diphosphate quantification procedure based on hydrophilic interaction liquid chromatography-high resolution tandem mass spectrometry for determination of the in vitro adenosine 5'-triphosphatase activity of the human breast cancer resistance protein ABCG2. J Chromatogr A 2017; 1521:123-130. [PMID: 28951049 DOI: 10.1016/j.chroma.2017.09.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 09/01/2017] [Accepted: 09/15/2017] [Indexed: 11/30/2022]
Abstract
Interactions with the human breast cancer resistance protein (hBCRP) significantly influence the pharmacokinetic properties of a drug and can even lead to drug-drug interactions. As efflux pump from the ABC superfamily, hBCRP utilized energy gained by adenosine 5'-triphosphate (ATP) hydrolysis for the transmembrane movement of its substrates, while adenosine 5'-diphosphate (ADP) and inorganic phosphate were released. The ADP liberation can be used to detect interactions with the hBCRP ATPase. An ADP quantification method based on hydrophilic interaction liquid chromatography (HILIC) coupled to high resolution tandem mass spectrometry (HR-MS/MS) was developed and successfully validated in accordance to the criteria of the guideline on bioanalytical method validation by the European Medicines Agency. ATP and adenosine 5'-monophosphate were qualitatively included to prevent interferences. Furthermore, a setup consisting of six sample sets was evolved that allowed detection of hBCRP substrate or inhibitor properties of the test compound. The hBCRP substrate sulfasalazine and the hBCRP inhibitor orthovanadate were used as controls. To prove the applicability of the procedure, the effect of amprenavir, indinavir, nelfinavir, ritonavir, and saquinavir on the hBCRP ATPase activity was tested. Nelfinavir, ritonavir, and saquinavir were identified as hBCRP ATPase inhibitors and none of the five HIV protease inhibitors turned out to be an hBCRP substrate. These findings were in line with a pervious publication.
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Affiliation(s)
- Lea Wagmann
- Department of Experimental and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Saarland University, D-66421 Homburg, Saar, Germany
| | - Hans H Maurer
- Department of Experimental and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Saarland University, D-66421 Homburg, Saar, Germany
| | - Markus R Meyer
- Department of Experimental and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Saarland University, D-66421 Homburg, Saar, Germany.
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63
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Loo TW, Clarke DM. A short cross-linker activates human P-glycoprotein missing a catalytic carboxylate. Biochem Pharmacol 2017; 145:27-33. [PMID: 28837794 DOI: 10.1016/j.bcp.2017.08.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 08/18/2017] [Indexed: 11/17/2022]
Abstract
P-glycoprotein (P-gp) is an ATP-dependent drug pump that protects us from toxic agents and confers multidrug resistance. It has a tweezer-like structure with each arm consisting of a transmembrane domain (TMD) and a nucleotide-binding domain (NBD). Drug substrates bind to sites within the TMDs to activate ATPase activity by promoting a tweezer-like closing of the gap between the NBDs. The catalytic carboxylates may be critical for NBD movements because the E556Q(NBD1) or E1201Q(NBD2) mutation inhibited drug-stimulated ATPase activity. If the catalytic carboxylates were components of the mechanism to bring the NBDs together, then we predicted that insertion of a flexible cross-linker between the arms would increase ATPase activity of the mutants. We found that cross-linking (between L175C(TMD1) and N820C(TMD2)) with a short flexible cross-linker (7.8Å maximum) restored high levels of drug-stimulated ATPase activity of the E556Q or E1201Q mutants. Cross-linking with a longer cross-linker (22Å maximum) however, did not restore activity. Cross-linking could not rescue all ATPase deficient mutants. For example, cross-linking L175C/N820C with short or long cross-linkers did not activate the H-loop mutants H587A or H1232A or the Walker A K433M or K1076M mutants. The results suggest that the E556 and E1201 catalytic carboxylates are part of a spring-like mechanism that is required to facilitate movements between the open and closed conformations of P-gp during ATP hydrolysis.
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Affiliation(s)
- Tip W Loo
- Department of Medicine and Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - David M Clarke
- Department of Medicine and Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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Synthesis and biological investigation of 2,4-substituted quinazolines as highly potent inhibitors of breast cancer resistance protein (ABCG2). Eur J Med Chem 2017; 139:587-611. [PMID: 28841513 DOI: 10.1016/j.ejmech.2017.08.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/25/2017] [Accepted: 08/07/2017] [Indexed: 11/23/2022]
Abstract
Expression of ABCG2, a member of the ABC transporter superfamily, has been correlated to the clinical outcome of multiple cancers and is often associated with the occurrence of multidrug resistance (MDR) in chemotherapy. Inhibition of the transport protein by potent and selective inhibitors might be a way to treat cancer more efficiently and improve the therapy of cancer patients. Recently we reported the synthesis of new inhibitors based on a quinazoline scaffold. In the present study more structural variations were explored. Compounds with 3,4-dimethoxy groups and meta or para nitro substituents were found to be highly potent inhibitors of ABCG2. The most potent compound was more than five-fold more potent than Ko143, one of the best inhibitors of ABCG2. To determine the new compounds selectivity toward ABCG2 their inhibitory effects on ABCB1 and ABCC1 were also investigated identifying selective as well as broadspectrum inhibitors. Furthermore, intrinsic cytotoxicity and efficacy regarding the reversal of multidrug resistance toward SN-38 and mitoxantrone were explored. The most potent compounds were able to reverse the resistance toward the cytostatic agents with EC50 values below 20 nM. Additionally, the type of interaction between inhibitors and the ABCG2 substrate Hoechst 33342 was investigated yielding competitive and non-competitive interactions suggesting different modes of binding. Finally the effect of the derivatives on vanadate-sensitive ATPase activity of ABCG2 was determined. According to the different effects on ATPase activity we conclude the existence of different binding sites. This study provides the structural requirements for high potency inhibition and elucidates the interaction with ABCG2 setting the basis for further studies.
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65
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Loo TW, Clarke DM. Thiol-reactive drug substrates of human P-glycoprotein label the same sites to activate ATPase activity in membranes or dodecyl maltoside detergent micelles. Biochem Biophys Res Commun 2017; 488:573-577. [DOI: 10.1016/j.bbrc.2017.05.106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 05/19/2017] [Indexed: 12/31/2022]
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66
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Krapf MK, Gallus J, Wiese M. 4-Anilino-2-pyridylquinazolines and -pyrimidines as Highly Potent and Nontoxic Inhibitors of Breast Cancer Resistance Protein (ABCG2). J Med Chem 2017; 60:4474-4495. [PMID: 28471656 DOI: 10.1021/acs.jmedchem.7b00441] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Multidrug resistance (MDR) mediated by ATP-binding cassette (ABC) transport proteins remains a major problem in the chemotherapeutic treatment of cancer and might be overcome by inhibition of the transporter. Because of the lack of understanding, the complex mechanisms involved in the transport process, in particular for breast cancer resistance protein (BCRP/ABCG2), there is a persistent need for studies of inhibitors of ABCG2. In this study, we investigated a systematic series of 4-substituted-2-pyridylquinazolines in terms of their inhibitory potency as well as selectivity toward ABCG2. For comparison, the quinazoline scaffold was reduced to the significantly smaller 4-methylpyrimidine basic structure. Furthermore, the cytotoxicity and the ability to reverse MDR was tested with the chemotherapeutic agents SN-38 and mitoxantrone (MX). Interaction of the compounds with ABCG2 was investigated by a colorimetric ATPase assay. Enzyme kinetic studies were carried out with Hoechst 33342 as fluorescent dye and substrate of ABCG2 to elucidate the compounds binding modes.
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Affiliation(s)
- Michael K Krapf
- Pharmaceutical Institute, University of Bonn , An der Immenburg 4, 53121 Bonn, Germany
| | - Jennifer Gallus
- Pharmaceutical Institute, University of Bonn , An der Immenburg 4, 53121 Bonn, Germany
| | - Michael Wiese
- Pharmaceutical Institute, University of Bonn , An der Immenburg 4, 53121 Bonn, Germany
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67
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Li MJ, Nath A, Atkins WM. Differential Coupling of Binding, ATP Hydrolysis, and Transport of Fluorescent Probes with P-Glycoprotein in Lipid Nanodiscs. Biochemistry 2017; 56:2506-2517. [PMID: 28441502 DOI: 10.1021/acs.biochem.6b01245] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The ATP binding cassette transporter P-glycoprotein (ABCB1 or P-gp) plays a major role in cellular resistance to drugs and drug interactions. Experimental studies support a mechanism with nucleotide-dependent fluctuation between inward-facing and outward-facing conformations, which are coupled to nucleotide hydrolysis. However, detailed insight into drug-dependent modulation of these conformational ensembles is lacking. Different drugs likely occupy partially overlapping but distinct sites and are therefore variably coupled to nucleotide binding and hydrolysis. Many fluorescent drug analogues are used in cell-based transport models; however, their specific interactions with P-gp have not been studied, and this limits interpretation of transport assays in terms of molecular models. Here we monitor binding of the fluorescent probe substrates BODIPY-verapamil, BODIPY-vinblastine, and Flutax-2 at low occupancy to murine P-gp in lipid nanodiscs via fluorescence correlation spectroscopy, in variable nucleotide-bound states. Changes in affinity for the different nucleotide-dependent conformations are probe-dependent. For BODIPY-verapamil and BODIPY-vinblastine, there are 2-10-fold increases in KD in the nucleotide-bound or vanadate-trapped state, compared to that in the nucleotide-free state. In contrast, the affinity of Flutax-2 is unaffected by nucleotide or vanadate trapping. In further contrast to BODIPY-verapamil and BODIPY-vinblastine, Flutax-2 does not cause stimulation of ATP hydrolysis despite the fact that it is transported in vesicle-based transport assays. Whereas the established substrates verapamil, paclitaxel, and vinblastine displace BODIPY-verapamil or BODIPY-vinblastine from their high-affinity sites, the transport substrate Flutax-2 is not displaced by any of these substrates. The results demonstrate a unique binding site for Flutax-2 that allows for transport without stimulation of ATP hydrolysis.
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Affiliation(s)
- Mavis Jiarong Li
- Department of Medicinal Chemistry, University of Washington , Box 357610, Seattle, Washington 98195-7610, United States
| | - Abhinav Nath
- Department of Medicinal Chemistry, University of Washington , Box 357610, Seattle, Washington 98195-7610, United States
| | - William M Atkins
- Department of Medicinal Chemistry, University of Washington , Box 357610, Seattle, Washington 98195-7610, United States
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68
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Xu Y, Seelig A, Bernèche S. Unidirectional Transport Mechanism in an ATP Dependent Exporter. ACS CENTRAL SCIENCE 2017; 3:250-258. [PMID: 28386603 PMCID: PMC5364450 DOI: 10.1021/acscentsci.7b00068] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Indexed: 05/25/2023]
Abstract
ATP-binding cassette (ABC) transporters use the energy of ATP binding and hydrolysis to move a large variety of compounds across biological membranes. P-glycoprotein, involved in multidrug resistance, is the most investigated eukaryotic family member. Although a large number of biochemical and structural approaches have provided important information, the conformational dynamics underlying the coupling between ATP binding/hydrolysis and allocrite transport remains elusive. To tackle this issue, we performed molecular dynamic simulations for different nucleotide occupancy states of Sav1866, a prokaryotic P-glycoprotein homologue. The simulations reveal an outward-closed conformation of the transmembrane domain that is stabilized by the binding of two ATP molecules. The hydrolysis of a single ATP leads the X-loop, a key motif of the ATP binding cassette, to interfere with the transmembrane domain and favor its outward-open conformation. Our findings provide a structural basis for the unidirectionality of transport in ABC exporters and suggest a ratio of one ATP hydrolyzed per transport cycle.
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Affiliation(s)
- Yanyan Xu
- SIB
Swiss Institute of Bioinformatics, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Anna Seelig
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Simon Bernèche
- SIB
Swiss Institute of Bioinformatics, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
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69
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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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70
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Cunha V, Burkhardt-Medicke K, Wellner P, Santos MM, Moradas-Ferreira P, Luckenbach T, Ferreira M. Effects of pharmaceuticals and personal care products (PPCPs) on multixenobiotic resistance (MXR) related efflux transporter activity in zebrafish (Danio rerio) embryos. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2017; 136:14-23. [PMID: 27810576 DOI: 10.1016/j.ecoenv.2016.10.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 06/06/2023]
Abstract
Certain ATP binding cassette (ABC) transporter proteins, such as zebrafish Abcb4, are efflux pumps acting as a cellular defence against a wide range of different, potentially toxic chemical compounds thus mediating so called multixenobiotic resistance (MXR). Certain chemicals target MXR proteins and, as so called chemosensitisers, inhibit the activity of these proteins thus increasing the toxicity of other chemicals that would normally be effluxed. In this study 14 pharmaceuticals and personal care products (PPCPs) that are being increasingly detected in aquatic systems, were assessed for interference with the MXR system of zebrafish (Danio rerio). Concentration dependent effects of test compounds were recorded with the dye accumulation assay using zebrafish embryos and in ATPase assays with recombinant zebrafish Abcb4. In the dye accumulation assay embryos at 24h post fertilisation (hpf) were exposed to 8µm rhodamine 123 along with test compounds for 2h. The rhodamine 123 tissue levels upon the exposure served as a measure for MXR transporter efflux activity of the embryo (low rhodamine levels - high activity; high levels - low activity). The known ABC protein inhibitors MK571, vinblastine and verapamil served as positive controls. All tested PPCPs affected rhodamine 123 accumulation in embryos. For seven compounds rhodamine tissue levels were either both decreased and increased depending on the compound concentration indicating both stimulation and inhibition of rhodamine 123 efflux by those compounds, only increased (inhibition, six compounds) or only decreased (stimulation, one compound). Recombinant zebrafish Abcb4 was obtained with the baculovirus expression system and PPCPs were tested for stimulation/inhibition of basal transporter ATPase activity and for inhibition of the transporter ATPase activity stimulated with verapamil. Eight of the tested PPCPs showed effects on Abcb4 ATPase activity indicating that their effects in the dye accumulation assay may have indeed resulted from interference with Abcb4-mediated rhodamine 123 efflux. Slight stimulatory effects were found for musk xylene, nerol, isoeugenol, α-amylcinnamaldehyde, α-hexylcinnamaldehyde and simvastatin indicating Abcb4 substrate/competitive inhibitor properties of those compounds. Likewise, decreases of the verapamil-stimulated Abcb4 ATPase activity by diclofenac and fluoxetine may indicate competitive transporter inhibition. Sertraline inhibited the basal and verapamil-stimulated Abcb4 ATPase activities suggesting its property as non-competitive Abcb4 inhibitor. Taken together, our finding that chemically diverse PPCPs interfere with MXR efflux activity of zebrafish indicates that (1) efflux transporters may influence bioaccumulation of many PPCPs in fish and that (2) many PPCPs may act as chemosensitisers. Furthermore, it appears that interference of PPCPs with efflux activity in zebrafish embryos is not only from effects on Abcb4 but also on other efflux transporter subtypes.
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Affiliation(s)
- V Cunha
- CIIMAR/CIMAR-Interdisciplinary Centre of Marine and Environmental Research, Coastal and Marine Environmental Toxicology Lab, University of Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal; ICBAS/UP-Institute of Biomedical Sciences Abel Salazar, University of Porto, Largo Professor Abel Salazar, 2, 4099-003 Porto, Portugal.
| | - K Burkhardt-Medicke
- UFZ-Helmholtz-Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstraße 15, 04318 Leipzig, Germany; Technische Universitaet Dresden, Faculty of Environmental Sciences, Institute of Hydrobiology, 01062 Dresden, Germany
| | - P Wellner
- UFZ-Helmholtz-Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstraße 15, 04318 Leipzig, Germany
| | - M M Santos
- CIIMAR/CIMAR-Interdisciplinary Centre of Marine and Environmental Research, Coastal and Marine Environmental Toxicology Lab, University of Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal; FCUP-Dept of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal; 5IBMC-Institute for Molecular and Cell Biology, University of Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - P Moradas-Ferreira
- ICBAS/UP-Institute of Biomedical Sciences Abel Salazar, University of Porto, Largo Professor Abel Salazar, 2, 4099-003 Porto, Portugal; I3S-Institute for Research and Innovation in Health, University of Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC, Institute for Molecular and Cell Biology, Porto, Portugal
| | - T Luckenbach
- UFZ-Helmholtz-Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstraße 15, 04318 Leipzig, Germany
| | - M Ferreira
- CIIMAR/CIMAR-Interdisciplinary Centre of Marine and Environmental Research, Coastal and Marine Environmental Toxicology Lab, University of Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal; School of Marine Studies, Faculty of Science, Technology and Environment, The University of South Pacific, Laucala Bay Road, Suva, Fiji Islands
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71
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Tarapcsák S, Szalóki G, Telbisz Á, Gyöngy Z, Matúz K, Csősz É, Nagy P, Holb IJ, Rühl R, Nagy L, Szabó G, Goda K. Interactions of retinoids with the ABC transporters P-glycoprotein and Breast Cancer Resistance Protein. Sci Rep 2017; 7:41376. [PMID: 28145501 PMCID: PMC5286421 DOI: 10.1038/srep41376] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 12/20/2016] [Indexed: 01/16/2023] Open
Abstract
Retinoids – derivatives of vitamin A – are important cell permeant signaling molecules that regulate gene expression through activation of nuclear receptors. P-glycoprotein (Pgp) and ABCG2 are plasma membrane efflux transporters affecting the tissue distribution of numerous structurally unrelated lipophilic compounds. In the present work we aimed to study the interaction of the above ABC transporters with retinoid derivatives. We have found that 13-cis-retinoic acid, retinol and retinyl-acetate inhibited the Pgp and ABCG2 mediated substrate transport as well as the substrate stimulated ATPase activity of these transporters. Interestingly, 9-cis-retinoic acid and ATRA (all-trans retinoic acid), both are stereoisomers of 13-cis-retinoic acid, did not have any effect on the transporters’ activity. Our fluorescence anisotropy measurements revealed that 13-cis-retinoic acid, retinol and retinyl-acetate selectively increase the viscosity and packing density of the membrane. Thus, the mixed-type inhibition of both transporters by retinol and ABCG2 by 13-cis-retinoic acid may be the collective result of direct interactions of these retinoids with the substrate binding site(s) and of indirect interactions mediated by their membrane rigidifying effects.
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Affiliation(s)
- Szabolcs Tarapcsák
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Gábor Szalóki
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Ágnes Telbisz
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, H-1117 Magyar tudósok körútja 2, P.O.B. 286, Hungary
| | - Zsuzsanna Gyöngy
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Krisztina Matúz
- Department of Biochemistry and Molecular Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Éva Csősz
- Department of Biochemistry and Molecular Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Péter Nagy
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Imre J Holb
- Institute of Horticulture, University of Debrecen, Debrecen, H-4015 Böszörményi út 138, P.O.B. 400, Hungary.,Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, H-1525 Hermann Ottó út 15, P.O.B. 525, Hungary
| | - Ralph Rühl
- MTA-DE, Public Health Research Group of the Hungarian Academy of Sciences, Faculty of Public Health, University of Debrecen, Debrecen, H-4028 Kassai út 26, P.O.B. 400, Hungary
| | - László Nagy
- Department of Biochemistry and Molecular Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Gábor Szabó
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Katalin Goda
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
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72
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Loo TW, Clarke DM. Attachment of a 'molecular spring' restores drug-stimulated ATPase activity to P-glycoprotein lacking both Q loop glutamines. Biochem Biophys Res Commun 2016; 483:366-370. [PMID: 28025146 DOI: 10.1016/j.bbrc.2016.12.137] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 12/21/2016] [Indexed: 01/28/2023]
Abstract
P-glycoprotein (P-gp) is an ABC (ATP-Binding Cassette) drug pump that is clinically important because it confers multidrug resistance. Drugs bind at the interface between the transmembrane domains to activate ATPase activity at the two nucleotide-binding domains (NBDs). Drug transport involves ATP-dependent conformational changes between inward- (open, NBDs far apart) and outward-facing (closed, NBDs close together) conformations. Recently, it was reported that the conserved glutamines residues (Gln475 in NBD1 and Gln1118 in NBD2) in the Q loops of P-gp when mutated to alanine completely inhibited the drug-stimulated ATPase activity. It is unknown why the glutamine residues (Gln475 and Gln1118) in the Q loops of the NBDs of P-gp are required for drug-stimulated ATPase activity. Here we show that introduction of these mutations into the L175C/N820C mutant (L175C/N820C/Q475A/Q1118A) also abolished drug-stimulated ATPase activity. The ATPase activity was restored however, when the L175C/N820C/Q475A/Q1118A mutant was cross-linked with a flexible disulfide cross-linker. These results suggest that both Q-loop glutamines are not required for ATP hydrolysis and they might function as part of a spring-like mechanism in facilitating the open (inactive) to closed (active) conformational change during ATP hydrolysis. The molecular spring-like action of the Q-loop glutamines during drug-stimulated ATPase activity is likely mimicked by the attachment of the flexible cross-linker.
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Affiliation(s)
- Tip W Loo
- Department of Medicine and Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - David M Clarke
- Department of Medicine and Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
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73
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Zaja R, Popović M, Lončar J, Smital T. Functional characterization of rainbow trout (Oncorhynchus mykiss) Abcg2a (Bcrp) transporter. Comp Biochem Physiol C Toxicol Pharmacol 2016; 190:15-23. [PMID: 27475308 DOI: 10.1016/j.cbpc.2016.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 11/18/2022]
Abstract
ABCG2 (BCRP - breast cancer resistance protein) belongs to the ATP-binding cassette (ABC) superfamily. It plays an important role in the disposition and elimination of xeno- and endobiotics and/or their metabolites in mammals. Likewise, the protective role of ABC transporters, including Abcg2, has been reported for aquatic organisms. In our previous study we have cloned the full gene sequence of rainbow trout (Oncorhynchus mykiss) Abcg2a and showed its high expression in liver and primary hepatocytes. Based on those insights, the main goal of this study was to perform a detailed functional characterization of trout Abcg2a using insect ovary cells (Spodoptera frugiperda, Sf9) as a heterologous expression system. Membrane vesicles preparations from Sf9 cells were used for the ATPase assay determinations and basic biochemical properties of fish Abcg2a versus human ABCG2 have been compared. A series of 39 physiologically and/or environmentally relevant substances was then tested on interaction with trout Abcg2a and human ABCG2. Correlation analysis reveals highly similar pattern of activation and inhibition. Significant activation of trout Abcg2a ATPase was observed for prazosin, doxorubicine, sildenafil, furosemid, propranolol, fenofibrate and pheophorbide. Pesticides showed either a weak activation (malathione) or strong (endosulfan) to weak (chlorpyrifos, fenoxycarb, DDE) inhibition of trout Abcg2a ATPase while the highest activation was obtained for benzo(a)pyrene, curcumine and testosterone. In conclusion, data from this study offer the first characterization of fish Abcg2a, reveal potent interactors among physiologically or environmentally relevant substances and point to similarities regarding strengths and interactor preferences between human ABCG2 and fish Abcg2a.
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Affiliation(s)
- Roko Zaja
- Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia
| | - Marta Popović
- Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia
| | - Jovica Lončar
- Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia
| | - Tvrtko Smital
- Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia.
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74
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Xiao L, Yi T, Chen M, Lam CWK, Zhou H. A new mechanism for increasing the oral bioavailability of scutellarin with Cremophor EL: Activation of MRP3 with concurrent inhibition of MRP2 and BCRP. Eur J Pharm Sci 2016; 93:456-67. [DOI: 10.1016/j.ejps.2016.08.054] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 08/24/2016] [Accepted: 08/28/2016] [Indexed: 01/16/2023]
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75
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Nerada Z, Hegyi Z, Szepesi Á, Tóth S, Hegedüs C, Várady G, Matula Z, Homolya L, Sarkadi B, Telbisz Á. Application of fluorescent dye substrates for functional characterization of ABC multidrug transporters at a single cell level. Cytometry A 2016; 89:826-34. [DOI: 10.1002/cyto.a.22931] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/23/2016] [Accepted: 07/27/2016] [Indexed: 01/08/2023]
Affiliation(s)
- Zsuzsanna Nerada
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences; Budapest Hungary
| | - Zoltán Hegyi
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences; Budapest Hungary
| | - Áron Szepesi
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences; Budapest Hungary
| | - Szilárd Tóth
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences; Budapest Hungary
| | - Csilla Hegedüs
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences; Budapest Hungary
| | - György Várady
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences; Budapest Hungary
| | - Zsolt Matula
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences; Budapest Hungary
| | - László Homolya
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences; Budapest Hungary
| | - Balázs Sarkadi
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences; Budapest Hungary
- Molecular Biophysics Research Group and Department of Biophysics and Radiation Biology; Semmelweis University; Budapest Hungary
| | - Ágnes Telbisz
- Research Centre for Natural Sciences, Institute of Enzymology, Hungarian Academy of Sciences; Budapest Hungary
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76
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Esser L, Shukla S, Zhou F, Ambudkar SV, Xia D. Crystal structure of the antigen-binding fragment of a monoclonal antibody specific for the multidrug-resistance-linked ABC transporter human P-glycoprotein. Acta Crystallogr F Struct Biol Commun 2016; 72:636-41. [PMID: 27487928 PMCID: PMC4973305 DOI: 10.1107/s2053230x16009778] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 06/16/2016] [Indexed: 12/19/2022] Open
Abstract
P-glycoprotein (P-gp) is a polyspecific ATP-dependent transporter linked to multidrug resistance in cancers that plays important roles in the pharmacokinetics of a large number of drugs. The drug-resistance phenotype of P-gp can be modulated by the monoclonal antibody UIC2, which specifically recognizes human P-gp in a conformation-dependent manner. Here, the purification, sequence determination and high-resolution structure of the Fab fragment of UIC2 (UIC2/Fab) are reported. Purified UIC2/Fab binds human P-gp with a 1:1 stoichiometry. Crystals of UIC2/Fab are triclinic (space group P1), with unit-cell parameters a = 40.67, b = 44.91, c = 58.09 Å, α = 97.62, β = 99.10, γ = 94.09°, and diffracted X-rays to 1.6 Å resolution. The structure was determined by molecular replacement and refined to 1.65 Å resolution. The asymmetric unit contains one molecule of UIC2/Fab, which exhibits a positively charged antigen-binding surface, suggesting that it might recognize an oppositely charged extracellular epitope of P-gp.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/chemistry
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Amino Acid Motifs
- Animals
- Antibodies, Monoclonal/biosynthesis
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/isolation & purification
- Antigens/chemistry
- Antigens/metabolism
- Binding Sites
- Cloning, Molecular
- Crystallography, X-Ray
- Gene Expression
- Humans
- Hybridomas/chemistry
- Immunoglobulin Fab Fragments/biosynthesis
- Immunoglobulin Fab Fragments/chemistry
- Immunoglobulin Fab Fragments/isolation & purification
- Mice
- Mice, Inbred BALB C
- Models, Molecular
- Protein Binding
- Protein Interaction Domains and Motifs
- Protein Structure, Secondary
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/chemistry
- Recombinant Proteins/isolation & purification
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Affiliation(s)
- Lothar Esser
- National Cancer Institute, National Institutes of Health, 37 Convent Drive, Building 37, Bethesda, MD 20892, USA
| | - Suneet Shukla
- National Cancer Institute, National Institutes of Health, 37 Convent Drive, Building 37, Bethesda, MD 20892, USA
| | - Fei Zhou
- National Cancer Institute, National Institutes of Health, 37 Convent Drive, Building 37, Bethesda, MD 20892, USA
| | - Suresh V. Ambudkar
- National Cancer Institute, National Institutes of Health, 37 Convent Drive, Building 37, Bethesda, MD 20892, USA
| | - Di Xia
- National Cancer Institute, National Institutes of Health, 37 Convent Drive, Building 37, Bethesda, MD 20892, USA
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77
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Zheng X, Andruska N, Lambrecht MJ, He S, Parissenti A, Hergenrother PJ, Nelson ER, Shapiro DJ. Targeting multidrug-resistant ovarian cancer through estrogen receptor α dependent ATP depletion caused by hyperactivation of the unfolded protein response. Oncotarget 2016; 9:14741-14753. [PMID: 29599904 PMCID: PMC5871075 DOI: 10.18632/oncotarget.10819] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/10/2016] [Indexed: 12/14/2022] Open
Abstract
Ovarian cancers often recur and tumors acquire resistance to chemotherapy due to overexpression of the ATP-dependent efflux pump, multidrug resistance protein 1 (MDR1/P-glycoprotein/ABCB1). Nontoxic small molecule inhibitors targeting MDR1 have remained largely elusive. Instead, in a novel application of our recently described estrogen receptor α (ERα) biomodulator, BHPI, we targeted MDR1’s substrate, ATP. BHPI depletes intracellular ATP and nearly blocks MDR1-mediated drug efflux in ovarian cancer cells by inducing toxic hyperactivation of the endoplasmic reticulum stress sensor, the unfolded protein response (UPR). BHPI increased sensitivity of MDR1 overexpressing multidrug resistant OVCAR-3 ovarian cancer cells to killing by paclitaxel by >1,000 fold. BHPI also restored doxorubicin sensitivity in OVCAR-3 cells and in MDR1 overexpressing breast cancer cells. In an orthotopic OVCAR-3 xenograft model, paclitaxel was ineffective and the paclitaxel-treated group was uniquely prone to form large secondary tumors in adjacent tissue. BHPI alone strongly reduced tumor growth. Notably, tumors were undetectable in mice treated with BHPI plus paclitaxel. Compared to control ovarian tumors, after the combination therapy, levels of the plasma ovarian cancer biomarker CA125 were at least several hundred folds lower; moreover, CA125 levels progressively declined to undetectable. Targeting MDR1 through UPR-dependent ATP depletion represents a promising therapeutic strategy.
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Affiliation(s)
- Xiaobin Zheng
- Department of Biochemistry University of Illinois, Urbana, IL, USA
| | - Neal Andruska
- Department of Biochemistry University of Illinois, Urbana, IL, USA.,College of Medicine, University of Illinois, Urbana, IL, USA
| | | | - Sisi He
- Department of Molecular Integrative Physiology, University of Illinois, Urbana, IL, USA
| | - Amadeo Parissenti
- Cancer Research Program, Advanced Medical Research Institute of Canada, Sudbury, ON, Canada
| | | | - Erik R Nelson
- Department of Molecular Integrative Physiology, University of Illinois, Urbana, IL, USA.,University of Illinois Cancer Center, Urbana, IL, USA
| | - David J Shapiro
- Department of Biochemistry University of Illinois, Urbana, IL, USA.,University of Illinois Cancer Center, Urbana, IL, USA.,College of Medicine, University of Illinois, Urbana, IL, USA
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78
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Seebacher N, Lane DJR, Richardson DR, Jansson PJ. Turning the gun on cancer: Utilizing lysosomal P-glycoprotein as a new strategy to overcome multi-drug resistance. Free Radic Biol Med 2016; 96:432-45. [PMID: 27154979 DOI: 10.1016/j.freeradbiomed.2016.04.201] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 04/01/2016] [Accepted: 04/29/2016] [Indexed: 01/02/2023]
Abstract
Oxidative stress plays a role in the development of drug resistance in cancer cells. Cancer cells must constantly and rapidly adapt to changes in the tumor microenvironment, due to alterations in the availability of nutrients, such as glucose, oxygen and key transition metals (e.g., iron and copper). This nutrient flux is typically a consequence of rapid growth, poor vascularization and necrosis. It has been demonstrated that stress factors, such as hypoxia and glucose deprivation up-regulate master transcription factors, namely hypoxia inducible factor-1α (HIF-1α), which transcriptionally regulate the multi-drug resistance (MDR), transmembrane drug efflux transporter, P-glycoprotein (Pgp). Interestingly, in addition to the established role of plasma membrane Pgp in MDR, a new paradigm of intracellular resistance has emerged that is premised on the ability of lysosomal Pgp to transport cytotoxic agents into this organelle. This mechanism is enabled by the topological inversion of Pgp via endocytosis resulting in the transporter actively pumping agents into the lysosome. In this way, classical Pgp substrates, such as doxorubicin (DOX), can be actively transported into this organelle. Within the lysosome, DOX becomes protonated upon acidification of the lysosomal lumen, causing its accumulation. This mechanism efficiently traps DOX, preventing its cytotoxic interaction with nuclear DNA. This review discusses these effects and highlights a novel mechanism by which redox-active and protonatable Pgp substrates can utilize lysosomal Pgp to gain access to this compartment, resulting in catastrophic lysosomal membrane permeabilization and cell death. Hence, a key MDR mechanism that utilizes Pgp (the "gun") to sequester protonatable drug substrates safely within lysosomes can be "turned on" MDR cancer cells to destroy them from within.
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Affiliation(s)
- Nicole Seebacher
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Blackburn Building (D06), University of Sydney, Sydney, New South Wales 2006, Australia
| | - Darius J R Lane
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Blackburn Building (D06), University of Sydney, Sydney, New South Wales 2006, Australia
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Blackburn Building (D06), University of Sydney, Sydney, New South Wales 2006, Australia
| | - Patric J Jansson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Blackburn Building (D06), University of Sydney, Sydney, New South Wales 2006, Australia
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79
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El-Sheikh AAK, Morsy MA, Al-Taher AY. Protective mechanisms of resveratrol against methotrexate-induced renal damage may involve BCRP/ABCG2. Fundam Clin Pharmacol 2016; 30:406-18. [DOI: 10.1111/fcp.12205] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 04/27/2016] [Accepted: 05/19/2016] [Indexed: 12/26/2022]
Affiliation(s)
- Azza A. K. El-Sheikh
- Department of Pharmacology; Faculty of Medicine; Minia University; El-Minia 61511 Egypt
| | - Mohamed A. Morsy
- Department of Pharmacology; Faculty of Medicine; Minia University; El-Minia 61511 Egypt
- Department of Pharmaceutical Sciences; College of Clinical Pharmacy; King Faisal University; Al-Ahsa 31982 Saudi Arabia
| | - Abdulla Y. Al-Taher
- Department of Physiology, Biochemistry and Pharmacology; College of Veterinary Medicine; King Faisal University; Al-Ahsa 31982 Saudi Arabia
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80
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Hegyi Z, Homolya L. Functional Cooperativity between ABCG4 and ABCG1 Isoforms. PLoS One 2016; 11:e0156516. [PMID: 27228027 PMCID: PMC4882005 DOI: 10.1371/journal.pone.0156516] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/16/2016] [Indexed: 11/18/2022] Open
Abstract
ABCG4 belongs to the ABCG subfamily, the members of which are half transporters composed of a single transmembrane and a single nucleotide-binding domain. ABCG proteins have a reverse domain topology as compared to other mammalian ABC transporters, and have to form functional dimers, since the catalytic sites for ATP binding and hydrolysis, as well as the transmembrane domains are composed of distinct parts of the monomers. Here we demonstrate that ABCG4 can form homodimers, but also heterodimers with its closest relative, ABCG1. Both the full-length and the short isoforms of ABCG1 can dimerize with ABCG4, whereas the ABCG2 multidrug transporter is unable to form a heterodimer with ABCG4. We also show that contrary to that reported in some previous studies, ABCG4 is predominantly localized to the plasma membrane. While both ABCG1 and ABCG4 have been suggested to be involved in lipid transport or regulation, in accordance with our previous results regarding the long version of ABCG1, here we document that the expression of both the short isoform of ABCG1 as well as ABCG4 induce apoptosis in various cell types. This apoptotic effect, as a functional read-out, allowed us to demonstrate that the dimerization between these half transporters is not only a physical interaction but functional cooperativity. Given that ABCG4 is predominantly expressed in microglial-like cells and endothelial cells in the brain, our finding of ABCG4-induced apoptosis may implicate a new role for this protein in the clearance mechanisms within the central nervous system.
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Affiliation(s)
- Zoltán Hegyi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - László Homolya
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
- * E-mail:
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81
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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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82
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A single active catalytic site is sufficient to promote transport in P-glycoprotein. Sci Rep 2016; 6:24810. [PMID: 27117502 PMCID: PMC4846820 DOI: 10.1038/srep24810] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 04/05/2016] [Indexed: 11/23/2022] Open
Abstract
P-glycoprotein (Pgp) is an ABC transporter responsible for the ATP-dependent efflux of chemotherapeutic compounds from multidrug resistant cancer cells. Better understanding of the molecular mechanism of Pgp-mediated transport could promote rational drug design to circumvent multidrug resistance. By measuring drug binding affinity and reactivity to a conformation-sensitive antibody we show here that nucleotide binding drives Pgp from a high to a low substrate-affinity state and this switch coincides with the flip from the inward- to the outward-facing conformation. Furthermore, the outward-facing conformation survives ATP hydrolysis: the post-hydrolytic complex is stabilized by vanadate, and the slow recovery from this state requires two functional catalytic sites. The catalytically inactive double Walker A mutant is stabilized in a high substrate affinity inward-open conformation, but mutants with one intact catalytic center preserve their ability to hydrolyze ATP and to promote drug transport, suggesting that the two catalytic sites are randomly recruited for ATP hydrolysis.
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83
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Nicklisch SCT, Rees SD, McGrath AP, Gökirmak T, Bonito LT, Vermeer LM, Cregger C, Loewen G, Sandin S, Chang G, Hamdoun A. Global marine pollutants inhibit P-glycoprotein: Environmental levels, inhibitory effects, and cocrystal structure. SCIENCE ADVANCES 2016; 2:e1600001. [PMID: 27152359 PMCID: PMC4846432 DOI: 10.1126/sciadv.1600001] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 03/21/2016] [Indexed: 05/05/2023]
Abstract
The world's oceans are a global reservoir of persistent organic pollutants to which humans and other animals are exposed. Although it is well known that these pollutants are potentially hazardous to human and environmental health, their impacts remain incompletely understood. We examined how persistent organic pollutants interact with the drug efflux transporter P-glycoprotein (P-gp), an evolutionarily conserved defense protein that is essential for protection against environmental toxicants. We identified specific congeners of organochlorine pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers that inhibit mouse and human P-gp, and determined their environmental levels in yellowfin tuna from the Gulf of Mexico. In addition, we solved the cocrystal structure of P-gp bound to one of these inhibitory pollutants, PBDE (polybrominated diphenyl ether)-100, providing the first view of pollutant binding to a drug transporter. The results demonstrate the potential for specific binding and inhibition of mammalian P-gp by ubiquitous congeners of persistent organic pollutants present in fish and other foods, and argue for further consideration of transporter inhibition in the assessment of the risk of exposure to these chemicals.
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Affiliation(s)
- Sascha C. T. Nicklisch
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093–0202, USA
| | - Steven D. Rees
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093–0657, USA
| | - Aaron P. McGrath
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093–0657, USA
| | - Tufan Gökirmak
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093–0202, USA
| | - Lindsay T. Bonito
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093–0202, USA
| | - Lydia M. Vermeer
- Sekisui XenoTech, LLC, 1101 West Cambridge Circle Drive, Kansas City, KS 66103, USA
| | - Cristina Cregger
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093–0657, USA
| | - Greg Loewen
- Sekisui XenoTech, LLC, 1101 West Cambridge Circle Drive, Kansas City, KS 66103, USA
| | - Stuart Sandin
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093–0202, USA
| | - Geoffrey Chang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093–0657, USA
- Department of Pharmacology, School of Medicine, University of California San Diego, La Jolla, CA 92093–0657, USA
| | - Amro Hamdoun
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093–0202, USA
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84
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Keiter S, Burkhardt-Medicke K, Wellner P, Kais B, Färber H, Skutlarek D, Engwall M, Braunbeck T, Keiter SH, Luckenbach T. Does perfluorooctane sulfonate (PFOS) act as chemosensitizer in zebrafish embryos? THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 548-549:317-324. [PMID: 26803730 DOI: 10.1016/j.scitotenv.2015.12.089] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/19/2015] [Accepted: 12/19/2015] [Indexed: 06/05/2023]
Abstract
Earlier studies have shown that perfluorooctane sulfonate (PFOS) increases the toxicity of other chemicals by enhancing their uptake by cells and tissues. The present study aimed at testing whether the underlying mechanism of enhanced uptake of chemicals by zebrafish (Danio rerio) embryos in the presence of PFOS is by interference of this compound with the cellular efflux transporter Abcb4. Modifications of uptake/clearance and toxicity of two Abcb4 substrates, the fluorescent dye rhodamine B (RhB) and vinblastine, by PFOS were evaluated using 24 and 48h post-fertilization (hpf) embryos. Upon 90min exposure of 24hpf embryos to 1μM RhB and different PFOS concentrations (3-300μM) accumulation of RhB in zebrafish was increased by up to 11.9-fold compared to controls, whereas RhB increases in verapamil treatments were 1.7-fold. Co-administration of PFOS and vinblastine in exposures from 0 to 48hpf resulted in higher vinblastine-caused mortalities in zebrafish embryos indicating increased uptake of this compound. Interference of PFOS with zebrafish Abcb4 activity was further studied using recombinant protein obtained with the baculovirus expression system. PFOS lead to a concentration-dependent decrease of the verapamil-stimulated Abcb4 ATPase activity; at higher PFOS concentrations (250, 500μM), also the basal ATPase activity was lowered indicating PFOS to be an Abcb4 inhibitor. In exposures of 48hpf embryos to a very high RhB concentration (200μM), accumulation of RhB in embryo tissue and adsorption to the chorion were increased in the presence of 50 or 100μM PFOS. In conclusion, the results indicate that PFOS acts as inhibitor of zebrafish Abcb4; however, the exceptionally large PFOS-caused effect amplitude of RhB accumulation in the 1μM RhB experiments and the clear PFOS effects in the experiments with 200μM RhB suggest that an additional mechanism appears to be responsible for the potential of PFOS to enhance uptake of Abcb4 substrates.
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Affiliation(s)
- Susanne Keiter
- Aquatic Ecology and Toxicology Group, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, D-69120 Heidelberg, Germany.
| | - Kathleen Burkhardt-Medicke
- Department Bioanalytical Ecotoxicology, UFZ-Helmholtz Centre for Environmental Research, Permoserstr. 15, D-04318 Leipzig, Germany; Institute of Hydrobiology, Dresden University of Technology, D-01062 Dresden, Germany
| | - Peggy Wellner
- Department Bioanalytical Ecotoxicology, UFZ-Helmholtz Centre for Environmental Research, Permoserstr. 15, D-04318 Leipzig, Germany
| | - Britta Kais
- Aquatic Ecology and Toxicology Group, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, D-69120 Heidelberg, Germany
| | - Harald Färber
- Institute for Hygiene and Public Health, University of Bonn, Sigmund-Freudstr. 25, D-53127 Bonn, Germany
| | - Dirk Skutlarek
- Institute for Hygiene and Public Health, University of Bonn, Sigmund-Freudstr. 25, D-53127 Bonn, Germany
| | - Magnus Engwall
- Man-Technology-Environment Research Centre (MTM), Department of Natural Science, University of Örebro, Fakultetsgatan 1, S-701 12 Örebro, Sweden
| | - Thomas Braunbeck
- Aquatic Ecology and Toxicology Group, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, D-69120 Heidelberg, Germany
| | - Steffen H Keiter
- Man-Technology-Environment Research Centre (MTM), Department of Natural Science, University of Örebro, Fakultetsgatan 1, S-701 12 Örebro, Sweden
| | - Till Luckenbach
- Department Bioanalytical Ecotoxicology, UFZ-Helmholtz Centre for Environmental Research, Permoserstr. 15, D-04318 Leipzig, Germany.
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85
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Loo TW, Clarke DM. P-glycoprotein ATPase activity requires lipids to activate a switch at the first transmission interface. Biochem Biophys Res Commun 2016; 472:379-83. [PMID: 26944019 DOI: 10.1016/j.bbrc.2016.02.124] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 02/29/2016] [Indexed: 01/31/2023]
Abstract
P-glycoprotein (P-gp) is an ABC (ATP-Binding Cassette) drug pump. A common feature of ABC proteins is that they are organized into two wings. Each wing contains a transmembrane domain (TMD) and a nucleotide-binding domain (NBD). Drug substrates and ATP bind at the interface between the TMDs and NBDs, respectively. Drug transport involves ATP-dependent conformational changes between inward- (open, NBDs far apart) and outward-facing (closed, NBDs close together) conformations. P-gps crystallized in the presence of detergent show an open structure. Human P-gp is inactive in detergent but basal ATPase activity is restored upon addition of lipids. The lipids might cause closure of the wings to bring the NBDs close together to allow ATP hydrolysis. We show however, that cross-linking the wings together did not activate ATPase activity when lipids were absent suggesting that lipids may induce other structural changes required for ATPase activity. We then tested the effect of lipids on disulfide cross-linking of mutants at the first transmission interface between intracellular loop 4 (TMD2) and NBD1. Mutants L443C/S909C and L443C/R905C but not G471C/S909C and V472C/S909C were cross-linked with oxidant when in membranes. The mutants were then purified and cross-linked with or without lipids. Mutants G471C/S909C and V472C/S909C cross-linked only in the absence of lipids whereas mutants L443C/S909C and L443C/R905C were cross-linked only in the presence of lipids. The results suggest that lipids activate a switch at the first transmission interface and that the structure of P-gp is different in detergents and lipids.
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Affiliation(s)
- Tip W Loo
- Department of Medicine and Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - David M Clarke
- Department of Medicine and Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
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86
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Gutay-Tóth Z, Fenyvesi F, Bársony O, Szente L, Goda K, Szabó G, Bacsó Z. Cholesterol-dependent conformational changes of P-glycoprotein are detected by the 15D3 monoclonal antibody. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:188-95. [DOI: 10.1016/j.bbalip.2015.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/23/2015] [Accepted: 12/11/2015] [Indexed: 01/08/2023]
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87
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Gonzalez-Lobato L, Chaptal V, Molle J, Falson P. Leishmania tarentolae as a Promising Tool for Expressing Polytopic and Multi-Transmembrane Spans Eukaryotic Membrane Proteins: The Case of the ABC Pump ABCG6. Methods Mol Biol 2016; 1432:119-31. [PMID: 27485333 DOI: 10.1007/978-1-4939-3637-3_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This chapter includes a practical method of membrane protein production in Leishmania tarentolae cells. We routinely use it to express membrane proteins of the ABC (adenosine triphosphate-binding cassette) family, here exemplified with ABCG6 from L. braziliensis, implicated in phospholipid trafficking and drug efflux. The pLEXSY system used here allows membrane protein production with a mammalian-like N-glycosylation pattern, at high levels and at low costs. Also the effects of an N-terminal truncation of the protein are described. The method is described to allow any kind of membrane protein production.
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Affiliation(s)
- Lucia Gonzalez-Lobato
- Drug Resistance and Membrane Proteins Team, UMR CNRS-UCBL1 5086, IBCP, 7, passage du Vercors, 69367, Lyon, France
| | - Vincent Chaptal
- Drug Resistance and Membrane Proteins Team, UMR CNRS-UCBL1 5086, IBCP, 7, passage du Vercors, 69367, Lyon, France
| | - Jennifer Molle
- Drug Resistance and Membrane Proteins Team, UMR CNRS-UCBL1 5086, IBCP, 7, passage du Vercors, 69367, Lyon, France
| | - Pierre Falson
- Drug Resistance and Membrane Proteins Team, UMR CNRS-UCBL1 5086, IBCP, 7, passage du Vercors, 69367, Lyon, France.
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88
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Li G, Li M, Xu W, Zhou Q, Hu Z, Tang Q, Chen K, Yao Q. Regulation of BmBDV NS1 by phosphorylation: Impact of mutagenesis at consensus phosphorylation sites on ATPase activity and cytopathic effects. J Invertebr Pathol 2015; 133:66-72. [PMID: 26686834 DOI: 10.1016/j.jip.2015.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 11/30/2015] [Accepted: 12/09/2015] [Indexed: 12/21/2022]
Abstract
Bombyx mori bidensovirus (BmBDV) is a single-stranded DNA virus belonging to the Bidensovirus genus, Bidnaviridae family. Previous studies showed that parvovirus nonstructural protein 1 (NS1) contains endonuclease, helicase, and ATPase activities and that these activities are regulated by serine/threonine phosphorylation. We have reported that residue Thr-184 site of BmBDV NS1 is phosphorylated, and that residues of Thr-181 and Thr-191 are potentially phosphorylated. However, whether phosphorylation affects BmBDV NS1 activities remains unclear. In this study, the substitution of threonine with Glycine at positions 181, 184 and 191 of BmBDV NS1 reduced its ATPase activity. After wild-type NS1 was treated with calf intestinal alkaline phosphatase (CIP), ATPase activity decreased significantly. Moreover, silkworms that were injected with recombinant viruses carrying these NS1 mutations exhibited significant increases in the median lethal time to death compared with silkworms that were injected with a virus that expressed wild-type NS1. In conclusion, these results showed that the ATPase activity and virulence of BmBDV NS1 are regulated via phosphorylation.
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Affiliation(s)
- Guohui Li
- Institute of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China.
| | - Mangmang Li
- Institute of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Wu Xu
- Institute of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Qian Zhou
- Institute of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Zhaoyang Hu
- Institute of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Qi Tang
- Institute of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Keping Chen
- Institute of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Qin Yao
- Institute of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
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89
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Cheng Y, Woolf TF, Gan J, He K. In vitro model systems to investigate bile salt export pump (BSEP) activity and drug interactions: A review. Chem Biol Interact 2015; 255:23-30. [PMID: 26683212 DOI: 10.1016/j.cbi.2015.11.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 11/10/2015] [Accepted: 11/26/2015] [Indexed: 01/04/2023]
Abstract
The bile salt export pump protein (BSEP), expressed on the canalicular membranes of hepatocytes, is primarily responsible for the biliary excretion of bile salts. The inhibition of BSEP transport activity can lead to an increase in intracellular bile salt levels and liver injury. This review discusses the various in vitro assays currently available for assessing the effect of drugs or other chemical entities to modulate BSEP transport activity. BSEP transporter assays use one of the following platforms: Xenopus laevis oocytes; canalicular membrane vesicles (CMV); BSEP-expressed membrane vesicles; cell lines expressing BSEP; sandwich cultured hepatocytes (SCH); and hepatocytes in suspension. Two of these, BSEP-expressed insect membrane vesicles and sandwich cultured hepatocytes, are the most commonly used assays. BSEP membrane vesicles prepared from transfected insect cells are useful for assessing BSEP inhibition or substrate specificity and exploring mechanisms of BSEP-associated genetic diseases. This model can be applied in a high-throughput format for discovery-drug screening. However, experimental results from use of membrane vesicles may lack physiological relevance and the model does not allow for investigation of in situ metabolism in modulation of BSEP activity. Hepatocyte-based assays that use the SCH format provide results that are generally more physiologically relevant than membrane assays. The SCH model is useful in detailed studies of the biliary excretion of drugs and BSEP inhibition, but due to the complexity of SCH preparation, this model is used primarily for determining biliary clearance and BSEP inhibition in a limited number of compounds. The newly developed hepatocyte in suspension assay avoids many of the complexities of the SCH method. The use of pooled cryopreserved hepatocytes in suspension minimizes genetic variance and individual differences in BSEP activity and also provides the opportunity for higher throughput screening and cross-species comparisons.
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Affiliation(s)
- Yaofeng Cheng
- Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Company, Princeton, NJ 08543, USA
| | | | - Jinping Gan
- Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Company, Princeton, NJ 08543, USA
| | - Kan He
- Biotranex LLC, Monmouth Junction, NJ 08852, USA.
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90
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Effects of the ABCB1 (1199G > A) Polymorphism on Steroid Sex Hormone-Induced P-Glycoprotein Expression, ATPase Activity, and Hormone Efflux. Med Sci (Basel) 2015; 3:124-137. [PMID: 29083397 PMCID: PMC5635765 DOI: 10.3390/medsci3040124] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 11/10/2015] [Accepted: 11/16/2015] [Indexed: 01/15/2023] Open
Abstract
This study examined how the 1199G > A polymorphism in the ABCB1 gene encoding P-glycoprotein (P-gp) affects the protein’s expression, ATPase activity, and ability to pump female steroid sex hormones out of LLC-PK1 cells. The ABCB1 (1199G) or ABCB1 (1199A) allele was transfected into cells, which were incubated for 48 h with various hormone concentrations, then analyzed by Western blotting to examine expression of P-gp protein and by reverse transcription-polymerase chain reaction (RT-PCR) to examine expression of mRNA. Cells were also compared in terms of their transepithelial permeability to steroid sex hormones in the presence and absence of the specific P-gp inhibitor GF120918. P-gp ATPase activity induced by steroid sex hormones was also assayed. Estriol and ethynyl estradiol up-regulated levels of ABCB1 mRNA in a concentration-dependent manner, with ABCB1 (1199A) mRNA showing greater up-regulation than ABCB1 (1199G) mRNA. Estrone, estriol, and ethynyl estradiol were substrates of both types of P-gp in transepithelial permeability assays, and the ABCB1 (1199A) protein showed a significantly higher net efflux ratio for estrone (13.4 vs. 7.4, p < 0.005), estriol (5.6 vs. 3.3, p < 0.05), and ethynyl estradiol (12.7 vs. 5.3, p < 0.005). Induction of P-gp ATPase activity by ethynyl estradiol and progesterone increased with increasing hormone concentration, and the magnitude of stimulation was greater for ABCB1 (1199A) P-gp than for ABCB1 (1199G) P-gp. These results indicate that the ABCB1 (1199G > A) polymorphism influences steroid sex hormone-induced expression and function of P-gp, which may help to explain inter-patient differences in P-gp-mediated chemotherapy resistance in vivo.
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91
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Loo TW, Clarke DM. Mapping the Binding Site of the Inhibitor Tariquidar That Stabilizes the First Transmembrane Domain of P-glycoprotein. J Biol Chem 2015; 290:29389-401. [PMID: 26507655 PMCID: PMC4705942 DOI: 10.1074/jbc.m115.695171] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Indexed: 11/26/2022] Open
Abstract
ABC (ATP-binding cassette) transporters are clinically important because drug pumps like P-glycoprotein (P-gp, ABCB1) confer multidrug resistance and mutant ABC proteins are responsible for many protein-folding diseases such as cystic fibrosis. Identification of the tariquidar-binding site has been the subject of intensive molecular modeling studies because it is the most potent inhibitor and corrector of P-gp. Tariquidar is a unique P-gp inhibitor because it locks the pump in a conformation that blocks drug efflux but activates ATPase activity. In silico docking studies have identified several potential tariquidar-binding sites. Here, we show through cross-linking studies that tariquidar most likely binds to sites within the transmembrane (TM) segments located in one wing or at the interface between the two wings (12 TM segments form 2 divergent wings). We then introduced arginine residues at all positions in the 12 TM segments (223 mutants) of P-gp. The rationale was that a charged residue in the drug-binding pocket would disrupt hydrophobic interaction with tariquidar and inhibit its ability to rescue processing mutants or stimulate ATPase activity. Arginines introduced at 30 positions significantly inhibited tariquidar rescue of a processing mutant and activation of ATPase activity. The results suggest that tariquidar binds to a site within the drug-binding pocket at the interface between the TM segments of both structural wings. Tariquidar differed from other drug substrates, however, as it stabilized the first TM domain. Stabilization of the first TM domain appears to be a key mechanism for high efficiency rescue of ABC processing mutants that cause disease.
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Affiliation(s)
- Tip W Loo
- From the Departments of Medicine and Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - David M Clarke
- From the Departments of Medicine and Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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92
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Kurth D, Brack W, Luckenbach T. Is chemosensitisation by environmental pollutants ecotoxicologically relevant? AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 167:134-42. [PMID: 26281775 DOI: 10.1016/j.aquatox.2015.07.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 07/28/2015] [Accepted: 07/28/2015] [Indexed: 05/11/2023]
Abstract
The active cellular efflux of toxicants is an efficient biological defense mode present in all organisms. By blocking this so-called multixenobiotic resistance transport-a process also referred to as chemosensitisation-, cellular bioaccumulation and the sensitivity of organisms towards environmental pollutants can increase. So far, a wide range of compounds, including pesticides, pharmaceuticals, fragrances, and surfactants, have been identified as chemosensitisers. Although, significant on a cellular level, the environmental impact of chemosensitisation on the organism level is not yet understood. Critically evaluating existing data, this paper identifies research needs to support our tentative conclusion that chemosensitisation may well enhance the risks of chemical exposure to aquatic organisms. Our conclusion is based on studies investigating the impact of individual chemicals and complex environmental mixtures on aquatic wildlife and a chemosensitiser mixture toxicity model which, however, is subject to great uncertainty due to substantial knowledge gaps. Those uncertainties include the inconsistent reporting of effect data, the lack of representative environmental contaminants tested for chemosensitisation, and the publishing of highly unreliable nominal exposure concentrations. In order to confirm the tentative conclusion of this paper, we require the significant and systematic investigation of a broader set of chemicals and environmental samples with a harmonised set of bioassays and rigorously controlled freely dissolved effect concentrations.
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Affiliation(s)
- Denise Kurth
- UFZ-Helmholtz Centre for Environmental Research, Department of Effect-Directed Analysis, Permoserstr. 15, 04318 Leipzig, Germany; RWTH Aachen University, Department of Ecosystem Analyses, Institute for Environmental Research, Worringerweg 1, 52074, Aachen, Germany
| | - Werner Brack
- UFZ-Helmholtz Centre for Environmental Research, Department of Effect-Directed Analysis, Permoserstr. 15, 04318 Leipzig, Germany; RWTH Aachen University, Department of Ecosystem Analyses, Institute for Environmental Research, Worringerweg 1, 52074, Aachen, Germany.
| | - Till Luckenbach
- UFZ-Helmholtz Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstr. 15, 04318 Leipzig, Germany
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93
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Patik I, Kovacsics D, Német O, Gera M, Várady G, Stieger B, Hagenbuch B, Szakács G, Özvegy-Laczka C. Functional expression of the 11 human Organic Anion Transporting Polypeptides in insect cells reveals that sodium fluorescein is a general OATP substrate. Biochem Pharmacol 2015; 98:649-58. [PMID: 26415544 DOI: 10.1016/j.bcp.2015.09.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 09/17/2015] [Indexed: 11/29/2022]
Abstract
Organic Anion Transporting Polypeptides (OATPs), encoded by genes of the Solute Carrier Organic Anion (SLCO) family, are transmembrane proteins involved in the uptake of various compounds of endogenous or exogenous origin. In addition to their physiological roles, OATPs influence the pharmacokinetics and drug-drug interactions of several clinically relevant compounds. To examine the function and molecular interactions of human OATPs, including several poorly characterized family members, we expressed all 11 human OATPs at high levels in the baculovirus-Sf9 cell system. We measured the temperature- and inhibitor-sensitive cellular accumulation of sodium fluorescein and fluorescein-methotrexate, two fluorescent substrates of the OATPs, OATP1B1 and 1B3. OATP1B1 and 1B3 were functional in Sf9 cells, showing rapid uptake (t1/2(fluorescein-methotrexate) 2.64 and 4.16 min, and t1/2(fluorescein) 6.71 and 5.58 min for OATP1B1 and 1B3, respectively) and high-affinity transport (Km(fluorescein-methotrexate) 0.23 and 0.53 μM, and Km(fluorescein) 25.73 and 38.55 μM for OATP1B1 and 1B3, respectively) of both substrates. We found that sodium fluorescein is a general substrate of all human OATPs: 1A2, 1B1, 1B3, 1C1, 2A1, 2B1, 3A1, 4A1, 4C1, 5A1 and 6A1, while fluorescein-methotrexate is only transported by 1B1, 1B3, 1A2 and 2B1. Acidic extracellular pH greatly facilitated fluorescein uptake by all OATPs, and new molecular interactions were detected (between OATP2B1 and Imatinib, OATP3A1, 5A1 and 6A1 and estradiol 17-β-d-glucuronide, and OATP1C1 and 4C1 and prostaglandin E2). These studies demonstrate, for the first time, that the insect cell system is suitable for the functional analysis of the entire human OATP family, and for drug-OATP interaction screening.
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Affiliation(s)
- Izabel Patik
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Daniella Kovacsics
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Orsolya Német
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Melinda Gera
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - György Várady
- Laboratory of Molecular Cell Biology, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital, 8091 Zurich, Switzerland
| | - Bruno Hagenbuch
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KA 66160, USA
| | - Gergely Szakács
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Csilla Özvegy-Laczka
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary.
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94
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Dinaciclib, a cyclin-dependent kinase inhibitor, is a substrate of human ABCB1 and ABCG2 and an inhibitor of human ABCC1 in vitro. Biochem Pharmacol 2015; 98:465-72. [PMID: 26300056 DOI: 10.1016/j.bcp.2015.08.099] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Accepted: 08/17/2015] [Indexed: 12/16/2022]
Abstract
Dinaciclib is a novel cyclin-dependent kinase inhibitor (CDKI) with significant activity against various cancers in vitro and in vivo. ABC efflux transporters play an important role in drug disposition and are responsible for multidrug resistance in cancer cells. Inhibitors and substrates of these transporters may participate in pharmacokinetic drug-drug interactions (DDIs) that alter drug disposition during pharmacotherapy. To assess such risks associated with dinaciclib we evaluated its possible effects on efflux activities of ABCB1, ABCC1 and ABCG2 transporters in vitro. Monolayer transport, XTT cell proliferation, ATPase and intracellular accumulation assays were employed. Here, we show that the transport ratio of dinaciclib was far higher across monolayers of MDCKII-ABCB1 and MDCKII-ABCG2 cells than across MDCKII parental cell layers, demonstrating that dinaciclib is a substrate of ABCB1 and ABCG2. In addition, overexpression of ABCB1, ABCG2 and ABCC1 conferred resistance to dinaciclib in MDCKII cells. In ATPase assays, dinaciclib decreased stimulated ATPase activity of ABCB1, ABCG2 and ABCC1, confirming it has interactive potential toward all three transporters. Moreover, dinaciclib significantly inhibited ABCC1-mediated efflux of daunorubicin (EC50=18 μM). The inhibition of ABCC1 further led to a synergistic effect of dinaciclib in both MDCKII-ABCC1 and human cancer T47D cells, when applied in combination with anticancer drugs. Taken together, our results suggest that ABC transporters can substantially affect dinaciclib transport across cellular membranes, leading to DDIs. The DDIs of dinaciclib with ABCC1 substrate chemotherapeutics might be exploited in novel cancer therapies.
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95
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De Vilder EYG, Hosen MJ, Vanakker OM. The ABCC6 Transporter as a Paradigm for Networking from an Orphan Disease to Complex Disorders. BIOMED RESEARCH INTERNATIONAL 2015; 2015:648569. [PMID: 26356190 PMCID: PMC4555454 DOI: 10.1155/2015/648569] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/15/2015] [Accepted: 06/23/2015] [Indexed: 01/16/2023]
Abstract
The knowledge on the genetic etiology of complex disorders largely results from the study of rare monogenic disorders. Often these common and rare diseases show phenotypic overlap, though monogenic diseases generally have a more extreme symptomatology. ABCC6, the gene responsible for pseudoxanthoma elasticum, an autosomal recessive ectopic mineralization disorder, can be considered a paradigm gene with relevance that reaches far beyond this enigmatic orphan disease. Indeed, common traits such as chronic kidney disease or cardiovascular disorders have been linked to the ABCC6 gene. While during the last decade the awareness of the wide ramifications of ABCC6 has increased significantly, the gene itself and the transmembrane transporter it encodes have not unveiled all of the mysteries that surround them. To gain more insights, multiple approaches are being used including next-generation sequencing, computational methods, and various "omics" technologies. Much effort is made to place the vast amount of data that is gathered in an integrated system-biological network; the involvement of ABCC6 in common disorders provides a good view on the wide implications and potential of such a network. In this review, we summarize the network approaches used to study ABCC6 and the role of this gene in several complex diseases.
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Affiliation(s)
- Eva Y. G. De Vilder
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
- Department of Ophthalmology, Ghent University Hospital, 9000 Ghent, Belgium
| | - Mohammad Jakir Hosen
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
- Department of Genetic Engineering and Biotechnology, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
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96
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Role of the N-terminal transmembrane domain in the endo-lysosomal targeting and function of the human ABCB6 protein. Biochem J 2015; 467:127-39. [PMID: 25627919 PMCID: PMC4410673 DOI: 10.1042/bj20141085] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
ATP-binding cassette, subfamily B (ABCB) 6 is a homodimeric ATP-binding cassette (ABC) transporter present in the plasma membrane and in the intracellular organelles. The intracellular localization of ABCB6 has been a matter of debate, as it has been suggested to reside in the mitochondria and the endo-lysosomal system. Using a variety of imaging modalities, including confocal microscopy and EM, we confirm the endo-lysosomal localization of ABCB6 and show that the protein is internalized from the plasma membrane through endocytosis, to be distributed to multivesicular bodies and lysosomes. In addition to the canonical nucleotide-binding domain (NBD) and transmembrane domain (TMD), ABCB6 contains a unique N-terminal TMD (TMD0), which does not show sequence homology to known proteins. We investigated the functional role of these domains through the molecular dissection of ABCB6. We find that the folding, dimerization, membrane insertion and ATP binding/hydrolysis of the core–ABCB6 complex devoid of TMD0 are preserved. However, in contrast with the full-length transporter, the core–ABCB6 construct is retained at the plasma membrane and does not appear in Rab5-positive endosomes. TMD0 is directly targeted to the lysosomes, without passage to the plasma membrane. Collectively, our results reveal that TMD0 represents an independently folding unit, which is dispensable for catalysis, but has a crucial role in the lysosomal targeting of ABCB6. The intracellular localization of ATP-binding cassette, sub family B (ABCB) 6 is a matter of debate. We show that ABCB6 is internalized from the plasma membrane to multivesicular bodies and lysosomes. Molecular dissection of the ABCB6 protein reveals a role of its N-terminal domain in targeting.
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97
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Interactions of cyclin-dependent kinase inhibitors AT-7519, flavopiridol and SNS-032 with ABCB1, ABCG2 and ABCC1 transporters and their potential to overcome multidrug resistance in vitro. Cancer Chemother Pharmacol 2015; 76:105-16. [PMID: 25986678 DOI: 10.1007/s00280-015-2772-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 05/06/2015] [Indexed: 12/22/2022]
Abstract
PURPOSE ATP-binding cassette (ABC) transporters play an important role in multidrug resistance (MDR) toward anticancer drugs. Here, we evaluated interactions of cyclin-dependent kinase inhibitors (CDKi) AT-7519, flavopiridol and SNS-032 with the following ABC transporters in vitro: P-glycoprotein (ABCB1), breast cancer resistance protein (ABCG2) and multidrug resistance-associated protein 1 (ABCC1). METHODS Inhibitory potency of studied CDKi to the transporters was evaluated by accumulation assays using fluorescent substrates and MDCKII cells overexpressing human ABCB1, ABCG2 or ABCC1. Resistance of transporter-expressing cells to the CDKi was evaluated by XTT proliferation assay. Observed interactions of CDKi were verified by ATPase assay in ABC transporter-expressing Sf9 membrane vesicles. Combination index analysis was additionally performed in ABC transporter-expressing cancer cell lines, HepG2 and T47D. RESULTS Flavopiridol showed a significant inhibitory potency toward ABCG2 and ABCC1. SNS-032 also decreased ABCG2-mediated efflux, while AT-7519 failed to inhibit ABCB1, ABCG2 or ABCC1. Both flavopiridol and SNS-032 showed synergistic antiproliferative effects in combination with relevant ABC transporter substrates such as daunorubicin and topotecan in cancer cells. ABCB1 was found to confer significant resistance to AT-7519 and SNS-032, but not to flavopiridol. In contrast, ABCG2 and ABCC1 conferred resistance to flavopiridol, but not to AT-7519 and SNS-032. CONCLUSION Our data provide detailed information on interactions of flavopiridol, SNS-032 and AT-7519 with ABC transporters, which may help elucidate the pharmacokinetic behavior and toxicity of these compounds. Moreover, we show the ability of flavopiridol and SNS-032, but not AT-7519, to overcome ABC transporter-mediated MDR.
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98
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Fekete Z, Rajnai Z, Nagy T, Jakab KT, Kurunczi A, Gémes K, Herédi-Szabó K, Fülöp F, Tóth GK, Czerwinski M, Loewen G, Krajcsi P. Membrane Assays to Characterize Interaction of Drugs with ABCB1. J Membr Biol 2015; 248:967-77. [DOI: 10.1007/s00232-015-9804-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 04/20/2015] [Indexed: 11/29/2022]
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99
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Arlanov R, Lang T, Jedlitschky G, Schaeffeler E, Ishikawa T, Schwab M, Nies AT. Functional characterization of common protein variants in the efflux transporter ABCC11 and identification of T546M as functionally damaging variant. THE PHARMACOGENOMICS JOURNAL 2015; 16:193-201. [PMID: 25896536 DOI: 10.1038/tpj.2015.27] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 02/23/2015] [Accepted: 03/02/2015] [Indexed: 11/09/2022]
Abstract
Multidrug resistance protein 8 (ABCC11) is an efflux transporter for anionic lipophilic compounds, conferring resistance to antiviral and anticancer agents like 5-fluorouracil (5-FU). ABCC11 missense variants may contribute to variability in drug response but functional consequences, except for the 'earwax variant' c.538G>A, are unknown. Using the 'Screen and Insert' technology, we generated human embryonic kidney 293 cells stably expressing ABCC11 missense variants frequently occurring in different ethnic populations: c.57G>A, c.538G>A, c.950C>A, c.1637C>T, c.1942G>A, c.4032A>G. A series of in silico prediction analyses and in vitro plasma membrane vesicle uptake, immunoblotting and immunolocalization experiments were undertaken to investigate functional consequences. We identified c.1637C>T (T546M), previously associated with 5-FU-related toxicity, as a novel functionally damaging ABCC11 variant exhibiting markedly reduced transport function of 5-FdUMP, the active cytotoxic metabolite of 5-FU. Detailed analysis of 14 subpopulations revealed highest allele frequencies of c.1637C>T in Europeans and Americans (up to 11%) compared with Africans and Asians (up to 3%).
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Affiliation(s)
- R Arlanov
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Stuttgart, Germany
| | - T Lang
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Stuttgart, Germany
| | - G Jedlitschky
- Department of Pharmacology, Center of Drug Absorption and Transport (C_DAT), University Medicine of Greifswald, Greifswald, Germany
| | - E Schaeffeler
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Stuttgart, Germany
| | - T Ishikawa
- RIKEN Center for Life Science Technologies, Yokohama, Japan
| | - M Schwab
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Stuttgart, Germany.,Department of Clinical Pharmacology, Institute of Experimental and Clinical Pharmacology and Toxicology, University Hospital of Tübingen, Tübingen, Germany
| | - A T Nies
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Stuttgart, Germany
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100
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Trencsényi G, Kertész I, Krasznai ZT, Máté G, Szalóki G, Szabó Judit P, Kárpáti L, Krasznai Z, Márián T, Goda K. 2'[(18)F]-fluoroethylrhodamine B is a promising radiotracer to measure P-glycoprotein function. Eur J Pharm Sci 2015; 74:27-35. [PMID: 25857708 DOI: 10.1016/j.ejps.2015.03.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 03/12/2015] [Accepted: 03/31/2015] [Indexed: 12/21/2022]
Abstract
In vivo detection of the emergence of P-glycoprotein (Pgp) mediated multidrug resistance in tumors could be beneficial for patients treated with anticancer drugs. PET technique in combination with appropriate radiotracers could be the most convenient method for detection of Pgp function. Rhodamine derivatives are validated fluorescent probes for measurement of mitochondrial membrane potential and also Pgp function. The aim of this study was to investigate whether 2'[(18)F]-fluoroethylrhodamine B ((18)FRB) a halogenated rhodamine derivative previously synthesized for PET assessment of myocardial perfusion preserved its Pgp substrate character. ATPase assay as well as accumulation experiments carried out using Pgp(+) and Pgp(-) human gynecologic (A2780/A2780(AD) and KB-3-1/KB-V1) and a mouse fibroblast cell pairs (NIH 3T3 and NIH 3T3 MDR1) were applied to study the interaction of (18)FRB with Pgp. ATPase assay proved that (18)FRB is a high affinity substrate of Pgp. Pgp(-) cells accumulated the (18)FRB rapidly in accordance with its lipophilic character. Dissipation of the mitochondrial proton gradient by a proton ionophore CCCP decreased the accumulation of rhodamine 123 (R123) and (18)FRB into Pgp(-) cells. Pgp(+) cells exhibited very low R123 and (18)FRB accumulation (around 1-8% of the Pgp(-) cell lines) which was not sensitive to the mitochondrial proton gradient; rather it was increased by the Pgp inhibitor cyclosporine A (CsA). Based on the above data we conclude that (18)FRB is a high affinity Pgp substrate and consequently a potential PET tracer to detect multidrug resistant tumors as well as the function of physiological barriers expressing Pgp.
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Affiliation(s)
- György Trencsényi
- Department of Nuclear Medicine, University of Debrecen, Nagyerdei krt. 98, H-4032 Debrecen, Hungary
| | - István Kertész
- Department of Nuclear Medicine, University of Debrecen, Nagyerdei krt. 98, H-4032 Debrecen, Hungary
| | - Zoárd T Krasznai
- Department of Obstetrics and Gynecology, University of Debrecen, Nagyerdei krt. 98, H-4032 Debrecen, Hungary
| | - Gábor Máté
- Department of Nuclear Medicine, University of Debrecen, Nagyerdei krt. 98, H-4032 Debrecen, Hungary
| | - Gábor Szalóki
- Department of Biophysics and Cell Biology, University of Debrecen, Nagyerdei krt. 98, H-4032 Debrecen, Hungary
| | - P Szabó Judit
- Department of Nuclear Medicine, University of Debrecen, Nagyerdei krt. 98, H-4032 Debrecen, Hungary
| | - Levente Kárpáti
- Department of Nuclear Medicine, University of Debrecen, Nagyerdei krt. 98, H-4032 Debrecen, Hungary
| | - Zoltán Krasznai
- Department of Biophysics and Cell Biology, University of Debrecen, Nagyerdei krt. 98, H-4032 Debrecen, Hungary
| | - Teréz Márián
- Department of Nuclear Medicine, University of Debrecen, Nagyerdei krt. 98, H-4032 Debrecen, Hungary.
| | - Katalin Goda
- Department of Biophysics and Cell Biology, University of Debrecen, Nagyerdei krt. 98, H-4032 Debrecen, Hungary
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