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Elbahnsi A, Dudas B, Cisternino S, Declèves X, Miteva MA. Mechanistic insights into P-glycoprotein ligand transport and inhibition revealed by enhanced molecular dynamics simulations. Comput Struct Biotechnol J 2024; 23:2548-2564. [PMID: 38989058 PMCID: PMC11233806 DOI: 10.1016/j.csbj.2024.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 06/07/2024] [Accepted: 06/07/2024] [Indexed: 07/12/2024] Open
Abstract
P-glycoprotein (P-gp) plays a crucial role in cellular detoxification and drug efflux processes, transitioning between inward-facing (IF) open, occluded, and outward-facing (OF) states to facilitate substrate transport. Its role is critical in cancer therapy, where P-gp contributes to the multidrug resistance phenotype. In our study, classical and enhanced molecular dynamics (MD) simulations were conducted to dissect the structural and functional features of the P-gp conformational states. Our advanced MD simulations, including kinetically excited targeted MD (ketMD) and adiabatic biasing MD (ABMD), provided deeper insights into state transition and translocation mechanisms. Our findings suggest that the unkinking of TM4 and TM10 helices is a prerequisite for correctly achieving the outward conformation. Simulations of the IF-occluded conformations, characterized by kinked TM4 and TM10 helices, consistently demonstrated altered communication between the transmembrane domains (TMDs) and nucleotide binding domain 2 (NBD2), suggesting the implication of this interface in inhibiting P-gp's efflux function. A particular emphasis was placed on the unstructured linker segment connecting the NBD1 to TMD2 and its role in the transporter's dynamics. With the linker present, we specifically noticed a potential entrance of cholesterol (CHOL) through the TM4-TM6 portal, shedding light on crucial residues involved in accommodating CHOL. We therefore suggest that this entry mechanism could be employed for some P-gp substrates or inhibitors. Our results provide critical data for understanding P-gp functioning and developing new P-gp inhibitors for establishing more effective strategies against multidrug resistance.
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Affiliation(s)
- Ahmad Elbahnsi
- Université Paris Cité, CNRS UMR 8038 CiTCoM, Inserm U1268 MCTR, Paris, France
| | - Balint Dudas
- Université Paris Cité, CNRS UMR 8038 CiTCoM, Inserm U1268 MCTR, Paris, France
| | - Salvatore Cisternino
- Université Paris Cité, Inserm UMRS 1144, Optimisation Thérapeutique en Neuropsychopharmacologie, Paris, France
| | - Xavier Declèves
- Université Paris Cité, Inserm UMRS 1144, Optimisation Thérapeutique en Neuropsychopharmacologie, Paris, France
| | - Maria A. Miteva
- Université Paris Cité, CNRS UMR 8038 CiTCoM, Inserm U1268 MCTR, Paris, France
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2
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De Vecchis D, Schäfer LV. Coupling the role of lipids to the conformational dynamics of the ABC transporter P-glycoprotein. Biophys J 2024:S0006-3495(24)00417-X. [PMID: 38909280 DOI: 10.1016/j.bpj.2024.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/31/2024] [Accepted: 06/18/2024] [Indexed: 06/24/2024] Open
Abstract
The ATP-binding cassette transporter P-glycoprotein (P-gp) is a multidrug efflux pump that is overexpressed in a variety of cancers and associated with the drug-resistance phenomenon. P-gp structures were previously determined in detergent and in nanodiscs, in which different transmembrane helix conformations were found, "straight" and "kinked," respectively, indicating a possible role of the lipid environment on the P-gp structural ensemble. Here, we investigate the dynamic conformational ensembles and protein-lipid interactions of two human P-gp inward-open conformers, straight and kinked, employing all-atom molecular dynamics (MD) simulations in asymmetric multicomponent lipid bilayers that mimic the highly specialized hepatocyte membrane in which P-gp is expressed. The two conformers are found to differ in terms of the accessibility of the substrate cavity. The MD simulations show how cholesterol and different lipid species wedge, snorkel, and partially enter into the cavity of the straight P-gp conformer solved in detergent. However, access to the cavity of the kinked P-gp conformer solved in nanodiscs is restricted. Furthermore, the volume and dynamic fluctuations of the substrate cavity largely differ between the two P-gp conformers and are modulated by the presence (or absence) of cholesterol in the membrane and/or of ATP. From the mechanistic perspective, the findings indicate that the straight conformer likely precedes the kinked conformer in the functional working cycle of P-gp, with the latter conformation representing a post substrate-bound state. The inaccessibility of the main transmembrane cavity in the kinked conformer might be crucial in preventing substrate disengagement and transport withdrawal. Remarkably, in our unbiased MD simulations, one transmembrane helix (TM10) of the straight conformer underwent a spontaneous transition to a kinked conformation, underlining the relevance of both conformations in a native phospholipid environment and revealing structural descriptors defining the transition between the two P-gp conformers.
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Affiliation(s)
- Dario De Vecchis
- Center for Theoretical Chemistry, Ruhr University Bochum, Bochum, Germany.
| | - Lars V Schäfer
- Center for Theoretical Chemistry, Ruhr University Bochum, Bochum, Germany.
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3
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Gong C, Chen S, Tang Y, Chen H, Xie J, Lv Y, Shen Z, Zhu Y, Wang S, Ge RS, Zhao J. Effects of organochlorine pesticides on human and rat 17β-hydroxysteroid dehydrogenase 1 activity: Structure-activity relationship and in silico docking analysis. J Steroid Biochem Mol Biol 2024; 240:106510. [PMID: 38508472 DOI: 10.1016/j.jsbmb.2024.106510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/12/2024] [Accepted: 03/18/2024] [Indexed: 03/22/2024]
Abstract
The objective of this study was to examine the effect of 11 organochlorine pesticides on human and rat 17β-Hydroxysteroid dehydrogenase 1 (17β-HSD1) in human placental and rat ovarian microsome and on estradiol production in BeWo cells. The results showed that the IC50 values for endosulfan, fenhexamid, chlordecone, and rhothane on human 17β-HSD1 were 21.37, 73.25, 92.80, and 117.69 μM. Kinetic analysis revealed that endosulfan acts as a competitive inhibitor, fenhexamid as a mixed/competitive inhibitor, chlordecone and rhothane as a mixed/uncompetitive inhibitor. In BeWo cells, all insecticides except endosulfan significantly decreased estradiol production at 100 μM. For rats, the IC50 values for dimethomorph, fenhexamid, and chlordecone were 11.98, 36.92, and 109.14 μM. Dimethomorph acts as a mixed inhibitor, while fenhexamid acts as a mixed/competitive inhibitor. Docking analysis revealed that endosulfan and fenhexamid bind to the steroid-binding site of human 17β-HSD1. On the other hand, chlordecone and rhothane binds to a different site other than the steroid and NADPH-binding site. Dimethomorph binds to the steroid/NADPH binding site, and fenhexamid binds to the steroid binding site of rat 17β-HSD1. Bivariate correlation analysis showed a positive correlation between IC50 values and LogP for human 17β-HSD1, while a slight negative correlation was observed between IC50 values and the number of HBA. ADMET analysis provided insights into the toxicokinetics and toxicity of organochlorine pesticides. In conclusion, this study identified the inhibitory effects of 3-4 organochlorine pesticides and binding mechanisms on human and rat 17β-HSD1, as well as their impact on hormone production.
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Affiliation(s)
- Chaochao Gong
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Sailing Chen
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Yunbing Tang
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Huiqian Chen
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Jianghuan Xie
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Yanning Lv
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Zhefan Shen
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Yang Zhu
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Shaowei Wang
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Ren-Shan Ge
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Department of Anesthesiology and Perioperative Medicine, the Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou, Zhejiang 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou, Zhejiang 325027, China; Key Laboratory of Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Key Laboratory of Male Health and Environment of Wenzhou, Zhejiang Province 325000, China.
| | - Junzhao Zhao
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China.
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4
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Sajid A, Rahman H, Ambudkar SV. Advances in the structure, mechanism and targeting of chemoresistance-linked ABC transporters. Nat Rev Cancer 2023; 23:762-779. [PMID: 37714963 DOI: 10.1038/s41568-023-00612-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/31/2023] [Indexed: 09/17/2023]
Abstract
Cancer cells frequently display intrinsic or acquired resistance to chemically diverse anticancer drugs, limiting therapeutic success. Among the main mechanisms of this multidrug resistance is the overexpression of ATP-binding cassette (ABC) transporters that mediate drug efflux, and, specifically, ABCB1, ABCG2 and ABCC1 are known to cause cancer chemoresistance. High-resolution structures, biophysical and in silico studies have led to tremendous progress in understanding the mechanism of drug transport by these ABC transporters, and several promising therapies, including irradiation-based immune and thermal therapies, and nanomedicine have been used to overcome ABC transporter-mediated cancer chemoresistance. In this Review, we highlight the progress achieved in the past 5 years on the three transporters, ABCB1, ABCG2 and ABCC1, that are known to be of clinical importance. We address the molecular basis of their broad substrate specificity gleaned from structural information and discuss novel approaches to block the function of ABC transporters. Furthermore, genetic modification of ABC transporters by CRISPR-Cas9 and approaches to re-engineer amino acid sequences to change the direction of transport from efflux to import are briefly discussed. We suggest that current information regarding the structure, mechanism and regulation of ABC transporters should be used in clinical trials to improve the efficiency of chemotherapeutics for patients with cancer.
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Affiliation(s)
- Andaleeb Sajid
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Hadiar Rahman
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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5
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Mattioli R, Ilari A, Colotti B, Mosca L, Fazi F, Colotti G. Doxorubicin and other anthracyclines in cancers: Activity, chemoresistance and its overcoming. Mol Aspects Med 2023; 93:101205. [PMID: 37515939 DOI: 10.1016/j.mam.2023.101205] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/15/2023] [Accepted: 07/17/2023] [Indexed: 07/31/2023]
Abstract
Anthracyclines have been important and effective treatments against a number of cancers since their discovery. However, their use in therapy has been complicated by severe side effects and toxicity that occur during or after treatment, including cardiotoxicity. The mode of action of anthracyclines is complex, with several mechanisms proposed. It is possible that their high toxicity is due to the large set of processes involved in anthracycline action. The development of resistance is a major barrier to successful treatment when using anthracyclines. This resistance is based on a series of mechanisms that have been studied and addressed in recent years. This work provides an overview of the anthracyclines used in cancer therapy. It discusses their mechanisms of activity, toxicity, and chemoresistance, as well as the approaches used to improve their activity, decrease their toxicity, and overcome resistance.
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Affiliation(s)
- Roberto Mattioli
- Dept. Biochemical Sciences A. Rossi Fanelli, Sapienza University of Rome, Rome, Italy
| | - Andrea Ilari
- Institute of Molecular Biology and Pathology, Italian National Research Council IBPM-CNR, Rome, Italy
| | - Beatrice Colotti
- Dept. Biochemical Sciences A. Rossi Fanelli, Sapienza University of Rome, Rome, Italy
| | - Luciana Mosca
- Dept. Biochemical Sciences A. Rossi Fanelli, Sapienza University of Rome, Rome, Italy
| | - Francesco Fazi
- Department of Anatomical, Histological, Forensic & Orthopaedic Sciences, Section of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - Gianni Colotti
- Institute of Molecular Biology and Pathology, Italian National Research Council IBPM-CNR, Rome, Italy.
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6
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Rahman H, Ware MJ, Sajid A, Lusvarghi S, Durell SR, Ambudkar SV. Residues from Homologous Transmembrane Helices 4 and 10 Are Critical for P-Glycoprotein (ABCB1)-Mediated Drug Transport. Cancers (Basel) 2023; 15:3459. [PMID: 37444569 DOI: 10.3390/cancers15133459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/27/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
P-glycoprotein (P-gp, ABCB1) transports structurally dissimilar hydrophobic and amphipathic compounds, including anticancer drugs, thus contributing to multidrug-resistant cancer. Cryo-EM structures of human P-gp revealed that TMHs 4 and 10 contribute to the formation of the drug-binding cavity and undergo conformational changes during drug transport. To assess the role of the conformational changes in TMH4 and TMH10 during drug transport, we generated two mutants (TMH4-7A and TMH10-7A), each containing seven alanine substitutions. Analysis of the drug efflux function of these mutants using 15 fluorescent substrates revealed that most of the substrates were transported, indicating that even seven mutations in an individual helix have no significant effect on transport function. We then designed the TMH4,10-14A mutant combining seven mutations in both TMHs 4 and 10. Interestingly, when the TMH4,10-14A mutant was tested with 15 substrates, there was no efflux observed for fourteen. The basal ATPase activity of the TMH4,10-14A mutant, similar to that of the WT protein, was inhibited by zosuquidar but was not stimulated by verapamil or rhodamine 6G. Molecular dynamics simulations indicated that the mutations cause TMHs 4 and 10 to pack tighter to their proximal helices, reducing their independent mobility. In aggregate, our findings demonstrate the critical role of the residues of homologous TMHs 4 and 10 for substrate transport, consistent with conformational changes observed in the structure of P-gp.
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Affiliation(s)
- Hadiar Rahman
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
| | - Mark J Ware
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
| | - Andaleeb Sajid
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
| | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
| | - Stewart R Durell
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256, USA
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7
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Badiee SA, Isu UH, Khodadadi E, Moradi M. The Alternating Access Mechanism in Mammalian Multidrug Resistance Transporters and Their Bacterial Homologs. MEMBRANES 2023; 13:568. [PMID: 37367772 DOI: 10.3390/membranes13060568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 05/23/2023] [Accepted: 05/27/2023] [Indexed: 06/28/2023]
Abstract
Multidrug resistance (MDR) proteins belonging to the ATP-Binding Cassette (ABC) transporter group play a crucial role in the export of cytotoxic drugs across cell membranes. These proteins are particularly fascinating due to their ability to confer drug resistance, which subsequently leads to the failure of therapeutic interventions and hinders successful treatments. One key mechanism by which multidrug resistance (MDR) proteins carry out their transport function is through alternating access. This mechanism involves intricate conformational changes that enable the binding and transport of substrates across cellular membranes. In this extensive review, we provide an overview of ABC transporters, including their classifications and structural similarities. We focus specifically on well-known mammalian multidrug resistance proteins such as MRP1 and Pgp (MDR1), as well as bacterial counterparts such as Sav1866 and lipid flippase MsbA. By exploring the structural and functional features of these MDR proteins, we shed light on the roles of their nucleotide-binding domains (NBDs) and transmembrane domains (TMDs) in the transport process. Notably, while the structures of NBDs in prokaryotic ABC proteins, such as Sav1866, MsbA, and mammalian Pgp, are identical, MRP1 exhibits distinct characteristics in its NBDs. Our review also emphasizes the importance of two ATP molecules for the formation of an interface between the two binding sites of NBD domains across all these transporters. ATP hydrolysis occurs following substrate transport and is vital for recycling the transporters in subsequent cycles of substrate transportation. Specifically, among the studied transporters, only NBD2 in MRP1 possesses the ability to hydrolyze ATP, while both NBDs of Pgp, Sav1866, and MsbA are capable of carrying out this reaction. Furthermore, we highlight recent advancements in the study of MDR proteins and the alternating access mechanism. We discuss the experimental and computational approaches utilized to investigate the structure and dynamics of MDR proteins, providing valuable insights into their conformational changes and substrate transport. This review not only contributes to an enhanced understanding of multidrug resistance proteins but also holds immense potential for guiding future research and facilitating the development of effective strategies to overcome multidrug resistance, thus improving therapeutic interventions.
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Affiliation(s)
- Shadi A Badiee
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Ugochi H Isu
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Ehsaneh Khodadadi
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Mahmoud Moradi
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
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8
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Meier G, Thavarasah S, Ehrenbolger K, Hutter CAJ, Hürlimann LM, Barandun J, Seeger MA. Deep mutational scan of a drug efflux pump reveals its structure-function landscape. Nat Chem Biol 2023; 19:440-450. [PMID: 36443574 PMCID: PMC7615509 DOI: 10.1038/s41589-022-01205-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 10/10/2022] [Indexed: 11/30/2022]
Abstract
Drug efflux is a common resistance mechanism found in bacteria and cancer cells, but studies providing comprehensive functional insights are scarce. In this study, we performed deep mutational scanning (DMS) on the bacterial ABC transporter EfrCD to determine the drug efflux activity profile of more than 1,430 single variants. These systematic measurements revealed that the introduction of negative charges at different locations within the large substrate binding pocket results in strongly increased efflux activity toward positively charged ethidium, whereas additional aromatic residues did not display the same effect. Data analysis in the context of an inward-facing cryogenic electron microscopy structure of EfrCD uncovered a high-affinity binding site, which releases bound drugs through a peristaltic transport mechanism as the transporter transits to its outward-facing conformation. Finally, we identified substitutions resulting in rapid Hoechst influx without affecting the efflux activity for ethidium and daunorubicin. Hence, single mutations can convert EfrCD into a drug-specific ABC importer.
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Affiliation(s)
- Gianmarco Meier
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Sujani Thavarasah
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Kai Ehrenbolger
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
- Science for Life Laboratory, Umeå University, Umeå, Sweden
| | - Cedric A J Hutter
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
- Linkster Therapeutics AG, Zurich, Switzerland
| | - Lea M Hürlimann
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
- Linkster Therapeutics AG, Zurich, Switzerland
| | - Jonas Barandun
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
- Science for Life Laboratory, Umeå University, Umeå, Sweden
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.
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9
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Inoue Y, Yamaguchi T, Otsuka T, Utsunomiya Y, Pan D, Ogawa H, Kato H. Structure-based alteration of tryptophan residues of the multidrug transporter CmABCB1 to assess substrate binding using fluorescence spectroscopy. Protein Sci 2022; 31:e4331. [PMID: 35634783 PMCID: PMC9123602 DOI: 10.1002/pro.4331] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/01/2022] [Accepted: 04/06/2022] [Indexed: 09/17/2023]
Abstract
ABCB1, also known as P-glycoprotein, is an essential component of many physiological barriers and extrudes a variety of hydrophobic chemicals out of the cell. Structures of ABCB1 provided insights into the structural changes that occur upon ATP binding and the characteristic architecture of the substrate binding site. Yet, the structure-function relationship between substrate binding and transporting still remains largely obscured because there is no robust method for accurately measuring substrate binding constants. The methods currently used cannot identify whether the bound substrates are located in the inner chamber of the molecule in the transmembrane region or not because of the low spatial resolution. Here, we report a system for measuring the affinity of substrate binding to the Cyanidioschyzon merolae ABCB1 (CmABCB1) using site-specific tryptophan (Trp) fluorescence quenching. We designed a CmABCB1 mutant with an extrinsic Trp residue introduced into the inner chamber. Trp fluorescence was quenched by three substrates and one inhibitor, including rhodamine 6G, in a saturable fashion, allowing for accurate estimation of the dissociation constant (KD ) for each molecule. The KD for rhodamine 6G is similar to that determined using a reciprocal fluorescence quenching assay using rhodamine 6G fluorescence, suggesting that Trp fluorescence of the mutant was quenched by the interaction between the extrinsic Trp and substrates bound in the inner chamber. Structural comparison of the ABCB1 structures suggests that the system presented in this study could be ideal method of choice to determine the substrate binding affinities of compounds bound to the chamber of mammalian ABCB1.
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Affiliation(s)
- Yoshiki Inoue
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Tomohiro Yamaguchi
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Tetsuo Otsuka
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Yuto Utsunomiya
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Dongqing Pan
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Haruo Ogawa
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Hiroaki Kato
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
- Advanced Photon Technology DivisionRIKEN Harima Institute at SPring‐8Sayo‐gunHyogoJapan
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10
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Goebel J, Chmielewski J, Hrycyna CA. The roles of the human ATP-binding cassette transporters P-glycoprotein and ABCG2 in multidrug resistance in cancer and at endogenous sites: future opportunities for structure-based drug design of inhibitors. CANCER DRUG RESISTANCE (ALHAMBRA, CALIF.) 2022; 4:784-804. [PMID: 34993424 PMCID: PMC8730335 DOI: 10.20517/cdr.2021.19] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ATP-binding cassette (ABC) transporters P-glycoprotein (P-gp) and ABCG2 are multidrug transporters that confer drug resistance to numerous anti-cancer therapeutics in cell culture. These findings initially created great excitement in the medical oncology community, as inhibitors of these transporters held the promise of overcoming clinical multidrug resistance in cancer patients. However, clinical trials of P-gp and ABCG2 inhibitors in combination with cancer chemotherapeutics have not been successful due, in part, to flawed clinical trial designs resulting from an incomplete molecular understanding of the multifactorial basis of multidrug resistance (MDR) in the cancers examined. The field was also stymied by the lack of high-resolution structural information for P-gp and ABCG2 for use in the rational structure-based drug design of inhibitors. Recent advances in structural biology have led to numerous structures of both ABCG2 and P-gp that elucidated more clearly the mechanism of transport and the polyspecific nature of their substrate and inhibitor binding sites. These data should prove useful helpful for developing even more potent and specific inhibitors of both transporters. As such, although possible pharmacokinetic interactions would need to be evaluated, these inhibitors may show greater effectiveness in overcoming ABC-dependent multidrug resistance in combination with chemotherapeutics in carefully selected subsets of cancers. Another perhaps even more compelling use of these inhibitors may be in reversibly inhibiting endogenously expressed P-gp and ABCG2, which serve a protective role at various blood-tissue barriers. Inhibition of these transporters at sanctuary sites such as the brain and gut could lead to increased penetration by chemotherapeutics used to treat brain cancers or other brain disorders and increased oral bioavailability of these agents, respectively.
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Affiliation(s)
- Jason Goebel
- Department of Chemistry, Purdue University West Lafayette, IN 47907, USA
| | - Jean Chmielewski
- Department of Chemistry, Purdue University West Lafayette, IN 47907, USA
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11
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Frozen motion: how cryo-EM changes the way we look at ABC transporters. Trends Biochem Sci 2021; 47:136-148. [PMID: 34930672 DOI: 10.1016/j.tibs.2021.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/29/2021] [Accepted: 11/29/2021] [Indexed: 12/18/2022]
Abstract
ATP-binding cassette (ABC) transporters are widely present molecular machines that transfer substrates across the cell membrane. ABC transporters are involved in numerous physiological processes and are often clinical targets. Structural biology is fundamental to obtain the molecular details underlying ABC transporter function and suggest approaches to modulate it. Until recently, X-ray crystallography has been the only method capable of providing high-resolution structures of ABC transporters. However, modern cryo-electron microscopy (cryo-EM) opens entirely new ways of studying these dynamic membrane proteins. Cryo-EM enables analyses of targets that resist X-ray crystallography, challenging multicomponent complexes, and the exploration of conformational dynamics. These unique capacities have turned cryo-EM into the dominant technique for structural studies of membrane proteins, including ABC transporters.
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12
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Structure of ABCB1/P-Glycoprotein in the Presence of the CFTR Potentiator Ivacaftor. MEMBRANES 2021; 11:membranes11120923. [PMID: 34940424 PMCID: PMC8703531 DOI: 10.3390/membranes11120923] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/16/2021] [Accepted: 11/23/2021] [Indexed: 12/26/2022]
Abstract
ABCB1/P-glycoprotein is an ATP binding cassette transporter that is involved in the clearance of xenobiotics, and it affects the disposition of many drugs in the body. Conformational flexibility of the protein within the membrane is an intrinsic part of its mechanism of action, but this has made structural studies challenging. Here, we have studied different conformations of P-glycoprotein simultaneously in the presence of ivacaftor, a known competitive inhibitor. In order to conduct this, we used high contrast cryo-electron microscopy imaging with a Volta phase plate. We associate the presence of ivacaftor with the appearance of an additional density in one of the conformational states detected. The additional density is in the central aqueous cavity and is associated with a wider separation of the two halves of the transporter in the inward-facing state. Conformational changes to the nucleotide-binding domains are also observed and may help to explain the stimulation of ATPase activity that occurs when transported substrate is bound in many ATP binding cassette transporters.
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13
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Nicklisch SCT, Pouv AK, Rees SD, McGrath AP, Chang G, Hamdoun A. Transporter-interfering chemicals inhibit P-glycoprotein of yellowfin tuna (Thunnus albacares). Comp Biochem Physiol C Toxicol Pharmacol 2021; 248:109101. [PMID: 34116183 DOI: 10.1016/j.cbpc.2021.109101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 05/07/2021] [Accepted: 05/31/2021] [Indexed: 02/08/2023]
Abstract
Marine pollutants bioaccumulate at high trophic levels of marine food webs and are transferred to humans through consumption of apex species. Yellowfin tuna (Thunnus albacares) are marine predators, and one of largest commercial fisheries in the world. Previous studies have shown that yellowfin tuna can accumulate high levels of persistent organic pollutants, including Transporter Interfering Chemicals (TICs), which are chemicals shown to bind to mammalian xenobiotic transporters and interfere with their function. Here, we examined the extent to which these same compounds might interfere with the activity of the yellowfin tuna (Thunnus albacares) ortholog of this transporter. To accomplish this goal we identified, expressed, and functionally assayed tuna ABCB1. The results demonstrated a common mode of vertebrate ABCB1 interaction with TICs that predicts effects across these species, based on high conservation of specific interacting residues. Importantly several TICs showed potent inhibition of Ta-ABCB1, such as the organochlorine pesticides Endrin (EC50 = 1.2 ± 0.2 μM) and Mirex (EC50 = 2.3 ± 0.9 μM). However, unlike the effects observed on mouse ABCB1, low concentrations of the organochlorine pesticide TICs p,p'-DDT and its metabolite p,p'-DDD co-stimulated verapamil-induced Ta-ABCB1 ATPase activity possibly suggesting a low transport activity for these ligands in tuna. These results provide a mechanistic basis for understanding the potential vulnerability of tuna to these ubquitous pollutants.
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Affiliation(s)
- Sascha C T Nicklisch
- Department of Environmental Toxicology, University of California, Davis, Davis, CA 95616, United States of America.
| | - Amara K Pouv
- Department of Environmental Toxicology, University of California, Davis, Davis, CA 95616, United States of America.
| | - Steven D Rees
- Skaggs School of Pharmacy and Pharmaceutical Sciences, 9500 Gilman Drive #0754, University of California, San Diego, La Jolla, CA 92093, United States of America.
| | - Aaron P McGrath
- Skaggs School of Pharmacy and Pharmaceutical Sciences, 9500 Gilman Drive #0754, University of California, San Diego, La Jolla, CA 92093, United States of America
| | - Geoffrey Chang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, 9500 Gilman Drive #0754, University of California, San Diego, La Jolla, CA 92093, United States of America.
| | - Amro Hamdoun
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0202, United States of America.
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14
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Ganesan M, Kanimozhi G, Pradhapsingh B, Khan HA, Alhomida AS, Ekhzaimy A, Brindha GR, Prasad NR. Phytochemicals reverse P-glycoprotein mediated multidrug resistance via signal transduction pathways. Biomed Pharmacother 2021; 139:111632. [PMID: 34243600 DOI: 10.1016/j.biopha.2021.111632] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/09/2021] [Accepted: 04/13/2021] [Indexed: 02/08/2023] Open
Abstract
P-glycoprotein, encoded by ATP-binding cassette transporters B1 gene (ABCB1), renders multidrug resistance (MDR) during cancer chemotherapy. Several synthetic small molecule inhibitors affect P-glycoprotein (P-gp) transport function in MDR tumor cells. However, inhibition of P-gp transport function adversely accumulates chemotherapeutic drugs in non-target normal tissues. Moreover, most small-molecule P-gp inhibitors failed in the clinical trials due to the low therapeutic window at the maximum tolerated dose. Therefore, downregulation of ABCB1-gene expression (P-gp) in tumor tissues seems to be a novel approach rather than inhibiting its transport function for the reversal of multidrug resistance (MDR). Several plant-derived phytochemicals modulate various signal transduction pathways and inhibit translocation of transcription factors, thereby reverses P-gp mediated MDR in tumor cells. Therefore, phytochemicals may be considered an alternative to synthetic small molecule P-gp inhibitors for the reversal of MDR in cancer cells. This review discussed the role of natural phytochemicals that modulate ABCB1 expression through various signal transduction pathways in MDR cancer cells. Therefore, modulating the cell signaling pathways by phytochemicals might play crucial roles in modulating ABCB1 gene expression and the reversal of MDR.
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Affiliation(s)
- M Ganesan
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalainagar 608002, Tamil Nadu, India
| | - G Kanimozhi
- Department of Biochemistry, Dharmapuram Gnanambigai Government Arts College for Women, Mayiladuthurai, Tamil Nadu, India
| | - B Pradhapsingh
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalainagar 608002, Tamil Nadu, India
| | - Haseeb A Khan
- Department of Biochemistry, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Abdullah S Alhomida
- Department of Biochemistry, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Aishah Ekhzaimy
- Division of Endocrinology, Department of Medicine, King Khalid University Hospital, Riyadh 12372, Saudi Arabia
| | - G R Brindha
- School of Computing, SASTRA Deemed University, Tirumalaisamudram, Thanjavur 613401, Tamil Nadu, India
| | - N Rajendra Prasad
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalainagar 608002, Tamil Nadu, India.
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15
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Barbieri A, Thonghin N, Shafi T, Prince SM, Collins RF, Ford RC. Structure of ABCB1/P-glycoprotein bound to the CFTR potentiator ivacaftor.. [DOI: 10.1101/2021.06.11.448073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
AbstractABCB1 (P-glycoprotein) is an ATP binding cassette transporter that is involved in the clearance of xenobiotics and it affects the disposition of many drugs in the body. Here we have studied ABCB1 in the drug-bound and drug-free states, simultaneously, using high contrast cryo-electron microscopy imaging and a Volta phase plate. The binding of the potent CFTR potentiator, ivacaftor, at a site in the central aqueous cavity is mediated by transmembrane α-helices 3,6,10,11 & 12. Binding is associated with a wider separation of the two halves of the transporter in the inward-facing state. Induced-fit changes the nucleotide binding domains in a way that may explain their increased affinity for ATP when drug is bound. Comparison of ivacaftor-bound structures of CFTR and ABCB1 suggests common features in the binding modes.
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16
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Fleming TJ, Schrankel CS, Vyas H, Rosenblatt HD, Hamdoun A. CRISPR/Cas9 mutagenesis reveals a role for ABCB1 in gut immune responses to Vibrio diazotrophicus in sea urchin larvae. J Exp Biol 2021; 224:jeb232272. [PMID: 33653719 PMCID: PMC8077557 DOI: 10.1242/jeb.232272] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 02/08/2021] [Indexed: 12/16/2022]
Abstract
The ABC transporter ABCB1 plays an important role in the disposition of xenobiotics. Embryos of most species express high levels of this transporter in early development as a protective mechanism, but its native substrates are not known. Here, we used larvae of the sea urchin Strongylocentrotus purpuratus to characterize the early life expression and role of Sp-ABCB1a, a homolog of ABCB1. The results indicate that while Sp-ABCB1a is initially expressed ubiquitously, it becomes enriched in the developing gut. Using optimized CRISPR/Cas9 gene editing methods to achieve high editing efficiency in the F0 generation, we generated ABCB1a crispant embryos with significantly reduced transporter efflux activity. When infected with the opportunistic pathogen Vibrio diazotrophicus, Sp-ABCB1a crispant larvae demonstrated significantly stronger gut inflammation, immunocyte migration and cytokine Sp-IL-17 induction, as compared with infected control larvae. The results suggest an ancestral function of ABCB1 in host-microbial interactions, with implications for the survival of invertebrate larvae in the marine microbial environment.
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Affiliation(s)
- Travis J. Fleming
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
- Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115, USA
| | - Catherine S. Schrankel
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
| | - Himanshu Vyas
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
| | - Hannah D. Rosenblatt
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
| | - Amro Hamdoun
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
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17
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Matsuoka K, Nakatsu T, Kato H. The crystal structure of the CmABCB1 G132V mutant, which favors the outward-facing state, reveals the mechanism of the pivotal joint between TM1 and TM3. Protein Sci 2021; 30:1064-1071. [PMID: 33683740 DOI: 10.1002/pro.4058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 01/12/2023]
Abstract
CmABCB1 is a homologue of human P-glycoprotein, which extrudes various substrates by iterative cycles of conformational changes between the inward- and outward-facing states. Comparison of the inward- and outward-facing structures of CmABCB1 suggested that pivotal joints in the transmembrane domain regulate the tilt of transmembrane helices. Transmembrane helix 1 (TM1) forms a tight helix-helix contact with TM3 at the TM1-3 joint. Mutation of Gly132 to valine at the TM1-3 joint, G132V, caused a 10-fold increase in ATPase activity, but the mechanism underlying this change remains unclear. Here, we report a crystal structure of the outward-facing state of the CmABCB1 G132V mutant at a 2.15 Å resolution. We observed structural displacements between the outward-facing states of G132V and the previous one at the region around the TM1-3 joint, and a significant expansion at the extracellular gate. We hypothesize that steric hindrance caused by the Val substitution shifted the conformational equilibrium toward the outward-facing state, favoring the dimeric state of the nucleotide-binding domains and thereby increasing the ATPase activity of the G132V mutant.
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Affiliation(s)
- Keita Matsuoka
- Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Toru Nakatsu
- Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.,Advanced Photon Technology Division, RIKEN Harima Institute at SPring-8, Sayo-gun, Hyogo, Japan
| | - Hiroaki Kato
- Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.,Advanced Photon Technology Division, RIKEN Harima Institute at SPring-8, Sayo-gun, Hyogo, Japan
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18
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Zhang B, Kang Z, Zhang J, Kang Y, Liang L, Liu Y, Wang Q. Simultaneous binding mechanism of multiple substrates for multidrug resistance transporter P-glycoprotein. Phys Chem Chem Phys 2021; 23:4530-4543. [PMID: 33595579 DOI: 10.1039/d0cp05910b] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
P-glycoprotein (P-gp), a member of ATP-binding cassette (ABC) transporters, is a multidrug resistance pump. Its promiscuous nature is the main cause of multidrug resistance in cancer cells. P-gp can bind multiple drug molecules simultaneously; however, the binding mechanism is still not clear. Furthermore, the upper limit of the number of substrates that can be accommodated by the binding pocket is not fully understood. In this work, we explore the dynamic process of P-gp binding to multiple substrates by using molecular dynamics (MD) simulations. Our results show that P-gp possesses the ability for simultaneous binding, and that the number of substrates has an upper limit. The accommodating ability of P-gp relates to the size of the binding drugs, and conforms to induced fit theory. In the binding process, the residues 339PHE, 982MET and 986GLN are essential. The pocket of P-gp presents strong flexibility and adaptability features according to the mutation results in this work. Drug molecules tend to gather in the pocket during binding, and interactions between these molecules are beneficial to simultaneous binding. These findings provide new insights into the mechanism of the promiscuous nature of P-gp, and may give us a guideline for inhibiting the process of multidrug resistance.
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Affiliation(s)
- Bo Zhang
- Department of Chemistry and Soft Matter Research Center, Zhejiang University, Hangzhou 310027, People's Republic of China.
| | - Zhengzhong Kang
- Department of Chemistry and Soft Matter Research Center, Zhejiang University, Hangzhou 310027, People's Republic of China.
| | - Junqiao Zhang
- Department of Chemistry and Soft Matter Research Center, Zhejiang University, Hangzhou 310027, People's Republic of China.
| | - Yu Kang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Lijun Liang
- College of Life Information Science and Instrument Engineering, Hangzhou Dianzi University, Hangzhou, People's Republic of China
| | - Yingchun Liu
- Department of Chemistry and Soft Matter Research Center, Zhejiang University, Hangzhou 310027, People's Republic of China.
| | - Qi Wang
- Department of Chemistry and Soft Matter Research Center, Zhejiang University, Hangzhou 310027, People's Republic of China.
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19
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Lusvarghi S, Durell SR, Ambudkar SV. Does the ATP-bound EQ mutant reflect the pre- or post-ATP hydrolysis state in the catalytic cycle of human P-glycoprotein (ABCB1)? FEBS Lett 2021; 595:750-762. [PMID: 33547668 DOI: 10.1002/1873-3468.14054] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/14/2021] [Accepted: 01/28/2021] [Indexed: 12/15/2022]
Abstract
P-glycoprotein (P-gp, ABCB1) is an ABC transporter associated with the development of multidrug resistance to chemotherapy. During its catalytic cycle, P-gp undergoes significant conformational changes. Recently, atomic structures of some of these conformations have been resolved using cryo-electron microscopy. The ATP hydrolysis-defective mutant of the catalytic glutamate residue of the Walker B motif (E556Q/E1201Q) has been used to determine the structure of the ATP-bound inward-closed conformation of P-gp. Here, we show that this mutant does not appear to undergo the same steps as wild-type P-gp. We discuss conformational differences in the EQ mutant that may lead to a better understanding of the catalytic cycle of P-gp and propose that additional structural studies with wild-type P-gp are required.
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Affiliation(s)
- Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Stewart R Durell
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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20
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Mosca L, Ilari A, Fazi F, Assaraf YG, Colotti G. Taxanes in cancer treatment: Activity, chemoresistance and its overcoming. Drug Resist Updat 2021; 54:100742. [PMID: 33429249 DOI: 10.1016/j.drup.2020.100742] [Citation(s) in RCA: 121] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/12/2020] [Accepted: 11/16/2020] [Indexed: 02/07/2023]
Abstract
Since 1984, when paclitaxel was approved by the FDA for the treatment of advanced ovarian carcinoma, taxanes have been widely used as microtubule-targeting antitumor agents. However, their historic classification as antimitotics does not describe all their functions. Indeed, taxanes act in a complex manner, altering multiple cellular oncogenic processes including mitosis, angiogenesis, apoptosis, inflammatory response, and ROS production. On the one hand, identification of the diverse effects of taxanes on oncogenic signaling pathways provides opportunities to apply these cytotoxic drugs in a more rational manner. On the other hand, this may facilitate the development of novel treatment modalities to surmount anticancer drug resistance. In the latter respect, chemoresistance remains a major impediment which limits the efficacy of antitumor chemotherapy. Taxanes have shown impact on key molecular mechanisms including disruption of mitotic spindle, mitosis slippage and inhibition of angiogenesis. Furthermore, there is an emerging contribution of cellular processes including autophagy, oxidative stress, epigenetic alterations and microRNAs deregulation to the acquisition of taxane resistance. Hence, these two lines of findings are currently promoting a more rational and efficacious taxane application as well as development of novel molecular strategies to enhance the efficacy of taxane-based cancer treatment while overcoming drug resistance. This review provides a general and comprehensive picture on the use of taxanes in cancer treatment. In particular, we describe the history of application of taxanes in anticancer therapeutics, the synthesis of the different drugs belonging to this class of cytotoxic compounds, their features and the differences between them. We further dissect the molecular mechanisms of action of taxanes and the molecular basis underlying the onset of taxane resistance. We further delineate the possible modalities to overcome chemoresistance to taxanes, such as increasing drug solubility, delivery and pharmacokinetics, overcoming microtubule alterations or mitotic slippage, inhibiting drug efflux pumps or drug metabolism, targeting redox metabolism, immune response, and other cellular functions.
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Affiliation(s)
- Luciana Mosca
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, P. le A. Moro 5, 00185 Rome, Italy
| | - Andrea Ilari
- Institute of Molecular Biology and Pathology, Italian National Research Council (IBPM-CNR), c/o Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
| | - Francesco Fazi
- Dept. Anatomical, Histological, Forensic & Orthopedic Sciences, Section of Histology and Medical Embryology, Sapienza University, Via A. Scarpa 14-16, 00161 Rome, Italy
| | - Yehuda G Assaraf
- The Fred Wyszkowski Cancer Research Lab, Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Gianni Colotti
- Institute of Molecular Biology and Pathology, Italian National Research Council (IBPM-CNR), c/o Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
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21
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Abstract
Drug transporters are integral membrane proteins that play a critical role in drug disposition by affecting absorption, distribution, and excretion. They translocate drugs, as well as endogenous molecules and toxins, across membranes using ATP hydrolysis, or ion/concentration gradients. In general, drug transporters are expressed ubiquitously, but they function in drug disposition by being concentrated in tissues such as the intestine, the kidneys, the liver, and the brain. Based on their primary sequence and their mechanism, transporters can be divided into the ATP-binding cassette (ABC), solute-linked carrier (SLC), and the solute carrier organic anion (SLCO) superfamilies. Many X-ray crystallography and cryo-electron microscopy (cryo-EM) structures have been solved in the ABC and SLC transporter superfamilies or of their bacterial homologs. The structures have provided valuable insight into the structural basis of transport. This chapter will provide particular focus on the promiscuous drug transporters because of their effect on drug disposition and the challenges associated with them.
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Affiliation(s)
- Arthur G Roberts
- Pharmaceutical and Biomedical Sciences Department, University of Georgia, Athens, GA, USA.
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22
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Stockner T, Gradisch R, Schmitt L. The role of the degenerate nucleotide binding site in type I ABC exporters. FEBS Lett 2020; 594:3815-3838. [PMID: 33179257 PMCID: PMC7756269 DOI: 10.1002/1873-3468.13997] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/26/2020] [Accepted: 10/15/2020] [Indexed: 12/18/2022]
Abstract
ATP‐binding cassette (ABC) transporters are fascinating molecular machines that are capable of transporting a large variety of chemically diverse compounds. The energy required for translocation is derived from binding and hydrolysis of ATP. All ABC transporters share a basic architecture and are composed of two transmembrane domains and two nucleotide binding domains (NBDs). The latter harbor all conserved sequence motifs that hallmark the ABC transporter superfamily. The NBDs form the nucleotide binding sites (NBSs) in their interface. Transporters with two active NBSs are called canonical transporters, while ABC exporters from eukaryotic organisms, including humans, frequently have a degenerate NBS1 containing noncanonical residues that strongly impair ATP hydrolysis. Here, we summarize current knowledge on degenerate ABC transporters. By integrating structural information with biophysical and biochemical evidence of asymmetric function, we develop a model for the transport cycle of degenerate ABC transporters. We will elaborate on the unclear functional advantages of a degenerate NBS.
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Affiliation(s)
- Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Ralph Gradisch
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University, Düsseldorf, Germany
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