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Mitchell-White JI, Briggs DA, Mistry SJ, Mbiwan HA, Kellam B, Holliday ND, Briddon SJ, Kerr ID. A time-resolved Förster resonance energy transfer assay to investigate drug and inhibitor binding to ABCG2. Arch Biochem Biophys 2024; 753:109915. [PMID: 38307314 DOI: 10.1016/j.abb.2024.109915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/21/2023] [Accepted: 01/17/2024] [Indexed: 02/04/2024]
Abstract
The human ATP-binding cassette (ABC) transporter, ABCG2, is responsible for multidrug resistance in some tumours. Detailed knowledge of its activity is crucial for understanding drug transport and resistance in cancer, and has implications for wider pharmacokinetics. The binding of substrates and inhibitors is a key stage in the transport cycle of ABCG2. Here, we describe a novel binding assay using a high affinity fluorescent inhibitor based on Ko143 and time-resolved Förster resonance energy transfer (TR-FRET) to measure saturation binding to ABCG2. This binding is displaced by Ko143 and other known ABCG2 ligands, and is sensitive to the addition of AMP-PNP, a non-hydrolysable ATP analogue. This assay complements the arsenal of methods for determining drug:ABCG2 interactions and has the possibility of being adaptable for other multidrug pumps.
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Affiliation(s)
- James I Mitchell-White
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK; Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, The Midlands, UK.
| | - Deborah A Briggs
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Sarah J Mistry
- School of Pharmacy, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Hannah A Mbiwan
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK; School of Pharmacy, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Barrie Kellam
- School of Pharmacy, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Nicholas D Holliday
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Stephen J Briddon
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK; Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, The Midlands, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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2
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Tidy A, Abu Bakar N, Carrier D, Kerr ID, Hodgman C, Bennett MJ, Swarup R. Mechanistic insight into the role of AUXIN RESISTANCE4 in trafficking of AUXIN1 and LIKE AUX1-2. Plant Physiol 2023; 194:422-433. [PMID: 37776522 PMCID: PMC10756756 DOI: 10.1093/plphys/kiad506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/10/2023] [Accepted: 08/22/2023] [Indexed: 10/02/2023]
Abstract
AUXIN RESISTANCE4 (AXR4) regulates the trafficking of auxin influx carrier AUXIN1 (AUX1), a plasma-membrane protein that predominantly localizes to the endoplasmic reticulum (ER) in the absence of AXR4. In Arabidopsis (Arabidopsis thaliana), AUX1 is a member of a small multigene family comprising 4 highly conserved genes-AUX1, LIKE-AUX1 (LAX1), LAX2, and LAX3. We report here that LAX2 also requires AXR4 for correct localization to the plasma membrane. AXR4 is a plant-specific protein and contains a weakly conserved α/β hydrolase fold domain that is found in several classes of lipid hydrolases and transferases. We have previously proposed that AXR4 may either act as (i) a post-translational modifying enzyme through its α/β hydrolase fold domain or (ii) an ER accessory protein, which is a special class of ER protein that regulates targeting of their cognate partner proteins. Here, we show that AXR4 is unlikely to act as a post-translational modifying enzyme as mutations in several highly conserved amino acids in the α/β hydrolase fold domain can be tolerated and active site residues are missing. We also show that AUX1 and AXR4 physically interact with each other and that AXR4 reduces aggregation of AUX1 in a dose-dependent fashion. Our results suggest that AXR4 acts as an ER accessory protein. A better understanding of AXR4-mediated trafficking of auxin transporters in crop plants will be crucial for improving root traits (designer roots) for better acquisition of water and nutrients for sustainable and resilient agriculture.
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Affiliation(s)
- Alison Tidy
- Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK
| | - Norliza Abu Bakar
- Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK
| | - David Carrier
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Charlie Hodgman
- Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, UK
| | - Malcolm J Bennett
- Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, UK
| | - Ranjan Swarup
- Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, UK
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Jackson HK, Mitoko C, Linke F, Macarthur D, Kerr ID, Coyle B. Extracellular Vesicles Potentiate Medulloblastoma Metastasis in an EMMPRIN and MMP-2 Dependent Manner. Cancers (Basel) 2023; 15:cancers15092601. [PMID: 37174066 PMCID: PMC10177484 DOI: 10.3390/cancers15092601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/19/2023] [Accepted: 04/23/2023] [Indexed: 05/15/2023] Open
Abstract
Extracellular vesicles (EVs) have emerged as pivotal mediators of communication in the tumour microenvironment. More specifically, nanosized extracellular vesicles termed exosomes have been shown to contribute to the establishment of a premetastatic niche. Here, we sought to determine what role exosomes play in medulloblastoma (MB) progression and elucidate the underlying mechanisms. Metastatic MB cells (D458 and CHLA-01R) were found to secrete markedly more exosomes compared to their nonmetastatic, primary counterparts (D425 and CHLA-01). In addition, metastatic cell-derived exosomes significantly enhanced the migration and invasiveness of primary MB cells in transwell migration assays. Protease microarray analysis identified that matrix metalloproteinase-2 (MMP-2) was enriched in metastatic cells, and zymography and flow cytometry assays of metastatic exosomes demonstrated higher levels of functionally active MMP-2 on their external surface. Stable genetic knockdown of MMP-2 or extracellular matrix metalloproteinase inducer (EMMPRIN) in metastatic MB cells resulted in the loss of this promigratory effect. Analysis of serial patient cerebrospinal fluid (CSF) samples showed an increase in MMP-2 activity in three out of four patients as the tumour progressed. This study demonstrates the importance of EMMPRIN and MMP-2-associated exosomes in creating a favourable environment to drive medulloblastoma metastasis via extracellular matrix signalling.
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Affiliation(s)
- Hannah K Jackson
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University Park, University of Nottingham, Nottingham NG7 2RD, UK
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, UK
| | - Christine Mitoko
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University Park, University of Nottingham, Nottingham NG7 2RD, UK
| | - Franziska Linke
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University Park, University of Nottingham, Nottingham NG7 2RD, UK
- Department of Experimental Urology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands
| | - Donald Macarthur
- Department of Neurosurgery, Nottingham University Hospital, Nottingham NG7 2UH, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Beth Coyle
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University Park, University of Nottingham, Nottingham NG7 2RD, UK
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4
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Linke F, Johnson JEC, Kern S, Bennett CD, Lourdusamy A, Lea D, Clifford SC, Merry CLR, Stolnik S, Alexander MR, Peet AC, Scurr DJ, Griffiths RL, Grabowska AM, Kerr ID, Coyle B. Identifying new biomarkers of aggressive Group 3 and SHH medulloblastoma using 3D hydrogel models, single cell RNA sequencing and 3D OrbiSIMS imaging. Acta Neuropathol Commun 2023; 11:6. [PMID: 36631900 PMCID: PMC9835248 DOI: 10.1186/s40478-022-01496-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/19/2022] [Indexed: 01/13/2023] Open
Abstract
The most common malignant brain tumour in children, medulloblastoma (MB), is subdivided into four clinically relevant molecular subgroups, although targeted therapy options informed by understanding of different cellular features are lacking. Here, by comparing the most aggressive subgroup (Group 3) with the intermediate (SHH) subgroup, we identify crucial differences in tumour heterogeneity, including unique metabolism-driven subpopulations in Group 3 and matrix-producing subpopulations in SHH. To analyse tumour heterogeneity, we profiled individual tumour nodules at the cellular level in 3D MB hydrogel models, which recapitulate subgroup specific phenotypes, by single cell RNA sequencing (scRNAseq) and 3D OrbiTrap Secondary Ion Mass Spectrometry (3D OrbiSIMS) imaging. In addition to identifying known metabolites characteristic of MB, we observed intra- and internodular heterogeneity and identified subgroup-specific tumour subpopulations. We showed that extracellular matrix factors and adhesion pathways defined unique SHH subpopulations, and made up a distinct shell-like structure of sulphur-containing species, comprising a combination of small leucine-rich proteoglycans (SLRPs) including the collagen organiser lumican. In contrast, the Group 3 tumour model was characterized by multiple subpopulations with greatly enhanced oxidative phosphorylation and tricarboxylic acid (TCA) cycle activity. Extensive TCA cycle metabolite measurements revealed very high levels of succinate and fumarate with malate levels almost undetectable particularly in Group 3 tumour models. In patients, high fumarate levels (NMR spectroscopy) alongside activated stress response pathways and high Nuclear Factor Erythroid 2-Related Factor 2 (NRF2; gene expression analyses) were associated with poorer survival. Based on these findings we predicted and confirmed that NRF2 inhibition increased sensitivity to vincristine in a long-term 3D drug treatment assay of Group 3 MB. Thus, by combining scRNAseq and 3D OrbiSIMS in a relevant model system we were able to define MB subgroup heterogeneity at the single cell level and elucidate new druggable biomarkers for aggressive Group 3 and low-risk SHH MB.
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Affiliation(s)
- Franziska Linke
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - James E C Johnson
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Stefanie Kern
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | - Christopher D Bennett
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
- Birmingham Children's Hospital, Birmingham, UK
| | - Anbarasu Lourdusamy
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Daniel Lea
- Digital Research Service, University of Nottingham, Nottingham, UK
| | - Steven C Clifford
- Wolfson Childhood Cancer Research Centre, Translational & Clinical Research Institute, Newcastle University Centre for Cancer, Newcastle Upon Tyne, NE1 7RU, UK
| | - Catherine L R Merry
- School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Snow Stolnik
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | | | - Andrew C Peet
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
- Birmingham Children's Hospital, Birmingham, UK
| | - David J Scurr
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | | | - Anna M Grabowska
- School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Beth Coyle
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK.
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5
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Iqbal S, Flux C, Briggs DA, Deplazes E, Long J, Skrzypek R, Rothnie A, Kerr ID, Callaghan R. Vinca alkaloid binding to P-glycoprotein occurs in a processive manner. Biochim Biophys Acta Biomembr 2022; 1864:184005. [PMID: 35863425 DOI: 10.1016/j.bbamem.2022.184005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 07/08/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
A mechanistic understanding of how P-glycoprotein (Pgp) is able to bind and transport its astonishing range of substrates remains elusive. Pharmacological data demonstrated the presence of at least four distinct binding sites, but their locations have not been fully elucidated. The combination of biochemical and structural data suggests that initial binding may occur in the central cavity or at the lipid-protein interface. Our objective was to define the binding sites for two transported substrates of Pgp; the anticancer drug vinblastine and the fluorescent probe rhodamine 123. A series of mutations was generated in positions proximal to previously defined drug-interacting residues on Pgp. The protein was purified and reconstituted into styrene-maleic acid lipid particles (SMALPs) to measure the apparent drug binding constant or into liposomes for assessment of drug-stimulated ATP hydrolysis. The biochemical data were reconciled with structural models of Pgp using molecular docking. The data indicated that the binding of rhodamine 123 occurred predominantly within the central cavity of Pgp. In contrast, the significantly more hydrophobic vinblastine bound to both the lipid-protein interface and within the central cavity. The data suggest that the initial interaction of vinca alkaloids with Pgp occurs at the lipid interface followed by internalisation into the central cavity, which also provides the transport conduit. This model is supported by recent structural observations with Pgp and early biophysical and cross-linking approaches. Moreover, the proposed model illustrates that the broad substrate profile for Pgp is underpinned by a combination of multiple initial interaction sites and an accommodating transport conduit.
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Affiliation(s)
- Shagufta Iqbal
- Division of Biomedical Science & Biochemistry, Research School of Biology, The Australian National University, Canberra, Australia
| | - Caitlin Flux
- Division of Biomedical Science & Biochemistry, Research School of Biology, The Australian National University, Canberra, Australia
| | - Deborah A Briggs
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Evelyne Deplazes
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Australia
| | - Jiansi Long
- Division of Biomedical Science & Biochemistry, Research School of Biology, The Australian National University, Canberra, Australia
| | - Ruth Skrzypek
- Division of Biomedical Science & Biochemistry, Research School of Biology, The Australian National University, Canberra, Australia
| | - Alice Rothnie
- Health & Life Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Richard Callaghan
- Division of Biomedical Science & Biochemistry, Research School of Biology, The Australian National University, Canberra, Australia; School of Biomedical Sciences, Faculty of Biological Science, University of Leeds, Leeds, UK.
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6
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Broadbent L, Depping P, Lodé A, Vaitsopoulou A, Hardy D, Ayub H, Mitchell-White J, Kerr ID, Goddard AD, Bill RM, Rothnie AJ. Detergent-Free Membrane Protein Purification Using SMA Polymer. Methods Mol Biol 2022; 2507:389-404. [PMID: 35773594 DOI: 10.1007/978-1-0716-2368-8_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
One of the big challenges for the study of structure and function of membrane proteins is the need to extract them from the membrane. Traditionally this was achieved using detergents which disrupt the membrane and form a micelle around the protein, but this can cause issues with protein function and/or stability. In 2009 an alternative approach was reported, using styrene maleic acid (SMA) copolymer to extract small discs of lipid bilayer encapsulated by the polymer and termed SMALPs (SMA lipid particles). Since then this approach has been shown to work for a range of different proteins from many different expression systems. It allows the extraction and purification of a target protein while maintaining a lipid bilayer environment. Recently this has led to several new high-resolution structures and novel insights to function. As with any method there are some limitations and issues to be aware of. Here we describe a standard protocol for preparation of the polymer and its use for membrane protein purification, and also include details of typical challenges that may be encountered and possible ways to address those.
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Affiliation(s)
- Luke Broadbent
- College of Health & Life Sciences, Aston University, Birmingham, UK
| | - Peer Depping
- College of Health & Life Sciences, Aston University, Birmingham, UK
| | - Alexis Lodé
- College of Health & Life Sciences, Aston University, Birmingham, UK
| | | | - David Hardy
- College of Health & Life Sciences, Aston University, Birmingham, UK
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Hoor Ayub
- College of Health & Life Sciences, Aston University, Birmingham, UK
- Faculty of Health & Life Sciences, Coventry University, Coventry, UK
| | - James Mitchell-White
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, UK
| | - Alan D Goddard
- College of Health & Life Sciences, Aston University, Birmingham, UK
| | - Roslyn M Bill
- College of Health & Life Sciences, Aston University, Birmingham, UK
| | - Alice J Rothnie
- College of Health & Life Sciences, Aston University, Birmingham, UK.
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7
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Nasir A, Cardall A, Othman RT, Nicolaou N, Lourdusamy A, Linke F, Onion D, Ryzhova M, Cameron H, Valente C, Ritchie A, Korshunov A, Pfister SM, Grabowska AM, Kerr ID, Coyle B. ABCB1 inhibition provides a novel therapeutic target to block TWIST1-induced migration in medulloblastoma. Neurooncol Adv 2021; 3:vdab030. [PMID: 33948561 PMCID: PMC8080134 DOI: 10.1093/noajnl/vdab030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background Therapeutic intervention in metastatic medulloblastoma is dependent on elucidating the underlying metastatic mechanism. We investigated whether an epithelial–mesenchymal transition (EMT)-like pathway could drive medulloblastoma metastasis. Methods A 3D Basement Membrane Extract (3D-BME) model was used to investigate medulloblastoma cell migration. Cell line growth was quantified with AlamarBlue metabolic assays and the morphology assessed by time-lapse imaging. Gene expression was analyzed by qRT-PCR and protein expression by immunohistochemistry of patient tissue microarrays and mouse orthotopic xenografts. Chromatin immunoprecipitation was used to determine whether the EMT transcription factor TWIST1 bound to the promoter of the multidrug pump ABCB1. TWIST1 was overexpressed in MED6 cells by lentiviral transduction (MED6-TWIST1). Inhibition of ABCB1 was mediated by vardenafil, and TWIST1 expression was reduced by either Harmine or shRNA. Results Metastatic cells migrated to form large metabolically active aggregates, whereas non-tumorigenic/non-metastatic cells formed small aggregates with decreasing metabolic activity. TWIST1 expression was upregulated in the 3D-BME model. TWIST1 and ABCB1 were significantly associated with metastasis in patients (P = .041 and P = .04, respectively). High nuclear TWIST1 expression was observed in the invasive edge of the MED1 orthotopic model, and TWIST1 knockdown in cell lines was associated with reduced cell migration (P < .05). TWIST1 bound to the ABCB1 promoter (P = .03) and induced cell aggregation in metastatic and TWIST1-overexpressing, non-metastatic (MED6-TWIST1) cells, which was significantly attenuated by vardenafil (P < .05). Conclusions In this study, we identified a TWIST1–ABCB1 signaling axis during medulloblastoma migration, which can be therapeutically targeted with the clinically approved ABCB1 inhibitor, vardenafil.
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Affiliation(s)
- Aishah Nasir
- Children's Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Alice Cardall
- Children's Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Ramadhan T Othman
- Children's Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Niovi Nicolaou
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Anbarasu Lourdusamy
- Children's Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Franziska Linke
- Children's Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - David Onion
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Marina Ryzhova
- Department of Neuropathology, NN Burdenko Neurosurgical Institute, Moscow, Russia
| | - Hanna Cameron
- Children's Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Cara Valente
- Children's Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Alison Ritchie
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Andrey Korshunov
- Cooperation Unit Neuro-oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Stefan M Pfister
- Hopp Children's Cancer Center Heidelberg (KiTZ), German Cancer Research Center (DKFZ), Division of Pediatric Neurooncology and Heidelberg University Hospital, Department of Pediatric Hematology and Oncology, Heidelberg, Germany
| | - Anna M Grabowska
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Beth Coyle
- Children's Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
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8
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Vaughan-Hirsch J, Tallerday EJ, Burr CA, Hodgens C, Boeshore SL, Beaver K, Melling A, Sari K, Kerr ID, Šimura J, Ljung K, Xu D, Liang W, Bhosale R, Schaller GE, Bishopp A, Kieber JJ. Function of the pseudo phosphotransfer proteins has diverged between rice and Arabidopsis. Plant J 2021; 106:159-173. [PMID: 33421204 DOI: 10.1111/tpj.15156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 06/12/2023]
Abstract
The phytohormone cytokinin plays a significant role in nearly all aspects of plant growth and development. Cytokinin signaling has primarily been studied in the dicot model Arabidopsis, with relatively little work done in monocots, which include rice (Oryza sativa) and other cereals of agronomic importance. The cytokinin signaling pathway is a phosphorelay comprised of the histidine kinase receptors, the authentic histidine phosphotransfer proteins (AHPs) and type-B response regulators (RRs). Two negative regulators of cytokinin signaling have been identified: the type-A RRs, which are cytokinin primary response genes, and the pseudo histidine phosphotransfer proteins (PHPs), which lack the His residue required for phosphorelay. Here, we describe the role of the rice PHP genes. Phylogenic analysis indicates that the PHPs are generally first found in the genomes of gymnosperms and that they arose independently in monocots and dicots. Consistent with this, the three rice PHPs fail to complement an Arabidopsis php mutant (aphp1/ahp6). Disruption of the three rice PHPs results in a molecular phenotype consistent with these elements acting as negative regulators of cytokinin signaling, including the induction of a number of type-A RR and cytokinin oxidase genes. The triple php mutant affects multiple aspects of rice growth and development, including shoot morphology, panicle architecture, and seed fill. In contrast to Arabidopsis, disruption of the rice PHPs does not affect root vascular patterning, suggesting that while many aspects of key signaling networks are conserved between monocots and dicots, the roles of at least some cytokinin signaling elements are distinct.
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Affiliation(s)
| | - Emily J Tallerday
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Christian A Burr
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Charlie Hodgens
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Samantha L Boeshore
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Kevin Beaver
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Allison Melling
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Kartika Sari
- School of Biosciences, University of Nottingham, Loughborough, LE12 5RD, UK
- FKIP, Universitas Muhammadiyah Metro, Lampung, 34111, Indonesia
| | - Ian D Kerr
- University of Nottingham, Loughborough, NG7 2UH, UK
| | - Jan Šimura
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences (SLU), Umeå, 901 83, Sweden
| | - Karin Ljung
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences (SLU), Umeå, 901 83, Sweden
| | - Dawei Xu
- School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Wanqi Liang
- School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Rahul Bhosale
- School of Biosciences, University of Nottingham, Loughborough, LE12 5RD, UK
- Future Food Beacon of Excellence and School of Biosciences, University of Nottingham, LE12 5RD, UK
| | - G Eric Schaller
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
| | - Anthony Bishopp
- School of Biosciences, University of Nottingham, Loughborough, LE12 5RD, UK
| | - Joseph J Kieber
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
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9
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Nasir A, Cardall A, Othman RT, Nicolaou N, Lourdusamy A, Linke F, Onion D, Ryzhova M, Cameron H, Valente C, Ritchie A, Korshunov A, Pfister SM, Grabowska AM, Kerr ID, Coyle B. Corrigendum to: ABCB1 inhibition provides a novel therapeutic target to block TWIST1-induced migration in medulloblastoma. Neurooncol Adv 2021; 3:vdab155. [PMID: 34988447 PMCID: PMC8698731 DOI: 10.1093/noajnl/vdab155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Aishah Nasir
- Children’s Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Alice Cardall
- Children’s Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | | | - Niovi Nicolaou
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Anbarasu Lourdusamy
- Children’s Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Franziska Linke
- Children’s Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - David Onion
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Marina Ryzhova
- Department of Neuropathology, NN Burdenko Neurosurgical Institute, Moscow, Russia
| | - Hanna Cameron
- Children’s Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Cara Valente
- Children’s Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Alison Ritchie
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Andrey Korshunov
- Cooperation Unit Neuro-oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Stefan M Pfister
- Hopp Children’s Cancer Center Heidelberg (KiTZ), German Cancer Research Center (DKFZ), Division of Pediatric Neurooncology and Heidelberg University Hospital, Department of Pediatric Hematology and Oncology, Heidelberg, Germany
| | - Anna M Grabowska
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Beth Coyle
- Children’s Brain Tumour Research Centre, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, UK
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Linke F, Aldighieri M, Lourdusamy A, Grabowska AM, Stolnik S, Kerr ID, Merry CL, Coyle B. 3D hydrogels reveal medulloblastoma subgroup differences and identify extracellular matrix subtypes that predict patient outcome. J Pathol 2020; 253:326-338. [PMID: 33206391 PMCID: PMC7986745 DOI: 10.1002/path.5591] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 10/19/2020] [Accepted: 11/10/2020] [Indexed: 12/13/2022]
Abstract
Medulloblastoma (MB) is the most common malignant brain tumour in children and is subdivided into four subgroups: WNT, SHH, Group 3, and Group 4. These molecular subgroups differ in their metastasis patterns and related prognosis rates. Conventional 2D cell culture methods fail to recapitulate these clinical differences. Realistic 3D models of the cerebellum are therefore necessary to investigate subgroup‐specific functional differences and their role in metastasis and chemoresistance. A major component of the brain extracellular matrix (ECM) is the glycosaminoglycan hyaluronan. MB cell lines encapsulated in hyaluronan hydrogels grew as tumour nodules, with Group 3 and Group 4 cell lines displaying clinically characteristic laminar metastatic patterns and levels of chemoresistance. The glycoproteins, laminin and vitronectin, were identified as subgroup‐specific, tumour‐secreted ECM factors. Gels of higher complexity, formed by incorporation of laminin or vitronectin, revealed subgroup‐specific adhesion and growth patterns closely mimicking clinical phenotypes. ECM subtypes, defined by relative levels of laminin and vitronectin expression in patient tissue microarrays and gene expression data sets, were able to identify novel high‐risk MB patient subgroups and predict overall survival. Our hyaluronan model system has therefore allowed us to functionally characterize the interaction between different MB subtypes and their environment. It highlights the prognostic and pathological role of specific ECM factors and enables preclinical development of subgroup‐specific therapies. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Franziska Linke
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Macha Aldighieri
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Anbarasu Lourdusamy
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Anna M Grabowska
- Division of Cancer and Stem Cells, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Snow Stolnik
- Division of Molecular Therapeutics and Formulation, School of Pharmacy, University of Nottingham, Nottingham, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Catherine Lr Merry
- Division of Cancer and Stem Cells, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Beth Coyle
- Children's Brain Tumour Research Centre, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
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11
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Khunweeraphong N, Mitchell-White J, Szöllősi D, Hussein T, Kuchler K, Kerr ID, Stockner T, Lee JY. Picky ABCG5/G8 and promiscuous ABCG2 - a tale of fatty diets and drug toxicity. FEBS Lett 2020; 594:4035-4058. [PMID: 32978801 PMCID: PMC7756502 DOI: 10.1002/1873-3468.13938] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 09/03/2020] [Indexed: 12/20/2022]
Abstract
Structural data on ABCG5/G8 and ABCG2 reveal a unique molecular architecture for subfamily G ATP‐binding cassette (ABCG) transporters and disclose putative substrate‐binding sites. ABCG5/G8 and ABCG2 appear to use several unique structural motifs to execute transport, including the triple helical bundles, the membrane‐embedded polar relay, the re‐entry helices, and a hydrophobic valve. Interestingly, ABCG2 shows extreme substrate promiscuity, whereas ABCG5/G8 transports only sterol molecules. ABCG2 structures suggest a large internal cavity, serving as a binding region for substrates and inhibitors, while mutational and pharmacological analyses support the notion of multiple binding sites. By contrast, ABCG5/G8 shows a collapsed cavity of insufficient size to hold substrates. Indeed, mutational analyses indicate a sterol‐binding site at the hydrophobic interface between the transporter and the lipid bilayer. In this review, we highlight key differences and similarities between ABCG2 and ABCG5/G8 structures. We further discuss the relevance of distinct and shared structural features in the context of their physiological functions. Finally, we elaborate on how ABCG2 and ABCG5/G8 could pave the way for studies on other ABCG transporters.
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Affiliation(s)
- Narakorn Khunweeraphong
- Max Perutz Labs Vienna, Campus Vienna Biocenter, Center for Medical Biochemistry, Medical University of Vienna, Vienna, Austria.,CCRI-St. Anna Children's Cancer Research Institute, Vienna, Austria
| | - James Mitchell-White
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| | - Dániel Szöllősi
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Toka Hussein
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Karl Kuchler
- Max Perutz Labs Vienna, Campus Vienna Biocenter, Center for Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Ian D Kerr
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| | - Thomas Stockner
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Jyh-Yeuan Lee
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
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12
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Carey Hulyer AR, Briggs DA, O'Mara ML, Kerr ID, Harmer JR, Callaghan R. Cross-linking, DEER-spectroscopy and molecular dynamics confirm the inward facing state of P-glycoprotein in a lipid membrane. J Struct Biol 2020; 211:107513. [PMID: 32339763 DOI: 10.1016/j.jsb.2020.107513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 04/09/2020] [Accepted: 04/23/2020] [Indexed: 02/07/2023]
Abstract
The drug efflux pump P-glycoprotein (P-gp) displays a complex transport mechanism involving multiple drug binding sites and two centres for nucleotide hydrolysis. Elucidating the molecular mechanism of transport remains elusive and the availability of P-gp structures in distinct natural and ligand trapped conformations will accelerate our understanding. The present investigation sought to provide biochemical data to validate specific features of these structures; with particular focus on the transmembrane domain that provides the transport conduit. Hence our focus was on transmembrane helices six and twelve (TM6/TM12), which are believed to participate in drug binding, as they line the central transport conduit and provide a direct link to the catalytic centres. A series of P-gp mutants were generated with a single cysteine in both TM6 and TM12 to facilitate measurement of inter-helical distances using cross-linking and DEER strategies. Experimental results were compared to published structures per se and those refined by MD simulations. This analysis revealed that the refined inward-facing murine structure (4M1M) of P-gp provides a good representation of the proximity, topography and relative motions of TM6 and TM12 in reconstituted human P-gp.
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Affiliation(s)
- Alex R Carey Hulyer
- Research School of Biology, and the Medical School, Australian National University, Canberra, ACT 2601, Australia
| | - Deborah A Briggs
- Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Megan L O'Mara
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Ian D Kerr
- Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Jeffrey R Harmer
- The Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Richard Callaghan
- Research School of Biology, and the Medical School, Australian National University, Canberra, ACT 2601, Australia.
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13
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Horsey AJ, Briggs DA, Holliday ND, Briddon SJ, Kerr ID. Application of fluorescence correlation spectroscopy to study substrate binding in styrene maleic acid lipid copolymer encapsulated ABCG2. Biochim Biophys Acta Biomembr 2020; 1862:183218. [PMID: 32057756 PMCID: PMC7156912 DOI: 10.1016/j.bbamem.2020.183218] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/28/2020] [Accepted: 01/30/2020] [Indexed: 12/16/2022]
Abstract
ABCG2 is one of a trio of human ATP binding cassette transporters that have the ability to bind and transport a diverse array of chemical substrates out of cells. This so-called "multidrug" transport has numerous physiological consequences including effects on how drugs are absorbed into and eliminated from the body. Understanding how ABCG2 is able to interact with multiple drug substrates remains an important goal in transporter biology. Most drugs are believed to interact with ABCG2 through the hydrophobic lipid bilayer and experimental systems for ABCG2 study need to incorporate this. We have exploited styrene maleic acid to solubilise ABCG2 from HEK293T cells overexpressing the transporter, and confirmed by dynamic light scattering and fluorescence correlation spectroscopy (FCS) that this results in the extraction of SMA lipid copolymer (SMALP) particles that are uniform in size and contain a dimer of ABCG2, which is the predominant physiological state. FCS was further employed to measure the diffusion of a fluorescent ABCG2 substrate (BODIPY-prazosin) in the presence and absence of SMALP particles of purified ABCG2. Autocorrelation analysis of FCS traces enabled the mathematical separation of free BODIPY-prazosin from drug bound to ABCG2 and allowed us to show that combining SMALP extraction with FCS can be used to study specific drug: transporter interactions.
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Affiliation(s)
- Aaron J Horsey
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Deborah A Briggs
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Nicholas D Holliday
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Stephen J Briddon
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK; Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK.
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.
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14
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Kapoor P, Briggs DA, Cox MH, Kerr ID. Disruption of the Unique ABCG-Family NBD:NBD Interface Impacts Both Drug Transport and ATP Hydrolysis. Int J Mol Sci 2020; 21:ijms21030759. [PMID: 31979415 PMCID: PMC7037313 DOI: 10.3390/ijms21030759] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 01/13/2020] [Accepted: 01/21/2020] [Indexed: 01/03/2023] Open
Abstract
ABCG2 is one of a triumvirate of human multidrug ATP binding cassette (ABC) transporters that are implicated in the defense of cells and tissues against cytotoxic chemicals, but these transporters can also confer chemotherapy resistance states in oncology. Understanding the mechanism of ABCG2 is thus imperative if we are to be able to counter its deleterious activity. The structure of ABCG2 and its related family members (ABCG5/G8) demonstrated that there were two interfaces between the nucleotide binding domains (NBD). In addition to the canonical ATP “sandwich-dimer” interface, there was a second contact region between residues at the C-terminus of the NBD. We investigated this second interface by making mutations to a series of residues that are in close interaction with the opposite NBD. Mutated ABCG2 isoforms were expressed in human embryonic kidney (HEK) 293T cells and analysed for targeting to the membrane, drug transport, and ATPase activity. Mutations to this second interface had a number of effects on ABCG2, including altered drug specificity, altered drug transport, and, in two mutants, a loss of ATPase activity. The results demonstrate that this region is particularly sensitive to mutation and can impact not only direct, local NBD events (i.e., ATP hydrolysis) but also the allosteric communication to the transmembrane domains and drug transport.
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15
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Sabnis DH, Storer LCD, Liu JF, Jackson HK, Kilday JP, Grundy RG, Kerr ID, Coyle B. A role for ABCB1 in prognosis, invasion and drug resistance in ependymoma. Sci Rep 2019; 9:10290. [PMID: 31311995 PMCID: PMC6635358 DOI: 10.1038/s41598-019-46700-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 06/27/2019] [Indexed: 11/16/2022] Open
Abstract
Three of the hallmarks of poor prognosis in paediatric ependymoma are drug resistance, local invasion and recurrence. We hypothesised that these hallmarks were due to the presence of a sub-population of cancer stem cells expressing the multi-drug efflux transporter ABCB1. ABCB1 gene expression was observed in 4 out of 5 paediatric ependymoma cell lines and increased in stem cell enriched neurospheres. Functional inhibition of ABCB1 using vardenafil or verapamil significantly (p ≤ 0.05–0.001) potentiated the response to three chemotherapeutic drugs (vincristine, etoposide and methotrexate). Both inhibitors were also able to significantly reduce migration (p ≤ 0.001) and invasion (p ≤ 0.001). We demonstrate that ABCB1 positive patients from an infant chemotherapy-led trial (CNS9204) had a shorter mean event free survival (EFS) (2.7 versus 8.6 years; p = 0.007 log-rank analysis) and overall survival (OS) (5.4 versus 12 years; p = 0.009 log-rank analysis). ABCB1 positivity also correlated with reduced event free survival in patients with incompletely resected tumours who received chemotherapy across CNS9204 and CNS9904 (a radiotherapy-led SIOP 1999-04 trial cohort; p = 0.03). ABCB1 is a predictive marker of chemotherapy response in ependymoma patients and vardenafil, currently used to treat paediatric pulmonary hypertension in children, could be repurposed to reduce chemoresistance, migration and invasion in paediatric ependymoma patients at non-toxic concentrations.
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Affiliation(s)
- Durgagauri H Sabnis
- Children's Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Lisa C D Storer
- Children's Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Jo-Fen Liu
- Children's Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Hannah K Jackson
- Children's Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - J P Kilday
- Royal Manchester Children's Hospital, Children's Brain Tumour Research Network & Institute of Cancer Sciences, The University of Manchester, Manchester, UK
| | - Richard G Grundy
- Children's Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Beth Coyle
- Children's Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK.
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16
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Heyes N, Kapoor P, Kerr ID. Polymorphisms of the Multidrug Pump ABCG2: A Systematic Review of Their Effect on Protein Expression, Function, and Drug Pharmacokinetics. Drug Metab Dispos 2018; 46:1886-1899. [PMID: 30266733 DOI: 10.1124/dmd.118.083030] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/20/2018] [Indexed: 12/11/2022] Open
Abstract
The widespread expression and polyspecificity of the multidrug ABCG2 efflux transporter make it an important determinant of the pharmacokinetics of a variety of substrate drugs. Null ABCG2 expression has been linked to the Junior blood group. Polymorphisms affecting the expression or function of ABCG2 may have clinically important roles in drug disposition and efficacy. The most well-studied single nucleotide polymorphism (SNP), Q141K (421C>A), is shown to decrease ABCG2 expression and activity, resulting in increased total drug exposure and decreased resistance to various substrates. The effect of Q141K can be rationalized by inspection of the ABCG2 structure, and the effects of this SNP on protein processing may make it a target for pharmacological intervention. The V12M SNP (34G>A) appears to improve outcomes in cancer patients treated with tyrosine kinase inhibitors, but the reasons for this are yet to be established, and this residue's role in the mechanism of the protein is unexplored by current biochemical and structural approaches. Research into the less-common polymorphisms is confined to in vitro studies, with several polymorphisms shown to decrease resistance to anticancer agents such as SN-38 and mitoxantrone. In this review, we present a systematic analysis of the effects of ABCG2 polymorphisms on ABCG2 function and drug pharmacokinetics. Where possible, we use recent structural advances to present a molecular interpretation of the effects of SNPs and indicate where we need further in vitro experiments to fully resolve how SNPs impact ABCG2 function.
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Affiliation(s)
- Niall Heyes
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Parth Kapoor
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Ian D Kerr
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom
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17
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Linke F, Merry CLR, Grabowska AM, Stolnik-Trenkic S, Kerr ID, Coyle B. MBRS-43. MODELLING MEDULLOBLASTOMA INVASION AND CHEMORESISTANCE IN A 3D HYALURONAN HYDROGEL SYSTEM. Neuro Oncol 2018. [DOI: 10.1093/neuonc/noy059.488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Franziska Linke
- Children’s Brain Tumour Research Centre, School of Medicine; University of Nottingham, Nottingham, UK
| | - Catherine L R Merry
- Division of Cancer & Stem Cells, School of Medicine; University of Nottingham, Nottingham, UK
| | - Anna M Grabowska
- Division of Cancer & Stem Cells, School of Medicine; University of Nottingham, Nottingham, UK
| | - Snow Stolnik-Trenkic
- Division of Molecular Therapeutics and Formulation, School of Pharmacy; University of Nottingham, Nottingham, UK
| | - Ian D Kerr
- Division of Cell Signalling & Pharmacology, School of Life Sciences; University of Nottingham, Nottingham, UK
| | - Beth Coyle
- Children’s Brain Tumour Research Centre, School of Medicine; University of Nottingham, Nottingham, UK
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18
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Jackson HK, Linke F, Kerr ID, Coyle B. MBRS-21. EXTRACELLULAR VESICLES FROM METASTATIC MEDULLOBLASTOMA CELL LINES CARRY mRNAs KNOWN TO CORRELATE WITH METASTATIC DISEASE. Neuro Oncol 2018. [DOI: 10.1093/neuonc/noy059.466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Hannah K Jackson
- Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Franziska Linke
- Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Ian D Kerr
- Division of Cell Signalling & Pharmacology, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Beth Coyle
- Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
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Aldighieri M, Linke F, Grabowska AM, Kerr ID, Coyle B. MBRS-44. MODELLING THE BRAIN/CSF INTERFACE IN MEDULLOBLASTOMA. Neuro Oncol 2018. [DOI: 10.1093/neuonc/noy059.489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Macha Aldighieri
- Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Franziska Linke
- Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Anna M Grabowska
- Division of Cancer & Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Ian D Kerr
- Division of Cell Signalling & Pharmacology, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Beth Coyle
- Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
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20
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Cardall A, Nasir A, Linke F, Grabowska AM, Kerr ID, Coyle B. MBRS-39. TWIST1 PLAYS A REGULATORY ROLE IN MEDULLOBLASTOMA METASTASIS. Neuro Oncol 2018. [DOI: 10.1093/neuonc/noy059.484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Alice Cardall
- Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Aishah Nasir
- Division of Cancer & Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Franziska Linke
- Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Anna M Grabowska
- Division of Cancer & Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Ian D Kerr
- Division of Cell Signalling & Pharmacology, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Beth Coyle
- Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
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Mittra R, Pavy M, Subramanian N, George AM, O'Mara ML, Kerr ID, Callaghan R. Location of contact residues in pharmacologically distinct drug binding sites on P-glycoprotein. Biochem Pharmacol 2017; 123:19-28. [DOI: 10.1016/j.bcp.2016.10.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/06/2016] [Indexed: 10/20/2022]
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22
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Nasir A, Othman RT, Ivanov DP, Storer L, Onion D, Korshunov A, Pfister SM, Kerr ID, Grabowska A, Coyle B. MB-92DO ABCB1 EXPRESSING DRUG RESISTANT CANCER STEM CELLS UNDERLIE MEDULLOBLASTOMA METASTASIS? Neuro Oncol 2016. [DOI: 10.1093/neuonc/now076.88] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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23
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Wong K, Briddon SJ, Holliday ND, Kerr ID. Plasma membrane dynamics and tetrameric organisation of ABCG2 transporters in mammalian cells revealed by single particle imaging techniques. Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 2016; 1863:19-29. [DOI: 10.1016/j.bbamcr.2015.10.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/17/2015] [Accepted: 10/06/2015] [Indexed: 10/22/2022]
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Nasir A, Othman RT, Storer L, Onion D, Lourdusamy A, Kerr ID, Grabowska A, Coyle B. OP63METASTATIC MEDULLOBLASTOMA - ARE DRUG RESISTANT CANCER STEM CELLS TWIST1NG AWAY? Neuro Oncol 2015. [DOI: 10.1093/neuonc/nov284.56] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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25
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Darby RAJ, Unsworth A, Knapp S, Kerr ID, Callaghan R. Overcoming ABCG2-mediated drug resistance with imidazo-[1,2-b]-pyridazine-based Pim1 kinase inhibitors. Cancer Chemother Pharmacol 2015; 76:853-64. [PMID: 26351135 DOI: 10.1007/s00280-015-2858-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/25/2015] [Indexed: 01/16/2023]
Abstract
PURPOSE Multidrug efflux pumps such as ABCG2 confer drug resistance to a number of cancer types, leading to poor prognosis and outcome. To date, the strategy of directly inhibiting multidrug efflux pumps in order to overcome drug resistance in cancer has been unsuccessful. An alternative strategy is to target proteins involved in the regulation of multidrug efflux pump activity or expression. Pim1 kinase has been demonstrated to phosphorylate ABCG2, promote its oligomerisation and contribute to its ability to confer drug resistance. METHODS In the present manuscript, imidazo-pyridazine-based inhibitors of Pim1 were examined for their ability to overcome ABCG2-mediated drug resistance. Drug efficacy was measured as a cytotoxic response or an effect on transport by ABCG2. Protein expression patterns were assessed using western immuno-blotting. RESULTS The two Pim1 inhibitors increased the potency of flavopiridol, mitoxantrone, topotecan and doxorubicin, specifically in ABCG2-expressing cells. This effect was associated with an increase in the cellular accumulation of [(3)H]-mitoxantrone, suggesting direct impairment of the transporter. However, prolonged pre-incubation with the studied inhibitors greatly enhanced the effect on mitoxantrone accumulation. The inhibitors caused a significant time-dependent reduction in the expression of ABCG2 in the resistant cells, an effect that would improve drug efficacy. CONCLUSION Consequently, it appears that the Pim1 inhibitors display a dual-mode effect on ABCG2-expressing cancer cells. This may provide a powerful new strategy in overcoming drug resistance by targeting proteins that regulate expression of efflux pumps.
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Affiliation(s)
- Richard A J Darby
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Headington, UK
- Structural Genomics Consortium and Target Discovery Institute, University of Oxford, Old Road Campus, NDM Research Building, Oxford, OX3 7FZ, UK
| | - Amanda Unsworth
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Headington, UK
| | - Stefan Knapp
- Structural Genomics Consortium and Target Discovery Institute, University of Oxford, Old Road Campus, NDM Research Building, Oxford, OX3 7FZ, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Richard Callaghan
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Headington, UK.
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia.
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, McGrath JC, Catterall WA, Spedding M, Peters JA, Harmar AJ, Abul-Hasn N, Anderson CM, Anderson CMH, Araiksinen MS, Arita M, Arthofer E, Barker EL, Barratt C, Barnes NM, Bathgate R, Beart PM, Belelli D, Bennett AJ, Birdsall NJM, Boison D, Bonner TI, Brailsford L, Bröer S, Brown P, Calo G, Carter WG, Catterall WA, Chan SLF, Chao MV, Chiang N, Christopoulos A, Chun JJ, Cidlowski J, Clapham DE, Cockcroft S, Connor MA, Cox HM, Cuthbert A, Dautzenberg FM, Davenport AP, Dawson PA, Dent G, Dijksterhuis JP, Dollery CT, Dolphin AC, Donowitz M, Dubocovich ML, Eiden L, Eidne K, Evans BA, Fabbro D, Fahlke C, Farndale R, Fitzgerald GA, Fong TM, Fowler CJ, Fry JR, Funk CD, Futerman AH, Ganapathy V, Gaisnier B, Gershengorn MA, Goldin A, Goldman ID, Gundlach AL, Hagenbuch B, Hales TG, Hammond JR, Hamon M, Hancox JC, Hauger RL, Hay DL, Hobbs AJ, Hollenberg MD, Holliday ND, Hoyer D, Hynes NA, Inui KI, Ishii S, Jacobson KA, Jarvis GE, Jarvis MF, Jensen R, Jones CE, Jones RL, Kaibuchi K, Kanai Y, Kennedy C, Kerr ID, Khan AA, Klienz MJ, Kukkonen JP, Lapoint JY, Leurs R, Lingueglia E, Lippiat J, Lolait SJ, Lummis SCR, Lynch JW, MacEwan D, Maguire JJ, Marshall IL, May JM, McArdle CA, McGrath JC, Michel MC, Millar NS, Miller LJ, Mitolo V, Monk PN, Moore PK, Moorhouse AJ, Mouillac B, Murphy PM, Neubig RR, Neumaier J, Niesler B, Obaidat A, Offermanns S, Ohlstein E, Panaro MA, Parsons S, Pwrtwee RG, Petersen J, Pin JP, Poyner DR, Prigent S, Prossnitz ER, Pyne NJ, Pyne S, Quigley JG, Ramachandran R, Richelson EL, Roberts RE, Roskoski R, Ross RA, Roth M, Rudnick G, Ryan RM, Said SI, Schild L, Sanger GJ, Scholich K, Schousboe A, Schulte G, Schulz S, Serhan CN, Sexton PM, Sibley DR, Siegel JM, Singh G, Sitsapesan R, Smart TG, Smith DM, Soga T, Stahl A, Stewart G, Stoddart LA, Summers RJ, Thorens B, Thwaites DT, Toll L, Traynor JR, Usdin TB, Vandenberg RJ, Villalon C, Vore M, Waldman SA, Ward DT, Willars GB, Wonnacott SJ, Wright E, Ye RD, Yonezawa A, Zimmermann M. The Concise Guide to PHARMACOLOGY 2013/14: overview. Br J Pharmacol 2014; 170:1449-58. [PMID: 24528237 DOI: 10.1111/bph.12444] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties from the IUPHAR database. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. This compilation of the major pharmacological targets is divided into seven areas of focus: G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors & Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and GRAC and provides a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen P H Alexander
- School of Life Sciences, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
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Kerr ID, Nix P, Wenstrup RJ. Response to Cragun et al. Clin Genet 2014; 88:200. [PMID: 25256678 DOI: 10.1111/cge.12510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 09/23/2014] [Indexed: 11/30/2022]
Affiliation(s)
- I D Kerr
- Myriad Genetic Laboratories, Inc., Salt Lake City, UT, USA
| | - P Nix
- Myriad Genetic Laboratories, Inc., Salt Lake City, UT, USA
| | - R J Wenstrup
- Myriad Genetic Laboratories, Inc., Salt Lake City, UT, USA
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van Wonderen JH, McMahon RM, O'Mara ML, McDevitt CA, Thomson AJ, Kerr ID, MacMillan F, Callaghan R. The central cavity of ABCB1 undergoes alternating access during ATP hydrolysis. FEBS J 2014; 281:2190-2201. [PMID: 24597976 DOI: 10.1111/febs.12773] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 02/18/2014] [Accepted: 02/28/2014] [Indexed: 02/06/2023]
Abstract
Understanding the process that underlies multidrug recognition and efflux by P-glycoprotein (ABCB1) remains a key biological challenge. Structural data have recently become available for the murine and Caenorhabditis elegans homologues of ABCB1; however all structures were obtained in the absence of nucleotide. A feature of these structures was the presence of a central cavity that is inaccessible from the extracellular face of the protein. To determine the conformational dynamics of this region several residues in transmembrane helices TM6 (331, 343 and 354) and TM12 (980) were mutated to cysteine. Based upon structural predictions, these residues are proposed to line, or reside proximal to, the central cavity. The mutant isoforms were labelled with a paramagnetic probe enabling the application of EPR spectroscopic methods. Power saturation EPR spectra were recorded in the presence of hydrophobic (O2 ) or hydrophilic (NiEDDA) quenching agents to study the local environment of each residue. ABCB1 was trapped in both its nucleotide-bound and post-hydrolytic conformations and EPR spectra were again recorded in the presence and absence of quenching agents. The EPR line shapes provide information on the movements of these residues within TM6 and TM12 during ATP hydrolysis. Rationalization of the data with molecular dynamic simulations indicates that the cavity is converted to a configuration open to the aqueous phase following nucleotide binding, thereby suggesting alternating access to the cavity on opposite sides of the membrane during translocation.
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Affiliation(s)
- Jessica H van Wonderen
- Henry Wellcome Unit for Biological EPR, School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK
| | - Róisin M McMahon
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK.,Institute for Molecular Bioscience, Chemistry and Structural Biology Division, University of Queensland 4072, Australia
| | - Megan L O'Mara
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Christopher A McDevitt
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
| | - Andrew J Thomson
- Henry Wellcome Unit for Biological EPR, School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK
| | - Ian D Kerr
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH.UK
| | - Fraser MacMillan
- Henry Wellcome Unit for Biological EPR, School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK
| | - Richard Callaghan
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK.,Division of Biomedical Science & Biochemistry, Research School of Biology, College of Medicine, Biology & Environment, The Australian National University, Canberra ACT 0200 Australia
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Wong K, Ma J, Rothnie A, Biggin PC, Kerr ID. Towards understanding promiscuity in multidrug efflux pumps. Trends Biochem Sci 2013; 39:8-16. [PMID: 24316304 DOI: 10.1016/j.tibs.2013.11.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 10/31/2013] [Accepted: 11/05/2013] [Indexed: 10/25/2022]
Abstract
Drug export from cells is a major factor in the acquisition of cellular resistance to antimicrobial and cancer chemotherapy, and poses a significant threat to future clinical management of disease. Many of the proteins that catalyse drug efflux do so with remarkably low substrate specificity, a phenomenon known as multidrug transport. For these reasons we need a greater understanding of drug recognition and transport in multidrug pumps to inform research that attempts to circumvent their action. Structural and computational studies have been heralded as being great strides towards a full elucidation of multidrug recognition and transport. In this review we summarise these advances and ask how close we are to a molecular understanding of this remarkable phenomenon.
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Affiliation(s)
- Kelvin Wong
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Jerome Ma
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Alice Rothnie
- Life & Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Philip C Biggin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Ian D Kerr
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, NG7 2UH, UK.
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Pollock NL, McDevitt CA, Collins R, Niesten PHM, Prince S, Kerr ID, Ford RC, Callaghan R. Improving the stability and function of purified ABCB1 and ABCA4: the influence of membrane lipids. Biochim Biophys Acta 2013; 1838:134-47. [PMID: 24036079 DOI: 10.1016/j.bbamem.2013.09.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 08/27/2013] [Accepted: 09/03/2013] [Indexed: 12/17/2022]
Abstract
ATP Binding Cassette (ABC) transporters play prominent roles in numerous cellular processes and many have been implicated in human diseases. Unfortunately, detailed mechanistic information on the majority of ABC transporters has not yet been elucidated. The slow rate of progress of molecular and high resolution structural studies may be attributed to the difficulty in the investigation of integral membrane proteins. These difficulties include the expression of functional, non-aggregated protein in heterologous systems. Furthermore, the extraction of membrane proteins from source material remains a major bottle-neck in the process since there are relatively few guidelines for selection of an appropriate detergent to achieve optimal extraction. Whilst affinity tag strategies have simplified the purification of membrane proteins; many challenges remain. For example, the chromatographic process and associated steps can rapidly lead to functional inactivation, random aggregation, or even precipitation of the target protein. Furthermore, optimisation of high yield and purity, does not guarantee successful structure determination. Based on this series of potential issues, any investigation into structure-function of membrane proteins requires a systematic evaluation of preparation quality. In particular, the evaluation should focus on function, homogeneity and mono-dispersity. The present investigation provides a detailed assessment of the quality of purified ATP Binding Cassette (ABC) transporters; namely ABCB1 (P-gp) and ABCA4 (ABCR). A number of suggestions are provided to facilitate the production of functional, homogeneous and mono-disperse preparations using the insect cell expression system. Finally, the ABCA4 samples have been used to provide structural insights into this essential photo-receptor cell protein.
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Affiliation(s)
- Naomi L Pollock
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
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Kay C, Lawler K, Self TJ, Dyall SD, Kerr ID. Localisation of a family of complex-forming β-barrels in theT. vaginalishydrogenosomal membrane. FEBS Lett 2012; 586:4038-45. [DOI: 10.1016/j.febslet.2012.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 10/01/2012] [Accepted: 10/01/2012] [Indexed: 10/27/2022]
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Kay C, Woodward KD, Lawler K, Self TJ, Dyall SD, Kerr ID. The ATP-binding cassette proteins of the deep-branching protozoan parasite Trichomonas vaginalis. PLoS Negl Trop Dis 2012; 6:e1693. [PMID: 22724033 PMCID: PMC3378599 DOI: 10.1371/journal.pntd.0001693] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 03/18/2012] [Indexed: 02/06/2023] Open
Abstract
The ATP binding cassette (ABC) proteins are a family of membrane transporters and regulatory proteins responsible for diverse and critical cellular process in all organisms. To date, there has been no attempt to investigate this class of proteins in the infectious parasite Trichomonas vaginalis. We have utilized a combination of bioinformatics, gene sequence analysis, gene expression and confocal microscopy to investigate the ABC proteins of T. vaginalis. We demonstrate that, uniquely among eukaryotes, T. vaginalis possesses no intact full-length ABC transporters and has undergone a dramatic expansion of some ABC protein sub-families. Furthermore, we provide preliminary evidence that T. vaginalis is able to read through in-frame stop codons to express ABC transporter components from gene pairs in a head-to-tail orientation. Finally, with confocal microscopy we demonstrate the expression and endoplasmic reticulum localization of a number of T. vaginalis ABC transporters. The parasite Trichomonas vaginalis infects in excess of 100 million people per year, and is a contributory factor to enhanced transmission rates of HIV, the causative virus in AIDS. As such, T. vaginalis infection is an important public health concern. Understanding the biology of the organism is important to determine aspects of the response to drug treatment, host:parasite interactions and so on. We have investigated an important family of proteins – the ATP binding cassette transporters – which are present in the membranes of all cells, and which contribute to a diverse spectrum of important cellular processes. The ABC transporters of T. vaginalis were identified by analysis of primary amino acid sequence data, and examined by subsequent protein and gene expression studies. Our most important conclusion is that – uniquely amongst eukaryotes - T. vaginalis has no ABC transporters capable of acting as monomers. In other words, its ABC transporters must all act by forming functional complexes with other ABC proteins. This has implications for our understanding not just of the parasite's biology, but also its evolution. In summary our analysis opens up the path for future research of individual members of the ABC protein family in T. vaginalis.
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Affiliation(s)
- Christopher Kay
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - Katharine D. Woodward
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - Karen Lawler
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - Tim J. Self
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - Sabrina D. Dyall
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
- Department of Biosciences, University of Mauritius, Reduit, Mauritius
| | - Ian D. Kerr
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
- * E-mail:
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Abstract
Along with many other mammalian ATP-binding cassette (ABC) transporters, members of the ABCG group are involved in the regulated transport of hydrophobic compounds across cellular membranes. In humans, five ABCG family members have been identified, encoding proteins ranging from 638 to 678 amino acids in length. All five have been the subject of intensive investigation to better understand their physiological roles, expression patterns, interactions with substrates and inhibitors, and regulation at both the transcript and protein level. The principal substrates for at least four of the ABCG proteins are endogenous and dietary lipids, with ABCG1 implicated in particular in the export of cholesterol, and ABCG5 and G8 forming a functional heterodimer responsible for plant sterol elimination from the body. ABCG2 has a much broader substrate specificity and its ability to transport numerous diverse pharmaceuticals has implications for the absorption, distribution, metabolism, excretion and toxicity (ADMETOx) profile of these compounds. ABCG2 is one of at least three so-called multidrug resistant ABC transporters expressed in humans, and its activity is associated with decreased efficacy of anti-cancer agents in several carcinomas. In addition to its role in cancer, ABCG2 also plays a role in the normal physiological transport of urate and haem, the implications of which are described. We summarize here data on all five human ABCG transporters and provide a current perspective on their roles in human health and disease.
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Affiliation(s)
- Ian D Kerr
- School of Biomedical Sciences, Queen's Medical Centre, University of Nottingham, Nottingham.
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34
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Haider AJ, Briggs D, Self TJ, Chilvers HL, Holliday ND, Kerr ID. Dimerization of ABCG2 analysed by bimolecular fluorescence complementation. PLoS One 2011; 6:e25818. [PMID: 21991363 PMCID: PMC3185054 DOI: 10.1371/journal.pone.0025818] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 09/11/2011] [Indexed: 12/18/2022] Open
Abstract
ABCG2 is one of three human ATP binding cassette transporters that are functionally capable of exporting a diverse range of substrates from cells. The physiological consequence of ABCG2 multidrug transport activity in leukaemia, and some solid tumours is the acquisition of cancer multidrug resistance. ABCG2 has a primary structure that infers that a minimal functional transporting unit would be a homodimer. Here we investigated the ability of a bimolecular fluorescence complementation approach to examine ABCG2 dimers, and to probe the role of individual amino acid substitutions in dimer formation. ABCG2 was tagged with fragments of venus fluorescent protein (vYFP), and this tagging did not perturb trafficking or function. Co-expression of two proteins bearing N-terminal and C-terminal fragments of YFP resulted in their association and detection of dimerization by fluorescence microscopy and flow cytometry. Point mutations in ABCG2 which may affect dimer formation were examined for alterations in the magnitude of fluorescence complementation signal. Bimolecular fluorescence complementation (BiFC) demonstrated specific ABCG2 dimer formation, but no changes in dimer formation, resulting from single amino acid substitutions, were detected by BiFC analysis.
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Affiliation(s)
- Ameena J. Haider
- School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Deborah Briggs
- School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Tim J. Self
- School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Hannah L. Chilvers
- School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Nicholas D. Holliday
- School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Ian D. Kerr
- School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom
- * E-mail:
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Dorrian JM, Briggs DA, Ridley ML, Layfield R, Kerr ID. Induction of a stress response in Lactococcus lactis is associated with a resistance to ribosomally active antibiotics. FEBS J 2011; 278:4015-24. [DOI: 10.1111/j.1742-4658.2011.08305.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hussein D, Punjaruk W, Storer LCD, Shaw L, Othman R, Ottoman R, Peet A, Miller S, Bandopadhyay G, Heath R, Kumari R, Bowman KJ, Braker P, Rahman R, Jones GDD, Watson S, Lowe J, Kerr ID, Grundy RG, Coyle B. Pediatric brain tumor cancer stem cells: cell cycle dynamics, DNA repair, and etoposide extrusion. Neuro Oncol 2010; 13:70-83. [PMID: 20978004 PMCID: PMC3018909 DOI: 10.1093/neuonc/noq144] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Reliable model systems are needed to elucidate the role cancer stem cells (CSCs) play in pediatric brain tumor drug resistance. The majority of studies to date have focused on clinically distinct adult tumors and restricted tumor types. Here, the CSC component of 7 newly established primary pediatric cell lines (2 ependymomas, 2 medulloblastomas, 2 gliomas, and a CNS primitive neuroectodermal tumor) was thoroughly characterized. Comparison of DNA copy number with the original corresponding tumor demonstrated that genomic changes present in the original tumor, typical of that particular tumor type, were retained in culture. In each case, the CSC component was approximately 3–4-fold enriched in neurosphere culture compared with monolayer culture, and a higher capacity for multilineage differentiation was observed for neurosphere-derived cells. DNA content profiles of neurosphere-derived cells expressing the CSC marker nestin demonstrated the presence of cells in all phases of the cell cycle, indicating that not all CSCs are quiescent. Furthermore, neurosphere-derived cells demonstrated an increased resistance to etoposide compared with monolayer-derived cells, having lower initial DNA damage, potentially due to a combination of increased drug extrusion by ATP-binding cassette multidrug transporters and enhanced rates of DNA repair. Finally, orthotopic xenograft models reflecting the tumor of origin were established from these cell lines. In summary, these cell lines and the approach taken provide a robust model system that can be used to develop our understanding of the biology of CSCs in pediatric brain tumors and other cancer types and to preclinically test therapeutic agents.
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Affiliation(s)
- Deema Hussein
- Children's Brain Tumour Research Centre, School of Clinical Sciences, University of Nottingham, CBTRC, D32 Medical School, QMC, Clifton Boulevard, Nottingham NG7 2UH, UK
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Crowley E, O’Mara ML, Kerr ID, Callaghan R. Transmembrane helix 12 plays a pivotal role in coupling energy provision and drug binding in ABCB1. FEBS J 2010; 277:3974-85. [DOI: 10.1111/j.1742-4658.2010.07789.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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39
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McKerrow JH, Doyle PS, Engel JC, Podust LM, Robertson SA, Ferreira R, Saxton T, Arkin M, Kerr ID, Brinen LS, Craik CS. Two approaches to discovering and developing new drugs for Chagas disease. Mem Inst Oswaldo Cruz 2010; 104 Suppl 1:263-9. [PMID: 19753483 DOI: 10.1590/s0074-02762009000900034] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 06/09/2009] [Indexed: 11/21/2022] Open
Abstract
This review will focus on two general approaches carried out at the Sandler Center, University of California, San Francisco, to address the challenge of developing new drugs for the treatment of Chagas disease. The first approach is target-based drug discovery, and two specific targets, cytochrome P450 CYP51 and cruzain (aka cruzipain), are discussed. A 'proof of concept' molecule, the vinyl sulfone inhibitor K777, is now a clinical candidate. The preclinical assessment compliance for filing as an Investigational New Drug with the United States Food and Drug Administration (FDA) is presented, and an outline of potential clinical trials is given. The second approach to identifying new drug leads is parasite phenotypic screens in culture. The development of an assay allowing high throughput screening of Trypanosoma cruzi amastigotes in skeletal muscle cells is presented. This screen has the advantage of not requiring specific strains of parasites, so it could be used with field isolates, drug resistant strains or laboratory strains. It is optimized for robotic liquid handling and has been validated through a screen of a library of FDA-approved drugs identifying 65 hits.
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Affiliation(s)
- J H McKerrow
- Sandler Center at Mission Bay, University of California, San Francisco, CA 94158-2330, USA.
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Kerr ID, Jones PM, George AM. Multidrug efflux pumps: the structures of prokaryotic ATP-binding cassette transporter efflux pumps and implications for our understanding of eukaryotic P-glycoproteins and homologues. FEBS J 2009; 277:550-63. [PMID: 19961540 DOI: 10.1111/j.1742-4658.2009.07486.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
One of the Holy Grails of ATP-binding cassette transporter research is a structural understanding of drug binding and transport in a eukaryotic multidrug resistance pump. These transporters are front-line mediators of drug resistance in cancers and represent an important therapeutic target in future chemotherapy. Although there has been intensive biochemical research into the human multidrug pumps, their 3D structure at atomic resolution remains unknown. The recent determination of the structure of a mouse P-glycoprotein at subatomic resolution is complemented by structures for a number of prokaryotic homologues. These structures have provided advances into our knowledge of the ATP-binding cassette exporter structure and mechanism, and have provided the template data for a number of homology modelling studies designed to reconcile biochemical data on these clinically important proteins.
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Affiliation(s)
- Ian D Kerr
- School of Biomedical Sciences, University of Nottingham, Nottingham, UK.
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Crowley E, O'Mara ML, Reynolds C, Tieleman DP, Storm J, Kerr ID, Callaghan R. Transmembrane helix 12 modulates progression of the ATP catalytic cycle in ABCB1. Biochemistry 2009; 48:6249-58. [PMID: 19456124 DOI: 10.1021/bi900373x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Multidrug efflux pumps, such as P-glycoprotein (ABCB1), present major barriers to the success of chemotherapy in a number of clinical settings. Molecular details of the multidrug efflux process by ABCB1 remain elusive, in particular, the interdomain communication associated with bioenergetic coupling. The present investigation has focused on the role of transmembrane helix 12 (TM12) in the multidrug efflux process of ABCB1. Cysteine residues were introduced at various positions within TM12, and their effect on ATPase activity, nucleotide binding, and drug interaction were assessed. Mutation of several residues within TM12 perturbed the maximal ATPase activity of ABCB1, and the underlying cause was a reduction in basal (i.e., drug-free) hydrolysis of the nucleotide. Two of the mutations (L976C and F978C) were found to reduce the binding of [gamma-(32)P]-azido-ATP to ABCB1. In contrast, the A980C mutation within TM12 enhanced the rate of ATP hydrolysis; once again, this was due to modified basal activity. Several residues also caused reductions in the potency of stimulation of ATP hydrolysis by nicardipine and vinblastine, although the effects were independent of changes in drug binding per se. Overall, the results indicate that TM12 plays a key role in the progression of the ATP hydrolytic cycle in ABCB1, even in the absence of the transported substrate.
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Affiliation(s)
- Emily Crowley
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom
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42
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Abstract
ABCG2 is best known as a multidrug transporter capable of conferring resistance to cancer cells. However, the protein is also inherently expressed in numerous barrier tissues and intriguingly within hematopoietic stem cells. Unlike its partners ABCB1 and ABCC1, there is considerably less information available on the molecular mechanism of ABCG2. The transporter has a distinct topology and is presumed to function as a homodimer. However, a number of biochemical studies have presented data to suggest that the protein adopts higher order oligomers. This review focuses on this controversial issue with particular reference to findings from low resolution structural data. In addition, a number of molecular models of ABCG2 based on high resolution structures of bacterial ABC transporters have recently become available and are critically assessed. ABCG2 is a structurally distinct member of the triumvirate of human multidrug transporters and continues to evade description of a unifying molecular mechanism.
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Affiliation(s)
- Christopher A McDevitt
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, United Kingdom
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43
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Chuthapisith S, Bean BE, Cowley G, Eremin JM, Samphao S, Layfield R, Kerr ID, Wiseman J, El-Sheemy M, Sreenivasan T, Eremin O. Annexins in human breast cancer: Possible predictors of pathological response to neoadjuvant chemotherapy. Eur J Cancer 2009; 45:1274-1281. [PMID: 19171478 DOI: 10.1016/j.ejca.2008.12.026] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 12/17/2008] [Accepted: 12/19/2008] [Indexed: 11/24/2022]
Abstract
Neoadjuvant chemotherapy is used in women who have large or locally advanced breast cancers. However, up to 70% of women who receive neoadjuvant chemotherapy fail to achieve a complete pathological response in their primary tumour (a surrogate marker of long-term survival). Five proteins, previously identified to be linked with chemoresistance in our in vitro experiments, were identified histochemically in pre-treatment core needle biopsies from 40 women with large or locally advanced breast cancers. Immunohistochemical staining with the five proteins showed no single protein to be a predictor of response to chemotherapy. However, pre-treatment breast cancer specimens that were annexin-A2 positive but annexin-A1 negative correlated with a poor pathological response (p=0.04, Fisher's exact test). The mechanisms by which annexins confer chemoresistance have not been identified, but may be due to inhibition of apoptosis. Annexin-A1 has been shown to enhance apoptosis, whilst annexin-A2, by contrast, inhibits apoptosis.
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Affiliation(s)
- Suebwong Chuthapisith
- Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; Division of Surgery, Queen's Medical Centre, University of Nottingham, E Floor, West Block, Nottingham NG7 2UH, UK.
| | | | | | | | - Srila Samphao
- Lincoln Breast Unit, Lincoln County Hospital, Lincoln, UK
| | - Robert Layfield
- School of Biomedical Sciences, Queen's Medical Centre, University of Nottingham, UK
| | - Ian D Kerr
- School of Biomedical Sciences, Queen's Medical Centre, University of Nottingham, UK
| | - Janice Wiseman
- Lincoln Breast Unit, Lincoln County Hospital, Lincoln, UK
| | | | | | - Oleg Eremin
- Division of Surgery, Queen's Medical Centre, University of Nottingham, E Floor, West Block, Nottingham NG7 2UH, UK; Lincoln Breast Unit, Lincoln County Hospital, Lincoln, UK
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44
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Carrier DJ, Bakar NTA, Swarup R, Callaghan R, Napier RM, Bennett MJ, Kerr ID. The binding of auxin to the Arabidopsis auxin influx transporter AUX1. Plant Physiol 2008; 148:529-35. [PMID: 18614710 PMCID: PMC2528085 DOI: 10.1104/pp.108.122044] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 06/24/2008] [Indexed: 05/20/2023]
Abstract
The cellular import of the hormone auxin is a fundamental requirement for the generation of auxin gradients that control a multitude of plant developmental processes. The AUX/LAX family of auxin importers, exemplified by AUX1 from Arabidopsis (Arabidopsis thaliana), has been shown to mediate auxin import when expressed heterologously. The quantitative nature of the interaction between AUX1 and its transport substrate indole-3-acetic acid (IAA) is incompletely understood, and we sought to address this in the present investigation. We expressed AUX1 to high levels in a baculovirus expression system and prepared membrane fragments from baculovirus-infected insect cells. These membranes proved suitable for determination of the binding of IAA to AUX1 and enabled us to determine a K(d) of 2.6 mum, comparable with estimates for the K(m) for IAA transport. The efficacy of a number of auxin analogues and auxin transport inhibitors to displace IAA binding from AUX1 has also been determined and can be rationalized in terms of their physiological effects. Determination of the parameters describing the initial interaction between a plant transporter and its hormone ligand provides novel quantitative data for modeling auxin fluxes.
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Affiliation(s)
- David J Carrier
- School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom
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45
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McDevitt CA, Crowley E, Hobbs G, Starr KJ, Kerr ID, Callaghan R. Is ATP binding responsible for initiating drug translocation by the multidrug transporter ABCG2? FEBS J 2008; 275:4354-62. [PMID: 18657189 DOI: 10.1111/j.1742-4658.2008.06578.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
ABCG2 confers resistance to cancer cells by mediating the ATP-dependent outward efflux of chemotherapeutic compounds. Recent studies have indicated that the protein contains a number of interconnected drug binding sites. The present investigation examines the coupling of drug binding to ATP hydrolysis. Initial drug binding to the protein requires a high-affinity interaction with the drug binding site, followed by transition and reorientation to the low-affinity state to enable dissociation at the extracellular face. [3H]Daunomycin binding to the ABCG2 R482G isoform was examined in the nucleotide-bound and post-hydrolytic conformations. Binding of [3H]daunomycin was displaced by ATP analogues, indicating transition to a low-affinity conformation prior to hydrolysis. The low-affinity state was observed to be retained immediately post-hydrolysis. Therefore, the dissociation of phosphate and/or ADP is likely to be responsible for resetting of the transporter. The data indicate that, like ABCB1 and ABCC1, the 'power stroke' for translocation in ABCG2 R482G is the binding of nucleotide.
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Affiliation(s)
- Christopher A McDevitt
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, UK
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46
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Storm J, Modok S, O’Mara ML, Tieleman DP, Kerr ID, Callaghan R. Cytosolic Region of TM6 in P-Glycoprotein: Topographical Analysis and Functional Perturbation by Site Directed Labeling. Biochemistry 2008; 47:3615-24. [DOI: 10.1021/bi7023089] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Janet Storm
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, United Kingdom, Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada, and Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, United Kingdom
| | - Szabolcs Modok
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, United Kingdom, Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada, and Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, United Kingdom
| | - Megan L. O’Mara
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, United Kingdom, Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada, and Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, United Kingdom
| | - D. Peter Tieleman
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, United Kingdom, Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada, and Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, United Kingdom
| | - Ian D. Kerr
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, United Kingdom, Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada, and Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, United Kingdom
| | - Richard Callaghan
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, United Kingdom, Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada, and Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, United Kingdom
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Abstract
Expression of the ABC transporter P-glycoprotein (P-gp or ABCB1) is associated with resistance to chemotherapy in cancer. However, early investigations into the regulation of ABCB1 expression revealed that the process is not a classical induction as observed for certain metabolizing enzymes. The process involves the cellular stress response pathway initiated by either inflicted (e.g., chemotherapy damage) or endogenous (e.g., hypoxia) factors. However, ABCB1 is also expressed in a number of noncancerous tissues. In particular, the protein is found at tissues providing a barrier or secretory function. The localization of ABCB1 in normal tissues will impact significantly on drug pharmacokinetics, in particular the absorption and elimination processes. This review also describes the mechanism underlying ABCB1 expression in noncancerous tissue, a process that does not involve the stress response.
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Affiliation(s)
- Richard Callaghan
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford, UK.
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48
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Lawson J, O'Mara ML, Kerr ID. Structure-based interpretation of the mutagenesis database for the nucleotide binding domains of P-glycoprotein. Biochim Biophys Acta 2007; 1778:376-91. [PMID: 18035039 DOI: 10.1016/j.bbamem.2007.10.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 10/12/2007] [Accepted: 10/25/2007] [Indexed: 12/15/2022]
Abstract
P-glycoprotein (P-gp) is the most intensively studied eukaryotic ATP binding cassette (ABC) transporter, due to its involvement in the multidrug resistance phenotype of a number of cancers. In common with most ABC transporters, P-gp is comprised of two transmembrane domains (TMDs) and two nucleotide binding domains (NBD), the latter coupling ATP hydrolysis with substrate transport (efflux in the case of P-gp). Biochemical investigations over the past twenty years have attempted to unlock mechanistic aspects of P-glycoprotein through scanning and site-directed mutagenesis of both the TMDs and the NBDs. Contemporaneously, crystallographers have elucidated the atomic structure of numerous ABC transporter NBDs, as well as the intact structure (i.e. NBDs and TMDs) of a distantly related ABC-exporter Sav1866. Significantly, the structure of P-gp remains unknown, and only low resolution electron microscopy data exists. Within the current manuscript we employ crystallographic data for homologous proteins, and a molecular model for P-gp, to perform a structural interpretation of the existing "mutagenesis database" for P-gp NBDs. Consequently, this will enable testable predictions to be made that will result in further in-roads into our understanding of this clinically important drug pump.
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Affiliation(s)
- J Lawson
- School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
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Storm J, O'Mara ML, Crowley EH, Peall J, Tieleman DP, Kerr ID, Callaghan R. Residue G346 in transmembrane segment six is involved in inter-domain communication in P-glycoprotein. Biochemistry 2007; 46:9899-910. [PMID: 17696319 DOI: 10.1021/bi700447p] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Multidrug transporters such as P-glycoprotein require considerable inter-domain communication to couple energy utilization with substrate translocation. Elucidation of the regions or residues involved in these communication pathways is a key step in the eventual molecular description of multidrug transport. We used cysteine-scanning mutagenesis to probe the functional involvement of residues along the cytoplasmic half of transmembrane segment 6 (TM6) and its extension toward the nucleotide binding domain. The mutation of one residue (G346C) in this segment adversely affected drug transport in cells. Further investigation using purified protein revealed that the underlying biochemical effect was a reduction in basal ATP hydrolysis. This G346C mutation also affected the stimulation of ATPase activity in a drug dependent manner but had no effect on drug binding, ATP binding, or ADP release. Homology modeling of P-glycoprotein indicated that the G346C mutation caused a steric interaction between TM5 and TM6, thereby precluding a helical movement required to support ATP hydrolysis.
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Affiliation(s)
- Janet Storm
- Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom
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50
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Chuthapisith S, Layfield R, Kerr ID, Hughes C, Eremin O. Proteomic profiling of MCF-7 breast cancer cells with chemoresistance to different types of anti-cancer drugs. Int J Oncol 2007; 30:1545-51. [PMID: 17487377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
Chemoresistance is a poor prognostic factor in breast cancer and, thus, presents a significant clinical challenge. The mechanisms of chemoresistance involve multiple complex biological processes. This study aims to identify common contributory factors to chemoresistance in breast cancer by comparing protein expression profiles of chemosensitive MCF-7 breast cancer cells and cells resistant to two different commonly used anti-cancer drugs (adriamycin and paclitaxel). Expression of the ATP binding cassette transporter, P-glycoprotein (P-gp), in breast tumours has previously been found to correlate with poor prognosis in vivo and, accordingly, we confirmed overexpression of P-gp in both adriamycin- and paclitaxel-resistant MCF-7 cells. Using two-dimensional gel electrophoresis and MALDI-TOF peptide mass fingerprinting, we identified 20 proteins differentially expressed between chemosensitive, adriamycin-resistant and paclitaxel-resistant MCF-7 cells. Cytokeratin-8, keratin-19, Hsp-27, 14-3-3 epsilon, annexin-A2 and phosphoglycerate kinase-1 showed altered expression in both adriamycin- and paclitaxel-resistant cells. Validation of a number of these changes was confirmed by Western blotting. Our findings provide further insights into the complex mechanisms of chemoresistance, as well as representing an attractive starting point for the identification of potential protein biomarkers to predict response to chemotherapy in breast cancer in vivo.
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