1
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Błauż A, Wachulec M, Rychlik B. Oncostatin M reverses ABCG2-mediated mitoxantrone resistance. Biomed Pharmacother 2024; 176:116861. [PMID: 38850649 DOI: 10.1016/j.biopha.2024.116861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/21/2024] [Accepted: 06/03/2024] [Indexed: 06/10/2024] Open
Abstract
Mitoxantrone resistant variant of SW620 line was developed, characterized and subsequently used as a model system to determine oncostatin M ability to modulate MDR phenomenon. The selection regimen allowed for overexpression of ABCG2 and ABCB1 both at the RNA and protein level, which was further confirmed by functional assays. Oncostatin M supplementation resulted in partial reversal of MDR phenotype by decreasing overexpression of ABCG2 demonstrating for the first time the ability of this cytokine for selective down-regulation of one of MDR proteins.
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Affiliation(s)
- Andrzej Błauż
- Cytometry Laboratory, Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, Poland.
| | - Marcin Wachulec
- Cytometry Laboratory, Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, Poland
| | - Błażej Rychlik
- Cytometry Laboratory, Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, Poland
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2
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Zechner M, Castro Jaramillo CA, Zubler NS, Taddio MF, Mu L, Altmann KH, Krämer SD. In Vitro and In Vivo Evaluation of ABCG2 (BCRP) Inhibitors Derived from Ko143. J Med Chem 2023; 66:6782-6797. [PMID: 37154765 DOI: 10.1021/acs.jmedchem.3c00168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Breast cancer resistance protein (BCRP, ABCG2) is an efflux transporter that plays a crucial role in multidrug resistance to antineoplastic drugs. Ko143, an analogue of the natural product fumitremorgin C, is a potent inhibitor of ABCG2 but is rapidly hydrolyzed to an inactive metabolite in vivo. To identify ABCG2 inhibitors with improved metabolic stability, we have assessed a series of Ko143 analogues for their ability to inhibit ABCG2-mediated transport in ABCG2-transduced MDCK II cells and determined the stability of the most potent compounds in liver microsomes. The most promising analogues were evaluated in vivo by positron emission tomography. In vitro, three of the tested analogues were potent ABCG2 inhibitors and stable in microsomes. In vivo, they increased the distribution of the ABCG2/ABCB1 substrate [11C]tariquidar to the brain both in wild-type (with Abcb1a/b transport blocked by tariquidar) and Abcb1a/b(-/-) mice. One analogue was more potent than Ko143 in both animal models.
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Affiliation(s)
- Melanie Zechner
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Claudia A Castro Jaramillo
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Nadine S Zubler
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Marco F Taddio
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Linjing Mu
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
- Department of Nuclear Medicine, University Hospital Zurich, CH-8091 Zurich, Switzerland
| | - Karl-Heinz Altmann
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Stefanie D Krämer
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
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3
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Gyöngy Z, Mocsár G, Hegedűs É, Stockner T, Ritter Z, Homolya L, Schamberger A, Orbán TI, Remenyik J, Szakacs G, Goda K. Nucleotide binding is the critical regulator of ABCG2 conformational transitions. eLife 2023; 12:83976. [PMID: 36763413 PMCID: PMC9917445 DOI: 10.7554/elife.83976] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 01/27/2023] [Indexed: 02/11/2023] Open
Abstract
ABCG2 is an exporter-type ABC protein that can expel numerous chemically unrelated xeno- and endobiotics from cells. When expressed in tumor cells or tumor stem cells, ABCG2 confers multidrug resistance, contributing to the failure of chemotherapy. Molecular details orchestrating substrate translocation and ATP hydrolysis remain elusive. Here, we present methods to concomitantly investigate substrate and nucleotide binding by ABCG2 in cells. Using the conformation-sensitive antibody 5D3, we show that the switch from the inward-facing (IF) to the outward-facing (OF) conformation of ABCG2 is induced by nucleotide binding. IF-OF transition is facilitated by substrates, and hindered by the inhibitor Ko143. Direct measurements of 5D3 and substrate binding to ABCG2 indicate that the high-to-low affinity switch of the drug binding site coincides with the transition from the IF to the OF conformation. Low substrate binding persists in the post-hydrolysis state, supporting that dissociation of the ATP hydrolysis products is required to reset the high substrate affinity IF conformation of ABCG2.
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Affiliation(s)
- Zsuzsanna Gyöngy
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of DebrecenDebrecenHungary,Doctoral School of Molecular Cell and Immune Biology, University of DebrecenDebrecenHungary
| | - Gábor Mocsár
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of DebrecenDebrecenHungary
| | - Éva Hegedűs
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of DebrecenDebrecenHungary
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of ViennaViennaAustria
| | - Zsuzsanna Ritter
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of DebrecenDebrecenHungary,Doctoral School of Molecular Cell and Immune Biology, University of DebrecenDebrecenHungary
| | - László Homolya
- Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
| | - Anita Schamberger
- Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
| | - Tamás I Orbán
- Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
| | - Judit Remenyik
- Institute of Food Technology, Faculty of Agricultural and Food Sciences and Environmental Management, University of DebrecenDebrecenHungary
| | - Gergely Szakacs
- Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary,Institute of Cancer Research, Medical University of ViennaViennaAustria
| | - Katalin Goda
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of DebrecenDebrecenHungary
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4
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Grigoreva TA, Vorona SV, Novikova DS, Tribulovich VG. Analysis of P-Glycoprotein Transport Cycle Reveals a New Way to Identify Efflux Inhibitors. ACS OMEGA 2022; 7:42835-42844. [PMID: 36467933 PMCID: PMC9713869 DOI: 10.1021/acsomega.2c04768] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 10/28/2022] [Indexed: 06/17/2023]
Abstract
P-glycoprotein (P-gp) is found to be of considerable interest for the design of drugs capable of treating chemoresistant tumors. This transporter is an interesting target for which an efficient approach has not yet been developed in terms of computer simulation. In this work, we use a combination of docking, molecular dynamics, and metadynamics to fully explore the states that occur during the capture of a ligand and subsequent efflux by P-gp. The proposed approach allowed us to substantiate a number of experimentally established facts, as well as to develop a new criterion for identifying potential P-gp inhibitors.
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5
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Ahmad S, Hassan MI, Gupta D, Dwivedi N, Islam A. Design and evaluation of pyrimidine derivatives as potent inhibitors of ABCG2, a breast cancer resistance protein. 3 Biotech 2022; 12:182. [PMID: 35875174 PMCID: PMC9296744 DOI: 10.1007/s13205-022-03231-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 06/18/2022] [Indexed: 11/25/2022] Open
Abstract
The protein ATP-binding cassette subfamily G member 2 (ABCG2) is one of the major factors behind multidrug resistance (MDR) in breast cancer. We performed three-dimensional quantitative structure-activity relationship (3D-QSAR) modelling, docking, and molecular dynamics (MD) simulation to design pyrimidine-based ABCG2 antagonists. The developed QSAR model (r 2 = 0.92, q 2 = 0.82, and good cross-validated r 2 = 0.73) dictate requirement of electrostatic, and hydrophobic fields for modulating bioactivity. Based on this rationale, we designed and screened 1010 new compounds, among them 2 (ND-510 and ND-500) exhibit excellent drug-like features. Comparative molecular docking, MM/GBSA and ADMET profiles were determined to understand the interactive poses, affinity, and drug-likeness of the designed compounds. Furthermore, MD simulations were performed with the ABCG2 receptor, and the results were compared with the two earlier synthesized active compounds. The outcomes of the study will help researchers to develop new antagonists for treatment of MDR breast cancer. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-022-03231-1.
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Affiliation(s)
- Shahnawaz Ahmad
- School of Biotechnology, College of Engineering and Technology, IFTM University, Lodhipur-Rajput, Delhi Road (NH-24), Moradabad, Uttar Pradesh 244102 India
| | - Md. Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, 110025 India
| | - Dinesh Gupta
- Translational Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067 India
| | - Neeraj Dwivedi
- School of Biotechnology, College of Engineering and Technology, IFTM University, Lodhipur-Rajput, Delhi Road (NH-24), Moradabad, Uttar Pradesh 244102 India
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, 110025 India
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6
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Interaction of crown ethers with the ABCG2 transporter and their implication for multidrug resistance reversal. Histochem Cell Biol 2022; 158:261-277. [PMID: 35648291 DOI: 10.1007/s00418-022-02106-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2022] [Indexed: 02/03/2023]
Abstract
Overexpression of ABC transporters, such as ABCB1 and ABCG2, plays an important role in mediating multidrug resistance (MDR) in cancer. This feature is also attributed to a subpopulation of cancer stem cells (CSCs), having enhanced tumourigenic potential. ABCG2 is specifically associated with the CSC phenotype, making it a valuable target for eliminating aggressive and resistant cells. Several natural and synthetic ionophores have been discovered as CSC-selective drugs that may also have MDR-reversing ability, whereas their interaction with ABCG2 has not yet been explored. We previously reported the biological activities, including ABCB1 inhibition, of a group of adamantane-substituted diaza-18-crown-6 (DAC) compounds that possess ionophore capabilities. In this study, we investigated the mechanism of ABCG2-inhibitory activity of DAC compounds and the natural ionophores salinomycin, monensin and nigericin. We used a series of functional assays, including real-time microscopic analysis of ABCG2-mediated fluorescent substrate transport in cells, and docking studies to provide comparative aspects for the transporter-compound interactions and their role in restoring chemosensitivity. We found that natural ionophores did not inhibit ABCG2, suggesting that their CSC selectivity is likely mediated by other mechanisms. In contrast, DACs with amide linkage in the side arms demonstrated noteworthy ABCG2-inhibitory activity, with DAC-3Amide proving to be the most potent. This compound induced conformational changes of the transporter and likely binds to both Cavity 1 and the NBD-TMD interface. DAC-3Amide reversed ABCG2-mediated MDR in model cells, without affecting ABCG2 expression or localization. These results pave the way for the development of new crown ether compounds with improved ABCG2-inhibitory properties.
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7
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Targeting breast cancer resistance protein (BCRP/ABCG2): Functional inhibitors and expression modulators. Eur J Med Chem 2022; 237:114346. [DOI: 10.1016/j.ejmech.2022.114346] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 03/15/2022] [Accepted: 04/01/2022] [Indexed: 12/16/2022]
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8
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Ibrahim MAA, Badr EAA, Abdelrahman AHM, Almansour NM, Shawky AM, Mekhemer GAH, Alrumaihi F, Moustafa MF, Atia MAM. Prospective Drug Candidates as Human Multidrug Transporter ABCG2 Inhibitors: an In Silico Drug Discovery Study. Cell Biochem Biophys 2021; 79:189-200. [PMID: 33954893 DOI: 10.1007/s12013-021-00985-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2021] [Indexed: 12/22/2022]
Abstract
Breast cancer resistance protein (ABCG2) is a human ATP-binding cassette (ABC) that plays a paramount role in multidrug resistance (MDR) in cancer therapy. The discovery of ABCG2 inhibitors could assist in designing unprecedented therapeutic strategies for cancer treatment. There is as yet no approved drug targeting ABCG2, although a large number of drug candidates have been clinically investigated. In this work, binding affinities of 181 drug candidates in clinical-trial or investigational stages as ABCG2 inhibitors were inspected using in silico techniques. Based on available experimental data, the performance of AutoDock4.2.6 software was first validated to predict the inhibitor-ABCG2 binding mode and affinity. Combined molecular docking calculations and molecular dynamics (MD) simulations, followed by molecular mechanics-generalized Born surface area (MM-GBSA) binding energy calculations, were then performed to filter out the studied drug candidates. From the estimated docking scores and MM-GBSA binding energies, six auspicious drug candidates-namely, pibrentasvir, venetoclax, ledipasvir, avatrombopag, cobicistat, and revefenacin-exhibited auspicious binding energies with value < -70.0 kcal/mol. Interestingly, pibrentasvir, venetoclax, and ledipasvir were observed to show even higher binding affinities with the ABCG2 transporter with binding energies of < -80.0 kcal/mol over long MD simulations of 100 ns. The stabilities of these three promising candidates in complex with ABCG2 transporter were demonstrated by their energetics and structural analyses throughout the 100 ns MD simulations. The current study throws new light on pibrentasvir, venetoclax, and ledipasvir as curative options for multidrug resistant cancers by inhibiting ABCG2 transporter.
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Affiliation(s)
- Mahmoud A A Ibrahim
- Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia, Egypt.
| | - Esraa A A Badr
- Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia, Egypt
| | - Alaa H M Abdelrahman
- Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia, Egypt
| | - Nahlah Makki Almansour
- Department of Biology, College of Science, University of Hafr Al Batin, Hafr Al Batin, Saudi Arabia
| | - Ahmed M Shawky
- Science and Technology Unit (STU), Umm Al-Qura University, Makkah, Saudi Arabia
| | - Gamal A H Mekhemer
- Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia, Egypt
| | - Faris Alrumaihi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | - Mahmoud F Moustafa
- Department of Biology, College of Science, King Khalid University, Abha, Saudi Arabia
- Department of Botany & Microbiology, Faculty of Science, South Valley University, Qena, Egypt
| | - Mohamed A M Atia
- Molecular Genetics and Genome Mapping Laboratory, Genome Mapping Department, Agricultural Genetic Engineering Research Institute (AGERI), Agricultural Research Center (ARC), Giza, Egypt.
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9
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Medically Important Alterations in Transport Function and Trafficking of ABCG2. Int J Mol Sci 2021; 22:ijms22062786. [PMID: 33801813 PMCID: PMC8001156 DOI: 10.3390/ijms22062786] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 02/06/2023] Open
Abstract
Several polymorphisms and mutations in the human ABCG2 multidrug transporter result in reduced plasma membrane expression and/or diminished transport function. Since ABCG2 plays a pivotal role in uric acid clearance, its malfunction may lead to hyperuricemia and gout. On the other hand, ABCG2 residing in various barrier tissues is involved in the innate defense mechanisms of the body; thus, genetic alterations in ABCG2 may modify the absorption, distribution, excretion of potentially toxic endo- and exogenous substances. In turn, this can lead either to altered therapy responses or to drug-related toxic reactions. This paper reviews the various types of mutations and polymorphisms in ABCG2, as well as the ways how altered cellular processing, trafficking, and transport activity of the protein can contribute to phenotypic manifestations. In addition, the various methods used for the identification of the impairments in ABCG2 variants and the different approaches to correct these defects are overviewed.
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10
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Kroll T, Prescher M, Smits SHJ, Schmitt L. Structure and Function of Hepatobiliary ATP Binding Cassette Transporters. Chem Rev 2020; 121:5240-5288. [PMID: 33201677 DOI: 10.1021/acs.chemrev.0c00659] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The liver is beyond any doubt the most important metabolic organ of the human body. This function requires an intensive crosstalk within liver cellular structures, but also with other organs. Membrane transport proteins are therefore of upmost importance as they represent the sensors and mediators that shuttle signals from outside to the inside of liver cells and/or vice versa. In this review, we summarize the known literature of liver transport proteins with a clear emphasis on functional and structural information on ATP binding cassette (ABC) transporters, which are expressed in the human liver. These primary active membrane transporters form one of the largest families of membrane proteins. In the liver, they play an essential role in for example bile formation or xenobiotic export. Our review provides a state of the art and comprehensive summary of the current knowledge of hepatobiliary ABC transporters. Clearly, our knowledge has improved with a breath-taking speed over the last few years and will expand further. Thus, this review will provide the status quo and will lay the foundation for new and exciting avenues in liver membrane transporter research.
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Affiliation(s)
- Tim Kroll
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Martin Prescher
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Sander H J Smits
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany.,Center for Structural Studies, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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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] [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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Orlando BJ, Liao M. ABCG2 transports anticancer drugs via a closed-to-open switch. Nat Commun 2020; 11:2264. [PMID: 32385283 PMCID: PMC7210939 DOI: 10.1038/s41467-020-16155-2] [Citation(s) in RCA: 125] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/16/2020] [Indexed: 12/18/2022] Open
Abstract
ABCG2 is an ABC transporter that extrudes a variety of compounds from cells, and presents an obstacle in treating chemotherapy-resistant cancers. Despite recent structural insights, no anticancer drug bound to ABCG2 has been resolved, and the mechanisms of multidrug transport remain obscure. Such a gap of knowledge limits the development of novel compounds that block or evade this critical molecular pump. Here we present single-particle cryo-EM studies of ABCG2 in the apo state, and bound to the three structurally distinct chemotherapeutics. Without the binding of conformation-selective antibody fragments or inhibitors, the resting ABCG2 adopts a closed conformation. Our cryo-EM, biochemical, and functional analyses reveal the binding mode of three chemotherapeutic compounds, demonstrate how these molecules open the closed conformation of the transporter, and establish that imatinib is particularly effective in stabilizing the inward facing conformation of ABCG2. Together these studies reveal the previously unrecognized conformational cycle of ABCG2. ABCG2 is a human ABC transporter that actively extrudes a wide variety of compounds from cells but the mechanisms of multidrug transport remain obscure. Here authors present cryo-EM structures of ABCG2 in the apo state, and bound to the three structurally distinct chemotherapeutics and demonstrate how these molecules open the closed conformation of the transporter.
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Affiliation(s)
- Benjamin J Orlando
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Maofu Liao
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA.
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13
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Kovacsics D, Brózik A, Tihanyi B, Matula Z, Borsy A, Mészáros N, Szabó E, Németh E, Fóthi Á, Zámbó B, Szüts D, Várady G, Orbán TI, Apáti Á, Sarkadi B. Precision-engineered reporter cell lines reveal ABCG2 regulation in live lung cancer cells. Biochem Pharmacol 2020; 175:113865. [PMID: 32142727 DOI: 10.1016/j.bcp.2020.113865] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/18/2020] [Indexed: 12/19/2022]
Abstract
Expression of the ABCG2 multidrug transporter is a marker of cancer stem cells and a predictor of recurrent malignant disease. Understanding how human ABCG2 expression is modulated by pharmacotherapy is crucial in guiding therapeutic recommendations and may aid rational drug development. Genome edited reporter cells are useful in investigating gene regulation and visualizing protein activity in live cells but require precise targeting to preserve native regulatory regions. Here, we describe a fluorescent reporter assay that allows the noninvasive assessment of ABCG2 regulation in human lung adenocarcinoma cells. Using CRISPR-Cas9 gene editing coupled with homology-directed repair, we targeted an EGFP coding sequence to the translational start site of ABCG2, generating ABCG2 knock-out and in situ tagged ABCG2 reporter cells. Using the engineered cell lines, we show that ABCG2 is upregulated by a number of anti-cancer medications, HDAC inhibitors, hypoxia-mimicking agents and glucocorticoids, supporting a model in which ABCG2 is under the control of a general stress response. To our knowledge, this is the first description of a fluorescent reporter assay system designed to follow the endogenous regulation of a human ABC transporter in live cells. The information gained may guide therapy recommendations and aid rational drug design.
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Affiliation(s)
- Daniella Kovacsics
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Anna Brózik
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Borbála Tihanyi
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Zsolt Matula
- South-Pest Hospital Centre, National Institute of Hematology and Infectious Diseases, Laboratory of Molecular and Cytogenetics, Budapest, Hungary
| | - Adrienn Borsy
- South-Pest Hospital Centre, National Institute of Hematology and Infectious Diseases, Laboratory of Molecular and Cytogenetics, Budapest, Hungary
| | - Nikolett Mészáros
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Edit Szabó
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Eszter Németh
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Ábel Fóthi
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Boglárka Zámbó
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Dávid Szüts
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - György Várady
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Tamás I Orbán
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Ágota Apáti
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Balázs Sarkadi
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary.
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14
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Spectroscopic and calorimetric studies of interactions between mitoxantrone and cucurbituril Q7 in aqueous solutions. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111190] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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15
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Arnst KE, Wang Y, Lei ZN, Hwang DJ, Kumar G, Ma D, Parke DN, Chen Q, Yang J, White SW, Seagroves TN, Chen ZS, Miller DD, Li W. Colchicine Binding Site Agent DJ95 Overcomes Drug Resistance and Exhibits Antitumor Efficacy. Mol Pharmacol 2019; 96:73-89. [PMID: 31043459 PMCID: PMC6553560 DOI: 10.1124/mol.118.114801] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 04/21/2019] [Indexed: 02/05/2023] Open
Abstract
Interfering with microtubule dynamics is a well-established strategy in cancer treatment; however, many microtubule-targeting agents are associated with drug resistance and adverse effects. Substantial evidence points to ATP-binding cassette (ABC) transporters as critical players in the development of resistance. Herein, we demonstrate the efficacy of DJ95 (2-(1H-indol-6-yl)-4-(3,4,5-trimethoxyphenyl)-1H-imidazo[4,5-c]pyridine), a novel tubulin inhibitor, in a variety of cancer cell lines, including malignant melanomas, drug-selected resistant cell lines, specific ABC transporter-overexpressing cell lines, and the National Cancer Institute 60 cell line panel. DJ95 treatment inhibited cancer cell migration, caused morphologic changes to the microtubule network foundation, and severely disrupted mitotic spindle formation of mitotic cells. The high-resolution crystal structure of DJ95 in complex with tubulin protein and the detailed molecular interactions confirmed its direct binding to the colchicine site. In vitro pharmacological screening of DJ95 using SafetyScreen44 (Eurofins Cerep-Panlabs) revealed no significant off-target interactions, and pharmacokinetic analysis showed that DJ95 was maintained at therapeutically relevant plasma concentrations for up to 24 hours in mice. In an A375 xenograft model in nude mice, DJ95 inhibited tumor growth and disrupted tumor vasculature in xenograft tumors. These results demonstrate that DJ95 is potent against a variety of cell lines, demonstrated greater potency to ABC transporter-overexpressing cell lines than existing tubulin inhibitors, directly targets the colchicine binding domain, exhibits significant antitumor efficacy, and demonstrates vascular-disrupting properties. Collectively, these data suggest that DJ95 has great potential as a cancer therapeutic, particularly for multidrug resistance phenotypes, and warrants further development. SIGNIFICANCE STATEMENT: Paclitaxel is a widely used tubulin inhibitor for cancer therapy, but its clinical efficacy is often limited by the development of multidrug resistance. In this study, we reported the preclinical characterization of a new tubulin inhibitor DJ95, and demonstrated its abilities to overcome paclitaxel resistance, disrupt tumor vasculature, and exhibit significant antitumor efficacy.
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Affiliation(s)
- Kinsie E Arnst
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Yuxi Wang
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Zi-Ning Lei
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Dong-Jin Hwang
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Gyanendra Kumar
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Dejian Ma
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Deanna N Parke
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Qiang Chen
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Jinliang Yang
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Stephen W White
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Tiffany N Seagroves
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Zhe-Sheng Chen
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Duane D Miller
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
| | - Wei Li
- Department of Pharmaceutical Sciences, College of Pharmacy (K.E.A., D.-J.H., D.M., D.D.M., W.L.), and Department of Pathology (D.N.P., T.N.S.), the University of Tennessee Health Science Center, Memphis, Tennessee; State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center of Biotherapy (Y.W., Q.C., J.Y.), and Department of Respiratory Medicine (Y.W.), West China Hospital, Sichuan University, Chengdu, China; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York (Z.-N.L., Z.-S.C.); and Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee (G.K., S.W.W.)
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16
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Clinically relevant mutations in the ABCG2 transporter uncovered by genetic analysis linked to erythrocyte membrane protein expression. Sci Rep 2018; 8:7487. [PMID: 29749379 PMCID: PMC5945641 DOI: 10.1038/s41598-018-25695-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 04/26/2018] [Indexed: 12/13/2022] Open
Abstract
The ABCG2 membrane protein is a key xeno- and endobiotic transporter, modulating the absorption and metabolism of pharmacological agents and causing multidrug resistance in cancer. ABCG2 is also involved in uric acid elimination and its impaired function is causative in gout. Analysis of ABCG2 expression in the erythrocyte membranes of healthy volunteers and gout patients showed an enrichment of lower expression levels in the patients. By genetic screening based on protein expression, we found a relatively frequent, novel ABCG2 mutation (ABCG2-M71V), which, according to cellular expression studies, causes reduced protein expression, although with preserved transporter capability. Molecular dynamics simulations indicated a stumbled dynamics of the mutant protein, while ABCG2-M71V expression in vitro could be corrected by therapeutically relevant small molecules. These results suggest that personalized medicine should consider this newly discovered ABCG2 mutation, and genetic analysis linked to protein expression provides a new tool to uncover clinically important mutations in membrane proteins.
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17
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Almeida D, Pinho R, Correia V, Soares J, Bastos MDL, Carvalho F, Capela JP, Costa VM. Mitoxantrone is More Toxic than Doxorubicin in SH-SY5Y Human Cells: A 'Chemobrain' In Vitro Study. Pharmaceuticals (Basel) 2018; 11:ph11020041. [PMID: 29734752 PMCID: PMC6027466 DOI: 10.3390/ph11020041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/28/2018] [Accepted: 04/29/2018] [Indexed: 12/20/2022] Open
Abstract
The potential neurotoxic effects of anticancer drugs, like doxorubicin (DOX) and mitoxantrone (MTX; also used in multiple sclerosis), are presently important reasons for concern, following epidemiological data indicating that cancer survivors submitted to chemotherapy may suffer cognitive deficits. We evaluated the in vitro neurotoxicity of two commonly used chemotherapeutic drugs, DOX and MTX, and study their underlying mechanisms in the SH-SY5Y human neuronal cell model. Undifferentiated human SH-SY5Y cells were exposed to DOX or MTX (0.13, 0.2 and 0.5 μM) for 48 h and two cytotoxicity assays were performed, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) reduction and the neutral red (NR) incorporation assays. Phase contrast microphotographs, Hoechst, and acridine orange/ethidium bromide stains were performed. Mitochondrial membrane potential was also assessed. Moreover, putative protective drugs, namely the antioxidants N-acetyl-l-cysteine (NAC; 1 mM) and 100 μM tiron, the inhibitor of caspase-3/7, Ac-DEVD-CHO (100 μM), and a protein synthesis inhibitor, cycloheximide (CHX; 10 nM), were tested to prevent DOX- or MTX-induced toxicity. The MTT reduction assay was also done in differentiated SH-SY5Y cells following exposure to 0.2 μM DOX or MTX. MTX was more toxic than DOX in both cytotoxicity assays and according to the morphological analyses. MTX also evoked a higher number of apoptotic nuclei than DOX. Both drugs, at the 0.13 μM concentration, caused mitochondrial membrane potential depolarization after a 48-h exposure. Regarding the putative neuroprotectors, 1 mM NAC was not able to prevent the cytotoxicity caused by either drug. Notwithstanding, 100 μM tiron was capable of partially reverting MTX-induced cytotoxicity in the NR uptake assay. One hundred μM Ac-DEVD-CHO and 10 nM cycloheximide (CHX) also partially prevented the toxicity induced by DOX in the NR uptake assay. MTX was more toxic than DOX in differentiated SH-SY5Y cells, while MTX had similar toxicity in differentiated and undifferentiated SH-SY5Y cells. In fact, MTX was the most neurotoxic drug tested and the mechanisms involved seem dissimilar among drugs. Thus, its toxicity mechanisms need to be further investigated as to determine the putative neurotoxicity for multiple sclerosis and cancer patients.
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Affiliation(s)
- Daniela Almeida
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Rita Pinho
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Verónica Correia
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Jorge Soares
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Maria de Lourdes Bastos
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Félix Carvalho
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - João Paulo Capela
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
- FP-ENAS (Unidade de Investigação UFP em Energia, Ambiente e Saúde), CEBIMED (Centro de Estudos em Biomedicina), Faculdade de Ciências da Saúde, Universidade Fernando Pessoa, 4249-004 Porto, Portugal.
| | - Vera Marisa Costa
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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18
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A new fluorescent dye accumulation assay for parallel measurements of the ABCG2, ABCB1 and ABCC1 multidrug transporter functions. PLoS One 2018; 13:e0190629. [PMID: 29342177 PMCID: PMC5771559 DOI: 10.1371/journal.pone.0190629] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/18/2017] [Indexed: 01/01/2023] Open
Abstract
ABC multidrug transporters are key players in cancer multidrug resistance and in general xenobiotic elimination, thus their functional assays provide important tools for research and diagnostic applications. In this study we have examined the potential interactions of three key human ABC multidrug transporters with PhenGreen diacetate (PGD), a cell permeable fluorescent metal ion indicator. The non-fluorescent, hydrophobic PGD rapidly enters the cells and, after cleavage by cellular esterases, in the absence of quenching metal ions, PhenGreen (PG) becomes highly fluorescent. We found that in cells expressing functional ABCG2, ABCB1, or ABCC1 transporters, cellular PG fluorescence is strongly reduced. This fluorescence signal in the presence of specific transporter inhibitors is increased to the fluorescence levels in the control cells. Thus the PG accumulation assay is a new, unique tool for the parallel determination of the function of the ABCG2, ABCB1, and ABCC1 multidrug transporters. Since PG has very low cellular toxicity, the PG accumulation assay also allows the selection, separation and culturing of selected cell populations expressing either of these transporters.
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19
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Khunweeraphong N, Stockner T, Kuchler K. The structure of the human ABC transporter ABCG2 reveals a novel mechanism for drug extrusion. Sci Rep 2017; 7:13767. [PMID: 29061978 PMCID: PMC5653816 DOI: 10.1038/s41598-017-11794-w] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 08/31/2017] [Indexed: 12/13/2022] Open
Abstract
The human ABC transporter ABCG2 (Breast Cancer Resistance Protein, BCRP) is implicated in anticancer resistance, in detoxification across barriers and linked to gout. Here, we generate a novel atomic model of ABCG2 using the crystal structure of ABCG5/G8. Extensive mutagenesis verifies the structure, disclosing hitherto unrecognized essential residues and domains in the homodimeric ABCG2 transporter. The elbow helix, the first intracellular loop (ICL1) and the nucleotide-binding domain (NBD) constitute pivotal elements of the architecture building the transmission interface that borders a central cavity which acts as a drug trap. The transmission interface is stabilized by salt-bridge interactions between the elbow helix and ICL1, as well as within ICL1, which is essential to control the conformational switch of ABCG2 to the outward-open drug-releasing conformation. Importantly, we propose that ICL1 operates like a molecular spring that holds the NBD dimer close to the membrane, thereby enabling efficient coupling of ATP hydrolysis during the catalytic cycle. These novel mechanistic data open new opportunities to therapeutically target ABCG2 in the context of related diseases.
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Affiliation(s)
- Narakorn Khunweeraphong
- Center for Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, Campus Vienna Biocenter, Dr. Bohr-Gasse 9/2, A-1030, Vienna, Austria
| | - Thomas Stockner
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Währingerstrasse 13A, A-1090, Vienna, Austria
| | - Karl Kuchler
- Center for Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, Campus Vienna Biocenter, Dr. Bohr-Gasse 9/2, A-1030, Vienna, Austria.
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20
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Konda SK, Maliki R, McGrath S, Parker BS, Robinson T, Spurling A, Cheong A, Lock P, Pigram PJ, Phillips DR, Wallace L, Day AI, Collins JG, Cutts SM. Encapsulation of Mitoxantrone within Cucurbit[8]uril Decreases Toxicity and Enhances Survival in a Mouse Model of Cancer. ACS Med Chem Lett 2017; 8:538-542. [PMID: 28523107 DOI: 10.1021/acsmedchemlett.7b00090] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 04/24/2017] [Indexed: 11/28/2022] Open
Abstract
Mitoxantrone was efficiently encapsulated within cucurbit[8]uril in a 2:1 complex where the two mitoxantrone molecules were symmetrically located through both portals of a cucurbit[8]uril cage. The novel complex facilitates increased mitoxantrone uptake in mouse breast cancer cells and decreases the toxicity of the drug in healthy mice. In an orthotopic mouse model of metastatic breast cancer the complex still maintains in vivo anticancer activity compared to the free drug, yet provides a statistically significant increase in the survival of these mice compared to conventional mitoxantrone treatment. This new low toxicity formulation offers the possibility to increase mitoxantrone dose and thus maximize efficacy while managing the dose limiting side effects.
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Affiliation(s)
- Shyam K. Konda
- School
of Physical, Environmental and Mathematical Sciences, University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2600, Australia
| | - Ruqaya Maliki
- Department
of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC 3086, Australia
- Centre for Materials and Surface Science & Department of Physics and Chemistry, La Trobe University, Melbourne, VIC 3086, Australia
| | - Sean McGrath
- Department
of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC 3086, Australia
| | - Belinda S. Parker
- Department
of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC 3086, Australia
| | - Tina Robinson
- Department
of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC 3086, Australia
| | - Alex Spurling
- Department
of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC 3086, Australia
| | - Alison Cheong
- Department
of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC 3086, Australia
| | - Peter Lock
- Department
of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC 3086, Australia
| | - Paul J. Pigram
- Centre for Materials and Surface Science & Department of Physics and Chemistry, La Trobe University, Melbourne, VIC 3086, Australia
| | - Don R. Phillips
- Department
of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC 3086, Australia
| | - Lynne Wallace
- School
of Physical, Environmental and Mathematical Sciences, University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2600, Australia
| | - Anthony I. Day
- School
of Physical, Environmental and Mathematical Sciences, University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2600, Australia
| | - J. Grant Collins
- School
of Physical, Environmental and Mathematical Sciences, University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2600, Australia
| | - Suzanne M. Cutts
- Department
of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC 3086, Australia
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21
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Tarapcsák S, Szalóki G, Telbisz Á, Gyöngy Z, Matúz K, Csősz É, Nagy P, Holb IJ, Rühl R, Nagy L, Szabó G, Goda K. Interactions of retinoids with the ABC transporters P-glycoprotein and Breast Cancer Resistance Protein. Sci Rep 2017; 7:41376. [PMID: 28145501 PMCID: PMC5286421 DOI: 10.1038/srep41376] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 12/20/2016] [Indexed: 01/16/2023] Open
Abstract
Retinoids – derivatives of vitamin A – are important cell permeant signaling molecules that regulate gene expression through activation of nuclear receptors. P-glycoprotein (Pgp) and ABCG2 are plasma membrane efflux transporters affecting the tissue distribution of numerous structurally unrelated lipophilic compounds. In the present work we aimed to study the interaction of the above ABC transporters with retinoid derivatives. We have found that 13-cis-retinoic acid, retinol and retinyl-acetate inhibited the Pgp and ABCG2 mediated substrate transport as well as the substrate stimulated ATPase activity of these transporters. Interestingly, 9-cis-retinoic acid and ATRA (all-trans retinoic acid), both are stereoisomers of 13-cis-retinoic acid, did not have any effect on the transporters’ activity. Our fluorescence anisotropy measurements revealed that 13-cis-retinoic acid, retinol and retinyl-acetate selectively increase the viscosity and packing density of the membrane. Thus, the mixed-type inhibition of both transporters by retinol and ABCG2 by 13-cis-retinoic acid may be the collective result of direct interactions of these retinoids with the substrate binding site(s) and of indirect interactions mediated by their membrane rigidifying effects.
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Affiliation(s)
- Szabolcs Tarapcsák
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Gábor Szalóki
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Ágnes Telbisz
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, H-1117 Magyar tudósok körútja 2, P.O.B. 286, Hungary
| | - Zsuzsanna Gyöngy
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Krisztina Matúz
- Department of Biochemistry and Molecular Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Éva Csősz
- Department of Biochemistry and Molecular Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Péter Nagy
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Imre J Holb
- Institute of Horticulture, University of Debrecen, Debrecen, H-4015 Böszörményi út 138, P.O.B. 400, Hungary.,Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, H-1525 Hermann Ottó út 15, P.O.B. 525, Hungary
| | - Ralph Rühl
- MTA-DE, Public Health Research Group of the Hungarian Academy of Sciences, Faculty of Public Health, University of Debrecen, Debrecen, H-4028 Kassai út 26, P.O.B. 400, Hungary
| | - László Nagy
- Department of Biochemistry and Molecular Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Gábor Szabó
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
| | - Katalin Goda
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, H-4002 Egyetem tér 1, P.O.B. 400, Hungary
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22
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Gold nanostars for efficient in vitro and in vivo real-time SERS detection and drug delivery via plasmonic-tunable Raman/FTIR imaging. Biomaterials 2016; 106:87-97. [DOI: 10.1016/j.biomaterials.2016.08.014] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/06/2016] [Accepted: 08/10/2016] [Indexed: 11/18/2022]
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23
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Montanari F, Cseke A, Wlcek K, Ecker GF. Virtual Screening of DrugBank Reveals Two Drugs as New BCRP Inhibitors. SLAS DISCOVERY 2016; 22:86-93. [PMID: 27401583 PMCID: PMC5302078 DOI: 10.1177/1087057116657513] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The breast cancer resistance protein (BCRP) is an ABC transporter playing a crucial role in the pharmacokinetics of drugs. The early identification of substrates and inhibitors of this efflux transporter can help to prevent or foresee drug-drug interactions. In this work, we built a ligand-based in silico classification model to predict the inhibitory potential of drugs toward BCRP. The model was applied as a virtual screening technique to identify potential inhibitors among the small-molecules subset of DrugBank. Ten compounds were selected and tested for their capacity to inhibit mitoxantrone efflux in BCRP-expressing PLB985 cells. Results identified cisapride (IC50 = 0.4 µM) and roflumilast (IC50 = 0.9 µM) as two new BCRP inhibitors. The in silico strategy proved useful to prefilter potential drug-drug interaction perpetrators among a database of small molecules and can reduce the amount of compounds to test.
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Affiliation(s)
- Floriane Montanari
- 1 University of Vienna, Department of Pharmaceutical Chemistry, Vienna, Austria
| | - Anna Cseke
- 1 University of Vienna, Department of Pharmaceutical Chemistry, Vienna, Austria
| | - Katrin Wlcek
- 1 University of Vienna, Department of Pharmaceutical Chemistry, Vienna, Austria
| | - Gerhard F Ecker
- 1 University of Vienna, Department of Pharmaceutical Chemistry, Vienna, Austria
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24
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Measuring Cell Death by Propidium Iodide Uptake and Flow Cytometry. Cold Spring Harb Protoc 2016; 2016:2016/7/pdb.prot087163. [PMID: 27371595 DOI: 10.1101/pdb.prot087163] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Propidium iodide (PI) is a small fluorescent molecule that binds to DNA but cannot passively traverse into cells that possess an intact plasma membrane. PI uptake versus exclusion can be used to discriminate dead cells, in which plasma membranes become permeable regardless of the mechanism of death, from live cells with intact membranes. PI is excited by wavelengths between 400 and 600 nm and emits light between 600 and 700 nm, and is therefore compatible with lasers and photodetectors commonly available in flow cytometers. This protocol for PI staining can be used to quantitate cell death in most modern research facilities and universities.
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25
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Cicha I, Scheffler L, Ebenau A, Lyer S, Alexiou C, Goppelt-Struebe M. Mitoxantrone-loaded superparamagnetic iron oxide nanoparticles as drug carriers for cancer therapy: Uptake and toxicity in primary human tubular epithelial cells. Nanotoxicology 2015; 10:557-66. [DOI: 10.3109/17435390.2015.1095364] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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26
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Rudashevskaya EL, Stockner T, Trauner M, Freissmuth M, Chiba P. Pharmacological correction of misfolding of ABC proteins. DRUG DISCOVERY TODAY. TECHNOLOGIES 2015; 12:e87-94. [PMID: 25027379 PMCID: PMC4039138 DOI: 10.1016/j.ddtec.2014.03.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The endoplasmic reticulum (ER) quality control system distinguishes between correctly and incorrectly folded proteins to prevent processing of aberrantly folded conformations along the secretory pathway. Non-synonymous mutations can lead to misfolding of ABC proteins and associated disease phenotypes. Specific phenotypes may at least partially be corrected by small molecules, so-called pharmacological chaperones. Screening for folding correctors is expected to open an avenue for treatment of diseases such as cystic fibrosis and intrahepatic cholestasis.
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Affiliation(s)
- Elena L Rudashevskaya
- Institute of Medical Chemistry, Medical University of Vienna, Waehringerstrasse 10, Vienna, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Medical University of Vienna, Waehringerstrasse 13, Vienna, Austria
| | - Michael Trauner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, Austria
| | - Michael Freissmuth
- Institute of Pharmacology, Medical University of Vienna, Waehringerstrasse 13, Vienna, Austria
| | - Peter Chiba
- Institute of Medical Chemistry, Medical University of Vienna, Waehringerstrasse 10, Vienna, Austria
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27
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Hegedüs C, Telbisz Á, Hegedűs T, Sarkadi B, Özvegy-Laczka C. Lipid regulation of the ABCB1 and ABCG2 multidrug transporters. Adv Cancer Res 2015; 125:97-137. [PMID: 25640268 DOI: 10.1016/bs.acr.2014.10.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This chapter deals with the interactions of two medically important multidrug ABC transporters (MDR-ABC), ABCB1 and ABCG2, with lipid molecules. Both ABCB1 and ABCG2 are capable of transporting a wide range of hydrophobic drugs and xenobiotics and are involved in cancer chemotherapy resistance. Therefore, the exploration of their mechanism of action has major therapeutic consequences. As discussed here in detail, both ABCB1 and ABCG2 are significantly affected by various lipid compounds especially those residing in their close proximity in the plasma membrane. ABCB1 is capable of transporting lipids and lipid derivatives, and thus may alter the general membrane composition by "flopping" membrane lipid constituents, while there is no such information regarding ABCG2. Still, both ABCB1 and ABCG2 show complex interactions with a variety of lipid molecules, and the transporters are significantly modulated by cholesterol and cholesterol derivatives at the posttranslational level. In this chapter, we explore the molecular details of the direct transporter-lipid interactions, the potential role of lipid-sensor domains within the proteins, as well as the application of experimental site-directed mutagenesis, detailed structural studies, and in silico modeling for examining these interactions. We also discuss the regulation of ABCB1 and ABCG2 expression at the transcriptional level, occurring through nuclear receptors involved in lipid sensing. The better understanding of lipid interactions with these medically important MDR-ABC transporters may significantly improve further drug development and clinical treatment options.
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Affiliation(s)
- Csilla Hegedüs
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Ágnes Telbisz
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tamás Hegedűs
- MTA-SE Molecular Biophysics Research Group of the Hungarian Academy of Sciences, Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Balázs Sarkadi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary; MTA-SE Molecular Biophysics Research Group of the Hungarian Academy of Sciences, Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Csilla Özvegy-Laczka
- MTA-SE Molecular Biophysics Research Group of the Hungarian Academy of Sciences, Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary.
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28
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Tan KW, Li Y, Paxton JW, Birch NP, Scheepens A. Identification of novel dietary phytochemicals inhibiting the efflux transporter breast cancer resistance protein (BCRP/ABCG2). Food Chem 2013; 138:2267-74. [DOI: 10.1016/j.foodchem.2012.12.021] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/02/2012] [Accepted: 12/03/2012] [Indexed: 01/03/2023]
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29
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Effects of the lipid environment, cholesterol and bile acids on the function of the purified and reconstituted human ABCG2 protein. Biochem J 2013. [DOI: 10.1042/bj20121485] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The human ABCG2 multidrug transporter actively extrudes a wide range of hydrophobic drugs and xenobiotics recognized by the transporter in the membrane phase. In order to examine the molecular nature of the transporter and its effects on the lipid environment, we have established an efficient protocol for the purification and reconstitution of the functional protein. We found that the drug-stimulated ATPase and the transport activity of ABCG2 are fully preserved by applying excess lipids and mild detergents during solubilization, whereas a detergent-induced dissociation of the ABCG2 dimer causes an irreversible inactivation. By using the purified and reconstituted protein we demonstrate that cholesterol is an essential activator, whereas bile acids are important modulators of ABCG2 activity. Both wild-type ABCG2 and its R482G mutant variant require cholesterol for full activity, although they exhibit different cholesterol sensitivities. Bile acids strongly decrease the basal ABCG2-ATPase activity both in the wild-type ABCG2 and in the mutant variant. These data reinforce the results for the modulatory effects of cholesterol and bile acids of ABCG2 investigated in a complex cell membrane environment. Moreover, these experiments open the possibility to perform functional and structural studies with a purified, reconstituted and highly active ABCG2 multidrug transporter.
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30
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Erdei Z, Sarkadi B, Brózik A, Szebényi K, Várady G, Makó V, Péntek A, Orbán TI, Apáti Á. Dynamic ABCG2 expression in human embryonic stem cells provides the basis for stress response. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 42:169-79. [PMID: 22851001 DOI: 10.1007/s00249-012-0838-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 06/26/2012] [Accepted: 07/09/2012] [Indexed: 12/21/2022]
Abstract
ABCG2 is a plasma membrane multidrug transporter with an established role in the cancer drug-resistance phenotype. This protein is expressed in a variety of tissues, including several types of stem cell. Although ABCG2 is not essential for life, knock-out mice were found to be hypersensitive to xenobiotics and had reduced levels of the side population of hematopoietic stem cells. Previously we have shown that ABCG2 is present in human embryonic stem cell (hESC) lines, with a heterogeneous expression pattern. In this study we examined this heterogeneity, and investigated whether it is related to stress responses in hESCs. We did not find any difference between expression of pluripotency markers in ABCG2-positive and negative hESCs; however, ABCG2-expressing cells had a higher growth rate after cell separation. We found that some harmful conditions (physical stress, drugs, and UV light exposure) are tolerated much better in the presence of ABCG2 protein. This property can be explained by the transporter function which eliminates potential toxic metabolites accumulated during stress conditions. In contrast, mild oxidative stress in hESCs caused rapid internalization of ABCG2, indicating that some environmental factors may induce removal of this transporter from the plasma membrane. On the basis of these results we suggest that a dynamic balance of ABCG2 expression at the population level has the advantage of enabling prompt response to changes in the cellular environment. Such actively maintained heterogeneity might be of evolutionary benefit in protecting special cell types, including pluripotent stem cells.
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Affiliation(s)
- Zsuzsa Erdei
- Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis, University and National Blood Center, Diószegi u. 64., 1113, Budapest, Hungary
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