1
|
Kleinsasser B, Garreis F, Musialik M, Zahn I, Kral B, Kutlu Z, Sahin A, Paulsen F, Schicht M. Molecular detection of lacrimal apparatus and ocular surface - related ABC transporter genes. Ann Anat 2024; 255:152272. [PMID: 38697581 DOI: 10.1016/j.aanat.2024.152272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 04/25/2024] [Accepted: 04/28/2024] [Indexed: 05/05/2024]
Abstract
The ocular system is in constant interaction with the environment and with numerous pathogens. The ATP-binding cassette (ABC) transporters represent one of the largest groups among the transmembrane proteins. Their relevance has been demonstrated for their defense function against biotic and abiotic stress factors, for metabolic processes in tumors and for their importance in the development of resistance to drugs. The aim of this study was to analyze which ABC transporters are expressed at the ocular surface and in the human lacrimal apparatus. Using RT-PCR, all ABC transporters known to date in humans were examined in tissue samples from human cornea, conjunctiva, meibomian glands and lacrimal glands. The RT-PCR analyses revealed the presence of all ABC transporters in the samples examined, although the results for some of the 48 transporters known in human and analyzed were different in the various tissues. The present results provide information on the expression of ABC transporters at the mRNA level on the ocular surface and in the lacrimal system. Their detection forms the basis for follow-up studies at the protein level, which will provide more information about their physiological significance at the ocular surface and in the lacrimal system and which may explain pathological effects such as drug resistance.
Collapse
Affiliation(s)
- Benedikt Kleinsasser
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Fabian Garreis
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Maximilian Musialik
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Ingrid Zahn
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Barbara Kral
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Zeynep Kutlu
- Koc University School of Medicine, Rumelifeneri Yolu, Istanbul 34450, Turkey
| | - Afsun Sahin
- Department of Ophthalmology, Koc University Medical School, Istanbul, Turkey
| | - Friedrich Paulsen
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Martin Schicht
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| |
Collapse
|
2
|
Zhang D, Wei C, Hop CECA, Wright MR, Hu M, Lai Y, Khojasteh SC, Humphreys WG. Intestinal Excretion, Intestinal Recirculation, and Renal Tubule Reabsorption Are Underappreciated Mechanisms That Drive the Distribution and Pharmacokinetic Behavior of Small Molecule Drugs. J Med Chem 2021; 64:7045-7059. [PMID: 34010555 DOI: 10.1021/acs.jmedchem.0c01720] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Drug reabsorption following biliary excretion is well-known as enterohepatic recirculation (EHR). Renal tubular reabsorption (RTR) following renal excretion is also common but not easily assessed. Intestinal excretion (IE) and enteroenteric recirculation (EER) have not been recognized as common disposition mechanisms for metabolically stable and permeable drugs. IE and intestinal reabsorption (IR:EHR/EER), as well as RTR, are governed by dug concentration gradients, passive diffusion, active transport, and metabolism, and together they markedly impact disposition and pharmacokinetics (PK) of small molecule drugs. Disruption of IE, IR, or RTR through applications of active charcoal (AC), transporter knockout (KO), and transporter inhibitors can lead to changes in PK parameters. The impacts of intestinal and renal reabsorption on PK are under-appreciated. Although IE and EER/RTR can be an intrinsic drug property, there is no apparent strategy to optimize compounds based on this property. This review seeks to improve understanding and applications of IE, IR, and RTR mechanisms.
Collapse
Affiliation(s)
- Donglu Zhang
- Department of Drug Metabolism and Pharmacokinetics, Genentech, 1 DNA Way, South San Francisco, California 94080, United States
| | - Cong Wei
- Drug Metabolism and Pharmacokinetics, Biogen, 225 Binney Street, Cambridge, Massachusetts 02142, United States
| | - Cornelis E C A Hop
- Department of Drug Metabolism and Pharmacokinetics, Genentech, 1 DNA Way, South San Francisco, California 94080, United States
| | - Matthew R Wright
- Department of Drug Metabolism and Pharmacokinetics, Genentech, 1 DNA Way, South San Francisco, California 94080, United States
| | - Ming Hu
- University of Houston College of Pharmacy, 4849 Calhoun Road, Houston, Texas 77204, United States
| | - Yurong Lai
- Drug Metabolism and Pharmacokinetics, Gilead Sciences, 333 Lakeside Drive, Foster City, California 94404, United States
| | - S Cyrus Khojasteh
- Department of Drug Metabolism and Pharmacokinetics, Genentech, 1 DNA Way, South San Francisco, California 94080, United States
| | - W Griff Humphreys
- Aranmore Pharma Consulting, 11 Andrew Drive, Lawrenceville, New Jersey 08648, United States
| |
Collapse
|
3
|
Latimer I, Chand R, Cridge B. The in vitro toxicity of nitrile and epithionitrile derivatives of glucosinolates from swedes ( Brassica napus) in human and bovine liver cells. N Z Vet J 2021; 69:165-173. [PMID: 33570481 DOI: 10.1080/00480169.2021.1875933] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AIM To investigate the direct in vitro toxicity in human and bovine liver cells, and inhibition of activity of ATP-binding cassette transporter G2 (ABCG2) and cytochrome P450 3A4 (CYP3A4) by five nitrile and epithionitrile derivatives from swede (Brassica napus). METHODS The following compounds were investigated: 1-cyano-2-hydroxy-3-butene (CHB, epithionitrile derivative of progoitrin), 1-cyano-2-hydroxy-3,4-epithiobutane (epithionitrile derivative of progoitrin), 3-butenenitrile (nitrile from sinigrin), 4-pentenenitrile (nitrile from gluconapin), and 5-hexenenitrile (nitrile from glucobrassicanapin). Direct cytotoxicity was assessed by incubating the compounds (at 100 mM, 200 mM, 2 M) with human (HepG2) hepatocellular carcinoma cells or bovine primary hepatocytes for 24 hours. Cell viability was then assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cytotoxicity in Hep2G cells was also assessed after incubation for 72 hours at sub-chronic concentrations (1, 2.5, 5, 10, 15, 20 µM) and for combinations of compounds (20 µM). The ability of compounds to inhibit activity of the ABCG2 transporter and the CYP3A4 enzyme were assessed using human ABCG2 vesicles and demethylation of erythromycin by rat liver microsomes, respectively. RESULTS No reduction of cell viability compared to control assays was observed when the tested compounds were incubated with Hep2G cells or bovine liver cells at concentrations up to 2 mM for 24 hours or with Hep2G cells at concentrations up to 20 µM for 72 hours. None of the five tested compounds inhibited the ability of the ABCG2 transporter to transport the fluorescent substrate at concentrations up to 2 mM. Furthermore, no inhibition of CYP3A4 activity (measured as N-demethylation of erythromycin) was observed for CHB up to 2 mM. CONCLUSION This study suggests that under these conditions, the selected nitrile or epithionitrile derivatives of glucosinolates are not hepatotoxic in vitro.
Collapse
Affiliation(s)
- I Latimer
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| | - R Chand
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| | - B Cridge
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| |
Collapse
|
4
|
Hodin S, Basset T, Jacqueroux E, Delezay O, Clotagatide A, Perek N, Mismetti P, Delavenne X. In Vitro Comparison of the Role of P-Glycoprotein and Breast Cancer Resistance Protein on Direct Oral Anticoagulants Disposition. Eur J Drug Metab Pharmacokinet 2018; 43:183-191. [PMID: 28895074 DOI: 10.1007/s13318-017-0434-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Pharmacokinetics of direct oral anticoagulants (DOACs) are influenced by ATP-binding cassette (ABC) transporters such as P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP). OBJECTIVES To better understand the role of transporters in DOAC disposition, we evaluated and compared the permeabilities and transport properties of these drugs. METHODS Bidirectional permeabilities of DOACs were investigated across Caco-2 cells monolayer. Transport assays were performed using different concentrations of DOAC and specific inhibitors of ABC transporters. Cell model functionality was evaluated by transport assay of two positive control substrates. RESULTS The results of transport assays suggest a concentration-dependent efflux of apixaban, dabigatran etexilate and edoxaban, whereas the efflux transport of rivaroxaban did not seem to depend on concentration. Verapamil, a strong inhibitor of P-gp, decreased DOAC efflux in the Caco-2 cell model by 12-87%, depending on the drug tested. Ko143 reduced BCRP-mediated DOAC efflux in Caco-2 cells by 46-76%. CONCLUSION This study allowed identification of three different profiles of ABC carrier-mediated transport: predominantly P-gp-dependent transport (dabigatran), preferential BCRP-dependent transport (apixaban) and approximately equivalent P-gp and BCRP-mediated transport (edoxaban and rivaroxaban).
Collapse
Affiliation(s)
- Sophie Hodin
- INSERM, U1059, Dysfonction Vasculaire et Hémostase, Saint-Étienne, France.,Université de Lyon, 42023, Saint-Étienne, France
| | - Thierry Basset
- INSERM, U1059, Dysfonction Vasculaire et Hémostase, Saint-Étienne, France.,Université de Lyon, 42023, Saint-Étienne, France.,Laboratoire de Pharmacologie-Toxicologie-Gaz du sang, Plateau de Biologie-Hôpital Nord, CHU de Saint-Etienne, 42055, Saint-Étienne, France
| | - Elodie Jacqueroux
- INSERM, U1059, Dysfonction Vasculaire et Hémostase, Saint-Étienne, France.,Université de Lyon, 42023, Saint-Étienne, France
| | - Olivier Delezay
- INSERM, U1059, Dysfonction Vasculaire et Hémostase, Saint-Étienne, France.,Université de Lyon, 42023, Saint-Étienne, France
| | - Anthony Clotagatide
- Service de Radiopharmacie, CHU de Saint-Etienne, 42055, Saint-Étienne, France
| | - Nathalie Perek
- INSERM, U1059, Dysfonction Vasculaire et Hémostase, Saint-Étienne, France.,Université de Lyon, 42023, Saint-Étienne, France
| | - Patrick Mismetti
- INSERM, U1059, Dysfonction Vasculaire et Hémostase, Saint-Étienne, France.,Université de Lyon, 42023, Saint-Étienne, France.,Unité de Recherche Clinique Innovation et Pharmacologie, CHU de Saint-Etienne, 42055, Saint-Étienne, France
| | - Xavier Delavenne
- INSERM, U1059, Dysfonction Vasculaire et Hémostase, Saint-Étienne, France. .,Université de Lyon, 42023, Saint-Étienne, France. .,Laboratoire de Pharmacologie-Toxicologie-Gaz du sang, Plateau de Biologie-Hôpital Nord, CHU de Saint-Etienne, 42055, Saint-Étienne, France.
| |
Collapse
|
5
|
Expression and function of Abcg4 in the mouse blood-brain barrier: role in restricting the brain entry of amyloid-β peptide. Sci Rep 2017; 7:13393. [PMID: 29042617 PMCID: PMC5645361 DOI: 10.1038/s41598-017-13750-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 09/27/2017] [Indexed: 12/04/2022] Open
Abstract
ABCG4 is an ATP-binding cassette transmembrane protein which has been shown, in vitro, to participate in the cellular efflux of desmosterol and amyloid-β peptide (Aβ). ABCG4 is highly expressed in the brain, but its localization and function at the blood-brain barrier (BBB) level remain unknown. We demonstrate by qRT-PCR and confocal imaging that mouse Abcg4 is expressed in the brain capillary endothelial cells. Modelling studies of the Abcg4 dimer suggested that desmosterol showed thermodynamically favorable binding at the putative sterol-binding site, and this was greater than for cholesterol. Additionally, unbiased docking also showed Aβ binding at this site. Using a novel Abcg4-deficient mouse model, we show that Abcg4 was able to export Aβ and desmosterol at the BBB level and these processes could be inhibited by probucol and L-thyroxine. Our assay also showed that desmosterol antagonized the export of Aβ, presumably as both bind at the sterol-binding site on Abcg4. We show for the first time that Abcg4 may function in vivo to export Aβ at the BBB, in a process that can be antagonized by its putative natural ligand, desmosterol (and possibly cholesterol).
Collapse
|
6
|
Li Y, Zhang J, Xu P, Sun B, Zhong Z, Liu C, Ling Z, Chen Y, Shu N, Zhao K, Liu L, Liu X. Acute liver failure impairs function and expression of breast cancer-resistant protein (BCRP) at rat blood-brain barrier partly via ammonia-ROS-ERK1/2 activation. J Neurochem 2016; 138:282-94. [DOI: 10.1111/jnc.13666] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 05/04/2016] [Accepted: 05/07/2016] [Indexed: 12/26/2022]
Affiliation(s)
- Ying Li
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| | - Ji Zhang
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| | - Ping Xu
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| | - Binbin Sun
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| | - Zeyu Zhong
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| | - Can Liu
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| | - Zhaoli Ling
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| | - Yang Chen
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| | - Nan Shu
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| | - Kaijing Zhao
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| | - Li Liu
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| | - Xiaodong Liu
- Center of Drug Metabolism and Pharmacokinetics; China Pharmaceutical University; Nanjing China
| |
Collapse
|
7
|
Hoque MT, Shah A, More V, Miller DS, Bendayan R. In vivo and ex vivo regulation of breast cancer resistant protein (Bcrp) by peroxisome proliferator-activated receptor alpha (Pparα) at the blood-brain barrier. J Neurochem 2015; 135:1113-22. [PMID: 26465636 DOI: 10.1111/jnc.13389] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 09/15/2015] [Accepted: 09/16/2015] [Indexed: 12/13/2022]
Abstract
Breast cancer resistance protein (Bcrp/Abcg2) localized at the blood-brain barrier (BBB) limits permeability into the brain of many xenobiotics, including pharmacological agents. Peroxisome proliferator-activated receptor α (Pparα), a ligand-activated transcription factor, primarily involved in lipid metabolism, has been shown to regulate the functional expression of Bcrp in human cerebral microvascular endothelial cells (hCMEC/D3). The aim of this study was to investigate ex vivo and in vivo, the regulation of Bcrp by Pparα in an intact BBB. Ex vivo quantitative real-time PCR and immunoblot analyses showed significant up-regulation of Abcg2/Bcrp mRNA and protein levels in CD-1 mouse brain capillaries incubated with clofibrate, a Pparα ligand. Fluorescence-based transport assays in CD-1 and C57BL/6 brain capillaries showed that exposure to clofibrate significantly increased Bcrp transport activity. This increase was not observed in capillaries isolated from Pparα knockout mice. In vivo, we found: i) significant Bcrp protein up-regulation in clofibrate-dosed CD-1 and C57BL/6 capillary lysates, but no effect in Pparα knockout capillary lysates, and ii) significantly increased Bcrp transport activity in capillaries isolated from clofibrate-treated mice. These results demonstrate an increase in Bcrp functional expression by Pparα in brain capillaries, and suggest that Pparα is another nuclear receptor that can contribute to the regulation of membrane efflux transporters and drug permeability at the BBB. We propose the involvement of the following pathways in clofibrate-mediated induction of the drug transporter Abcg2/Bcrp mRNA, protein expression and function by the nuclear receptor Pparα, in mouse brain capillary endothelial cells. Upon activation with clofibrate (Pparα, ligand), Pparα complex translocates from the cytoplasm into the nucleus and further recruits coactivators and transcription machinery which induce the transcription of Abcg2 gene and ultimately results in upregulation of Bcrp protein expression and function. These findings have significant implications since Bcrp is known to play an important role at the BBB in preventing the permeability of several xenobiotics and drugs into the brain.
Collapse
Affiliation(s)
- Md Tozammel Hoque
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Arpit Shah
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Vijay More
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - David S Miller
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Reina Bendayan
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
8
|
Tebay LE, Robertson H, Durant ST, Vitale SR, Penning TM, Dinkova-Kostova AT, Hayes JD. Mechanisms of activation of the transcription factor Nrf2 by redox stressors, nutrient cues, and energy status and the pathways through which it attenuates degenerative disease. Free Radic Biol Med 2015; 88:108-146. [PMID: 26122708 PMCID: PMC4659505 DOI: 10.1016/j.freeradbiomed.2015.06.021] [Citation(s) in RCA: 584] [Impact Index Per Article: 64.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 06/09/2015] [Accepted: 06/10/2015] [Indexed: 12/11/2022]
Abstract
UNLABELLED Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) regulates the basal and stress-inducible expression of a battery of genes encoding key components of the glutathione-based and thioredoxin-based antioxidant systems, as well as aldo-keto reductase, glutathione S-transferase, and NAD(P)H quinone oxidoreductase-1 drug-metabolizing isoenzymes along with multidrug-resistance-associated efflux pumps. It therefore plays a pivotal role in both intrinsic resistance and cellular adaptation to reactive oxygen species (ROS) and xenobiotics. Activation of Nrf2 can, however, serve as a double-edged sword because some of the genes it induces may contribute to chemical carcinogenesis by promoting futile redox cycling of polycyclic aromatic hydrocarbon metabolites or confer resistance to chemotherapeutic drugs by increasing the expression of efflux pumps, suggesting its cytoprotective effects will vary in a context-specific fashion. In addition to cytoprotection, Nrf2 also controls genes involved in intermediary metabolism, positively regulating those involved in NADPH generation, purine biosynthesis, and the β-oxidation of fatty acids, while suppressing those involved in lipogenesis and gluconeogenesis. Nrf2 is subject to regulation at multiple levels. Its ability to orchestrate adaptation to oxidants and electrophiles is due principally to stress-stimulated modification of thiols within one of its repressors, the Kelch-like ECH-associated protein 1 (Keap1), which is present in the cullin-3 RING ubiquitin ligase (CRL) complex CRLKeap1. Thus modification of Cys residues in Keap1 blocks CRLKeap1 activity, allowing newly translated Nrf2 to accumulate rapidly and induce its target genes. The ability of Keap1 to repress Nrf2 can be attenuated by p62/sequestosome-1 in a mechanistic target of rapamycin complex 1 (mTORC1)-dependent manner, thereby allowing refeeding after fasting to increase Nrf2-target gene expression. In parallel with repression by Keap1, Nrf2 is also repressed by β-transducin repeat-containing protein (β-TrCP), present in the Skp1-cullin-1-F-box protein (SCF) ubiquitin ligase complex SCFβ-TrCP. The ability of SCFβ-TrCP to suppress Nrf2 activity is itself enhanced by prior phosphorylation of the transcription factor by glycogen synthase kinase-3 (GSK-3) through formation of a DSGIS-containing phosphodegron. However, formation of the phosphodegron in Nrf2 by GSK-3 is inhibited by stimuli that activate protein kinase B (PKB)/Akt. In particular, PKB/Akt activity can be increased by phosphoinositide 3-kinase and mTORC2, thereby providing an explanation of why antioxidant-responsive element-driven genes are induced by growth factors and nutrients. Thus Nrf2 activity is tightly controlled via CRLKeap1 and SCFβ-TrCP by oxidative stress and energy-based signals, allowing it to mediate adaptive responses that restore redox homeostasis and modulate intermediary metabolism. Based on the fact that Nrf2 influences multiple biochemical pathways in both positive and negative ways, it is likely its dose-response curve, in terms of susceptibility to certain degenerative disease, is U-shaped. Specifically, too little Nrf2 activity will lead to loss of cytoprotection, diminished antioxidant capacity, and lowered β-oxidation of fatty acids, while conversely also exhibiting heightened sensitivity to ROS-based signaling that involves receptor tyrosine kinases and apoptosis signal-regulating kinase-1. By contrast, too much Nrf2 activity disturbs the homeostatic balance in favor of reduction, and so may have deleterious consequences including overproduction of reduced glutathione and NADPH, the blunting of ROS-based signal transduction, epithelial cell hyperplasia, and failure of certain cell types to differentiate correctly. We discuss the basis of a putative U-shaped Nrf2 dose-response curve in terms of potentially competing processes relevant to different stages of tumorigenesis.
Collapse
Affiliation(s)
- Lauren E Tebay
- Jacqui Wood Cancer Centre, Division of Cancer Research, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK
| | - Holly Robertson
- Jacqui Wood Cancer Centre, Division of Cancer Research, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK
| | - Stephen T Durant
- AstraZeneca Oncology Innovative Medicines, Bioscience, 33F197 Mereside, Alderley Park, Cheshire SK10 4TG, UK
| | - Steven R Vitale
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-6160, USA
| | - Trevor M Penning
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-6160, USA
| | - Albena T Dinkova-Kostova
- Jacqui Wood Cancer Centre, Division of Cancer Research, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK
| | - John D Hayes
- Jacqui Wood Cancer Centre, Division of Cancer Research, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK.
| |
Collapse
|
9
|
Erić S, Kalinić M, Ilić K, Zloh M. Computational classification models for predicting the interaction of drugs with P-glycoprotein and breast cancer resistance protein. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2014; 25:939-966. [PMID: 25435255 DOI: 10.1080/1062936x.2014.976265] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 08/13/2014] [Indexed: 06/04/2023]
Abstract
P-glycoprotein (P-gp/ABCB1) and breast cancer resistance protein (BCRP/ABCG2) are two members of the adenosine triphosphate (ATP) binding cassette (ABC) family of transporters which function as membrane efflux transporters and display considerable substrate promiscuity. Both are known to significantly influence the absorption, distribution and elimination of drugs, mediate drug-drug interactions and contribute to multiple drug resistance (MDR) of cancer cells. Correspondingly, timely characterization of the interaction of novel leads and drug candidates with these two transporters is of great importance. In this study, several computational classification models for prediction of transport and inhibition of P-gp and BCRP, respectively, were developed based on newly compiled and critically evaluated experimental data. Artificial neural network (ANN) and support vector machine (SVM) ensemble based models were explored, as well as knowledge-based approaches to descriptor selection. The average overall classification accuracy of best performing models was 82% for P-gp transport, 88% for BCRP transport, 89% for P-gp inhibition and 87% for BCRP inhibition, determined across an array of different test sets. An analysis of substrate overlap between P-gp and BCRP was also performed. The accuracy, simplicity and interpretability of the proposed models suggest that they could be of significant utility in the drug discovery and development settings.
Collapse
Affiliation(s)
- S Erić
- a Department of Pharmaceutical Chemistry , University of Belgrade , Belgrade , Serbia
| | | | | | | |
Collapse
|
10
|
Nickel S, Mahringer A. The xenoestrogens ethinylestradiol and bisphenol A regulate BCRP at the blood-brain barrier of rats. Xenobiotica 2014; 44:1046-54. [PMID: 24945792 DOI: 10.3109/00498254.2014.922226] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
1. Breast cancer resistance protein (BCRP) is an ABC-transporter at the blood-brain barrier (BBB) facilitating efflux of xenobiotics into blood. Expression and function are regulated via estrogen-receptors (ERs). 2. 17α-Ethinylestradiol (EE2) and bisphenol A (BPA) represent two prominent xenoestrogens. We studied whether EE2 and BPA regulate BCRP function and expression upon a 6 h treatment in an ER-dependent manner in a rat BBB-ex-vivo-model. 3. Isolated brain capillaries were incubated with EE2 or BPA. BCRP function and expression were analyzed by confocal microscopy and Western-Blot. ERα-antagonist MPP and ER-antagonist ICI182.780 were used to study involvement of ERs. 4. EE2 and BPA down-regulated BCRP transport function and expression. EE2 effects occurred at pharmacologically relevant doses, BPA exhibited only weak influences. Down-regulation by EE2 was reversed by ICI but not MPP. BPA effects were not reversed by either antagonist. 5. EE2 is a potent regulator of BCRP expression and function acting by ERβ-stimulation. Oral contraception could alter uptake of pharmaceuticals to the brain and might thus be considered as an origin of central nervous system (CNS) side-effects. EE2 could also present a novel co-treatment to improve CNS-pharmacotherapy. BPA is a weak modulator of BCRP expression. Its effects appear not to be caused by ERs.
Collapse
Affiliation(s)
- Sabrina Nickel
- Department of Pharmaceutical Technology and Biopharmaceutics, Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg , Heidelberg , Germany
| | | |
Collapse
|
11
|
Deppe S, Ripperger A, Weiss J, Ergün S, Benndorf RA. Impact of genetic variability in the ABCG2 gene on ABCG2 expression, function, and interaction with AT1 receptor antagonist telmisartan. Biochem Biophys Res Commun 2014; 443:1211-7. [PMID: 24388985 DOI: 10.1016/j.bbrc.2013.12.119] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 12/22/2013] [Indexed: 12/31/2022]
Abstract
The ATP-binding cassette transporter ABCG2 plays a prominent role in cardiovascular and cancer pathophysiology, is involved in the pathogenesis of gout, and affects pharmacokinetics of numerous drugs. Telmisartan, a widely used AT1 receptor antagonist, inhibits the transport capacity of ABCG2 and may cause drug-drug interactions, especially in individuals carrying polymorphism that facilitate the telmisartan-ABCG2 interaction. Thus, the aim of this study was to identify ABCG2 polymorphisms and somatic mutations with relevance for the telmisartan-ABCG2 interaction. For this purpose, a cellular system for the conditional expression of ABCG2 was established. ABCG2 variants were generated via site-directed mutagenesis. Interaction of telmisartan with these ABCG2 variants was investigated in HEK293-Tet-On cells using the pheophorbide A efflux assay. Moreover, expression of ABCG2 variants was studied in these cells. Importantly, protein levels of the Q141K and F489L variant were significantly reduced, a phenomenon that was partly reversed by pharmacological proteasome inhibition. Moreover, basal pheophorbide A efflux capacity of S248P, F431L, and F489L variants was significantly impaired. Interestingly, inhibition of ABCG2-mediated pheophorbide A transport by telmisartan was almost abolished in cells expressing the R482G variant, whereas it was largely increased in cells expressing the F489L variant. We conclude that the arginine residue at position 482 of the ABCG2 molecule is of major importance for the interaction of telmisartan with this ABC transporter. Furthermore, individuals carrying the F489L polymorphism may be at increased risk of developing adverse drug reactions in multi-drug regimens involving ABCG2 substrates and telmisartan.
Collapse
Affiliation(s)
- Sylvia Deppe
- Technical University of Braunschweig, Institute of Pharmacology, Toxicology, and Clinical Pharmacy, Braunschweig, Germany
| | - Anne Ripperger
- Martin-Luther-University Halle-Wittenberg, Department of Clinical Pharmacy and Pharmacotherapy, Halle (Saale), Germany
| | - Johanna Weiss
- Department of Clinical Pharmacology and Pharmacoepidemiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Süleyman Ergün
- Julius-Maximilians-Universität Würzburg, Institute of Anatomy and Cell Biology, Würzburg, Germany
| | - Ralf A Benndorf
- Martin-Luther-University Halle-Wittenberg, Department of Clinical Pharmacy and Pharmacotherapy, Halle (Saale), Germany.
| |
Collapse
|
12
|
Pfeifer ND, Hardwick RN, Brouwer KLR. Role of hepatic efflux transporters in regulating systemic and hepatocyte exposure to xenobiotics. Annu Rev Pharmacol Toxicol 2013; 54:509-35. [PMID: 24160696 DOI: 10.1146/annurev-pharmtox-011613-140021] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Hepatic efflux transporters include numerous well-known and emerging proteins localized to the canalicular or basolateral membrane of the hepatocyte that are responsible for the excretion of drugs into the bile or blood, respectively. Altered function of hepatic efflux transporters due to drug-drug interactions, genetic variation, and/or disease states may lead to changes in xenobiotic exposure in the hepatocyte and/or systemic circulation. This review focuses on transport proteins involved in the hepatocellular efflux of drugs and metabolites, discusses mechanisms of altered transporter function as well as the interplay between multiple transport pathways, and highlights the importance of considering intracellular unbound concentrations of transporter substrates and/or inhibitors. Methods to evaluate hepatic efflux transport and predict the effects of impaired transporter function on systemic and hepatocyte exposure are discussed, and the sandwich-cultured hepatocyte model to evaluate comprehensively the role of hepatic efflux in the hepatobiliary disposition of xenobiotics is characterized.
Collapse
Affiliation(s)
- Nathan D Pfeifer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599; ,
| | | | | |
Collapse
|
13
|
Yang Q, Li M, Wang T, Xu H, Zang W, Zhao G. Effect of STAT5 silenced by siRNA on proliferation apoptosis and invasion of esophageal carcinoma cell line Eca-109. Diagn Pathol 2013; 8:132. [PMID: 23915238 PMCID: PMC3751209 DOI: 10.1186/1746-1596-8-132] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 07/23/2013] [Indexed: 01/26/2023] Open
Abstract
Background STAT is the backward position of cytokine and growth factor receptors in the nucleus, STAT dimers could bind to DNA and induce transcription of specific target genes. Several lines of evidence support the important roles of STAT, especially STAT5, in carcinogenesis. The overexpression of STAT 5 is related to the differentiation and apoptosis of tumor cells. However, the role of STAT5 in esophageal squamous cell carcinoma remains unclear. Methods The siRNA vectors aiming to STAT5 gene were constructed. STAT5 siRNA was transfected into Eca-109 cells by Lipofectamine™2000. Expression of STAT5、Bcl-2 and Cyclin D1 were analyzed by Western blot and RT-PCR. Eca-109 cells proliferation was determined by MTT. Eca-109 cell cycle and apoptosis were detected by the flow cytometry. Boyden chamber was used to evaluate the invasion and metastasis capabilities of Eca-109 cells. Results The double strands oligonucleotide of siRNA aiming to STAT5 was successfully cloned into the pRNAT-U6.1 vector, and the target sequence coincided with the design. RT-PCR and Western blotting detection demonstrated that the expression levels of STAT5、Bcl-2 and Cyclin D1 gene were obviously decreased in Eca-109 cells transfected with STAT5 siRNA. STAT5 siRNA could suppress the proliferation of Eca-109 cells. The proportion of S and G2/M period frequency was significantly decreased (p < 0.05). The proportion of G0/G1 period frequency was significantly increased (p < 0.05). The average amount of cells penetrating Matrigel was significantly decreased (p < 0.05). Conclusions STAT5 silenced by siRNA could induce the apoptosis and suppress the proliferation、invasion and metastasis of esophageal carcinoma cell line Eca-109, which indicated STAT5 might be a novel therapeutic strategy for the human ESCC. Virtual slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1351913072103000
Collapse
Affiliation(s)
- Qian Yang
- Medical Examination Center, The First Affiliated Hospital of Henan University of TCM, Zhengzhou, People’s Republic of China
| | | | | | | | | | | |
Collapse
|
14
|
Abbott NJ. Blood-brain barrier structure and function and the challenges for CNS drug delivery. J Inherit Metab Dis 2013; 36:437-49. [PMID: 23609350 DOI: 10.1007/s10545-013-9608-0] [Citation(s) in RCA: 530] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 04/02/2013] [Accepted: 04/03/2013] [Indexed: 12/12/2022]
Abstract
The neurons of the central nervous system (CNS) require precise control of their bathing microenvironment for optimal function, and an important element in this control is the blood-brain barrier (BBB). The BBB is formed by the endothelial cells lining the brain microvessels, under the inductive influence of neighbouring cell types within the 'neurovascular unit' (NVU) including astrocytes and pericytes. The endothelium forms the major interface between the blood and the CNS, and by a combination of low passive permeability and presence of specific transport systems, enzymes and receptors regulates molecular and cellular traffic across the barrier layer. A number of methods and models are available for examining BBB permeation in vivo and in vitro, and can give valuable information on the mechanisms by which therapeutic agents and constructs permeate, ways to optimize permeation, and implications for drug discovery, delivery and toxicity. For treating lysosomal storage diseases (LSDs), models can be included that mimic aspects of the disease, including genetically-modified animals, and in vitro models can be used to examine the effects of cells of the NVU on the BBB under pathological conditions. For testing CNS drug delivery, several in vitro models now provide reliable prediction of penetration of drugs including large molecules and artificial constructs with promising potential in treating LSDs. For many of these diseases it is still not clear how best to deliver appropriate drugs to the CNS, and a concerted approach using a variety of models and methods can give critical insights and indicate practical solutions.
Collapse
Affiliation(s)
- N Joan Abbott
- BBB Group, Institute of Pharmaceutical Science, King's College London, London, UK.
| |
Collapse
|
15
|
Zhang D, Frost CE, He K, Rodrigues AD, Wang X, Wang L, Goosen TC, Humphreys WG. Investigating the Enteroenteric Recirculation of Apixaban, a Factor Xa Inhibitor: Administration of Activated Charcoal to Bile Duct-Cannulated Rats and Dogs Receiving an Intravenous Dose and Use of Drug Transporter Knockout Rats. Drug Metab Dispos 2013; 41:906-15. [DOI: 10.1124/dmd.112.050575] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
|
16
|
Zhang D, He K, Herbst JJ, Kolb J, Shou W, Wang L, Balimane PV, Han YH, Gan J, Frost CE, Humphreys WG. Characterization of efflux transporters involved in distribution and disposition of apixaban. Drug Metab Dispos 2013; 41:827-35. [PMID: 23382458 DOI: 10.1124/dmd.112.050260] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The studies reported here were conducted to investigate the transport characteristics of apixaban (1-(4-methoxyphenyl)-7-oxo-6-(4-(2-oxopiperidin-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide) and to understand the impact of transporters on apixaban distribution and disposition. In human permeability glycoprotein (P-gp)- and breast cancer resistance protein (BCRP)-cDNA-transfected cell monolayers as well as Caco-2 cell monolayers, the apparent efflux ratio of basolateral-to-apical (PcB-A) versus apical-to-basolateral permeability (PcA-B) of apixaban was >10. The P-gp- and BCRP-facilitated transport of apixaban was concentration- and time-dependent and did not show saturation over a wide range of concentrations (1-100 μM). The efflux transport of apixaban was also demonstrated by the lower mucosal-to-serosal permeability than that of the serosal-to-mucosal direction in isolated rat jejunum segments. Apixaban did not inhibit digoxin transport in Caco-2 cells. Ketoconazole decreased the P-gp-mediated apixaban efflux in Caco-2 and the P-gp-cDNA-transfected cell monolayers, but did not affect the apixaban efflux to a meaningful extent in the BCRP-cDNA-transfected cell monolayers. Coincubation of a P-gp inhibitor (ketoconazole or cyclosporin A) and a BCRP inhibitor (Ko134) provided more complete inhibition of apixaban efflux in Caco-2 cells than separate inhibition by individual inhibitors. Naproxen inhibited apixaban efflux in Caco-2 cells but showed only a minimal effect on apixaban transport in the BCRP-transfected cells. Naproxen was the first nonsteroidal antiinflammatory drug that was demonstrated as a weak P-gp inhibitor. These results demonstrate that apixaban is a substrate for efflux transporters P-gp and BCRP, which can help explain its low brain penetration, and low fetal exposures and high milk excretion in rats.
Collapse
Affiliation(s)
- Donglu Zhang
- Pharmaceutical Candidate Optimization, Bristol-Myers Squibb, Princeton, New Jersey 08543, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Huang L, Lu Q, Han Y, Li Z, Zhang Z, Li X. ABCG2/V-ATPase was associated with the drug resistance and tumor metastasis of esophageal squamous cancer cells. Diagn Pathol 2012; 7:180. [PMID: 23244569 PMCID: PMC3542252 DOI: 10.1186/1746-1596-7-180] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 12/11/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND ATP-binding cassette sub-family G member 2 (ABCG2) is a protein that in humans is encoded by the ABCG2 gene. ABCG2 participates in efflux of many chemotherapeutic agents. ABCG2 is often expressed in hematopoietic progenitor or stem cells. Vacuolar-H + -ATPase (V-ATPase) plays a key role in adjusting and maintaining intracellular pH and in regulating the drug tolerance of cells. The TNM Classification of Malignant Tumours (TNM) is a cancer staging system that describes the extent of cancer in a patient's body. In this study, the expression of ABCG2 and V-ATPase in esophageal squamous cancer cells was detected. METHODS Immunohistochemistry staining and Immunofluorescence double staining were used to detect the expression of ABCG2 and V-ATPase in in 66 cases of esophageal squamous cancer cells. Associations and differences in expression of ABCG2 with that of V-ATPase were analyzed. RESULTS Positive staining patterns for both ABCG2 (66.67%) and V-ATPase (68.18%) were located mainly in the plasma membrane and cytoplasm. Marked differences in expression were also shown (P < 0.001) among 3 groups of pathological grades and TNM stages in these carcinomas. Marked differences were also found for ABCG2 expression between the two groups in the pathological grades and in the TNM staging groups (P < 0.01), but not between the αb and βgroups. V-ATPase expression was statistically significant between the 2 groups in the pathological grades and TNM stages (P < 0.05). This was not evident between α and β groups of pathological grades or between αb and βof the TNM stages. Marked differences in expression of ABCG2 and V-ATPase were found between metastatic and non-metastatic groups in the same carcinomas (P < 0.0001). There was also a clear correlation between the expression of ABCG2 and V-ATPase (P ≤ 0.001) in the various groups of pathological grades and TNM stages. CONCLUSIONS Both ABCG2 and V-ATPase were over-expressed in esophageal squamous cancer cells. Their expression was associated with pathological grade, TNM stage and tumor metastasis in esophageal squamous cancer cells, suggesting interaction relationship between them. ABCG2 and V-ATPase expression may be strongly associated with drug resistance and tumor metastasis. VIRTUAL SLIDES The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/3823783918433897.
Collapse
Affiliation(s)
- Lijun Huang
- Department of Thoracic Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, People's Republic of China
| | | | | | | | | | | |
Collapse
|
18
|
Abstract
The blood-testis barrier (BTB) is one of the tightest blood-tissue barriers in the mammalian body. It divides the seminiferous epithelium into the basal and the apical (adluminal) compartments. Meiosis I and II, spermiogenesis, and spermiation all take place in a specialized microenvironment behind the BTB in the apical compartment, but spermatogonial renewal and differentiation and cell cycle progression up to the preleptotene spermatocyte stage take place outside of the BTB in the basal compartment of the epithelium. However, the BTB is not a static ultrastructure. Instead, it undergoes extensive restructuring during the seminiferous epithelial cycle of spermatogenesis at stage VIII to allow the transit of preleptotene spermatocytes at the BTB. Yet the immunological barrier conferred by the BTB cannot be compromised, even transiently, during the epithelial cycle to avoid the production of antibodies against meiotic and postmeiotic germ cells. Studies have demonstrated that some unlikely partners, namely adhesion protein complexes (e.g., occludin-ZO-1, N-cadherin-β-catenin, claudin-5-ZO-1), steroids (e.g., testosterone, estradiol-17β), nonreceptor protein kinases (e.g., focal adhesion kinase, c-Src, c-Yes), polarity proteins (e.g., PAR6, Cdc42, 14-3-3), endocytic vesicle proteins (e.g., clathrin, caveolin, dynamin 2), and actin regulatory proteins (e.g., Eps8, Arp2/3 complex), are working together, apparently under the overall influence of cytokines (e.g., transforming growth factor-β3, tumor necrosis factor-α, interleukin-1α). In short, a "new" BTB is created behind spermatocytes in transit while the "old" BTB above transiting cells undergoes timely degeneration, so that the immunological barrier can be maintained while spermatocytes are traversing the BTB. We also discuss recent findings regarding the molecular mechanisms by which environmental toxicants (e.g., cadmium, bisphenol A) induce testicular injury via their initial actions at the BTB to elicit subsequent damage to germ-cell adhesion, thereby leading to germ-cell loss, reduced sperm count, and male infertility or subfertility. Moreover, we also critically evaluate findings in the field regarding studies on drug transporters in the testis and discuss how these influx and efflux pumps regulate the entry of potential nonhormonal male contraceptives to the apical compartment to exert their effects. Collectively, these findings illustrate multiple potential targets are present at the BTB for innovative contraceptive development and for better delivery of drugs to alleviate toxicant-induced reproductive dysfunction in men.
Collapse
Affiliation(s)
- C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA.
| | | |
Collapse
|
19
|
Abstract
ATP-binding cassette (ABC) transporters form a large family of transmembrane proteins that facilitate the transport of specific substrates across membranes in an ATP-dependent manner. Transported substrates include lipids, lipopolysaccharides, amino acids, peptides, proteins, inorganic ions, sugars and xenobiotics. Despite this broad array of substrates, the physiological substrate of many ABC transporters has remained elusive. ABC transporters are divided into seven subfamilies, A-G, based on sequence similarity and domain organization. Here we review the role of members of the ABCG subfamily in human disease and how the identification of disease genes helped to determine physiological substrates for specific ABC transporters. We focus on the recent discovery of mutations in ABCG2 causing hyperuricemia and gout, which has led to the identification of urate as a physiological substrate for ABCG2.
Collapse
Affiliation(s)
- Owen M Woodward
- Department of Physiology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | | | | |
Collapse
|
20
|
Lebedeva IV, Pande P, Patton WF. Sensitive and specific fluorescent probes for functional analysis of the three major types of mammalian ABC transporters. PLoS One 2011; 6:e22429. [PMID: 21799851 PMCID: PMC3142157 DOI: 10.1371/journal.pone.0022429] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 06/23/2011] [Indexed: 11/18/2022] Open
Abstract
An underlying mechanism for multi drug resistance (MDR) is up-regulation of the transmembrane ATP-binding cassette (ABC) transporter proteins. ABC transporters also determine the general fate and effect of pharmaceutical agents in the body. The three major types of ABC transporters are MDR1 (P-gp, P-glycoprotein, ABCB1), MRP1/2 (ABCC1/2) and BCRP/MXR (ABCG2) proteins. Flow cytometry (FCM) allows determination of the functional expression levels of ABC transporters in live cells, but most dyes used as indicators (rhodamine 123, DiOC2(3), calcein-AM) have limited applicability as they do not detect all three major types of ABC transporters. Dyes with broad coverage (such as doxorubicin, daunorubicin and mitoxantrone) lack sensitivity due to overall dimness and thus may yield a significant percentage of false negative results. We describe two novel fluorescent probes that are substrates for all three common types of ABC transporters and can serve as indicators of MDR in flow cytometry assays using live cells. The probes exhibit fast internalization, favorable uptake/efflux kinetics and high sensitivity of MDR detection, as established by multidrug resistance activity factor (MAF) values and Kolmogorov-Smirnov statistical analysis. Used in combination with general or specific inhibitors of ABC transporters, both dyes readily identify functional efflux and are capable of detecting small levels of efflux as well as defining the type of multidrug resistance. The assay can be applied to the screening of putative modulators of ABC transporters, facilitating rapid, reproducible, specific and relatively simple functional detection of ABC transporter activity, and ready implementation on widely available instruments.
Collapse
Affiliation(s)
- Irina V Lebedeva
- ENZO Life Sciences, Inc., Farmingdale, New York, United States of America.
| | | | | |
Collapse
|
21
|
Do TM, Ouellet M, Calon F, Chimini G, Chacun H, Farinotti R, Bourasset F. Direct evidence of abca1-mediated efflux of cholesterol at the mouse blood-brain barrier. Mol Cell Biochem 2011; 357:397-404. [PMID: 21660464 DOI: 10.1007/s11010-011-0910-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 05/28/2011] [Indexed: 02/07/2023]
Abstract
We investigated the expression and function of Abca1 in wild-type C57BL/6, abca1(+/+), and abca1(-/-) mice brain capillaries forming the blood-brain barrier (BBB). We first demonstrated by quantitative RT-PCR and Western immunoblot that Abca1 was expressed and enriched in the wild-type mouse brain capillaries. In abca1(-/-) mice, we reported that the lack of Abca1 resulted in an 1.6-fold increase of the Abcg4 expression level compared to abca1(+/+) mice. Next, using the in situ brain perfusion technique, we showed that the [(3)H]cholesterol brain uptake clearance (Cl(up), μl/s/g brain), was significantly increased (107%) in abca1(-/-) mice compared to abca1(+/+) mice, meaning that the deficiency of Abca1 conducted to a significant decrease of the cholesterol efflux at the BBB level. In addition, the co-perfusion of probucol (Abca1 inhibitor) with [(3)H]cholesterol resulted in an increase of [(3)H]cholesterol Cl(up) (115%) in abca1(+/+) but not in abca1(-/-) mice, meaning that probucol inhibited selectively the efflux function of Abca1. In conclusion, our results demonstrated that Abca1 was expressed in the mouse brain capillaries and that Abca1 functions as an efflux transporter through the mouse BBB.
Collapse
Affiliation(s)
- Tuan Minh Do
- Laboratory of Clinical Pharmacy, EA4123, University of Paris Sud 11, 5 rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France
| | | | | | | | | | | | | |
Collapse
|
22
|
Abstract
The blood-testis barrier (BTB), which is created by adjacent Sertoli cells near the basement membrane, serves as a 'gatekeeper' to prohibit harmful substances from reaching developing germ cells, most notably postmeiotic spermatids. The BTB also divides the seminiferous epithelium into the basal and adluminal (apical) compartment so that postmeiotic spermatid development, namely spermiogenesis, can take place in a specialized microenvironment in the apical compartment behind the BTB. The BTB also contributes, at least in part, to the immune privilege status of the testis, so that anti-sperm antibodies are not developed against antigens that are expressed transiently during spermatogenesis. Recent studies have shown that numerous drug transporters are expressed by Sertoli cells. However, many of these same drug transporters are also expressed by spermatogonia, spermatocytes, round spermatids, elongating spermatids, and elongated spermatids, suggesting that the developing germ cells are also able to selectively pump drugs 'in' and/or 'out' via influx or efflux pumps. We review herein the latest developments regarding the role of drug transporters in spermatogenesis. We also propose a model utilized by the testis to protect germ cell development from 'harmful' environmental toxicants and xenobiotics and/or from 'therapeutic' substances (e.g. anticancer drugs). We also discuss how drug transporters that are supposed to protect spermatogenesis can work against the testis in some instances. For example, when drugs (e.g. male contraceptives) that can perturb germ cell adhesion and/or maturation are actively pumped out of the testis or are prevented from entering the apical compartment, such as by efflux pumps.
Collapse
Affiliation(s)
- Linlin Su
- The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York 10065, USA
| | | | | |
Collapse
|
23
|
Giraud C, Manceau S, Treluyer JM. ABC transporters in human lymphocytes: expression, activity and role, modulating factors and consequences for antiretroviral therapies. Expert Opin Drug Metab Toxicol 2010; 6:571-89. [PMID: 20367109 DOI: 10.1517/17425251003601953] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
IMPORTANCE OF THE FIELD ATP-binding cassette (ABC) transporters are a superfamily of efflux pumps that transport numerous compounds across cell membranes. These transporters are located in various human tissues including peripheral blood cells, in particular lymphocytes, and present a high variability of expression and activity. This variability may affect the intracellular concentrations and efficacy of drugs acting within lymphocytes, such as antiretroviral drugs. AREAS COVERED IN THIS REVIEW This review focuses on the current knowledge about the expression, activity, roles and variability of ABC drug transporters in human lymphocytes. The identified modulating factors and their impact on the intracellular pharmacokinetics and efficacy of antiretroviral drugs are also detailed. WHAT THE READER WILL GAIN Controversial data regarding the expression, activity and sources of variability of ABC transporters in lymphocytes are discussed. The modulating factors and their pharmacological consequences regarding antiretroviral therapies are also provided. TAKE HOME MESSAGE Numerous studies have reported conflicting results regarding the expression and activity of ABC drug transporters in lymphocytes. Despite these discrepancies, which may partly result from heterogeneous analytical methods, ABCC1 appears to have the highest expression in lymphocytes and may thus play a predominant role in the resistance to antiretroviral drugs, particularly to protease inhibitors.
Collapse
Affiliation(s)
- Carole Giraud
- Groupe Hospitalier Cochin - Saint-Vincent-de-Paul, Assistance Publique - Hôpitaux de Paris, Centre de Recherche Clinique Paris Descartes, Site Hôpital Tarnier, 89 rue d'Assas, 75006 Paris, France.
| | | | | |
Collapse
|
24
|
Mennone A, Soroka CJ, Harry KM, Boyer JL. Role of breast cancer resistance protein in the adaptive response to cholestasis. Drug Metab Dispos 2010; 38:1673-8. [PMID: 20601550 DOI: 10.1124/dmd.110.034512] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Breast cancer resistance protein (Bcrp) is a member of the ATP-binding cassette membrane transporter family, which is expressed apically in liver, kidney, and intestine epithelium. Recent reports suggest that in addition to xenobiotics, porphyrins, and food toxins, Bcrp can also transport bile acids and, therefore, may participate in the adaptive response to cholestasis. Bile duct ligation (BDL), an experimental model of obstructive cholestasis, was performed in male wild-type (WT) and Bcrp knockout (KO) mice. An initial time course of 3, 7, and 14 days of BDL in WT mice revealed that Bcrp expression was significantly reduced in liver but increased in ileum by 7 days. Subsequent experiments using 7-day BDL in WT and Bcrp KO mice demonstrated that there was no difference in liver necrosis, serum glutamic pyruvate aminotransferase, bilirubin, or bile acid levels in serum, hepatic tissue, bile, urine, or feces between the two groups. Protein expression levels for liver organic solute transporter (Ost) α and multidrug resistance protein 1 and kidney multidrug resistance-associated protein (Mrp) 2, Mrp3, and Mrp4 were significantly greater in the sham Bcrp KO versus sham WT mice. The expression of Mrp2 and Mrp4 in KO kidneys was further increased after BDL. In contrast, the adaptive response of transporters to BDL in the liver was similar in KO and WT BDL mice, including Ostα and Ostβ expression, which increased in liver and kidney but decreased in the ileum. These findings suggest that Bcrp does not have a significant role in the adaptive response to cholestasis in the liver but may be more important for solute export in the kidney and intestine.
Collapse
Affiliation(s)
- Albert Mennone
- Department of Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8019, USA
| | | | | | | |
Collapse
|
25
|
Abstract
The blood-brain barrier (BBB) is a dynamic physical and biological barrier between blood circulation and the central nervous system (CNS). This unique feature of the BBB lies in the structure of the neurovascular unit and its cerebral micro-vascular endothelial cells. The BBB restricts the passage of blood-borne drugs, neurotoxic substances and peripheral immune cells from entering the brain, while selectively facilitating the transport of nutrients across the BBB into the brain. Thus, the integrity and proper function of the BBB is crucial to homeostasis and physiological function of the CNS. A number of transport and carrier systems are expressed and polarized on the luminal or abluminal surface of the BBB to realize these discrete functions. Among these systems, ABC transporters play a critical role in keeping drugs and neurotoxic substances from entering the brain and in transporting toxic metabolites out of the brain. A number of studies have demonstrated that ABCB1 and ABCG2 are critical to drug efflux at the BBB and that ABCC1 is essential for the blood-cerebral spinal fluid (CSF) barrier. The presence of these efflux ABC transporters also creates a major obstacle for drug delivery into the brain. We have comprehensively reviewed the literature on ABC transporters and drug efflux at the BBB. Understanding the molecular mechanisms of these transporters is important in the development of new drugs and new strategies for drug delivery into the brain.
Collapse
Affiliation(s)
- Shanshan Shen
- Neurobiology Program, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Canada K1A 0R6
| | | |
Collapse
|
26
|
Abstract
Breast cancer resistance protein (BCRP/ABCG2) was discovered in multidrug resistant breast cancer cells having an ATP-dependent transport-based resistance phenotype. This ABC transporter functions (at least in part) as a xenobiotic protective mechanism for the organism: in the gut and biliary tract, it prevents absorption and enhances elimination of potentially toxic substances. As a placental barrier, it protects the fetus; similarly, it serves as a component of blood-brain and blood-testis barrier; BCRP is expressed in stem cells and may protect them from potentially harmful agents. Therefore, BCRP could influence cancer outcomes by (a) endogenous BCRP affecting the absorption, distribution, metabolism, and elimination of anticancer drugs; (b) BCRP expression in cancer cells may directly cause resistance by active efflux of anticancer drugs; (c) BCRP expression in cancer cells could be a manifestation of the activity of metabolic and signaling pathways that impart multiple mechanisms of drug resistance, self-renewal (stemness), and invasiveness (aggressiveness)--i.e. impart a poor prognosis--to cancers. This chapter presents a synopsis of translational clinical studies relating BCRP expression in leukemias, lymphomas, and a variety of solid tumors with clinical outcome. Data are emerging that expression of BCRP, like P-glycoprotein/ABCB1, is associated with adverse outcomes in a variety of human cancers. Whether this adverse prognostic effect results from resistance imparted to the cancer cells as the direct result of BCRP efflux of anticancer drugs, or whether BCRP expression (and also Pgp expression - coexpression of these transporters is common among poor risk cancers) serves as indicators of the activity of signaling pathways that enhance cancer cellular proliferation, metastases, genomic instability, enhance drug resistance, and oppose programmed cell death mechanisms is yet unknown.
Collapse
Affiliation(s)
- Douglas D Ross
- University of Maryland Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore VA Medical Center, Baltimore, MD, USA.
| | | |
Collapse
|
27
|
Benedetti MS, Whomsley R, Poggesi I, Cawello W, Mathy FX, Delporte ML, Papeleu P, Watelet JB. Drug metabolism and pharmacokinetics. Drug Metab Rev 2009; 41:344-90. [PMID: 19601718 DOI: 10.1080/10837450902891295] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In this article, aspects of absorption, distribution, metabolism, and excretion have been described bearing in mind the pathogenesis of allergic diseases and their possible therapeutic opportunities. The importance of the routes of administration of the different therapeutic groups has been emphasized. The classical aspects of drug metabolism and disposition related to oral administration have been reviewed, but special emphasis has been given to intranasal, cutaneous, transdermal, and ocular administration as well as to the absorption and the subsequent bioavailability of drugs. Drug-metabolizing enzymes and transporters present in extrahepatic tissues, such as nasal mucosa and the respiratory tract, have been particularly discussed. As marketed antiallergic drugs include both racemates and enantiomers, aspects of stereoselective absorption, distribution, metabolism, and excretion have been discussed. Finally, a new and promising methodology, microdosing, has been presented, although it has not yet been applied to drugs used in the treatment of allergic diseases.
Collapse
|
28
|
|
29
|
Cellular phototoxicity evoked through the inhibition of human ABC transporter ABCG2 by cyclin-dependent kinase inhibitors in vitro. Pharm Res 2008; 26:449-58. [PMID: 18841444 DOI: 10.1007/s11095-008-9738-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 09/24/2008] [Indexed: 10/21/2022]
Abstract
PURPOSE The physiological importance of the human ATP-binding cassette (ABC) transporter ABCG2 has been recognized with regard to porphyrin-mediated photosensitivity. Functional impairment owing to inhibition of ABCG2 by drugs or its genetic polymorphisms may lead to the disruption of porphyrin homeostasis, which in turn causes cellular toxicity. MATERIALS AND METHODS We evaluated the impact on photosensitivity of the inhibition by cyclin-dependent kinase (CDK) inhibitors of ABCG2 function. For this purpose, we established new methods for photosensitivity assays by using Flp-In-293 cells and plasma membrane vesicles prepared from Sf9 insect cells. With the new methods, we subsequently tested CDK inhibitors, i.e., purvalanol A, WHI-P180, bohemine, roscovitine, and olomoucine. RESULTS Among CDK inhibitors tested, purvalanol A was found to be the most potent inhibitor (IC50=3.5 microM) for ABCG2-mediated hematoporphyrin transport. At a concentration of 2.5 microM, it evoked the photosensitivity of ABCG2-expressing Flp-In-293 cells treated with pheophorbide a. WHI-P180 moderately inhibited ABCG2 function, exhibiting weak phototoxicity. In contrast, the phototoxicity of bohemine, roscovitine, and olomoucine were minimal in our assay system. CONCLUSIONS It is suggested that the planar structure is an important factor for interactions with the active site of ABCG2. The present study provides a new approach to studying drug-induced phototoxicity in vitro.
Collapse
|