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Mehyar N, Mashhour A, Islam I, Gul S, Adedeji AO, Askar AS, Boudjelal M. Using in silico modelling and FRET-based assays in the discovery of novel FDA-approved drugs as inhibitors of MERS-CoV helicase. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2021; 32:51-70. [PMID: 33401979 DOI: 10.1080/1062936x.2020.1857437] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/25/2020] [Indexed: 06/12/2023]
Abstract
A Förster resonance energy transfer (FRET)-based assay was used to screen the FDA-approved compound library against the MERS-CoV helicase, an essential enzyme for virus replication within the host cell. Five compounds inhibited the helicase activity with submicromolar potencies (IC50, 0.73-1.65 µM) and ten compounds inhibited the enzyme with micromolar potencies (IC50, 19.6-502 µM). The molecular operating environment (MOE) was used to dock the identified inhibitors on the MERS-CoV helicase nucleotide binding. Strong inhibitors docked well in the nucleotide-binding site and established interactions with some of the essential residues. There was a reasonable correlation between the observed IC50 values and the MOE docking scores of the strong inhibitors (r 2 = 0.74), indicating the ability of the in silico docking model to predict the binding of strong inhibitors. In silico docking could be a useful complementary tool used with the FRET-based assay to predict new MERS-CoV helicase inhibitors. The identified inhibitors could potentially be used in the clinical development of new antiviral treatment for MERS-CoV and other coronavirus related diseases, including coronavirus disease 2019 (COVID-19).
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Affiliation(s)
- N Mehyar
- King Abdullah International Medical Research Centre, King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs , Riyadh, Saudi Arabia
| | - A Mashhour
- King Abdullah International Medical Research Centre, King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs , Riyadh, Saudi Arabia
| | - I Islam
- King Abdullah International Medical Research Centre, King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs , Riyadh, Saudi Arabia
| | - S Gul
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME - ScreeningPort , Hamburg, Germany
| | - A O Adedeji
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University , Glendale, Arizona, USA
| | - A S Askar
- King Abdullah International Medical Research Centre, King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs , Riyadh, Saudi Arabia
| | - M Boudjelal
- King Abdullah International Medical Research Centre, King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs , Riyadh, Saudi Arabia
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Yamasaki Y, Kobayashi K, Inaba A, Uehara D, Tojima H, Kakizaki S, Chiba K. Indirect activation of pregnane X receptor in the induction of hepatic CYP3A11 by high-dose rifampicin in mice. Xenobiotica 2017; 48:1098-1105. [PMID: 29095659 DOI: 10.1080/00498254.2017.1400128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Rifampicin (RIF), a typical ligand of human pregnane X receptor (PXR), powerfully induces the expression of cytochrome P450 3A4 (CYP3A4) in humans. Although it is thought that RIF is not a ligand of rodent PXR, treatment with high-dose RIF (e.g. more than 20 mg/kg) increases the expression of CYP3A in the mouse liver. In this study, we investigated whether the induction of CYP3A by high-dose RIF in the mouse liver is mediated via indirect activation of mouse PXR (mPXR). The results showed that high-dose RIF increased the expression of CYP3A11 and other PXR-target genes in the liver of wild-type mice but not PXR-knockout mice. However, the results of reporter gene and ligand-dependent assembly assays showed that RIF does not activate mPXR in a ligand-dependent manner. In addition, high-dose RIF stimulated nuclear accumulation of mPXR in the mouse liver, and geldanamycin and okadaic acid attenuated the induction of Cyp3a11 and other PXR-target genes in primary hepatocytes, suggesting that high-dose RIF triggers nuclear translocation of mPXR. In conclusion, the present study suggests that high-dose RIF stimulates nuclear translocation of mPXR in the liver of mice by indirect activation, resulting in the transactivation of Cyp3a11 and other PXR-target genes.
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Affiliation(s)
- Yuki Yamasaki
- a Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University , Chiba , Japan and
| | - Kaoru Kobayashi
- a Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University , Chiba , Japan and
| | - Asumi Inaba
- a Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University , Chiba , Japan and
| | - Daisuke Uehara
- b Division of Gastroenterology and Hepatology, Department of Internal Medicine, Graduate School of Medicine, Gunma University , Maebashi , Japan
| | - Hiroki Tojima
- b Division of Gastroenterology and Hepatology, Department of Internal Medicine, Graduate School of Medicine, Gunma University , Maebashi , Japan
| | - Satoru Kakizaki
- b Division of Gastroenterology and Hepatology, Department of Internal Medicine, Graduate School of Medicine, Gunma University , Maebashi , Japan
| | - Kan Chiba
- a Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University , Chiba , Japan and
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Moscovitz JE, Lin Z, Johnson N, Tu M, Goosen TC, Weng Y, Kalgutkar AS. Induction of human cytochrome P450 3A4 by the irreversible myeloperoxidase inactivator PF-06282999 is mediated by the pregnane X receptor. Xenobiotica 2017; 48:647-655. [PMID: 28685622 DOI: 10.1080/00498254.2017.1353163] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
1. 2-(6-(5-Chloro-2-methoxyphenyl)-4-oxo-2-thioxo-3,4-dihydropyrimidin-1(2H)-yl) acetamide (PF-06282999) is a member of the thiouracil class of irreversible inactivators of human myeloperoxidase enzyme and a candidate for the treatment of cardiovascular disease. PF-06282999 is an inducer of CYP3A4 mRNA and midazolam-1'-hydroxylase activity in human hepatocytes, which is consistent with PF-06282999-dose dependent decreases in mean maximal plasma concentrations (Cmax) and area under the plasma concentration time curve (AUC) of midazolam in humans following 14-day treatment with PF-06282999. 2. In the present study, the biochemical mechanism(s) of CYP3A4 induction by PF-06282999 was studied. Incubations in reporter cells indicated that PF-06282999 selectively activated human pregnane X receptor (PXR). Treatment of human HepaRG cells with PF-06282999 led to ∼14-fold induction in CYP3A4 mRNA and 5-fold increase in midazolam-1'-hydroxylase activity, which was nullified in PXR-knock out HepaRG cells. TaqMan® gene expression analysis of human hepatocytes treated with PF-06282999 and the prototypical PXR agonist rifampin demonstrated increases in mRNA for CYP3A4 and related CYPs that are regulated by PXR. 3. Docking studies using a published human PXR crystal structure provided insights into the molecular basis for PXR activation by PF-06282999. Implementation of PXR transactivation assays in a follow-on discovery campaign should aid in the identification of back-up compounds devoid of PXR activation and CYP3A4 induction liability.
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Affiliation(s)
| | - Zhiwu Lin
- b Medicine Design, Pfizer Inc , Groton , CT , USA
| | | | - Meihua Tu
- a Medicine Design, Pfizer Inc , Cambridge , MA , USA and
| | | | - Yan Weng
- a Medicine Design, Pfizer Inc , Cambridge , MA , USA and
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In Silico Prediction of hPXR Activators Using Structure-Based Pharmacophore Modeling. J Pharm Sci 2017; 106:1752-1759. [DOI: 10.1016/j.xphs.2017.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/21/2017] [Accepted: 03/06/2017] [Indexed: 11/30/2022]
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Panomvana D, Methaneethorn J, Vachirayonstien T. Correlation Between Elimination Parameters of Phenytoin and Carbamazepine in Patients with Epilepsy Receiving Both Drugs Concomitantly: A Preliminary Study. Pharmaceut Med 2017. [DOI: 10.1007/s40290-017-0182-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Development of a common carp (Cyprinus carpio) pregnane X receptor (cPXR) transactivation reporter assay and its activation by azole fungicides and pharmaceutical chemicals. Toxicol In Vitro 2017; 41:114-122. [PMID: 28259787 PMCID: PMC5484788 DOI: 10.1016/j.tiv.2017.02.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 02/22/2017] [Accepted: 02/27/2017] [Indexed: 12/27/2022]
Abstract
In mammals, the pregnane X receptor (PXR) is a transcription factor with a key role in regulating expression of several genes involved in drug biotransformation. PXR is present in fish and some genes known to be under its control can be up-regulated by mammalian PXR ligands. Despite this, direct involvement of PXR in drug biotransformation in fish has yet to be established. Here, the full length PXR sequence was cloned from carp (Cyprinus carpio) and used in a luciferase reporter assay to elucidate its role in xenobiotic metabolism in fish. A reporter assay for human PXR (hPXR) was also established to compare transactivation between human and carp (cPXR) isoforms. Rifampicin activated hPXR as expected, but not cPXR. Conversely, clotrimazole (CTZ) activated both isoforms and was more potent on cPXR, with an EC50 within the range of concentrations of CTZ measured in the aquatic environment. Responses to other azoles tested were similar between both isoforms. A range of pharmaceuticals tested either failed to activate, or were very weakly active, on the cPXR or hPXR. Overall, these results indicate that the cPXR may differ from the hPXR in its responses and/or sensitivity to induction by different environmental chemicals, with implications for risk assessment because of species differences.
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Amacher DE. The regulation of human hepatic drug transporter expression by activation of xenobiotic-sensing nuclear receptors. Expert Opin Drug Metab Toxicol 2016; 12:1463-1477. [PMID: 27548410 DOI: 10.1080/17425255.2016.1223626] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
INTRODUCTION If a drug is found to be an inducer of hepatic drug metabolizing enzymes via activation of nuclear receptors such as pregnane X receptor (PXR) or constitutive androstane receptor (CAR), it is likely that drug transporters regulated through these same receptors will be induced as well. This review highlights what is currently known about the molecular mechanisms that regulate transporter expression and where the research is directed. Areas covered: This review is focused on publications that describe the role of activated hepatic nuclear receptors in the subsequent regulation of drug uptake and/or efflux transporters following exposure to xenobiotics. Expert opinion: Many of the published studies on the role of nuclear receptors in the regulation of drug transporters involve non-human test animals. But due to species response differences, these associations are not always applicable to humans. For this reason, some relevant human in vitro models have been developed, such as primary or cryopreserved human hepatocytes, human liver slices, or HepG2 or HuH7 cell lines transiently or stably transfected with PXR expression and reporter constructs as well as in vivo models such as PXR-humanized mice. These human-relevant test systems will continue to be developed and applied for the testing of investigational drugs.
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Kameyama N, Kobayashi K, Shimizu S, Yamasaki Y, Endo M, Hashimoto M, Furihata T, Chiba K. Involvement of ESE-3, epithelial-specific ETS factor family member 3, in transactivation of the ABCB1 gene via pregnane X receptor in intestine-derived LS180 cells but not in liver-derived HepG2 cells. Drug Metab Pharmacokinet 2016; 31:340-348. [PMID: 27567379 DOI: 10.1016/j.dmpk.2016.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/26/2016] [Accepted: 05/25/2016] [Indexed: 01/18/2023]
Abstract
Pregnane X receptor (PXR) is involved in the transactivation of ABCB1 gene by rifampicin (RIF). However, we found that increase in ABCB1 mRNA by RIF was observed in LS180 cells but not in HepG2 cells. Since both cell lines expressed PXR equally, we hypothesized that a factor(s) other than PXR is responsible for PXR-mediated transactivation of the ABCB1 gene. Reporter activities of a distal enhancer module containing direct repeat 4 (DR4) motifs were increased by RIF in LS180 cells but not in HepG2 cells. Mutation of the DR4 motifs diminished the increase in reporter activities in LS180 cells. Gene subtraction showed that epithelial-specific ETS factor 3 (ESE-3) is a transcription factor enriched in LS180 cells compared to HepG2 cells. When ESE-3 and PXR were co-expressed in HepG2 cells, reporter activities were increased by RIF, which were completely abolished by mutation of DR4 motifs. Chromatin immunoprecipitation assays showed specific binding of ESE-3 to the region containing the DR4 motifs of the ABCB1 gene. Finally, knock-down of ESE-3 in LS180 cells resulted in a decrease in the induction of ABCB1 mRNA. These results suggest that ESE-3 is a factor responsible for PXR-mediated transactivation of the ABCB1 gene by RIF in LS180 cells.
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Affiliation(s)
- Naoya Kameyama
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Kaoru Kobayashi
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
| | - Shoko Shimizu
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Yuki Yamasaki
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Mika Endo
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Mari Hashimoto
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Tomomi Furihata
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Kan Chiba
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
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Ma SL, Joung JY, Lee S, Cho KH, No KT. PXR ligand classification model with SFED-weighted WHIM and CoMMA descriptors. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2012; 23:485-504. [PMID: 22591167 DOI: 10.1080/1062936x.2012.665385] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Understanding which type of endogenous and exogenous compounds serve as agonists for the nuclear pregnane X receptor (PXR) would be valuable for drug discovery and development, because PXR regulates a large number of genes related to xenobiotic metabolism. Although several models have been proposed to classify human PXR activators and non-activators, models with better predictability are necessary for practical purposes in drug discovery. Grid-weighted holistic invariant molecular (G-WHIM) and comparative molecular moment analysis (G-CoMMA) type 3D descriptors that contain information about the solvation free energy of target molecules were developed. With these descriptors, prediction models built using decision tree (DT)-, support vector machine (SVM)-, and Kohonen neural network (KNN)-based models exhibited better predictability than previously proposed models. Solvation free energy density-weighted G-WHIM and G-CoMMA descriptors reveal new insights into PXR ligand classification, and incorporation with machine learning methods (DT, SVM, KNN) exhibits promising results, especially SVM and KNN. SVM- and KNN-based models exhibit accuracy around 0.90, and DT-based models exhibit accuracy around 0.8 for both the training and test sets.
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Affiliation(s)
- S L Ma
- Department of Biotechnology, Yonsei University, Seoul, Korea
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Predicting Activation of the Promiscuous Human Pregnane X Receptor by Pharmacophore Ensemble/Support Vector Machine Approach. Chem Res Toxicol 2011; 24:1765-78. [DOI: 10.1021/tx200310j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Serra R, Al-Saidi AG, Angelov N, Nares S. Suppression of LPS-induced matrix-metalloproteinase responses in macrophages exposed to phenytoin and its metabolite, 5-(p-hydroxyphenyl-), 5-phenylhydantoin. JOURNAL OF INFLAMMATION-LONDON 2010; 7:48. [PMID: 20843335 PMCID: PMC2949711 DOI: 10.1186/1476-9255-7-48] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 09/15/2010] [Indexed: 11/10/2022]
Abstract
BACKGROUND Phenytoin (PHT) has been reported to induce gingival (gum) overgrowth (GO) in approximately 50% of patients taking this medication. While most studies have focused on the effects of PHT on the fibroblast in the pathophysiology underlying GO, few studies have investigated the potential regulatory role of macrophages in extracellular matrix (ECM) turnover and secretion of proinflammatory mediators. The aim of this study was to evaluate the effects of PHT and its metabolite, 5-(p-hydroxyphenyl-), 5-phenylhydantoin (HPPH) on LPS-elicited MMP, TIMP, TNF-α and IL-6 levels in macrophages. METHODS Human primary monocyte-derived macrophages (n = 6 independent donors) were pretreated with 15-50 μg/mL PHT-Na+ or 15-50 μg/mL HPPH for 1 hour. Cells were then challenged with 100 ng/ml purified LPS from the periodontal pathogen, Aggregatibacter actinomycetemcomitans. Supernatants were collected after 24 hours and levels of MMP-1, MMP-2, MMP-3, MMP-9, MMP-12, TIMP-1, TIMP-2, TIMP-3, TIMP-4, TNF-α and IL-6 determined by multiplex analysis or enzyme-linked immunoadsorbent assay. RESULTS A dose-dependent inhibition of MMP-1, MMP-3, MMP-9, TIMP-1 but not MMP-2 was noted in culture supernatants pretreated with PHT or HPPH prior to LPS challenge. MMP-12, TIMP-2, TIMP-3 and TIMP-2 were not detected in culture supernatants. High concentrations of PHT but not HPPH, blunted LPS-induced TNF-α production although neither significantly affected IL-6 levels. CONCLUSION The ability of macrophages to mediate turnover of ECM via the production of metalloproteinases is compromised not only by PHT, but its metabolite, HPPH in a dose-dependent fashion. Further, the preferential dysregulation of macrophage-derived TNF-α but not IL-6 in response to bacterial challenge may provide an inflammatory environment facilitating collagen accumulation without the counteracting production of MMPs.
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Affiliation(s)
- Ryan Serra
- Department of Periodontology, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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Luke NS, DeVito MJ, Shah I, El-Masri HA. Development of a quantitative model of pregnane X receptor (PXR) mediated xenobiotic metabolizing enzyme induction. Bull Math Biol 2010; 72:1799-819. [PMID: 20151218 DOI: 10.1007/s11538-010-9508-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 01/19/2010] [Indexed: 11/25/2022]
Abstract
The pregnane X receptor plays an integral role in the regulation of hepatic metabolism. It has been shown to regulate CYP3A4, which is the most abundant cytochrome P450 in the human liver. With its large and flexible ligand-binding domain, PXR can be activated by an enormous range of relatively small, hydrophobic, exogenous compounds. Upon activation, PXR partners with the retinoid X receptor (RXR) to form a heterodimer. The newly formed heterodimer binds to an appropriate DNA response element, causing increased transcription. This leads to an induction in the level of CYP3A4. These mechanistic steps are included into a biologically-based mathematical model. The quantitative model predicts fold level inductions of CYP3A4 mRNA and protein in response to PXR activation. Model parameter values have been taken from literature when appropriate. Unknown parameter values are estimated by optimizing the model results to published in vivo and in vitro data sets. A sensitivity analysis is performed to evaluate the model structure and identify future data needs which would be critical to revising the model.
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Affiliation(s)
- Nicholas S Luke
- Department of Mathematics, North Carolina Agricultural and Technical State University, Greensboro, NC 27411, USA.
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Zimmermann K, Wittman MD, Saulnier MG, Velaparthi U, Sang X, Frennesson DB, Struzynski C, Seitz SP, He L, Carboni JM, Li A, Greer AF, Gottardis M, Attar RM, Yang Z, Balimane P, Discenza LN, Lee FY, Sinz M, Kim S, Vyas D. SAR of PXR transactivation in benzimidazole-based IGF-1R kinase inhibitors. Bioorg Med Chem Lett 2010; 20:1744-8. [PMID: 20153189 DOI: 10.1016/j.bmcl.2010.01.087] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 01/04/2010] [Accepted: 01/06/2010] [Indexed: 12/19/2022]
Abstract
The SAR of PXR transactivation by 3-(benzimidazol-2-yl)-pyridine-2-one based ATP competitive inhibitors of Insulin-like Growth Factor 1 Receptor kinase (IGF-1R) is discussed. Compounds without PXR transactivation, with in vivo antitumor activity, reduced protein binding and improved oral exposure are presented.
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Affiliation(s)
- Kurt Zimmermann
- Oncology Chemistry, Bristol-Myers Squibb Co., 5 Research Parkway, Wallingford, CT 06492, USA.
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Argikar UA, Senekeo-Effenberger K, Larson EE, Tukey RH, Remmel RP. Studies on induction of lamotrigine metabolism in transgenic UGT1 mice. Xenobiotica 2009; 39:826-35. [PMID: 19845433 DOI: 10.3109/00498250903188985] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A transgenic 'knock-in' mouse model expressing a human UGT1 locus (Tg-UGT1) was recently developed and validated. Although these animals express mouse UGT1A proteins, UGT1A4 is a pseudo-gene in mice. Therefore, Tg-UGT1 mice serve as a 'humanized' UGT1A4 animal model. Lamotrigine (LTG) is primarily metabolized to its N-glucuronide (LTGG) by hUGT1A4. This investigation aimed at examining the impact of pregnane X receptor (PXR), constitutive androstane receptor (CAR) and peroxisome proliferator-activated receptor (PPAR) activators on LTG glucuronidation in vivo and in vitro. Tg-UGT1 mice were administered the inducers phenobarbital (CAR), pregnenolone-16alpha-carbonitrile (PXR), WY-14643 (PPAR-alpha), ciglitazone (PPAR-gamma), or L-165041 (PPAR-beta), once daily for 3 or 4 days. Thereafter, LTG was administered orally and blood samples were collected over 24 h. LTG was measured in blood and formation of LTGG was measured in pooled microsomes made from the livers of treated animals. A three-fold increase in in vivo LTG clearance was seen after phenobarbital administration. In microsomes prepared from phenobarbital-treated Tg-UGT1 animals, 13-fold higher CL(int) (Vmax/K(m)) value was observed as compared with the untreated transgenic mice. A trend toward induction of catalytic activity in vitro and in vivo was also observed following pregnenolone-16alpha-carbonitrile and WY-14643 treatment. This study demonstrates the successful application of Tg-UGT1 mice as a novel tool to study the impact of induction and regulation on metabolism of UGT1A4 substrates.
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Affiliation(s)
- U A Argikar
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
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Krämer S, Testa B. The Biochemistry of Drug Metabolism - An Introduction. Chem Biodivers 2009; 6:1477-660, table of contents. [DOI: 10.1002/cbdv.200900233] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Masson D, Qatanani M, Sberna AL, Xiao R, Pais de Barros JP, Grober J, Deckert V, Athias A, Gambert P, Lagrost L, Moore DD, Assem M. Activation of the constitutive androstane receptor decreases HDL in wild-type and human apoA-I transgenic mice. J Lipid Res 2008; 49:1682-91. [DOI: 10.1194/jlr.m700374-jlr200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Furihata T, Satoh T, Yamamoto N, Kobayashi K, Chiba K. Hepatocyte nuclear factor 1 alpha is a factor responsible for the interindividual variation of OATP1B1 mRNA levels in adult Japanese livers. Pharm Res 2007; 24:2327-32. [PMID: 17932728 DOI: 10.1007/s11095-007-9458-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Accepted: 09/10/2007] [Indexed: 11/29/2022]
Abstract
PURPOSE The aim of the present study was to clarify the factors responsible for interindividual variability of organic anion transporting polypeptide (OATP, gene symbol SLCO) 1B1 mRNA expression level in the human liver. MATERIALS AND METHODS OATP1B1 mRNA expression levels were determined by real-time PCR in 31 human liver samples. The results were analyzed in relation to a single nucleotide polymorphism (-11187G>A) located in the promoter region and levels of hepatocyte nuclear factor (HNF) 1alpha mRNA. RESULTS There was a 4.9-fold interindividual variability of OATP1B1 mRNA expression level in the livers analyzed, which was not associated with -11187G>A polymorphism. Accordingly, the -11187G>A polymorphism did not alter the SLCO1B1 gene promoter activity in luciferase assays. On the other hand, OATP1B1 mRNA levels showed a significant correlation with HNF1alpha mRNA levels (r=0.83, P<0.0001). This correlation was consistent with the results of luciferase assays and chromatin immunoprecipitation assays showing functional interaction between HNF1alpha and SLCO1B1 gene promoter. CONCLUSIONS Our results suggest that HNF1alpha is an essential regulator of OATP1B1 mRNA expression and thus the level of HNF1alpha expression is one of the major determinants of interindividual variability in OATP1B1 mRNA expression.
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Affiliation(s)
- Tomomi Furihata
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8675, Japan.
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Abstract
The pregnane X receptor (PXR; NR1I2) is a nuclear hormone receptor (NR) that transcriptionally regulates genes encoding transporters and drug-metabolising enzymes in the liver and intestine. PXR activation leads to enhanced metabolism and elimination of xenobiotics and endogenous compounds such as hormones and bile salts. Relative to other vertebrate NRs, PXR has the broadest specificity for ligand activators by virtue of a large, flexible ligand-binding cavity. In addition, PXR has the most extensive sequence diversity across vertebrate species in the ligand-binding domain of any NR, with significant pharmacological differences between human and rodent PXRs, and especially marked divergence between mammalian and nonmammalian PXRs. The unusual properties of PXR complicate the use of in silico and animal models to predict in vivo human PXR pharmacology. Research into the evolutionary history of the PXR gene has also provided insight into the function of PXR in humans and other animals.
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Affiliation(s)
- Manisha Iyer
- University of Pittsburgh, Department of Pathology, Scaife Hall S-730, 3550 Terrace Street, Pittsburgh, PA 15261 USA
| | - Erica J. Reschly
- University of Pittsburgh, Department of Pathology, Scaife Hall S-730, 3550 Terrace Street, Pittsburgh, PA 15261 USA
| | - Matthew D. Krasowski
- University of Pittsburgh, Department of Pathology, Scaife Hall S-730, 3550 Terrace Street, Pittsburgh, PA 15261 USA
- Author for correspondence, Tel: 412-647-6517; Fax: 412-647-5934; E-mail:
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Lee MD, Ayanoglu E, Gong L. Drug-induced changes in P450 enzyme expression at the gene expression level: a new dimension to the analysis of drug-drug interactions. Xenobiotica 2007; 36:1013-80. [PMID: 17118918 DOI: 10.1080/00498250600861785] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Drug-drug interactions (DDIs) caused by direct chemical inhibition of key drug-metabolizing cytochrome P450 enzymes by a co-administered drug have been well documented and well understood. However, many other well-documented DDIs cannot be so readily explained. Recent investigations into drug and other xenobiotic-mediated expression changes of P450 genes have broadened our understanding of drug metabolism and DDI. In order to gain additional information on DDI, we have integrated existing information on drugs that are substrates, inhibitors, or inducers of important drug-metabolizing P450s with new data on drug-mediated expression changes of the same set of cytochrome P450s from a large-scale microarray gene expression database of drug-treated rat tissues. Existing information on substrates and inhibitors has been updated and reorganized into drug-cytochrome P450 matrices in order to facilitate comparative analysis of new information on inducers and suppressors. When examined at the gene expression level, a total of 119 currently marketed drugs from 265 examined were found to be cytochrome P450 inducers, and 83 were found to be suppressors. The value of this new information is illustrated with a more detailed examination of the DDI between PPARalpha agonists and HMG-CoA reductase inhibitors. This paper proposes that the well-documented, but poorly understood, increase in incidence of rhabdomyolysis when a PPARalpha agonist is co-administered with a HMG-CoA reductase inhibitor is at least in part the result of PPARalpha-induced general suppression of drug metabolism enzymes in liver. The authors believe this type of information will provide insights to other poorly understood DDI questions and stimulate further laboratory and clinical investigations on xenobiotic-mediated induction and suppression of drug metabolism.
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Affiliation(s)
- M D Lee
- Iconix Biosciences, Mountain View, CA 94043, USA.
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Stanley LA, Horsburgh BC, Ross J, Scheer N, Wolf CR. PXR and CAR: nuclear receptors which play a pivotal role in drug disposition and chemical toxicity. Drug Metab Rev 2006; 38:515-97. [PMID: 16877263 DOI: 10.1080/03602530600786232] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Xenobiotic metabolism and detoxification is regulated by receptors (e.g., PXR, CAR) whose characterization has contributed significantly to our understanding of drug responses in humans. Technologies facilitating the screening of compounds for receptor interactions provide valuable tools applicable in drug development. Most use in vitro systems or mice humanized for receptors in vivo. In vitro assays are limited by the reporter systems and cell lines chosen and are uninformative about effects in vivo. Humanized mouse models provide novel, exciting ways of understanding the functions of these genes. This article evaluates these technologies and current knowledge on PXR/CAR-mediated regulation of gene expression.
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Affiliation(s)
- Lesley A Stanley
- Consultant in Investigative Toxicology, St. Andrews, Fife, United Kingdom
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Kawashima S, Kobayashi K, Takama K, Higuchi T, Furihata T, Hosokawa M, Chiba K. INVOLVEMENT OF HEPATOCYTE NUCLEAR FACTOR 4α IN THE DIFFERENT EXPRESSION LEVEL BETWEEN CYP2C9 AND CYP2C19 IN THE HUMAN LIVER. Drug Metab Dispos 2006; 34:1012-8. [PMID: 16540586 DOI: 10.1124/dmd.106.009365] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
CYP2C9 and CYP2C19 are clinically important drug-metabolizing enzymes. The expression level of CYP2C9 is much higher than that of CYP2C19, although the factor(s) responsible for the difference between the expression levels of these genes is still unclear. It has been reported that hepatocyte nuclear factor 4alpha (HNF4alpha) plays an important role in regulation of the expression of liver-enriched genes, including P450 genes. Thus, we hypothesized that HNF4alpha contributes to the difference between the expression levels of these genes. Two direct repeat 1 (DR1) elements were located in both the CYP2C9 and CYP2C19 promoters. The upstream and downstream elements in these promoters had the same sequences, and HNF4alpha could bind to both elements in vitro. The transactivation levels of constructs containing two DR1 elements of the CYP2C9 promoter were increased by HNF4alpha, whereas those of the CYP2C19 promoter were not increased. The introduction of mutations into either the upstream or downstream element in the CYP2C9 gene abolished the responsiveness to HNF4alpha. We also examined whether HNF4alpha could bind to the promoter regions of the CYP2C9 and the CYP2C19 genes in vivo. The results of chromatin immunoprecipitation assays showed that HNF4alpha could bind to the promoter region of the CYP2C9 gene but not to that of the CYP2C19 promoter in the human liver. Taken together, our results suggest that HNF4alpha is a factor responsible for the difference between the expression levels of CYP2C9 and CYP2C19 in the human liver.
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Affiliation(s)
- Sachiyo Kawashima
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chiba 260-8675, Japan
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Choudhuri S, Valerio LG. Usefulness of studies on the molecular mechanism of action of herbals/botanicals: The case of St. John's wort. J Biochem Mol Toxicol 2005; 19:1-11. [PMID: 15736155 DOI: 10.1002/jbt.20057] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The use of herbals/botanicals has been gaining wide popularity in recent years in the United States as well as in other parts of the world. The mechanism of action of most of these herbals/botanicals has not been subjected to thorough scientific investigations. St. John's wort (Hypericum perforatum) represents a useful case study in this sense. Traditionally, it is used as a natural treatment for depression; however, in recent years its molecular mechanism of action has been elucidated by a number of laboratories across the world. Such studies have helped understand potential interactions of St. John's wort with drugs and other xenobiotics. St. John's wort activates a nuclear receptor called pregnane X receptor (PXR). PXR is a ligand-activated transcription factor that induces a number of xenobiotic-metabolizing enzymes and transporters including cytochrome P4503A4 (CYP3A4) in humans. Because CYP3A4 alone metabolizes about 60% of all clinically relevant drugs, induction of CYP3A4 may result in the rapid elimination of these drugs and a consequent reduction in drug efficacy. Ironically, such enzyme-inducing effects may not produce any immediate adverse symptomatology in the person taking St. John's wort. Therefore, the case of St. John's wort should serve as a good example of the usefulness and importance of studies on the mechanism of action of the herbals/botanicals, particularly those with widespread use. Scientists, physicians, and other health professionals can make use of the knowledge from such studies as an additional risk management tool.
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Affiliation(s)
- Supratim Choudhuri
- Division of Biotechnology and GRAS Notice Review, Office of Food Additive Safety, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, MD 20740, USA.
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Kobayashi K, Yamanaka Y, Iwazaki N, Nakajo I, Hosokawa M, Negishi M, Chiba K. Identification of HMG-CoA reductase inhibitors as activators for human, mouse and rat constitutive androstane receptor. Drug Metab Dispos 2005; 33:924-9. [PMID: 15802384 DOI: 10.1124/dmd.104.002741] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Constitutive active (or androstane) receptor (CAR, NR1I3), a member of the nuclear receptor family, is a major regulator for induction of cytochrome P450 2B (CYP2B) genes by phenobarbital. Phenobarbital-like inducer, 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene is a potent mouse CAR ligand that has been used to study CAR target genes in mice but does not activate human CAR (hCAR) or rat CAR (rCAR). Although 6-(4-chlorophenyl) imidazo[2,1-b][1,3]thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime (CITCO) was reported to be an hCAR agonistic ligand, activation of hCAR by CITCO in cell-based reporter assay was weak. Therefore, we performed a screening of 50 drugs and chemicals using cell-based reporter assays to identify activators of hCAR. Among them, HMG-CoA reductase inhibitors (cerivastatin, simvastatin, fluvastatin, and atorvastatin) enhanced the hCAR-mediated transcriptional activation of phenobarbital-responsive enhancer module reporter gene by up to 3-fold. Similar activation by HMG-CoA reductase inhibitors was also observed with mouse and rat CARs. On the other hand, pravastatin did not activate hCAR at the concentrations tested (up to 30 microM). The extent of activation by the HMG-CoA reductase inhibitors was stronger than that by CITCO. Cerivastatin, simvastatin, fluvastatin, and atorvastatin induced CYP2B6 mRNA in stable hCAR-expressed FLC7 cells but not in original FLC7 cells. Therefore, we concluded that CAR mediates the effects of HMG-CoA reductase inhibitors on the induction of CYP2B genes, although HMG-CoA reductase inhibitors also activate pregnane X receptor. HMG-CoA reductase inhibitors such as cerivastatin would be useful to study for elucidating molecular and cellular mechanisms of hCAR.
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Affiliation(s)
- Kaoru Kobayashi
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chuo-ku, Chiba 260-8675, Japan.
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