1
|
Poudel S, Huber AD, Chen T. Regulation of Nuclear Receptors PXR and CAR by Small Molecules and Signal Crosstalk: Roles in Drug Metabolism and Beyond. Drug Metab Dispos 2023; 51:228-236. [PMID: 36116789 PMCID: PMC9900866 DOI: 10.1124/dmd.122.000858] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/16/2022] [Accepted: 08/29/2022] [Indexed: 01/31/2023] Open
Abstract
Pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are ligand-activated transcription factors that regulate the expression of drug metabolizing enzymes and drug transporters. Since their discoveries, they have been studied as important factors for regulating processes related to drug efficacy, drug toxicity, and drug-drug interactions. However, their vast ligand-binding profiles extend into additional spaces, such as endogenously produced chemicals, microbiome metabolites, dietary compounds, and environmental pollutants. Therefore, PXR and CAR can respond to an enormous abundance of stimuli, resulting in significant shifts in metabolic programs and physiologic homeostasis. Naturally, PXR and CAR have been implicated in various diseases related to homeostatic perturbations, such as inflammatory bowel disorders, diabetes, and certain cancers. Recent findings have injected the field with new signaling mechanisms and tools to dissect the complex PXR and CAR biology and have strengthened the potential for future PXR and CAR modulators in the clinic. Here, we describe the historical and ongoing importance of PXR and CAR in drug metabolism pathways and how this history has evolved into new mechanisms that regulate and are regulated by these xenobiotic receptors, with a specific focus on small molecule ligands. To effectively convey the impact of newly emerging research, we have arranged five diverse and representative key recent advances, four specific challenges, and four perspectives on future directions. SIGNIFICANCE STATEMENT: PXR and CAR are key transcription factors that regulate homeostatic detoxification of the liver and intestines. Diverse chemicals bind to these nuclear receptors, triggering their transcriptional tuning of the cellular metabolic response. This minireview revisits the importance of PXR and CAR in pharmaceutical drug responses and highlights recent results with implications beyond drug metabolism.
Collapse
Affiliation(s)
- Shyaron Poudel
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Andrew D Huber
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee
| |
Collapse
|
2
|
Hrubec TC, Seguin RP, Xu L, Cortopassi GA, Datta S, Hanlon AL, Lozano AJ, McDonald VA, Healy CA, Anderson TC, Musse NA, Williams RT. Altered toxicological endpoints in humans from common quaternary ammonium compound disinfectant exposure. Toxicol Rep 2021; 8:646-656. [PMID: 33868951 PMCID: PMC8041661 DOI: 10.1016/j.toxrep.2021.03.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/04/2021] [Accepted: 03/06/2021] [Indexed: 12/18/2022] Open
Abstract
Humans are frequently exposed to Quaternary Ammonium Compounds (QACs). QACs are ubiquitously used in medical settings, restaurants, and homes as cleaners and disinfectants. Despite their prevalence, nothing is known about the health effects associated with chronic low-level exposure. Chronic QAC toxicity, only recently identified in mice, resulted in developmental, reproductive, and immune dysfunction. Cell based studies indicate increased inflammation, decreased mitochondrial function, and disruption of cholesterol synthesis. If these findings translate to human toxicity, multiple physiological processes could be affected. This study tested whether QAC concentrations could be detected in the blood of 43 human volunteers, and whether QAC concentrations influenced markers of inflammation, mitochondrial function, and cholesterol synthesis. QAC concentrations were detected in 80 % of study participants. Blood QACs were associated with increase in inflammatory cytokines, decreased mitochondrial function, and disruption of cholesterol homeostasis in a dose dependent manner. This is the first study to measure QACs in human blood, and also the first to demonstrate statistically significant relationships between blood QAC and meaningful health related biomarkers. Additionally, the results are timely in light of the increased QAC disinfectant exposure occurring due to the SARS-CoV-2 pandemic. MAIN FINDINGS This study found that 80 % of study participants contained QACs in their blood; and that markers of inflammation, mitochondrial function, and sterol homeostasis varied with blood QAC concentration.
Collapse
Key Words
- 7-DHC, 7-Dehydrocholesterol
- 7-DHD, 7-Dehydrodesmosterol
- 8-DHC, 8-Dehydrocholesterol
- ADBAC, alkyldimethylbenzyl ammonium chloride
- ANOVA, analysis of variance
- BAC, benzalkonium chloride
- CRP, C-reactive protein
- DDAC, didecyldimethyl ammonium chloride
- Environmental toxicology
- FCCP, trifluoromethoxy carbonylcyanide phenylhydrazone
- IL-10, interleukin 10
- IL-12, interleukin 12
- IL-6, interleukin 6
- IRB, Institutional Review Board
- Inflammation
- LC, liquid chromatography
- LOD, level of detection
- LOQ, level of quantification
- LPS, lipopolysaccharide
- Lipid metabolism
- Mitochondrial function
- NF-κB, nuclear factor kappa beta
- NOEL, no effect level
- OCR, oxygen consumption rate
- OEL, occupational exposure limit
- QAC, quaternary ammonium compounds
- Quaternary ammonium compounds
- TNFα, tumor necrosis factor alpha
Collapse
Affiliation(s)
- Terry C. Hrubec
- Department of Biomedical Science, E. Via College of Osteopathic Medicine – Virginia, Blacksburg, VA, 24060, USA
- Department of Biomedical Science and Pathobiology, VA-MD College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Ryan P. Seguin
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA, 98195, USA
| | - Libin Xu
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA, 98195, USA
| | - Gino A. Cortopassi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California – Davis, Davis, CA, 95618, USA
| | - Sandipan Datta
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California – Davis, Davis, CA, 95618, USA
| | - Alexandra L. Hanlon
- Center for Biostatistics and Health Data Science, Department of Statistics, College of Science, Virginia Tech, Riverside Circle, Roanoke, VA, 24016, USA
| | - Alicia J. Lozano
- Center for Biostatistics and Health Data Science, Department of Statistics, College of Science, Virginia Tech, Riverside Circle, Roanoke, VA, 24016, USA
| | - Valerie A. McDonald
- Department of Biomedical Science, E. Via College of Osteopathic Medicine – Virginia, Blacksburg, VA, 24060, USA
| | - Claire A. Healy
- Department of Biomedical Science, E. Via College of Osteopathic Medicine – Virginia, Blacksburg, VA, 24060, USA
| | - Tyler C. Anderson
- Department of Biomedical Science, E. Via College of Osteopathic Medicine – Virginia, Blacksburg, VA, 24060, USA
| | - Najaha A. Musse
- Department of Biomedical Science, E. Via College of Osteopathic Medicine – Virginia, Blacksburg, VA, 24060, USA
| | - Richard T. Williams
- Department of Biomedical Science, E. Via College of Osteopathic Medicine – Virginia, Blacksburg, VA, 24060, USA
| |
Collapse
|
3
|
He Y, Wei Z, Ci X, Xie Y, Yi X, Zeng Y, Li Y, Liu C. Effects of liquorice on pharmacokinetics of aconitine in rats. Xenobiotica 2019; 49:1485-1493. [DOI: 10.1080/00498254.2019.1579007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Yufei He
- Shenyang Pharmaceutical University, Shenyang, PR China
| | - Zihong Wei
- State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics, Tianjin Institute of Pharmaceutical Research, Tianjin, PR China
- Tianjin Institute of Pharmaceutical Research, New Drug Assessment Co. Ltd, Tianjin, PR China
| | - Xiaoyan Ci
- State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics, Tianjin Institute of Pharmaceutical Research, Tianjin, PR China
- Tianjin Institute of Pharmaceutical Research, New Drug Assessment Co. Ltd, Tianjin, PR China
| | - Ying Xie
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, PR China
| | - Xiulin Yi
- State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics, Tianjin Institute of Pharmaceutical Research, Tianjin, PR China
- Tianjin Institute of Pharmaceutical Research, New Drug Assessment Co. Ltd, Tianjin, PR China
| | - Yong Zeng
- State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics, Tianjin Institute of Pharmaceutical Research, Tianjin, PR China
- Tianjin Institute of Pharmaceutical Research, New Drug Assessment Co. Ltd, Tianjin, PR China
| | - Yazhuo Li
- State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics, Tianjin Institute of Pharmaceutical Research, Tianjin, PR China
- Tianjin Institute of Pharmaceutical Research, New Drug Assessment Co. Ltd, Tianjin, PR China
| | - Changxiao Liu
- Shenyang Pharmaceutical University, Shenyang, PR China
- State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics, Tianjin Institute of Pharmaceutical Research, Tianjin, PR China
| |
Collapse
|
4
|
Jeon YJ, Kim MH. Effect of levetiracetam on rocuronium duration in patients undergoing cerebrovascular surgery. Anesth Pain Med (Seoul) 2018. [DOI: 10.17085/apm.2018.13.4.409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Young-Jae Jeon
- Department of Anesthesiology and Pain Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Mi-hyun Kim
- Department of Anesthesiology and Pain Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| |
Collapse
|
5
|
Genovese I, Ilari A, Assaraf YG, Fazi F, Colotti G. Not only P-glycoprotein: Amplification of the ABCB1- containing chromosome region 7q21 confers multidrug resistance upon cancer cells by coordinated overexpression of an assortment of resistance-related proteins. Drug Resist Updat 2017; 32:23-46. [DOI: 10.1016/j.drup.2017.10.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/01/2017] [Accepted: 10/11/2017] [Indexed: 02/07/2023]
|
6
|
Mikkaichi T, Yoshigae Y, Masumoto H, Imaoka T, Rozehnal V, Fischer T, Okudaira N, Izumi T. Edoxaban transport via P-glycoprotein is a key factor for the drug's disposition. Drug Metab Dispos 2014; 42:520-8. [PMID: 24459178 DOI: 10.1124/dmd.113.054866] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Edoxaban (the free base of DU-176b), an oral direct factor Xa inhibitor, is mainly excreted unchanged into urine and feces. Because active membrane transport processes such as active renal secretion, biliary excretion, and/or intestinal secretion, and the incomplete absorption of edoxaban after oral administration have been observed, the involvement of drug transporters in the disposition of edoxaban was investigated. Using a bidirectional transport assay in human colon adenocarcinoma Caco-2 cell monolayers, we observed the vectorial transport of [(14)C]edoxaban, which was completely inhibited by verapamil, a strong P-glycoprotein (P-gp) inhibitor. In an in vivo study, an increased distribution of edoxaban to the brain was observed in Mdr1a/1b knockout mice when compared with wild-type mice, indicating that edoxaban is a substrate for P-gp. However, there have been no observations of significant transport of edoxaban by renal or hepatic uptake transporters, organic anion transporter (OAT)1, OAT3, organic cation transporter (OCT)2, or organic anion transporting polypeptide (OATP)1B1. Edoxaban exhibited no remarkable inhibition of OAT1, OAT3, OCT1, OCT2, OATP1B1, OATP1B3, or P-gp up to 30 μM; therefore, the risk of clinical drug-drug interactions due to any edoxaban-related transporter inhibition seems to be negligible. Our results demonstrate that edoxaban is a substrate of P-gp but not of other major uptake transporters tested. Because metabolism is a minor contributor to the total clearance of edoxaban and strong P-gp inhibitors clearly impact edoxaban transport, the P-gp transport system is a key factor for edoxaban's disposition.
Collapse
Affiliation(s)
- Tsuyoshi Mikkaichi
- Drug Metabolism & Pharmacokinetics Research Laboratories, Daiichi Sankyo Co., Ltd., Tokyo, Japan (T.M., Y.Y., T.Im., N.O., T.Iz.); Daiichi Sankyo Pharma Development, Edison, New Jersey, (H.M.); and Tissue and Cell Research Center Munich, Daiichi Sankyo Europe GmbH, Munich, Germany (V.R., T.F.)
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Huang L, Perrault C, Coelho-Martins J, Hu C, Dulong C, Varna M, Liu J, Jin J, Soria C, Cazin L, Janin A, Li H, Varin R, Lu H. Induction of acquired drug resistance in endothelial cells and its involvement in anticancer therapy. J Hematol Oncol 2013; 6:49. [PMID: 23837843 PMCID: PMC3717049 DOI: 10.1186/1756-8722-6-49] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 05/31/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Multidrug resistance (MDR) is one of the major problems in the treatment of cancer. Overcoming it is therefore expected to improve clinical outcomes for cancer patients. MDR is usually characterized by overexpression of ABC (ATP-binding cassette) protein transporters such as P-gp, MRP1, and ABCG2. Though the importance of ABC transporters for cancer cells is recognized, few studies have looked at its implications for the endothelial cells that are essential to tumor angiogenesis. This study investigated the expression and functions of these ABC transporters in endothelial cells in vitro and their potential contribution to cancer growth in mice. METHODS Human micro vessel endothelial cells (HMEC-1) and human umbilical vein endothelial cells (HUVEC) were exposed to increasing doses of Doxorubicin (Dox) to induce ABC gene expression. Cell viability was then quantified by (3)H-thymidine and MTS assay. Flow cytometry, qPCR, and western blot were used to detect mRNA and the protein expression of P-gp, MRP1, and ABCG2. The intracellular accumulation of Rhodamine 123 (Rho) was used to evaluate drug efflux function and the inhibitors for P-gp, ABCG2, and MRP1 were used to verify their respective roles in vitro. In an attempt to evaluate drug resistance in endothelial cells in vivo, athymic mice were treated with Dox for 15 days before a MDA-MB-435 tumor graft to observe subsequent changes in the inhibition curves of tumor growth in response to Dox treatment. Furthermore, endothelial cells from multiple sites in these mice were also isolated to estimate their P-gp expression by flow cytometry. RESULTS Drug resistance in HMEC-1 and HUVEC was successfully induced by the addition of Dox to the culture media. Two stabilized subcell lines of HMEC1 (HMECd1 and HMECd2) showed 15- and 24-fold increases in resistance. Tests also showed that these induced endothelial cells were cross-resistant to the structurally unrelated drugs Daunorubicin, Vinblastine, and Etoposide. P-gp protein levels increased four and six fold in HMECd1 and HMECd2 as revealed by western blot. The qPCR demonstrated 3.4- and 7.2-fold increases in P-gp, and a slight increase in ABCG2, gene expression. The Rho accumulation within these cells was inversely correlated with the expression levels of P-gp. The inhibitors of P-gp, but not of ABCG2 or MRP1, were able to block the induced endothelial cell resistance to Dox. Furthermore, we also showed that injecting Dox into healthy mice induced an increase in P-gp expression in endothelial cells. Using these pretreated mice in a tumor growth experiment, we observed a dramatic diminution in the therapeutic efficiency of Dox treatment, suggesting implications for drug resistance in mice endothelial cells supporting tumor growth. CONCLUSIONS ABC transporter expression can be induced in endothelial cells in vitro. This study also indicates that P-gp plays an important role in the acquisition of resistance to Dox in endothelial cells and that this reduces the efficiency of chemotherapy.
Collapse
|
8
|
Xia B, Heimbach T, Gollen R, Nanavati C, He H. A simplified PBPK modeling approach for prediction of pharmacokinetics of four primarily renally excreted and CYP3A metabolized compounds during pregnancy. AAPS JOURNAL 2013; 15:1012-24. [PMID: 23835676 DOI: 10.1208/s12248-013-9505-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 06/12/2013] [Indexed: 02/02/2023]
Abstract
During pregnancy, a drug's pharmacokinetics may be altered and hence anticipation of potential systemic exposure changes is highly desirable. Physiologically based pharmacokinetics (PBPK) models have recently been used to influence clinical trial design or to facilitate regulatory interactions. Ideally, whole-body PBPK models can be used to predict a drug's systemic exposure in pregnant women based on major physiological changes which can impact drug clearance (i.e., in the kidney and liver) and distribution (i.e., adipose and fetoplacental unit). We described a simple and readily implementable multitissue/organ whole-body PBPK model with key pregnancy-related physiological parameters to characterize the PK of reference drugs (metformin, digoxin, midazolam, and emtricitabine) in pregnant women compared with the PK in nonpregnant or postpartum (PP) women. Physiological data related to changes in maternal body weight, tissue volume, cardiac output, renal function, blood flows, and cytochrome P450 activity were collected from the literature and incorporated into the structural PBPK model that describes HV or PP women PK data. Subsequently, the changes in exposure (area under the curve (AUC) and maximum concentration (C max)) in pregnant women were simulated. Model-simulated PK profiles were overall in agreement with observed data. The prediction fold error for C max and AUC ratio (pregnant vs. nonpregnant) was less than 1.3-fold, indicating that the pregnant PBPK model is useful. The utilization of this simplified model in drug development may aid in designing clinical studies to identify potential exposure changes in pregnant women a priori for compounds which are mainly eliminated renally or metabolized by CYP3A4.
Collapse
Affiliation(s)
- Binfeng Xia
- Novartis Institutes for Biomedical Research, DMPK-Translational Sciences, One Health Plaza 436/3253, East Hanover, New Jersey, 07470, USA
| | | | | | | | | |
Collapse
|
9
|
Song IS, Choi MK, Shim WS, Shim CK. Transport of organic cationic drugs: effect of ion-pair formation with bile salts on the biliary excretion and pharmacokinetics. Pharmacol Ther 2013; 138:142-54. [PMID: 23353097 DOI: 10.1016/j.pharmthera.2013.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 01/10/2013] [Indexed: 01/11/2023]
Abstract
More than 40% of clinically used drugs are organic cations (OCs), which are positively charged at a physiologic pH, and recent reports have established that these drugs are substrates of membrane transporters. The transport of OCs via membrane transporters may play important roles in gastrointestinal absorption, distribution to target sites, and biliary and/or renal elimination of various OC drugs. Almost 40 years ago, a molecular weight (Mw) threshold of 200 was reported to exist in rats for monoquaternary ammonium (mono QA) compounds to be substantially (e.g., >10% of iv dose) excreted to bile. It is well known that some OCs interact with appropriate endogenous organic anions in the body (e.g., bile salts) to form lipophilic ion-pair complexes. The ion-pair formation may influence the affinity or binding of OCs to membrane transporters that are relevant to biliary excretion. In that sense, the association of the ion-pair formation with the existence of the Mw threshold appears to be worthy of examination. It assumes the ion-pair formation of high Mw mono QA compounds (i.e., >200) in the presence of bile salts in the liver, followed by accelerated transport of the ion-pair complexes via relevant bile canalicular transporter(s). In this article, therefore, the transport of OC drugs will be reviewed with a special focus on the ion-pair formation hypothesis. Such information will deepen the understanding of the pharmacokinetics of OC drugs as well as the physiological roles of endogenous bile salts in the detoxification or phase II metabolism of high Mw QA drugs.
Collapse
Affiliation(s)
- I S Song
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea
| | | | | | | |
Collapse
|
10
|
Yoshida K, Maeda K, Sugiyama Y. Hepatic and Intestinal Drug Transporters: Prediction of Pharmacokinetic Effects Caused by Drug-Drug Interactions and Genetic Polymorphisms. Annu Rev Pharmacol Toxicol 2013; 53:581-612. [DOI: 10.1146/annurev-pharmtox-011112-140309] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Kenta Yoshida
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan; ,
| | - Kazuya Maeda
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan; ,
| | - Yuichi Sugiyama
- Sugiyama Laboratory, RIKEN Innovation Center, RIKEN Research Cluster for Innovation, Yokohama 230-0045, Japan;
| |
Collapse
|
11
|
Chen KG, Sikic BI. Molecular pathways: regulation and therapeutic implications of multidrug resistance. Clin Cancer Res 2012; 18:1863-9. [PMID: 22344233 DOI: 10.1158/1078-0432.ccr-11-1590] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Multidrug transporters constitute major mechanisms of MDR in human cancers. The ABCB1 (MDR1) gene encodes a well-characterized transmembrane transporter, termed P-glycoprotein (P-gp), which is expressed in many normal human tissues and cancers. P-gp plays a major role in the distribution and excretion of drugs and is involved in intrinsic and acquired drug resistance of cancers. The regulation of ABCB1 expression is complex and has not been well studied in a clinical setting. In this review, we elucidate molecular signaling and epigenetic interactions that govern ABCB1 expression and the development of MDR in cancer. We focus on acquired expression of ABCB1 that is associated with genomic instability of cancer cells, including mutational events that alter chromatin structures, gene rearrangements, and mutations in tumor suppressor proteins (e.g., mutant p53), which guard the integrity of genome. In addition, epigenetic modifications of the ABCB1 proximal and far upstream promoters by either demethylation of DNA or acetylation of histone H3 play a pivotal role in inducing ABCB1 expression. We describe a molecular network that coordinates genetic and epigenetic events leading to the activation of ABCB1. These mechanistic insights provide additional translational targets and potential strategies to deal with clinical MDR.
Collapse
Affiliation(s)
- Kevin G Chen
- Division of Oncology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305-5151., USA
| | | |
Collapse
|
12
|
Increased Affinity to Canalicular P-gp via Formation of Lipophilic Ion-Pair Complexes with Endogenous Bile Salts is Associated with Mw Threshold in Hepatobiliary Excretion of Quaternary Ammonium Compounds. Pharm Res 2010; 27:823-31. [DOI: 10.1007/s11095-010-0075-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 11/24/2009] [Indexed: 10/19/2022]
|
13
|
Anger G, Magomedova L, Piquette-Miller M. Impact of Acute Streptozotocin-Induced Diabetes on ABC Transporter Expression in Rats. Chem Biodivers 2009; 6:1943-59. [DOI: 10.1002/cbdv.200900053] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
14
|
Disposition and toxicity of trabectedin (ET-743) in wild-type and mdr1 gene (P-gp) knock-out mice. Invest New Drugs 2009; 28:145-55. [PMID: 19238326 DOI: 10.1007/s10637-009-9234-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Accepted: 02/12/2009] [Indexed: 10/21/2022]
Abstract
Trabectedin is a novel anticancer drug active against soft tissue sarcomas. Trabectedin is a substrate for P-glycoprotein (P-gp), which is encoded by mdr1a/1b in rodents. Plasma and tissue distribution, and excretion of [(14)C]-trabectedin were evaluated in wild-type and mdr1a/1b(-/-) mice. In parallel, we investigated the toxicity profile of trabectedin by serial measurements of blood liver enzymes and general pathology. [(14)C]-trabectedin was extensively distributed into tissues, and rapidly converted into a range of unknown metabolic products. The excretion of radioactivity was similar in both genotypes. The plasma clearance of unchanged trabectedin was not reduced when P-gp was absent, but organs under wild type circumstances protected by P-gp showed increased trabectedin concentrations in mdr1a/1b(-/-) mice. Although hepatic trabectedin concentrations were not increased when P-gp was absent, mdr1a/1b(-/-) mice experienced more severe liver toxicity. P-gp plays a role in the in vivo disposition and toxicology of trabectedin.
Collapse
|
15
|
Stanley LA, Horsburgh BC, Ross J, Scheer N, Wolf CR. Drug transporters: Gatekeepers controlling access of xenobiotics to the cellular interior. Drug Metab Rev 2009; 41:27-65. [DOI: 10.1080/03602530802605040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
16
|
Zhang G, Zhang B, Fu X, Tomozawa H, Matsumoto K, Higuchi K, Mori M. Senescence-Accelerated Mouse (SAM) strains have a spontaneous mutation in the Abcb1a gene. Exp Anim 2008; 57:413-7. [PMID: 18633165 DOI: 10.1538/expanim.57.413] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Senescence-Accelerated Mouse (SAM) strains are used as animal models for gerontological research. Here, we report that the SAMR1 strain, which shows a high sensitivity to toxicity of the parasiticide ivermectin, has a spontaneous retroviral insertional mutation in the ATP-binding cassette, sub-family B (MDR/TAP), member 1A (Abcb1a) gene. This mutation is identical to that found in Crl:CF1-Abcb1a mice, which are also highly sensitive to ivermectin due to the mutation. The mutant Abcb1a allele was found in SAMR4, SAMR5, SAMP1, SAMP6, SAMP7, and SAMP9, but not in SAMP3, SAMP8, SAMP10, SAMP11, and other outbred and inbred strains, including 129/SvJ strains. These results impart both caution and promise in the use of SAM strains in studies of biological processes in which P-glycoprotein participates.
Collapse
Affiliation(s)
- Guohong Zhang
- Department of Aging Biology, Institute on Aging and Adaptation, Shinshu University Graduate School of Medicine, Matsumoto, Japan
| | | | | | | | | | | | | |
Collapse
|
17
|
Garner CE, Solon E, Lai CM, Lin J, Luo G, Jones K, Duan J, Decicco CP, Maduskuie T, Mercer SE, Gan LS, Qian M, Prakash S, Shen HS, Lee FW. Role of P-Glycoprotein and the Intestine in the Excretion of DPC 333 [(2R)-2-{(3R)-3-Amino-3-[4-(2-methylquinolin-4-ylmethoxy)phenyl]-2-oxopyrrolidin-1-yl}-N-hydroxy-4-methylpentanamide] in Rodents. Drug Metab Dispos 2008; 36:1102-10. [DOI: 10.1124/dmd.107.017038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
18
|
Peralta G, Blanca Sánchez M, Echevarría S, María Valdizán E, Antonio Armijo J. Glucoproteína P e infección por el virus de la inmunodeficiencia humana. Enferm Infecc Microbiol Clin 2008; 26:150-9. [DOI: 10.1157/13116752] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
19
|
Effects of pregnancy on CYP3A and P-glycoprotein activities as measured by disposition of midazolam and digoxin: a University of Washington specialized center of research study. Clin Pharmacol Ther 2008; 84:248-53. [PMID: 18288078 DOI: 10.1038/clpt.2008.1] [Citation(s) in RCA: 176] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The objectives of the study were to evaluate the effects of pregnancy on CYP3A and P-glycoprotein (P-gp) activities, as measured by disposition of midazolam and digoxin, respectively. Thirteen women received digoxin (0.25 mg p.o.) and midazolam (2 mg p.o.) in random order, separated by 1-2 weeks at 28-32 weeks gestation, and the same order was repeated at 6-10 weeks postpartum. Plasma and urine concentrations were determined by liquid chromatography-mass spectrometry and analyzed by noncompartmental methods. Midazolam CL/F(unbound) (593 +/- 237 l/min vs. 345 +/- 103 l/min; P = 0.007), digoxin CL(Renal, unbound) (272 +/- 45 ml/min vs. 183 +/- 37 ml/min; P < 0.002) and digoxin CL(secretion,) (unbound) (109 +/- 34 ml/min vs. 58 +/- 22 ml/min; P < 0.002) were higher during pregnancy than postpartum. These data are consistent with increased hepatic and/or intestinal CYP3A and renal P-gp activities during pregnancy.
Collapse
|
20
|
Yadav S, Zajac E, Singhal SS, Awasthi S. Linking stress-signaling, glutathione metabolism, signaling pathways and xenobiotic transporters. Cancer Metastasis Rev 2007; 26:59-69. [PMID: 17260165 DOI: 10.1007/s10555-007-9043-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Multi-specific drug-transport mechanisms are intricately involved in mediating a pleiotropic drug-resistance in cancer cells by mediating drug-accumulation defects in cells in which they are over-expressed. The existence and over-expression in drug-resistant neoplasms of transporter proteins belonging to ATP-binding cassette (ABC) family indicate that these myriad transporters contribute to the multidrug-resistance phenomena by removing or sequestering of toxins and metabolites. Another prominent mechanism of multispecific drug-resistance involves glutathione and glutathione linked enzymes, particularly those of the mercapturic acid pathway, which are involved in metabolism and excretion of both endogenous and exogenous electrophilic toxins. A key step in the mercapturic acid pathway, efflux of the glutathione-electrophile conjugate has recently been shown to be catalyzed largely by the stress-responsive protein RLIP76, a splice variant peptide endowed by the human gene RALBP1. The known involvement of RLIP76 in membrane signaling pathways and endocytosis has resulted in a new paradigm for transport and metabolism related drug-resistance in which RLIP76 plays a central role. Our recent studies demonstrating a key anti-apoptotic and stress-responsive role of RLIP76, and the demonstration of dramatic response in malignancies to RLIP76 depletion indicate that targeting this mercapturic acid pathway transporter may be a highly effective and multifaceted antineoplastic strategy.
Collapse
Affiliation(s)
- Sushma Yadav
- Department of Chemistry and Biochemistry, University of Texas at Arlington, TX 76019-0065, USA
| | | | | | | |
Collapse
|
21
|
Meletiadis J, Chanock S, Walsh TJ. Human pharmacogenomic variations and their implications for antifungal efficacy. Clin Microbiol Rev 2006; 19:763-87. [PMID: 17041143 PMCID: PMC1592689 DOI: 10.1128/cmr.00059-05] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Pharmacogenomics is defined as the study of the impacts of heritable traits on pharmacology and toxicology. Candidate genes with potential pharmacogenomic importance include drug transporters involved in absorption and excretion, phase I enzymes (e.g., cytochrome P450-dependent mixed-function oxidases) and phase II enzymes (e.g., glucuronosyltransferases) contributing to metabolism, and those molecules (e.g., albumin, A1-acid glycoprotein, and lipoproteins) involved in the distribution of antifungal compounds. By using the tools of population genetics to define interindividual differences in drug absorption, distribution, metabolism, and excretion, pharmacogenomic models for genetic variations in antifungal pharmacokinetics can be derived. Pharmacogenomic factors may become especially important in the treatment of immunocompromised patients or those with persistent or refractory mycoses that cannot be explained by elevated MICs and where rational dosage optimization of the antifungal agent may be particularly critical. Pharmacogenomics has the potential to shift the paradigm of therapy and to improve the selection of antifungal compounds and adjustment of dosage based upon individual variations in drug absorption, metabolism, and excretion.
Collapse
Affiliation(s)
- Joseph Meletiadis
- Pediatric Oncology Branch, National Cancer Institute, CRC, 1-5750 10 Center Drive, Bethesda, MD 20892, USA
| | | | | |
Collapse
|
22
|
Ballestero MR, Monte MJ, Briz O, Jimenez F, Gonzalez-San Martin F, Marin JJG. Expression of transporters potentially involved in the targeting of cytostatic bile acid derivatives to colon cancer and polyps. Biochem Pharmacol 2006; 72:729-38. [PMID: 16844096 DOI: 10.1016/j.bcp.2006.06.007] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 06/07/2006] [Accepted: 06/07/2006] [Indexed: 11/23/2022]
Abstract
Drug targeting might help to overcome resistance to chemotherapy. Here we investigated whether colon cancer and polyps do express functional carriers involved in the uptake of cytostatic bile acid derivatives, in this case Bamet-UD2 [cis-diammine-bisursodeoxycholate-platinum(II)], which has been reported to be taken up by colon cancer cells "in vitro", efficiently induce apoptosis and overcome resistance to cisplatin. Although at lower levels than in ileum, a detectable expression of ASBT, OATP8/1B3, OCT1 and OSTalpha in colon tissue was found, which was not impaired in colon cancer or polyps. The expression of OATP-A/1A2 and OSTbeta was also found in colon, but this was markedly decreased in neoplastic colon tissue. In contrast, the expression of OATP-C/1B1 was low in colon but significantly enhanced in neoplastic colon tissue. MDR1 and MRP2 were poorly expressed in colon as compared with ileum, whereas MRP3 expression was higher in colon than in ileum. The abundance of mRNA for these ABC proteins was not changed in colon cancer or polyps. When RNA from different tissues was injected to Xenopus laevis oocytes their ability to take up taurocholate and Bamet-UD2 was enhanced (healthy ileum>healthy colon approximately neoplastic colon tissue). In all cases, uptake was lower for taurocholate than for Bamet-UD2, probably due to that ASBT mediates sodium-dependent uptake of both substrates, whereas additional transporters expressed in these tissues can participate in Bamet-UD2 uptake. In conclusion, our results suggest that the use of cytostatic bile acid derivatives might be a good pharmacological strategy for the treatment of colon tumors.
Collapse
Affiliation(s)
- Maria R Ballestero
- Group of Experimental Hepatology and Drug Targeting (HEVEFARM), Department of Physiology and Pharmacology, University of Salamanca, Campus Miguel de Unamuno, ED-S09, 37007 Salamanca, Spain
| | | | | | | | | | | |
Collapse
|
23
|
Kim MK, Han L, Choi MK, Han YH, Kim DD, Chung SJ, Shim CK. Dose dependency in the oral bioavailability of an organic cation model, tributylmethyl ammonium (TBuMA), in rats: Association with the saturation of efflux by the P-gp system on the apical membrane of the intestinal epithelium. J Pharm Sci 2005; 94:2644-55. [PMID: 16258993 DOI: 10.1002/jps.20456] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The oral bioavailability of tributylmethyl ammonium (TBuMA), an organic cation (OC), exhibited a dose-dependency (i.e., 17, 27, and 35% at doses of 0.4, 4, or 12 micromol/kg, respectively) in the rat. Relevant mechanisms were investigated in the present study by estimating the mucosal to serosal (m-s) and serosal to mucosal (s-m) transport of TBuMA across the rat ileum in an Ussing chamber experiment. The m-s permeability rapidly increased with TBuMA concentration in the mucosal side, and then becoming constant at high TBuMA concentrations. Various studies, including temperature- and potential-dependency and inhibition experiments, revealed that carrier-mediated transport mechanisms (most likely OCT1, OCT3, and P-gp) are involved in the s-m transport of TBuMA, and the saturation of the transport at higher concentrations is responsible for the concentration-dependency in the m-s permeability or dose-dependency of the bioavailability of TBuMA. A nonlinear regression of the m-s transport, based on the assumption of a mixed process of linear diffusion and saturable efflux, exhibited a clearance (CLlinear) of 0.343 microL/min/cm2 for the passive diffusion, and an apparent Km of 241 microM for the saturable process. The Km value is consistent with the concentration range in the intestine which is expected to be achieved after the oral dosing of TBuMA at a dose of 0.4 micromol/kg (i.e., 68 approximately 185 microM). Interestingly, the m-s transport of TBuMA was increased by the presence of P-gp substrates or inhibitors in the mucosal side, but not by the mucosal presence of OCT substrates or inhibitors, suggesting that only efflux transport systems on the apical membrane (e.g., P-gp), but not those on the serosal membrane (e.g., OCT1 and OCT3), of the intestinal epithelial cells, are involved in the dose-dependency or concentration dependency. A similar relationship seems likely for drugs that are substrates of efflux transporters on the apical membrane of the intestinal epithelium.
Collapse
Affiliation(s)
- Moon Kyoung Kim
- Department of Pharmaceutics, College of Pharmacy, Seoul National University, Shilim-9-dong, Kwanak-Gu, Seoul 151-742, Korea
| | | | | | | | | | | | | |
Collapse
|
24
|
Monte MJ, Ballestero MR, Briz O, Perez MJ, Marin JJG. Proapoptotic Effect on Normal and Tumor Intestinal Cells of Cytostatic Drugs with Enterohepatic Organotropism. J Pharmacol Exp Ther 2005; 315:24-35. [PMID: 15985617 DOI: 10.1124/jpet.105.086165] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The proapoptotic effect of cisplatin bile acid derivatives Bamet-R2 [cis-diamminechloro-cholylglycinate-platinum(II)] and Bamet-UD2 [cis-diammine-bisursodeoxycholate-platinum(II)], developed to treat liver and intestinal tumors, was investigated in vitro using human enterohepatic cells HepG2 (hepatoblastoma), LS 174T (colon adenocarcinoma), and its cisplatin-resistant subline LS 174T/R. Uptake by wild-type tumor cells was higher for Bamets than for cisplatin. In LS 174T/R cells, copper transporter-1 was down-regulated and multidrug resistance-associated protein-2 was up-regulated. Consequently, uptake and efflux of cisplatin, but not those of Bamets, were reduced and increased, respectively. The degree of necrosis (lactate dehydrogenase release) induced by these three drugs was small and similar in all cell types. In contrast, proapoptotic effect (caspase-3 activity and DNA fragmentation) was Bamet-UD2 > cisplatin > Bamet-R2 in HepG2 and LS 174T cells, but Bamet-UD2 > Bamet-R2 >> cisplatin in LS 174T/R cells. This effect was consistent with the ability of these compounds to form DNA-adducts (DNA-platination, changes in the DNA melting temperature, and MspI-induced restriction sequence cleavage). Oral administration of Bamet-UD2 to mice induced mild apoptosis in the small intestine (ileum > duodenum), which was not severe enough to modify its structure or function as determined by water absorption and glycocholic acid uptake by in situ perfused ileum. These results indicate that Bamet-UD2 overcomes the resistance to cisplatin when this is due in part to enhanced ability of intestinal tumors to reduce intracellular cisplatin contents. Moreover, its strong proapoptotic versus its weak pronecrotic effect together with its mild effect on normal tissues, including intestinal mucosa, may account for the high antitumor activity of Bamet-UD2 together with its very low toxicity.
Collapse
Affiliation(s)
- Maria J Monte
- Department of Physiology and Pharmacology, University of Salamanca, Spain
| | | | | | | | | |
Collapse
|
25
|
Lee YJ, Chung SJ, Shim CK. Limited Role of P-Glycoprotein in the Intestinal Absorption of Cyclosporin A. Biol Pharm Bull 2005; 28:760-3. [PMID: 15802827 DOI: 10.1248/bpb.28.760] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The contribution of P-glycoprotein (P-gp) to the intestinal absorption of cyclosporin A (CsA) was investigated by comparing the in vivo pharmacokinetics of CsA in P-gp knockout mice versus wild-type mice following both oral and intravenous administration and by examining the transport of CsA across Caco-2 cell monolayers. The apparent oral bioavailability of CsA in P-gp knockout mice was 1.55-fold larger than in wild-type mice, leading to an apparent absolute bioavailability of 41.8%. A concentration dependent efflux transport of CsA across Caco-2 cell monolayers was found, which exhibited saturation at a CsA concentration of 1 muM. These results suggest that the involvement of P-gp in the intestinal absorption of CsA is not as profound as was previously thought.
Collapse
Affiliation(s)
- Young-Joo Lee
- Department of Pharmaceutics, College of Pharmacy, Seoul National University, Korea
| | | | | |
Collapse
|
26
|
Kalitsky-Szirtes J, Shayeganpour A, Brocks DR, Piquette-Miller M. Suppression of drug-metabolizing enzymes and efflux transporters in the intestine of endotoxin-treated rats. Drug Metab Dispos 2004; 32:20-7. [PMID: 14709616 DOI: 10.1124/dmd.32.1.20] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Infection and inflammation impose a suppression in the expression and activity of several drug transporters and drug-metabolizing enzymes in liver. In the intestine, cytochrome P450 3A (CYP3A), P-glycoprotein (PGP/mdr1), and the multidrug resistance-associated protein 2 (MRP2) are important barriers to the absorption of many clinically important drugs; thus, the expression and activity of these proteins were examined in inflammation. Transport and metabolism were determined in jejunum segments isolated at 24 h from endotoxin-treated or control rats (n = 8) mounted in Ussing chambers. Transport and metabolism of (3)H-digoxin, 5-carboxyfluorescein (5-CF), amiodarone (AM), and 7-benzyloxyquinoline (7-BQ) were measured for 90 min in the presence and absence of inhibitors. Reverse transcription-polymerase chain reaction was used to measure mRNA levels. As compared with controls, levels of mdr1a and mrp2 mRNA were significantly decreased by approximately 50% in the jejunum of LPS-treated rats. Corresponding reductions in the basolateral-->apical efflux of digoxin, AM, and 5-CF were observed, resulting in significant increases in the apical-->basolateral absorption of these compounds. Intestinal CYP3A mRNA levels and CYP3A-mediated metabolism of 7-BQ and AM were also decreased by approximately 50 to 70% (p < 0.05) in the LPS group. Mannitol permeability and lactate dehydrogenase release were not altered. These studies indicate that endotoxin-induced inflammation imposes a reduction in the intestinal expression and activity of PGP, mrp2, and CYP3A in rats, which elicits corresponding changes in the intestinal transport and metabolism of their substrates. Hence, infection and inflammatory diseases may impose variability in drug bioavailability through alterations in the intestinal expression and activity of drug transporters and metabolic enzymes.
Collapse
Affiliation(s)
- J Kalitsky-Szirtes
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 2S2
| | | | | | | |
Collapse
|
27
|
Wang R, Lam P, Liu L, Forrest D, Yousef IM, Mignault D, Phillips MJ, Ling V. Severe cholestasis induced by cholic acid feeding in knockout mice of sister of P-glycoprotein. Hepatology 2003; 38:1489-99. [PMID: 14647060 DOI: 10.1016/j.hep.2003.09.037] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Intrahepatic cholestasis is often associated with impairment of biliary bile acid secretion, a process mediated by the sister of P-glycoprotein (Spgp or Abcb11) also known as the bile salt export pump (Bsep). In humans, mutations in the Spgp gene are associated with a fatal childhood disease, type 2 progressive familial intrahepatic cholestasis (PFIC2). However in mice, the "knockout" of Spgp only results in mild cholestasis. In this study, we fed spgp(-/-) knockout mice with a cholic acid (CA)-supplemented diet to determine whether a more pronounced PFIC2-like phenotype could be induced. Such mice developed severe cholestasis characterized by jaundice, weight loss, elevated plasma bile acid, elevated transaminase, cholangiopathy (proliferation of bile ductules and cholangitis), liver necrosis, high mortality, and wide-ranging changes in the mRNA expression of major liver genes (16/36 examined). A surprising observation was that the bile acid output and bile flow in CA-fed mutant mice was significantly higher than anticipated. This suggests that the spgp(-/-) mice are able to utilize an alternative bile salt transport system. However, unlike Spgp, this system is insufficient to protect the knockout mice from cholestasis despite its high capacity. In conclusion, the spgp(-/-) mice provide a unique model to investigate molecular pathways associated with cholestasis and related diseases.
Collapse
Affiliation(s)
- Renxue Wang
- British Columbia Cancer Research Center, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Pang KS. MODELING OF INTESTINAL DRUG ABSORPTION: ROLES OF TRANSPORTERS AND METABOLIC ENZYMES (FOR THE GILLETTE REVIEW SERIES). Drug Metab Dispos 2003; 31:1507-19. [PMID: 14625347 DOI: 10.1124/dmd.31.12.1507] [Citation(s) in RCA: 193] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- K Sandy Pang
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada.
| |
Collapse
|
29
|
Arimori K, Kuroki N, Hidaka M, Iwakiri T, Yamsaki K, Okumura M, Ono H, Takamura N, Kikuchi M, Nakano M. Effect of P-glycoprotein modulator, cyclosporin A, on the gastrointestinal excretion of irinotecan and its metabolite SN-38 in rats. Pharm Res 2003; 20:910-7. [PMID: 12817897 DOI: 10.1023/a:1023847521767] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The purpose of this work was to investigate the role of the hepatic and intestinal P-glycoprotein (P-gp) and canalicular multispecific organic anion transporter/multidrug resistance-associated protein 2 (cMOAT/MRP2) on both biliary excretion and intestinal exsorption of irinotecan hydrochloride (CPT-11) and its metabolite, SN-38, in the lactone and carboxylate forms. Cyclosporin A (CsA) was used to modulate P-gp and cMOAT/MRP2. METHODS The transcellular transport of CPT-11 and SN-38 was examined by using LLC-PK1 derivative cell lines transfected with murine mdrla both in the absence or in the presence of CsA. The excretions of the compounds through the biliary and intestinal membrane routes were investigated by in situ perfusion technique. RESULTS Basolateral-to-apical transport of CPT-11 lactone in L-mdr1a cells was significantly decreased by CsA (10 microM). The transcellular transport of SN-38 lactone showed similar behaviors as those of CPT-11 lactone. The biliary excretion and the intestinal exsorption of both forms of CPT-11 and SN-38 were significantly inhibited when the drug was co-administered with CsA. CONCLUSIONS The transports of CPT-11 and SN-38 via the biliary route seem to be essentially related with cMOAT/MRP2, whereas those of both compounds via the intestinal membrane seem to be related with P-gp.
Collapse
Affiliation(s)
- Kazuhiko Arimori
- Department of Pharmacy, Miyazaki Medical College, 5200 Kihara, Kiyotake-cho, Miyazaki-gun, Miyazaki 889-1692, Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Abstract
P-glycoprotein, the most extensively studied ATP-binding cassette (ABC) transporter, functions as a biological barrier by extruding toxins and xenobiotics out of cells. In vitro and in vivo studies have demonstrated that P-glycoprotein plays a significant role in drug absorption and disposition. Because of its localisation, P-glycoprotein appears to have a greater impact on limiting cellular uptake of drugs from blood circulation into brain and from intestinal lumen into epithelial cells than on enhancing the excretion of drugs out of hepatocytes and renal tubules into the adjacent luminal space. However, the relative contribution of intestinal P-glycoprotein to overall drug absorption is unlikely to be quantitatively important unless a very small oral dose is given, or the dissolution and diffusion rates of the drug are very slow. This is because P-glycoprotein transport activity becomes saturated by high concentrations of drug in the intestinal lumen. Because of its importance in pharmacokinetics, P-glycoprotein transport screening has been incorporated into the drug discovery process, aided by the availability of transgenic mdr knockout mice and in vitro cell systems. When applying in vitro and in vivo screening models to study P-glycoprotein function, there are two fundamental questions: (i) can in vitro data be accurately extrapolated to the in vivo situation; and (ii) can animal data be directly scaled up to humans? Current information from our laboratory suggests that in vivo P-glycoprotein activity for a given drug can be extrapolated reasonably well from in vitro data. On the other hand, there are significant species differences in P-glycoprotein transport activity between humans and animals, and the species differences appear to be substrate-dependent. Inhibition and induction of P-glycoprotein have been reported as the causes of drug-drug interactions. The potential risk of P-glycoprotein-mediated drug interactions may be greatly underestimated if only plasma concentration is monitored. From animal studies, it is clear that P-glycoprotein inhibition always has a much greater impact on tissue distribution, particularly with regard to the brain, than on plasma concentrations. Therefore, the potential risk of P-glycoprotein-mediated drug interactions should be assessed carefully. Because of overlapping substrate specificity between cytochrome P450 (CYP) 3A4 and P-glycoprotein, and because of similarities in P-glycoprotein and CYP3A4 inhibitors and inducers, many drug interactions involve both P-glycoprotein and CYP3A4. Unless the relative contribution of P-glycoprotein and CYP3A4 to drug interactions can be quantitatively estimated, care should be taken when exploring the underlying mechanism of such interactions.
Collapse
Affiliation(s)
- Jiunn H Lin
- Department of Drug Metabolism, Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
| | | |
Collapse
|
31
|
Trauner M, Boyer JL. Bile salt transporters: molecular characterization, function, and regulation. Physiol Rev 2003; 83:633-71. [PMID: 12663868 DOI: 10.1152/physrev.00027.2002] [Citation(s) in RCA: 661] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Molecular medicine has led to rapid advances in the characterization of hepatobiliary transport systems that determine the uptake and excretion of bile salts and other biliary constituents in the liver and extrahepatic tissues. The bile salt pool undergoes an enterohepatic circulation that is regulated by distinct bile salt transport proteins, including the canalicular bile salt export pump BSEP (ABCB11), the ileal Na(+)-dependent bile salt transporter ISBT (SLC10A2), and the hepatic sinusoidal Na(+)- taurocholate cotransporting polypeptide NTCP (SLC10A1). Other bile salt transporters include the organic anion transporting polypeptides OATPs (SLC21A) and the multidrug resistance-associated proteins 2 and 3 MRP2,3 (ABCC2,3). Bile salt transporters are also present in cholangiocytes, the renal proximal tubule, and the placenta. Expression of these transport proteins is regulated by both transcriptional and posttranscriptional events, with the former involving nuclear hormone receptors where bile salts function as specific ligands. During bile secretory failure (cholestasis), bile salt transport proteins undergo adaptive responses that serve to protect the liver from bile salt retention and which facilitate extrahepatic routes of bile salt excretion. This review is a comprehensive summary of current knowledge of the molecular characterization, function, and regulation of bile salt transporters in normal physiology and in cholestatic liver disease and liver regeneration.
Collapse
Affiliation(s)
- Michael Trauner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Karl-Franzens University, School of Medicine, Graz, Austria
| | | |
Collapse
|
32
|
Abstract
P-glycoprotein (P-gp), the most extensively studied ATP-binding cassette transporter, functions as a biological barrier by extruding toxic substances and xenobiotics out of cells. In vitro and in vivo studies have demonstrated that P-gp plays a significant role in drug absorption and disposition. Like cytochrome P450 enzymes, inhibition and induction of P-gp have been reported as the causes of drug-drug interactions. Because many prototypic inhibitors and inducers affect both CYP3A4 and P-gp, many drug interactions caused by these inhibitors and inducers involve these two systems. Clinically, it is very difficult to quantitatively differentiate P-gp-mediated drug interactions versus CYP3A4-mediated drug interactions, unless their relative contributions can be accurately estimated. Therefore, care should be exercised when interpreting drug interaction data and exploring the underlying mechanisms of drug interactions.
Collapse
Affiliation(s)
- Jiunn H Lin
- Department of Drug Metabolism, Merck Research Laboratories, WP75A-203, West Point, PA 19486, USA.
| |
Collapse
|
33
|
Zhang Y, Bachmeier C, Miller DW. In vitro and in vivo models for assessing drug efflux transporter activity. Adv Drug Deliv Rev 2003; 55:31-51. [PMID: 12535573 DOI: 10.1016/s0169-409x(02)00170-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Determining the activity of drug efflux transport proteins has important implications in the identification of substrates and/or inhibitors of the various transport systems, as well as mechanistic determination of localization, and functional role of the transporters in absorption, distribution and elimination of compounds in the body. This review examines both in vitro and in vivo approaches used to determine drug efflux transporter activity, their applications, and advantages and potential limitations.
Collapse
Affiliation(s)
- Yan Zhang
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | | | | |
Collapse
|
34
|
Abstract
Over the past decade, enormous progress has been made in identifying the mechanisms that underlie hepatobiliary excretion. A set of transport proteins mediates the canalicular transport of most important bile constituents. With the discovery of these transporter genes, the mechanism of bile formation could be partly elucidated and genetic defects caused by mutations in these genes identified. This progress is crucial not only for paediatric and adult hepatology, but also for pharmacology, because the characterization of these transport systems provides tools for the prediction of the pharmacokinetics of drugs. Indeed, there is a growing interest on the part of the pharmaceutical industry for research into transport systems in general and hepatobiliary secretion in particular. For all of these transporter genes, knockout mice have been bred that allow one to assess the in vivo function of each of these transporters with regard to their role in physiology and drug elimination.
Collapse
Affiliation(s)
- Ronald P J Oude Elferink
- Laboratory of Experimental Hepatology, AMC Liver Center, Academic Medical Center, Amsterdam, The Netherlands
| |
Collapse
|
35
|
Erickson RP, Kiela M, Devine PJ, Hoyer PB, Heidenreich RA. mdr1a deficiency corrects sterility in Niemann-Pick C1 protein deficient female mice. Mol Reprod Dev 2002; 62:167-73. [PMID: 11984826 DOI: 10.1002/mrd.10093] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Niemann-Pick type C disease is a progressive neurological disease with cholesterol storage in liver, and npc1-/- mice share these features and are sterile. We have searched for the cause of sterility and found normal folliculogenesis and progesterone levels but lack of implantation. Multiple drug resistance (MDR) P-glycoproteins are plasma membrane proteins implicated in the movement of drugs and lipids across membranes. Their functions are inhibited by progesterone, which has been shown to alter cellular cholesterol homeostasis and has implicated P-glycoproteins in the movement of cholesterol to the endoplasmic reticulum. We have introduced the mdr1a knockout into the npc1 mutant line. While the neurological disease continues at its usual rate, preventing the females from taking care of their litters, npc1-/-, mdr1a-/- females became fertile. Although the mdr1a P-glycoprotein co-localizes with caveolae, neither caveolin-1 nor npc1 levels were significantly altered in the livers of double homozygotes. The absence of mdr1a was confirmed by immunoblotting, but npc1 deficiency was not associated with consistent changes in cerebellar mdr1a in mdr1a+/+ mice. The results show that a mdr1a mutation is an in vivo suppressor of female sterility in npc1 deficient mice.
Collapse
Affiliation(s)
- Robert P Erickson
- Department of Pediatrics, Section of Medical and Molecular Genetics, Angel Charity for Children-Wings for Genetic Research, Steele Memorial Children's Research Center, Arizona, USA.
| | | | | | | | | |
Collapse
|
36
|
Little JM, Williams L, Xu J, Radominska-Pandya A. Glucuronidation of the dietary fatty acids, phytanic acid and docosahexaenoic acid, by human UDP-glucuronosyltransferases. Drug Metab Dispos 2002; 30:531-3. [PMID: 11950783 DOI: 10.1124/dmd.30.5.531] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Linoleic acid has recently been shown to be glucuronidated in vitro by human liver and intestinal microsomes and recombinant UGT2B7. In the present study, the dietary fatty acids (FA), phytanic acid (PA), and docosahexaenoic acid (DHA) have been used as substrates for human UDP-glucuronosyltransferases (UGTs). Both compounds were effectively glucuronidated by human liver microsomes (HLM; 1.25 +/- 0.36 and 1.12 +/- 0.32 nmol/mg x min for PA and DHA, respectively) and UGT2B7 (0.71 and 0.53 nmol/mg x min). Kinetic analysis produced relatively low K(m) values for PA with both HLM and UGT2B7 (149 and 108 microM, respectively). The K(m) for DHA glucuronidation by HLM (460 microM) was considerably higher than that for UGT2B7 (168 microM), suggesting the involvement in microsomes of other UGT isoforms in addition to UGT2B7. Glucuronidation of PA and DHA by gastrointestinal microsomes from 16 human subjects was determined. In general, both PA and DHA were glucuronidated by gastric and intestinal microsomes, and activity toward both substrates was lowest in the stomach, increased in the small intestine, and lower in the colon. However, there were large interindividual variations in UGT activity toward both substrates in all segments of the intestine, as has been seen with other substrates. Thus, PA and DHA are effective in vitro substrates for human liver, gastric and intestinal microsomes, and glucuronidation may play a role in modulating the availability of these FA as ligands for nuclear receptors.
Collapse
Affiliation(s)
- Joanna M Little
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
| | | | | | | |
Collapse
|
37
|
Brinkmann U, Eichelbaum M. Polymorphisms in the ABC drug transporter gene MDR1. THE PHARMACOGENOMICS JOURNAL 2002; 1:59-64. [PMID: 11913728 DOI: 10.1038/sj.tpj.6500001] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In addition to genetically variable metabolic enzymes such as Cyp p450 proteins, blood and tissue levels of many drugs are influenced by controlled transport across compartmental boundaries. Major determinants in these transport processes are ATP-dependent efflux pumps such as P-glycoprotein and related proteins (eg MRPs), which can influence the bioavailability and CNS concentrations, as well as disposition of drugs. In addition to its recognized role in the development of multiple chemotherapy resistances, experimental evidence for the relevant influence of the MDR1 gene encoded P-glycoprotein, on the pharmacology of many other drugs has been gathered by the analyses of knockout mice, as well as in clinical studies. Recently, functional genetic polymorphisms in the MDR1 gene have been identified which influence the distribution and bioavailability of PGP substrates.
Collapse
Affiliation(s)
- U Brinkmann
- Epidauros Biotechnology, Pharmacogenetics Labs., Bernried, Germany.
| | | |
Collapse
|
38
|
Hooiveld GJEJ, Heegsma J, Montfoort JEV, Jansen PLM, Meijer DKF, Müller M. Stereoselective transport of hydrophilic quaternary drugs by human MDR1 and rat Mdr1b P-glycoproteins. Br J Pharmacol 2002; 135:1685-94. [PMID: 11934808 PMCID: PMC1573286 DOI: 10.1038/sj.bjp.0704620] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2001] [Revised: 01/18/2002] [Accepted: 01/22/2002] [Indexed: 11/08/2022] Open
Abstract
1. The present study was performed to evaluate and compare the ability of human MDR1-, and rat Mdr1b- and Mdr2-P-glycoproteins to transport hydrophilic monoquaternary drugs. Transport studies were performed with plasma membrane vesicles isolated from MDR1-, Mdr1b-, or Mdr2-overexpressing insect cells. 2. As model substrates we used the N-methylated derivatives of the diastereomers quinidine and quinine, the monoquaternary compounds N-methylquinidine and N-methylquinine. Vincristine, an established MDR1 substrate, was used as a reference. 3. We observed ATP-dependent uptake of all drugs studied into MDR1- and Mdr1b-expressing vesicles. Mdr2 was not able to transport these compounds. MDR1- and Mdr1b-mediated transport was saturable, and could be inhibited by various drugs, including PSC-833. 4. For both MDR1 and Mdr1b the V(max)/K(m) ratios (or clearance) of N-methylquinidine were greater than those determined for N-methylquinine. This stereoselective difference was also evident from differential inhibitory studies with the two isomers. 5. Comparison of normalized clearance indicated that human MDR1 was more effective in transporting the tested substrates than rat Mdr1b. 6. In conclusion, our results demonstrate that MDR1 and Mdr1b, but not Mdr2, are able to transport the monoquaternary model drugs; both MDR1 and Mdr1b display stereospecificity for these cations; and indicate human MDR1 is more efficient in transporting these cations than its rat orthologue Mdr1b.
Collapse
Affiliation(s)
- Guido J E J Hooiveld
- Groningen University Institute for Drug Exploration, Division of Gastroenterology and Hepatology, University Hospital Groningen, Hanzeplein 1, NL-9713 GZ, Groningen, The Netherlands
- Department of Pharmacokinetics and Drug Delivery, University Centre for Pharmacy, A. Deusinglaan 1, NL-9713 AW, Groningen, The Netherlands
| | - Janette Heegsma
- Groningen University Institute for Drug Exploration, Division of Gastroenterology and Hepatology, University Hospital Groningen, Hanzeplein 1, NL-9713 GZ, Groningen, The Netherlands
- Department of Pharmacokinetics and Drug Delivery, University Centre for Pharmacy, A. Deusinglaan 1, NL-9713 AW, Groningen, The Netherlands
| | - Jessica E van Montfoort
- Department of Pharmacokinetics and Drug Delivery, University Centre for Pharmacy, A. Deusinglaan 1, NL-9713 AW, Groningen, The Netherlands
- Division of Clinical Pharmacology and Toxicology, University Hospital Zürich, CH-8091 Zürich, Switzerland
| | - Peter L M Jansen
- Groningen University Institute for Drug Exploration, Division of Gastroenterology and Hepatology, University Hospital Groningen, Hanzeplein 1, NL-9713 GZ, Groningen, The Netherlands
| | - Dirk K F Meijer
- Department of Pharmacokinetics and Drug Delivery, University Centre for Pharmacy, A. Deusinglaan 1, NL-9713 AW, Groningen, The Netherlands
| | - Michael Müller
- Groningen University Institute for Drug Exploration, Division of Gastroenterology and Hepatology, University Hospital Groningen, Hanzeplein 1, NL-9713 GZ, Groningen, The Netherlands
| |
Collapse
|
39
|
MESH Headings
- ATP Binding Cassette Transporter, Subfamily B/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP-Binding Cassette Transporters/genetics
- Genes, MDR/genetics
- Humans
- Pharmaceutical Preparations/metabolism
- Terminology as Topic
- Tissue Distribution
Collapse
Affiliation(s)
- Richard B Kim
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6602, USA.
| |
Collapse
|
40
|
Brinkmann U, Roots I, Eichelbaum M. Pharmacogenetics of the human drug-transporter gene MDR1: impact of polymorphisms on pharmacotherapy. Drug Discov Today 2001; 6:835-839. [PMID: 11495756 DOI: 10.1016/s1359-6446(01)01892-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The blood- and tissue-concentrations, and thus the activity, of many drugs are influenced by factors that are subject to inter-individual variation. Variables that influence blood levels are metabolizing enzymes and transporters. Transporters control drug uptake, distribution and elimination. Transport by efflux pumps such as MDR1-encoded P-glycoprotein can influence the bioavailability of drugs. Knowledge of the transporter 'status' might allow for compensation of differences in drug uptake, such as by dose adjustment, which is important for drugs with narrow therapeutic windows. So far, intestinal expression of MDR1 has been determined by cumbersome methods, such as biopsies, although recently a functional polymorphism has been identified, which discriminates individual high or low-expressor alleles. As a result, clinical trials and therapy can be adapted to the 'MDR1-status' of individual patients.
Collapse
Affiliation(s)
- U Brinkmann
- Epidauros Biotechnology, Pharmacogenetics Labs, Am Neuland 1, D-82347, Bernried, Germany
| | | | | |
Collapse
|
41
|
Matheny CJ, Lamb MW, Brouwer KR, Pollack GM. Pharmacokinetic and pharmacodynamic implications of P-glycoprotein modulation. Pharmacotherapy 2001; 21:778-96. [PMID: 11444575 DOI: 10.1592/phco.21.9.778.34558] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
P-glycoprotein (P-gp) is a cell membrane-associated protein that transports a variety of drug substrates. Although P-gp has been studied extensively as a mediator of multidrug resistance in cancer, only recently has the role of P-gp expressed in normal tissues as a determinant of drug pharmacokinetics and pharmacodynamics been examined. P-glycoprotein is present in organ systems that influence drug absorption (intestine), distribution to site of action (central nervous system and leukocytes), and elimination (liver and kidney), as well as several other tissues. Many marketed drugs inhibit P-gp function, and several compounds are under development as P-gp inhibitors. Similarly, numerous drugs can induce P-gp expression. While P-gp induction does not have a therapeutic role, P-gp inhibition is an attractive therapeutic approach to reverse multidrug resistance. Clinicians should recognize that P-gp induction or inhibition may have a substantial effect on the pharmacokinetics and pharmacodynamics of concomitantly administered drugs that are substrates for this transporter.
Collapse
Affiliation(s)
- C J Matheny
- Division of Drug Delivery and Disposition, School of Pharmacy, University of North Carolina at Chapel Hill, 27599-7360, USA
| | | | | | | |
Collapse
|
42
|
Mahmood B, Daood MJ, Hart C, Hansen TW, Watchko JF. Ontogeny of P-glycoprotein in mouse intestine, liver, and kidney. J Investig Med 2001; 49:250-7. [PMID: 11352182 DOI: 10.2310/6650.2001.33969] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND P-glycoprotein (Pgp) is an ATP-dependent, integral plasma-membrane efflux pump that is constitutively expressed on (i) adult apical brush-border epithelial cells of the intestine, (ii) the bile canalicular face of hepatocytes, and (iii) the brush border epithelium of renal proximal tubules. This Pgp tissue distribution and localization affects the absorption, distribution, metabolism, and excretion of Pgp substrates. Little is known regarding the ontogeny of Pgp expression in these tissues. METHODS Postnatal expression of Pgp on brush border membranes of small intestine, liver, and kidney as a function of maturity from birth through adulthood was determined using Western immunoblotting and immunohistochemical techniques. Tissue was isolated from FVB mice at four different ages: day of life 0 (D0), day of life 7 (D7), day of life 21 (D21), and adult (Ad). The relative expression of Pgp protein on Western immunoblots was assessed by scanning densitometry and indexed as a percentage (mean+/-SEM) of the adult levels. RESULTS On Western immunoblots, Pgp expression was limited at birth (19+/-6% of Ad) and increased significantly with maturation in intestine (ANOVA, P<0.005). In contrast, hepatic (113+/-12% of Ad) and renal (96+/-15% of Ad) Pgp expression were at adult levels at birth. The tissue-specific developmental pattern of Pgp expression was confirmed by immunohistochemistry. CONCLUSIONS We conclude that Pgp is expressed in a tissue-specific and developmentally regulated fashion and speculate that developmental modulation of intestine-Pgp expression may affect the oral bioavailability of Pgp substrates.
Collapse
Affiliation(s)
- B Mahmood
- Department of Pediatrics, Magee-Womens Research Institute, University of Pittsburgh School of Medicine, PA, USA
| | | | | | | | | |
Collapse
|
43
|
Jude AR, Little JM, Czernik PJ, Tephly TR, Grant DF, Radominska-Pandya A. Glucuronidation of linoleic acid diols by human microsomal and recombinant UDP-glucuronosyltransferases: identification of UGT2B7 as the major isoform involved. Arch Biochem Biophys 2001; 389:176-86. [PMID: 11339806 DOI: 10.1006/abbi.2001.2344] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent reports suggest that linoleic acid (LA) epoxides and diols are associated with important physiological, pharmacological, and pathological events in vivo. We have shown recently that LA-diols are excellent substrates for human liver microsomal UDP-glucuronosyltransferases (UGTs); however, it is not known if other human tissues glucuronidate LA-diols or which UGT isozyme(s) is involved. The present studies with human intestinal microsomes indicate that glucuronidation of LA-diols occurs throughout the gastrointestinal tract, with the highest activity in the small intestine. LA-diols yielded exclusively hydroxyl-linked glucuronides, whereas LA yielded the carboxyl-linked glucuronide. Studies with human recombinant UGTs demonstrated that only UGT2B7 glucuronidated LA and LA-diols. Kinetic analysis with UGT2B7 yielded apparent K(m) values in the range of 40-70 microM and V(max) values from 4.5 to 5.4 nmol/mg x min. These studies indicate that LA and LA-diols are excellent substrates for intestinal UGTs and provide the first evidence for UGT2B7 being the major isoform involved.
Collapse
Affiliation(s)
- A R Jude
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock 72205, USA
| | | | | | | | | | | |
Collapse
|
44
|
Abstract
Transgenic technology has made it possible to alter the genetic make-up of a laboratory mouse through the removal or insertion of selected genes. The resulting transgenic mouse provides a means for determining the developmental and functional contributions of selected genes and the proteins they encode. The current article reviews examples of the use of transgenic mice in pharmacokinetic and pharmacodynamic studies. In addition to examining current applications of transgenic technology in the areas of pharmacokinetics and pharmacodynamics, the potential for future advancements as well as limitations of the technology are discussed.
Collapse
Affiliation(s)
- W F Elmquist
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | | |
Collapse
|
45
|
Dresser MJ, Leabman MK, Giacomini KM. Transporters involved in the elimination of drugs in the kidney: organic anion transporters and organic cation transporters. J Pharm Sci 2001; 90:397-421. [PMID: 11170032 DOI: 10.1002/1520-6017(200104)90:4<397::aid-jps1000>3.0.co;2-d] [Citation(s) in RCA: 219] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Transporters in the kidney mediate the secretion or reabsorption of many compounds and thereby influence the plasma levels of their substrates. Organic anion transporters and organic cation transporters are two major classes of secretory transporters in the mammalian kidney. During the past decade, significant progress has been made in the cloning, functional expression, and initial characterization of these transporters. To date, five organic cation transporters and nine organic anion transporters have been cloned. In this review, we summarize the available data on organic anion and organic cation transporters, focusing in particular on their molecular characteristics, tissue distribution, and inhibitor and substrate selectivities. Currently we have a good understanding of the inhibitor selectivities for most of these transporters, and with the development of more robust assays, we will soon have a better understanding of their substrate selectivities. Based on the available data, summarized in this review, it appears that many compounds interact with multiple transporters. Furthermore, there appears to be substantial overlap in the selectivities of organic cation transporters, and the same appears true for organic anion transporters. At the present time, it is unclear what the roles of these multiple transporters are in renal drug elimination. With the development of new assays, reagents, and experimental methods, we will soon have a better understanding of the roles of each transporter isoform in the renal elimination of drugs.
Collapse
Affiliation(s)
- M J Dresser
- Department of Biopharmaceutical Sciences, University of California San Francisco, 513 Parnassus Avenue, S-926, San Francisco, CA 94143-0446, USA
| | | | | |
Collapse
|
46
|
Abstract
The importance of specific transport in toxicology is becoming increasingly clear and the work on P-glycoprotein has certainly been a major contribution to these growing insights. P-Glycoproteins were discovered by their ability to confer multidrug resistance in mammalian tumour cells. They are localised in the cell membrane where they actively extrude a wide range of compounds including many anti-cancer drugs from the cell. Besides in tumour cells, drug-transporting P-glycoproteins are also expressed in a polarised fashion in normal tissues that perform an excretory or barrier function, such as the liver, kidneys, intestines, brain endothelial cells. Based on this expression profile, it has been proposed that P-glycoproteins are important in protecting the host by reducing exposure to xenobiotics. Further studies with P-glycoprotein knockout mice have clearly established this protective function. In general, the clearance of substrate drugs is lower in knockout mice due to a diminished hepatobiliary excretion, direct intestinal excretion and/or increased enterohepatic cycling. Moreover, their uptake in sanctuary sites, such as the brain or the foetus, was profoundly higher in P-glycoprotein knockout mice, as was the uptake of drugs from the gastro-intestinal tract into the systemic circulation following oral ingestion. These results clearly highlight the impact that transport proteins can play in toxicology.
Collapse
Affiliation(s)
- O van Tellingen
- Department of Clinical Chemistry, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Huis, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
| |
Collapse
|
47
|
Kerb R, Hoffmeyer S, Brinkmann U. ABC drug transporters: hereditary polymorphisms and pharmacological impact in MDR1, MRP1 and MRP2. Pharmacogenomics 2001; 2:51-64. [PMID: 11258197 DOI: 10.1517/14622416.2.1.51] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Transport by ATP-dependent efflux pumps, such as P-glycoprotein (PGP) and multi-drug resistance related proteins (MRPs), influences bioavailability and disposition of drugs. These efflux pumps serve as defence mechanisms and determine bioavailability and CNS concentrations of many drugs. However, despite the fact that substantial data have been accumulated on the structure, function and pharmacological role of ABC transporters and even though modification of PGP function is an important mechanism of drug interactions and adverse effects in humans, there is a striking lack of data on variability of the underlying genes. This review focuses on the human drug transporter proteins PGP (MDR1) and the multi-drug resistance proteins MRP1 and MRP2. An overview is provided of pharmacologically relevant genetic, structural and functional data as well as on hereditary polymorphisms, their phenotypical consequences and pharmacological implications.
Collapse
Affiliation(s)
- R Kerb
- Epidauros Biotechnology, Pharmacogenetics Laboratory, Am Neuland 1, D-82347 Bernried, Germany
| | | | | |
Collapse
|
48
|
Hooiveld GJ, van Montfoort JE, Meijer DK, Müller M. Function and regulation of ATP-binding cassette transport proteins involved in hepatobiliary transport. Eur J Pharm Sci 2001; 12:525-43. [PMID: 11231121 DOI: 10.1016/s0928-0987(01)00101-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Hepatobiliary transport of endogenous and exogenous compounds is mediated by the coordinated action of multiple transport systems present at the sinusoidal (basolateral) and canalicular (apical) membrane domains of hepatocytes. During the last few years many of these transporters have been cloned and functionally characterized. In addition, the molecular bases of several forms of cholestatic liver disease have been defined. Combined, this has greatly expanded our understanding of the normal physiology of bile formation, the pathophysiology of intrahepatic cholestasis, as well as of drug elimination and disposition processes. In this review recent advances, with respect to function and regulation of ATP binding cassette transport proteins expressed in liver, are summarized and discussed.
Collapse
Affiliation(s)
- G J Hooiveld
- Groningen University Institute for Drug Exploration, Department of Pharmacokinetics and Drug Delivery, University of Groningen, Groningen, The Netherlands
| | | | | | | |
Collapse
|
49
|
Blackmore CG, McNaughton PA, van Veen HW. Multidrug transporters in prokaryotic and eukaryotic cells: physiological functions and transport mechanisms. Mol Membr Biol 2001; 18:97-103. [PMID: 11396617 DOI: 10.1080/09687680010030200] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Multidrug transporters mediate the extrusion of structurally unrelated drugs from prokaryotic and eukaryotic cells. As a result of this efflux activity, the cytoplasmic drug concentration in the cell is lowered to subtoxic levels and, hence, cells become multidrug resistant. The activity of multidrug transporters interferes with the drug-based control of tumours and infectious pathogenic microorganisms. There is an urgent need to understand the structure-function relationships in multidrug transporters that underlie their drug specificity and transport mechanism. Knowledge about the architecture of drug and modulator binding sites and the link between energy-generating and drug translocating functions of multidrug transporters may allow one to rationally design new drugs that can poison or circumvent the activity of these transport proteins. Furthermore, if one is to inhibit multidrug transporters in human cells, one should know more about their physiological substrates and functions. This review will summarize important new insights into the role that multidrug transporters in general, and P-glycoprotein and its bacterial homologue LmrA in particular, play in the physiology of the cell. In addition, the molecular basis of drug transport by these proteins will be discussed.
Collapse
Affiliation(s)
- C G Blackmore
- Department of Pharmacology, University of Cambridge, UK
| | | | | |
Collapse
|
50
|
Eisenbraun MD, Mosley RL, Teitelbaum DH, Miller RA. Altered development of intestinal intraepithelial lymphocytes in P-glycoprotein-deficient mice. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2000; 24:783-795. [PMID: 10906391 DOI: 10.1016/s0145-305x(00)00029-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Intraepithelial lymphocytes (IEL) that reside in the intestinal epithelium are known to exhibit phenotypic and functional characteristics that are distinct from other T cells. We have recently shown that peripheral T cells exclusively express an isoform of P-glycoprotein (P-gp) encoded by the mdr1a gene, but do not require mdr1a expression for normal proliferative, cytokine, or cytotoxic responses. In the present study, we have used mdr1-type knockout (KO) mice to demonstrate that IEL also utilize mdr1a, but only preferentially, in that the mdr1b isoform can be expressed in the absence of mdr1a expression. We also report that a high level of P-gp activity appears to be necessary for the normal development of certain IEL subpopulations. In specific, while the total number of IEL was relatively unaffected by the absence of mdr1a expression, the proportions of CD8 alpha beta and TCR alpha beta+ IEL increased significantly in mdr1a and mdr1a/b KO mice at the expense of CD8 alpha alpha and TCR gamma delta+ IEL, respectively. Moreover, these subset alterations also appeared to have functional consequences, in that proliferative, IL-2, and IFN-gamma responses of IEL from KO mice were distinct from those of normal IEL. In summary, our data suggest that mdr1a expression is required for the development of certain IEL subpopulations, most notably TCR gamma delta+ cells, and thereby indirectly influences the balance of T cell subsets in the intestinal epithelium.
Collapse
MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/deficiency
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/immunology
- Animals
- CD8 Antigens/analysis
- Carcinogens/pharmacology
- Enzyme-Linked Immunosorbent Assay
- Epithelium/immunology
- Flow Cytometry
- Interferon-gamma/analysis
- Interleukin-2/analysis
- Intestines/immunology
- Ionomycin/pharmacology
- Ionophores/pharmacology
- Lymph Nodes/immunology
- Lymphocyte Activation/drug effects
- Lymphocytes/immunology
- Male
- Mice
- Mice, Knockout
- Receptors, Antigen, T-Cell, alpha-beta/analysis
- Receptors, Antigen, T-Cell, gamma-delta/analysis
- Specific Pathogen-Free Organisms
- Tetradecanoylphorbol Acetate/pharmacology
Collapse
Affiliation(s)
- M D Eisenbraun
- Cellular and Molecular Biology Graduate Program, University of Michigan School of Medicine, Ann Arbor 48109-0949, USA
| | | | | | | |
Collapse
|