1
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Marie S, Frost KL, Hau RK, Martinez-Guerrero L, Izu JM, Myers CM, Wright SH, Cherrington NJ. Predicting disruptions to drug pharmacokinetics and the risk of adverse drug reactions in non-alcoholic steatohepatitis patients. Acta Pharm Sin B 2023; 13:1-28. [PMID: 36815037 PMCID: PMC9939324 DOI: 10.1016/j.apsb.2022.08.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/29/2022] [Accepted: 08/03/2022] [Indexed: 12/18/2022] Open
Abstract
The liver plays a central role in the pharmacokinetics of drugs through drug metabolizing enzymes and transporters. Non-alcoholic steatohepatitis (NASH) causes disease-specific alterations to the absorption, distribution, metabolism, and excretion (ADME) processes, including a decrease in protein expression of basolateral uptake transporters, an increase in efflux transporters, and modifications to enzyme activity. This can result in increased drug exposure and adverse drug reactions (ADRs). Our goal was to predict drugs that pose increased risks for ADRs in NASH patients. Bibliographic research identified 71 drugs with reported ADRs in patients with liver disease, mainly non-alcoholic fatty liver disease (NAFLD), 54 of which are known substrates of transporters and/or metabolizing enzymes. Since NASH is the progressive form of NAFLD but is most frequently undiagnosed, we identified other drugs at risk based on NASH-specific alterations to ADME processes. Here, we present another list of 71 drugs at risk of pharmacokinetic disruption in NASH, based on their transport and/or metabolism processes. It encompasses drugs from various pharmacological classes for which ADRs may occur when used in NASH patients, especially when eliminated through multiple pathways altered by the disease. Therefore, these results may inform clinicians regarding the selection of drugs for use in NASH patients.
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Affiliation(s)
- Solène Marie
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Kayla L. Frost
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Raymond K. Hau
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Lucy Martinez-Guerrero
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Jailyn M. Izu
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Cassandra M. Myers
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Stephen H. Wright
- College of Medicine, Department of Physiology, University of Arizona, Tucson, AZ 85724, USA
| | - Nathan J. Cherrington
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA,Corresponding author. Tel.: +1 520 6260219; fax: +1 520 6266944.
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2
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Nies AT, Schaeffeler E, Schwab M. Hepatic solute carrier transporters and drug therapy: Regulation of expression and impact of genetic variation. Pharmacol Ther 2022; 238:108268. [DOI: 10.1016/j.pharmthera.2022.108268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/25/2022] [Accepted: 08/15/2022] [Indexed: 11/30/2022]
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3
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Khodadadi M, Jafari-Gharabaghlou D, Zarghami N. An update on mode of action of metformin in modulation of meta-inflammation and inflammaging. Pharmacol Rep 2022; 74:310-322. [PMID: 35067907 DOI: 10.1007/s43440-021-00334-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/11/2021] [Accepted: 10/13/2021] [Indexed: 12/13/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is the most common chronic metabolic condition. Several genetic and environmental factors are involved in developing T2DM. Aging, inflammation, and obesity are the main contributors to the initiation of T2DM. They cause chronic sterile meta-inflammation and insulin resistance, thereby making a person more susceptible to developing T2DM. Metformin, a natural cationic biguanide, is widely used as the first-line treatment of T2DM. The exact action mechanism behind the glucose-lowering effect of metformin is not clear, but, presumably, metformin utilizes a broad spectrum of molecular mechanisms to control blood glucose including decreasing intestinal glucose absorption, inhibition of the hepatic gluconeogenesis, decreasing insulin resistance, etc. Recent studies have shown that metformin exerts its effects through the inhibition of mitochondrial respiratory chain complex 1 and the AMP-activated protein kinase (AMPK) activation, but it has been identified in the other studies that AMPK is not the sole hub in metformin mode of action or there are other unknown mechanisms which are involved and yet to be explored. Therefore, here, we discuss the updated findings of the mechanism of action of metformin that contributes to the meta-inflammation and inflammaging action. It is proposed that figuring out the precise mechanism of action of metformin could improve its application in the fields of obesity, inflammation, aging, and inflammaging.
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Affiliation(s)
- Meysam Khodadadi
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Davoud Jafari-Gharabaghlou
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Clinical Biochemistry and Laboratory Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Nosratollah Zarghami
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran. .,Department of Medical Biochemistry, Faculty of Medicine, Istanbul Aydin University, Istanbul, Turkey. .,Department of Clinical Biochemistry and Laboratory Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
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4
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Interaction Profiles of Central Nervous System Active Drugs at Human Organic Cation Transporters 1-3 and Human Plasma Membrane Monoamine Transporter. Int J Mol Sci 2021; 22:ijms222312995. [PMID: 34884800 PMCID: PMC8657792 DOI: 10.3390/ijms222312995] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/26/2021] [Accepted: 11/28/2021] [Indexed: 12/31/2022] Open
Abstract
Many psychoactive compounds have been shown to primarily interact with high-affinity and low-capacity solute carrier 6 (SLC6) monoamine transporters for norepinephrine (NET; norepinephrine transporter), dopamine (DAT; dopamine transporter) and serotonin (SERT; serotonin transporter). Previous studies indicate an overlap between the inhibitory capacities of substances at SLC6 and SLC22 human organic cation transporters (SLC22A1-3; hOCT1-3) and the human plasma membrane monoamine transporter (SLC29A4; hPMAT), which can be classified as high-capacity, low-affinity monoamine transporters. However, interactions between central nervous system active substances, the OCTs, and the functionally-related PMAT have largely been understudied. Herein, we report data from 17 psychoactive substances interacting with the SLC6 monoamine transporters, concerning their potential to interact with the human OCT isoforms and hPMAT by utilizing radiotracer-based in vitro uptake inhibition assays at stably expressing human embryonic kidney 293 cells (HEK293) cells. Many compounds inhibit substrate uptake by hOCT1 and hOCT2 in the low micromolar range, whereas only a few substances interact with hOCT3 and hPMAT. Interestingly, methylphenidate and ketamine selectively interact with hOCT1 or hOCT2, respectively. Additionally, 3,4-methylenedioxymethamphetamine (MDMA) is a potent inhibitor of hOCT1 and 2 and hPMAT. Enantiospecific differences of R- and S-α-pyrrolidinovalerophenone (R- and S-α-PVP) and R- and S-citalopram and the effects of aromatic substituents are explored. Our results highlight the significance of investigating drug interactions with hOCTs and hPMAT, due to their role in regulating monoamine concentrations and xenobiotic clearance.
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5
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Miller SR, Jilek JL, McGrath ME, Hau RK, Jennings EQ, Galligan JJ, Wright SH, Cherrington NJ. Testicular disposition of clofarabine in rats is dependent on equilibrative nucleoside transporters. Pharmacol Res Perspect 2021; 9:e00831. [PMID: 34288585 PMCID: PMC8292784 DOI: 10.1002/prp2.831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 06/18/2021] [Indexed: 01/13/2023] Open
Abstract
Acute lymphoblastic leukemia (ALL) is the most common cancer in children and adolescents. Although the 5-year survival rate is high, some patients respond poorly to chemotherapy or have recurrence in locations such as the testis. The blood-testis barrier (BTB) can prevent complete eradication by limiting chemotherapeutic access and lead to testicular relapse unless a chemotherapeutic is a substrate of drug transporters present at this barrier. Equilibrative nucleoside transporter (ENT) 1 and ENT2 facilitate the movement of substrates across the BTB. Clofarabine is a nucleoside analog used to treat relapsed or refractory ALL. This study investigated the role of ENTs in the testicular disposition of clofarabine. Pharmacological inhibition of the ENTs by 6-nitrobenzylthioinosine (NBMPR) was used to determine ENT contribution to clofarabine transport in primary rat Sertoli cells, in human Sertoli cells, and across the rat BTB. The presence of NBMPR decreased clofarabine uptake by 40% in primary rat Sertoli cells (p = .0329) and by 53% in a human Sertoli cell line (p = .0899). Rats treated with 10 mg/kg intraperitoneal (IP) injection of the NBMPR prodrug, 6-nitrobenzylthioinosine 5'-monophosphate (NBMPR-P), or vehicle, followed by an intravenous (IV) bolus 10 mg/kg dose of clofarabine, showed a trend toward a lower testis concentration of clofarabine than vehicle (1.81 ± 0.59 vs. 2.65 ± 0.92 ng/mg tissue; p = .1160). This suggests that ENTs could be important for clofarabine disposition. Clofarabine may be capable of crossing the human BTB, and its potential use as a first-line treatment to avoid testicular relapse should be considered.
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Affiliation(s)
- Siennah R. Miller
- College of PharmacyDepartment of Pharmacology & ToxicologyUniversity of ArizonaTucsonAZUSA
| | - Joseph L. Jilek
- College of PharmacyDepartment of Pharmacology & ToxicologyUniversity of ArizonaTucsonAZUSA
| | - Meghan E. McGrath
- College of PharmacyDepartment of Pharmacology & ToxicologyUniversity of ArizonaTucsonAZUSA
| | - Raymond K. Hau
- College of PharmacyDepartment of Pharmacology & ToxicologyUniversity of ArizonaTucsonAZUSA
| | - Erin Q. Jennings
- College of PharmacyDepartment of Pharmacology & ToxicologyUniversity of ArizonaTucsonAZUSA
| | - James J. Galligan
- College of PharmacyDepartment of Pharmacology & ToxicologyUniversity of ArizonaTucsonAZUSA
| | - Stephen H. Wright
- College of MedicineDepartment of PhysiologyUniversity of ArizonaTucsonAZUSA
| | - Nathan J. Cherrington
- College of PharmacyDepartment of Pharmacology & ToxicologyUniversity of ArizonaTucsonAZUSA
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6
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Römer S, Meyer MJ, Klein K, Schneider LV, Matthaei J, Tzvetkova A, Łapczuk-Romańska J, Gaedcke J, Droździk M, Brockmöller J, Nies AT, Tzvetkov MV. Effects of a Common Eight Base Pairs Duplication at the Exon 7-Intron 7 Junction on Splicing, Expression, and Function of OCT1. Front Pharmacol 2021; 12:661480. [PMID: 34025422 PMCID: PMC8137991 DOI: 10.3389/fphar.2021.661480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/14/2021] [Indexed: 11/13/2022] Open
Abstract
Organic cation transporter 1 (OCT1, SLC22A1) is localized in the sinusoidal membrane of human hepatocytes and mediates hepatic uptake of weakly basic or cationic drugs and endogenous compounds. Common amino acid substitutions in OCT1 were associated with altered pharmacokinetics and efficacy of drugs like sumatriptan and fenoterol. Recently, the common splice variant rs35854239 has also been suggested to affect OCT1 function. rs35854239 represents an 8 bp duplication of the donor splice site at the exon 7-intron 7 junction. Here we quantified the extent to which this duplication affects OCT1 splicing and, as a consequence, the expression and the function of OCT1. We used pyrosequencing and deep RNA-sequencing to quantify the effect of rs35854239 on splicing after minigene expression of this variant in HepG2 and Huh7 cells and directly in human liver samples. Further, we analyzed the effects of rs35854239 on OCT1 mRNA expression in total, localization and activity of the resulting OCT1 protein, and on the pharmacokinetics of sumatriptan and fenoterol. The 8 bp duplication caused alternative splicing in 38% (deep RNA-sequencing) to 52% (pyrosequencing) of the minigene transcripts when analyzed in HepG2 and Huh7 cells. The alternatively spliced transcript encodes for a truncated protein that after transient transfection in HEK293 cells was not localized in the plasma membrane and was not able to transport the OCT1 model substrate ASP+. In human liver, however, the alternatively spliced OCT1 transcript was detectable only at very low levels (0.3% in heterozygous and 0.6% in homozygous carriers of the 8 bp duplication, deep RNA-sequencing). The 8 bp duplication was associated with a significant reduction of OCT1 expression in the human liver, but explained only 9% of the general variability in OCT1 expression and was not associated with significant changes in the pharmacokinetics of sumatriptan and fenoterol. Therefore, the rs35854239 variant only partially changes splicing, causing moderate changes in OCT1 expression and may be of only limited therapeutic relevance.
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Affiliation(s)
- Sarah Römer
- Institute of Pharmacology, Center of Drug Absorption and Transport (C_DAT), University Medicine Greifswald, Greifswald, Germany
| | - Marleen J Meyer
- Institute of Pharmacology, Center of Drug Absorption and Transport (C_DAT), University Medicine Greifswald, Greifswald, Germany
| | - Kathrin Klein
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany.,University of Tuebingen, Tuebingen, Germany
| | - Lennart V Schneider
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Göttingen, Germany
| | - Johannes Matthaei
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Göttingen, Germany
| | - Ana Tzvetkova
- Institute of Bioinformatics, University Medicine Greifswald, Greifswald, Germany.,Human Molecular Genetics Group, Department of Functional Genomics, Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Joanna Łapczuk-Romańska
- Department of Experimental and Clinical Pharmacology, Pomeranian Medical University, Szczecin, Poland
| | - Jochen Gaedcke
- Department of General, Visceral and Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Marek Droździk
- Department of Experimental and Clinical Pharmacology, Pomeranian Medical University, Szczecin, Poland
| | - Jürgen Brockmöller
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Göttingen, Germany
| | - Anne T Nies
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany.,University of Tuebingen, Tuebingen, Germany.,Cluster of Excellence iFIT (EXC2180) "Image-Guided and Functionally Instructed Tumor Therapies", University of Tuebingen, Tuebingen, Germany
| | - Mladen V Tzvetkov
- Institute of Pharmacology, Center of Drug Absorption and Transport (C_DAT), University Medicine Greifswald, Greifswald, Germany
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7
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Haberkorn B, Fromm MF, König J. Transport of Drugs and Endogenous Compounds Mediated by Human OCT1: Studies in Single- and Double-Transfected Cell Models. Front Pharmacol 2021; 12:662535. [PMID: 33967805 PMCID: PMC8100673 DOI: 10.3389/fphar.2021.662535] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/19/2021] [Indexed: 12/11/2022] Open
Abstract
Organic Cation Transporter 1 (OCT1, gene symbol: SLC22A1) is predominately expressed in human liver, localized in the basolateral membrane of hepatocytes and facilitates the uptake of endogenous compounds (e.g. serotonin, acetylcholine, thiamine), and widely prescribed drugs (e.g. metformin, fenoterol, morphine). Furthermore, exogenous compounds such as MPP+, ASP+ and Tetraethylammonium can be used as prototypic substrates to study the OCT1-mediated transport in vitro. Single-transfected cell lines recombinantly overexpressing OCT1 (e.g., HEK-OCT1) were established to study OCT1-mediated uptake and to evaluate transporter-mediated drug-drug interactions in vitro. Furthermore, double-transfected cell models simultaneously overexpressing basolaterally localized OCT1 together with an apically localized export protein have been established. Most of these cell models are based on polarized grown MDCK cells and can be used to analyze transcellular transport, mimicking the transport processes e.g. during the hepatobiliary elimination of drugs. Multidrug and toxin extrusion protein 1 (MATE1, gene symbol: SLC47A1) and the ATP-driven efflux pump P-glycoprotein (P-gp, gene symbol: ABCB1) are both expressed in the canalicular membrane of human hepatocytes and are described as transporters of organic cations. OCT1 and MATE1 have an overlapping substrate spectrum, indicating an important interplay of both transport proteins during the hepatobiliary elimination of drugs. Due to the important role of OCT1 for the transport of endogenous compounds and drugs, in vitro cell systems are important for the determination of the substrate spectrum of OCT1, the understanding of the molecular mechanisms of polarized transport, and the investigation of potential drug-drug interactions. Therefore, the aim of this review article is to summarize the current knowledge on cell systems recombinantly overexpressing human OCT1.
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Affiliation(s)
- Bastian Haberkorn
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Martin F Fromm
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Jörg König
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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8
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Zhou S, Zeng S, Shu Y. Drug-Drug Interactions at Organic Cation Transporter 1. Front Pharmacol 2021; 12:628705. [PMID: 33679412 PMCID: PMC7925875 DOI: 10.3389/fphar.2021.628705] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/13/2021] [Indexed: 12/19/2022] Open
Abstract
The interaction between drugs and various transporters is one of the decisive factors that affect the pharmacokinetics and pharmacodynamics of drugs. The organic cation transporter 1 (OCT1) is a member of the Solute Carrier 22A (SLC22A) family that plays a vital role in the membrane transport of organic cations including endogenous substances and xenobiotics. This article mainly discusses the drug-drug interactions (DDIs) mediated by OCT1 and their clinical significance.
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Affiliation(s)
- Shiwei Zhou
- Key Laboratory of Oral Medicine, School and Hospital of Stomatology, Guangzhou Medical University, Guangzhou, China.,Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, Baltimore, MD, United States.,Department of Thyroid Surgery, The Second Xiangya Hospital, Central South University, Hunan, China
| | - Sujuan Zeng
- Key Laboratory of Oral Medicine, School and Hospital of Stomatology, Guangzhou Medical University, Guangzhou, China
| | - Yan Shu
- Key Laboratory of Oral Medicine, School and Hospital of Stomatology, Guangzhou Medical University, Guangzhou, China.,Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, Baltimore, MD, United States
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9
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Cabral LKD, Tiribelli C, Sukowati CHC. Sorafenib Resistance in Hepatocellular Carcinoma: The Relevance of Genetic Heterogeneity. Cancers (Basel) 2020; 12:E1576. [PMID: 32549224 PMCID: PMC7352671 DOI: 10.3390/cancers12061576] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 02/06/2023] Open
Abstract
Despite advances in biomedicine, the incidence and the mortality of hepatocellular carcinoma (HCC) remain high. The majority of HCC cases are diagnosed in later stages leading to the less than optimal outcome of the treatments. Molecular targeted therapy with sorafenib, a dual-target inhibitor targeting the serine-threonine kinase Raf and the tyrosine kinases VEGFR/PDGFR, is at present the main treatment for advanced-stage HCC, either in a single or combinatory regimen. However, it was observed in a large number of patients that its effectiveness is hampered by drug resistance. HCC is highly heterogeneous, within the tumor and among individuals, and this influences disease progression, classification, prognosis, and naturally cellular susceptibility to drug resistance. This review aims to provide an insight on how HCC heterogeneity influences the different primary mechanisms of chemoresistance against sorafenib including reduced drug intake, enhanced drug efflux, intracellular drug metabolism, alteration of molecular targets, activation/inactivation of signaling pathways, changes in the DNA repair machinery, and negative balance between apoptosis and survival of the cancer cells. The diverse variants, mutations, and polymorphisms in molecules and their association with drug response can be a helpful tool in treatment decision making. Accordingly, the existence of heterogeneous biomarkers in the tumor must be considered to strengthen multi-target strategies in patient-tailored treatment.
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Affiliation(s)
| | | | - Caecilia H. C. Sukowati
- Fondazione Italiana Fegato (Italian Liver Foundation), AREA Science Park, Basovizza, 34149 Trieste, Italy; (L.K.D.C.); (C.T.)
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10
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Brosseau N, Ramotar D. The human organic cation transporter OCT1 and its role as a target for drug responses. Drug Metab Rev 2019; 51:389-407. [PMID: 31564168 DOI: 10.1080/03602532.2019.1670204] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The human organic cation uptake transporter OCT1, encoded by the SLC22A1 gene, is highly expressed in the liver and reported to possess a broad substrate specificity. OCT1 operates by facilitated diffusion and allows the entry of nutrients into cells. Recent findings revealed that OCT1 can mediate the uptake of drugs for treating various diseases such as cancers. The levels of OCT1 expression correlate with the responses towards many drugs and functionally defective OCT1 lead to drug resistance. It has been recently proposed that OCT1 should be amongst the crucial drug targets used for pharmacogenomic analyses. Several single nucleotide polymorphisms exist and are distributed across the entire OCT1 gene. While there are differences in the OCT1 gene polymorphisms between populations, there are at least five variants that warrant consideration in any genetic screen. To date, and despite two decades of research into OCT1 functional role, it still remains uncertain what are the define substrates for this uptake transporter, although studies from mice revealed that one of the substrates is vitamin B1. It is also unclear how OCT1 recognizes a broad array of ligands and whether this involves specific modifications and interactions with other proteins. In this review, we highlight the current findings related to OCT1 with the aim of propelling further studies on this key uptake transporter.
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Affiliation(s)
- Nicolas Brosseau
- Department of Medicine, Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal, Montréal, Québec, Canada
| | - Dindial Ramotar
- Department of Medicine, Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal, Montréal, Québec, Canada
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11
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Roner MR, Carraher CE, Miller L, Mosca F, Slawek P, Haky JE, Frank J. Organotin Polymers as Antiviral Agents Including Inhibition of Zika and Vaccinia Viruses. J Inorg Organomet Polym Mater 2019. [DOI: 10.1007/s10904-019-01250-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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12
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Mallayasamy S, Penzak SR. Pharmacogenomic Considerations in the Treatment of HIV Infection. Pharmacogenomics 2019. [DOI: 10.1016/b978-0-12-812626-4.00008-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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13
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Bokelmann K, Brockmöller J, Tzvetkov MV. Impact of Promoter Polymorphisms on the Transcriptional Regulation of the Organic Cation Transporter OCT1 (SLC22A1). J Pers Med 2018; 8:jpm8040042. [PMID: 30544975 PMCID: PMC6313513 DOI: 10.3390/jpm8040042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/20/2018] [Accepted: 12/05/2018] [Indexed: 01/12/2023] Open
Abstract
The organic cation transporter 1 (OCT1, SLC22A1) is strongly expressed in the human liver and facilitates the hepatic uptake of drugs such as morphine, metformin, tropisetron, sumatriptan and fenoterol and of endogenous substances such as thiamine. OCT1 expression is inter-individually highly variable. Here, we analyzed SNPs in the OCT1 promoter concerning their potential contribution to the variability in OCT1 expression. Using electrophoretic mobility shift and luciferase reporter gene assays in HepG2, Hep3B, and Huh7 cell lines, we identified the SNPs −1795G>A (rs6935207) and −201C>G (rs58812592) as having effects on transcription factor binding and/or promoter activity. The A-allele of the −1795G>A SNP showed allele-specific binding of the transcription factor NF-Y leading to 2.5-fold increased enhancer activity of the artificial SV40 promoter. However, the −1795G>A SNP showed no significant effects on the native OCT1 promoter activity. Furthermore, the −1795G>A SNP was not associated with the pharmacokinetics of metformin, fenoterol, sumatriptan and proguanil in healthy individuals or tropisetron efficacy in patients undergoing chemotherapy. Allele-dependent differences in USF1/2 binding and nearly total loss in OCT1 promoter activity were detected for the G-allele of −201C>G, but the SNP is apparently very rare. In conclusion, common OCT1 promoter SNPs have only minor effects on OCT1 expression.
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Affiliation(s)
- Kristin Bokelmann
- Institute of Clinical Pharmacology, University Medical Center, Georg-August-University, 37075 Göttingen, Germany.
| | - Jürgen Brockmöller
- Institute of Clinical Pharmacology, University Medical Center, Georg-August-University, 37075 Göttingen, Germany.
| | - Mladen V Tzvetkov
- Institute of Pharmacology, Center of Drug Absorption and Transport (C_DAT), University Medicine Greifswald, 17487 Greifswald, Germany.
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14
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Shen H, Li W, Humphreys WG, Lai Y. Tenofovir Disoproxil Fumarate Is Not an Inhibitor of Human Organic Cation Transporter 1. J Pharmacol Exp Ther 2018; 360:341-342. [PMID: 28104831 DOI: 10.1124/jpet.116.238337] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Affiliation(s)
- Hong Shen
- Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Company, Princeton, New Jersey
| | - Wenying Li
- Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Company, Princeton, New Jersey
| | - W Griffith Humphreys
- Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Company, Princeton, New Jersey
| | - Yurong Lai
- Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Company, Princeton, New Jersey
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15
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Boxberger KH, Hagenbuch B, Lampe JN. Ligand-dependent modulation of hOCT1 transport reveals discrete ligand binding sites within the substrate translocation channel. Biochem Pharmacol 2018; 156:371-384. [PMID: 30138624 PMCID: PMC6195816 DOI: 10.1016/j.bcp.2018.08.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/17/2018] [Indexed: 12/18/2022]
Abstract
The human hepatic organic cation transporter 1 (hOCT1) is a well-known transporter of both xenobiotic and endogenous cations. The substrates and inhibitors of hOCT1 are structurally and physiochemically diverse and include some widely prescribed drugs (metformin and imatinib), vitamins (thiamine), and neurotransmitters (serotonin). It has been demonstrated that the closely related renal isoform, hOCT2, is subject to ligand-dependent modulation, wherein one ligand may enhance or inhibit transport of a second, chemically unrelated, ligand. This phenomenon has important implications for drug-drug interactions due to the ubiquity of polypharmacy and the large number of drugs that are present as cations under physiological conditions. Therefore, the objective of this study was to determine if hOCT1 is subject to the same ligand-dependent modulation as hOCT2, and to identify unique putative ligand binding sites in the translocation channel for a sub-set of ligands using computational modeling. The competitive counter flow (CCF) assay was employed to examine ligand-dependent effects by utilizing four different radiolabeled probe substrates: MPP+, serotonin, metformin, and TEA. We identified 20 ligands that modulated the transport of the four test substrates examined. One of the putative ligands identified, BSP, is an anion at physiological pH. Direct uptake studies of radiolabeled BSP suggested that it is a hOCT1 substrate with a Km of 13.6 ± 2.6 µM and Vmax of 55.1 ± 4.1 pmol/mg protein/min. Each ligand identified was computationally docked into a homology model of hOCT1 using the UCSF DOCK software package. The docking study revealed three separate ligand binding pockets within the hOCT1 translocation pathway, defined by their interactions with three prototypical substrates: MPP+, TEA, and acyclovir. Our results suggest that hOCT1 is not only subject to ligand-dependent modulation, but also that individual ligand binding occurs at discrete sites within the hOCT1 translocation pathway which may influence ligand binding at the other sites.
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Affiliation(s)
- Kelli H Boxberger
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Bruno Hagenbuch
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States; The University of Kansas Cancer Center, Kansas City, KS 66160, United States; The University of Kansas Liver Center, Kansas City, KS 66160, United States
| | - Jed N Lampe
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States; The University of Kansas Liver Center, Kansas City, KS 66160, United States.
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