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Ohura K, Nakada Y, Imai T. Bioconversion and P-gp-Mediated Transport of Depot Fluphenazine Prodrugs after Intramuscular Injection. J Pharm Sci 2023; 112:1975-1984. [PMID: 37019360 DOI: 10.1016/j.xphs.2023.03.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/26/2023] [Accepted: 03/26/2023] [Indexed: 04/07/2023]
Abstract
Fluphenazine (FPZ) decanoate, an ester-type prodrug formulated as a long-acting injection (LAI), is used in the treatment of schizophrenia. FPZ enanthate was also developed as an LAI formulation, but is no longer in use clinically because of the short elimination half-life of FPZ, the parent drug, after intramuscular injection. In the present study, the hydrolysis of FPZ prodrugs was evaluated in human plasma and liver to clarify the reason for this difference in elimination half-lives. FPZ prodrugs were hydrolyzed in human plasma and liver microsomes. The rate of hydrolysis of FPZ enanthate in human plasma and liver microsomes was 15-fold and 6-fold, respectively, faster than that of FPZ decanoate. Butyrylcholinesterase (BChE) and human serum albumin (HSA) present in human plasma, and two carboxylesterase (CES) isozymes, hCE1 and hCE2, expressed in ubiquitous organs including liver, were mainly responsible for the hydrolysis of FPZ prodrugs. FPZ prodrugs may not be bioconverted in human skeletal muscle at the injection site because of lack of expression of BChE and CESs in muscle. Interestingly, although FPZ was a poor substrate for human P-glycoprotein, FPZ caproate was a good substrate. In conclusion, it is suggested that the shorter elimination half-life of FPZ following administration of FPZ enanthate compared with FPZ decanoate can be attributed to the more rapid hydrolysis of FPZ enanthate by BChE, HSA and CESs.
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Affiliation(s)
- Kayoko Ohura
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan; Headquarters for Admissions and Education, Kumamoto University, Kumamoto, Japan
| | | | - Teruko Imai
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan; Daiichi University of Pharmacy, Fukuoka, Japan.
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Imai S, Ichikawa T, Sugiyama C, Nonaka K, Yamada T. Contribution of Human Liver and Intestinal Carboxylesterases to the Hydrolysis of Selexipag In Vitro. J Pharm Sci 2018; 108:1027-1034. [PMID: 30267780 DOI: 10.1016/j.xphs.2018.09.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 09/07/2018] [Accepted: 09/14/2018] [Indexed: 02/01/2023]
Abstract
In liver microsomes, selexipag (NS-304; ACT-293987) mainly undergoes hydrolytic removal of the sulfonamide moiety by carboxylesterase 1 (CES1) to yield the pharmacologically active metabolite MRE-269 (ACT-333679). However, it is not known how much CES in the liver and intestine contributes to the hydrolysis of selexipag or how selexipag is metabolized in the intestine, including by hydrolysis. To obtain a better understanding of selexipag metabolism in humans, we determined the percentage contribution of CES1 and carboxylesterase 2 (CES2) to the hydrolysis of selexipag and 7 of its analogs with different sulfonamide moieties and evaluated its nonhydrolytic metabolism in human liver microsomes and human intestinal microsomes (HIMS). For selexipag, the percentage contributions of CES1 and CES2 in human liver microsomes were 77.0% and 9.99%, respectively, while the percentage contribution of CES2 in HIMS was 100%. In HIMS, the rate of hydrolysis of selexipag was the lowest among the compounds tested, and no difference between the presence and absence of nicotinamide adenine dinucleotide phosphate was noted. We infer from these results that selexipag is likely to be hydrolyzed by CES2 as well as CES1, and only selexipag itself and the MRE-269 produced by hydrolysis in the intestine would be absorbed after oral administration.
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Affiliation(s)
- Shunji Imai
- Pharmacokinetics and Safety Assessment Department, Discovery Research Laboratories, Nippon Shinyaku Co., Ltd, Kyoto, Japan.
| | - Tomohiko Ichikawa
- Pharmacokinetics and Safety Assessment Department, Discovery Research Laboratories, Nippon Shinyaku Co., Ltd, Kyoto, Japan
| | - Chihiro Sugiyama
- Pharmacokinetics and Safety Assessment Department, Discovery Research Laboratories, Nippon Shinyaku Co., Ltd, Kyoto, Japan
| | - Kiyoko Nonaka
- Pharmacokinetics and Safety Assessment Department, Discovery Research Laboratories, Nippon Shinyaku Co., Ltd, Kyoto, Japan
| | - Tetsuhiro Yamada
- Pharmacokinetics and Safety Assessment Department, Discovery Research Laboratories, Nippon Shinyaku Co., Ltd, Kyoto, Japan
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Ishizaki Y, Furihata T, Oyama Y, Ohura K, Imai T, Hosokawa M, Akita H, Chiba K. Development of a Caco-2 Cell Line Carrying the Human Intestine-Type CES Expression Profile as a Promising Tool for Ester-Containing Drug Permeability Studies. Biol Pharm Bull 2018; 41:697-706. [DOI: 10.1248/bpb.b17-00880] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yuma Ishizaki
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University
| | - Tomomi Furihata
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University
- Department of Pharmacology, Graduate School of Medicine, Chiba University
| | - Yusuke Oyama
- Department of Metabolism-Based Drug Design and Delivery, Graduate School of Pharmaceutical Science, Kumamoto University
| | - Kayoko Ohura
- Department of Metabolism-Based Drug Design and Delivery, Graduate School of Pharmaceutical Science, Kumamoto University
| | - Teruko Imai
- Department of Metabolism-Based Drug Design and Delivery, Graduate School of Pharmaceutical Science, Kumamoto University
| | - Masakiyo Hosokawa
- Laboratory of Drug Metabolism and Biopharmaceutics, Faculty of Pharmaceutical Sciences, Chiba Institute of Science
| | - Hidetaka Akita
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University
| | - Kan Chiba
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University
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Ito M, Kusuhara H, Ose A, Kondo T, Tanabe K, Nakayama H, Horita S, Fujita T, Sugiyama Y. Pharmacokinetic Modeling and Monte Carlo Simulation to Predict Interindividual Variability in Human Exposure to Oseltamivir and Its Active Metabolite, Ro 64-0802. AAPS J 2017; 19:286-297. [PMID: 27800573 DOI: 10.1208/s12248-016-9992-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 08/31/2016] [Indexed: 12/14/2022] Open
Abstract
Oseltamivir (Tamiflu®) is a prodrug of Ro 64-0802, a selective inhibitor of influenza virus neuraminidase. There is a possible relationship between oseltamivir treatment and neuropsychiatric adverse events; although this has not been established, close monitoring is recommended on the prescription label. The objective of this study was to predict interindividual variability of human exposure to oseltamivir and its active metabolite Ro 64-0802. By leveraging mathematical models and computations, physiological parameters in virtual subjects were generated with population means and coefficient of variations collected from the literature or produced experimentally. Postulated functional changes caused by genetic mutations in four key molecules, carboxylesterase 1A1, P-glycoprotein, organic anion transporter 3, and multidrug resistance-associated protein 4, were also taken into account. One hundred thousand virtual subjects were generated per simulation, which was iterated 20 times with different random number generator seeds. Even in the most exaggerated case, the systemic areas under the concentration-time curve (AUCs) of oseltamivir and Ro 64-0802 were increased by at most threefold compared with the population mean. By contrast, the brain AUCs of oseltamivir and Ro 64-0802 were increased up to about sevenfold and 40-fold, respectively, compared with the population means. This unexpectedly high exposure to oseltamivir or Ro 64-0802, which occurs extremely rarely, might trigger adverse central nervous system effects in the clinical setting.
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Affiliation(s)
- Mototsugu Ito
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroyuki Kusuhara
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Atsushi Ose
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Tsunenori Kondo
- Department of Urology, Tokyo Women's Medical University, Tokyo, Japan
| | - Kazunari Tanabe
- Department of Urology, Tokyo Women's Medical University, Tokyo, Japan
| | - Hideki Nakayama
- Department of Urology, Tokyo Women's Medical University, Tokyo, Japan
| | - Shigeru Horita
- Department of Urology, Tokyo Women's Medical University, Tokyo, Japan
| | - Takuya Fujita
- College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Yuichi Sugiyama
- Sugiyama Laboratory, RIKEN Innovation Center, Research Cluster for Innovation, RIKEN, Kanagawa, Japan.
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Wang H, Rangan VS, Sung MC, Passmore D, Kempe T, Wang X, Thevanayagam L, Pan C, Rao C, Srinivasan M, Zhang Q, Gangwar S, Deshpande S, Cardarelli P, Marathe P, Yang Z. Pharmacokinetic characterization of BMS-936561, an anti-CD70 antibody-drug conjugate, in preclinical animal species and prediction of its pharmacokinetics in humans. Biopharm Drug Dispos 2015; 37:93-106. [PMID: 25869904 DOI: 10.1002/bdd.1953] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 03/11/2015] [Accepted: 03/31/2015] [Indexed: 11/11/2022]
Abstract
CD70 is a tumor necrosis factor (TNF)-like type II integral membrane protein that is transiently expressed on activated T- and B-lymphocytes. Aberrant expression of CD70 was identified in both solid tumors and haematologic malignancies. BMS-936561 (αCD70_MED-A) is an antibody-drug conjugate composed of a fully human anti-CD70 monoclonal antibody (αCD70) conjugated with a duocarmycin derivative, MED-A, through a maleimide-containing citrulline-valine dipeptide linker. MED-A is a carbamate prodrug that is activated by carboxylesterase to its active form, MED-B, to exert its DNA alkylation activity. In vitro serum stability studies suggested the efficiencies of hydrolyzing the carbamate-protecting group in αCD70_MED-A followed a rank order of mouse>rat > >monkey>dog~human. Pharmacokinetics of αCD70_MED-A was evaluated in mice, monkeys, and dogs after single intravenous doses. In mice, αCD70_MED-A was cleared rapidly, with no detectable exposures after 15 min following dosing. In contrast, αCD70_MED-A was much more stable in monkeys and dogs. The clearance of αCD70_MED-A in monkeys was 58 mL/d/kg, ~2-fold faster than that in dogs (31 mL/d/kg). The human PK profiles of the total αCD70 and αCD70_MED-A were predicted using allometrically scaled monkeys PK parameters of αCD70 and the carbamate hydrolysis rate constant estimated in dogs. Comparing the predicted and observed human PK from the phase I study, the dose-normalized concentration-time profiles of αCD70_MED-A and the total αCD70 were largely within the 5(th)-95(th) percentile of the predicted profiles.
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Affiliation(s)
- Haiqing Wang
- Metabolism and Pharmacokinetics, Bristol-Myers Squibb, Princeton, NJ, United States
| | - Vangipuram S Rangan
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - Mei-Chen Sung
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - David Passmore
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - Thomas Kempe
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - Xiaoli Wang
- Clinical Pharmacology, Bristol-Myers Squibb, Princeton, NJ, United States
| | - Lourdes Thevanayagam
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - Chin Pan
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - Chetana Rao
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - Mohan Srinivasan
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - Qian Zhang
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - Sanjeev Gangwar
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - Shrikant Deshpande
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - Pina Cardarelli
- Biologics Discovery California, Bristol-Myers Squibb, Redwood City, CA, United States
| | - Punit Marathe
- Metabolism and Pharmacokinetics, Bristol-Myers Squibb, Princeton, NJ, United States
| | - Zheng Yang
- Metabolism and Pharmacokinetics, Bristol-Myers Squibb, Princeton, NJ, United States
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Seki C, Oh-Nishi A, Nagai Y, Minamimoto T, Obayashi S, Higuchi M, Takei M, Furutsuka K, Ito T, Zhang MR, Ito H, Ito M, Ito S, Kusuhara H, Sugiyama Y, Suhara T. Evaluation of [(11)C]oseltamivir uptake into the brain during immune activation by systemic polyinosine-polycytidylic acid injection: a quantitative PET study using juvenile monkey models of viral infection. EJNMMI Res 2014; 4:24. [PMID: 25045603 PMCID: PMC4100568 DOI: 10.1186/s13550-014-0024-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 04/21/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Abnormal behaviors of young patients after taking the anti-influenza agent oseltamivir (Tamiflu®, F. Hoffmann-La Roche, Ltd., Basel, Switzerland) have been suspected as neuropsychiatric adverse events (NPAEs). Immune response to viral infection is suspected to cause elevation of drug concentration in the brain of adolescents. In the present study, the effect of innate immune activation on the brain uptake of [(11)C]oseltamivir was quantitatively evaluated in juvenile monkeys. METHODS Three 2-year-old monkeys underwent positron emission tomography (PET) scans at baseline and immune-activated conditions. Both scans were conducted under pre-dosing of clinically relevant oseltamivir. The immune activation condition was induced by the intravenous administration of polyinosine-polycytidylic acid (poly I:C). Dynamic [(11)C]oseltamivir PET scan and serial arterial blood sampling were performed to obtain [(11)C]oseltamivir kinetics. Brain uptake of [(11)C]oseltamivr was evaluated by its normalized brain concentration, brain-to-plasma concentration ratio, and plasma-to-brain transfer rate. Plasma pro-inflammatory cytokine levels were also measured. RESULTS Plasma interleukin-6 was elevated after intravenous administration of poly I:C in all monkeys. Brain radioactivity was uniform both at baseline and under poly I:C treatment. The mean brain concentrations of [(11)C]oseltamivir were 0.0033 and 0.0035% ID/cm(3) × kg, the mean brain-to-plasma concentration ratios were 0.58 and 0.65, and the plasma-to-brain transfer rates were 0.0047 and 0.0051 mL/min/cm(3) for baseline and poly I:C treatment, respectively. Although these parameters were slightly changed by immune activation, the change was not notable. CONCLUSIONS The brain uptake of [(11)C]oseltamivir was unchanged by poly I:C treatment in juvenile monkeys. This study demonstrated that the innate immune response similar to the immune activation of influenza would not notably change the brain concentration of oseltamivir in juvenile monkeys.
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Affiliation(s)
- Chie Seki
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
| | - Arata Oh-Nishi
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
| | - Yuji Nagai
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
| | - Takafumi Minamimoto
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
| | - Shigeru Obayashi
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
| | - Makoto Higuchi
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
| | - Makoto Takei
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
| | - Kenji Furutsuka
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
| | - Takehito Ito
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
| | - Ming-Rong Zhang
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
| | - Hiroshi Ito
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
| | - Mototsugu Ito
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku 133-0033, Tokyo, Japan
| | - Sumito Ito
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku 133-0033, Tokyo, Japan
| | - Hiroyuki Kusuhara
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku 133-0033, Tokyo, Japan
| | - Yuichi Sugiyama
- Sugiyama Laboratory, RIKEN Innovation Center, Research Cluster for Innovation, RIKEN, 1-6, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Kanagawa, Japan
| | - Tetsuya Suhara
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku 265-8555, Chiba, Japan
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Ono H, Iwajima Y, Nagano Y, Chazono K, Maeda Y, Ohsawa M, Yamamoto S. Reduction in sympathetic nerve activity as a possible mechanism for the hypothermic effect of oseltamivir, an anti-influenza virus drug, in normal mice. Basic Clin Pharmacol Toxicol 2013; 113:25-30. [PMID: 23398656 DOI: 10.1111/bcpt.12058] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 01/31/2013] [Indexed: 11/28/2022]
Abstract
Oseltamivir, an anti-influenza virus drug, has strong antipyretic effects in mice (Biological and Pharmaceutical Bulletin, 31, 2008, 638) and patients with influenza. In addition, hypothermia has been reported as an adverse event. The prodrug oseltamivir is converted to oseltamivir carboxylate (OC), an active metabolite of influenza virus neuraminidase. In this study, core body temperature was measured in mice, and oseltamivir and OC were administered intracerebroventricularly (i.c.v.) or intraperitoneally (i.p). Low i.c.v. doses of oseltamivir and OC dose-dependently produced hypothermia. Zanamivir (i.c.v.), another neuraminidase inhibitor, did not produce hypothermia. These results suggested that the hypothermic effects of oseltamivir (i.p. and i.c.v.) and OC (i.c.v.) are not due to neuraminidase inhibition. OC (i.p.) did not lower body temperature. Although mecamylamine (i.c.v.) blocked the hypothermic effect of nicotine-administered i.c.v., the hypothermic effects of oseltamivir and OC (i.c.v.) were not blocked by mecamylamine (i.c.v.). The effect of oseltamivir (i.p.) was markedly increased by s.c.-pre-administered mecamylamine and also hexamethonium, a peripherally acting ganglionic blocker, suggesting their potentiating interaction at peripheral sites. The hypothermic effect of nicotine (i.c.v.) was decreased by lower doses of oseltamivir (i.c.v.), suggesting the anti-nicotinic action of oseltamivir. These results suggest that oseltamivir (i.p.) causes hypothermia through depression of sympathetic temperature regulatory mechanisms via inhibition of nicotinic receptor function and through unknown central mechanisms.
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Affiliation(s)
- Hideki Ono
- Laboratory of CNS Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan.
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Crielaard BJ, van der Wal S, Lammers T, Le HT, Hennink WE, Schiffelers RM, Storm G, Fens MH. A polymeric colchicinoid prodrug with reduced toxicity and improved efficacy for vascular disruption in cancer therapy. Int J Nanomedicine 2011; 6:2697-703. [PMID: 22114500 PMCID: PMC3218583 DOI: 10.2147/ijn.s24450] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Colchicinoids are very potent tubulin-binding compounds, which interfere with microtubule formation, giving them strong cytotoxic properties, such as cell mitosis inhibition and induction of microcytoskeleton depolymerization. While this makes them promising vascular disrupting agents (VDAs) in cancer therapy, their dose-limiting toxicity has prevented any clinical application for this purpose. Therefore, colchicinoids are considered attractive lead molecules for the development of novel vascular disrupting nanomedicine. In a previous study, a polymeric colchicinoid prodrug that showed favorable hydrolysis characteristics at physiological conditions was developed. In the current study, this polymeric colchicinoid prodrug was evaluated in vitro and in vivo for its toxicity and vascular disrupting potential. Cell viability studies with human umbilical vein endothelial cells, as an in vitro measure for colchicine activity, reflected the degradation kinetics of the prodrug accordingly. Upon intravenous treatment, in vivo, of B16F10 melanoma-bearing mice with colchicine or with the polymeric colchicinoid prodrug, apparent vascular disruption and consequent tumor necrosis was observed for the prodrug but not for free colchicine at an equivalent dose. Moreover, a five-times-higher dose of the prodrug was well tolerated, indicating reduced toxicity. These findings demonstrate that the polymeric colchicinoid prodrug has a substantially improved efficacy/toxicity ratio compared with that of colchicine, making it a promising VDA for cancer therapy.
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Affiliation(s)
- Bart J Crielaard
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
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Ohtsuki S, Uchida Y, Kubo Y, Terasaki T. Quantitative targeted absolute proteomics-based ADME research as a new path to drug discovery and development: methodology, advantages, strategy, and prospects. J Pharm Sci 2011; 100:3547-59. [PMID: 21560129 DOI: 10.1002/jps.22612] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 04/18/2011] [Accepted: 04/20/2011] [Indexed: 11/08/2022]
Abstract
An understanding of the functional roles of proteins, for example, in drug absorption, distribution, metabolism, elimination, toxicity, and efficacy (ADMET/efficacy), is important for drug discovery and development. Equally, detailed information about protein expression is required. Recently, a new protein quantification method, called quantitative targeted absolute proteomics (QTAP), has been developed on the basis of separation and identification of protein digests by liquid chromatography-linked tandem mass spectrometry with multiple reaction monitoring. Target peptides for quantification are selected only from sequence information, so time-consuming procedures such as antibody preparation and protein purification are unnecessary. In this review, we introduce the technical features of QTAP and summarize its advantages with reference to recently reported results. These include the evaluation of species differences of blood-brain barrier protein levels among human, monkey, and mouse. The high selectivity of QTAP and its ability to quantify multiple proteins simultaneously make it possible to determine the absolute expression levels of many proteins in tissues and cells in both physiological and disease states. Knowledge of absolute expression amounts, together with data on intrinsic protein activity, allows us to reconstruct in vivo protein function, and this should be an efficient strategy to predict ADMET/efficacy of drug candidates in humans in various disease states.
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Affiliation(s)
- Sumio Ohtsuki
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
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Affiliation(s)
| | - Masaki Igarashi
- University of Tokyo Tokyo, Japan (Igarashi, Sekiya, Okazaki)
| | - Motohiro Sekiya
- University of Tokyo Tokyo, Japan (Igarashi, Sekiya, Okazaki)
| | - Hiroaki Okazaki
- University of Tokyo Tokyo, Japan (Igarashi, Sekiya, Okazaki)
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Dickinson PJ, LeCouteur RA, Higgins RJ, Bringas JR, Larson RF, Yamashita Y, Krauze MT, Forsayeth J, Noble CO, Drummond DC, Kirpotin DB, Park JW, Berger MS, Bankiewicz KS. Canine spontaneous glioma: a translational model system for convection-enhanced delivery. Neuro Oncol 2010; 12:928-40. [PMID: 20488958 DOI: 10.1093/neuonc/noq046] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Canine spontaneous intracranial tumors bear striking similarities to their human tumor counterparts and have the potential to provide a large animal model system for more realistic validation of novel therapies typically developed in small rodent models. We used spontaneously occurring canine gliomas to investigate the use of convection-enhanced delivery (CED) of liposomal nanoparticles, containing topoisomerase inhibitor CPT-11. To facilitate visualization of intratumoral infusions by real-time magnetic resonance imaging (MRI), we included identically formulated liposomes loaded with Gadoteridol. Real-time MRI defined distribution of infusate within both tumor and normal brain tissues. The most important limiting factor for volume of distribution within tumor tissue was the leakage of infusate into ventricular or subarachnoid spaces. Decreased tumor volume, tumor necrosis, and modulation of tumor phenotype correlated with volume of distribution of infusate (Vd), infusion location, and leakage as determined by real-time MRI and histopathology. This study demonstrates the potential for canine spontaneous gliomas as a model system for the validation and development of novel therapeutic strategies for human brain tumors. Data obtained from infusions monitored in real time in a large, spontaneous tumor may provide information, allowing more accurate prediction and optimization of infusion parameters. Variability in Vd between tumors strongly suggests that real-time imaging should be an essential component of CED therapeutic trials to allow minimization of inappropriate infusions and accurate assessment of clinical outcomes.
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Affiliation(s)
- Peter J Dickinson
- Department of Surgical and Radiological of Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California 95616-8745, USA.
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Hwang HJ, Kim SW, Baek YM, Lee SH, Hwang HS, Yun JW. Gene expression profiling in streptozotocin-induced diabetic rat liver in response to fungal polysaccharide treatment. KOREAN J CHEM ENG 2009; 26:115-26. [DOI: 10.1007/s11814-009-0018-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Ose A, Ito M, Kusuhara H, Yamatsugu K, Kanai M, Shibasaki M, Hosokawa M, Schuetz JD, Sugiyama Y. Limited brain distribution of [3R,4R,5S]-4-acetamido-5-amino-3-(1-ethylpropoxy)-1-cyclohexene-1-carboxylate phosphate (Ro 64-0802), a pharmacologically active form of oseltamivir, by active efflux across the blood-brain barrier mediated by organic anion transporter 3 (Oat3/Slc22a8) and multidrug resistance-associated protein 4 (Mrp4/Abcc4). Drug Metab Dispos 2008; 37:315-21. [PMID: 19029202 DOI: 10.1124/dmd.108.024018] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
[3R,4R,5S]-4-Acetamido-5-amino-3-(1-ethylpropoxy)-1-cyclohexene-1-carboxylate phosphate (Ro 64-0802) is a pharmacologically active form of the anti-influenza virus drug oseltamivir. Abnormal behavior is a suspected adverse effect of oseltamivir on the central nervous system. This study focused on the transport mechanisms of Ro 64-0802 across the blood-brain barrier (BBB). Ro 64-0802 was found to be a substrate of organic anion transporter 3 (OAT3/SLC22A8) and multidrug resistance-associated protein 4 (MRP4/ABCC4). Human embryonic kidney 293 cells expressing OAT3 exhibited a greater intracellular accumulation of Ro 64-0802 than mock-transfected cells (15 versus 1.2 microl/mg protein/10 min, respectively). The efflux of Ro 64-0802 was 3-fold greater when MRP4 was expressed in MDCKII cells and was significantly inhibited by indomethacin. After its microinjection into the cerebrum, the amount of Ro 64-0802 in brain was significantly greater in both Oat3(-/-) mice and Mrp4(-/-) mice compared with the corresponding wild-type mice (0.36 versus 0.080 and 0.32 versus 0.060 nmol at 120 min after injection, respectively). The brain/plasma concentration ratio (K(p,) (brain)) of Ro 64-0802, determined in wild-type mice after subcutaneous continuous infusion for 24 h, was close to the capillary volume (approximately 10 microl/g brain). Although the K(p,) (brain) of Ro 64-0802 was unchanged in Oat3(-/-) mice, it was significantly greater in Mrp4(-/-) mice (41 microl/g of brain). These results suggest that Ro 64-0802 can cross the BBB from the blood, but its brain distribution is limited by its active efflux by Mrp4 and Oat3 across the BBB. The transporter responsible for the brain uptake of Ro 64-0802 remains unknown, but Oat3 is a candidate transporter.
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Affiliation(s)
- Atsushi Ose
- Department of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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14
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Xu Z, Zhou X, Lu H, Wu N, Zhao H, Zhang L, Zhang W, Liang YL, Wang L, Liu Y, Yang P, Zha X. Comparative glycoproteomics based on lectins affinity capture of N-linked glycoproteins from human Chang liver cells and MHCC97-H cells. Proteomics 2007; 7:2358-70. [PMID: 17623300 DOI: 10.1002/pmic.200600041] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We present here an effective technique for the large-scale separation and identification of N-linked glycoproteins from Chang liver cells, the human normal liver cells. To enrich N-linked glycoproteins from the whole cells, a procedure containing the lysis of human liver cells, the solubilization of total proteins, lectin affinity chromatography including Concanavalin A and wheat germ agglutinin was established. Furthermore, captured N-linked glycoproteins were separated by 2-DE, and identified by MS and database searching. Finally, we found 63 N-glycoproteins in Chang liver cells. In addition, using the above method, we identified 7 remarkably up-regulated glycoproteins from MHCC97-H cells, highly metastatic liver cancer cells, compared to Chang liver cells. These up-regulated glycoproteins were associated with liver cancer and might be used as biomarkers for tumor diagnosis. Results showed that we established a high-throughput proteomic analysis for separating N-linked glycoproteins from human liver cells. This strategy greatly improved the glycoprotein analysis method associated with proteome-wide glycosylation changes related to liver cancer. Our work was part of the HUPO Human Liver Proteome Project (HLPP) studies and was supported by CHINA HUPO.
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Affiliation(s)
- Zhibin Xu
- Glycoconjugate Key Laboratory, Ministry of Health, Department of Biochemistry and Molecular Biology, Fudan University, Shanghai, PR China
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15
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Imai T, Taketani M, Shii M, Hosokawa M, Chiba K. Substrate specificity of carboxylesterase isozymes and their contribution to hydrolase activity in human liver and small intestine. Drug Metab Dispos 2006; 34:1734-41. [PMID: 16837570 DOI: 10.1124/dmd.106.009381] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hydrolase activity from human liver and small intestine microsomes was compared with that of recombinant human carboxylesterases, hCE-1 and hCE-2. Although both hCE-1 and hCE-2 are present in human liver, the dominant component was found to be hCE-1, whereas the hydrolase activity of the human small intestine was found to be predominantly hCE-2. hCE-2 has a limited ability to hydrolyze large acyl compound substrates. Interestingly, propranolol derivatives, good substrates for hCE-2, were easily hydrolyzed by substitution of the methyl group on the 2-position of the acyl moiety, but were barely hydrolyzed when the methyl group was substituted on the 3-position. These findings suggest that hCE-2 does not easily form acylated intermediates because of conformational interference in its active site. In contrast, hCE-1 could hydrolyze a variety of substrates. The hydrolytic activity of hCE-2 increased with increasing alcohol chain length in benzoic acid derivative substrates, whereas hCE-1 preferentially catalyzed the hydrolysis of substrates with short alcohol chains. Kinetic data showed that the determining factor for the rate of hydrolysis of p-aminobenzoic acid esters was V(max) for hCE-1 and K(m) for hCE-2. Furthermore, the addition of hydrophobic alcohols to the reaction mixture with p-aminobenzoic acid propyl ester induced high and low levels of transesterification by hCE-1 and hCE-2, respectively. When considering the substrate specificities of hCE-1, it is necessary to consider the transesterification ability of hCE-1, in addition to the binding structure of the substrate in the active site of the enzyme.
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Affiliation(s)
- Teruko Imai
- Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Kumamoto 862-0973, Japan.
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16
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Satoh T, Hosokawa M. Structure, function and regulation of carboxylesterases. Chem Biol Interact 2006; 162:195-211. [PMID: 16919614 DOI: 10.1016/j.cbi.2006.07.001] [Citation(s) in RCA: 354] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 06/14/2006] [Accepted: 07/01/2006] [Indexed: 11/22/2022]
Abstract
This review covers current developments in molecular-based studies of the structure and function of carboxylesterases. To allay the confusion of the classic classification of carboxylesterase isozymes, we have proposed a novel nomenclature and classification of mammalian carboxylesterases on the basis of molecular properties. In addition, mechanisms of regulation of gene expression of carboxylesterases by xenobiotics and involvement of carboxylesterase in drug metabolism and enzyme induction are also described.
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Affiliation(s)
- Tetsuo Satoh
- Graduate School of Pharmaceutical Sciences, Chiba University, Japan.
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17
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Tabata T, Katoh M, Tokudome S, Nakajima M, Yokoi T. Identification of the cytosolic carboxylesterase catalyzing the 5'-deoxy-5-fluorocytidine formation from capecitabine in human liver. Drug Metab Dispos 2004; 32:1103-10. [PMID: 15269188 DOI: 10.1124/dmd.104.000554] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Capecitabine, a prodrug of 5-fluorouracil, is first metabolized to 5'-deoxy-5-fluorocytidine (5'-DFCR) by carboxylesterase (CES), which is mainly expressed in microsomes. Recently, we clarified that 5'-DFCR formation was catalyzed by the enzyme in cytosol as well as microsomes in human liver. In the present study, the cytosolic enzyme involved in 5'-DFCR formation from capecitabine was identified. This enzyme was purified in the cytosolic preparation by ammonium sulfate precipitation, Sephacryl S-300 gel filtration, Mono P chromatofocusing, and Superdex 200 gel filtration. The purified enzyme was identified by the amino acid sequence analysis to be CES1A1 or a CES1A1 precursor. Based on the result of the N-terminal amino acid sequence analysis, the purified enzyme has no putative signal peptide, indicating that it was CES1A1. The apparent Km and Vmax values of 5'-DFCR formation were 19.2 mM and 88.3 nmol/min/mg protein, respectively. The 5'-DFCR formation catalyzed by the purified enzyme was inhibited by both diisopropylfluorophosphate and bis(p-nitrophenyl)phosphate in a concentration-dependent manner. 7-Ethyl-10-hydroxycamptothecin (SN-38) formation from irinotecan also occurred in the purified enzyme, cytosol, and microsomes. In conclusion, the cytosolic enzyme involved in 5'-DFCR formation from capecitabine would be CES1A1. It is suggested that the cytosolic CES has significant hydrolysis activity and plays an important role as the microsomal CES in drug metabolism. It is worthy to investigate the metabolic enzyme in cytosol involved in the activation of ester-type prodrugs such as capecitabine.
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Affiliation(s)
- Toshiki Tabata
- Drug Metabolism and Toxicology, Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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18
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Abstract
Carboxylesterases play an important role in the hydrolytic biotransformation of a number of structurally diverse endogenous compounds and medications. Several distinct carboxylesterase isoforms have been described in human liver, brain, and placenta. Carboxylesterase-2 has been identified as the key enzyme in the metabolic activation of the irinotecan, a topoisomerase I inhibitor commonly used in the treatment of many solid tumors. The tissue distribution and intensity of protein expression of carboxylesterase-2 have not been defined in any organ or tissue. This study used a carboxylesterase-2-specific antibody and tissue array analysis to detect carboxylesterase-2 expression in human normal tissues by immunohistochemistry. Carboxylesterase-2 is present in a wide variety of organs and tissues. The highest carboxylesterase-2 expression occurs in hepatocyte, small intestine mucosa, kidney proximal convoluted tubule, and adrenal cortex cells. The results suggest that liver and gastrointestinal tract with carboxylesterase-2 are likely the most important sites of conversion of irinotecan to the active metabolite SN-38, but carboxylesterase-2 within the other tissues may be contributive to this process. In the central nervous system, carboxylesterase-2 expression was confined to capillary endothelial cells, consistent with the enzyme having a role to protect the central nervous system from toxic esters and perhaps being a component of a blood-brain barrier system.
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Affiliation(s)
- Wanghai Zhang
- Washington University School of Medicine, Department of Medicine, Siteman Cancer Center, St. Louis, Missouri 63110, USA
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19
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Abstract
This article reports on a symposium sponsored by the American Society for Pharmacology and Experimental Therapeutics and held at the April 2001 Experimental Biology meeting. Current developments in molecular-based studies into the structure and function of cholinesterases, carboxylesterases, and paraoxonases are described. This article covers mechanisms of regulation of gene expression of the various esterases by developmental factors and xenobiotics, as well as the interplay between physiological and chemical regulation of enzyme activity.
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Affiliation(s)
- Tetsuo Satoh
- Biomedical Research Institute, Chiba University, Chiba, Japan
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Xie M, Yang D, Liu L, Xue B, Yan B. Human and rodent carboxylesterases: immunorelatedness, overlapping substrate specificity, differential sensitivity to serine enzyme inhibitors, and tumor-related expression. Drug Metab Dispos 2002; 30:541-7. [PMID: 11950785 DOI: 10.1124/dmd.30.5.541] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Carboxylesterases hydrolyze numerous endogenous and foreign compounds with diverse structures. Humans and rodents express multiple forms of carboxylesterases, which share a high degree of sequence identity (approximately 70%). Alignment analyses locate in carboxylesterases several functional subsites such the catalytic triad as seen in acetylcholinesterase. The aim of this study was to determine among human and rodent carboxylesterases the immunorelatedness, overlapping substrate specificity, differential sensitivity to serine enzyme inhibitors, tissue distribution, and tumor-related expression. Six antibodies against whole carboxylesterases or synthetic peptides were tested for their reactivity toward 11 human or rodent recombinant carboxylesterases. The antibodies against whole proteins generally exhibited a broader cross-reactivity than the anti-peptide antibodies. All carboxylesterases hydrolyzed para-nitrophenylacetate and para-nitrophenylbutyrate. However, the relative activity varied markedly from enzyme to enzyme (>20-fold), and some carboxylesterases showed a clear substrate preference. Carboxylesterases with the same functional subsites had a similar profile on substrate specificity and sensitivity toward phenylmethylsulfonyl fluoride (PMSF) and paraoxon, suggesting that these subsites play determinant roles in the recognition of substrates and inhibitors. Among three human carboxylesterases, HCE-1 hydrolyzed both substrates to a similar extent, whereas HCE-2 and HCE-3 showed an opposite substrate preference. All three enzymes were inhibited by PMSF and paraoxon, but they showed a marked difference in relative sensitivities. Based on immunoblotting analyses, HCE-1 was present in all tissues examined, whereas HCE-2 and HCE-3 were expressed in a tissue-restricted pattern. Colon carcinomas expressed slightly higher levels of HCE-1 and HCE-2 than the adjacent normal tissues, whereas the opposite was true with HCE-3.
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Affiliation(s)
- Mingxing Xie
- Department of Biomedical Sciences, University of Rhode Island, Kingston, Rhode Island 02881, USA
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21
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Abstract
Organophosphorus esters have the potential to produce several forms of toxicity. Most produce acute intoxication as a result of inhibition of acetylcholinesterase and, if severe, this can have longer lasting secondary consequences such as intermediate syndrome, or even permanent disability. Some esters produce a very specific syndrome of delayed peripheral neuropathy. This neuropathy is always preceded by severe acute intoxication, except in the case of a few specific agents such as tri-o-cresyl phosphate. All of these effects are reasonably well understood and show a dose threshold. Chronic low level exposure in non-poisoned subjects has been associated with impaired neurobehavioral performance in some, but not all, epidemiological studies. The mechanisms involved are not well understood, but if organophosphates do play a causal role, this will not necessarily be via acetylcholinesterase inhibition. Doses too low to produce cholinergic signs have been shown to produce a variety of effects in experimental animals ranging from enhanced maze learning to slowed nerve conduction. It is likely that other, more sensitive, brain proteins are the targets for such actions. Effects mediated via such target proteins would be expected to show very different structure-activity relationships to acute toxicity mediated by acetylcholinesterase. Hence epidemiological studies expecting similar (class) effects from low-dose exposure to different organophosphorus esters may produce variable results or false negatives.
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Affiliation(s)
- D E Ray
- Medical Research Council Toxicology Unit, Hodgkin Building, Lancaster Road, LE1 9HN, Leicester, UK.
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Affiliation(s)
- A C Sehgal
- Department of Chemical Engineering, North Carolina State University, Raleigh, North Carolina 27606, USA
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24
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Scott DF, Chacko TL, Maxwell DM, Schlager JJ, Lanclos KD. Expression and partial purification of a recombinant secretory form of human liver carboxylesterase. Protein Expr Purif 1999; 17:16-25. [PMID: 10497064 DOI: 10.1006/prep.1999.1121] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Serine-dependent carboxylesterases (EC 3.1.1.1) are found in a variety of tissues with high activity detected in the liver. Carboxylesterases (CaE) hydrolyze aliphatic and aromatic esters, and aromatic amides, and play an important role in the detoxification of xenobiotic chemicals that contain organophosphate (OP) compounds. The detoxifying ability of CaE is limited by its low concentration in serum where it encounters OP compounds. Studies in our laboratory have shown that a pRC/CMV-hCaE plasmid construct, stably integrated into 293T cells, expresses a human liver CaE in culture. However, the enzyme remained inside the cell and reached a low steady-state level of expression. The goals of this study were to overexpress a functional human liver CaE from a recombinant cDNA in a human cell line and to isolate and purify the recombinant protein. To accomplish these goals, a single amino acid change was made in the C-terminal retrieval signal, HIEL (His-Ile-Glu-Leu), of human liver CaE. The mutation produced a unique Eco47III restriction site, which aided in clone selection. The recombinant plasmid, pRc/CMV-mhCaE, was isolated and stably integrated into human 293T cells. Expression of the altered cDNA resulted in secretion of an active CaE up to levels of 500 enzyme units per liter of growth medium. Secretory CaE displayed isoelectric focusing patterns similar to those of the native enzyme with no observable changes in activity. The secreted enzyme was partially purified by hydrophobic interaction chromatography and Cibacron blue affinity chromatography. Partial enzyme purification was achieved, and CaE retained a high level of enzymatic activity.
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Affiliation(s)
- D F Scott
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia 30912, USA
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25
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Abstract
The DNA sequence encoding a novel human brain carboxylesterase (CES) has been determined. The protein is predicted to have 567 amino acids, including conserved motifs, such as GESAGG, GXXXXEFG, and GDHGD which comprise a catalytic triad, and the endoplasmic reticulum retention motif (HXEL-COOH) observed in CES families. Their gene products exhibited hydrolase activity towards temocapril, p-nitrophenyl-acetate and long-chain acyl-CoA. Since the molecular masses of these gene products are similar to those that exist in capillary endothelial cells of the human brain [Yamamda et al. (1994) Brain Res. 658, 163-167], these CES isozymes may function as a blood-brain barrier to protect the central nervous system from ester or amide compounds.
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Affiliation(s)
- M Mori
- Laboratory of Biochemical Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, Chiba University, Japan
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26
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Abstract
Multiple carboxylesterases (EC 3.1.1.1) play an important role in the hydrolytic biotransformation of a vast number of structurally diverse drugs. These enzymes are major determinants of the pharmacokinetic behavior of most therapeutic agents containing ester or amide bonds. Carboxylesterase activity can be influenced by interactions of a variety of compounds either directly or at the level of enzyme regulation. Since a significant number of drugs are metabolized by carboxylesterase, altering the activity of this enzyme class has important clinical implications. Drug elimination decreases and the incidence of drug-drug interactions increases when two or more drugs compete for hydrolysis by the same carboxylesterase isozyme. Exposure to environmental pollutants or to lipophilic drugs can result in induction of carboxylesterase activity. Therefore, the use of drugs known to increase the microsomal expression of a particular carboxylesterase, and thus to increase associated drug hydrolysis capacity in humans, requires caution. Mammalian carboxylesterases represent a multigene family, the products of which are localized in the endoplasmic reticulum of many tissues. A comparison of the nucleotide and amino acid sequence of the mammalian carboxylesterases shows that all forms expressed in the rat can be assigned to one of three gene subfamilies with structural identities of more than 70% within each subfamily. Considerable confusion exists in the scientific community in regards to a systematic nomenclature and classification of mammalian carboxylesterase. Until recently, adequate sequence information has not been available such that valid links among the mammalian carboxylesterase gene family or evolutionary relationships could be established. However, sufficient basic data are now available to support such a novel classification system.
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Affiliation(s)
- T Satoh
- Laboratory of Biochemical Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, Chiba University, Japan.
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