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Baum M, Dobler S. Fecal Deployment: An Alternative Way of Defensive Host Plant Cardenolide Use by Lilioceris merdigera Larvae. J Chem Ecol 2024; 50:63-70. [PMID: 38062246 PMCID: PMC10991028 DOI: 10.1007/s10886-023-01465-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/26/2023] [Accepted: 11/28/2023] [Indexed: 04/04/2024]
Abstract
The brilliant red Lilioceris merdigera (Coleoptera, Chrysomelidae) can spend its entire life cycle on the cardenolide-containing plant Convallaria majalis (lily of the valley) and forms stable populations on this host. Yet, in contrast to many other insects on cardenolide-containing plants L. merdigera does not sequester these plant toxins in the body but rather both adult beetles and larvae eliminate ingested cardenolides with the feces. Tracer feeding experiments showed that this holds true for radioactively labeled ouabain and digoxin, a highly polar and a rather apolar cardenolide. Both compounds or their derivatives are incorporated in the fecal shields of the larvae. The apolar digoxin, but not the polar ouabain, showed a deterrent effect on the generalist predatory ant Myrmica rubra, which occurs in the habitat of L. merdigera. The deterrent effect was detected for digoxin both in choice and feeding time assays. In a predator choice assay, a fecal shield derived from a diet of cardenolide-containing C. majalis offered L. merdigera larvae better protection from M. rubra than one derived from non-cardenolide Allium schoenoprasum (chives) or no fecal shield at all. Thus, we here present data suggesting a new way how insects may gain protection by feeding on cardenolide-containing plants.
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Affiliation(s)
- Michael Baum
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany.
- Chemistry Education Department, IPN, Leibniz Institute for Science and Mathematics Education, Olshausenstraße 62, 24118, Kiel, Germany.
| | - Susanne Dobler
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany
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2
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Li M, Xu W, Zhang L, Gao E, Han X, Chen Z. Convallatoxin Inhibits Cell Proliferation and Induces Cell Apoptosis by Attenuating the Akt-E2F1 Signaling Pathway in K562 Cells. Nat Prod Commun 2022. [DOI: 10.1177/1934578x221136929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective: To determine the effect of convallatoxin on K562 cell proliferation and apoptosis. Methods: CCK-8 assay was used to detect cell proliferation; PI staining, JC-1 staining, and Annexin V-FITC/PI double staining were used to analyze the cell cycle, cell mitochondrial membrane potential, and cell apoptosis; and Western blotting was used to detect cleaved caspase-9, cleaved caspase-3, Bcl-2, Bax, and E2F1 expression and Akt phosphorylation. Subsequently, AutoDock software was used to determine the interaction between convallatoxin and Akt1. Results: Upon treatment with convallatoxin, the proliferation of K562 cells was inhibited, the cells were arrested at the S and G2/M phases, and cell apoptosis was significantly induced. In addition, Akt phosphorylation and E2F1 expression were significantly decreased, whereas E2F1 overexpression rescued convallatoxin-induced cell proliferation and apoptosis. In addition, a molecular docking assay indicated that convallatoxin could bind to Akt1. Conclusion: Convallatoxin inhibited cell proliferation and induced mitochondrial-related apoptosis in K562 cells by reducing the Akt-E2F1 signaling pathway, indicating that it is a potential agent for treating leukemia.
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Affiliation(s)
- Man Li
- Department of Clinical Laboratory, The Second People's Hospital of Hefei, Hefei, China
| | - Wangwang Xu
- Anhui Province Key Laboratory of Translational Cancer Research, Bengbu Medical College, Bengbu, China
| | - Lu Zhang
- Anhui Province Key Laboratory of Translational Cancer Research, Bengbu Medical College, Bengbu, China
| | - Erke Gao
- Anhui Province Key Laboratory of Translational Cancer Research, Bengbu Medical College, Bengbu, China
| | - Xiaojin Han
- Anhui Province Key Laboratory of Translational Cancer Research, Bengbu Medical College, Bengbu, China
| | - Zhengxu Chen
- Department of Clinical Laboratory, The Second People's Hospital of Hefei, Hefei, China
- Anhui Province Key Laboratory of Translational Cancer Research, Bengbu Medical College, Bengbu, China
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3
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Yin J, Li X, Li F, Lu Y, Zeng S, Zhu F. Identification of the key target profiles underlying the drugs of narrow therapeutic index for treating cancer and cardiovascular disease. Comput Struct Biotechnol J 2021; 19:2318-2328. [PMID: 33995923 PMCID: PMC8105181 DOI: 10.1016/j.csbj.2021.04.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/09/2021] [Accepted: 04/15/2021] [Indexed: 12/14/2022] Open
Abstract
An appropriate therapeutic index is crucial for drug discovery and development since narrow therapeutic index (NTI) drugs with slight dosage variation may induce severe adverse drug reactions or potential treatment failure. To date, the shared characteristics underlying the targets of NTI drugs have been explored by several studies, which have been applied to identify potential drug targets. However, the association between the drug therapeutic index and the related disease has not been dissected, which is important for revealing the NTI drug mechanism and optimizing drug design. Therefore, in this study, two classes of disease (cancers and cardiovascular disorders) with the largest number of NTI drugs were selected, and the target property of the corresponding NTI drugs was analyzed. By calculating the biological system profiles and human protein–protein interaction (PPI) network properties of drug targets and adopting an AI-based algorithm, differentiated features between two diseases were discovered to reveal the distinct underlying mechanisms of NTI drugs in different diseases. Consequently, ten shared features and four unique features were identified for both diseases to distinguish NTI from NNTI drug targets. These computational discoveries, as well as the newly found features, suggest that in the clinical study of avoiding narrow therapeutic index in those diseases, the ability of target to be a hub and the efficiency of target signaling in the human PPI network should be considered, and it could thus provide novel guidance in the drug discovery and clinical research process and help to estimate the drug safety of cancer and cardiovascular disease.
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Affiliation(s)
- Jiayi Yin
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xiaoxu Li
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Fengcheng Li
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yinjing Lu
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Su Zeng
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China.,Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, Hangzhou 310018, China
| | - Feng Zhu
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China.,Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, Hangzhou 310018, China.,Alibaba-Zhejiang University Joint Research Center of Future Digital Healthcare, Hangzhou 330110, China
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4
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Malysheva SV, Mulder PPJ, Masquelier J. Development and Validation of a UHPLC-ESI-MS/MS Method for Quantification of Oleandrin and Other Cardiac Glycosides and Evaluation of Their Levels in Herbs and Spices from the Belgian Market. Toxins (Basel) 2020; 12:E243. [PMID: 32283845 PMCID: PMC7232191 DOI: 10.3390/toxins12040243] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/04/2020] [Accepted: 04/08/2020] [Indexed: 01/02/2023] Open
Abstract
Cardiac glycosides (CGs) are naturally occurring plant secondary metabolites that can be toxic to humans and animals. The aim of this work was to develop a targeted analytical method utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS) for quantification of these plant toxins in a herbal-based food and human urine. The method included oleandrin, digoxin, digitoxin, convallatoxin, and ouabain. Samples of culinary herbs were extracted with acetonitrile and cleaned using Oasis® MAX solid-phase extraction (SPE), while samples of urine were diluted with acidified water and purified on Oasis® HLB SPE cartridges. Limits of quantification were in the range of 1.5-15 ng/g for herbs and 0.025-1 ng/mL for urine. The mean recovery of the method complied with the acceptable range of 70-120% for most CGs, and relative standard deviations were at maximum 14% and 19% for repeatability and reproducibility, respectively. Method linearity was good with calculated R² values above 0.997. The expanded measurement uncertainty was estimated to be in the range of 7-37%. The LC-MS/MS method was used to examine 65 samples of culinary herbs and herb and spice mixtures collected in Belgium, from supermarkets and local stores. The samples were found to be free from the analyzed CGs.
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Affiliation(s)
| | - Patrick P. J. Mulder
- Wageningen Food Safety Research, Wageningen University and Research, 6708 WB Wageningen, The Netherlands;
| | - Julien Masquelier
- Unit Toxins, Organic Contaminants and Additives, Sciensano, 1050 Brussels, Belgium;
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5
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Chao PK, Chang HF, Ou LC, Chuang JY, Lee PT, Chang WT, Chen SC, Ueng SH, Hsu JTA, Tao PL, Law PY, Loh HH, Yeh SH. Convallatoxin enhance the ligand-induced mu-opioid receptor endocytosis and attenuate morphine antinociceptive tolerance in mice. Sci Rep 2019; 9:2405. [PMID: 30787373 PMCID: PMC6382827 DOI: 10.1038/s41598-019-39555-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 01/07/2019] [Indexed: 11/29/2022] Open
Abstract
Morphine is a unique opioid analgesic that activates the mu-opioid receptor (MOR) without efficiently promoting its endocytosis that may underlie side effects. Our objective was to discover a novel enhancer of ligand-induced MOR endocytosis and determine its effects on analgesia, tolerance and dependence. We used high-throughput screening to identify convallatoxin as an enhancer of ligand-induced MOR endocytosis with high potency and efficacy. Treatment of cells with convallatoxin enhanced morphine-induced MOR endocytosis through an adaptor protein 2 (AP2)/clathrin-dependent mechanism, attenuated morphine-induced phosphorylation of MOR, and diminished desensitization of membrane hyperpolarization. Furthermore, co-treatment with chronic convallatoxin reduced morphine tolerance in animal models of acute thermal pain and chronic inflammatory pain. Acute convallatoxin administration reversed morphine tolerance and dependence in morphine-tolerant mice. These findings suggest convallatoxin are potentially therapeutic for morphine side effects and open a new avenue to study MOR trafficking.
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Affiliation(s)
- Po-Kuan Chao
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Hsiao-Fu Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Li-Chin Ou
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Jian-Ying Chuang
- The PhD Program for Neural Regenerative Medicine, Taipei Medical University, Taipei, 110, Taiwan
| | - Pin-Tse Lee
- Cellular Pathobiology Section, Intramural Research Program, National Institute on Drug Abuse, NIH/DHHS, Baltimore, MD, 21224, USA
| | - Wan-Ting Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Shu-Chun Chen
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Shau-Hua Ueng
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - John Tsu-An Hsu
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Pao-Luh Tao
- Center for Neuropsychiatric Research, National Heath Research Institutes, Zhunan, 35053, Taiwan
| | - Ping-Yee Law
- Department of Pharmacology, Medical School University of Minnesota, Minneapolis, MN, 55455-0217, USA
| | - Horace H Loh
- Department of Pharmacology, Medical School University of Minnesota, Minneapolis, MN, 55455-0217, USA
| | - Shiu-Hwa Yeh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan.
- The PhD Program for Neural Regenerative Medicine, Taipei Medical University, Taipei, 110, Taiwan.
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6
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Therapeutic Potential and Utility of Elacridar with Respect to P-glycoprotein Inhibition: An Insight from the Published In Vitro, Preclinical and Clinical Studies. Eur J Drug Metab Pharmacokinet 2018; 42:915-933. [PMID: 28374336 DOI: 10.1007/s13318-017-0411-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The occurrence of efflux mechanisms via Permeability-glycoprotein (P-gp) recognized as an important physiological process impedes drug entry or transport across membranes into tissues. In some instances, either low oral bioavailability or lack of brain penetration has been attributed to P-gp mediated efflux activity. Therefore, the objective of development of P-gp inhibitors was to facilitate the attainment of higher drug exposures in tissues. Many third-generation P-gp inhibitors such as elacridar, tariquidar, zosuquidar, etc. have entered clinical development to fulfil the promise. The body of evidence from in vitro and in vivo preclinical and clinical data reviewed in this paper provides the basis for an effective blockade of P-gp efflux mechanism by elacridar. However, clinical translation of the promise has been elusive not just for elacridar but also for other P-gp inhibitors in this class. The review provides introspection and perspectives on the lack of clinical translation of this class of drugs and a broad framework of strategies and considerations in the potential application of elacridar and other P-gp inhibitors in oncology therapeutics.
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7
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Eliesen GAM, van den Broek P, van den Heuvel JJ, Bilos A, Pertijs J, van Drongelen J, Russel FGM, Greupink R. Editor's Highlight: PlacentalDisposition and Effects of Crizotinib: An Ex Vivo Study in the Isolated Dual-Side Perfused Human Cotyledon. Toxicol Sci 2018; 157:500-509. [PMID: 28369651 DOI: 10.1093/toxsci/kfx063] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Tyrosine kinase inhibitors (TKIs) play an important role in cancer pharmacotherapy, yet there is limited data on their use during pregnancy. We studied placental disposition and placental toxicity of crizotinib, a TKI used to treat nonsmall cell lung cancer. Term placentas were perfused for 3 h with crizotinib (1 µM) using the ex vivo dual-side cotyledon perfusion technique. Interference of TKIs with trophoblast viability was studied using BeWo cells. Expression of P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP) in placental tissue was assessed by immunohistochemistry and inhibition of these transporters was determined in vitro by transport studies with membrane vesicles overexpressing human P-gp or BCRP. We found that crizotinib rapidly and strongly accumulates in cotyledon perfusion experiments, reaching a concentration of 3.1 ± 0.4 µM in placental tissue. Final drug concentrations in the maternal and foetal reservoirs were 0.2 ± 0.05 and 0.08 ± 0.01 µM, respectively. Furthermore, crizotinib inhibited BeWo cell viability (IC50: 234 nM, 95% CI: 167-328 nM) 10 times more potently than other TKIs tested. In vitro transport studies revealed that crizotinib is a potent inhibitor of the transport activities of BCRP (IC50: 5.7 µM, 95% CI: 2.7-11.8 µM) and P-gp (IC50: 7.8 µM, 95% CI: 3.4-18.0 µM). In conclusion, crizotinib strongly accumulated in placental tissue at clinically relevant concentrations. IC50 values for transporter inhibition and trophoblast cell viability were similar to the tissue concentrations reached, suggesting that crizotinib can inhibit placental BCRP and P-gp function and possibly affect trophoblast viability.
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Affiliation(s)
- Gaby A M Eliesen
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Petra van den Broek
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Jeroen J van den Heuvel
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Albert Bilos
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Jeanne Pertijs
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Joris van Drongelen
- Department of Obstetrics and Gynecology, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frans G M Russel
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Rick Greupink
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
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8
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Inhibitory Potential of Antifungal Drugs on ATP-Binding Cassette Transporters P-Glycoprotein, MRP1 to MRP5, BCRP, and BSEP. Antimicrob Agents Chemother 2016; 60:3372-9. [PMID: 27001813 DOI: 10.1128/aac.02931-15] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/10/2016] [Indexed: 12/21/2022] Open
Abstract
Inhibition of ABC transporters is a common mechanism underlying drug-drug interactions (DDIs). We determined the inhibitory potential of antifungal drugs currently used for invasive fungal infections on ABC transporters P-glycoprotein (P-gp), MRP1 to MRP5, BCRP, and BSEP in vitro Membrane vesicles isolated from transporter-overexpressing HEK 293 cells were used to investigate the inhibitory potential of antifungal drugs (250 μM) on transport of model substrates. Concentration-inhibition curves were determined if transport inhibition was >60%. Fifty percent inhibitory concentrations (IC50s) for P-gp and BCRP were both 2 μM for itraconazole, 5 and 12 μM for hydroxyitraconazole, 3 and 6 μM for posaconazole, and 3 and 11 μM for isavuconazole, respectively. BSEP was strongly inhibited by itraconazole and hydroxyitraconazole (3 and 17 μM, respectively). Fluconazole and voriconazole did not inhibit any transport for >60%. Micafungin uniquely inhibited all transporters, with strong inhibition of MRP4 (4 μM). Anidulafungin and caspofungin showed strong inhibition of BCRP (7 and 6 μM, respectively). Amphotericin B only weakly inhibited BCRP-mediated transport (127 μM). Despite their wide range of DDIs, azole antifungals exhibit selective inhibition on efflux transporters. Although echinocandins display low potential for clinically relevant DDIs, they demonstrate potent in vitro inhibitory activity. This suggests that inhibition of ABC transporters plays a crucial role in the inexplicable (non-cytochrome P450-mediated) DDIs with antifungal drugs.
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9
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Caetano-Pinto P, Janssen MJ, Gijzen L, Verscheijden L, Wilmer MJ, Masereeuw R. Fluorescence-Based Transport Assays Revisited in a Human Renal Proximal Tubule Cell Line. Mol Pharm 2016; 13:933-44. [DOI: 10.1021/acs.molpharmaceut.5b00821] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Pedro Caetano-Pinto
- Department
of Pharmacology and Toxicology, Radboud university medical center, Radboud Institute for Molecular Life Sciences, 6500 HB Nijmegen, The Netherlands
- Division
of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, 3508 TB Utrecht, The Netherlands
| | - Manoe J. Janssen
- Department
of Pharmacology and Toxicology, Radboud university medical center, Radboud Institute for Molecular Life Sciences, 6500 HB Nijmegen, The Netherlands
- Division
of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, 3508 TB Utrecht, The Netherlands
| | - Linda Gijzen
- Department
of Pharmacology and Toxicology, Radboud university medical center, Radboud Institute for Molecular Life Sciences, 6500 HB Nijmegen, The Netherlands
| | - Laurens Verscheijden
- Department
of Pharmacology and Toxicology, Radboud university medical center, Radboud Institute for Molecular Life Sciences, 6500 HB Nijmegen, The Netherlands
| | - Martijn J.G. Wilmer
- Department
of Pharmacology and Toxicology, Radboud university medical center, Radboud Institute for Molecular Life Sciences, 6500 HB Nijmegen, The Netherlands
| | - Rosalinde Masereeuw
- Department
of Pharmacology and Toxicology, Radboud university medical center, Radboud Institute for Molecular Life Sciences, 6500 HB Nijmegen, The Netherlands
- Division
of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, 3508 TB Utrecht, The Netherlands
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10
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Gozalpour E, Wilmer MJ, Bilos A, Masereeuw R, Russel FGM, Koenderink JB. Heterogeneous transport of digitalis-like compounds by P-glycoprotein in vesicular and cellular assays. Toxicol In Vitro 2015; 32:138-45. [PMID: 26708294 DOI: 10.1016/j.tiv.2015.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 12/08/2015] [Accepted: 12/15/2015] [Indexed: 01/28/2023]
Abstract
Digitalis-like compounds (DLCs), the ancient medication of heart failure and Na,K-ATPase inhibitors, are characterized by their toxicity. Drug-drug interactions (DDIs) at absorption and excretion levels play a key role in their toxicity, hence, knowledge about the transporters involved might prevent these unwanted interactions. In the present study, the transport of fourteen DLCs with human P-glycoprotein (P-gp; ABCB1) was studied using a liquid chromatography-mass spectrometry (LC-MS) quantification method. DLC transport by P-gp overexpressing Madin-Darby canine kidney (MDCK) and immortalized human renal cells (ciPTEC) was compared to vesicular DLC transport. Previously, we identified convallatoxin as a substrate using membrane vesicles overexpressing P-gp; however, we could not measure transport of other DLCs in this assay (Gozalpour et al., 2014a). Here, we showed that lipophilic digitoxin, digoxigenin, strophanthidin and proscillaridin A are P-gp substrates in cellular accumulation assays, whereas the less lipophilic convallatoxin was not. P-gp function in the cellular accumulation assays depends on the entrance of lipophilic compounds by passive diffusion, whereas the vesicular transport assay is more appropriate for hydrophilic substrates. In conclusion, we identified digitoxin, digoxigenin, strophanthidin and proscillaridin A as P-gp substrates using cellular accumulation assays and recognized lipophilicity as an important factor in selecting a suitable transport assay.
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Affiliation(s)
- Elnaz Gozalpour
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, The Netherlands
| | - Martijn J Wilmer
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, The Netherlands
| | - Albert Bilos
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, The Netherlands
| | - Rosalinde Masereeuw
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, The Netherlands
| | - Frans G M Russel
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, The Netherlands
| | - Jan B Koenderink
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, The Netherlands.
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