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Siu W Lam, Charlotte N Frederiks, Tahar van der Straaten, Aafke H Honkoop, Henk-Jan Guchelaar, Epie Boven
BACKGROUND: The purpose of this study was to evaluate single-nucleotide polymorphisms (SNPs) in genes encoding key metabolising enzymes or involved in pharmacodynamics for possible associations with paclitaxel-induced peripheral neuropathy. METHODS: The study population consists of 188 women from the multicenter, randomised, phase II ATX trial (BOOG2006-06; EudraCT number 2006-006058-83) that received paclitaxel and bevacizumab without or with capecitabine as first-line palliative therapy of HER2-negative metastatic breast cancer...
October 13, 2016: British Journal of Cancer
Yan Gong, Zhuo Shao, Zhongjie Fu, Matthew L Edin, Ye Sun, Raffael G Liegl, Zhongxiao Wang, Chi-Hsiu Liu, Samuel B Burnim, Steven S Meng, Fred B Lih, John Paul SanGiovanni, Darryl C Zeldin, Ann Hellström, Lois E H Smith
Neovascular eye diseases including retinopathy of prematurity, diabetic retinopathy and age-related-macular-degeneration are major causes of blindness. Fenofibrate treatment in type 2 diabetes patients reduces progression of diabetic retinopathy independent of its peroxisome proliferator-activated receptor (PPAR)α agonist lipid lowering effect. The mechanism is unknown. Fenofibrate binds to and inhibits cytochrome P450 epoxygenase (CYP)2C with higher affinity than to PPARα. CYP2C metabolizes ω-3 long-chain polyunsaturated fatty acids (LCPUFAs)...
September 30, 2016: EBioMedicine
Yongjie Zhang, Nico P E Vermeulen, Jan N M Commandeur
AIMS: Oxidative bioactivation of amodiaquine (AQ) by cytochrome P450s to a reactive quinoneimine is considered as an important mechanism underlying its idiosyncratic hepatotoxicity. However, because internal exposure to its major metabolite N-desethylamodiaquine (DEAQ) is up to 240 fold higher than AQ, bioactivation of DEAQ might significant contribute to covalent binding. The aim of the present study was to compare the kinetics of bioactivation of AQ and DEAQ by human liver microsomes and to characterize the CYPs involved in bioactivation of AQ and DEAQ...
October 8, 2016: British Journal of Clinical Pharmacology
Tulay Kus, Gokmen Aktas, Mehmet Emin Kalender, Abdullah Tuncay Demiryurek, Mustafa Ulasli, Serdar Oztuzcu, Alper Sevinc, Seval Kul, Celaletdin Camci
BACKGROUND: Interindividual variability of pharmacogenetics may account for unpredictable neurotoxicities of taxanes. METHODS: From March 2011 to June 2015, female patients with operable breast cancer who had received docetaxel- or paclitaxel-containing adjuvant chemotherapy were included in this study. All patients were treated with single-agent paclitaxel intravenously (IV) 175 mg/m(2) every 3 weeks for four cycles, or IV 80 mg/m(2) weekly for 12 cycles, and IV 100 mg/m(2) docetaxel for four cycles as adjuvant treatment...
2016: OncoTargets and Therapy
Aleksi Tornio, Pertti J Neuvonen, Mikko Niemi, Janne T Backman
INTRODUCTION: Cytochrome P450 (CYP) 2C8 is a drug metabolizing enzyme of major importance. The lipid-lowering drug gemfibrozil has been identified as a strong inhibitor of CYP2C8 in vivo. This effect is due to mechanism-based inhibition of CYP2C8 by gemfibrozil 1-O-β-glucuronide. In vivo, gemfibrozil is a fairly selective CYP2C8 inhibitor, which lacks significant inhibitory effect on other CYP enzymes. Gemfibrozil can, however, have a smaller but clinically meaningful inhibitory effect on membrane transporters, such as organic anion transporting polypeptide 1B1 and organic anion transporter 3...
August 22, 2016: Expert Opinion on Drug Metabolism & Toxicology
Vikram Gota, Girish Chinnaswamy, Tushar Vora, Sanhita Rath, Akanksha Yadav, Murari Gurjar, Gareth Veal, Purna Kurkure
PURPOSE: To compare the pharmacokinetics of 13-cis retinoic acid (13-cisRA) between Indian and UK neuroblastoma patients receiving comparable treatment, alongside measures of toxicity and response. METHODS: 13-cisRA (160 mg/m(2)/day) was administered to 36 patients ≤16 years in two divided doses. Plasma 13-cisRA concentrations were determined on days 1 and 14 of cycles 1 and 4 of treatment. Area under the plasma concentration-time curve (AUC0-6h) was estimated using non-compartment modelling...
October 2016: Cancer Chemotherapy and Pharmacology
Renata Szalai, Kinga Hadzsiev, Bela Melegh
The cytochrome P450 drug metabolizing enzymes are highly polymorphic and show inter-individual differences in variability in drug response, which varies widely also with ethnicity. This study aimed to summarize the available data on genetic polymorphisms associated with cytochrome enzymes conducted in Roma populations. Our goal was to compare the frequency of the variant alleles, genotypes and predicted phenotypes with corresponding rates from other populations. We carried out a systematic review including the papers published on the pharmacogenetically relevant variants of cytochrome P450 genes related to Roma population...
August 8, 2016: Current Medicinal Chemistry
Johan Monbaliu, Martha Gonzalez, Apexa Bernard, James Jiao, Carlo Sensenhauser, Jan Snoeys, Hans Stieltjes, Inneke Wynant, Johan W Smit, Caly Chien
Abiraterone acetate, the prodrug of the cytochrome P450 C17 inhibitor abiraterone, plus prednisone is approved for treatment of metastatic castration-resistant prostate cancer. We explored whether abiraterone interacts with drugs metabolized by CYP2C8, an enzyme responsible for the metabolism of many drugs. Abiraterone acetate and abiraterone and its major metabolites, abiraterone sulfate and abiraterone sulfate N-oxide, inhibited CYP2C8 in human liver microsomes, with IC50 values near or below the peak total concentrations observed in patients with metastatic castration-resistant prostate cancer (IC50 values: 1...
October 2016: Drug Metabolism and Disposition: the Biological Fate of Chemicals
Soo-Jin Kim, Takashi Yoshikado, Ichiro Ieiri, Kazuya Maeda, Miyuki Kimura, Shin Irie, Hiroyuki Kusuhara, Yuichi Sugiyama
Clopidogrel is reported to be associated with cerivastatin-induced rhabdomyolysis, and clopidogrel and its metabolites are capable of inhibiting CYP2C8 and OATP 1B1 in vitro. The objective of the present study was to identify the mechanism of clopidogrel-mediated drug-drug interactions (DDIs) on the pharmacokinetics of OATP1B1 and/or CYP2C8 substrates in vivo. A clinical cassette small-dose study using OATPs, CYP2C8, and OATP1B1/CYP2C8 probe drugs (pitavastatin, pioglitazone, and repaglinide, respectively) with or without the coadministration of either 600 mg rifampicin (an inhibitor for OATPs), 200 mg trimethoprim (an inhibitor for CYP2C8), or 300 mg clopidogrel was performed, and the area under the concentration-time curve (AUC) ratios (AUCRs) for probe substrates were predicted using a static model...
October 2016: Drug Metabolism and Disposition: the Biological Fate of Chemicals
Yan Gong, Zhongjie Fu, Matthew L Edin, Chi-Hsiu Liu, Zhongxiao Wang, Zhuo Shao, Thomas W Fredrick, Nicholas J Saba, Peyton C Morss, Samuel B Burnim, Steven S Meng, Fred B Lih, Kin Sing Stephen Lee, Elizabeth P Moran, John Paul SanGiovanni, Ann Hellström, Bruce D Hammock, Darryl C Zeldin, Lois E H Smith
OBJECTIVE: Pathological ocular neovascularization is a major cause of blindness. Increased dietary intake of ω-3 long-chain polyunsaturated fatty acids (LCPUFA) reduces retinal neovascularization and choroidal neovascularization (CNV), but ω-3 LCPUFA metabolites of a major metabolizing pathway, cytochrome P450 oxidase (CYP) 2C, promote ocular pathological angiogenesis. We hypothesized that inhibition of CYP2C activity will add to the protective effects of ω-3 LCPUFA on neovascular eye diseases...
September 2016: Arteriosclerosis, Thrombosis, and Vascular Biology
Matthieu Levavasseur, Sophie Darras, Laurent Mortier, Céline Goeminne, Marine Auffret, Marie Bertrand
Melanoma is a major public health problem. In recent years, it has been shown that melanoma can be characterized by specific oncogenes mutations such as the BRAF mutation, leading to the development of new therapeutic drugs. Dabrafenib is an inhibitor of BRAF, approved as a first-line treatment of metastatic or unresectable stage 3 or 4 melanoma with the BRAF mutation. Few studies have evaluated the drug interaction potential of dabrafenib. This molecule is an enzyme inducer that increases the synthesis of drug-metabolizing enzymes, including CYP3A4, CYP2B6, CYP2C8, CYP2C9, CYP2C19, and UGT enzymes...
October 2016: Melanoma Research
Yasutaka Shinoda, Michio Kimura, Eiseki Usami, Hiroki Asano, Tomoaki Yoshimura
Paclitaxel is mainly inactivated in vivo by cytochrome P5402C8 (CYP2C8). In recent years, the clopidogrel metabolite has been reported to potently inhibit CYP2C8. However, clinical information regarding the interaction between these two drugs is limited. To the best of our knowledge, this is the first retrospective study investigating the potential for the drug interaction between paclitaxel and clopidogrel. A total of 8 cases in which clopidogrel and paclitaxel were used in combination were examined. The incidence of adverse events and discontinuation rate in these cases were assessed...
July 2016: Biomedical Reports
Michaela Kopečná-Zapletalová, Kristýna Krasulová, Pavel Anzenbacher, Petr Hodek, Eva Anzenbacherová
1. The possibility of interaction of isoflavonoids with concomitantly taken drugs to determined isoflavonoids safety was studied. Inhibition of nine forms of cytochrome P450 (CYP3A4, CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2C9, CYP2D6 and CYP2E1) by 12 isoflavonoids (daidzein, genistein, biochanin A, formononetin, glycitein, equol and six glucosides, daidzin, puerarin, genistin, sissotrin, ononin and glycitin) was studied systematically. 2. The most potent inhibitors were genistein and daidzein inhibiting noncompetitively the CYP2C9 with Ki of 35...
June 17, 2016: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
Adem Y Dawed, Louise Donnelly, Roger Tavendale, Fiona Carr, Graham Leese, Colin N A Palmer, Ewan R Pearson, Kaixin Zhou
OBJECTIVE: Thiazolidinediones (TZDs) are putatively transported into the liver by OATP1B1 (encoded by SLCO1B1) and metabolized by CYP450 2C8 enzyme (encoded by CYP2C8). While CYP2C8*3 has been shown to alter TZD pharmacokinetics, it has not been shown to alter efficacy. RESEARCH DESIGN AND METHODS: We genotyped 833 Scottish patients with type 2 diabetes treated with pioglitazone or rosiglitazone and jointly investigated association of variants in these two genes with therapeutic outcome...
June 6, 2016: Diabetes Care
Matti K Itkonen, Aleksi Tornio, Mikko Neuvonen, Pertti J Neuvonen, Mikko Niemi, Janne T Backman
The glucose-lowering drug pioglitazone undergoes hepatic CYP2C8-mediated biotransformation to its main metabolites. The antiplatelet drug clopidogrel is metabolized to clopidogrel acyl-β-d-glucuronide, which was recently found to be a strong time-dependent inhibitor of CYP2C8 in humans. Therefore, we studied the effect of clopidogrel on the pharmacokinetics of pioglitazone. In a randomized crossover study, 10 healthy volunteers ingested either 300 mg of clopidogrel on day 1, and 75 mg on days 2 and 3, or placebo...
August 2016: Drug Metabolism and Disposition: the Biological Fate of Chemicals
Vinay Kumar Tripathi, Vivek Kumar, Ankita Pandey, Pankhi Vatsa, Anupam Dhasmana, Rajat Pratap Singh, Sri Hari Chandan Appikonda, Inho Hwang, Mohtashim Lohani
Expression of various cytochrome P450s (CYPs) in mammalian brain cells is well documented. However, such studies are hampered in neural/glial cells of human origin due to nonavailability of human brain cells. To address this issue, we investigated the expression and inducibility of CYP2C8 and CYP3A4 and their responsiveness against cyclophosphamide (CPA) and organophosphorus pesticide monocrotophos (MCP), a known developmental neurotoxicant in human neural (SH-SY5Y) and glial (U373-MG) cell lines. CPA induced significant expression of CYP2C8 and CYP3A4 in both types of cells in a time-dependent manner...
May 20, 2016: Molecular Neurobiology
Jun Zhou, Qiang Wen, Sai-Fei Li, Yun-Fei Zhang, Na Gao, Xin Tian, Yan Fang, Jie Gao, Ming-Zhu Cui, Xiao-Pei He, Lin-Jing Jia, Han Jin, Hai-Ling Qiao
The lack of information concerning individual variation in drug-metabolizing enzymes is one of the most important obstacles for designing personalized medicine approaches for hepatocellular carcinoma (HCC) patients. To assess cytochrome P450 (CYP) in the metabolism of endogenous and exogenous molecules in an HCC setting, the activity changes of 10 major CYPs in microsomes from 105 normal and 102 HCC liver tissue samples were investigated. We found that CYP activity values expressed as intrinsic clearance (CLint) differed between HCC patients and control subjects...
May 18, 2016: Oncotarget
Paul Martin, Michael Gillen, David Millson, Stuart Oliver, Clive Brealey, Dominic Surry, David Sweeny, David Lau, Philip Leese
Fostamatinib is a prodrug that undergoes gastrointestinal tract dephosphorylation to form the active metabolite, R406. Here we report its cytochrome P450-inducing potential. In vitro, R406 3 and 10 μM induced CYP2C8 to levels representing 53% and 75%, respectively, of the level achieved by the positive control, rifampicin. Induction of other enzymes was minor. The effect of fostamatinib (100 mg twice daily) on the pharmacokinetics of a single oral 30-mg dose of the CYP2C8 substrate pioglitazone and its metabolite, hydroxy pioglitazone, was then investigated (open-label, nonrandomized, 2-period phase I study [n = 15])...
May 2016: Clinical Pharmacology in Drug Development
Soon-Sang Kwon, Ju-Hyun Kim, Hyeon-Uk Jeong, Yong Yeon Cho, Sei-Ryang Oh, Hye Suk Lee
Aschantin is a bioactive neolignan found in Magnolia flos with antiplasmodial, Ca(2+)-antagonistic, platelet activating factor-antagonistic, and chemopreventive activities. We investigated its inhibitory effects on the activities of eight major human cytochrome P450 (CYP) and uridine 5'-diphospho-glucuronosyltransferase (UGT) enzymes of human liver microsomes to determine if mechanistic aschantin-enzyme interactions were evident. Aschantin potently inhibited CYP2C8-mediated amodiaquine N-de-ethylation, CYP2C9-mediated diclofenac 4'-hydroxylation, CYP2C19-mediated [S]-mephenytoin 4'-hydroxylation, and CYP3A4-mediated midazolam 1'-hydroxylation, with Ki values of 10...
2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Valon Krasniqi, Aleksandar Dimovski, Iva Klarica Domjanović, Ivan Bilić, Nada Božina
Interindividual variability in drug metabolism is an important cause of adverse drug reactions and variability in drug efficiency. Polymorphisms of cytochrome P450 (CYPs) genes have a significant effect on drug metabolism and toxicity. This review brings an update about how genetic polymorphisms of CYP2C8 and CYP2C9 enzymes affect the disposition and clinical outcomes of ibuprofen and diclofenac, two of the most common pain relievers. The most common side effects associated with the influence of CYP2C8*3 and CYP2C9*2*3 variants on ibuprofen and diclofenac pharmacokinetics are hepatotoxicity and gastrointestinal bleeding...
March 2016: Arhiv za Higijenu Rada i Toksikologiju
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