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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
Elena Puris, Markku Pasanen, Mikko Gynther, Merja R Häkkinen, Jussi Pihlajamäki, Tapani Keränen, Paavo Honkakoski, Hannu Raunio, Aleksanteri Petsalo
Cocktail phenotyping using specific probe drugs for cytochrome P450 (CYP) enzymes provides information on the real-time activity of multiple CYPs. We investigated different sample preparation techniques and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with simple protein precipitation for the analysis of nine CYP probe drugs and their metabolites in human serum and urine. Specific CYP probe drugs (melatonin, CYP1A2; nicotine, CYP2A6; bupropion, CYP2B6; repaglinide, CYP2C8; losartan, CYP2C9; omeprazole, CYP2C19 and CYP3A4; dextromethorphan, CYP2D6; chlorzoxazone, CYP2E; midazolam, CYP3A4) and their main metabolites, with the exception of 3'-hydroxyrepaglinide, were quantified in human serum and urine using the developed LC-MS/MS method...
October 12, 2016: Analytical and Bioanalytical Chemistry
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
Yasotha Devi Muthiah, Chin Eng Ong, Siti Amrah Sulaiman, Rusli Ismail
BACKGROUND: In Southeast Asia and many parts of the world, herbal products are increasingly used in parallel with modern medicine. OBJECTIVE: This study aimed to investigate the effects of herbs commonly used in Southeast Asia on activity of cytochrome P450 2C8 (CYP2C8), an important human hepatic enzyme in drug metabolism. MATERIALS AND METHODS: The selected herbs, such as Eurycoma longifolia Jack (ELJ), Labisia pumila (LP), Echinacea purpurea (EP), Andrographis paniculata (AP), and Ginkgo biloba (GB), were subjected to inhibition studies using an in vitro CYP2C8 activity marker, amodiaquine N-desethylase assay...
October 2016: Pharmacognosy Research
M V Varma, E Kimoto, R Scialis, Y Bi, J Lin, H Eng, A S Kalgutkar, A F El-Kattan, A D Rodrigues, L M Tremaine
Montelukast, a leukotriene receptor antagonist commonly prescribed for treatment of asthma, is primarily metabolized by Cytochrome P450 (CYP)2C8, and has been suggested as a probe substrate for investigating CYP2C8 activity in vivo. We evaluated the quantitative role of hepatic uptake transport in its pharmacokinetics and drug-drug interactions (DDIs). Montelukast was characterized with significant active uptake in human hepatocytes, and showed affinity towards organic anion transporting polypeptides (OATPs) in transfected cell systems...
September 20, 2016: Clinical Pharmacology and Therapeutics
Xiaolong Zhang, Meng Zhang, Yong Hou, Liqin Xu, Weidong Li, Zhihui Zou, Chunxiao Liu, Abai Xu, Song Wu
Cell-to-cell expression heterogeneity within a single tumor is a common phenotype among various cancer types including squamous cell carcinoma. To further study the fundamentals and importance of heterogeneity of cell functions and its potential mechanisms, we performed single-cell RNA-seq (scRNA-seq) on human squamous cell carcinoma of the bladder (SCCB) and its corresponding physiologically normal epithelia. Extensive differentially expressed genes were uncovered by comparing cancer and normal single cells, which were preferentially enriched in cancer-correlated pathways, such as p53 signaling and bladder cancer pathway...
September 1, 2016: Oncotarget
Catia Marzolini, Rajith Rajoli, Manuel Battegay, Luigia Elzi, David Back, Marco Siccardi
BACKGROUND: Antiretroviral drugs are among the therapeutic agents with the highest potential for drug-drug interactions (DDIs). In the absence of clinical data, DDIs are mainly predicted based on preclinical data and knowledge of the disposition of individual drugs. Predictions can be challenging, especially when antiretroviral drugs induce and inhibit multiple cytochrome P450 (CYP) isoenzymes simultaneously. METHODS: This study predicted the magnitude of the DDI between efavirenz, an inducer of CYP3A4 and inhibitor of CYP2C8, and dual CYP3A4/CYP2C8 substrates (repaglinide, montelukast, pioglitazone, paclitaxel) using a physiologically based pharmacokinetic (PBPK) modeling approach integrating concurrent effects on CYPs...
September 7, 2016: Clinical Pharmacokinetics
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
Ana Carolina Rios Silvino, Gabriel Luiz Costa, Flávia Carolina Faustino de Araújo, David Benjamin Ascher, Douglas Eduardo Valente Pires, Cor Jesus Fernandes Fontes, Luzia Helena Carvalho, Cristiana Ferreira Alves de Brito, Tais Nobrega Sousa
Although Plasmodium vivax relapses are classically associated with hypnozoite activation, it has been proposed that a proportion of these cases are due to primaquine (PQ) treatment failure caused by polymorphisms in cytochrome P-450 2D6 (CYP2D6). Here, we present evidence that CYP2D6 polymorphisms are implicated in PQ failure, which was reinforced by findings in genetically similar parasites, and may explain a number of vivax relapses. Using a computational approach, these polymorphisms were predicted to affect the activity of CYP2D6 through changes in the structural stability that could lead to disruption of the PQ-enzyme interactions...
2016: PloS One
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
Xianbao Shi, Gang Zhang, Brianna Mackie, Shuman Yang, Jian Wang, Lina Shan
Psoralidin has shown a variety of biological and pharmacological activities such as anti-tumor anti-oxidant, anti-bacterial, anti-depressant and anti-inflammatory activities. Herein, we reported the metabolism of psoralidin among different species and its inhibitory effect against UGTs and CYP450s. Liquid chromatography was used to investigate the inhibitory activity of psoralidin against ten different UGTs and eight distinct CYP450 isoforms. In addition, we characterized the CYP450 isoforms involved in the psoralidin metabolism on the basis of chemical inhibition studies and screening assays with recombinant human cytochrome P450s...
September 1, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Robert S Foti, Philippe Diaz, Dominique Douguet
The CYP26s are responsible for metabolizing retinoic acid and play an important role in maintaining homeostatic levels of retinoic acid. Given the ability of CYP2C8 to metabolize retinoic acid, we evaluated the potential for CYP2C8 inhibitors to also inhibit CYP26. In vitro assays were used to evaluate the inhibition potencies of CYP2C8 inhibitors against CYP26A1 and CYP26B1. Using tazarotenic acid as a substrate for CYP26, IC50 values for 17 inhibitors of CYP2C8 were determined for CYP26A1 and CYP26B1, ranging from ∼20 nM to 100 μM, with a positive correlation observed between IC50s for CYP2C8 and CYP26A1...
July 17, 2016: Journal of Enzyme Inhibition and Medicinal Chemistry
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
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