- Engineering Macaca fascicularis cytochrome P450 2C20 to reduce animal testing for new drugs
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In order to develop in vitro methods as an alternative to P450 animal testing in the drug discovery process, two main requisites are necessary: 1) gathering of data on animal homologues of the human P450 enzymes, currently very limited, and 2) bypassing t
- Rua, Francesco,Sadeghi, Sheila J.,Castrignanò, Silvia,Di Nardo, Giovanna,Gilardi, Gianfranco
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- Functional characterization of 12 allelic variants of CYP2C8 by assessment of paclitaxel 6α-hydroxylation and amodiaquine N-deethylation
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Cytochrome P450 2C8 (CYP2C8) is one of the enzymes primarily responsible for the metabolism of many drugs, including paclitaxel and amodiaquine. CYP2C8 genetic variants contribute to interindividual variations in the therapeutic efficacy and toxicity of p
- Tsukada, Chiharu,Saito, Takahiro,Maekawa, Masamitsu,Mano, Nariyasu,Oda, Akifumi,Hirasawa, Noriyasu,Hiratsuka, Masahiro
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- Synthesis of 6α-hydroxypaclitaxel, the major human metabolite of paclitaxel
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6α-Hydroxypaclitaxel, the major human metabolite of paclitaxel, was synthesized via epimerization of 6α-hydroxy-7-epipaclitaxel, which was prepared from paclitaxel in four steps in high yield. Various epimerization conditions were investigated, and the op
- Yuan, Haiqing,Kingston, David G. I.
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- Structural and functional insights into polymorphic enzymes of cytochrome P450 2C8
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The cytochrome P450 (CYP) superfamily plays a key role in the oxidative metabolism of a wide range of drugs and exogenous chemicals. CYP2C8 is the principal enzyme responsible for the metabolism of the anti-cancer drug paclitaxel in the human liver. Nearl
- Jiang, Hualin,Zhong, Fangfang,Sun, Lu,Feng, Weiyue,Huang, Zhong-Xian,Tan, Xiangshi
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- In vitro evaluations for pharmacokinetic drug-drug interactions of a novel serotonin-dopamine activity modulator, brexpiprazole
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Brexpiprazole, a serotonin-dopamine activity modulator, is indicated for the treatment of schizophrenia and also adjunctive therapy to antidepressants for the treatment of Major Depressive Disorder. To determine the drug–drug interaction risk for cytochrome P450, and SLC and ABC transporters, brexpiprazole and its metabolite, DM-3411 were assessed in this in?vitro investigation. Brexpiprazole exhibited weak inhibitory effects (IC50 >13 μmol/L) on CYP2C9, CYP2C19, CYP2D6 and CYP3A4 activities, but had moderate inhibitor activity on CYP2B6 (IC50 8.19 μmol/L). The ratio of systemic unbound concentration (3.8 nmol/L) to the Ki value was sufficiently low. DM-3411 had comparable inhibitory potentials with brexpiprazole only for CYP2D6 and CYP3A4. The mRNA expressions of CYP1A2, CYP2B6 and CYP3A4 were not changed by the exposure of brexpiprazole to human hepatocytes. Brexpiprazole and DM-3411 exhibited weak or no inhibitory effects for hepatic and renal transporters (OATPs, OATs, OCTs, MATE1, and BSEP), except for MATE-2K (0.156 μmol/L of DM-3411), even for which the ratio to systemic unbound concentration (5.3 nmol/L) was sufficiently low. Brexpiprazole effected the functions of P-gp and BCRP with IC50 values of 6.31 and 1.16 μmol/L, respectively, however, the pharmacokinetic alteration was not observed in the clinical concomitant study on P-gp and BCRP substrates. These in?vitro data suggest that brexpiprazole is unlikely to cause clinically relevant drug interactions resulting from the effects on CYPs or transporters mediating the absorption, metabolism, and/or disposition of co-administered drugs.
- Sasabe, Hiroyuki,Koga, Toshihisa,Furukawa, Masayuki,Matsunaga, Masayuki,Sasahara, Katsunori,Hashizume, Kenta,Oozone, Yoshihiro,Amunom, Immaculate,Torii, Mikako,Umehara, Ken,Kashiyama, Eiji,Takeuchi, Kenji
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supporting information
p. 522 - 535
(2021/03/19)
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- Evaluation of Cytochrome P450 Selectivity for Hydralazine as an Aldehyde Oxidase Inhibitor for Reaction Phenotyping
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Hydralazine has been reported as a selective mechanism-based inactivator of aldehyde oxidase (AO) and it is widely used in the pharmaceutical industry for reaction phenotyping to estimate fraction metabolized by AO and to identify AO substrates. In this study, however, hydralazine was found to inhibit CYP1A2, 2B6, 2D6, and 3A in human suspension hepatocytes under reaction phenotyping assay conditions, at concentrations that chemically knocked out most of the AO activities (≥50 μM). Furthermore, hydralazine is a time-dependent inhibitor of CYP1A2. Based on these findings, precautions need to be taken when using hydralazine as an AO inhibitor for in vitro studies because fraction metabolized by AO is likely to be overestimated and the likelihood of false positives in identifying AO substrates increases.
- Yang, Xin,Johnson, Nathaniel,Di, Li
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p. 1627 - 1630
(2019/01/16)
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- The effect of flavonoid aglycones on the CYP1A2, CYP2A6, CYP2C8 and CYP2D6 enzymes activity
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Cytochromes P450 are major metabolic enzymes involved in the biotransformation of xenobiotics. The majority of xenobiotics are metabolized in the liver, in which the highest levels of cytochromes P450 are expressed. Flavonoids are natural compounds to which humans are exposed through everyday diet. In the previous study, selected flavonoid aglycones showed inhibition of CYP3A4 enzyme. Thus, the objective of this study was to determine if these flavonoids inhibit metabolic activity of CYP1A2, CYP2A6, CYP2C8, and CYP2D6 enzymes. For this purpose, the O-deethylation reaction of phenacetin was used for monitoring CYP1A2 enzyme activity, coumarin 7-hydroxylation for CYP2A6 enzyme activity, 6-α-hydroxylation of paclitaxel for CYP2C8 enzyme activity, and dextromethorphan O-demethylation for CYP2D6 enzyme activity. The generated metabolites were monitored by high-performance liquid chromatography coupled with diode array detection. Hesperetin, pinocembrin, chrysin, isorhamnetin, and morin inhibited CYP1A2 activity; apigenin, tangeretin, galangin, and isorhamnetin inhibited CYP2A6 activity; and chrysin, chrysin-dimethylether, and galangin inhibited CYP2C8. None of the analyzed flavonoids showed inhibition of CYP2D6. The flavonoids in this study were mainly reversible inhibitors of CYP1A2 and CYP2A6, while the inhibition of CYP2C8 was of mixed type (reversible and irreversible). The most prominent reversible inhibitor of CYP1A2 was chrysin, and this was confirmed by the docking study.
- Boji?, Mirza,Kond?a, Martin,Rimac, Hrvoje,Benkovi?, Goran,Male?, ?eljan
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- Heme-thiolate sulfenylation of human cytochrome P450 4A11 functions as a redox switch for catalytic inhibition
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Cytochrome P450 (P450, CYP) 4A11 is a human fatty acid ω-hydroxylase that catalyzes the oxidation of arachidonic acid to the eicosanoid 20-hydroxyeicosatetraenoic acid (20-HETE), which plays important roles in regulating blood pressure regulation. Variants of P450 4A11 have been associated with high blood pressure and resistance to anti-hypertensive drugs, and 20-HETE has both pro- and antihypertensive properties relating to increased vasoconstriction and natriuresis, respectively. These physiological activities are likely influenced by the redox environment, but the mechanisms are unclear. Here, we found that reducing agents (e.g. dithiothreitol and tris(2-carboxyethyl) phosphine) strongly enhanced the catalytic activity of P450 4A11, but not of 10 other human P450s tested. Conversely, added H2O2 attenuated P450 4A11 catalytic activity. Catalytic roles of five of the potentially eight implicated Cys residues of P450 4A11 were eliminated by site-directed mutagenesis. Using an isotope-coded dimedone/iododimedone-labeling strategy and mass spectrometry of peptides, we demonstrated that the heme-thiolate cysteine (Cys-457) is selectively sulfenylated in an H2O2 concentration-dependent manner. This sulfenylation could be reversed by reducing agents, including dithiothreitol and dithionite. Of note, we observed heme ligand cysteine sulfenylation of P450 4A11 ex vivo in kidneys and livers derived from CYP4A11 transgenic mice. We also detected sulfenylation of murine P450 4a12 and 4b1 heme peptides in kidneys. To our knowledge, reversible oxidation of the heme thiolate has not previously been observed in P450s and may have relevance for 20-HETE-mediated functions.
- Albertolle, Matthew E.,Kim, Donghak,Nagy, Leslie D.,Yun, Chul-Ho,Pozzi, Ambra,Savas, üzen,Johnson, Eric F.,Guengerich, F. Peter
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p. 11230 - 11242
(2017/08/08)
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- Influence of CYP2C8 polymorphisms on the hydroxylation metabolism of paclitaxel, repaglinide and ibuprofen enantiomers in vitro
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CYP2C8 plays an important role in the metabolism of various drugs, such as paclitaxel, repaglinide and ibuprofen. Polymorphisms in the CYP2C8 gene were shown to influence interindividual differences in the pharmacokinetics of paclitaxel, repaglinide and i
- Yu, Lushan,Shi, Da,Ma, Liping,Zhou, Quan,Zeng, Su
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p. 278 - 287
(2013/07/26)
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- Cytochrome P450 metabolic activities in the small intestine of cynomolgus macaques bred in cambodia, china, and indonesia
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Summary: Cynomolgus macaques, used in drug metabolism studies due to their evolutionary closeness to humans, are mainly bred in Asian countries, including Cambodia, China, and Indonesia. Cytochromes P450 (P450s) are important drug-metabolizing enzymes, present in the liver and small intestine, major drug metabolizing organs. Previously, our investigation did not find statistically significant differences in hepatic P450 metabolic activities measured in cynomolgus macaques bred in Cambodia (MacfaCAM) and China (MacfaCHN). In the present study, P450 metabolic activity was investigated in the small intestine of MacfaCAM and MacfaCHN, and cynomolgus macaques bred in Indonesia (MacfaIDN) using P450 substrates, including 7-ethoxyresorufin, coumarin, bupropion, paclitaxel, diclofenac, S-mephenytoin, bufuralol, chlorzoxazone, and testosterone. The results indicated that P450 metabolic activity of the small intestine was not statistically significantly different (2.0-fold) in MacfaCAM, MacfaCHN, and MacfaIDN. In addition, statistically significant sex differences were not observed (2.0-fold) in any P450 metabolic activity in MacfaCAM as supported by mRNA expression results. These results suggest that P450 metabolic activity of the small intestine does not significantly differ statistically among MacfaCAM, MacfaCHN, and MacfaIDN.
- Nakanishi, Yasuharu,Yamashita, Hiroyuki,Yoshikawa, Tsuyoshi,Tominaga, Takeshi,Nojiri, Koichiro,Sunaga, Yoshiharu,Muneoka, Atsunobu,Iwasaki, Kazuhide,Utoh, Masahiro,Nakamura, Chika,Yamazaki, Hiroshi,Uno, Yasuhiro
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p. 510 - 513
(2014/02/14)
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- Identification of human cytochrome P450s that metabolise anti-parasitic drugs and predictions of in vivo drug hepatic clearance from in vitro data
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Objective: Knowledge about the metabolism of anti-parasitic drugs (APDs) will be helpful in ongoing efforts to optimise dosage recommendations in clinical practise. This study was performed to further identify the cytochrome P450 (CYP) enzymes that metabolise major APDs and evaluate the possibility of predicting in vivo drug clearances from in vitro data. Methods: In vitro systems, rat and human liver microsomes (RLM, HLM) and recombinant cytochrome P450 (rCYP), were used to determine the intrinsic clearance (CLint) and identify responsible CYPs and their relative contribution in the metabolism of 15 commonly used APDs. Results and discussion: CLint determined in RLM and HLM showed low (r2=0.50) but significant (Pint values were scaled to predict in vivo hepatic clearance (CLH) using the 'venous equilibrium model'. The number of compounds with in vivo human CL data after intravenous administration was low (n=8), and the range of CL values covered by these compounds was not appropriate for a reasonable quantitative in vitro-in vivo correlation analysis. Using the CLH predicted from the in vitro data, the compounds could be classified into three different categories: high-clearance drugs (> 70% liver blood flow; amodiaquine, praziquantel, albendazole, thiabendazole), low-clearance drugs (int drug categories. The identified CYPs for some of the drugs provide a basis for how these drugs are expected to behave pharmacokinetically and help in predicting drug-drug interactions in vivo.
- Li, Xue-Qing,Bjoerkman, Anders,Andersson, Tommy B.,Gustafsson, Lars L.,Masimirembwa, Collen
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p. 429 - 442
(2007/10/03)
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- Stereospecific synthesis of the major human metabolite of paclitaxel
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The stereospecific synthesis of 6-α-hydroxy paclitaxel 10, the major human metabolite of paclitaxel, is described. The 6,7-α-diol 4, obtained from paclitaxel, is converted to the 6,7-β-cyclic sulfate followed by nitrate addition and reduction to afford the title compound. (C) 2000 Elsevier Science Ltd.
- Wittman, Mark D.,Kadow, John F.,Vyas, Dolatrai M.
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p. 4729 - 4731
(2007/10/03)
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- Synthesis and Biological Evaluation of Paclitaxel Analogs Modified in Ring C
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Both 7-deoxy-7α-azidopaclitaxel (6) and 7-deoxy-Δ6,7-paclitaxel (4) can be prepared from paclitaxel-7-O-triflate (2b).Oxidation of 7-deoxy-Δ6,7-paclitaxel with dioxirane yields the epoxide 7, while oxidation with osmium tetroxide yie
- Liang, Xian,Kingston, David G. I.,Lin, Chii M.,Hamel, Ernest
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p. 2901 - 2904
(2007/10/02)
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