Macaque CYP2C76 Encodes Cytochrome P450 Enzyme Not Orthologous to Any Human Isozymes

Uno, Yasuhiro; Fujino, Hideki; Iwasaki, Katsunori; Utoh, Masahiro

doi:10.2174/138920010791110854

Cited by 28 publications

(21 citation statements)

References 51 publications

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“…In addition, CYP2C76 has no ortholog in humans (Uno et al, 2006(Uno et al, , 2010, raising the possibility that CYP2C76 is involved in species differences in drug metabolism between cynomolgus monkeys and humans. CYP2C76 protein is expressed in the liver and catalyzes tolbutamide 4-hydroxylation and testosterone 2a-/16a-hydroxylation but not paclitaxel 6a-hydroxylation or S-mephenytoin 49-hydroxylation, showing substrate specificity differences from those of other cynomolgus monkey and human CYP2Cs (Uno et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of 89 Compounds for Identification of Substrates for Cynomolgus Monkey CYP2C76, a New Bupropion/Nifedipine Oxidase

et al. 2014

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Cynomolgus monkeys are widely used in preclinical studies during drug development because of their evolutionary closeness to humans, including their cytochrome P450s (P450s). Most cynomolgus monkey P450s are almost identical ( ‡90%) to human P450s; however, CYP2C76 has low sequence identity (approximately 80%) to any human CYP2Cs. Although CYP2C76 has no ortholog in humans and is partly responsible for species differences in drug metabolism between cynomolgus monkeys and humans, a broad evaluation of potential substrates for CYP2C76 has not yet been conducted. In this study, a screening of 89 marketed compounds, including human CYP2C and non-CYP2C substrates or inhibitors, was conducted to find potential CYP2C76 substrates. Among the compounds screened, 19 chemicals were identified as substrates for CYP2C76, including substrates for human CYP1A2 (7-ethoxyresorufin), CYP2B6 (bupropion), CYP2D6 (dextromethorphan), and CYP3A4/5 (dextromethorphan and nifedipine), and inhibitors for CYP2B6 (sertraline, clopidogrel, and ticlopidine), CYP2C8 (quercetin), CYP2C19 (ticlopidine and nootkatone), and CYP3A4/5 (troleandomycin). CYP2C76 metabolized a wide variety of the compounds with diverse structures. Among them, bupropion and nifedipine showed high selectivity to CYP2C76. As for nifedipine, CYP2C76 formed methylhydroxylated nifedipine, which was not produced by monkey CYP2C9, CYP2C19, or CYP3A4, as identified by mass spectrometry and estimated by a molecular docking simulation. This unique oxidative metabolite formation of nifedipine could be one of the selective marker reactions of CYP2C76 among the major CYP2Cs and CYP3As tested. These results suggest that monkey CYP2C76 contributes to bupropion hydroxylation and formation of different nifedipine oxidative metabolites as a result of its relatively large substrate cavity.

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Section: Introductionmentioning

confidence: 99%

Evaluation of 89 Compounds for Identification of Substrates for Cynomolgus Monkey CYP2C76, a New Bupropion/Nifedipine Oxidase

et al. 2014

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“…More than 20 P450s have been identified in cynomolgus monkey, and these enzymes are highly identical to orthologous human P450s (Uno et al, 2011a). The only exception is CYP2C76 that is not orthologous to any human P450 and is expressed as a functional drug-metabolizing enzyme in liver (Uno et al, 2010a). In cynomolgus monkey liver, other CYP2C genes encoding functional drug-metabolizing enzymes are also expressed, including CYP2C8, CYP2C9, and CYP2C19 (Uno et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the involvement of other P450s in these reactions might also account for lower correlation coefficients in cynomolgus monkeys; bufuralol 1Ј-hydroxylation is also catalyzed by CYP2C76 (Uno et al, 2011b) and CYP3A5 (Iwasaki et al, 2010). CYP2C76, not orthologous to any human P450, is partly responsible for differences in pitavastatin metabolism between cynomolgus monkeys and humans (Uno et al, 2010a). This information needs to be carefully considered when conducting drug metabolism studies using cynomolgus monkeys.…”

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confidence: 99%

Immunochemical Detection of Cytochrome P450 Enzymes in Liver Microsomes of 27 Cynomolgus Monkeys

Uehara¹,

Murayama²,

Nakanishi³

et al. 2011

J Pharmacol Exp Ther

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The cynomolgus monkey is widely used as a primate model in preclinical studies because of its evolutionary closeness to humans. Despite their importance in drug metabolism, the content of each cytochrome P450 (P450) enzyme has not been systematically determined in cynomolgus monkey livers. In this study, liver microsomes of 27 cynomolgus monkeys were analyzed by immunoblotting using selective P450 antibodies. The specificity of each antibody was confirmed by analyzing the cross-reactivity against 19 CYP1-3 subfamily enzymes using recombinant proteins. CYP2A, CYP2B6, CYP2C9/19, CYP2C76, CYP2D, CYP2E, CYP3A4, and CYP3A5 were detected in all 27 animals. In contrast, CYP1A, CYP1D, and CYP2J were below detectable levels in all liver samples. The average content of each P450 showed that among the P450s analyzed CYP3A (3A4 and 3A5) was the most abundant (40% of total immunoquantified P450), followed by CYP2A (25%), CYP2C (14%), CYP2B6 (13%), CYP2E1 (11%), and CYP2D (3%). No apparent sex differences were found for any P450. Interanimal variations ranged from 2.6-fold (CYP3A) to 11-fold (CYP2C9/19), and most P450s (CYP2A, CYP2D, CYP2E, CYP3A4, and CYP3A5) varied 3-to 4-fold. To examine the correlations of P450 content with enzyme activities, metabolic assays were performed in 27 cynomolgus monkey livers using 7-ethoxyresorufin, coumarin, pentoxyresorufin, flurbiprofen, bufuralol, dextromethorphan, and midazolam. CYP2D and CYP3A4 contents were significantly correlated with typical reactions of human CYP2D (bufuralol 1Ј-hydroxylation and dextromethorphan Odeethylation) and CYP3A (midazolam 1Ј-hydroxylation and 4-hydroxylation). The results presented in this study provide useful information for drug metabolism studies using cynomolgus monkeys.

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“…A number of cytochrome P450 (P450) enzymes have been identified and characterized in cynomolgus macaque, leading to the notion that the molecular properties of P450 enzymes in the cynomolgus macaque and humans are generally similar (Uno et al, 2011). The exception is CYP2C76, which is not orthologous to any human P450 and is partly responsible for species differences in drug metabolism between the cynomolgus macaque and humans (Uno et al, 2010). Therefore, characterization of drug-metabolizing enzymes corresponding to those essential for drug metabolism in human helps to better understand the similarities and differences of drug metabolism between model animals and humans.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Microsomal GlutathioneS-Transferases MGST1, MGST2, and MGST3 in Cynomolgus Macaque

et al. 2013

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The glutathione S-transferase (GST) family comprises cytosolic, mitochondrial, and microsomal GSTs, all essential enzymes that metabolize a wide range of endogenous and exogenous substrates. Among the microsomal GSTs (MGSTs) in humans, MGST1, MGST2, and MGST3 are involved in detoxification; however, MGSTs have not been fully investigated in cynomolgus macaque, an important primate species widely used in drug metabolism and toxicity studies. In the present study, cynomolgus MGST2 and MGST3 cDNAs were isolated from liver tissue and characterized along with previously isolated cynomolgus MGST1. For comparison with the cynomolgus cDNAs, MGST2 and MGST3 cDNAs were also isolated from rhesus macaque (closely related to cynomolgus macaque) liver. Cynomolgus MGST2 and MGST3, respectively, were highly identical (99 and 98%) to human MGST2 and MGST3 and nearly identical to the amino acid sequences of the rhesus orthologs, and they were closely clustered with human MGST2 and MGST3 by phylogenetic analysis. The analysis of genome data indicated that MGST1, MGST2, and MGST3, respectively, had similar gene structures and genomic organization in macaque and human. Therefore, cynomolgus MGSTs have molecular similarities to the corresponding human MGSTs. Cynomolgus MGST2 and MGST3 were expressed in liver, jejunum, and kidney, but at lower levels than MGST1. GST activities were measured with 1-chloro-2,4-dinitrobenzene and 1,2-epoxy-3-(p-nitrophenoxy)propane as substrates, using proteins heterologously expressed in Escherichia coli. Cynomolgus MGST1, MGST2, and MGST3 conjugated 1-chloro-2,4-dinitrobenzene and 1,2-epoxy-3-(p-nitrophenoxy)propane, indicating that cynomolgus MGST1, MGST2, and MGST3 are functional enzymes. These results suggest that these functional cynomolgus MGST enzymes and the corresponding human MGSTs are molecularly similar.

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Macaque CYP2C76 Encodes Cytochrome P450 Enzyme Not Orthologous to Any Human Isozymes

Cited by 28 publications

References 51 publications

Evaluation of 89 Compounds for Identification of Substrates for Cynomolgus Monkey CYP2C76, a New Bupropion/Nifedipine Oxidase

Evaluation of 89 Compounds for Identification of Substrates for Cynomolgus Monkey CYP2C76, a New Bupropion/Nifedipine Oxidase

Immunochemical Detection of Cytochrome P450 Enzymes in Liver Microsomes of 27 Cynomolgus Monkeys

Characterization of Microsomal GlutathioneS-Transferases MGST1, MGST2, and MGST3 in Cynomolgus Macaque

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