A Predominate Role of CYP1A2 for the Metabolism of Nabumetone to the Active Metabolite, 6-Methoxy-2-naphthylacetic Acid, in Human Liver Microsomes

Turpeinen, Miia; Hofmann, Ute; Klein, Kathrin; Mürdter, Thomas E.; Schwab, Matthias; Zanger, Ulrich M.

doi:10.1124/dmd.108.025700

Cited by 43 publications

(27 citation statements)

References 32 publications

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“…2). The K m obtained was 47 mM, a value similar to the previously reported value of 45 mM (Turpeinen et al, 2009). …”

Section: Downloaded Fromsupporting

confidence: 76%

“…6). In contrast to the published results (Turpeinen et al, 2009), CYP2C19 and CYP2E1 did not reveal formation of 6-MNA, although they both show formation of significant amounts of 3-hydroxynabumetone (Fig. 6, inset).…”

Section: P450 Enzymes Involved In Conversion Of Nabumetone To 6-mnacontrasting

confidence: 55%

“…A previous study of the P450 isoform specificity of nabumetone oxidation surveyed a limited number of enzymes without examining the formation of reaction intermediates (Turpeinen et al, 2009). A broader panel of P450 enzymes was therefore tested for their possible involvement in nabumetone oxidation.…”

Section: P450 Enzymes Involved In Conversion Of Nabumetone To 6-mnamentioning

confidence: 99%

“…The relative activities of individual cytochrome P450 enzymes in the conversion of nabumetone to 6-MNA and studies of microsomes with inhibitors indicated that CYP1A2, which had the highest activity, accounted for more than 50% of the conversion, with smaller contributions by CYP2B6, CYP2C19, CYP2D6, and CYP2E1 (Turpeinen et al, 2009). However, the detailed mechanism of the cytochrome P450-catalyzed conversion of nabumetone to 6-MNA remains unknown.…”

Section: Introductionmentioning

confidence: 99%

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Carbon-Carbon Bond Cleavage in Activation of the Prodrug Nabumetone

et al. 2014

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Carbon-carbon bond cleavage reactions are catalyzed by, among others, lanosterol 14-demethylase (CYP51), cholesterol side-chain cleavage enzyme (CYP11), sterol 17b-lyase (CYP17), and aromatase (CYP19). Because of the high substrate specificities of these enzymes and the complex nature of their substrates, these reactions have been difficult to characterize. A CYP1A2-catalyzed carbon-carbon bond cleavage reaction is required for conversion of the prodrug nabumetone to its active form, 6-methoxy-2-naphthylacetic acid (6-MNA). Despite worldwide use of nabumetone as an anti-inflammatory agent, the mechanism of its carbon-carbon bond cleavage reaction remains obscure. With the help of authentic synthetic standards, we report here that the reaction involves 3-hydroxylation, carbon-carbon cleavage to the aldehyde, and oxidation of the aldehyde to the acid, all catalyzed by CYP1A2 or, less effectively, by other P450 enzymes. The data indicate that the carbon-carbon bond cleavage is mediated by the ferric peroxo anion rather than the ferryl species in the P450 catalytic cycle. CYP1A2 also catalyzes O-demethylation and alcohol to ketone transformations of nabumetone and its analogs.

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“…2). The K m obtained was 47 mM, a value similar to the previously reported value of 45 mM (Turpeinen et al, 2009). …”

Section: Downloaded Fromsupporting

confidence: 76%

Section: P450 Enzymes Involved In Conversion Of Nabumetone To 6-mnacontrasting

confidence: 55%

Section: P450 Enzymes Involved In Conversion Of Nabumetone To 6-mnamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Carbon-Carbon Bond Cleavage in Activation of the Prodrug Nabumetone

et al. 2014

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“…The P450 activity cocktail assay presented here is focused on the seven most important P450s as judged by their roles in the metabolism of clinically used drugs (Zanger et al, 2008). For CYP1A2 (phenacetin), CYP2B6 (bupropion), CYP2C8 (amodiaquine), CYP2C9 (tolbutamide), and CYP2C19 (S-mephenytoin), we used single established marker substrates (Richter et al, 2004;Walsky and Obach, 2004;Turpeinen et al, 2009) and combined them in a cocktail assay with substrates not used before for CYP2D6 (propafenone) and CYP3A4 (atorvastatin).…”

Section: Discussionmentioning

confidence: 99%

Profiling Induction of Cytochrome P450 Enzyme Activity by Statins Using a New Liquid Chromatography-Tandem Mass Spectrometry Cocktail Assay in Human Hepatocytes

Feidt¹,

Klein²,

Hofmann³

et al. 2010

Drug Metab Dispos

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ABSTRACT:Human hepatocytes in primary culture are a very useful model to directly assess induction of gene expression by xenobiotics. We developed a cytochrome P450 (P450) activity cocktail assay using model substrates for the seven important P450s 1A2 (phenacetin), 2B6 (bupropion), 2C8 (amodiaquine), 2C9 (tolbutamide), 2C19 (Smephenytoin), 2D6 (propafenone), and 3A4 (atorvastatin). Metabolite formation was determined by liquid chromatography-tandem mass spectrometry in hepatocyte culture supernatants. Atorvastatin has not been previously assessed as a CYP3A probe drug. We demonstrate highly selective atorvastatin ortho-hydroxylation by CYP3A4 by recombinant P450s. In human liver microsomes orthohydroxyatorvastatin formation was highly correlated with CYP3A4 protein content (r s ‫؍‬ 0.78, p < 0.0001, n ‫؍‬ 150). We profiled induction of these P450 activities in primary human hepatocytes after treatment with 30 M atorvastatin, lovastatin, pravastatin, rosuvastatin, and simvastatin for 24 to 72 h. Except for pravastatin, all statins induced P450 activities to various degrees, approximately in the order atorvastatin > simvastatin > lovastatin > rosuvastatin. Inducibility of P450s followed the order CYP2C8 > CYP3A4 > CYP2C9 > CYP2B6 > CYP2C19 ϳ CYP2D6 > CYP1A2. The strongest induction was observed for amodiaquine N-desalkylation, which was induced approximately 20-fold. Quantitative reverse transcription-polymerase chain reaction confirmed corresponding changes on the mRNA level with even more dramatic induction up to almost 100-fold. These data suggest a broader inducing effect of statins on cytochrome P450s and possibly other absorption, distribution, metabolism, and excretion genes than previously known, thus further emphasizing their drug-drug interaction potential. Our cocktail assay should be helpful for economical use of human hepatocytes in the assessment of P450 induction by drugs and drug candidates.

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Unusual Metabolic Reactions and Pathways

Guengerich

Isin

2014

Handbook of Metabolic Pathways of Xenobiotics

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A Predominate Role of CYP1A2 for the Metabolism of Nabumetone to the Active Metabolite, 6-Methoxy-2-naphthylacetic Acid, in Human Liver Microsomes

Cited by 43 publications

References 32 publications

Carbon-Carbon Bond Cleavage in Activation of the Prodrug Nabumetone

Carbon-Carbon Bond Cleavage in Activation of the Prodrug Nabumetone

Profiling Induction of Cytochrome P450 Enzyme Activity by Statins Using a New Liquid Chromatography-Tandem Mass Spectrometry Cocktail Assay in Human Hepatocytes

Unusual Metabolic Reactions and Pathways

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