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Effect of human glutathione S-transferases on glutathione-dependent inactivation of cytochrome P450-dependent reactive intermediates of diclofenac.
Chem Res Toxicol. 2013 Nov 18; 26(11):1632-41.CR

Abstract

Idiosyncratic adverse drug reactions due to the anti-inflammatory drug diclofenac have been proposed to be caused by the generation of reactive acyl glucuronides and oxidative metabolites. For the oxidative metabolism of diclofenac by cytochromes P450 at least five different reactive intermediates have been proposed previously based on structural identification of their corresponding GSH-conjugates. In the present study, the ability of four human glutathione S-transferases (hGSTs) to catalyze the GSH-conjugation of the different reactive intermediates formed by P450s was investigated. Addition of pooled human liver cytosol and recombinant hGSTA1-1, hGSTM1-1, and hGSTP1-1 to incubations of diclofenac with human liver microsomes or purified CYP102A1M11 L437N as a model system significantly increased total GSH-conjugation. The strongest increase of total GSH-conjugation was observed by adding hGSTP1-1, whereas hGSTM1-1 and hGSTA1-1 showed lower activity. Addition of hGSTT1-1 only showed a minor effect. When considering the effects of hGSTs on GSH-conjugation of the different quinoneimines of diclofenac, it was found that hGSTP1-1 showed the highest activity in GSH-conjugation of the quinoneimine derived from 5-hydroxydiclofenac (5-OH-DF). hGSTM1-1 showed the highest activity in inactivation of the quinoneimine derived from 4'-hydroxydiclofenac (4'-OH-DF). Separate incubations with 5-OH-DF and 4'-OH-DF as substrates confirmed these results. hGSTs also catalyzed GSH-conjugation of the o-iminemethide formed by oxidative decarboxylation of diclofenac as well as the substitution of one of the chlorine atoms of DF by GSH. hGSTP1-1 showed the highest activity for the formation of these minor GSH-conjugates. These results suggest that hGSTs may play an important role in the inactivation of DF quinoneimines and its minor reactive intermediates especially in stress conditions when tissue levels of GSH are decreased.

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Publisher Full Text (DOI)

Authors+Show Affiliations

Dragovic S
Division of Molecular Toxicology, Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty of Sciences, VU University Amsterdam , De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
Boerma JS
No affiliation info available
Vermeulen NP
No affiliation info available
Commandeur JN
No affiliation info available

MeSH

Anti-Inflammatory Agents, Non-SteroidalBiocatalysisCytochrome P-450 Enzyme SystemDiclofenacGlutathioneGlutathione TransferaseHumansMicrosomes, LiverMutationOxidation-ReductionRecombinant ProteinsTandem Mass Spectrometry

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

24083800

Citation

Dragovic, Sanja, et al. "Effect of Human Glutathione S-transferases On Glutathione-dependent Inactivation of Cytochrome P450-dependent Reactive Intermediates of Diclofenac." Chemical Research in Toxicology, vol. 26, no. 11, 2013, pp. 1632-41.
Dragovic S, Boerma JS, Vermeulen NP, et al. Effect of human glutathione S-transferases on glutathione-dependent inactivation of cytochrome P450-dependent reactive intermediates of diclofenac. Chem Res Toxicol. 2013;26(11):1632-41.
Dragovic, S., Boerma, J. S., Vermeulen, N. P., & Commandeur, J. N. (2013). Effect of human glutathione S-transferases on glutathione-dependent inactivation of cytochrome P450-dependent reactive intermediates of diclofenac. Chemical Research in Toxicology, 26(11), 1632-41. https://doi.org/10.1021/tx400204d
Dragovic S, et al. Effect of Human Glutathione S-transferases On Glutathione-dependent Inactivation of Cytochrome P450-dependent Reactive Intermediates of Diclofenac. Chem Res Toxicol. 2013 Nov 18;26(11):1632-41. PubMed PMID: 24083800.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effect of human glutathione S-transferases on glutathione-dependent inactivation of cytochrome P450-dependent reactive intermediates of diclofenac. AU - Dragovic,Sanja, AU - Boerma,Jan Simon, AU - Vermeulen,Nico P E, AU - Commandeur,Jan N M, Y1 - 2013/11/05/ PY - 2013/10/3/entrez PY - 2013/10/3/pubmed PY - 2014/6/18/medline SP - 1632 EP - 41 JF - Chemical research in toxicology JO - Chem Res Toxicol VL - 26 IS - 11 N2 - Idiosyncratic adverse drug reactions due to the anti-inflammatory drug diclofenac have been proposed to be caused by the generation of reactive acyl glucuronides and oxidative metabolites. For the oxidative metabolism of diclofenac by cytochromes P450 at least five different reactive intermediates have been proposed previously based on structural identification of their corresponding GSH-conjugates. In the present study, the ability of four human glutathione S-transferases (hGSTs) to catalyze the GSH-conjugation of the different reactive intermediates formed by P450s was investigated. Addition of pooled human liver cytosol and recombinant hGSTA1-1, hGSTM1-1, and hGSTP1-1 to incubations of diclofenac with human liver microsomes or purified CYP102A1M11 L437N as a model system significantly increased total GSH-conjugation. The strongest increase of total GSH-conjugation was observed by adding hGSTP1-1, whereas hGSTM1-1 and hGSTA1-1 showed lower activity. Addition of hGSTT1-1 only showed a minor effect. When considering the effects of hGSTs on GSH-conjugation of the different quinoneimines of diclofenac, it was found that hGSTP1-1 showed the highest activity in GSH-conjugation of the quinoneimine derived from 5-hydroxydiclofenac (5-OH-DF). hGSTM1-1 showed the highest activity in inactivation of the quinoneimine derived from 4'-hydroxydiclofenac (4'-OH-DF). Separate incubations with 5-OH-DF and 4'-OH-DF as substrates confirmed these results. hGSTs also catalyzed GSH-conjugation of the o-iminemethide formed by oxidative decarboxylation of diclofenac as well as the substitution of one of the chlorine atoms of DF by GSH. hGSTP1-1 showed the highest activity for the formation of these minor GSH-conjugates. These results suggest that hGSTs may play an important role in the inactivation of DF quinoneimines and its minor reactive intermediates especially in stress conditions when tissue levels of GSH are decreased. SN - 1520-5010 UR - https://www.unboundmedicine.com/medline/citation/24083800/Effect_of_human_glutathione_S_transferases_on_glutathione_dependent_inactivation_of_cytochrome_P450_dependent_reactive_intermediates_of_diclofenac_ L2 - https://doi.org/10.1021/tx400204d DB - PRIME DP - Unbound Medicine ER -