ReferenceID 3847

Interaction of adenanthin with glutathione and thiol enzymes: selectivity for thioredoxin reductase and inhibition of peroxiredoxin recycling

Free Radic Biol Med

The diterpenoid, adenanthin, represses tumor growth and prolongs survival in mouse promyelocytic leukemia models (Liu et al., Nat. Chem. Biol. 8, 486, 2012). It was proposed that this was done by inactivating peroxiredo

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Reference Id
3847
Evidence Id
20437
Core Evidence Id
20437
Source Reference Id
973
Herb2 Reference Id
HBREF001684
Subject Paper Key
HBIN014672_25289458
Pubmed Id
25289458
Doi
10.1016/j.freeradbiomed.2014.09.025
Paper Title
Interaction of adenanthin with glutathione and thiol enzymes: selectivity for thioredoxin reductase and inhibition of peroxiredoxin recycling
Paper Abstract
The diterpenoid, adenanthin, represses tumor growth and prolongs survival in mouse promyelocytic leukemia models (Liu et al., Nat. Chem. Biol. 8, 486, 2012). It was proposed that this was done by inactivating peroxiredoxins (Prxs) 1 and 2 through the formation of an adduct specifically on the resolving Cys residue. We confirmed that adenanthin underwent Michael addition to isolated Prx2, thereby inhibiting oxidation to a disulfide-linked dimer. However, contrary to the original report, both the peroxidatic and the resolving Cys residues could be derivatized. Glutathione also formed an adenanthin adduct, reacting with a second-order rate constant of 25±5 M(-1) s(-1). With 50 M adenanthin, the peroxidatic and resolving Cys of Prx2 reacted with half-times of 7 and 40 min, respectively, compared with 10 min for GSH. When erythrocytes or Jurkat T cells were treated with adenanthin, we saw no evidence for a reaction with Prxs 1 or 2. Instead, adenanthin caused time- and concentration-dependent loss of GSH followed by dimerization of the Prxs. Prxs undergo continuous oxidation in cells and are normally recycled by thioredoxin reductase and thioredoxin. Our results indicate that Prx reduction was inhibited. We observed rapid inhibition of purified thioredoxin reductase (half-time 5 min with 2 M adenanthin) and in cells, thioredoxin reductase was much more sensitive than GSH and loss of both preceded accumulation of oxidized Prxs. Thus, adenanthin is not a specific Prx inhibitor, and its reported antitumor and anti-inflammatory effects are more likely to involve more general inhibition of thioredoxin and/or glutathione redox pathways.
Journal
Free Radic Biol Med
Publish Year
2014
Experiment Subject
rythrocytes or jurkat t cells
Experiment Type
Cell Experiment
Phenotype Related
Paper Title Cn
Paper Title En
Interaction of adenanthin with glutathione and thiol enzymes: selectivity for thioredoxin reductase and inhibition of peroxiredoxin recycling
Bilingual Status
semi_complete