Formation pathways of gamma-butyrolactone from the furan ring of tegafur during its conversion to 5-fluorouracil.
Drug Metab Dispos
; 38(8): 1267-76, 2010 Aug.
Article
em En
| MEDLINE
| ID: mdl-20463005
ABSTRACT
Tegafur (FT) is a 5-fluorouracil (5-FU) prodrug that has been clinically used for various cancer chemotherapies. The following metabolites of FT were identified in patients 5-FU, fluoro-beta-alanine, and gamma-butyrolactone (GBL) and its acidic form, gamma-hydroxybutyrate (GHB). GBL/GHB, which is probably generated from the furan ring of FT, inhibits tumor cell angiogenesis, contributing to the antitumor effect of FT-based therapies. In the present study, we identified the metabolites formed from the furan ring of FT by CYP2A6 and thymidine phosphorylase (TPase) using 2,4-dinitrophenylhydrazine derivatization procedures and clarified the metabolic pathway of FT to GBL/GHB. Succinaldehyde (SA) and 4-hydroxybutanal (4-OH-BTL) were produced as the metabolites because of the cleavage of the furan ring of FT during its conversion to 5-FU in cDNA-expressed CYP2A6 and purified TPase, respectively; however, GBL/GHB was hardly detected in cDNA-expressed CYP2A6 and purified TPase. GBL/GHB was formed after human hepatic microsomes or cDNA-expressed CYP2A6 mixed with cytosol were incubated with FT. Furthermore, 4-OH-BTL was converted to GBL/GHB in the microsomes and cytosol. These results suggest that GBL/GHB is generated from FT through the formation of SA and 4-OH-BTL but not directly from FT. Furthermore, the amount of 5-FU and GBL/GHB formed in the hepatic S9 was markedly decreased in the presence of a CYP2A6 inhibitor, suggesting that GBL/GHB may be mainly generated through the CYP2A6-mediated formation of SA.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
4-Butirolactona
/
Tegafur
/
Fluoruracila
/
Furanos
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
Drug Metab Dispos
Assunto da revista:
FARMACOLOGIA
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Japão
País de publicação:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA