Journal article
Formation of tamoxifen-DNA adducts via O-sulfonation, not O-acetylation, of alpha-hydroxytamoxifen in rat and human livers
Drug metabolism and disposition, Vol.33(11), pp.1673-1678
11/2005
DOI: 10.1124/dmd.105.005330
PMID: 16099924
Abstract
Tamoxifen (TAM) is used as the standard endocrine therapy for breast cancer patients and as a chemopreventive agent for women at high risk for this disease. Unfortunately, treatment of TAM increases the incidence of endometrial cancer; this may be due to the genotoxic damage induced by TAM metabolites. Formation of TAM-DNA adducts in rat liver correlates with the development of hepatocarcinoma. TAM-DNA adducts are proposed to be formed through O-sulfonation and/or O-acetylation of alpha-hydroxylated TAM and its metabolites. However, the role of O-sulfonation and O-acetylation in the formation of TAM-DNA adducts has not been extensively investigated. Rat or human hydroxysteroid sulfotransferases (HST), acetyltransferases, and liver cytosol were incubated with calf thymus DNA, alpha-OHTAM, and either 3'-phosphoadenosine 5'-phosphosulfate (PAPS) or acetyl coenzyme A (acetyl-CoA) as a cofactor and analyzed for TAM-DNA adduct formation, using 32P postlableling/polyacrylamide gel electrophoresis analysis. TAM-DNA adduct was formed when PAPS, not acetyl-CoA, was used. No TAM-DNA adducts were produced using human N-acetyltransferase I and II. HST antibody inhibited approximately 90% of TAM-DNA adduct formation generated by the cytosol or HST, suggesting that HST is primarily involved in the formation of TAM-DNA adducts. The formation of TAM-DNA adducts with rat liver cytosol and HST was much higher than that of human liver cytosol and HST. Our results indicate that TAM-DNA adducts are formed via O-sulfonation, not O-acetylation, of alpha-hydroxylated TAM and its metabolites.
Details
- Title: Subtitle
- Formation of tamoxifen-DNA adducts via O-sulfonation, not O-acetylation, of alpha-hydroxytamoxifen in rat and human livers
- Creators
- Sung Yeon Kim - Stony Brook UniversityY R Santosh LaxmiNaomi SuzukiKenichiro OguraTadashi WatabeMichael W DuffelShinya Shibutani - Stony Brook University
- Resource Type
- Journal article
- Publication Details
- Drug metabolism and disposition, Vol.33(11), pp.1673-1678
- DOI
- 10.1124/dmd.105.005330
- PMID
- 16099924
- ISSN
- 0090-9556
- eISSN
- 1521-009X
- Grant note
- R01 CA038683 / NCI NIH HHS ES09418 / NIEHS NIH HHS CA38683 / NCI NIH HHS
- Language
- English
- Date published
- 11/2005
- Academic Unit
- Pharmaceutical Sciences and Experimental Therapeutics; Medicinal and Natural Products Chemistry
- Record Identifier
- 9984303286502771
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