Cytochromes P450 reconstituted with NADPH: P450 reductase mimic the activating and detoxicating metabolism of the anticancer drug ellipticine in microsomes
Language English Country Sweden Media print
Document type Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't
PubMed
17159771
PII: NEL270806A03
Knihovny.cz E-resources
- MeSH
- DNA Adducts metabolism MeSH
- Antineoplastic Agents pharmacokinetics MeSH
- Models, Biological MeSH
- Ellipticines pharmacokinetics MeSH
- Metabolic Detoxication, Phase I * MeSH
- Microsomes, Liver chemistry metabolism MeSH
- Rabbits MeSH
- Rats MeSH
- NADP chemistry metabolism MeSH
- NADPH-Ferrihemoprotein Reductase isolation & purification metabolism MeSH
- Cytochrome P-450 Enzyme System chemistry isolation & purification metabolism MeSH
- Animals MeSH
- Check Tag
- Rabbits MeSH
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Evaluation Study MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- DNA Adducts MeSH
- Antineoplastic Agents MeSH
- Ellipticines MeSH
- ellipticine MeSH Browser
- NADP MeSH
- NADPH-Ferrihemoprotein Reductase MeSH
- Cytochrome P-450 Enzyme System MeSH
OBJECTIVES: Ellipticine is a potent antineoplastic agent exhibiting multiple action mechanisms. Recently, we found that after cytochrome P450 (CYP)-mediated oxidation ellipticine forms covalent DNA adducts. Ellipticine oxidation by isolated CYP and its binding to DNA is the target of this study. METHODS: High performance liquid chromatography (HPLC) was employed for separation and characterization of ellipticine metabolites generated by CYPs. The (32)P-postlabeling technique was utilized to determine ellipticine-DNA adducts. RESULTS: Purified CYP enzymes reconstituted with NADPH:CYP reductase oxidized ellipticine to up to five metabolites, 7-hydroxy-, 9-hydroxy-, 12-hydroxy-, 13-hydroxyellipticine and ellipticine N(2)-oxide. However, only CYP1A1 was capable to form all metabolites. Using the reconstituted enzymatic system, we demonstrated that the detoxication ellipticine metabolites, 7-hydroxyellipticine and 9-hydroxyellipticine, are mainly generated by CYP1A1 and 1A2, while those responsible for DNA binding, 13-hydroxy-, 12-hydroxyellipticine and ellipticine N(2)-oxide, by CYP3A1 and 2C3. Likewise, the most efficient CYPs forming DNA adducts from ellipticine were CYP3A1 and 2C3. CONCLUSIONS: The results showed that the system of purified CYPs reconstituted with NADPH: CYP reductase proved for ellipticine oxidation provide a true reflection of the situation in the microsomal membrane.
