Role of polymorphic human cytochrome P450 enzymes in estrone oxidation
| Autor: | M. Joy Knight, Dagny Dryer, Judy Guernsey, Alastair E. Cribb, Kimberly Hender, Marvin Tesch, Tarek M. Saleh |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Epidemiology
medicine.drug_class Estrone CYP1B1 Population Breast Neoplasms In Vitro Techniques Hydroxylation Sensitivity and Specificity Mixed Function Oxygenases chemistry.chemical_compound Cytochrome P-450 Enzyme System Cytochrome P-450 CYP1A2 medicine Biomarkers Tumor Cytochrome P-450 CYP1A1 Tumor Cells Cultured Humans education Chromatography High Pressure Liquid chemistry.chemical_classification education.field_of_study biology CYP1A2 Cytochrome P450 Enzyme Oncology chemistry Biochemistry Estrogen biology.protein Microsomes Liver Female Oxidation-Reduction |
| Zdroj: | Cancer epidemiology, biomarkersprevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology. 15(3) |
| ISSN: | 1055-9965 |
| Popis: | Estrogen and its metabolites are believed to play important roles in breast cancer. The influence of genetic polymorphisms in the enzymes responsible for formation and disposition of estrogen on breast cancer risk may shed light on the importance of estrogen metabolites in this disease. However, for such studies to be valid, it is important to correctly identify the enzymes involved in estrogen bioactivation. Therefore, we assessed the human cytochrome P450–dependent oxidation of estrone using substrate concentrations that more closely approximate the maximum expected concentrations in breast tissue. The in vitro metabolism of estrone by recombinant human cytochrome P450 enzymes and human liver microsomes was studied. The formation of estrone metabolites (2-hydroxyestrone, 4-hydroxyestrone, and 16α-hydroxyestrone) was monitored by high-performance liquid chromatography. 2-Hydroxyestrone formation was catalyzed predominantly by CYP1A2, CYP1A1, and CYP1B1 enzymes; 4-hydroxyestrone formation was catalyzed predominantly by CYP1B1, CYP1A2, and CYP1A1 enzymes; and 16α-hydroxyestrone formation was catalyzed predominantly by CYP2C19, CYP1A1, and CYP3A5. This study confirms the important role of members of the CYP1 family in the 2-hydroxylation and 4-hydroxylation of estrone, but the enzymes identified as responsible for the 16α-hydroxylation of estrone are different from those previously identified. The relative importance of these enzymes in vivo would depend on the specific tissue expression of the enzymes. These enzymes are all known to be genetically variant in the human population, and additional studies to assess the role CYP1A2, CYP2C19, and CYP3A5 in breast cancer risk are indicated. (Cancer Epidemiol Biomarkers Prev 2006;15(3):551–8) |
| Databáze: | OpenAIRE |
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