Conversion of dehydroepiandrosterone sulfate at physiological plasma concentration into estrogens in MCF-7 cells.
Metabolism of dehydroepiandrosterone (DHEA), its sulfate (DHEAS), and androstene-3,17-dione (delta(4)) was performed at their physiological plasma concentrations in MCF-7 cell cultures (1 microM, 10 and 2 nM, respectively). Final metabolic products of these steroids were separated by HPLC-radioactive flow detection and identified by LC/MS or MS/MS. Typical and specific mass fragmentation spectra identified the presence of estrone (E(1)), 17beta-estradiol (E(2)), delta(4), DHEA, 5-androstene-3beta,17beta-diol (delta(5)), and testosterone as principal DHEAS metabolites. Other steroids, such as androstenedione, androsterone, and DHEA fatty acid esters at very low concentrations (from pM to nM), were also obtained after steroid incubation. This highly specific method allowed us to conclude whether a metabolite and enzymatic activity of interest were present in MCF-7 cells or not. We also showed that DHEAS at its physiological plasma concentration may be converted into estrogens and estrogen-like compounds in breast cancer cells. The estrogenic action of DHEAS on breast cancer cells was also measured by bioluminescence in a stably transfected human breast cancer MCF-7 cell line with a reporter gene that allowed expression of the firefly luciferase enzyme under the control of an estrogen regulatory element.
Le Bail
J C
JC
Laboratoire de Biochimie, University of Pharmacy of Limoges, UPRES EA 1085, 2 rue du Docteur Marcland, Limoges 87025 Cedex, France.
Lotfi
H
H
Charles
L
L
Pépin
D
D
Habrioux
G
G
D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002455:Cell Division; D003687:Dehydroepiandrosterone / Q000378:metabolism; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D004967:Estrogens / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter / Q000235:genetics; D013058:Mass Spectrometry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D004967:Estrogens; D003687:Dehydroepiandrosterone; D019314:Dehydroepiandrosterone Sulfate