Evaluation of ligand selectivity using reporter cell lines stably expressing estrogen receptor alpha or beta.
Estrogens control transcriptional responses through binding to two different nuclear receptors, estrogen receptor alpha (ERalpha) and beta (ERbeta). Since these two ER subtypes are thought to mediate different biological effects, there is intense interest in designing subtype-selective ER ligands. In this study, we evaluated the ERalpha and ERbeta selectivity of 19 known estrogens and antiestrogens using reporter cell lines previously developed in our laboratory. The HELN-ERalpha and HELN-ERbeta cells stably express full-length ERalpha and ERbeta, respectively, and are derived from HELN cells (HeLa cells stably transfected with an ERE-driven luciferase plasmid). We report that 16alpha-LE2, PPT and 3beta,5alpha-GSD have a high ERalpha-selective agonist potency while 8beta-VE2, DPN, genistein and biochanin A show ERbeta selectivity with 8beta-VE2 being the most potent and selective ERbeta agonist. We also tested ER antagonists and we showed that raloxifene and RU486 are ERalpha and ERbeta-selective antiestrogens, respectively. In all cases, selectivity is due to differences in binding affinities as indicated by whole-cell ligand-binding assays. Very interestingly, we demonstrate that a combination of genistein and raloxifene produces a full-ERbeta specific response. Together these results demonstrate the usefulness of our stably transfected cell lines to characterize ER ligands and indicate that treatments combining agonist/antagonist ligands produce full-ERbeta selectivity.
INSERM, U540, Montpellier F-34090, France.
Aurélie
A
Escande
Arnaud
A
Pillon
Nadège
N
Servant
Jean-Pierre
JP
Cravedi
Fernando
F
Larrea
Peter
P
Muhn
Jean-Claude
JC
Nicolas
Vincent
V
Cavaillès
Patrick
P
Balaguer
D001665:Binding Sites; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D015195:Drug Design; D004965:Estrogen Antagonists / Q000145:classification / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047629:Estrogen Receptor beta / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004967:Estrogens / Q000145:classification / Q000494:pharmacology*; D017930:Genes, Reporter; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D020849:Raloxifene Hydrochloride / Q000494:pharmacology; D013329:Structure-Activity Relationship; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
D004965:Estrogen Antagonists; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D008024:Ligands; D020849:Raloxifene Hydrochloride; D008156:Luciferases