title: Identification of the major oxidative 3alpha-hydroxysteroid dehydrogenase in human prostate that converts 5alpha-androstane-3alpha,17beta-diol to 5alpha-dihydrotestosterone: a potential therapeutic target for androgen-dependent disease.
abstract: Androgen-dependent prostate diseases initially require 5alpha-dihydrotestosterone (DHT) for growth. The DHT product 5alpha-androstane-3alpha,17beta-diol (3alpha-diol), is inactive at the androgen receptor (AR), but induces prostate growth, suggesting that an oxidative 3alpha-hydroxysteroid dehydrogenase (HSD) exists. Candidate enzymes that posses 3alpha-HSD activity are type 3 3alpha-HSD (AKR1C2), 11-cis retinol dehydrogenase (RODH 5), L-3-hydroxyacyl coenzyme A dehydrogenase , RODH like 3alpha-HSD (RL-HSD), novel type of human microsomal 3alpha-HSD, and retinol dehydrogenase 4 (RODH 4). In mammalian transfection studies all enzymes except AKR1C2 oxidized 3alpha-diol back to DHT where RODH 5, RODH 4, and RL-HSD were the most efficient. AKR1C2 catalyzed the reduction of DHT to 3alpha-diol, suggesting that its role is to eliminate DHT. Steady-state kinetic parameters indicated that RODH 4 and RL-HSD were high-affinity, low-capacity enzymes whereas RODH 5 was a low-affinity, high-capacity enzyme. AR-dependent reporter gene assays showed that RL-HSD, RODH 5, and RODH 4 shifted the dose-response curve for 3alpha-diol a 100-fold, yielding EC(50) values of 2.5 x 10(-9) M, 1.5 x 10(-9) M, and 1.0 x 10(-9) M, respectively, when compared with the empty vector (EC(50) = 1.9 x 10(-7) M). Real-time RT-PCR indicated that L-3-hydroxyacyl coenzyme A dehydrogenase and RL-HSD were expressed more than 15-fold higher compared with the other candidate oxidative enzymes in human prostate and that RL-HSD and AR were colocalized in primary prostate stromal cells. The data show that the major oxidative 3alpha-HSD in normal human prostate is RL-HSD and may be a new therapeutic target for treating prostate diseases.
authors.affiliation: Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6084, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Bauman
authors.forename: Stephan
authors.initials: S
authors.lastname: Steckelbroeck
authors.forename: Michelle V
authors.initials: MV
authors.lastname: Williams
authors.forename: Donna M
authors.initials: DM
authors.lastname: Peehl
authors.forename: Trevor M
authors.initials: TM
authors.lastname: Penning
mesh_terms: D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific) / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000728:Androgens / Q000378:metabolism*; D015113:Androstane-3,17-diol / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D013196:Dihydrotestosterone / Q000378:metabolism*; D064429:Fatty Acid Synthases / Q000235:genetics; D006801:Humans; D008297:Male; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics; D011467:Prostate / Q000201:enzymology* / Q000378:metabolism; D011469:Prostatic Diseases / Q000188:drug therapy / Q000201:enzymology* / Q000378:metabolism; D011944:Receptors, Androgen / Q000235:genetics; D015533:Transcriptional Activation; D014162:Transfection
chemical_list: D000728:Androgens; D011944:Receptors, Androgen; D013196:Dihydrotestosterone; D015113:Androstane-3,17-diol; D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific); C036543:short chain trans-2-enoyl-CoA reductase; D009247:NADH, NADPH Oxidoreductases; D064429:Fatty Acid Synthases