title: The effect of transforming growth factor-beta on steroidogenesis and expression of key steroidogenic enzymes with a human ovarian thecal-like tumor cell model.
abstract: OBJECTIVE
  Our purpose was to determine the effects of transforming growth factor-beta on steroidogenesis and regulation of steroidogenic enzyme expression by use of a human ovarian thecal-like tumor cell culture system.
  
  
  METHODS
  Human ovarian thecal-like tumor cells were treated in serum-free medium in the presence or absence of forskolin and transforming growth factor-beta 1. The accumulation of progesterone and androstenedione in the culture medium was evaluated by radioimmunoassay. The effects of forskolin with or without transforming growth factor-beta 1 on the enzymatic activity of P450c17 and 3 beta HSD, the expression of immunodetectable P450c17 protein, and the expression of messenger ribonucleic acid for P450scc, P450c17, and 3 beta HSD were determined.
  
  
  RESULTS
  Basal steroid secretion, steroidogenic enzyme activity, enzyme protein, and messenger ribonucleic acid expression were not affected by transforming growth factor-beta 1 alone. Forskolin treatment significantly stimulated steroid production and the enzymatic activity of P450c17 and 3 beta HSD up to 10-fold above basal levels. However, transforming growth factor-beta 1 inhibited forskolin-stimulated androstenedione production to near basal levels and increased progesterone 1.4- to 2-fold while suppressing P450c17 enzyme activity to near basal levels, but it did not affect 3 beta HSD activity. Forskolin-stimulated immunodetectable P450c17 alpha protein was markedly inhibited by transforming growth factor-beta 1. In addition, transforming growth factor-beta 1 markedly inhibited the forskolin-stimulation of P450c17 messenger ribonucleic acid, while not significantly altering P450scc or 3 beta HSD messenger ribonucleic acid expression.
  
  
  CONCLUSIONS
  Forskolin stimulated human ovarian thecal-like tumor cell steroidogenesis, P450c17 and 3 beta HSD activity, immunodetectable P450c17, and messenger ribonucleic acid content for P450scc, P450c17, and 3 beta HSD. Transforming growth factor-beta 1 inhibited forskolin stimulation of androstenedione production through the inhibition of P450c17 expression.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, 75235-9032, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Carr
authors.forename: E A
authors.initials: EA
authors.lastname: McGee
authors.forename: C
authors.initials: C
authors.lastname: Sawetawan
authors.forename: C D
authors.initials: CD
authors.lastname: Clyne
authors.forename: W E
authors.initials: WE
authors.lastname: Rainey
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism; D000735:Androstenedione / Q000096:biosynthesis*; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D005260:Female; D015870:Gene Expression; D006801:Humans; D007700:Kinetics; D010051:Ovarian Neoplasms / Q000378:metabolism*; D011374:Progesterone / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000378:metabolism; D013254:Steroid 17-alpha-Hydroxylase / Q000235:genetics / Q000378:metabolism; D013798:Thecoma / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D005576:Colforsin; D000735:Androstenedione; D011374:Progesterone; D015096:3-Hydroxysteroid Dehydrogenases; D013254:Steroid 17-alpha-Hydroxylase; D002786:Cholesterol Side-Chain Cleavage Enzyme