title: The ability of hydroxylated estrogens (2-OH-E2 and 4-OH-E2) to increase of SHBG gene, protein expression and intracellular levels in MCF-7 cells line.
abstract: OBJECTIVE
  Sex Hormone-Binding Globulin (SHBG) - specific carrier for sex steroids - regulates hormone bioavailable fraction and estrogen signaling system in breast cancer cells. This study was conducted to elucidate the effects of hydroxylated estrogen (E2) metabolites (2-OH-E2 and 4-OH-E2) on sex hormone binding globulin (SHBG) mRNA and protein expression as well as on intracellular and extracellular SHBG levels.
  
  
  METHODS
  MCF-7 human breast cancer cells were cultured with 2-OH-E2 or 4-OH-E2 in concentration of 1, 10 and 100 nM for 24 h, 17β-estradiol being used as a positive control. SHBG levels were measured in medium and cells by ELISA, SHBG mRNA expression was evaluated by real-time-PCR and protein expression by Western blot analysis.
  
  
  RESULTS
  4-OH-E2 in high doses and 2-OH-E2 in the highest dose, while 17β-estradiol in all doses used increased intracellular but not extracellular SHBG levels. Both metabolites increased SHBG mRNA expression, the rank order of potency being E2 > 4-OH-E2 > 2-OH-E2. Both E2 and its metabolites increased SHBG protein expression.
  
  
  CONCLUSIONS
  Although the metabolites showed a lower potency than 17β-estradiol, further studies are needed to clarify whether hydroxylated metabolites of E2 are potent ligands for SHBG.
authors.affiliation: Department of Physiology and Toxicology of Reproduction, Institute of Zoology, Jagiellonian University, 30-060 Kraków, Ingardena 6, Poland. ewa.gregoraszczuk@uj.edu.pl
authors.forename: E L
authors.initials: EL
authors.lastname: Gregoraszczuk
authors.forename: A
authors.initials: A
authors.lastname: Ptak
authors.forename: A
authors.initials: A
authors.lastname: Wrobel
mesh_terms: D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism*; D045744:Cell Line, Tumor; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D002393:Estrogens, Catechol; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012738:Sex Hormone-Binding Globulin / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D002393:Estrogens, Catechol; D012333:RNA, Messenger; D012738:Sex Hormone-Binding Globulin; D004958:Estradiol; C001390:2-hydroxyestradiol; C014036:4-hydroxyestradiol