title: [Effects of exogenous ER beta expression on the cell growth properties of MCF-7 breast cancer cell line].
abstract: OBJECTIVE
  To study the effects of exogenous ER beta on the growth of breast cancer MCF-7 cells under different treatment.
  
  
  METHODS
  An eukaryotic expression vector containing 1.6 kb of human entire coding sequence of ER beta (pCDNA3-ER beta) was transfected into human breast cancer MCF-7 cells using lipofectamine 2000. The biological activity of ER beta was detected with the luciferase reporter containing estrogen responsive element (ERE) and the expression of ER beta protein by Western blot. The growth properties of MCF-7, pCDNA 3-transfected MCF-7 and pCDNA 3-ER beta-transfected MCF-7 cells under different treatment, including E2 (17beta-estradiol) and 4-OHT (4-hydroxytamoxifen), were observed.
  
  
  RESULTS
  A stronger activation of the reporter by ER beta in the presence of E2 was observed in the pCDNA 3-ER beta-transfected MCF-7 cells than in the pCDNA 3-transfected MCF-7 and in MCF-7 cells. Western blot analysis showed that the protein level of ER beta in the pCDNA 3-ER beta-transfected MCF-7 cells was markedly increased. Exogenous ER beta expression did not change the growth properties and the morphology of MCF-7 cells under normal condition. The pCDNA 3-ER beta-transfected MCF-7 cells proliferated at the same rate as naive cells in the presence of 4-OHT, whereas a strong inhibition of the proliferation of the pCDNA 3-ER beta-transfected MCF-7 cells in the presence of E2 was observed.
  
  
  CONCLUSIONS
  Exogenous ER beta expression does not increase the resistance to 4-OHT, and a strong inhibition of the proliferation may occur in the presence of E2.
authors.affiliation: Beijing Institute of Biotechnology, Beijing 100850, China.
authors.forename: Jian-hua
authors.initials: JH
authors.lastname: Zhu
authors.forename: Qi-nong
authors.initials: QN
authors.lastname: Ye
authors.forename: San-tai
authors.initials: ST
authors.lastname: Song
authors.forename: Ze-fei
authors.initials: ZF
authors.lastname: Jiang
authors.forename: Jing-hua
authors.initials: JH
authors.lastname: Yan
authors.forename: Chun-fang
authors.initials: CF
authors.lastname: Hao
authors.forename: Cui-fen
authors.initials: CF
authors.lastname: Huang
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology; D047629:Estrogen Receptor beta / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D013629:Tamoxifen / Q000031:analogs & derivatives / Q000494:pharmacology; D014162:Transfection
chemical_list: D004965:Estrogen Antagonists; D047629:Estrogen Receptor beta; D013629:Tamoxifen; C016601:afimoxifene; D004958:Estradiol