title: Inhibitory effects of ERβ on proliferation, invasion, and tumor formation of MCF-7 breast cancer cells--prognostication for the use of ERβ-selective therapy.
abstract: BACKGROUND
  Estrogen is well-known as an important factor in the physiological functions and pathological processes of breast. Estrogen receptor β (ERβ) is expressed in the majority of breast cancers at lower levels compared with the normal breast tissue.
  
  
  OBJECTIVE
  The effect of ERβ on the characteristics of breast tumor cells and its prognostication for the use of ERβ-selective therapy were investigated here for the first time.
  
  
  METHODS
  ERβ was overexpressed in ERα positive MCF-7 breast cancer cells by gene transfection. The proliferation, motility, and xenografts growth of MCF-7 cells were investigated by MTT assays, wound-healing assay and animal study.
  
  
  RESULTS
  Results demonstrated that ERβ-GFP localized in both the cytoplasm and the nucleus in the presence of 17β-estradiol (E2), with stronger fluorescence-signal intensity in the nucleus, 2.8-times higher than that in the cytoplasm. The ERβ overexpressed MCF-7 cells resulted in a 38.7% decreased growth rate and motility in vitro. Furthermore, ERβ overexpression enhanced the antiproliferative effects of phytoestrogen, antiestrogen, and histone deacetylase inhibitor. Exogenous ERβ expression reduced tumor volume by 99% at 27 days postadministration, indicated that overexpression of ERβ led to retardation of tumor formation and growth in immunodeficient mice.
  
  
  CONCLUSIONS
  This study provided a relatively new evidence to support that ERβ is an important modulator of proliferation and motility of breast cancer cells, and implied for the first time a possibility for the use of novel ERβ-selective therapies in breast cancer treatment.
authors.affiliation: Department of Biomedical Engineering, School of Life Science and Technology, China Pharmaceutical University, Nanjing, PR China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Zhenzhen
authors.initials: Z
authors.lastname: Tu
authors.forename: Lianxiao
authors.initials: L
authors.lastname: An
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Qian
authors.forename: Samuel
authors.initials: S
authors.lastname: Achilefu
authors.forename: Yueqing
authors.initials: Y
authors.lastname: Gu
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D047629:Estrogen Receptor beta / Q000008:administration & dosage / Q000502:physiology* / Q000627:therapeutic use; D019317:Evidence-Based Medicine / Q000379:methods; D005260:Female; D006131:Growth Inhibitors / Q000008:administration & dosage / Q000502:physiology* / Q000627:therapeutic use; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009361:Neoplasm Invasiveness / Q000473:pathology / Q000517:prevention & control; D011379:Prognosis; D023041:Xenograft Model Antitumor Assays / Q000379:methods
chemical_list: D047629:Estrogen Receptor beta; D006131:Growth Inhibitors