title: Estrogen-mediated angiogenesis in thyroid tumor microenvironment is mediated through VEGF signaling pathways.
abstract: OBJECTIVE
  To explore the induction of a proangiogenic phenotype in endothelial cells in the thyroid tumor microenvironment by estrogen-treated thyroid cancer cells and to define the role of vascular endothelial growth factor (VEGF) in this interaction.
  
  
  METHODS
  Cell-based in vitro systems analysis.
  
  
  METHODS
  Thyroid tumor cell lines (BCPAP [papillary thyroid cancer] and ML-1 [follicular thyroid cancer]) were cultured with estradiol with and without an estrogen receptor (ER) inhibitor (fulvestrant or ICI) and used to treat human umbilical vein endothelial cells (HUVECs).
  
  
  METHODS
  Immunofluorescence was used to confirm the presence of ERα and ERβ in BCPAP cells. Conditioned medium was then used to evaluate the induction of HUVEC tubulogenesis and migration. Secretion of VEGF in this medium was evaluated by Western blot analysis. The expression of phosphoinositide 3-kinase (PI3K), the initiator of a proangiogenic pathway, was evaluated with Western blot analysis of HUVEC lysates. The subsequent effects of an ER inhibitor (fulvestrant/ICI) and a neutralizing VEGF antibody were also observed.
  
  
  RESULTS
  Estrogen receptor α and ERβ are expressed in thyroid cancer cells. Estrogen-stimulated ML-1 cells secreted an increased amount of VEGF likely as a result of ER signaling. In contact with this environment, HUVECs demonstrate enhanced tubulogenesis and migration. Western blot analysis documented estrogen-mediated upregulation of PI3K in HUVECs. These effects were mitigated by an ER inhibitor (fulvestrant/ICI) and a neutralizing VEGF antibody.
  
  
  CONCLUSIONS
  Our data provide evidence that estrogen can induce a proangiogenic endothelial cell phenotype in the thyroid tumor microenvironment through ER and VEGF signaling. Our findings suggest that the effect of antiestrogenic therapy targeting tumor angiogenesis can be enhanced through VEGF inhibition.
authors: Department of Otolaryngology, New York Eye and Ear Infirmary, 310 E 14th Steeet, New York, NY 10003, USA. akamat@nyee.edu
authors: Ameet
authors: A
authors: Kamat
authors: Shilpi
authors: S
authors: Rajoria
authors: Andrea
authors: A
authors: George
authors: Robert
authors: R
authors: Suriano
authors: Arulkumaran
authors: A
authors: Shanmugam
authors: Uchechukwu
authors: U
authors: Megwalu
authors: Pradeep Bangalore
authors: PB
authors: Prakash
authors: Raj
authors: R
authors: Tiwari
authors: Stimson
authors: S
authors: Schantz
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D004273:DNA, Neoplasm / Q000235:genetics*; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D004967:Estrogens / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009389:Neovascularization, Pathologic / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D004273:DNA, Neoplasm; D004967:Estrogens; D042461:Vascular Endothelial Growth Factor A