Upregulation of TrkB promotes epithelial-mesenchymal transition and anoikis resistance in endometrial carcinoma

PLoS One. 2013 Jul 30;8(7):e70616. doi: 10.1371/journal.pone.0070616. Print 2013.

Abstract

Mechanisms governing the metastasis of endometrial carcinoma (EC) are poorly defined. Recent data support a role for the cell surface receptor tyrosine kinase TrkB in the progression of several human tumors. Here we present evidence for a direct role of TrkB in human EC. Immunohistochemical analysis revealed that TrkB and its secreted ligand, brain-derived neurotrophic factor (BDNF), are more highly expressed in EC than in normal endometrium. High TrkB levels correlated with lymph node metastasis (p<0.05) and lymphovascular space involvement (p<0.05) in EC. Depletion of TrkB by stable shRNA-mediated knockdown decreased the migratory and invasive capacity of cancer cell lines in vitro and resulted in anoikis in suspended cells. Conversely, exogenous expression of TrkB increased cell migration and invasion and promoted anoikis resistance in suspension culture. Furthermore, over-expression of TrkB or stimulation by BDNF resulted in altered the expression of molecular mediators of the epithelial-to-mesenchymal transition (EMT). RNA interference (RNAi)-mediated depletion of the downstream regulator, Twist, blocked TrkB-induced EMT-like transformation. The use of in vivo models revealed decreased peritoneal dissemination in TrkB-depleted EC cells. Additionally, TrkB-depleted EC cells underwent mesenchymal-to-epithelial transition and anoikis in vivo. Our data support a novel function for TrkB in promoting EMT and resistance to anoikis. Thus, TrkB may constitute a potential therapeutic target in human EC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Animals
  • Anoikis / genetics*
  • Brain-Derived Neurotrophic Factor / pharmacology
  • Cell Line, Tumor
  • Cell Movement / genetics
  • Cell Proliferation
  • Cell Transformation, Neoplastic / genetics
  • Cell Transformation, Neoplastic / metabolism
  • Endometrial Neoplasms / genetics*
  • Endometrial Neoplasms / pathology
  • Enzyme Activation / drug effects
  • Epithelial-Mesenchymal Transition / genetics*
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Mice
  • Middle Aged
  • Neoplasm Grading
  • Neoplasm Staging
  • Receptor, trkB / antagonists & inhibitors
  • Receptor, trkB / genetics*
  • Receptor, trkB / metabolism
  • Tumor Burden
  • Tumor Cells, Cultured
  • Twist-Related Protein 1 / metabolism

Substances

  • Brain-Derived Neurotrophic Factor
  • Twist-Related Protein 1
  • Receptor, trkB

Grants and funding

This study was supported by the National Natural Science Foundation of China (no. 81072139, no. 81172476) and the Project of Science and Technology Commission of Shanghai Municipality (no. 12ZR1451400). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.