Blocking Wnt/LRP5 signaling by a soluble receptor modulates the epithelial to mesenchymal transition and suppresses met and metalloproteinases in osteosarcoma Saos-2 cells

J Orthop Res. 2007 Jul;25(7):964-71. doi: 10.1002/jor.20356.

Abstract

We previously reported the Wnt receptor low-density lipoprotein receptor-related protein 5 (LRP5) was frequently expressed in osteosarcoma (OS) tissue and correlated with metastasis and a lower disease-free survival. Subsequent in vitro analysis revealed that dominant-negative, soluble LRP5 (sLRP5) can reduce in vitro cellular invasion. In the current study, we examined the molecular mechanisms of blocking canonical Wnt signaling by sLRP5 in Saos-2 osteosarcoma cells. Transfection of sLRP5 caused a marked up-regulation of E-cadherin in this cell line. This increase in E-cadherin, seen primarily at the cell-cell contact borders, was associated with down-regulation of Slug and Twist, transcriptional repressors which mediate cancer invasion and metastasis. In contrast, N-cadherin, a mesenchymal marker, was reduced by sLRP5. In addition, blocking Wnt signaling by sLRP5 modulated other epithelial and mesenchymal markers (keratin 8 and 18, fibronectin), suggesting a reversal of epithelial-mesenchymal transition (EMT) seen during cancer progression. SLRP5 also reduced the expression of matrix metalloproteinase (MMP) 2 and 14, consistent with a decrease in invasive capacity. SLRP5 transfection decreased both Met expression and hepatocyte growth factor (HGF)-induced cell motility. Taken together, these results support a role for Wnt/LRP5 signaling in invasiveness of a subset of OS cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers, Tumor / metabolism
  • Bone Neoplasms / pathology
  • Cadherins / metabolism
  • Cell Line, Tumor
  • Cell Movement
  • Cell Transformation, Neoplastic
  • Disease Progression
  • Epithelial Cells / metabolism*
  • Epithelial Cells / pathology
  • Gene Silencing
  • Humans
  • LDL-Receptor Related Proteins / antagonists & inhibitors
  • LDL-Receptor Related Proteins / genetics
  • LDL-Receptor Related Proteins / metabolism*
  • Low Density Lipoprotein Receptor-Related Protein-5
  • Matrix Metalloproteinase 14
  • Matrix Metalloproteinase 2
  • Mesoderm / metabolism*
  • Mesoderm / pathology
  • Metalloproteases / genetics
  • Metalloproteases / metabolism*
  • Osteoblasts / metabolism*
  • Osteoblasts / pathology
  • Osteosarcoma / pathology
  • Proto-Oncogene Proteins / antagonists & inhibitors
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-met
  • Receptors, Growth Factor / antagonists & inhibitors
  • Receptors, Growth Factor / genetics
  • Receptors, Growth Factor / metabolism*
  • Signal Transduction
  • Transfection
  • Wnt Proteins / antagonists & inhibitors
  • Wnt Proteins / metabolism*

Substances

  • Biomarkers, Tumor
  • Cadherins
  • LDL-Receptor Related Proteins
  • LRP5 protein, human
  • Low Density Lipoprotein Receptor-Related Protein-5
  • Proto-Oncogene Proteins
  • Receptors, Growth Factor
  • Wnt Proteins
  • MET protein, human
  • Proto-Oncogene Proteins c-met
  • Metalloproteases
  • Matrix Metalloproteinase 2
  • Matrix Metalloproteinase 14