Osteopontin as a key mediator for vasculogenic mimicry in hepatocellular carcinoma

Tohoku J Exp Med. 2011 May;224(1):29-39. doi: 10.1620/tjem.224.29.

Abstract

Osteopontin (OPN) is overexpressed in a variety of cancers including hepatocellular carcinoma (HCC), and is likely involved in the process of vasculogenic mimicry (VM) in some tumor cells. In this study, we explored whether OPN plays a role for VM in HCC. Metastatic MHCC97-H human HCC cells and non-metastatic Hep3B human HCC cells were compared for their abilities to establish VM. Three dimensional-culture assays showed that MHCC97-H cells but not Hep3B cells were able to form the chord-like structure that represents VM. Real-time RT-PCR arrays were used to detect gene expression profiles of the two HCC cell lines in three-dimensional culture. PCR array analyses revealed the increased expression of OPN in MHCC97-H cells forming VM compared with Hep3B cells. Small interfering RNA was employed to investigate whether OPN knockdown could influence VM, and the expression of matrix metalloproteinase (MMP)-2, MMP-9 and urokinase-type plasminogen activator (uPA) in MHCC97-H cells. OPN knockdown resulted in a significant decrease in the ability of MHCC97-H cells to form VM, which was accompanied by the down-regulation of MMP-2 and uPA expression. Furthermore, human HCC tissue samples were studied by immunohistochemistry to analyze the correlations between VM and the expression of OPN, MMP-2 and uPA. There existed significant positive correlations between VM and the expression of OPN, MMP-2 and uPA in HCC tissue samples. In conclusion, OPN is required for VM in HCC cells, and its action may be associated with activation of MMP-2 and uPA. OPN-targeted therapeutics may be useful for patients with advanced HCC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinoma, Hepatocellular / blood supply*
  • Carcinoma, Hepatocellular / metabolism
  • Cell Line, Tumor
  • DNA Primers / genetics
  • Gene Expression Profiling
  • Gene Knockdown Techniques
  • Humans
  • Immunohistochemistry
  • Liver Neoplasms / blood supply*
  • Liver Neoplasms / metabolism
  • Matrix Metalloproteinase 2 / metabolism
  • Matrix Metalloproteinase 9 / metabolism
  • Neovascularization, Pathologic / pathology
  • Osteopontin / metabolism*
  • RNA, Small Interfering / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Urokinase-Type Plasminogen Activator / metabolism

Substances

  • DNA Primers
  • RNA, Small Interfering
  • Osteopontin
  • Urokinase-Type Plasminogen Activator
  • Matrix Metalloproteinase 2
  • Matrix Metalloproteinase 9