Inhibition of tumor vasculogenic mimicry and prolongation of host survival in highly aggressive gallbladder cancers by norcantharidin via blocking the ephrin type a receptor 2/focal adhesion kinase/paxillin signaling pathway

PLoS One. 2014 May 8;9(5):e96982. doi: 10.1371/journal.pone.0096982. eCollection 2014.

Abstract

Vasculogenic mimicry (VM) is a newly-defined tumor microcirculation pattern in highly aggressive malignant tumors. We recently reported tumor growth and VM formation of gallbladder cancers through the contribution of the ephrin type a receptor 2 (EphA2)/focal adhesion kinase (FAK)/Paxillin signaling pathways. In this study, we further investigated the anti-VM activity of norcantharidin (NCTD) as a VM inhibitor for gallbladder cancers and the underlying mechanisms. In vivo and in vitro experiments to determine the effects of NCTD on tumor growth, host survival, VM formation of GBC-SD nude mouse xenografts, and vasculogenic-like networks, malignant phenotypes i.e., proliferation, apoptosis, invasion and migration of GBC-SD cells. Expression of VM signaling-related markers EphA2, FAK and Paxillin in vivo and in vitro were examined by immunofluorescence, western blotting and real-time polymerase chain reaction (RT-PCR), respectively. The results showed that after treatment with NCTD, GBC-SD cells were unable to form VM structures when injecting into nude mouse, growth of the xenograft was inhibited and these observations were confirmed by facts that VM formation by three-dimensional (3-D) matrix, proliferation, apoptosis, invasion, migration of GBC-SD cells were affected; and survival time of the xenograft mice was prolonged. Furthermore, expression of EphA2, FAK and Paxillin proteins/mRNAs of the xenografts was downregulated. Thus, we concluded that NCTD has potential anti-VM activity against human gallbladder cancers; one of the underlying mechanisms may be via blocking the EphA2/FAK/Paxillin signaling pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Antineoplastic Agents / therapeutic use
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology*
  • Bridged Bicyclo Compounds, Heterocyclic / therapeutic use
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Down-Regulation / drug effects
  • Ephrin-A2 / metabolism
  • Female
  • Focal Adhesion Protein-Tyrosine Kinases / metabolism
  • Gallbladder Neoplasms / blood supply*
  • Gallbladder Neoplasms / drug therapy
  • Gallbladder Neoplasms / pathology*
  • Humans
  • Male
  • Mice
  • Microcirculation / drug effects*
  • Paxillin / metabolism
  • Signal Transduction / drug effects*
  • Survival Analysis
  • Xenograft Model Antitumor Assays

Substances

  • Antineoplastic Agents
  • Bridged Bicyclo Compounds, Heterocyclic
  • Ephrin-A2
  • Paxillin
  • norcantharidin
  • Focal Adhesion Protein-Tyrosine Kinases

Grants and funding

This study was supported by grants from the National Nature Science Foundation of China (30672073, 81372614). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.