Anti-tumor activity of oridonin on SNU-5 subcutaneous xenograft model via regulation of c-Met pathway

Tumour Biol. 2014 Sep;35(9):9139-46. doi: 10.1007/s13277-014-2178-4. Epub 2014 Jun 12.

Abstract

Gastric cancer is the leading cause of cancer death worldwide. Oridonin, a diterpenoid isolated from Rabdosia rubescens, has attracted considerable attention as a potential treatment for gastric cancer based on its anti-tumor effects in many tumor cell lines. However, detailed anti-tumor mechanisms of oridonin remain a matter of speculation. In the present study, a gastric carcinoma cell line harboring c-Met gene amplification SNU-5 was used to investigate the underlying mechanisms. The results showed that in vitro, oridonin potently inhibited c-Met phosphorylation and c-Met-dependent cell proliferation (IC50 value, 36.8 μM), meanwhile down-regulated the expression of the downstream signaling molecules including phospho-c-Raf, phospho-Erk, and phospho-Akt. In vivo, oridonin showed efficacy at well-tolerated doses, including marked cytoreductive anti-tumor activity in SNU-5 subcutaneous xenograft model. The anti-tumor efficacy of oridonin was dose-dependent and showed strong inhibition of c-Met phosphorylation. Additional mechanism of action studies showed dose-dependent inhibition of c-Met-dependent signal transduction, tumor cell proliferation (Ki67), and reduction of microvessel density (CD31). These results suggested that the anti-tumor activity of oridonin may be mediated by direct effects on tumor cell growth or survival as well as anti-angiogenic mechanisms. In summary, the results indicated that oridonin exerted anti-tumor growth on human gastric cancer SNU-5 in vitro and in vivo by direct regulation of c-Met signaling pathway and the anti-tumor effects was mainly based on its anti-proliferation and anti-angiogenesis.

MeSH terms

  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Diterpenes, Kaurane / chemistry
  • Diterpenes, Kaurane / pharmacology*
  • Dose-Response Relationship, Drug
  • Female
  • Humans
  • Immunoblotting
  • Immunohistochemistry
  • Inhibitory Concentration 50
  • Ki-67 Antigen / metabolism
  • Mice, Inbred BALB C
  • Mice, Nude
  • Molecular Structure
  • Neovascularization, Pathologic / metabolism
  • Neovascularization, Pathologic / pathology
  • Neovascularization, Pathologic / prevention & control
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphorylation / drug effects
  • Platelet Endothelial Cell Adhesion Molecule-1 / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Proto-Oncogene Proteins c-met / metabolism*
  • Signal Transduction / drug effects*
  • Stomach Neoplasms / drug therapy*
  • Stomach Neoplasms / metabolism
  • Stomach Neoplasms / pathology
  • Xenograft Model Antitumor Assays*

Substances

  • Antineoplastic Agents
  • Diterpenes, Kaurane
  • Ki-67 Antigen
  • Platelet Endothelial Cell Adhesion Molecule-1
  • oridonin
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-met
  • Proto-Oncogene Proteins c-akt