Y-tocotrienol inhibits angiogenesis-dependent growth of human hepatocellular carcinoma through abrogation of AKT/mTOR pathway in an orthotopic mouse model

Oncotarget. 2014 Apr 15;5(7):1897-911. doi: 10.18632/oncotarget.1876.

Abstract

Angiogenesis is one of the key hallmarks of cancer. In this study, we investigated whether γ-tocotrienol can abrogate angiogenesis-mediated tumor growth in hepatocellular carcinoma (HCC) and if so, through what molecular mechanisms. We observed that γ-tocotrienol inhibited vascular endothelial growth factor (VEGF)-induced migration, invasion, tube formation and viability of HUVECs in vitro. Moreover, γ-tocotrienol reduced the number of capillary sprouts from matrigel embedded rat thoracic aortic ring in a dose-dependent manner. Also, in chick chorioallantoic membrane assay, γ-tocotrienol significantly reduced the blood vessels formation. We further noticed that γ-tocotrienol blocked angiogenesis in an in vivo matrigel plug assay. Furthermore, γ-tocotrienol inhibited VEGF-induced autophosphorylation of VEGFR2 in HUVECs and also suppressed the constitutive activation of AKT/mammalian target of rapamycin (mTOR) signal transduction cascades in HUVECs as well as in HCC cells. Interestingly, γ-tocotrienol was also found to significantly reduce the tumor growth in an orthotopic HCC mouse model and inhibit tumor-induced angiogenesis in HCC patient xenografts through the suppression of various biomarkers of proliferation and angiogenesis. Taken together, our findings strongly suggest that γ-tocotrienol might be a promising anti-angiogenic drug with significant antitumor activity in HCC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Carcinoma, Hepatocellular / blood supply
  • Carcinoma, Hepatocellular / chemistry
  • Carcinoma, Hepatocellular / drug therapy*
  • Caspase 3 / analysis
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • Chick Embryo
  • Chromans / pharmacology*
  • Endothelial Cells
  • Humans
  • Ki-67 Antigen / analysis
  • Liver Neoplasms / blood supply
  • Liver Neoplasms / chemistry
  • Liver Neoplasms / drug therapy*
  • Mice
  • Mice, SCID
  • Models, Animal
  • Neovascularization, Pathologic / metabolism
  • Neovascularization, Pathologic / prevention & control*
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Signal Transduction / drug effects
  • Vascular Endothelial Growth Factor A / pharmacology
  • Vitamin E / analogs & derivatives*
  • Vitamin E / pharmacology

Substances

  • Antineoplastic Agents
  • Chromans
  • Ki-67 Antigen
  • Vascular Endothelial Growth Factor A
  • Vitamin E
  • plastochromanol 8
  • Proto-Oncogene Proteins c-akt
  • Caspase 3