Alpha-tocopheryl succinate inhibits malignant mesothelioma by disrupting the fibroblast growth factor autocrine loop: mechanism and the role of oxidative stress

J Biol Chem. 2005 Jul 8;280(27):25369-76. doi: 10.1074/jbc.M414498200. Epub 2005 May 5.

Abstract

We have studied the potential effect against human malignant mesotheliomas (MM) of alpha-tocopheryl succinate (alpha-TOS), a redox-silent vitamin E analog with strong pro-apoptotic and anti-cancer activity. alpha-TOS at sub-apoptotic levels inhibited proliferation of MM cell lines, while being nontoxic to nonmalignant mesothelial cells. Because MM cells are typified by a highly metastatic phenotype, we investigated the effect of alpha-TOS on genes playing a major role in MM progression. Of these, alpha-TOS down regulated fibroblast growth factor (FGF)-1 and, in particular, FGF-2 on the transcriptional level in MM cells, and this was not observed in their nonmalignant counterparts. FGF-2 short interfering RNA suppressed proliferation of MM cells. Down-regulation of FGF-2 was likely because of inhibition of the egr-1 transcription activity that was decreased in MM cells via oxidative stress induced by alpha-TOS, as evidenced by EPR spectroscopy, whereas nonmalignant cells did not show this response. Treatment of MM cells with egr-1 short interfering RNA suppressed proliferation, which was overridden by exogenously added recombinant FGF-1 and, in particular, FGF-2. An analog of coenzyme Q targeted to mitochondria and superoxide dismutase overrode inhibition of MM cell proliferation by alpha-TOS as well as alpha-TOS-induced inhibition of egr-1-dependent transactivation. Finally, alpha-TOS significantly suppressed experimental MM in immunocompromised mice. Our data suggest that alpha-TOS suppresses MM cell proliferation by disrupting the FGF-FGF receptor autocrine signaling loop by generating oxidative stress and point to the agent as a selective drug against thus far fatal mesotheliomas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Autocrine Communication / drug effects*
  • Cell Division / drug effects
  • Cell Line, Tumor
  • DNA, Single-Stranded / metabolism
  • Down-Regulation / drug effects
  • Fibroblast Growth Factor 1 / antagonists & inhibitors
  • Fibroblast Growth Factor 1 / genetics
  • Fibroblast Growth Factor 1 / metabolism
  • Fibroblast Growth Factor 2 / antagonists & inhibitors*
  • Fibroblast Growth Factor 2 / genetics
  • Fibroblast Growth Factor 2 / metabolism
  • Gene Expression / drug effects
  • Humans
  • Mesothelioma / drug therapy*
  • Mesothelioma / physiopathology
  • Oxidative Stress*
  • Reactive Oxygen Species / metabolism
  • Signal Transduction / drug effects
  • Tocopherols
  • Vitamin E / analogs & derivatives*
  • Vitamin E / pharmacology*

Substances

  • Antineoplastic Agents
  • DNA enzyme ED5
  • DNA, Single-Stranded
  • Reactive Oxygen Species
  • Fibroblast Growth Factor 2
  • Fibroblast Growth Factor 1
  • Vitamin E
  • Tocopherols