Roles of the Akt/mTOR/p70S6K and ERK1/2 signaling pathways in curcumin-induced autophagy

Autophagy. Nov-Dec 2007;3(6):635-7. doi: 10.4161/auto.4916. Epub 2007 Aug 21.

Abstract

Curcumin has a potent anticancer effect and is a promising new therapeutic strategy. We previously demonstrated that curcumin induced non-apoptotic autophagic cell death in malignant glioma cells in vitro and in vivo. This compound inhibited the Akt/mammalian target of rapamycin/p70 ribosomal protein S6 kinase pathway and activated the extracellular signal-regulated kinases 1/2 thereby inducing autophagy. Interestingly, activation of the first pathway inhibited curcumin-induced autophagy and cytotoxicity, whereas inhibition of the latter pathway inhibited curcumin-induced autophagy and induced apoptosis, thus augmenting the cytotoxicity of curcumin. These results imply that these two autophagic pathways have opposite effects on curcumin's cytotoxicity. However, inhibition of nuclear factor kappaB, which is the main target of curcumin for its anticancer effect, was not observed in malignant glioma cells. These results suggest that autophagy but not nuclear factor kappaB plays a central role in curcumin anticancer therapy and warrant further investigation toward application in patients with malignant gliomas. Here, we discuss the therapeutic role of two autophagic pathways influenced by curcumin.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autophagy / drug effects
  • Autophagy / physiology*
  • Curcumin / pharmacology*
  • Enzyme Activation / drug effects
  • Extracellular Signal-Regulated MAP Kinases / physiology*
  • Humans
  • Models, Biological
  • Protein Kinases
  • Proto-Oncogene Proteins c-akt / physiology*
  • Ribosomal Protein S6 Kinases, 70-kDa / antagonists & inhibitors
  • Signal Transduction / drug effects*
  • TOR Serine-Threonine Kinases

Substances

  • Protein Kinases
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Ribosomal Protein S6 Kinases, 70-kDa
  • Extracellular Signal-Regulated MAP Kinases
  • Curcumin