Akt protein kinase inhibits non-apoptotic programmed cell death induced by ceramide

J Biol Chem. 2002 Jan 25;277(4):2790-7. doi: 10.1074/jbc.M106361200. Epub 2001 Nov 12.

Abstract

A growing body of evidence now suggests that programmed cell death (PCD) occurs via non-apoptotic mechanisms as well as by apoptosis. In contrast to apoptosis, however, the molecular mechanisms involved in the regulation of non-apoptotic PCD remain only poorly understood. Here we show that ceramide induces a non-apoptotic PCD with a necrotic-like morphology in human glioma cells. Characteristically, the cell death was not accompanied by loss of the mitochondrial transmembrane potential, cytosolic release of cytochrome c from mitochondria, or the activation of the caspase cascade. Consistent with these characteristics, this ceramide-induced cell death was inhibited neither by the overexpression of Bcl-xL nor by the pan-caspase inhibitor zVAD-fmk. However, strikingly, the ceramide-induced non-apoptotic cell death was inhibited by the activation of the Akt/protein kinase B pathway through the expression of a constitutively active version of Akt. The results for the first time indicate that the Akt kinase, known to play an essential role in survival factor-mediated inhibition of apoptotic cell death, is also involved in the regulation of non-apoptotic PCD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae / genetics
  • Amino Acid Chloromethyl Ketones / pharmacology
  • Apoptosis*
  • Caspases / metabolism
  • Cell Death*
  • Cell Membrane / enzymology
  • Cell Survival
  • Ceramides / metabolism
  • Ceramides / pharmacology*
  • Cysteine Proteinase Inhibitors / pharmacology
  • Cytochrome c Group / metabolism
  • Cytosol / enzymology
  • Enzyme Inhibitors / pharmacology
  • Glioma / metabolism
  • Humans
  • Immunoblotting
  • Membrane Potentials
  • Microscopy, Electron
  • Mitochondria / enzymology
  • Mitochondria / metabolism
  • Protein Binding
  • Protein Serine-Threonine Kinases*
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins / physiology*
  • Proto-Oncogene Proteins c-akt
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Signal Transduction
  • Tumor Cells, Cultured
  • bcl-X Protein

Substances

  • Amino Acid Chloromethyl Ketones
  • BCL2L1 protein, human
  • Ceramides
  • Cysteine Proteinase Inhibitors
  • Cytochrome c Group
  • Enzyme Inhibitors
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • bcl-X Protein
  • benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
  • AKT1 protein, human
  • Protein Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Caspases