Activation of caspase-3 alone is insufficient for apoptotic morphological changes in human neuroblastoma cells

J Neurochem. 2002 Mar;80(6):1039-48. doi: 10.1046/j.0022-3042.2002.00787.x.

Abstract

Activated caspase-3 is considered an important enzyme in the cell death pathway. To study the specific role of caspase-3 activation in neuronal cells, we generated a stable tetracycline-regulated SK-N-MC neuroblastoma cell line, which expressed a highly efficient self-activating chimeric caspase-3, consisting of the caspase-1 prodomain fused to the caspase-3 catalytic domain. Under expression-inducing conditions, we observed a time-dependent increase of processed caspase-3 by immunostaining for the active form of the enzyme, intracellular caspase-3 enzyme activity, as well as poly(ADP-ribose) polymerase (PARP) cleavage. Induced expression of the caspase fusion protein showed predominantly caspase-3 activity without any apoptotic morphological changes. In contrast, staurosporine treatment of the same cells resulted in activation of multiple caspases and profound apoptotic morphology. Our work provides evidence that auto-activation of caspase-3 can be efficiently achieved with a longer prodomain and that neuronal cell apoptosis may require another caspase or activation of multiple caspase enzymes.

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Apoptosis / drug effects
  • Apoptosis / physiology*
  • Blotting, Western
  • Caspase 3
  • Caspases / genetics
  • Caspases / metabolism*
  • Cell Survival / drug effects
  • Doxycycline / pharmacology
  • Enzyme Activation / drug effects
  • Enzyme Activation / physiology
  • Enzyme Inhibitors / pharmacology
  • Gene Expression
  • Humans
  • Neuroblastoma / metabolism*
  • Neuroblastoma / pathology
  • Protein Structure, Tertiary / physiology
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Staurosporine / pharmacology
  • Transfection
  • Tumor Cells, Cultured

Substances

  • Anti-Bacterial Agents
  • Enzyme Inhibitors
  • Recombinant Fusion Proteins
  • CASP3 protein, human
  • Caspase 3
  • Caspases
  • Staurosporine
  • Doxycycline