Restoration of TRAIL-induced apoptosis in a caspase-8-deficient neuroblastoma cell line by stable re-expression of caspase-8

Ann N Y Acad Sci. 2003 Dec:1010:195-9. doi: 10.1196/annals.1299.033.

Abstract

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis in most tumor cells, a process sometimes potentiated by chemotherapeutic drugs or cycloheximide (CHX). Childhood neuroblastoma (NB) is a clinically and biologically heterogeneous neoplasm whose behavior can be explained by differential regulation of apoptosis. The non-invasive S-type NB cell lines are sensitive to TRAIL, whereas the invasive N-type NB cell lines are resistant. We have reported the silencing of caspase-8 expression in N-type cells as a possible mechanism of death receptor-mediated resistance to apoptosis in NB. The recently observed deregulation of caspase-10 in these cells prompted us to investigate the particular contribution of caspase-8 silencing in the resistance to TRAIL in N-type cells. Stable caspase-8 expression was therefore restored in the IGR-N91 cell line by retroviral infection. The IGR-N91-C8 cells became sensitive to TRAIL-mediated apoptosis, whereas the control vector-infected IGR-N91-M cells remained resistant. Interestingly, the apoptotic response to TRAIL was enhanced by co-treatment of SH-EP and IGR-N91-C8 cells with CHX or with sub-toxic concentration of doxorubicin (DOX) in a caspase-dependent manner, as cells could be protected from death by specific caspase-8 or pan-caspase inhibitors. CHX or DOX was shown to enhance TRAIL-induced caspase-8 activation and loss of mitochondrial transmembrane potential. In conclusion, restoration of active caspase-8 expression in caspase-8- and caspase-10-deficient IGR-N-91 cell line is necessary and sufficient to fully restore TRAIL-mediated cell death. Moreover, DOX and CHX were able to sensitize NB cell lines to TRAIL-induced apoptosis in a caspase-8-dependent manner by engaging death receptor and mitochondrial signaling pathways.

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Apoptosis / physiology*
  • Apoptosis Regulatory Proteins
  • Caspase 8
  • Caspases / deficiency
  • Caspases / genetics*
  • Caspases / metabolism*
  • Cell Death / physiology
  • Cell Line, Tumor
  • Cycloheximide / pharmacology
  • DNA Damage
  • Enzyme Activation / drug effects
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Membrane Glycoproteins / physiology*
  • Neuroblastoma
  • TNF-Related Apoptosis-Inducing Ligand
  • Tumor Necrosis Factor-alpha / physiology*

Substances

  • Apoptosis Regulatory Proteins
  • Membrane Glycoproteins
  • TNF-Related Apoptosis-Inducing Ligand
  • TNFSF10 protein, human
  • Tumor Necrosis Factor-alpha
  • Cycloheximide
  • CASP8 protein, human
  • Caspase 8
  • Caspases