Drug-mediated sensitization to TRAIL-induced apoptosis in caspase-8-complemented neuroblastoma cells proceeds via activation of intrinsic and extrinsic pathways and caspase-dependent cleavage of XIAP, Bcl-xL and RIP

Oncogene. 2004 Jul 15;23(32):5415-25. doi: 10.1038/sj.onc.1207704.


Neuroblastoma (NB) is a childhood neoplasm which heterogeneous behavior can be explained by differential regulation of apoptosis. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively induces rapid apoptosis in most tumor cells and thus represents a promising anticancer agent. We have reported silencing of caspase-8 expression in highly malignant NB cells as a possible mechanism of resistance to TRAIL-induced apoptosis. To explore the particular contribution of caspase-8 in such resistance, retroviral-mediated stable caspase-8 expression was induced in the IGR-N91 cells. As a result, sensitivity to TRAIL was fully restored in the caspase-8-complemented cells. TRAIL-induced cell death could be further enhanced by cotreatment of IGR-N91-C8 and SH-EP cells with cycloheximide or subtoxic concentrations of chemotherapeutic drugs in a caspase-dependent manner. Sensitization to TRAIL involved enhanced death receptor DR5 expression, activation of Bid and the complete caspases cascade. Interestingly, combined treatments also enhanced the cleavage-mediated inactivation of antiapoptotic molecules, XIAP, Bcl-x(L) and RIP. Our results show that restoration of active caspase-8 expression in a caspase-8-deficient NB cell line is necessary and sufficient to fully restore TRAIL sensitivity. Moreover, the synergistic effect of drugs and TRAIL results from activation of the caspase cascade via a mitochondrial pathway-mediated amplification loop and from the inactivation of apoptosis inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects*
  • Apoptosis Regulatory Proteins
  • Caspase 8
  • Caspases / metabolism*
  • Cycloheximide / pharmacology
  • Humans
  • Membrane Glycoproteins / pharmacology*
  • Mitochondria / drug effects
  • Neuroblastoma / drug therapy*
  • Neuroblastoma / metabolism
  • Neuroblastoma / pathology
  • Protein Synthesis Inhibitors / pharmacology
  • Proteins / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Receptor-Interacting Protein Serine-Threonine Kinases
  • Receptors, TNF-Related Apoptosis-Inducing Ligand
  • Receptors, Tumor Necrosis Factor / biosynthesis
  • Receptors, Tumor Necrosis Factor / drug effects
  • Receptors, Tumor Necrosis Factor / genetics
  • TNF-Related Apoptosis-Inducing Ligand
  • Tumor Cells, Cultured
  • Tumor Necrosis Factor-alpha / pharmacology*
  • X-Linked Inhibitor of Apoptosis Protein
  • bcl-X Protein


  • Antineoplastic Agents
  • Apoptosis Regulatory Proteins
  • BCL2L1 protein, human
  • Membrane Glycoproteins
  • Protein Synthesis Inhibitors
  • Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Receptors, TNF-Related Apoptosis-Inducing Ligand
  • Receptors, Tumor Necrosis Factor
  • TNF-Related Apoptosis-Inducing Ligand
  • TNFRSF10B protein, human
  • TNFSF10 protein, human
  • Tumor Necrosis Factor-alpha
  • X-Linked Inhibitor of Apoptosis Protein
  • XIAP protein, human
  • bcl-X Protein
  • Cycloheximide
  • RIPK1 protein, human
  • Receptor-Interacting Protein Serine-Threonine Kinases
  • CASP8 protein, human
  • Caspase 8
  • Caspases