Caspase-dependent generation of reactive oxygen species in human astrocytoma cells contributes to resistance to TRAIL-mediated apoptosis

Cell Death Differ. 2010 May;17(5):833-45. doi: 10.1038/cdd.2009.154. Epub 2009 Oct 30.


Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF family of cytokines, causes apoptosis by caspase activation in various cell types, particularly in transformed cells. Numerous types of tumors are relatively resistant to TRAIL-induced cytotoxicity; however, the reasons for this are not yet fully understood. We report here a new signal transduction pathway involving protein kinase Cdelta (PKCdelta), NADPH oxidase 4 (NOX4) and reactive oxygen species (ROS), that inhibits caspase-dependent cell death induced by TRAIL ligation in human malignant astrocytoma cells. In our experiments, TRAIL ligation-induced generation of intracellular ROS through caspase-dependent proteolytic activation of PKCdelta and subsequent activation of the NOX4 complex. Suppression of intracellular ROS induction using various pharmacological inhibitors or PKCdelta- or NOX4-specific RNA interference enhanced the enzymatic activity of caspase-3 by blocking the oxidative modification of its catalytic cysteine residue, resulting in marked augmentation of TRAIL-mediated cell death. These results collectively indicate that TRAIL-induced activation of PKCdelta and NOX4 can modulate TRAIL-mediated apoptosis by promoting oxidative modification of active caspase-3 in a negative-feedback manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / physiology*
  • Astrocytoma / metabolism*
  • Caspase 3 / metabolism*
  • Cell Line, Tumor
  • Electrophoresis, Gel, Two-Dimensional
  • Humans
  • Immunoblotting
  • NADPH Oxidase 4
  • NADPH Oxidases / metabolism
  • Reactive Oxygen Species / metabolism*
  • TNF-Related Apoptosis-Inducing Ligand / metabolism*


  • Reactive Oxygen Species
  • TNF-Related Apoptosis-Inducing Ligand
  • NADPH Oxidase 4
  • NADPH Oxidases
  • NOX4 protein, human
  • Caspase 3