Piperlongumine induces cell death through ROS-mediated CHOP activation and potentiates TRAIL-induced cell death in breast cancer cells

J Cancer Res Clin Oncol. 2014 Dec;140(12):2039-46. doi: 10.1007/s00432-014-1777-1. Epub 2014 Jul 15.

Abstract

Purpose: Piperlongumine (PL) has been shown to selectively induce apoptotic cell death in cancer cells via reactive oxygen species (ROS) accumulation. In this study, we characterized a molecular mechanism for PL-induced cell death.

Methods: Cell viability and cell death were assessed by MTT assay and Annexin V-FITC/PI staining, respectively. ROS generation was measured using the H2DCFDA. Small interfering RNA (siRNA) was used for suppressing gene expression. The mRNA and protein expression were analyzed by RT-PCR and Western blot analysis, respectively.

Results: We found that PL promotes C/EBP homologous protein (CHOP) induction, which leads to the up-regulation of its targets Bim and DR5. Pretreatment with the ROS scavenger N-acetyl-cysteine abolishes the PL-induced up-regulation of CHOP and its target genes, suggesting an essential role for ROS in PL-induced CHOP activation. The down-regulation of CHOP or Bim with siRNA efficiently attenuates PL-induced cell death, suggesting a critical role for CHOP in this cell death. Furthermore, PL potentiates TRAIL-induced cytotoxicity in breast cancer cells by upregulating DR5, as DR5 knockdown abolished the sensitizing effect of PL on TRAIL responses.

Conclusions: Overall, our data suggest a new mechanism for the PL-induced cell death in which ROS mediates CHOP activation, and combination treatment with PL and TRAIL could be a potential strategy for breast cancer therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects*
  • Apoptosis Regulatory Proteins / physiology
  • Bcl-2-Like Protein 11
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Dioxolanes / pharmacology*
  • Female
  • Humans
  • Membrane Proteins / physiology
  • Proto-Oncogene Proteins / physiology
  • Reactive Oxygen Species / metabolism*
  • Receptors, TNF-Related Apoptosis-Inducing Ligand / physiology
  • TNF-Related Apoptosis-Inducing Ligand / pharmacology*
  • Transcription Factor CHOP / metabolism*

Substances

  • Apoptosis Regulatory Proteins
  • BCL2L11 protein, human
  • Bcl-2-Like Protein 11
  • DDIT3 protein, human
  • Dioxolanes
  • Membrane Proteins
  • Proto-Oncogene Proteins
  • Reactive Oxygen Species
  • Receptors, TNF-Related Apoptosis-Inducing Ligand
  • TNF-Related Apoptosis-Inducing Ligand
  • Transcription Factor CHOP
  • piperlonguminine