Endoplasmic Reticulum Stress Stimulates p53 Expression Through NF-κB Activation

PLoS One. 2012;7(7):e39120. doi: 10.1371/journal.pone.0039120. Epub 2012 Jul 30.

Abstract

Background: Induction of apoptosis by endoplasmic reticulum (ER) stress is implicated as the major factor in the development of multiple diseases. ER stress also appears to be a potentially useful major response to many chemotherapeutic drugs and environmental chemical compounds. A previous study has indicated that one major apoptotic regulator, p53, is significantly increased in response to ER stress, and participates in ER stress-induced apoptosis. However, the regulators of p53 expression during ER stress are still not fully understood.

Principal findings: In this report, we demonstrate that induction of p53 expression is mediated through NF-κB signaling pathways during ER stress in MCF-7 cells. Tunicamycin or brefeldin A, two ER stress inducers, increased p53 expression in MCF-7 and Hela cells. We found p53 nuclear localization, activity, and phosphorylation at serine 15 on p53 increased during ER stress. Nuclear translocation of NF-κB and activity of NF-κB were also observed during ER stress. ER stress-induced p53 expression was significantly inhibited by coincubation with the NF-κB inhibitor, Bay 11-7082 and downregulation of NF-κB p65 expression. The role of p53 in mediating Brefeldin A-induced apoptosis was also investigated. Induction of p53 expression by Brefeldin A was correlated to Brefeldin A-induced apoptosis. Furthermore, downregulation of p53 expression by p53 siRNA significantly reduced Brefeldin A-induced apoptosis in MCF-7 cells.

Significance: Taken together, NF-κB activation and induction of p53 expression is essential for ER stress-induced cell death which is important for therapeutic effects of clinical cancer drugs. Our results may provide insight into the mechanism of cancer chemotherapy efficacy that is associated with induction of ER stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis
  • Brefeldin A / pharmacology
  • Cycloheximide / pharmacology
  • Dactinomycin / pharmacology
  • Endoplasmic Reticulum Stress*
  • Glycogen Synthase Kinase 3 / metabolism
  • Glycogen Synthase Kinase 3 beta
  • HCT116 Cells
  • HeLa Cells
  • Humans
  • MCF-7 Cells
  • NF-kappa B / metabolism*
  • Phosphorylation
  • Protein Processing, Post-Translational
  • Protein Synthesis Inhibitors / pharmacology
  • Signal Transduction
  • Transcription, Genetic / drug effects
  • Transcriptional Activation*
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*

Substances

  • NF-kappa B
  • Protein Synthesis Inhibitors
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • Dactinomycin
  • Brefeldin A
  • Cycloheximide
  • Glycogen Synthase Kinase 3 beta
  • Glycogen Synthase Kinase 3

Grant support

This work has been supported by a research grant from the National Science Council on Taiwan (NSC 99-2320-B-041-001), and in part by grant CN9911 to Dr. Jui-Hsiang Hung from Chia-Nan University of Pharmacy & Science, Tainan, Taiwan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.