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Antianoikis effect of nuclear factor-kappaB through up-regulated expression of osteoprotegerin, BCL-2, and IAP-1

Murat Toruner1, Martin Fernandez-Zapico, Jing Jing Sha

  • 1Gastroenterology Research Unit and Molecular Medicine Program, Mayo Clinic, Rochester, Minnesota 55905, USA.

The Journal of Biological Chemistry
|January 13, 2006
PubMed

Insights

Epithelial cells avoid anoikis (programmed cell death) through NF-kappaB activation, which upregulates anti-apoptotic genes like osteoprotegerin and BCL-2. This identifies a novel pathway protecting intestinal cells from anoikis.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Cancer Biology

Background:

  • Anoikis is programmed cell death in epithelial cells detached from their matrix.
  • The molecular mechanisms regulating anoikis in intestinal epithelial cells are not fully understood.

Purpose of the Study:

  • To investigate the role of transcription factor NF-kappaB in anoikis susceptibility of intestinal epithelial cells.
  • To elucidate the signaling pathway and downstream targets involved in NF-kappaB-mediated anoikis resistance.

Main Methods:

  • Rat intestinal epithelial cells cultured in suspension to induce anoikis.
  • Assessed NF-kappaB activation via DNA fragmentation and caspase-3 cleavage.
  • Investigated signaling cascade using focal adhesion kinase, PI3K, and AKT.
  • Analyzed gene expression (osteoprotegerin, BCL-2, IAP-1) via chromatin immunoprecipitation and RNA interference.

Main Results:

  • Suspension culture activated NF-kappaB, inhibiting anoikis.
  • NF-kappaB activation required focal adhesion kinase phosphorylation and involved PI3K/AKT signaling.
  • NF-kappaB directly upregulated osteoprotegerin, BCL-2, and IAP-1, which are key inhibitors of anoikis.
  • Knock-down of these genes increased anoikis; their reconstitution restored anoikis resistance.

Conclusions:

  • Identified a novel NF-kappaB-dependent antianoikis pathway in intestinal epithelial cells.
  • This pathway involves the coordinated upregulation of osteoprotegerin, BCL-2, and IAP-1.
  • Findings provide molecular insights into anoikis regulation and potential therapeutic targets.

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