The ING4 tumor suppressor attenuates NF-kappaB activity at the promoters of target genes

Mol Cell Biol. 2008 Nov;28(21):6632-45. doi: 10.1128/MCB.00697-08. Epub 2008 Sep 8.

Abstract

The NF-kappaB family mediates immune and inflammatory responses. In many cancers, NF-kappaB is constitutively activated and induces the expression of genes that facilitate tumorigenesis. ING4 is a tumor suppressor that is absent or mutated in several cancers. Herein, we demonstrate that in human gliomas, NF-kappaB is constitutively activated, ING4 expression is negligible, and NF-kappaB-regulated gene expression is elevated. We demonstrate that an ING4 and NF-kappaB interaction exists but does not prevent NF-kappaB activation, nuclear translocation, or DNA binding. Instead, ING4 and NF-kappaB bind simultaneously at NF-kappaB-regulated promoters, and this binding correlates with reductions in p65 phosphorylation, p300, and the levels of acetylated histones and H3-Me3K4, while enhancing the levels of HDAC-1 at these promoters. Using a knockdown approach, we correlate reductions in ING4 protein levels with increased basal and inducible NF-kappaB target gene expression. Collectively, these data suggest that ING4 may specifically regulate the activity of NF-kappaB molecules that are bound to target gene promoters.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Proteins / metabolism*
  • Cell Line, Tumor
  • Cell Nucleus / drug effects
  • Cell Nucleus / metabolism
  • Cyclooxygenase 2 / genetics
  • Cyclooxygenase 2 / metabolism
  • Dose-Response Relationship, Drug
  • E1A-Associated p300 Protein / metabolism
  • Gene Expression Regulation, Neoplastic / drug effects
  • Genes, Neoplasm*
  • Glioma / enzymology
  • Glioma / genetics*
  • Histone Deacetylase 1
  • Histone Deacetylases / metabolism
  • Histones / metabolism
  • Homeodomain Proteins / metabolism*
  • Humans
  • Matrix Metalloproteinase 9 / genetics
  • Matrix Metalloproteinase 9 / metabolism
  • NF-kappa B / metabolism*
  • Promoter Regions, Genetic / genetics*
  • Protein Binding / drug effects
  • Protein Transport / drug effects
  • RNA, Small Interfering / pharmacology
  • Transcription Factor RelA / metabolism
  • Transcription, Genetic / drug effects
  • Tumor Suppressor Proteins / metabolism*

Substances

  • Cell Cycle Proteins
  • Histones
  • Homeodomain Proteins
  • ING4 protein, human
  • NF-kappa B
  • RNA, Small Interfering
  • Transcription Factor RelA
  • Tumor Suppressor Proteins
  • Cyclooxygenase 2
  • PTGS2 protein, human
  • E1A-Associated p300 Protein
  • EP300 protein, human
  • Matrix Metalloproteinase 9
  • HDAC1 protein, human
  • Histone Deacetylase 1
  • Histone Deacetylases