Phosphorylation of RelA/p65 promotes DNMT-1 recruitment to chromatin and represses transcription of the tumor metastasis suppressor gene BRMS1

Oncogene. 2012 Mar 1;31(9):1143-54. doi: 10.1038/onc.2011.308. Epub 2011 Jul 18.

Abstract

The majority of patients with lung cancer present with metastatic disease. Chronic inflammation and subsequent activation of nuclear factor-κB (NF-κB) have been associated with the development of cancers. The RelA/p65 subunit of NF-κB is typically associated with transcriptional activation. In this report we show that RelA/p65 can function as an active transcriptional repressor through enhanced methylation of the BRMS1 (breast cancer metastasis suppressor 1) metastasis suppressor gene promoter via direct recruitment of DNMT-1 (DNA (cytosine-5)-methyltransferase 1) to chromatin in response to tumor necrosis factor (TNF). TNF-mediated phosphorylation of S276 on RelA/p65 is required for RelA/p65-DNMT-1 interactions, chromatin loading of DNMT-1 and subsequent BRMS1 promoter methylation and transcriptional repression. The ability of RelA/p65 to function as an active transcriptional repressor is promoter specific, as the NF-κB-regulated gene cIAP2 (cellular inhibitor of apoptosis 2) is transcriptionally activated whereas BRMS1 is repressed under identical conditions. Small-molecule inhibition of either of the minimal interacting domains between RelA/p65-DNMT-1 and RelA/p65-BRMS1 promoter abrogates BRMS1 methylation and its transcriptional repression. The ability of RelA/p65 to directly recruit DNMT-1 to chromatin, resulting in promoter-specific methylation and transcriptional repression of tumor metastasis suppressor gene BRMS1, highlights a new mechanism through which NF-κB can regulate metastatic disease, and offers a potential target for newer-generation epigenetic oncopharmaceuticals.

Publication types

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

MeSH terms

  • Binding Sites / genetics
  • Cell Line, Tumor
  • Chromatin / metabolism*
  • CpG Islands
  • DNA (Cytosine-5-)-Methyltransferase 1
  • DNA (Cytosine-5-)-Methyltransferases / metabolism*
  • DNA Methylation
  • Gene Expression Regulation, Neoplastic
  • HEK293 Cells
  • Humans
  • Models, Biological
  • Neoplasm Proteins / genetics*
  • Phosphorylation / drug effects
  • Promoter Regions, Genetic
  • Protein Binding
  • Repressor Proteins
  • Serine / metabolism
  • Transcription Factor RelA / chemistry
  • Transcription Factor RelA / metabolism*
  • Transcription, Genetic* / drug effects
  • Tumor Necrosis Factors / pharmacology

Substances

  • BRMS1 protein, human
  • Chromatin
  • Neoplasm Proteins
  • Repressor Proteins
  • Transcription Factor RelA
  • Tumor Necrosis Factors
  • Serine
  • DNA (Cytosine-5-)-Methyltransferase 1
  • DNA (Cytosine-5-)-Methyltransferases
  • DNMT1 protein, human