Transcriptional repression of NFKBIA triggers constitutive IKK- and proteasome-independent p65/RelA activation in senescence

EMBO J. 2021 Mar 15;40(6):e104296. doi: 10.15252/embj.2019104296. Epub 2021 Jan 18.


The IκB kinase (IKK)-NF-κB pathway is activated as part of the DNA damage response and controls both inflammation and resistance to apoptosis. How these distinct functions are achieved remained unknown. We demonstrate here that DNA double-strand breaks elicit two subsequent phases of NF-κB activation in vivo and in vitro, which are mechanistically and functionally distinct. RNA-sequencing reveals that the first-phase controls anti-apoptotic gene expression, while the second drives expression of senescence-associated secretory phenotype (SASP) genes. The rapidly activated first phase is driven by the ATM-PARP1-TRAF6-IKK cascade, which triggers proteasomal destruction of inhibitory IκBα, and is terminated through IκBα re-expression from the NFKBIA gene. The second phase, which is activated days later in senescent cells, is on the other hand independent of IKK and the proteasome. An altered phosphorylation status of NF-κB family member p65/RelA, in part mediated by GSK3β, results in transcriptional silencing of NFKBIA and IKK-independent, constitutive activation of NF-κB in senescence. Collectively, our study reveals a novel physiological mechanism of NF-κB activation with important implications for genotoxic cancer treatment.

Keywords: DNA damage response; IκBα; NF-κB; SASP; senescence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Cell Line
  • Cell Proliferation / genetics
  • Cellular Senescence / physiology*
  • DNA Breaks, Double-Stranded
  • DNA Repair / genetics
  • Female
  • Gene Silencing / physiology
  • Glycogen Synthase Kinase 3 beta / metabolism
  • HEK293 Cells
  • Humans
  • I-kappa B Kinase / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • NF-KappaB Inhibitor alpha / biosynthesis*
  • NF-KappaB Inhibitor alpha / genetics
  • Phosphorylation
  • Proteasome Endopeptidase Complex / metabolism
  • Transcription Factor RelA / metabolism*
  • Transcription, Genetic / genetics*


  • NFKBIA protein, human
  • RELA protein, human
  • Transcription Factor RelA
  • NF-KappaB Inhibitor alpha
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • I-kappa B Kinase
  • Proteasome Endopeptidase Complex

Associated data

  • GEO/GSE158743