The mechanism of how CD95/Fas activates the Type I IFN/STAT1 axis, driving cancer stemness in breast cancer

Sci Rep. 2020 Jan 28;10(1):1310. doi: 10.1038/s41598-020-58211-3.

Abstract

CD95/Fas is an apoptosis inducing death receptor. However, it also has multiple nonapoptotic activities that are tumorigenic. Chronic stimulation of CD95 on breast cancer cells can increase their cancer initiating capacity through activation of a type I interferon (IFN-I)/STAT1 pathway when caspases are inhibited. We now show that this activity relies on the canonical components of the CD95 death-inducing signaling complex, FADD and caspase-8, and on the activation of NF-κB. We identified caspase-2 as the antagonistic caspase that downregulates IFN-I production. Once produced, IFN-Is bind to their receptors activating both STAT1 and STAT2 resulting in upregulation of the double stranded (ds)RNA sensor proteins RIG-I and MDA5, and a release of a subset of endogenous retroviruses. Thus, CD95 is part of a complex cell autonomous regulatory network that involves activation of innate immune components that drive cancer stemness and contribute to therapy resistance.

MeSH terms

  • Breast Neoplasms / etiology
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Caspase 8 / metabolism
  • Cell Death
  • Fas-Associated Death Domain Protein / metabolism
  • Female
  • Humans
  • Immunity
  • Interferon Regulatory Factor-3 / metabolism
  • Interferon Regulatory Factor-7 / metabolism
  • Interferon Type I / metabolism*
  • Mitochondria / metabolism
  • NF-kappa B / metabolism
  • Neoplastic Stem Cells / metabolism*
  • Neoplastic Stem Cells / pathology
  • RNA, Double-Stranded / genetics
  • RNA, Double-Stranded / immunology
  • STAT1 Transcription Factor / metabolism*
  • Signal Transduction*
  • fas Receptor / metabolism*

Substances

  • FADD protein, human
  • FAS protein, human
  • Fas-Associated Death Domain Protein
  • IRF3 protein, human
  • IRF7 protein, human
  • Interferon Regulatory Factor-3
  • Interferon Regulatory Factor-7
  • Interferon Type I
  • NF-kappa B
  • RNA, Double-Stranded
  • STAT1 Transcription Factor
  • STAT1 protein, human
  • fas Receptor
  • Caspase 8