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The Btk-dependent PIP5K1γ lipid kinase activation by Fas counteracts FasL-induced cell death

Aurélie Rossin1, Nadia Lounnas1, Jérôme Durivault1

  • 1Université Côte d'Azur, Institut de Biologie Valrose, CNRS UMR 7277, Inserm UMR 1091, Parc Valrose, Bâtiment des Sciences Naturelles, 06108, Nice Cedex2, France.

Apoptosis : an International Journal on Programmed Cell Death
|September 8, 2017
PubMed

Insights

Bruton's tyrosine kinase (Btk) negatively regulates FasL-induced apoptosis in colon cancer cells. Btk and PIP5K1γ cooperate to produce PI(4,5)P2, controlling cell death.

Area of Science:

  • Cell Biology
  • Molecular Oncology
  • Immunology

Background:

  • The Fas/FasL system is crucial for apoptosis and cancer immune evasion.
  • Fas receptor-mediated apoptosis is tightly regulated to prevent unwanted cell death.
  • Btk's role in FasL-mediated apoptosis is primarily studied in B cells and poorly understood in other cell types.

Purpose of the Study:

  • To investigate the role of Bruton's tyrosine kinase (Btk) in regulating FasL-mediated apoptosis in colorectal cancer cells.
  • To elucidate the molecular mechanisms by which Btk controls FasL-induced cell death.
  • To identify potential interactions and signaling pathways involved in this regulation.

Main Methods:

  • Utilized colon cancer epithelial cell lines.
  • Investigated the effect of Btk activity on FasL-mediated cell death.
  • Examined the interaction between Btk, Fas, and PIP5K1γ.
  • Assessed the role of PI(4,5)P2 production in apoptosis regulation.
  • Employed gene knockdown of PIP5K1γ to evaluate its impact on apoptotic signaling.

Main Results:

  • Btk negatively regulates FasL-mediated cell death in colon cancer epithelial cells via its tyrosine kinase activity.
  • Btk interacts with both Fas and PIP5K1γ.
  • FasL stimulation induces rapid PI(4,5)P2 synthesis, dependent on Btk's presence and kinase activity.
  • Knockdown of PIP5K1γ enhances FasL-induced apoptosis, confirming its role in negative regulation.
  • Btk and PIP5K1γ cooperate in FasL-induced PI(4,5)P2 production.

Conclusions:

  • Btk and PIP5K1γ play a cooperative role in regulating FasL-induced PI(4,5)P2 production in colorectal cancer cells.
  • This Btk-PIP5K1γ-PI(4,5)P2 pathway acts as a critical threshold regulator for FasL-induced apoptotic commitment.
  • Understanding this mechanism could offer new therapeutic strategies targeting colorectal cancer cell death pathways.
Keywords:
BtkCell deathFasPI(4,5)P2PIP5K1γ

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