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A novel antiapoptotic mechanism based on interference of Fas signaling by CD44 variant isoforms

A Mielgo1, M van Driel, A Bloem

  • 11Institute of Medical Microbiology, Department of Clinical and Biological Sciences, University of Basel, CH 4003 Basel, Switzerland.

Cell Death and Differentiation
|September 17, 2005
PubMed

Insights

Tumor and inflammatory cells resist programmed cell death via CD44 variant isoforms (CD44v). CD44v6 and CD44v9 block Fas-mediated apoptosis, offering new therapeutic targets for cancer and autoimmunity.

Area of Science:

  • Molecular Biology
  • Immunology
  • Cell Biology

Background:

  • Tumor and inflammatory cells often exhibit resistance to programmed cell death (apoptosis).
  • This resistance makes them refractory to apoptosis-inducing signals like Fas (FAS, APO-1).
  • The transmembrane receptor CD44 and its variant isoforms (CD44v) are found on these resistant cells.

Purpose of the Study:

  • To investigate the role of CD44 variant isoforms in resistance to Fas-mediated apoptosis.
  • To determine if specific CD44v isoforms can block programmed cell death.
  • To explore the potential of targeting CD44v for therapeutic strategies.

Main Methods:

  • Generation of transfectants expressing different CD44v isoforms.
  • Assessment of the antiapoptotic effects of CD44v isoforms.
  • Analysis of CD44v and Fas colocalization and interaction.
  • Inhibition of CD44v6 function using a specific antibody.

Main Results:

  • CD44v6 and CD44v9 isoforms demonstrated an antiapoptotic effect, blocking Fas-mediated apoptosis.
  • CD44v6 and CD44v9 were found to colocalize and interact with the Fas receptor.
  • An anti-CD44v6 antibody successfully abolished the antiapoptotic function of CD44v6.
  • These findings indicate that CD44v isoforms interfere with Fas signaling pathways.

Conclusions:

  • CD44v isoforms, particularly CD44v6 and CD44v9, play a significant role in preventing Fas-mediated apoptosis.
  • The interaction between CD44v isoforms and Fas represents a novel mechanism in cell death resistance.
  • Targeting CD44v isoforms presents a promising new strategy for treating cancer and autoimmune diseases.

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