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Caspase-3 mediated feedback activation of apical caspases in doxorubicin and TNF-alpha induced apoptosis

Shihe Yang1, Ann D Thor, Susan Edgerton

  • 1Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.

Apoptosis : an International Journal on Programmed Cell Death
|October 3, 2006
PubMed

Insights

Caspase-3, an effector caspase, also activates apical caspases (caspase-2, -8, -9, -10A) during apoptosis. This feedback loop enhances cancer cell death and may overcome drug resistance.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Cancer Research

Background:

  • Aberrant apoptosis is linked to cancer development and therapeutic resistance.
  • Caspase deficiency is common in various cancers.
  • Caspase-3 reconstitution sensitizes cancer cells to chemotherapy.

Purpose of the Study:

  • To investigate caspase-3's role in feedback activation of apical caspases (caspase-2, -8, -9, -10A).
  • To understand caspase-3's impact on doxorubicin and TNF-alpha induced apoptosis.
  • To explore the crosstalk between effector and apical caspases.

Main Methods:

  • Cell-free systems to assess caspase-3 mediated cleavage sensitivity.
  • Intact cell models (MCF-7/C3) to study apoptosis induction.
  • Analysis of caspase cleavage, substrate cleavage, and cytochrome c release.

Main Results:

  • Caspase-3 efficiently cleaves caspases-9 and -2 in cell-free systems.
  • In intact cells, caspase-3 enhances cleavage of caspases-8 and -9, but not caspase-2.
  • Caspase-3 mediated feedback increases substrate cleavage and cytochrome c release, indicating enhanced apoptosis.

Conclusions:

  • Caspase-3 acts as an effector caspase and also amplifies apical caspase activation.
  • Caspase-3 plays a crucial role in crosstalk between apoptotic pathways.
  • Modulating caspase-3 activity could be a strategy to overcome cancer drug resistance.

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