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Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes
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The role of caspases in methotrexate-induced gastrointestinal toxicity

H T Papaconstantinou1, C Xie, W Zhang

  • 1Department of Surgery, University of Texas Medical Branch, Galveston, TX 77555-0542, USA.

Surgery
|October 31, 2001
PubMed
Abstract

Insights

Methotrexate chemotherapy causes gut apoptosis by activating specific caspases (cell-death proteins) in intestinal cells. Inhibiting these caspases may reduce chemotherapy-induced enterocolitis.

Area of Science:

  • Cell biology
  • Molecular mechanisms of apoptosis
  • Gastrointestinal oncology

Background:

  • Methotrexate chemotherapy is limited by enterocolitis, a major toxicity.
  • Methotrexate induces gut mucosal apoptosis, but the molecular mechanisms are unclear.
  • Caspases are key proteases involved in apoptosis, activated in a stimulus-specific manner.

Purpose of the Study:

  • Establish an in vitro model for methotrexate-induced gut apoptosis.
  • Determine the role of caspases in this process within intestinal epithelial cells.

Main Methods:

  • Rat intestinal epithelial cells (RIE-1) were treated with methotrexate.
  • Apoptosis was assessed via DNA fragmentation and nuclear staining.
  • Caspase activation was measured using fluorogenic substrates.
  • A general caspase inhibitor (ZVAD-fluoromethyl ketone) was used to assess caspase involvement.

Main Results:

  • Methotrexate induced apoptosis and reduced cell number in RIE-1 cells.
  • Sequential activation of caspases 9, 2, and 3 was observed.
  • Caspases 1 and 8 remained inactive.
  • ZVAD-fluoromethyl ketone significantly inhibited methotrexate-induced apoptosis and caspase activation.

Conclusions:

  • Methotrexate activates specific caspases, leading to apoptosis in intestinal epithelial cells.
  • Caspases play a crucial role in methotrexate-induced apoptosis.
  • Targeting caspases could be a therapeutic strategy to mitigate methotrexate-induced enterocolitis.

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