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Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation
08:47

Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation

Published on: March 5, 2018

Caspase-mediated Cdk2 activation is a critical step to execute transforming growth factor-beta1-induced apoptosis in

S G Kim1, S N Kim, H S Jong

  • 1Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-744, Korea.

Oncogene
|April 21, 2001
PubMed

Insights

Transforming growth factor-beta1 (TGF-β1) induces apoptosis in gastric cancer cells by activating caspase-3. This caspase cleaves cell cycle proteins, leading to aberrant Cdk2 activation and cell death.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Cancer Research

Background:

  • Transforming growth factor-beta1 (TGF-β1) is a known growth inhibitor that can also induce apoptosis.
  • The precise molecular mechanisms underlying TGF-β1-induced apoptosis remain largely undefined.

Purpose of the Study:

  • To elucidate the mechanism of TGF-β1-induced apoptosis in SNU-16 human gastric cancer cells.
  • To identify the key molecular players and pathways involved in this process.

Main Methods:

  • Cell cycle analysis and TUNEL assay to assess cell cycle progression and apoptosis.
  • Western blotting and caspase activity assays to evaluate protein cleavage and enzyme activation.
  • Inhibition of Cdk2 and caspase-3 activities to determine their roles in apoptosis.

Main Results:

  • TGF-β1 treatment induced G1 cell cycle arrest followed by apoptosis.
  • Caspase-3 activation occurred concurrently with G1 arrest and was responsible for cleaving p21(cip1), p27(kip1), and Rb.
  • Cleavage of p21 and p27 led to aberrant Cdk2 activation, which was essential for TGF-β1-induced apoptosis.
  • Inhibition of Cdk2 blocked apoptosis but not caspase-3 activation, while caspase-3 inhibition prevented Cdk2 activation and apoptosis.

Conclusions:

  • TGF-β1-induced apoptosis involves caspase-3 activation, which initiates the transition from G1 arrest to apoptosis.
  • Cleavage of cell cycle regulators (p21, p27, Rb) by caspase-3 leads to Cdk2 activation.
  • Cdk2 activation downstream of caspase-3 is a critical execution step for TGF-β1-induced apoptosis in gastric cancer cells.

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