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Updated: Aug 12, 2026

Induction and Validation of Cellular Senescence in Primary Human Cells
08:18

Induction and Validation of Cellular Senescence in Primary Human Cells

Published on: June 20, 2018

Inhibition of p21-mediated ROS accumulation can rescue p21-induced senescence

Salvador Macip1, Makoto Igarashi, Li Fang

  • 1Derald H.Ruttenberg Cancer Center, Mount Sinai School of Medicine, One Gustave L.Levy Place, Box 1130, New York, NY 10029, USA.

The EMBO Journal
|May 1, 2002
PubMed

Insights

The cyclin-dependent kinase (CDK) inhibitor p21 causes permanent cell growth arrest by increasing reactive oxygen species (ROS). This ROS increase is essential for p21-induced senescence and does not require p21

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Oncology

Background:

  • Senescence is a state of permanent cell cycle arrest.
  • Reactive oxygen species (ROS) can induce senescence-like growth arrest.
  • p21(Waf1/Cip1/Sdi1) is a known inducer of senescence.

Purpose of the Study:

  • To investigate the role of ROS in p21-induced senescence.
  • To determine if ROS accumulation is necessary for p21-mediated permanent growth arrest.
  • To elucidate the mechanism of p21-induced senescence, independent of CDK inhibition or PCNA binding.

Main Methods:

  • Measuring intracellular ROS levels in cells treated with p21.
  • Using N-acetyl-L-cysteine to inhibit ROS and assess rescue of senescence.
  • Comparing the effects of p21 with p16(Ink4a) on ROS levels and growth arrest reversibility.
  • Utilizing a p21 mutant lacking PCNA binding capability.

Main Results:

  • p21 significantly increased intracellular ROS levels in both normal fibroblasts and p53-negative cancer cells.
  • Inhibition of ROS by N-acetyl-L-cysteine prevented p21-induced senescence, confirming ROS necessity.
  • p16(Ink4a) did not increase ROS levels, and its induced cell cycle arrest was reversible.
  • A p21 mutant unable to bind PCNA still induced ROS and permanent growth arrest.

Conclusions:

  • p21 mediates senescence through a mechanism involving ROS accumulation.
  • ROS elevation is a critical and necessary step for p21-induced permanent growth arrest.
  • This p21-driven senescence mechanism is independent of its CDK inhibitory functions and PCNA binding ability.

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