Reactive oxygen species and mitochondrial sensitivity to oxidative stress determine induction of cancer cell death by p21

Ionica Masgras, Samantha Carrera, Petra J. De Verdier, Paul Brennan, Aneela Majid, Wan Makhtar, Eugene Tulchinsky, George D.D. Jones, Igor B. Roninson, Salvador Macip

Research output: Contribution to journalArticlepeer-review

61 Citations (Scopus)


p21 Waf1/Cip1/Sdi1 is a cyclin-dependent kinase inhibitor that mediates cell cycle arrest. Prolonged p21 up-regulation induces a senescent phenotype in normal and cancer cells, accompanied by an increase in intracellular reactive oxygen species (ROS). However, it has been shown recently that p21 expression can also lead to cell death in certain models. The mechanisms involved in this process are not fully understood. Here, we describe an induction of apoptosis by p21 in sarcoma cell lines that is p53-independent and can be ameliorated with antioxidants. Similar levels of p21 and ROS caused senescence in the absence of significant death in other cancer cell lines, suggesting a cell-specific response. We also found that cells undergoing p21-dependent cell death had higher sensitivity to oxidants and a specific pattern of mitochondrial polarization changes. Consistent with this, apoptosis could be blocked with targeted expression of catalase in the mitochondria of these cells. We propose that the balance between cancer cell death and arrest after p21 up-regulation depends on the specific effects of p21- induced ROS on the mitochondria. This suggests that selective up-regulation of p21 in cancer cells could be a successful therapeutic intervention for sarcomas and tumors with lower resistance to mitochondrial oxidative damage, regardless of p53 status.

Original languageEnglish
Pages (from-to)9845-9854
Number of pages10
JournalJournal of Biological Chemistry
Issue number13
Publication statusPublished - Mar 23 2012
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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