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Visualizing and Quantifying Endonuclease-Based Site-Specific DNA Damage
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Visualizing and Quantifying Endonuclease-Based Site-Specific DNA Damage

Published on: August 21, 2021

Depletion of deoxyribonucleotide pools is an endogenous source of DNA damage in cells undergoing oncogene-induced

Sudha Mannava1, Kalyana C Moparthy, Linda J Wheeler

  • 1Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.

The American Journal of Pathology
|December 19, 2012
PubMed

Insights

Deoxyribonucleotide depletion causes DNA damage and oncogene-induced senescence (OIS). Restoring deoxyribonucleoside levels suppresses OIS, revealing a novel role for deoxyribonucleotides in this process.

Area of Science:

  • Cellular Biology
  • Molecular Biology
  • Cancer Research

Background:

  • Oncogene-induced senescence (OIS) is a tumor-suppressive mechanism dependent on DNA damage response.
  • Oxidative stress and DNA hyperreplication are known OIS triggers.
  • The role of deoxyribonucleotide pools in OIS remains unclear.

Purpose of the Study:

  • To investigate the role of deoxyribonucleotide pools in oncogene-induced senescence.
  • To identify endogenous sources of DNA damage during OIS.

Main Methods:

  • Assessed deoxyribonucleotide levels and DNA damage in normal human fibroblasts (NHFs) expressing HRAS(G12V).
  • Quantified thymidylate synthase (TS) and ribonucleotide reductase (RR) expression.
  • Analyzed chromatin modifications at TS and RR gene promoters.
  • Manipulated TS and RR expression and deoxyribonucleoside levels.

Main Results:

  • NHF-HRAS(G12V) cells exhibited decreased TS and RR expression, leading to low deoxyribonucleotide triphosphate (dNTP) levels and DNA damage.
  • Chromatin changes at TS and RR promoters were associated with gene silencing.
  • Restoring TS/RR or adding deoxyribonucleosides reduced DNA damage and OIS phenotypes.
  • Suppression of TS/RR induced DNA damage and senescence in NHFs.

Conclusions:

  • Deoxyribonucleotide pool depletion is a significant endogenous source of DNA damage in OIS.
  • OIS requires dNTP depletion and active DNA replication, distinguishing it from quiescence.
  • Deoxyribonucleotides play a critical, previously unrecognized role in regulating OIS.

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