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Utilizing Murine Inducible Telomerase Alleles in the Studies of Tissue Degeneration/Regeneration and Cancer
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Oxidative base damage to telomeres sensitizes cancer cells to ATR inhibition

Alex Garbouchian1, Natalia Cestari Moreno1, Aninda Dey1

  • 1Department of Cancer Biology, University of Kansas Medical Center, University of Kansas Cancer Center, Kansas City, KS, USA.

Communications Biology
|July 11, 2026
PubMed

Insights

Targeting telomere oxidative damage with ATR inhibitors enhances cancer cell death. This approach exploits cancer cell reliance on G2/M checkpoints, reducing viability without harming healthy cells.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Genetics

Background:

  • Cancer cells often inactivate the G1/S checkpoint, making them dependent on the G2/M checkpoint for survival under replication stress.
  • PARP inhibitors highlight the clinical success of targeting DNA damage response proteins.
  • Telomeres are crucial for genomic stability, and their damage can impact cancer cell fate.

Purpose of the Study:

  • To investigate the therapeutic potential of targeting telomeric oxidative damage in cancer.
  • To determine if inhibiting ATR, CHK1, or WEE1 enhances the cytotoxicity of induced telomeric 8-oxo-guanine.
  • To elucidate the underlying mechanisms of genome instability induced by this combination therapy.

Main Methods:

  • Induction of 8-oxo-guanine at telomeres in cancer cells.
  • Inhibition of ATR, CHK1, or WEE1 using specific pharmacological agents.
  • Assessment of cell viability, genome instability, and DNA replication stress.
  • Analysis of RPA levels and cell cycle progression.

Main Results:

  • A single induction of telomeric 8-oxo-guanine caused replication stress but was not cytotoxic.
  • Inhibition of ATR, CHK1, or WEE1 post-telomeric 8-oxo-guanine induction significantly reduced cancer cell viability.
  • This effect was observed at lower doses compared to non-cancerous cells, indicating selectivity.
  • The mechanism involves insufficient RPA for damaged telomeres, leading to premature G2/M exit and prolonged mitosis.

Conclusions:

  • Targeted oxidative base damage at telomeres can sensitize cancer cells to ATR inhibition.
  • This strategy enhances therapeutic efficacy by inducing genome instability selectively in cancer cells.
  • The findings support the development of novel cancer therapies targeting DNA damage response pathways.

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