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Updated: May 3, 2026

Characterize Disease-related Mutants of RAF Family Kinases by Using a Set of Practical and Feasible Methods
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Wild-type H- and N-Ras promote mutant K-Ras-driven tumorigenesis by modulating the DNA damage response

Elda Grabocka1, Yuliya Pylayeva-Gupta1, Mathew J K Jones2

  • 1Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA.

Cancer Cell
|February 15, 2014
PubMed

Insights

Wild-type Ras proteins can promote KRAS-driven cancers. Downregulating them sensitizes cancer cells to chemotherapy by inhibiting DNA damage checkpoints.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cancer Genetics

Background:

  • KRAS mutations are common in human cancers and confer resistance to therapies.
  • While activating mutations grant RAS genes autonomy, wild-type RAS forms may fuel mutant RAS-driven tumorigenesis.

Purpose of the Study:

  • To investigate the role of wild-type H-Ras and N-Ras in mutant K-Ras cancer cells.
  • To determine if modulating wild-type Ras impacts cancer cell sensitivity to DNA damage chemotherapeutics.

Main Methods:

  • Downregulation of wild-type H-Ras or N-Ras in mutant K-Ras cancer cells.
  • Analysis of Erk/p90RSK and PI3K/Akt pathway activation.
  • Assessment of Chk1 phosphorylation at Ser 280.
  • Evaluation of ATR/Chk1 signaling and G2 DNA damage checkpoint activation.
  • Testing sensitivity to DNA damage chemotherapeutic agents in vitro and in vivo.

Main Results:

  • Downregulation of wild-type H-Ras or N-Ras led to hyperactivation of Erk/p90RSK and PI3K/Akt pathways.
  • This resulted in inhibitory phosphorylation of Chk1 at Ser 280.
  • ATR/Chk1 signaling inhibition abrogated the G2 DNA damage checkpoint.
  • Mutant K-Ras cancer cells showed specific sensitization to DNA damage chemotherapeutics.

Conclusions:

  • Wild-type H-Ras and N-Ras play a crucial role in maintaining the G2 DNA damage checkpoint in mutant K-Ras cancers.
  • Targeting wild-type Ras could be a therapeutic strategy to sensitize KRAS-mutant cancers to DNA-damaging agents.

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