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Updated: May 8, 2026

Analysis of Cell Cycle Position in Mammalian Cells
12:19

Analysis of Cell Cycle Position in Mammalian Cells

Published on: January 21, 2012

G2-to-G0 cell cycle exit underlies sensitivity to ATR inhibition via the p53-p21-RB1 axis

Celina Sanchez, Carlos Origel Marmolejo, Juyoung Lee

    Biorxiv : the Preprint Server for Biology
    |May 7, 2026
    PubMed

    Insights

    Cancer cells rely on ATR for survival, but responses to ATR inhibitors vary. Inhibiting MDM2 can overcome resistance by lowering the DNA damage threshold, making it a promising therapeutic target for breast cancer treatment.

    Area of Science:

    • Molecular biology
    • Cancer research
    • Cell cycle regulation

    Background:

    • Ataxia-telangiectasia and Rad3-related (ATR) kinase is crucial for DNA damage response and genome integrity.
    • Cancer cells' hyper-proliferation makes them dependent on ATR, positioning ATR inhibitors as potential therapeutics.
    • Variable tumor responses to ATR inhibitors necessitate understanding cell fate determinants.

    Purpose of the Study:

    • To investigate breast cancer sensitivity to ATR inhibition.
    • To identify mechanisms driving cell fate under ATR inhibition.
    • To explore MDM2 as a target to enhance ATR inhibitor efficacy.

    Main Methods:

    • Analysis of breast cancer cell sensitivity to ATR inhibition.
    • Investigation of the p53-p21-RB1 axis in cell cycle regulation.
    • Assessment of MDM2 inhibition's effect on ATR inhibitor resistance.

    Main Results:

    • Breast cancer sensitivity to ATR inhibition correlates with pan-nuclear DNA damage.
    • A p53-p21-RB1 axis drives G2-to-G0-like cell cycle exit.
    • MDM2 inhibition lowers the DNA damage threshold, targeting ATR inhibitor-resistant cells.
    • Cell cycle plasticity determines cell fate during ATR inhibition.

    Conclusions:

    • ATR inhibitors show promise but face variable responses in cancer treatment.
    • MDM2 inhibition can overcome ATR inhibitor resistance by modulating cell cycle exit.
    • Targeting MDM2 presents a strategy to improve ATR inhibitor efficacy in breast cancer.

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