Go to JCI Insight
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Journal stats
  • Publication ethics
  • Publication alerts by email
  • Advertising
  • Job board
  • Contact
  • Clinical Research and Public Health
  • Current issue
  • Past issues
  • By specialty
    • COVID-19
    • Cardiology
    • Gastroenterology
    • Immunology
    • Metabolism
    • Nephrology
    • Neuroscience
    • Oncology
    • Pulmonology
    • Vascular biology
    • All ...
  • Videos
    • ASCI Milestone Awards
    • Video Abstracts
    • Conversations with Giants in Medicine
  • Reviews
    • View all reviews ...
    • Emerging therapeutic strategies in breast cancer (Oct 2026)
    • The cGAS-STING pathway: DNA sensing in health and disease (Jun 2026)
    • Neurodegeneration (Mar 2026)
    • Clinical innovation and scientific progress in GLP-1 medicine (Nov 2025)
    • Pancreatic Cancer (Jul 2025)
    • Complement Biology and Therapeutics (May 2025)
    • Evolving insights into MASLD and MASH pathogenesis and treatment (Apr 2025)
    • View all review series ...
  • Viewpoint
  • Collections
    • In-Press Preview
    • Clinical Research and Public Health
    • Research Letters
    • Letters to the Editor
    • Editorials
    • Commentaries
    • Editor's notes
    • Reviews
    • Viewpoints
    • 100th anniversary
    • Top read articles

  • Current issue
  • Past issues
  • Specialties
  • Reviews
  • Review series
  • ASCI Milestone Awards
  • Video Abstracts
  • Conversations with Giants in Medicine
  • In-Press Preview
  • Clinical Research and Public Health
  • Research Letters
  • Letters to the Editor
  • Editorials
  • Commentaries
  • Editor's notes
  • Reviews
  • Viewpoints
  • 100th anniversary
  • Top read articles
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Journal stats
  • Publication ethics
  • Publication alerts by email
  • Advertising
  • Job board
  • Contact

Submit a comment

Combined inhibition of DNA Polymerase Theta and ATR targets MYBL2-high triple-negative breast cancer stem cells
Rachel Bayley, Xiaoping Qu, Adrija Chakraborty, Menna Shamma, Ciara Ward, Kinga Koscielniak, Anna Munsey, Suman Ahmed, Amber Stiby, Bohdana-Myroslava Briantseva, Kirendeep Jawanda, Christopher J. Lord, Abeer M. Shaaban, Marco Saponaro, Graeme C. M. Smith, Robert B. Clarke, Clare Davies, Paloma Garcia
Rachel Bayley, Xiaoping Qu, Adrija Chakraborty, Menna Shamma, Ciara Ward, Kinga Koscielniak, Anna Munsey, Suman Ahmed, Amber Stiby, Bohdana-Myroslava Briantseva, Kirendeep Jawanda, Christopher J. Lord, Abeer M. Shaaban, Marco Saponaro, Graeme C. M. Smith, Robert B. Clarke, Clare Davies, Paloma Garcia
View: Text | PDF
Research In-Press Preview Cell biology Genetics Oncology

Combined inhibition of DNA Polymerase Theta and ATR targets MYBL2-high triple-negative breast cancer stem cells

  • Text
  • PDF
Abstract

Triple negaJve breast cancer (TNBC) is characterised by poor prognosis and limited treatment opJons, parJally due to therapy-resistant stem/progenitor cells driving metastasis. Elevated expression of the transcripJon factor MYBL2 is associated with aggressive disease, yet its role in BC stem/progenitor cells remains elusive. Here, we employed inducible MYBL2 downregulaJon in TNBC cell lines and paJent-derived models to invesJgate its funcJon and idenJfy potenJal vulnerabiliJes associated with its high expression. Our funcJonal and mechanisJc analyses reveal that high MYBL2 levels are criJcal for stem cell self-renewal, DNA repair, and replicaJon stress response and lowering MYBL2 impairs stemness and self-renewal both in vitro and in vivo. Accordingly, high-MYBL2 stem/progenitor cells exhibit increased sensiJvity to Polθ inhibitors which is lost upon MYBL2 downregulaJon due to transcripJonal suppression. Combining Polθ inhibitors with ATR inhibitors further enhances this sensiJvity, in vitro, ex vivo and in vivo. These findings suggest that dual Polθ/ATR inhibiJon represents a promising therapeuJc strategy to target TNBC stem/progenitor cells with high MYBL2 expression, highlighJng MYBL2 as a potenJal biomarker to straJfy paJents for Polθ inhibitor-based therapies in TNBC.

Authors

Rachel Bayley, Xiaoping Qu, Adrija Chakraborty, Menna Shamma, Ciara Ward, Kinga Koscielniak, Anna Munsey, Suman Ahmed, Amber Stiby, Bohdana-Myroslava Briantseva, Kirendeep Jawanda, Christopher J. Lord, Abeer M. Shaaban, Marco Saponaro, Graeme C. M. Smith, Robert B. Clarke, Clare Davies, Paloma Garcia

×

Guidelines

The Editorial Board will only consider comments that are deemed relevant and of interest to readers. The Journal will not post data that have not been subjected to peer review; or a comment that is essentially a reiteration of another comment.

  • Comments appear on the Journal’s website and are linked from the original article’s web page.
  • Authors are notified by email if their comments are posted.
  • The Journal reserves the right to edit comments for length and clarity.
  • No appeals will be considered.
  • Comments are not indexed in PubMed.

Specific requirements

  • Maximum length, 400 words
  • Entered as plain text or HTML
  • Author’s name and email address, to be posted with the comment
  • Declaration of all potential conflicts of interest (even if these are not ultimately posted); see the Journal’s conflict-of-interest policy
  • Comments may not include figures
This field is required
This field is required
This field is required
This field is required
This field is required
This field is required

Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)

Sign up for email alerts