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Updated: Jan 16, 2026
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Studying TGF-β Signaling and TGF-β-induced Epithelial-to-mesenchymal Transition in Breast Cancer and Normal Cells
Published on: October 27, 2020
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A STAT1-GBP1 axis modulates epithelial proliferation in postpartum breast tissue by repressing CDKI expression
Joshua W Ogony1, Laura M Pacheco-Spann2, Amanda Arnold3
1Department of Cancer Biology, Mayo Clinic, 4500 San Pablo Road S, Jacksonville, FL, 32224, USA.
Breast Cancer Research : BCR
|September 26, 2025
Summary
A postpartum interferon signature involving signal transducer and activator of transcription 1 (STAT1) and guanylate binding protein 1 (GBP1) promotes breast cell proliferation by suppressing cell cycle inhibitors. This may explain increased postpartum breast cancer risk.
Area of Science:
- Oncology
- Molecular Biology
- Immunology
Background:
- Postpartum breast cancer has higher mortality than in nulliparous women.
- Molecular drivers of postpartum breast cancer remain unclear.
- Investigated STAT1 and GBP1's role in postpartum epithelial proliferation via CDKI suppression.
Purpose of the Study:
- To investigate the role of STAT1 and GBP1 in postpartum breast epithelial cell proliferation.
- To determine if STAT1 and GBP1 suppress cyclin-dependent kinase inhibitors (CDKIs).
Main Methods:
- Compared postpartum and nulliparous benign breast tissues using transcriptomic profiling.
- Examined STAT1, GBP1, and Ki67 protein expression via immunohistochemistry.
- Utilized siRNA and lentiviral knockdown in human mammary epithelial cells (HMECs) to assess CDKI expression, cell cycle, and proliferation.
Main Results:
- Postpartum tissues showed an interferon signature (STAT1, GBP1), elevated Ki67, and reduced CDKIs.
- STAT1/GBP1 knockdown in HMECs increased p21/p57, induced G1 arrest, and reduced proliferation.
- GBP1 mediates the STAT1-Ki67 link; STAT1 and GBP1 cooperatively suppress proliferation.
Conclusions:
- Identified a STAT1-GBP1 axis that enhances postpartum epithelial proliferation by repressing CDKIs.
- This mechanism may explain increased postpartum breast cancer vulnerability.
- Highlights potential biomarkers and early intervention targets for postpartum breast tissues.
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