Integrin-Rac signalling for mammary epithelial stem cell self-renewal
Safiah Olabi1, Ahmet Ucar1, Keith Brennan1
1Wellcome Centre for Cell-Matrix Research and Manchester Breast Centre, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK.
Breast Cancer Research : BCR
|October 24, 2018
Summary
Integrins are crucial for mammary stem cell self-renewal. This study reveals integrin signaling activates Rac1 and Wnt pathways, essential for maintaining mammary stem cell populations.
Area of Science:
- Cell Biology
- Developmental Biology
- Stem Cell Research
Background:
- Mammary epithelial stem cells are precursors for all mammary cell types.
- Integrins, as extracellular matrix receptors, are vital for mammary epithelial development and function.
- Previous work established integrins' role in mammary epithelial cell survival, cell cycle, polarity, and gene expression.
Purpose of the Study:
- To investigate the role of integrins in mammary epithelial stem cell self-renewal.
- To elucidate the molecular mechanisms by which integrins influence mammary stem cell maintenance.
Main Methods:
- Utilized an in vitro stem cell assay with primary mouse mammary epithelial cells.
- Employed a 3D organoid assay to differentiate stem cell-driven (solid) and progenitor-driven (hollow) organoids.
Main Results:
- Demonstrated that integrins are essential for the maintenance and self-renewal of mammary epithelial stem cells.
- Showed that integrins activate the Rac1 signaling pathway in stem cells.
- Identified that Rac1 activation stimulates a Wnt pathway, leading to the expression of β-catenin target genes (e.g., Axin2, Lef1).
Conclusions:
- Integrin/Rac signaling is critical for mammary epithelial stem cell self-renewal.
- This signaling pathway specifies the activation of a canonical Wnt pathway necessary for stem cell maintenance.
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