Related Experiment Video
Updated: Feb 15, 2026
Isolation and Functional Assessment of Human Breast Cancer Stem Cells from Cell and Tissue Samples
Published on: October 2, 2020
SALL4 - KHDRBS3 network enhances stemness by modulating CD44 splicing in basal-like breast cancer
Yoshiaki Matsumoto1, Junji Itou1, Fumiaki Sato1
1Department of Breast Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Abstract:
Understanding the mechanism by which cancer cells enhance stemness facilitates cancer therapies. Here, we revealed that a stem cell transcription factor, SALL4, functions to enhance stemness in basal-like breast cancer cells. We used shRNA-mediated knockdown and gene overexpression systems to analyze gene functions. To evaluate stemness, we performed a sphere formation assay. In SALL4 knockdown cells, the sphere formation ability was reduced, indicating that SALL4 enhances stemness. CD44 is a membrane protein and is known as a stemness factor in cancer. CD44 splicing variants are involved in cancer stemness. We discovered that SALL4 modulates CD44 alternative splicing through the upregulation of KHDRBS3, a splicing factor for CD44. We cloned the KHDRBS3-regulated CD44 splicing isoform (CD44v), which lacks exons 8 and 9. CD44v overexpression prevented a reduction in the sphere formation ability by KHDRBS3 knockdown, indicating that CD44v is positively involved in cancer stemness. In addition, CD44v enhanced anoikis resistance under the control of the SALL4 - KHDRBS3 network. Basal-like breast cancer is an aggressive subtype among breast cancers, and there is no effective therapy so far. Our findings provide molecular targets for basal-like breast cancer therapy. In the future, this study may contribute to the establishment of drugs targeting cancer stemness.
Insights
Stem cell transcription factor SALL4 enhances stemness in basal-like breast cancer by upregulating KHDRBS3, which modulates CD44 splicing. This SALL4-KHDRBS3-CD44v pathway offers potential therapeutic targets for aggressive breast cancer.
Area of Science:
- Molecular Biology
- Cancer Research
- Cell Biology
Background:
- Cancer stemness is a key driver of tumor progression and therapeutic resistance.
- Basal-like breast cancer is an aggressive subtype with limited treatment options.
- Understanding the regulatory mechanisms of cancer stemness is crucial for developing novel therapies.
Purpose of the Study:
- To elucidate the role of stem cell transcription factor SALL4 in basal-like breast cancer stemness.
- To identify the downstream effectors and molecular mechanisms by which SALL4 enhances stemness.
- To explore the potential of targeting the SALL4 pathway for basal-like breast cancer treatment.
Main Methods:
- shRNA-mediated knockdown and gene overexpression systems were employed to analyze gene functions.
- Sphere formation assays were utilized to evaluate cancer stemness.
- Analysis of CD44 alternative splicing and its regulation by SALL4 and KHDRBS3 was performed.
Main Results:
- SALL4 was identified as a crucial factor that enhances stemness in basal-like breast cancer cells, as evidenced by reduced sphere formation upon SALL4 knockdown.
- SALL4 upregulates KHDRBS3, a splicing factor that modulates CD44 alternative splicing, leading to the production of CD44 variants (CD44v) lacking exons 8 and 9.
- Overexpression of CD44v rescued the sphere formation defect caused by KHDRBS3 knockdown and enhanced anoikis resistance, highlighting its role in cancer stemness and survival under the SALL4-KHDRBS3 network.
Conclusions:
- SALL4 plays a significant role in promoting cancer stemness in basal-like breast cancer through the KHDRBS3-mediated regulation of CD44 splicing.
- The identified SALL4-KHDRBS3-CD44v axis represents a promising molecular target for developing new therapeutic strategies against aggressive basal-like breast cancer.
- Targeting cancer stemness pathways, such as the one involving SALL4, holds potential for future drug development in oncology.
Related Concept Videos
02:18Alternative RNA Splicing
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
02:18Alternative RNA Splicing
01:32RNA Splicing
02:26Protein Networks
These interactions can be represented through maps depicting protein-protein interaction networks, represented as nodes and edges. Nodes are circles that are representative of a protein,...
02:18Network Covalent Solids
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
00:55Laminins are the Adhesive Proteins of Basal Lamina
In humans, the five forms of alpha chains are LAMA 1, LAMA 2, LAMA 3, LAMA 4, and LAMA 5. The four forms of beta chains are LAMB 1, LAMB 2, LAMB 3, and LAMB 4. The three forms of gamma...