TLE3 Sustains Luminal Breast Cancer Lineage Fidelity to Suppress Metastasis

Area of Science:

• Molecular biology
• Cancer research
• Cell biology

Background:

• Breast cancer subtypes exhibit phenotypes mirroring mammary epithelial cell development.
• Understanding lineage identity mechanisms is crucial for mitigating breast cancer progression.

Purpose of the Study:

• To investigate the role of transcriptional corepressor TLE3 in maintaining luminal breast cancer cell fate.
• To explore TLE3's function independently of the estrogen receptor.

Main Methods:

• Analysis of TLE3's transcriptional repression activity.
• Investigation of TLE3's interaction with FOXA1.
• Assessment of TLE3's impact on gene expression signatures associated with basal-like breast cancer (BLBC).

Main Results:

• TLE3 acts as a guardian of luminal cell fate in breast cancer.
• TLE3 represses gene expression signatures of aggressive basal-like breast cancers (BLBC), including SOX9 and TGFβ2.
• TLE3 localization, mediated by FOXA1, is essential for maintaining the luminal lineage.
• TLE3 prevents the acquisition of a hybrid epithelial-mesenchymal state, reducing metastatic capacity.

Conclusions:

• TLE3 is an essential transcriptional repressor sustaining the differentiated, less metastatic nature of luminal breast cancers.
• Targeting TLE3 expression could promote less aggressive disease states and improve patient survival.