L3MBTL3 and STAT3 collaboratively upregulate SNAIL expression to promote metastasis in female breast cancer

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Signal transducer and activator of transcription 3 (STAT3) pathway activation is crucial for cancer progression, promoting epithelial-mesenchymal transition (EMT), migration, invasion, and metastasis.
• STAT3 enhances SNAIL transcription, a key EMT regulator, independently of DNA binding, but the recruitment mechanism remains unclear.

Purpose of the Study:

• To elucidate the mechanism by which STAT3 is recruited to the SNAIL promoter.
• To investigate the role of lysine methylation binding protein L3MBTL3 in STAT3-mediated SNAIL upregulation and breast cancer metastasis.

Main Methods:

• Investigated the association between L3MBTL3 expression and clinical outcomes in breast cancer patients.
• Performed mechanistic studies to identify interactions between L3MBTL3, STAT3, and the SNAIL promoter.
• Assessed the functional impact of L3MBTL3-STAT3 interaction on SNAIL transcription and breast cancer metastasis.

Main Results:

• L3MBTL3 expression correlates positively with metastasis and poor prognosis in female breast cancer patients.
• L3MBTL3 interacts with STAT3 and facilitates its recruitment to the SNAIL promoter, increasing SNAIL transcription.
• L3MBTL3-STAT3 interaction is essential for promoting SNAIL upregulation and metastasis, independent of L3MBTL3's methylated lysine binding activity.

Conclusions:

• L3MBTL3 acts as a scaffold protein, recruiting STAT3 to the SNAIL promoter to drive breast cancer metastasis.
• L3MBTL3 and STAT3 synergistically enhance SNAIL expression, representing a potential therapeutic target for metastatic breast cancer.