Molecular pathogenesis of triple-negative breast cancer based on microRNA expression signatures: antitumor miR-204-5p...

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Triple-negative breast cancer (TNBC) is an aggressive subtype with limited therapeutic options and poor patient outcomes.
• Identifying novel molecular targets is crucial for developing effective treatments for TNBC.

Purpose of the Study:

• To investigate the microRNA (miRNA) expression signature in TNBC clinical specimens.
• To elucidate the functional role of dysregulated miRNAs, particularly miR-204-5p, in TNBC progression.
• To identify and validate direct molecular targets of miR-204-5p involved in TNBC pathogenesis.

Main Methods:

• MicroRNA sequencing of TNBC clinical specimens to identify dysregulated miRNAs.
• Functional assays (e.g., cell migration, invasion) to assess the impact of miR-204-5p.
• Genome-wide gene expression analysis and in silico prediction to identify putative miRNA targets.
• Luciferase reporter assays to validate direct miRNA-target interactions.
• Analysis of downstream RNA networks regulated by identified targets.

Main Results:

• A significant miRNA expression signature was identified in TNBC, with 104 miRNAs dysregulated.
• miR-204-5p was markedly downregulated and its ectopic expression suppressed BC cell migration and invasion.
• AP1S3 was identified as a direct target of miR-204-5p, with its overexpression linked to poor prognosis and enhanced cancer aggressiveness in TNBC.
• Downstream RNA networks regulated by AP1S3 were further analyzed.

Conclusions:

• The identified miRNA signature provides insights into TNBC molecular mechanisms.
• miR-204-5p acts as a tumor suppressor by inhibiting cell migration and invasion, potentially through targeting AP1S3.
• AP1S3 is a potential therapeutic target in TNBC, and its regulation by miR-204-5p offers a novel therapeutic strategy.