miR-3140 suppresses tumor cell growth by targeting BRD4 via its coding sequence and downregulates the BRD4-NUT fusion...

Area of Science:

• Molecular Biology
• Oncology
• Gene Regulation

Background:

• Bromodomain Containing 4 (BRD4) is crucial for oncogene MYC transcription and tumorigenesis.
• NUT midline carcinoma (NMC) is a rare, lethal cancer driven by the BRD4-NUT fusion gene.
• MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression.

Purpose of the Study:

• To identify novel tumor-suppressive miRNAs.
• To investigate the role of miR-3140 in cancer, particularly its interaction with BRD4.
• To evaluate miR-3140 as a potential cancer therapeutic.

Main Methods:

• Function-based screening of a miRNA mimic library.
• Direct binding assays to validate miRNA-target interactions (BRD4, BRD3, CDK2, EGFR).
• In vitro cell growth inhibition assays and in vivo xenograft mouse models.

Main Results:

• miR-3140 was identified as a novel tumor-suppressive miRNA.
• miR-3140 directly suppresses BRD4, BRD3, CDK2, and EGFR expression.
• miR-3140 inhibited tumor cell growth in various cancer cell lines, including EGFR inhibitor-resistant cells.
• miR-3140 downregulated the BRD4-NUT fusion protein and suppressed NMC cell growth.
• miR-3140 administration inhibited tumor growth in vivo.

Conclusions:

• miR-3140 directly targets and downregulates BRD4 and the BRD4-NUT fusion protein.
• miR-3140 exhibits potent anti-tumor activity in vitro and in vivo.
• miR-3140 represents a promising candidate for miRNA-based cancer therapeutics.