TRF2 cooperates with CTCF for controlling the oncomiR-193b-3p in colorectal cancer

Area of Science:

• Molecular Biology
• Cancer Research
• Epigenetics

Background:

• Telomeric Repeat binding Factor 2 (TRF2) is crucial for telomere maintenance and implicated in cancer.
• TRF2's extratelomeric functions, including gene expression modulation, are increasingly recognized.
• MicroRNAs (miRNAs) are small non-coding RNAs frequently dysregulated in human tumors.

Purpose of the Study:

• To investigate the role of TRF2 in regulating miRNA expression in cancer.
• To identify specific miRNAs controlled by TRF2 and elucidate their functional consequences.
• To explore the mechanistic interplay between TRF2, CTCF, and miRNA regulation in colorectal cancer.

Main Methods:

• Analysis of The Cancer Genome Atlas (TCGA) dataset for TRF2 and miR-193b-3p correlation in colorectal cancer.
• Chromatin immunoprecipitation (ChIP) assays to identify TRF2 binding sites.
• Co-immunoprecipitation (Co-IP) assays to confirm protein-protein interactions between TRF2 and CTCF.
• Luciferase reporter assays to assess promoter activity and miRNA expression.
• Western blotting to evaluate protein levels of SUV39H1 and assess proliferation markers.

Main Results:

• TRF2 expression positively correlates with miR-193b-3p levels in colorectal cancer patients.
• TRF2 physically interacts with CTCF, facilitating TRF2 binding upstream of the miR-193b-3p host gene.
• TRF2-CTCF complex binding promotes miR-193b-3p expression, which inhibits SUV39H1 translation.
• Upregulation of miR-193b-3p by TRF2 promotes tumor cell proliferation.
• The TRF2-miR-193b-3p association demonstrates prognostic significance in patients.

Conclusions:

• TRF2, in cooperation with CTCF, directly regulates miR-193b-3p expression.
• The TRF2-miR-193b-3p axis functions as an oncogenic pathway by suppressing SUV39H1 and promoting proliferation.
• TRF2 and miR-193b-3p represent potential biomarkers for prognosis in colorectal cancer.