BMI1 as a Potential Target of miR-330-3p in Colorectal Cancer

 Colorectal cancer (CRC) is one of the most common cancers worldwide. CRC therapy is still a serious problem because of the presence of cancer stem cells (CSCs) within the tumor. BMI1 (B lymphoma Mo-MLV insertion region 1 homolog) is one of the important molecules for self-renewal of the CSCs and a component of poly comb repressive complex 1 that plays an important role in stimulating the progression of the cell cycle through epigenetic inhibition of tumor suppressors. BMI1 is a marker of colon stem cells that its expression increases in colorectal CSCs. The inhibition of BMI1 expression by miRNA could be one of the promising treatment options in CRC. Furthermore, investigating the regulation of BMI1 expression by miRNAs during tumorigenesis could be valuable in the identification of molecular mechanisms involved in CRC. Our aim was to conduct a bioinformatics analysis of known tumor suppressor miRNAs in CRC that have a potential to inhibit BMI1 expression.

 The presence of BMI-1, as a potential target of the selected miRNAs, was explored in various databases of miRNA target prediction including TargetScan, DIANA-microT, PicTar, miRanada, miRtar, mirMAP, and miRDB. These databases are based on algorithms such as miRNA-target interactions and thermodynamic stability (ΔG). miRNA with the highest score was selected according to the prediction score.

 According to bioinformatics analysis, the highest score was derived for miR-330-3p. As a new miRNA to suppress BMI-1, miR-330-3p can be used in applied studies.

 Compared to other tumor suppressor miRNAs in CRC, miR-330-3p has the greatest probability to inhibit BMI1. Therefore, the experimental validation of miR-330-3p/BMI1 axis would be useful in identifying novel therapeutics and biomarkers in CRC.