Bioinformatics Prediction and In Vitro Analysis Revealed That miR-17 Targets Cyclin D1 mRNA in Triple Negative Breast Cancer Cells

Breast cancer is one of the most prevalent malignancies among women worldwide. Triple negative breast cancer (TNBC) is a type of breast cancer in which estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER-2) are not expressed. There is no targeted therapy for this type of cancer, and available therapies have poor therapeutic effects. Performing a preliminary research, we selected cyclin D1 (CCND1) gene of Wnt signaling pathway which is a target of miRNAs, a promising set of biomolecules in diagnosis and treatment of breast cancer. In this study using bioinformatic analyses, miR-17 was selected as it targets the 3'UTR of CCND1 gene with the highest score. Luciferase assay results also confirmed the bioinformatic prediction. Decreased expression of miR-17 in MDA-MB-231 cell line was observed using qRT-PCR method. After lentiviral transduction of miR-17 to the target cells, gene expression analysis showed decreased expression of CCND1 gene. We found miR-17 as an attractive molecule that after intensive research can probably be used as a biomarker in TNBC.