The Role of MicroRNA-429 in E2F3 Expression in Breast Cancer Cell Lines

Background and purpose: MicroRNA regulation of cancer-related pathways has a major effect on cancer development. MiR-429 is a member of miR-200 family with an important role in metastasis. There are many studies on the association between miR-429 and liver, bladder, bowel, and gastric cancers. In this study, we investigated the expression changes of E2F3 genes after transfection of MCF-7 cells using pre-miR-429 and anti-miR-429 as the potential targets of miR-429. In this experimental study, E2F3 was predicted as the potential target of miR-429 using using miRNA bioinformatics tools. MCF-7 cells were then transfected with both mir-429 precursor and inhibitory vectors. RNA extraction and cDNA synthesis were done after 48 hr. Expression of miR-429 and target gene were determined by qRT-PCR. The comparison between the results of untransfected cells group, transfected with pre-miR-429 group, and transfected with anti-miR-429 group showed that down-regulation of miR-429, increased the expression level of E2F3 in cells transfected with miR-429 inhibitory vector (9.38 folds). Expression level of E2F3 decreased in cells transfected with pre-miR-429 vector (5.3 folds). Low expression level of miR-429 in breast cancer was found to be effective in bone metastasis, although in ovarian cancer and colorectal carcinoma, resulted in decreasing invasion and matastasis. In current study, the expression level of E2F3 decreased when transfected with pre-miR-429 vector and increased when transfected with anti-miR-429 vector, therefore, miR-429 could be a potential target in breast cancer therapy.