Background
To assess the effect of microRNA-126-5p (miR-126-5p) on the migration of the breast cancer MCF7 cell line.
Conclusion
Upregulation of miR-126-5p can inhibit the migration of the breast cancer MCF7 cell line, which may involve its direct targeting of the 3'UTR of CNOT7.
Methods
GSE143564 was downloaded from the Gene Expression Omnibus (GEO; http://www.ncbi.nlm.nih.gov/geo) to identify the differentially expressed miRNAs between breast cancer and adjacent tissues. Quantitative reverse transcription PCR (RT-qPCR) was used to assess miR-126-5p levels in the normal 184A1 breast cell line and the breast cancer MCF7 cell line. The MCF7 cell line was then transfected with miR-126-5p mimics or corresponding negative control (NC-mimic). The proliferation and migration abilities of the MCF7 cell line were measured by methyl thiazolyl tetrazolium (MTT), Transwell and scratch healing assays. CCR4-NOT transcription complex and subunit 7 (CNOT7) expression levels in the NC-mimic and miR-126-5p mimic groups were measured by Western blot analysis. Bioinformatic analysis and a dual-luciferase reporter assay were performed to identify the miR-126-5p target gene.
Results
One hundred forty-eight differentially expressed miRNAs (downregulated = 55, upregulated = 93) were identified. MiR-126-5p expression in the MCF7 cell line was significantly downregulated relative to that of 184A1 cell line (P < 0.05). Compared with that observed in the control and NC-mimic groups, cell proliferation in the miR-126-5p mimic group was significantly decreased at 48 and 72 h posttransfection (P < 0.05). In addition, the scratch healing rate and number of membrane-piercing cells in the miR-126-5p overexpression group were lower than those detected in the control and NC groups (P < 0.05). Furthermore, miR-126-5p could reduce the luciferase activity for the wild-type CNOT7 gene 3'-untranslated region (UTR) reporter (P < 0.05) but had no effect on the mutant 3'UTR reporter (P > 0.05). Compared with that observed in the NC and control groups, the levels of CNOT7 in the miR-126-5p overexpression group decreased (P < 0.05).