Study on the exosome-mediated miR-18b-5p in promoting the proliferation, migration and invasion of breast cancer cells by regulating NEDD9

ObjectiveTo investigate the effects of miR-18b-5p on the invasion and migration of breast cancer cells by down-regulating the expression of neural precursor cell expressed developmentally down-regulated 9(NEDD9), and its mechanism.

MethodsThe expression levels of miR-18b-5p in human normal breast cancer epithelial cells MCF-10A and two breast cancer cell lines of SKBR-3 and SKBR-3/PR were detected using qRT-PCR.The surface markers of SKBR-3/PR cell-derived exosomes were detected using Western blotting.The CCK8 and Transwell assay were used to investigate the effects of the transfection of SKBR-3/PR cells with miR-18b-5p inhibitor and extraction of exosomes on the proliferation, invasion and migration of SKBR-3 cells.The targeted binding sites of miR-18b-5p to NEDD9 were predicted using Bioinformatics prediction software Target Scan.Dual luciferase assay was used to analyze the targeted regulation relationship between miR-18b-5p and NEDD9.The effects of up-regulation of NEDD9 on the invasion and migration of SKBR-3 cells were detected using Transwell assay.

ResultsThe expression of miR-18b-5p in breast cancer cell line was higher than that in normal cancer cell line(P < 0.01).The expression levels of CD63 and TSG101 specific proteins SKBR-3/PR in cell-derived exosomes were high(P < 0.01).The proliferation, invasion and migration of SKBR-3 cells were significantly inhibited by the extractive exosomes of SKBR-3/PR cells transfected with miR-18b-5p inhibitor(P < 0.01).The prediction results of bioinformatics software Target Scan showed that the NEDD9 3'UTR had potential binding sites with miR-18b-5p, and the miR-18b-5p could negatively regulate NEDD9 gene expression(P < 0.01).The overexpression of NEDD9 could inhibit the invasion of SKBR-3 cells(P < 0.01).

ConclusionsThe miR-18b-5p can promote the invasion and migration of breast cancer cells by targeting NEDD9.