Fig. 3

MiR-7641 was enriched in exosomes from metastatic breast cancer cells and promoted cancer cell proliferation and invasion. a The miRNA profiles of MCF-7 and MDA-MB-231 cells and their respective exosomes were analyzed by microarrays. Overlapping results of up-regulated miRNAs in indicated groups were analyzed and 10 miRNAs were found to be up-regulated in all the comparisons (MCF-7 exosomes vs. MCF-7 cells, MDA-MB-231 cells vs. MCF-7 cells, MDA-MB-231 exosomes vs. MDA-MB-231 cells, and MDA-MB-231 exosomes vs. MCF-7 exosomes). b qRT-PCR based validation of microarray analysis for miR-7641 highly enriched in metastatic cells and exosomes. The levels of miR-7641 in exosomes from MDA-MB-231 and exosomes from MCF-7 were also validated by qRT-PCR analysis using cel-miR-39 as external control. c qRT-PCR analysis of levels of miR-7641 in MCF-7 and MDA-MB-231 cells transfected with miR-7641 mimics and inhibitors, respectively. d CCK-8 assay-based cell proliferation analysis of MCF-7 and MDA-MB-231 cells transfected with miR-7641 mimics and inhibitors, respectively. e, f The wound-healing assay based cell migration analysis of MCF-7 (e) and MDA-MB-231 (f) cells transfected with miR-7641 mimics and inhibitors, respectively. g, h Transwell invasion assay analysis performed in MCF-7 (g) and MDA-MB-231 cells (h) transfected with miR-7641 mimics and inhibitors, respectively. Each experiment was repeated at least three independent times, and results were presented as mean ± SD. 231: MDA-MB-231, exo: exosomes, scale bar: 100 μm, *p < 0.01, **p < 0.01, ***p < 0.001 compared with control