Screening for the key miRNAs of exosomes that promote tumor progression and metastasis

Intercellular communication is crucial for breast cancer progression and metastasis. Yet, the role of cancer-derived exosomes and their specific miRNAs cargo in mediating intercellular communications needed to be further elucidated. MiRNAs control gene expression post-transcriptionally and are selectively packaged into cancer-derived exosomes. Therefore, we hypothesized that miRNAs in cancer-derived exosomes were most likely the essential components of intercellular communication. To identify the key miRNAs, we chose metastatic MDA-MB-231 and non-metastatic MCF-7 for comparison. The miRNAs profiling of exosomes derived from these two kinds of cells as well as the endogenous miRNAs profiling of the cells were conducted by microarrays. MCF7 cells, MDA-MB-231 cells, exosomes isolated from the conditioned medium of MCF7 cells, and exosomes isolated from the conditioned medium of MDA-MB-231 cells were subjected to microarray analysis.