The placenta is a tissue with the ability to proliferate and invade the myometrium, using similar ways to molecular mechanisms that tumor cells use in tumorigenesis process. Many studies have revealed numerous genes are involved in early migration and invasion steps of the metastatic process and shared with placental development. Inthe last years, many studies have indicated that these genes come under strong expression modulations by microRNAs (miRNAs). miRNAs are small non-coding RNAs that regulate post-transcriptionally gene expression binding in 3 'UTR region of gene target. In this context, the cluster of miRNAs-C19MC involves 46 miRNAs that show exclusive expression in placental tissue, as previously demonstrated by different groups. Some gene targets ofmiRNA-C19MC cluster have been characterized in many cancer types since they stimulate cell proliferation by apoptotic inhibition and promote cell migration and invasion. However, it is unclear the role of miRNAs-C19MC cluster members in tumor process. The goal of this study was to identify the biological function of the miRNAs-C19MC cluster in breast cancer development.A set ofC19MC miRNAs cluster wastransfectedintoSKBR3 cell line to its high expression. After transfection, it was performed clonogenic, migration and invasion assays to determine the biological role of miRNAs-C19MC cluster in breast cancer cell line. The results showed a significant decrease in number of colony-forming(p<0.05), a highly significant decrease of migration, and invasive potential (p<0.001). Our results provide clear evidence of functional role of miRNAs-C19MC cluster in breast cancer cell line. Other cell lines must be investigated to confirm the role of the miRNAs-C19MC in the tumorigenesis process.
Financial Support: CNPq, FAEPA, FAPESP.