MiR-191-5p inhibits KLF6 to promote epithelial-mesenchymal transition in breast cancer

BACKGROUND: MicroRNAs (miRNAs) exert certain functions in the development of several cancers and can be a potential hallmark for cancer diagnosis and prognosis. MiR-191-5p has been proven to have high expression in breast cancer (BC), while its biological role and potential regulatory mechanisms in BC remain an open issue. OBJECTIVE: Bioinformatics was utilized to assay miR-191-5p level in BC tissues and predict its downstream target gene as well as the enriched signaling pathways of the target gene. METHODS: qRT-PCR was carried out to assay miR-191-5p and KLF6 levels in BC cells as well as miR-191-5p level in blood-derived exosomes from BC patients. Western blot was to examine the expression of proteins linked with cell adhesion, epithelial-mesenchymal transition (EMT), and exosome markers. A dual luciferase reporter assay was utilized to verify the interaction between miR-191-5p and KLF6. Abilities of cell phenotypes of BC cells were detected by CCK8, Transwell, and cell adhesion assay, separately. RESULTS: Upregulated miR-191-5p expression and downregulated KLF6 expression were observed in BC cells. There was a targeting relationship between miR-191-5p and KLF6. MiR-191-5p negatively regulated KLF6 to promote EMT and malignant progression of BC cells. Additionally, we described a dramatically high level of miR-191-5p in the blood exosomes of BC patients. CONCLUSION: MiR-191-5p advances the EMT of BC by targeting KLF6, indicating that miR-191-5p and KLF6 may be new biomarkers for BC.