Exosomes co‐expressing AQP5‐targeting miRNAs and IL‐4 receptor‐binding peptide inhibit the migration of human breast cancer cells

Aquaporin‐5 (AQP5) plays a role in breast cancer cell migration. This study aimed to identify AQP5‐targeting miRNAs and examine their effects on breast cancer cell migration through exosome‐mediated delivery. Bioinformatic analyses identified miR‐1226‐3p, miR‐19a‐3p, and miR‐19b‐3p as putative regulators of AQP5 mRNA. Immunoblotting revealed a decrease of AQP5 protein abundance when each of these miRNAs was transfected into human breast cancer MDA‐MB‐231 cells. Quantitative real‐time PCR demonstrated the reduction of AQP5 mRNA expression by the transfection of miR‐1226‐3p and a luciferase reporter assay revealed the reduction of AQP5 translation after the transfection of miR‐19b‐3p in MDA‐MB‐231 cells. Consistently, the transfection of each miRNA impeded cell migration. Pathway enrichment analyses showed that these three miRNAs regulate target genes, which were predominantly enriched in the gap junction pathway. For the efficient delivery of AQP5‐targeting miRNAs to breast cancer cells, exosomes expressing both miRNAs and a peptide targeting interleukin‐4 receptor, which is highly expressed in breast cancer cells, were bioengineered and their inhibitory effects on AQP5 protein expression and cell migration were demonstrated in MDA‐MB‐231 cells. Taken together, AQP5‐regulating miRNAs are identified, which could be exploited for the inhibition of breast cancer cell migration via the exosome‐mediated delivery.