Exosomal miR-19a derived from melanoma cell promotes the vemurafenib resistance of malignant melanoma through directly targeting LRIG1 to reactivate AKT and MAPK pathway.

ABSTRACT

Exosomes derived from neighboring v-raf murine sarcoma viral oncogene homolog B1 inhibitor (BRAFi)-resistant melanoma cells mediate the formation of resistance in melanoma cells sensitive to BRAFi. The function and molecular mechanisms of exosomal miRNA in BRAFi resistance of melanoma have not been studied. We found that the expression of miR-19a in BRAFi resistant melanoma cells was significantly higher than that in sensitive cells, and miR-19a contributes to the resistance of melanoma cells to BRAFi by targeting immunoglobulin-like domains protein 1 (LRIG1). miR-19a was highly enriched in exosomes secreted from BRAFi resistant melanoma cells, and these exosomal miR-19a promote the spread of BRAFi resistant. The reactivation of Protein kinase B (AKT) and mitogen-activated protein kinase (MAPK) pathways is the main reason for the BRAFi resistant of melanoma cells. We demonstrated that exosomal miR-19a derived from melanoma cell promotes the formation and spread of BRAFi resistant in melanoma through targeting LRIG1 to reactivate AKT and MAPK pathway. Therefore, miR-19a may serve as a potential therapeutic target in melanoma patients with acquired drug resistance.