Let-7b miRNA-loaded nanostructures inhibited human tongue squamous cell carcinoma metastasis by the MOR-SRC-EGFR axis

miRNA is a type of classic non-coding RNA which is enriched in cancer. Various studies reported that miRNA be involved in the progression and metastasis of TSCC. Exploring pivotal miRNAs and elaborating the mechanisms inducing metastasis are important for improving the prognosis of TSCC patients. Here, Let-7b miRNA was identified as a significant factor contributing to metastasis of TSCC via directly targeting the 3′UTR of MOR mRNA, which leads to abnormally high expression of MOR protein. MOR might bind with SRC and potentially activate p-EGFR through SRC. As a treatment modality, Let-7b miRNA mimics were encapsulated into the endosomal pH-responsive nanoparticles. NPs (Let-7b miRNA mimics) significantly inhibited Cal27 cells in vitro and in vivo metastatic model. Altogether, our data revealed that Let-7b miRNA-MOR-SRC-EGFR axis might be an effective therapeutic target in TSCC metastasis.