Exosomal miR-196a-5p contributes to esophageal squamous cell carcinoma malignant progression by inhibiting ITM2B.

Exosomes from cancer cells function as carriers to spread or transport specific microRNAs (miRNAs) to distant sites to exert their effects, but the mechanism of exosomal miRNA action in esophageal squamous cell carcinoma (ESCC) has not been fully explained. Therefore, in this study, we were interested in the impact of exosomal miR-196a-5p in ESCC progression. We found that miR-196a-5p was expressed enriched in clinical tissues, ESCC cells, and exosomes. Functionally, depletion of miR-196a-5p impeded ESCC cell growth, migration, and invasion, whereas overexpression of miR-196a-5p produced the opposite results. Moreover, enhancement of exosomal miR-196a-5p in recipient ESCC cells triggered more intense proliferation and migration. Mechanistically, we identified integral membrane protein 2B (ITM2B) as a direct target of miR-196a-5p. Silencing of ITM2B partially counteracted the inhibitory effect of miR-196a-5p inhibitors on the malignant phenotype of ESCC. Furthermore, in vivo, lower miR-196a-5p levels triggered by the introduction of antagomiR-196a-5p resulted in the generation of smaller volume and weight xenograft tumors. Thus, our results demonstrated novel mechanisms of exosomal and intracellular miR-196a-5p-mediated ESCC growth and migration and identify the interaction of miR-196a-5p with ITM2B. These works might provide new targets and basis for the development of clinical treatment options for ESCC.