Exosomal transfer of miR-195-5p restrains lung adenocarcinoma progression.

Exosome is an important way for tumor cells to communicate with other cells and plays an important role in tumor progression. Previous studies revealed that miR-195-5p acts as a tumor suppressor in lung cancer. However, the role and molecular mechanism of exosomal transferred miR-195-5p in lung adenocarcinoma (LAC) remains unknown. Here, we found that miR-195-5p expression in circulating exosomes of LAC patients was lower than that of healthy controls. Meanwhile, the expression of exosomal miR-195-5p from normal bronchial epithelial cell line BEAS-2B cells was significantly higher than that of lung cancer cell lines. The exosome labeling assay confirmed that BEAS-2B cells-derived exosomes could be captured by lung cancer cells. Furthermore, exosomal miR-195-5p derived from BEAS-2B cells remarkably inhibited the proliferation, migration, invasion of lung cancer cells, and tumor growth in vivo. In addition, exosomal miR-195-5p from BEAS-2B cells also suppressed the tube-forming ability of vascular endothelial cells. Moreover, we verified that miR-195-5p decreased apelin (APLN) expression to inactivate the Wnt signaling pathway, thereby inhibiting tumor invasiveness and angiogenesis. In conclusion, our research shows that exosomal miR-195-5p from normal bronchial epithelial cells hinders the progression of LAC, suggesting that regulation of exosomal miR-195-5p provides a novel strategy for LAC treatment.