Exosomal miR-20b-5p Induces EMT and Enhances Progression in Non-Small Cell Lung Cancer Via TGFBR2 Downregulation.

The mechanism by which specific miRNAs in NSCLC exosomes regulate NSCLC progression remains unclear. First, exosomes were isolated and identified. Exosomes were labeled with PKH26 for cell tracking studies. Subsequently, BEAS-2B cells and BEAS-2B cell exosomes were transfected with miR-20b-5p mimics or miR-20b-5p inhibitors, and cell proliferation was measured by EdU and CCK-8. cell migration and invasion were detected by wound healing tests and Transwell. The potential target of miR-20b-5p was predicted and verified by luciferase assay. Relative expression levels of miR-20b-5p and TGFBR2 were detected by qRT-PCR. Protein expression level was detected by Western blot. In addition, A549 cell exosomes were injected into mice through the tail vein and the pathological changes of lung tissue were detected by HE staining. Expression levels of E-cadherin and Vimentin in lung tissues were detected by immunohistochemistry. Our results also showed that high levels of miR-20b-5p in exosomes generated from NSCLC cells conceivably enter the cytoplasm of their own cells and by downregulating TGFBR2, accelerate NSCLC invasion, migration and EMT while promoting NSCLC cell proliferation. Exosome analysis using clinical plasma specimens revealed that miR-20b-5p expression was considerably improved in exosomes from NSCLC patients compared with those from healthy controls. In vitro and in vivo, exosomes with high levels of miR-20b-5p were linked to the progression of NSCLC. Our data suggest that exosomes with high levels of miR-20b-5p can increase development and metastasis of NSCLC cells by downregulating TGFBR2, which would serve as a predictive and diagnostic marker for NSCLC.