MicroRNA-107 inhibits tumor growth and metastasis by targeting the BDNF-mediated PI3K/AKT pathway in human non-small lung cancer

Abnormal expression of microRNA-107 (miR-107) was found in non-small cell lung cancer (NSCLC). However, little is known about its role and molecular mechanism in NSCLC progression and metastasis. Therefore, the aims of this study were to clarify the potential role of miR-107 and molecular mechanism in NSCLC progression and metastasis. Quantitative real-time polymerase chain reaction assay showed that miR-107 expression levels were significantly decreased in NSCLC tissue and cell lines. Low miR-107 levels in tumor tissue correlated with advanced TNM stage and lymph node metastasis. Function assays showed that overexpression of miR-107 suppressed cell proliferation, migration and invasion in A549 cells in vitro, and inhibited NSCLC tumor growth in vivo. Further mechanism assays suggested the brain-derived neurotrophic factor (BDNF) was identified as a target gene of miR-107 in NSCLC cells. In addition, BDNF expression was upregulated, and inversely correlated with miR-107 in NSCLC tissues. Enforced overexpression of BDNF effectively reversed the tumor suppressive functions of miR-107 on NSCLC proliferation, migration and invasion. miR-107 overexpression or downregulation of BDNF was able to inhibit activation of PI3K/AKT signaling pathway. Taken together, our findings present the first evidence that miR-107 could suppress NSCLC metastasis by targeting BDNF and indirectly regulating PI3K/AKT signaling pathway, which might lead to a potential therapeutic strategy focusing on miR-107 and BDNF for human NSCLC.