MicroRNA-200a suppresses migration and invasion and enhances the radiosensitivity of NSCLC cells by inhibiting the HGF/c-Met signaling pathway

Hepatocyte growth factor (HGF), an activator of the c-Met signaling pathway, is involved in tumor invasiveness, metastasis and radiotherapy resistance. In the present study, a novel HGF regulatory pathway in lung cancer involving microRNAs (miRNAs/miR) is described. Immunohistochemical staining and western blot analyses demonstrated that HGF was upregulated and associated with miR-200a downregulation in non-small cell lung cancer (NSCLC) samples compared with normal lung tissues. The association between HGF and miR-200a was associated with the degree of tumor malignancy and cell migration and invasion. miR-200a negatively regulated HGF expression by targeting the 3-untranslated region of the HGF mRNA. miR-200a overexpression induced HGF downregulation, decreased NSCLC cell migration and invasion, promoted apoptosis, and decreased cell survival in A549 and H1299 cells in response to ionizing radiation. The present results revealed a previously uncharacterized role of miRNA-200a in regulating tumor malignancy and radiosensitivity by suppressing HGF expression, a key factor in the HGF/c-Met pathway.