MiRNA-218, a new regulator of HMGB1, suppresses cell migration and invasion in non-small cell lung cancer

MicroRNAs (miRNAs) function as negative regulators of gene expression involved in cancer metastasis. The aim of this study is to investigate the potential roles of miR-218 in non-small cell lung cancer and validate its regulation mechanism. Functional studies showed that miR-218 overexpression inhibited cell migration and invasion, but had no effect on cell viability. Enhanced green fluorescent protein reporter assay, real-time polymerase chain reaction and western blot analysis confirmed that miR-218 suppressed the expression of high mobility group box-1 (HMGB1) by directly targeting its 3'-untranslated region. Accordingly, silencing of HMGB1 accorded with the effects of miR-218 on cell migration and invasion, and overexpression of HMGB1 can restore cell migration and invasion which were reduced by miR-218. In conclusion, these findings demonstrate that miR-218 functions as a tumor suppressor in lung cancer. Furthermore, miR-218 may act as a potential therapeutic biomarker for metastatic lung cancer patients.