Overexpression of miR-206 inhibited the viability of lung adenocarcinoma cells in vitro. A549, PC-9 and HCC827 cells were transfected with different concentrations of negative control or miR-206 mimics for 24, 48 or 72 h. Cell viability was determined using the water-soluble tetrazolium-8 assay. Each experiment was performed three times in triplicate. The results are presented as the mean ± standard deviation (*P<0.05, **P<0.01). miR, microRNA; NC, negative control.