RESUMEN
Objective:To investigate the expression of miRNA-34b (miR-34b) in non-small cell lung cancer (NSCLC) tissues and its effect on proliferation and invasion of human NSCLC A549 cells in vitro.Methods:The specimens of cancer tissues and paracancerous normal epithelial tissues (more than 5 cm from the edge of the tumor) were collected from 40 NSCLC patients in Shanxi Province Cancer Hospital from June 2015 to March 2017. A549 cells were transfected with miR-34b mimics (experimental group) and irrelevant sequences (negative control group), respectively. The expression of miR-34b in tissues and each group of A549 cells was detected by reverse transcription real-time fluorescence quantitative polymerase chain reaction (qRT-PCR). The proliferation activity of A549 cells in the experimental group and the negative control group was detected by methyl thiazolyl tetrazolium (MTT) assay, and the invasion ability of A549 cells in the two groups was detected by Transwell assay.Results:The relative expression of miR-34b in NSCLC tissues was lower than that in paracancerous normal epithelial tissues (0.52±0.06 vs. 1.05±0.17), and the difference was statistically significant ( P < 0.001). The relative expression of miR-34b in A549 cells of the experimental group was higher than that in the negative control group, and the difference was statistically significant ( P < 0.05). MTT assay showed that the cell proliferation ability (absorbance value) of A549 cells in the experimental group was lower than that in the negative control group after cultured for 24 and 48 hours (both P < 0.01). Transwell assay showed that the number of invaded A549 cells in the experimental group was less than that in the negative control group [(49.53±5.03) cells vs. (121.00±12.06) cells, P < 0.01]. Conclusions:The expression of miR-34b is low in NSCLC tissues, and the up-regulation of miR-34b expression can inhibit the proliferation and invasion of NSCLC A549 cells.