Abstract: Objective To investigate the effects of microRNA-134 (miR-134) on the proliferation and apoptosis of non-small cell lung cancer (NSCLC) and its potential molecular mechanism. Methods Quantitative real-time fluorescent polymerase chain reaction (qRT-PCR) was used to detect the differences of miR-134 expression between 10 cases of lung cancer tissues and normal lung tissues, and between normal human lung epithelial cell line BEAS-2B and lung adenocarcinoma cell line A549. miR-NC and miR-134 mimic were transfected into A549 cells. The effect of miR-134 on proliferation of A549 cells was detected by methyl thiazolyl tetrazolium (MTT) and colony form experiment. Flow cytometry was used to determine the effect of miR-134 on A549 cells apoptosis. The effect of miR-134 on the expression of P53 protein was detected by Western blotting. Results The relative expressions of miR-134 in NSCLC tumor tissues and adjacent tissues were 0.429±0.126 and 0.971±0.183 respectively, and the difference was statistically significant (t=7.742, P<0.001). The relative expressions of miR-134 in BEAS-2B cells and A549 cells were 1.013±0.095 and 0.371±0.068 respectively, and the difference was statistically significant (t=17.377, P<0.001). The absorbance (A) values of A549 cells transfected with miR-mimic were 0.451±0.051 and 0.518±0.074 on the third and forth day respectively, and those of A549 cells transfected with miR-NC were 0.683±0.041 and 0.815±0.065 respectively. The proliferation ability of miR-mimic group was significantly lower than that of miR-NC group (t=12.965, P<0.001; t=9.535, P<0.001). The colony forming rates of A549 cells transfected with miR-NC and miR-134 mimic were 91.2%±8.3% and 38.6%±4.5% respectively, and the colony forming rate of A549 cells in miR-134 mimic group was significantly decreased (t=17.617, P<0.001). The apoptosis rates of miR-134 mimic group and miR-NC group were 93.5%±3.7% and 85.4%±2.0% respectively, and the difference was significant difference (t=6.119, P<0.001). The relative expressions of P53 protein in miR-134 mimic group and miR-NC group were 1.816±0.173 and 0.992±0.096 respectively, and the diffe-rence was statistically significant (t=19.308, P<0.001). Conclusion miR-134 can be an effective target for the treatment of NSCLC by increasing the protein expression of P53, inhibiting the viability and proliferation of tumor cells, and promoting the apoptosis of tumor cells.

Key words: Carcinoma, non-small-cell lung, Cell proliferation, Apoptosis, Tumor suppressor protein P53, MicroRNA-134