Objective:To explore the effect of microRNA-194 (miR-194) on cisplatin resistance of non-small cell lung cancer (NSCLC) A549/DDP cell lines and its related mechanisms. Methods:The real-time fluorescent quantitative PCR (qRT-PCR) was performed to detect miR-194 expression differences between NSCLC A549/DDP cells and A549 cells. MiR-194 expression differences were detected after MiR-194-inhibitor transfected into A549/DDP cells. MMT assay,colony formation and flow-cytometric analysis were sequentially performed to detect transfected A549/DDP cells to DDP drug sensitivity,cell proliferation ability,and apoptosis on treatment with DDP. The protein expressions of Bax and Bcl-2 in transfected A549/DDP cells were detected by Western blot. Results:The level of miR-194 in A549/DDP cells was significantly higher than that in A549 cells (P < 0.05). The miR-194 level in A549/DDP cells was significantly lower than that in A549/DDP cells after transfected with miR-194 inhibitor (P < 0.05). The inhibited expression of miR-194 could produce following effects: compared to the control group,the half inhibition concentration (IC50) of DDP in A549/DDP with miR-194-inhibitor cells was decreased (P < 0.05),proliferation ability of A549/DDP with miR-194-inhibitor cells was diminished (P < 0.05),apoptosis after treatment with DDP was increased (P < 0.05). Western blotting results showed that,the expression of Bcl-2 was down-regulated and the expression of Bax was up-regulated in A549/DDP/miR-194-inhibitor cells than those in the control group. Conclusion:miR-194 increases the resistance of A549/DDP cells to DDP through inhibition of apoptosis,up-regulating Bcl-2 protein expression and down-regulating Bax. The inhibition of miR-194 expression can reverse the resistance of A549/DDP cells to DDP.