AIM:To investigate the roles of microRNA-134 (miR-134) in the cisplatin resistance of lung ade-nocarcinoma cells.METHODS:miRNA microarray was applied to compare the miRNA expression profile between A549/CDDP and A549 cells.Real-time PCR was used to confirm the expression of miR-134.miR-134 mimics and inhibitors were transfected into A549/CDDP and A549 cells, respectively.MTT assay was used to detect the sensitivity of lung cancer cells to cisplatin.Western blot was applied to test whether miR-134 regulated forkhead box protein M1 ( FOXM1 ) and multi-drug-associated protein 1 ( MRP1 ) expression.RESULTS: Based on the data of miRNA microarray, 13 miRNAs were found to be differentially expressed in A549/CDDP cells compared with A549 cells, among which miR-134 was the most significantly down-regulated one.Compared with control group, A549/CDDP cells transfected with miR-134 mimics showed greatly enhanced sensitivity to cisplatin as indicated by IC50 values (P<0.01).In contrast, suppression of the miR-134 level in the A549 cells resulted in a decreased sensitivity to cisplatin (P<0.01).FOXM1 siRNA down-regulated the pro-tein levels of FOXM1.A549/CDDP cells transfected with si-FOXM1 showed enhanced sensitivity to cisplatin (P<0.01). In addition, the result of Western blot showed that miR-134 repressed MRP1 protein expression.CONCLUSION: miR-134 effectively increases the sensitivity of lung adenocarcinoma cells to cisplatin, and this effect of miR-134 may be partly due to its regulation of FOXM1 and MRP1 expression.%目的：探讨微小RNA-134（miR-134）在人肺腺癌细胞顺铂耐药中的作用及机制。方法：采用miR-NA芯片筛选A549／CDDP和A549细胞差异表达miRNA，应用real-time PCR验证miR-134的表达。将miR-134模拟物和抑制物分别转染A549／CDDP和A549细胞，应用MTT法检测肺癌细胞对顺铂的敏感性。 Western blot技术检测miR-134对叉头框蛋白M1（FOXM1）和多药耐药相关蛋白1（MRP1）表达的影响。结果：miRNA芯片显示，13种miRNAs在A549／CDDP和A549细胞中呈显著表达；其中，miR-134下调最显著。 miR-134模拟物转染组A549／CDDP细胞对顺铂的敏感性较阴性对照组显著提高（P＜0.01），而miR-134抑制物转染组A549细胞对顺铂的敏感性较阴性对照组显著降低（ P＜0.01）。 FOXM1 siRNA能够有效抑制FOXM1蛋白表达，si-FOXM1转染组A549／CD-DP细胞对顺铂的敏感性较阴性对照组显著提高（P＜0.01）。此外，Western blot结果显示miR-134能够抑制MRP1蛋白表达。结论：miR-134能够增加肺腺癌细胞对顺铂的敏感性，其机制可能与调控FOXM1和MRP1表达有关。
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