miRNA-200c对非小细胞肺癌A549细胞甲氨蝶呤耐药性的影响

目的 探讨miRNA-200c（miR-200c）在非小细胞肺癌A549细胞耐甲氨蝶呤（MTX）（A549/MTX）中的影响及可能的作用机制。方法 通过实时荧光定量（qRT-PCR）法检测人肺癌亲本细胞株A549细胞、转染miR-200c模拟物（mimic）的A549/MTX细胞（A549/MTX-M）及转染miR- 阴性对照（NC）A549/MTX细胞（A549/MTX-N）中miR-200c的表达水平。分别采用MTT法、锥虫兰染色及流式细胞术检测三组细胞对MTX的药物敏感度、细胞增殖能力及细胞凋亡变化，并采用qRT-PCR检测其P53和P21基因表达的变化。结果 miR-200c在A549细胞中的表达水平显著高于A549/MTX-N细胞；A549/MTX-M细胞miR-200c水平高于A549/MTX-N细胞；用不同浓度MTX刺激细胞，与A549/MTX-N细胞比较，A549/MTX-M细胞的增殖能力减弱、凋亡细胞增多，并呈剂量依赖性，差异均有统计学意义。转染miR-200c mimic后，P53和P21基因表达水平上升，与转染miR-NC细胞比较，差异有统计学意义。结论 miR-200c能够逆转A549/MTX细胞对MTX的耐药性，其作用机制可能是通过P53/P21信号转导通路诱导细胞凋亡来实现的。

Impact of miRNA-200c on Methotrexate Resistance of Non-small Cell Lung Cancer Cells A549

Objective To explore the effect of microRNA-200c (miR-200c) on methotrexate (MTX) resistance of non-small cell lung cancer cells A549 (A549/MTX) and elucidate its related mechanism. Methods Quantitative real-time PCR (qRT-PCR) was used to detect the miR-200c expression in A549 cells, A549/MTX cells transfected with miR-200c mimic (A549/MTX-M) and A549/MTX cells transfected with miR-negative control (A549/MTX-N). MTT assay, Trypan blue staining and flow cytometry analysis were sequentially performed to detect the sensitivity of A549, A549/MTX-M and A549/MTX-N cells to MTX, cell proliferation and apoptosis. qRT-PCR was used to detect the gene expressions of P53 and P21 in these cells. Results The miR-200c expression in A549 cells was significantly higher than that in A549/MTX-N cells. The miR-200c expression in A549/MTX-M cells was significantly higher than that in A549/MTX-N cells. Compared with A549/MTX-N cells, the proliferation inhibition and apoptosis of A549/MTX-M cells were increased after treated with MTX in a concentration-dependent manner, with significant difference. Furthermore, the up-regulated P53 and P21 expression were observed in A549/MTX-M cells, with significant difference compared with A549/MTX-N cells(P=0.023, P=0.015). Conclusion miR-200c could reduce the resistance of A549/MTX cells to MTX with the possible mechanism of inducing the apoptosis through the P53/P21 pathway.