中文摘要：

目的 ：探索微RNA-21（micro RNA-21,mi R-21）以及与Bcl-2相互作用的细胞死亡调节子（Bcl-2 interacting mediator of cell death,BIM）蛋白在人肺腺癌细胞发生表皮生长因子受体（epidermal growth factor receptor,EGFR）-酪氨酸激酶抑制剂（tyrosine kinase inhibitors,TKIs）获得性耐药过程中的作用及调控关系。方法 ：将重组质粒pc DNA3.1-BIM和空质粒pc DNA3.1分别瞬时转染至吉非替尼耐药的肺腺癌细胞株PC9R中,采用实时荧光定量PCR法检测各组细胞中mi R-21的表达水平,细胞计数试剂盒-8（cell counting kit-8,CCK-8）法检测PC9R细胞对吉非替尼的敏感性变化。同时,采用慢病毒感染的方法干扰PC9R细胞株中mi R-21的表达,然后采用实时荧光定量PCR法和蛋白质印迹法检测细胞中BIM基因的表达水平,CCK-8法检测PC9R细胞对吉非替尼的敏感性变化。另外,在干扰mi R-21表达的PC9R细胞中转染pc DNA3.1-BIM重组质粒,然后采用CCK-8法检测PC9R细胞对吉非替尼的敏感性变化。结果 ：重组质粒pc DNA3.1-BIM转染后,PC9R细胞中BIM的表达水平明显提高（P〈0.01）,mi R-21的表达水平也相应升高（P〈0.01）。慢病毒干扰mi R-21表达后,PC9R细胞中mi R-21的表达水平明显降低（P〈0.05）,BIM的表达水平也相应降低（P〈0.05）。下调mi R-21水平和上调BIM表达均能提高PC9R细胞对吉非替尼的敏感性（P值均〈0.05）,而在下调mi R-21表达的同时上调BIM表达,更加提高了细胞对吉非替尼的敏感性（P〈0.05）。结论 ：mi R-21和BIM基因在逆转吉非替尼耐药过程中可能起关键作用,并且二者存在相互拮抗的作用。

英文摘要：

Objective： To investigate the effect and interaction of micro RNA-21（miR-21） and Bcl-2 interacting mediator of cell death（BIM） on acquired drug resistance to epidermal growth factor receptor（EGFR）-tyrosine kinase inhibitors（TKIs） in human lung adenocarcinoma cells.Methods： The empty plasmid pc DNA3.1 and recombinant plasmid pc DNA3.1-BIM were transiently transfected into gefitinib-resistant human lung adenocarcinoma PC9R cells, respectively, then the expression of miR-21 was determined by real-time fluorescent quantitative-PCR（RFQ-PCR）, and the proliferation of PC9R cells treated with gefitinib was detected by cell counting kit-8（CCK-8） assay. Meanwhile, the expression of miR-21 in PC9R cells was interfered by lentivirus infection method, then BIM expression and cell proliferation were detected by RFQ-PCR, Western blotting and CCK-8 assay, respectively. In addition, PC9R cells were transfected with recombinant plasmid pc DNA3.1-BIM and infected with lentivirus of miR-21 interference, then the sensitivity of PC9R cells to gefitinib was detected by CCK-8 assay.Results： After transfection with pc DNA3.1-BIM plasmids, the expression levels of BIM and miR-21 in PC9R cells were increased（P 〈 0.01）. After infection of miR-21 expression interference lentivirus, the expression level of miR-21 and BIM in PC9R cells were downregulated（both P 〈 0.05）. Both knockdown of miR-21 and over-expression of BIM could improve the sensitivity of PC9R cells to gefitinib（both P 〈 0.05）. Moreover, miR-21 knockdown combined with BIM over-expression could further improve the sensitivity of PC9R cells to gefitinib as compared with only miR-21 knockdown group（P 〈 0.05）.Conclusion： MiR-21 and BIM may play key roles in the reversal of gefitinib-resistance to EGFR-TKIs, and they have a mutually antagonistic effect.