目的：研究人非小细胞肺癌（non-small cell lung cancer，NSCLC）A549 细胞中桥接整合因子-1（bridging intergrator-1，BIN1）对程序性死亡受体-配体1（programmed death-ligand 1，PD-L1）表达的影响及其机制。方法：采用qRT-PCR和Western blotting方法检测A549 细胞和正常人胚肺成纤维细胞2BS中BIN1 与PD-L1 基因和蛋白表达情况，通过基因转染技术、利用阳离子脂质体将含有人全长BIN1 基因序列的真核表达质粒CMV-MCS-GFP-SV40-Neomycin-BIN1 转染到A549 细胞中（BIN1+组），构建过表达BIN1 的细胞株，采用RNA干扰技术将干扰骨髓细胞瘤病毒癌基因（cellular-myelocytomatosis viral oncogene ，c-MYC）的c-MYC-siRNA转染到A549 细胞中（c-MYC-siRNA组）以敲低c-MYC基因表达，通过qRT-PCR和Western blotting 方法验证转染效果及过表达BIN1 基因或敲低c-MYC基因对A549 细胞中c-MYC 和PD-L1 表达的影响。结果：与2BS 细胞相比，A549 细胞中BIN1 基因和蛋白均呈低表达状态，而PD-L1 呈高表达状态（均P<0.05）。将携带BIN1 基因的真核表达质粒转染到A549 细胞后，BIN1 基因和蛋白表达水平较对照组显著升高（P<0.05），而PD-L1 表达显著降低（P<0.05）。c-MYC-siRNA 转染到A549 细胞后，细胞内c-MYC表达显著降低（P < 0.01），PD-L1 表达明显下调（P<0.01）。结论：BIN1 过表达可以通过失活c-MYC通路降低PDL1表达，从而抑制A549细胞的免疫逃逸。

Objective: To investigate the effect and mechanism of bridging intergrator-1 (BIN1) on expression of programmed death-ligand 1 (PD-L1) in non-small cell lung cancer (NSCLC) A549 cells. Methods: Quantitative real-time polymerase chain reaction (qRTPCR) and Western blotting were used to detect the mRNA and protein expression of BIN1 and PD-L1 in A549 cells and normal human embryo lung fibroblast 2BS cells, respectively. Eukaryotic expression plasmid CMV-MCS-GFP-SV40-Neomycin-BIN1 containing human full length BIN1 gene sequence was transfected into A549 cells via cationic liposomes by using gene transfection technology (as BIN1+group); c-MYC-siRNA was used to knockdown the expression of c-MYC in A549 cells through RNA interference technique (as c-MYC-siRNA group). The transfection efficiencies were verified by qRT-PCR and Western blotting, the effects of BIN1 over-expression and c-MYC knock-down on the expression of c-MYC and PD-L1 in A549 cells were detected as well. Results: Comparing with 2BS cells, the expression of BIN1 was down-regulated in A549 cells at both mRNA and protein levels, while the expression of PD-L1 was up-regulated (all P<0.05). The expression of BIN1 was increased at both mRNA and protein level in BIN1+ group, while the expression of PD-L1 was decreased significantly after B1N1 transfection (all P<0.05). After transfection of c-MYC-siRNA into A549 cells, the expression of c-MYC and PD-L1 in c-MYC-siRNA group was down-regulated significantly (all P<0.01). Conclusion: Over-expression of BIN1 could reduce the expression of PD-L1 by inactivating the c-MYC pathway, thereby inhibiting the immune escape of A549 cells.

国家自然科学基金资助项目（No. 81201607）；河北杰出青年基金资助项目（No. H2014206320）；河北人才培养项目资助（No. A201401040）