整合素连接激酶基因敲降和黑色素瘤分化相关基因过表达慢病毒载体构建和鉴定

目的：建立整合素相关激酶(ILK)基因敲降和黑色素瘤分化相关基因(mda7)过表达慢病毒包装表达系统。方法：针对人ILK基因序列，设计基因敲降靶点序列(A、B、C)，通过限制性内切酶HpaⅠ和XhoⅠ双酶切、T4 DNA连接酶连接，将ILK插入慢病毒载体pSicoR-eGFP，构建siILK-pSicoR-eGFP重组质粒；根据人mda7基因序列，设计引物扩增mda7全长，并插入慢病毒载体pLVX-Puro，构建mda7-pLVX-Puro重组质粒。经双酶切及测序鉴定正确后通过脂质体将慢病毒四质粒系统共转染人胚肾细胞系293T细胞，进行慢病毒包装并测定病毒滴度、观察感染效率。各组病毒载体转染PC-3细胞后，用定量PCR和蛋白质印迹法检测ILK基因和mda7 mRNA转录水平及蛋白表达水平。通过MTT法和Transwell实验考察ILK和mda7对PC-3细胞增殖和迁移的影响。结果：成功构建ILK基因敲降及mda7过表达的慢病毒载体，四质粒系统共转染293T细胞后可见大量绿色荧光染色阳性细胞。浓缩病毒后293T细胞的感染效率在90%以上，并能高效率感染PC-3前列腺癌细胞。ILK-A-pSicoR-eGFP和ILK-B-pSicoR-eGFP组ILK干扰效果最佳（P<0.05），mda7的表达水平远高于对照组（P<0.05），且持续稳定表达至少1个月。ILK和mda7对PC-3细胞的增殖在96 h内有明显抑制作用，并对其迁移亦有显著抑制（均P<0.05）。结论：成功构建并鉴定人ILK 基因敲降和mda7过表达慢病毒载体，可为探讨ILK和mda7基因在肿瘤细胞中的生物学功能提供良好工具，也为探索安全、高效的肿瘤治疗途径奠定实验基础。

Construction and identification of lentiviral vector containing human ILK-shRNA and mda7 gene

Objective： To construct and identify lentiviral vector containing human ILK-shRNA and mda7 gene.Methods： Based on the human ILK gene sequences, RNAi target sequences were designed and cloned into the lentiviral vector pSicoR-eGFP by restriction endonuclease HpaⅠ and XhoⅠ double digestion and T4 DNA ligase ligation. Based on the human mda7 gene sequences, PCR primers were designed to clone the full-length mda7, and were cloned into the lentiviral vector pLVX-Puro. After the candidate clones were identified by DNA sequencing, the recombinant plasmid and the three packaging plasmids were co-transfected into the human embryonic kidney 293T cells by lipofectamine 2000 to produce the lentiviral particles. Human prostate cancer PC-3 cells were infected with the constructed lentiviral vector. The ILK and mda7 expression levels in PC-3 cells were quantified by qPCR and Western blot, respectively. The effect of ILK and mda7 on proliferation and migration of PC-3 cells were assessed by MTT method and Transwell assay, respectively.Results： ILK-pSicoR-eGFP and mda7-pLVX-Puro lentiviral vectors were successfully constructed. Strong green fluorescence was observed in the 293T cells under the fluorescent microscope after co-transfection of 293T cells with 4 plasmids of lentiviral vector. The transfection efficiency of the collected virus exceeded 90％ in the 293T cells and the PC-3 cells were infected with the lentiviral particles with high efficiency. The A and B lentiviral vector inhibited the expression of ILK at both the mRNA and protein levels in PC-3 cells significantly. The mda7-pLVX-Puro lentiviral vector increased the expression of mda7 in PC-3 cells, and the ability was maintained for one month. Within 96 h, ILK and mad7 significantly inhibited the proliferation and migration of PC-3 cells (Ps<0.05). Conclusion： The lentiviral vectors of ILK knockdown and mda7 over-expression have been successfully constructed and identified. The recombinant lentivirus can efficiently infect human prostate cancer PC-3 cells, in which ILK expression is inhibited and mda7 is over-expressed.