Department of Laboratory Medicine, The Second Affiliated Hospital of Nanjing Medical University, Nanjing 210011, PR China.
Oncol Rep. 2013 Apr;29(4):1435-40. doi: 10.3892/or.2013.2248. Epub 2013 Jan 24.
The aim of this study was to investigate the selective killing effect of the herpes simplex virus-thymidine kinase/ganciclovir (TK/GCV) suicide gene system controlled by the survivin promoter on hepatocellular carcinoma (HCC) cells in vitro. Recombinant plasmid vectors driven by the survivin promoter were constructed. HepG2 HCC and LO2 normal human liver cells were transfected with the recombinant plasmids, green fluorescent protein (GFP)/pSURV, TK/pSURV and TAT-TK/pSURV. GFP expression was detected by fluoroscopy and flow cytometry (FCM). TK gene expression was detected using RT-PCR and western blot analysis. The selective killing effects after GCV application were evaluated by tetrazolium assay, FCM and western blot analysis. Statistical analysis was performed by ANOVA. After transfection with GFP/pSURV, TK/pSURV and TAT-TK/pSURV for 48 h, GFP expression was observed in the HepG2 cells, but not in the L02 cells and TK gene expression was evidently detected by RT-PCR and western blot analysis in the HepG2 cells. Three stably transfected cell lines (HepG2/pSURV, HepG2/TK/pSURV and HepG2/TAT-TK/pSURV) were successfully established. Compared with the HepG2/TK/pSURV group, a significant 'bystander effect' was observed in the HepG2/TAT-TK/pSURV group with the incorporation of unmodifed HepG2 cells at different ratios. Following transfection with TK/pSURV and TAT-TK/pSURV, the growth of HepG2 cells in the presence of GCV was markedly inhibited. This finding was further corroborated by FCM and immunoblot analysis revealed the repressed expression of proliferating cell nuclear antigen (PCNA). Our results showed that the plasmid vectors carrying the TK and TAT-TK fusion protein gene driven by the survivin promoter were successfully constructed and their specific expression in HepG2 cells provided the basis for the targeted gene therapy of HCC.
本研究旨在探讨单纯疱疹病毒胸苷激酶/更昔洛韦(TK/GCV)自杀基因系统受survivin 启动子调控对肝癌(HCC)细胞的体外选择性杀伤作用。构建受 survivin 启动子驱动的重组质粒载体。将重组质粒 GFP/pSURV、TK/pSURV 和 TAT-TK/pSURV 转染 HepG2 HCC 和 LO2 正常肝细胞,荧光显微镜和流式细胞术(FCM)检测 GFP 表达,RT-PCR 和 Western blot 分析检测 TK 基因表达,四唑盐比色法、FCM 和 Western blot 分析评估 GCV 应用后的选择性杀伤作用,采用方差分析进行统计学分析。转染 GFP/pSURV、TK/pSURV 和 TAT-TK/pSURV 48 h 后,在 HepG2 细胞中观察到 GFP 表达,但在 LO2 细胞中未观察到,RT-PCR 和 Western blot 分析在 HepG2 细胞中明显检测到 TK 基因表达。成功建立了 3 株稳定转染细胞系(HepG2/pSURV、HepG2/TK/pSURV 和 HepG2/TAT-TK/pSURV)。与 HepG2/TK/pSURV 组相比,在加入不同比例未修饰的 HepG2 细胞的 HepG2/TAT-TK/pSURV 组中观察到明显的“旁观者效应”。转染 TK/pSURV 和 TAT-TK/pSURV 后,GCV 存在时 HepG2 细胞的生长明显受到抑制。FCM 和免疫印迹分析进一步证实了增殖细胞核抗原(PCNA)表达受到抑制。我们的结果表明,成功构建了携带 survivin 启动子驱动的 TK 和 TAT-TK 融合蛋白基因的质粒载体,它们在 HepG2 细胞中的特异性表达为 HCC 的靶向基因治疗提供了基础。