腺病毒介导的VEGF启动子-胸苷激酶表达系统对肝癌细胞的选择性杀伤作用

Adenovirus-mediated gene transfer of thymidine kinase controlled by vascular endothelial growth factor promoter confering sensitivity to ganciclovir in hepatocellular carcinoma cells

目的 :构建携带受血管内皮生长因子 (VEGF)启动子调控的单纯疱疹病毒胸苷激酶基因 (HSV- tk)的重组腺病毒载体 ,并探讨该重组腺病毒对体外培养的肝癌细胞的特异性杀伤活性。方法 :采用 Ad Easy System构建携带受 VEGF启动子或巨细胞病毒 (CMV)启动子调控 tk基因表达的 Ad VEGF- tk和 Ad CMV- tk,这两种重组腺病毒载体在 2 93细胞中包装、扩增后 ,体外感染正常肝细胞系 L 0 2和肝癌细胞系 Hep G2 ,并用不同浓度的丙氧鸟苷 (GCV)处理后以 MTT法检测受染细胞的增殖情况。 结果 :Ad VEGF- tk的病毒滴度为 1× 10 1 0 pfu/ ml,Ad CMV- tk为 5× 10 1 0 pfu/ ml。 L 0 2细胞感染 Ad VEGF- tk后对GCV的敏感性无明显改变 ,而 Hep G2细胞感染 Ad VEGF- tk后对 GCV的敏感性明显增加 ,在感染复数 (MOI)为 10 0并用 5 0μg/ m l GCV处理时 ,则有 90 %以上 Hep G2细胞被杀死 ;而 Ad CMV- tk可杀死 95 %Hep G2细胞和 80 %以上 L 0 2细胞。 结论 :VEGF启动子调控的 HSV- tk基因表达可特异性地杀死肝癌细胞 ,同时对正常肝细胞几无影响。

Objective: To investigate the role of herpes simplex virus thymidine kinase (HSV-tk) gene expression driven by vascular endothelial growth factor (VEGF) promoter followed by ganciclovir (GCV) administration in killing hepatocellular carcinoma(HCC) cells in vitro. Methods: Recombinant adenoviral vectors were constructed with HSV-tk under the control of VEGF or cytomegalovirus (CMV) promoter. Then 2 resultant vectors, AdVEGF-tk and AdCMV-tk, were transduced into hepatoma cell line HepG2 and normal liver cell line L02 followed by GCV treatment for 5 d. The sensitivity to GCV of infected cells was measured with MTT method. Results: The AdEasy System produced the recombinant adenovirus of high titers, AdVEGF-tk 1×10 10 pfu/ml and AdCMV-tk 5×10 10 pfu/ml, respectively. Over 90% of HepG2 cells but few of L02 cells infected with AdVEGF-tk became sensitive to 50 μg/ml of GCV at a MOI of 100. On the contrary, 95% of HepG2 cells and 80% L02 cells infected with AdCMV-tk exhibited GCV sensitivity. Conclusion: HCC-specific killing can be achieved by adenoviral vector containing VEGF promoter for the HSV-tk and GCV treatment.