Suicide gene therapy of hepatocellular carcinoma and delivery procedure and route of therapeutic gene in vivo

<正> Objective: To study the induction of sensitivity toganciclovir (GCV) or acyclovir (ACV) in humanhepatocellular carcinoma (HCC) cell line trans-ferred by an Epstein-Barr virus (EBV)-based repli-con expression vector carrying the herpes simplex vi-rus thymidine kinase (HSV-tk) gene, including kill-ing and "bystander" effect, and also the gene delive-ry procedure and route of gene therapy in vivo forHCC.Methods: Liposome-entrapped plasmid pDR2/tk wastransferred into HCC cells, and then different con-centrations of GCV or ACV were added. The trans-ferred cells were mixed with untransferred HCC cellsin different proportion and 200 μmol/L GCV wasthen added into each well. After 72 hours, all sam-ples were measured by MTT colorimetric assay. AnEBV-based plasmid eukarotic expression vector car-rying IL-2 cDNA was used. Three models of gene di-rect injection in the local liver, injection through theportal vein, and injection through the embolized he-patic artery were established in closed Wister rats.For each model, two subgroups, injected either na-ked plasmid DNA or lipofectin-plasmid complex wereincluded. The expression of the IL-2 gene was regu-larly examined immunohistochemically.Results: GCV or ACV could apparently kill thetransferred HCC cells at a concentration of 0. 2μmol/L. The inhibition rate was changed with dif-ferent drug concentrations. The "bystander" effectwas obviously induced at a transferred to untrans-ferred HCC cells ratio of 1:5. IL-2 gene expressionwas observed in liver cells of all animals on day 3,which reached peak within 3-7 days, and declined af-ter day 7. Injection of naked plasmid DNA throughthe hepatic artery plus embolization obtained a bestexpression.Conclusions: EBV-based vector is suitable for carry-ing suicide gene therapy for hepatocellular carcino-ma. Gene direct delivery in vivo combined with in-terventional surgery can be used to treat hepatocellu-lar carcinoma.