Experimental Study On The Efficacy Of HSV1-tk/GCV System On Human Tongue Cancer Cell Line

In an attempt to develop gene therapy for tongue cancer, the present study was undertaken to evaluate, in vitro and in vivo, the theraputic efficacy and toxicity of herpes simplex virus thymidine kinase (HSV1-tk) gene and ganciclovir (GCV) treatment, a widely used prodrug / suicide gene therapy, in human tongue cancer cell line Tbp-TL, by using retrovirus expression plasmid-liposome complex transduction. After selected with G418 for 3 weeks, the HSV1-tk gene was detected in the genomic DNA of the Tbp-TL cells by PCR test, with the primers spicificlly designed for HSV1-tk cDNA; and HSV1-tk mRNA was detected by using in situ hybradizition method. In vitro experiments demonstrated dose- and time-dependent cell killing by transduction of the HSV1-tk gene followed by GCV treatment. The IC₅₀ (the concentration required to elicit 50% growth inhibition ) shifted from 1000 μ g/ mL in non-transduced Tbp-TL cells to 1.1 μ g/ mL in Tbp-TL/TK cells transduced with HSV1-tk gene, with the theraputic indexse of 1000. Treatment with GCV at a dose of 10 μ g/ mL for 5 days led to complete cell death in HSV1-tk transduced tumor cells. When mixed with tk positive cells, the non-transduced cells, both the parent Tbp-TL cells, as well as...