OBJECTIVEAdenovirus vector-mediated herpes simplex virus thymidine kinase gene (ADV-TK) transfer in combination with ganiciclovir (GCV) is one of the major gene therapy strategies to eradicate tumor cells. This study was aimed at determining the in vivo anti-tumor efficacy of ADV-TK in combination with ganiciclovir (GCV).

METHODSA murine xenotransplant model of human small-cell lung cancer was established. ADV-TK was administrated by intra-tumoral injection followed by intraperitoneal administration of GCV. The anti-tumor efficacy was evaluated using index of tumor volume, relative tumor volume, tumor weight, relative tumor proliferative rate, and tumor growth curve.

RESULTSIn the presence of GCV, ADV-TK effectively inhibited growth of human small-cell lung cancer in a dose-dependent fashion. An inhibition plateau was not observed within the current dosage range. ADV-TK at a dose of 6.0 x 10(9) viral particles/kg in the presence of GCV lead to 64.6% and 81.7% inhibition of tumor growth respectively in two independent experiments. ADV-TK or GCV alone caused slight inhibition of tumor growth, which was not statistically significant as compared to the negative control group (P > 0.05).

CONCLUSIONADV-TK followed by GCV is highly efficacious to inhibit the growth of human small-cell lung cancer in a murine xenotransplant model. The results presented here are encouraging to warrant a further clinical evaluation of the potential therapeutic benefits of this strategy.