Molecular strategies for improving cytokine transgene expression in normal and malignant tissues.

The augmentation and optimization of specific targeted transgene expression systems are important strategies for clinical research into gene therapy and DNA vaccination, due to safety considerations. In this study, we introduced 3' untranslated regions and transcriptional control modifications and direct tandem or combinational vector design strategies into a number of specific cytokine cDNA expression plasmids. The experiments were performed in parallel using both in vivo and in vitro transgene expression systems. In vivo studies were carried out using gene gun delivery of test vectors into mouse skin tissues. A combination of specific cell lines and fresh cell explants were used for in vitro and ex vivo transgene expression assay systems. The results from these comparative experiments demonstrated that a number of molecular biology manipulations can be readily adapted to define and significantly enhance the level or/and duration of transgene expression for a group of clinically relevant cytokine genes, with very similar effects for both in vivo and in vitro test systems. This cytokine transgene expression system may offer a favorable means for improving the efficiency of cytokine gene therapy and DNA vaccines in future clinical studies.