Isolated limb perfusion for local gene delivery - Efficient and targeted adenovirus-mediated gene transfer into soft tissue sarcomas

Objective To evaluate the potential of isolated limb perfusion (ILP) for efficient an d tumor-specific adenovirus-mediated gene transfer in sarcoma-bearing rats. Summary Background Data A major concern in adenovirus-mediated gene therapy in cancer is the transf er of genes to organs other than the tumor, especially organs with a rapid cell turnover. Adjustment of the vector delivery route might be an option c reating tumor specificity in therapeutic gene expression. Methods Rat hind limb sarcomas (5-10 mm) were transfected with recombinant adenovir uses. Intratumoral luciferase expression after ILP was compared with system ic administration, regional infusion, or intratumoral injection using a sim ilar dose of adenoviruses carrying the luciferase marker gene. Localization studies using lacZ as a marker gene were performed to evaluate the intratu moral distribution of transfected cells after both ILP and intratumoral inj ection. Results Intratumoral luciferase activity after ILP or intratumoral administration w as significantly higher compared with regional infusion or systemic adminis tration. After ILP, luciferase gene expression was minimal in extratumoral organs, whether outside or inside the isolated circuit. Localization studie s demonstrated that transfection was confined to tumor cells lying along th e needle track after intratumoral injection, whereas after ILP, lacZ expres sion was found in viable tumor cells and in the tumor-associated vasculatur e. Conclusions Using ILP, efficient and tumor-specific gene transfection can be achieved. The ILP technique might be useful for the delivery of recombinant adenoviru ses carrying therapeutic gene constructs to enhance tumor control.