Transgenic IL-2 expression in Ewing tumor cell lines after transfection with Starburst dendrimers and cationic liposomes

Immunotherapy with IL-2 transduced cells requires efficient methods of gene transfer. Nonviral methods were studied intensively in recent years. In this study we examined whether tumor and fibroblast cell lines established from Ewing tumor patients could be efficiently transfected with the IL-2 gene. We chose Starburst dendrimers (Superfect), a novel transfection reagent, for a transfection study and evaluated optimal conditions for gene transfer. Three Ewing tumor cell lines and three fibroblast cell lines obtained from Ewing tumor patients were analyzed. The concentration of IL-2 in the supernatant of transfected cells was measured by ELISA. We found that all three Ewing tumor cell lines transfected by Starburst dendrimers yielded higher IL-2 levels than after lipofection. In contrast to lipofection, expression of IL-2 increased with time and peaked later. In one of three tested fibroblast cell lines transfection using Superfect yielded higher IL-2 levels. IL-2 production was generally lower in fibroblasts as compared to Ewing tumor cell lines. Given the low toxicity of Superfect reagent and the high efficiency of transfection this method seems to be ideal for clinical studies on the immunotherapy of Ewing tumors.