OPTIMIZATION OF METHODS TO ACHIEVE MESSENGER-RNA-MEDIATED TRANSFECTION OF TUMOR-CELLS IN-VITRO AND IN-VIVO EMPLOYING CATIONIC LIPOSOME VECTORS

Direct in vivo transfection of tumor nodules in situ via liposome-DNA complexes has been employed as a strategy to accomplish antitumor immu nization. To circumvent the potential safety hazards associated with s ystemic localization of delivered DNA, the utility of mRNA transcript- mediated gene delivery was explored. Capped, polyadenylated mRNA trans cripts encoding the firefly luciferase and Escherichia coil lacZ repor ter genes were derived by in vitro transcription. Transfection of the human breast cancer cell line MDA-ME-435 in vitro was accomplished emp loying cationic liposome-mRNA complexes. Evaluation of a panel of cati onic liposome preparations demonstrated significant differences in the capacity of the Various preparations to accomplish mRNA-mediated tran sfection. Quantitative evaluation of in vitro transfection demonstrate d that target cells could be transfected at a high level of efficiency . The mRNA liposome-complexes were evaluated for in vivo transfection of tumor nodules in human xenografts in athymic nude mice. It could be demonstrated the liposome-mRNA complexes were comparable in efficacy to liposome-DNA complexes in accomplishing in situ tumor transfection. Thus, mRNA may be considered as an alternative to plasmid DNA as a ge ne transfer Vector for genetic immunopotentiation applications.