ELECTROPORATION ENHANCES C-MYC ANTISENSE OLIGODEOXYNUCLEOTIDE EFFICACY

Obtaining high transfection efficiencies and achieving appropriate int racellular concentrations and localization are two of the most importa nt barriers to the implementation of gene targeted therapy. The effici ency of endogenous uptake of oligodeoxynucleotides (ODNs) varies from cell type to cell type and may be a limiting factor of antisense effic acy. The use of electroporation to obtain high intracellular concentra tions of a synthetic ODN in essentially 100% of viable cells is descri bed. It is also shown that the transfected ODNs initially localize to the nucleus and remain there for at least 48 hours. The cellular traff icking of electroporated ODNs is shown to be an energy dependent proce ss. Targeting of the c-myc proto-oncogene of U937 cells by electropora tion of phosphorothloate-modified ODNs results in rapid and specific s uppression of this gene at ODN concentrations much lower than would ot herwise be required. This technique appears to be applicable to a vari ety of cell types and may represent a powerful new investigative tool as well as a promising approach to the ex vivo treatment of hematologi c disorders.