CATIONIC POLYHEXYLCYANOACRYLATE NANOPARTICLES AS CARRIERS FOR ANTISENSE OLIGONUCLEOTIDES

After antisense oligodeoxynucleotides (ODNs) were suggested for therap eutic use in 1978, major advances were made in developing modified oli gonucleotides with increased nuclease resistance and improved cellular uptake, In the present report, positively charged nanoparticles prepa red from diethylaminoethyl (DEAE)-dextran and polyhexylcyanoacrylate ( PHCA) were evaluated as carriers for ODNs, The oligonucleotides were a nalyzed by anion-exchange HPLC, The nanoparticles exhibited a high loa ding capacity, with approximately 35 mu mol ODNs adsorbed per gram of polymeric material, The adsorption efficacy was found to be dependent on the pH, on the ionic strength of the medium, and on the amount of D EAE-dextran. Highest loading for ODNs was achieved at pH 5.5, using a 10 mM phosphate buffer, Oligonucleotides adsorbed to the surface of th e nanoparticles were nearly completely protected against degradation b y the endonuclease DNase I and under in vitro cell culture conditions, whereas unprotected ODNs were totally digested under these conditions , Nanoparticles led to a 20-fold increase in cellular uptake of FITC - oligonucleotides, The internalized oligonucleotides were frequently lo calized as vesicular structures in the cytoplasmatic compartment, Beca use of their temperature-dependent uptake, we propose an active uptake mechanism, such as endocytosis, for the internalization of the ODN-na noparticle formulations.