ANTISENSE EFFECTS OF CHOLESTEROL-OLIGODEOXYNUCLEOTIDE CONJUGATES ASSOCIATED WITH POLY(ALKYLCYANOACRYLATE) NANOPARTICLES

Oligonucleotides covalently attached to a cholesteryl moiety are moro stable in biological media and better taken up by eukaryotic cells. Ho wever, their anchoring in hydrophobic cellular membranes and endosomes after endocytosis restricts their access to cellular nucleic acids. N ew methods of cellular delivery and the biological activity of the con jugates were studied. The cholesteryl residue was conjugated via disul fide bond to the 5' or 3' terminal phosphate group of two oligodeoxyri bonucleotide dodecamers complementary to the mutated region of Ha-ras oncogene mRNA. The conjugates were able to form complementary duplexes with the mutated 27-b target fragment of mRNA but not with the wild-t ype sequence. Efficient sequence-specific RNase H cleavage of compleme ntary mRNA was induced with low (less than or equal to 500 nM) concent rations of the conjugates. At higher concentrations, this cleavage was progressively inhibited, probably due to an interaction between RNase H and the cholesterol residue. The hydrophobic conjugates could be ad sorbed onto poly(isohexylcyanoacrylate) nanoparticles via their choles teryl moieties and delivered to eukaryotic cells. Cholesterol-conjugat ed oligonucleotides were able to sequence-specifically inhibit the pro liferation of T24 human bladder carcinoma cells in culture.