DELIVERY OF OLIGORIBONUCLEOTIDES TO HUMAN HEPATOMA-CELLS USING CATIONIC LIPID PARTICLES CONJUGATED TO FERRIC PROTOPORPHYRIN-IX (HEME)

The receptor-ligand interaction between hepatocyte heme receptors and heme was evaluated as a basis for developing a targeted cationic lipid delivery reagent for nucleic acids. Heme (ferric protoporphyrin IX) w as conjugated to the aminolipid dioleoyl phosphatidylethanolamine (DOP E) and used to form cationic lipid particles with dioleoyl trimethylam monium propane (DOTAP). These lipids particles (DDH) protect oligoribo nucleotides from degradation in human serum and increase oligoribonucl eotide uptake into 2.2.15 human heptoma cells (to a level of 50-60 ng oligo/10(4) cells) when compared with the same lipid particles (DD) pr epared identically without heme. The DDH heme level that was optimal f or oligoribonucleotide delivery was also optimal for maximum expressio n of plasmid-encoded luciferase. The enhancing effect of heme was evid ent only at net particle negative charge, Fluorescence microscopy show ed that DDH delivered oligoribonucleotides into both the 2.2.15 cell c ytoplasm and nucleus. DDH may thus he a potentially useful delivery ve hicle for oligonucleotide-based therapeutics and transgenes, appropria te for use in such liver diseases as viral hepatitis, hepatoma, and hy percholesterolemia.