The targeted intracellular delivery of cytochrome C protein to tumors using lipid-apolipoprotein nanoparticles.

Intracellular-acting therapeutic proteins offer a promising clinical alternative to extracellular-acting agents, but are limited in efficacy by their low permeability into the cell cytoplasm. We have developed a nanoparticle (NP) composed of lipid (DOTAP/DOPE) and apolipoprotein (APOA-I) to mediate the targeted delivery of intracellular-acting protein drugs to non-small cell lung tumors. NPs were produced with either GFP, a fluorescent model protein, or cytochrome C (cytC), an inducer of apoptosis in cancer cells. GFP and cytC were separately conjugated with a membrane permeable sequence (MPS) peptide and were admixed with DOPE/DOTAP nanoparticle formulations to enable successful protein loading. Protein-loaded NPs were modified with DSPE-PEG-Anisamide to enable specific NP targeting to the tumor site in a xenograft model. The resulting particle was 20-30 nm in size and exhibited a 64-75% loading efficiency. H460 cells treated with the PEGylated MPS-cytC-NPs exhibited massive apoptosis. When MPS-GFP-NPs or MPS-cytC-NPs were intravenously administered in H460 tumor bearing mice, a specific tumor targeting effect with low NP accumulation in the liver was observed. In addition, MPS-cytC-NP treatment provoked a tumor growth retardation effect in H460 xenograft mice. We conclude that our NP enables targeted, efficacious therapeutic protein delivery for the treatment of lung cancer.