Development of a novel cholesterol tag-based system for trans-membrane transport of protein drugs.

ABSTRACT

The main technological difficulties of developing an intracellular (transmembrane) transport system for protein drugs lie in two points i) overcoming the barriers in the cellular membrane, and ii) loading enough protein drugs, and particularly high-dose proteins, into particles. To address these two technological problems, we recently developed a novel cholesterol tag (C-Tag)-based transmembrane transport system. This pilot study found that the C-Tag dramatically improved the cellular uptake of Fab (902-fold, vs. Fab alone) into living cells, indicating that it successfully achieved transmembrane transport. Moreover, C-Tag-mediated membrane transport was verified using micron-scale large unilamellar vesicles (LUVs, approximately 1.5 µm)-based particles. The C-Tagged Fab was able to permeate the liposomal bilayer and it greatly enhanced (a 10.1-fold increase vs. Fab alone) internalization of proteins into the LUV-based particles, indicating that the C-Tag loaded enough proteins into particles for use of high-dose proteins. Accordingly, we established a novel C-Tag-based transport system that has overcome the known technological difficulties of protein transmembrane delivery, and this might be a useful technology for drug development in the future.