Failure of active targeting by a cholesterol-anchored ligand and improvement by altering the lipid composition to prevent ligand desorption

Publication date: 30 January 2018 Source:International Journal of Pharmaceutics, Volume 536, Issue 1 Author(s): Shoshiro Yamamoto, Yu Sakurai, Hideyoshi Harashima Although anti-angiogenic therapy is predicted to be an effective therapy for treating cancer, selectively targeting tumor endothelial cells (TECs), and not normal endothelial cells, remains a major obstacle. Modifying a drug carrier with a targeting ligand is a popular strategy for developing an active-targeting type drug delivery system (DDS). We previously reported that a cyclo(Arg-Gly-Asp-D-Phe-Lys) (cRGD)-equipped liposome that contains encapsulated siRNA (RGD-MEND) achieved an efficient therapeutic outcome in a murine cancer model. To develop a more efficient TEC-targeting DDS, we examined the effect of the length of the polyethylene glycol (PEG) that is used as a peptide-linker on the cholesterol-scaffold, and liposomal composition on the efficiency of delivery of siRNA to cRGD receptor αVβ3 integrin positive cells. An RGD-MEND modified with shorter linker/no-linker, PEG350 or no-PEG, showed a higher cellular uptake in vitro. However, a shorter or no-linker RGD-cholesterol-modified MEND showed no silencing effect despite its high, in vitro silencing efficiency. To examine the possibility that the cholesterol-scaffold ligand was removed from the surface of the RGD-MEND by interactions with serum proteins, the RGD-MEND was incubated in the presence of a 50% serum solution. The cellular uptake of the chole...
Source: International Journal of Pharmaceutics - Category: Drugs & Pharmacology Source Type: research