Design of Y-shaped targeting material for liposome-based multifunctional glioblastoma-targeted drug delivery
Since the treatment of glioma in clinic has been hindered by the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB), multifunctional glioma-targeted drug delivery systems that can circumvent both barriers have received increasing scrutiny. Despite recent research efforts have been made to develop multifunctional glioma-targeted liposomes by decorating two or more ligands, few successful trials have been achieved due to the limitation of ligand density on the surface of liposomes. In this study, we designed a Y-shaped multifunctional targeting material c(RGDyK)-pHA-PEG-DSPE, in which cyclic RGD (c(RGDyK)) and p-hydroxybenzoic acid (pHA) were linked with a short spacer. Since c(RGDyK) and pHA could respectively circumvent the BBTB and BBB, c(RGDyK)-pHA-PEG-DSPE-incorporated liposomes could achieve multifunctional glioma-targeted drug delivery with maximal density of both functional moieties. c(RGDyK)-pHA-PEG-DSPE-incorporation enhanced cellular uptake of liposomes in bEnd.3, HUVECs and U87 cells, and increased cytotoxicity of doxorubicin (DOX) loaded liposomes on glioblastoma cells. c(RGDyK)-pHA-PEG-DSPE-incorporated liposomes (c(RGDyK)-pHA-LS) could deeply penetrate the 3D glioma spheroids after crossing the BBB and BBTB models in vitro. Moreover, in vivo fluorescence imaging showed the highest tumor distribution of c(RGDyK)-pHA-LS than did plain liposomes (no ligand modification) and liposomes modified with a single ligand (either c(RGDyK) or pHA). When loaded with DOX, c(RGDyK)-pHA-LS displayed the best anti-glioma effect with a median survival time (36.5 days) significantly longer than that of DOX loaded plain liposomes (26.5 days) and liposomes modified with a single ligand (28.5 days for RGD and 30 days for pHA). These results indicated that design of Y-shaped targeting material was promising to maximize the multifunctional targeting effects of liposomes on the therapy of glioma.