| Brain Glioma,originated from the neuroglial cell,is the most common primary intracranial tumor.Among which,Glioblastoma Multiforme(GBM)is the most frequent CNS tumor,can easily diffuse to surrounding normal tissue,which set an obstacle in the conventional surgical treatment.Currently,the most accepted chemotherapy method is limited by severe systemic side effects.Furthermore,the presence of the blood-brain barrier(BBB)prevents nearly 98%of small molecules and 100%of large molecules to be uptake,giving another shadow to chemotherapy.Herein we designed a drug delivery system that can deliver therapeutic agent effectively across BBB and locate in the tumor bed of GBM instead of infiltrating cells.Low-density lipoprotein receptor-related protein(LRP)is a receptor of BBB,so IgG,which is an active targeting ligand,is used to modify our carrier so that it can actively cross the BBB by LRP mediated transcytosis.Acacetin,a hydrophobicity and has difficulty in dissolving in water,was selected as model drug.Furthermore,an increasing number of studies demonstrate that acacetin possesses anti-cancer and neuroprotection activities.In this study,we used liposomes as carriers.IgG,anchored on the surface of our liposome to be an active targeting ligand,can make the liposome pass through the BBB and sequential targeting of brain glioma U87 MG cells.This new type of liposomes can be used as the ideal delivery system of anti-GBM drugs as well as other ant-central nervous system disease drugs.The following parts are included in this paper.1.Successfully synthesis of CL-PEG2000-Mal,then conjugating with IgG to finally acquire active targeting ability via LPR mediated endocytosis.2.Establish a HPLC method for acacetin determination in vitro to measure the entrapment efficiency of the method(using the thin film dispersion method,combined with extrusion of crude liposomes).The best prescription is:phospholipids account for 5%of the prescription(W/V),the ratio of total cholesterol and phospholipid is 1:4(W/W),with the ratio of drug and total lipid is 1:20(W/W),Hydration medium is 10%trehalose.The entrapment efficiency of IgG modified acacetin-loaded liposomes is above 80%,the average particle size is 163 nm,polydipersity index is 0.352.IgG modified acacetin-loaded liposomes were generally spherical and vesicle-like shape and owned a good release behavior.3.The MTT assay and the cellular uptake assay proved that IgG modified Rho labeled empty liposome has lower cytotoxicity and enhanced cellular uptake by U87 MG cells or bEnd.3 cells,IgG modified acacetin-loaded liposome exhibited the strongest inhibitory effect to the proliferation of U87 MG cells.Furthermore,cellular uptake assay of U87 MG cells suggests that the uptake efficiency of IgG modified liposome is much higher than plain liposome(1.22-fold,1.91-fold,2.24-fold,2.27-fold and 2.55-fold),the same tendency can be also observed in bEnd.3 cells.4.The transportation across the bEnd.3 monolayer assay and Dual-targeting effects in vitro demonstrated that IgG modified liposome can cross BBB effectively and located in U87 MG cells,what's more,the liposomes cross BBB in intact form.In a word,IgG modified liposome we synthesized here has increased the transportation ability of crossing the BBB and afterwards targeted the U87 MG cells.it is prospective dual-targeting drug delivery system for therapy of brain glioma.The MTT experiment confirmed the IgG globulin modification enhance cytotoxicity of the acacetin,the cellular uptake assay and inhibitory assay showed the active targeting liposomes can enhance the intake of cells,and has a specific targeting-ability.Results of the transportation across the bEnd.3 monolayer assay and dual-targeting assay in vitro confirmed our hypothesis,that is,it can successfully transport across the BBB and target the U87 MG cells.All in all,this new type of liposomes is a prospective dual-targeting drug delivery system for therapy of brain glioma. |
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