Methotrexate-Loaded Extracellular Vesicles Functionalized with Therapeutic and Targeted Peptides for the Treatment of Glioblastoma Multiforme

Despite promising in vitro evidence for effective glioblastoma treatment, most drugs are hindered from entering the central nervous system because of the presence of the blood-brain barrier (BBB). Thus, successful modification of drug delivery and novel therapeutic strategies are needed to overcome this obstacle. Extracellular vesicles (EVs), cell-derived membrane-encapsulated structures with diameters ranging from 50 to 1000 nm, have been explored as the drug delivery system to deliver their cargo to the brain tissue. Moreover, tumor targeting and selective drug delivery has been facilitated by engineering their parent cells to secrete modified EVs. However, the method suffers from many shortcomings including poor repeatability and complex and time-consuming operations. In this context, we present an easy-to-adapt and highly versatile methodology to modify EVs with an engineered peptide capable of recognition and eradication of glioma. On the basis of molecular recognition between phospholipids on EV lipid bilayer membranes and ApoA-I mimetic peptides, we have developed methotrexate (MTX)-loaded EVs functionalized with therapeutic [Lys-Leu-Ala (KLA)] and targeted [low-density lipoprotein (LDL)] peptides. In vitro experiments demonstrated that EVs decorated with LDL or KLA-LDL could obviously ameliorate their uptake by human primary glioma cell line U87 and permeation into three-dimensional glioma spheroids in contrast to blank EVs, and consequently, the treatment outcome of the payload is improved. Both ex vivo and in vivo imaging experiments revealed that peptide LDL could obviously promote EV extravasation across the BBB and distribution in the glioma site. Furthermore, compared with the mice administrated with MTX and MTX@EVs, MTX@EVs-KLA-LDL-treated mice showed the longest median survival period. In conclusion, functionalizing with the peptide onto EV surfaces may provide a substantial advancement in the application of EVs for selective target binding as well as therapeutic effects for brain tumor treatment.