Construction And Evaluation Of Pep-1 And CGKRK-modified Dual-targeting Nano-drug Delivery System For Glioma Treatment

Glioma is the most common and fatal primary brain tumor with high incidence rate and short survival time.At present,the clinical treatment includes surgical resection,radiotherapy and chemotherapy.Because of the invasive growth of glioma cells,the boundary between normal brain tissue and glioma tissue is not obvious,so the operation is very difficult and the risk is high.Due to the existence of the blood-brain barrier(BBB)and blood tumor barrier(BTB),the drug delivery to the brain tumor is very limited.Meanwhile,the low selectivity of chemotherapeutic drugs,weak penetration ability and low endocytosis efficiency has become the barriers which become the obstacle to improve the curative effect.In recent years,the nanoparticle drug delivery system has attracted much attention because of its controlled or sustained-release,the ability of passive or active targeting and biocompatibility.Previous study has demonstrated that the nano drug delivery system modified with the glioma cell homeing peptide,which can enhance the targeting of the tumor site,increase the uptake of tumor cells,reduce the toxicity of normal cells,and thus improve the therapeutic effect.Glioma is a type of solid tumor with very abundant blood vessels,decorated with both glioma cell homeing peptide and glioma neovascular endothelial cell homeing peptide to develop multiple targeted nano-drug delivery systems may further improve the anti glioma effect.In this study,using paclitaxel(PTX)as the model drug,because of the specific homing ability between Pep-1 peptide and glioma cells as well as between CGKRK peptide and glioma neovascular endothelial cells,polyethylene glycol-polylactic acid-glycolic acid block copolymers(PEG-PLGA)nanoparticles were decorated with both Pep-1 peptide and CGKRK peptide to develop multiple targeted nano-drug delivery systems.Therefore,drugs loaded into the multiple targeted nano-drug delivery systems could be delivered into glioma cells and glioma neovascular endothelial cells simultaneously.The anti-glioma effects are cooperated by two aspects.One is the destruction of glioma blood vessels,cutting the glioma nutrition supply chain and "starving to death" of glioma cells and tissues.The other aspect is that the drugs are directly imported into glioma cells by the multiple targeted nano-drug delivery systems and kill glioma cells or glioma tissues.Thereby it can improve the therapeutic effect and reduce dosage,reduce side effects of chemotherapy drugs.Firstly,Pep-PEG-PLGA and CGKRK-PEG-PLGA were synthesized and used to prepare the Pep-1 and CGKRK peptide-functionalized nanoparticles Pep&CGKRK-NP(PC-NP)with emulsion/solvent evaporation method.PC-NP-PTX showed vesicle sizes of around 100 nm and narrow size distributions.The encapsulation efficiency of PC-NP-PTX was 81.7±2.7%and the loading capacity was 3.5±0.1%.PC-NP-PTX significantly enhanced cellular uptake in HUVEC and C6 cells and improved the in vitro anti-glioma activity in the respects of proliferation,tumor spheroid growth,tube formation and migration compared with the groups treated with Taxol?? and NP-PTX.In vivo imaging and glioma distribution assays confirmed that PC-NP-PTX could target and accumulate effectively in glioma site.The in vivo anti-glioma efficacy and safety evaluation showed PC-NP-PTX significantly prolonged the survival time in the mice bearing intracranial glioma and displayed negligible acute toxicity.