Preparation And Evaluation Of Pep-1-modified Glioma-targeting Nanoparticulate Drug Delivery System By IL-13R?2-mediated Endocytosis

Glioma is the most frequent central nervous system tumor and poor prognosis,accounting for 50~60%of primary intracranial tumor in the central nervous system.Since glioma differs from the other tumors by its diffuse of the surrounding normal tissue,it is impossible to make the complete removal of tumor by the conventional surgical method and tumor recurrence is very possible.The average survival time of patients with glioma is only 1~2 years.Therefore,chemotherapy is an indispensable auxiliary method for the treatment of glioma.However,the growth characteristics of glioma and the existence of blood tumor barrier(BTB)make the transportation of chemotherapy drugs into the glioma difficult.So the current clinical chemotherapy effect is not ideal.Nowadays,nanoparticulate targeting drug delivery systems have been attracted increasing attentions to overcome the chemotherapy barrier.The main objective of this study was to develop a paclitaxel(PTX)-loaded PEG-PLGA nanoparticle(NP).Furthermore,nanoparticle was modified by conjugating Pep-1 peptide to form a targeting drug delivery system(Pep-NP)through IL-13R?2-mediated endocytosis in the treatment of glioma.The two chapters of this study are as follows:(1)Evaluation of the in vitro and in vivo targeting efficacy of coumarin-6-labeled PEG-PLGA nanoparticles.(2)Pharmacodynamic evaluation of PTX-loaded PEG-PLGA nanoparticles.At first,Pep-1 was conjugated to the PEG-PLGA copolymer by the reaction of maleimide with thiol group(-SH).Pep-1 modified nanoparticles were prepared with emulsion/solvent evaporation method and coumarin-6 was used as fluorescence probe to trace the targeting nanoparticles.Cellular experiments showed that Pep-NP significantly enhanced cellular uptake than that of unmodified NP and the internalization of Pep-NP was concentration-dependent and time-dependent.More importantly,in vitro C6 tumor spheroids assays showed that Pep-NP effectively improved accumulation and penetration into the tumor spheroids.Furthermore,Pep-NP exhibited a desirable brain biodistribution profile with significantly increased delivery in vivo glioma region.Our results indicated that Pep-1-conjugated targeting PEG-PLGA nanoparticle was a potential brain targeting drug delivery system for glioma drug delivery.Secondly,PTX-loaded Pep-1 conjugated PEG-PLGA nanoparticles were prepared using the emulsion/solvent evaporation method for the treatment of glioma.Cell cytotoxicity experiment showed that Pep-NP-PTX exhibited significantly enhanced cytotoxicity than that of unmodified NP-PTX.In vivo NIR imaging experiments was performed to further evaluate the glioma targeting efficacy of Pep-NP.Pep-NP group exhibited much stronger fluorescence intensity in the glioma site at all-time points when compared with that of unmodified NP.More importantly,compared with that of Taxol~?and NP-PTX,Pep-NP-PTX showed desirable brain biodistribution profile and anti-glioma efficacy with significantly enhanced the survival of glioma-bearing mice(the medium survival was 32 days).Systemic safety tests showed no acute toxicity to hematological system,heart,liver,spleen,lung,kidney and brain in mice.Taken together,these results indicated that based on IL-13R?2-mediated endocytosis,Pep-1-modified PEG-PLGA nanoparticles showed potential anti-glioma efficacy for the treatment of glioma.