| Background:Glioma has been endangering the life and health of all human beings for a long time.Many researchers around the world are committed to exploring and studying the pathogenesis and related factors,tumor microenvironment,immune microenvironment,genomics and epigenetics,glioma stem cells,abnormal biological behavior,gene mutation,molecular typing,pathological types,signal transduction regulation mechanism,drug resistance mechanism and treatment options,in order to gradually solve this global problem.When brain glioma,especially malignant glioma,still can not be completely radical treatment.Nevertheless,in recent years,through the unremitting efforts of many researchers,great progress has been made in the diagnosis and treatment of glioma,which is also due to the progress of surgical treatment,radiotherapy,chemotherapy,molecular and nanotechnology.Currently,the standard treatment for gliomas is a combination of surgery,radiation and chemotherapy.However,postoperative chemoradiotherapy is also a key treatment method.However,in practical clinical work,even with active postoperative chemoradiotherapy,the prognosis of patients is not ideal,and the prognosis survival rate is still not satisfactory.In recent years,with the rapid development of polymer nanomaterials and the continuous progress of science and technology,nanotechnology has been applied more and more in the field of medical biology.In the field of tumor therapy,nano drug delivery system has become one of the hot spots of basic research and new drug research.nano-drug delivery system(NDDS)is an organic combination of nanotechnology and diagnosis and treatment as a new tumor treatment method.The main advantages of nano drug delivery system is the targeted delivery of anti-tumor drugs,improving drug distribution in the body,improving drug solubility,prolonging half-life of drugs,improving bioavailability,reducing systemic toxicity and side effects,etc.The ultimate purpose is to improve the anti-tumor effect of the loaded drugs.Many researchers focus on the development of effective postoperative treatment to obtain satisfactory results.In the process of tumor treatment,the nano drug delivery system can not only load commonly used chemotherapy drugs in clinical practice,but also feedback the therapeutic effect and reduce the adverse reactions and side effects of drugs.In addition,it can load tumor targeting preparations through improvement and modification to further actively target tumor sites and play a more accurate and rapid guiding and therapeutic role.It is of great significance to enhance the clinical therapeutic effect and reduce the toxic and side effects in the course of treatment by striking the tumor in specific areas and reducing the damage to normal tissues.At present,nano drug delivery systems for tumor mainly include inorganic nano biomaterials(nano ceramic materials,nano magnetic materials and nano carbon materials,etc.),organic nano biomaterials(organic small molecule nano biomaterials and organic polymer polymer nano biomaterials)and complex nano biomaterials.The clinical application of inorganic nanomaterials is limited due to their potential cytotoxicity.Recently,the nanoparticle delivery system constructed by polydopamine(PDA)is easily modified due to its unique structure,excellent biocompatibility,favorable photothermal effect,and strong adhesion.The controllable surface area and controllable surface properties are widely used in the biomedical field,and highlight the broad application of anti-tumor drug delivery prospects.In this study,the ph-responsive nanodrug delivery system based on PDA was synthesized by using the active groups such as catechol,amino group and carboxyl group and their strong adhesion,and tumor cell membrane penetrating peptide-1(Pep-1)was introduced as a navigator to guide the nanodrug delivery system into tumor cells accurately.Cell membrane penetrating peptide Pep-1,which belongs to amphiphilic membrane penetrating peptide,contains three domains.Rich in hydrophobic tryptophan,hydrophilic lysine,and domains that enhance stable connections.The hydrophobic N terminal,hydrophilic C terminal and charged domain have a high affinity for the hydrophobic domain of the cell membrane.They can penetrate the cell membrane through the transmembrane mechanism of membrane attachment process,that is,identify with the receptor in the cell membrane,and then attach to the surface of the cell membrane through electrostatic binding.Then it enters the cell through two ways:endocytosis mechanism and direct osmosis mechanism.At the same time,it is confirmed that Pep-1 is a peptide ligand that can specifically bind to interleukin-13 receptorα2(IL-13Rα2)with the highest affinity,which is highly expressed in almost all GBM.IL-13Rα2 is rarely expressed in normal brain cells,but highly expressed in GBM.This specificity makes it an ideal target for therapy in GBM.Therefore,this property of Pep-1 can not only improve the anti-tumor targeting efficacy,but also open up new prospects and provide new hope for anti-tumor therapy.During design,Pep-1 is infused with nanoparticles Pep-1@PDA-TMZ NPs(nanoparticles,based on polydopamine(PDA)doped temozolomide(TMZ).NPs is a promising nanodrug delivery system for chemotherapy(CT)and photothermal therapy(PTT)of glioblastoma(GBM),which achieving dual therapy for tumor cells.Methods:First,2 mg/ml dopamine hydrochloride solution(DA)was added to 10 ml Tris-HCI solution(10 mmol/L,p H=8.5),and the reaction was carried out at 26℃for 8 h under500 r/min oscillation.The color of the mixture changed from bright color to bright yellow with the progress of reaction time,and finally showed brown color.Finally,the mixture was centrifuged by ultra-speed centrifuge(12000 rpm,20 min),and washed with ultra-pure water for several times,and the product was collected as PDA nanoparticles.Then,PDA nanoparticles reacted with TMZ to obtain PDA-TMZ NPs,and finally,PDA NPs and PDA-TMZ NPs were obtained by Schiff base reaction and self-assembly method with Pep-1,respectively,Pep-1@PDA NPs and Pep-1@PDA-TMZ NPs.Finally,Dynamic Light scattering(DLS)and scanning electron microscope(SEM)were used to characterize the size,charge and morphology of the above nanoparticles.The assembly of Pep-1 and TMZ was tested by fourier-transform infrared spectroscope(FT-IR)and ultraviolet and visible spectroscopy(UV-Vis).Fetal bovine serum(FBS)and water were used to investigate the biological stability and dispersion of fetal bovine serum.The biocompatibility of the nanoparticle carrier was verified in vitro anti-tumor experiments,and the cellular uptake and toxicity of the nanoparticle were investigated.The killing effect of U87 cells was monitored by CCK-8 method and staining of live and dead cells.In the study of cell activity,the inhibitory effect of nano drug delivery system on tumor cells in combination with chemotherapy of temozolomide and photothermal effect under 808nm laser irradiation was investigated.Finally,808nm laser was used to locally irradiate the tumor site of nude mice with tumor,and temperature changes were recorded and thermal imaging images were collected.The tumor volume changes of nude mice were measured after treatment in different groups to evaluate the antitumor activities of PDA-TMZ NPs and Pep-1@PDA-TMZ NPs.Blood routine and H&E staining were used to evaluate whether the nanoparticles had damage to each organ.Results:The PDA NPs,PDA-TMZ NPs,Pep-1@PDA NPs and Pep-1@PDA-TMZ NPs have regular morphology,spherical morphology,smooth surface,uniform size,particle sizes of about 122,131,136 and 140nm,respectively.The synthesized nanoparticle carrier has good dispersion,stability,solubility and biocompatibility,and no obvious toxic side effects.The calculated load rate of TMZ is about 50%.In vitro studies showed that Pep-1@PDA-TMZ NPs could enter the nucleus of U87,while PDA-TMZ NPs could not enter the nucleus,but only remained around the cell matrix.According to the investigation,the inhibition rate of Pep-1@PDA-TMZ NPs combined with 808 nm(1W/cm~2)laser irradiation on U87 cells was about 94%.The in vivo anti-tumor activity study showed that the inhibition rate of tumor was about 77.13%,which was higher than that of other groups(p<0.05).Finally,routine blood test and H&E staining analysis of the heart,liver,spleen,lung,kidney and other major organs of nude mice after treatment showed that Pep-1@PDA-TMZ NPs could not cause significant damage to important organs while anti-tumor.Conclusions:The Pep-1 was conjugated and modified to PDA-TMZ NPs,which can serve as a new targeted drug nano delivery system and can offer a CT and PTT integration therapy against GBM.Thus,Pep-1@PDA-TMZ NPs could be a feasible approach for efficient GBM therapy,and further provide some evidence and data for clinical transformation so that gradually conquer GBM. |
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