| BackgroundChemotherapy is one of the important therapeutic methods for advanced nasopharyngeal carcinoma,but the targeting of systemic drug delivery is weak,and the efficacy of single drug application is poor.Therefore,a new type of targeted multi-drug nanomaterials is urgently needed.Graphene quantum dots(GQDS or GQDs)are low-toxicity nanomaterials that have been widely used in the construction of drug delivery systems.GE11 is a small molecule polypeptide obtained through phage library technology that targets EGFR-positive tumor cells.Therefore,in order to further improve the efficacy of chemotherapy for advanced nasopharyngeal carcinoma and reduce systemic toxic and side effects,it is necessary to construct a drug delivery system based on GQD-targeted EGFR,and preliminarily explore its function and mechanism.Objective(1)Construct the vector GQD@GE11 targeting EGFR based on GQD,and verify its targeting ability and histocompatibility.(2)Construct a targeted drug delivery system(GQD@GE11/DOX/CDDP)based on GQD@GE11,and investigate its function and possible mechanism of action in vivo and in vitro.(3)To explore the histocompatibility of GQD@GE11 and GQD@GE11/DOX/CDDP in order to lay a foundation for their possible clinical application.Methods(1)GQD@GE11 synthesis and characterizationGQD was synthesized from graphite powder.GQD@GE11 was synthesized by the reaction of GQD with GE11 through amide.GQD@GE11/DOX/CDDP was obtained by loading doxorubicin(DOX)and cisplatin(CDDP).(2)Function of GQD and its complex in vitroCytotoxicity of GQD and GQD@GE11 was determined,and targeting,imaging,drug delivery,and antitumor capabilities of GQD@GE11/DOX/CDDP were evaluated.(3)In vivo antitumor and mechanism studies of GQD@GE11/DOX/CDDPThe tumor bearing model of nude mice was established,the tumor volume and weight were observed,and the tumor tissues were collected for pathological analysis.The targeting ability of GQD@GE11/DOX/CDDP was evaluated using in vivo imaging.(4)Biocompatibility assessment of GQD@GE11 and its compoundsBiocompatibility was evaluated by erythrocyte hemolysis rate,erythrocyte morphology,pathological tissue of major organs and blood coagulation system.Results(1)Synthesis and characterization of GQD@GE11GQD@GE11 was synthesized successfully,and the diameter of it was 6.5±1.5nm according to transmission electron microscopy.Based on the resonance transfer of GQD and DOX energy,the GQD@GE11/DOX/CDDP targeted drug delivery system was successfully constructed.When pH=7.4,the CDDP drug release rate was only 24.57%,and when pH=5.5,the CDDP drug release rate reached 57.7%.(2)In vitro functional study of GQD@GE11GQD@GE11 is characterized by low toxicity and targeting.GQD@GE11/DOX/CDDP enters CNE-2 cells via endocytosis,and finally enters the nucleus after release of DOX drugs,which can significantly inhibit the proliferation of tumor cells and induce the apoptosis of tumor cells.(3)Studies on the antitumor effects and mechanisms of GQD@GE11/DOX/CDDP in vivoPathological studies have shown that GQD@GE11/DOX/CDDP can significantly inhibit tumor growth,which may be related to down-regulating Ki67 expression and inducing cell apoptosis.In vivo imaging showed that GQD@GE11/DOX/CDDP had stronger tumor targeting.(4)Biocompatibility assessment of GQD@GE11 and its compoundsThe safety of GQD@GE11 is concentration-dependent.When the concentration reaches 0.2mg/ml,it has the potential to cause erythrocyte aggregation.There was no obvious injury in the morphology of organs and tissues of GQD@GE11 and all treatment groups,and no significant difference in PT and APTT.ConclusionThe GQD@GE11/DOX/CDDP targeted drug.delivery system based on graphene quantum dots has good histocompatibility and can monitor the intracellular drug release process through the level imaging of individual cancer cells.It has the characteristics of targeting nasopharyngeal carcinoma cells,multi-drug loading and PH-dependent drug release,which can enhance the chemotherapy effect of nasopharyngeal carcinoma and reduce systemic side effects.Its anti-tumor mechanism may be related to inhibiting tumor cell proliferation and inducing cell apoptosis.Therefore,this novel targeted fluorescent drug delivery system provides a new way to study the drug release process and targeted therapy for nasopharyngeal cancer. |
