Multifunctional Nano-delivery System Based On Tumor Starvation Treatment And Chemotherapy

Breast cancer has become a worldwide problem that needs to be overcome due to its high incidence and fatality rate.Surgical treatment is the current strategy in the early stage,but chemotherapy is mainly used in the middle and late stages.However,traditional chemotherapy lacks tumor targeting and shows significant toxicity to healthy tissues and organs.In recent years,the starvation strategy by blocking tumor nutrient supply so as to starve the tumor provides a new way for cancer therapy.Based on the idea of starvation therapy combing with chemotherapy,this work constructs a drug-loaded nanoparticle with the properties of actively targeting cancer cells,p H/hyaluronidase（Hyals）dual responsive drug release,glucose consumption,and inducing tumor coagulation,for breast cancer treatment.The main contents are as follows:（1）Synthesis and characterization of core-layer drug-loaded nanoparticlesCalcium carbonate nanoparticles（CaCO₃ NPs）were synthesized by an microemulsion method and tested by DLS,XRD,BET,and TEM.The results show that CaCO₃ NPs had a particle size of 123.3 nm,a vaterite crystal form and a porous structure.Then,DOX and GOX were loaded into CaCO₃ NPs to obtain drug-loaded nanoparticles[（DOX,GOX）@CaCO₃ NPs].At an optimal mass ratio of DOX or GOX to CaCO₃ NPs of 1:1,the drug loading capacity of DOX and GOX was 46.2%and 9.1%,respectively,and the drug activity was not affect.（DOX,GOX）@CaCO₃ NPs could decrease the p H value of medicum containing glucose due to the production of gluconic acid by the delivery of GOX that was p H responsive.The results CaCO₃ NPs showed a hemolysis rate of less than 5%,indicating a good blood compatibility.CaCO₃ NPs were decomposed and released Ca²⁺to initiate blood coagulation under acidic conditions.（DOX,GOX）@CaCO₃ NPs decreased the p H by the delivery of GOX,and such that accelerated the release of Ca²⁺and blood coagulation.（2）Synthesis and characterization of cysteamine（Cys）decorated hyaluronic acid（HA）HA-Cys was synthesized the reaction between the amino group on Cys and the carboxyl group on HA that was firstly activated by EDC and NHS.¹H-NMR analysis showed that HA-Cys was successfully synthesized,and the Cys substitution degree was18.1%.（3）Preparation and characterization of core-shell drug-loaded nanoparticlesThe core-shell drug-loaded nanoparticles[（DOX,GOX）@CaCO₃/c HA NPs]were prepared by coating HA-Cys on（DOX,GOX）@CaCO₃ NPs,followed by cross-linking,the sulfhydryl group of HA-Cys under oxygen gas.At a mass ratio of core layer to shell layer of 7:3,（DOX,GOx）@CaCO₃/c HA NPs showed a particle size of 262.8nm by DLS and a spherical shape by TEM.The hemolysis rate of（DOX,GOX）@CaCO₃/c HA NPs was measured to be less than 5%,indicating a good blood compatibility.The in vitro release of DOX and GOX from（DOX,GOX）@CaCO₃/c HA NPs was p H/Hyals dual responsive,meanwhile Ca²⁺was fast released.due to the decomposion of nanoparticles under the mimicking microenvironment in tumor cells,showing a potential application for starvation therapy by promoting the blood coagulation of tumor vessels.（DOX,GOX）@CaCO₃/c HA NPs could actively target to both MCF-7 and 4T1 breast cancer cells with over-expressed CD44 receptor,such that increased their uptake by these two cancer cell lines.The cytotoxicity experiments showed that GOX could consume the oxygen and glucose needed by cancer cells and cause the starvation of cancer cells,meanwhile the gluconic acid and H₂O₂ generated by the reaction could promote the decomposition of drug-loaded nanoparticles,and accelerate the release of DOX,which synergistically killed the cancer cells with H₂O₂.