Application Of Chemotaxis To Induce Neutrophils As Trojan Horse Delivery Therapeutic Nanoparticles For Tumor-targeted Therapy

PurposeTargeting modification and long circulating nanocarriers can improve the targeting efficiency of the tumor site via blood circulation and tumor EPR effect,but still can not avoid rapid clearance caused by phagocytic phagocytosis in the blood circulation.The aim of this study was to prepare paclitaxel PLGA nanoparticles with immunoadjuvant(CpG-ODN)linked to the phagocytic ability of the body's own neutrophils and the directional migration induced by chemokines.It is phagocytosed by neutrophils in the body and acts as a"Trojan horse"with neutrophils that endocytose nanoparticles.The chemokine CXCL1,which is localized at the tumor site,recruits drug-loaded Trojan horses to migrate to tumor sites,constructing a chain pattern of circulating neutrophil phagocytosis,a chemokine-induced tumor site release.In order to increase the targeting problem in the tumor drug delivery system and realize the dual purposes of cancer chemotherapy and immunotherapy,it provides new ideas for cancer treatment.Method1 Paclitaxel-loaded PLGA nanoparticles were prepared by double emulsion method.Protamine sulfate was connected to EDC and NHS-activated nanoparticles,and CpG-ODN was electrostatically adsorbed to prepare CpG-PTX-PLGA-NPs.2 The animal Airpouch model explores the interaction of nanoparticles and neutrophils and the chemoattractant chemotaxis of neutrophils.3 B16 melanoma cells were injected subcutaneously on the back of C57BL/6 mice to prepare a melanoma tumor model.CXCL1 chemokine was injected into the tumor site,and CpG-PTX-PLGA-NPs were injected into the tail vein.After 4 doses,the mice were sacrificed by spondylolisthesis and the tumor volume and weight were weighed.The tumor was inhibited by the nanoparticles.Preparation of lymph node cells,immunofluorescence antibody labeling,flow cytometry,confocal microscopy and other techniques to detect the expression of various immune cells in lymph nodes.To investigate the mechanism of tumor inhibition by CpG-PTX-PLGA-NPs.4 The melanin tumor model mouse serum composition examination,organ tissue cryosection HE staining,etc.CpG-PTX-PLGA-NPs on the organ damage.ResultThe paclitaxel nanoparticles linked to CpG-ODN were successfully prepared.The diameter of the paclitaxel nanoparticles was about 300 nm.Tail veins were injected into melanoma tumor mice.CXCL1 chemokines were injected into tumor sites.Nanoparticles were phagocytosed by neutrophils in mice to form a"Trojan Horse";a chemokine CXCL1located at the tumor site was used to recruit drug-loaded"Trojan horse"to migrate to the tumor site,targeting drug delivery to tumor sites..The antitumor results of the melanoma tumor model mice showed that compared with the control group,the ability of the CPG-PTX-PLGA-NPs group to inhibit tumor growth was significantly enhanced,and the tumor inhibition rate was over 70%.The results of paraffin section showed that there was a large area of tumor necrosis in the CpG-PTX-PLGA-NPs group,and the apoptosis of the tumor cells was severe.The inguinal lymph node images showed that the CpG-PTX-PLGA-NPs group had a lower invasive rate of melanoma tumors,and the proliferation and metastasis of melanoma tumors improved significantly.The number of CD4~+T cell and CD8~+T cell cells in lymphocytes increased,and the body's immune response became more intense.The organ cryosection HE staining results showed that the CPG-PTX-PLGA-NPs group had slight nephrotoxicity.ConclusionIn the C57 mouse melanoma tumor model,the CpG-PTX-PLGA-NPs treatment grouphad significant effects in preventing melanocyte migration and inhibiting the growth of solid tumors in situ.At the same time,the nanoparticle can activate the immune system to a certain extent and enhance the immune system's ability to resist tumors.