Study On Immunogenic Death Of Breast Cancer Induced By Ferrimagnetic Vortex Magnetic Nanorings

At present,immunotherapy has made some important breakthroughs in the treatment of non-small cell lung cancer,breast cancer and other treatments.In particular,therapeutic oncology vaccines,such as Sipuleucel-T（Provenge?）,were approved by the FDA in 2010 for the treatment of metastatic castration-resistant prostate cancer.Several therapeutic oncology vaccines have been approved,including DCVAX^?-Brain,M-VAXTM,Hybricell,CIMAVAX EGF^?and Oncophage?.However,the efficacy of various immunotherapies,including therapeutic tumor vaccines,remains to be improved,mainly because of the low anti-tumor immune response induced by vaccines.How to induce immunogenic cell death（ICD）of cancer cells is the key to solve the therapeutic effect of immunotherapy.In recent years,magnetothermothermal therapy（MTT）based on the induced thermal effect of magnetic nanoparticles（MNPs）in alternating magnetic field（AMF）has gradually become a new treatment method for malignant tumors.MTT has the characteristics of penetrating deep tissue,high selectivity,strong targeting and specific killing of tumors.Although the immunological effects of MTT have been reported,whether MTT can induce ICD has not been systematically demonstrated.In this paper,a highly effective ferrimagnetic vortex-domain iron oxide nanoring（FVIOs）with high specific absorption rate（SAR）was used as hyperthermia agent to systematically verify whether MTT can induce ICD and to investigate the immune response of homologous mice through vaccination experiments.Specific research results are as follows:1.FVIOs were synthesized as hyperthermia agents.A 70 nm FVIOs was synthesized by hydrothermal method.The material was characterized by XRD,TEM,FT-IR,etc.It was proved that the composition of the material was Fe₃O₄,the hollow ring,the size was uniform and the water solubility was good.2.Verification of cell ICD induced by FVIOs hyperthermia agent.Immunogenic cell death induced by MTT was investigated by applying an AMF at a safe dose of hyperthermia agent using cytotoxicity test.The results showed that the survival rate of both mouse breast cancer cell line 4T1 and human breast cancer cell line MDA-MB-231 cells was less than 40%after being co-incubated with 75μg/m L FVIOs for 10 min.Through 4 groups of experiments,namely the control group,oxaliplatin group,magnetothermothermal group and traditional water bath group（treated at 43℃for 2 h）,12 indicators were selected for cell level DAMPs signaling molecular verification.The results showed that after MTT,all indexes except TLR3 were significantly changed,while only two heat-related indexes（HSP70 and HSP90）were changed in the traditional water bath group,indicating that MTT can effectively induce the ICD of tumor cells.3.In vivo immunohistochemistry and tumor vaccine validation of ICD induced by MTT.Mice breast cancer model was established.Balb/c mice with 4T1 cell line were used to build a mouse model of subcutaneous breast cancer tumor.After the completion of MTT,the tumor was collected for immunohistochemical verification.The results showed that MTT can induce ICD at the tissue level.At the same time,the experimental results showed that the tumor growth rate was significantly reduced in the 4T1 mouse model of breast cancer subcutaneous tumor,while no similar results were found in the MDA-MB-231 mouse model of breast cancer subcutaneous tumor,suggesting that MTT can induce ICD.Similar results have been reached in vaccine trials,the gold standard for immunogenic cell death.