Preliminary Study Of DC-derived Exosomes In Breast Cancer Immunotherap

Background:The latest statistics of the World Health Organization(WHO)in 2020 show that breast cancer has surpassed lung cancer to become the cancer with the highest incidence in the world.at present,the treatment of breast cancer includes surgical treatment,chemotherapy,radiotherapy,targeted therapy and immunotherapy.Early diagnosis and early treatment of breast cancer can significantly improve the prognosis.The 5-year survival rate of patients with early breast cancer can reach 93%.There are four types of breast cancer: Luminal-A,Luminal-B,HER-2 and triple negative.Triple negative breast cancer(TNBC)has little effect on targeted therapy and endocrine therapy due to the lack of corresponding targets,so it must be treated with chemotherapy after operation.While developing rapidly,it is easy to relapse and metastasis,then the prognosis is not ideal.Therefore,we’ve been trying to find a quite effective immunotherapy to improve the survival rate of breast cancer patients and improve the prognosis.Tumor immunotherapy including monoclonal antibody immune checkpoint inhibitors,therapeutic antibodies,cancer vaccines,cell therapy and small molecule inhibitors is a therapeutic method to control and remove tumors by starting and maintaining the anti-tumor-immune cycle and restoring the normal anti-tumor immune response.It has shown strong anti-tumor activity in the treatment of a variety of solid tumors,such as melanoma,non-small cell lung cancer,renal cell carcinoma and so on.In the IMpassion130 and IMpassion131,the median overall survival time of PD-L1 positive breast cancer patients treated with atezolizumab plus albumin-bound paclitaxel(25.0 months)was significantly longer than that of albumin-bound paclitaxel alone(15.5 months),which opened a new chapter in immunotherapy for breast cancer.Tumor immunotherapy plays a therapeutic role in inhibiting tumor growth and clearing tumor by starting anti-tumor-immune cycle and maintaining the activation of anti-tumor immune response in vivo.Based on the results of the IMpassion130 study,on March 8,2019,FDA accelerated the approval of atezolizumab binding to paclitaxel protein to triple negative breast cancer(TNBC)patients for adult treatment of locally advanced or metastatic,unresectable and that PD-L1 is positive.Atezolizumab became the first immunotherapy approved for breast cancer,thus ushering in the era of immunotherapy for breast cancer.Exosomes are nano-sized vesicles secreted by cells which are closely related to the occurrence and development of tumors,the formation of tumor microenvironment and the regulation of immune response.It participates in all aspects of tumor screening,diagnosis and treatment.At the same time,it also has the advantages of immune prototype and low toxicity.Dendritic cells(DC)are the most powerful full-time antigen presenting cells(APC)now,which can activate primitive T cells and stimulate immune response,thus playing a huge role in the function of immune surveillance.DC-derived exosome(DEX)can not only play the immune function of DC,but also have the biological activity of exosome.These characteristics make DC-derived exosome(DEX)play a unique part in inducing and maintaining anti-tumor immunotherapy.Objective:The exosome of dendritic cells derived from mouse bone marrow are extracted and co-cultured with T cells,which can activate T cells and induce their immune killing effect on tumor cells,and then exosome tests are carried out in animal experiments.If the results of this experiment are established,patients with breast cancer can receive targeted immunotherapy under specific conditions,then improving the efficiency and prognosis of patients with breast cancer.Methods:The experimental design proposal is detailed in the text data and methods.Take the human body as an example,after surgery,tumor cell lysate is made of by the tumor tissue.At the same time,peripheral blood monocytes are extracted by ultra-speed separation,which are induced to differentiate into immature DC.Immature DC and tumor lysate are co-cultured to promote differentiation into mature DC.DC-derived exosome(DEX)is isolated and extracted,then injected into human body for tumor immunotherapy.In the meantime,DEX and ICI can be combined to observe the effect of immunotherapy.Take animals as experimental subjects,firstly,DEX was isolated by the kit and identified.Then the tumor cell lysate was made by the mouse malignant breast cancer cell 4T1 in experimental group,then dealt with the bone marrow-derived DC of mice,and extracted the exosome after differentiation;while in control group,the exosome was directly isolated from DC derived from mouse bone marrow cells and co-cultured with T cells.The tumor-bearing mice were treated with drugs respectively to verify its therapeutic effect.Then combined with immune checkpoint inhibitor to treat tumor-bearing mice,and observe its therapeutic effect.Finally,mouse medullary breast cancer cell line E0771 was selected to make tumor cell lysate,and the above steps were repeated to verify the immunotherapeutic effect on tumor-bearing mice.Results:1.Artificial modification of DEX is effective in the treatment of triple-negative breast cancer in mice.2.After the combination of immune checkpoint inhibitors,DEX combined with immune checkpoint inhibitors had better therapeutic effect.3.DEX combined with immune checkpoint inhibitor group had a certain therapeutic effect on Luminai-B breast cancer after switching to E0771 cells.Conclusion:1.DEX has a great immunotherapeutic effect on triple negative breast cancer.2.The therapeutic effect of DEX combined with immune checkpoint inhibitor was significantly enhanced.