Therapeutic Effect And Mechanism Of Novel Dendritic Cell Vaccine Combined With Anti-TNFR2 Antibody On Colorectal Cancer Mode

Objective:Colorectal cancer(Colorectal cancer,CRC)is the third most common malignancy in the world,and its incidence and mortality rate are increasing year by year.CRC is not clinically effective at present due to the characteristics of easy recurrence after surgery and resistance to radiotherapy.Therefore,new therapeutic strategies for CRC need to be explored.The immunotherapy represented by dendritic cells(Dendritic cells,DCs)vaccine has a certain therapeutic effect on tumors,but the existing DC vaccine has limited therapeutic effect on tumors and cannot achieve a cure.TNFR2 plays an important role in the process of tumor immune escape,and anti-TNFR2 antibody can attenuate TNFR2-mediated immune escape,thus enhancing the DC vaccine-mediated immunotherapeutic effects.In order to develop highly effective combination immunotherapy with a new DC vaccine,this study proposes to use HMGN1 and 3M-052 to synergistically stimulate DC so as to obtain a new vaccine and combine it with anti-TNFR2 antibody to investigate the therapeutic effect of the novel DC vaccine combined with anti-TNFR2 antibody on CRC and provide a new idea for the treatment of CRC patients.Methods:1.Mouse bone marrow-derived DC were obtained and stimulated with HMGN1 and 3M-052 in vitro to promote their maturation for the preparation of DC vaccine,and their functions were detected by flow cytometry and ELISA.2.Balb/c mouse CRC model was established using CT26 colorectal cancer cell line,treated with prepared DC vaccine combined with anti-TNFR2 antibody,and the tumor growth and survival time of tumor-bearing mice were monitored.3.The number of CD8~+IFNγ~+cells and Treg cells in tumor tissues and spleen were detected by flow cytometry.4.Tumor re-challenge experiments were performed on tumor-free mice that had been cleared of CT26 tumors.CT26 cells were inoculated on the ipsilateral side of the back of the mice and 4T1 breast cancer cells on the contralateral side to observe tumor growth.Results:1.A new DC vaccine was successfully constructed,and the combination of HMGN1 and 3M-052 was able to stimulate DC maturation activation and increase its production of pro-inflammatory cytokines IL-12 and TNF-α.2.The new DC vaccine combined with anti-TNFR2 antibody cleared CT26 colorectal cancer and prolonged survival in mice.3.Flow cytometry assays revealed significantly higher numbers of CD8~+IFNγ~+cells(P<0.05)and significantly lower numbers of Treg cells(P<0.05)in the tumor tissues and spleens of the treated group than in the control group.4.Immunoprotection against homozygous tumors was obtained in cured mice.The tumor re-challenge assay revealed that CT26 inoculated on the ipsilateral side of treatment did not form tumors and 4T1 inoculated on the contralateral side grew into tumors.Conclusion:Combined stimulation with HMGN1 and 3M-052 resulted in a new DC vaccine with a high level of mature activation,which,in combination with anti-TNFR2 antibody,was able to induce anti-tumor T-cell responses and suppress immune tolerance,exert tumor clearance and establish immune memory,and protect cured mice from developing homozygous tumors.