Avaliação de um novo protocolo de imunoterapia com células dendríticas no tratamento de tumores experimentais de mama induzido com células 4T1

Abstract

Introduction: Cancer is the second cause of death worldwide, about 9.6 million in 2018. Immunotherapy with dendritic cells for cancer patients aims to activate the immune response to be eliminate neoplastic cells. Our study aimed to evaluate the immune response profile induced by dendritic cells submitted to different maturation protocols in the spleen and tumor microenvironment of mice with experimental breast cancer. Materials and methods: For this study, bone marrow pluripotent cells of female Balb/c mice were differentiated by stimuly with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). Subsequently, these cells were submitted to two different maturation protocols. In the DCs protocol, dendritic cells were stimulated with TNF-α and tumor lysate. In the LPSDCs protocol, dendritic cells were stimulated with TNF-α, lipopolysaccharide and tumor lysate. DCs and LPSDCs cells were used for immunotherapy of female Balb/c mice with experimental breast cancer induced with 4T1 lineage cells (n= 10 animals each group). After the experimental period, splenic and intratumoral cells were collected and evaluated by flow cytometry. Results: In our study we observed that DCs and LPSDCs reduce the tumor growth rate (p<0.0001) when compared to the untreated breast cancer mice. In addition, we observed that the LPSDCs vaccine induces an increase in the percentage of splenic and intratumoral CD3+ CD4+ T helper cells when compared to the WT (p<0.001) and Tumor (p<0.0001) groups. Both vaccines increased the production of IFN-γ in the tumor microenvironment (p <0.0001) when compared to the Tumor group. The treatment with the LPSDCs vaccine induced a significant reduction in the percentage of regulatory T cells and macrophages in the tumor microenvironment when compared to the Tumor group (p <0.0001) and a higher percentage of CD335+ NK cells when compared to Tumor (p=0.0201) and DCs (p=0.0001) groups. Conclusion: This experimental study demonstrates that in vivo immune responses are induced by immunotherapy with dendritic cells, and additional stimulation with lipopolysaccharide induces increased infiltration of immune cells with antitumor activity and reduction of immunosuppressive cells in the tumor microenvironment.