| Objective:A mouse model of triple-negative breast cancer was constructed and treated with PD-1 inhibitor combined with bevacizumab and albumin paclitaxel to observe its effect on tumor growth.By analyzing the changes of immune cell populations infiltrated in the spleen of mice with triple-negative breast cancer and the cytokines in tumor tissues and their effector functions,it is explored whether the combination of the three can further enhance the anti-tumor immune response and improve the anti-tumor effect.Methods:Twenty-four BALB/c mice were selected and injected subcutaneously with4T1 cells to establish a triple-negative breast cancer mouse model.One week after the mice were subcutaneously inoculated with tumor cells,they were randomly divided into 4 groups(n=6 in each group),and medication was started.They are:control group:(NS 0.2ml/kg/d);albumin paclitaxel group(PAB):(PAB 10mg/kg/d);PD-1 inhibitor+albumin paclitaxel group(anti-PD-1+PAB):(anti-PD-1 2mg/kg/d+PAB 10mg/kg/d);PD-1 inhibitor+albumin paclitaxel+bevacizumab group(anti-PD-1+PAB+BEV):(Anti-PD-1 2mg/kg/d+PAB 10mg/kg/d+BEV 5mg/kg/d),treatment for 20 days.During the medication,the tumor volume of the mice was measured every 4 days,the tumor changes in the four groups were observed,and the tumor growth curve was drawn.After the last treatment,the mice were sacrificed,and the mouse spleens were taken out to prepare a single cell suspension,and the proportions of CD4~+T lymphocytes,CD8~+T lymphocytes,and regulatory T cells(Treg cells)were detected by flow cytometry.Using real-time fluorescent quantitative PCR(q RT-PCR)to detect the expression and secretion of cytokines IL-6,IL-10,TGF-βand IFN-γin tumor tissues.To investigate the effect and mechanism of combination therapy on the growth,proliferation and immune microenvironment of triple negative breast cancer.Result:1.The tumor volume inhibition rates of the PAB group,anti-PD-1+PAB group,and anti-PD-1+PAB+BEV group were respectively 20%,57%,and 89%.Compared with the control group,the tumor growth of the anti-PD-1+PAB group and the anti-PD-1+PAB+BEV group was significantly inhibited(P<0.05),while the PAB group(P=0.088)tumors shrank but did not have statistical difference.The tumor volume inhibition rate of anti-PD-1+PAB+BEV group was significantly higher than that of PAB group and anti-PD-1+PAB group(P<0.05).2.The results of flow cytometry showed that:Compared with the control group,the ratio of CD4+and CD8+T lymphocytes in the PAB group increased(P<0.05),the ratio of Treg cells decreased,and the ratio of CD4/CD8 increased slightly(P>0.05).Compared with the control group,the number of CD4~+and CD8~+T lymphocytes in the anti-PD-1+PAB group,anti-PD-1+PAB+BEV group increased,the ratio of CD4/CD8increased,and the expression of Treg cells decreased.The difference was statistically significant.(P<0.05).3.Real-time fluorescent quantitative PCR results show that:compared with the control group,the expression of negative regulatory factors such as IL-10,IL-6 and TGF-βin the PAB group,anti-PD-1+PAB group,the anti-PD-1+PAB+BEV group were significantly down regulated(P<0.05).Compared with the other three groups,the expression level of the immune-promoting factor IFN-γin the anti-PD-1+PAB+BEV group was significant increased(P<0.05),PAB group IFN-γincreased,but there was no significant difference from the control group(P>0.05).Conclusion:1.PD-1 inhibitor combined with bevacizumab and chemotherapy can significantly restrain the growth and proliferation of triple negative breast cancer.2.The mechanism of inhibiting tumor cell growth may be combined with drugs to increase the number of CD4~+T,CD8~+T lymphocytes and decrease the number of Treg cells.By up-regulating the expression of IFN-γ,down-regulating the expression of IL-6,IL-10,and TGF-βrelated. |
