Preliminary Mechanism Of The Effect Of Flagellin And Rapamycin On Tumor In Mice Bearing Breast Cancer

Objective:To investigate the effect of flagellin and rapamycin on tumor growth,metastasis in mice bearing breast cancer and mechanism in tumor.Methods:4T1 cells were injected in BALB/c mice to build models,which were divided into four groups,including Control,RAPA,FliC and RAPA+FliC.FliC and RAPA were administered by intraperitoneal injection every other day.The variant of tumor size was recorded and the suppression ratio of tumor was calculated.The inhibition ratio of 4T1 cells proliferation treated with RAPA and FliC was investigated by MTT assay.Cells were gotten from tumor tissues and the percentage of CD4~+CD25~+Treg,CD11b~+Gr-1~+MDSC and CD11b~+F4/80~+TAM were investigated by flow cytometry.CD8~+T cells were detected by immunohistochemistry and the positive rates were calculated by Image Pro Plus6.0.Tumor metastasis situation in lungs and livers were detected by HE staining.Results:In vivo,tumor suppression ratio of RAPA+FliC was the highest in all groups,about 79.60%±5.561,at the same time,RAPA and FliC were both higher than control group.In vitro,the 4T1 cells inhibition ratio of all experimental groups were higher than control group,but RAPA+FliC group was the highest in all groups,about 42.20%.In tumor,the rate of CD4~+CD25~+Treg was increased,CD11b~+Gr-1~+MDSC and CD11b~+F4/80~+TAM was decreased after treated with RAPA,FliC and both of them.And the ratio of Treg of RAPA+FliC was the highest in all groups,about 27.36%,but MDSC and TAM were lowest,about 6.28%and 5.07%respectively.The ratio of MDSC and TAM of RAPA were also lower than FliC and Control,about 6.58%and 4.88%,as the same as RAPA+FliC.And these cells of FliC were the highest in all groups,about 27.03%and20.17%.Compared with control group,CD8~+T cells were increased,especially FliC group.The metastasis degree of RAPA and RAPA+FliC was better than other groups,especially FliC,which was the worst group both in livers and lungs.Conclusion:The effect of antitumor,suppression tumor growth and metastasis were enhanced in mice bearing breast cancer by FliC and RAPA treated together.The results indicated that the anti-tumor effect of FliC and RAPA working together was more to do with tumor microenvironment and immune cells in tumor more than direct inhibition of tumor cells.