Study On Anti-apoptosis Mechanism Of MDSCs Cells During Mouse Tumor Reconstruction

The immunotherapy for malignant tumors has been proved effectively in recent years.The amount and function of various immune cell subpopulations in the immune system are a key factor in limiting immunotherapy.Therefore,interventions in multiple ways to the immune system are new way to cancer immunotherapy.Myeloid-derived suppressor cells(MDSCs)are one of the most important members of the immunosuppressive cells.They are essentially undifferentiated and mature myeloid cells possessing complex biological functions.MDSCs can accumulate rapidly and helps malignant tumor cells escape immune system,and it has a strong relationship with poor prognosis of breast cancer patients.The accumulation mechanism of MDSCs in malignant tumors patients is not yet clear,thus limiting the development of targeted drugs for MDSCs.Building 4T1 breast cancer mouse model to determine the changes of immune cells in the spleen;Isolating MDSCs from the spleens of 4T1 mouse model,and to investigate the molecular mechanism of cell accumulation in MDSCs during mouse tumor reconstruction.4T1 mouse breast cancer model was constructed by injecting 4T1 cells into mouse mammary fat pad.Flow cytometry was used to detect the changes in the proportion of immune cells in the spleen during the tumor reconstitution in mice.The MDSCs were isolated using density gradient centrifugation.RT-PCR and Western blot were used to screen differential genes and proteins between MDSCs and lymphocytes.Flow cytometry results showed that the proportion and absolute number of MDSCs subsets increased significantly,the proportion of lymphocyte subsets decreased significantly,but the absolute cell number increased significantly.During the density gradient isolation,MDSCs were enriched in the high density layer,and lymphocytes were enriched in the low dendsity layer.When seprating the health mouse spleen,B220+ cells were enriched in the high density layer,and CD3+T was enriched in the low density layer.RT-PCR and Western result showed that Cyclin E,STAT3,and Bcl-2 were highly expressed in MDSCs of 4T1 mice spleen,while lymphocytes highly expressed Caspase 3 and Cleaved-PARP.The mouse breast cancer model was successfully constructed using 4T1 mouse breast cancer cells.