Inhibitory Effect of IL-9 on Growth of Lung Adenocarcinoma Graft Tumor and Its Action Mechanism
Objective To investigate the effect of interleukin-9(IL-9)on the growth of lung adenocarcinoma in mice and its possible mechanism of action.Methods Mouse lung adenocarcinoma CMT167 cells were inoculated subcutaneously in BALB/C mice to construct a subcutaneous transplantation tumor model of mouse lung adenocarcinoma and to observe the effect of IL-9 on the growth of mouse tumors.Flow cytometry(FCM)and Western blot(WB)were used to detect the expression of IL-9 recep-tor(IL-9R)in mouse lung adenocarcinoma CMT167 cells.CMT167 cells were treated with different concentrations of IL-9 in vitro,and changes in cell viability and apoptosis were observed at different time points.Changes in the percentages of myeloid-derived immunosuppressive cells(MDSCs),CD4+T cells,and CD8+T cells in the tumor tissues of mice were analyzed by using FCM.Results Compared with mice in control group,the growth of mouse lung subcutaneous graft tumors was significantly in-hibited,and the weight of graft tumor was reduced after IL-9 treatment(both P<0.01).Compared with the control group,the expression of IL-9R in mouse lung adenocarcinoma CMT167 cells was significantly increased(P<0.01).After treatment with different concentrations of IL-9 in vitro,there were no significant changes in the viability and apoptosis of mouse lung adenocar-cinoma CMT167 cells compared to the control group.The number of MDSCs in mouse tumor tissues was decreased after IL-9 treatment(P<0.05),while proportions of CD4+T cells and CD8+T cells in tumor tissues were increased(P<0.01).Conclu-sion IL-9Reduces the number of MDSCs and increases the proportions of CD4+T cells and CD8+T cells in mouse tumor tis-sues,therefore inhibits the growth of lung adenocarcinoma tumors in mice.