Th9 cytokines inhibit proliferation, promote apoptosis, and immune escape in thyroid carcinoma cells

Abstract Objective: To investigate the regulatory effects of T helper 9 (Th9) cytokines on the proliferation, apoptosis and immune escape of thyroid cancer cells. Methods:The survival rate of human thyroid cancer cell line TPC-1 after treatment with 0, 1, 2.5, 5, 10, 20 ng/ml IL-9 (or IL-21) was determined by CCK-8 method and suitable concentrations of IL-9 and IL-21 were screened out. The TPC-1 cells cultured in vitro were randomly grouped into control group, IL-9 group, IL-21 group and IL-9+IL-21 group. After treatment with IL-9 and IL-21 factors, the proliferation and apoptosis of TPC-1 cells in each group were detected by CCK-8 method and flow cytometry respectively. The flow cytometry was applied to detect the proportion of Th9 and activated CD8+ T cells in human peripheral blood lymphocytes co-cultured with TPC-1 in each group. The expression of TPC-1 and IL-9R and IL-21R protein in each group and human peripheral blood lymphocytes. Results: Compared with the control group, the cell viability PCNA and Bcl-2 protein expression in TPC-1 cells were lower in the IL-9 group, IL-21 group and IL-9+IL-21 group (P<0.05). The apoptosis rate, proportions of Th9 and activated CD8+ T cells, killing rate of human peripheral blood lymphocytes, the expression of Bax and caspase-3 proteins in TPC-1 cells, the expression of TPC-1 and human peripheral blood lymphocytes IL-9R and IL-21R proteins were all higher (P<0.05) in IL-9+IL-21 group compared with the IL-9 group and the IL-21 group. The cell viability, PCNA and Bcl-2 protein expression in TPC-1 cells in the IL-9+IL-21 group were all lower (P<0.05). Conclusion:Th9 cytokines can promote the differentiation of Th9 cells and CD8+ T cells, enhance their lethality, reduce the immune escape of thyroid cancer cells, and then inhibit their proliferation and promote their apoptosis.