MAPK Pathway Activated By IL-22 In SW480 And A549 Cells

IL-22 is a novel cytokine which is produced by activated mouse T cell carcinoma stimulated with IL-9. It's a new member of the IL-10 family based on sequence and structural similarities, has a simility of 22% with the IL10. IL-22 is mainly produced by two kinds of active T cell: Th17 and Th1 cells. IL-22 signals through a receptor complex consisting of IL-22R1 and IL-10R2 which belonging to the classâ…¡cytokine receptor family. IL-22R1 specially binds to IL-22, and IL-10R2 is the sharing chain of the IL-10 receptor complex and the IL-22 receptor complex. After binding of IL-22 and receptor complex, the signal transduces through the Jak-STAT pathway, then actives Jak1 and Tyk2 to phosphorylate the Tyrosine of STAT1, STAT3, STAT5. Besides, IL-22 can stimulate three main MAPK pathways: MEK-ERK, JNK/SAPK and p38 kinase pathway. Signaling transduction was the basis of communication between cells of organisms. As a new type cytokine, IL-22 involves many signal pathways. Although IL-22 has been reported involving many biological activities, including inflammation response, innate immune system activation, cell proliferation and differenation and gene expression, its effect on cancer cells was left unexplored until now. We found IL-22 plays an important role in signal transduction of SW480 and A549 cells, and our work shed light on the relation between IL family and the progression of tumor.Methods1. Western blot assay was utilized to analyze activation or repression state of preteins of the MAPK pathway: ERK1/2,Src(416),JNK,p38 and other signaling preteins:STAT3,AKT in tumor cell treated with IL-22 .2. Immunoprecipitation assay was applied to detect the activation of Gab1 and its binding with SHP2 in the process of that IL-22 activates MAPK pathway. 3. WST-1 assay was used to detect the effect of IL-22 on cell proliferation of SW480 cells.Results1. IL-22 activates the MAPK pathway: ERK1/2,Src(416),JNK,p38 and other signaling preteins:STAT3,AKT in SW480 and A549 cells.2. IL-22 activates the phosphorylation of Gab1 at the concentration of 100ng/ml, while SHP2 was recruited to Gab1 in response to IL-22. IL-22 induces tyrosine phosphorylation of IL-22R1 and SHP2 binds to IL-22R1.These results suggest that Gab1 and SHP2 maybe involve in the signal pathway activated by IL-22.3. IL-22 also induces cell proliferation of SW480 cells and its relative proliferative rate is 15%.