Effect Of Interleukin - 27 On Biological Behavior Of Pancreatic Cancer Cells And Its Mechanism

BackgroundPancreatic cancer is considered to be a kind of malignancy with very poor prognosis due to its occult onset and rapid progression. The biological therapy is the new trend of tumor treatment, and it is also the hot spot of pancreatic cancer diagnosis and treatment. Activating the natural immune defense mechanism of host or developing targeted therapy towards the tumor is the core of the biological therapy. IL-27 is a novel member of IL-12 cytokine family, which has extensive regulatory function towards many kinds of immune cells. Additionally, IL-27 can also directly inhibit several kinds of tumors. However, the studies of the effect of IL-27 on pancreatic cancer is limited, researches of the immune modulatory and anti-tumor function of IL-27 will provide theoretical principle for immune therapy targeted on pancreatic cancer. We will study the direct and indirect effects of IL-27 on pancreatic cancer cells, to provide theoretical and experimental basis for the antitumor function of IL-27 on pancreatic cancer cells.Objective1. Study the effect of IL-27 on proliferation, apoptosis, migration and invasion of pancreatic cancer cells.2. Establish a co-culture system of macrophages and pancreatic cancer cells. Detect whether IL-27 can affect the biological behavior of pancreatic cancer cells through macrophages.Methods1. Real-time PCR and Western blot were used to detect the expression of IL-27 specific receptor WSX-1 in pancreatic cancer cells. After treated with IL-27 directly, the proliferation of pancreatic cancer cells was detected by CCK-8, and the cell cycle and apoptosis were detected by flow cytometry. The migration and invasion of pancreatic cancer were detected by Transwell.2. U937 cells were induced by PMA, and the expression of CD68 was detected by flow cytometry. IL-4 was used to induce M2 macrophages, and real-time PCR was used to detect the expression of M1 and M2 macrophage markers. IL-27 was used to stimulate M2 type macrophages, and real-time PCR was performed to detect the changes of M1 and M2 type of macrophage markers. Establish M2 type macrophages/pancreatic cancer cells co-culture system, after adding IL-27, CCK-8 was used to detect the changes of proliferation of pancreatic cancer cells, flow cytometry was performed to detect cell cycle and apoptosis. Western blot was used to detect the changes of cell cycle and apoptosis related protein. Migration and invasion of pancreatic cancer cells were detected by Transwell assay. Using Western Blot to detect invasion related proteins.Results1. The expression of WSX-1 in pancreatic cancer cells was significantly lower than that of spleen tissues and U937 monocytes. IL-27 has no direct effect on the proliferation, cell cycle, apoptosis, migration and invasion of pancreatic cancer cells.2. The expression of CD68 molecules of U937 cells induced by PMA was significantly increased by flow cytometry test. After induced by IL-4, the M1 marker CD86 and IL-12p40 of macrophages were significantly decreased, and the M2 marker CD206 was significantly elevated, and the expression of WSX-1 was also significantly elevated. After stimulated by IL-27, the expression of CD86 and IL-12p40 of M2 type macrophages were significantly increased and expression of CD206 was significantly decreased. After adding the IL-27 into the co-culture system, the proliferation, migration and invasion ability of pancreatic cancer cells were decreased significantly, and the apoptosis rate induced by gemcitabine increased significantly. Western blot showed that after adding IL-27 into co-culture system, the expression of cell cycle related protein CDK4, Cyclin D1 of pancreatic cancer cells decreased significantly, the apoptosis related protein cleaved caspase-9 increased significantly, and the invasion and metastasis associated protein p-STAT3, JAK2, vimentin were significantly decreased.ConclusionThe expression of IL-27 specific receptor WSX-1 in pancreatic cancer cells was very low, and IL-27 had no obvious direct effect on pancreatic cancer cells. U937 can be induced into macrophages in vitro, and by co-culture with pancreatic cancer cells, we can study the interactions between macrophages and pancreatic cancer cells. IL-27 could convert M2 type macrophages into M1 type in vitro, and indirectly affect the biological behaviors of pancreatic cancer cells through the macrophages.