Correlation Of ANGPTL4 Expression With Treg Cells And M2-Type Macrophages In Colorectal Cancer

Background:China is one of the high incidence areas of colorectal cancer in the world.In recent years,the incidence of colorectal cancer has increased significantly,and the treatment of advanced colorectal cancer is very limited.Therefore,it is necessary to find an effective treatment strategy.Angiopoietin-like 4 is a new kind of secreted glycoproteins discovered in recent years.Studies have found that C-ANGPTL4 plays an important role in regulating tumor growth,angiogenesis,and cell transendometrial metastasis.At the same time,the Regulatory T cell(Treg)and M2 macrophages have also been gradually proved to promote tumor growth.Treg cells are a group of negative regulatory cells with special inhibitory effects.Therefore,the study on ANGPTL4,Treg cells and M2 macrophages may provide new ideas for targeted therapy and immunotherapy of colorectal cancer in the future.Objective:1.To investigate whether the expression of ANGPTL4 is higher in colorectal cancer cells.2.To study the expression of ANGPTL4 in different stages of colorectal cancer and adjacent tissues;3.To study whether the expression of ANGPTL4 in colorectal cancer is related to the infiltration level of Treg cells and M2 macrophages in tumors.Methods:Firstly,human and mouse eolorectal eancer eells HCT116 and MG38 were selected in the in vitro experiment.The expression of ANGPTL4 in human and mouse colorectal cancer cells was detected by immunofluorescence method.Secondly,peripheral blood serum of 70 patients with colorectal cancer and 10 healthy People was collected as control group.ANGPTL4 eoncentration in serum of these two groups was detected by ELISA method.Expression of ANGPTL4,Foxp3 and CD 163 in colorectal cancer was detected by immunohistochemistry and western blot,and the correlation was analyzed by statistical method.Finally,recombinant ANGPTL4 protein was added into mouse spleen cell cultire system.After stimulated for 72 hours and 48 hours,the proportion of Treg cells and M2 macrophages was detected by flow cytometry.Results:1.ANGPTL4 was expressed in human and mouse colorectal cancer cells HCT116 and MC38 to varying degrees.2.Compared with healthy group,serum ANGPTL4 level in colorectal cancer patients was significantly higher,and the serum ANGPTL4 level in Dukes CD patients was significantly higher than that in AB patients.3.Compared with paracancer tissues,expression of ANGPTL4 and the infiltration of Treg cells and M2 macrophages in colorectal cancer tissues were significantly upregulated.Expression of ANGPTL4 and the infiltration of Treg cells and M2 macrophages in Dukes CD phase were significantly higher than those in Dukes AB phase.4.Correlation analysis showed that both the level of ANGPTL4 in tissues and serum were significantly positively correlated with the infiltration of Treg cells and M2 macrophages in tissues.5.Addition of ANGPTL4 recombinant protein increased the proportion of Treg cells and M2 macrophages,indicating that ANGPTL4 recombinant protein may promote the induced differentiation of Treg cells and M2 macrophages.Conclusion:ANGPTL4 is expected to be a tumor marker for colorectal cancer diagnosis.The induction of Treg cells and M2 macrophages may be one of the mechanisms by which ANGPTL4 promotes tumor progression.