Siglec-15 In Colorectal Cancer Tissues Express Characteristics And Biological Function Research

The human body is a multicellular organism that is composed of different types of cells and is subject to strict regulation.However,when some cells,such as cancer cells,escape from the constraints of this cellular society,it will multiply infinitely and invade other parts of the body.From 1990 to 2017,tumors rose from the sixth leading cause of disability-adjusted life years to the second.Although the level of treatment for tumors has gradually improved,the underlying cause of tumors has not been explained.Sigelc15 as a member of the Siglecs family is a classic sialic acid binding protein,a type I transmembrane protein.Previous studies on Siglec-15 have focused on osteoclast differentiation and bone remodeling,although its immune function has been explored but not much.As an immunosuppressive molecule,Siglec-15,which was expressed on macrophages in the first half of 2019,is a potential target,making it a research hotspot.However,the effect of its expression on tumor cells on tumor cells remains to be studied.Objective:To investigate the effect of Siglec-15 on the biological function of colorectal cancer cells and study its mechanism of action.Methods:1.By immunohistochemical staining of tumor tissues and normal tissues,the difference in expression of Siglec-15 in tumor tissues and normal tissues was studied.2.To detect the difference of Siglec-15 expression in normal colorectal cell lines and various colorectal cancer cells.3.Construct Siglec-15 low-expressing cell line.4.The CCK8 method was used to detect the proliferation levels of the control group and the Siglec-15 low expression group,and the cycle and apoptosis of the two groups were detected by flow cytometry.5.Transwell was used to detect differences in migration and invasion between the two groups.6.Western blot was used to detect the expression of key proteins affecting tumor cell proliferation,invasion and migration.7.Further validation in vivo experiments to construct a subcutaneous tumor-bearing mouse model.Results:1.Immunohistochemical staining was performed on 108 colorectal cancer tissues and 90 adjacent tissues.The experimental results showed that the expression level of Siglec-15 in colorectal cancer tissues was significantly higher than that in adjacent tissues.Significance(P<0.05).2.Using Western blot to detect the expression levels of Siglec-15 in normal colorectal cells NCM460 and colorectal cancer cells HCT116,RKO,HCT8,and SW480.The results show that the expression level of Siglec-15 in normal colorectal cancer cell lines is lower than that in colorectal cancer cell lines The difference between the two groups was statistically significant(P<0.05).3.A stable low-expression colorectal cancer cell line of Siglec-15 was successfully constructed by lentivirus,and the cell proliferation ability was detected by CCK8 method.The results showed that at 24h,72h,96h after seeding,the proliferation level of the Siglec-15 low-expression group was lower than that of the control group,and the difference between the two groups was statistically significant(P<0.05).4.Analysis of the Transwell results of the Siglec-15 stable low expression group and the control group.The number of migrating and invading cells in the Siglec-15 low expression group was less than that in the control group.The difference between the two groups was statistically significant(P<0.05).5.Western blot and IHC were used to detect the protein expression levels and gene transcription levels of p53,p21,Bcl-2,Bax,and E-cad in the two groups of cells.The results showed that compared to the control group,p53 in the Siglec-15 low expression group,p21,Bax,E-cad protein expression and gene transcription level increased,Bcl-2 decreased,and the difference between the two groups was statistically significant(P<0.05).6.The results of subcutaneous tumor-bearing experiment in nude mice showed that the tumor size and growth rate in the siglec-15 low-expression group were significantly lower than those in the control group(P<0.05).Western blot and IHC were used to detect the siglec-15 and p53 protein expressions in the two groups.The results showed that the siglec-15 protein expression level in the low-expression group was lower than that in the control group,and the p53 protein expression level was higher than that in the control group,with statistically significant results(P<0.05).Conclusions:The expression level of Siglec-15 in colorectal cancer tumor tissues and tumor cells is significantly higher than that in normal tissues and cells.After the Siglec-15 expression of tumor cells is reduced,it can inhibit the expression of Bcl-2 by promoting the expression of p53 and p21.Promote the expression of Bax and E-cad,affect the proliferation,apoptosis,migration and invasion of colorectal cancer cells,and inhibit the growth of subcutaneous tumors in mice.