Expression And Role Of Phosphorylated RelA/p65 Ser536 In Gastric Cancer

[Objective] Studies have shown that NF-?B is closely related to tumorigenesis,development,and invasion and metastasis.It is generally believed that NF-?B mainly plays an anti-apoptotic and tumor-promoting role,so NF-?B is used as a therapeutic target and its inhibitors are used to treat cancers.However,thousands of NF-?B inhibitors fail to exert the expected clinical effect.With the deepening of research,it was found that the phosphorylation status in different sites of NF-?B can show diametrically opposite functions.Abroad studies have shown that NF-?B Rel A/p65 536 serine site phosphorylation(p-p65 Ser536)has an inhibitory effect on colorectal cancer,breast cancer,and prostate cancer.This subject studies the expression and role of p-p65 Ser536 in gastric cancer.[Methods] The expression of NF-?B p-p65 Ser536 in normal gastric mucosa,paracancerous tissues,and gastric cancer was detected by tissue microarray combined with immunohistochemistry(SP method)and its clinical significance was analyzed;Western blot was used to detect the expression of NF-?B p65 Ser536 in gastric cancer cells and immortalized gastric mucosa epithelial cells;using indirect immunofluorescence staining detection of NF-?B p65 Ser536 expression and observating the situation of its phosphorylation status into the nucleus;establishing the model of NF-?B p65 536 serine site phosphorylated and non-phosphorylated cells and detecting the effect of NF-?B p-p65 Ser536 phosphorylation on the migration and invasion in gastric cancer cells by Transwell migration,invasion chamber assay and scratch test.[Results]1.Immunohistochemistry results of tissue microarray showed that NF-?B p-p65 Ser536 protein was expressed in cytoplasm and nucleus,and it was highly expressed in non-gastric tissues.The expression of NF-?B p-p65 Ser536 protein was significantly decreased in gastric cancer tissues.Their positive rate respectively were 83.6 %(107/128)and 36.8 %(71/193),and the difference has statistically significant(P<0.05).In addition,the positive expression rate of p-p65 Ser536 in gastric cancer decreased with the degree of differentiation,and the difference was statistically significant.There was no significant correlation between the expression of NF-k B p-p65 Ser536 and the gender,age,and tumor size of gastric cancer,but it was related to the pathological grade,lymph node metastasis,and clinical TNM staging of gastric cancer(P<0.05).2.Western-blot results showed that the expression level of NF-?B p-p65 Ser536 protein in gastric cancer MGC-803 and SGC-7901 cells was significantly lower than that in immortalized gastric epithelial GES-1 cells(P<0.05),and the expression of p-p65 Ser536 in mgc-803 cells with low differentiation was significantly lower than that in sgc-7901 cells with moderate differentiation(p <0.05).3.Immunofluorescence results showed that the level of p65 Ser536 phosphorylation protein into the nucleus in the two gastric cancer cells was significantly reduced compared with immortalized gastric mucosal cells.4.Transwell migration,invasion assay and scratch test results show that NF-?B p-p65 Ser536 may inhibit the migration and invasion of gastric cancer cells.[Conclusions] 1.The expression of NF-?B p-p65 Ser536 protein in gastric cancer was decreased.The expression of NF-?B p-p65 Ser536 protein was related to the degree of differentiation of gastric cancer,lymph node metastasis and TNM staging.2.NF-?B p-p65 Ser536 may inhibit the migration and invasion of gastric cancer cells.