The Tumor Suppressor Gene Vps33b Regulates The CXCL12/CXCR4 Pathway By Altering ANXA2 To Affect Tumor-associated Macrophages And The Prognosis Of Gastric Cancer

Objective: Gastric cancer is one of the most common gastrointestinal tumors in the world.As China has a high incidence of gastric cancer,about half of the world’s gastric cancers occur in China.How to break through the current bottleneck of gastric cancer treatment is a hot issue in the research of advanced gastric cancer.This study aims to explore the effect of Vps33 b on the immune microenvironment of gastric cancer and its impact on prognosis.Methods:1.Use immunohistochemistry to detect the expression of VPS33 B in tumor tissue specimens from gastric cancer patients,and score it by immunohistochemistry.2.In gastric cancer cell lines SGC7901 and MKN45,transfect the plasmid carrying the Vps33 b gene with lentivirus technology.Then,use antibody chips to detect the expression of various cytokines in the cell supernatant,and use immunoblotting to detect the expression level of the relevant protein(CXCL12)in the cell.3.Search the database to explore the expression of VPS33 B and the difference between different chemokines.Relationship.4.ELISA was used to test the expression level of CXCL12 in the cell supernatant between the Vps33 b overexpression group and the control group.5.Using immigration to detect the chemotactic ability of the VPS33 B overexpression group and the control group on THP1 cells Differences.6.Using subcutaneous tumor formation experiments in mice,we study its role in the development of gastric cancer and its molecular mechanism in vivo experiments,and to verify the results of in vitro experiments.Results:1.Immunohistochemical results of cancer nests and paracancerous sections of52 patients with gastric cancer who did not receive chemoradiation showed that the expression site of VPS33 B was cytoplasm,normal gastric crypt glands and vascular smooth muscle were expressed,and cancer tissues were basically not expressed.The analysis found that the expression of VPS33 B in gastric cancer tissues was significantly lower than that in paracancerous gastric tissues(P <0.0001).2.The public database TIMER found that the expression of VPS33 B in gastric cancer wasnegatively correlated with immune infiltration of macrophages(partial correlation regression coefficient =-0.248),and a negative correlation with the expression of chemokine CXCL12(partial correlation regression coefficient =-0.236).3.Take two gastric cancer cells for VPS33 B overexpression,and perform tissue chip detection on the cell supernatant.It was found that CXCL12 in the VPS33 B overexpression group was significantly reduced compared to the negative control group.4.Cell immigration experiments were performed on the two gastric cancer cell lines VPS33 B overexpression group and the negative control group and THP1 cell line,and the number of migration in the VPS33 B overexpression group was significantly reduced(P <0.001).Western-blot and ELISA showed that the overexpression of VPS33 B had a decreasing effect on CXCL12 both in the cell and in the secretion level.5.IP experiments and proteins on VPS33 B were performed intracellular It was found that the interaction between VPS33 B and ANXA2 was found in the profiling,and the overexpression of VPS33 B can reduce the expression of ANXA2,and thus the expression level of CXCL12 expression levels in mouse tissue and serum.6.By subcutaneous tumor formation experiments in nude mice,it was found that the overexpression of VPS33 B can reduce the expression of CXCL12 in mouse tissues and serum.Conclusion : The tumor suppressor gene VPS33 B can regulate the CXCL12/CXCR4 pathway by reducing the expression of ANXA2,and regulate the chemotactic level of tumor-associated macrophages(TAM)in the tumor microenvironment,thereby affecting the prognosis of gastric cancer patients.