Biological Information Analysis And Functional Exploration Of ICAM-1 Promoting Gastric Cancer Metastasis

Objective: Gastric cancer(GC)is a malignant tumor with high recurrence of metastasis and complex metastasis mechanisms.However,its metastasis mechanism is obscure.Intercellular adhesion molecule-1(ICAM-1;CD54)is an immune inflammatory factor which has attracted much attentions in recent years.ICAM-1 plays an important role in leukocyte adhesion by binding to lymphocyte function-associated antigen-1(LFA-1).In addition,ICAM-1 can promote tumor cell epithelial-mesenchymal transition(Epithelial-mesenchymal transition,EMT)process and mediate cancer invasion and metastasis.But whether ICAM-1 is involved in the regulation of GC proliferation and metastasis and its molecular mechanism remains unclear.This thesis aims to explore the potential value of ICAM-1 as a biomarker for GC based on biological databases,and to verify the role of ICAM-1 in GC proliferation and metastasis through in vitro and in vivo experiments.Methods: 1.Biological information analysis.The TCGA database was used to analyze the difference expression of ICAM-1 between GC tissues and normal tissues;The relationship between ICAM-1 gene and prognosis of GC patients was analyzed by Kaplan-Meier survival curve;Clinicopathological analysis was used to explore the association between ICAM-1gene and clinicopathological features of GC patients.Based on GO and KEGG,ICAM-1 was subjected to functional GSEA and GSVA.WGCNA was used for exploring genes interacting with ICAM-1.2.In vitro experiments.Expression levels of ICAM-1 and EMT markers(E-cadherin,Vimentin)in were detected by Western blot assay in various GC cell lines.si RNA was used to suppress ICAM-1 gene.Western blot was also used to detect the expression levels of ICAM-1 and EMT markers in the ICAM-1 gene silencing group.Transwell assay was performed to compare the migration ability of HGC-27 after stimulation with s ICAM-1.Cell migration abilities was analyzed by Transwell assay after reducing ICAM-1 with si RNA.3.In vivo experiments.Over-expression of ICAM-1 were prepared with lentivirus infection in MKN-45 GC cell line.Cells were injected subcutaneously to mouses and tumor variations were observed,recorded and measured.Data was analyzed and plotted.Results: Bioinformatics analysis showed that the expression of ICAM-1 in gastric cancer was higher than that of paracancer tissues.ICAM-1 expression was not related to the prognosis of gastric cancer,but was related to the grade of gastric cancer(P<0.01).ICAM-1was an immune and inflammatory response factor.There was a significant correlation between ICAM-1 and mesenchymal markers(r=0.43,p<0.01).ICAM-1 was involved in processes such as leukocyte adhesion and lymphocyte activation.In vitro experiments,the migration of gastric cancer cells was increased under the stimulation with s ICAM-1;the expression of ICAM-1 protein in gastric cancer cells was negatively correlated with E-cadherin and positively correlated with N-cadherin.After silencing of ICAM-1 by RNAi,these above phenomena was all attenuated.In vivo experiments,the subcutaneous tumor volume of gastric cancer cells over-expressing ICAM-1 gene was larger than control group(P<0.01).Conclusion: ICAM-1 is relatively highly expressed in gastric cancer and is related to the grade of gastric cancer.ICAM-1 promotes gastric cancer proliferation and metastasis via EMT process.The results of this study can provide a scientific basis for ICAM-1 as a potential molecular target and biomarker for gastric cancer.