Expression of SORT1 in Gastric Cancer Tissue and Its Effect on Gastric Cancer Cell Biology

Objective To investigate the expression of SORT1 in the gastric cancer tissue and analyze its relationship with clinical prognosis of patients as well as the pathways and mechanisms involved in gastric cancer progression.Methods The Gene Expression Profiling Interaction Analysis database,Western blot,and immunohistochemistry were employed to predict and analyze the expression of SORT1 in the gastric cancer and the adjacent tissue.The clinical case information of 109 patients who underwent radical surgery for gastric cancer in the First Affiliated Hospital of Bengbu Medical University from April 2015 to April 2017 was collected to analyze the relationship of SORT1 with the clinicopathological parameters and prognosis of the patients.Cell proliferation was detected by the CCK-8 assay and colony formation assay,while cell migration and invasion were assessed by the scratch assay and Transwell assay,respectively.Western blot was employed to determine the expression of proteins related to epithelial-mesenchymal transition(EMT)in gastric cancer cells,followed by further analysis on molecular mechanism through which SORT1 regulates EMT in gastric cancer cells.Results Western blot and immunocytochemistry results showed that SORT1 was highly expressed in the gastric cancer tissue(P=0.003,P<0.001),which was positively correlated with malignant progression of tumors(all P<0.05).The Kaplan-Meier survival analysis revealed shortened postoperative survival periods for the patients with high expression of SORT1(P<0.001).The Cox regression model indicated that SORT1 expression was an independent risk factor affecting the 5-year survival rate after surgery for gastric cancer patients(P<0.001).Up-regulation of SORT1 expression promoted the proliferation,migration,invasion,and EMT of gastric cancer cells(all P<0.05),while down-regulation of SORT1 showed the opposite effects(all P<0.05).Western blot results showed that high expression of SORT1 promoted the expression of β-catenin,cyclin D1,and c-Myc(all P<0.05).Moreover,in vitro use of the Wnt/β-catenin pathway inhibitor(XAV939)effectively suppressed the EMT enhancement caused by high expression of SORT1 in gastric cancer cells(all P<0.05).Conclusions SORT1 is highly expressed in gastric cancer and affects patients' postoperative survival periods.It is involved in the proliferation,migration,and invasion of gastric cancer cells and may promote the EMT of gastric cancer cells by activating the Wnt/β-catenin pathway.