| Background and objectiveGastric cancer is the second leading cause of cancer-related mortality and one of the most common cancer globally, Study found that tumor progression and metastasis in patients with gastric cancer is the leading cause of death. Wnt signaling pathway is a class of signaling systems on growth and proliferation of embryonic cell differentiation.in recent years, it has became the focus of research, there were reports showing Wnt signaling pathway participated in the development of gastric cancer, However, studies in the Wnt signaling pathway related to the metastasis and malignant degree of gastric cancer are rare reported. The study will explore the function of the key downstream molecules of Wnt signaling pathway TCF-4 and its target genes immune globulin factor 2 (ITF2)and CD44v9 in gastric cancer, espercially analysis the relationship between the above factors and the invasion or metastasis of cancer cells, provide more credible arguments and then offer a new theoretical basis for the pathogenesis, diagnosis, prognosis and treatment of gastric cancer.Material and methodDetecting the metastasis ability of gastric cancer cells MGC-803, MKN-45, SGC-7901, HSC44-PE and 44As3 by wound healing assay, detecting the TCF-4 expression levels in gastric cancer cell line by western blot; constructing the plasmid system of TCF-4 and using iCRT-14 (a kind of small molecule inhibitors of Wnt signaling); wound healing assay to verify the status of the Wnt signaling pathway on tumor cell invasion and metastasis; finally, collecting paraffin block specimens which include 83 cases primary tissue,47 cases lymph node metastasis loci and 20 cases of benign, detecting the expression of TCF-4, CD44v9 and ITF2, and analyze the correlation with clinical parameters.ResultsThe expression of TCF-4, ITF2, CD44v9 in gastric cancer:1. TCF-4 was over-expressed in the malignant tissues than benign tissues (Z=-3.829 P=0), the same result was found in immunofluorescence test, the fluorescence intensity in gastric cancer was significantly higher than adjacent tissues and gastritis (P<0.05), and its expression in lymph node metastasis and the primary had no stastatic difference (Z=-0.239, P=0.811); CD44v9 was overexpressed in the malignant tissues than benign tissues (Z=-2.547 P=0.011), and it expression in lymph node metastasis is significantly lower than the primary (Z=-4.498 P=0); in the 42 cases if 83 specimens, ITF2 was overexpressed in the malignant tissues then benign tissues (Z=-2.401, P=0.016).The relationship between the expression levels of TCF-4, ITF2 and gastric cancer cell invasion and metastasis ability:1. The wound healing assay found 44As3 had the fastest invasion ability, SGC-7901 was the lowest, TCF-4 expression was detected by western blot in all gastric cancer cells which found that the protein level of TCF-4 was related to metastasis ability and both higher than GES-1 (P<0.05).2. When TCF-4-plasmid successfully transfected into SGC7901, with increased expression of TCF-4, the metastasis was significantly increased as well, add different concentration of small molecule inhibitors into 44As3, with the concentration of the drug increaseed, the level of expression of ITF2 trend, especially concentration in 25nmol/ml, and metastatic ability correspondingly decreased (P<0.05).3. Among the 44As3, HSC44-PE and GES-1 cells, the ITF2 protein level was higher in fast one (P<0.05).The relationship between expression of TCF-4, CD44v9 and ITF2 with clinicopathological characteristics:1. Statistical analysis of association of TCF-4 expression with clinicopathological characteristics revealed that expression of TCF-4 was associated with TNM stage, tumor volume, lymph node metastasis and invasion (P<0.05); its was not statistically different with tumor position, age, sex and differentiation degree.2. Statistical analysis of association of CD44v9 expression with clinicopathological characteristics revealed that expression of CD44v9 was associated with TNM stage, lymph node metastasis and invasion (P<0.05); expression of ITF2 was not statistically different with tumor position, volume, age, sex and differentiation degree.3. Statistical analysis of association of ITF2 expression with clinicopathological characteristics revealed that expression of ITF2 was associated with TNM stage, lymph node metastasis and invasion (P<0.05); expression of ITF2 was not statistically different with tumor volume, position age, sex and differentiation degree.Conclusion1. In cell experiments, it was found higher metastatic potential cells with higher expression levels of TCF-4, also found the ability of tumor cell invasion could change when Wnt signaling pathway activation status were changed.2. The downstream key factor TCF-4 in Wnt pathway were significantly up-regulated in gastric cancer, suggested that Wnt pathway is actually active in gastric cancer. At the same time, the TCF-4 expression is related to tumor invasion and metastasis.3. Activation of Wnt pathway led activation of the transcription factor TCF-4, and then its target genes ITF2, CD44v9 were activated, which given cancer cell a strong ability of invasion and metastasis, it means that members of the pathway may be involved in the occurrence and development of gastric cancer, and become indicators for monitoring progress. |
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