| Objective:The expression,function and mechanism of FZD8 in gastric cancer remain unclear.To investigate the expression and biological function of FZD8 in gastric carcinoma and the molecular biological mechanism by which FZD8 affects the biological function of gastric carcinoma.Finally,the effect and mechanism of FZD8 on the biological behavior of gastric cancer cells were investigated.Methods:First,the expression levels of FZD8 mRNA and protein in gastric cancer tissues were detected by RNA-seq,and the effects of FZD8 and related signaling pathways on the invasion and metastasis ability of gastric cancer were analyzed by bioinformatics.The clinicopathological characteristics of 60 gastric cancer patients were collected and sorted out,and the direct relationship between FZD8 expression and clinicopathological characteristics of patients was analyzed by univariate and multivariate regression analysis.The overall survival rate of patients with relatively high and relatively low expression of FZD8 was analyzed by survival analysis.Second,the results of qRT-PCR and Western blot showed that the expression of FZD8 mRNA and protein in gastric cancer cells was significantly higher than that in glandular cells of normal gastric tissues.The results of cell function experiments showed that interfering with the expression of FZD8 in gastric cancer cells would reduce the cell invasion and metastasis ability of gastric cancer cells.Conversely,overexpression of FZD8 in gastric cancer cells would promote the invasion and metastasis ability of gastric cancer cells.Further,the orthotopic liver metastasis model experiment of gastric cancer in nude mice showed that compared with the interfering control group,the interfering FZD8 expression group significantly inhibited the liver metastasis of gastric cancer.Tumor immunohistochemistry confirmed that the expression of MMP2 and MMP9 was significantly reduced.Therefore,in vivo and in vitro studies showed that interfering with FZD8 expression could inhibit the invasion and metastasis ability of gastric cancer cells.Third,in order to further explore the molecular biological mechanism of FZD8 regulating the invasion and metastasis ability of gastric cancer cells,the changes of β-catenin signaling pathway and its downstream protein expression in gastric cancer cells were detected by Western blot.Results:First,the results of RNA-seq showed that FZD8 mRNA and protein were significantly overexpressed in gastric cancer tissues.Further analysis of the relationship between FZD8 expression and pathological characteristics of clinical patients showed that high FZD8 expression was significantly correlated with lymph node metastasis,distant metastasis and clinical stage of tumors.Kaplan-Meier analysis showed that patients with high FZD8 expression were more likely to present than those with low FZD8 expression.Short overall survival.Rregression analysis showed that FZD8 was an independent predictor of poor prognosis in gastric cancer patients.In conclusion,these data suggest that abnormally high expression of FZD8 is closely associated with poor prognosis in gastric cancer.Second,the results of qRT-PCR and Western blot showed that the expression of FZD8 mRNA and protein in gastric cancer cells was significantly higher than that in glandular cells of normal gastric tissues.The results of cell function experiments showed that interfering with the expression of FZD8 in gastric cancer cells would reduce the cell invasion and metastasis ability of gastric cancer cells.Conversely,overexpression of FZD8 in gastric cancer cells would promote the invasion and metastasis ability of gastric cancer cells.Further,the orthotopic liver metastasis model experiment of gastric cancer in nude mice showed that compared with the interfering control group,the interfering FZD8 expression group significantly inhibited the liver metastasis of gastric cancer.Tumor immunohistochemistry confirmed that the expression of MMP2 and MMP9 was significantly reduced.Therefore,in vivo and in vitro studies showed that interfering with FZD8 expression could inhibit the invasion and metastasis ability of gastric cancer cells.Third,Western blot results showed that FZD8 regulated the β-catenin signaling pathway by altering the expression of FZD8 in gastric cancer cell lines and detecting the expression changes of β-catenin signaling pathway and its downstream target genes.In gastric cancer cells SGC-7901 and MKN-45 interfered with the expression of FZD8,the expression of β-catenin protein was significantly decreased,and the expression levels of its downstream target proteins WISP1,HoxB9 and Survivin were also downregulated.At the same time,the protein markers MMP2,MMP9 and N-cadherin related to invasion and metastasis were also down-regulated,while the protein expression of E-cadherin was up-regulated.Conversely,FZD8 protein was overexpressed in gastric cancer cell lines SGC-7901 and MKN-45 with relatively low expression of FZD8.The expression ofβ-catenin protein was significantly up-regulated,and the expression levels of its downstream target proteins WISP1,HoxB9 and Survivin were also up-regulated.At the same time,the protein markers MMP2,MMP9 and N-cadherin related to invasion and metastasis were also upregulated,while the protein expression of E-cadherin was downregulated.Conclusion:(1)The high expression of FZD8 protein in gastric cancer tissues and the high expression of FZD8 in gastric cancer tissues suggest a lower survival rate;(2)FZD8 is an independent risk factor for the invasion and metastasis of gastric cancer cells;(3)FZD8 promotes invasion and metastasis of gastric cancer cells;(4)FZD8 promotes invasion and metastasis of gastric cancer cells by activating β-catenin signal pathway. |
PDF Full Text Request