The Expression And Significance Of MUC4 In Colorectal Cancer And Its Effect On The Epithelial-mesenchymal Transition

BackgroundColorectal cancer is one of the most common malignancies,About 1.2 million patients worldwide are diagnosed with colorectal cancer each year,and more than 600,000 patients die directly or indirectly from colorectal cancer.MUC is a kind of glycoprotein produced by MUCosal tissue.There are three main types: secretory MUCosin,soluble MUCosin and transmembrane MUCosin.MUC4 is a member of the transmembrane MUCous family,mainly in the gastric mucosa、tracheal mucous membrane、intestinal mucosa and other epithelial tissues.It plays a role of protection and lubrication of epithelium in normal cells,and can reduce tumor cell adhesion force 、 participate in regulating cell adhesion,signal transduction and the invasion and metastasis and so on in tumor cells.Epithelial-mesenchymal Transition refers to the transformation of a polar epithelial cell to a mesenchymal cell with motor ability.It gives cells the ability to move and invade.It exists in embryo development 、 many physiological and pathological processes,involving complex signaling pathways.After that,we find it was closely related to the metastasis of tumor cells.ObjectiveThe purpose of this study was to investigate the expression and significance of MUC4 in colorectal cancer.At the same time,we further studied the effect of MUC4 on interepithelium transformation,and provided a new target for clinical diagnosis and treatment of colorectal cancer.MethodsA total of 38 tissue samples with colorectal cancer and adjacent fresh surgical specimens were collected from the first affiliated hospital of zhengzhou university.The morphology of 38 cases of colorectal cancer and adjacent tissue frozen sections were detected by HE staining.Fluorescence quantitative PCR and immunofluorescence assay were used to detect the expression of MUC4 in cancer and adjacent tissues and its relationship with clinicopathological parameters.qRT-PCR detection of MUC4 siRNA interference effect.The expressions of MUC4,E-cadherin and Vimentin were detected by Western Blot test.The morphological changes of the two groups were observed by inverted microscope.Transwell cell invasion experiment was conducted to observe the effect of different expressions of MUC4 on the invasion ability of cells.CCK8 test was used to detect cell proliferation activity.Results1 、 Tissue HE staining : The histopathological type was in line with expectations and the cell morphological structure was intact;2、 The immunofluorescence and qrt-pcr experiments of tissue samples: MUC4 is poorly expressed in cancer tissues and is highly expressed in adjacent tissues(P﹤0.01).The expression level of MUC4 was not related to gender,age,site(P﹥0.05),but was related to lymph node metastasis(P﹤0.01).MUC4 protein expression in Ⅰ-Ⅱ period(0.036±0.007)is higher than Ⅲ-periodⅣ(0.029±0.011)(P﹤0.01).The expression of MUC protein in the absence of lymph node metastasis group(0.037±0.008)was higher than that in the lymph node metastasis group(0.028±0.013)(P﹤0.01);3 Cell strain test:The siRNA was transfected with SW620 cells via liposomes 2000.The epithelial-mesenchymal transition occurred in SW620 cells.Compared with the control group,the expression of MUC4 and epithelial marker E-cadherin in the experimental group were decreased and Vimentin expression of interstitial marker was increased;4、Inverted microscope results :The cells of SW620(transfection MUC4 siRNA)were transformed from ovoid to spindle,cell polarity disappeared,cell contact was loose and disorderly.5、 Transwell cell invasion experiment: compared with the control group,the number of invasion cells of SW620(transfected MUC4-sirna)increased significantly(P﹤0.01).6、 CCK8 test: compared with the control group,the number of stained cells of SW620(transfected MUC4-sirna)increased significantly.Conclusions1.The immunofluorescence and qRT-PCR test of colorectal cancer specimens showed that the low expression of MUC4 is related to the invasion and metastasis of tumor cells,and MUC4 is expected to be a marker for the prognosis and prognosis of patients with colorectal cancer.2.Cell line experiments show that MUC4 mucin low expression could induce epithelial mesenchymal transition in(EMT)SW620 cells,this provides an experimental basis for further understanding the invasion and migration mechanism of colorectal cancer,and provide new targets for colorectal cancer treatment.