The Change Of Expression Level Of Epithelial Cell Adhesion Molecule In Colorectal Cancer And Its Significance

BackgroundColorectal cancer(CRC)is a general term for colon cancer and rectal cancer.The colon is divided into ascending colon,transverse colon,descending colon,and sigmoid colon.Most of them are fixed in the posterior wall of the abdomen.The malignant tumors in this part are called For colon cancer.At present,colorectal cancer has ranked third in the incidence of malignant tumor diseases in the world,especially with the continuous improvement of the material living standards of Chinese people,eating habits tend to be high-fat,highprotein and low-fibrosis.Thus the incidence of coloretal cancer is increasing day by day,and the age of patients tends to be younger.With the innovation of diagnostic techniques and therapeutic methods,and the application of molecular targeted drugs,it provides more effective treatment for colorectal cancer,its mortality rate is still high.The current challenge is that the molecular mechanisms involved in the development of colorectal cancer are still unclear.With the recent revelation of the relationship between Ep CAM and tumorgenes,it provides a promising research direction for us to explore the pathogenesis of colorectal cancer and to find new biotherapeutic targets.Ep CAM is a transmembrane glycoprotein,also known as leukocyte differentiation antigen 326,membrane glycosylation protein,tumor-associated calcium signal transduction molecule.Ep CAM not only participates in epithelialspecific cell-cell adhesion,but also regulates normal biological functions such as signal transduction,migration,proliferation and differentiation in cells.In addition,studies have shown that Ep CAM can be widely expressed in rapidly growingepithelial cell-derived tumors,such as colorectal cancer,lung cancer,esophageal cancer,liver cancer,breast cancer,ovarian cancer,prostate cancer and pancreatic cancer.There was a negative correlation with the patient's prognosis.Other studies have shown that Ep CAM is highly expressed in undifferentiated embryonic stem cells,and thus can be used as one of the cell surface molecular markers for stem cell screening.In addition,Ep CAM is involved in the regulation of the Wnt/?-catenin signaling pathway,which plays a crucial role in the development of tumors.Therefore,the expression level of Ep CAM may be closely related to the occurrence and development of tumors.Another study suggests that Ep CAM-positive cells can be used as one of the specific molecular markers of cancer stem cells,and it is expected to become one of the early diagnostic indicators for tumor stem cell screening markers and tumors.At present,the role of Ep CAM in the development of colorectal cancer has yet to be elucidated.Therefore,this study explores the high risk factors of colorectal cancer in Chinese,from pathology and molecular biology to study Ep CAM in colorectal cancer.The expression level and its clinical significance are discussed in depth,in order to provide Ep CAM as a molecular marker for the development of colorectal cancer,providing theoretical support for early diagnosis,prognosis,and development of targeted drugs towards colorectal cancer.Aim of the studyTo clarify the expression of Ep CAM in colorectal cancer and its relationship with clinicopathological features of colorectal cancer;to study the molecular biological mechanism of Ep CAM in the development of colorectal cancer.MethodPart I META analysis of three biomarkers of colorectal cancer.(1)from January 1,2000 to July 1,2019,the following search terms were used to identify articles and keywords: 'Ep CAM','CD326','GA733-2','CEA','CA199','colorectal cancer' and 'epithelial cell adhesion molecule','colon rectum cancer','colorectal tumour',and a comprehensive literature search was carried out in Pubmed,Embase,Cochrane and CNKI library database.(2)according to the inclusion standard and exclusion standard,the retrieval literature is screened,the data are extracted and the literature quality is evaluated.(3)three tumor indexes of Ep CAM,CEA,CA199 were statistically analyzed,and the diagnostic value was evaluated by total sensitivity,specificity and likelihood ratio.Part II The expression and significance of epithelial adhesion molecules(Ep CAM)in the pathogenisis of colorectal cancer(1)The primary colorectal cancer tissues and corresponding adjacent tissues of the 158 patients with colorectal cancer who were the same as those in the first part of the study were collected.The expression level of Ep CAM was detected by immunohistochemical staining,and the relationship between the expression level of Ep CAM and the clinical stage and pathological grade of the patients was analyzed.(2)Furthermore,RT-PCR and Western Blot analysis were performed on colorectal cancer tissues and adjacent tissues to verify the transcription and translation levels of Ep CAM.Part III Ep CAM regulates the expression of CDHR5,which affects the biological characteristics of colorectal cancer cells through the ?-catenin signaling pathway.(1)Ep CAM overexpression lentiviral vector was transduced into SW480 and SW1116 colorectal cancer cell lines.SW620 and LOVO colorectal cancer cell lines were transduced with sh RNA targeting Ep CAM.The expression levels of Ep CAM m RNA and protein in transduced cell lines were verified by RT-PCR and western blot.(2)The effects of Ep CAM on colorectal cancer cell proliferation,migration,apoptosis and invasion were mainly analyzed.(3)The molecular mechanism of Ep CAM regulating colorectal cancer cells was discussed and analyzed in depth.(4)Inhibition of ?-catenin reversed the effect of Ep CAM on CDHR5 overexpression.(5)Overexpression of CDHR5 can eliminate the effect of Ep CAM on migration and invasion of colorectal cancer cells.(6)Establish a subcutaneous xenograft model in nude mice to observe whether in vivo low expression of Ep CAM can slow down the development of tumors.ResultsPart I META analysis of three biomarkers of colorectal cancer.(1)After literature retrieval,a total of 14 literatures were included in the data analysis.The sensitivity,specificity,positive predictive value,negative predictive value and DOR value were 0.79(0.61,0.90),0.95(0.75,0.99),15.5(2.7,88.6),0.26(0.15,0.45)and 35(8,145)respectively.These results prove that Ep CAM has high clinical value in the diagnosis of colorectal cancer?(2)Furthermore,the CEA,CA199 and Ep CAM indexes were compared,and the sensitivity and specificity were compared by Bayesian mesh META analysis.According to the results,the highest sensitivity was CEA and Ep CAM,the lowest was CA199.The highest specificity was Ep CAM and CA199,the lowest was CEA.According to the sensitivity and specificity,Ep CAM is the best in the diagnosis of colorectal cancer.Part II The expression and significance of epithelial adhesion molecules(Ep CAM)in the pathogenisis of colorectal cancer1.Immunohistochemical staining showed that the positive expression rate of Ep CAM in cancer tissues was as high as 91.2% in the patients with colorectal cancer,and the expression level of Ep CAM was significantly higher than that in adjacent tissues.The difference was statistically significant.2.For the expression of Ep CAM,it does not relate to the patient's gender,age and other characteristics.In colorectal cancer,the detection rate of Ep CAM is relatively high.Part III Ep CAM regulates the expression of CDHR5,which affects the biological characteristics of colorectal cancer cells through the ?-catenin signaling pathway.1.Western blot was used to detect the expression of Ep CAM protein in colorectal cancer cell lines.It was found that the and protein expression of Ep CAM was up-regulated in tumor cells.2.sh RNA-mediated Ep CAM down-regulation inhibits colon cancer cell proliferation and induces apoptosis.3.sh RNA-mediated Ep CAM down-regulation inhibit migration and invasiveness of colorectal cancer cells.4.Down-regulation of Ep CAM expression can significantly reduce the expression level of ?-catenin,and we found that the expression level of CDHR5,which is a negative regulator of ?-catenin,is up-regulated.5.Over expression of Ep CAM promotes the proliferation of SW480,SW1116 and down-regulation of CDHR5.6.Over expression of CDHR5 can reverse the increase in cell proliferation,migration and invasion caused by Ep CAM over expression.7.Low expression of Ep CAM can slow the disease progression of xenografts in nude mice.ConclusionThe expression of Ep CAM is elevated in colorectal cancer tissues,and its expression level can be used as an indicator for judging the severity of colorectal cancer patients.Ep CAM over expression can promote the growth of colorectal cancer cells,enhance their migration and invasion ability,and interfere with Ep CAM may play a regulatory role in the proliferation and apoptosis of colorectal cancer cells.Therefore,Ep CAM can be used as a target for the treatment of colorectal cancer.This paper reveals that Ep CAM has important scientific research value,provides more theoretical basis for further understanding the occurrence and development of colorectal cancer,and provides a reliable target selection for the development of effective drugs.