The Expression And Significance Of CSN6 And Related Molecules In The Carcinogenesis Of Sporadic Colorectal Adenoma

Objective: Colorectal cancer is one of the most common causes of gastrointestinal malignancies.In China,the morbidity and mortality are at the forefront of various malignancies and are increasing year by year.Data shows that about 80% of colorectal cancers are from the colorectal adenoma,and some scholars believe that colorectal adenoma is a precancerous lesion of colorectal cancer.However,the occurrence and development of colorectal cancer are a complex process,which including the process of ubiquitination and a variety of factors.Now there are more and more researches about the mechanism,but the specific mechanisms are not clear.CSN6 is a newly discovered tumor suppressor gene in recent years which is related with ubiquitination.As the sixth subunit of COP9,CSN6 plays an important role in maintaining the structural integrity of its complex.Regulates show that CSN6 can regulate the E3 ubiquitin ligase enzyme(E3),from which we know that CSN6 plays an important role in the regulation of polyubiquitin chain degradation and promoting the development of tumor.P-Akt is a serine/threonine kinase.As an important tumor regulator in the human body,it can regulate a variety of downstream molecules.Studies have found that CSN6 can be phosphorylated by p-Akt,from which we speculated that p-Akt may act as an upstream regulatory factor for CSN6 and regulate the expression of CSN6 by phosphorylation.In addition,as the core protein of Wnt signaling pathway,β-catenin is degraded by ubiquitination of proteasome system,and its degradation depends on ubiquitin ligase E3.The FBXW7 protein is an important subunit that constitutes the E3 ubiquitin ligase complex,which can specifically recognize a variety of proteins,including β-catenin,and induces them to ubiquitination degradation.It is known that CSN6 mediates the ubiquitinated proteasomepathway by regulating E3 ubiquitination ligase,and FBXW7 mediates its degradation as an E3 ligase subunit in the degradation process of β-catenin protein,from which we speculate in the process CSN6 may regulate the degradation of β-catenin by regulating FBXW7 and mediate the carcinogenesis of colorectal adenoma.At present,CSN6 has been paid more and more attention,but the research on it is relatively small.Until now,whether CSN6 affects the regulation of β-catenin by regulating FBXW7 and then leads to the occurrence of colorectal adenocarcinoma or not has no relevant reports.Therefore,we detected the expression of CSN6 and its related factors in normal colorectal mucosa,colorectal adenoma and adenocarcinoma by immunohistochemistry,and analyze the relationship between the expression of CSN6 and other indicators.So that we can explore their possible role in the process of carcinogenesis of colorectal adenoma,and provide a new basis for the diagnosis and treatment of colorectal cancer.Methods:1 We used immunohistochemical Elivision TMplus method to study the expression of CSN6,p-Akt,FBXW7,β-catenin and c-Myc in 40 cases of normal colorectal mucosa,100 cases of sporadic colorectal tubular adenoma with different dysplasia and 101 cases of colorectal tubular adenoma with carcinomatous changes.Then we explore the correlation between them and analyze the correlations combined with clinical pathological characteristics.2 The experimental data were analyzed by SPSS 19.0 software,such as Chi-square test,Fisher’s exact test and spearman correlation analysis.When P<0.05,the date was statistically significant.Results:1 CSN6 protein expression and its relationship with clinical pathological characteristics1.1 The expression of CSN6 in the process of colorectal adenoma carcinomatous The CSN6 protein positive reaction was localized in the nucleus and/or cytoplasm,with brown particles.Which was positive in normal tissues,colorectal adenoma and colorectal cancer tissues.The positive rate was respectively 25.00%,59.00%,78.22%,(P<0.05),from which we can know the positive rates of CSN6 in normal group,adenoma group and adenocarcinoma group were gradually increases.The positive rate of the after two groups were significantly higher than that in normal mucosa group(P<0.05),and adenocarcinoma group was significantly higher than that in normal adenocarcinoma group adenoma group(P<0.05).At the same time,the positive expression rate of CSN6 protein in adenoma tissue was related to the degree of adenoma differentiation,and the rates were gradually higher in mild,moderate and severe dysplasia group(46.88%,52.63%,80.00%).The patients with severe dysplasia were significantly higher than those with mild and moderate dysplasia(P<0.05),while the difference between the expression of mild and moderate dysplasia groups had no statistical significance(P>0.05).1.2 Relationship between the expression of CSN6 and clinical pathological characteristics In adenocarcinoma,the positive expression rate of CSN6 was correlated with tumor stage and lymph node metastasis.The positive rate of CSN6 in T1/T2 staging group was 72.46%,which was significantly lower than that in T3/T4 staging group(90.63%,P<0.05).At the same time,89.47% in lymph node metastasis group,which was significantly higher than that in non-lymph node metastasis group(71.43%,P<0.05),but not with age,sex,depth of invasion,differentiation degree and tumor location(P >0.05).2 p-Akt protein expression and its relationship with clinical pathological features2.1 The expression of p-Akt in the process of colorectal adenoma carcinomatous The p-Akt protein is positive in the nucleus and/or cytoplasm.As our datas showed that the positive expression rates of normal colorectal mucosa,adenocarcinoma and adenocarcinoma were 20.00%,44.00% and 78.22%.Respectively,adenoma and adenocarcinoma groups were significantly higher than those of normal colorectal mucosa(P<0.05).At the same time,the positive expression rate in adenocarcinoma group was significantly higher than that in adenoma group(P<0.05).While the positive expression rates in adenoma tissue with different dysplasia(37.50%,47.37%,46.67%)had no statistical significance(P>0.05).2.2 Relationship between the expression of p-Akt and clinical pathological characteristics In colorectal cancer tissue,the positive expression rate of p-Akt in the poorly differentiated adenocarcinoma group was 91.67%,which was significantly higher than that in the moderate and well differentiated adenocarcinoma group(70.77%,P<0.05).And the positive expression rate of p-Akt was also related with lymph node metastasis and tumor location.As the datas showed us,89.47% in the lymph node metastasis group was significantly higher than that in the non-lymph node metastasis group 71.43%(P<0.05).The positive rate of colon adenocarcinoma was 72.06% and the positive rate of rectum cancer was 90.91%,the difference was statistically significant(P<0.05),but not with age,sex,tumor stage and infiltration depth(P> 0.05).3 FBXW7 protein expression and its relationship with clinicl pathological features3.1 The expression of FBXW7 in the process of colorectal adenoma carcinomatous FBXW7 protein positive reaction mainly located in the nucleus,with the emergence of brown particles.Immunohistochemical results showed that the positive expression rates gradually decreased in normal colorectal mucosa,colorectal adenoma and colorectal cancer tissues(95.00%,80.00%,54.46%),respectively.The positive expression rate of adenocarcinoma group was significantly lower than that of the other groups(P<0.05),the difference between the rates of colorectal adenoma and normal colorectal mucosa group were also had statistical significance(P<0.05).In adenoma tissue,the positive expression rate of FBXW7 protein was related to the degree of differentiation,and its positive expression rate was 63.33% in severe dysplasia adenoma group,which was significantly higher than that in mild and moderate dysplasia adenoma group(P<0.05).While the difference between the expression of mild and moderate dysplasia group has no statistical significance(P>0.05).3.2 Relationship between the expression of FBXW7 and clinical pathological characteristics In adenocarcinoma,the positive expression rate of FBXW7 was only related with tumor infiltration depth.Dates showed that the positive rate of shallow depth of infiltration was 23.53%,and the positive rate of deep depth was 60.71%(P<0.05).While it had no relationship with age,sex and tumor stage,differentiation,location,lymph node metastasis(P> 0.05).4 β-catenin protein expression and its relationship with clinical pathological features4.1 The expression of β-catenin in the process of colorectal adenoma carcinomatous As the study showed that β-catenin protein positive reaction in the normal cells located in the cell membrane,while in the adenoma and adenocarcinoma cells the ectopic expression increased,mostly located in the nucleus and/or cytoplasm,with brown particles appearing.That was positively expressed in colorectal adenoma and colorectal cancer tissues.67 cases were positive in100 cases of adenoma,meaning the positive rate was 67.00%;at the same time89 cases of colorectal cancer were positive in 101 cases,the positive rate was88.12 %.In the normal colorectal mucosa the positive expressions were less,with the positive rate of 7.50%.The positive expression rate of β-catenin gradually increased in normal colorectal mucosa,adenoma with varying degrees dysplasia and colorectal carcinoma changed from adenoma(P<0.05).The adenoma group and adenocarcinoma group were significantly higher than that in normal mucosa group(P<0.05),and adenocarcinoma group was higher than adenoma group(P<0.05).The positive expression rate of β-catenin protein in adenoma tissue was related to the degree of differentiation,and its positive expression rate was 93.30% in severe dysplasia adenoma group,which was significantly higher than that in mild and moderate dysplasia adenoma group(P<0.05).While between mild and moderate group,the difference was no statistical significance.4.2 Relationship between the expression of β-catenin and clinical pathological characteristics In adenocarcinoma tissue,the positive expression rate of β-catenin had statistical significance in lymph node metastasis.97.37% in lymph node metastasis group,which was significantly higher than that in non-lymph node metastasis group(82.54%,P<0.05).But,its expression was not related with age,sex,tumor stage,differentiation,depth of invasion and tumor location(P>0.05).5 c-Myc protein expression and its relationship with clinical pathological features5.1 The expression of c-Myc in the process of colorectal adenoma carcinomatous C-Myc protein positive reaction is mainly located in the nucleus and/or cytoplasm,mainly to the nucleus,with brown particles appearing.The positive rate was 74.00% of adenoma(74/100),and 90 cases were positive in 101 cases of colorectal cancer,the positive rate was 89.11%.In the normal colorectal mucosa the expression was less,40 cases of normal tissue only 4 cases were positive expression,the positive rate of 10.00%.The positive expression rates of c-Myc in adenocarcinoma group and adenoma group were significantly higher than that in normal adenocarcinoma group(P<0.05).And the rate of adenocarcinoma group was higher than that of adenoma group(P<0.05).The positive expression rate of c-Myc protein in adenoma tissue was related to the degree of differentiation,and its positive expression rate was 90.00% in severe dysplastic adenoma group,which was significantly higher than that in mild and moderate dysplasia adenoma group(P<0.05).While the difference between the expression rates of mild and moderate dysplasia group had no statistical significance(P>0.05).5.2 Relationship between the expression of c-Myc and clinical pathological characteristicsIn adenocarcinoma tissues,the positive expression rate of c-Myc was no relationship with age,sex,tumor stage,differentiation,lymph node metastasis depth of invasion and tumor location(P> 0.05).6 In the process of carcinogenesis of sporadic colorectal adenoma,the correlation between CSN6,p-Akt,β-catenin and c-Myc protein expression The correlation analysis showed that the expressions of CSN6 and p-Akt,β-catenin,c-Myc in sporadic colorectal adenoma with dysplasia(r=0.288,P=0.004;r=0.107,P=0.290;r=0.201,P=0.045)and adenocarcinoma group(r=0.245,P=0.014;r=0.325,P=0.001;r=0.200,P=0.044)had a positive relationship.7 In the process of carcinogenesis of sporadic colorectal adenoma,the correlation between FBXW7 and CSN6,β-catenin protein expression analysis The correlation analysis showed that the expressions of FBXW7 and CSN6,β-catenin in sporadic colorectal adenoma with dysplasia(r=-0.366,P=0.000;r=-0.245,P=0.014)and adenocarcinoma group(r=-0.242,P=0.015;r=-0.274,P=0.005)were negatively related.Conclusion:1 The positive expression rate of CSN6 gradually increased in normal colorectal mucosa,adenoma with varying degrees dysplasia and colorectal carcinoma changed from adenoma and CSN6 protein positive expression rate closely related with tumor stage and lymph node metastasis.These results indicate that CSN6 may participate in the progress of sporadic colorectal adenoma canceration and has a function for development of colorectal cancer.2 The positive expression rate of FBXW7 gradually decreased in normal colorectal mucosa,adenoma with varying degrees dysplasia and colorectal carcinoma changed from adenoma,and had a relationship with tumour infiltration depth.These indicate that FBXW7 may participate in the progress of sporadic colorectal adenoma canceration.3 The positive expression rates of p-Akt and Wnt/β-catenin signosome pathway factors such as β-catenin and c-Myc gradually increased in normal colorectal mucosa,adenoma with varying degrees dysplasia and colorectal carcinoma changed from adenoma.Datas show that p-Akt and β-catenin,c-Myc may have a relationship with the development of sporadic colorectal adenoma canceration.4 Results showed that there was a positive correlation between CSN6 and p-Akt which indicates that p-Akt may play a synergistic role with CSN6 in the process of colorectal adenocarcinoma,and promote the development of colorectal adenocarcinoma.5 Results showed that CSN6 had a negative correlation with FBXW while positive correlated with β-catenin and c-Myc in colorectal adenoma and adenocarcinoma,which indicates that CSN6 may play an important role in the carcinogenesis and promoting the development of colorectal adenocarcinoma by negative regulation of FBXW7 and then affect the expression of main factor β-catenin and c-Myc in Wnt signaling pathway.