Study On The Mechanism Of FGF19/FGFR4 And Hyperlipidemia In Promotin The Occurrence And Carcinogenesis Of Colorectal Adenoma

Section ⅠSTUDY ON THE RELATIONSHIP BETWEEN ABNORMAL LIPID METABOLISM AND THE INCIDENCE OF COLORECTAL ADENOMA AND ADENOCARCINOMABackgroundColorectal cancer is one of the most common malignant tumors in the digestive tract.The mortality rate of colorectal cancer ranks third in the world,second only to lung cancer and liver cancer,which seriously threatens the health of the people.Eighty percent of colorectal adenocarcinomas are malignant.Colorectal adenoma is a precancerous lesion of colon cancer.Traditional adenomas include tubular adenoma,tubular villous adenoma,also known as mixed adenoma and villous adenoma.The higher the villous component of adenoma,the higher the tendency of malignancy.Early detection and resection of colorectal adenomas can effectively reduce the incidence and mortality of colorectal cancer.Colonoscopy is the best way to screen adenomas,but it is not widely accepted because of its pain and risk.The occurrence of colorectal adenoma is correlated with age,sex,high-fat diet,smoking,drinking,diabetes and heredity.The activation of oncogenes and the inactivation of tumor suppressor genes are related to the occurrence of colorectal tumors.Oncogenes and tumor suppressor genes also play an important role in different stages of adenoma carcinogenesis.The activation of oncogenes and the inactivation of tumor suppressor genes are related to environmental factors and genetic factors.Some studies believe that abnormal blood lipid metabolism is one of the external factors that lead to the activation of oncogenes and the inactivation of tumor suppressor genes,and abnormal blood lipid metabolism is one of the high risk factors for the occurrence and canceration of colorectal adenomas.Some scholars had analyzed the relationship between blood lipid and colorectal adenoma.There is still some controversy about the relationship between abnormal lipid metabolism and the incidence of colorectal adenoma and adenocarcinoma.Whether abnormal lipid metabolism is the trigger factor of colorectal adenoma canceration is seldom reported.ObjectiveThis study analyzed the differences of sex,age,body mass index(BMI)and plasma levels of TG,TC,LDL-C and HDL-C between adenoma population and non-adenoma population(healthy control group),analyzed the correlation between abnormal lipid metabolism and adenoma and adenocarcinoma,and provided a basis for further study of the mechanism of abnormal lipid metabolism leading to the occurrence,development and canceration of adenoma.To provide evidence for the prevention and treatment of colorectal adenoma and adenocarcinoma.Materials and MethodsA total of 180 patients with adenomas(including tubular adenomas,villous adenomas or mixed tubular-villous adenomas)or adenocarcinomas(including high-grade intraepithelial neoplasia,intramucosal carcinoma and adenocarcinoma)who underwent colonoscopy were randomly selected as the subjects.80 patients with advanced adenocarcinoma were divided into adenocarcinoma group.Eighty healthy people without adenoma who underwent enteroscopy at the same time were selected as control group.General clinical data such as age,sex,weight,height,BMI and so on were collected.Peripheral venous blood was collected fasting one day before colonoscopy for TC,TG,LDL-C and HDL-C laboratory tests and related tests.To analyze the difference of blood lipid level between colorectal adenoma group,adenocarcinoma group and healthy control group,and to further analyze the difference of blood lipid level between tubular adenoma,mixed adenoma(tubular-villous adenoma),villous adenoma and adenocarcinoma group.Statistical analysis was performed by SPSS13.0 software package.The results were expressed by mean+standard deviation(x±s).The differences between groups were analyzed by t-test or chi-square test of two groups of independent sample data.Pearson linear correlation analysis was used for correlation analysis.P<0.05 had statistical significance.Results1.There was no significant difference in BMI of sex,age and body mass index between adenoma group and healthy control group,adenocarcinoma group and healthy control group.2.The average levels of plasma TG,TC and LDL-C in adenoma group were higher than those in healthy control group(P<0.05).3.The mean levels of plasma TG,TC and LDL-C in adenocarcinoma group were higher than those in healthy control group(P<0.001).4.The levels of plasma TC and HDL-C in tubular adenoma,mixed adenoma(tubular-villous adenoma),villous adenoma and adenocarcinoma were significantly different between groups,p=0.001 and p=0.027,respectively.With the increase of the proportion of villus structure in adenoma,plasma TC increased.The level of plasma TC in villous adenoma group was higher than that in tubular adenoma and mixed adenoma group.Conclusions1.The plasma levels of triglyceride(TG),total cholesterol(TC),low density lipoprotein cholesterol(LDL-C)in patients with colorectal adenoma and colorectal adenocarcinoma were higher than those in healthy controls.The difference was statistically significant,indicating that abnormal lipid metabolism was related to the occurrence and development of colorectal adenoma and adenocarcinoma.2.Among the three components of adenoma group,total plasma cholesterol(TC)increased with the increase of the proportion of villous components.The TC level of patients with villous adenoma was the highest,and the possibility of malignant transformation of villous adenoma was the highest in the progress of the three types of adenoma.The TC level of patients with adenocarcinoma was significantly higher than that of other three groups,indicating that total plasma cholesterol was in the process of adenogenesis and development of adenoma,and was similar to that of adenoma.There is a correlation between the increase of villus structural components and the carcinogenesis of adenocarcinoma.By monitoring the changes of blood lipid levels,it may provide a reference for screening colorectal adenomas and adenocarcinomas.Section IISTUDY ON THE CORRELATION BETWEEN FGF19-FGFR4 AND ABNORMAL LIPID METABOLISM PROMOTING OCCURRENCE AND CARCINOGENESIS OF COLORECTAL ADENOMABackgroundColorectal adenoma is a precancerous lesion,showing a tendency to develop into colorectal cancer(CRC).Colorectal cancer is one of the common malignant tumors,which seriously threatens human health.Early colorectal cancer has no specific clinical manifestations,and slight symptoms are easily overlooked.Most of the diagnoses are in the middle and late stages.Eighty percent of colorectal adenomas develop from colorectal adenomas over a period of 7 to 10 years.Colonoscopy is the gold standard for the diagnosis of colon adenoma and colon cancer.Colorectal adenoma and early colon cancer can be resected by minimally invasive endoscopy.Total colonoscopy is the best preventive and therapeutic measure.According to statistics,total colonoscopy and treatment can reduce the incidence of colorectal cancer by 85%.Apart from genetic factors,unhealthy lifestyle is the main cause of colorectal cancer.Obesity and high-fat diet are the high-risk factors.Previous studies have shown that abnormal lipid metabolism can make people susceptible to colorectal adenomas.Some epidemiological and etiological analyses indicate that high calorie diet,hyperlipidemia,abdominal fat,obesity and metabolic syndrome are risk factors for colorectal adenoma.However,the mechanism of the occurrence,progression and canceration of colorectal adenomas caused by abnormal lipid metabolism remains unclear.Fibroblast growth factor 19(FGF19)is a member of the endocrine fibroblast growth factor subfamily.It plays an important role in embryonic development,wound healing,hematopoiesis and angiogenesis.The increased expression of fibroblast growth factor 19 is associated with the pathogenesis of malignant tumors,including leukemia and sarcoma,as well as gastric cancer,pancreatic cancer,bladder cancer,colon cancer,breast cancer and prostate cancer.In addition,fibroblast growth factor 19(FGFR4)is an effective metabolic regulator that affects energy metabolism,bile acid homeostasis and glucose/lipid homeostasis by binding to fibroblast growth factor receptor 4(Fibroblast Growth Factor Receptor,FGFR4).It was found that a neutralizing antibody selectively blocked the binding between fibroblast growth factor 19 and FGFR4,which could inhibit the growth of colon cancer cells.It showed that fibroblast growth factor 19/fibroblast growth factor R4 could not only regulate lipid metabolism,but also regulate the proliferation of cancer cells.Although it is known that fibroblast growth factor 19 is associated with colon cancer and lipid metabolism,there is no study to explore the relationship between fibroblast growth factor 19/fibroblast growth factor 4 and the occurrence,development and canceration of colorectal adenomas,or the effect of fibroblast growth factor 19 on the development of colorectal adenomas and adenocarcinomas.ObjectiveIn the first part of the study,we have confirmed the correlation between dyslipidemia and colorectal adenomas and adenocarcinomas.In this study,we will further explore the relationship between fibroblast growth factor 19 and dyslipidemia,colorectal adenomas and adenocarcinomas,explore the molecular mechanism of dyslipidemia leading to colorectal adenomas,development and carcinogenesis,and evaluate the detection of plasma fibroblast growth factor 19 as a marker.Potential clinical value of screening diagnostic indicators for colorectal adenomas.Materials and MethodsThe subjects were 180 patients with colorectal adenoma,80 patients with colorectal adenocarcinoma and 80 healthy controls.Peripheral blood was collected one day before colonoscopy,plasma and single nucleus cells were separated.Adenoma or adenocarcinoma and 10 cm normal colon mucosa of talus were collected during colonoscopy.Two fresh specimens were frozen and one 10%neutral formalin solution was preserved and sent to the disease.Physical and immunohistochemical examinations.The plasma levels of fibroblast growth factor 19(FGF19)in adenomas,adenocarcinomas and healthy controls were detected by ELISA.The plasma levels of fibroblast growth factor 19 and serum lipid-related indicators were analyzed by combining plasma TG,TC,LDL-C and HDL-C indicators.The expressions of fibroblast growth factor 19 and fibroblast growth factor receptor 4 in peripheral blood mononuclear cells and fresh tissue samples were analyzed by fluorescence quantitative Real time PCR.The expression of fibroblast growth factor 19 and fibroblast growth factor receptor 4 in tissue sections was determined by chemical method.Colorectal cancer cell lines LoVo,COLO 205 and HT29 were cultured in vitro.The cells were co-cultured with 0.1,1,10 or 100 ng/mL gradient concentration of active fibroblast growth factor 19.After 48h,72 h and 96 h,cells were collected.CCK-8 kit was used to detect the cell activity.The expression and quantification of fibroblast growth factor 19 and downstream molecules E-cadherin and cyclinDl in normal colon mucosa,adenoma and colon cancer cells were identified by Western blotting.Statistical analysis was performed by SPSS13.0 software package.The results were expressed by mean ±standard deviation(x±s).The differences between groups were analyzed by t-test or chi-square test of two groups of independent sample data.Pearson linear correlation analysis was used for correlation analysis.P<0.05 had statistical significance.Results1.The levels of plasma fibroblast growth factor 19 in adenoma group(250.7±49.14 pg/mL)and adenocarcinoma group(263.8±64.36 pg/mL)were higher than those in healthy control group(194.0±56.17pg/mL).There was significant difference between adenoma group and healthy control group,adenocarcinoma group and healthy control group.There was no significant difference in the levels of fibroblast growth factor 19 between tubular adenoma,mixed adenoma and villous adenoma.2.Immunohistochemical analysis showed that the positive rates of fibroblast growth factor 19 and fibroblast growth factor receptor 4 were different between the sample groups.The positive rates of fibroblast growth factor 19 and fibroblast growth factor receptor 4 were 74.4%and 81.1%in adenoma group,81.3%and 83.6%in adenocarcinoma group,51.3%and 56.2%in normal control group.There was statistical significance between the two groups.There was no significant difference among histological types of simple adenomas,tubular adenomas,mixed adenomas and villous adenomas.3.Real-time quantitative PCR was used to analyze the transcriptional expression level.The expression levels of FGF19,E-cadherin and cyclinD1 in adenoma tissue and colon cancer cells were higher than those in normal colon mucosa adjacent to adenoma.4.In vitro co-culture of active fibroblast growth factor 19,different concentrations of fibroblast growth factor 19 can stimulate the proliferation of colon cancer cells,compared with the untreated group,there is a statistical difference.5.Western blotting and gray level analysis showed that FGF19,E-cadherin and cyclinD1 were higher in adenoma tissue and colon cancer cells than in normal control group.6.Correlation analysis showed that the expression level of fibroblast growth factor 19 in peripheral blood mononuclear cells was correlated with clinical data of adenoma patients,and was linearly correlated with BMI,TG,TC,LDL-C and HDL-C,with statistical significance.7.Receiver operating characteristic(ROC)was drawn according to the expression level of fibroblast growth factor 19 in plasma and peripheral blood mononuclear cells.The area under the ROC curve of serum fibroblast growth factor 19 was 0.765(95%CI:0.703-0.827;P<0.001)with a cut-off value of 227.5 pg/mL.As a screening index for colorectal adenomas,it had 66.1%sensitivity and 66.2%specificity.If peripheral blood mononuclear cells were extracted to detect the expression of fibroblast growth factor 19,the sensitivity and specificity were 96.1%and 96.5%respectively.It has potential value as a screening index for colorectal adenoma.ConclusionsThere was a positive correlation between the expression level of FGF19 and the level of blood lipid metabolism.FGF19 increased significantly in abnormal blood lipid metabolism.FGF19 and FGFR4 were highly expressed in peripheral blood and tumor tissues of patients with adenoma and adenocarcinoma.Active FGF19 co-cultured with colon cancer cells in vitro can stimulate the proliferation of cancer cells.It suggests that abnormal lipid metabolism may induce the occurrence,development and even canceration of colorectal adenomas by stimulating the abnormal expression of FGF19 and FGFR4,which is the possible mechanism of colorectal adenomas.Detection of plasma FGF19 or peripheral blood mononuclear cell FGF19 expression has potential clinical application value in screening colorectal adenomas,but more clinical experiments are needed to further verify.