Changes Of Intestinal Flora In Patients Colorectal Adenoma Patients With APC Gene Mutation

Background: Colorectal cancer(CRC)is the third most common cancer in men and the second most common in women,with the third leading cause of death in all cancers.The incidence of colorectal cancer in Asian countries has also risen significantly in the past 20 years' trend.The pathogenesis of colorectal cancer is still not fully understood,but most scholars believe that the result of environmental and genetic interactions.CRC patients 60% ~ 70% of the initial diagnosis is progressing,if the diagnosis before the junction The survival rate of rectal cancer is relatively high,the Patient's 5-year survival rate reached60-95%,but if there is lymph node metastasis,the survival rate dropped sharply to 35%,indicating that early detection and treatment of colorectal cancer prognosis and survival of patients is extremely important.The study found that early diagnosis of CRC prevented about 60% of CRC deaths from occurring and the average five-year survival rate increased from 46% to 73%.However,there are very few early screening methods for clinical use.The false-positive and false-negative rates of noninvasive examination are relatively high.However,colonoscopy is invasive,with some complications and contraindications,and thecosts are high.We know that the vast majority of CRC(95%)are sporadic colorectal cancers,of which more than 80% are transformed by colorectal adenomas.However,no obvious symptoms of colorectal cancer are available for early prevention.Thus,adenoma is an important intermediate colorectal carcinogenesis to adenoma as the starting point to find out its occurrence and development of cancer and risk factors,early diagnosis and prevention of CRC,reduce mortality and improve quality of life appears Very important and urgent?The "adenoma-cancer sequence" model Published by Fearon in Cell in1990 has long been considered as a classic model of CRC.APC is a key gene in colorectal cancer.APC gene mutations can be detected early in cancer,and benign tumors and cancer mutation frequency is similar,so it is generally believed that most of the colon cancer is from the APC gene mutations.APC maintains the stability of the colonic epithelium by decreasing the activity of the Wnt Pathway.When the APC gene is deleted,the activity of the Wnt Pathway increases the proliferation of epithelial cells and finally leads to the formation of adenomas.Nosho et al.Suggest that the formation of colorectal cancer is a complex and diverse process,including the formation of somatic and molecular remodeling,diet,the environment,microorganisms,host immunity and so on.Only 25% of patients with a family history and less than 6% of cancers are significantly associated with the high expression of oncogenes.With the upsurge in human microbiology research in recent years,the human microbiome has been involved in the metabolism of the body and the development of the disease has been It has been demonstrated that experimental studies have shown that microbial fermentation products such as butyrate and microbial activated phytochemicals such as Poly-Phenols have a broad anti-inflammatory andantitumor effect against tumorigenesis signaling pathways such as histone deacetylase Inhibition promotes apoptosis,inhibits proliferation and blocks tumor transformation.Intestinal microbial metabolites and host immune interactions,intestinal microbial and host serum metabolism and other mechanisms are slowly revealed.Currently,gut microbes have made breakthrough progress in cancer treatment.In particular,the combination of gut microbes and immunotherapy has been clinically proven to significantly improve tumor survival in patients with lung cancer and kidney cancer,doubling Increases the disease-free survival of melanoma patients.However,little progress has been made in the field of microbes and tumorigenesis.Although some studies have shown that intestinal microflora has changed in the early stage of cancer,it is obvious that the direct use of differentiated microflora as a predictive model for early screening of colorectal cancer There is not much sensitivity and specificity.It is pointed out that one metabolite can be secreted by many kinds of bacteria,so the single species diversity may not reflect the interaction between intestinal flora and host objectively and comprehensively.At present,with the development of metabolomics,the continuous improvement of various analytical methods and instruments,the detection of the changes of metabolites and cancer and other diseases,the detection of intestinal flora and host serum metabolites has become the gut flora Colorectal cancer have an impact on the production of a good complementary direction.OBJECTIVE: To find out the involvement of gut microbes in the development of colorectal cancer through the combined analysis of intestinal microflora,metabolites,host immune factors and host serum metabolites in normal population,adenomatous polyp patients and early cancer patients The mechanism of the discovery of the secretion of cancer-related metabolitescharacteristic flora,microbial and colorectal cancer mechanism to make a more in-depth exploration.The combination of intestinal flora and metabolites as biomarkers for the prediction and screening of early colorectal cancer.Methods: A total of 46 patients with adenomatous polyps were enrolled in this study.The clinical data of patients,including age,sex,diet,BMI index,CEA,CA199,CA242,polyp size,number,differentiation degree and duration were recorded.patients were divided into mutated group and non-mutated group by region repeat sequencing technology to detect APC gene mutation.Metacomics,metabonomics and serum cytokines were collected from the patients' feces and blood respectively.By multi-omics comparison,find the APC gene mutations associated with intestinal flora and related metabolites.The study communicated well with the patients and the samples collected were reviewed by the ethics committee.Result: 1.Analysis of differences in intestinal flora between the experimental group and the control group found that the abundance of actinobacteria in the phylum level,Bifidoacterium,Streptococcus,Dorea in the genus level and Faecalibacterium Prausnitzii,Roseburia intestinalis,Bifidobacterium Pseudocatenula,Streptococcus salivarius in the Species level was significantly higher than that of the experimental group.And the prediction of differential metabolic pathways between the experimental and control groups showed that the microbial genes in the case group were more annotated to PWY-5104(L-isoleucine biosynthesis),PWY-5676(acetyl-Co A fermented to butyrate),PWY-6588(pyruvate fermentation to acetone),PWY-7197(pyrimidine deoxyribonucleotide phosphorylation),PWY0-166(hyperexcitation of Pyrimidine deoxyribonucleotide de novo biosynthesis),ko00360(Phenylalanine Metabolism),ko00363(bisphenol degradation),ko00472(D-arginine and D-ornithine metabolism).The control microbial genes were more closely annotated to PWY-5384(sucrose-degrading IV)PWY-6507(4-deoxy-L-threose-hex-4-enoPyranuronic acid ester degradation),PWY-7242(Degradation of D-Fructuronate),PWY-724(L-lysine,L-Threonine and Super Pathway II for L-methionine Biosynthesis),RUMP-PWY(Formaldehyde Oxidation).2.Serum metabolomics analysis showed that Synthesis and degradation of ketone bodies,Purine metabolism,Prostate cancer,Biosynthesis of unsaturated fatty acids.Biosynthetic Pathway,Choline metabolism in cancer were significant changed between the exPerimental group and the control group.3.Combination prediction of APC mutations by microbiology and metabolomics showed that the predictive model of the composition of the differential metabolites inosine and hypoxanthine which were significantly elevated in the control group,and Faecalibacterium Prausnitzii which was higher in the experimental group.All have statistical significance,suggesting that there is some kind of antagonism relationship between Faecalibacterium Prausnitzii and inosine and hypoxanthine.ConclusionCompared with the control group,the intestinal flora and serum metabolic profile of the experimental group had significant changed.The four dominant intestinal floras in the control group played an important role in antiinflammatory or immune regulation.Faecalibacterium Prausnitzii is the most important butyrate producing bacteria in human gut.In the serum metabolome level,differential metabolites and significantly altered metabolic pathways revealed that serum profiles of patients in the experimental group were more similar to those of CRC patients,the experimental group expressed high levelsof differential metabolites of inosine and hypoxanthine which enriched in purine metabolic pathways are significantly associated with CRC.The metagenomics and metabolomics combined analysis predicted the APC mutation model and found that the prediction models composed of Faecalibacterium Prausnitzii and inosine and hypoxanthin had significant statistical significance suggesting that there may be some antagonism between the two.Above all,we found that the experimental group had more similar characteristics in the intestinal microflora and serum metabolism profile than control group with the known CRC patients.This conclusion also demonstrated that the APC gene mutation might be one of the heavy starting conditions of the occurrence of CRC from the level of intestinal flora and serum metabolism.And the combined prediction of intestinal flora and serum metabolites also provided experimental ideas and reference for the follow-up studies.