APC基因突变的结直肠腺瘤患者肠道特征菌群的分析

Colorectal cancer (CRC) results from the progressive accumulation of gene mutations,which induce the initiation and progression of colorectal adenoma-to-carcinoma transition. Adenoma is verified as precancerous lesions in colorectal cancer. APC mutations typically occur in adenoma formation stage, which is an early event in colorectal cancer .Previously we found there were high-risk and high-risk and diversity in colorectal adenoma and cancer patients.However, how they are raised and what factors cooperate with APC mutations to promote the development of adenomas and colorectal cancer are still poorly understood. Due to the large microbial load of the colon, recently there has been heightened interest in the role of gut microbiome in colorectal carcinogenesis.Intestinal microbial might affect the development of colorectal cancer by producing metabolites, carcinogens, and other biologically active substances. The project aimed to analyze The structure and function of microbiome in colorectal adenoma patients with the APC gene mutations,using metagenomic sequencing. Moreover, we will also combine metagenomic sequencing with serum cytokine analysis and feces metabolic profiles to identify the microbes and the microbiota associated with colorectal adenoma patients with APC mutations, and discuss their role in colorectal carcinogenesis. These results might provide new insights for development of potent biomarkers for CRC prevention and therapy, as well as more accurate and personalized diagnosis and treatment strategy.For finding early prevention and treatment of colorectal cancer-specific biomarkers, the development of more accurate and personalized diagnosis and treatment ,it is of great significance.

结直肠癌被认为是由多个基因突变积累使正常粘膜逐步癌变的结果。研究表明，APC基因突变通常发生于腺瘤形成阶段，是结直肠癌发生的早期事件，我们前期发现结直肠腺瘤和结直肠癌患者APC突变存在高发性和多样性特点。但APC基因突变是如何被引发，它又是和哪些因素作用共同促进腺瘤和结直肠癌的发生发展，目前研究甚少。近年发现，肠道菌群可能是影响结直肠癌发生发展的重要环境因素，肠道微生物有可能通过产生代谢物、致癌物及其他生物活性物质影响结直肠癌的发生发展。本项目采用宏基因组测序技术分析APC基因突变结直肠腺瘤患者肠道特征菌群的组成和功能，结合患者肠粘膜定植菌群分析、血清细胞因子谱和粪便代谢组学分析，识别与APC基因突变结直肠腺瘤患者相关标志性菌属，深入探讨肠道菌群协同APC基因突变促进结直肠癌发生的分子机制，对于寻找结直肠癌早期预防和诊治的特异性生物标记物，发展更精确和个性化的诊断和治疗方法，具有重要意义。

本文研究通过区域重测序技术检测腺腺瘤性息肉病人APC基因突变情况，将病人分为突变组与非突变组。采集病人的粪便与血液分别进行宏基因组学、代谢组学检测。通过多组学比较，找到与APC基因突变相关的肠道菌群及其相关的代谢产物，探究肠道微生物参与结直肠癌发生过程。在结果发现APC突变组较之非突变组，肠道菌群及血清代谢轮廓均发生了显著的变化；在血清代谢组学水平，通过对差异代谢产物及显著变化的代谢通路的分析发现，突变组病人的血清代谢轮廓与结直肠癌病人更为相似，其中突变组高表达的差异代谢物肌苷与次黄嘌呤富集的嘌呤代谢通路与结直肠癌显著相关。而且宏基因组学与代谢组学联合分析预测APC突变模型发现，非突变组显著升高的益生菌 Faecalibacterium Prausnitzii与突变组显著升高的差异代谢产物肌苷与次黄嘌呤组成的预测模型均有统计意义，提示 Faecalibacterium Prausnitzii与肌苷，次黄嘌呤之间可能存在的拮抗作用。本研究从肠道菌群与血清代谢层面论证了APC基因突变可能为结直肠癌发生的重要的起始条件之一；同时，肠道菌群与血清代谢物联合预测的结果也为后续的研究提供了实验思路以及参考依据，为微生物与结直肠癌的发生机制做出更深入的探究，并通过肠道菌群与代谢物作为生物标志物联合预测和筛查早期结直肠癌，为结直肠癌的早期诊断和预防、降低死亡率提高生存质量提供理论依据。