Defining the changing microbiome composition and host-microbe mechanistic effects following Apc inactivation during colorectal cancer pathogenesis

项目摘要 在全球范围内，结直肠癌(CRC)是导致男性和女性癌症相关死亡的第二大原因 预计在未来20年内将增长70%。儿童权利公约最早的创始事件之一是 肿瘤抑制基因结肠腺瘤性息肉病(APC)的突变。这种突变启动了渐变 从正常增殖的结肠上皮细胞(CECs)到发育不良的病变，再到最终 肿瘤的形成，称为腺瘤。体细胞APC突变发生在80%的散发性大肠癌中。生长 有证据表明，局部微环境中的因素可以显著影响癌症风险。 开始了。结肠腺瘤环境的一个关键特征是微生物群不平衡。 这些微生物区系组成的破坏，即所谓的生物失调，与许多疾病有关，包括 结肠炎、炎症性肠病和结直肠癌。而生物失调有助于促进腺瘤的进展 和CRC，APC突变是否会触发局部微环境的变化，以促进肿瘤的进展 微生物组的生态失调在很大程度上仍是未知的。使用可诱导的CEC APC截断的小鼠模型， 我们的实验室发现，APC失活和随后的结肠癌发生会导致微生物组失调和 此外，致病菌种的生长与细菌粘膜粘附性的增加有关。这 该提案旨在定义APC后早期微生物组发生变化的时间和机制 失活。我们假设，APC的丢失改变了微环境，导致早期共生丧失。 物种，并为致病生长和致癌提供了栖息地。我们将检验我们的假设 通过以下目标。目标1：确定APC失活对组成、空间/时间的影响 寄主微生物组的动力学和致瘤潜力。利用16S rRNA扩增子测序和 微生物学，我将确定在逐渐的结肠癌发生过程中APC丢失后的早期微生物组变化 并将确定这是否因冒号区域而不同。我会用无菌模型来评估这种变化 微生物群足以诱导结肠肿瘤的发生。目标2：确定APC的机制(S) 灭活会导致微生物群的失调和致病物种的扩张。我会利用 转录组学和代谢组学研究代谢途径和基因调控的变化 与微生物组组成的变化和APC失活的时间有关。这项研究将提供 对APC突变发生的事件以及突变的CEC和 当地的微生物群。

Project Summary Globally, colorectal cancer (CRC) is the second leading cause of cancer-related deaths in men and women and is projected to increase by 70% in the next 20 years. One of the earliest initiating events of CRC is mutation of adenomatous polyposis coli (APC), a tumor suppressor gene. This mutation initiates the gradual progression from normal proliferating colon epithelial cells (CECs) to dysplastic lesions, to the eventual formation of tumors, known as adenomas. Somatic APC mutations occur in >80% of sporadic CRCs. Growing evidence demonstrates that factors within the local microenvironment can significantly influence cancer risk and onset. One key characteristic of the colon adenomatous environment is an imbalanced microbiome. Disruption in the makeup of these microbiota, known as dysbiosis, is related to many diseases, including colitis, inflammatory bowel disease, and CRC. While dysbiosis contributes to promoting adenoma progression and CRC, whether APC mutation triggers changes in the local microenvironment to facilitate tumor progression and microbiome dysbiosis remains largely unknown. Using an inducible murine model of CEC Apc truncation, our lab found that Apc inactivation and subsequent colon tumorigenesis results in microbiome dysbiosis and outgrowth of pathogenic species, further, associated with increased bacterial mucosal adherence. This proposal aims to define the timing and mechanisms by which the early microbiome changes following Apc inactivation. We hypothesize that Apc loss alters the microenvironment to cause early loss of commensal species and provides a habitat for pathogenic outgrowth and pro-carcinogenesis. We will test our hypothesis through the following aims. Aim 1: Defining the effects of Apc inactivation on the composition, spatial/temporal dynamics, and tumorigenic potential of the host microbiome. Using 16S rRNA amplicon sequencing and microbiology, I will identify early microbiome changes following Apc loss during gradual colon tumorigenesis and will determine if this differs by colon region. I will use germ-free models to evaluate if the changing microbiome is sufficient to induce colon tumorigenesis. Aim 2: Identifying the mechanism(s) by which Apc inactivation contributes to microbiome dysbiosis and the expansion of pathogenic species. I will utilize transcriptomics and metabolomics to examine changes in metabolic pathways and gene regulation in association with changes in microbiome composition and timing of Apc inactivation. This research will provide novel insights into the events occurring upon Apc mutation and the crosstalk between mutated CECs and the local microbiome.