Epigenetic mechanisms of carcinogenesis by Parvimonas micra, an oral cavity commensal turned colon cancer pathogen

口腔共生结肠癌病原体 Parvimonas micra 致癌的表观遗传机制

基本信息

批准号：
10488196
负责人：
Fotini Gounari
金额：
$ 64.53万
依托单位：
MAYO CLINIC ARIZONA
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-13 至 2026-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10488196
关键词：
ATAC-seq Aberrant crypt foci Ablation Address Affect Age Antibiotic Therapy Bacteria Bacteroides fragilis Biological Biological Markers Biological Specimen Banks Blood Blood Cells Blood Tests Carcinogenesis Mechanism Cells Chromatin Colon Colon Carcinoma Colonic Neoplasms Colorectal Cancer Community Networks DNA DNA Methylation DNMT3a Data Development Disease susceptibility Epigenetic Process Epithelial Epithelial Cells Exposure to Feces Fusobacterium nucleatum Gene Expression Genes Genetic Germ-Free Growth Histopathology Human Hypermethylation Hypoxia Immune response Immunity Immunology Immunology procedure Individual Inflammation Intestines Lactobacillus acidophilus Large Intestine Lead Leukocytes Link Malignant Neoplasms Methylation Methyltransferase Gene Microbe Mucous Membrane Mus Mutation Oral Oral cavity Organoids Pathogenicity Patients Pattern Prevention strategy Process Regulator Genes Reporting Risk Factors Signal Pathway Specimen T-Lymphocyte Testing Tissues Tumor Immunity Weaning bacterial community base beta catenin bisulfite sequencing colon bacteria colon cancer patients colon carcinogenesis colorectal cancer risk colorectal cancer treatment epigenome fecal microbiota gut colonization human microbiota humanized mouse improved indexing intestinal epithelium methylome microbial colonization microbial community microbiome microbiota mortality mouse model neoplastic cell oral bacteria oral commensal oral pathogen pathogen risk stratification stem cells suckling therapy resistant transcriptome transcriptome sequencing tumor tumor growth

项目摘要

Project Summary Abstract Colorectal cancer (CRC) is among the most common malignancy worldwide and has a high mortality rate. In spite of advances in our understanding of the genetics and immunology of CRC, it remains largely resistant to therapy. Colonization of the large intestine by oral microbes is common among healthy individuals. Many of these commensals have pathophysiological effects in CRC patients. However, their mechanism of action is unclear. Our recent study identified Parvimonas micra as the most enriched oral bacteria in CRC patient stool and colon mucosa relative to healthy individuals. Networks of P. micra and other oral commensal in the stool of CRC patients excluded protective commensals. Changes in DNA methylation of a set of cardinal genes in the colon mucosa and blood of the patients predicted CRC risk. Transfer of CRC stool to germ free mice that were treated with AOM resulted in DNA methylation of the host and formation of aberrant crypt foci, over and above that observed with transfer of microbiota from healthy individuals. We provided preliminary data that P. micra can directly methylate human colon tumor cells when co-cultured together under hypoxic conditions. On the basis of these findings we hypothesize that oral commensals exemplified by Parvimonas alter DNA methylation of host DNA to adapt to tumors and promote CRC. We will address this in two Specific Aims. 1. We will test the hypothesis that in mouse models of spontaneous CRC, P. micra alters DNA methylation and expression of host genes that affect CRC tumor growth and tumor associate immunity. Mice prone to spontaneous CRC will get healthy human microbiota with or without P. micra, or L. acidophilus for comparison. Reduced representation bisulfite sequencing (RRBS), ATACseq, RNAseq, immune assays, and histopathology will determine how changes in DNA methylation impacts, (1) the growth and invasion of CRC tumors, (2) tumor associated inflammation and immune response, (3) microbial community composition of the tumor mucosa and stool. 2. We will test the hypothesis that P. micra and bacterial community networks regulate tumor growth and immune response in CRC by altering DNA methylation of host cells. To test this we will, (1) Identify clusters of fecal and tissue-adherent bacteria in CRC patients and relate these to the DNA hypermethylation of patient colon and blood across different CMS subclasses, (2) determine how altered DNA methylation of tumor and blood relate to mutation load and immune response, (3) distinguish pathogenic versus protective patterns of DNA methylation in colon epithelial organoids, that result from exposure to P. micra, versus L. acidophilus.

项目概要摘要结直肠癌（CRC）是全球最常见的恶性肿瘤之一，死亡率很高。在尽管我们对结直肠癌遗传学和免疫学的理解取得了进展，但它仍然对结直肠癌具有很大的抵抗力。治疗。口腔微生物在大肠定植在健康个体中很常见。其中许多共生体对 CRC 患者具有病理生理学作用。然而，它们的作用机制尚不清楚。我们最近的研究发现，微小单胞菌是结直肠癌患者粪便和结肠中最丰富的口腔细菌粘膜相对于健康个体。结直肠癌粪便中的 P. micra 和其他口腔共生菌网络患者排除了保护性共生体。结肠中一组主要基因的 DNA 甲基化变化患者的粘膜和血液可预测结直肠癌的风险。将 CRC 粪便转移至接受治疗的无菌小鼠体内与AOM一起导致宿主的DNA甲基化和异常隐窝病灶的形成，除此之外通过从健康个体转移微生物群来观察。我们提供了 P. micra 的初步数据当在缺氧条件下共培养时，直接甲基化人类结肠肿瘤细胞。在此基础上根据这些发现，我们假设以小单胞菌为代表的口腔共生体改变了 DNA 甲基化宿主DNA适应肿瘤并促进CRC。我们将通过两个具体目标来解决这个问题。 1.我们将测试假设在自发性 CRC 小鼠模型中，P. micra 改变 DNA 甲基化和表达影响CRC肿瘤生长和肿瘤相关免疫的宿主基因。易发生自发性 CRC 的小鼠会获取含有或不含 P. micra 或嗜酸乳杆菌的健康人体微生物群以进行比较。代表性减少亚硫酸氢盐测序 (RRBS)、ATACseq、RNAseq、免疫测定和组织病理学将确定如何 DNA 甲基化的变化影响，(1) CRC 肿瘤的生长和侵袭，(2) 肿瘤相关炎症和免疫反应；(3)肿瘤粘膜和粪便的微生物群落组成。 2.我们将检验 P. micra 和细菌群落网络调节肿瘤生长和免疫的假设通过改变宿主细胞的 DNA 甲基化来调节 CRC 的反应。为了测试这一点，我们将：（1）识别粪便簇和 CRC 患者的组织粘附细菌，并将这些细菌与患者结肠和 DNA 的 DNA 高甲基化联系起来跨不同 CMS 亚类的血液，(2) 确定肿瘤和血液的 DNA 甲基化改变如何相关突变负荷和免疫反应，(3) 区分 DNA 甲基化的致病性与保护性模式在结肠上皮类器官中，这是由于暴露于 P. micra 和 L. Acidophilus 而产生的。