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

• 批准号: 10693952
• 负责人: LISA Allyn BOARDMAN
• 金额: $ 59.39万
• 依托单位: MAYO CLINIC ARIZONA
• 依托单位国家: 美国
• 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/10693952
• 关键词: ATAC-seq; Aberrant crypt foci; Ablation; Affect; Age; Antibiotic Therapy; Bacteria; Bacteroides fragilis; Biological; Biological Markers; Blood; Blood Cells; Blood Tests; Carcinogenesis Mechanism; Cells; Chromatin; Coculture Techniques; Colon; Colon Carcinoma; Colonic Neoplasms; Colorectal Cancer; Community Networks; DNA; DNA Methylation; DNMT3a; Data; Development; Disease susceptibility; Epigenetic Process; Epithelial Cells; Epithelium; Exclusion; 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; Invaded; Lactobacillus acidophilus; Large Intestine; 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; Tumor Promotion; Weaning; bacterial community; beta catenin; biobank; bisulfite sequencing; colon bacteria; colon cancer patients; colon carcinogenesis; colorectal cancer risk; colorectal cancer treatment; demethylation; 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

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.

项目摘要 结直肠癌（CRC）是世界范围内最常见的恶性肿瘤之一，并且具有高死亡率。在 尽管我们对CRC的遗传学和免疫学的理解有了进步，但它在很大程度上仍然对 疗法口腔微生物在大肠中的定植在健康个体中是常见的。许多这些 化疗对CRC患者有病理生理学影响。然而，其作用机制尚不清楚。 我们最近的研究确定微小微单胞菌是CRC患者粪便和结肠中最丰富的口腔细菌 相对于健康个体的粘膜。CRC粪便中的P. micra和其他口腔寄生虫网络 患者排除了保护性药物。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CRC风险。将CRC粪便转移至接受治疗的无菌小鼠 AOM导致宿主DNA甲基化和异常隐窝灶的形成， 从健康个体的微生物群转移中观察到。我们提供的初步数据表明，P. micra可以 当在低氧条件下共同培养时，直接甲基化人结肠肿瘤细胞。根据 根据这些发现，我们假设口腔粘膜（以细小单胞菌为例）改变了DNA甲基化 以适应肿瘤并促进CRC。我们将在两个具体目标中解决这个问题。1.我们将测试 在自发性CRC小鼠模型中，微小疟原虫改变了DNA甲基化和 影响CRC肿瘤生长和肿瘤相关免疫的宿主基因。容易发生自发性CRC的小鼠将 获得健康的人类微生物群，有或没有P. micra，或L.嗜酸乳杆菌进行比较。简化代表性 亚硫酸氢盐测序（RRBS）、ATACseq、RNAseq、免疫测定和组织病理学将确定 DNA甲基化的变化影响：（1）CRC肿瘤的生长和侵袭，（2）肿瘤相关的 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 将测试这一假设，即P. micra和细菌群落网络调节肿瘤生长和免疫 通过改变宿主细胞的DNA甲基化来缓解CRC。为了测试这一点，我们将，（1）确定粪便和 结直肠癌患者中的组织粘附细菌，并将其与患者结肠的DNA超甲基化相关， 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，暴露于P. micra而不是L.嗜酸乳杆菌