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: 10296060
• 负责人: Fotini Gounari
• 金额: $ 64.78万
• 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/10296060
• 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

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 在我们对CRC遗传学和免疫学的理解方面取得了进步，它在很大程度上仍然具有抵抗力 治疗。口腔微生物对大肠的定殖在健康个体中很常见。其中许多 共生对CRC患者具有病理生理影响。但是，它们的作用机理尚不清楚。 我们最近的研究确定帕尔维莫纳斯米尔拉是CRC患者粪便和结肠中最富集的口服细菌 粘膜相对于健康个体。 CRC粪便中的P. Micra和其他口头共生网络 患者排除了保护共生。结肠中一组基因的DNA甲基化的变化 患者的粘膜和血液预测CRC风险。将CRC凳子转移到接受治疗的无菌小鼠 随着AOM导致宿主的DNA甲基化和异常隐窝灶的形成，此后又高于此 通过从健康个体转移微生物群观察到。我们提供了P. Micra可以的初步数据 直接甲基化的人类结肠肿瘤细胞在低氧条件下共同培养时。基于 在这些发现中，我们假设口腔赋与parvimonas举例说明了DNA甲基化 宿主DNA的适应肿瘤并促进CRC。我们将以两个具体的目的解决这个问题。 1。我们将测试 假设在自发CRC的小鼠模型中，P。micra改变了DNA甲基化和表达 影响CRC肿瘤生长和肿瘤助理免疫的宿主基因。容易发生CRC的老鼠会 在有或没有麦粒或嗜酸乳杆菌的情况下，获得健康的人类微生物群以进行比较。减少表示 Bisulfite测序（RRB），Atacseq，RNASEQ，免疫测定和组织病理学将确定如何确定 DNA甲基化影响的变化，（1）CRC肿瘤的生长和侵袭，（2）相关的肿瘤 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 将检验以下假设，即米克拉和细菌社区网络调节肿瘤生长和免疫 通过改变宿主细胞的DNA甲基化的反应。为了测试这一点，我们将（1）确定粪便簇和 CRC患者的组织粘附细菌，并将其与患者结肠的DNA高甲基化相关 跨不同CMS亚类的血液，（2）确定肿瘤和血液的DNA甲基化的改变 突变负荷和免疫反应，（3）区分DNA甲基化的致病与保护模式 在结肠上皮器官中，暴露于P. micra，与嗜酸乳杆菌相比。