Pathogenesis of Early Onset Colorectal Cancer: Microbiome Contributions and Mechanisms

摘要 早发性结直肠癌（EO-CRC），定义为年龄小于50岁的个体发病，是一种常见的结直肠癌。 新出现的致命公共卫生威胁。因为结肠里有大量的 微生物生态系统，假设结肠上皮细胞与微生物群的密切联系 可导致人CRC的发生和/或进展。然而，到目前为止，还没有研究调查 已经报道了患有EO-CRC的患者的微生物群/微生物群系。我们小组已经发现结肠粘液- 侵袭性细菌生物膜在50岁以上患者发生的CRC上很常见（称为迟发性CRC，LO- CRC）。我们已经证明，LO-CRC相关的细菌生物膜诱导结肠肿瘤的易感性， 小鼠模型。此外，我们的初步数据现在支持生物膜在EO-CRC上是常见的。在此，我们将 检验EO-CRC个体显示不同的微生物和结肠上皮特征的假设， 年龄匹配的对照组。在我们独特但互补的具体目标中，我们将追踪 在过去35年中CRC上的生物膜形成，测试EO-CRC患者和对照者的抗体应答 疾病和对照组的生物膜和其他微生物，并确定是否微生物暴露诱导的变化 在结肠上皮生物学中降低结肠上皮细胞肿瘤转化的阈值。使用 回顾性和前瞻性人类队列，我们的具体目的是：1）确定纵向关联 通过所有细菌和多探针原位荧光确定的EO-CRC的生物膜结构和组成 杂交（FISH）和16 S rRNA扩增子测序; 2）表征以下的血清抗体的结合： EO-CRC患者对广泛的环境生物体相关抗原（例如，病毒，噬菌体，生物膜 细菌和/或细菌毒素）;和3）通过基于可编程噬菌体展示的谱分析（称为PhIP-Seq）， 通过全基因组定义具有已知生物膜状态的正常EO-CRC上皮的分子特征， 来自EO-CRC的正常人类结肠的甲基化研究和环境应激反应， LO-CRC和健康人。我们的研究结果将提供深入了解微生物协会和结肠上皮细胞 我们预测的细胞机制增强了EO-CRC，最终目标是告知和加速新的 EO-CRC检测、预防和干预策略。

ABSTRACT Early onset colorectal cancer (EO-CRC), defined as disease onset in individuals younger than 50 years, is an emerging, deadly public health threat in the United States. Because the colon contains a densely populated microbial ecosystem, it is hypothesized that the intimate association of colonic epithelial cells with the microbiota can contribute to the initiation and/or progression of human CRC. However, as yet, no studies investigating the microbiota/microbiome of patients with EO-CRC have been reported. Our group has identified that colon mucus- invasive bacterial biofilms are common on CRCs occurring in those older than 50 (termed late onset CRC, LO- CRC). We have demonstrated that LO-CRC-associated bacterial biofilms induce colon tumors in susceptible mouse models. Further, our preliminary data now support that biofilms are common on EO-CRC. Herein, we will test the hypothesis that individuals with EO-CRC display microbial and colonic epithelial signatures that differ from age-matched controls. In our distinct, but complementary, Specific Aims, we will trace the epidemiology of biofilm formation on CRCs for the past 35 years, test the antibody responses of EO-CRC patients and comparator disease and control groups to biofilm and other microbes and determine if microbial exposures induce changes in colon epithelial biology that lower the threshold for colon epithelial cell neoplastic transformation. Using retrospective and prospective human cohorts, our Specific Aims are: 1) to determine the longitudinal association of biofilm structure and composition with EO-CRC defined by all bacterial and multiprobe fluorescent in situ hybridization (FISH) and 16S rRNA amplicon sequencing; 2) to characterize the binding of serum antibodies of EO-CRC patients to a broad array of environmental organism-associated antigens (e.g., viral, phage, biofilm bacterial and/or bacterial toxin) via programmable phage display-based profiling (known as PhIP-Seq); and 3) to define the molecular signatures of normal EO-CRC epithelium with known biofilm status through genome-wide methylation studies and the environmental stress responses of normal human colonoids derived from EO-CRC, LO-CRC and healthy persons. Our results will provide insight into the microbial associations and colon epithelial cell mechanisms that we predict potentiate EO-CRC, with the ultimate goal of informing and accelerating novel strategies for EO-CRC detection, prevention and intervention.