Role of Gut-Immune Interactions in Aging-Associated Bladder Cancer

摘要 膀胱癌(BCA)主要是一种老年性疾病，具有发展为浸润性疾病的风险。 在生命的第八个十年。老年患者的合并症发生率较高，因此往往不适合 接受标准护理、手术和/或化疗或免疫治疗的候选人。此外，与其他癌症不同的是 例如乳房和结肠，老年人的BCA更具攻击性，与较差的预后相关。老龄化是 也与组织炎症的基线水平升高和肠道的主要差异有关 微生物组。微生物群中与衰老相关的变化和炎症与癌症有关 在多种癌症中，免疫治疗和化疗的发病率和进展以及较差的结果。在……里面 尽管有许多研究描述了这些变化，但机械论研究试图理解 这些变化对BCA的影响相对较少。为了在翻译环境中研究这一现象， 我们让幼鼠(START时为8周)和老年小鼠(START时为78周时)接触模型BCA致癌物质N-丁基- N-(4-羟丁基)亚硝胺(BBN)我们发现，年龄较大的动物的炎症水平高于基线水平 并在BBN治疗16周后发展为更大、更具侵袭性的肿瘤。年龄较大的动物也有更多的炎症 肿瘤，因为我们发现招募的中性粒细胞和巨噬细胞水平较高。先天免疫细胞，特别是 中性粒细胞在结肠癌、肝癌和其他癌症中与促肿瘤表型有关，因此 我们提出炎症改变可能是较大肿瘤的原因之一。随着年龄的增长， 微生物多样性，我们还评估了粪便微生物组的16S测序，以确定这些动物 经历了类似的变化。虽然在研究开始时微生物群相似，但我们发现 随着时间的推移，群体之间的差异，年轻人和老年人之间的ç多样性存在显著差异 患有癌症的动物。这导致了一种假说，即肠道功能障碍促使中性粒细胞募集增加 BCA在老年动物体内的形成。在具体目标1中，我将评估肠道功能障碍和微生物分歧 时间在幼年和年老的动物身上。在具体目标2中，我将使用粪便微生物区系移植来确定 在肿瘤形成过程中，幼年动物和老年动物之间的微生物区系切换可能会影响BCA 肿瘤发生学。在具体目标3中，我将使用药物和遗传抑制中性粒细胞的特定方面 生物学评估中性粒细胞在幼年和老年小鼠BCA发育中的作用。完成这些目标 将提供第一个与衰老相关的BCA增加的小鼠模型。此外，这项研究为 未来的R01研究旨在进行详细的机制研究，以了解中介信号机制 这些观察以及使用联合疗法和免疫疗法作为一种新的治疗方法的研究 BCA。专门用于进行这些研究的时间将作为推动申请者的关键初步数据， 本·伍尔布赖特博士，走向独立的职业生涯。

ABSTRACT Bladder cancer (BCa) is predominantly a disease of aging with the risk of developing invasive disease peaking in the 8th decade of life. Elderly patients have higher rates of co-morbidities and are thus often not suitable candidates for standard of care surgery and/or chemotherapy or immunotherapy. Moreover, unlike other cancers such as breast and colon, BCa in the elderly is more aggressive and associated with poorer outcomes. Aging is also associated with both increased baseline levels of tissue inflammation and major differences in the gut microbiome. Aging-associated changes in the microbiome and inflammation have been linked to cancer incidence and progression, and poorer outcomes with immunotherapy and chemotherapy in multiple cancers. In spite of the numerous studies describing these changes, mechanistic studies attempting to understand how these changes impact BCa are comparatively absent. To investigate this phenomenon in a translational setting, we exposed young (8 weeks at start) and older mice (78 weeks at start) to the model BCa carcinogen N-Butyl- N-(4-hydroxybutyl) nitrosamine (BBN). We found older animals had increased baseline levels of inflammation and developed larger, more aggressive tumors after 16 weeks of BBN. Older animals also had more inflamed tumors as we found higher levels of recruited neutrophils and macrophages. Innate immune cells, particularly neutrophils, have been associated with a pro-tumorigenic phenotype in colon, liver, and other cancers and thus we proposed altered inflammation may be a cause of the larger tumors. As aging results in major changes in microbial diversity, we also evaluated 16S sequencing of the fecal microbiome to determine if these animals underwent similar changes. While the microbiomes were similar at the start of the study, we found major divergences between the groups over time, with significant differences in ß-diversity between young or old animals with cancer. This has led to the hypothesis that gut dysfunction drives neutrophil recruitment to enhance BCa formation in aged animals. In Specific Aim 1, I will assess gut dysfunction and microbial divergence over time in young and old animals. In Specific Aim 2, I will use fecal microbiota transplantation to determine if switching microbiota constituency between young and old animals during tumor formation can affect BCa tumorigenesis. In Specific Aim 3, I will use pharmacological and genetic inhibition of specific aspects of neutrophil biology to evaluate the role of neutrophils in BCa development in young and old mice. Completion of these aims will provide the first murine model for aging related increases in BCa. Moreover, this research sets the stage for future R01 studies aimed at detailed mechanistic studies understanding the signaling mechanisms that mediate these observations as well as studies using combination therapy with immunotherapy as a novel treatment for BCa. Dedicated time to perform these studies will serve as the critical preliminary data to propel the applicant, Dr. Ben Woolbright, towards an independent career.