NATURE AND ROLE OF THE MICROBIOME IN MOUSE MODELS OF COLON CANCER

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 与哺乳动物身体相关的微生物种群，被称为微生物区系，可以在人类健康中发挥关键作用。驻留在哺乳动物肠道中的微生物群落是复杂和动态的。这些群落中物种组成或相对物种丰度的变化可以延缓或促进宿主的疾病进展。尽管它的重要性有很多经验证据，但我们现在才开始阐明微生物区系的组成，以及微生物区系中的具体变化如何转化为人类健康的变化。我们的长期目标是确定肠道微生物区系，特别是微生物生物膜，在抑制或增强癌症等疾病方面的作用。这项建议的目的是确定生物膜形成微生物区系在促进结肠癌小鼠模型中的肿瘤形成中的作用。这一建议的中心假设是，在ApcMin小鼠模型中，微生物生物膜水平升高和/或物种组成改变会促进结肠癌的进展。由于APC(结肠腺瘤性息肉病)肿瘤抑制基因突变，ApcMin小鼠结肠癌动物模型有更高的胃肠道肿瘤发展风险。APC基因也是人类散发性结肠肿瘤中最常见的突变基因。我们将确定在ApcMin小鼠结肠癌模型中，生物膜的种类、组成或生物膜形成的水平是否发生了变化。我们的工作假设是，在结肠癌的ApcMin小鼠模型中，生物膜的数量和生物膜种类组成发生了变化。我们将通过确定ApcMin中的生物膜总水平是否与野生型小鼠相比增加来验证这一假设，使用454焦磷酸测序表征我们小鼠模型中的总微生物多样性，并通过测试通过将微生物群从供体小鼠(ApcMin或野生型)的结肠完全转移到受体小鼠的无菌结肠来改变结肠微生物群落结构是否抑制或增强肿瘤的形成。我们还将确定ApcMin或野生型小鼠结肠特有的细菌物种是否直接改变小鼠胃肠道中肿瘤的形成或炎症反应。我们的工作假设是，改变的结肠微生物区系通过刺激结肠上皮中的慢性炎症反应，促进了ApcMin小鼠模型中的癌症进展。我们将通过使用FISH和共聚焦激光扫描显微镜来确定ApcMin特定的微生物物种是否在肿瘤形成部位共定位，通过测试ApcMin小鼠特定的微生物物种是否在小鼠上皮细胞中诱导炎症反应，以及通过识别改变肿瘤形成和/或小鼠上皮炎症的微生物产品来验证这一假设。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The microbial population associated with the mammalian body, termed the microbiota, can play a key role in human health. Microbial communities resident in the mammalian gut are complex and dynamic. Changes in species composition or relative species abundance in these communities can retard or enhance disease progression in the host. Despite much empirical evidence for its importance, we are only now starting to elucidate the composition of the microbiota and how specific alterations in the microbiota translate into changes in human health. Our long-term goal is to characterize the role of the gut microbiota, especially microbial biofilms, in suppressing or enhancing diseases such as cancer. The objective of this proposal is to determine the role of biofilm-forming microbiota in promoting tumor formation in a mouse model of colon cancer. The central hypothesis for this proposal is that elevated levels and/or altered species composition of microbial biofilms enhances colon cancer progression in the ApcMin mouse model. The ApcMin mouse animal model for colon cancer has an increased risk of tumor development in the gastrointestinal tract due to a mutation in the APC (adenomatous polyposis coli) tumor suppressor gene. The APC gene is also the most frequently mutated gene in sporadic colon tumors in humans. We will identify whether the biofilm species composition or level of biofilm formation is changed in the ApcMin mouse model of colon cancer. Our working hypothesis is that the amount of biofilm and the biofilm species composition is altered in the ApcMin mouse model of colon cancer. We will test this hypothesis by determining if total level of biofilm is increased in ApcMin compared to wild-type mice, characterizing total microbial diversity in our mouse model using 454 pyrosequencing, and by testing if tumor formation is suppressed or enhanced by altering colonic microbial community structure through the complete transfer of microbiota from the colon of a donor mouse (ApcMin or wild-type) to the sterilized colon of acceptor mice. We also will determine if bacterial species specific to the ApcMin or wild-type mouse colon directly alter tumor formation or inflammatory response in the mouse GI tract. Our working hypothesis is that altered colon microbiota enhances cancer progression in the ApcMin mouse model by stimulating a chronic inflammatory response in the colonic epithelium. We will test this hypothesis by determining if ApcMin-specific microbial species co-localize at sites of tumor formation using FISH and confocal laser scanning microscopy, by testing if microbial species specific to the ApcMin mouse induce an inflammatory response in mouse epithelial cells, and by identifying microbial products that alter tumor formation and/or inflammation in the mouse epithelium.