Dietary Regulation of Colon Cancer Metastasis

项目总结/摘要 结直肠癌（CRC）是世界上第三大常见癌症，发病率每年都在增加。它是癌症相关死亡的主要原因，主要是由于转移性疾病。CRC主要转移到肝脏，几乎30%的CRC患者发生肝转移，导致严重不良结局和手术外治疗选择有限。我们的首要目标是研究CRC细胞如何转移和适应生理相关的肝脏微环境，基于器官移植的CRC模型，这些模型具有CRC患者中常见的遗传异常。 由于缺乏重现转移性疾病的体内CRC模型，我们对肝脏微环境如何塑造肿瘤细胞反应的理解受到严重阻碍。为了克服目前CRC模型的局限性，我们提出使用利用结肠镜引导的遗传工程类器官原位移植的鼠模型。我们已经确定，这些模型忠实地再现了人类CRC的特征，包括患者中常见的肝转移。使用基于CRISPER/Cas9的编辑，我们将对携带与患者预后不良相关的突变的人类和小鼠CRC类器官进行基因工程改造。我们将使用我们的体内模型从这些类器官中产生亲和非转移性细胞系，然后表征影响疾病进展的肿瘤细胞和微环境中的差异分子变化。我们的初步数据显示，与非转移性类器官相比，促转移性类器官中上皮间质（EMT）转录因子（如Twist 1）的差异调节。我们将描述这些候选EMT转录因子在CRC肝转移中的作用（目的1），并确定区分转移性和非转移性肿瘤细胞的分子机制。目的2研究高脂饮食（HFD）介导的肥胖对结直肠癌肝转移的影响。越来越多的研究表明，HFD和肥胖会影响肠道干细胞的行为和肿瘤的发生，然而，其对疾病进展和转移的影响仍不清楚。使用我们的CRC体内模型，转录组测序和功能验证研究，我们将剖析高脂肪饮食对肿瘤和肝脏微环境，肝转移和总体结果的分子效应。公共/卫生/相关性：这项研究的成功完成将确定启动和维持转移的机制以及HFD诱导的肥胖在这一过程中的作用，揭示CRC生理相关模型的治疗靶向漏洞。

Project Summary/Abstract Colorectal cancer (CRC) is the third most frequent cancer worldwide with increasing incidences every year. It is the leading cause of cancer related mortality, predominantly due to metastatic disease. CRC majorly metastasizes to the liver, and almost 30% of CRC patients develop hepatic metastasis resulting in severely poor outcomes and limited treatment options outside of surgery. Our overarching objective is to examine how CRC cells metastasize and adapt to the liver microenvironment in physiologically relevant, organoid transplantation based CRC models that harbor genetic abnormalities commonly found in CRC patients. Our understanding of how the liver microenvironment shapes the responses of the tumor cells is significantly impeded by a lack of in-vivo CRC models that recapitulate metastatic disease. To overcome the limitations of the current CRC models, we propose the use of a murine model utilizing colonoscopy guided orthotopic transplantation of genetically engineered organoids. We have identified that these models faithfully reproduce the characteristics of human CRC, including liver metastasis commonly observed in patients. Using CRISPER/Cas9 based editing, we will genetically engineer human and murine CRC organoids bearing mutations associated with poor prognosis in patients. We will use our in-vivo model to generate pro and non-metastatic lines from these organoids, followed by characterization of the differential molecular changes in the tumor cells and microenvironment that influence disease progression. Our preliminary data shows the differential regulation of epithelial to mesenchymal (EMT) transcription factors such as Twist1 in pro-metastatic organoids as compared to non-metastatic organoids. We will characterize the role of these candidate EMT transcription factors in CRC liver metastasis (Aim 1), and identify molecular mechanisms that differentiate metastatic from non-metastatic tumor cells. Aim 2 of our proposal will study the effect of high fat diet (HFD)-mediated obesity on liver metastasis in CRC. HFD and obesity have been increasingly shown to influence intestinal stem cell behavior and tumorigenesis, however, its influence on disease progression and metastasis remains unknown. Using our CRC in-vivo models, transcriptomic sequencing and functional validation studies, we will dissect the molecular effects of a high fat diet on tumor and liver microenvironment, liver metastasis and overall outcome. Public/Health/Relevance: Successful completion of this study will identify mechanisms integral to initiate and maintain metastasis as well as the role of HFD-induced obesity in this process, revealing therapeutically targetable vulnerabilities in physiologically relevant models of CRC.