Dietary Regulation of Colon Cancer Metastasis

项目摘要/摘要 结直肠癌(CRC)是全球第三大常见癌症，发病率呈逐年上升趋势。它是癌症相关死亡的主要原因，主要是由于转移性疾病。结直肠癌主要转移到肝脏，几乎30%的结直肠癌患者发生肝转移，导致严重的不良预后和有限的手术外治疗选择。我们的主要目标是研究在生理相关的、基于器官移植的CRC模型中，CRC细胞是如何转移和适应肝脏微环境的，这些模型中含有在CRC患者中常见的遗传异常。 我们对肝脏微环境如何塑造肿瘤细胞的反应的理解因缺乏体内CRC模型而严重受阻，这些模型概括了转移性疾病。为了克服目前结直肠癌模型的局限性，我们建议使用结肠镜引导下的基因工程有机体原位移植的小鼠模型。我们已经确认，这些模型忠实地再现了人类结直肠癌的特征，包括在患者中经常观察到的肝转移。使用基于CRISPER/Cas9的编辑，我们将对携带突变的人类和小鼠CRC有机物进行基因工程，这些突变与患者的预后不良有关。我们将使用我们的体内模型从这些有机化合物中产生促进和非转移系，然后描述影响疾病进展的肿瘤细胞和微环境中的不同分子变化。我们的初步数据显示，与非转移性器官相比，上皮间充质(EMT)转录因子如Twist1在转移性器官中的调控存在差异。我们将表征这些候选EMT转录因子在结直肠癌肝转移中的作用(目标1)，并识别区分转移和非转移肿瘤细胞的分子机制。我们建议的目的2将研究高脂饮食(HFD)介导的肥胖对结直肠癌肝转移的影响。HFD和肥胖已经越来越多地被证明影响肠道干细胞的行为和肿瘤的发生，然而，它对疾病进展和转移的影响尚不清楚。利用我们的结直肠癌体内模型、转录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、肝脏转移和总体预后的分子影响。公共/健康/相关性：这项研究的成功完成将确定启动和维持转移的不可或缺的机制，以及HFD诱导的肥胖在这一过程中的作用，揭示生理相关的结直肠癌模型中具有治疗靶向性的脆弱性。

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.