Organoid modeling of pre-metastatic niche formation in the liver by primary colorectal tumor secreted factors

转移性疾病仍然是癌症相关死亡的主要原因。在结直肠癌（CRC）中，肝脏是 转移的原发部位;并且，大多数诊断为CRC的患者由于其肝脏转移而死亡。 转移这为研究复杂的转移性肿瘤背后的机制提供了强大的动力。 cascade级联，hopefully希望leading导致to novel新approaches方法for intervention干预.然而，研究生物学机制 导致转移性疾病的原因一直是困难的。最近出现的一个这样的研究目标是 转移前小生境（PMN），其形成远离原发肿瘤，但创造有利的环境 让转移细胞站稳脚跟研究PMN是具有挑战性的，因为在动物模型中几乎不可能 预测什么时候可能发生变化的中性粒细胞，并确定转移后，这是为时已晚。一 临床相关的体外模型，其中转移和导致转移的组织变化可以 观察和操纵将是探索这些机制和识别 如何规避它们。我们的团队现在已经发表了几篇论文，描述了我们的生物工程体外 芯片转移（MOC）平台，由微流体装置和3D细胞外基质（ECM）组成 基于水凝胶肿瘤和组织类器官。我们的目标是使用这些工具来识别和定位早期 由于原发性肿瘤分泌的介质而发生的肝脏PMN的变化，并评估其贡献 CRC转移。我们将通过采用3D肝脏、CRC和骨髓造血来实现这一目标。 祖细胞（BM-HPC）类器官，包含在微流体平台中，以量化肝脏重塑和BM- HPC募集，以及这种重塑如何影响体外转移的可能性和动力学。 我们假设，在我们新的生物工程体外平台中，肿瘤细胞系分泌的介质 不同级别的类器官和患者源性肿瘤类器官（PTO）将诱导相应的光谱 ECM重塑，结构失调和BM-HPC招募，当升高时， 增加了转移。在目标1中，我们将使原代人肝脏和BM-HPC类器官经受CRC 条件培养基，测量肝基质（星状）和免疫（Kupffer）细胞活化，并定量ECM 在组成、结构和机械性能方面的重塑。作为这一目标的一部分，我们将剖析 星状细胞、枯否细胞和BM-HPC对这些变化的相对贡献。在目标2中，我们的MOC 除肝脏和BM-HPC类器官外，器械还将包括肿瘤类器官，我们将评估PMN 在这个动态的多组织平台中形成。将测量从肿瘤到肝类器官的转移。 这将使我们能够将PMN的变化与转移事件联系起来。最终，这些研究将提供 有机会确定肿瘤细胞分泌的介质和PMN的独特特征， 作为未来的目标，早期转移过程之前，成为不可治愈的以及生物标志物， 预测患者的转移。

Metastatic disease remains the primary cause of cancer-related deaths. In colorectal cancer (CRC), the liver is the primary site of metastases; and, the majority of patients diagnosed with CRC die as a result of their hepatic metastases. This provides a powerful motivation to study the mechanisms behind the complicated metastatic cascade, hopefully leading to novel approaches for intervention. However, studying the biological mechanisms that contribute to metastatic disease has been difficult. One such target for research that has arisen recently is the pre-metastatic niche (PMN), which forms distant from the primary tumor, but creates favorable environments for metastasizing cells to take hold. Studying the PMN is challenging, as in animal models it is nearly impossible to predict when changes might happen in the PMN, and after identification of metastases, it is too late. A clinically-relevant in vitro model in which metastasis and the changes to tissues leading up to metastasis can be observed and manipulated would be an invaluable resource for probing these mechanisms and for identifying ways to circumvent them. Our team has now published several papers describing our bioengineered in vitro metastasis-on-a-chip (MOC) platform that is comprised of microfluidic devices and 3D extracellular matrix (ECM) hydrogel-based tumor and tissue organoids. Our objective is to use these tools to identity and pinpoint early changes to the liver PMN that occur because of primary tumor-secreted mediators and assess their contributions to CRC metastasis. We will accomplish this by employing 3D liver, CRC, and bone marrow hematopoietic progenitor cell (BM-HPC) organoids, contained in a microfluidic platform to quantify liver remodeling and BM- HPC recruitment, and in turn, how this remodeling influences the likelihood and kinetics of in vitro metastasis. We hypothesize that within our novel bioengineered in vitro platform, secreted mediators from tumor cell line organoids and patient-derived tumor organoids (PTOs) of varying grade will induce a corresponding spectrum of ECM remodeling, architectural dysregulation, and BM-HPC recruitment, which when heightened, corresponds with increased metastasis. In Aim 1, we will subject primary human liver and BM-HPC organoids to CRC conditioned media, measure hepatic stromal (stellate) and immune (Kupffer) cell activation, and quantify ECM remodeling in terms of composition, architecture, and mechanical properties. As part of this aim, we will dissect out the relative contributions of stellate cells, Kupffer cells, and BM-HPCs to these changes. In Aim 2, our MOC device will include tumor organoids in addition both the liver and BM-HPC organoids and we will assess PMN formation in this dynamic multi-tissue platform. Metastasis from the tumor to liver organoid will be measured. This will enable us to link changes of the PMN to metastatic events. Ultimately, these studies will provide opportunities to identify tumor cell secreted mediators and distinct features of the PMN that could potentially serve as future targets of the early metastatic process prior to becoming incurable as well as biomarkers for prediction of metastasis in patients.