Dissecting the complexity of metastasis with mathematical models and quantitative experiments with in zebrafish

项目摘要 转移--晚期癌症的一个重要特征--通常代表着从可治愈到不可治愈的转变。 疾病。转移级联由癌细胞必须克服的一系列严重障碍组成， 每一次都非常低效和明显的随机；我们目前无法预测是否、何时和 会发生转移的地方。我们建议将生态透镜应用于转移。具体来说，我们将 研究推动循环肿瘤细胞(CTC)群转移潜能增加的过程 通过数学建模和体内定量实验相结合的方法，建立了斑马鱼模型 黑色素瘤。黑色素瘤是最致命的皮肤癌，它显示出与 局部和转移性疾病患者的预后：血液中有CTC簇的患者病情更差 临床预后。尽管它们很重要，但CTC集群形成的机制增加了 转移能力和治疗靶向的潜力仍未得到充分研究--尤其是在黑色素瘤中。我们 利用斑马鱼转移性黑色素瘤模型，包括能够 移植到透明Casper斑马鱼中，这提供了一个强大的系统来定量 从生态学角度探讨CTC团簇转移潜能增加的机制 透视。我们的三个具体目标解决了CTC集群如何与转移健康相关：(目标1)我们 假设种群规模和数量之间的权衡--生态扩散不可或缺的--是 CTC簇的转移形成；我们将用数学模型检验这一假说，以预测 黑色素瘤聚集性的成功如何随大小而变化，我们将用斑马鱼的数据来对抗这些模型 为了量化黑色素瘤CTC簇的转移适应情况；然后我们将引入基因 对假设的星系团内细胞合作机制的扰动，并阐明 形成集群健康格局的基本机制。(目标2)我们假设高内部- 集群多样性促进整体转移适应度，尽管存在一些个体较低的细胞 适合性；我们将通过设计黑色素瘤特定形式的基因簇来检验这一假设 异质性；我们将应用定量统计分析来比较高多样性集群和低多样性集群 移植到斑马鱼体内并评价成分异质性在CTC簇转移中的作用 适应度采用多层次选择理论。(目标3)我们假设微环境梯度 可扩散物质决定了渗出细胞簇的成功；我们将通过以下方式验证这一假设 用偏微分剂模型研究体内、体外和硅胶中的梯度 反应扩散方程。这些目标，再加上在哺乳动物模型中的验证，将产生新的 对CTC集群适合性背后的动力学过程的见解 黑色素瘤和其他癌症的诊断、预后和治疗策略。

Project Summary Metastasis—a defining feature of advanced cancer—often represents a transition from curable to incurable disease. The metastatic cascade consists of a series of severe obstacles that cancer cells must overcome, each one highly inefficient and apparently stochastic; we are presently unable to predict whether, when and where metastases will occur. We propose to apply an ecological lens to metastasis. Specifically, we will investigate the processes driving the increased metastatic potential of circulating tumor cell (CTC) clusters through a combination of mathematical modeling and in vivo quantitative experiments in a zebrafish model of melanoma. Melanoma, the most lethal of skin cancers, shows a particularly stark difference between the outcomes of patients with local versus metastatic disease: Patients with CTC clusters in their blood have worse clinical prognoses. Despite their importance, the mechanisms underlying CTC cluster formation, increased metastatic capacity, and potential for therapeutic targeting remain understudied—particularly in melanoma. We take advantage of the zebrafish model of metastatic melanoma, including the ZMEL1 cell line capable of transplantation into transparent Casper zebrafish, which provides a powerful system to quantitatively investigate the mechanisms behind increased metastatic potential of CTC clusters from an ecological perspective. Our three specific aims address how CTC clusters relate to metastatic fitness: (Aim 1) We hypothesize that the trade-off between group size and number—integral to ecological dispersal—is key in metastasis formation by CTC clusters; we will we will test this hypothesis with mathematical models to predict how the success of melanoma clusters varies with size, and we will confront those models with zebrafish data to quantify the metastatic fitness landscape of melanoma CTC clusters; we will then introduce genetic perturbations on hypothesized mechanisms of cellular cooperation within-clusters and elucidate the mechanisms underlying the shape of the cluster fitness landscape. (Aim 2) We hypothesize that high intra- cluster diversity promotes overall metastatic fitness despite the presence of some cells with lower individual fitness; we will test this hypothesis by engineering clusters with melanoma-specific forms of genetic heterogeneity; we will apply quantitative statistical analyses to compare high- and low-diversity clusters transplanted into zebrafish and evaluate the role of compositional heterogeneity in CTC cluster metastatic fitness using multi-level selection theory. (Aim 3) We hypothesize that microenvironmental gradients of diffusible substances determine the success of clusters of extravasated cells; we will test this hypothesis by investigating gradients in vivo, in vitro and in silico using an agent-based model with partial differential equations of reaction-diffusion. These aims, coupled with validation in mammalian models, will generate new insights into the dynamical processes underlying CTC cluster fitness towards the development of new diagnostic, prognostic and therapeutic strategies in melanoma and other cancers.