Leader cell development and function in Breast Tumor Collective Migration

家长资助计划摘要 在人类乳腺癌和小鼠乳腺癌模型中积累的证据表明，肿瘤 细胞通过基底膜（BM）集体侵入，并继续作为集体群体穿过 富含胶原蛋白的细胞外基质进入淋巴管和血管。而不是单细胞，在循环中 异质性循环肿瘤细胞（CTC）的簇，其还含有肿瘤相关的基质细胞， 作为癌相关成纤维细胞（CAF），占转移的> 90%。 集体运动需要协调的细胞-细胞和细胞-基质相互作用。集体细胞的特征 迁移包括：1）细胞保持物理和功能连接，使得细胞间的完整性 在运动期间保持连接。2)单元的子组通常定义前缘，因此， 集体迁徙的方向。这些细胞被称为“领导者”细胞，在功能上与“追随者”细胞不同 细胞3)集体运动还涉及与辅助基质细胞的密切相互作用， 极性诱导因子和促迁移因子，并通过物理重塑 包围ECM。 已经提出了几种假说来解释集体癌症中的领导细胞的发展。 迁移然而，这些领导细胞如何发展，到达并确定前沿，然后领导有针对性的集体 移民，以及这种现象是否是必要的和足够的影响定向集体移民， 大部分未知。我们已经开发了新的微流控装置，在其中研究的集体迁移， 原发性乳腺肿瘤类器官对多种环境信号的响应 在本提案中，我们建议使用具有其固有细胞的原发性乳腺肿瘤类器官。 异质性，以确定领导细胞如何发展和功能，以响应多种环境 #21453;的信号，引导集体迁徙。为此，我们提出两个具体目标。具体目标1。到 确定原发性乳腺肿瘤类器官内的K14前导细胞如何转移到前沿， 引导集体移民。具体目标2：了解化学机械反馈之间 基于CAF的ECM重塑和基于领导者的入侵。 补充项目摘要 在乳腺肿瘤的侵袭中，成簇的细胞通过周围的基质胶原进入循环。这 这个过程是由领导细胞来调节乳腺肿瘤集体的前面，并“领导”整个 类器官侵入胶原蛋白。补充项目询问是否有一个最佳平衡的细胞 力和胶原密度以及交联。这是一个需要建模预测的多变量问题; 否则，直接进行大量实验来尝试所有可能的方法会困难得多， 细胞类型和胶原组成的组合。这个补充项目研究功能失调的细胞如何- 细胞通讯可以改变在不同硬度和纤维结构的3D环境中的细胞侵入模式。 细胞群体被捕获在基于细胞Potts晶格的建模框架中，胶原蛋白作为3D场 可以通过细胞的力量进化对应于细胞突起的建模参数（由P- 钙粘蛋白和Rac）、细胞-细胞粘附（α-连环蛋白）和细胞收缩性（RhoA）在给定的细胞中是不同的 人口同时，胶原蛋白浓度、降解速率、交联速率和长距离力 传播也是多种多样的。进行模拟，以衡量这些不同的入侵模式 群体根据3D胶原基质的纤维微结构而变化。模型预测 补充项目，特别是关于P-cadherin，Rac，α-catenin和RhoA在集体细胞中的作用 3D入侵，通知其他项目在家长补助。

Project Summary for Parent Grant Accumulated evidence in human breast cancer and mouse models of breast cancer have shown that tumor cells invade collectively through the basement membrane (BM) and continue as collective groups to traverse the collagen-rich ECM to access lymphatic and vascular vessels. Rather than single cells, in the circulation clusters of heterogeneous circulating tumor cells (CTCs), that also contain tumor-associated stromal cells such as cancer associated fibroblasts (CAFs), account for >90% of metastases. To move collectively requires coordinated cell–cell and cell–matrix interactions. Hallmarks of collective cell migration include: 1) Cells remain physically and functionally connected such that the integrity of cell–cell junctions are preserved during movement. 2) A subgroup of cells typically defines the leading edge, and thus, the direction of collective migration. These are known as “leader “cells and differ in function from “follower” cells. 3) Collective movement also involves intimate interaction with accessory stromal cells that release polarity-inducing and pro-migratory factors as well as contribute to path finding by physically remodeling the surrounding ECM. Several hypotheses have been proposed to explain cancer leader cell development during collective migration. Yet how these leader cells develop, arrive and define the front edge, then lead directed collective migration, and whether this phenomenon is necessary and sufficient to effect directed collective migration are largely unknown. We have developed novel microfluidic devices in which to study the collective migration of primary breast tumor organoids in response to multiple environmental signals In the present proposal we propose to use primary breast tumor organoids with their inherent cellular heterogeneity to determine how leader cells develop and function, in response to multiple environmental signals, so as to direct collective migration. To do so we propose two specific aims. Specific Aim 1. To determine how K14 leader cells within primary breast tumor organoids polarize to the leading edge and then function to direct collective migration. Specific Aim 2: To understand chemo-mechanical feedback between CAF-based ECM remodeling and leader-based invasion. Project Summary for Supplement In breast tumor invasion, clustered cells invade through surrounding stromal collagen to enter circulation. This process is regulated by leader cells that come to the front of a breast tumor collective and “lead” the entire organoid to invade collagen. The supplement project asks whether there is an optimal balance of cellular forces and collagen density and crosslinking. This is a multivariate problem that requires modeling predictions; it would otherwise be much more difficult to straightaway perform numerous experiments to try all possible combinations of cell types and collagen compositions. This supplement project studies how dysfunctional cell- cell communication can alter cell invasion modes in 3D environments of varying stiffness and fiber architecture. Cell populations are captured in a cellular Potts lattice-based modeling framework and collagen as a 3D field that can evolve by cellular forces. Modeling parameters corresponding to cell protrusions (regulated by P- cadherin and Rac), cell-cell adhesions (α-catenin), and cellular contractility (RhoA) are varied in a given cell population. In parallel, collagen concentration, degradation rate, crosslinking rate, and long-distance force propagation are also varied. Simulations are performed to measure how invasion modes of these different populations vary according to fiber microstructure of 3D collagen matrices. The modeling predictions from this supplement project, particularly relating to the roles of P-cadherin, Rac, α-catenin and RhoA in collective cell 3D invasion, inform other projects in the parent grant.