Leader cell development and function in Breast Tumor Collective Migration

在人类乳腺癌和乳腺癌小鼠模型中积累的证据表明 肿瘤细胞通过基底膜(BM)集体侵袭，并作为集体继续存在 穿过富含胶原的细胞外基质，进入淋巴管和血管。而不是单个单元格，在 异质循环肿瘤细胞(CTCs)的循环簇，也包含肿瘤相关细胞 间质细胞，如癌症相关成纤维细胞(CAF)，占转移的90%。 集体移动需要协调的细胞-细胞和细胞-基质相互作用。的特点 集体细胞迁移包括：1)细胞保持物理和功能连接，以使完整性 的细胞-细胞连接在移动过程中被保存。2)单元格的子组通常定义前导 因此，这就是集体移徙的方向。这些细胞被称为“先导”细胞，它们的功能不同 来自“追随者”细胞。3)集体运动还涉及到与附属基质细胞的亲密相互作用 它释放了极性诱导和亲迁移因子，并有助于通过物理方式找到路径 重塑周围的ECM。 已经提出了几种假说来解释癌症先导细胞在集体过程中的发展 迁移。然而，这些领导细胞是如何发展、到达和定义前沿的，然后领导着集体 移徙，以及这一现象是否是实现定向集体移徙的必要和充分条件 在很大程度上是未知的。我们已经开发了用于研究集体的新型微流控装置 原发乳腺肿瘤有机物对多种环境信号的迁移 在目前的提案中，我们建议使用具有固有细胞的原发乳腺肿瘤器官 异质性，以确定领导细胞如何发展和功能，以响应多种环境 发出信号，以指导集体移徙。为此，我们提出了两个具体目标。具体目标1.至 确定原发乳腺肿瘤细胞器内的K14先导细胞如何极化到前沿，然后 具有指导集体迁徙的功能。具体目标2：了解化学-机械反馈 基于CAF的ECM重塑和基于领导者的入侵。

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.