Biomechanical regulation of cell extrusion and migration during metastasis

转移过程中细胞挤出和迁移的生物力学调节

• 批准号: 2451224
• 金额: --
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2451224
• 关键词: Biomechanical; regulation; cell; extrusion; migration

Most adult tumours are comprised of tightly bound epithelial cells organised into continuous sheets. The extrusion of cancer cells from these sheets is an important initial step in metastasis. It was previous believed that tumour cell extrusion is driven by epithelialmesenchymal transition (EMT) whereby cancer cells lose epithelial phenotypes and adhesions to neighbouring cells. However, recent evidence has suggested a more complex behaviour, where different cancer subtypes perform varying degrees of EMT and in certain cases, EMT may not be required at all. Furthermore, tumour cells often disseminate via collective migration where group of cells migrate together with intact adhesions among neighbours. Cell collectives can then enter the bloodstream as circulating tumour cell clusters, which are "the most likely harbingers of metastases" due to their 50-100X greater metastatic potential than equal numbers of individual circulating cells.We currently do not fully understand how cell-cell and cell-ECM adhesions, intrinsic forces (cortical tension) or extrinsic biomechanical forces (extracellular environment) contribute to the a) extrusion of cells from epithelial sheets and b) individual vs. collective migration. Our lack of physiologically-relevant models capable of isolating these variables severely hampers our ability to study their contributions and interactions during tumour cell dissemination. In this work, we aim to use novel microfabricated devices to explore how cell-cell contacts, cell-cell interfacial tension and "squeeze" forces applied by neighbouring tissues drive tumour cell extrusion and detachment. Confinement of doublets into geometric shapes (2D micropatterned substrates) has a dramatic influence on intercellular boundaries, cortical tension and cell motility. Depending on the tensional level, cells displayed undulated, weak junctions and migrate faster (circular shapes) or strong junctions and less motility (triangular shapes), resembling healthy epithelial tissues. This indicates an essential role of cell cortex stiffness and intracellular mechanics to influence the ability to stick together or to migrate faster, and that these can be controlled via geometric confinement.We hypothesize that (i) the lower cortical tension seen in tumour cells increases tumour cell dissemination by weakening cohesion among neighbours and (ii) biomechanical forces and the balance between cell-cell & cell-ECM adhesions control the detachment and dissemination of cancer cells as individual vs. clusters from benign tumours.As a model of carcinoma development, we will use a panel of cells: primary keratinocytes, immortalized keratinocytes, and two sets of primary tumour and metastatic head and neck carcinoma cells from patients (available in the Braga lab; keratinocyte-derived tumours). We will design novel platforms to provide high controllability of mechanical stress. We aim to: Design next generation 3D-microwell arrays and microchannels to evaluate the influence of cell geometry and external mechanical forces on adhesive properties and migration; Define the response of cells at various stages of transformation to variations in intrinsic cortical tension and external mechanical forces; Compare the oncogenic signalling in the various geometric challenges (3D cellular microwell) and cell detachment/motility as cohorts (microchannels).Outcomes: This project will accelerate our understanding of the factors that drive tumour cell extrusion and motility, enabling us to devise novel anti-metastatic strategies to inhibit tumour cell invasion. The project will generate comprehensive knowledge of mechanical force regulation of metastasis, how different states of tumour progression respond to tensional challenges, molecular regulators and screening platforms to interfere with the process.

大多数成人肿瘤由紧密结合成连续片状的上皮细胞组成。从这些薄片中挤压出癌细胞是转移的重要初始步骤。以前认为，肿瘤细胞挤压是由上皮间充质转化（EMT）驱动的，即癌细胞失去上皮表型和对邻近细胞的粘附。然而，最近的证据表明了一种更复杂的行为，不同的癌症亚型执行不同程度的EMT，在某些情况下，可能根本不需要EMT。此外，肿瘤细胞通常通过集体迁移传播，在这种情况下，细胞群会在邻居之间完整地粘附在一起迁移。细胞群可以作为循环肿瘤细胞簇进入血液，这是“最有可能的转移前兆”，因为它们的转移潜力比相同数量的单个循环细胞高50-100倍。我们目前还不完全了解细胞-细胞和细胞- ecm粘附、内在力（皮质张力）或外在生物力学力（细胞外环境）是如何导致a)细胞从上皮片中挤压出来的，b)个体与集体迁移的。我们缺乏能够分离这些变量的生理相关模型，严重阻碍了我们研究它们在肿瘤细胞传播过程中的贡献和相互作用的能力。在这项工作中，我们的目标是使用新的微加工设备来探索细胞-细胞接触，细胞-细胞界面张力和邻近组织施加的“挤压”力如何驱动肿瘤细胞挤压和脱离。限制成几何形状的双重（二维微图案底物）对细胞间边界，皮质张力和细胞运动有显著的影响。根据不同的张力水平，细胞表现为波动，弱连接和移动更快（圆形）或强连接和运动较少（三角形），类似于健康的上皮组织。这表明细胞皮质硬度和细胞内力学在影响粘在一起或更快迁移的能力方面起着重要作用，这些可以通过几何限制来控制。我们假设(i)肿瘤细胞中较低的皮质张力通过削弱邻近细胞之间的内聚而增加了肿瘤细胞的播散；（ii）细胞-细胞和细胞- ecm粘附之间的生物力学力和平衡控制了良性肿瘤中单个或集群癌细胞的分离和播散。作为癌症发展的模型，我们将使用一组细胞：原发性角化细胞，永生化角化细胞，以及两组来自患者的原发性肿瘤和转移性头颈部癌细胞（可在Braga实验室获得；角化细胞来源的肿瘤）。我们将设计新颖的平台，以提供高可控性的机械应力。我们的目标是：设计下一代3d微孔阵列和微通道，以评估细胞几何形状和外部机械力对粘合剂性能和迁移的影响；定义细胞在转化的不同阶段对内在皮层张力和外部机械力变化的反应；比较不同几何挑战（3D细胞微孔）和细胞脱离/运动队列（微通道）中的致癌信号。结果：该项目将加速我们对驱动肿瘤细胞挤压和运动的因素的理解，使我们能够设计出新的抗转移策略来抑制肿瘤细胞的侵袭。该项目将全面了解转移的机械力调节，肿瘤进展的不同状态如何应对张力挑战，分子调节剂和干扰该过程的筛选平台。