上皮组织对集体细胞迁移引起的机械应力反应强烈，并能够对其进行调节，这对于形态发生、伤口愈合和抑制癌症扩散等生物过程非常重要。当基质基质上的上皮单层主动或被动润湿或去湿时，细胞中会产生压缩、拉伸和剪切应力分量。细胞上的压缩应力增加，通过增加细胞间距离变化的频率，触发细胞内的各种信号传导途径，从而增强细胞间的相互作用。这最终会导致细胞干扰或活细胞被挤出。尽管在这一领域进行了广泛的研究，但仍不清楚细胞如何决定是否堵塞或挤出一个或多个细胞，以及细胞如何减少压缩机械应力。活细胞从单层过度拥挤的区域挤出与细胞排列的拓扑缺陷的存在有关，这是由细胞压缩应力和剪切应力分量之间的相互作用引起的。这些拓扑缺陷刺激细胞重新排列，这是细胞通过强化过度拥挤区域的掠过相互作用来重新建立细胞迁移有序趋势的倾向的一部分。除了单个细胞挤出之外，在单层主动去湿过程中还记录了集体细胞挤出，具体取决于细胞类型、基质刚度和边界条件。细胞干扰已在细胞正面相互作用引起的细胞运动接触抑制的背景下进行了讨论。由于细胞间相互作用在过度拥挤的环境中的细胞重排中发挥着至关重要的作用，因此本次综述重点关注这些相互作用的物理方面，以促进该领域的进一步生物学研究。© 2024。作者。

Epithelial tissues respond strongly to the mechanical stress caused by collective cell migration and are able to regulate it, which is important for biological processes such as morphogenesis, wound healing, and suppression of the spread of cancer. Compressive, tensional, and shear stress components are produced in cells when epithelial monolayers on substrate matrices are actively or passively wetted or de-wetted. Increased compressive stress on cells leads to enhanced cell-cell interactions by increasing the frequency of change the cell-cell distances, triggering various signalling pathways within the cells. This can ultimately lead either to cell jamming or to the extrusion of live cells. Despite extensive research in this field, it remains unclear how cells decide whether to jam, or to extrude a cell or cells, and how cells can reduce the compressive mechanical stress. Live cell extrusion from the overcrowded regions of the monolayers is associated with the presence of topological defects of cell alignment, induced by an interplay between the cell compressive and shear stress components. These topological defects stimulate cell re-alignment, as a part of the cells' tendency to re-establish an ordered trend of cell migration, by intensifying the glancing interactions in overcrowded regions. In addition to individual cell extrusion, collective cell extrusion has also been documented during monolayer active de-wetting, depending on the cell type, matrix stiffness, and boundary conditions. Cell jamming has been discussed in the context of the cells' contact inhibition of locomotion caused by cell head-on interactions. Since cell-cell interactions play a crucial role in cell rearrangement in an overcrowded environment, this review is focused on physical aspects of these interactions in order to stimulate further biological research in the field.© 2024. The Author(s).