Department of Biomedical Engineering, Yale University, New Haven, CT 06511.
Systems Biology Institute, Yale University, West Haven, CT 06516.
Mol Biol Cell. 2023 Nov 1;34(12):ar122. doi: 10.1091/mbc.E23-03-0103. Epub 2023 Sep 6.
The invasive potential of glioblastoma cells is attributed to large changes in pressure and volume, driven by diverse elements, including the cytoskeleton and ion cotransporters. However, how the cell actuates changes in pressure and volume in confinement, and how these changes contribute to invasive motion is unclear. Here, we inhibited SPAK activity, with known impacts on the cytoskeleton and cotransporter activity and explored its role on the migration of glioblastoma cells in confining microchannels to model invasive spread through brain tissue. First, we found that confinement altered cell shape, inducing a transition in morphology that resembled droplet interactions with a capillary vessel, from "wetting" (more adherent) at low confinement, to "nonwetting" (less adherent) at high confinement. This transition was marked by a change from negative to positive pressure by the cells to the confining walls, and an increase in migration speed. Second, we found that the SPAK pathway impacted the migration speed in different ways dependent upon the extent of wetting. For nonwetting cells, SPAK inhibition increased cell-surface tension and cotransporter activity. By contrast, for wetting cells, it also reduced myosin II and YAP phosphorylation. In both cases, membrane-to-cortex attachment is dramatically reduced. Thus, our results suggest that SPAK inhibition differentially coordinates cotransporter and cytoskeleton-induced forces, to impact glioblastoma migration depending on the extent of confinement.
成胶质细胞瘤细胞的侵袭潜力归因于由多种元素（包括细胞骨架和离子共转运蛋白）驱动的压力和体积的巨大变化。然而，细胞在受限环境中如何调节压力和体积的变化，以及这些变化如何促进侵袭运动尚不清楚。在这里，我们抑制了 SPAK 的活性，已知 SPAK 活性对细胞骨架和共转运蛋白活性有影响，并探索了 SPAK 在模拟通过脑组织侵袭性扩散的限制微通道中对成胶质细胞瘤细胞迁移的作用。首先，我们发现限制改变了细胞形状，诱导形态发生转变，类似于液滴与毛细血管的相互作用，从低限制时的“润湿”（更具附着力）转变为高限制时的“非润湿”（附着力降低）。这种转变的标志是细胞对限制壁的压力从负变为正，迁移速度也增加。其次，我们发现 SPAK 通路以不同的方式影响迁移速度，这取决于润湿的程度。对于非润湿细胞，SPAK 抑制增加了细胞表面张力和共转运蛋白活性。相比之下，对于润湿细胞，它还降低了肌球蛋白 II 和 YAP 的磷酸化。在这两种情况下，膜与皮质的附着都大大减少。因此，我们的结果表明，SPAK 抑制通过协调共转运蛋白和细胞骨架诱导的力，根据限制的程度，对成胶质细胞瘤的迁移产生不同的影响。
