A Relatively Small Gradient of Extracellular pH Directs Migration of MDA-MB-231 Cells In Vitro
A Relatively Small Gradient of Extracellular pH Directs Migration of MDA-MB-231 Cells In Vitro
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DOI：
10.3390/ijms21072565
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发表时间：
2020-04
影响因子：
5.6
通讯作者：
Eiji Takahashi;Daisuke Yamaguchi;Y. Yamaoka
中科院分区：
文献类型：
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作者：
Eiji Takahashi;Daisuke Yamaguchi;Y. Yamaoka
血行性肿瘤转移始于原发肿瘤细胞在局部组织中的侵袭和扩散，导致血管内渗。我们假设肿瘤细胞可能主动向肿瘤内血管迁移，细胞外代谢梯度作为一个指导线索。在这里，我们确定在体外细胞外的pH梯度是否可以作为MDA-MB-231细胞定向迁移的线索。通过伤口愈合测定法在由微流体装置间隙盖玻片（GCG）产生的细胞外pH（~0.2单位/mm）和氧浓度（~ 6%O2/mm）的梯度下测定细胞迁移。在没有GCG的情况下，细胞的迁移在空间上是均匀的;相同数量的细胞从左右边界迁移到矩形伤口空间。相比之下，当GCG产生跨伤口空间的pH/O2梯度时，从具有较高pH/O2值的边界迁移到伤口空间的细胞的数量显著减少，表明细胞在梯度中朝向较高pH/O2的区域优先移动。在细胞外培养基中加入hepes后，细胞外pH梯度和GCG下的定向细胞迁移均消失。我们得出结论，与Na+/H+交换驱动的细胞迁移中发现的pH梯度相比，细胞外介质中相对较小的pH梯度足以引导MDA-MB-231细胞。在代谢梯度的引导下，细胞定向迁移可以有效地提高血管内浸润的可能性，并最终导致血行转移。
Hematogenous tumor metastasis begins with the invasion and spread of primary tumor cells in the local tissue leading to intravasation. We hypothesized that tumor cells might actively migrate toward intratumor vessels with the extracellular metabolic gradient acting as a guiding cue. Here, we determined in vitro whether the extracellular gradient of pH can act as a cue for directional migration in MDA-MB-231 cells. Cell migration was determined by the wound-healing assay under gradients of extracellular pH (~0.2 units/mm) and oxygen concentration (~6% O2/mm) that were produced by a microfluidic device, gap cover glass (GCG). Without GCG, the migration of cells was spatially homogeneous; the same number of cells migrated to the rectangular wound space from the left and right boundaries. In contrast, when GCG generated pH/O2 gradients across the wound space, the number of cells migrating to the wound space from the boundary with higher pH/O2 values was considerably decreased, indicating a preferential movement of cells toward the region of higher pH/O2 in the gradient. The addition of hepes in the extracellular medium abolished both the extracellular pH gradient and the directional cell migration under GCG. We conclude that relatively small gradients of pH in the extracellular medium compared to those found in Na+/H+ exchanger-driven cell migration were sufficient to guide MDA-MB-231 cells. The directional cell migration as guided by the metabolic gradient could effectively elevate the probability of intravasation and, ultimately, hematogenous metastasis.