Single-cell tracking demonstrates copper chaperone Atox1 to be required for breast cancer cell migration
Single-cell tracking demonstrates copper chaperone Atox1 to be required for breast cancer cell migration
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DOI：
10.1073/pnas.1910722117
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发表时间：
2020-01-28
影响因子：
11.1
通讯作者：
Wittung-Stafshede, Pernilla
中科院分区：
文献类型：
--
作者：
Blockhuys, Stephanie;Zhang, Xiaolu;Wittung-Stafshede, Pernilla
铜离子是癌症的几个特征所必需的。然而，涉及的途径、机制和铜结合蛋白大多是未知的。我们最近发现在乳腺癌中上调的细胞质抗氧化剂1铜伴侣蛋白(Atox1)定位于侵袭性乳腺癌细胞的膜脂边缘。为了揭示在细胞迁移中可能扮演的角色的分子洞察力，我们在这里通过视频显微镜研究了乳腺癌细胞(MDA-MB-231)作为Atox1的功能的迁移。在9小时的时间序列中对数百个单个细胞(根据情况)的跟踪显示，当Atox1在细胞中沉默时，细胞的迁移速度和方向性显著降低。由于沉默铜转运体ATP7A也减少了细胞迁移，这些蛋白质似乎在同一条途径上，这表明它们众所周知的铜转运体活动参与其中。细胞内邻近连接分析表明，Atox1、ATP7A和赖氨酰氧化酶原(LOX；通过ATP7A载铜)都非常接近，并且在细胞内Atox1沉默后LOX活性降低。由于LOX是癌细胞迁移的既定参与者，我们的结果表明，Atox1通过ATP7A-LOX轴上的铜协调运输来介导乳腺癌细胞的迁移。由于单个细胞的迁移是乳腺癌转移的早期步骤，肿瘤细胞中的Atox1水平可能是转移潜力的预测指标，并可作为铜耗竭治疗的生物标志物。
Copper ions are needed for several hallmarks of cancer. However, the involved pathways, mechanisms, and copper-binding proteins are mostly unknown. We recently found that cytoplasmic Antioxidant 1 copper chaperone (Atox1), which is up-regulated in breast cancer, is localized at the lamellipodia edges of aggressive breast cancer cells. To reveal molecular insights into a putative role in cell migration, we here investigated breast cancer cell (MDA-MB-231) migration by video microscopy as a function of Atox1. Tracking of hundreds of individual cells (per condition) over a 9-h time series revealed that cell migration velocity and directionality are significantly reduced upon Atox1 silencing in the cells. Because silencing of the copper transporter ATP7A also reduced cell migration, these proteins appear to be on the same pathway, suggesting that their well-known copper transport activity is involved. In-cell proximity ligation assays demonstrated that Atox1, ATP7A, and the proenzyme of lysyl oxidase (LOX; copper-loaded via ATP7A) are all in close proximity and that LOX activity is reduced upon Atox1 silencing in the cells. Since LOX is an established player in cancer cell migration, our results imply that Atox1 mediates breast cancer cell migration via coordinated copper transport in the ATP7A-LOX axis. Because individual cell migration is an early step in breast cancer metastasis, Atox1 levels in tumor cells may be a predictive measure of metastasis potential and serve as a biomarker for copper depletion therapy.