ZIP11 Regulates Nuclear Zinc Homeostasis in HeLa Cells and Is Required for Proliferation and Establishment of the Carcinogenic Phenotype.
ZIP11 Regulates Nuclear Zinc Homeostasis in HeLa Cells and Is Required for Proliferation and Establishment of the Carcinogenic Phenotype.
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DOI：
10.3389/fcell.2022.895433
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发表时间：
2022
影响因子：
5.5
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锌（Zn）是一种必需的微量元素，在几个生物过程中起着关键作用，包括转录，信号传导和催化。一个亚细胞网络的转运蛋白确保锌的充分分布，以促进稳态。其中有一个家族的进口商，Zrt/Irt样蛋白（ZIP），它由14个成员（ZIP 1-ZIP 14），动员锌从细胞外结构域和细胞器进入胞质溶胶。这些转运蛋白的表达在组织和发育阶段各不相同，它们在不同细胞位置的分布对于确定净细胞锌转运是必不可少的。正常情况下，离子与蛋白质结合或被隔离在细胞器和囊泡中。然而，尽管研究集中在哺乳动物细胞中的Zn内化，但对细胞器内的Zn动员知之甚少，包括在正常和病理条件下的细胞核内。从小鼠分离的胃和结肠组织的分析表明，ZIP 11是唯一定位于哺乳动物细胞核的ZIP转运蛋白，但没有明确的细胞作用归因于这种蛋白质。我们假设ZIP 11对维持哺乳动物细胞核锌稳态是必不可少的。为了测试这一点，我们利用了HeLa细胞，因为在人类中的研究将ZIP 11的表达升高与宫颈癌患者的预后不良相关联。我们在HeLa癌细胞中稳定地敲低ZIP 11，并在体外研究Zn失调的影响。我们的数据显示ZIP 11敲低（KD）由于Zn的核积累而减少HeLa细胞增殖。RNA-seq分析显示，与血管生成、细胞凋亡、mRNA代谢和信号通路相关的基因失调。尽管经历核Zn应激的KD细胞可以通过MTF 1和MT 1激活稳态响应，但RNA-seq分析表明，只有ZIP 14（在质膜和内吞囊泡上表达的导入物）被轻度诱导，这可以解释对细胞外Zn水平升高的敏感性。因此，ZIP 11 KD HeLa细胞具有受损的迁移、侵袭特性和降低的线粒体电位。此外，ZIP 11的KD延迟细胞周期进程，并在HeLa细胞中呈现增强的衰老状态，指出了一种新的机制，即维持核锌稳态对癌症进展至关重要。
Zinc (Zn) is an essential trace element that plays a key role in several biological processes, including transcription, signaling, and catalysis. A subcellular network of transporters ensures adequate distribution of Zn to facilitate homeostasis. Among these are a family of importers, the Zrt/Irt-like proteins (ZIP), which consists of 14 members (ZIP1-ZIP14) that mobilize Zn from the extracellular domain and organelles into the cytosol. Expression of these transporters varies among tissues and during developmental stages, and their distribution at various cellular locations is essential for defining the net cellular Zn transport. Normally, the ion is bound to proteins or sequestered in organelles and vesicles. However, though research has focused on Zn internalization in mammalian cells, little is known about Zn mobilization within organelles, including within the nuclei under both normal and pathological conditions. Analyses from stomach and colon tissues isolated from mouse suggested that ZIP11 is the only ZIP transporter localized to the nucleus of mammalian cells, yet no clear cellular role has been attributed to this protein. We hypothesized that ZIP11 is essential to maintaining nuclear Zn homeostasis in mammalian cells. To test this, we utilized HeLa cells, as research in humans correlated elevated expression of ZIP11 with poor prognosis in cervical cancer patients. We stably knocked down ZIP11 in HeLa cancer cells and investigated the effect of Zn dysregulation in vitro. Our data show that ZIP11 knockdown (KD) reduced HeLa cells proliferation due to nuclear accumulation of Zn. RNA-seq analyses revealed that genes related to angiogenesis, apoptosis, mRNA metabolism, and signaling pathways are dysregulated. Although the KD cells undergoing nuclear Zn stress can activate the homeostasis response by MTF1 and MT1, the RNA-seq analyses showed that only ZIP14 (an importer expressed on the plasma membrane and endocytic vesicles) is mildly induced, which may explain the sensitivity to elevated levels of extracellular Zn. Consequently, ZIP11 KD HeLa cells have impaired migration, invasive properties and decreased mitochondrial potential. Furthermore, KD of ZIP11 delayed cell cycle progression and rendered an enhanced senescent state in HeLa cells, pointing to a novel mechanism whereby maintenance of nuclear Zn homeostasis is essential for cancer progression.