mAb 84, a Cytotoxic Antibody that Kills Undifferentiated Human Embryonic Stem Cells via Oncosis
mAb 84, a Cytotoxic Antibody that Kills Undifferentiated Human Embryonic Stem Cells via Oncosis
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DOI：
10.1002/stem.109
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发表时间：
2009-08-01
期刊：
影响因子：
5.2
通讯作者：
Choo, Andre
中科院分区：
文献类型：
--
作者：
Tan, Heng Liang;Fong, Wey Jia;Choo, Andre
单克隆抗体 mAb 84 可与人胚胎干细胞 (hESC) 上的足萼蛋白样蛋白 1 (PODXL) 结合，此前曾报道在体外和体内试验中可结合并杀死未分化细胞。在这项研究中，我们研究了 mAb 84 诱导 hESC 细胞毒性的机制。细胞凋亡可能不是 mAb 84 介导的细胞死亡的原因，因为与 mAb 84 一起孵育后，在 hESC 中没有观察到 caspase 活性升高或 DNA 碎片增加。相反，细胞凋亡之前发生细胞聚集和细胞膜损伤，导致碘化丙啶的摄取和细胞内钠离子的泄漏。此外，通过扫描电子显微镜检查细胞表面显示，mAb 84处理的细胞的细胞表面上存在孔，而同种型对照中不存在这些孔。这种细胞死亡机制类似于肿瘤病（一种由膜损伤引起的细胞死亡形式）所描述的机制。其他数据表明，mAb 84 与 hESC 的结合在膜损伤之前启动了一系列事件，这与肿瘤作用一致。观察到肌动蛋白相关蛋白（即α-肌动蛋白、桩蛋白和踝蛋白）的降解。这些肌动蛋白相关蛋白的扰动最终导致 PODXL 聚集，从而导致孔的形成。据我们所知，这是第一份以 hESCs 作为模型的胶体细胞死亡的报告。干细胞 2009;27:1792-1801
The monoclonal antibody mAb 84, which binds to podocalyxin-like protein-1 (PODXL) on human embryonic stem cells (hESCs), was previously reported to bind and kill undifferentiated cells in in vitro and in vivo assays. In this study, we investigate the mechanism responsible for mAb 84-induced hESCs cytotoxicity. Apoptosis was likely not the cause of mAb 84-mediated cell death because no elevation of caspase activities or increased DNA fragmentation was observed in hESCs following incubation with mAb 84. Instead, it was preceded by cell aggregation and damage to cell membranes, resulting in the uptake of propidium iodide, and the leakage of intracellular sodium ions. Furthermore, examination of the cell surface by scanning electron microscopy revealed the presence of pores on the cell surface of mAb 84-treated cells, which was absent from the isotype control. This mechanism of cell death resembles that described for oncosis, a form of cell death resulting from membrane damage. Additional data suggest that the binding of mAb 84 to hESCs initiates a sequence of events prior to membrane damage, consistent with oncosis. Degradation of actin-associated proteins, namely, alpha-actinin, paxillin, and talin, was observed. The perturbation of these actin-associated proteins consequently permits the aggregation of PODXL, thus leading to the formation of pores. To our knowledge, this is the first report of oncotic cell death with hESCs as a model. STEM CELLS 2009;27:1792-1801