Ubiquitin Ligase Cullin 7 Induces Epithelial-Mesenchymal Transition in Human Choriocarcinoma Cells
Ubiquitin Ligase Cullin 7 Induces Epithelial-Mesenchymal Transition in Human Choriocarcinoma Cells
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泛素连接酶 Cullin 7 诱导人绒毛膜癌细胞上皮-间质转化
DOI：
10.1074/jbc.m109.004200
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发表时间：
2010-04-02
影响因子：
4.8
通讯作者：
Wang, Hongmei
中科院分区：
文献类型：
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作者：
Fu, Jiejun;Lv, Xiaoyin;Wang, Hongmei
泛素连接酶 cullin 7 (CUL7) 的种系突变与 3-M 综合征和雅库特身材矮小综合征有关，这两种综合征的特征都是产前和产后生长迟缓。 CUL7 敲除小鼠表现出类似于宫内生长迟缓的胎盘和胚胎缺陷，表明 CUL7 在胎盘形成中的作用。本研究发现 CUL7 在妊娠早期侵入性人胎盘绒毛以及 HTR8/SVneo 和 B6Tert 细胞（源自人妊娠早期滋养层细胞的两种细胞系）中高表达。然而，来自人绒毛膜癌但侵袭能力较弱的足月滋养层细胞或 JEG-3 细胞中的 CUL7 水平较低或无法检测到。 JEG-3细胞中CUL7的强制表达诱导了上皮-间质转化特征性的细胞形态学变化，伴随着上皮标记物E-钙粘蛋白和P-钙粘蛋白的完全丧失以及间质标记物波形蛋白和N-钙粘蛋白的显着升高。表达 CUL7 的 JEG-3 细胞表现出增强的细胞迁移和侵袭。相反，HTR8/SVneo 细胞中的 CUL7 特异性 RNA 干扰导致 E-钙粘蛋白表达增加，细胞迁移和侵袭减少。此外，CUL7 表达通过上调 ZEB1 和 Slug（E-钙粘蛋白的两种转录抑制因子）来下调 E-钙粘蛋白 mRNA 表达。最后，用蛋白酶体抑制剂 MG-132 处理表达 CUL7 的细胞，可部分逆转 CUL7 诱导的 E-钙粘蛋白表达丧失。这些结果表明 CUL7 E3 连接酶是滋养层细胞上皮间质转化和胎盘发育的关键调节因子。
Germ line mutations of the ubiquitin ligase cullin 7 (CUL7) are linked to 3-M syndrome and Yakuts short stature syndrome, both of which are characterized by pre- and post-natal growth retardation. CUL7 knock-out mice show placental and embryonic defects similar to intrauterine growth retardation, suggesting a role of CUL7 in placentation. CUL7 was found in this study to be highly expressed in first trimester invasive human placental villi as well as in HTR8/SVneo and B6Tert cells, two cell lines derived from human first trimester trophoblast cells. However, CUL7 levels in term trophoblast cells or JEG-3 cells, which are derived from human choriocarcinoma but exhibit weak invasion capacity, were low or undetectable. Forced expression of CUL7 in JEG-3 cells induced cell morphological changes characteristic of epithelial-mesenchymal transition, which was accompanied by a complete loss of the epithelial markers E-cadherin and P-cadherin and a significant elevation of mesenchymal markers Vimentin and N-cadherin. JEG-3 cells expressing CUL7 exhibited enhanced cell migration and invasion. Conversely, CUL7-specific RNA interference in HTR8/SVneo cells resulted in increased E-cadherin expression and reduced cell migration and invasion. Furthermore, CUL7 expression downregulated E-cadherin mRNA expression by up-regulating ZEB1 and Slug, two transcriptional repressors of E-cadherin. Finally, CUL7-induced loss of E-cadherin expression was partially reversed by treatment of CUL7-expressing cells with the proteasome inhibitor MG-132. These results suggest that the CUL7 E3 ligase is a key regulator in trophoblast cell epithelial-mesenchymal transition and placental development.