Secreted Frizzled Related Protein 2 Modulates Epithelial–Mesenchymal Transition and Stemness via Wnt/β-Catenin Signaling in Choriocarcinoma
Secreted Frizzled Related Protein 2 Modulates Epithelial–Mesenchymal Transition and Stemness via Wnt/β-Catenin Signaling in Choriocarcinoma
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DOI：
10.1159/000494862
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发表时间：
2018-11
影响因子：
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通讯作者：
Xianling Zeng;Yafei Zhang;Huiqiu Xu;Taohong Zhang;Yan Xue;R. An
中科院分区：
文献类型：
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作者：
Xianling Zeng;Yafei Zhang;Huiqiu Xu;Taohong Zhang;Yan Xue;R. An
背景/目标：绒毛膜癌（CC）是一种高度侵袭性的妊娠滋养细胞肿瘤，然而，其侵袭和转移的分子机制仍然知之甚少。人分泌型卷曲相关蛋白2（SFRP 2）在不同的肿瘤中可作为肿瘤促进剂或抑制剂发挥作用，但其在CC侵袭和转移中的作用尚不清楚。本研究旨在探讨SFRP 2在CC中的作用及其机制。方法：采用免疫组织化学方法检测SFRP 2在大肠癌组织中的表达。采用亚硫酸氢盐测序PCR（BSP）、Western blotting和定量RT-PCR检测SFRP 2在CC细胞系、JEG-3和JEG-3中的甲基化水平和表达。通过一系列体外功能研究来检测通过5-Aza-2 '-脱氧胞苷（5-Aza）使SFRP 2的启动子去甲基化而增加表达的SFRP 2的生物学作用。此外，采用慢病毒转染技术，在体外和体内研究SFRP 2基因敲减在JEG-3和JAR细胞中的生物学作用。并对其下游信号通路进行了研究。结果如下：SFRP 2在CC组织中表达下调，其表达与JEG-3和TNM细胞中启动子甲基化频率呈负相关。通过其启动子去甲基化增加SFRP 2抑制细胞迁移，侵袭和集落形成在JEG-3和JEG细胞，而减少SFRP 2逆转上皮间质转化（EMT）过程和干细胞在JEG-3和JEG细胞在体外和体内。从机制上讲，SFRP 2通过经典Wnt/β-连环蛋白信号传导调节CC细胞系的EMT和干性，通过使用Wnt激活剂和抑制剂进行验证。结论：目前的研究表明，下调的SFRP 2通过激活Wnt/β-catenin信号转导在体外和体内调节癌症干细胞性和EMT表型，在CC中具有有效的促肿瘤作用。
Background/Aims: Choriocarcinoma (CC) is a highly aggressive gestational trophoblastic neoplasia; however, the underlying molecular mechanisms of its invasiveness and metastasis remain poorly understood. Human secreted frizzled-related protein 2 (SFRP2) could function as a tumor promoter or suppressor in different tumors, yet the role it plays in CC’s invasion and metastasis is thoroughly unclear. The current study was aimed to explore the function and underlying mechanism of SFRP2 in CC. Methods: The expression of SFRP2 in CC tissues was examined via immunohistochemistry. The methylation level and expression of SFRP2 in CC cell lines, JEG-3 and JAR were examined via bisulfite sequencing PCR (BSP), western blotting and quantitative RT-PCR. The biological role of increasing expressed SFRP2 through its promoter demethylation with 5-Aza-2’-deoxycytidine (5-Aza) was examined by a series of in vitro functional studies. Furthermore, lentivirus transfection technology was adopted to investigate the biological roles of SFRP2 knockdown in JEG-3 and JAR cells in vitro and in vivo. Moreover, its downstream signaling pathway was investigated. Results: SFRP2 was downregulated in CC tissues, and its expression was inversely related to its promoter hypermethylation frequency in JEG-3 and JAR cells. Increased SFRP2 through its promoter demethylation inhibited cell migration, invasion and colony formation in JEG-3 and JAR cells, whereas decreased SFRP2 reversed the epithelial-mesenchymal transition (EMT) process and stemness in JEG-3 and JAR cells both in vitro and vivo. Mechanistically, SFRP2 regulated the EMT and stemness of CC cell lines via canonical Wnt/β-catenin signaling, validated by the usage of a Wnt activator and inhibitor. Conclusion: The current study indicates that downregulated SFRP2 has potent tumor-promotive effects in CC through the modulation of cancer stemness and the EMT phenotype via activation of Wnt/β-catenin signaling in vitro and in vivo.