Department of Pathology, Tianjin Medical University, Tianjin, China.
Hepatology. 2010 Feb;51(2):545-56. doi: 10.1002/hep.23311.
The up-regulation and nuclear relocation of epithelial-mesenchymal transition (EMT) regulator Twist1 have been implicated in the tumor invasion and metastasis of human hepatocellular carcinoma (HCC). The term vasculogenic mimicry (VM) refers to the unique capability of aggressive tumor cells to mimic the pattern of embryonic vasculogenic networks. However, the relationship between Twist1 and VM formation is not clear. In this study, we explored HCC as a VM and EMT model in order to investigate the role of Twist1 in VM formation. We first examined the expression of Twist1 in human HCC samples and cell lines and found that Twist1 was frequently overexpressed in the nuclear relocation occurring in VM-positive HCCs (13/18 [72%]). Twist1 nuclear expression was likewise significantly associated with VM formation. Clinicopathological analysis revealed that both VM and Twist1 nuclear expressions present shorter survival durations than those without expression. We consistently demonstrated that an overexpression of Twist1 significantly enhanced cell motility, invasiveness, and VM formation in an HepG2 cell. Conversely, a knockdown of Twist1 by the short hairpin RNA approach remarkably reduced Bel7402 cell migration, invasion, and VM formation. Using chromatin immunoprecipitation, we also showed that Twist1 binds to the vascular endothelial (VE)-cadherin promoter and enhances its activity in a transactivation assay.
The results of this study indicate that Twist1 induces HCC cell plasticity in VM cells more through the suppression of E-cadherin expression and the induction of VE-cadherin up-regulation than through the VM pattern in vivo and in a three-dimensional in vitro system. Our findings also demonstrate a novel cogitation in cancer stem-like cell differentiation and that related molecular pathways may be used as novel therapeutic targets for the inhibition of HCC angiogenesis and metastasis.
上皮-间充质转化（EMT）调节剂 Twist1 的上调和核易位与人类肝细胞癌（HCC）的肿瘤侵袭和转移有关。术语血管生成拟态（VM）是指侵袭性肿瘤细胞模拟胚胎血管生成网络模式的独特能力。然而，Twist1 与 VM 形成之间的关系尚不清楚。在这项研究中，我们探索了 HCC 作为 VM 和 EMT 模型，以研究 Twist1 在 VM 形成中的作用。我们首先检查了 Twist1 在人 HCC 样本和细胞系中的表达，发现 Twist1 在 VM 阳性 HCC 中频繁发生核易位（13/18 [72%]）。Twist1 核表达同样与 VM 形成显著相关。临床病理分析显示，VM 和 Twist1 核表达均比无表达的患者生存时间更短。我们一致证明，Twist1 的过表达显着增强了 HepG2 细胞的细胞迁移、侵袭和 VM 形成。相反，短发夹 RNA 方法敲低 Twist1 可显著降低 Bel7402 细胞的迁移、侵袭和 VM 形成。通过染色质免疫沉淀，我们还表明 Twist1 结合血管内皮（VE）-钙粘蛋白启动子并在转激活测定中增强其活性。
本研究结果表明，Twist1 通过抑制 E-钙粘蛋白表达和诱导 VE-钙粘蛋白上调，而不是通过体内和三维体外系统中的 VM 模式，更能诱导 HCC 细胞在 VM 细胞中的可塑性。我们的研究结果还表明了一种新的关于癌症干细胞样细胞分化的思考，并且相关的分子途径可能被用作抑制 HCC 血管生成和转移的新的治疗靶点。
