Department of Surgery, Taipei Medical University, Taipei City, Taiwan.
Ann Surg Oncol. 2010 Dec;17(12):3379-85. doi: 10.1245/s10434-010-1163-4. Epub 2010 Jul 13.
Thrombomodulin (TM) is a key molecule mediating circulation homeostasis through its binding to thrombin. The TM-thrombin complex can activate protein C and thrombin-activatable fibrinolysis inhibitor to form a tight clot. In many cancer tissues, decrease of TM expression may correlate with cancer metastasis. However, the role of TM in hepatocellular carcinoma (HCC) progression is still unclear.
We characterized TM expression in HCC cells (HepJ5 and skHep-1 cells) using real-time polymerase chain reaction (PCR) and Western blotting. We then manipulated TM expression using both TM-specific short hairpin RNA (shRNA) and overexpressing it in HCC cells. Transwell migration assay was performed to monitor the migratory ability of HCC cells under different levels of TM expression.
We found that TM was ectopically highly expressed in skHep-1 at both transcriptional and translational levels. After silencing TM expression in skHep-1 cells, we found that metastatic capability was dramatically increased. Conversely, overexpression of TM in HepJ5 cells decreased metastatic ability. We investigated the possible mechanism and found that decreased TM-mediated enhancement of cell migration was dependent on upregulation of ZEB1, a repressor of E-cadherin.
TM may be a modulator of cancer metastasis in HCC. Downregulation of TM expression may increase ZEB1 and decrease E-cadherin levels.
血栓调节蛋白（TM）是一种通过与凝血酶结合来调节循环平衡的关键分子。TM-凝血酶复合物可以激活蛋白 C 和凝血酶激活的纤溶抑制物，形成紧密的血栓。在许多癌症组织中，TM 表达的减少可能与癌症转移有关。然而，TM 在肝细胞癌（HCC）进展中的作用尚不清楚。
我们使用实时聚合酶链反应（PCR）和 Western blot 分析来表征 HCC 细胞（HepJ5 和 skHep-1 细胞）中的 TM 表达。然后，我们使用 TM 特异性短发夹 RNA（shRNA）和在 HCC 细胞中过表达 TM 来操纵 TM 表达。使用 Transwell 迁移实验来监测不同 TM 表达水平下 HCC 细胞的迁移能力。
我们发现 skHep-1 在转录和翻译水平上都异位高度表达 TM。在 skHep-1 细胞中沉默 TM 表达后，我们发现转移性能力显著增加。相反，在 HepJ5 细胞中过表达 TM 则降低了转移性能力。我们研究了可能的机制，发现 TM 介导的细胞迁移增强的减少依赖于 ZEB1 的上调，ZEB1 是 E-钙黏蛋白的抑制剂。
TM 可能是 HCC 中癌症转移的调节剂。TM 表达的下调可能会增加 ZEB1 并降低 E-钙黏蛋白水平。
