Liver Cancer Institute, Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032, China.
Int J Biochem Cell Biol. 2012 Dec;44(12):2308-20. doi: 10.1016/j.biocel.2012.09.012. Epub 2012 Sep 23.
Hepatocellular carcinoma (HCC) is the third most common cause of cancer mortality. Metastasis is the major concern that causes death in HCC. The goal of this study was to identify tumor-derived proteins in serum during HCC metastasis using an orthotopic xenograft tumor model and explore the role of key protein in HCC metastasis. Serum samples collected from HCCLM3-R metastatic HCC tumor model at specific stages of metastasis (1 wk, 3 wks and 6 wks) were subjected to iTRAQ labeling followed by 2DLC-ESI-MS/MS analysis. Twenty tumor-derived proteins were identified through human specific peptides. Secretory clusterin (sCLU), which was significantly upregulated during cancer progression and metastasis, was chosen for further study. The expression of sCLU was significantly higher in metastatic HCC cell lines and samples from metastatic HCC patients. ShRNA-mediated down-regulation of sCLU resulted in a reduced migratory capacity in HCC cell lines, as well as a reduction in pulmonary metastasis in vivo. Overexpression of sCLU in HepG2 cell line showed increased cell migratory ability. Further study found that sCLU contributed to HCC migration and epithelial-mesenchymal transition (EMT) in vitro, and metastasis in vivo. In addition, sCLU also plays an important role in the regulation of TGF-β1-smad3 signaling. These findings suggest that sCLU may promote HCC metastasis via the induction of EMT process and may be a candidate target for HCC therapy.
肝细胞癌（HCC）是癌症死亡的第三大主要原因。转移是导致 HCC 死亡的主要关注点。本研究的目的是使用原位异种移植肿瘤模型鉴定 HCC 转移过程中血清中的肿瘤衍生蛋白，并探讨关键蛋白在 HCC 转移中的作用。从 HCCLM3-R 转移性 HCC 肿瘤模型在转移特定阶段（1 周、3 周和 6 周）收集的血清样本进行 iTRAQ 标记，然后进行 2DLC-ESI-MS/MS 分析。通过人类特异性肽鉴定了 20 种肿瘤衍生蛋白。在癌症进展和转移过程中显著上调的分泌性簇蛋白（sCLU）被选择用于进一步研究。sCLU 在转移性 HCC 细胞系和转移性 HCC 患者的样本中的表达明显升高。sCLU 的 shRNA 介导下调导致 HCC 细胞系迁移能力降低，体内肺转移减少。在 HepG2 细胞系中过表达 sCLU 显示出增强的细胞迁移能力。进一步的研究发现，sCLU 在体外促进 HCC 迁移和上皮间质转化（EMT），并在体内转移。此外，sCLU 还在 TGF-β1-smad3 信号通路的调节中发挥重要作用。这些发现表明 sCLU 可能通过诱导 EMT 过程促进 HCC 转移，可能是 HCC 治疗的候选靶点。
