Brief Article
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Jan 21, 2012; 18(3): 244-250
Published online Jan 21, 2012. doi: 10.3748/wjg.v18.i3.244
High level of urokinase plasminogen activator contributes to cholangiocarcinoma invasion and metastasis
Parichut Thummarati, Sitsom Wijitburaphat, Aruna Prasopthum, Apaporn Menakongka, Banchob Sripa, Rutaiwan Tohtong, Tuangporn Suthiphongchai
Parichut Thummarati, Sitsom Wijitburaphat, Aruna Prasopthum, Apaporn Menakongka, Rutaiwan Tohtong, Tuangporn Suthiphongchai, Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
Banchob Sripa, Department of Pathology, Faculty of Medicine, Khon Kaen University, and The Liver Fluke and Cholangiocarcinoma Research Center, Khon Kaen University, Khon Kaen 40002, Thailand
Author contributions: Thummarati P, Wijitburaphat S, Prasopthum A, Menakongka A performed experiments and analyzed data; Thummarati P and Wijitburaphat S contributed equally to this work; Sripa B provided specimens and advice and analyzed the immunohistochemical data; Tohtong R provided valuable suggestions and edited the manuscript; Suthiphongchai T designed the study, analyzed the data, prepared the manuscript and provided financial support for this work.
Supported by Grant from Thailand Research Fund and Faculty of Science, Mahidol University, Thailand (to Suthiphongchai T); Institutional Strengthening Program, Faculty of Science, Mahidol University (to Thummarati P)
Correspondence to: Tuangporn Suthiphongchai, PhD, Associate Professor, Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand. sctsc@mahidol.ac.th
Telephone: +662-2015609 Fax: +662-3547174
Received: June 15, 2011
Revised: August 26, 2011
Accepted: October 28, 2011
Published online: January 21, 2012
Abstract

AIM: To investigate the role of urokinase plasminogen activator (uPA) in cholangiocarcinoma (CCA) invasion and its correlation with clinicopathological parameters.

METHODS: uPA expression in CCA tissue was determined by immunohistochemistry. The level of uPA from two CCA cell lines (HuCCA-1 and KKU-M213) and a non-cancer immortalized cholangiocyte cell line (H69) was monitored by plasminogen-gelatin zymography and western blotting, whereas that of plasminogen activator inhibitor type 1 (PAI-1) protein and uPA receptor (uPAR) mRNA was monitored by western blotting and quantitative real-time reverse transcriptase polymerase chain reaction, respectively. Two independent methods were employed to suppress uPA function: a synthetic uPA inhibitor (B428) and silencing of uPA gene expression using siRNA. In vitro invasion of the uPA-disrupted cells was assessed by Matrigel-coated Transwell assay.

RESULTS: The immunohistochemical study showed that 75.3% (131/174) of CCA tissues expressed uPA. High uPA expression was correlated with lymphatic invasion and metastasis of CCA patients. Plasminogen-gelatin zymography of the conditioned media and cell-surface eluates showed that both CCA cell lines, but not H69, expressed both secreted and membrane-bound forms of uPA. Although the two CCA cell lines, HuCCA-1 and KKU-M213, expressed a relatively high level of uPA and uPAR, the latter exhibited a much lower degree of in vitro invasiveness, correlating with a high expression of PAI-1 in the latter, but not in the former. Suppressing uPA function with a specific uPA inhibitor, B428, or with siRNA against uPA reduced in vitro invasiveness of KKU-M213 cells, demonstrating the requirement for uPA in the invasiveness of CCA cells. Therefore, our in vivo and in vitro studies suggest that uPA is an important requirement for the invasion process of CCA.

CONCLUSION: uPA expression correlates with lymphatic invasion and metastasis in vivo and is required for CCA cell invasion in vitro, suggesting its potential as a therapeutic target.

Keywords: Bile duct cancer; Cholangiocarcinoma; Cancer invasion; Urokinase plasminogen activator; Cancer metastasis