Blockade of Wnt-1 signaling leads to anti-tumor effects in hepatocellular carcinoma cells

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Hepatocellular carcinoma (HCC) is an aggressive cancer, and is the third leading cause of cancer death worldwide. Standard therapy is ineffective partly because HCC is intrinsically resistant to conventional chemotherapy. Its poor prognosis and limited treatment options make it critical to develop novel and selective chemotherapeutic agents. Since the Wnt/β-catenin pathway is essential in HCC carcinogenesis, we studied the inhibition of Wnt-1-mediated signaling as a potential molecular target in HCC. Results We demonstrated that Wnt-1 is highly expressed in human hepatoma cell lines and a subgroup of human HCC tissues compared to paired adjacent non-tumor tissues. An anti-Wnt-1 antibody dose-dependently decreased viability and proliferation of Huh7 and Hep40 cells over-expressing Wnt-1 and harboring wild type β-catenin, but did not affect normal hepatocytes with undetectable Wnt-1 expression. Apoptosis was also observed in Huh7 and Hep40 cells after treatment with anti-Wnt-1 antibody. In these two cell lines, the anti-Wnt-1 antibody decreased β-catenin/Tcf4 transcriptional activities, which were associated with down-regulation of the endogenous β-catenin/Tcf4 target genes c-Myc, cyclin D1, and survivin. Intratumoral injection of anti-Wnt-1 antibody suppressed in vivo tumor growth in a Huh7 xenograft model, which was also associated with apoptosis and reduced c-Myc, cyclin D1, and survivin expressions. Conclusion Our results suggest that Wnt-1 is a survival factor for HCC cells, and that the blockade of Wnt-1-mediated signaling may offer a potential pathway-specific therapeutic strategy for the treatment of a subgroup of HCC that over-expresses Wnt-1.

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Published 01 January 2009
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Molecular Cancer
Research Blockade of Wnt1 signaling leads to antitumor effects in hepatocellular carcinoma cells 1 1 2 1 Wei Wei , MeiSze Chua* , Susan Grepper and Samuel K So
BioMedCentral
Open Access
1 2 Address: Asian Liver Center, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA and CellzDirect/ Invitrogen, 4301 Emperor Blvd, Durham, NC 27703, USA Email: Wei Wei  weiwei25@stanford.edu; MeiSze Chua*  mchua@stanford.edu; Susan Grepper  sue.grepper@lifetech.com; Samuel K So  samso@stanford.edu * Corresponding author
Published: 24 September 2009 Received: 6 August 2009 Accepted: 24 September 2009 Molecular Cancer2009,8:76 doi:10.1186/14764598876 This article is available from: http://www.molecularcancer.com/content/8/1/76 © 2009 Wei et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract Background:Hepatocellular carcinoma (HCC) is an aggressive cancer, and is the third leading cause of cancer death worldwide. Standard therapy is ineffective partly because HCC is intrinsically resistant to conventional chemotherapy. Its poor prognosis and limited treatment options make it critical to develop novel and selective chemotherapeutic agents. Since the Wnt/βcatenin pathway is essential in HCC carcinogenesis, we studied the inhibition of Wnt1mediated signaling as a potential molecular target in HCC. Results:We demonstrated that Wnt1 is highly expressed in human hepatoma cell lines and a subgroup of human HCC tissues compared to paired adjacent nontumor tissues. An antiWnt1 antibody dosedependently decreased viability and proliferation of Huh7 and Hep40 cells over expressing Wnt1 and harboring wild typeβcatenin, but did not affect normal hepatocytes with undetectable Wnt1 expression. Apoptosis was also observed in Huh7 and Hep40 cells after treatment with antiWnt1 antibody. In these two cell lines, the antiWnt1 antibody decreasedβcatenin/Tcf4 transcriptional activities, which were associated with downregulation of the endogenousβcatenin/Tcf4 target genes cMyc, cyclin D1, and survivin. Intratumoral injection of antiWnt1 antibody suppressedin vivotumor growth in a Huh7 xenograft model, which was also associated with apoptosis and reduced cMyc, cyclin D1, and survivin expressions. Conclusion:Our results suggest that Wnt1 is a survival factor for HCC cells, and that the blockade of Wnt1mediated signaling may offer a potential pathwayspecific therapeutic strategy for the treatment of a subgroup of HCC that overexpresses Wnt1.
Background Hepatocellular carcinoma (HCC) is the primary form of human adult liver cancer. It is the fifth most common can cer worldwide, with about one million new cases diag nosed annually, and almost an equal number of deaths. It is predominant in China, most parts of South East Asia, and South Africa, where hepatitis B virus (HBV) infection
is endemic [1]. The last decade has seen no major advances in the treatment of HCC. Approximately 10 25% of HCC patients are candidates for surgical resection and liver transplantation; the majority of patients have limited treatment options due to the lack of effective chemotherapy against this intrinsically resistant tumor [2 4]. New pharmacological interventions that offer even
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