The oncogenic effect of sulfatase 2 in human hepatocellular carcinoma is mediated in part by glypican 3-dependent Wnt activation.

Academic Article

Abstract

  • UNLABELLED: Heparan sulfate proteoglycans (HSPGs) act as coreceptors or storage sites for growth factors and cytokines such as fibroblast growth factor and Wnts. Glypican 3 (GPC3) is the most highly expressed HSPG in hepatocellular carcinoma (HCC). Sulfatase 2 (SULF2), an enzyme with 6-O-desulfatase activity on HSPGs, is up-regulated in 60% of primary HCCs and is associated with a worse prognosis. We have previously shown that the oncogenic effect of SULF2 in HCC may be mediated in part through up-regulation of GPC3. Here we demonstrate that GPC3 stimulates the Wnt/β-catenin pathway and mediates the oncogenic function of SULF2 in HCC. Wnt signaling in vitro and in vivo was assessed in SULF2-negative Hep3B HCC cells transfected with SULF2 and in SULF2-expressing Huh7 cells transfected with short hairpin RNA targeting SULF2. The interaction between GPC3, SULF2, and Wnt3a was assessed by coimmunoprecipitation and flow cytometry. β-catenin-dependent transcriptional activity was assessed with the TOPFLASH (T cell factor reporter plasmid) luciferase assay. In HCC cells, SULF2 increased cell surface GPC3 and Wnt3a expression, stabilized β-catenin, and activated T cell factor transcription factor activity and expression of the Wnt/β-catenin target gene cyclin D1. Opposite effects were observed in SULF2-knockdown models. In vivo, nude mouse xenografts established from SULF2-transfected Hep3B cells showed enhanced GPC3, Wnt3a, and β-catenin levels. CONCLUSION: Together, these findings identify a novel mechanism mediating the oncogenic function of SULF2 in HCC that includes GPC3-mediated activation of Wnt signaling via the Wnt3a/glycogen synthase kinase 3 beta axis.
  • Authors

  • Lai, Jin-Ping
  • Oseini, Abdul M
  • Moser, Catherine D
  • Yu, Chunrong
  • Elsawa, Sherine
  • Hu, Chunling
  • Nakamura, Ikuo
  • Han, Tao
  • Aderca, Ileana
  • Isomoto, Hajime
  • Garrity-Park, Megan M
  • Shire, Abdirashid M
  • Li, Jia
  • Sanderson, Schuyler O
  • Adjei, Alex A
  • Fernandez-Zapico, Martin E
  • Roberts, Lewis R
  • Status

    Publication Date

  • November 2010
  • Published In

  • Hepatology  Journal
  • Keywords

  • Animals
  • Carcinoma, Hepatocellular
  • Caspase 3
  • Cell Line, Tumor
  • Enzyme Activation
  • Flow Cytometry
  • Gene Expression Regulation, Neoplastic
  • Genes, Reporter
  • Glypicans
  • Humans
  • Ki-67 Antigen
  • Liver Neoplasms
  • Luciferases
  • Mice
  • Mice, Nude
  • Plasmids
  • Sulfotransferases
  • Transfection
  • Wnt Proteins
  • Wnt3 Protein
  • Wnt3A Protein
  • Digital Object Identifier (doi)

    Start Page

  • 1680
  • End Page

  • 1689
  • Volume

  • 52
  • Issue

  • 5