Regulation of amphiregulin gene expression by β-catenin signaling in human hepatocellular carcinoma cells: a novel crosstalk between FGF19 and the EGFR system

PLoS One. 2012;7(12):e52711. doi: 10.1371/journal.pone.0052711. Epub 2012 Dec 20.

Abstract

Hepatocellular carcinoma (HCC) is the most prevalent liver tumor and a deadly disease with limited therapeutic options. Dysregulation of cell signaling pathways is a common denominator in tumorigenesis, including hepatocarcinogenesis. The epidermal growth factor receptor (EGFR) signaling system is commonly activated in HCC, and is currently being evaluated as a therapeutic target in combination therapies. We and others have identified a central role for the EGFR ligand amphiregulin (AR) in the proliferation, survival and drug resistance of HCC cells. AR expression is frequently up-regulated in HCC tissues and cells through mechanisms not completely known. Here we identify the β-catenin signaling pathway as a novel mechanism leading to transcriptional activation of the AR gene in human HCC cells. Activation of β-catenin signaling, or expression of the T41A β-catenin active mutant, led to the induction of AR expression involving three specific β-catenin-Tcf responsive elements in its proximal promoter. We demonstrate that HCC cells expressing the T41A β-catenin active mutant show enhanced proliferation that is dependent in part on AR expression and EGFR signaling. We also demonstrate here a novel cross-talk of the EGFR system with fibroblast growth factor 19 (FGF19). FGF19 is a recently identified driver gene in hepatocarcinogenesis and an activator of β-catenin signaling in HCC and colon cancer cells. We show that FGF19 induced AR gene expression through the β-catenin pathway in human HCC cells. Importantly, AR up-regulation and EGFR signaling participated in the induction of cyclin D1 and cell proliferation elicited by FGF19. Finally, we demonstrate a positive correlation between FGF19 and AR expression in human HCC tissues, therefore supporting in clinical samples our experimental observations. These findings identify the AR/EGFR system as a key mediator of FGF19 responses in HCC cells involving β-catenin signaling, and suggest that combined targeting of FGF19 and AR/EGFR may enhance therapeutic efficacy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amphiregulin
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism
  • Carcinoma, Hepatocellular / genetics*
  • Carcinoma, Hepatocellular / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation
  • Cyclin D1 / metabolism
  • EGF Family of Proteins
  • ErbB Receptors / metabolism
  • Fibroblast Growth Factors / metabolism
  • Gene Expression Regulation, Neoplastic
  • Glycoproteins / genetics*
  • Glycoproteins / metabolism
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics*
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Liver Neoplasms / genetics*
  • Liver Neoplasms / metabolism*
  • Mutation
  • Prognosis
  • Promoter Regions, Genetic
  • Signal Transduction*
  • Transcription Factor 4
  • Transcription Factors / metabolism
  • beta Catenin / genetics
  • beta Catenin / metabolism*

Substances

  • AREG protein, human
  • Amphiregulin
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • EGF Family of Proteins
  • FGF19 protein, human
  • Glycoproteins
  • Intercellular Signaling Peptides and Proteins
  • TCF4 protein, human
  • Transcription Factor 4
  • Transcription Factors
  • beta Catenin
  • Cyclin D1
  • Fibroblast Growth Factors
  • ErbB Receptors

Grants and funding

Work in the authors’ laboratory is supported by the agreement between Fundación para la Investigación Médica Aplicada and the “UTE project Centro de Investigación Médica Aplicada”. Red Temática de Investigación Cooperativa en Cáncer RD06 00200061 (CB and MAA), Centro de Investigación Biomédica en Red en el Área temática de Enfermedades Hepáticas y Digestivas (JP), Fundación Echébano, Fundacion Barrié de la Maza y Condesa de Fenosa, and grants Fondo para la Investigación Sanitaria (FIS) PI070392, PI070402, PI10/00038 and PI10/02642 from Instituto de Salud Carlos III. MUL and RU were supported by a “Ramón y Cajal” and a “Torres Quevedo” contract from Ministerio de Educación, respectively. MS was supported by a contract (CP04/00123) from Instituto de Salud Carlos III, FIS. FS was supported by the Erasmus Program (European Union). ME was supported by a fellowship from Gobierno de Navarra. OGI was supported by a Formación del Profesorado Universitario fellowship from Ministerio de Educación, Cultura y Deporte, Spain. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.