β-Catenin/CBP inhibition alters epidermal growth factor receptor fucosylation status in oral squamous cell carcinoma

Mol Omics. 2020 Jun 1;16(3):195-209. doi: 10.1039/d0mo00009d. Epub 2020 Mar 23.

Abstract

Epidermal growth factor receptor (EGFR) is a major driver of head and neck cancer, a devastating malignancy with a major sub-site in the oral cavity manifesting as oral squamous cell carcinoma (OSCC). EGFR is a glycoprotein receptor tyrosine kinase (RTK) whose activity is upregulated in >80% OSCC. Current anti-EGFR therapy relies on the use of cetuximab, a monoclonal antibody against EGFR, although it has had only a limited response in patients. Here, we uncover a novel mechanism regulating EGFR activity, identifying a role of the nuclear branch of the Wnt/β-catenin signaling pathway, the β-catenin/CBP axis, in control of post-translational modification of N-glycans on the EGFR. Genomic and structural analyses reveal that β-catenin/CBP signaling represses fucosylation on the antennae of N-linked glycans on EGFR. By employing nUPLC-MS/MS, we determined that malignant human OSCC cells harbor EGFR with a paucity of N-glycan antennary fucosylation, while indolent cells display higher levels of fucosylation at sites N420 and N579. Additionally, treatment with either ICG-001 or E7386, which are both small molecule inhibitors of β-catenin/CBP signaling, leads to increased transcriptional expression of fucosyltransferases FUT2 and FUT3, with a concomitant increase in EGFR N-glycan antennary fucosylation. In order to discover which fucosylated glycan epitopes are involved in the observed effect, we performed in-depth characterization of multiply-fucosylated N-glycans via tandem mass spectrometry analysis of the EGFR tryptic glycopeptides. Data are available via ProteomeXchange with identifier PXD017060. We propose that β-catenin/CBP signaling promotes EGFR oncogenic activity in OSCC by inhibiting its N-glycan antennary fucosylation through transcriptional repression of FUT2 and FUT3.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Bridged Bicyclo Compounds, Heterocyclic / administration & dosage
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology
  • CREB-Binding Protein / metabolism
  • Carcinoma, Squamous Cell / drug therapy*
  • Carcinoma, Squamous Cell / metabolism
  • Cell Line, Tumor
  • ErbB Receptors / chemistry
  • ErbB Receptors / metabolism
  • Fucose / metabolism*
  • Fucosyltransferases / genetics*
  • Fucosyltransferases / metabolism
  • Galactoside 2-alpha-L-fucosyltransferase
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Mice
  • Models, Molecular
  • Mouth Neoplasms / drug therapy*
  • Mouth Neoplasms / genetics
  • Mouth Neoplasms / metabolism
  • Neoplasm Metastasis
  • Polysaccharides / metabolism
  • Protein Structure, Tertiary
  • Pyrimidinones / administration & dosage
  • Pyrimidinones / pharmacology
  • Small Molecule Libraries / administration & dosage*
  • Small Molecule Libraries / pharmacology
  • Wnt Signaling Pathway / drug effects
  • Xenograft Model Antitumor Assays
  • beta Catenin / metabolism

Substances

  • Bridged Bicyclo Compounds, Heterocyclic
  • CTNNB1 protein, human
  • ICG 001
  • Polysaccharides
  • Pyrimidinones
  • Small Molecule Libraries
  • beta Catenin
  • Fucose
  • CREB-Binding Protein
  • CREBBP protein, human
  • Fucosyltransferases
  • 3-galactosyl-N-acetylglucosaminide 4-alpha-L-fucosyltransferase
  • EGFR protein, human
  • ErbB Receptors