Activation of dickkopf-1 and focal adhesion kinase pathway by tumour necrosis factor α induces enhanced migration of fibroblast-like synoviocytes in rheumatoid arthritis

Rheumatology (Oxford). 2016 May;55(5):928-38. doi: 10.1093/rheumatology/kev422. Epub 2015 Dec 29.


Objective: The objective of this study was to investigate the roles of dickkopf-1 (DKK-1) and integrin-related focal adhesion kinase (FAK) by TNF-α on the migration of fibroblast-like synoviocytes (FLSs) in RA.

Methods: Wound scratch assays were performed to assess FLS migration. Western blotting was used to measure the levels of DKK-1, Wnt signalling molecules and FAK signalling molecules. Quantitative real-time PCR was used to measure the expression levels of DKK-1, integrin αv, laminin, fibronectin, E-cadherin, MMP-8 and MMP-13. The concentrations of DKK-1, TNF-α and GSK-3β were measured by ELISA. Genetic silencing of TNF-α was achieved by the transfection of small interfering RNA into cells.

Results: Migrating RA FLSs exhibited higher levels of DKK-1 and TNF-α expression compared with those in OA FLSs and/or stationary RA FLSs. Moreover, migrating FLSs exhibited significantly higher levels of FAK, p-JNK, paxillin and cdc42 expression, whereas the level of cytosolic β-catenin was lower. WAY-262611, Wnt pathway agonist via inhibition of DKK-1, markedly inhibited cell migration of RA FLSs through the accumulation of cytosolic β-catenin and suppression of FAK-related signalling pathways. TNF-α treatment to RA FLSs up-regulated expression of DKK-1, integrin αv, fibronectin, laminin and MMP-13. TNF-α stimulation also suppressed cytosolic β-catenin and E-cadherin expression in a time-dependent manner. Moreover, TNF-α small interfering RNA-transfected migrating FLSs exhibited decreased activation of integrin-related FAK, paxillin, p-JNK and cdc42 signalling pathways.

Conclusion: This study demonstrates that the activation of DKK-1 and the integrin-related FAK signalling pathway stimulated by TNF-α induces the dissociation of β-catenin/E-cadherin, thus promoting RA FLS migration.

Keywords: E-cadherin; dickkopf-1; fibroblast-like synoviocyte; focal adhesion kinase; migration; rheumatoid arthritis; β-catenin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Arthritis, Rheumatoid / metabolism
  • Arthritis, Rheumatoid / pathology*
  • Cadherins / metabolism
  • Cell Movement / physiology
  • Cells, Cultured
  • Female
  • Fibroblasts / physiology
  • Focal Adhesion Kinase 1 / genetics
  • Focal Adhesion Kinase 1 / physiology*
  • Gene Silencing
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / physiology*
  • Middle Aged
  • Osteoarthritis / metabolism
  • Osteoarthritis / pathology
  • RNA, Small Interfering / genetics
  • Signal Transduction / physiology
  • Synovial Membrane / pathology*
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / physiology*
  • beta Catenin / metabolism


  • CTNNB1 protein, human
  • Cadherins
  • DKK1 protein, human
  • Intercellular Signaling Peptides and Proteins
  • RNA, Small Interfering
  • Tumor Necrosis Factor-alpha
  • beta Catenin
  • Focal Adhesion Kinase 1
  • PTK2 protein, human