Knock-down of CD44 regulates endothelial cell differentiation via NFκB-mediated chemokine production

PLoS One. 2014 Mar 10;9(3):e90921. doi: 10.1371/journal.pone.0090921. eCollection 2014.


A striking feature of microvascular endothelial cells is their capacity to fuse and differentiate into tubular structures when grown in three-dimensional (3D) extracellular matrices, in collagen or Matrigel, mimicking the in vivo blood vessel formation. In this study we demonstrate that human telomerase-immortalised foreskin microvascular endothelial (TIME) cells express high levels of the hyaluronan receptor CD44 and the hyaluronidase HYAL2. Knock-down of CD44 or HYAL2 resulted in an inability of TIME cells to form a tubular network, suggesting a key regulatory role of hyaluronan in controlling TIME cell tubulogenesis in 3D matrices. Knock-down of CD44 resulted in an upregulation of mRNA expression of the chemokines CXCL9 and CXCL12, as well as their receptors CXCR3 and CXCR4. This was accompanied by a defect maturation of the tubular structure network and increased phosphorylation of the inhibitor of NFκB kinase (IKK) complex and thus translocation of NFκB into the nucleus and activation of chemokine targed genes. Furthermore, the interaction between CD44 and hyaluronan determines the adhesion of breast cancer cells. In summary, our observations support the notion that the interaction between CD44 and hyaluronan regulates microvascular endothelial cell tubulogenesis by affecting the expression of cytokines and their receptors, as well as breast cancer dissemination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Adhesion
  • Cell Adhesion Molecules / metabolism
  • Cell Differentiation*
  • Cell Line, Tumor
  • Chemokine CXCL12 / metabolism*
  • Chemokine CXCL9 / metabolism*
  • Endothelial Cells / cytology*
  • Endothelial Cells / metabolism*
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • GPI-Linked Proteins / metabolism
  • Gene Expression Regulation
  • Gene Knockdown Techniques*
  • Gene Silencing
  • Humans
  • Hyaluronan Receptors / metabolism*
  • Hyaluronic Acid / metabolism
  • Hyaluronoglucosaminidase / metabolism
  • Male
  • Membrane Fusion
  • Microvessels / cytology
  • NF-kappa B / metabolism*
  • Neovascularization, Physiologic
  • Protein Transport
  • Receptors, Chemokine / metabolism
  • Signal Transduction
  • Telomerase / metabolism
  • Vacuoles / metabolism


  • Cell Adhesion Molecules
  • Chemokine CXCL12
  • Chemokine CXCL9
  • GPI-Linked Proteins
  • Hyaluronan Receptors
  • NF-kappa B
  • Receptors, Chemokine
  • Hyaluronic Acid
  • Extracellular Signal-Regulated MAP Kinases
  • Telomerase
  • Hyal2 protein, human
  • Hyaluronoglucosaminidase

Grant support

The work was supported by grants from the Swedish Cancer Society (; Agnes and Mac Rudbergs Foundation Gurli and Edward Brunnberg Foundation (Uppsala University,; Ludwig Cancer Research ( The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.