Vascular endocan is preferentially expressed in tumor endothelium

Microvasc Res. 2006 Nov;72(3):136-45. doi: 10.1016/j.mvr.2006.05.010. Epub 2006 Sep 7.


Endothelial cell phenotypes are differentially regulated between different sites of the vascular tree. We tested the hypothesis that endocan, a novel soluble dermatan sulfate proteoglycan, is differentially expressed in the intact endothelium and that site-specific expression is mediated by signals in the local microenvironment. Using a combination of Northern blot analyses, Taqman RT-PCR, and in situ hybridizations, endocan was shown to be preferentially expressed in the endothelial lining of tumor xenografts, including human non-small cell lung cancer, rat glioma, and human renal cell carcinoma. In contrast, endocan mRNA was expressed at low levels in embryos between E4.5 and E18.5. Under in vitro conditions, endocan expression in human umbilical vein endothelial cells (HUVEC) was upregulated by tumor cell-conditioned medium, an effect that was inhibited by the addition of neutralizing antibody to vascular endothelial growth factor (VEGF). Moreover, treatment of HUVEC with VEGF resulted in a dose- and time-dependent increase in endocan mRNA. The results suggest that endocan is preferentially expressed in tumor endothelium in vivo and that its expression is regulated by tumor-derived factors.

Publication types

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

MeSH terms

  • Animals
  • Blotting, Northern
  • Cell Line, Tumor
  • Cells, Cultured
  • Culture Media, Conditioned / pharmacology
  • Embryo, Mammalian / metabolism
  • Endothelial Cells / cytology
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / metabolism*
  • Forkhead Box Protein O3
  • Forkhead Transcription Factors / genetics
  • Gene Expression Profiling*
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / genetics
  • Gene Expression Regulation, Developmental / genetics
  • Humans
  • In Situ Hybridization
  • Mice
  • Mice, Inbred Strains
  • Neoplasm Proteins / genetics
  • Neoplasms, Experimental / blood supply
  • Neoplasms, Experimental / genetics*
  • Neoplasms, Experimental / pathology
  • Platelet Endothelial Cell Adhesion Molecule-1 / genetics
  • Proteoglycans / genetics*
  • Proto-Oncogene Proteins c-akt / genetics
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / pharmacology
  • von Willebrand Factor / genetics


  • Culture Media, Conditioned
  • ESM1 protein, human
  • FOXO3 protein, human
  • Forkhead Box Protein O3
  • Forkhead Transcription Factors
  • Neoplasm Proteins
  • Platelet Endothelial Cell Adhesion Molecule-1
  • Proteoglycans
  • RNA, Messenger
  • Vascular Endothelial Growth Factor A
  • endothelial cell-specific molecule-1, mouse
  • von Willebrand Factor
  • Proto-Oncogene Proteins c-akt