Coexpression of flt-1, flt-4 and KDR in freshly isolated and cultured human endothelial cells

Biochem Biophys Res Commun. 1996 Apr 25;221(3):697-702. doi: 10.1006/bbrc.1996.0659.


Vascular endothelial cell growth factors (VEGF) are key modulators of endothelial cell growth and function. The class III receptor tyrosine kinases KDR and Flt-1 are high affinity receptors for VEGF, while Flt-4 is a receptor for the recently identified VEGF-C. We have examined the expression of flt-1, flt-4 and KDR in human microvascular and large vessel endothelial cells and in a variety of other cell types in vitro. Endothelial cells proliferated and exhibited increased procoagulant activity in response to VEGF. Flt-1, flt-4 and KDR were detected in both freshly isolated endothelial cells, and in sparse and confluent endothelial cell cultures by RT-PCR. Attempts to modulate receptor expression by culturing cells at reduced oxygen tensions (2%) did not induce consistent changes in flt-1, flt-4 or KDR expression. Incubation with tumor-conditioned medium or co-culture of endothelial cells with a range of breast and small cell lung carcinoma cell lines did not reproducibly alter receptor mRNA expression. However, flt-1, flt-4 and KDR transcript levels were enhanced following treatment with tetradecanoylphorbol acetate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cells, Cultured
  • DNA Primers
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / metabolism*
  • Humans
  • Molecular Sequence Data
  • Receptor Protein-Tyrosine Kinases / genetics*
  • Receptors, Growth Factor / genetics*


  • DNA Primers
  • Receptors, Growth Factor
  • Receptor Protein-Tyrosine Kinases