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

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Colleges, School and Institutes


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.


Original languageEnglish
Pages (from-to)697-702
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number3
Publication statusPublished - 25 Apr 1996


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