DIFFERENTIAL EXPRESSION OF THE 2 VEGF RECEPTORS FLT AND KDR IN PLACENTA AND VASCULAR ENDOTHELIAL-CELLS

Vascular endothelial growth factor (VEGF) is a newly identified growth and permeability factor with a unique specificity for endothelial cel ls. Recently the fit-encoded tyrosine kinase was characterized as a re ceptor for VEGF. A novel tyrosine kinase receptor encoded by the KDR g ene was also found to bind VEGF with high affinity when expressed in C MT-3 cells. Screening for fit and KDR expression in a variety of speci es and tissue-derived endothelial cells demonstrates that fit is predo minantly expressed in human placenta and human vascular endothelial ce lls. Placenta growth factor (PlGF), a growth factor significantly rela ted to VEGF, is coexpressed with fit in placenta and human vascular en dothelial cells. KDR is more widely distributed and expressed in all v essel-derived endothelial cells. These data demonstrate that cultured human endothelial cells isolated from different tissues express both V EGF receptors in relative high levels and, additionally, that all inve stigated nonhuman endothelial cells in culture are also positive for K DR gene expression. (C) 1994 Wiley-Liss, Inc.