Vascular endothelial growth factor (VEGF) and its receptors in tumor-bearing dogs

The molecular biology of the angiogenic growth factor, vascular endothelial growth factor (VEGF), has been studied in the dog. All major isoforms of V EGF are present in the dog. The amino acid sequences are identical between human and dog in the loop regions that are responsible for receptor binding . Accordingly, the VEGF receptors of dogs and humans are very similar and p erm it functional exchange of the growth factor. Here we show that canine V EGF activates human endothelial cells to the same extent as human VEGF, Sim ilarly, the two proteins display identical cell binding properties, The VEG F receptor 1 (Flt-1) shows the same alternative splicing in humans and dogs and is overexpressed in the majority of tumors in both species, VEGF occur s also in canine tumors in similar relative quantities as in human malignan cies, Based on the literature and our study we suggest that the molecular b iology and the function of the VEGF signaling system are virtually identica l in humans and canines and in healthy as well as in disease conditions.