VASCULAR ENDOTHELIAL GROWTH-FACTOR INDUCES INTERSTITIAL COLLAGENASE EXPRESSION IN HUMAN ENDOTHELIAL-CELLS

Vascular endothelial growth factor (VEGF) is a 45kDa secreted peptide that has potent mitogenic activity specific for endothelial cells in vitro and the ability to induce a strong angiogenic response in vivo. In the present study, 24 h treatment with VEGF resulted in a stimulation of expression of the metalloproteinase, interstitial collagenase, at the protein and mRNA levels 2.5-3.0-fold in human umbilical vein endothelial cells but not in human dermal fibroblasts. The dose response curve for collagenase induction was biphasic with the peak stimulatory response obtained by treatment of cells with 10-1 00 ng/ml (0.2-2 nM) VEGF. The dose response curve for collagenase induction overlapped with, but was not identical to, the response curve for proliferation, which showed VEGF mitogenic activity between less-than-or-equal-to 0.1-50 ng/ml (less-than-or-equal-to 0.002-1 nM). There was no induction seen in expression of other members of the matrix metalloproteinase family, including the 72kDa type IV collagenase, the 92kDa type V collagenase, or stromelysin. Expression of transcripts for the major metalloproteinase inhibitor, tissue inhibitor of metalloproteinases, was also unaltered by treatment with VEGF (1-200 ng/ml). These studies demonstrate that in addition to stimulating proliferation of endothelial cells, VEGF can also induce the expression of the only metalloproteinase that can initiate degradation of interstitial collagen types I-III under normal physiological conditions. Both responses are likely to contribute to the angiogenic potential of this peptide.