ETS-1 converts endothelial cells to the angiogenic phenotype by inducing the expression of matrix metalloproteinases and integrin β₃

The transcription factor ETS-1 is induced in endothelial cells (ECs) by angiogenic growth factors and the specific elimination of ETS-1 synthesis by antisense oligodeoxynucleotide inhibited angiogenesis in vitro (Iwasaka et al., 1996, J Cell Physiol 169:522-531). To understand the precise role of ETS-1 in angiogenesis, we established both high and low ETS-1 expression EC lines and compared angiogenic properties of these cell lines with those of the parental murine EC line, MSS-31. Although growth rate was almost identical for each cell line, the invasiveness was markedly enhanced in high ETS-1 expression cells and reduced in low ETS-1 expression cells compared with that of parental cells. The gene expressions of matrix metalloproteinases (MMP-1, MMP-3, and MMP-9)and gelatinolytic activity of MMP-9 were significantly increased in high ETS-1 expression cells. Low ETS-1 expression cells could not spread on a vitronectin substratum, and the phosphorylation of focal adhesion kinase was markedly impaired because of the reduced expression of integrin β₃. These results indicate that ETS-1 is a principal regulator that converts ECs to the angiogenic phenotype.