Regulation of the steps of angiogenesis by human head and neck squamous cell carcinomas

Human head and neck squamous cell carcinoma (HNSCC) cell cultures were established to identify the angiogenic factors they produced and how these factors contribute to two steps of the angiogenic process: endothelial cell proliferation and migration. The HNSCC cells secreted vascular endothelial cell growth factor (VEGF), transforming growth factor-beta (TGF-beta) and prostaglandin E2 (PGE2), but only low levels of basic fibroblast growth factor. Both proliferation-stimulatory and -inhibitory cytokines were produced by the HNSCC cells, with VEGF promoting endothelial cell proliferation, prostaglandins having no effect and TGF-beta downregulating proliferation. Two methods were used to measure endothelial cell migration: migration into a wound in the endothelial cell monolayer and migration across a filter into lower compartments. HNSCC cell supernatants stimulated endothelial cell migration in both migration models. VEGF had no effect on the motility of endothelial cells. However, when TGF-beta activity in the HNSCC supernatants was neutralized with antibody or the production of prostaglandins by HNSCC cells was blocked with indomethacin, the migration-stimulatory activity in the HNSCC cell supernatants was diminished. Adding authentic PGE2 or TGF-beta 1 to endothelial cells mimicked the migration-stimulatory activity of the HNSCC supernatants. Thus, HNSCC-derived VEGF is important in stimulating endothelial cell proliferation, while the antiproliferative effect of TGF-beta and the migration-stimulatory activity of TGF-beta and PGE2 suggest their having a role in the morphogenic processes of angiogenesis.