Regulation of angiogenesis by growth factors

Normal angiogenesis is self-limiting and strictly regulated while tumor angiogenesis appears to be deregulated. Angiogenesis proceeds upon a balance of angiogenic factors and inhibitors, with which expression of plasminogen activator (PA) and its inhibitor is closely associated. Angiogenic factors such as fibroblast growth factors, epidermal growth factor/transforming growth factor (TGF)-α, and vascular endothelial growth factor induce cell migration, tubulogenesis, and PA. By contrast) anti-angiogenic factors such as TGF-β and tumor necrosis factor-α inhibit cell migration tubulogenesis and expression of PA. In this article, we discuss how such angiogenic factors and anti-angiogenic factors modulate angiogenesis in model systems.