Matrix metalloproteinases in angiogenesis: a moving target for therapeutic intervention

Abstract

Angiogenesis is the process in which new vessels emerge from existing endothelial lined vessels. This is distinct from the process of vasculogenesis in that the endothelial cells arise by proliferation from existing vessels rather than differentiating from stem cells. Angiogenesis is an invasive process that requires proteolysis of the extracellular matrix and, proliferation and migration of endothelial cells, as well as synthesis of new matrix components. During embryonic development, both vasculogenesis and angiogenesis contribute to formation of the circulatory system. In the adult, with the single exception of the reproductive cycle in women, angiogenesis is initiated only in response to a pathologic condition, such as inflammation or hypoxia. The angiogenic response is critical for progression of wound healing and rheumatoid arthritis. Angiogenesis is also a prerequisite for tumor growth and metastasis formation. Therefore, understanding the cellular events involved in angiogenesis and the molecular regulation of these events has enormous clinical implications. This understanding is providing novel therapeutic targets for the treatment of a variety of diseases, including cancer.