A new family of angiogenic factors

Angiogenesis is the production of new blood vessels from pre-existing ones. This process is tightly regulated by a series of pro- and anti-angiogenic molecules in normal physiology and when this equilibrium is broken serious consequences may arise. Solid tumors are characterized by a fast growth that eventually pushes cells away from their natural source of oxygen and nutrients from the capillaries. To survive in this hypoxic environment, tumor cells secrete a variety of pro-angiogenic molecules that would elicit proliferation of new blood vessels, thus re-establishing oxygen and nutrient supply. Blockade of angiogenesis may provide a rational approach to managing tumor growth and novel strategies are being developed. The identification of new targets is of paramount importance in the search for a clinically proficient anti-angiogenic therapy. The adrenomedullin family of peptides and gastrin-releasing peptide (GRP) are newly identified pro-angiogenic molecules, secreted by the tumors, whose inhibition results in a considerable reduction of angiogenesis and of tumor growth in animal models. The recent identification of small molecules that reduce the angiogenic effect of these peptides opens new avenues for the development of new anti-tumorigenic drugs.