Adrenomedullin and Its Expression in Cancers and Bone. A Literature Review

Adrenomedullin (ADM) was first isolated from pheochromocytoma tissue as a novel vasodilative peptide in 1993. ADM binds to two receptors on plasma membrane which are comprised of Calcitonin Receptor-Like Receptor (CRLR), a member of serpentine receptor superfamily, and Receptor Activity Modifying Protein (RAMP) type 2 or 3. ADM is known to have hypotensive activity. Recently, ADM has been shown to be an almost ubiquitous peptide, synthesized in many mammalian tissues. ADM has potent in vivo angiogenic activity and tumor growth promoting effect in animal models. Many human tumors express ADM. However, only little information exists regarding the expression or the role of ADM in bone and its effect in bone metabolism. It is still not clear whether ADM is involved in pathogenesis and development of osteosarcoma, the most common form of bone tumor. The purpose of this review is to examine the most salient features of adrenomedullin biology, its expression in tumors and its potential implication in the treatment of bone tumors.