Expression of Urocortin I in Normal Tissues and Malignant Tumors

Corticotropin-releasing factor (CRF) is a key player in the hypothalamus-pituitary adrenal axis, and exerts its actions through two types of receptors: CRF type 1 and type 2 (CRF1 and CRF2) receptors. After the discovery of CRF and these receptors, a CRF-related peptide, urocortin I (UCN I), was identified. UCN I is a more potent agonist than CRF on CRF receptors, especially CRF2, which is involved in stress response. UCN I has various beneficial actions and is distributed in central and peripheral normal tissues, including the brain, heart, vascular cells, and endometrium. Recently, UCN I expression was also discovered in malignant cells, such as human glioblastoma cells, pituitary adenoma cells, hepatic carcinoma cells, gastric cancer cells, adrenocortical adenoma cells, and renal clear-cell carcinoma cells. Recent developments into the pathophysiological roles of UCN I and its related peptides will potentially lead to new anticancer therapies. Here, we review the expression of UCN I in normal and malignant cells and discuss the future of UCNs in anticancer therapy.