Urocortin stimulates the ERK1/2 signaling pathway and the proliferation of HeLa cells via CRF receptor 1

Corticotropin‐releasing factor (CRF) stimulates adrenocorticotropic hormone (ACTH) secretion from the pituitary gland and is an essential regulator of the hypothalamic–pituitary–adrenocortical axis. Isoforms of CRF receptor are known to mediate the effects of urocortin stress ligands on the regulation of stress responses, anxiety, and feeding behavior; however, urocortin stress ligands also influence cell proliferation. In view of the tumor‐promoting capacity of prolonged stress, here we investigated (a) the effect of urocortin on cell proliferative signaling via extracellular signal‐regulated kinase 1/2, (b) the expression and cellular distribution of the specific CRF receptor isoforms, and (c) the intracellular localization of phosphorylated ERK1/2 in HeLa cells. Stimulation of cell proliferation was observed in the presence of 10 nm urocortin. Our data also suggest that MAP kinase MEK, the transcription factors E2F‐1 and p53, and PKB/Akt are involved in this process. These findings may have therapeutic relevance for the targeted treatment of various malignancies.