Inhibition of renalase expression and signaling has antitumor activity in pancreatic cancer.

An essential feature of cancer is dysregulation of cell senescence and death. Renalase, a recently discovered secreted flavoprotein, provides cytoprotection against ischemic and toxic cellular injury by signaling through the PI3K-AKT and MAPK pathways. Here we show that renalase expression is increased in pancreatic cancer tissue and that it functions as a growth factor. In a cohort of patients with pancreatic ductal adenocarcinoma, overall survival was inversely correlated with renalase expression in the tumor mass, suggesting a pathogenic role for renalase. Inhibition of renalase signaling using siRNA or inhibitory anti-renalase antibodies decreased the viability of cultured pancreatic ductal adenocarcinoma cells. In two xenograft mouse models, either the renalase monoclonal antibody m28-RNLS or shRNA knockdown of renalase inhibited pancreatic ductal adenocarcinoma growth. Inhibition of renalase caused tumor cell apoptosis and cell cycle arrest. These results reveal a previously unrecognized role for the renalase in cancer: its expression may serve as a prognostic maker and its inhibition may provide an attractive therapeutic target in pancreatic cancer.