Farnesoid X Receptor (FXR) from normal to malignant state.

The Farnesoid X Receptor (FXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors, which plays crucial role in bile acid, cholesterol, lipid and glucose metabolism, as well as in the development of atherosclerosis, intestinal bacterial growth and liver regeneration. FXR is also involved in the pathogenesis of cholestatic diseases, non-alcoholic fatty liver disease and inflammatory bowel disease. Recent evidence further suggests a key role for FXR in apoptosis and cancer. Notably, FXR deficiency promoted intestinal inflammation and tumorigenesis, suggesting that FXR activation might be a promising strategy in the treatment of colon cancer. FXR deficiency in mice led to the development of spontaneous hepatocarcinomas, while FXR inhibition might represent a novel therapeutic approach in Barett's esophagus. In breast cancer cell lines, FXR agonists down-regulated the breast cancer target gene aromatase. FXR inhibited Leydig tumor growth and progression, supporting evidence that FXR may be an important regulator of androgen homoeostasis. Further studies are required in order to establish possible antitumor effects of this nuclear receptor. Either reactivating or inhibiting FXR expression may represent promising therapeutic strategies in the treatment of certain types of human cancer.