Intestinal FXR Activation via Transgenic Chimera or Chemical Agonism Prevents Colitis-Associated and Genetically-Induced Colon Cancer

Abstract

The Farnesoid X Receptor (FXR) is the master regulator of Bile Acids (BA) homeostasis orchestrating their synthesis, transport and metabolism. Disruption of BA regulation has been linked to gut-liver axis diseases such as colorectal cancer (CRC). In this study, firstly we examined the role of constitutive activation of intestinal FXR in CRC; then we pre-clinically investigated the therapeutic potential of a diet enriched with a synthetic FXR agonist in two models of CRC (chemically-induced and genetic models). We demonstrated that mice with intestinal constitutive FXR activation are protected from AOM/DSS-induced CRC with a significant reduction of tumor number compared to controls. Furthermore, we evaluated the role of chemical FXR agonism in a DSS model of colitis in wild type (WT) and FXRnull mice. WT mice administered with the FXR activating diet showed less morphological alterations and decreased inflammatory infiltrates compared to controls. The FXR activating diet also protected WT mice from AOM/DSS-induced CRC by reducing tumors’ number and size. Finally, we proved that the FXR activating diet prevented spontaneous CRC in APCMin/+ mice via an FXR-dependent modulation of BA homeostasis. Our results demonstrate that intestinal FXR activation prevented both inflammation- and genetically-driven colorectal tumorigenesis by modulating BA pool size and composition. This could open new avenues for the therapeutic management of intestinal inflammation and tumorigenesis.