Pharmacological control of autophagy: therapeutic perspectives in inflammatory bowel disease and colorectal cancer

Abstract

Autophagy, an intracellular process involved in removing and recycling cellular components, plays a major role in growth, development, and responses to stress and pathogens. Autophagy is compromised in many human diseases, including inflammatory bowel disease (IBD) and colorectal cancer (CRC). Autophagy malfunction is associated to an alteration of both innate and adaptative immune responses, defects in bacterial clearance, and malfunction of goblet and Paneth cells; all these perturbations are related to IBD and CRC pathogenesis. Preclinical data show that both inhibition and induction of autophagy have significant potential to be translated into the clinic. Inhibitors of TORC1 (rapamycin and rapalogs) have proven to be effective in IBD and in many models for CRCs; however, their clinical use has produced only modest success. Second generations of mTOR inhibitors, which target its kinase domain, have been more effective. Optimal antitumor efficacy is achieved by combination of agents with different molecular targets, such as proteasome or histone deacetylase inhibitors combined with autophagy inhibitors (hydroxychloroquine) or activators (everolimus). Clinical trials in course are assaying the effect of these compounds in combination with standard treatments of CRC. This review summarizes current knowledge about the autophagic machinery and its regulation, then it explores the relevance and impact of the malfunction of autophagy on the pathogenesis of IBD and CRC, and, finally, it discusses the therapeutic potential of molecules that regulate autophagy and their use for the treatment of these two diseases.