Porcupine inhibitors: Novel and emerging anti-cancer therapeutics targeting the Wnt signaling pathway

Porcupine is a constituent of the 19 membered Wnt family with diverse biological features such as cell differentiation, cell proliferation, cell migration, apoptosis, etc. Porcupine is a membrane-bound o-acyltransferase family protein that modulates Wnt protein through palmitoylation to allow it to depart the secretory pathway and activate cellular responses. Inhibition of Porcupine prevents palmitoylation of Wnt ligands which in turn blocks the transport of Wnt to the extracellular membrane, thus prevents the immoderate production of beta-catenin which helps to control the aberrant cell growth. Clinically, Porcupine inhibitors have shown their potential in treating majorly colorectal cancer, pancreatic cancer, hepatocellular carcinoma, head and neck cancer etc. Till date, none of the Porcupine inhibitors have been in the market and only four molecules, LGK974, ETC159, CGX1321 and RXC004 have reached the Phase I clinical trial. Present review gives a comprehensive insight on Porcupine as a novel drug target for the treatment of cancer as well as recent update on many novel heterocyclic Porcupine inhibitors with their chemical structures and pharmacology. Their physico chemical properties were also predicted using SwissADME server. Major concerns during their development have also been summarised which may throw some light for the future development of novel Porcupine inhibitors for the treatment of cancer.