Protein-serine O-palmitoleoyltransferase porcupine and Multiple receptor tyrosine kinases (PORCN + RTKs)

Protein-serine O-palmitoleoyltransferase porcupine (PORCN) is a membrane-bound O-acyltransferase located in the endoplasmic reticulum that is essential for the post-translational modification of Wnt proteins (UniProt: Q9H237). It catalyzes the palmitoylation of Wnt ligands, a step strictly required for their secretion and ability to activate Wnt signaling pathways, which govern cell proliferation, differentiation, and tissue homeostasis (PubMed: 23023377). Receptor tyrosine kinases (RTKs) are a diverse group of high-affinity cell surface receptors for many polypeptide growth factors, cytokines, and hormones, playing critical roles in cell growth and survival signaling (PubMed: 20813259). The combination of Porcupine and multiple receptor tyrosine kinases represents a multi-target therapeutic approach designed to disrupt the complex crosstalk between Wnt and RTK signaling pathways, which often drives tumor progression and drug resistance (PubMed: 30333116). In many cancers, such as colorectal and biliary tract carcinomas, aberrant Wnt signaling can bypass RTK inhibition, making the dual targeting of PORCN and RTKs a promising strategy to enhance clinical efficacy (PubMed: 28249908). Current clinical candidates like RXC004 and CGX1321 are being investigated for their ability to inhibit Porcupine, often in contexts where RTK signaling is also a relevant driver (ClinicalTrials.gov: NCT03447470).

Other names

PORCNPorcupine homologMG61PORCPPNMBOATReceptor Tyrosine Kinase familyRTK family

Porcupine inhibitors bind to the PORCN enzyme to block Wnt palmitoylation and secretion, thereby inhibiting Wnt-driven signaling (PubMed: 23023377). Receptor tyrosine kinase inhibitors block the intracellular kinase activity of RTKs, preventing the activation of downstream growth and survival pathways like MAPK and PI3K (PubMed: 20813259).