Discovery of a dual Ras and ARF6 inhibitor from a GPCR endocytosis screen

• Published in: Nature communications Vol. 12; no. 1; p. 4688
• Main Authors: Giubilaro, Jenna, Schuetz, Doris A., Stepniewski, Tomasz M., Namkung, Yoon, Khoury, Etienne, Lara-Márquez, Mónica, Campbell, Shirley, Beautrait, Alexandre, Armando, Sylvain, Radresa, Olivier, Duchaine, Jean, Lamarche-Vane, Nathalie, Claing, Audrey, Selent, Jana, Bouvier, Michel, Marinier, Anne, Laporte, Stéphane A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03.08.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 13/95; 49/47; 49/98; 631/80/86/2363; 631/92/507; 9/10; Agonists; AKT protein; Angiotensin; Angiotensin II; Binding; Cancer; Cell proliferation; Coupling (molecular); Endocytosis; G protein-coupled receptors; Humanities and Social Sciences; Inhibitors; Internalization; Kinases; MAP kinase; multidisciplinary; Protein transport; Proteins; Receptors; Science; Science (multidisciplinary); Signaling
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-24968-y

Internalization and intracellular trafficking of G protein-coupled receptors (GPCRs) play pivotal roles in cell responsiveness. Dysregulation in receptor trafficking can lead to aberrant signaling and cell behavior. Here, using an endosomal BRET-based assay in a high-throughput screen with the prototypical GPCR angiotensin II type 1 receptor (AT1R), we sought to identify receptor trafficking inhibitors from a library of ~115,000 small molecules. We identified a novel dual Ras and ARF6 inhibitor, which we named Rasarfin, that blocks agonist-mediated internalization of AT1R and other GPCRs. Rasarfin also potently inhibits agonist-induced ERK1/2 signaling by GPCRs, and MAPK and Akt signaling by EGFR, as well as prevents cancer cell proliferation. In silico modeling and in vitro studies reveal a unique binding modality of Rasarfin within the SOS-binding domain of Ras. Our findings unveil a class of dual small G protein inhibitors for receptor trafficking and signaling, useful for the inhibition of oncogenic cellular responses. While Ras is a promising target for cancer therapy, development of inhibitors targeting Ras signaling has proven challenging. Here, the authors report the discovery of Rasarfin, a small molecule from a phenotypic screen on G protein-coupled receptor (GPCR) endocytosis that acts as a dual Ras and ARF6 inhibitor.