title: Chemoproteomic Screening of Covalent Ligands Reveals UBA5 As a Novel Pancreatic Cancer Target.
abstract: Chemical genetic screening of small-molecule libraries has been a promising strategy for discovering unique and novel therapeutic compounds. However, identifying the targets of lead molecules that arise from these screens has remained a major bottleneck in understanding the mechanism of action of these compounds. Here, we have coupled the screening of a cysteine-reactive fragment-based covalent ligand library with an isotopic tandem orthogonal proteolysis-enabled activity-based protein profiling (isoTOP-ABPP) chemoproteomic platform to rapidly couple the discovery of lead small molecules that impair pancreatic cancer pathogenicity with the identification of druggable hotspots for potential cancer therapy. Through this coupled approach, we have discovered a covalent ligand DKM 2-93 that impairs pancreatic cancer cell survival and in vivo tumor growth through covalently modifying the catalytic cysteine of the ubiquitin-like modifier activating enzyme 5 (UBA5), thereby inhibiting its activity as a protein that activates the ubiquitin-like protein UFM1 to UFMylate proteins. We show that UBA5 is a novel pancreatic cancer therapeutic target and show DKM 2-93 as a relatively selective lead inhibitor of UBA5. Our results underscore the utility of coupling the screening of covalent ligand libraries with isoTOP-ABPP platforms for mining the proteome for druggable hotspots for cancer therapy.
authors.affiliation: Departments of Chemistry, Molecular and Cell Biology, and Nutritional Sciences and Toxicology, 127 Morgan Hall, University of California, Berkeley , Berkeley, California 94720, United States.
authors.forename: Allison M
authors.initials: AM
authors.lastname: Roberts
authors.affiliation: Departments of Chemistry, Molecular and Cell Biology, and Nutritional Sciences and Toxicology, 127 Morgan Hall, University of California, Berkeley , Berkeley, California 94720, United States.
authors.forename: David K
authors.initials: DK
authors.lastname: Miyamoto
authors.affiliation: Departments of Chemistry, Molecular and Cell Biology, and Nutritional Sciences and Toxicology, 127 Morgan Hall, University of California, Berkeley , Berkeley, California 94720, United States.
authors.forename: Tucker R
authors.initials: TR
authors.lastname: Huffman
authors.affiliation: Departments of Chemistry, Molecular and Cell Biology, and Nutritional Sciences and Toxicology, 127 Morgan Hall, University of California, Berkeley , Berkeley, California 94720, United States.
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Bateman
authors.affiliation: Departments of Chemistry, Molecular and Cell Biology, and Nutritional Sciences and Toxicology, 127 Morgan Hall, University of California, Berkeley , Berkeley, California 94720, United States.
authors.forename: Ashley N
authors.initials: AN
authors.lastname: Ives
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley , Berkeley, California 94720, United States.
authors.forename: David
authors.initials: D
authors.lastname: Akopian
authors.affiliation: The University of Alabama at Birmingham , Birmingham, Alabama 35233, United States.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Heslin
authors.affiliation: The University of Alabama at Birmingham , Birmingham, Alabama 35233, United States.
authors.forename: Carlo M
authors.initials: CM
authors.lastname: Contreras
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley , Berkeley, California 94720, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Rape
authors.affiliation: The University of Alabama at Birmingham , Birmingham, Alabama 35233, United States.
authors.forename: Christine F
authors.initials: CF
authors.lastname: Skibola
authors.affiliation: Departments of Chemistry, Molecular and Cell Biology, and Nutritional Sciences and Toxicology, 127 Morgan Hall, University of California, Berkeley , Berkeley, California 94720, United States.
authors.forename: Daniel K
authors.identifier: 0000-0003-1614-8360
authors.initials: DK
authors.lastname: Nomura
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D055785:Gene Knockdown Techniques; D006801:Humans; D008024:Ligands; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D040901:Proteomics; D044764:Ubiquitin-Activating Enzymes / Q000187:drug effects* / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D008024:Ligands; C502095:UBA5 protein, human; D044764:Ubiquitin-Activating Enzymes