title: The glutaminase activity of L-asparaginase is not required for anticancer activity against ASNS-negative cells.
abstract: L-Asparaginase (L-ASP) is a key component of therapy for acute lymphoblastic leukemia. Its mechanism of action, however, is still poorly understood, in part because of its dual asparaginase and glutaminase activities. Here, we show that L-ASP's glutaminase activity is not always required for the enzyme's anticancer effect. We first used molecular dynamics simulations of the clinically standard Escherichia coli L-ASP to predict what mutated forms could be engineered to retain activity against asparagine but not glutamine. Dynamic mapping of enzyme substrate contacts identified Q59 as a promising mutagenesis target for that purpose. Saturation mutagenesis followed by enzymatic screening identified Q59L as a variant that retains asparaginase activity but shows undetectable glutaminase activity. Unlike wild-type L-ASP, Q59L is inactive against cancer cells that express measurable asparagine synthetase (ASNS). Q59L is potently active, however, against ASNS-negative cells. Those observations indicate that the glutaminase activity of L-ASP is necessary for anticancer activity against ASNS-positive cell types but not ASNS-negative cell types. Because the clinical toxicity of L-ASP is thought to stem from its glutaminase activity, these findings suggest the hypothesis that glutaminase-negative variants of L-ASP would provide larger therapeutic indices than wild-type L-ASP for ASNS-negative cancers.
authors.affiliation: Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX;
authors.forename: Wai Kin
authors.initials: WK
authors.lastname: Chan
authors.affiliation: Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX;
authors.forename: Philip L
authors.identifier: http://orcid.org/0000-0003-0385-7774
authors.initials: PL
authors.lastname: Lorenzi
authors.affiliation: Center for Computational Proteomics, Huck Institute of Life Sciences, Pennsylvania State University, State College, PA;
authors.forename: Andriy
authors.initials: A
authors.lastname: Anishkin
authors.affiliation: Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX;
authors.forename: Preeti
authors.initials: P
authors.lastname: Purwaha
authors.affiliation: Center for Biological and Materials Sciences, Sandia National Laboratories, Albuquerque, NM; and.
authors.forename: David M
authors.initials: DM
authors.lastname: Rogers
authors.affiliation: Department of Biology, University of Maryland, College Park, MD.
authors.forename: Sergei
authors.initials: S
authors.lastname: Sukharev
authors.affiliation: Center for Biological and Materials Sciences, Sandia National Laboratories, Albuquerque, NM; and.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Rempe
authors.affiliation: Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX;
authors.forename: John N
authors.initials: JN
authors.lastname: Weinstein
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000627:therapeutic use*; D001215:Asparaginase / Q000737:chemistry / Q000235:genetics / Q000627:therapeutic use*; D001217:Aspartate-Ammonia Ligase / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology; D005972:Glutaminase / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D020014:K562 Cells; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D016297:Mutagenesis, Site-Directed; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000627:therapeutic use; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D011994:Recombinant Proteins; D001215:Asparaginase; D005972:Glutaminase; D001217:Aspartate-Ammonia Ligase