title: Activation Pathway of a Nucleoside Analog Inhibiting Respiratory Syncytial Virus Polymerase.
abstract: Human respiratory syncytial virus (RSV) is a negative-sense RNA virus and a significant cause of respiratory infection in infants and the elderly. No effective vaccines or antiviral therapies are available for the treatment of RSV. ALS-8176 is a first-in-class nucleoside prodrug inhibitor of RSV replication currently under clinical evaluation. ALS-8112, the parent molecule of ALS-8176, undergoes intracellular phosphorylation, yielding the active 5'-triphosphate metabolite. The host kinases responsible for this conversion are not known. Therefore, elucidation of the ALS-8112 activation pathway is key to further understanding its conversion mechanism, particularly given its potent antiviral effects. Here, we have identified the activation pathway of ALS-8112 and show it is unlike other antiviral cytidine analogs. The first step, driven by deoxycytidine kinase (dCK), is highly efficient, while the second step limits the formation of the active 5'-triphosphate species. ALS-8112 is a 2'- and 4'-modified nucleoside analog, prompting us to investigate dCK recognition of other 2'- and 4'-modified nucleosides. Our biochemical approach along with computational modeling contributes to an enhanced structure-activity profile for dCK. These results highlight an exciting potential to optimize nucleoside analogs based on the second activation step and increased attention toward nucleoside diphosphate and triphosphate prodrugs in drug discovery.
authors.affiliation: Alios BioPharma, Inc. , part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Jordan
authors.affiliation: Alios BioPharma, Inc. , part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States.
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Stevens
authors.affiliation: Alios BioPharma, Inc. , part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States.
authors.forename: Yuen
authors.initials: Y
authors.lastname: Tam
authors.affiliation: Alios BioPharma, Inc. , part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Pemberton
authors.affiliation: Alios BioPharma, Inc. , part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States.
authors.forename: Shuvam
authors.initials: S
authors.lastname: Chaudhuri
authors.affiliation: Alios BioPharma, Inc. , part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States.
authors.forename: Antitsa D
authors.initials: AD
authors.lastname: Stoycheva
authors.affiliation: Alios BioPharma, Inc. , part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States.
authors.forename: Natalia
authors.initials: N
authors.lastname: Dyatkina
authors.affiliation: Alios BioPharma, Inc. , part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States.
authors.forename: Guangyi
authors.initials: G
authors.lastname: Wang
authors.affiliation: Alios BioPharma, Inc. , part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States.
authors.forename: Julian A
authors.initials: JA
authors.lastname: Symons
authors.affiliation: Alios BioPharma, Inc. , part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States.
authors.forename: Jerome
authors.identifier: 0000-0002-0133-4673
authors.initials: J
authors.lastname: Deval
authors.affiliation: Alios BioPharma, Inc. , part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States.
authors.forename: Leo
authors.initials: L
authors.lastname: Beigelman
mesh_terms: D065767:Activation, Metabolic; D000998:Antiviral Agents / Q000378:metabolism* / Q000494:pharmacology; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D003842:Deoxycytidine Kinase / Q000378:metabolism; D055808:Drug Discovery; D006801:Humans; D010766:Phosphorylation; D011355:Prodrugs / Q000378:metabolism* / Q000494:pharmacology; D018357:Respiratory Syncytial Virus Infections / Q000188:drug therapy* / Q000378:metabolism / Q000821:virology; D012136:Respiratory Syncytial Viruses / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D011355:Prodrugs; D003841:Deoxycytidine; C000597470:4'-chloromethyl-2'-deoxy-3',5'-di-O-isobutyryl-2'-fluorocytidine; D003842:Deoxycytidine Kinase