title: Amodiaquine, an antimalarial drug, inhibits dengue virus type 2 replication and infectivity.
abstract: Dengue virus serotypes 1-4 (DENV1-4) are transmitted by mosquitoes which cause most frequent arboviral infections in the world resulting in ∼390 million cases with ∼25,000 deaths annually. There is no vaccine or antiviral drug currently available for human use. Compounds containing quinoline scaffold were shown to inhibit flavivirus NS2B-NS3 protease (NS2B-NS3pro) with good potencies. In this study, we screened quinoline derivatives, which are known antimalarial drugs for inhibition of DENV2 and West Nile virus (WNV) replication using the corresponding replicon expressing cell-based assays. Amodiaquine (AQ), one of the 4-aminoquinoline drugs, inhibited DENV2 infectivity measured by plaque assays, with EC50 and EC90 values of 1.08±0.09μM and 2.69±0.47 μM, respectively, and DENV2 RNA replication measured by Renilla luciferase reporter assay, with EC50 value of 7.41±1.09μM in the replicon expressing cells. Cytotoxic concentration (CC50) in BHK-21 cells was 52.09±4.25μM. The replication inhibition was confirmed by plaque assay of the extracellular virions as well as by qRT-PCR of the intracellular and extracellular viral RNA levels. AQ was stable for at least 96h and had minor inhibitory effect on entry, translation, and post-replication stages in the viral life cycle. DENV protease, 5'-methyltransferase, and RNA-dependent RNA polymerase do not seem to be targets of AQ. Both p-hydroxyanilino and diethylaminomethyl moieties are important for AQ to inhibit DENV2 replication and infectivity. Our results support AQ as a promising candidate for anti-flaviviral therapy.
authors.affiliation: Department of Microbiology & Immunology, Georgetown University, USA. Electronic address: sb563@georgetown.edu.
authors.forename: Siwaporn
authors.initials: S
authors.lastname: Boonyasuppayakorn
authors.affiliation: Department of Microbiology & Immunology, Georgetown University, USA. Electronic address: erin.reichert@dtra.mil.
authors.forename: Erin D
authors.initials: ED
authors.lastname: Reichert
authors.affiliation: Department of Microbiology & Immunology, Georgetown University, USA. Electronic address: mark.manzano@northwestern.edu.
authors.forename: Mark
authors.initials: M
authors.lastname: Manzano
authors.affiliation: Alkem Laboratories Ltd, Bangalore 560 076, India.
authors.forename: Kuppuswamy
authors.initials: K
authors.lastname: Nagarajan
authors.affiliation: Department of Microbiology & Immunology, Georgetown University, USA. Electronic address: rp55@georgetown.edu.
authors.forename: Radhakrishnan
authors.initials: R
authors.lastname: Padmanabhan
mesh_terms: D000655:Amodiaquine / Q000494:pharmacology* / Q000633:toxicity; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology* / Q000633:toxicity; D000998:Antiviral Agents / Q000494:pharmacology* / Q000633:toxicity; D002470:Cell Survival / Q000187:drug effects; D006224:Cricetinae; D003716:Dengue Virus / Q000187:drug effects* / Q000502:physiology*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006801:Humans; D008826:Microbial Sensitivity Tests; D010948:Viral Plaque Assay; D014779:Virus Replication / Q000187:drug effects*; D014902:West Nile virus / Q000187:drug effects / Q000502:physiology
chemical_list: D000962:Antimalarials; D000998:Antiviral Agents; D000655:Amodiaquine
keywords: Amodiaquine therapeutic index; Chloroquine; Inhibition of dengue virus replication and infectivity; Primaquine; Repurposing antimalarials as dengue antivirals; Stable replicon cell lines for dengue and West Nile viruses