title: Inhibition of both protease and helicase activities of hepatitis C virus NS3 by an ethyl acetate extract of marine sponge Amphimedon sp.
abstract: Combination therapy with ribavirin, interferon, and viral protease inhibitors could be expected to elicit a high level of sustained virologic response in patients infected with hepatitis C virus (HCV). However, several severe side effects of this combination therapy have been encountered in clinical trials. In order to develop more effective and safer anti-HCV compounds, we employed the replicon systems derived from several strains of HCV to screen 84 extracts from 54 organisms that were gathered from the sea surrounding Okinawa Prefecture, Japan. The ethyl acetate-soluble extract that was prepared from marine sponge Amphimedon sp. showed the highest inhibitory effect on viral replication, with EC₅₀ values of 1.5 and 24.9 µg/ml in sub-genomic replicon cell lines derived from genotypes 1b and 2a, respectively. But the extract had no effect on interferon-inducing signaling or cytotoxicity. Treatment with the extract inhibited virus production by 30% relative to the control in the JFH1-Huh7 cell culture system. The in vitro enzymological assays revealed that treatment with the extract suppressed both helicase and protease activities of NS3 with IC₅₀ values of 18.9 and 10.9 µg/ml, respectively. Treatment with the extract of Amphimedon sp. inhibited RNA-binding ability but not ATPase activity. These results suggest that the novel compound(s) included in Amphimedon sp. can target the protease and helicase activities of HCV NS3.
authors.affiliation: Department of Microbiology, Division of Medicine, Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan.
authors.forename: Yuusuke
authors.initials: Y
authors.lastname: Fujimoto
authors.forename: Kazi Abdus
authors.initials: KA
authors.lastname: Salam
authors.forename: Atsushi
authors.initials: A
authors.lastname: Furuta
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Matsuda
authors.forename: Osamu
authors.initials: O
authors.lastname: Fujita
authors.forename: Hidenori
authors.initials: H
authors.lastname: Tani
authors.forename: Masanori
authors.initials: M
authors.lastname: Ikeda
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kato
authors.forename: Naoya
authors.initials: N
authors.lastname: Sakamoto
authors.forename: Shinya
authors.initials: S
authors.lastname: Maekawa
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Enomoto
authors.forename: Nicole J
authors.initials: NJ
authors.lastname: de Voogd
authors.forename: Masamichi
authors.initials: M
authors.lastname: Nakakoshi
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Tsubuki
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sekiguchi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsuneda
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Akimitsu
authors.forename: Naohiro
authors.initials: N
authors.lastname: Noda
authors.forename: Atsuya
authors.initials: A
authors.lastname: Yamashita
authors.forename: Junichi
authors.initials: J
authors.lastname: Tanaka
authors.forename: Kohji
authors.initials: K
authors.lastname: Moriishi
mesh_terms: D000085:Acetates; D000818:Animals; D000998:Antiviral Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D045424:Complex Mixtures / Q000737:chemistry; D016174:Hepacivirus / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D016898:Interferon-alpha / Q000378:metabolism; D011161:Porifera / Q000737:chemistry*; D011480:Protease Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors*; D014779:Virus Replication / Q000187:drug effects; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D000085:Acetates; D000998:Antiviral Agents; D045424:Complex Mixtures; D016898:Interferon-alpha; D011480:Protease Inhibitors; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C007650:ethyl acetate