Cinanserin is an inhibitor of the 3C-like proteinase of severe acute respiratory syndrome coronavirus and strongly reduces virus replication in vitro.
The 3C-like proteinase (3CLpro) of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is one of the most promising targets for anti-SARS-CoV drugs due to its crucial role in the viral life cycle. In this study, a database containing structural information of more than 8,000 existing drugs was virtually screened by a docking approach to identify potential binding molecules of SARS-CoV 3CLpro. As a target for screening, both a homology model and the crystallographic structure of the binding pocket of the enzyme were used. Cinanserin (SQ 10,643), a well-characterized serotonin antagonist that has undergone preliminary clinical testing in humans in the 1960s, showed a high score in the screening and was chosen for further experimental evaluation. Binding of both cinanserin and its hydrochloride to bacterially expressed 3CLpro of SARS-CoV and the related human coronavirus 229E (HCoV-229E) was demonstrated by surface plasmon resonance technology. The catalytic activity of both enzymes was inhibited with 50% inhibitory concentration (IC50) values of 5 microM, as tested with a fluorogenic substrate. The antiviral activity of cinanserin was further evaluated in tissue culture assays, namely, a replicon system based on HCoV-229E and quantitative test assays with infectious SARS-CoV and HCoV-229E. All assays revealed a strong inhibition of coronavirus replication at nontoxic drug concentrations. The level of virus RNA and infectious particles was reduced by up to 4 log units, with IC50 values ranging from 19 to 34 microM. These findings demonstrate that the old drug cinanserin is an inhibitor of SARS-CoV replication, acting most likely via inhibition of the 3CL proteinase.
Chen
Lili
L
Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.
Gui
Chunshan
C
Luo
Xiaomin
X
Yang
Qingang
Q
Günther
Stephan
S
Scandella
Elke
E
Drosten
Christian
C
Bai
Donglu
D
He
Xichang
X
Ludewig
Burkhard
B
Chen
Jing
J
Luo
Haibin
H
Yang
Yiming
Y
Yang
Yifu
Y
Zou
Jianping
J
Thiel
Volker
V
Chen
Kaixian
K
Shen
Jianhua
J
Shen
Xu
X
Jiang
Hualiang
H
D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D001483:Base Sequence; D002460:Cell Line; D002522:Chlorocebus aethiops; D002928:Cinanserin / Q000737:chemistry / Q000494:pharmacology*; D000086782:Coronavirus 3C Proteases; D006224:Cricetinae; D003546:Cysteine Endopeptidases; D004279:DNA, Viral / Q000235:genetics; D004353:Drug Evaluation, Preclinical / Q000379:methods; D010450:Endopeptidases / Q000737:chemistry / Q000235:genetics; D006801:Humans; D066298:In Vitro Techniques; D008958:Models, Molecular; D011480:Protease Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D012324:RNA-Dependent RNA Polymerase / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D045473:Severe acute respiratory syndrome-related coronavirus / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D014584:User-Computer Interface; D014709:Vero Cells; D014764:Viral Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D014779:Virus Replication / Q000187:drug effects
D000998:Antiviral Agents; D004279:DNA, Viral; D011480:Protease Inhibitors; D011994:Recombinant Proteins; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D000086782:Coronavirus 3C Proteases; D002928:Cinanserin