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Novel Broad Spectrum Inhibitors Targeting the Flavivirus Methyltransferase.

Brecher M, Chen H, Liu B, Banavali NK, Jones SA, Zhang J, Li Z, Kramer LD, Li H - PLoS ONE (2015)

Bottom Line: The flavivirus methyltransferase (MTase) is an essential enzyme that sequentially methylates the N7 and 2'-O positions of the viral RNA cap, using S-adenosyl-L-methionine (SAM) as a methyl donor.In vitro methylation experiments demonstrated significant MTase inhibition by 13 of these compounds, with the most potent compound displaying sub-micromolar inhibitory activity.The most active compounds showed broad spectrum activity against the MTase proteins of multiple flaviviruses.

View Article: PubMed Central - PubMed

Affiliation: Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY, 12208 United States of America.

ABSTRACT
The flavivirus methyltransferase (MTase) is an essential enzyme that sequentially methylates the N7 and 2'-O positions of the viral RNA cap, using S-adenosyl-L-methionine (SAM) as a methyl donor. We report here that small molecule compounds, which putatively bind to the SAM-binding site of flavivirus MTase and inhibit its function, were identified by using virtual screening. In vitro methylation experiments demonstrated significant MTase inhibition by 13 of these compounds, with the most potent compound displaying sub-micromolar inhibitory activity. The most active compounds showed broad spectrum activity against the MTase proteins of multiple flaviviruses. Two of these compounds also exhibited low cytotoxicity and effectively inhibited viral replication in cell-based assays, providing further structural insight into flavivirus MTase inhibition.

No MeSH data available.


Related in: MedlinePlus

Cytotoxicity and antiviral analyses for compounds NSC 306711 and 610930.(A & B) Cytotoxicity of NSC 306711 (A) and 610930 (B). BHK-21 cells were incubated with various concentrations of the compound and then assayed for viability at 42 hours post-incubation. (C & D) Inhibition of viral replication by NSC 306711 (C) and 610930 (D). BHK cells were infected with WNV at a multiplicity of infection of 0.1, in the presence or absence of compounds. At 42 hours post-infection, viral titers in culture fluids were quantified by plaque assays on Vero cells. Each reaction was carried out in triplicate and the standard deviation is plotted.
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pone.0130062.g005: Cytotoxicity and antiviral analyses for compounds NSC 306711 and 610930.(A & B) Cytotoxicity of NSC 306711 (A) and 610930 (B). BHK-21 cells were incubated with various concentrations of the compound and then assayed for viability at 42 hours post-incubation. (C & D) Inhibition of viral replication by NSC 306711 (C) and 610930 (D). BHK cells were infected with WNV at a multiplicity of infection of 0.1, in the presence or absence of compounds. At 42 hours post-infection, viral titers in culture fluids were quantified by plaque assays on Vero cells. Each reaction was carried out in triplicate and the standard deviation is plotted.

Mentions: Cell-based assays were next performed to evaluate the biological activities of the selected compounds. The cytotoxicity of these compounds was first evaluated by using a MTT cell proliferation assay with a BHK-21 cell line (Table 1, fig 5), as we described previously [20, 30]. As shown in fig 5 and Table 1, several compounds were quite toxic to the cells with the CC50 values similar or less than their in vitro IC50 values. The rest of the compounds, including NSC 36806, 322921, 306711, and 610930, showed much less toxicity, with CC50 values nearly 10 times higher than those of IC50 values. Therefore, these compounds were further investigated for their in vitro antiviral efficacy.


Novel Broad Spectrum Inhibitors Targeting the Flavivirus Methyltransferase.

Brecher M, Chen H, Liu B, Banavali NK, Jones SA, Zhang J, Li Z, Kramer LD, Li H - PLoS ONE (2015)

Cytotoxicity and antiviral analyses for compounds NSC 306711 and 610930.(A & B) Cytotoxicity of NSC 306711 (A) and 610930 (B). BHK-21 cells were incubated with various concentrations of the compound and then assayed for viability at 42 hours post-incubation. (C & D) Inhibition of viral replication by NSC 306711 (C) and 610930 (D). BHK cells were infected with WNV at a multiplicity of infection of 0.1, in the presence or absence of compounds. At 42 hours post-infection, viral titers in culture fluids were quantified by plaque assays on Vero cells. Each reaction was carried out in triplicate and the standard deviation is plotted.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4476580&req=5

pone.0130062.g005: Cytotoxicity and antiviral analyses for compounds NSC 306711 and 610930.(A & B) Cytotoxicity of NSC 306711 (A) and 610930 (B). BHK-21 cells were incubated with various concentrations of the compound and then assayed for viability at 42 hours post-incubation. (C & D) Inhibition of viral replication by NSC 306711 (C) and 610930 (D). BHK cells were infected with WNV at a multiplicity of infection of 0.1, in the presence or absence of compounds. At 42 hours post-infection, viral titers in culture fluids were quantified by plaque assays on Vero cells. Each reaction was carried out in triplicate and the standard deviation is plotted.
Mentions: Cell-based assays were next performed to evaluate the biological activities of the selected compounds. The cytotoxicity of these compounds was first evaluated by using a MTT cell proliferation assay with a BHK-21 cell line (Table 1, fig 5), as we described previously [20, 30]. As shown in fig 5 and Table 1, several compounds were quite toxic to the cells with the CC50 values similar or less than their in vitro IC50 values. The rest of the compounds, including NSC 36806, 322921, 306711, and 610930, showed much less toxicity, with CC50 values nearly 10 times higher than those of IC50 values. Therefore, these compounds were further investigated for their in vitro antiviral efficacy.

Bottom Line: The flavivirus methyltransferase (MTase) is an essential enzyme that sequentially methylates the N7 and 2'-O positions of the viral RNA cap, using S-adenosyl-L-methionine (SAM) as a methyl donor.In vitro methylation experiments demonstrated significant MTase inhibition by 13 of these compounds, with the most potent compound displaying sub-micromolar inhibitory activity.The most active compounds showed broad spectrum activity against the MTase proteins of multiple flaviviruses.

View Article: PubMed Central - PubMed

Affiliation: Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY, 12208 United States of America.

ABSTRACT
The flavivirus methyltransferase (MTase) is an essential enzyme that sequentially methylates the N7 and 2'-O positions of the viral RNA cap, using S-adenosyl-L-methionine (SAM) as a methyl donor. We report here that small molecule compounds, which putatively bind to the SAM-binding site of flavivirus MTase and inhibit its function, were identified by using virtual screening. In vitro methylation experiments demonstrated significant MTase inhibition by 13 of these compounds, with the most potent compound displaying sub-micromolar inhibitory activity. The most active compounds showed broad spectrum activity against the MTase proteins of multiple flaviviruses. Two of these compounds also exhibited low cytotoxicity and effectively inhibited viral replication in cell-based assays, providing further structural insight into flavivirus MTase inhibition.

No MeSH data available.


Related in: MedlinePlus