Two novel fusion inhibitors of human respiratory syncytial virus.
To search for novel drugs against human respiratory syncytial virus (RSV), we have screened a diversity collection of 16,671 compounds for anti-RSV activity in cultures of HEp-2 cells. Two of the hit compounds, i.e., the N-(2-hydroxyethyl)-4-methoxy-N-methyl-3-(6-methyl[1,2,4]triazolo[3,4-a]phthalazin-3-yl)benzenesulfonamide (designated as P13) and the 1,4-bis(3-methyl-4-pyridinyl)-1,4-diazepane (designated as C15), reduced the virus infectivity with IC₅₀ values of 0.11 and 0.13μM respectively. The concentration of P13 and C15 that reduced the viability of HEp-2 cells by 50% was 310 and 75μM respectively. Both P13 and C15 exhibited no direct virucidal activity or inhibitory effects on the virus attachment to cells. However, to inhibit formation of RSV-induced syncytial plaques P13 and C15 had to be present during the virus entry into the cells and the cell-to-cell transmission of the virus. The RSV multiplication in HEp-2 cells in the presence of P13 or C15 resulted in rapid selection of viral variants that were ∼1000 times less sensitive to these drugs than original virus. Sequencing of resistant viruses revealed presence of amino acid substitutions in the F protein of RSV, i.e., the D489G for C15-selected, and the T400I and N197T (some clones) for the P13-selected virus variants. In conclusion, we have identified two novel fusion inhibitors of RSV, and the detailed understanding of their mode of antiviral activity including selection for the drug resistant viral variants may help to develop selective and efficient anti-RSV drugs.
Department of Clinical Virology, University of Gothenburg, Göteborg, Sweden.
Anna
A
Lundin
Tomas
T
Bergström
Loubna
L
Bendrioua
Nina
N
Kann
Beata
B
Adamiak
Edward
E
Trybala
D019943:Amino Acid Substitution / Q000187:drug effects* / Q000235:genetics; D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry* / Q000494:pharmacology* / Q000627:therapeutic use; D001381:Azepines / Q000737:chemistry* / Q000494:pharmacology* / Q000627:therapeutic use; D002460:Cell Line; D006224:Cricetinae; D004353:Drug Evaluation, Preclinical; D024882:Drug Resistance, Viral; D006801:Humans; D020128:Inhibitory Concentration 50; D008561:Membrane Fusion / Q000187:drug effects*; D010793:Phthalazines / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D011725:Pyridines / Q000737:chemistry* / Q000494:pharmacology* / Q000627:therapeutic use; D018357:Respiratory Syncytial Virus Infections / Q000188:drug therapy / Q000235:genetics*; D018113:Respiratory Syncytial Virus, Human / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development; D012641:Selection, Genetic / Q000187:drug effects*; D017421:Sequence Analysis; D013449:Sulfonamides / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D014760:Viral Fusion Proteins / Q000235:genetics* / Q000378:metabolism; D053585:Virus Attachment / Q000187:drug effects*; D000096926:Benzenesulfonamides
D000998:Antiviral Agents; D001381:Azepines; D010793:Phthalazines; D011725:Pyridines; D013449:Sulfonamides; D014760:Viral Fusion Proteins; C556122:1,4-bis(3-methyl-4-pyridinyl)-1,4-diazepane; C556118:N-(2-hydroxyethyl)-4-methoxy-N-methyl-3-(6-methyl(1,2,4)triazolo(3,4-a)phthalazin-3-yl)benzenesulfonamide; D000096926:Benzenesulfonamides