Browsing by Author "Sztajer, Helena"

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    Discovery of antiviral molecules for dengue: in silico search and biological evaluation
    (2014) Cabarcas Montalvo, María; Maldonado Rojas, Wilson; Montes Grajales, Diana Lucía; Bertel Sevilla, Angela; Wagner Döbler, Irene; Sztajer, Helena; Reck, Michael; Flechas Alarcón, María Camila; Ocazionez, Raquel Elvira; Olivero Vebel, Jesús
    Background: Dengue disease is a global disease that has no effective treatment. The dengue virus (DENV) NS2B/NS3 protease complex is a target for designing specific antivirals due to its importance in viral replication and its high degree of conservation. Methods: NS2B/NS3 protease complex structural information was employed to find small molecules that can inhibit the activity of the enzyme complex. This inhibitory activity was probed with in vitro assays using a fluorescent substrateand the complex NS2B/NS3 obtained by recombinant DNA techniques, for testing the activity against dengue virus replication, HepG2 cells infected with dengue virus serotype 2 were used. Results: A total of 210,903 small molecules from PubChem were docked in silico to the NS2B/NS3 structure (PDB: 2FOM) to find molecules that could inhibit this protein complex. Five of the best 500 leading compounds, according to their affinity values (-11.6 and -13.5 kcal/mol), were purchased. The inhibitory protease activity on the recombinant protein and antiviral assays was tested. Conclusions: Chemicals CID54681617, CID54692801 and CID54715399 were strong inhibitors of NS2B/NS3, with IC50 values (μM) and percentages of viral titer reductions of 19.9, 79.9%; 17.5, 69.8%; and 9.1, 73.9 %, respectively. Multivariate methods applied to the molecular descriptors showed two compounds that were structurally different from other DENV inhibitors. General significance: This discovery opens new possibilities for obtaining drug candidates against Dengue virus.
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    Novel NS2B/NS3-protease dengue virus inhibitors
    (2014) Cabarcas Montalvo, María; Olivero Vebel, Jesús; Montes Grajales, Diana Lucía; Maldonado Rojas, Wilson; Bertel Sevilla, Angela; Wagner Döbler, Irene; Sztajer, Helena; Reck, Michael; Flechas Alarcón, María Camila; Ocazionez, Raquel Elvira
    Dengue disease, caused by the virus of the same name, is expanding globally with an annual estimate of 390 million people infected. However, available antivirals have been ineffective. Therefore, the search of small-molecule therapeutic candidates is a recurrent practice. The dengue virus (DENV) NS2B/NS3 protease complex is a recognized target for the design of specific antivirals, due to its importance in the replication and high degree of sequence conservation. The aim of this research was to find molecules capable of inhibiting this protein complex. A total of 210,903 molecules, from the PubChem database, were docked in silico to the NS2B/NS3 crystallographic structure (PDB: 2FOM). The recombinant protease was expressed in E. coli and purified by affinity chromatography. Five of the best 500 leading compounds, according to the virtual screening affinity values (-11.6 and -13.5 kcal/mol), were purchased. The inhibitory activity of these molecules by the protease was evaluated in vitro, using the action of the recombinant enzyme on the Boc-Gly-Arg-Arg-AMC substrate (IC50), and antiviral assays for the detection of NS1 viral titles in infected human hepatocytes. Compounds CID54681617, CID54692801, and CID54715399 showed to be strong inhibitors of NS2B/NS3, with IC50 values (μM) and percentages of NS1 viral title reductions corresponding to 19.9, 79.9%; 17.5, 69.8%; 9.1, 73.9 %, respectively. Multivariate methods on molecular descriptors showed that two of these compounds are structurally different from DENV inhibitors reported by other authors. This discovery opens new possibilities to obtain drug candidates against Dengue.