ABSTRACT
Upon screening synthetic small molecule libraries with the infectious hepatitis C virus (HCV) cell culture system, we identified a benzothiazepinecarboxamide (BTC) scaffold that inhibits HCV. A structure-activity relationship (SAR) study with BTCs was performed, and modifications that led to nanomolar antiviral activity and improved the selective index (CC50/EC50) by more than 1000-fold were identified. In addition, a pharmacophore modeling study determined that the tricyclic core and positive charge on the piperidine moiety were essential for antiviral activity. Furthermore, we demonstrated that BTC interferes with HCV glycoprotein E1/E2-mediated viral entry and the generation of infectious virions by using HCV pseudoparticle and cell culture supernatant transfer assays, respectively. BTC showed potent antiviral activity against HCV genotype 2 (EC50 = 0.01 ± 0.01 µM), but was less potent against a genotype 1/2 chimeric virus (EC50 = 2.71 ± 0.05 µM), which expressed the structural proteins of HCV genotype 1. In summary, we identified, optimized, and characterized novel BTC inhibitors that interfere with early and late steps of the HCV viral life cycle.
Subject(s)
Antiviral Agents/pharmacology , Drug Discovery , Hepacivirus/drug effects , Thiazepines/pharmacology , Virus Internalization/drug effects , Virus Replication/drug effects , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Cell Line , Genotype , Hepacivirus/genetics , Hepacivirus/physiology , Humans , Small Molecule Libraries/pharmacology , Structure-Activity Relationship , Thiazepines/chemical synthesis , Thiazepines/chemistry , Virion/drug effectsABSTRACT
A high-throughput (HTS) and high-content screening (HCS) campaign of a commercial library identified 2,3-dihydroimidazo[1,2-a]benzimidazole analogues as a novel class of anti-parasitic agents. A series of synthetic derivatives were evaluated for their in vitro anti-leishmanial and anti-trypanosomal activities against Leishmania donovani and Trypanosoma cruzi, which have been known as the causative parasites for visceral leishmaniasis and Chagas disease, respectively. In the case of Leishmania, the compounds were tested in both intracellular amastigote and extracellular promastigote assays. Compounds 4 and 24 showed promising anti-leishmanial activity against intracellular L. donovani (3.05 and 5.29 µM, respectively) and anti-trypanosomal activity against T. cruzi (1.10 and 2.10 µM, respectively) without serious cytotoxicity toward THP-1 and U2OS cell lines.
Subject(s)
Antiparasitic Agents/chemical synthesis , Antiparasitic Agents/pharmacology , Benzimidazoles/chemical synthesis , Benzimidazoles/pharmacology , Heterocyclic Compounds, 3-Ring/chemical synthesis , Heterocyclic Compounds, 3-Ring/pharmacology , Leishmania donovani/drug effects , Trypanosoma cruzi/drug effects , Antiparasitic Agents/chemistry , Benzimidazoles/chemistry , Cells, Cultured , Dose-Response Relationship, Drug , Heterocyclic Compounds, 3-Ring/chemistry , Humans , Molecular Structure , Parasitic Sensitivity Tests , Structure-Activity RelationshipABSTRACT
In this report we describe 2-iminobenzimidazole (IBI) analogs, identified during the course of a phenotypic high-throughput screening campaign, as novel hepatitis C virus (HCV) inhibitors. A series of IBI derivatives was synthesized and evaluated for their inhibitory activity against infectious HCV. Among the IBIs derivatives studied in this work, we identified promising compounds with high antiviral efficacy, high selectivity index and good microsomal stability. Noteworthy, the IBI series exhibited inhibitory activity on early and late steps of the viral cycle, but not in the HCV replicon system demonstrating a mechanism of action distinct from clinical-stage and approved anti-HCV drugs. Overall, our results suggest that IBIs are predestinated for further exploration as lead compounds for novel HCV interventions.
Subject(s)
Antiviral Agents/pharmacology , Benzimidazoles/pharmacology , Drug Discovery , Hepacivirus/drug effects , Imines/pharmacology , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Benzimidazoles/chemical synthesis , Benzimidazoles/chemistry , Dose-Response Relationship, Drug , Imines/chemical synthesis , Imines/chemistry , Microbial Sensitivity Tests , Molecular Structure , Structure-Activity Relationship , Virus Replication/drug effectsABSTRACT
In order to identify novel anti-hepatitis C virus (HCV) agents we devised cell-based strategies and screened phenotypically small molecule chemical libraries with infectious HCV particles, and identified a hit compound (1) containing a hexahydropyrimidine (HHP) core. During our cell-based SAR study, we observed a conversion of HHP 1 into a linear diamine (6), which is the active component in inhibiting HCV and exhibited comparable antiviral activity to the cyclic HHP 1. In addition, we engaged into the biological characterization of HHP and demonstrated that HHP does not interfere with HCV RNA replication, but with entry and release of viral particles. Here we report the results of the preliminary SAR and mechanism of action studies with HHP.
Subject(s)
Diamines/pharmacology , Hepacivirus/drug effects , Pyrimidines/pharmacology , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Diamines/chemical synthesis , Diamines/chemistry , Dose-Response Relationship, Drug , High-Throughput Screening Assays , Humans , Microbial Sensitivity Tests , Molecular Structure , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Structure-Activity Relationship , Virus Replication/drug effectsABSTRACT
We describe a novel 7-aminopyrazolo[1,5-a]pyrimidine (7-APP) derivative as a potent hepatitis C virus (HCV) inhibitor. A series of 7-APPs was synthesized and evaluated for inhibitory activity against HCV in different cell culture systems. The synthesis and preliminary structure-activity relationship study of 7-APP are reported.
Subject(s)
Antiviral Agents/pharmacology , Drug Discovery , Hepacivirus/drug effects , Pyrazoles/pharmacology , Pyrimidines/pharmacology , Animals , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Drug Stability , Humans , Microbial Sensitivity Tests , Molecular Structure , Pyrazoles/chemistry , Pyrazoles/metabolism , Pyrimidines/chemistry , Pyrimidines/metabolism , Rats , Structure-Activity RelationshipABSTRACT
We identified a novel class of aryl-substituted triazine compounds as potent non-nucleoside reverse transcriptase inhibitors (NNRTIs) during a high-throughput screening campaign that evaluated more than 200000 compounds for antihuman immunodeficiency virus (HIV) activity using a cell-based full replication assay. Herein, we disclose the optimization of the antiviral activity in a cell-based assay system leading to the discovery of compound 27, which possessed excellent potency against wild-type HIV-1 (EC50 = 0.2 nM) as well as viruses bearing Y181C and K103N resistance mutations in the reverse transcriptase gene. The X-ray crystal structure of compound 27 complexed with wild-type reverse transcriptase confirmed the mode of action of this novel class of NNRTIs. Introduction of a chloro functional group in the pyrazole moiety dramatically improved hERG and CYP inhibition profiles, yielding highly promising leads for further development.