RESUMO
The COVID-19 pandemic has revealed the vulnerability of the modern, global society. With expected waves of future infections by SARS-CoV-2, treatment options for infected individuals will be crucial in order to decrease mortality and hospitalizations. The SARS-CoV-2 main protease is a validated drug target, for which the first inhibitor has been approved for use in patients. To facilitate future work on this drug target, we designed a solid-phase synthesis route towards azapeptide activity-based probes that are capped with a cysteine-reactive electrophile for covalent modification of the active site of Mpro. This design led to the most potent ABP for Mpro and one of the most potent inhibitors reported thus far. We demonstrate that this ABP can be used to visualize Mpro activity and target engagement by drugs in infected cells.
RESUMO
Massive efforts on both vaccine development and antiviral research were launched to combat the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We contributed, amongst others, by the development of a high-throughput screening (HTS) antiviral assay against SARS-CoV-2 using a fully automated, high-containment robot system. Here, we describe the development of this novel, convenient and phenotypic dual-reporter virus-cell-based high-content imaging assay using the A549+hACE2+TMPRSS2_mCherry reporter lung carcinoma cell line and an ancestral SARS-CoV-2_Wuhan_mNeonGreen reporter virus. Briefly, by means of clonal selection, a host cell subclone was selected that (i) efficiently supports replication of the reporter virus with high expression, upon infection, of the NeonGreen fluorescent reporter protein, (ii) that is not affected by virus-induced cytopathogenic effects and, (iii) that expresses a strong fluorescent mCherry signal in the nucleus. The selected clone matched these criteria with an infection rate on average of 75% with limited cell death. The average (R)Z'-factors of the assay plates were all >0.8, which indicates a robust assay suitable for HTS purposes. A selection of reference compounds that inhibits SARS-CoV-2 replication in vitro were used to validate this novel dual-reporter assay and confirms the data reported in the literature. This assay is a convenient and powerful tool for HTS of large compound libraries against SARS-CoV-2.
Assuntos
Antivirais , COVID-19 , Humanos , Antivirais/farmacologia , Antivirais/metabolismo , Ensaios de Triagem em Larga Escala/métodos , SARS-CoV-2 , Descoberta de Drogas , Replicação ViralRESUMO
SARS-CoV-2 is the causative agent behind the COVID-19 pandemic. The main protease (Mpro, 3CLpro) of SARS-CoV-2 is a key enzyme that processes polyproteins translated from the viral RNA. Mpro is therefore an attractive target for the design of inhibitors that block viral replication. We report the diastereomeric resolution of the previously designed SARS-CoV-2 Mpro α-ketoamide inhibitor 13b. The pure (S,S,S)-diastereomer, 13b-K, displays an IC50 of 120 nM against the Mpro and EC50 values of 0.8-3.4 µM for antiviral activity in different cell types. Crystal structures have been elucidated for the Mpro complexes with each of the major diastereomers, the active (S,S,S)-13b (13b-K), and the nearly inactive (R,S,S)-13b (13b-H); results for the latter reveal a novel binding mode. Pharmacokinetic studies show good levels of 13b-K after inhalative as well as after peroral administration. The active inhibitor (13b-K) is a promising candidate for further development as an antiviral treatment for COVID-19.
Assuntos
Tratamento Farmacológico da COVID-19 , SARS-CoV-2 , Humanos , Antivirais/química , Antivirais/farmacologia , Proteases 3C de Coronavírus , Cisteína Endopeptidases/metabolismo , Pandemias , Poliproteínas , Inibidores de Proteases/química , Inibidores de Proteases/farmacologia , RNA Viral , Proteínas não Estruturais Virais/metabolismoRESUMO
Analogs of pyrimidine and 1,3,4-oxadiazole are two well established class of molecules proven as potent antiviral and anticancer agents in the pharmaceutical industry. We envisioned designing new molecules where these two heterocycles were conjugated with the goal of enhancing biological activity. In this vein, we synthesized a series of novel pyrimidine-1,3,4-oxadiazole conjugated hybrid molecules as potential anticancer and antiviral agents. Herein, we present a new design for 5-fluorocytosine-1,3,4-oxadiazole hybrids (5a-h) connected via a methylene bridge. An efficient synthesis of new derivatives was established, and all compounds were fully characterized by NMR and MS. Eight compounds were evaluated for their cytotoxic activity against fibrosarcoma (HT-1080), breast (MCF-7 and MDA-MB-231), lung carcinoma (A-549), and for their antiviral activity against SARS-CoV-2. Among all compounds tested, the compound 5e showed marked growth inhibition against all cell lines tested, particularly in HT-1080, with IC50 values of 19.56 µM. Meanwhile, all tested compounds showed no anti-SARS-CoV-2 activity, with EC50 >100 µM. The mechanism of cell death was investigated using Annexin V staining, caspase-3/7 activity, and analysis of cell cycle progression. The compound 5e induced apoptosis by the activation of caspase-3/7 and cell-cycle arrest in HT-1080 and A-549 cells at the G2M phase. The molecular docking suggested that the compound 5e activated caspase-3 via the formation of a stable complex protein-ligand.
RESUMO
Drugs targeting SARS-CoV-2 could have saved millions of lives during the COVID-19 pandemic, and it is now crucial to develop inhibitors of coronavirus replication in preparation for future outbreaks. We explored two virtual screening strategies to find inhibitors of the SARS-CoV-2 main protease in ultralarge chemical libraries. First, structure-based docking was used to screen a diverse library of 235 million virtual compounds against the active site. One hundred top-ranked compounds were tested in binding and enzymatic assays. Second, a fragment discovered by crystallographic screening was optimized guided by docking of millions of elaborated molecules and experimental testing of 93 compounds. Three inhibitors were identified in the first library screen, and five of the selected fragment elaborations showed inhibitory effects. Crystal structures of target-inhibitor complexes confirmed docking predictions and guided hit-to-lead optimization, resulting in a noncovalent main protease inhibitor with nanomolar affinity, a promising in vitro pharmacokinetic profile, and broad-spectrum antiviral effect in infected cells.
Assuntos
Antivirais/farmacologia , Proteases 3C de Coronavírus/metabolismo , Inibidores de Cisteína Proteinase/farmacologia , SARS-CoV-2/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Antivirais/metabolismo , Antivirais/farmacocinética , Domínio Catalítico , Chlorocebus aethiops , Proteases 3C de Coronavírus/química , Inibidores de Cisteína Proteinase/metabolismo , Inibidores de Cisteína Proteinase/farmacocinética , Avaliação Pré-Clínica de Medicamentos , Humanos , Testes de Sensibilidade Microbiana , Microssomos Hepáticos/metabolismo , Simulação de Acoplamento Molecular , Ligação Proteica , SARS-CoV-2/enzimologia , Bibliotecas de Moléculas Pequenas/metabolismo , Bibliotecas de Moléculas Pequenas/farmacocinética , Células VeroRESUMO
We assessed the in vitro antiviral activity of remdesivir and its parent nucleoside GS-441524, molnupiravir and its parent nucleoside EIDD-1931 and the viral protease inhibitor nirmatrelvir against the ancestral SARS-CoV2 strain and the five variants of concern including Omicron. VeroE6-GFP cells were pre-treated overnight with serial dilutions of the compounds before infection. The GFP signal was determined by high-content imaging on day 4 post-infection. All molecules have equipotent antiviral activity against the ancestral virus and the VOCs Alpha, Beta, Gamma, Delta and Omicron. These findings are in line with the observation that the target proteins of these antivirals (respectively the viral RNA dependent RNA polymerase and the viral main protease Mpro) are highly conserved.
Assuntos
Monofosfato de Adenosina/análogos & derivados , Alanina/análogos & derivados , Antivirais/uso terapêutico , Tratamento Farmacológico da COVID-19 , Citidina/análogos & derivados , Hidroxilaminas/uso terapêutico , Lactamas/uso terapêutico , Leucina/uso terapêutico , Nitrilas/uso terapêutico , Prolina/uso terapêutico , SARS-CoV-2/efeitos dos fármacos , Adenosina/análogos & derivados , Adenosina/uso terapêutico , Monofosfato de Adenosina/uso terapêutico , Alanina/uso terapêutico , Animais , Linhagem Celular , Chlorocebus aethiops , Proteases 3C de Coronavírus/antagonistas & inibidores , Citidina/uso terapêutico , Humanos , Testes de Sensibilidade Microbiana , RNA Polimerase Dependente de RNA/antagonistas & inibidores , Células Vero , Replicação Viral/efeitos dos fármacosRESUMO
The Coronavirus Disease 2019 (COVID-19) and dengue fever (DF) pandemics both remain to be significant public health concerns in the foreseeable future. Anti-SARS-CoV-2 drugs and vaccines are both indispensable to eliminate the epidemic situation. Here, two piperazine-based polyphenol derivatives DF-47 and DF-51 were identified as potential inhibitors directly blocking the active site of SARS-CoV-2 and DENV RdRp. Data through RdRp inhibition screening of an in-house library and in vitro antiviral study selected DF-47 and DF-51 as effective inhibitors of SARS-CoV-2/DENV polymerase. Moreover, in silico simulation revealed stable binding modes between the DF-47/DF-51 and SARS-CoV-2/DENV RdRp, respectively, including chelating with Mg2+ near polymerase active site. This work discovered the inhibitory effect of two polyphenols on distinct viral RdRp, which are expected to be developed into broad-spectrum, non-nucleoside RdRp inhibitors with new scaffold.
Assuntos
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/metabolismo , Polifenóis/farmacologia , RNA Polimerase Dependente de RNA/metabolismo , Antivirais/química , Simulação de Acoplamento MolecularRESUMO
There are, besides remdesivir, no approved antivirals for the treatment of SARS-CoV-2 infections. To aid in the search for antivirals against this virus, we explored the use of human tracheal airway epithelial cells (HtAEC) and human small airway epithelial cells (HsAEC) grown at the air-liquid interface (ALI). These cultures were infected at the apical side with one of two different SARS-CoV-2 isolates. Each virus was shown to replicate to high titers for extended periods of time (at least 8 days) and, in particular an isolate with the D614G in the spike (S) protein did so more efficiently at 35 °C than 37 °C. The effect of a selected panel of reference drugs that were added to the culture medium at the basolateral side of the system was explored. Remdesivir, GS-441524 (the parent nucleoside of remdesivir), EIDD-1931 (the parent nucleoside of molnupiravir) and IFN (ß1 and λ1) all resulted in dose-dependent inhibition of viral RNA and infectious virus titers collected at the apical side. However, AT-511 (the free base form of AT-527 currently in clinical testing) failed to inhibit viral replication in these in vitro primary cell models. Together, these results provide a reference for further studies aimed at selecting SARS-CoV-2 inhibitors for further preclinical and clinical development.
Assuntos
Antivirais/farmacologia , Tratamento Farmacológico da COVID-19 , SARS-CoV-2/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Animais , Linhagem Celular , Chlorocebus aethiops , Avaliação Pré-Clínica de Medicamentos/métodos , Células Epiteliais/virologia , Humanos , RNA Viral , SARS-CoV-2/isolamento & purificação , Células VeroRESUMO
There is an urgent need for antivirals targeting the SARS-CoV-2 virus to fight the current COVID-19 pandemic. The SARS-CoV-2 main protease (3CLpro) represents a promising target for antiviral therapy. The lack of selectivity for some of the reported 3CLpro inhibitors, specifically versus cathepsin L, raises potential safety and efficacy concerns. ALG-097111 potently inhibited SARS-CoV-2 3CLpro (IC50 = 7 nM) without affecting the activity of human cathepsin L (IC50 > 10 µM). When ALG-097111 was dosed in hamsters challenged with SARS-CoV-2, a robust and significant 3.5 log10 (RNA copies/mg) reduction of the viral RNA copies and 3.7 log10 (TCID50/mg) reduction in the infectious virus titers in the lungs was observed. These results provide the first in vivo validation for the SARS-CoV-2 3CLpro as a promising therapeutic target for selective small molecule inhibitors.
Assuntos
Amidas/farmacologia , Tratamento Farmacológico da COVID-19 , Proteases 3C de Coronavírus/antagonistas & inibidores , Inibidores de Cisteína Proteinase/farmacologia , Modelos Animais de Doenças , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/enzimologia , Amidas/farmacocinética , Animais , COVID-19/virologia , Catepsina L/antagonistas & inibidores , Linhagem Celular , Cricetinae , Inibidores de Cisteína Proteinase/farmacocinética , Feminino , Humanos , Concentração Inibidora 50 , Masculino , Mesocricetus/virologia , Reprodutibilidade dos Testes , SARS-CoV-2/crescimento & desenvolvimento , Serina Endopeptidases , Especificidade por Substrato , Replicação Viral/efeitos dos fármacosRESUMO
Compound repurposing is an important strategy for the identification of effective treatment options against SARS-CoV-2 infection and COVID-19 disease. In this regard, SARS-CoV-2 main protease (3CL-Pro), also termed M-Pro, is an attractive drug target as it plays a central role in viral replication by processing the viral polyproteins pp1a and pp1ab at multiple distinct cleavage sites. We here report the results of a repurposing program involving 8.7 K compounds containing marketed drugs, clinical and preclinical candidates, and small molecules regarded as safe in humans. We confirmed previously reported inhibitors of 3CL-Pro and have identified 62 additional compounds with IC50 values below 1 µM and profiled their selectivity toward chymotrypsin and 3CL-Pro from the Middle East respiratory syndrome virus. A subset of eight inhibitors showed anticytopathic effect in a Vero-E6 cell line, and the compounds thioguanosine and MG-132 were analyzed for their predicted binding characteristics to SARS-CoV-2 3CL-Pro. The X-ray crystal structure of the complex of myricetin and SARS-Cov-2 3CL-Pro was solved at a resolution of 1.77 Å, showing that myricetin is covalently bound to the catalytic Cys145 and therefore inhibiting its enzymatic activity.