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1.
J Med Virol ; 94(4): 1373-1390, 2022 04.
Article in English | MEDLINE | ID: covidwho-1568201

ABSTRACT

In this era, broad-spectrum prodrugs with anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) activities are gaining considerable attention owing to their potential clinical benefits and role in combating the fast-spreading coronavirus disease 2019 (COVID-19) pandemic. The last 2 years have seen a surge of reports on various broad-spectrum prodrugs against SARS-CoV-2, and in in vitro studies, animal models, and clinical practice. Currently, only remdesivir (with many controversies and limitations) has been approved by the U.S. FDA for the treatment of SARS-CoV-2 infection, and additional potent anti-SARS-CoV-2 drugs are urgently required to enrich the defense arsenals. The world has ubiquitously grappled with the COVID-19 pandemic, and the availability of broad-spectrum prodrugs provides great hope for us to subdue this global threat. This article reviews promising treatment strategies, antiviral mechanisms, potential benefits, and daunting clinical challenges of anti-SARS-CoV-2 agents to provide some important guidance for future clinical treatment.


Subject(s)
Antiviral Agents/pharmacology , Prodrugs/pharmacology , SARS-CoV-2/drug effects , Animals , Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Anti-Infective Agents/therapeutic use , Antiviral Agents/chemistry , Antiviral Agents/therapeutic use , COVID-19/drug therapy , COVID-19/epidemiology , Humans , Prodrugs/chemistry , Prodrugs/therapeutic use , SARS-CoV-2/metabolism , Viral Proteins/antagonists & inhibitors
2.
Nat Commun ; 12(1): 6415, 2021 11 05.
Article in English | MEDLINE | ID: covidwho-1503781

ABSTRACT

Remdesivir is an antiviral approved for COVID-19 treatment, but its wider use is limited by intravenous delivery. An orally bioavailable remdesivir analog may boost therapeutic benefit by facilitating early administration to non-hospitalized patients. This study characterizes the anti-SARS-CoV-2 efficacy of GS-621763, an oral prodrug of remdesivir parent nucleoside GS-441524. Both GS-621763 and GS-441524 inhibit SARS-CoV-2, including variants of concern (VOC) in cell culture and human airway epithelium organoids. Oral GS-621763 is efficiently converted to plasma metabolite GS-441524, and in lungs to the triphosphate metabolite identical to that generated by remdesivir, demonstrating a consistent mechanism of activity. Twice-daily oral administration of 10 mg/kg GS-621763 reduces SARS-CoV-2 burden to near-undetectable levels in ferrets. When dosed therapeutically against VOC P.1 gamma γ, oral GS-621763 blocks virus replication and prevents transmission to untreated contact animals. These results demonstrate therapeutic efficacy of a much-needed orally bioavailable analog of remdesivir in a relevant animal model of SARS-CoV-2 infection.


Subject(s)
Adenosine/analogs & derivatives , Antiviral Agents/pharmacology , COVID-19/drug therapy , Prodrugs/pharmacology , SARS-CoV-2/drug effects , Adenosine/pharmacology , Animals , COVID-19/metabolism , COVID-19/virology , Cell Line , Chlorocebus aethiops , Cricetinae , Disease Models, Animal , Female , Ferrets , Humans , SARS-CoV-2/isolation & purification
3.
Bioorg Med Chem ; 46: 116364, 2021 09 15.
Article in English | MEDLINE | ID: covidwho-1406212

ABSTRACT

The nucleoside metabolite of remdesivir, GS-441524 displays potent anti-SARS-CoV-2 efficacy, and is being evaluated in clinical as an oral antiviral therapeutic for COVID-19. However, this nucleoside has a poor oral bioavailability in non-human primates, which may affect its therapeutic efficacy. Herein, we reported a variety of GS-441524 analogs with modifications on the base or the sugar moiety, as well as some prodrug forms, including five isobutyryl esters, two l-valine esters, and one carbamate. Among the new nucleosides, only the 7-fluoro analog 3c had moderate anti-SARS-CoV-2 activity, and its phosphoramidate prodrug 7 exhibited reduced activity in Vero E6 cells. As for the prodrugs, the 3'-isobutyryl ester 5a, the 5'-isobutyryl ester 5c, and the tri-isobutyryl ester 5g hydrobromide showed excellent oral bioavailabilities (F = 71.6%, 86.6% and 98.7%, respectively) in mice, which provided good insight into the pharmacokinetic optimization of GS-441524.


Subject(s)
Adenosine/analogs & derivatives , Antiviral Agents/pharmacology , SARS-CoV-2/drug effects , Adenosine/pharmacokinetics , Adenosine/pharmacology , Adenosine/toxicity , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/pharmacokinetics , Antiviral Agents/toxicity , Chlorocebus aethiops , Male , Mice, Inbred ICR , Microbial Sensitivity Tests , Prodrugs/chemical synthesis , Prodrugs/pharmacokinetics , Prodrugs/pharmacology , Prodrugs/toxicity , Vero Cells
4.
Arch Pharm (Weinheim) ; 354(11): e2100160, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1370365

ABSTRACT

Boswellic acids (BAs) have been shown to possess antiviral activity. Using bioinformatic methods, it was tested whether or not acetyl-11-keto-ß-boswellic acid (AKBA), 11-keto-ß-boswellic acid (KBA), ß-boswellic acid (BBA), and the phosphorylated active metabolite of Remdesivir® (RGS-P3) bind to functional proteins of SARS-CoV-2, that is, the replicase polyprotein P0DTD1, the spike glycoprotein P0DTC2, and the nucleoprotein P0DTC9. Using P0DTD1, AKBA and KBA showed micromolar binding affinity to the RNA-dependent RNA polymerase (RdRp) and to the main proteinase complex Mpro . Phosphorylated BAs even bond in the nanomolar range. Due to their positive and negative charges, BAs and RGS-P3 bond to corresponding negative and positive areas of the protein. BAs and RGS-P3 docked in the tunnel-like cavity of RdRp. BAs also docked into the elongated surface rim of viral Mpro . In both cases, binding occurred with active site amino acids in the lower micromolecular to upper nanomolar range. KBA, BBA, and RGS-P3 also bond to P0DTC2 and P0DTC9. The binding energies for BAs were in the range of -5.8 to -6.3 kcal/mol. RGS-P3 and BAs occluded the centrally located pore of the donut-like protein structure of P0DTC9 and, in the case of P0DTC2, RGS-P3 and BAs impacted the double-wing-like protein structure. The data of this bioinformatics study clearly show that BAs bind to three functional proteins of the SARS-CoV-2 virus responsible for adhesion and replication, as does RGS-P3, a drug on the market to treat this disease. The binding effectiveness of BAs can be increased through phosphate esterification. Whether or not BAs are druggable against the SARS-CoV-2 disease remains to be established.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , COVID-19 , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/physiology , Triterpenes/pharmacology , Viral Proteins/physiology , Adenosine Monophosphate/pharmacology , Alanine/pharmacology , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Antiviral Agents/pharmacology , Binding Sites/physiology , Boswellia , COVID-19/drug therapy , COVID-19/virology , Computational Biology/methods , Humans , Molecular Docking Simulation , Nucleoproteins/metabolism , Polyproteins/metabolism , Prodrugs/pharmacology , Protein Binding/physiology , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Structure-Activity Relationship
5.
Curr Top Med Chem ; 21(32): 2909-2927, 2021.
Article in English | MEDLINE | ID: covidwho-1332065

ABSTRACT

Synthetic nucleoside or nucleotide analogues played a key role to the development of antiviral agents in past decades. However, low membrane permeability and insufficient cellular phosphorylation impaired the biological activity of polar nucleoside drugs because they have to penetrate the cell membrane and be phosphorylated to active metabolite stepwise by intracellular enzymes. To overcome these limitations, diverse lipophilic prodrug modifications based on nucleoside mono-, di-, and triphosphate were designed and put into practice to efficiently deliver nucleoside into the target site, and bypass the rate-limited phosphorylation step. As the most successful prodrug strategy, ProTide technology has led to the discovery of three FDA-approved antiviral agents, including sofosbuvir, tenofovir alafenadmide, and remdesivir, which has been authorized for emergency use in patients of COVID-19 in the US. In recent years, nucleoside di- and triphosphate prodrugs have also made the significant progress. This review will focus on the summary of design approach and metabolic activation path of different nucleotide prodrug strategies. The potential application of nucleotide prodrugs for the treatment of COVID-19 was also described due to the pandemic of SARS-CoV-2.


Subject(s)
Antiviral Agents , Drug Design , Nucleosides , Nucleotides , Prodrugs , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Humans , Nucleosides/pharmacology , Nucleosides/therapeutic use , Nucleotides/pharmacology , Nucleotides/therapeutic use , Prodrugs/pharmacology , Prodrugs/therapeutic use , SARS-CoV-2/drug effects
6.
Neurobiol Dis ; 156: 105422, 2021 08.
Article in English | MEDLINE | ID: covidwho-1267874

ABSTRACT

Synthetic glucocorticoids (sGCs) such as dexamethasone (DEX), while used to mitigate inflammation and disease progression in premature infants with severe bronchopulmonary dysplasia (BPD), are also associated with significant adverse neurologic effects such as reductions in myelination and abnormalities in neuroanatomical development. Ciclesonide (CIC) is a sGC prodrug approved for asthma treatment that exhibits limited systemic side effects. Carboxylesterases enriched in the lower airways convert CIC to the glucocorticoid receptor (GR) agonist des-CIC. We therefore examined whether CIC would likewise activate GR in neonatal lung but have limited adverse extra-pulmonary effects, particularly in the developing brain. Neonatal rats were administered subcutaneous injections of CIC, DEX or vehicle from postnatal days 1-5 (PND1-PND5). Systemic effects linked to DEX exposure, including reduced body and brain weight, were not observed in CIC treated neonates. Furthermore, CIC did not trigger the long-lasting reduction in myelin basic protein expression in the cerebral cortex nor cerebellar size caused by neonatal DEX exposure. Conversely, DEX and CIC were both effective at inducing the expression of select GR target genes in neonatal lung, including those implicated in lung-protective and anti-inflammatory effects. Thus, CIC is a promising, novel candidate drug to treat or prevent BPD in neonates given its activation of GR in neonatal lung and limited adverse neurodevelopmental effects. Furthermore, since sGCs such as DEX administered to pregnant women in pre-term labor can adversely affect fetal brain development, the neurological-sparing properties of CIC, make it an attractive alternative for DEX to treat pregnant women severely ill with respiratory illness, such as with asthma exacerbations or COVID-19 infections.


Subject(s)
Cerebellum/drug effects , Cerebral Cortex/drug effects , Glucocorticoids , Lung/drug effects , Pregnenediones/pharmacology , Prodrugs/pharmacology , Signal Transduction/drug effects , Animals , Animals, Newborn , Anti-Inflammatory Agents/pharmacology , Body Weight/drug effects , Brain/drug effects , Brain/growth & development , COVID-19/drug therapy , Dexamethasone/pharmacology , Female , Mice , Mice, Inbred C57BL , Myelin Basic Protein/biosynthesis , Organ Size/drug effects , Pregnancy , Rats , Rats, Sprague-Dawley , Receptors, Glucocorticoid/drug effects
7.
Curr Opin Virol ; 49: 81-85, 2021 08.
Article in English | MEDLINE | ID: covidwho-1225185

ABSTRACT

The nucleotide analogue prodrug remdesivir remains the only FDA-approved antiviral small molecule for the treatment of infection with SARS-CoV-2. Biochemical studies revealed that the active form of the drug targets the viral RNA-dependent RNA polymerase and causes delayed chain-termination. Delayed chain-termination is incomplete, but the continuation of RNA synthesis enables a partial escape from viral proofreading. Remdesivir becomes embedded in the copy of the RNA genome that later serves as a template. Incorporation of an incoming nucleotide triphosphate is now inhibited by the modified template. Knowledge on the mechanism of action matters. Enzymatic inhibition links to antiviral effects in cell cultures, animal models and viral load reduction in patients, which provides the logical chain that is expected for a direct acting antiviral. Hence, remdesivir also serves as a benchmark in current drug development efforts that will hopefully lead to orally available treatments to the benefit of a broader population.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Adenosine Monophosphate/pharmacology , Adenosine Monophosphate/therapeutic use , Alanine/pharmacology , Alanine/therapeutic use , Coronavirus RNA-Dependent RNA Polymerase/antagonists & inhibitors , Coronavirus RNA-Dependent RNA Polymerase/metabolism , Humans , Prodrugs/pharmacology , Prodrugs/therapeutic use , RNA, Viral/biosynthesis , RNA, Viral/drug effects , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , SARS-CoV-2/physiology , Substrate Specificity , Virus Replication/drug effects
8.
J Med Chem ; 64(8): 5001-5017, 2021 04 22.
Article in English | MEDLINE | ID: covidwho-1174625

ABSTRACT

A discovery program targeting respiratory syncytial virus (RSV) identified C-nucleoside 4 (RSV A2 EC50 = 530 nM) as a phenotypic screening lead targeting the RSV RNA-dependent RNA polymerase (RdRp). Prodrug exploration resulted in the discovery of remdesivir (1, GS-5734) that is >30-fold more potent than 4 against RSV in HEp-2 and NHBE cells. Metabolism studies in vitro confirmed the rapid formation of the active triphosphate metabolite, 1-NTP, and in vivo studies in cynomolgus and African Green monkeys demonstrated a >10-fold higher lung tissue concentration of 1-NTP following molar normalized IV dosing of 1 compared to that of 4. A once daily 10 mg/kg IV administration of 1 in an African Green monkey RSV model demonstrated a >2-log10 reduction in the peak lung viral load. These early data following the discovery of 1 supported its potential as a novel treatment for RSV prior to its development for Ebola and approval for COVID-19 treatment.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , Prodrugs/pharmacology , Respiratory Syncytial Virus Infections/drug therapy , Respiratory Syncytial Virus, Human/drug effects , Adenosine Monophosphate/pharmacology , Alanine/pharmacology , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , Caco-2 Cells , Cells, Cultured , Chlorocebus aethiops , Disease Models, Animal , Dogs , Drug Evaluation, Preclinical/methods , Epithelial Cells/virology , Humans , Macaca fascicularis , Male , Prodrugs/chemistry , Prodrugs/pharmacokinetics , Rats, Sprague-Dawley , Respiratory Syncytial Virus Infections/virology , Structure-Activity Relationship , Tissue Distribution , Tubercidin/analogs & derivatives , Tubercidin/chemistry , Viral Load
9.
Antimicrob Agents Chemother ; 65(4)2021 03 18.
Article in English | MEDLINE | ID: covidwho-1159599

ABSTRACT

The impact of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of COVID-19, is global and unprecedented. Although remdesivir has recently been approved by the FDA to treat SARS-CoV-2 infection, no oral antiviral is available for outpatient treatment. AT-527, an orally administered double prodrug of a guanosine nucleotide analog, was previously shown to be highly efficacious and well tolerated in hepatitis C virus (HCV)-infected subjects. Here, we report the potent in vitro activity of AT-511, the free base of AT-527, against several coronaviruses, including SARS-CoV-2. In normal human airway epithelial cells, the concentration of AT-511 required to inhibit replication of SARS-CoV-2 by 90% (EC90) was 0.47 µM, very similar to its EC90 against human coronavirus (HCoV)-229E, HCoV-OC43, and SARS-CoV in Huh-7 cells. Little to no cytotoxicity was observed for AT-511 at concentrations up to 100 µM. Substantial levels of the active triphosphate metabolite AT-9010 were formed in normal human bronchial and nasal epithelial cells incubated with 10 µM AT-511 (698 ± 15 and 236 ± 14 µM, respectively), with a half-life of at least 38 h. Results from steady-state pharmacokinetic and tissue distribution studies of nonhuman primates administered oral doses of AT-527, as well as pharmacokinetic data from subjects given daily oral doses of AT-527, predict that twice daily oral doses of 550 mg AT-527 will produce AT-9010 trough concentrations in human lung that exceed the EC90 observed for the prodrug against SARS-CoV-2 replication. This suggests that AT-527 may be an effective treatment option for COVID-19.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Guanosine Monophosphate/analogs & derivatives , Guanosine/pharmacology , Phosphoramides/pharmacology , Prodrugs/pharmacology , SARS-CoV-2/drug effects , Administration, Oral , Animals , COVID-19/virology , Cell Line , Cell Line, Tumor , Chlorocebus aethiops , Coronavirus 229E, Human/metabolism , Coronavirus OC43, Human/metabolism , Cricetinae , Epithelial Cells/virology , Guanosine Monophosphate/pharmacology , Humans , Lung/virology , SARS-CoV-2/metabolism , Vero Cells , Virus Replication/drug effects
10.
Int J Pharm ; 597: 120329, 2021 Mar 15.
Article in English | MEDLINE | ID: covidwho-1152404

ABSTRACT

There has been a growing and evolving research to find a treatment or a prevention against coronavirus 2019 (COVID-19). Though mass vaccination will certainly help in reducing number of COVID-19 patients, an effective therapeutic measure must be available too. Intravenous remdesivir (RDV) was the first drug receiving Food and Drug Administration (FDA) approval for the treatment of COVID-19. However, in a pandemic like COVID-19, it is essential that drug formulations are readily available, affordable and convenient to administer to every patient around the globe. In this study, we have developed a Self-injectable extended release subcutaneous injection of Remdesivir (SelfExRem) for the treatment of COVID-19. As opposed to intravenous injection, extended release subcutaneous injection has the benefits of reducing face-to-face contact, minimizing hospitalization, reducing dosing frequency and reducing overall health care cost. SelfExRem was developed using a biodegradable polymer, poly(lactic-co-glycolic acid) (PLGA), dissolved in a biocompatible vehicle. Six different batches were formulated using 2 different grades of low molecular weight PLGA and 3 different PLGA concentration. The force of injection of various polymeric solutions through 23-30-gauge needles were analyzed using a TA.XTplus texture analyzer. The time required for injection was evaluated both manually and by using an autoinjector. In vitro release of all the batches were carried out in 1% v/v tween 80 in phosphate buffer saline. The study indicated that SelfExRem developed with15% w/v PLGA(75:25) provided a steady release of drug for 48 h and may be a breakthrough approach for the treatment of COVID-19.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , COVID-19 , Delayed-Action Preparations/pharmacology , Adenosine Monophosphate/pharmacology , Alanine/pharmacology , Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/epidemiology , COVID-19/prevention & control , Drug Evaluation, Preclinical , Humans , Injections, Subcutaneous/methods , Prodrugs/pharmacology , SARS-CoV-2
11.
Molecules ; 26(5)2021 Mar 09.
Article in English | MEDLINE | ID: covidwho-1143539

ABSTRACT

A series of hitherto unknown (1,4-disubstituted-1,2,3-triazol)-(E)-2-methyl-but-2-enyl nucleosides phosphonate prodrugs bearing 4-substituted-1,2,3-triazoles were prepared in a straight approach through an olefin acyclic cross metathesis as the key synthetic step. All novel compounds were evaluated for their antiviral activities against HBV, HIV and SARS-CoV-2. Among these molecules, only compound 15j, a hexadecyloxypropyl (HDP)/(isopropyloxycarbonyl-oxymethyl)-ester (POC) prodrug, showed activity against HBV in Huh7 cell cultures with 62% inhibition at 10 µM, without significant cytotoxicity (IC50 = 66.4 µM in HepG2 cells, IC50 = 43.1 µM in HepG2 cells) at 10 µM.


Subject(s)
Antiviral Agents/chemical synthesis , Antiviral Agents/pharmacology , Azo Compounds/chemistry , Nucleosides/chemistry , Organophosphonates/chemistry , Prodrugs/chemical synthesis , Prodrugs/pharmacology , Alkenes/chemistry , Animals , Cell Line, Tumor , Chlorocebus aethiops , HIV-1/drug effects , Hepatitis B virus/drug effects , Humans , Magnetic Resonance Spectroscopy , Methylation , SARS-CoV-2/drug effects , Structure-Activity Relationship , Triazoles/chemistry , Vero Cells
12.
Emerg Microbes Infect ; 10(1): 481-492, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1124537

ABSTRACT

The unprecedented coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a serious threat to global public health. Development of effective therapies against SARS-CoV-2 is urgently needed. Here, we evaluated the antiviral activity of a remdesivir parent nucleotide analog, GS441524, which targets the coronavirus RNA-dependent RNA polymerase enzyme, and a feline coronavirus prodrug, GC376, which targets its main protease, using a mouse-adapted SARS-CoV-2 infected mouse model. Our results showed that GS441524 effectively blocked the proliferation of SARS-CoV-2 in the mouse upper and lower respiratory tracts via combined intranasal (i.n.) and intramuscular (i.m.) treatment. However, the ability of high-dose GC376 (i.m. or i.n. and i.m.) was weaker than GS441524. Notably, low-dose combined application of GS441524 with GC376 could effectively protect mice against SARS-CoV-2 infection via i.n. or i.n. and i.m. treatment. Moreover, we found that the pharmacokinetic properties of GS441524 is better than GC376, and combined application of GC376 and GS441524 had a synergistic effect. Our findings support the further evaluation of the combined application of GC376 and GS441524 in future clinical studies.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Coronavirus RNA-Dependent RNA Polymerase/antagonists & inhibitors , Respiratory System/virology , SARS-CoV-2/drug effects , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , Cell Proliferation/drug effects , Chlorocebus aethiops , Drug Therapy, Combination , Female , Mice , Mice, Inbred BALB C , Prodrugs/pharmacology , Rats , Rats, Sprague-Dawley , Vero Cells
13.
J Pharm Biomed Anal ; 194: 113806, 2021 Feb 05.
Article in English | MEDLINE | ID: covidwho-1065380

ABSTRACT

Remdesivir is a prodrug of the nucleotide analogue and used for COVID-19 treatment. However, the bioanalysis of the active metabolites remdesivir nucleotide triphosphate (RTP) and its precursor remdesivir nucleotide monophosphate (RMP) is very challenging. Herein, we established a novel method to separate RTP and RMP on a BioBasic AX column and quantified them by high-performance liquid chromatography-tandem mass spectrometry in positive electrospray ionization mode. Stepwise, we optimized chromatographic retention on an anion exchange column, improved stability in matrix through the addition of 5,5'-dithiobis-(2nitrobenzoic acid) and PhosSTOP EASYpack, and increased recovery by dissociation of tight protein binding with 2 % formic acid aqueous solution. The method allowed lower limit of quantification of 20 nM for RMP and 10 nM for RTP. Method validation demonstrated acceptable accuracy (93.6%-103% for RMP, 94.5%-107% for RTP) and precision (RSD < 11.9 % for RMP, RSD < 11.4 % for RTP), suggesting that it was sensitive and robust for simultaneous quantification of RMP and RTP. The method was successfully applied to analyze RMP and RTP in mouse tissues. In general, the developed method is suitable to monitor RMP and RTP, and provides a useful approach for exploring more detailed effects of remdesivir in treating diseases.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Prodrugs/analysis , Prodrugs/metabolism , Tandem Mass Spectrometry/methods , Adenosine Monophosphate/analysis , Adenosine Monophosphate/metabolism , Adenosine Monophosphate/pharmacology , Alanine/analysis , Alanine/metabolism , Alanine/pharmacology , Animals , Antiviral Agents/analysis , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/metabolism , Chromatography, Liquid/methods , Humans , Liver/chemistry , Liver/drug effects , Liver/metabolism , Male , Mice , Prodrugs/pharmacology
15.
ACS Infect Dis ; 7(2): 471-478, 2021 02 12.
Article in English | MEDLINE | ID: covidwho-1006383

ABSTRACT

A series of 7-deazaadenine ribonucleosides bearing alkyl, alkenyl, alkynyl, aryl, or hetaryl groups at position 7 as well as their 5'-O-triphosphates and two types of monophosphate prodrugs (phosphoramidates and S-acylthioethanol esters) were prepared and tested for antiviral activity against selected RNA viruses (Dengue, Zika, tick-borne encephalitis, West Nile, and SARS-CoV-2). The modified triphosphates inhibited the viral RNA-dependent RNA polymerases at micromolar concentrations through the incorporation of the modified nucleotide and stopping a further extension of the RNA chain. 7-Deazaadenosine nucleosides bearing ethynyl or small hetaryl groups at position 7 showed (sub)micromolar antiviral activities but significant cytotoxicity, whereas the nucleosides bearing bulkier heterocycles were still active but less toxic. Unexpectedly, the monophosphate prodrugs were similarly or less active than the corresponding nucleosides in the in vitro antiviral assays, although the bis(S-acylthioethanol) prodrug 14h was transported to the Huh7 cells and efficiently released the nucleoside monophosphate.


Subject(s)
Antiviral Agents/pharmacology , Prodrugs/pharmacology , Purines/pharmacology , RNA Viruses/drug effects , Ribonucleosides/pharmacology , COVID-19/drug therapy , COVID-19/virology , Cell Line, Tumor , Dengue Virus/drug effects , Encephalitis Viruses, Tick-Borne/drug effects , Humans , Phosphates/pharmacology , Purine Nucleosides , RNA-Dependent RNA Polymerase/metabolism , SARS-CoV-2/drug effects , West Nile virus/drug effects , Zika Virus/drug effects
16.
Sci Rep ; 10(1): 16577, 2020 10 06.
Article in English | MEDLINE | ID: covidwho-834912

ABSTRACT

SARS-CoV-2 is responsible for COVID-19, resulting in the largest pandemic in over a hundred years. After examining the molecular structures and activities of hepatitis C viral inhibitors and comparing hepatitis C virus and coronavirus replication, we previously postulated that the FDA-approved hepatitis C drug EPCLUSA (Sofosbuvir/Velpatasvir) might inhibit SARS-CoV-2. We subsequently demonstrated that Sofosbuvir triphosphate is incorporated by the relatively low fidelity SARS-CoV and SARS-CoV-2 RNA-dependent RNA polymerases (RdRps), serving as an immediate polymerase reaction terminator, but not by a host-like high fidelity DNA polymerase. Other investigators have since demonstrated the ability of Sofosbuvir to inhibit SARS-CoV-2 replication in lung and brain cells; additionally, COVID-19 clinical trials with EPCLUSA and with Sofosbuvir plus Daclatasvir have been initiated in several countries. SARS-CoV-2 has an exonuclease-based proofreader to maintain the viral genome integrity. Any effective antiviral targeting the SARS-CoV-2 RdRp must display a certain level of resistance to this proofreading activity. We report here that Sofosbuvir terminated RNA resists removal by the exonuclease to a substantially higher extent than RNA terminated by Remdesivir, another drug being used as a COVID-19 therapeutic. These results offer a molecular basis supporting the current use of Sofosbuvir in combination with other drugs in COVID-19 clinical trials.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Exonucleases/metabolism , Pneumonia, Viral/drug therapy , Prodrugs/pharmacology , RNA, Viral/drug effects , Sofosbuvir/pharmacology , Adenosine Monophosphate/chemistry , Adenosine Monophosphate/pharmacology , Adenosine Monophosphate/therapeutic use , Alanine/chemistry , Alanine/pharmacology , Alanine/therapeutic use , Antiviral Agents/chemistry , Antiviral Agents/therapeutic use , Betacoronavirus/enzymology , COVID-19 , Coronavirus Infections/virology , Coronavirus RNA-Dependent RNA Polymerase , Drug Discovery/methods , Drug Repositioning/methods , Hepacivirus/drug effects , Hepacivirus/enzymology , Hepatitis C/drug therapy , Hepatitis C/virology , Humans , Pandemics , Pneumonia, Viral/virology , Prodrugs/therapeutic use , RNA, Viral/chemistry , RNA, Viral/metabolism , RNA-Dependent RNA Polymerase/antagonists & inhibitors , RNA-Dependent RNA Polymerase/metabolism , SARS-CoV-2 , Sofosbuvir/chemistry , Sofosbuvir/therapeutic use , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effects
17.
Antiviral Res ; 180: 104857, 2020 08.
Article in English | MEDLINE | ID: covidwho-602131

ABSTRACT

SARS-CoV-2, a member of the coronavirus family, is responsible for the current COVID-19 worldwide pandemic. We previously demonstrated that five nucleotide analogues inhibit the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp), including the active triphosphate forms of Sofosbuvir, Alovudine, Zidovudine, Tenofovir alafenamide and Emtricitabine. We report here the evaluation of a library of nucleoside triphosphate analogues with a variety of structural and chemical features as inhibitors of the RdRps of SARS-CoV and SARS-CoV-2. These features include modifications on the sugar (2' or 3' modifications, carbocyclic, acyclic, or dideoxynucleotides) or on the base. The goal is to identify nucleotide analogues that not only terminate RNA synthesis catalyzed by these coronavirus RdRps, but also have the potential to resist the viruses' exonuclease activity. We examined these nucleotide analogues for their ability to be incorporated by the RdRps in the polymerase reaction and to prevent further incorporation. While all 11 molecules tested displayed incorporation, 6 exhibited immediate termination of the polymerase reaction (triphosphates of Carbovir, Ganciclovir, Stavudine and Entecavir; 3'-OMe-UTP and Biotin-16-dUTP), 2 showed delayed termination (Cidofovir diphosphate and 2'-OMe-UTP), and 3 did not terminate the polymerase reaction (2'-F-dUTP, 2'-NH2-dUTP and Desthiobiotin-16-UTP). The coronaviruses possess an exonuclease that apparently requires a 2'-OH at the 3'-terminus of the growing RNA strand for proofreading. In this study, all nucleoside triphosphate analogues evaluated form Watson-Crick-like base pairs. The nucleotide analogues demonstrating termination either lack a 2'-OH, have a blocked 2'-OH, or show delayed termination. Thus, these nucleotide analogues are of interest for further investigation to evaluate whether they can evade the viral exonuclease activity. Prodrugs of five of these nucleotide analogues (Cidofovir, Abacavir, Valganciclovir/Ganciclovir, Stavudine and Entecavir) are FDA-approved medications for treatment of other viral infections, and their safety profiles are well established. After demonstrating potency in inhibiting viral replication in cell culture, candidate molecules can be rapidly evaluated as potential therapies for COVID-19.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus Infections/virology , Nucleotides/pharmacology , Pneumonia, Viral/virology , RNA-Dependent RNA Polymerase/antagonists & inhibitors , SARS Virus/enzymology , Severe Acute Respiratory Syndrome/virology , Antiviral Agents/chemistry , Antiviral Agents/therapeutic use , Betacoronavirus/enzymology , Betacoronavirus/genetics , COVID-19 , Cidofovir/chemistry , Cidofovir/pharmacology , Cidofovir/therapeutic use , Coronavirus Infections/drug therapy , Dideoxynucleosides/chemistry , Dideoxynucleosides/pharmacology , Dideoxynucleosides/therapeutic use , Ganciclovir/chemistry , Ganciclovir/pharmacology , Ganciclovir/therapeutic use , Guanine/analogs & derivatives , Guanine/chemistry , Guanine/pharmacology , Guanine/therapeutic use , Nucleotides/chemistry , Nucleotides/therapeutic use , Pandemics , Pneumonia, Viral/drug therapy , Prodrugs/chemistry , Prodrugs/pharmacology , Prodrugs/therapeutic use , RNA, Viral/antagonists & inhibitors , RNA, Viral/biosynthesis , SARS Virus/genetics , SARS-CoV-2 , Severe Acute Respiratory Syndrome/drug therapy , Stavudine/chemistry , Stavudine/pharmacology , Stavudine/therapeutic use , Valganciclovir/chemistry , Valganciclovir/pharmacology , Valganciclovir/therapeutic use
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