HCV Inhibitors Research Articles

Deciphering molecular properties and docking studies of hepatitis C and non-hepatitis C antiviral inhibitors – A computational approach

BackgroundHepatitis C is an infectious liver disease with high mortality rate which is caused by Hepatitis C virus. Several treatment methods have been applied to combat this deadly virus including interferons, vaccine and direct acting antivirals (DAAs). However, the later shows promising effects in HCV treatment with lower adverse effect. Specifically, the DAAs target the non-structural proteins (NS3 and NS5B). PurposeThe objective of the present study is to hypothesize an alternative antiviral inhibitor for HCV from the available other antivirals. MethodsComputation of 2D molecular descriptors for the selected antiviral inhibitors followed by clustering the descriptor features. The closely clustered compounds were subjected to the interaction studies against the HCV target protein to validate the cluster result. Results and discussionThe clustering result showed that indinavir (HIV inhibitor) and AT130 (HBV inhibitor) molecule are close to the HCV inhibitor. The indinavir complexed with NS3 protein shows −5.33kcal/mol and AT-130 complexed with NS5B protein possess the binding energy of −8.87kcal/mol. The docking interaction study indicated a better binding affinity than other viral inhibitors. ConclusionFrom the descriptor based feature similarity analysis and the interaction study, it can be concluded that indinavir and AT-130 could be a potential alternative agent for HCV treatment.

Host-directed broad-spectrum antiviral drugs

Viruses completely depend on cellular factors to multiply. In spite of their unique coding features, different viruses are shown to depend upon some common host factors. Consequently, it should be possible to develop broad-spectrum antivirals by targeting them. In the presentation, the author will give an summary of the concept of host-targeting, broad-spectrum antiviral drugs and our work on natural products. The author will specially specialise in metabolites isolated from myxobacteria, one among the highest producers of natural products with host-targeting properties. With viral infections this is not possible. There are currently very few antiviral drugs and those that exist are specific to one type of virus, requiring a diagnostic process before being able to apply treatment. The development of broad-spectrum antivirals would speed up the prescription of treatments, which in many cases, is essential to beat the disease, and would provide a first line of defence against new viruses. "Antiviral drugs on the market today are aimed at specific components of a virus, usually viral enzymes necessary for the multiplication of the virus in infected cells", explains Georgios Koutsoudakis, researcher of Juana Diez's group and first author of the study. Bearing in mind that viruses of different families are genetically quite different, direct action antivirals are tailored to a specific type of virus. Moreover, its potential as an inhibitor of HCV is just as good as an anti-HCV drug already present on the market. This compound is SoraphenA, a product extracted from soil myxobacteria that is targeted at the cellular enzyme Acetyl-Coenzyme A Carboxylase (ACC), a protein involved in the synthesis of lipids within cells. The great advantage of this compound is that because its antiviral activity is mediated by a cell component, it is effective for various genotypes of HCV and is little susceptible to developing drug resistance. Given that not only HIV and HCV but many other viruses, including the emerging Dengue virus, West Nile virus and Chikungunya virus, depend on the lipid cellular metabolism to multiply, it is possible that the antiviral activity of SorA will go beyond HIV and HCV, which is something that the laboratories of Dr. Diez and Dr. Meyerhans are already testing. The concept of broad-spectrum antivirals targeting host cells and obtained from nature as well as the characteristics of the inhibition of HCV mediated by SorA are published in two articles. It is still very early to speak of SorA in treatment. From an antiviral compound being effective in cell cultures to it coming to be used on patients is very long process. But the experimental discoveries so far are very promising. The development of medicine with broad-spectrum antiviral activities may be a long pursued goal in drug discovery. It has been shown that blocking co-opted host-factors abrogates the replication of the many viruses, yet the event of such host-targeting drugs has been met with scepticism mainly thanks to toxicity issues and poor translation to in vivo models. With the arrival of latest and more powerful screening assays and prediction tools, the thought of a drug which will efficiently treat a good range of viral infections by blocking specific host functions has re-bloomed. Here we critically review the state-of-the-art in broad-spectrum antiviral discovery. We discuss putative targets and treatment strategies, with particular specialise in natural products as promising starting points for antiviral lead development. Viral infections affect millions of people every year and are a global public health threat. Infections with viruses like HIV or HCV can become persistent and may produce severe diseases as AIDS or hepatocellular carcinoma, respectively. (Re-)emerging viruses like WNV, DENV or CHIKV are spreading without proper control mechanisms. Thus, there are no effective vaccines and the treatment options against most virus threads are still limited. In this context, the development of new antivirals remains an important issue. Viruses need cellular host factors to complete their life cycles. Hundreds of these host-factors have been identified. Interestingly, several viruses use the same host factors so that chemical inhibition of these may lead to broad-spectrum viral inhibition. Broad-spectrum host-acting antivirals (HAAs) may increase the barrier to resistance development and reduce the complexity of co-infection treatments. In this thesis a high-throughput anti-HIV screening was applied to a myxobacteria metabolites library. Compounds with high anti-HIV activity and low toxicity were identified as hits and 2 of them (ratjadone A and soraphen A) were selected for further research. Ratjadone A inhibits the CRM1-mediated nuclear export and soraphen A inhibits the de novo fatty acid synthesis. Both drugs inhibit HIV and we described the mechanisms of inhibition of both compounds. The data presented in this thesis suggest that the use of host-acting antivirals as a broad-spectrum therapy is a feasible option.

A Potent, Selective, and Orally Bioavailable HCV NS5A Inhibitor for Treatment of Hepatitis C Virus: (S)-1-((R)-2-(Cyclopropanecarboxamido)-2-phenylacetyl)-N-(4-phenylthiazol-2-yl)pyrrolidine-2-carboxamide.

Starting from the initial lead 4-phenylthiazole 18, a modest HCV inhibitor (EC50 = 9440 nM), a series of structurally related thiazole derivatives has been identified as a novel chemical class of potent and selective HCV NS5A inhibitors. The introduction of a carboxamide group between the thiazole and pyrrolidine ring (42) of compound 18 resulted in a dramatic increase in activity (EC50 = 0.92 nM). However, 42 showed only moderate pharmacokinetic properties and limited oral bioavalability of 18.7% in rats. Further optimization of the substituents at the 4-position of the thiazole ring and pyrrolidine nitrogen of the lead compound 42 led to the identification of compound 57, a highly potent and selective NS5A inhibitor of HCV (EC50 = 4.6 nM), with greater therapeutic index (CC50/EC50 > 10000). Pharmacokinetic studies revealed that compound 57 had a superior oral exposure and desired bioavailability of 45% after oral administration in rats.

Design and Synthesis of Cajanine Analogues against Hepatitis C Virus through Down-Regulating Host Chondroitin Sulfate N-Acetylgalactosaminyltransferase 1.

There still remains a need to develop new anti-HCV agents with distinct mechanism of action (MOA) due to the occurrence of resistance to direct-acting antiviral agents (DAAs). Cajanine, a stilbenic component isolated from Cajanus cajan L., was identified as a potent HCV inhibitor by phenotypic screening in this work (EC50 = 3.17 ± 0.75 μM). The intensive structure optimization provided significant insights into the structure-activity relationships. Furthermore, the MOA study revealed that cajanine inhibited HCV replications via down-regulating a cellular protein chondroitin sulfate N-acetylgalactosaminyltransferase 1. In consistency with this host-targeting mechanism, cajanine showed the similar magnitude of inhibitory activity against both drug-resistant and wild-type HCV and synergistically inhibited HCV replication with approved DAAs. Taken together, our study not only presented cajanine derivatives as a novel class of anti-HCV agents but also discovered a promising anti-HCV target to combat drug resistance.

A multi-center clinical observation on safety and efficacy of a plasma derived coagulator factor Ⅷ for treatment of patients with hemophilia A

To evaluate the efficacy and safety of homemade plasma derived coagulation factor Ⅷ in patients with hemophilia A. Patients with congenital hemophilia A who met the inclusive and exclusive criteria were enrolled in the study after informed consent. The doses of factor Ⅷ were calculated according to the weight, disease severity etc. FⅧ activity and infusion efficacy value at 10 min and 60 min after infusion were recorded, as well as adverse events and validity rating according to the improvement of clinical syndromes. Viral infections including HBV, HCV, HIV and FⅧ inhibitor were determined after 3 and 6 months. A total of 65 patients were enrolled in this study, all of whom were evaluable for drug safety. Treatment efficacy was evaluated in 60 patients and 57 cases completed the trial finally. In this 57 cases, most (52/57) subjects were of middle and severe hemophilia A mainly characterized by joint bleeding. Overall response rate of acute bleeding events was classified as "excellent" (70.00%) or "better" (30.00%). The non-responder was 0. FⅧ activity and infusion efficiency value of first administration after 10 min and 60 min improved significantly [10 min: (123.66±47.54)%; 60 min: (108.05±43.24)%]. The incidence of adverse events was 1.54%. Neither allergic reaction nor reactivation of HBV, HCV, HIV was detected after treatment of 3 and 6 months. No FⅧ inhibitor negative patients converted to positive during follow-up. This homemade plasma derived coagulation factor Ⅷ is safe and effective for the treatment of acute bleeding in patients with hemophilia A.

Synthesis and In Vitro Activity of Pyrrolo[3,4-d]pyrimidine-2,5-diones as Potential Non-nucleoside HCV Inhibitors

Synthesis and In Vitro Activity of Pyrrolo[3,4-d]pyrimidine-2,5-diones as Potential Non-nucleoside HCV Inhibitors

Structure-based optimization and derivatization of 2-substituted quinolone-based non-nucleoside HCV NS5B inhibitors with submicromolar cellular replicon potency

HCV NS5B polymerase is an attractive and validated target for anti-HCV therapy. Starting from our previously identified 2-aryl quinolones as novel non-nucleoside NS5B polymerase inhibitors, structure-based optimization furnished 2-alkyl-N-benzyl quinolones with improved antiviral potency by employing privileged fragment hybridization strategy. The N-(4-chlorobenzyl)-2-(methoxymethyl)quinolone derivative 5f proved to be the best compound of this series, exhibiting a selective sub-micromolar antiviral effect (EC50=0.4μM, SI=10.8) in Huh7.5.1 cells carrying a HCV genotype 2a. Considering the undesirable pharmacokinetic property of the highly substituted quinolones, a novel chemotype of 1,6-naphthyridine-4,5-diones were evolved via scaffold hopping, affording brand new structure HCV inhibitors with compound 6h (EC50 (gt2a)=2.5μM, SI=7.2) as a promising hit. Molecular modeling studies suggest that both of 2-alkyl quinolones and 1,6-naphthyridine-4,5-diones function as HCV NS5B thumb pocket II inhibitors.

HCV Inhibitors: Role of Compounds from Botanical Sources.

The developing number of hepatitis C virus infected cases worldwide has threatened people's health. The available therapeutic options have low specificity, side effects and high rate of drug resistance and thus potentiate the need for novel effective anti-HCV drugs. Agents obtained from natural sources offer an enormous scope of structural diversity and broad therapeutic range of coverage. This review summarizes the research and development of anti-HCV agents (plant extracts/isolated components) obtained from various natural sources along with the associated mechanism of HCV inhibition. Some of the reported examples include triterpenes, naringenin, Proanthocyanidin, curcumin, Epigallocatechin-3-gallate, quercetin and abrogates having diverse anti-HCV properties. The compiled knowledge regarding anti-HCV agents from natural sources will provide considerable information for developing novel safe and effective anti-HCV drugs.

Engineered exosomes boost the HCV NS3-specific CD8+ T lymphocyte immunity in humans

At the present, no anti-Hepatitis C virus (HCV) HCV vaccine is available, and many patients failed the treatment with new class of HCV inhibitors. In HCV infection, both experimental and clinic evidences indicate that a strong CTL-immune response could have significant therapeutic effects. We developed an innovative anti-HCV CD8+ T immunogen based on the uploading in engineered exosomes of full-length HCV-NS3 protein. HCV NS3 exosomes appeared immunogenic when injected in mice, as proven by the detection of a memory CD8+ T lymphocyte pool two weeks after the last of three immunizations. On the other hand, dendritic cells isolated from PBMCs of HCV infected patients activate autologous HCV NS3-specific CD8+ T lymphocytes upon challenge with HCV NS3 exosomes. These results provide the proof-of-principle that engineered exosomes can boost the CD8+ T cell immunity in HCV-infected patients, thus representing a suitable option for patients resisting the therapies with recently discovered HCV inhibitors.

A new series of HCV inhibitors based on a 2-(thieno[2,3b]pyridin-2-yl)-1,3,4-oxadiazole scaffold

A new series of HCV inhibitors based on a 2-(thieno[2,3-b]pyridin-2-yl)-1,3,4-oxadiazole scaffold was developed.

QSAR and Molecular Docking Directed Synthesis and Preliminary Evaluation of Novel Non-Nucleoside HCV NS5B Polymerase Inhibitors

In HCV genome, the NS5B RNA-dependent RNA polymerase (RdRp) plays central role in the replication. It is the most preferred target for design and screening of small molecule HCV inhibitors. From in house compound library screening using NS5B polymerase enzymatic assay, we identified some benzimidazole derivatives. The activities were predicted using the QSAR generated models. Along with QSAR predictions, molecular docking studies help to study binding of these series of compounds at allosteric pocket (AP-1). Keywords: Benzimidazole derivatives, anti-HCV agents, NS5B polymerase inhibitors, molecular docking.

Design, synthesis, and delivery studies of organotin(IV) based HCV inhibitor.

Tributylstannic[3-(3,5 -dimethylphenylamido)propionate] is synthesized and characterized by elemental analysis, FT-IR, multinuclear NMR ((1)H, (13)C and (119)Sn) and mass spectrometry. The organic anion was found to act as monodentate O-bound ligand in solution. The compound was screened for the anti-HCV potency by the Gaussia luciferase Assay using infected Huh 7.5 cells (human hepatocellular cell) and is found active against HCV with logIC50 1.2nM in the cell-based assay. Cationic surfactant cetyl N,N,N-trimethylammoniumbromide (CTAB) was used to study the interactions of the organotin(IV) complex with positively charged micelles of the surfactant acting as a model cell membrane. The thermodynamics parameters of complex- CTAB interaction concluded that the complex is located in the palisade layer of CTAB micelles. The increase in absorbance of visible spectra of the compound confirmed its solubilization into micelles. The two carbonyl oxygen's were found to be binding sites of the complex with CTAB.

Design, Synthesis and Structure-Activity Relationship Optimization of Lycorine Derivatives for HCV Inhibition.

Lycorine is reported to be a multifunctional compound. We previously showed that lycorine is an HCV inhibitor with strong activity. Further research on the antivirus mechanism indicated that lycorine does not affect the enzymes that are indispensable to HCV replication but suppresses the expression of Hsc70 in the host cell to limit HCV replication. However, due to the cytotoxicity and apoptosis induction of lycorine, lycorine is unsafe to be a anti-HCV agent for clinical application. As a result of increasing interest, its structure was optimized for the first time and a novel series of lycorine derivatives was synthesized, all of which lost their cytotoxicity to different degrees. Structure-activity analysis of these compounds revealed that disubstitution on the free hydroxyl groups at C1 and C2 and/or degradation of the benzodioxole group would markedly reduce the cytotoxicity. Furthermore, an α, β-unsaturated ketone would improve the HCV inhibitory activity of lycorine. The C3-C4 double bond is crucial to the anti-HCV activity because hydrogenation of this double bond clearly weakened HCV inhibition.

High-Throughput Screening, Discovery, and Optimization To Develop a Benzofuran Class of Hepatitis C Virus Inhibitors.

Using a high-throughput, cell-based HCV luciferase reporter assay to screen a diverse small-molecule compound collection (∼ 300,000 compounds), we identified a benzofuran compound class of HCV inhibitors. The optimization of the benzofuran scaffold led to the identification of several exemplars with potent inhibition (EC50 < 100 nM) of HCV, low cytotoxicity (CC50 > 25 μM), and excellent selectivity (selective index = CC50/EC50, > 371-fold). The structure-activity studies culminated in the design and synthesis of a 45-compound library to comprehensively explore the anti-HCV activity. The identification, design, synthesis, and biological characterization for this benzofuran series is discussed.

Rethinking the old antiviral drug moroxydine: Discovery of novel analogues as anti-hepatitis C virus (HCV) agents.

The discovery of a novel class of HCV inhibitors is described. The new amidinourea compounds were designed as isosteric analogues of the antiviral drug moroxydine. The two derivatives 11g and 11h showed excellent HCV inhibition activity and viability and proved to inhibit a step(s) of the RNA replication. The new compounds have been synthesized in only three synthetic steps from cheap building blocks and in high yields, thus turning to be promising drug candidates in the development of cheaper HCV treatments.

Prediction of the ligands having the inhibitory activity against the HCV non-structural protein 5B polymerase

ObjectiveTo find similar compounds of rhodanine inhibitors of HCV non-structural protein 5B (NS5B) through exploring the PubChem database. MethodsWe used the data mining of these ligands and we studied molecular docking of these ligands with the enzyme HCV NS5B for knowing inhibitory activity. We used the the Knime software for the data mining and the USCF Chimera and Molecular Operating Environment for study the molecular docking. ResultsAs a result, the discovery was two new inhibitors of NS5B HCV, namely CID 211702 and CID 13752. ConclusionsTwo new ligands, CID 211702 and CID 13752, were discovered for the inhibition of the HCV and can be used to invent new medicines against the cancerous diseases.

Structure-activity relationship studies on quinoxalin-2(1H)-one derivatives containing thiazol-2-amine against hepatitis C virus leading to the discovery of BH6870.

Chronic hepatitis C virus infection represents a serious global public health problem, typically resulting in fibrosis, cirrhosis, and ultimately hepatocellular carcinoma. Based on our previous discovery of lead compound 2 (Liu et al. J Med Chem 54:5747-5768, 2011), 35 new quinoxalinone derivatives were explored in this study. Outline of the structure-activity relationships (SARs) revealed that compound BH6870 (36) showed high anti-HCV potency ([Formula: see text]) and a good cell safety index (SI [Formula: see text]). SARs analysis indicated that quinoxalin-2(1H)-one containing a 4-aryl-substituted thiazol-2-amine moiety was optimal for antiviral activity. Introducing a hydrogen-bond acceptor (such as ester or amide group) at the C-3 position of quinoxalin-2(1H)-one was beneficial for the antiviral potency, and especially, N,N-disubstituted amide was far superior to N-monosubstituted amide. Incorporation of more than one halogen (fluorine or chlorine atom) or a strong electron-withdrawing group on the benzene ring of the thiazole-phenyl moiety might reduce electron atmosphere density further and resulted in a dramatical loss of activity. The NH-group of the lactam moiety was clearly required for anti-HCV activity. Design and synthesis of quinoxalin-2(1H)-one derivatives as new non-nucleoside small-molecule HCV inhibitors. BH6870 (36), showing higher antiviral potency and a good cell safety index, was identified.

Новые гетероциклические ингибиторы вируса гепатита C, включающие 2-аминометил-1&lt;I&gt;H&lt;/I&gt;-индольный фрагмент

Фокусированная библиотека гетероциклических соединений, включающих фрагмент 2-аминометил-1H-бензимидазола (1 – 19), 2-аминометилиндола (20 – 83), бензофуран-2-илметиламина (84 – 92) и 2-пиперазин-1-илметилбензоксазола (93), была проскринирована на антивирусную активность в отношении вируса гепатита C (HCV) in vitro. Представлены схемы химического синтеза и данные по антивирусной активности/цитотоксичности ряда соединений. Вещества, включающие фрагмент бензоксазола-2-илметиламина, в подавляющем большинстве являлись микромолярными ингибиторами на модели клеточной линии гепатомы человека Huh7.3, зараженной HCV in vitro, но оказались неактивными на модели РНК-репликона HCV. Исключение составил 9-метил-N (6)-(3-нитрофенил)-2,3,4,9-тетрагидро-1H-карбазол-1,6-диамин (67), проявивший наномолярную антивирусную активность на обеих моделях. Наиболее активными и селективными были (пиперазин-1-ил)-[(1H-индол-2-илметил)пиперидин-4-ил]-кетоны (EC50 0,31 – 2,2 μM, CC50 10,2 – 110 μM), и 2-(1,2,3a,4,5,6-гексагидропиразино[3,2,1-ол]- карбазол-3-ил)ацетамид (EC50 = (1,69 ± 0,5) μM, CC50 = (114 ± 42) μM). Два наиболее селективных ингибитора 28 (TI50 = 52) и 77 (TI50 = 68) были выбраны для дальнейших доклинических исследований.

The Changing Face of Hepatitis C: Recent Advances on HCV Inhibitors Targeting NS5A

Current treatment for HCV infections consists of approved direct acting antivirals (DAAs), viz. the protease inhibitors (boceprevir, telaprevir, and simeprevir), NS5B polymerase inhibitors (sofosbuvir) and NS5A inhibitor (ledipasvir) in combination with pegylated interferon α and ribavirin). These treatments have made a great improvement in the treatment of chronic HCV infections in recent years, but their adverse side effects, emergence of resistant mutants, high cost, and increased pill burden have limited their clinical use. Recently, with the increasing knowledge in understanding the HCV life cycle, more targets have been recognized. NS5A protein plays a critical role in assembly of infectious HCV particles and offering potential for HCV therapies. Therefore, discovery and development of novel DAAs targeting NS5A with novel mechanisms of action, is of great necessity to improve the quality of existing HCV treatments. In the present review, we discuss recent advances with NS5A inhibitors with potent anti-HCV activity, and the potential for the development of HCV NS5A inhibitors to combat HCV infections.

A novel small-molecule inhibitor of hepatitis C virus replication acts by suppressing signal transducer and activator of transcription 3.

Hepatitis C virus (HCV) infects hepatocytes and causes liver damage. The aim of this study was to identify new classes of host-targeting anti-HCV compounds that may provide novel approaches for antiviral treatment regimens. Cell culture-derived HCV (HCVcc), replicons and pseudoparticles were used in combination with high-throughput screening, reporter gene assays and cytotoxicity and signalling pathway analyses. A small-molecule inhibitor of HCV, N-(cyclopropyl(phenyl)methyl)thieno[2,3-d]pyrimidin-4-amine, designated IB-32, was identified by screening a compound library with a Jc1-luc HCVcc assay. By using various virus models, HCV replication was identified as the predominant step of IB-32's action. IB-32 inhibited HCVcc (genotype 2a) and HCV replicons (genotype 1b) at low nanomolar ranges (with IC50s of 40 ± 8 and 100 ± 15 nM, respectively). IB-32 was found to be non-toxic when tested against a panel of human cell lines in vitro at the effective antiviral dose. Mechanistically, IB-32 strongly inhibited STAT3 (Tyr705) phosphorylation, a necessary cellular factor for HCV replication and a pivotal therapeutic target for multiple cancers. Furthermore, the inhibition of HCV replication by IB-32 was augmented in cells with STAT3 knockdown. In contrast, the inhibitory effect of IB-32 was attenuated in cells overexpressing a constitutively active form of STAT3. The results presented here identify a promising STAT3-targeting anti-HCV therapeutic candidate. This novel small molecule could be further optimized and developed for use as both an antiviral and an anti-cancer drug.