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Pharmaceuticals (Basel, Switzerland) May 2022The synthetic compounds, Tilorone and Cridanimod, have the antiviral activity which initially had been ascribed to the capacity to induce interferon. Both drugs induce...
The synthetic compounds, Tilorone and Cridanimod, have the antiviral activity which initially had been ascribed to the capacity to induce interferon. Both drugs induce interferon in mice but not in humans. This study investigates whether these compounds have the antiviral activity in mice and rats since rats more closely resemble the human response. Viral-infection models were created in CD-1 mice and Wistar rats. Three strains of Venezuelan equine encephalitis virus were tested for the performance in these models. One virus strain is the molecularly cloned attenuated vaccine. The second strain has major virulence determinants converted to the wild-type state which are present in virulent strains. The third virus has wild-type virulence determinants, and in addition, is engineered to express green fluorescent protein. Experimentally infected animals received Tilorone or Cridanimod, and their treatment was equivalent to the pharmacopoeia-recomended human treatment regimen. Tilorone and Cridanimod show the antiviral activity in mice and rats and protect the mice from death. In rats, both drugs diminish the viremia. These drugs do not induce interferon-alpha or interferon-beta in rats. The presented observations allow postulating the existence of an interferon-independent and species-independent mechanism of action.
PubMed: 35631443
DOI: 10.3390/ph15050617 -
Chemical Research in Toxicology May 2021Acetylcholinesterase (AChE) is an important drug target in neurological disorders like Alzheimer's disease, Lewy body dementia, and Parkinson's disease dementia as well...
Acetylcholinesterase (AChE) is an important drug target in neurological disorders like Alzheimer's disease, Lewy body dementia, and Parkinson's disease dementia as well as for other conditions like myasthenia gravis and anticholinergic poisoning. In this study, we have used a combination of high-throughput screening, machine learning, and docking to identify new inhibitors of this enzyme. Bayesian machine learning models were generated with literature data from ChEMBL for eel and human AChE inhibitors as well as butyrylcholinesterase inhibitors (BuChE) and compared with other machine learning methods. High-throughput screens for the eel AChE inhibitor model identified several molecules including tilorone, an antiviral drug that is well-established outside of the United States, as a newly identified nanomolar AChE inhibitor. We have described how tilorone inhibits both eel and human AChE with IC's of 14.4 nM and 64.4 nM, respectively, but does not inhibit the closely related BuChE IC > 50 μM. We have docked tilorone into the human AChE crystal structure and shown that this selectivity is likely due to the reliance on a specific interaction with a hydrophobic residue in the peripheral anionic site of AChE that is absent in BuChE. We also conducted a pharmacological safety profile (SafetyScreen44) and kinase selectivity screen (SelectScreen) that showed tilorone (1 μM) only inhibited AChE out of 44 toxicology target proteins evaluated and did not appreciably inhibit any of the 485 kinases tested. This study suggests there may be a potential role for repurposing tilorone or its derivatives in conditions that benefit from AChE inhibition.
Topics: Acetylcholinesterase; Animals; Antiviral Agents; Cholinesterase Inhibitors; Dose-Response Relationship, Drug; Electrophorus; Humans; Machine Learning; Molecular Docking Simulation; Molecular Structure; Structure-Activity Relationship; Tilorone
PubMed: 33400519
DOI: 10.1021/acs.chemrestox.0c00466 -
ACS Omega Mar 2021Severe acute respiratory coronavirus 2 (SARS-CoV-2) is a newly identified virus that has resulted in over 2.5 million deaths globally and over 116 million cases globally...
Severe acute respiratory coronavirus 2 (SARS-CoV-2) is a newly identified virus that has resulted in over 2.5 million deaths globally and over 116 million cases globally in March, 2021. Small-molecule inhibitors that reverse disease severity have proven difficult to discover. One of the key approaches that has been widely applied in an effort to speed up the translation of drugs is drug repurposing. A few drugs have shown activity against Ebola viruses and demonstrated activity against SARS-CoV-2 . Most notably, the RNA polymerase targeting remdesivir demonstrated activity and efficacy in the early stage of the disease in humans. Testing other small-molecule drugs that are active against Ebola viruses (EBOVs) would appear a reasonable strategy to evaluate their potential for SARS-CoV-2. We have previously repurposed pyronaridine, tilorone, and quinacrine (from malaria, influenza, and antiprotozoal uses, respectively) as inhibitors of Ebola and Marburg viruses in HeLa cells and mouse-adapted EBOV in mice . We have now tested these three drugs in various cell lines (VeroE6, Vero76, Caco-2, Calu-3, A549-ACE2, HUH-7, and monocytes) infected with SARS-CoV-2 as well as other viruses (including MHV and HCoV 229E). The compilation of these results indicated considerable variability in antiviral activity observed across cell lines. We found that tilorone and pyronaridine inhibited the virus replication in A549-ACE2 cells with IC values of 180 nM and IC 198 nM, respectively. We used microscale thermophoresis to test the binding of these molecules to the spike protein, and tilorone and pyronaridine bind to the spike receptor binding domain protein with values of 339 and 647 nM, respectively. Human C for pyronaridine and quinacrine is greater than the IC observed in A549-ACE2 cells. We also provide novel insights into the mechanism of these compounds which is likely lysosomotropic.
PubMed: 33778258
DOI: 10.1021/acsomega.0c05996 -
ACS Omega Apr 2023Pyronaridine, tilorone and quinacrine are cationic molecules that have activity against Ebola, SARS-CoV-2 and other viruses. All three molecules have also demonstrated...
Pyronaridine, tilorone and quinacrine are cationic molecules that have activity against Ebola, SARS-CoV-2 and other viruses. All three molecules have also demonstrated activity against Ebola in mice, while pyronaridine showed efficacy against SARS-CoV-2 in mice. We have recently tested these molecules and other antivirals against human organic cation transporters (OCTs) and apical multidrug and toxin extruders (MATEs). Quinacrine was found to be an inhibitor of OCT2, while tilorone and pyronaridine were less potent, and these displayed variability depending on the substrate used. To assess whether any of these three molecules have other potential interactions with additional transporters, we have now screened them at 10 μM against various human efflux and uptake transporters including P-gp, OATP1B3, OAT1, OAT3, MRP1, MRP2, MRP3, BCRP, as well as confirmational testing against OCT1, OCT2, MATE1 and MATE2K. Interestingly, in this study tilorone appears to be a more potent inhibitor of OCT1 and OCT2 than pyronaridine or quinacrine. However, both pyronaridine and quinacrine appear to be more potent inhibitors of MATE1 and MATE2K. None of the three compounds inhibited MRP1, MRP2, MRP3, OAT1, OAT3, P-gp or OATP1B3. Similarly, we previously showed that tilorone and pyronaridine do not inhibit OATP1B1 and have confirmed that quinacrine behaves similarly. In total, these observations suggest that the three compounds only appear to interact with OCTs and MATEs to differing extents, suggesting they may be involved in fewer clinically relevant drug-transporter interactions involving pharmaceutical substrates of the other major transporters tested.
PubMed: 37033868
DOI: 10.1021/acsomega.3c00724 -
RSC Medicinal Chemistry Jul 2021Several synthetic heterocyclic small molecules like imiquimod, resiquimod, CL097, CL075, bromopirone, tilorone, loxoribine and isatoribine demonstrated TLR7/8 agonistic... (Review)
Review
Several synthetic heterocyclic small molecules like imiquimod, resiquimod, CL097, CL075, bromopirone, tilorone, loxoribine and isatoribine demonstrated TLR7/8 agonistic activity and relatively modest structural changes in such molecules result in major variation in the TLR7 and/or TLR8 activity. A strict dependency of the electronic configuration of the heterocyclic system was also observed to influence the agonistic activity. In the present review, an evolution of imidazole based TLR7/8 agonist from imidazoquinoline based scaffold is delineated along with the elaboration of detailed structure activity relationship (SAR) in each chemotype. The structural and activity details of not only the active compounds but also the related inactive compounds are included to better understand the SAR. TLR7/8 agonists are emerging as promising vaccine adjuvant candidates and the present SAR and structural information will provide a road map towards the identification of more potent and appropriate candidates for further drug discovery.
PubMed: 34355178
DOI: 10.1039/d1md00031d -
BioRxiv : the Preprint Server For... Dec 2020SARS-CoV-2 is a newly identified virus that has resulted in over 1.3 M deaths globally and over 59 M cases globally to date. Small molecule inhibitors that reverse...
SARS-CoV-2 is a newly identified virus that has resulted in over 1.3 M deaths globally and over 59 M cases globally to date. Small molecule inhibitors that reverse disease severity have proven difficult to discover. One of the key approaches that has been widely applied in an effort to speed up the translation of drugs is drug repurposing. A few drugs have shown activity against Ebola virus and demonstrated activity against SARS-CoV-2 . Most notably the RNA polymerase targeting remdesivir demonstrated activity and efficacy in the early stage of the disease in humans. Testing other small molecule drugs that are active against Ebola virus would seem a reasonable strategy to evaluate their potential for SARS-CoV-2. We have previously repurposed pyronaridine, tilorone and quinacrine (from malaria, influenza, and antiprotozoal uses, respectively) as inhibitors of Ebola and Marburg virus in HeLa cells and of mouse adapted Ebola virus in mouse . We have now tested these three drugs in various cell lines (VeroE6, Vero76, Caco-2, Calu-3, A549-ACE2, HUH-7 and monocytes) infected with SARS-CoV-2 as well as other viruses (including MHV and HCoV 229E). The compilation of these results indicated considerable variability in antiviral activity observed across cell lines. We found that tilorone and pyronaridine inhibited the virus replication in A549-ACE2 cells with IC values of 180 nM and IC 198 nM, respectively. We have also tested them in a pseudovirus assay and used microscale thermophoresis to test the binding of these molecules to the spike protein. They bind to spike RBD protein with K values of 339 nM and 647 nM, respectively. Human C for pyronaridine and quinacrine is greater than the IC hence justifying evaluation. We also provide novel insights into their mechanism which is likely lysosomotropic.
PubMed: 33299990
DOI: 10.1101/2020.12.01.407361 -
Microorganisms Dec 2021Rift Valley fever (RVF) is a mosquito-borne zoonotic disease endemic to Africa and the Middle East that can affect humans and ruminant livestock. Currently, there are no...
Rift Valley fever (RVF) is a mosquito-borne zoonotic disease endemic to Africa and the Middle East that can affect humans and ruminant livestock. Currently, there are no approved vaccines or therapeutics for the treatment of severe RVF disease in humans. Tilorone-dihydrochloride (Tilorone) is a broad-spectrum antiviral candidate that has previously shown efficacy against a wide range of DNA and RNA viruses, and which is clinically utilized for the treatment of respiratory infections in Russia and other Eastern European countries. Here, we evaluated the antiviral activity of Tilorone against Rift Valley fever virus (RVFV). In vitro, Tilorone inhibited both vaccine (MP-12) and virulent (ZH501) strains of RVFV at low micromolar concentrations. In the mouse model, treatment with Tilorone significantly improved survival outcomes in BALB/c mice challenged with a lethal dose of RVFV ZH501. Treatment with 30 mg/kg/day resulted in 80% survival when administered immediately after infection. In post-exposure prophylaxis, Tilorone resulted in 30% survival at one day after infection when administered at 45 mg/kg/day. These findings demonstrate that Tilorone has potent antiviral efficacy against RVFV infection in vitro and in vivo and supports further development of Tilorone as a potential antiviral therapeutic for treatment of RVFV infection.
PubMed: 35056541
DOI: 10.3390/microorganisms10010092 -
BMC Infectious Diseases Nov 2016Bacillus anthracis, the causative agent of anthrax, is a spore forming and toxin producing rod-shaped bacterium that is classified as a category A bioterror agent. This... (Review)
Review
BACKGROUND
Bacillus anthracis, the causative agent of anthrax, is a spore forming and toxin producing rod-shaped bacterium that is classified as a category A bioterror agent. This pathogenic microbe can be transmitted to both animals and humans. Clinical presentation depends on the route of entry (direct contact, ingestion, injection or aerosolization) with symptoms ranging from isolated skin infections to more severe manifestations such as cardiac or pulmonary shock, meningitis, and death. To date, anthrax is treatable if antibiotics are administered promptly and continued for 60 days. However, if treatment is delayed or administered improperly, the patient's chances of survival are decreased drastically. In addition, antibiotics are ineffective against the harmful anthrax toxins and spores. Therefore, alternative therapeutics are essential. In this review article, we explore and discuss advances that have been made in anthrax therapy with a primary focus on alternative pre-approved and novel antibiotics as well as anti-toxin therapies.
METHODS
A literature search was conducted using the University of Manitoba search engine. Using this search engine allowed access to a greater variety of journals/articles that would have otherwise been restricted for general use. In order to be considered for discussion for this review, all articles must have been published later than 2009.
RESULTS
The alternative pre-approved antibiotics demonstrated high efficacy against B. anthracis both in vitro and in vivo. In addition, the safety profile and clinical pharmacology of these drugs were already known. Compounds that targeted underexploited bacterial processes (DNA replication, RNA synthesis, and cell division) were also very effective in combatting B. anthracis. In addition, these novel compounds prevented bacterial resistance. Targeting B. anthracis virulence, more specifically the anthrax toxins, increased the length of which treatment could be administered.
CONCLUSIONS
Several novel and pre-existing antibiotics, as well as toxin inhibitors, have shown increasing promise. A combination treatment that targets both bacterial growth and toxin production would be ideal and probably necessary for effectively combatting this armed bacterium.
Topics: Alpha-Globulins; Anthrax; Anti-Bacterial Agents; Antibiotics, Antineoplastic; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antigens, Bacterial; Antitoxins; Bacillus anthracis; Bacterial Toxins; DNA Helicases; Daunorubicin; Doxorubicin; Drug Discovery; Fluoroquinolones; Humans; Interferon Inducers; Levofloxacin; Linezolid; Moxifloxacin; Ofloxacin; Polyketides; Serine Proteinase Inhibitors; Tilorone; Virulence
PubMed: 27809794
DOI: 10.1186/s12879-016-1951-y -
Bulletin of Experimental Biology and... Oct 2021We studied the effect of tilorone on the dynamics of IFNα, IFNγ, and IL-1β levels in the lung tissue and blood serum in relation to viral load in the lungs of BALB/c...
We studied the effect of tilorone on the dynamics of IFNα, IFNγ, and IL-1β levels in the lung tissue and blood serum in relation to viral load in the lungs of BALB/c mice with pneumonia caused by influenza virus A/Aichi/2/68 (H3N2). Tilorone was administered per os in doses of 40, 150, and 540 μg per mouse 6, 30, and 78 h postinfection, which simulated the drug regimen used in the clinic for the treatment of influenza and acute respiratory viral infections in Russia and post-Soviet countries. Tilorone reduced viral load with the maximum amplitude (2-3 lg) after 1-2 administrations. The results of studying the dynamics of the cytokine levels in the infected animals in general support the previous hypothesis that, in repeated dosing, tilorone enhances the IFN response (compensates for its deficiency) at the early stages of acute respiratory viral infections and suppresses (damps) excessive production of IFN and proinflammatory cytokines at the later stages.
Topics: Animals; Antiviral Agents; Drug Administration Schedule; Host-Pathogen Interactions; Influenza A Virus, H3N2 Subtype; Interferon Inducers; Interferon-alpha; Interferon-gamma; Interleukin-1beta; Lung; Male; Mice; Mice, Inbred BALB C; Orthomyxoviridae Infections; Tilorone; Viral Load
PubMed: 34705177
DOI: 10.1007/s10517-021-05306-0 -
ACS Medicinal Chemistry Letters Aug 2020Pyronaridine, tilorone, and quinacrine were recently identified by a machine learning model and demonstrated and activity against Ebola virus (EBOV) and represent...
Pyronaridine, tilorone, and quinacrine were recently identified by a machine learning model and demonstrated and activity against Ebola virus (EBOV) and represent viable candidates for drug repurposing. The target for these molecules was previously unknown. These drugs have now been docked into the crystal structure of the ebola glycoprotein and then experimentally validated using microscale thermophoresis to generate values for tilorone (0.73 μM), pyronaridine (7.34 μM), and quinacrine (7.55 μM). These molecules were shown to bind with a higher affinity than the previously reported toremifene (16 μM). These three structures provide more insight into the structural diversity of ebola glycoprotein inhibitors which can be utilized in the discovery and design of additional inhibitors.
PubMed: 32832035
DOI: 10.1021/acsmedchemlett.0c00298