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Structure (London, England : 1993) Mar 2021The hERG channel is a voltage-gated potassium channel involved in cardiac repolarization. Off-target hERG inhibition by drugs has become a critical issue in the...
The hERG channel is a voltage-gated potassium channel involved in cardiac repolarization. Off-target hERG inhibition by drugs has become a critical issue in the pharmaceutical industry. The three-dimensional structure of the hERG channel was recently reported at 3.8-Å resolution using cryogenic electron microscopy (cryo-EM). However, the drug inhibition mechanism remains unclear because of the scarce structural information regarding the drug- and potassium-bound hERG channels. In this study, we obtained the cryo-EM density map of potassium-bound hERG channel complexed with astemizole, a well-known hERG inhibitor that increases risk of potentially fatal arrhythmia, at 3.5-Å resolution. The structure suggested that astemizole inhibits potassium conduction by binding directly below the selectivity filter. Furthermore, we propose a possible binding model of astemizole to the hERG channel and provide insights into the unusual sensitivity of hERG to several drugs.
Topics: Astemizole; Binding Sites; Cryoelectron Microscopy; ERG1 Potassium Channel; HEK293 Cells; Humans; Molecular Docking Simulation; Potassium Channel Blockers; Protein Binding
PubMed: 33450182
DOI: 10.1016/j.str.2020.12.007 -
Journal For Immunotherapy of Cancer Jul 2023Most immunotherapies approved for clinical use rely on the use of recombinant proteins and cell-based approaches, rendering their manufacturing expensive and logistics...
BACKGROUND
Most immunotherapies approved for clinical use rely on the use of recombinant proteins and cell-based approaches, rendering their manufacturing expensive and logistics onerous. The identification of novel small molecule immunotherapeutic agents might overcome such limitations.
METHOD
For immunopharmacological screening campaigns, we built an artificial miniature immune system in which dendritic cells (DCs) derived from immature precursors present MHC (major histocompatibility complex) class I-restricted antigen to a T-cell hybridoma that then secretes interleukin-2 (IL-2).
RESULTS
The screening of three drug libraries relevant to known signaling pathways, FDA (Food and Drug Administration)-approved drugs and neuroendocrine factors yielded two major hits, astemizole and ikarugamycin. Mechanistically, ikarugamycin turned out to act on DCs to inhibit hexokinase 2, hence stimulating their antigen presenting potential. In contrast, astemizole acts as a histamine H1 receptor (H1R1) antagonist to activate T cells in a non-specific, DC-independent fashion. Astemizole induced the production of IL-2 and interferon-γ (IFN-γ) by CD4 and CD8 T cells both in vitro and in vivo. Both ikarugamycin and astemizole improved the anticancer activity of the immunogenic chemotherapeutic agent oxaliplatin in a T cell-dependent fashion. Of note, astemizole enhanced the CD8/Foxp3 ratio in the tumor immune infiltrate as well as IFN-γ production by local CD8 T lymphocytes. In patients with cancer, high H1R1 expression correlated with low infiltration by TH1 cells, as well as with signs of T-cell exhaustion. The combination of astemizole and oxaliplatin was able to cure the majority of mice bearing orthotopic non-small cell lung cancers (NSCLC), then inducing a state of protective long-term immune memory. The NSCLC-eradicating effect of astemizole plus oxaliplatin was lost on depletion of either CD4 or CD8 T cells, as well as on neutralization of IFN-γ.
CONCLUSIONS
These findings underscore the potential utility of this screening system for the identification of immunostimulatory drugs with anticancer effects.
Topics: United States; Mice; Animals; CD8-Positive T-Lymphocytes; Interleukin-2; Astemizole; Oxaliplatin; Immunity, Cellular; Histocompatibility Antigens Class I; Interferon-gamma
PubMed: 37419511
DOI: 10.1136/jitc-2023-006785 -
BMC Chemistry Feb 2021Imidazole is a five-membered heterocyclic moiety that possesses three carbon, two nitrogen, four hydrogen atoms, and two double bonds. It is also known as 1, 3-diazole.... (Review)
Review
Imidazole is a five-membered heterocyclic moiety that possesses three carbon, two nitrogen, four hydrogen atoms, and two double bonds. It is also known as 1, 3-diazole. It contains two nitrogen atoms, in which one nitrogen bear a hydrogen atom, and the other is called pyrrole type nitrogen. The imidazole name was reported by Arthur Rudolf Hantzsch (1857-1935) in 1887. 1, 3-diazole is an amphoteric in nature i.e. it shows both acidic and basic properties. It is a white or colorless solid that is highly soluble in water and other polar solvents. Due to the presence of a positive charge on either of two nitrogen atom, it shows two equivalent tautomeric forms. Imidazole was first named glyoxaline because the first synthesis has been made by glyoxal and ammonia. It is the basic core of some natural products such as histidine, purine, histamine and DNA based structures, etc. Among the different heterocyclic compounds, imidazole is better known due to its broad range of chemical and biological properties. Imidazole has become an important synthon in the development of new drugs. The derivatives of 1, 3-diazole show different biological activities such as antibacterial, antimycobacterial, anti-inflammatory, antitumor, antidiabetic, anti-allergic, antipyretic, antiviral, antioxidant, anti-amoebic, antihelmintic, antifungal and ulcerogenic activities, etc. as reported in the literature. There are different examples of commercially available drugs in the market which contains 1, 3-diazole ring such as clemizole (antihistaminic agent), etonitazene (analgesic), enviroxime (antiviral), astemizole (antihistaminic agent), omeprazole, pantoprazole (antiulcer), thiabendazole (antihelmintic), nocodazole (antinematodal), metronidazole, nitroso-imidazole (bactericidal), megazol (trypanocidal), azathioprine (anti rheumatoid arthritis), dacarbazine (Hodgkin's disease), tinidazole, ornidazole (antiprotozoal and antibacterial), etc. This present review summarized some pharmacological activities and various kinds of synthetic routes for imidazole and their derived products.
PubMed: 33602331
DOI: 10.1186/s13065-020-00730-1 -
Microbial Pathogenesis Jul 2021Since the beginning of December 2019, a novel Coronavirus severe respiratory disease, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) which also...
Since the beginning of December 2019, a novel Coronavirus severe respiratory disease, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) which also been termed 2019-new CoV (2019-nCoV), has continued to spread worldwide. As of August 27, 2020, a total of 24,232,429 people have been infected and 826,518 people have died. In our study, we found that astemizole can antagonize ACE2 and inhibit the entry of SARS-COV-2 spike pseudovirus into ACE2-expressed HEK293T cells (ACE2hi cells). We analysied the binding character of astemizole to ACE2 by molecular docking and surface plasmon resonance (SPR) assays and molecule docking, SARS-COV-2 spike pseudotype virus was also taken to investigate the suppression viropexis effect of astemizole. The results showed that astemizole can bind to the ACE2 receptor and inhibit the invasion of SARS-COV-2 Spike pseudoviruses. Thus astemizole represent potential drug candidates that can be re-used in anti-coronavirus therapies.
Topics: Astemizole; COVID-19; HEK293 Cells; Humans; Molecular Docking Simulation; Pharmaceutical Preparations; Protein Binding; SARS-CoV-2; Spike Glycoprotein, Coronavirus; Virus Internalization
PubMed: 33932547
DOI: 10.1016/j.micpath.2021.104929 -
Chemical Research in Toxicology Feb 2021Electrophilically reactive drug metabolites are implicated in many adverse drug reactions. In this mechanism-termed bioactivation-metabolic enzymes convert drugs into...
Electrophilically reactive drug metabolites are implicated in many adverse drug reactions. In this mechanism-termed bioactivation-metabolic enzymes convert drugs into reactive metabolites that often conjugate to nucleophilic sites within biological macromolecules like proteins. Toxic metabolite-product adducts induce severe immune responses that can cause sometimes fatal disorders, most commonly in the form of liver injury, blood dyscrasia, or the dermatologic conditions toxic epidermal necrolysis and Stevens-Johnson syndrome. This study models four of the most common metabolic transformations that result in bioactivation: quinone formation, epoxidation, thiophene sulfur-oxidation, and nitroaromatic reduction, by synthesizing models of metabolism and reactivity. First, the metabolism models predict the formation probabilities of all possible metabolites among the pathways studied. Second, the exact structures of these metabolites are enumerated. Third, using these structures, the reactivity model predicts the reactivity of each metabolite. Finally, a feedfoward neural network converts the metabolism and reactivity predictions to a bioactivation prediction for each possible metabolite. These bioactivation predictions represent the joint probability that a metabolite forms and that this metabolite subsequently conjugates to protein or glutathione. Among molecules bioactivated by these pathways, we predicted the correct pathway with an AUC accuracy of 89.98%. Furthermore, the model predicts whether molecules will be bioactivated, distinguishing bioactivated and nonbioactivated molecules with 81.06% AUC. We applied this algorithm to withdrawn drugs. The known bioactivation pathways of alclofenac and benzbromarone were identified by the algorithm, and high probability bioactivation pathways not yet confirmed were identified for safrazine, zimelidine, and astemizole. This bioactivation model-the first of its kind that jointly considers both metabolism and reactivity-enables drug candidates to be quickly evaluated for a toxicity risk that often evades detection during preclinical trials. The XenoSite bioactivation model is available at http://swami.wustl.edu/xenosite/p/bioactivation.
Topics: Epoxy Compounds; Humans; Models, Biological; Molecular Structure; Nitrobenzenes; Oxidation-Reduction; Quinones; Sulfur; Thiophenes
PubMed: 33496184
DOI: 10.1021/acs.chemrestox.0c00417 -
Biophysical Journal May 2020High-throughput in vitro drug assays have been impacted by recent advances in human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) technology and by...
High-throughput in vitro drug assays have been impacted by recent advances in human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) technology and by contact-free all-optical systems simultaneously measuring action potentials (APs) and Ca transients (CaTrs). Parallel computational advances have shown that in silico simulations can predict drug effects with high accuracy. We combine these in vitro and in silico technologies and demonstrate the utility of high-throughput experimental data to refine in silico hiPSC-CM populations and to predict and explain drug action mechanisms. Optically obtained hiPSC-CM APs and CaTrs were used from spontaneous activity and under optical pacing in control and drug conditions at multiple doses. An updated version of the Paci2018 model was developed to refine the description of hiPSC-CM spontaneous electrical activity; a population of in silico hiPSC-CMs was constructed and calibrated using simultaneously recorded APs and CaTrs. We tested in silico five drugs (astemizole, dofetilide, ibutilide, bepridil, and diltiazem) and compared the outcomes to in vitro optical recordings. Our simulations showed that physiologically accurate population of models can be obtained by integrating AP and CaTr control records. Thus, constructed population of models correctly predicted the drug effects and occurrence of adverse episodes, even though the population was optimized only based on control data and in vitro drug testing data were not deployed during its calibration. Furthermore, the in silico investigation yielded mechanistic insights; e.g., through simulations, bepridil's more proarrhythmic action in adult cardiomyocytes compared to hiPSC-CMs could be traced to the different expression of ion currents in the two. Therefore, our work 1) supports the utility of all-optical electrophysiology in providing high-content data to refine experimentally calibrated populations of in silico hiPSC-CMs, 2) offers insights into certain limitations when translating results obtained in hiPSC-CMs to humans, and 3) shows the strength of combining high-throughput in vitro and population in silico approaches.
Topics: Action Potentials; Adult; Computer Simulation; Drug Evaluation; Humans; Induced Pluripotent Stem Cells; Myocytes, Cardiac
PubMed: 32298635
DOI: 10.1016/j.bpj.2020.03.018 -
International Journal of Molecular... Sep 2022Despite the significant progress made towards comprehending the deregulated signatures in lung cancer, these vary from study to study. We reanalyzed 25 studies from the...
Despite the significant progress made towards comprehending the deregulated signatures in lung cancer, these vary from study to study. We reanalyzed 25 studies from the Gene Expression Omnibus (GEO) to detect and annotate co-deregulated signatures in lung cancer and in single-gene or single-drug perturbation experiments. We aimed to decipher the networks that these co-deregulated genes (co-DEGs) form along with their upstream regulators. Differential expression and upstream regulators were computed using Characteristic Direction and Systems Biology tools, including GEO2Enrichr and X2K. Co-deregulated gene expression profiles were further validated across different molecular and immune subtypes in lung adenocarcinoma (TCGA-LUAD) and lung adenocarcinoma (TCGA-LUSC) datasets, as well as using immunohistochemistry data from the Human Protein Atlas, before being subjected to subsequent GO and KEGG enrichment analysis. The functional alterations of the co-upregulated genes in lung cancer were mostly related to immune response regulating the cell surface signaling pathway, in contrast to the co-downregulated genes, which were related to S-nitrosylation. Networks of hub proteins across the co-DEGs consisted of overlapping TFs (SOX2, MYC, KAT2A) and kinases (MAPK14, CSNK2A1 and CDKs). Furthermore, using Connectivity Map we highlighted putative repurposing drugs, including valproic acid, betonicine and astemizole. Similarly, we analyzed the co-DEG signatures in single-gene and single-drug perturbation experiments in lung cancer cell lines. In summary, we identified critical co-DEGs in lung cancer providing an innovative framework for their potential use in developing personalized therapeutic strategies.
Topics: Adenocarcinoma of Lung; Astemizole; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Mitogen-Activated Protein Kinase 14; Transcription Factors; Valproic Acid
PubMed: 36142846
DOI: 10.3390/ijms231810933 -
Methods in Molecular Biology (Clifton,... 2022Human ether-a-go-go-related gene (hERG) channel plays an essential role in the repolarization of the cardiac action potential. Genetic mutations and some chemicals/drugs...
Human ether-a-go-go-related gene (hERG) channel plays an essential role in the repolarization of the cardiac action potential. Genetic mutations and some chemicals/drugs interfere with hERG channel activity, which may prolong the QT interval and potentially cause long QT syndrome. The FluxOR™ thallium flux assay performed in two cell lines, U2OS and HEK293, with stable hERG expression can be used to identify compounds that inhibit hERG channel activity. This chapter describes a cell-based hERG channel inhibition assay that has been optimized and performed in a 1536-well plate format. The homogeneous and robust assay can be used to identify compounds that inhibit hERG channel activity.
Topics: Action Potentials; Ether-A-Go-Go Potassium Channels; HEK293 Cells; Humans; Long QT Syndrome; Research Design
PubMed: 35294752
DOI: 10.1007/978-1-0716-2213-1_3 -
The Journal of Pharmacology and... Aug 2022Infigratinib (INF) is a fibroblast growth factor receptor inhibitor that was recently United States Food and Drug Administration-approved for the treatment of advanced...
Identification of Infigratinib as a Potent Reversible Inhibitor and Mechanism-Based Inactivator of CYP2J2: Nascent Evidence for a Potential In Vivo Metabolic Drug-Drug Interaction with Rivaroxaban.
Infigratinib (INF) is a fibroblast growth factor receptor inhibitor that was recently United States Food and Drug Administration-approved for the treatment of advanced or metastatic cholangiocarcinoma. We previously established that INF inhibited and inactivated cytochrome P450 3A4 (CYP3A4). Here, in a follow up to our previous study, we identified for the first time that INF also elicited potent competitive inhibition and mechanism-based inactivation of CYP2J2 with kinetic parameters , , , and a partition ratio of 1.94 M, 0.10 M, 0.026 minute, and ∼3, respectively, when rivaroxaban was harnessed as the probe substrate. Inactivation was revealed to exhibit cofactor-dependency and was attenuated by an alternative substrate (astemizole) and direct inhibitor (nilotinib) of CYP2J2. Additionally, the nature of inactivation was unlikely to be pseudo-irreversible and instead arose from covalent modification due to the lack of substantial enzyme activity recovery after dialysis and chemical oxidation, as well as the lack of a resolvable Soret band in spectral scans. Glutathione trapping confirmed that the identity of the putative reactive intermediate implicated in the covalent inactivation of both CYP2J2 and CYP3A4 was identical and likely attributable to an electrophilic -benzoquinonediimine intermediate of INF. Finally, mechanistic static modeling revealed that by integrating the previously arcane inhibition and inactivation kinetic parameters of CYP2J2-mediated rivaroxaban hydroxylation by INF illuminated in this work, together with those previously documented for CYP3A4, a 49% increase in the systemic exposure of rivaroxaban was projected. Our modeling results predicted a potential risk of metabolic drug-drug interactions between the clinically relevant combination of rivaroxaban and INF in the setting of cancer. SIGNIFICANCE STATEMENT: This study reported that INF elicits potent reversible inhibition and mechanism-based inactivation of CYP2J2. Furthermore, static modelling predicted that its coadministration with the direct oral anticoagulant rivaroxaban may potentially culminate in a metabolic drug-drug interaction (DDI) leading to an increased risk of major bleeding. As rivaroxaban is steadily gaining prominence as the anticoagulant of choice in the treatment of cancer-associated venous thromboembolism, the DDI projections reported here are clinically relevant and warrant further investigation via physiologically based pharmacokinetic modelling and simulation.
Topics: Anticoagulants; Cytochrome P-450 CYP2J2; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Drug Interactions; Phenylurea Compounds; Pyrimidines; Rivaroxaban
PubMed: 35640957
DOI: 10.1124/jpet.122.001222 -
Genes Jan 2020Retinoblastoma is the most common pediatric intraocular malignant tumor. Unfortunately, low cure rates and low life expectancy are observed in low-income countries....
Retinoblastoma is the most common pediatric intraocular malignant tumor. Unfortunately, low cure rates and low life expectancy are observed in low-income countries. Thus, alternative therapies are needed for patients who do not respond to current treatments or those with advanced cases of the disease. (Eag1) is a voltage-gated potassium channel involved in cancer. expression is upregulated by the human papilloma virus (HPV) oncogene E7, suggesting that retinoblastoma protein (pRb) may regulate . Astemizole is an antihistamine that is suggested to be repurposed for cancer treatment; it targets proteins implicated in cancer, including histamine receptors, ATP binding cassette transporters, and Eag channels. Here, we investigated Eag1 regulation using pRb and Eag1 expression in human retinoblastoma. The effect of astemizole on the cell proliferation of primary human retinoblastoma cultures was also studied. HeLa cervical cancer cells (HPV-positive and expressing Eag1) were transfected with . mRNA expression was studied using qPCR, and protein expression was assessed using western blotting and immunochemistry. Cell proliferation was evaluated with an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. transfection down-regulated Eag1 mRNA and protein expression. The human retinoblastoma samples displayed heterogeneous Eag1 mRNA and protein expression. Astemizole decreased cell proliferation in primary retinoblastoma cultures. Our results suggest that Eag1 mRNA and protein expression was regulated by pRb in vitro, and that human retinoblastoma tissues had heterogeneous Eag1 mRNA and protein expression. Furthermore, our results propose that the multitarget drug astemizole may have clinical relevance in patients with retinoblastoma, for instance, in those who do not respond to current treatments.
Topics: Astemizole; Cell Line, Tumor; Cell Proliferation; Child, Preschool; Ether-A-Go-Go Potassium Channels; Female; Gene Expression Regulation, Neoplastic; HeLa Cells; Humans; Infant; Male; Oncogenes; RNA, Messenger; Retinal Neoplasms; Retinoblastoma; Retinoblastoma Protein; Transfection
PubMed: 31973216
DOI: 10.3390/genes11020119