Drug Repurposing Approach for Developing Novel Therapy Against Mupirocin-Resistant Staphylococcus aureus

Structure and dynamic simulation-based interactions of benzenoids, pyrroles and organooxygen compounds for effective targeting of GPX4 in ischemic stroke

The discovery of a novel drug for ischemic stroke is plagued by expensive and unsuccessful outcomes. FDA-approved drugs could be a viable repurposing strategy for stroke therapy. Emerging evidence suggests the regulating role of Glutathione peroxidase (GPX4) in stroke and attracts as a potential target. To overcome limited therapeutic interventions, a drug repurposing in silico investigation of FDA-approved drugs is proposed for the GPX4 receptor in distinctive species (Homo sapiens and Mus musculus). The GPX4 UniProt wild type ids, that is, P36969 (Homo sapiens), P36970 (Rattus norvegicus) and O70325 (Mus musculus) are Swiss modelled, and resultant templates are 2OBI and 6HN3 for Homo sapiens, and 5L71 for Mus musculus with a sequence identity of ∼88%. Enrichment analysis reveals high sensitivity and ranked actives with ROC and AUC values of 0.59 and 0.61, respectively. Virtual screening at extra precision resulted hit Acarbosum, is similar between 2OBI and 6HN3, demonstrating a multiple-target specificity and Iopromide, targeting 2OBI. MD simulation at 100 ns following trajectory analysis provides RMSD (∼1.2-1.8Å), RMSF (∼1.6-2.7Å), Rgyr (∼15-15.6Å) depicting stabilisation of receptor-ligand complexes. Furthermore, average B-factor value of 2OBI, 6HN3 and 5L71 is 25Å, 24Å and 60Å with a defined resolution of 1.55Å, 1.01Å and 1.80Å, respectively, depicting the thermodynamic stability of the protein structures. The dynamic cross-correlation and principal component analysis of residual fluctuations reveal more positive correlation, high atomic displacements and greater residual clustering of residues from atomic coordinates. Therefore, Acarbosum, an FDA-approved drug, could act as a potential repurposing drug with a multi-target approach translating from preclinical to clinical stages.Communicated by Ramaswamy H. Sarma.

In Vitro and In Silico Investigation of BCI Anticancer Properties and Its Potential for Chemotherapy-Combined Treatments

BACKGROUND

DUSP6 phosphatase serves as a negative regulator of MAPK kinases involved in numerous cellular processes. BCI has been identified as a potential allosteric inhibitor with anticancer activity. Our study was designed to test the anticancer properties of BCI in colon cancer cells, to characterize the effect of this compound on chemotherapeutics such as irinotecan and oxaliplatin activity, and to identify potential molecular targets for this inhibitor.

METHODS

BCI cytotoxicity, proapoptotic activity, and cell cycle distribution were investigated in vitro on three colon cancer cell lines (DLD1, HT-29, and Caco-2). In silico investigation was prepared to assess BCI drug-likeness and identify potential molecular targets.

RESULTS

The exposure of colorectal cancer cells with BCI resulted in antitumor effects associated with cell cycle arrest and induction of apoptosis. BCI exhibited strong cytotoxicity on DLD1, HT-29, and Caco-2 cells. BCI showed no significant interaction with irinotecan, but strongly attenuated the anticancer activity of oxaliplatin when administered together. Analysis of synergy potential further confirmed the antagonistic interaction between these two compounds. In silico investigation indicated CDK5 as a potential new target of BCI.

CONCLUSIONS

Our studies point to the anticancer potential of BCI but note the need for a precise mechanism of action.

Quinoline derivatives volunteering against antimicrobial resistance: rational approaches, design strategies, structure activity relationship and mechanistic insights

Emergence of antimicrobial resistance has become a great threat to human species as there is shortage of development of new antimicrobial agents. So, its mandatary to combat AMR by initiating research and developing new novel antimicrobial agents. Among phytoconstituents, Quinoline (nitrogen containing heterocyclic) have played a wide role in providing new bioactive molecules. So, this review provides rational approaches, design strategies, structure activity relationship and mechanistic insights of newly developed quinoline derivatives as antimicrobial agents.

Recent Advancement in Breast Cancer Research: Insights from Model Organisms-Mouse Models to Zebrafish

Animal models have been utilized for decades to investigate the causes of human diseases and provide platforms for testing novel therapies. Indeed, breakthrough advances in genetically engineered mouse (GEM) models and xenograft transplantation technologies have dramatically benefited in elucidating the mechanisms underlying the pathogenesis of multiple diseases, including cancer. The currently available GEM models have been employed to assess specific genetic changes that underlay many features of carcinogenesis, including variations in tumor cell proliferation, apoptosis, invasion, metastasis, angiogenesis, and drug resistance. In addition, mice models render it easier to locate tumor biomarkers for the recognition, prognosis, and surveillance of cancer progression and recurrence. Furthermore, the patient-derived xenograft (PDX) model, which involves the direct surgical transfer of fresh human tumor samples to immunodeficient mice, has contributed significantly to advancing the field of drug discovery and therapeutics. Here, we provide a synopsis of mouse and zebrafish models used in cancer research as well as an interdisciplinary 'Team Medicine' approach that has not only accelerated our understanding of varied aspects of carcinogenesis but has also been instrumental in developing novel therapeutic strategies.

In-Silico Design, Synthesis, and Pharmacological Evaluation of Oxadiazole-Based Selective Cyclo-oxygenase-2 Inhibitors

A series of oxadiazole-based five-membered heterocyclic derivatives was designed and synthesized with the intent of exclusive cyclo-oxygenase-2 (COX-2) inhibition to acquire anti-inflammatory activity without the presence of gastric toxicity. Oxadiazole-based novel analogs were designed by using bioisosteric substitutions and were screened against the macromolecular target by using docking-based virtual screening to identify their potential inhibitors. These selective COX-2 inhibitors were further evaluated for their stability within the binding cavity of macromolecular complex by performing molecular dynamic simulation for 100 ns. Selected compounds were synthesized by using Naphthalene-2-yl-acetic acid as a starting material based on the fundamental structure of naphthalene. The naphthalene ring and methylene bridge of naphthalene-2-yl-acetic acid were retained in the rational molecular design by replacing the carboxyl group with biologically significant groups like 1,3,4-oxadiazoles, with the goal of obtaining a novel, superior, and relatively safe anti-inflammatory molecule with better efficacy and optimized pharmacokinetics. Anti-inflammatory as well as analgesic properties of the compounds were evaluated experimentally for their pharmacological efficiency.

Discovery of adapalene and dihydrotachysterol as antiviral agents for the Omicron variant of SARS-CoV-2 through computational drug repurposing

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been significantly paralyzing the societies, economies and health care systems around the globe. The mutations on the genome of SARS-CoV-2 led to the emergence of new variants, some of which are classified as "variant of concern" due to their increased transmissibility and better viral fitness. The Omicron variant, as the latest variant of concern, dominated the current COVID-19 cases all around the world. Unlike the previous variants of concern, the Omicron variant has 15 mutations on the receptor-binding domain of spike protein and the changes in the key amino acid residues of S protein can enhance the binding ability of the virus to hACE2, resulting in a significant increase in the infectivity of the Omicron variant. Therefore, there is still an urgent need for treatment and prevention of variants of concern, particularly for the Omicron variant. In this study, an in silico drug repurposing was conducted through the molecular docking of 2890 FDA-approved drugs against the mutant S protein of SARS-CoV-2 for Omicron variant. We discovered promising drug candidates for the inhibition of alarming Omicron variant such as quinestrol, adapalene, tamibarotene, and dihydrotachysterol. The stability of ligands complexed with the mutant S protein was confirmed using MD simulations. The lead compounds were further evaluated for their potential use and side effects based on the current literature. Particularly, adapalene, dihydrotachysterol, levocabastine and bexarotene came into prominence due to their non-interference with the normal physiological processes. Therefore, this study suggests that these approved drugs can be considered as drug candidates for further in vitro and in vivo studies to develop new treatment options for the Omicron variant of SARS-CoV-2.

Computational Design of Plant-Based Antistress Agents Targeting Nociceptin Receptor

Stress is the body's reaction to the challenges it faces, and it produces a multitude of chemical molecules known as stressors as a result of these reactions. It's also a misalignment of the sympathetic and parasympathetic nervous systems causing changes in a variety of physiological reactions and perhaps leading to stress disorders. The reduction in neurotransmitter & neurohormonal hormones is mainly governed by the nociceptin receptor as G-protein coupled receptor and increased the level of reactive oxygen species. Various synthetic medicines that target nociceptin receptors were utilized to reduce the effects of stress but they come up with a variety of side effects. Because of the widespread utilization and renewed interest in medicinal herbal plants considered to be alternative antistress therapy. Our present work is an approach to decipher the molecular nature of novel herbal leads by targeting nociceptin receptor, under which herbal compounds were screened and validated through in-silico methods. Among screened leads, withanolide-B showed stable association in the active site of the nociceptin receptor as an antistress agent with no side effects. Furthermore, the selected lead was also evaluated for stability by molecular dynamic stimulation as well as for pharmacokinetics and toxicity profile. It has been concluded stable conformation of withanolide-B without presence of any major toxic effects. As a result, the in silico molecular docking technique is a highly successful method for selecting a prospective herbal lead molecule with respect to a specific target, and future research can pave the way for further exploration in the drug development field.

Computational Bioprospecting Guggulsterone against ADP Ribose Phosphatase of SARS-CoV-2

Coronavirus Disease-2019 (COVID-19) is a highly contagious disease caused by Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2). The World Health Organization (WHO) classified the disease a as global public health hazard on 11 March 2020. Currently, there are no adequate measures to combat viral infections, including COVID-19, and the medication guidelines for the management of COVID-19 are dependent on previous findings from SARS-CoV and MERS-CoV research. Natural products have achieved widespread acceptance around the world as a means of enhancing healthcare and disease prevention. Plants are a potential source of antiviral factors such as flavonoids, phenolic acids, terpenoids, and others. Some of these agents exhibit a broad spectrum of antiviral activity. This study aimed to screen herbal leads for possible inhibitors of the SARS-CoV-2 ADP Ribose Phosphatase enzyme (ARP). Guggulsterone was found to be highly stabilized within the active site of the viral ARP enzyme by molecular dynamic simulation with very little fluctuation throughout the simulation timeframe of 100 ns. Thus, guggulsterone can be further used to develop a safe and competent medication for evolving therapy against SARS-CoV-2 in post-preclinical and clinical trials.

Computational Design, Synthesis, and Pharmacological Evaluation of Naproxen-Guaiacol Chimera for Gastro-Sparing Anti-Inflammatory Response by Selective COX2 Inhibition

The 4-allyl guaiacol is a natural phenolic molecule that has been widely studied for its antioxidant capacity against reactive-oxygen-species-mediated cellular damage. Therefore, we hypothesized that concomitant use of an antioxidant and NSAID may decrease the risk of gastrointestinal toxicity and make the therapy safer. To address the gastrointestinal toxicity of conventional NSAIDs, a new S-naproxen-4-allyl guaiacol chimera (MAS-1696) was computationally developed, chemically synthesized, and tested for anti-inflammatory effectiveness and gastrointestinal safety. The inhibitory potency of MAS-1696 tested against cyclooxygenase-2 (COX2), 15-lipoxygenase-2 (15-LOX2), and lipoxygenase-5 (5-LOX) in vitro revealed a stronger inhibition of COX2. Furthermore, the MAS-1696 chimera increased the COX selectivity index by 23% as compared to the parent compound naproxen, implying higher efficacy and gastric safety. In vivo data showed that MAS-1696 was less likely to cause gastrointestinal harm than naproxen while also exerting anti-inflammatory and analgesic effects equivalent to or superior to naproxen. In conclusion, MAS-1696 is orally active, bio-labile, and crystalline, making it a medication that may be administered orally.

Computational Design of Phosphatidylinositol 3-Kinase Inhibitors

One of the most sought-after therapeutic targets for treating human cancers is the phosphoinositide 3-kinase; PI3k is an integral part of the PI3K/protein kinase B signaling arcade. This pathway is frequently activated in malignancies. Drug resistance and dose-limiting adverse effects are currently associated challenges with the existing anticancer chemotherapy. Therefore, in this research, a series of pyrimidine derivatives were designed and evaluated against human PI3K by using molecular docking analysis. The docking results were further verified by molecular dynamic simulation, which analyzed the strength of the macromolecular complex with respect to time. Compounds IV and XIV were found to be the most potent inhibitors of the human PI3K receptor with a high degree of stability within the active site of the target receptor for a timeframe of 50 ns. Thus, both of these compounds could be important drug candidates for the development of PI3K inhibitors as a prospective anticancer agent.

Repurposing benzbromarone as antifolate to develop novel antifungal therapy for Candida albicans

Fungal infections in humans are responsible for mild to severe infections resulting in systemic effects that cause a large amount of mortality. Invasive fungal infections are having similar symptomatic effects to those of COVID-19. The COVID-19 patients are immunocompromised in nature and have a high probability of developing severe fungal infections, resulting in the development of further complications. The existing antifungal therapy has associated problems related to the development of drug resistance, being sub-potent in nature, and the presence of undesirable toxic effects. The fungal dihydrofolate reductase is an essential enzyme involved in the absorption of dietary folic acid and its conversion into tetrahydrofolate, which is a coenzyme required for the biosynthesis of the fungal nucleotides. Thus, in the current study, an attempt has been made to identify potential folate inhibitors of Candida albicans by a computational drug repurposing approach. Based upon the molecular docking simulation-based virtual screening followed by the molecular dynamic simulation of the macromolecular complex, benzbromarone has been identified as a potential anti-folate agent for the development of a novel therapy for the treatment of candidiasis.

Preparation of Novel Pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine Sulfonamides and Their Experimental and Computational Biological Studies

Pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides constitute a novel class of heterocyclic compounds with broad biological activity, including anticancer properties. Investigated in this study, MM-compounds (MM134, MM136, MM137, and MM139) exhibited cytotoxic and proapoptotic activity against cancer cell lines (BxPC-3, PC-3, and HCT-116) in nanomolar concentrations without causing cytotoxicity in normal cells (L929 and WI38). In silico predictions indicate that tested compounds exhibit favorable pharmacokinetic profiles and may exert anticancer activity through the inhibition of BTK kinase, the AKT-mTOR pathway and PD1-PD-L1 interaction. Our findings point out that these sulfonamide derivatives may constitute a source of new anticancer drugs after optimization.

In silico evaluation of food-derived carotenoids against SARS-CoV-2 drug targets: Crocin is a promising dietary supplement candidate for COVID-19

The current COVID‐19 pandemic is severely threatening public healthcare systems around the globe. Some supporting therapies such as remdesivir, favipiravir, and ivermectin are still under the process of a clinical trial, it is thus urgent to find alternative treatment and prevention options for SARS‐CoV‐2. In this regard, although many natural products have been tested and/or suggested for the treatment and prophylaxis of COVID‐19, carotenoids as an important class of natural products were underexplored. The dietary supplementation of some carotenoids was already suggested to be potentially effective in the treatment of COVID‐19 due to their strong antioxidant properties. In this study, we performed an in silico screening of common food‐derived carotenoids against druggable target proteins of SARS‐CoV‐2 including main protease, helicase, replication complex, spike protein and its mutants for the recent variants of concern, and ADP‐ribose phosphatase. Molecular docking results revealed that some of the carotenoids had low binding energies toward multiple receptors. Particularly, crocin had the strongest binding affinity (−10.5 kcal/mol) toward the replication complex of SARS‐CoV‐2 and indeed possessed quite low binding energy scores for other targets as well. The stability of crocin in the corresponding receptors was confirmed by molecular dynamics simulations. Our study, therefore, suggests that carotenoids, especially crocin, can be considered an effective alternative therapeutics and a dietary supplement candidate for the prophylaxis and treatment of SARS‐CoV‐2.

In silico bioprospecting of taraxerol as a main protease inhibitor of SARS-CoV-2 to develop therapy against COVID-19

COVID-19 was caused by a novel coronavirus known as SARS-CoV-2. The COVID-19 disease outbreak has been avowed as a global pandemic by the World Health Organization at the end of March 2020. It leads to the global economic crash, resulting in the starvation of a large population belonging to economically backward countries. Hence, the development of an alternative medicine along with the vaccine is of the utmost importance for the management of COVID-19. Therefore, screening of several herbal leads was performed to explore their potential against SARS-CoV-2. Furthermore, viral main protease was selected as a key enzyme for performing the study. Various computational approaches, including molecular docking simulation, were used in the current study to find potential inhibitors of viral main protease from a library of 150 herbal leads. Toxicity and ADME prediction of selected molecules were also analysed by Osiris molecular property explorer software. Molecular dynamic simulation of the top 10 docked herbal leads was analysed for stability using 100 ns. Taraxerol (−10.17 kcal/mol), diosgenin (10.12 kcal/mol), amyrin (−9.56 kcal/mol), and asiaticoside (−9.54 kcal/mol) were among the top four herbal leads with the highest binding affinity with the main protease enzyme. Thus, taraxerol was found to be an effective drug candidate against the main protease enzyme for the management of COVID-19. Furthermore, its clinical effect and safety profile need to be established through an in vivo model.

The crafty opponent: the defense systems of Staphylococcus aureus and response measures

Staphylococcus aureus is a serious threat to public health. S. aureus infection can cause acute or long-term persistent infections that are often resistant to antibiotics and are associated with high morbidity and death. Understanding the defensive systems of S. aureus can help clinicians make the best use of antimicrobial drugs and can also help with antimicrobial stewardship. The mechanisms and clinical implications of S. aureus defense systems, as well as potential response systems, were discussed in this study. Because resistance to all currently available antibiotics is unavoidable, new medicines are always being developed. Alternative techniques, such as anti-virulence and bacteriophage therapies, are being researched and may become major tools in the fight against staphylococcal infections in the future, in addition to the development of new small compounds that affect cell viability.

The promising anti-virulence activity of candesartan, domperidone, and miconazole on Staphylococcus aureus

Staphylococcus aureus is a primary cause of hospital and community-acquired infections. With the emergence of multidrug-resistant S. aureus strains, there is a need for new drugs discovery. Due to the poor supply of new antimicrobials, targeting virulence of S. aureus may generate weaker selection for resistant strains, anti-virulence agents disarm the pathogen instead of killing it. In this study, the ability of the FDA-approved drugs domperidone, candesartan, and miconazole as inhibitors of S. aureus virulence was investigated. The effect of tested drugs was evaluated against biofilm formation, lipase, protease, hemolysin, and staphyloxanthin production by using phenotypic and genotypic methods. At sub-inhibitory concentrations, candesartan, domperidone, and miconazole showed a significant inhibition of hemolysin (75.8-96%), staphyloxanthin (81.2-85%), lipase (50-65%), protease (40-64%), and biofilm formation (71.4-90%). Domperidone and candesartan have similar activity and were more powerful than miconazole against S. aureus virulence. The hemolysins and lipase inhibition were the greatest under the domperidone effect. Candesartan showed a remarkable reduction in staphyloxanthin production. The highest inhibitory effect of proteolytic activity was obtained with domperidone and candesartan. Biofilm was significantly reduced by miconazole. Expression levels of crtM, sigB, sarA, agrA, hla, fnbA, and icaA genes were significantly reduced under candesartan (68.98-82.7%), domperidone (62.6-77.2%), and miconazole (32.96-52.6%) at sub-MIC concentrations. Candesartan showed the highest inhibition activity against crtM, sigB, sarA, agrA, hla, and icaA expression followed by domperidone then miconazole. Domperidone showed the highest downregulation activity against fnbA gene. In conclusion, candesartan, domperidone, and miconazole could serve as anti-virulence agents for attenuation of S. aureus pathogenicity.

Computational repurposing of tamibarotene against triple mutant variant of SARS-CoV-2

The outbreak of the triple mutant strain of severe acute respiratory syndrome coronavirus-2 (SARS-COV-2) was more virulent and pathogenic than its original strain. The viral triple mutant strain of SARS-COV-2 is extremely adaptive and increases penetrability into the host. The triple mutant viral strain was first reported in Brazil and South Africa and then communicated to different countries responsible for the second wave of the coronavirus disease (COVID-19) global pandemic with a high mortality rate. The reported genomic mutations are responsible for the alterations in the viral functional and structural proteins, causing the ineffectiveness of the existing antiviral therapy targeting these proteins. Thus, in current research, molecular docking simulation-based virtual screening of a ligand library consisting of FDA-approved existing drugs followed by molecular dynamics simulation-based validation of leads was performed to develop a potent inhibitor molecule for the triple mutant viral strain SARS-CoV-2. Based on the safety profile, tamibarotene was selected as a safe and effective drug candidate for developing therapy against the triple mutant viral spike protein of SARS-CoV-2.

Computational Drug Repurposing Approach to Identify Potential Fatty Acid-Binding Protein-4 Inhibitors to Develop Novel Antiobesity Therapy

Obesity is a chronic human disorder caused by multiple factors, causing excessive accumulation of fat because of the disparity in take of energy intake with respect to its expenditure. Genetic, environmental, and behavioral factors are having a crucial role in its pathogenesis. Fatty acid-binding protein (FABP) is a superfamily that was involved in the transportation, metabolism, and storage of lipids. The experimental studies have revealed that there is a significant rise in the fatty acid-binding protein-4 (FABP4) expression, and plasma concentration in obese and its downregulation or inhibition can be a potential drug target for obesity. Repurposing of drugs is a trending method for the identification of the newer pharmacological action of an established drug molecule having initially approved indication. It is a cost-effective and economical approach for the development of alternative therapies for existing dreadful diseases in quick succession. Thus, the in silico drug repurposing technique is a highly effective approach for identifying an existing drug molecule having an antiobesity therapeutic activity against the human FABP4, and Floxacillin was selected as safe and effective drug for candidates for developing an antiobesity therapy.

Repurposing metocurine as main protease inhibitor to develop novel antiviral therapy for COVID-19

The outbreak of severe acute respiratory syndrome coronavirus-2 is causing a serious disaster through coronavirus disease-19 (COVID-19) around the globe. A large segment of the population from every corner of the world is already infected with this dreadful pathogen with a high mortality rate. These numbers are increasing drastically causing a situation of a global pandemic. Although after the continuous scientific efforts, we are still not having any specific drug or vaccine for the SARS-CoV-2 pathogen to date and there is an urgent need to develop a newer therapy to counter the COVID-19 global pandemic. Thus, in the current study, a framework for computational drug repurposing is established, and based on their safety profile, metocurine was chosen as a safe and effective drug candidate for developing therapy against the viral Mpro enzyme of SARS-CoV-2 for the treatment of COVID-19.

Computational Design and Biological Depiction of Novel Naproxen Derivative

Naproxen (NAP) is one of the commonly used nonselective Cycloxygenase (COX) inhibitors. It is a choice of drug for anti-inflammatory activity by subsiding the generation of the inflammatory components called prostaglandins. The common problem associated with the NAP is gastrointestinal toxicity. It may cause ulceration or stomach bleeding. In this study, the different derivatives of NAP were designed by using phytophenols with the aim that they exert the antioxidant activity and have the potential to reduce ulcer formation. The lead molecules were designed by molecular docking-based virtual screening against human COX-2 enzyme through AutoDock. Then these derivatives were screened for pharmacokinetic profiling by considering Lipinski's filter. The potent and safe molecule was identified by pharmacokinetics and toxicity evaluation. The potent compound was synthesized in the laboratory, purified, characterized, and its pharmacological activities were evaluated. The resultant compound was found to be equipotent and less toxic than the parent compound.