Quest for selective MMP9 inhibitors: a computational approach.

Matrix Metalloproteinases-9 (MMP-9) is one of the important targets that play a vital role in various diseases such as cancer, Alzheimer's, arthritis, etc. Traditionally, MMP-9 inhibitors have been unable to achieve selectivity to get around this target; thereby, novel mechanisms such as inhibition of activated MMP-9 zymogen (pro-MMP-9) have been discovered. The JNJ0966 was one of the few compounds that attained the requisite selectivity by inhibiting the activation of MMP-9 zymogen (pro-MMP-9). Since JNJ0966, no other small molecules have been identified. Herein, extensive in silico studies were called upon to bolster the prospect of exploring potential candidates. The key objective of this research is to identify the potential hits from the ChEMBL database via molecular docking and dynamics approach. Protein with PDB ID: 5UE4, having a unique inhibitor in an allosteric binding pocket of MMP-9, was chosen for the study. Structure-based virtual screening and MMGBSA binding affinity calculations were performed, and five potential hits were finalized. Detailed analysis of the best-scoring molecules was performed with ADMET analysis and molecular dynamics (MD) simulation. All five hits outperformed JNJ0966 in the docking assessment, ADMET analysis, and molecular dynamics simulation. Accordingly, our research findings imply that these hits can be investigated for in vitro and in vivo studies against proMMP9 and might be explored as potential anticancer drugs. The outcome of our research might contribute in expediting the exploration of drugs that inhibits proMMP-9.Communicated by Ramaswamy H. Sarma.

Coumarin and Piperazine Conjugates as Selective Inhibitors of the Tumor-associated Carbonic Anhydrase IX and XII Isoforms.

BACKGROUND: Carbonic Anhydrases (CAs) are a family of metalloenzymes that catalyze the reversible interconversion of CO2 and water to bicarbonate and proton. CA isoforms I, II, IX, and XII are considered physiologically and pharmacologically relevant. OBJECTIVE: The objective of this study is to synthesize potent and selective tumor-associated CA IX and XII inhibitors. METHODS: A library of 17 coumarin derivatives clubbed with piperazine and benzyl moiety was designed, synthesized and evaluated for its inhibitory effects and selectivity profile towards physiologically and pharmacologically relevant CA isoforms I, II, IX, and XII. RESULTS: All the derivatives were found to be active against the tumor-associated isoforms IX and XII. The most active compound against hCA (human Carbonic Anhydrase) IX was found to possess a Ki of 229 nM, while the one against hCA XII had a Ki of 294.2 nM. Additionally, two of the compounds were found to have exquisite selectivity towards the off-target hCA I and II isoforms. Moreover, they were found to be approximately 20-fold more selective towards hCA IX than XII. The selectivity of the compounds was further investigated via molecular modeling techniques. CONCLUSION: Coumarin-piperazine hybrids were identified as potent and selective CA IX and XII inhibitors. Molecular modeling techniques provided interesting cues pertaining to observed selectivity.

Chitosan based architectures as biomedical carriers.

In the recent past, chitosan demonstrated intriguing applications in the different domains of biomedical science, probably due to its biodegradability, biocompatibility, minimal toxicity, cost-effectiveness, and easy-going synthetic procedures. Chitosan is the second most prevalent amino polysaccharide after cellulose, generated from a deacetylated version of chitin. This short review briefly explains the preparation methods for chitosan from chitin and its role as a drug carrier for biomedical applications.

Drug repurposing against SARS-CoV-2 using computational approaches.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has generated a critical need for treatments to reduce morbidity and mortality associated with this disease. However, traditional drug development takes many years, which is not practical solution given the current pandemic. Therefore, a viable option is to repurpose existing drugs. The structural data of several proteins vital for the virus became available shortly after the start of the pandemic. In this review, we discuss the importance of these targets and their available potential inhibitors predicted by the computational approaches. Among the hits identified by computational approaches, 35 candidates were suggested for further evaluation, among which ten drugs are in clinical trials (Phase III and IV) for treating Coronavirus 2019 (COVID-19).

MEMES: Machine learning framework for Enhanced MolEcular Screening.

In drug discovery applications, high throughput virtual screening exercises are routinely performed to determine an initial set of candidate molecules referred to as "hits". In such an experiment, each molecule from a large small-molecule drug library is evaluated in terms of physical properties such as the docking score against a target receptor. In real-life drug discovery experiments, drug libraries are extremely large but still there is only a minor representation of the essentially infinite chemical space, and evaluation of physical properties for each molecule in the library is not computationally feasible. In the current study, a novel Machine learning framework for Enhanced MolEcular Screening (MEMES) based on Bayesian optimization is proposed for efficient sampling of the chemical space. The proposed framework is demonstrated to identify 90% of the top-1000 molecules from a molecular library of size about 100 million, while calculating the docking score only for about 6% of the complete library. We believe that such a framework would tremendously help to reduce the computational effort in not only drug-discovery but also areas that require such high-throughput experiments.

Non-carbohydrate strategies to inhibit lectin proteins with special emphasis on galectins.

Lectins are a family of glycan-binding proteins, many of which have been established as key targets for therapeutic intervention. They play a central role in many physiological and cellular processes. With the advances in protein crystallography, NMR spectroscopy and computational power over the past couple of decades, the carbohydrate-receptor interactions are now well understood and characterized. Nevertheless, designing efficient carbohydrate inhibitors is a laborious endeavour. They are known to have weak affinities, unsuitable pharmacokinetic properties and highly cumbersome/complex synthetic routes. To circumvent these issues many non-carbohydrate strategies have been reported. Galectins are a sub-family of lectin proteins which have been recognized as crucial targets for a wide variety of diseases. Many candidates targeting galectins are currently in advanced stages of clinical trials. There have been a few reports of non-carbohydrate inhibitors targeting galectins which comprise of peptide-based inhibitors and a recent flourish of heterocyclic inhibitors. In this review, we have briefly highlighted the strategies like fragment-based drug-design and high-throughput screens utilized to identify non-carbohydrate based antagonists for proteins wherein the presence of a sugar was believed to be essential. Additionally, we have described the literature pertaining to non-carbohydrate inhibitors of galectins and how previous reports on rational substitution of a sugar motif could aid in design of heterocyclics that inhibit lectins/galectins. We have concluded with remarks on challenges, gap in our understanding and future perspectives concerned with rational design of non-carbohydrate molecules targeting lectins/galectins.

An updated patent review of galectin-1 and galectin-3 inhibitors and their potential therapeutic applications (2016-present).

INTRODUCTION: Galectins are ubiquitous in nature. They have established themselves as a protein family of high therapeutic potential and play a role in a wide variety of diseases like cancer, fibrosis, and Alzheimer's. Within the galectin family, galectin- 1 and galectin- 3 have been widely studied and their roles and functions have now been well established. AREAS COVERED: In this review, we discuss the important advancements in the development of galectin-1 & 3 inhibitors. All patents filed detailing the divergent strategies to inhibit galectin-1 & 3 from 2016 to present have been covered and discussed. EXPERT OPINION: Over the past couple of decades, distinct galectin inhibitors have been synthesized, reported and studied. Among all, the mono and disaccharide-based antagonists have been found to be considerably successful. However, the cumbersome synthetic route followed to develop this class of inhibitors, in addition to complexity involved in making selective modifications within these molecules has posed a significant challenge. Recently, there have been numerous reports on heterocyclic-based galectin inhibitors. If these are established as potent galectin inhibitors, their ease of synthesis and tunability could overcome the potential drawbacks of carbohydrate-based inhibitors and could thus be exploited to develop efficient and highly specific galectin inhibitors.

Computational methods directed towards drug repurposing for COVID-19: advantages and limitations.

Novel coronavirus disease 2019 (COVID-19) has significantly altered the socio-economic status of countries. Although vaccines are now available against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a causative agent for COVID-19, it continues to transmit and newer variants of concern have been consistently emerging world-wide. Computational strategies involving drug repurposing offer a viable opportunity to choose a medication from a rundown of affirmed drugs against distinct diseases including COVID-19. While pandemics impede the healthcare systems, drug repurposing or repositioning represents a hopeful approach in which existing drugs can be remodeled and employed to treat newer diseases. In this review, we summarize the diverse computational approaches attempted for developing drugs through drug repurposing or repositioning against COVID-19 and discuss their advantages and limitations. To this end, we have outlined studies that utilized computational techniques such as molecular docking, molecular dynamic simulation, disease-disease association, drug-drug interaction, integrated biological network, artificial intelligence, machine learning and network medicine to accelerate creation of smart and safe drugs against COVID-19.

Ultrasonication-Assisted Synthesis of a d-Glucosamine-Based ß-CD Inclusion Complex and Its Application as an Aqueous Heterogeneous Organocatalytic System.

For the first time, an inclusion complex has been crafted between a carbohydrate-based molecule and a ß-cyclodextrin (CD) hydrophobic cavity for asymmetric catalytic applications. This novel d-glucosamine-based inclusion compound has been synthesized in high yields using an innovative and proficient acoustic cavitation technology and well characterized using various techniques, such as infrared spectroscopy, nuclear magnetic resonance spectroscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis, scanning electron microscopy, and other spectroscopic techniques. It was observed that the inclusion of a d-glucosamine derivative into the hydrophobic cavity of ß-CD increased its surface area and thermal stability. This catalytic system worked well in water for the direct aldol reaction to afford the products in excellent yields with high diastereo- and enantioselectivities.

Synthesis and Biological Evaluation of Imidazo[2 ,1-b]Thiazole based Sulfonyl Piperazines as Novel Carbonic Anhydrase II Inhibitors.

A novel series of imidazo[2,1-b]thiazole-sulfonyl piperazine conjugates (9aa-ee) has been synthesized and evaluated for carbonic anhydrase (CA, EC 4.2.1.1) inhibitory potency against four isoforms: The cytosolic isozyme hCA I, II and trans-membrane tumor-associated isoform hCA IX and hCA XII, taking acetazolamide (AAZ) as standard drug, using a stopped flow CO2 hydrase assay. The results revealed that most of the compounds showed selective activity against hCA II whereas none of them were active against hCA I, IX, XII (Ki > 100 µM). The physiologically dominant cytosolic isoform hCA II was inhibited by these molecules with inhibition constants in the range of 57.7-98.2 µM. This new derivative, thus, selectively inhibits hCA II over the hCA I, IX, XII isoforms, which may be used for further understanding the physiological roles of some of these isoforms in various pathologies.

Understanding the role of galectin inhibitors as potential candidates for SARS-CoV-2 spike protein: in silico studies.

The Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) has been rapidly transmitting and leaving its footprints across the globe. Stringent measures like complete lockdown and extensive testing have been employed by many countries to slow it down in its tracks until a viable treatment is found. Therefore, in the current scenario, prompt solutions need to be uncovered to tackle the virus. In the present study, 330 galectin inhibitors were tested against SARS-CoV-2 spike (S) protein with the aid of molecular docking and molecular dynamics. Finally, the binding free energy and contributing energies were calculated for 2 top scoring ligands by using MM-GBSA method. Many of the galectin inhibitors displayed high binding score against the S protein. They were found to bind to the site of contact of S protein to ACE2. Thus, they show promise of disrupting the ACE2-S protein binding and prevent the virus from invading the host cell. Among the ligands screened, TD-139, a molecule currently in Phase IIb clinical trials, was found to be a potential hit. The present study paves the way for in vitro and in vivo testing of galectin inhibitors against SARS-CoV-2. In addition, it warrants a swift examination of TD-139 for treating COVID-19.