Cytotoxicity of phosphoramidate, bis-amidate and cycloSal prodrug metabolites against tumour and normal cells.

Phosphonate and phosphate prodrugs are integral to enhancing drug permeability, but the potential toxicity of their metabolites requires careful consideration. This study evaluates the impact of widely used phosphoramidate, bis-amidate, and cycloSal phosph(on)ate prodrug metabolites on BxPC3 pancreatic cancer cells, GL261-Luc glioblastoma cells, and primary cultured mouse astrocytes. 1-Naphthol and 2-naphthol demonstrated the greatest toxicity. Notably, 2-naphthol exhibited an ED50 of 21 µM on BxPC3 cells, surpassing 1-naphthol with an ED50 of 82 µM. Real-time xCELLigence experiments revealed notable activity for both metabolites at a low concentration of 16 µM. On primary cultured mouse astrocyte cells, all prodrugs exhibited reduced viability at 128 to 256 µM after only 4 hours of exposure. A cell-type-dependent sensitivity to phosph(on)ate prodrug metabolites was evident, with normal cells showing greater susceptibility than corresponding tumour cells. The results suggest it is essential to consider the potential cytotoxicity of phosph(on)ate prodrugs in the drug design and evaluation process.

Synthesis of α-Hydroxy-1,2,3-Triazole-linked Sialyltransferase Inhibitors and Evaluation of Selectivity Towards ST3GAL1, ST6GAL1 and ST8SIA2.

Tumour-derived sialoglycans, bearing the charged nonulosonic sugar sialic acid at their termini, play a critical role in tumour cell adhesion and invasion, as well as evading cell death and immune surveillance. Sialyltransferases (ST), the enzymes responsible for the biosynthesis of sialylated glycans, are highly upregulated in cancer, with tumour hypersialylation strongly correlated with tumour growth, metastasis and drug resistance. As a result, desialylation of the tumour cell surface using either targeted delivery of a pan-ST inhibitor (or sialidase) or systemic delivery of a non-toxic selective ST inhibitors are being pursued as potential new anti-metastatic strategies against multiple cancers including pancreatic, ovarian, breast, melanoma and lung cancer. Herein, we have employed molecular modelling to give insights into the selectivity observed in a series of selective ST inhibitors that incorporate a uridyl ring in place of the cytidine of the natural donor (CMP-Neu5Ac) and replace the charged phosphodiester linker of classical ST inhibitors with a neutral α-hydroxy-1,2,3-triazole linker. The inhibitory activities of the nascent compounds were determined against recombinant human ST enzymes (ST3GAL1, ST6GAL1, ST8SIA2) showing promising activity and selectivity towards specific ST sub-types. Our ST inhibitors are non-toxic and show improved synthetic accessibility and drug-likeness compared to earlier nucleoside-based ST inhibitors.

A highly sensitive 3base™ assay for detecting Streptococcus pyogenes in saliva during controlled human pharyngitis.

Streptococcus pyogenes (Group A Streptococcus; GAS) is a Gram-positive bacterium responsible for substantial human mortality and morbidity. Conventional diagnosis of GAS pharyngitis relies on throat swab culture, a low-throughput, slow, and relatively invasive 'gold standard'. While molecular approaches are becoming increasingly utilized, the potential of saliva as a diagnostic fluid for GAS infection remains largely unexplored. Here, we present a novel, high-throughput, sensitive, and robust speB qPCR assay that reliably detects GAS in saliva using innovative 3base™ technology (Genetic Signatures Limited, Sydney, Australia). The assay has been validated on baseline, acute, and convalescent saliva samples generated from the Controlled Human Infection for Vaccination Against Streptococcus (CHIVAS-M75) trial, in which healthy adult participants were challenged with emm75 GAS. In these well-defined samples, our high-throughput assay outperforms throat culture and conventional qPCR in saliva respectively, affirming the utility of the 3base™ platform, demonstrating the feasibility of saliva as a diagnostic biofluid, and paving the way for the development of novel non-invasive approaches for the detection of GAS and other oropharyngeal pathogens.

Botanical description, phytochemical constituents, ethnobotany, traditional medicinal use, and pharmacological activities of Stachys lavandulifolia Vahl.

Stachys lavandulifolia Vahl known as "mountain tea", is a perennial flowering plant belonging to the Lamiaceae family and is widespread in Iran, Armenia, Azerbaijan, Iraq, Turkey and Turkmenistan. S. lavandulifolia is widely used in traditional medicine for its analgesic, anti-inflammatory and anxiolytic properties. This plant has different chemical compounds classes including terpenoids, iridoids, flavonoids and phenylethanoids that have been isolated from the aerial parts of it. This review covers the plant botany, traditional medicinal uses and chemical composition of S. lavandulifolia, along with its biological and pharmacological activities including clinical trial data. The information of this review article was obtained from different scientific databases such as Google scholar, Science Direct, Hindawi, SID, Scopus, PubMed, and ACS as well as traditional Persian books. Pharmacological and clinical studies, especially Anxiolytic activity and anti-inflammatory on the plant are relatively low, so these studies are suggested in the future. Also, phytochemical investigation on root of the plant is necessary.

The exploitation of human glycans by Group A Streptococcus.

Host carbohydrates, or glycans, have been implicated in the pathogenesis of many bacterial infections. Group A Streptococcus (GAS) is a Gram-positive bacterium that readily colonises the skin and oropharynx, and is a significant cause of mortality in humans. While the glycointeractions orchestrated by many other pathogens are increasingly well-described, the understanding of the role of human glycans in GAS disease remains incomplete. Although basic investigation into the mechanisms of GAS disease is ongoing, several glycointeractions have been identified and are examined herein. The majority of research in this context has focussed on bacterial adherence, however, glycointeractions have also been implicated in carbohydrate metabolism; evasion of host immunity; biofilm adaptations; and toxin-mediated haemolysis. The involvement of human glycans in these diverse avenues of pathogenesis highlights the clinical value of understanding glycointeractions in combatting GAS disease.

Molecular networking based dereplication of AChE inhibitory compounds from the medicinal plant Vincetoxicum funebre (Boiss. & Kotschy).

Alzheimer's disease (AD) is a devastating neurodegenerative disease affecting 47 million people worldwide. While acetylcholinesterase (AChE) inhibitors such as donepezil and galantamine are leading drugs in the symptomatic treatment of AD, new AChE inhibitors continue to be explored for improved potency and selectivity. Herein, a molecular networking approach using high resolution (HR-MS) and tandem mass spectrometry (MS2) has been used for rapid chemical profiling of an extract of the medicinal plant Vincetoxicum funebre Boiss. & Kotschy (Apocynaceae family) that was active against AChE. A total of 44 compounds were identified by combining the MN with traditional natural product methods, including the isolation and identification of five known compounds (13, 41-44) and a novel C13-norisoprenoid (40). In addition, the potential inhibitory activity of all 44 compounds was evaluated against the AChE enzyme via molecular docking to provide further support to the proposed structures. The glycosylated flavonoid querciturone (31) exhibited the highest affinity with a docking score value of -13.43 kJ/mol. Another five compounds showed stronger docking scores against AChE than the clinically used donepezil including the most active isolated compound daucosterol (44), with a binding affinity of -10.11 kJ/mol towards AChE. These findings broaden our understanding of Vincetoxicum metabolites and highlight the potential of glycosylated flavonoids as AChE inhibitors.Communicated by Ramaswamy H. Sarma.

Synthesis and biological evaluation of selective phosphonate-bearing 1,2,3-triazole-linked sialyltransferase inhibitors.

The critical role of sialyltransferase (ST) enzymes in tumour cell growth and metastasis, as well as links to multi-drug and radiation resistance, has seen STs emerge as a target for potential antimetastatic cancer treatments. One promising class of ST inhibitors that improve upon the pharmacokinetic issues of previous inhibitors is the 1,2,3-triazole-linked transition-state analogues. Herein, we present the design and synthesis of a new generation of 1,2,3-triazole-linked sialyltransferase inhibitors, along with their biological evaluation demonstrating increased potency for phosphonate bearing compounds. The six most promising inhibitors presented in this work exhibited a greater number of binding modes for hST6Gal I over hST3Gal I, with K i ranging from 3-55 µM. This work highlights phosphonate bearing triazole-linked compounds as a promising class of synthetically accessible ST inhibitors that warrant further investigation.

The Role of Sialylation in Respiratory Viral Infection and Treatment.

Respiratory infections caused by viruses such as influenza and coronavirus are a serious global problem due to their high infection rates and potential to spark pandemics, such as the current COVID-19 pandemic. Although preventing these infections by using vaccines has been the most successful strategy to date, effective vaccines are not always available. Therefore, developing broad-spectrum anti-viral drugs to treat such infections is essential, especially in the case of immunocompromised patients or for outbreaks of novel virus strains. Sialic acids have been highlighted as a key molecule in the viral infection cycle, with terminally sialylated glycans acting as a target for several viral proteins involved in infection, particularly respiratory infection. Inhibitors of one such protein, neuraminidase, are the only anti-influenza drugs currently on the market. Problems with neuraminidase inhibitors, including the development of resistance and a relatively narrow spectrum of activity, drive the need for an improved understanding of the viral infection cycle and the development of more resilient, broader-spectrum anti-viral treatments. Hence, this review outlines the various roles played by sialic acids in respiratory viral infection and provides examples of drugs that exploit sialic acids to inhibit viral infections. It has been concluded that drugs targeting host cell expression of sialic acid could be especially well suited to inhibiting a broad spectrum of respiratory infections. This warrants the continued design and improvement of such drugs in an attempt to lessen the burden of respiratory infections.

In vitro characterisation of 3D printed platelet lysate-based bioink for potential application in skin tissue engineering.

Wounds impact millions of patients every year and represent a serious cause of morbidity and mortality worldwide, yet current treatment outcomes are far from ideal. Therapies based on delivery of multiple growth factors offer a promising approach for optimal wound management; however, their high production cost, low stability, and lack of effective delivery system limits their application in the clinic. Platelet lysate is a suitable, abundant and cost-effective source of growth factors that play an important role in the healing cascade. The aim of this current work is to develop an extrusion-based bioink consisting of platelet lysate (PL) and gelatin methacryloyl (GelMA) (PLGMA) for the fabrication of a multifunctional 3D printed dermal equivalent. This bioink meets the essential requirements of printability in terms of rheological properties and shape fidelity. Moreover, its mechanical properties can be readily tuned to achieve stiffness that is equivalent to native skin tissue. Biologically relevant factors were successfully released in a sustainable manner for up to two weeks of study. The bioavailability of those factors was demonstrated by high cell viability, good cell attachment and improved proliferation of printed dermal fibroblasts. Furthermore, growth factors upregulated ECM synthesis and deposition by dermal fibroblasts after two weeks of culture.

Insights into the role of sialylation in cancer progression and metastasis.

Upregulation of sialyltransferases-the enzymes responsible for the addition of sialic acid to growing glycoconjugate chains-and the resultant hypersialylation of up to 40-60% of tumour cell surfaces are established hallmarks of several cancers, including lung, breast, ovarian, pancreatic and prostate cancer. Hypersialylation promotes tumour metastasis by several routes, including enhancing immune evasion and tumour cell survival, and stimulating tumour invasion and migration. The critical role of enzymes that regulate sialic acid in tumour cell growth and metastasis points towards targeting sialylation as a potential new anti-metastatic cancer treatment strategy. Herein, we explore insights into the mechanisms by which hypersialylation plays a role in promoting metastasis, and explore the current state of sialyltransferase inhibitor development.

Characterization and Antibacterial Activity of Phthalides from the Roots of the Medicinal Herb Levisticum officinale W.D.J. Koch.

A new phthalide, namely 7-methoxy-3-propylidenephthalide (1), along with two known compounds (2, 3) were isolated from the roots of the edible herb Levisticum officinale W.D.J. Koch, commonly known as lovage and well known in traditional medicine for its spasmolytic and diuretic effects. The structure of the new compound was established by HRMS and 1D & 2D NMR (1H 1H COSY, HMQC, and HMBC) spectroscopic analysis. All compounds are reported for the first time from L. officinale. Compounds 1-3 were tested against two Gram negative (Escherichia coli, Pseudomonas aeruginosa) and two Gram positive (Staphylococcus aureus and vancomycin-resistant Enterococcus [VRE] faecium) bacteria strains. Compound 3 was active against S. aureus, E. coli and vancomycin-resistant E. faecium with MIC values of 16, 64, and 128 µg/mL, respectively.

Design, synthesis and evaluation of carbamate-linked uridyl-based inhibitors of human ST6Gal I.

Sialic acid at the terminus of cell surface glycoconjugates is a critical element in cell-cell recognition, receptor binding and immune responses. Sialyltransferases (ST), the enzymes responsible for the biosynthesis of sialylated glycans are highly upregulated in cancer and the resulting hypersialylation of the tumour cell surface correlates strongly with tumour growth, metastasis and drug resistance. Inhibitors of human STs, in particular human ST6Gal I, are thus expected to be valuable chemical tools for the discovery of novel anticancer drugs. Herein, we report on the computationally-guided design and development of uridine-based inhibitors that replace the charged phosphodiester linker of known ST inhibitors with a neutral carbamate to improve pharmacokinetic properties and synthetic accessibility. A series of 24 carbamate-linked uridyl-based compounds were synthesised by coupling aryl and hetaryl α-hydroxyphosphonates with a 5'-amino-5'-deoxyuridine fragment. The inhibitory activities of the newly synthesised compounds against recombinant human ST6Gal I were determined using a luminescent microplate assay, and five promising inhibitors with Ki's ranging from 1 to 20 µM were identified. These results show that carbamate-linked uridyl-based compounds are a potential new class of readily accessible, non-cytotoxic ST inhibitors to be further explored.

Acetylcholinesterase-inhibitory activity of Iranian plants: Combined HPLC/bioassay-guided fractionation, molecular networking and docking strategies for the dereplication of active compounds.

In order to search for discovery of acetylcholinesterase (AChE) inhibitors, as a therapeutic strategy for treatment of the Alzheimer's disease, twenty-five Iranian plants have been evaluated by an in vitro enzymatic Ellman method and molecular docking study. Each plant was successively extracted by n-hexane, ethyl acetate and methanol to obtain a total of 75 extracts. The inhibiting effect of extracts was measured by a colorimetric assay in 96-well microplates. The n-hexane extract of Prangos ferulacea showed the highest AChE inhibitory activity with 75.6% inhibition at a concentration of 50 µg/mL. The chemical composition of this extract was investigated in detail based on a combination of HPLC/bioassay-guided fractionation and molecular networking techniques. The results led to the identification of seventeen compounds, one of them was a fatty acid derivative, two compounds had flavonoid structure and others were furanocoumarin type compounds. In vitro analysis showed that the subfraction F10f was the most potent inhibitor against the activity of AChE with an IC50 value of 25.2 µg/mL and good docking scores of its constituents confirming its high activity.

Eyes in the sea: Unlocking the mysteries of the ocean using industrial, remotely operated vehicles (ROVs).

For thousands of years humankind has sought to explore our oceans. Evidence of this early intrigue dates back to 130,000BCE, but the advent of remotely operated vehicles (ROVs) in the 1950s introduced technology that has had significant impact on ocean exploration. Today, ROVs play a critical role in both military (e.g. retrieving torpedoes and mines) and salvage operations (e.g. locating historic shipwrecks such as the RMS Titanic), and are crucial for oil and gas (O&G) exploration and operations. Industrial ROVs collect millions of observations of our oceans each year, fueling scientific discoveries. Herein, we assembled a group of international ROV experts from both academia and industry to reflect on these discoveries and, more importantly, to identify key questions relating to our oceans that can be supported using industry ROVs. From a long list, we narrowed down to the 10 most important questions in ocean science that we feel can be supported (whole or in part) by increasing access to industry ROVs, and collaborations with the companies that use them. The questions covered opportunity (e.g. what is the resource value of the oceans?) to the impacts of global change (e.g. which marine ecosystems are most sensitive to anthropogenic impact?). Looking ahead, we provide recommendations for how data collected by ROVs can be maximised by higher levels of collaboration between academia and industry, resulting in win-win outcomes. What is clear from this work is that the potential of industrial ROV technology in unravelling the mysteries of our oceans is only just beginning to be realised. This is particularly important as the oceans are subject to increasing impacts from global change and industrial exploitation. The coming decades will represent an important time for scientists to partner with industry that use ROVs in order to make the most of these 'eyes in the sea'.

Computer-aided design of human sialyltransferase inhibitors of hST8Sia III.

Sialyltransferase (ST) upregulation and the resultant hypersialylation of tumour cell surfaces is an established hallmark of many cancers including lung, breast, ovarian, pancreatic and prostate cancer. The role of ST enzymes in tumour cell growth and metastasis, as well as links to multi-drug resistance, has seen ST inhibition emerge as a target for potential antimetastatic cancer treatments. The most potent of these reported inhibitors are transition-state analogues. Although there are several examples of these in the literature, many have suspected poor pharmacokinetic properties and are not readily synthetically accessible. A proposed solution to these problems is the use of a neutral carbamate or 1,2,3-triazole linker instead of the more commonly used phosphodiester linker, and replacing the traditionally utilised cytidine nucleotide with uridine. Another issue in this area is the paucity of structural information of human ST enzymes. However, in late 2015 the structure of human ST8Sia III was reported (only the second human ST described so far), creating the opportunity for structure-based design of selective ST8 inhibitors for the first time. Herein, molecular docking and molecular dynamics simulations with the newly published crystal structure of hST8Sia III were performed for the first time with selected ST transition state analogues. Simulations showed that these compounds could participate in many of the key interactions common with the natural donor and acceptor substrates, and reveals some key insights into the synthesis of potentially selective ST inhibitors.

Transition state-based ST6Gal I inhibitors: Mimicking the phosphodiester linkage with a triazole or carbamate through an enthalpy-entropy compensation.

Human ß-galactoside α-2,6-sialyltransferase I (ST6Gal I) catalyses the synthesis of sialylated glycoconjugates. Overexpression of ST6Gal I is observed in many cancers, where it promotes metastasis through altered cell surface sialylation. A wide range of sialyltransferase inhibitors have been developed, with analogues structurally similar to the transition state exhibiting the highest inhibitory activity. To improve synthetic accessibility and pharmacokinetics of previously reported inhibitors, the replacement of the charged phosphodiester linker with a potential neutral isostere such as a carbamate or a 1,2,3-triazole has been investigated. Extensive molecular dynamics simulations have demonstrated that compounds with the alternate linkers could maintain key interactions with the human ST6Gal I active site, demonstrating the potential of a carbamate or a 1,2,3-triazole as a phosphodiester isostere. Free energy perturbation calculations provided energetic evidence suggesting that the carbamate and 1,2,3-triazole were slightly more favourable than the phosphodiester. Further exploration with free energy component, quasi-harmonic and cluster analysis suggested that there is an enthalpy-entropy compensation accounting for the replacement of the flexible charged phosphodiester with a neutral and rigid isostere. Overall, these simulations provide a strong rationale for the use of a carbamate or 1,2,3-triazole as a phosphodiester isostere in the development of novel inhibitors of human ST6Gal I.

Computational Glycobiology: Mechanistic Studies of Carbohydrate-Active Enzymes and Implication for Inhibitor Design.

Carbohydrate-active enzymes (CAZymes) are families of essential and structurally related enzymes, which catalyze the creation, modification, and degradation of glycosidic bonds in carbohydrates to maintain essentially all kingdoms of life. CAZymes play a key role in many biological processes underpinning human health and diseases (e.g., cancer, diabetes, Alzheimer's diseases, AIDS) and have thus emerged as important drug targets in the fight against pathogenesis. The realization of the full potential of CAZymes remains a significant challenge, relying on a deeper understanding of the molecular mechanisms of catalysis. Considering numerous unsettled questions in the literature, while with a large amount of structural, kinetic, and mutagenesis data available for CAZymes, there is a pressing need and an abundant opportunity for collaborative computational and experimental investigations with the aim to unlock the secrets of CAZyme catalysis at an atomic level. In this review, we briefly survey key methodology development in computational studies of CAZyme catalysis. This is complemented by selected case studies highlighting mechanistic insights provided by computational glycobiology. Implication for inhibitor design by mimicking the transition state is also illustrated for both glycoside hydrolases and glycosyltransferases. The challenges for such studies will be noted and finally an outlook for future directions will be provided.

Advancement of Sialyltransferase Inhibitors: Therapeutic Challenges and Opportunities.

Hypersialylation of tumor cell surface proteins along with a marked upregulation of sialyltransferase (ST) activity is a well-established hallmark of cancer. Due to the critical role of STs in tumor growth and progression, ST inhibition has emerged as a potential new antimetastatic strategy for a range of cancers including pancreatic and ovarian. Human STs are divided into subtypes based on their linkage and acceptor molecule, with each subtype controlling the synthesis of specific sialylated structures with unique biological roles. This has important implications for inhibitor development, as STs also play significant roles in immune responses, inflammation, viral infection, and neurological disorders. Thus, the current goal in order to advance to the clinic is the development of subtype selective, cell-permeable and synthetically accessible, small-molecule ST inhibitors. Herein is a comprehensive review of the latest developments in ST inhibitors from design, Nature, and high-throughput screening, addressing both the challenges and opportunities in targeting cell surface sialylation. The review features an overview of the biological evaluation methods, computational and imaging tools, inhibitor molecular diversity, and selectivity toward ST subtypes, along with the emerging role of ST inhibitors as diagnostic tools for disease imaging.

Parameters affecting the analytical profile of fatty acids in the macroalgal genus Ulva.

The fatty acids (FA) of Ulva have potential to contribute to nutrition. However the large variability of FA profiles of Ulva species; thus the quality and quantity of FA in relation to nutrition is poorly defined. Herein we investigate the FA profile of 74 cultured Ulva samples crossing five culture regimes, six extraction regimes and four post-harvesting processes. This is compared alongside a comprehensive review of FA profiles of Ulva spp. With regard to the literature, Ulva is characterised by C16:0 (30.5±11.5%), C18:3 n-3 (14.5±6.3%), C18:4 n-3 (12.5±5.4%), C16:4 n-3 (8.9±4.8%) and C18:1 n-7 (10.1±4.0%). The investigated Ulva fell within the reported range of specific FA. High nutrient conditions showed the most desirable FA profile for health, along with the highest total FA content (56mgg(-1) dry weight equivalent) when extracted with an optimised protocol.

Computational characterisation of the interactions between human ST6Gal I and transition-state analogue inhibitors: insights for inhibitor design.

Human ß-galactoside α-2,6-sialyltransferase I (hST6Gal I) catalyses the synthesis of sialylated glycoconjugates involved in cell-cell interactions. Overexpression of hST6Gal I is observed in many different types of cancers, where it promotes metastasis through altered cell surface sialylation. A wide range of sialyltransferase (ST) inhibitors have been developed based on the natural donor, cytidine 5'-monophosphate N-acetylneuraminic acid (CMP-Neu5Ac). Of these, analogues that are structurally similar to the transition state exhibit the highest inhibitory activity. In order to design inhibitors that are readily accessible synthetically and with favourable pharmacokinetic properties, an investigation of the replacement of the charged phosphodiester-linker, present in many ST inhibitors, with a potential neutral isostere such as a carbamate or a 1,2,3-triazole has been undertaken. To investigate this, molecular docking and molecular dynamics simulations were performed. These simulations provided an insight into the binding mode of previously reported phosphodiester-linked ST inhibitors and demonstrated that targeting the proposed sialyl acceptor site is a viable option for producing selective inhibitors. The potential for a carbamate- or triazole-linker as an isosteric replacement for the phosphodiester in transition-state analogue ST inhibitors was established using molecular docking. Molecular dynamics simulations of carbamate- and phosphodiester-linked compounds revealed that both classes exhibit consistent interactions with hST6Gal I. Overall, the results obtained from this study provide a rationale for synthetic and biological evaluation of triazole- and carbamate-linked transition-state analogue ST inhibitors as potential new antimetastatic agents.