HGF/c-Met pathway inhibition combined with chemotherapy increases cytotoxic T-cell infiltration and inhibits pancreatic tumour growth and metastasis.

Pancreatic cancer (PC) is a deadly cancer with a high mortality rate. The unique characteristics of PC, including desmoplasia and immunosuppression, have made it difficult to develop effective treatment strategies. Pancreatic stellate cells (PSCs) play a crucial role in the progression of the disease by interacting with cancer cells. One of the key mediators of PSC - cancer cell interactions is the hepatocyte growth factor (HGF)/c-MET pathway. Using an immunocompetent in vivo model of PC as well as in vitro experiments, this study has shown that a combined approach using HGF/c-MET inhibitors to target stromal-tumour interactions and chemotherapy (gemcitabine) to target cancer cells effectively decreases tumour volume, EMT, and stemness, and importantly, eliminates metastasis. Notably, HGF/c-MET inhibition decreases TGF-ß secretion by cancer cells, resulting in an increase in cytotoxic T-cell infiltration, thus contributing to cancer cell death in tumours. HGF/c-MET inhibition + chemotherapy was also found to normalise the gut microbiome and improve gut microbial diversity. These findings provide a strong platform for assessment of this triple therapy (HGF/c-MET inhibition + chemotherapy) approach in the clinical setting.

Repurposing of existing antibiotics for the treatment of diabetes mellitus.

Proline specific serine protease enzyme, dipeptidyl peptidase IV (DPP-4) has become a promising target for diabetes, as it stops glucagon-like peptide 1 (GLP-1) from becoming inactive, resulting in higher levels of active GLP-1. This lowers glucose levels by increasing insulin secretion and decreasing glucagon secretion. DPP-4 is also linked to a higher BMI and a 0.7 to 1% reduction in HbA1c. Currently available DPP-4 inhibitor drugs showed less promising anti-diabetic activity as this class associated with many side effects due to non-selectivity and therefore searching on more potent DPP-4 inhibitors are still ongoing. In our present study, we investigate the inhibition of DPP-4 through a series of antibiotic compounds which were previously reported to be used in diabetic foot infections and compared with existing DPP-4 inhibitors. To obtain this objective, three-dimensional crystal structure of DPP-4 was retrieved from the protein data bank (PDB id: 1 × 70). A systematic computational method combining molecular docking, MM-GBSA binding energy calculation, MD simulations, MM-PBSA binding free energy calculations and ADME were used to find best DPP-4 inhibitor. Molecular docking results revealed that clindamycin has a higher affinity towards the catalytic sides of DPP-4 and built solid hydrophobic and polar interactions with the amino acids involved in the binding region of DPP-4, such as S1 subsite, S2 subsite and S2 extensive subsite. MD simulations results showed clindamycin as potent virtual hit and suggested that it binds with DPP-4 in competitive manner, which virtually indicate that besides antibiotic activity clindamycin has anti-diabetic activity. Supplementary Information: The online version contains supplementary material available at 10.1007/s40203-021-00118-6.

Ziziphus oenoplia Mill.: A Systematic Review on Ethnopharmacology, Phytochemistry and Pharmacology of an Important Traditional Medicinal Plant.

BACKGROUND: Ziziphus oenoplia Mill. (Family- Rhamnaceae) an important shrub, often found throughout the hot regions of tropical Asia and northern Australia, is commonly well known as Jackal jujube in English. It is a folk herbal medicine used as an abdominal pain killer and antidiarrhoeal agent. OBJECTIVE: The review aims to provide up-to-date information on the vernacular information, botanical characterization, distribution, ethnopharmacological uses, pharmacological activities, and chemical constituents of Z. oenoplia for possible exploitation of treatment for various diseases and to suggest future investigations. METHODS: This review was performed by studying online resources relating to Z. oenoplia and diverse resources, including scientific journals, books, and worldwide accepted databases from which information was assembled to accumulate significant information and relevant data in one place. RESULTS: Investigations on Z. oenoplia have been focused on its pharmacological activities, including its antimicrobial, antidiabetic, antihepatotoxic, antiulcer, antiplasmodial, anticancer, wound healing, anthelmintic, antioxidant, analgesic and antinociceptive, hypolipidemic activity, anti-inflammatory, immunomodulatory and antidiarrheal activities. Phytochemical studies resulted in the isolation of fatty acids, flavonoids, phenols, pentacyclic triterpenes, hydroxycarboxylic acids, aliphatic hydroxy ether, and cyclopeptide alkaloids. CONCLUSION: Most of the ethnopharmacological relevance of Z. oenoplia is justified, but more studies are needed. Further investigations are necessary to fully understand the mode of action of the active constituents and to exploit its preventive and therapeutic potentials.

GreenMolBD: Nature Derived Bioactive Molecules' Database.

BACKGROUND: One of the essential resources for developing new drugs are naturally derived biologically active lead compounds. Biomedical researchers and pharmaceutical companies are highly interested in these plant-derived molecules to develop the new drug. In this process, collective information of the plants and their phytoconstituents with different properties and descriptors would greatly benefit the researchers to identify the hit, lead or drug-like compound. AIM AND OBJECTIVE: Therefore, the work intended to develop a unique and dynamic database Green- MolBD to provide collective information regarding medicinal plants, such as their profile, chemical constituents, and pharmacological evidence. We also aimed to present information of phytoconstituents, such as in silico description, quantum, drugability and biological target information. METHODS: For data mining, we covered all accessible literature and books, and for in silico analysis, we employed a variety of well-known software and servers. The database is integrated by MySQL, HTML, PHP and JavaScript. RESULTS: GreenMolBD is a freely accessible database and searchable by keywords, plant name, synonym, common name, family name, family synonym, compound name, IUPAC name, InChI Key, target name, and disease name. We have provided a complete profile of individual plants and each compound's physical, quantum, drug likeliness, and toxicity properties (48 type's descriptor) using in silico tools. A total of 1846 associated targets related to 6,864 compounds already explored in different studies are also incorporated and synchronized. CONCLUSION: This is the first evidence-based database of bioactive molecules from medicinal plants specially grown in Bangladesh, which may help explore and foster nature-inspired rational drug discovery.

Whole proteome screening and identification of potential epitopes of SARS-CoV-2 for vaccine design-an immunoinformatic, molecular docking and molecular dynamics simulation accelerated robust strategy.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the most cryptic pandemic outbreak of the 21st century, has gripped more than 1.8 million people to death and infected almost eighty six million. As it is a new variant of SARS, there is no approved drug or vaccine available against this virus. This study aims to predict some promising cytotoxic T lymphocyte epitopes in the SARS-CoV-2 proteome utilizing immunoinformatic approaches. Firstly, we identified 21 epitopes from 7 different proteins of SARS-CoV-2 inducing immune response and checked for allergenicity and conservancy. Based on these factors, we selected the top three epitopes, namely KAYNVTQAF, ATSRTLSYY, and LTALRLCAY showing functional interactions with the maximum number of MHC alleles and no allergenicity. Secondly, the 3D model of selected epitopes and HLA-A*29:02 were built and Molecular Docking simulation was performed. Most interestingly, the best two epitopes predicted by docking are part of two different structural proteins of SARS-CoV-2, namely Membrane Glycoprotein (ATSRTLSYY) and Nucleocapsid Phosphoprotein (KAYNVTQAF), which are generally target of choice for vaccine designing. Upon Molecular Docking, interactions between selected epitopes and HLA-A*29:02 were further validated by 50 ns Molecular Dynamics (MD) simulation. Analysis of RMSD, Rg, SASA, number of hydrogen bonds, RMSF, MM-PBSA, PCA, and DCCM from MD suggested that ATSRTLSYY is the most stable and promising epitope than KAYNVTQAF epitope. Moreover, we also identified B-cell epitopes for each of the antigenic proteins of SARS CoV-2. Findings of our work will be a good resource for wet lab experiments and will lessen the timeline for vaccine construction.Communicated by Ramaswamy H. Sarma.

Metastatic phenotype and immunosuppressive tumour microenvironment in pancreatic ductal adenocarcinoma: Key role of the urokinase plasminogen activator (PLAU).

Background: Previous studies have revealed the role of dysregulated urokinase plasminogen activator (encoded by PLAU) expression and activity in several pathways associated with cancer progression. However, systematic investigation into the association of PLAU expression with factors that modulate PDAC (pancreatic ductal adenocarcinoma) progression is lacking, such as those affecting stromal (pancreatic stellate cell, PSC)-cancer cell interactions, tumour immunity, PDAC subtypes and clinical outcomes from potential PLAU inhibition. Methods: This study used an integrated bioinformatics approach to identify prognostic markers correlated with PLAU expression using different transcriptomics, proteomics, and clinical data sets. We then determined the association of dysregulated PLAU and correlated signatures with oncogenic pathways, metastatic phenotypes, stroma, immunosuppressive tumour microenvironment (TME) and clinical outcome. Finally, using an in vivo orthotopic model of pancreatic cancer, we confirmed the predicted effect of inhibiting PLAU on tumour growth and metastasis. Results: Our analyses revealed that PLAU upregulation is not only associated with numerous other prognostic markers but also associated with the activation of various oncogenic signalling pathways, aggressive phenotypes relevant to PDAC growth and metastasis, such as proliferation, epithelial-mesenchymal transition (EMT), stemness, hypoxia, extracellular cell matrix (ECM) degradation, upregulation of stromal signatures, and immune suppression in the tumour microenvironment (TME). Moreover, the upregulation of PLAU was directly connected with signalling pathways known to mediate PSC-cancer cell interactions. Furthermore, PLAU upregulation was associated with the aggressive basal/squamous phenotype of PDAC and significantly reduced overall survival, indicating that this subset of patients may benefit from therapeutic interventions to inhibit PLAU activity. Our studies with a clinically relevant orthotopic pancreatic model showed that even short-term PLAU inhibition is sufficient to significantly halt tumour growth and, importantly, eliminate visible metastasis. Conclusion: Elevated PLAU correlates with increased aggressive phenotypes, stromal score, and immune suppression in PDAC. PLAU upregulation is also closely associated with the basal subtype type of PDAC; patients with this subtype are at high risk of mortality from the disease and may benefit from therapeutic targeting of PLAU.

Mollusc-Derived Brominated Indoles for the Selective Inhibition of Cyclooxygenase: A Computational Expedition.

Inflammation plays an important role in different chronic diseases. Brominated indoles derived from the Australian marine mollusk Dicathais orbita (D. orbita) are of interest for their anti-inflammatory properties. This study evaluates the binding mechanism and potentiality of several brominated indoles (tyrindoxyl sulfate, tyrindoleninone, 6-bromoisatin, and 6,6'-dibromoindirubin) against inflammatory mediators cyclooxygenases-1/2 (COX-1/2) using molecular docking, followed by molecular dynamics simulation, along with physicochemical, drug-likeness, pharmacokinetic (pk), and toxicokinetic (tk) properties. Molecular docking identified that these indole compounds are anchored, with the main amino acid residues, positioned in the binding pocket of the COX-1/2, required for selective inhibition. Moreover, the molecular dynamics simulation based on root mean square deviation (RMSD), radius of gyration (Rg), solvent accessible surface area (SASA), and root mean square fluctuation (RMSF) analyses showed that these natural brominated molecules transit rapidly to a progressive constant configuration during binding with COX-1/2 and seem to accomplish a consistent dynamic behavior by maintaining conformational stability and compactness. The results were comparable to the Food and Drug Administration (FDA)-approved selective COX inhibitor, aspirin. Furthermore, the free energy of binding for the compounds assessed by molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) confirmed the binding capacity of indoles towards COX-1/2, with suitable binding energy values except for the polar precursor tyrindoxyl sulfate (with COX-1). The physicochemical and drug-likeness analysis showed zero violations of Lipinski's rule, and the compounds are predicted to have excellent pharmacokinetic profiles. These indoles are projected to be non-mutagenic and free from hepatotoxicity, with no inhibition of human ether-a-go-go gene (hERG) I inhibitors, and the oral acute toxicity LD50 in rats is predicted to be similar or lower than aspirin. Overall, this work has identified a plausible mechanism for selective COX inhibition by natural marine indoles as potential therapeutic candidates for the mitigation of inflammation.

A Comprehensive Review on Linum usitatissimum Medicinal Plant: Its Phytochemistry, Pharmacology, and Ethnomedicinal Uses.

BACKGROUND: Linum usitatissimum or flax has been broadly utilized in numerous milieus worldwide as a primeval medicinal plant because of its health benefits in diverse types of diseases. OBJECTIVE: The objective of this review is to assemble the latest information on the botanical description, distribution, conventional uses, and biochemical constituents, along with the pharmacological activities and toxicity of flax. METHODS: For this purpose, data on Linum was accumulated from scientific journals, books, and worldwide acknowledged scientific databases via a library and electronic search. RESULTS: Phytochemical analysis showed that the major chemical constituents of L. usitatissimum are ω-3 fatty acid, phytoestrogenic-lignans (secoisolariciresinol diglucoside-SDG), phenols, flavonoids, sterols, proteins, antioxidants as well as various soluble and insoluble fibres. Among them, secoisolariciresinol diglucosides (SDG) are the major bioactive compounds of L. usitatissimum with prospective pharmacological accomplishments. Pure compounds and crude extracts isolated from L. usitatissimum exhibited significant anti-cancer, antioxidant, anti-microbial, anti-inflammatory, anti-obesity, antidiabetic, anti-diarrheal, anti-malarial, hepato-protective, reno-protective, immunosuppressive, antiarrhythmic, and cognitive effects. Studies indicated that the toxicological effect from the consumption of flaxseed is because of its cyanogenic glycosides, linatine, and cadmium, but the level does not seem to be adequately concentrated to contribute to any physiological impact. CONCLUSIONS: Further studies are expected to comprehend the detailed mode of action of its dynamic constituents as potent therapeutics and to completely reveal its preventive and healing potentials.

Adhatoda vasica (Nees.): A Review on its Botany, Traditional uses, Phytochemistry, Pharmacological Activities and Toxicity.

BACKGROUND: Adhatoda vasica (Nees.) of the family Acanthaceae has been used in the Southeast tropical zone as it is efficacious against headache, colds, cough, whooping cough, fever, asthma, dyspnea, phthisis, jaundice, chronic bronchitis, and diarrhea. It exhibits commendable pharmacological activities. OBJECTIVE: The aim of the review is to provide a systematic overview of pharmacological activities with toxicity and clinical assessment, phytochemistry of A. vasica along with its characterization, geographical observation, phenology, traditional uses, as well as an organized representation of the findings. METHOD: The overall information of A. vasica was collected from various resources, including books, review papers, research papers, and reports which were obtained from an online search of globallyaccepted scientific databases. ChemDraw software was used to draw the compound's structure. RESULTS: Phytochemical review on A. vasica has led to the collection of 233 compounds of different types such as alkaloids, flavonoids, essential oils, terpenoids, fatty acids, phenols, etc. It is a promising source of potential phytopharmaceutical agent that exhibits diverse pharmacological activities, including antibacterial, antifungal, hepatoprotective, anti-ulcer, abortifacient, antiviral, antiinflammatory, thrombolytic, hypoglycemic, anti-tubercular, antioxidant, and antitussive activities. CONCLUSIONS: Sufficient number of studies on ethnopharmacology, traditional uses, and pharmacological activities of A. vasica are conducted. Furthermore, it is necessary to study the activity of chemical constituents for new drug design and discovery from natural products.

Brassica oleracea var. capitata f. alba: A Review on its Botany, Traditional uses, Phytochemistry and Pharmacological Activities.

BACKGROUND: Brassica oleracea var. capitata f. alba (white cabbage) is a cruciferous vegetable used as a vegetable and traditional medicine all over the world. Different preparation from several parts of the plant- roots, shoots, leaves, and the whole plant are used to treat a wide range of diseases, including diabetes, cancer, gastric, inflammation, hypertension, hypercholesterolemia, bacterial, oxidation, and obesity. OBJECTIVE: The aim of the current review is to evaluate the botany, distribution, traditional uses, phytochemistry, and pharmacological activities of B. oleracea var. capitata. Moreover, this review will guide to fill the existing gaps in information and highlight additional research prospects in the field of phytochemistry and pharmacology. METHOD: Various resources, including research papers, review papers, books, and reports, were collected to obtain overall information on Brassica oleracea var. capitata, which were obtained by an online search of worldwide-accepted scientific databases. Phytochemical constituents' structures were drawn by ChemDraw software. RESULTS: About 72 isolated phytochemical compounds of B. oleracea var. capitata have been collected from different articles, which included different types of compounds such as alkaloids, flavonoids, organic acids, glucosinolates, steroids, hydrocarbons, etc. Crude extracts and phytoconstituents of B. oleracea var. capitata have various pharmacological effects, including antidiabetic, anticancer, antihypertensive, anticholesterolemic, antioxidant, anti-inflammatory, antibacterial, anti-obesity, anticoagulant, and hepatoprotective. We have enlisted all these pharmacological data along with all the phytochemical constituents of Brassica oleracea var. capitata. CONCLUSION: The study was focused on the traditional uses, pharmacological activities, and phytochemistry of Brassica oleracea var. capitata, and the findings indicated that B. oleracea var. capitata is an important medicinal plant that shows several pharmacological effects. We hope our review of this plant will provide more basic and useful information and fill some research gaps for further investigation and drug design. Although we found some important traditional uses and pharmacological activities of Brassica oleracea var. capitata, there is insufficient work in the field of phytochemical activities.

Phytochemistry, Traditional Uses and Pharmacological Properties of Enhydra fluctuans Lour: a Comprehensive Review.

BACKGROUND: Enhydra fluctuans Lour, a tropical herb, commonly known as helencha or harkuch, belongs to the family Asteraceae. It is an edible semi-aquatic herbaceous vegetable plant with serrate leaves and grows commonly in different parts of the world. Enhydra fluctuans possesses potential pharmacological role against inflammation, cancer, diarrhea, microbial infection, diabetes, etc. Aim: This review aims to provide the most current information on the botanical characterization, distribution, traditional uses, chemical constituents, as well as the pharmacological activities of Enhydra fluctuans Lour. MATERIALS AND METHODS: The recently updated information on Enhydra fluctuans was gathered from scientific journals, books, and worldwide accepted scientific databases via a library and electronic search PubMed, Elsevier, Google Scholar, Springer, Scopus, Web of Science, Wiley online library. All of the full-text articles and abstracts related to Enhydra were screened. The most important and relevant articles were carefully chosen for study in this review. RESULTS: Crude extracts and isolated compounds of Enhydra fluctuans Lour have been reported to be pharmacologically active against cytoprotective, analgesic and anti-inflammatory, antimicrobial, anticancer, antidiarrheal, antihelmintic, CNS depressant, hepatoprotective, thrombolytic, antidiabetic, antioxidant, phagocytic and cytotoxic, and neuroprotective potential activities. DISCUSSION: Phytochemical analysis from different studies has reported Germacranolide, Sesquiterpene lactone, Flavonoid, Essential oil, Steroid, Diterpenoid, Melampolide, Sesquiterpene lactone, and Isoflavone glycoside as major compounds of Enhydra fluctuans Lour. CONCLUSION: However, more research is needed to explore the mode of action of bioactive components of the plant and its therapeutic capabilities.

Molecular simulation studies to reveal the binding mechanisms of shikonin derivatives inhibiting VEGFR-2 kinase.

Traditional vascular endothelial growth factor receptor 2 (VEGFR-2) inhibitors can manage angiogenesis; however, severe toxicity and resistance limit their long-term applications in clinical therapy. Shikonin (SHK) and its derivatives could be promising to inhibit the VEGFR-2 mediated angiogenesis, as they are reported to bind in the catalytic kinase domain with low affinity. However, the detailed molecular insights and binding dynamics of these natural inhibitors are unknown, which is crucial for potential SHK based lead design. Therefore, the present study employed molecular modeling and simulations techniques to get insight into the binding behaviors of SHK and its two derivates, ß-hydroxyisovalerylshikonin (ß-HIVS) and acetylshikonin (ACS). Here the intermolecular interactions between protein and ligands were studied by induced fit docking approach, which were further evaluated by treating QM/MM (quantum mechanics/molecular mechanics) and molecular dynamics (MD) simulation. The result showed that the naphthazarin ring of the SHK derivates is vital for strong binding to the catalytic domain; however, the binding stability can be modulated by the side chain modification. Because of having electrostatic potential, this ring makes essential interactions with the DFG (Asp1046 and Phe1047) motif and also allows interacting with the allosteric binding site. Taken together, the studies will advance our knowledge and scope for the development of new selective VEGFR-2 inhibitors based on SHK and its analogs.

Design of novel viral attachment inhibitors of the spike glycoprotein (S) of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) through virtual screening and dynamics.

To date, the global COVID-19 pandemic has been associated with 11.8 million cases and over 545481 deaths. In this study, we have employed virtual screening approaches and selected 415 lead-like compounds from 103 million chemical substances, based on the existing drugs, from PubChem databases as potential candidates for the S protein-mediated viral attachment inhibition. Thereafter, based on drug-likeness and Lipinski's rules, 44 lead-like compounds were docked within the active side pocket of the viral-host attachment site of the S protein. Corresponding ligand properties and absorption, distribution, metabolism, excretion, and toxicity (ADMET) profile were measured. Furthermore, four novel inhibitors were designed and assessed computationally for efficacy. Comparative analysis showed the screened compounds in this study maintain better results than the proposed mother compounds, VE607 and SSAA09E2. The four designed novel lead compounds possessed more fascinating output without deviating from any of Lipinski's rules. They also showed higher bioavailability and the drug-likeness score was 0.56 and 1.81 compared with VE607 and SSAA09E2, respectively. All the screened compounds and novel compounds showed promising ADMET properties. Among them, the compound AMTM-02 was the best candidate, with a docking score of -7.5 kcal/mol. Furthermore, the binding study was verified by molecular dynamics simulation over 100 ns by assessing the stability of the complex. The proposed screened compounds and the novel compounds may give some breakthroughs for the development of a therapeutic drug to treat SARS-CoV-2 proficiently in vitro and in vivo.

A Review of Saurauia roxburghii Wall. (Actinidiacaea) as a Traditional Medicinal Plant, Its Phytochemical Study and Therapeutic Potential.

Saurauia roxburghii Wall. is an interesting plant, found growing chiefly along the eastern and south-eastern countries of Asia. The various ethnic groups of these regions use the plant as a medication for relieving a wide spectrum of diseases and conditions, including indigestion, boils, fever, gout, piles, eczema, asthma, ulcers, bronchitis, epilepsy, and hepatitis B. This review aims to appraise the vernacular information, botanical characterization, geographical distribution, traditional uses, phytochemistry, and pharmacological activities of S. roxburghii as well as to conduct a critical analysis on the findings. To understand the therapeutic potential and provide an overall idea about the ethnomedicinal practices, phytochemistry, and pharmacological activities of S. roxburghii, relevant information was collected via a library and electronic search of online journals, books, and reputed databases. Phytochemical examination revealed the presence of alkaloids, glycosides, O-glycosides, flavonoids, carbohydrates, saponins, steroids, reducing sugars, tannins, phlobatannins, and triterpenoids. The sterols were identified as Stigmasterol and beta-Sitosterol. The triterpenes were found to be Ursolic acid, Corosolic acid, Maslinic acid, 24-Hydroxy corosolic acid, 3b,7b,24-trihydroxy-urs-12-en-28-oic acid, Oleanolic acid, beta-Amyrin, cis-3-O-p-Hydroxycinnamoyl ursolic acid, trans-3-O-p- Hydroxycinnamoyl ursolic acid, and 7,24-dihydroxyursolic acid. Several in-vivo and in-vitro tests revealed anti-bacterial, anti-cancer, anti-diabetic, anti-oxidant, and anti-viral activities of the plant leaves. Detailed analysis of the information collected on S. roxburghii suggested some promising leads for future drug development. However, many scientific gaps were found in the study of this and further extensive investigation is needed to fully understand the mechanism of action of the active constituents and exploit its therapeutic promises.

Structural and Dynamic Characterizations Highlight the Deleterious Role of SULT1A1 R213H Polymorphism in Substrate Binding.

Sulfotransferase 1A1 (SULT1A1) is responsible for catalyzing various types of endogenous and exogenous compounds. Accumulating data indicates that the polymorphism rs9282861 (R213H) is responsible for inefficient enzymatic activity and associated with cancer progression. To characterize the detailed functional consequences of this mutation behind the loss-of-function of SULT1A1, the present study deployed molecular dynamics simulation to get insights into changes in the conformation and binding energy. The dynamics scenario of SULT1A1 in both wild and mutated types as well as with and without ligand showed that R213H induced local conformational changes, especially in the substrate-binding loop rather than impairing overall stability of the protein structure. The higher conformational changes were observed in the loop3 (residues, 235-263), turning loop conformation to A-helix and B-bridge, which ultimately disrupted the plasticity of the active site. This alteration reduced the binding site volume and hydrophobicity to decrease the binding affinity of the enzyme to substrates, which was highlighted by the MM-PBSA binding energy analysis. These findings highlight the key insights of structural consequences caused by R213H mutation, which would enrich the understanding regarding the role of SULT1A1 mutation in cancer development and also xenobiotics management to individuals in the different treatment stages.

Unveiling the Structural Insights into the Selective Inhibition of Protein Kinase D1.

BACKGROUND: Although protein kinase D1 (PKD1) has been proved to be an efficient target for anticancer drug development, lack of structural details and substrate binding mechanisms are the main obstacles for the development of selective inhibitors with therapeutic benefits. OBJECTIVE: The present study described the in silico dynamics behaviors of PKD1 in binding with selective and non-selective inhibitors and revealed the critical binding site residues for the selective kinase inhibition. METHODS: Here, the three dimensional model of PKD1 was initially constructed by homology modeling along with binding site characterization to explore the non-conserved residues. Subsequently, two known inhibitors were docked to the catalytic site and the detailed ligand binding mechanisms and post binding dyanmics were investigated by molecular dynamics simulation and binding free energy calculations. RESULTS: According to the binding site analysis, PKD1 serves several non-conserved residues in the G-loop, hinge and catalytic subunits. Among them, the residues including Leu662, His663, and Asp665 from hinge region made polar interactions with selective PKD1 inhibitor in docking simulation, which were further validated by the molecular dynamics simulation. Both inhibitors strongly influenced the structural dynamics of PKD1 and their computed binding free energies were in accordance with experimental bioactivity data. CONCLUSION: The identified non-conserved residues likely to play critical role on molecular reorganization and inhibitor selectivity. Taken together, this study explained the molecular basis of PKD1 specific inhibition, which may help to design new selective inhibitors for better therapies to overcome cancer and PKD1 dysregulated disorders.

Structure-based identification of potent VEGFR-2 inhibitors from in vivo metabolites of a herbal ingredient.

Vascular endothelial growth factor receptor-2 (VEGFR-2) is one of the regulatory elements of angiogenesis that is expressed highly in various diseases and is also essential for solid tumor growth. The present study was aimed at identifying potent inhibitors of VEGFR-2 by considering herbal secondary metabolites; as natural molecules are less toxic than synthetic derivatives. A structure-based virtual screening protocol consisting of molecular docking, MM-GBSA and ADME/T analysis was initially used to screen a library of in vivo metabolites of the herbal ingredient. Using a fixed cutoff value, four potent virtual hits were identified from molecular docking, ADME/T and binding affinity calculations, which were considered further for molecular dynamics (MD) simulation to broadly describe the binding mechanisms to VEGFR-2. The results suggested that these molecules have high affinity for the catalytic region of VEGFR-2, and form strong hydrophobic and polar interactions with the amino acids involved in the binding site of ATP and linker regions of the catalytic site. Subsequently, the stability of the docked complexes and binding mechanisms were evaluated by MD simulations, and the energy of binding was calculated through MM-PBSA analysis. The results uncovered two virtual hits, designated ZINC14762520 and ZINC36470466, as VEGFR-2 inhibitors, and suggested that they bind to kinase domain in an ATP-competitive manner. These virtual hits will offer a suitable starting point for the further design of their various analogs, allowing a rational search for more effective inhibitors in the future. Graphical abstract.

Identification and structural characterization of deleterious non-synonymous single nucleotide polymorphisms in the human SKP2 gene.

In SCF (Skp, Cullin, F-box) ubiquitin-protein ligase complexes, S-phase kinase 2 (SKP2) is one of the major players of F-box family, that is responsible for the degradation of several important cell regulators and tumor suppressor proteins. Despite of having significant evidence for the role of SKP2 on tumorgenesis, there is a lack of available data regarding the effect of non-synonymous polymorphisms. In this communication, the structural and functional consequences of non-synonymous single nucleotide polymorphisms (nsSNPs) of SKP2 have been reported by employing various computational approaches and molecular dynamics simulation. Initially, several computational tools like SIFT, PolyPhen-2, PredictSNP, I-Mutant 2.0 and ConSurf have been implicated in this study to explore the damaging SNPs. In total of 172 nsSNPs, 5 nsSNPs were identified as deleterious and 3 of them were predicted to be decreased the stability of protein. Guided from ConSurf analysis, P101L (rs761253702) and Y346C (rs755010517) were categorized as the highly conserved and functional disrupting mutations. Therefore, these mutations were subjected to three dimensional model building and molecular dynamics simulation study for the detailed structural consequences upon the mutations. The study revealed that P101L and Y346C mutations increased the flexibility and changed the structural dynamics. As both these mutations are located in the most functional regions of SKP2 protein, these computational insights might be helpful to consider these nsSNPs for wet-lab confirmatory analysis as well as in rationalizing future population based studies and structure based drug design against SKP2.

Prospecting and Structural Insight into the Binding of Novel Plant-Derived Molecules of Leea indica as Inhibitors of BACE1.

BACKGROUND: Alzheimer disease (AD) can be considered as the most common age related neurodegenerative disorder and also an important cause of death in elderly patients. A number of studies showed the correlation of this disease pathology with BACE1 inhibitor and it is also evident that BACE1 inhibitor can function as a very potent strategy in treating AD. METHODS: In this present study, we aimed to prospect for novel plant-derived BACE1 inhibitors from Leea indica and to realise structural basis of their interactions and mechanisms using combined molecular docking and molecular dynamics based approaches. An extensive library of Leea indica plant derived molecule was compiled and computationally screened for inhibitory action against BACE1 by using virtual screening approaches. Furthermore, induced fit docking and classical molecular dynamics along with steered molecular dynamics simulations were employed to get insight of the binding mechanisms. RESULTS: Two triterpenoids, ursolic acid and lupeol were identified through virtual screening; wherein, lupeol showed better binding free energy in MM/GBSA, MM/PBSA and MM/GBVI approaches. Furthermore classical and steered dynamics revealed the favourable hydrophobic interactions between the lupeol and the residues of flap or catalytic dyadof BACE1; however, ursolic acid showed disfavorable interactions with the BACE1. CONCLUSION: This study therefore unveiled the potent BACE1 inhibitor from a manually curated dataset of Leea indica molecules, which may provide a novel dimension of designing novel BACE1 inhibitors for AD therapy.

Antidiarrheal and antinociceptive activities of ethanol extract and its chloroform and pet ether fraction of Phrynium imbricatum (Roxb.) leaves in mice.

BACKGROUND: The objective of the study was to evaluate the antidiarrheal and antinociceptive activities of ethanol extract and its chloroform and pet ether fraction of Phrynium imbricatum (Roxb.) leaves in mice. METHODS: In the present study, the dried leaves of P. imbricatum were subjected to extraction with ethanol, and then it was fractioned by chloroform and pet ether solvent. Antidiarrheal effects were tested by using castor oil-induced diarrhea, castor oil-induced enteropooling, and gastrointestinal transit test. Antinociceptive activity was evaluated by using the acetic acid-induced writhing test and formalin-induced paw licking test. RESULTS: The standard drug loperamide (5 mg/kg) showed significant (p<0.001) inhibitory activity against castor oil-induced diarrhea, in which all the examined treatments decreased the frequency of defecation and were found to possess an anti-castor oil-induced enteropooling effect in mice by reducing both weight and volume of intestinal content significantly, and reducing the propulsive movement in castor oil-induced gastrointestinal transit using charcoal meal in mice. The results showed that the ethanol extract of P. imbricatum leaves has significant dose-dependent antinociceptive activity, and among its two different fractions, the pet ether fraction significantly inhibited the abdominal writhing induced by acetic acid and the licking times in formalin test at both phases. CONCLUSIONS: These findings suggest that the plant may be a potential source for the development of a new antinociceptive drug and slightly suitable for diarrhea, as it exhibited lower activity. Our observations resemble previously published data on P. imbricatum leaves.