Identification by Molecular Docking ofHomoisoflavones from Leopoldia comosa as Ligands of Estrogen Receptors

The first report of an Algerian Leopoldia comosa essential oil content and antioxidant assessment

In the current study, we examined the chemical makeup and anti-oxidant potential of an Algerian Leopoldia comosa. The results showed that there were moderate levels of phenols and flavonoids in the crude extract (15.11 ± 0.78 μg GAE/mg and 31.27 ± 2.71 μg QE/mg, respectively). Additionally, the findings showed that both crude extract and EO had moderate antioxidant capabilities (8.74 ± 1.13 mg/ml; 13.18 ± 0.18% and 12.94 ± 0.89%, respectively). Twelve (12) volatile compounds were found in the EO according to GC-MS and GC-FID analyses, with tetrapentacontane (48.25%), 3,7,11,15-tetramethyl-2-hexadecen-1-ol (16.59%), hexatriacontane (9.17%), and 6,10,14-trimethylpentadecan-2-one (8.80%) accounting for the majority of the components. To our knowledge, no earlier studies have looked at the chemical composition of L. comosa oil. These findings might contribute to our understanding of this species' makeup and make it a useful source of food and medicine in the future.

Detection of isoflavones and phytoestrogen-rich plant extracts binding to estrogen receptor β using a yeast-based fluorescent assay

Alchemilla vulgaris L., Trifolium pratense L. and Glycyrrhiza glabra L. are important remedies in traditional medicine, known for many usages, including treating gynecological diseases. Despite folkloric use of the plant materials, there is a lack of scientific data to support their therapeutic application. The aims of the present study were to evaluate the relative binding affinities (RBAs) of plant-derived phytoestrogens for estrogen receptor β (ERβ) using fluorescent biosensor in yeast and to apply this assay for the assessment of the potential of plant materials towards ERs and treatment of estrogen-related disorders. Ligand-binding domain of ERβ fused with yellow fluorescent protein (ERβ LBD-YFP) was expressed in S. cerevisiae and fluorescence was detected by fluorimetry and fluorescence microscopy. Structural basis for experimental results was explored by molecular docking. Yeast-based fluorescent assay was successfully optimized and applied for identification of natural phenolic compounds and phytoestrogen-rich plant extracts that interact with ERβ-LBD, making this biosensor a valuable tool for screening estrogenic potential of a variety of plant extracts. This assay can be used for preliminary testing of plant-derived or fungal extracts, but also other sources of environmental substances with ER-modulating activity in order to assess their possible effects on the female reproductive system.

Combination of plant metabolites hinders starch digestion and glucose absorption while facilitating insulin sensitivity to diabetes

Introduction

Diabetes mellitus (DM) is a common endocrine disease resulting from interactions between genetic and environmental factors. Type II DM (T2DM) accounts for approximately 90% of all DM cases. Current medicines used in the treatment of DM have some adverse or undesirable effects on patients, necessitating the use of alternative medications.

Methods

To overcome the low bioavailability of plant metabolites, all entities were first screened through pharmacokinetic, network pharmacology, and molecular docking predictions. Experiments were further conducted on a combination of antidiabetic phytoactive molecules (rosmarinic acid, RA; luteolin, Lut; resveratrol, RS), along with in vitro evaluation (α-amylase inhibition assay) and diabetic mice tests (oral glucose tolerance test, OGTT; oral starch tolerance test, OSTT) for maximal responses to validate starch digestion and glucose absorption while facilitating insulin sensitivity.

Results

The results revealed that the combination of metabolites achieved all required criteria, including ADMET, drug likeness, and Lipinski rule. To determine the mechanisms underlying diabetic hyperglycemia and T2DM treatments, network pharmacology was used for regulatory network, PPI network, GO, and KEGG enrichment analyses. Furthermore, the combined metabolites showed adequate in silico predictions (α-amylase, α-glucosidase, and pancreatic lipase for improving starch digestion; SGLT-2, AMPK, glucokinase, aldose reductase, acetylcholinesterase, and acetylcholine M2 receptor for mediating glucose absorption; GLP-1R, DPP-IV, and PPAR-γ for regulating insulin sensitivity), in vitro α-amylase inhibition, and in vivo efficacy (OSTT versus acarbose; OGTT versus metformin and insulin) as nutraceuticals against T2DM.

Discussion

The results demonstrate that the combination of RA, Lut, and RS could be exploited for multitarget therapy as prospective antihyperglycemic phytopharmaceuticals that hinder starch digestion and glucose absorption while facilitating insulin sensitivity.

Computational Screening of Some Phytochemicals to Identify Best Modulators for Ligand Binding Domain of Estrogen Receptor Alpha

OBJECTIVE

The peculiar aim of this study is to discover and identify the most effective and potential inhibitors against the most influential target ERα receptor by in silico studies of 45 phytochemicals from six diverse ayurvedic medicinal plants.

METHODS

The molecular docking investigation was carried out by the genetic algorithm program of AutoDock Vina. The molecular dynamic (MD) simulation investigations were conducted using the Desmond tool of Schrödinger molecular modelling. This study identified the top ten highest binding energy phytochemicals that were taken for drug-likeness test and ADMET profile prediction with the help of the web-based server QikpropADME.

RESULTS

Molecular docking study revealed that ellagic acid (-9.3 kcal/mol), emodin (-9.1 kcal/mol), rhein (-9.1 kcal/mol), andquercetin (-9.0 kcal/mol) phytochemicals showed similar binding affinity as standard tamoxifen towards the target protein ERα. MD studies showed that all four compounds possess comparatively stable ligand-protein complexes with ERα target compared to the tamoxifen-ERα complex. Among the four compounds, phytochemical rhein formed a more stable complex than standard tamoxifen. ADMET studies for the top ten highest binding energy phytochemicals showed a better safety profile.

CONCLUSION

Additionally, these compounds are being reported for the first time in this study as possible inhibitors of ERα for treating breast cancer, according to the notion of drug repurposing. Hence, these phytochemicals can be further studied and used as a parent core molecule to develop innovative lead molecules for breast cancer therapy.

Dissecting CYP1A2 Activation by Arylalkanoic Acid Prodrugs toward the Development of Anti-Inflammatory Agents

Arylalkane-derived prodrugs of arylacetic acids are a small group of substances that have long been known for their anti-inflammatory action. Despite their ease of synthesis and good potential for the development of new potent and safe anti-inflammatory agents, this group of substances has not received much attention from researchers so far. Therefore, representative arylalkane derivatives were investigated through molecular docking techniques to verify the possible hepatic activation mode toward active metabolites by CYP1A2. In this regard, arylalkanoic acid prodrugs were docked with a crystallographic structure of human CYP1A2, in which the enzyme is co-crystallized with the selective competitive inhibitor α-naphthoflavone BHF. Of note, all the examined compounds proved capable of interacting with the enzyme active site in a manner similar to Nabumetone, thus confirming that a productive metabolic transformation is feasible. On the basis of these findings, it is possible to argue that subtle differences in the way CYP1A2 accommodates the ligands depend on the fine details of their molecular structures. Overall, these data suggest that compounds simply formed by an aromatic moiety bearing an appropriate alkane-derived chain could lead to innovative anti-inflammatory agents.

Lavandula angustifolia mill. (Lamiaceae) ethanol extract and its main constituents as promising agents for the treatment of metabolic disorders: chemical profile, in vitro biological studies, and molecular docking

Lavandula angustifolia Mill. (lavender) is one of the most used medicinal plants. Herein, we chemically characterised and investigated the antioxidant properties and the capability to inhibit key enzymes for the treatment of type 2 diabetes (TD2) and obesity such as pancreatic lipase, α-glucosidase, and α-amylase of the ethanolic extract of two lavender samples (La1 and La2) from southern Italy. Both extracts significantly inhibited α-glucosidase, while La1 inhibited α-amylase and lipase more effectively than La2. To investigate whether these properties could be due to a direct interaction of the main constituents of the extracts with the targeted enzymes, molecular docking studies have been performed. As a result, the selected compounds were able to interact with the key residues of the binding site of the three proteins, thus supporting biological data. Current findings indicate the new potential of lavender ethanolic extract for the development of novel agents for T2D and obesity.

The interaction of tryptophan enantiomers with model membranes is modulated by polar head type and physical state of phospholipids

The mutual influence of chiral bioactive molecules and supramolecular assemblies is currently being studied in many research fields, including medical-pharmaceutical applications. Model membranes of phospholipids, such as the zwitterionic dipalmitoylphosphatidylcholine (DPPC) and the anionic dipalmitoylphosphatidylglycerol (DPPG), interact with a variety of chiral compounds that include amino acids. In this work, the interaction of tryptophan enantiomers, L-Trp and D-Trp, on DPPC and DPPG bilayers was investigated by using differential scanning calorimetry, attenuated total reflectance-Fourier transform infrared and spin-label electron spin resonance spectroscopies as well as molecular docking simulations. The results show that Trp enantiomers slightly perturb the bilayer thermotropic phase transitions. For both membranes, O atoms in the carbonyl groups have a propensity to act as acceptors of a (weak) hydrogen bond. The Trp chiral forms also promote formation of hydrogen bonds and/or hydration in the PO₂^- moiety of the phosphate group, especially for the DPPC bilayer. In contrast, they interact more closely with the glycerol group of DPPG polar head. Only for DPPC bilayers, both enantiomers increase the packing of the first hydrocarbon chain segments for temperatures through the gel state, whereas they do not affect the lipid chain order and mobility in the fluid state. The results are consistent with a Trp association in the upper region of the bilayers without permeation in the innermost hydrophobic region. The findings suggest that neutral and anionic lipid bilayers are differently sensitive to amino acid chirality.

Environmental estrogens shape disease susceptibility

Along with industrialization, the environment is flooded with endocrine-disrupting chemicals, among which substances with estrogenic effects have attracted widespread attention in medical research. In terms of molecular mechanism, environmental estrogens can cause endocrine and metabolic disorders; interfere with multiple carcinogenic pathways; and lead to neurobehavioral disorders, reproductive toxicity, and multi- or trans-generational phenotypic abnormalities. However, many of the results from molecular and animal experiments were not supported by epidemiology, which may be related to the existence of a window of sensitivity to environmental estrogen exposure over the human life course, where the consequences of exposure vary greatly from other times. This paper will introduce the main sources of environmental estrogens, their toxicity and mechanisms of action, the status of research on several representative types, and current monitoring and treatment methods. We also discussed the extent of the risks to human health dialectically in the context of laboratory and epidemiological findings, with a view to better addressing these chemicals to which we are constantly exposed.

Estrogenic flavonoids and their molecular mechanisms of action

Flavonoids are a major group of phytoestrogens associated with physiological effects, and ecological and social impacts. Although the estrogenic activity of flavonoids was reported by researchers in the fields of medical, environmental and food studies, their molecular mechanisms of action have not been comprehensively reviewed. The estrogenic activity of the respective classes of flavonoids, anthocyanidins/anthocyanins, 2-arylbenzofurans/3-arylcoumarins/α-methyldeoxybenzoins, aurones/chalcones/dihydrochalcones, coumaronochromones, coumestans, flavans/flavan-3-ols/flavan-4-ols, flavanones/dihydroflavonols, flavones/flavonols, homoisoflavonoids, isoflavans, isoflavanones, isoflavenes, isoflavones, neoflavonoids, oligoflavonoids, pterocarpans/pterocarpenes, and rotenone/rotenoids, was summarized through a comprehensive literature search, and their structure-activity relationship, biological activities, signaling pathways, and applications were discussed. Although the respective classes of flavonoids contained at least one chemical mimicking estrogen, the mechanisms varied, such as those with estrogenic, anti-estrogenic, non-estrogenic, and biphasic activities, and additional activities through crosstalk/bypassing, which exert biological activities through cell signaling pathways. Such mechanistic variations of estrogen action are not limited to flavonoids and are observed among other broad categories of chemicals, thus this group of chemicals can be termed as the "estrogenome". This review article focuses on the connection of estrogen action mainly between the outer and the inner environments, which represent variations of chemicals and biological activities/signaling pathways, respectively, and form the basis to understand their applications. The applications of chemicals will markedly progress due to emerging technologies, such as artificial intelligence for precision medicine, which is also true of the study of the estrogenome including estrogenic flavonoids.

Intrinsically Disordered Chromatin Protein NUPR1 Binds to the Enzyme PADI4

The nuclear protein 1 (NUPR1) is an intrinsically disordered protein involved in stress-mediated cellular conditions. Its paralogue nuclear protein 1-like (NUPR1L) is p53-regulated, and its expression down-regulates that of the NUPR1 gene. Peptidyl-arginine deiminase 4 (PADI4) is an isoform of a family of enzymes catalyzing arginine to citrulline conversion; it is also involved in stress-mediated cellular conditions. We characterized the interaction between NUPR1 and PADI4 in vitro, in silico, and in cellulo. The interaction of NUPR1 and PADI4 occurred with a dissociation constant of 18 ± 6 μM. The binding region of NUPR1, mapped by NMR, was a hydrophobic polypeptide patch surrounding the key residue Ala33, as pinpointed by: (i) computational results; and, (ii) site-directed mutagenesis of residues of NUPR1. The association between PADI4 and wild-type NUPR1 was also assessed in cellulo by using proximity ligation assays (PLAs) and immunofluorescence (IF), and it occurred mainly in the nucleus. Moreover, binding between NUPR1L and PADI4 also occurred in vitro with an affinity similar to that of NUPR1. Molecular modelling provided information on the binding hot spot for PADI4. This is an example of a disordered partner of PADI4, whereas its other known interacting proteins are well-folded. Altogether, our results suggest that the NUPR1/PADI4 complex could have crucial functions in modulating DNA-repair, favoring metastasis, or facilitating citrullination of other proteins.

Promising Perspectives of the Antiproliferative GPER Inverse Agonist ERα17p in Breast Cancer

The estrogen receptor α (ERα) corresponds to a large platform in charge of the recruitment of a panel of molecules, including steroids and related heterocyclic derivatives, oligonucleotides, peptides and proteins. Its 295-311 region is particularly targeted by post-translational modifications, suggesting that it could be crucial for the control of transcription. In addition to anionic phospholipids, the ERα 295-311 fragment interacts with Ca²⁺-calmodulin, the heat shock protein 70 (Hsp70), ERα and possibly importins. More recently, we have demonstrated that it is prone to interacting with the G-protein-coupled estrogen receptor (GPER). In light of these observations, the pharmacological profile of the corresponding peptide, namely ERα17p, has been explored in breast cancer cells. Remarkably, it exerts apoptosis through GPER and induces a significant decrease (more than 50%) of the size of triple-negative breast tumor xenografts in mice. Herein, we highlight not only the promising therapeutic perspectives in the use of the first peptidic GPER modulator ERα17p, but also the opportunity to modulate GPER for clinical purposes.

Hibiscus sabdariffa anthocyanins are potential modulators of estrogen receptor alpha activity with favourable toxicology: a computational analysis using molecular docking, ADME/Tox prediction, 2D/3D QSAR and molecular dynamics simulation

The estrogen hormone receptor (ER) mediated gene expression mainly regulate the development and physiology of the primary and secondary reproductive system alongside bone-forming, metabolism and behaviour. Over-expressed ER is associated with several pathological conditions and play a crucial role in breast cancer occurrence, progression and metastasis. Hibiscus sabdariffa L. or roselle is a rich source of naturally occurring polyphenolic compounds that reportedly have robust estrogenic activity. However, the estrogen-like ingredient of the plant remains ambiguous. This study has screened a library of already recorded and less-explored compounds of Hibiscus sabdariffa for their estrogen receptor binding affinity and safety using a suite of computational methods that include protein-ligand docking, ADME and Toxicity prediction, and 2D/3D QSAR. The study revealed that the estrogen-receptor binding potential of Pelargonidin, Delphinidin, Cyanidin, and Hibiscetin are more efficient than popular breast cancer drugs, Tamoxifen and Raloxifene. Besides, the compounds exhibited favourable toxicological parameters with potent bioactivity towards binding ER-α subunit. Thus, these compounds can serve as prototypes for designing novel Selective Estrogen Receptor Modulator molecules with a few structural modifications. This is the first report exploring the phytochemical basis of estrogenic activity of Hibiscus sabdariffa L.Communicated by Ramaswamy H. Sarma.

Human Enzyme PADI4 Binds to the Nuclear Carrier Importin α3

PADI4 is a peptidyl-arginine deiminase (PADI) involved in the conversion of arginine to citrulline. PADI4 is present in macrophages, monocytes, granulocytes, and several cancer cells. It is the only PADI family member observed within both the nucleus and the cytoplasm. PADI4 has a predicted nuclear localization sequence (NLS) comprising residues Pro56 to Ser83, to allow for nuclear translocation. Recent predictors also suggest that the region Arg495 to Ile526 is a possible NLS. To understand how PADI4 is involved in cancer, we studied the ability of intact PADI4 to bind importin α3 (Impα3), a nuclear transport factor that plays tumor-promoting roles in several cancers, and its truncated species (ΔImpα3) without the importin-binding domain (IBB), by using fluorescence, circular dichroism (CD), and isothermal titration calorimetry (ITC). Furthermore, the binding of two peptides, encompassing the first and the second NLS regions, was also studied using the same methods and molecular docking simulations. PADI4 interacted with both importin species, with affinity constants of ~1–5 µM. The isolated peptides also interacted with both importins. The molecular simulations predict that the anchoring of both peptides takes place in the major binding site of Impα3 for the NLS of cargo proteins. These findings suggest that both NLS regions were essentially responsible for the binding of PADI4 to the two importin species. Our data are discussed within the framework of a cell mechanism of nuclear transport that is crucial in cancer.

Interaction of letrozole and its degradation products with aromatase: chemometric assessment of kinetics and structure-based binding validation

Letrozole is one of the most prescribed drugs for the treatment of breast cancer in post-menopausal women, and it is endowed with selective peripheral aromatase inhibitory activity. The efficacy of this drug is also a consequence of its long-lasting activity, likely due to its metabolic stability. The reactivity of cyano groups in the letrozole structure could, however, lead to chemical derivatives still endowed with residual biological activity. Herein, the chemical degradation process of the drug was studied by coupling multivariate curve resolution and spectrophotometric methodologies in order to assess a detailed kinetic profile. Three main derivatives were identified after drug exposure to different degradation conditions, consisting of acid-base and oxidative environments and stressing light. Molecular docking confirmed the capability of these compounds to accommodate into the active site of the enzyme, suggesting that the sustained inhibitory activity of letrozole may be at least in part attributed to the degradation compounds.

Experimental, molecular docking and molecular dynamic studies of natural products targeting overexpressed receptors in breast cancer

Natural compounds are proper tools for inhibiting cancer cell proliferation. Hence, the search for these ligands of overexpressed receptors in breast cancer has been a competitive challenge recently and opens new avenues for drug discovery. In this research, we have investigated molecular interactions between natural products and overexpressed receptors in breast cancer using molecular docking and dynamic simulation approaches followed by extraction of the best ligand from Citrus limetta and developing for nanoscale encapsulation composed of soy lecithin using a sonicator machine. The encapsulation process was confirmed by DLS and TEM analyses. Anticancer activity was also examined using MTT method. Among the investigated natural compounds, hesperidin was found to bind to specific targets with stronger binding energy. The molecular dynamics results indicated that the hesperidin-MCL-1 complex is very stable at 310.15 K for 200 ns. The RP-HPLC analysis revealed that the purity of extracted hesperidin was 98.8% with a yield of 1.72%. The results of DLS and TEM showed a strong interaction between hesperidin and lecithin with an entrapped efficiency of 92.02 ± 1.08%. Finally, the cytotoxicity effect of hesperidin was increased against the MDA-MB-231 cell line with an IC50 value of 62.93 μg/mL after encapsulation, whereas no significant effect against the MCF10A cell line. We showed for the first time that hesperidin is a flexible and strong ligand for the MCL-1 receptor. Also, it has the in vitro ability to kill the MDA-MB-231 cell lines without having a significant effect on the MCF10A cell lines. Therefore, hesperidin could be used as a food ingredient to generate functional foods.

Pangenomes as a Resource to Accelerate Breeding of Under-Utilised Crop Species

Pangenomes are a rich resource to examine the genomic variation observed within a species or genera, supporting population genetics studies, with applications for the improvement of crop traits. Major crop species such as maize (Zea mays), rice (Oryza sativa), Brassica (Brassica spp.), and soybean (Glycine max) have had pangenomes constructed and released, and this has led to the discovery of valuable genes associated with disease resistance and yield components. However, pangenome data are not available for many less prominent crop species that are currently under-utilised. Despite many under-utilised species being important food sources in regional populations, the scarcity of genomic data for these species hinders their improvement. Here, we assess several under-utilised crops and review the pangenome approaches that could be used to build resources for their improvement. Many of these under-utilised crops are cultivated in arid or semi-arid environments, suggesting that novel genes related to drought tolerance may be identified and used for introgression into related major crop species. In addition, we discuss how previously collected data could be used to enrich pangenome functional analysis in genome-wide association studies (GWAS) based on studies in major crops. Considering the technological advances in genome sequencing, pangenome references for under-utilised species are becoming more obtainable, offering the opportunity to identify novel genes related to agro-morphological traits in these species.

In Silico Studies of Tumor Targeted Peptide-Conjugated Natural Products for Targeting Over-Expressed Receptors in Breast Cancer Cells Using Molecular Docking, Molecular Dynamics and MMGBSA Calculations

In this work, in silico studies were carried out for the design of diterpene and polyphenol-peptide conjugates to potentially target over-expressed breast tumor cell receptors. Four point mutations were induced into the known tumor-targeting peptide sequence YHWYGYTPQN at positions 1, 2, 8 and 10, resulting in four mutated peptides. Each peptide was separately conjugated with either chlorogenate, carnosate, gallate, or rosmarinate given their known anti-tumor activities, creating dual targeting compounds. Molecular docking studies were conducted with the epidermal growth factor receptor (EGFR), to which the original peptide sequence is known to bind, as well as the estrogen receptor (ERα) and peroxisome proliferator-activated receptor (PPARα) using both Autodock Vina and FireDock. Based on docking results, peptide conjugates and peptides were selected and subjected to molecular dynamics simulations. MMGBSA calculations were used to further probe the binding energies. ADME studies revealed that the compounds were not CYP substrates, though most were Pgp substrates. Additionally, most of the peptides and conjugates showed MDCK permeability. Our results indicated that several of the peptide conjugates enhanced binding interactions with the receptors and resulted in stable receptor-ligand complexes; Furthermore, they may successfully target ERα and PPARα in addition to EGFR and may be further explored for synthesis and biological studies for therapeutic applications.

Polyphenols from Citrus Tacle® Extract Endowed with HMGCR Inhibitory Activity: An Antihypercholesterolemia Natural Remedy

Tacle^® is a citrus fruit obtained from the crossbreeding of Clementine and Tarocco cultivars. This fruit retains a promising nutraceutical potential most likely due to a high content in polyphenols, among which the main constituents are the two glycosides naringin and hesperidin. Herein, we evaluated, through an in vitro assay, the capability of Tacle extracts to inhibit the hydroxymethylglutaryl-CoA reductase enzyme, which plays a key role in cholesterol biosynthesis. The results obtained spurred us to investigate whether the anti-enzymatic activity observed may be due to a direct interaction of aglycones naringenin and hesperetin with the enzyme catalytic site. Molecular docking simulations indicated that these two compounds are able to anchor to the protein with binding modes and affinities similar to those found for statins, which represent mainstream medications against hypercholesterolemia. The overall results showed an interesting nutraceutical potential of Tacle, suggesting that its extract could be used for dietary supplementation in the treatment of moderate hypercholesterolemia.

Sub-Micromolar Inhibition of SARS-CoV-2 3CLpro by Natural Compounds

Inhibiting the main protease 3CLpro is the most common strategy in the search for antiviral drugs to fight the infection from SARS-CoV-2. We report that the natural compound eugenol is able to hamper in vitro the enzymatic activity of 3CLpro, the SARS-CoV-2 main protease, with an inhibition constant in the sub-micromolar range (K_i = 0.81 μM). Two phenylpropene analogs were also tested: the same effect was observed for estragole with a lower potency (K_i = 4.1 μM), whereas anethole was less active. The binding efficiency index of these compounds is remarkably favorable due also to their small molecular mass (MW < 165 Da). We envision that nanomolar inhibition of 3CLpro is widely accessible within the chemical space of simple natural compounds.

Experimental and molecular docking studies of estrogen-like and anti-osteoporosis activity of compounds in Fructus Psoraleae

ETHNOPHARMACOLOGICAL RELEVANCE

Fructus Psoraleae (FP), dry mature fruits of Cullen corylifolium (L.) Medik., has been used clinically to treat kidney yang deficiency-induced impotence, asthma and cold pain in waist and knee caused by kidney deficiency. A study of the source of the significant kidney-enhancing effect of FP revealed that it may be due to its strong estrogen-like activity.

AIM OF THE STUDY

This study aimed to investigate the estrogen-like activity of the FP extract and 13 bioactive compounds in it, as well as the mechanisms underlying their estrogen-like and anti-osteoporosis activities.

MATERIALS AND METHODS

The estrogen-like activities of the 75% ethanol-only FP extract, and 75% ethanol plus petroleum ether, ethyl acetate, n-butanol or water FP extracts were each measured using Cell Counting Kit-8 (CCK-8) and luciferase reporter gene assays. The compounds were identified by high-performance liquid chromatography analysis. The activation of estrogen receptor signaling by the compounds was compared with that by estradiol (E₂) using the molecular docking software MOE-Dock 2008.10. The activation of the ER-Wnt-β-catenin signaling pathway was investigated using an alkaline phosphatase (ALP) assay, qPCR analysis and Western blot analysis.

RESULTS

The results revealed that the 75% ethanol plus ethyl acetate extract showed the highest estrogen-like activity among the four 75% ethanol extract fractions (further extracted with petroleum ether, ethyl acetate, n-butanol or water). Some compounds in FP showed strong estrogenic effect and anti-osteoporosis activity, and activated the Wnt-β-catenin pathway. The isoflavone compound was the most active.

CONCLUSIONS

This study demonstrated that FP has a strong estrogen-like activity and some of its component compounds have anti-osteoporosis activity by activating the ER-Wnt-β-catenin signaling pathway. Our detections provide a new insight into the mechanisms underlying the estrogen-like and anti-osteoporosis activities of FP, as well as a better understanding of structure effects.

Toward Multitasking Pharmacological COX-Targeting Agents: Non-Steroidal Anti-Inflammatory Prodrugs with Antiproliferative Effects

The antitumor activity of certain anti-inflammatory drugs is often attributed to an indirect effect based on the inhibition of COX enzymes. In the case of anti-inflammatory prodrugs, this property could be attributed to the parent molecules with mechanism other than COX inhibition, particularly through formulations capable of slowing down their metabolic conversion. In this work, a pilot docking study aimed at comparing the interaction of two prodrugs, nabumetone (NB) and its tricyclic analog 7-methoxy-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-one (MC), and their common active metabolite 6-methoxy-2-naphthylacetic acid (MNA) with the COX binding site, was carried out. Cytotoxicity, cytofluorimetry, and protein expression assays on prodrugs were also performed to assess their potential as antiproliferative agents that could help hypothesize an effective use as anticancer therapeutics. Encouraging results suggest that the studied compounds could act not only as precursors of the anti-inflammatory metabolite, but also as direct antiproliferative agents.

Exploration of therapeutic applicability and different signaling mechanism of various phytopharmacological agents for treatment of breast cancer

BACKGROUND

Cancer is one of the most dreaded diseases characterized by uncontrolled proliferation of abnormal cells that occurs due to impairment of cell division and apoptosis process. Cancer is categorized into several types on the basis of affected organs and breast cancer (BC) is the most predominant cause of mortality among women. Although, several synthetic and semi-synthetic therapies have been developed for the treatment of BC but they exhibit numerous serious adverse effects therefore; pharmacological agents with fewer/no side effects need to be explored. Plants and phytoconstituents perhaps fulfill the aforementioned requirement and could serve as a potential and alternative therapy for BC treatment. The ongoing biomedical research, clinical trials and number of patents granted have further boosted the acceptance of the plants and plant-derived constituents in the effective treatment of BC.

PURPOSE OF STUDY

Various treatment strategies such as checkpoint inhibitors, targeting micro RNA, apoptotic pathway, BRCA-1 gene, P₅₃ protein, P13K/Akt/mTOR pathway, notch signaling pathway, hedgehog/gli-1 signaling pathway, poly-ADP ribose polymerase inhibitors, mitogen-activated protein kinase inhibitors etc. are available for BC. In addition to these synthetic and semi-synthetic drug therapies, several natural constituents such as alkaloids, sesquiterpenes, polyphenols, flavonoids and diterpenoids from medicinal plants, vegetables and fruits are reported to possess promising anti-cancer activity. The purpose of the present review is to highlight the various signaling pathways through which plants/herbs show the anti-cancer potential especially against the BC.

STUDY DESIGN

The literature for the present study was collected from various databases such as Pubmed, Scopus, Chemical Abstracts, Medicinal and aromatic plant abstracts, Web of Science etc. The different patent databases were also reviewed for the anti-cancer (BC) potential of the particular herbs/plants and their formulations.

RESULT AND CONCLUSION

In this review, we have discussed the number of plants along with their patents of different herbal formulations which are being used for the treatment of BC and other types of cancers. We have also delineated the different signaling mechanisms through which they inhibit the growth of BC cells. In nutshell, we can conclude that large numbers of herbs or their extracts are reported for the treatment of BC. But still, there is further need for research in-depth to translate the use of natural products clinically BC treatment.

The nuclear localization sequence of the epigenetic factor RYBP binds to human importin α3

RYBP (Ring1 and YY1 binding protein, UniProt ID: Q8N488) is an epigenetic factor with a key role during embryonic development; it does also show an apoptotic function and an ubiquitin binding activity. RYBP is an intrinsically disordered protein (IDP), with a Zn-finger domain at its N-terminal region, which folds upon binding to DNA. It is predicted that RYBP has a nuclear localization sequence (NLS), comprising residues Asn58 to Lys83, to allow for nuclear translocation. We studied in this work the ability of intact RYBP to bind Impα3 and its truncated species, ΔImpα3, without the importin binding domain (IBB), by using fluorescence and circular dichroism (CD). Furthermore, the binding of the peptide matching the isolated NLS region of RYBP (NLS-RYBP) was also studied using the same methods and isothermal titration calorimetry (ITC), and in silico molecular docking. Moreover, we carried out experiments with NLS-RYBP in the absence or in the presence of NaCl (140 mM). Our results show that RYBP interacted with Impα3 and ΔImpα3, causing protein precipitation. The NLS-RYBP also interacted with both importin species (dissociation constant in the low micromolar range), at low or high ionic strength, as shown by intrinsic fluorescence and ITC. These findings indicate that the NLS region, which was mainly unfolded in isolation in solution, was essentially responsible for the binding of RYBP to each of the importin species. Furthermore, the molecular simulations predict that the anchoring of NLS-RYBP takes place in the major binding site for the NLS of cargo proteins bound to Impα3. Taken together, our findings pinpoint the theoretical predictions of the NLS region in RYBP and, more importantly, suggest that this IDP relies on an importin for its nuclear translocation.

The chromogranin A1-373 fragment reveals how a single change in the protein sequence exerts strong cardioregulatory effects by engaging neuropilin-1

AIM

Chromogranin A (CgA), a 439-residue long protein, is an important cardiovascular regulator and a precursor of various bioactive fragments. Under stressful/pathological conditions, CgA cleavage generates the CgA_1-373 proangiogenic fragment. The present work investigated the possibility that human CgA_1-373 influences the mammalian cardiac performance, evaluating the role of its C-terminal sequence.

METHODS

Haemodynamic assessment was performed on an ex vivo Langendorff rat heart model, while mechanistic studies were performed using perfused hearts, H9c2 cardiomyocytes and in silico.

RESULTS

On the ex vivo heart, CgA_1-373 elicited direct dose-dependent negative inotropism and vasodilation, while CgA_1-372 , a fragment lacking the C-terminal R₃₇₃ residue, was ineffective. Antibodies against the PGPQLR₃₇₃ C-terminal sequence abrogated the CgA_1-373 -dependent cardiac and coronary modulation. Ex vivo studies showed that CgA_1-373 -dependent effects were mediated by endothelium, neuropilin-1 (NRP1) receptor, Akt/NO/Erk1,2 pathways, nitric oxide (NO) production and S-nitrosylation. In vitro experiments on H9c2 cardiomyocytes indicated that CgA_1-373 also induced eNOS activation directly on the cardiomyocyte component by NRP1 targeting and NO involvement and provided beneficial action against isoproterenol-induced hypertrophy, by reducing the increase in cell surface area and brain natriuretic peptide (BNP) release. Molecular docking and all-atom molecular dynamics simulations strongly supported the hypothesis that the C-terminal R₃₇₃ residue of CgA_1-373 directly interacts with NRP1.

CONCLUSION

These results suggest that CgA_1-373 is a new cardioregulatory hormone and that the removal of R₃₇₃ represents a critical switch for turning "off" its cardioregulatory activity.

Cateslytin abrogates lipopolysaccharide-induced cardiomyocyte injury by reducing inflammation and oxidative stress through toll like receptor 4 interaction

Global public health is threatened by new pathogens, antimicrobial resistant microorganisms and a rapid decline of conventional antimicrobials efficacy. Thus, numerous medical procedures become life-threating. Sepsis can lead to tissue damage such as myocardium inflammation, associated with reduction of contractility and diastolic dysfunction, which may cause death. In this perspective, growing interest and attention are paid on host defence peptides considered as new potential antimicrobials. In the present study, we investigated the physiological and biochemical properties of Cateslytin (Ctl), an endogenous antimicrobial chromogranin A-derived peptide, in H9c2 cardiomyocytes exposed to lipopolysaccharide (LPS) infection. We showed that both Ctl (L and D) enantiomers, but not their scrambled counterparts, significantly increased cardiomyocytes viability following LPS, even if L-Ctl was effective at lower concentration (1 nM) compared to D-Ctl (10 nM). L-Ctl mitigated LPS-induced LDH release and oxidative stress, as visible by a reduction of MDA and protein carbonyl groups content, and by an increase of SOD activity. Molecular docking simulations strongly suggested that L-Ctl modulates TLR4 through a direct binding to the partner protein MD-2. Molecular analyses indicated that the protection mediated by L-Ctl against LPS-evoked sepsis targeted the TLR4/ERK/JNK/p38-MAPK pathway, regulating NFkB p65, NFkB p52 and COX2 expression and repressing the mRNA expression levels of the LPS-induced proinflammatory factors IL-1β, IL-6, TNF-α and NOS2. These findings indicate that Ctl could be considered as a possible candidate for the development of new antimicrobials strategies in the treatment of myocarditis. Interestingly, L-enantiomeric Ctl showed remarkable properties in strengthening the anti-inflammatory and anti-oxidant effects on cardiomyocytes.

Intrinsically disordered protein NUPR1 binds to the armadillo-repeat domain of Plakophilin 1

Plakophilin 1 (PKP1), a member of the armadillo repeat family of proteins, is a scaffold component of desmosomes, which are key structural components for cell-cell adhesion. However, PKP1 can be also found in the nucleus of several cells. NUPR1 is an intrinsically disordered protein (IDP) that localizes throughout the whole cell, and intervenes in the development and progression of several cancers. In this work, we studied the binding between PKP1 and NUPR1 by using several in vitro biophysical techniques and in cellulo approaches. The interaction occurred with an affinity in the low micromolar range (~10 μM), and involved the participation of at least one of the tryptophan residues of PKP1 (as shown by fluorescence and molecular docking). The binding region of NUPR1, mapped by NMR and molecular modelling, was a polypeptide patch at the 30s region of its sequence. The association between PKP1 and NUPR1 also occurred in cellulo and was localized in the nucleus, as tested by protein ligation assays (PLAs). We hypothesize that NUPR1 plays an active role in carcinogenesis modulating the function of PKP1.

Muscari comosum L. Bulb Extracts Modulate Oxidative Stress and Redox Signaling in HepG2 Cells

Muscari comosum L. bulbs are commonly used as food in South Italy and also in folk medicine. By evaluating in vitro antioxidant activity and biological activities of their aqueous and methanol extracts, we shed light on the potential role, including both the nutraceutical and health benefits, of this plant. Total polyphenol content (TPC) and total flavonoid content (TFC) were evaluated by the Folin-Ciocalteu method and by the aluminum chloride method, respectively. Antioxidant activity was investigated by three in vitro assays and relative antioxidant capacity index (RACI) was calculated to compare results obtained by different tests. The extracts were tested to evaluate their possible involvement in redox homeostasis, using the human hepatoma (HepG2) cell line used as model. The extracts exhibited concentration/solvent dependent radical scavenging activity, as well as dysregulation of some genes involved in redox pathways by promoting Nrf2, SOD-2, GPX1, ABCC6 and ABCG2 expression. NMR metabolomics analysis suggests that HepG2 cells treated with Muscari comosum extracts experience changes in some metabolites involved in various metabolic pathways.

The muscle-relaxing C-terminal peptide from troponin I populates a nascent helix, facilitating binding to tropomyosin with a potent therapeutic effect

The conserved C-terminal end segment of troponin I (TnI) plays a critical role in regulating muscle relaxation. This function is retained in the isolated C-terminal 27 amino acid peptide (residues 184-210) of human cardiac TnI (HcTnI-C27): When added to skinned muscle fibers, HcTnI-C27 reduces the Ca2+-sensitivity of activated myofibrils and facilitates relaxation without decreasing the maximum force production. However, the underlying mechanism of HcTnI-C27 function is unknown. We studied the conformational preferences of HcTnI-C27 and a myopathic mutant, Arg192His, (HcTnI-C27-H). Both peptides were mainly disordered in aqueous solution with a nascent helix involving residues from Trp191 to Ile195, as shown by NMR analysis and molecular dynamics simulations. The population of nascent helix was smaller in HcTnI-C27-H than in HcTnI-C27, as shown by circular dichroism (CD) titrations. Fluorescence and isothermal titration calorimetry (ITC) showed that both peptides bound tropomyosin (αTm), with a detectably higher affinity (∼10 μM) of HcTnI-C27 than that of HcTnI-C27-H (∼15 μM), consistent with an impaired Ca2+-desensitization effect of the mutant peptide on skinned muscle strips. Upon binding to αTm, HcTnI-C27 acquired a weakly stable helix-like conformation involving residues near Trp191, as shown by transferred nuclear Overhauser effect spectroscopy and hydrogen/deuterium exchange experiments. With the potent Ca2+-desensitization effect of HcTnI-C27 on skinned cardiac muscle from a mouse model of hypertrophic cardiomyopathy, the data support that the C-terminal end domain of TnI can function as an isolated peptide with the intrinsic capacity of binding tropomyosin, providing a promising therapeutic approach to selectively improve diastolic function of the heart.

Carbazole Derivatives as Kinase-Targeting Inhibitors for Cancer Treatment

Protein Kinases (PKs) are a heterogeneous family of enzymes that modulate several biological pathways, including cell division, cytoskeletal rearrangement, differentiation and apoptosis. In particular, due to their crucial role during human tumorigenesis and cancer progression, PKs are ideal targets for the design and development of effective and low toxic chemotherapeutics and represent the second group of drug targets after G-protein-coupled receptors. Nowadays, several compounds have been claimed to be PKs inhibitors, and some of them, such as imatinib, erlotinib and gefitinib, have already been approved for clinical use, whereas more than 30 others are in various phases of clinical trials. Among them, some natural or synthetic carbazole-based molecules represent promising PKs inhibitors due to their capability to interfere with PK activity by different mechanisms of action including the ability to act as DNA intercalating agents, interfere with the activity of enzymes involved in DNA duplication, such as topoisomerases and telomerases, and inhibit other proteins such as cyclindependent kinases or antagonize estrogen receptors. Thus, carbazoles can be considered a promising this class of compounds to be adopted in targeted therapy of different types of cancer.

Structural stability of SARS-CoV-2 3CLpro and identification of quercetin as an inhibitor by experimental screening

The global health emergency generated by coronavirus disease 2019 (COVID-19) has prompted the search for preventive and therapeutic treatments for its pathogen, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There are many potential targets for drug discovery and development to tackle this disease. One of these targets is the main protease, Mpro or 3CLpro, which is highly conserved among coronaviruses. 3CLpro is an essential player in the viral replication cycle, processing the large viral polyproteins and rendering the individual proteins functional. We report a biophysical characterization of the structural stability and the catalytic activity of 3CLpro from SARS-CoV-2, from which a suitable experimental in vitro molecular screening procedure has been designed. By screening of a small chemical library consisting of about 150 compounds, the natural product quercetin was identified as reasonably potent inhibitor of SARS-CoV-2 3CLpro (Ki ~ 7 μM). Quercetin could be shown to interact with 3CLpro using biophysical techniques and bind to the active site in molecular simulations. Quercetin, with well-known pharmacokinetic and ADMET properties, can be considered as a good candidate for further optimization and development, or repositioned for COVID-19 therapeutic treatment.

Binding of warfarin differently affects the thermal behavior and chain packing of anionic, zwitterionic and cationic lipid membranes

Warfarin is a coumarin derivative drug widely used for its anticoagulant properties. The interaction of warfarin with fully hydrated lipid bilayers has been studied by combining differential scanning calorimetry, spectrophotometry, electron spin resonance of chain-labelled lipids and molecular docking. Bilayers formed by lipids with different chemico-physical properties were considered, namely dimyristoyl-phosphatidylcholine (DMPC), dimyristoyl-phosphatidylglycerol (DMPG), and dioleoyltrimethyl-ammoniumpropane (DOTAP). We observed in all cases the binding of warfarin in proximity of the surface of the bilayers, leading to a variety of distinct effects on key molecular properties of the membranes. The drug associates with the lipid bilayers in the deprotonated open chain form, with an association constant similar for DMPC and DMPG (1.27·10⁴ and 2.82·10⁴ M^-1, respectively) and lower for DOTAP (0.46·10⁴ M^-1). In DMPC bilayers, which are zwitterionic and with saturated symmetrical chains, warfarin at 10 mol% suppresses the pre-transition, slightly stabilizes the fluid state and reduces the cooperativity of the main transition. Moreover, it alters the lateral packing density of the chain segments close to the polar/apolar interface at any temperature through the gel phase. In anionic DMPG bilayers, the drug slightly perturbs the thermotropic phase behavior, and at 10 mol% markedly loosens the compact gel phase packing of the first chain segments. In cationic DOTAP bilayers, possessing unsaturated acyl chains, the drug induces a slightly higher degree of order and motional restriction in the outer hydrocarbon region in the frozen state. In all cases, as a surface adsorbed molecule, warfarin does not affect the segmental chain order and dynamics for temperatures in the fluid phase. The overall results provide an outline of the action of warfarin on membranes formed by lipids of different types.

Molecular docking simulation and in vitro studies on estrogenic activities of flavonoids from leaves of Carya cathayensis Sarg

The main purpose of this study was to evaluate the estrogenic properties of total flavonoids (TFs) and five flavonoid monomers (cardamonin (Car), pinostrobin chalcone (PC), wogonin (Wo), chrysin (Chr) and Pinocembrin (PI)) from leaves of Carya cathayensis Sarg (LCC). TFs from LCC were isolated and determined using HPLC. The 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry were performed to assess the effects of flavonoids on cell proliferation and cell cycle, respectively. The molecular docking technique was applied to investigate binding conformations of the monomers from LCC to the estrogen receptor ERα and ERβ. Gene and protein expression patterns were assessed using quantitative real-time PCR (qRT-PCR) and western blot, respectively. The results showed that TFs, Car, PC, Wo and Chr promoted proliferation of MCF-7 cells and cell transition from the G1 to S phase, and inhabitation of MCF-7 cell proliferation was observed after the treatment of PI. Molecular docking studies confirmed ERs as molecular targets for the monomers. TFs, Car, PC, Wo and Chr from LCC promoted gene expression of ERα, ERβ, progesterone receptor (PR) and pS2. Our collective results demonstrated that TFs and monomers from LCC may exert ER agonist activity through competitively bind to ER, inducing ER upregulation and active ER to estrogen response element (ERE)- independent gene regulation. As an abundant natural product, LCC may provide a novel medicinal source for treatment of diseases caused by estrogen deficiency.

The Paralogue of the Intrinsically Disordered Nuclear Protein 1 Has a Nuclear Localization Sequence that Binds to Human Importin α3

Numerous carrier proteins intervene in protein transport from the cytoplasm to the nucleus in eukaryotic cells. One of those is importin α, with several human isoforms; among them, importin α3 (Impα3) features a particularly high flexibility. The protein NUPR1L is an intrinsically disordered protein (IDP), evolved as a paralogue of nuclear protein 1 (NUPR1), which is involved in chromatin remodeling and DNA repair. It is predicted that NUPR1L has a nuclear localization sequence (NLS) from residues Arg51 to Gln74, in order to allow for nuclear translocation. We studied in this work the ability of intact NUPR1L to bind Impα3 and its depleted species, ∆Impα3, without the importin binding domain (IBB), using fluorescence, isothermal titration calorimetry (ITC), circular dichroism (CD), nuclear magnetic resonance (NMR), and molecular docking techniques. Furthermore, the binding of the peptide matching the isolated NLS region of NUPR1L (NLS-NUPR1L) was also studied using the same methods. Our results show that NUPR1L was bound to Imp α3 with a low micromolar affinity (~5 μM). Furthermore, a similar affinity value was observed for the binding of NLS-NUPR1L. These findings indicate that the NLS region, which was unfolded in isolation in solution, was essentially responsible for the binding of NUPR1L to both importin species. This result was also confirmed by our in silico modeling. The binding reaction of NLS-NUPR1L to ∆Impα3 showed a larger affinity (i.e., lower dissociation constant) compared with that of Impα3, confirming that the IBB could act as an auto-inhibition region of Impα3. Taken together, our findings pinpoint the theoretical predictions of the NLS region in NUPR1L and, more importantly, suggest that this IDP relies on an importin for its nuclear translocation.

Estrogenic Effect of Scoparia dulcis (Linn) Extract in Mice Uterus and In Silico Molecular Docking Studies of Certain Compounds with Human Estrogen Receptors

Background:

Scoparia dulcis Linn. is reported to be used by women of Assam and Arunachal Pradesh in northeast India for treating menstrual disorders. Scoparia dulcis contains compounds that bind with estrogen receptors (ERα and ERβ) evidenced by increased PCNA in endometrial epithelium.

Methods:

Crude extract was orally administered at the dose of 500 mg/kg body weight/day to the female mice (60–70 days old) in five different groups. Each group containing six females included: (I) cyclic control, (II) cyclic extract treated, (III) Ovariectomized (OVX)-vehicle treated (Control), (IV) OVX-E2 treated (V) OVX- extract treated. Extract was administered for eight days to the cyclic groups and three days to the OVX groups. PCNA was detected immunohistochemically in uterine tissues and signals were analyzed by Image J software (NIH, USA). Compounds were separated by GC-MS and identified using NIST. In silico molecular docking studies was performed with human estrogen receptors (ERα and ERβ). Molecular dynamics (MD) simulations of the best interacting compound was done using gromacs.

Results:

The results showed cell proliferation in the uterine endometrium evidenced by PCNA. Two phytocompounds, Octadecanoic acid and methyl stearate showed binding affinity with ERα and ERβ.

Conclusion:

Scoparia dulcis contains compounds having binding affinity with ERα and ERβ. The present study is the first report on compounds from Scoparia dulcis showing binding affinity with human estrogen receptors which may have biological effect on female reproduction.

A Phosphorylation-Induced Switch in the Nuclear Localization Sequence of the Intrinsically Disordered NUPR1 Hampers Binding to Importin

Several carrier proteins are involved in protein transport from the cytoplasm to the nucleus in eukaryotic cells. One of those is importin α, of which there are several human isoforms; among them, importin α3 (Impα3) has a high flexibility. The protein NUPR1, a nuclear protein involved in the cell-stress response and cell cycle regulation, is an intrinsically disordered protein (IDP) that has a nuclear localization sequence (NLS) to allow for nuclear translocation. NUPR1 does localize through the whole cell. In this work, we studied the affinity of the isolated wild-type NLS region (residues 54–74) of NUPR1 towards Impα3 and several mutants of the NLS region by using several biophysical techniques and molecular docking approaches. The NLS region of NUPR1 interacted with Impα3, opening the way to model the nuclear translocation of disordered proteins. All the isolated NLS peptides were disordered. They bound to Impα3 with low micromolar affinity (1.7–27 μM). Binding was hampered by removal of either Lys65 or Lys69 residues, indicating that positive charges were important; furthermore, binding decreased when Thr68 was phosphorylated. The peptide phosphorylated at Thr68, as well as four phospho-mimetic peptides (all containing the Thr68Glu mutation), showed the presence of a sequential NN(i,i + 1) nuclear Overhauser effect (NOE) in the 2D-¹H-NMR (two-dimensional–proton NMR) spectra, indicating the presence of turn-like conformations. Thus, the phosphorylation of Thr68 modulates the binding of NUPR1 to Impα3 by a conformational, entropy-driven switch from a random-coil conformation to a turn-like structure.

Application of Various Molecular Modelling Methods in the Study of Estrogens and Xenoestrogens

In this review, applications of various molecular modelling methods in the study of estrogens and xenoestrogens are summarized. Selected biomolecules that are the most commonly chosen as molecular modelling objects in this field are presented. In most of the reviewed works, ligand docking using solely force field methods was performed, employing various molecular targets involved in metabolism and action of estrogens. Other molecular modelling methods such as molecular dynamics and combined quantum mechanics with molecular mechanics have also been successfully used to predict the properties of estrogens and xenoestrogens. Among published works, a great number also focused on the application of different types of quantitative structure-activity relationship (QSAR) analyses to examine estrogen's structures and activities. Although the interactions between estrogens and xenoestrogens with various proteins are the most commonly studied, other aspects such as penetration of estrogens through lipid bilayers or their ability to adsorb on different materials are also explored using theoretical calculations. Apart from molecular mechanics and statistical methods, quantum mechanics calculations are also employed in the studies of estrogens and xenoestrogens. Their applications include computation of spectroscopic properties, both vibrational and Nuclear Magnetic Resonance (NMR), and also in quantum molecular dynamics simulations and crystal structure prediction. The main aim of this review is to present the great potential and versatility of various molecular modelling methods in the studies on estrogens and xenoestrogens.

Computational Approaches for the Discovery of GPER Targeting Compounds

Estrogens exert a panel of biological activities mainly through the estrogen receptors α and β, which belong to the nuclear receptor superfamily. Diverse studies have shown that the G protein-coupled estrogen receptor 1 (GPER, previously known as GPR30) also mediates the multifaceted effects of estrogens in numerous pathophysiological events, including neurodegenerative, immune, metabolic, and cardiovascular disorders and the progression of different types of cancer. In particular, GPER is implicated in hormone-sensitive tumors, albeit diverse issues remain to be deeply investigated. As such, this receptor may represent an appealing target for therapeutics in different diseases. The yet unavailable complete GPER crystallographic structure, and its relatively low sequence similarity with the other members of the G protein-coupled receptor (GPCR) family, hamper the possibility to discover compounds able to modulate GPER activity. Consequently, a reliable molecular model of this receptor is required for the design of suitable ligands. To date, convergent approaches involving structure-based drug design and virtual ligand screening have led to the identification of several GPER selective ligands, thus providing important information regarding its mode of action and function. In this survey, we summarize results obtained through computer-aided techniques devoted to the assessment of GPER ligands toward their usefulness in innovative treatments of different diseases.

Effect of Gallic acid and Myricetin on ovarian cancer models: a possible alternative antitumoral treatment

Background

Ovarian cancer is the leading cause of mortality among malignant gynecological tumors. Surgical resection and chemotherapy with intravenous platinum/taxanes drugs are the treatments of choice, with little effectiveness in later stages and severe toxicological effects. Therefore, this study aimed to evaluate the antineoplastic activity of gallic acid (GA) and myricetin (Myr) administrated peritumorally in Nu/Nu mice xenotransplanted with SKOV-3 cells.

Methods

Biological activity of GA and MYR was evaluated in SKOV-3 and OVCAR-3 cells (ovarian adenocarcinomas) by confocal/transmission electron microscopy, PI-flow cytometry, H₂-DCF-DA stain, MTT, and Annexin V/PI assays. Molecular targets of compounds were determined with ACD/I-Labs and SEA. Antineoplastic activity was performed in SKOV-3 cells subcutaneously xenotransplanted into female Nu/Nu mice treated peritumorally with 50 mg/kg of each compound (2 alternate days/week) for 28 days. Controls used were paclitaxel (5 mg/kg) and 20 μL of vehicle (0.5% DMSO in 1X PBS). Tumor lesions, organs and sera were evaluated with NMR, USG, histopathological, and paraclinical studies.

Results

In vitro studies showed a decrease of cell viability with GA and Myr in SKOV-3 (50 and 166 μg/mL) and OVCAR-3 (43 and 94 μg/mL) cells respectively, as well as morphological changes, cell cycle arrest, and apoptosis induction due to ROS generation (p ≤ 0.05, ANOVA). In silico studies suggest that GA and MYR could interact with carbonic anhydrase IX and PI3K, respectively. In vivo studies revealed inhibitory effects on tumor lesions development with GA and MYR up to 50% (p ≤ 0.05, ANOVA), with decreased vascularity, necrotic/fibrotic areas, neoplastic stroma retraction and apoptosis. However, toxicological effects were observed with GA treatment, such as leukocyte infiltrate and hepatic parenchyma loss, hypertransaminasemia (ALT: 150.7 ± 25.60 U/L), and hypoazotemia (urea: 33.4 ± 7.4 mg/dL), due to the development of chronic hepatitis (p ≤ 0.05, ANOVA).

Conclusion

GA and Myr (50 mg/kg) administered by peritumoral route, inhibit ovarian tumor lesions development in rodents with some toxicological effects. Additional studies will be necessary to find the appropriate therapeutic dose for GA. Therefore, GA and Myr could be considered as a starting point for the development of novel anticancer agents.

Effects of Polar Head Nature and Tail Length of Single-Chain Lipids on the Conformational Stability of β-Lactoglobulin

Interaction between β-lactoglobulin and single-chain lipids, differing for either the length of the aliphatic chain or the molecular properties of the headgroup, was investigated at neutral and acidic pH to determine the impact on the thermal stability of the protein. Differential scanning calorimetry results with different fatty acids (from C10:0 to C18:0) show a correlation of both melting temperature and unfolding enthalpy of the protein with the ligand binding affinity, and the maximum effect was found for palmitic acid (PLM). The influence of the lipid polar head was investigated by comparing PLM with lyso-palmitoylphosphatidylcholine (LPC), which possesses the same aliphatic chain. At neutral pH, the stabilizing effect of LPC is less favorable compared to PLM. However, fluorescence results revealed that LPC can bind into the protein calyx even at acidic pH, at variance with fatty acids. Molecular dynamics simulations indicated that this difference is due to the ability of the polar head of LPC to interact with the protein loop that regulates the shift (Tanford transition) between open and closed state of the binding site of β-lactoglobulin. The results provide a rationale for how a ligand has the ability to access the protein active site at acidic conditions by overcoming the Tanford transition, and they demonstrate that β-lactoglobulin can deliver ligands with tailored properties of the polar head in a wide pH range.

The Peptide ERα17p Is a GPER Inverse Agonist that Exerts Antiproliferative Effects in Breast Cancer Cells

The inhibition of the G protein-coupled estrogen receptor (GPER) offers promising perspectives for the treatment of breast tumors. A peptide corresponding to part of the hinge region/AF2 domain of the human estrogen receptor α (ERα17p, residues 295–311) exerts anti-proliferative effects in various breast cancer cells including those used as triple negative breast cancer (TNBC) models. As preliminary investigations have evoked a role for the GPER in the mechanism of action of this peptide, we focused our studies on this protein using SkBr3 breast cancer cells, which are ideal for GPER evaluation. ERα17p inhibits cell growth by targeting membrane signaling. Identified as a GPER inverse agonist, it co-localizes with GPER and induces the proteasome-dependent downregulation of GPER. It also decreases the level of pEGFR (phosphorylation of epidermal growth factor receptor), pERK1/2 (phosphorylation of extracellular signal-regulated kinase), and c-fos. ERα17p is rapidly distributed in mice after intra-peritoneal injection and is found primarily in the mammary glands. The N-terminal PLMI motif, which presents analogies with the GPER antagonist PBX1, reproduces the effect of the whole ERα17p. Thus, this motif seems to direct the action of the entire peptide, as highlighted by docking and molecular dynamics studies. Consequently, the tetrapeptide PLMI, which can be claimed as the first peptidic GPER disruptor, could open new avenues for specific GPER modulators.

Determination and analysis of agonist and antagonist potential of naturally occurring flavonoids for estrogen receptor (ERα) by various parameters and molecular modelling approach

Most estrogen receptor α (ERα) ligands target the ligand binding domain (LBD). Agonist 17β-estradiol (E₂) and tamoxifen (TM, known SERM), bind to the same site within the LBD. However, structures of ligand-bound complexes show that E₂ and TM induce different conformations of helix 12 (H12). During the molecular modelling studies of some naturally occurring flavonoids such as quercetin, luteolin, myricetin, kaempferol, naringin, hesperidin, galangin, baicalein and epicatechin with human ERα (3ERT and 1GWR), we observed that most of the ligands bound to the active site pocket of both 3ERT and 1GWR. The docking scores, interaction analyses, and conformation of H12 provided the data to support for the estrogenic or antiestrogenic potential of these flavonoids to a limited degree. Explicit molecular dynamics for 50 ns was performed to identify the stability and compatibility pattern of protein-ligand complex and RMSD were obtained. Baicalein, epicatechin, and kaempferol with 1GWR complex showed similar RMSD trend with minor deviations in the protein backbone RMSD against 1GWR-E₂ complex that provided clear indications that ligands were stable throughout the explicit molecular simulations in the protein and outcome of naringin-3ERT complex had an upward trend but stable throughout the simulations and all molecular dynamics showed stability with less than overall 1 Å deviation throughout the simulations. To examine their estrogenic or antiestrogenic potential, we studied the effect of the flavonoids on viability, progesterone receptor expression and 3xERE/3XERRE-driven reporter gene expression in ERα positive and estrogen responsive MCF-7 breast cancer cells. Epicatechin, myricetin, and kaempferol showed estrogenic potential at 5 µM concentration.

Multi-Residue Method for the Analysis of Stilbene Estrogens in Milk

The rapid analysis of stilbene estrogens is crucially important in the environment, food and health sectors, but quantitation of lower detection limit for stilbene estrogens persists as a severe challenge. We herein described a homologous and sensitive fluorescence polarization (FP) assay based on estrogen receptor α ligand binding domain (ER-LBD) to monitor stilbene estrogens in milk. Under optimal conditions, the half maximal inhibitory concentrations (IC₅₀) of the FP assay were 9.27 nM, 12.94 nM, and 22.38 nM for hexestrol, dienestrol and diethylstilbestrol, respectively. And the corresponding limits of detection (LOD) values were 2.94 nM, 2.89 nM, and 3.12 nM. Finally, the assay was applied to determine the stilbenes in milk samples where the mean recoveries ranged from 95.76% to 112.78% and the coefficients of variation (CV) below 12.00%. Furtherly, we have focused our study on high cross-reactivity phenomena by using two in silico approaches, including molecular docking analysis and topology analysis. Overall, docking results show that several residues in the hydrophobic pocket produce hydrophobic interactions with the tested drug molecules, which contribute to the stability of their binding. In this paper, we conclude that the FP method is suitable for the rapid detection of stilbenes in milk samples, requiring no expensive analytical equipment or time-consuming sample preparation. This work offers a practical approach that applies bioscience technology in food safety testing and improves analytical speed and laboratory efficiency.

Computational biochemical investigation of the binding energy interactions between an estrogen receptor and its agonists

We present the energy profiles of estrogen receptor–agonist ligand interactions in atomic detail using a quantum biochemical approach.