Phorbol esters: structure, biological activity, and toxicity in animals

Protein folding, cellular stress and cancer

Proteins are acknowledged as the phenotypical manifestation of the genotype, because protein-coding genes carry the information for the strings of amino acids that constitute the proteins. It is widely accepted that protein function depends on the corresponding "native" structure or folding achieved within the cell, and that native protein folding corresponds to the lowest free energy minimum for a given protein. However, protein folding within the cell is a non-deterministic dissipative process that from the same input may produce different outcomes, thus conformational heterogeneity of folded proteins is the rule and not the exception. Local changes in the intracellular environment promote variation in protein folding. Hence protein folding requires "supervision" by a host of chaperones and co-chaperones that help their client proteins to achieve the folding that is most stable according to the local environment. Such environmental influence on protein folding is continuously transduced with the help of the cellular stress responses (CSRs) and this may lead to changes in the rules of engagement between proteins, so that the corresponding protein interactome could be modified by the environment leading to an alternative cellular phenotype. This allows for a phenotypic plasticity useful for adapting to sudden and/or transient environmental changes at the cellular level. Starting from this perspective, hereunder we develop the argument that the presence of sustained cellular stress coupled to efficient CSRs may lead to the selection of an aberrant phenotype as the resulting adaptation of the cellular proteome (and the corresponding interactome) to such stressful conditions, and this can be a common epigenetic pathway to cancer.

In vitro toxicity of latex, its terpenoidal fractions and isolated phorbol esters from Euphorbia umbellata (Pax) Bruyns on monocytic and melanoma cells

In Brazil, latex from Euphorbia umbellata (African milk tree) has been increasingly used in folk medicine to treat several types of cancer, including melanoma. The effect of lyophilized latex (LL), its hydroethanolic extract (E80), triterpene (F-TRI)- and diterpene (F-DIT)-enriched fractions, along with six isolated phorbol esters from LL and phorbol 12-myristate 13-acetate (PMA) on J774A.1, THP-1, SK-MEL-28, and B16-F10 cell line viability were evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The compounds were identified by 2D-NMR and HRESIMS. The effect of the LL, extract and fractions on cell viability was also assessed through a resazurin reduction assay. At 100 μg/ml, LL, and its fractions moderately inhibited J774A.1 (37.5-59.5%) and THP-1 (12.6-43.6%) metabolism. LL (IC50 70 μg/ml) and F-TRI (IC50 68 μg/ml) were barely more effective against B16-F10 cells, and only F-TRI exerted an inhibitory effect on SK-MEL-28 cells (IC50 66-75 μg/ml). The samples did not effectively inhibit THP-1 growth (IC50 69-87 μg/ml, assessed by MTT). B16-F10 was susceptible to PMA (IC50 53 μM) and two 12-phenylacetate esters (IC50 56-60 μM), while SK-MEL-28 growth was inhibited (IC50 58 μM) by one of these kinds of esters with an additional 4β-deoxy structure. Synagrantol A (IC50 39 μM) was as effective as PMA (IC50 47 μM) in inhibiting J774A.1 growth in a dose-dependent manner. Furthermore, an in silico study with target receptors indicated a high interaction of the compounds with the PKC proteins. These results provide useful knowledge on the effect of tigliane-type diterpenes on tumor cell from the perspective of medicinal chemistry.

B. Trivella D. NP3 MS Workflow: An Open-Source Software System to Empower Natural Product-Based Drug Discovery Using Untargeted Metabolomics

Natural products (or specialized metabolites) are historically the main source of new drugs. However, the current drug discovery pipelines require miniaturization and speeds that are incompatible with traditional natural product research methods, especially in the early stages of the research. This article introduces the NP3 MS Workflow, a robust open-source software system for liquid chromatography-tandem mass spectrometry (LC-MS/MS) untargeted metabolomic data processing and analysis, designed to rank bioactive natural products directly from complex mixtures of compounds, such as bioactive biota samples. NP3 MS Workflow allows minimal user intervention as well as customization of each step of LC-MS/MS data processing, with diagnostic statistics to allow interpretation and optimization of LC-MS/MS data processing by the user. NP3 MS Workflow adds improved computing of the MS2 spectra in an LC-MS/MS data set and provides tools for automatic [M + H]+ ion deconvolution using fragmentation rules; chemical structural annotation against MS2 databases; and relative quantification of the precursor ions for bioactivity correlation scoring. The software will be presented with case studies and comparisons with equivalent tools currently available. NP3 MS Workflow shows a robust and useful approach to select bioactive natural products from complex mixtures, improving the set of tools available for untargeted metabolomics. It can be easily integrated into natural product-based drug-discovery pipelines and to other fields of research at the interface of chemistry and biology.

Binding of the plant-derived toxin simplexin to bovine protein kinase C: insights from molecular dynamics

Pimelea poisoning of cattle is toxicologically linked to the activation of bovine protein kinase C (PKC) by the plant-derived toxin simplexin. To understand the affinity of PKC for simplexin, we performed molecular dynamics (MD) studies of simplexin, simplexin analogues, and several other activators of PKC. Binding enthalpy calculations indicated that simplexin had the strongest affinity for PKCα-C1B among the activators studied. Key to simplexin's affinity is its ability to form more hydrogen bonds to PKC, compared to the other activators. The C-3 carbonyl group and C-20 hydroxyl group of simplexin were identified as especially important for stabilizing the PKC binding interaction. The hydrophobic alkyl chain of simplexin induces deep membrane embedding of the PKC-simplexin complex, enhancing the protein-ligand hydrogen bonding. Our findings align with previous experiments on structure-activity relationships (SAR) for simplexin analogues, and provide insights that may guide the development of interventions or treatments for Pimelea poisoning.

Untargeted Metabolomic Analysis of Leaves and Roots of Jatropha curcas Genotypes with Contrasting Levels of Phorbol Esters

AIMS

Phorbol esters (PE) are toxic diterpenoids accumulated in physic nut (Jatropha curcas L.) seed tissues. Their biosynthetic pathway remains unknown, and the participation of roots in this process may be possible. Thus, we set out to study the deposition pattern of PE and other terpenoids in roots and leaves of genotypes with detected (DPE) and not detected (NPE) phorbol esters based on previous studies.

OUTLINE OF DATA RESOURCES

We analyzed physic nut leaf and root organic extracts using LC-HRMS. By an untargeted metabolomics approach, it was possible to annotate 496 and 146 metabolites in the positive and negative electrospray ionization modes, respectively.

KEY RESULTS

PE were detected only in samples of the DPE genotype. Remarkably, PE were found in both leaves and roots, making this study the first report of PE in J. curcas roots. Furthermore, untargeted metabolomic analysis revealed that diterpenoids and apocarotenoids are preferentially accumulated in the DPE genotype in comparison with NPE, which may be linked to the divergence between the genotypes concerning PE biosynthesis, since sesquiterpenoids showed greater abundance in the NPE.

UTILITY OF THE RESOURCE

The LC-HRMS files, publicly available in the MassIVE database (identifier MSV000092920), are valuable as they expand our understanding of PE biosynthesis, which can assist in the development of molecular strategies to reduce PE levels in toxic genotypes, making possible the food use of the seedcake, as well as its potential to contain high-quality spectral information about several other metabolites that may possess biological activity.

Breaking the Silence: Regulation of HIV Transcription and Latency on the Road to a Cure

Antiretroviral therapy (ART) has brought the HIV/AIDS epidemic under control, but a curative strategy for viral eradication is still needed. The cessation of ART results in rapid viral rebound from latently infected CD4+ T cells, showing that control of viral replication alone does not fully restore immune function, nor does it eradicate viral reservoirs. With a better understanding of factors and mechanisms that promote viral latency, current approaches are primarily focused on the permanent silencing of latently infected cells ("block and lock") or reactivating HIV-1 gene expression in latently infected cells, in combination with immune restoration strategies to eliminate HIV infected cells from the host ("shock and kill"). In this review, we provide a summary of the current, most promising approaches for HIV-1 cure strategies, including an analysis of both latency-promoting agents (LPA) and latency-reversing agents (LRA) that have shown promise in vitro, ex vivo, and in human clinical trials to reduce the HIV-1 reservoir.

Can a 12-gene expression signature predict the cell transforming potential of tumor promoting agents in Bhas 42 cells?

To date, long-term rodent carcinogenesis assays are the only assays recognized by regulators to assess non-genotoxic carcinogens, but their reliability has been questioned. In vitro cell transformation assays (CTAs) could represent an interesting alternative to animal models as it has the advantage of detecting both genotoxic and non-genotoxic transforming chemicals. Among them, Bhas 42 CTA uses a cell line that has been transfected with the oncogenic sequence v-Ha-ras. This sequence confers an "initiated" status to these cells and makes them particularly sensitive to non-genotoxic agents. In a previous work, transcriptomic analysis revealed that the treatment of Bhas 42 cells with transforming silica (nano)particles and 12-O-tetradecanoylphorbol-13-acetate (TPA) commonly modified the expression of 12 genes involved in cell proliferation and adhesion. In the present study, we assess whether this signature would be the same for four other soluble transforming agents, i.e. mezerein, methylarsonic acid, cholic acid and quercetin. The treatment of Bhas 42 cells for 48 h with mezerein modified the expression of the 12 genes of the signature according to the same profile as that of the TPA. However, methylarsonic acid and cholic acid gave an incomplete signature with changes in the expression of only 7 and 5 genes, respectively. Finally, quercetin treatment induced no change in the expression of all genes but exhibited higher cytotoxicty. These results suggest that among the transforming agents tested, some may share similar mechanisms of action leading to cell transformation while others may activate different additional pathways involved in such cellular process. More transforming and non-transforming agents and gene markers should be tested in order to try to identify a relevant gene signature to predict the transforming potential of non-genotoxic agents.

Exosome Liberation by Human Neutrophils under L-Amino Acid Oxidase of Calloselasma rhodostoma Venom Action

L-Amino acid oxidase (LAAO) is an enzyme found in snake venom that has multifaceted effects, including the generation of hydrogen peroxide (H2O2) during oxidative reactions, leading to various biological and pharmacological outcomes such as apoptosis, cytotoxicity, modulation of platelet aggregation, hemorrhage, and neutrophil activation. Human neutrophils respond to LAAO by enhancing chemotaxis, and phagocytosis, and releasing reactive oxygen species (ROS) and pro-inflammatory mediators. Exosomes cellular nanovesicles play vital roles in intercellular communication, including immune responses. This study investigates the impact of Calloselasma rhodostoma snake venom-derived LAAO (Cr-LAAO) on human neutrophil exosome release, including activation patterns, exosome formation, and content. Neutrophils isolated from healthy donors were stimulated with Cr-LAAO (100 μg/mL) for 3 h, followed by exosome isolation and analysis. Results show that Cr-LAAO induces the release of exosomes with distinct protein content compared to the negative control. Proteomic analysis reveals proteins related to the regulation of immune responses and blood coagulation. This study uncovers Cr-LAAO's ability to activate human neutrophils, leading to exosome release and facilitating intercellular communication, offering insights into potential therapeutic approaches for inflammatory and immunological disorders.

Larvicidal activity of green synthesized iron oxide nanoparticles using Grevillea robusta Cunn. leaf extract against vector mosquitoes and their characterization

Extensive fumigation of synthetic pesticides to control the mosquito vector during each post-monsoon season in Pakistan significantly enhanced the environmental contamination and extinction of beneficial insects from the urban ecosystems. In this context, the present study examined the larvicidal efficacy of green synthesized iron nanoparticles (IONPs), using an aqueous leaf extract of Grevillea robusta against the early 2nd and 4th instar larvae of Aedes aegypti and Anopheles stephensi in Pakistan. The prepared IONPs were characterized by UV-Vis spectrum, FTIR, X-ray diffraction, scanning electron microscopy, and energy-dispersive diffraction. Larvicidal bioassay was conducted at various concentrations (80, 160, 240, 320, and 400 ppm) of IONPs prepared from leaf extract of G. robusta, and readings were taken-every 12 h for two consecutive days. In vitro, larvicidal assay, G. robusta leaf extract IONPs exhibited high mortalities of 64-96% (LC50 = 259.07 ppm; LC90 = 443.92 ppm) for the second instar and 65-98% (LC50 = 238.05 ppm; LC90 = 433.93 ppm) for the fourth instar of Ae. aegypti, while in the case of An. stephensi 56-84% (LC50 = 297.96 ppm; LC90 = 528.69 ppm) for the second and 56-88% (LC50 = 292.72 ppm; LC90 = 514.00 ppm) mortality for fourth larvae at 12-48 h post-exposure times were observed respectively. Significant (p < 0.05) dose-dependent and exposure time-dependent trends were observed among the 2nd and 4th larvalinstar of An. stephensi and Ae. aegypti. However, both species showed similar response and observed no significant (p > 0.05) difference in percentage mortality between the vector mosquitoes An. stephensi and Ae. aegypti. Overall, this study demonstrates that the larvicidal efficacy of green synthesized IONPs at low concentrations can be an ideal eco-friendly and cost-effective biocontrol of vector mosquitoes' larvae of An. stephensi and Ae. aegypti.

Phorbol-12-myristate-13-acetate is a potent enhancer of B cells with a granzyme B+ regulatory phenotype

Introduction

The infusion of ex-vivo-generated regulatory B cells may represent a promising novel therapeutic approach for a variety of autoimmune and hyperinflammatory conditions including graft-versus-host disease.

Methods

Previously, we developed a protocol for the generation of a novel population of regulatory B cells, which are characterized by secretion of enzymatically active granzyme B (GraB cells). This protocol uses recombinant interleukin 21 (IL-21) and goat-derived F(ab)'2 fragments against the human B cell receptor (anti-BCR). Generally, the use of xenogeneic material for the manufacturing of advanced therapy medicinal products should be avoided to prevent adverse immune reactions as well as potential transmission of so far unknown diseases.

Results

In the present work we demonstrated that phorbol-12-myristate-13-acetate (PMA/TPA), a phorbol ester with a particular analogy to the second messenger diacylglycerol (DAG), is a potent enhancer of IL-21-induced differentiation of pre-activated B cells into GraB cells. The percentage of GraB cells after stimulation of pre-activated B cells with IL-21 and PMA/TPA was not significantly lower compared to stimulation with IL-21 and anti-BCR.

Discussion

Given that PMA/TPA has already undergone encouraging clinical testing in patients with certain haematological diseases, our results suggest that PMA/TPA may be a safe and feasible alternative for ex-vivo manufacturing of GraB cells.

Cinnamomum verum extract inhibits NOX2/ROS and PKCδ/JNK/AP-1/NF-κB pathway-mediated inflammatory response in PMA-stimulated THP-1 monocytes

BACKGROUND

Cinnamomum verum J. Presl (Cinnamon) is widely used in the food and pharmaceutical industries. C. verum exhibits various biological activities. However, it is unclear whether C. verum can inhibit NOX, a major source of ROS generation, and exert anti-inflammatory and antioxidant effects in PMA-stimulated THP-1 cells.

PURPOSE

This study investigates the anti-inflammatory and antioxidant effects of C. verum in PMA-stimulated THP-1 cells.

METHODS

The MeOH extract of C. verum was analyzed using UPLC-QTOF/MS. Anti-inflammatory and antioxidant effects of C. verum extract were examined by DCF-DA staining, immunofluorescence staining, RT-PCR, and immunoblotting in PMA-stimulated THP-1 cells.

RESULTS

C. verum and its components, cinnamic acid and coumarin, significantly attenuated the expression of IL-1β, IL-8, CCL5, and COX-2 in PMA-stimulated THP-1. C. verum decreased ROS levels via NOX2 downregulation, as well as ameliorated plasma membrane translocation of PKCδ and decreased JNK phosphorylation. Besides, C. verum suppressed the nuclear translocation of AP-1 and NF-κB, which modulates diverse pro-inflammatory genes.

CONCLUSION

C. verum effectively inhibits inflammation and oxidative stress during monocyte-macrophage differentiation and downregulates inflammatory mediators via NOX2/ROS and PKCδ/JNK/AP-1/NF-κB signaling.

The Cell Transformation Assay: A Historical Assessment of Current Knowledge of Applications in an Integrated Approach to Testing and Assessment for Non-Genotoxic Carcinogens

The history of the development of the cell transformation assays (CTAs) is described, providing an overview of in vitro cell transformation from its origin to the new transcriptomic-based CTAs. Application of this knowledge is utilized to address how the different types of CTAs, variously addressing initiation and promotion, can be included on a mechanistic basis within the integrated approach to testing and assessment (IATA) for non-genotoxic carcinogens. Building upon assay assessments targeting the key events in the IATA, we identify how the different CTA models can appropriately fit, following preceding steps in the IATA. The preceding steps are the prescreening transcriptomic approaches, and assessment within the earlier key events of inflammation, immune disruption, mitotic signaling and cell injury. The CTA models address the later key events of (sustained) proliferation and change in morphology leading to tumor formation. The complementary key biomarkers with respect to the precursor key events and respective CTAs are mapped, providing a structured mechanistic approach to represent the complexity of the (non-genotoxic) carcinogenesis process, and specifically their capacity to identify non-genotoxic carcinogenic chemicals in a human relevant IATA.

Role of Connexin 43 phosphorylation on Serine-368 by PKC in cardiac function and disease

Intercellular communication mediated by gap junction channels and hemichannels composed of Connexin 43 (Cx43) is vital for the propagation of electrical impulses through cardiomyocytes. The carboxyl terminal tail of Cx43 undergoes various post-translational modifications including phosphorylation of its Serine-368 (S368) residue. Protein Kinase C isozymes directly phosphorylate S368 to alter Cx43 function and stability through inducing conformational changes affecting channel permeability or promoting internalization and degradation to reduce intercellular communication between cardiomyocytes. Recent studies have implicated this PKC/Cx43-pS368 circuit in several cardiac-associated diseases. In this review, we describe the molecular and cellular basis of PKC-mediated Cx43 phosphorylation and discuss the implications of Cx43 S368 phosphorylation in the context of various cardiac diseases, such as cardiomyopathy, as well as the therapeutic potential of targeting this pathway.

Influence of Alkali Treatment of Jatropha Curcas L. Filler on the Service Life of Hybrid Adhesive Bonds under Low Cycle Loading

The aim of this research was to evaluate the effect of untreated and 5% aqueous NaOH solution-treated filler of the plant Jatropha Curcas L. on the mechanical properties of adhesive bonds, especially in terms of their service life at different amplitudes of cyclic loading. As a result of the presence of phorbol ester, which is toxic, Jatropha oilseed cake cannot be used as livestock feed. The secondary aim was to find other possibilities for the utilization of natural waste materials. Another use is as a filler in polymer composites, that is, in composite adhesive layers. The cyclic loading of the adhesive bonds was carried out for 1000 cycles in two amplitudes, that is, 5-30% of the maximum force and 5-50% of the maximum force, which was obtained by the static tensile testing of the adhesive bonds with unmodified filler. The static tensile test showed an increase in the shear strength of the adhesive bonds with alkali-treated filler compared to the untreated filler by 3-41%. The cyclic test results did not show a statistically significant effect of the alkaline treatment of the filler surface on the service life of the adhesive bonds. Positive changes in the strain value between adhesive bonds with treated and untreated filler were demonstrated at cyclic stress amplitudes of 5-50%. SEM analysis showed the presence of interlayer defects in the layers of the tested materials, which are related to the oil-based filler used.

Resting time after phorbol 12-myristate 13-acetate in THP-1 derived macrophages provides a non-biased model for the study of NLRP3 inflammasome

Background

The activation of NLRP3 inflammasome in macrophages has been proven to play a crucial role in the development of cardiovascular diseases. THP-1 monocytes can be differentiated to macrophages by incubation with phorbol-12-myristate 13-acetate (PMA), providing a suitable model for in vitro studies. However, PMA has been shown to have effects on the levels of IL-1β, the main mediator of NLRP3 inflammasome, while the effects on the other mediators of the inflammasome have not been reported before.

Methods

THP-1 monocytes were incubated without (THP-1), with 5ng/ml PMA for 48h (PMA48h) or with 5ng/ml PMA for 48h plus 24h in fresh medium (PMArest). Morphological changes and the expression of macrophage surface markers (CD14, CD11b, CD36 and CD204) were evaluated by flow cytometry. Changes in intracellular levels of inflammasome components (NLRP3, ASC, pro-caspase-1, pro-IL1β) were analyzed by western blot and release of mature IL-1β in cell supernatant was analyzed by ELISA. ASC speck formation was determined by immunofluorescence.

Results

After 48h incubation with PMA or subsequent rest in fresh medium, cells became adherent, and the differential expression of CD36, CD11b, CD14 and CD204 compared to THP-1 cells confirmed that PMArest resemble macrophages from a molecular point of view. Changes in the levels were detected in PMA48h group for all the NLRP3-related proteins, with increase of NLRP3 and pro-IL-1β and secretion of mature IL-1β. In PMArest, no pro-IL-1β and lower amounts of mature IL-1β were detected. No ASC speck was found in PMA treated groups, but the addition of a second stimulus to PMArest resulted in ASC speck formation, together with IL-1β production, confirming the responsiveness of the model.

Conclusion

Differentiation of THP-1 with 5ng/ml PMA followed by 24h resting period provides a model that morphologically and molecularly resembles macrophages. However, even at low concentrations, PMA induces production of IL-1β. The 24h rest period provides for down-regulation of pro-IL-1β in PMArest group, without affecting its ability to respond to a second stimulus through activation of inflammasome.

Chemopreventive Effects of Oral Pterostilbene in Multistage Carcinogenesis of Skin Squamous Cell Carcinoma Mouse Model Induced by DMBA/TPA

Skin squamous cell carcinoma (SCC) is a type of non-melanoma skin cancer. Pterostilbene is a natural compound proven to exhibit various pharmacological properties, including chemo-preventive effects. This study aimed to explore the chemo-preventive effect of oral pterostilbene during initiation, promotion or continuous on multistage skin SCC mouse models induced by 7,12-Dimethylbenz(a)anthracene (DMBA)/12-O-Tetradecanoylphorbol-13-acetate (TPA). The experimental design consists of five groups of female Institute of Cancer Research (ICR) mice, with two control groups of vehicle and cancer. Three oral pterostilbene groups consisted of orally administered pterostilbene during initiation, promotion, or continuously. Oral pterostilbene significantly reduced the number and volume of tumours. Oral pterostilbene demonstrated less severe skin histology changes compared to the cancer control group, with less pleomorphic in the cells and nuclei, and the basement membrane remained intact. Our results showed fewer invasive tumours in oral PT-treated groups than in cancer groups that displayed mitotic bodies, highly pleomorphic cells and nuclei, and basement membrane invasion. The cell proliferation marker (Ki-67) was reduced in oral pterostilbene-treated groups. Overall, oral pterostilbene is a promising chemo-preventive intervention due to its anti-initiation and anti-promotion on skin carcinogenesis. Thus, the potential molecular mechanisms of oral pterostilbene chemo-prevention agent should be explored.

Neutrophil Activated by the Famous and Potent PMA (Phorbol Myristate Acetate)

This review will briefly outline the major signaling pathways in PMA-activated neutrophils. PMA is widely used to understand neutrophil pathways and formation of NETs. PMA activates PKC; however, we highlight some isoforms that contribute to specific functions. PKC α, β and δ contribute to ROS production while PKC βII and PKC ζ are involved in cytoskeleton remodeling. Actin polymerization is important for the chemotaxis of neutrophils and its remodeling is connected to ROS balance. We suggest that, although ROS and production of NETs are usually observed together in PMA-activated neutrophils, there might be a regulatory mechanism balancing both. Interestingly, we suggest that serine proteases might determine the PAD4 action. PAD4 could be responsible for the activation of the NF-κB pathway that leads to IL-1β release, triggering the cleavage of gasdermin D by serine proteases such as elastase, leading to pore formation contributing to release of NETs. On the other hand, when serine proteases are inhibited, NETs are formed by citrullination through the PAD4 pathway. This review puts together results from the last 31 years of research on the effects of PMA on the neutrophil and proposes new insights on their interpretation.

Models for cytotoxicity screening of antileishmanial drugs: what has been done so far?

A growing number of studies have demonstrated the in vitro potential of an impressive number of antileishmanial candidates in the past years. However, the lack of uniformity regarding the choice of cell types for cytotoxicity assays may lead to uncomparable and inconclusive data. In vitro assays relying solely on non-phagocytic cell models may not represent a realistic result as the effect of an antileishmanial agent should ideally be presented based on its cytotoxicity profile against reticuloendothelial system cells. In the present review, we have assembled studies published in the scientific literature from 2015 to 2021 that explored leishmanicidal candidates, emphasising the main host cell models used for cytotoxicity assays. The pros and cons of different host cell types as well as primary cells and cell lines are discussed in order to draw attention to the need to establish standardised protocols for preclinical testing when assessing new antileishmanial candidates.

Ethnopharmacological Study of Medicinal Plants Used for the Treatment of Cardiovascular Diseases and Their Associated Risk Factors in sub-Saharan Africa

Cardiovascular diseases (CVDs) are the leading cause of global mortality, including deaths arising from non-communicable diseases in sub-Saharan Africa (SSA). Consequently, this study aimed to provide details of medicinal plants (MPs) employed in SSA for the treatment of CVDs and their related risk factors to open new avenues for the discovery of novel drugs. The extensive ethnopharmacological literature survey of these MPs in 41 SSA countries was based on studies from 1982 to 2021. It revealed 1,085 MPs belonging to 218 botanical families, with Fabaceae (9.61%), Asteraceae (6.77%), Apocynaceae (3.93%), Lamiaceae (3.75%), and Rubiaceae (3.66%) being the most represented. Meanwhile, Allium sativum L., Persea americana Mill., Moringa oleifera Lam., Mangifera indica L., and Allium cepa L. are the five most utilised plant species. The preferred plant parts include the leaves (36%), roots (21%), barks (14%), fruits (7%), and seeds (5%), which are mostly prepared by decoction. Benin, Mauritius, Nigeria, South Africa, and Togo had the highest reported use while most of the investigations were on diabetes and hypertension. Despite the nutraceutical advantages of some of these MPs, their general toxicity potential calls for caution in their human long-term use. Overall, the study established the need for governments of SSA countries to validate the efficacy/safety of these MPs as well as provide affordable, accessible, and improved modern healthcare services.

IL-6 Responsiveness of CD4+ and CD8+ T Cells after Allogeneic Stem Cell Transplantation Differs between Patients and Is Associated with Previous Acute Graft versus Host Disease and Pretransplant Antithymocyte Globulin Therapy

Graft-versus-host disease (GVHD), one of the most common and serious complications after allogeneic stem cell transplantation, is mediated by allocative T cells. IL-6 mediates both pro- and anti-inflammatory effects and modulates T cell response through classical signaling and trans-signaling. We investigated the effects on the mTOR and JAK/STAT pathways after various types of IL-6 signaling for circulating T cells were derived from 31 allotransplant recipients 90 days post-transplant. Cells were stimulated with IL-6 alone, hyper-IL-6 (trans-signaling), IL-6+IL-6 receptor (IL-6R; classical + trans-signaling) and IL-6+IL-6R+soluble gp130-Fc (classical signaling), and flow cytometry was used to investigate the effects on phosphorylation of AKT (Thr308), mTOR (Ser2442), STAT3 (Ser727) and STAT3 (Tyr705). CD3⁺CD4⁺ and CD3⁺C8⁺ T cells responded to classical and trans IL-6 stimulation with increased STAT3 (Tyr705) phosphorylation; these responses were generally stronger for CD3⁺CD4⁺ cells. STAT3 (Tyr705) responses were stronger for patients with previous acute GVHD; CD3⁺CD4⁺ cells from GVHD patients showed an additional STAT3 (Ser727) response, whereas patients without acute GVHD showed additional mTOR (Ser2448) responses. Furthermore, treatment with antithymocyte globulin as a part of GVHD prophylaxis was associated with generally weaker STAT3 (Tyr705) responses and altered STAT3 (Ser727) responsiveness of CD3⁺CD4⁺ cells together with increased mTOR (Ser2448) responses for the CD3⁺CD8⁺ cells. Thus, early post-transplant CD3⁺CD4⁺ and CD3⁺ CD8⁺ T cell subsets differ in their IL-6 responsiveness; this responsiveness is modulated by antithymocyte globulin and differs between patients with and without previous acute GVHD. These observations suggest that allotransplant recipients will be heterogeneous with regard to the effects of post-transplant IL-6 targeting.

Euphocactoside, a New Megastigmane Glycoside from Euphorbia cactus Growing in Saudi Arabia

A phytochemical investigation of the aerial parts of Euphorbia cactus Ehrenb. ex Boiss. revealed a new megastigmane, euphocactoside (5), along with eleven known metabolites. Euphocactoside (5) is the 3-O-glucoside derivative of a polyhydroxylated megastigmane showing unprecedented structural features. The structure of euphocactoside, including stereochemical details, was elucidated by extensive spectroscopic analysis based on 1D and 2D nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HR-ESIMS). The isolated compounds were evaluated for their cytotoxic activity against three different human cancer cell lines, namely, A549 (lung), LoVo (colon), and MCF-7 (breast), using MTT assay, and moderate to marginal activities were observed for compounds 1–3, 8 and 9 against all three cell lines.

Safety of hydrothermally treated kernels from edible Jatropha curcas L. (Chuta) as a novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on hydrothermally treated kernels from edible Jatropha curcas (Chuta) as a novel food (NF) pursuant to Regulation (EU) 2015/2283. Although Jatropha curcas is generally considered a toxic plant due to the presence of phorbol esters (PEs), edible varieties exist in Central America. The applicant has developed a breeding programme for an edible cultivar and proposes the kernels from this cultivar as an NF as whole kernels or fragments thereof to be used as a snack or as a food ingredient. Procedures are in place to avoid commingling with non-edible kernels, with the last steps being the analytical control of PEs concentrations in all produced batches. The Panel considers that the production process of the NF is sufficiently described and that the information provided on the composition of the NF is sufficient for its characterisation. Components of the NF were tested for genotoxicity applying the standard in vitro test battery and no genotoxic concerns have been identified. In a conservative scenario for exposure to PEs from the NF, it was assumed that all kernels contain PEs at the level of detection of the analytical method. When comparing the estimated maximum exposure to PEs with a reference point from a subchronic study in pigs, a margin of exposure ≥ 900 is obtained, which is considered sufficiently large. The presence of anti-nutritional factors does not pose safety concerns as they are within the ranges found in vegetables. The Panel concludes that the NF is safe under the proposed conditions of use.

Molecular dynamics simulation studies on binding of activator and inhibitor to Munc13-1 C1 in the presence of membrane

Munc13-1 is a presynaptic active zone protein that plays a critical role in priming the synaptic vesicle and releasing neurotransmitters in the brain. Munc13-1 acts as a scaffold and is activated when diacylglycerol (DAG)/phorbol ester binds to its C1 domain in the plasma membrane. Our previous studies showed that bryostatin 1 activated the Munc13-1, but resveratrol inhibited the phorbol ester-induced Munc13-1 activity. To gain structural insights into the binding of the ligand into Munc13-1 C1 in the membrane, we conducted 1.0 μs molecular dynamics (MD) simulation on Munc13-1 C1-ligand-lipid ternary system using phorbol 13-acetate, bryostatin 1 and resveratrol as ligands. Munc13-1 C1 shows higher conformational stability and less mobility along membrane with phorbol 13-acetate and bryostatin 1 than with resveratrol. Bryostatin 1 and phorbol ester remained in the protein active site, but resveratrol moved out of Munc13-1 C1 during the MD simulation. While bryostatin 1-bound Munc13-1 C1 showed two different positioning in the membrane, phorbol 13-acetate and resveratrol-bound Munc13-1 C1 only showed one positioning. Phorbol 13-acetate formed hydrogen bond with Ala-574 and Gly-589. Bryostatin 1 had more hydrogen bonds with Trp-588 and Arg-592 than with other residues. Resveratrol formed hydrogen bond with Ile-590. This study suggests that different ligands control Munc13-1 C1's mobility and positioning in the membrane differently. Ligand also has a critical role in the interaction between Munc13-1 C1 and lipid membrane. Our results provide structural basis of the pharmacological activity of the ligands and highlight the importance of membrane in Munc13-1 activity.Communicated by Ramaswamy H. Sarma.

New phorbol ester derivatives as potent anti-HIV agents

Tigliane esters show many biological activities, including anti-HIV-1 activity. Our aim in this study was to establish structure-anti-HIV activity relationships for four series of tigliane-type diterpenoids. We synthesized and evaluated 29 new phorbol ester derivatives for anti-HIV activity and for cytotoxicity against human tumor cell lines. Among them, three derivatives, two phorbol-13-monoesters (5d and 5e) and a phorbol-12,13-diester (6a), showed significant anti-HIV activity. We found that better anti-HIV activity was often associated with a shorter acyl ester at C-13. Particularly, compounds with a phenyl ring in the ester side chain exhibited excellent anti-HIV activity and had good safety indexes. Due to its significant anti-HIV potency with a high selectivity index, phorbol-12,13-dicinnamoate (6a) was chosen as the potential candidate for further preclinical trials.

Targeting Drug Chemo-Resistance in Cancer Using Natural Products

Cancer is one of the leading causes of death globally. The development of drug resistance is the main contributor to cancer-related mortality. Cancer cells exploit multiple mechanisms to reduce the therapeutic effects of anticancer drugs, thereby causing chemotherapy failure. Natural products are accessible, inexpensive, and less toxic sources of chemotherapeutic agents. Additionally, they have multiple mechanisms of action to inhibit various targets involved in the development of drug resistance. In this review, we have summarized the basic research and clinical applications of natural products as possible inhibitors for drug resistance in cancer. The molecular targets and the mechanisms of action of each natural product are also explained. Diverse drug resistance biomarkers were sensitive to natural products. P-glycoprotein and breast cancer resistance protein can be targeted by a large number of natural products. On the other hand, protein kinase C and topoisomerases were less sensitive to most of the studied natural products. The studies discussed in this review will provide a solid ground for scientists to explore the possible use of natural products in combination anticancer therapies to overcome drug resistance by targeting multiple drug resistance mechanisms.

Codiaeum variegatum (L.) Rumph. ex A. Juss. (Euphorbiaceae): An overview of its botanical diversity, traditional uses, phytochemistry, pharmacological effects and perspectives towards developing its plant-based products

ETHNOPHARMACOLOGICAL RELEVANCE

Codiaeum variegatum also called miracle shrub, is a plant species constituted of more than 300 cultivars which are mostly used as indoor plants for decoration. However, some of these varieties are used by indigenous populations for the treatment of diarrhoea, stomach ache, external wounds, intestinal worms and ulcers.

AIM OF THE STUDY

This study describes an overview of the botanical diversity, medicinal uses, phytochemical composition of C. variegatum. Then it critically discusses its pharmacological activities versus toxic potential and new perspectives are suggested for the development of its plant-based products.

MATERIALS AND METHODS

A bibliographic assessment of publications on C. variegatum indexed in Google Scholar, PubMed, Science Direct, Scopus, Springer Link, and Web of Science online databases was conducted from 1970 to 2020, and 89 relevant articles related to the botanical diversity (17), traditional uses (22), phytochemical analysis (11), pharmacological activity (31) and toxicity profile (18) of C. variegatum were selected for this review.

RESULTS

Most commonly, it was found that aqueous leaf extracts or decoctions of C. variegatum are used in traditional medicine to treat amoebic dysentery and stomach ache while a bath with root decoction or sap is applied in small quantities on skin related infections. A total of 14 identified and 24 non-identified varieties of C. variegatum were reported for pharmacological activity, and prominent research topics include the anti-amoebic, antimicrobial, antiviral and cytotoxic activities. Alkaloids (3), terpenoids (5) and phenolics (15) were the major compounds identified, and a new antiviral cyanoglucoside was isolated from the sap of C. variegatum. Toxic substances (5-deoxyingenol and phorbol esters) were found in some varieties used as ornamental plants, but the Mollucanum variety used in traditional medicine was found to be safe.

CONCLUSION

The present review revealed that the native variety of C. variegatum (cv. Mollucanum) can be used to treat amoebic dysentery. Alkaloids, terpenoids and phenolic compounds have been characterized in this plant species while other classes of phytochemicals are not yet investigated. The development of new cultivars recommends an in-depth toxicological study before any use. No clinical trial has been reported to date, and further studies are needed to evaluate other claimed medicinal uses. Due to its efficacy and safety, the Mollucanum variety is most likely suitable for the development of a medicine against amoebiasis, which will surely lay the foundation for clinical studies.

Benefits and Challenges of Jatropha Meal as Novel Biofeed for Animal Production

Jatropha curcas L. has gained importance as a source of seed oil for biodiesel production. The meal contained about 60% protein with a good balance of essential amino acids, containing various bioactive compounds, including saponins, phytic acids, trypsin inhibitors, lectins, phenolics, and flavonoids, which render it as a potential biofeed for animal production. The Jatropha meal demonstrated various biological activities, including antioxidant, antibacterial, and anti-inflammatory effects which enhance its property as a bio-feed. The levels of these bioactive compounds in the seeds are dependent on the genotypes. The J. curcas possessed different varieties which are either toxic or non-toxic according to the presence of phorbol esters. The presence of phorbol esters in the meal confirmed the toxic variety of Jatropha resulting in the limited application of meal as a biofeed. The Jatropha meal devoid of phorbol esters could be applied as a biofeed in the animal production industry, and for the toxic varieties, various techniques such as physicochemical and biological treatments have been introduced to the industry to remove the phorbol esters from Jatropha meal. Several studies employing various cells and animals confirmed the toxicity of the phorbol esters. The molecular mechanism of action of phorbol esters is through up-regulation of PKC-β II gene, overexpression of down-stream proto-oncogenes resulted in inflammation and oxidative stress ending by apoptotic cell death. Despite the presence of valuable bioactive compounds in the Jatropha meal, its nutritional application is not recommended unless the phorbol esters are completely removed.

Euphorbia Diterpenes: An Update of Isolation, Structure, Pharmacological Activities and Structure-Activity Relationship

Euphorbia species have a rich history of ethnomedicinal use and ethnopharmacological applications in drug discovery. This is due to the presence of a wide range of diterpenes exhibiting great structural diversity and pharmacological activities. As a result, Euphorbia diterpenes have remained the focus of drug discovery investigations from natural products. The current review documents over 350 diterpenes, isolated from Euphorbia species, their structures, classification, biosynthetic pathways, and their structure-activity relationships for the period covering 2013-2020. Among the isolated diterpenes, over 20 skeletal structures were identified. Lathyrane, jatrophane, ingenane, ingenol, and ingol were identified as the major diterpenes in most Euphorbia species. Most of the isolated diterpenes were evaluated for their cytotoxicity activities, multidrug resistance abilities, and inhibitory activities in vitro, and reported good activities with significant half-inhibitory concentration (IC50) values ranging from 10-50 µM. The lathyranes, isopimaranes, and jatrophanes diterpenes were further found to show potent inhibition of P-glycoprotein, which is known to confer drug resistance abilities in cells leading to decreased cytotoxic effects. Structure-activity relationship (SAR) studies revealed the significance of a free hydroxyl group at position C-3 in enhancing the anticancer and anti-inflammatory activities and the negative effect it has in position C-2. Esterification of this functionality, in selected diterpenes, was found to enhance these activities. Thus, Euphorbia diterpenes offer a valuable source of lead compounds that could be investigated further as potential candidates for drug discovery.

A holistic approach to soil contamination and sustainable phytoremediation with energy crops in the Aegean Region of Turkey

The objective of this current review article is to evaluate the current knowledge of the contaminated soil in the study area based on reports and the results of previous experimental studies in the literature and to discuss the feasibility of phytoremediation with biofuel production using energy crops. The results indicated that the soil contamination was related mainly to the thermal power plant and mining activities in Kütahya, high industrial activity in İzmir, heavy metal and radioactive pollution in Manisa and Muğla. Moreover, the sources of the contamination are geothermal resources and transportation in Aydın and Denizli, respectively. However, soil pollution in Afyonkarahisar and Uşak provinces has not been discussed due to a lack of detailed reports and data in the literature. Besides, energy crops such as Zea mays, Ricinus communis, and Gossypium hirsitum were identified as appropriate candidates for İzmir, Denizli, Manisa, and Aydın due to being resistant to the arid climate. In Muğla province, Eucalyptus grandis and Eucalyptus bicostata can be cultivated because of having adaptation to moderate climatic conditions. Ricinus communis and Helianthus annuus were determined to be very suitable energy crops for the phytoremediation of many heavy metals in Kütahya. The review promotes the development of economic, environmental, and social benefits to regain the contaminated areas through phytoremediation. The findings of the study are important for creating sustainable solutions for remediation of polluted soils in Turkey, as well as for shedding light on the process of establishing appropriate policies to make soils contaminated suitable for agriculture.

The Antimicrobial and Anti-Inflammatory Effects of Silver Nanoparticles Synthesised from Cotyledon orbiculata Aqueous Extract

Cotyledon orbiculata, commonly known as pig’s ear, is an important medicinal plant of South Africa. It is used in traditional medicine to treat many ailments, including skin eruptions, abscesses, inflammation, boils and acne. Many plants have been used to synthesize metallic nanoparticles, particularly silver nanoparticles (AgNPs). However, the synthesis of AgNPs from C. orbiculata has never been reported before. The aim of this study was to synthesize AgNPs using C. orbiculata and evaluate their antimicrobial and immunomodulatory properties. AgNPs were synthesized and characterized using Ultraviolet-Visible Spectroscopy (UV-Vis), Dynamic Light Scattering (DLS) and High-Resolution Transmission Electron Microscopy (HR-TEM). The antimicrobial activities of the nanoparticles against skin pathogens (Staphylococcus aureus, Staphylococcus epidermidis, Methicillin Resistance Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans) as well as their effects on cytokine production in macrophages (differentiated from THP-1 cells) were evaluated. The AgNPs from C. orbiculata exhibited antimicrobial activity, with the highest activity observed against P. aeruginosa (5 µg/mL). The AgNPs also showed anti-inflammatory activity by inhibiting the secretion of pro-inflammatory cytokines (TNF-alpha, IL-6 and IL-1 beta) in lipopolysaccharide-treated macrophages. This concludes that the AgNPs produced from C. orbiculata possess antimicrobial and anti-inflammation properties.

The small-molecule protein ligand interface stabiliser E7820 induces differential cell line specific responses of integrin α2 expression

BACKGROUND

The mechanism of small-molecule stabilised protein-protein interactions is of growing interest in the pharmacological discovery process. A plethora of different substances including the aromatic sulphonamide E7820 have been identified to act by such a mechanism. The process of E7820 induced CAPERα degradation and the resultant transcriptional down regulation of integrin α2 expression has previously been described for a variety of different cell lines and been made responsible for E7820's antiangiogenic activity. Currently the application of E7820 in the treatment of various malignancies including pancreas carcinoma and breast cancer is being investigated in pre-clinical and clinical trials. It has been shown, that integrin α2 deficiency has beneficial effects on bone homeostasis in mice. To transfer E7820 treatment to bone-related pathologies, as non-healing fractures, osteoporosis and bone cancer might therefore be beneficial. However, at present no data is available on the effect of E7820 on osseous cells or skeletal malignancies.

METHODS

Pre-osteoblastic (MC3T3 and Saos-2) cells and endothelial (eEnd2 cells and HUVECs) cells, each of human and murine origin respectively, were investigated. Vitality assay with different concentrations of E7820 were performed. All consecutive experiments were done at a final concentration of 50 ng/ml E7820. The expression and production of integrin α2 and CAPERα were investigated by quantitative real-time PCR and western blotting. Expression of CAPERα splice forms was differentiated by semi-quantitiative reverse transcriptase PCR.

RESULTS

Here we present the first data showing that E7820 can increase integrin α2 expression in the pre-osteoblast MC3T3 cell line whilst also reproducing canonical E7820 activity in HUVECs. We show that the aberrant activity of E7820 in MC3T3 cells is likely due to differential activity of CAPERα at the integrin α2 promoter, rather than due to differential CAPERα degradation or differential expression of CAPERα spliceforms.

CONCLUSION

The results presented here indicate that E7820 may not be suitable to treat certain malignancies of musculoskeletal origin, due to the increase in integrin α2 expression it may induce. Further investigation of the differential functioning of CAPERα and the integrin α2 promoter in cells of various origin would however be necessary to more clearly differentiate between cell lines that will positively respond to E7820 from those that will not.

Clinical Efficacy of Cortex Daphnes (Zushima) Patch in Patients With Symptomatic Knee Osteoarthritis: A Multicenter Non-Inferiority Randomized Controlled Clinical Trial

Background: Osteoarthritis (OA) is imposing substantial burdens on individuals and society with the aging population. Cortex Daphnes patch is widely used for symptomatic knee OA in China with a satisfying clinical efficacy; however, there is scant clinical evidence supporting its use. To evaluate its efficacy, we conducted a multicenter, non-inferiority, randomized, parallel-group study comparing Cortex Daphnes patch with topical nonsteroidal anti-inflammatory drugs in patients with knee OA (NCT02770950).

Methods: A total of 264 symptomatic knee OA patients were treated with Cortex Daphnes or indomethacin cataplasms applied to affected sites once daily for 2 weeks. The primary outcome was improvement in knee pain on walking as assessed using a visual analog scale (VAS). The non-inferiority margin based on the full analysis population was set as –5 mm on the pain VAS. The secondary outcomes were changes of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score, WOMAC scores for pain, function and stiffness, the 36-item Short Form Health Survey (SF-36), and global assessment of knees by the patients. Responder rates for pain VAS, WOMAC total score, and WOMAC pain were also included in the secondary outcomes.

Results: The Cortex Daphnes patch was non-inferior to indomethacin cataplasms for the primary outcome with a group difference (Cortex Daphnes patch–indomethacin cataplasm) of 2.1 mm (95% confidence interval: 2.1–6.4); similar results were found in the per-protocol population. For all other outcomes, no significant differences were found in the full analysis set or in the per-protocol analysis set, except the responder rates for WOMAC pain was higher in the Cortex Daphnes patch group than in the indomethacin cataplasm group (78.4 vs. 64.7%, p = 0.022) in the per-protocol analysis set. Overall, 28.8% patients in the Cortex Daphnes patch group and 9.8% in the indomethacin cataplasm group reported treatment-related adverse events, the vast majority of which were mild-to-moderate skin irritation, resulting in only 3.8 and 0.8% of patients dropping out, respectively.

Conclusion: The Cortex Daphnes patch, which provides satisfactory analgesic efficacy and enhances the physical function of the knee, as well as improving quality of life, may be a promising alternative to knee OA.

Flavonoids from the Genus Euphorbia: Isolation, Structure, Pharmacological Activities and Structure-Activity Relationships

Plants of the genus Euphorbia are widely distributed across temperate, tropical and subtropical regions of South America, Asia and Africa with established Ayurvedic, Chinese and Malay ethnomedical records. The present review reports the isolation, occurrence, phytochemistry, biological properties, therapeutic potential and structure-activity relationship of Euphorbia flavonoids for the period covering 2000-2020, while identifying potential areas for future studies aimed at development of new therapeutic agents from these plants. The findings suggest that the extracts and isolated flavonoids possess anticancer, antiproliferative, antimalarial, antibacterial, anti-venom, anti-inflammatory, anti-hepatitis and antioxidant properties and have different mechanisms of action against cancer cells. Of the investigated species, over 80 different types of flavonoids have been isolated to date. Most of the isolated flavonoids were flavonols and comprised simple O-substitution patterns, C-methylation and prenylation. Others had a glycoside, glycosidic linkages and a carbohydrate attached at either C-3 or C-7, and were designated as d-glucose, l-rhamnose or glucorhamnose. The structure-activity relationship studies showed that methylation of the hydroxyl groups on C-3 or C-7 reduces the activities while glycosylation loses the activity and that the parent skeletal structure is essential in retaining the activity. These constituents can therefore offer potential alternative scaffolds towards development of new Euphorbia-based therapeutic agents.

Multicomponent synthesis and preliminary anti-inflammatory activity of lipophilic diphenylamines

Non-Steroidal Anti-inflammatory Drugs (NSAIDs) are some of the most prescribed medications for pain but the incidence of adverse effects -especially during chronic treatment- points out the requirement of new analgesics. In this study, we showed an efficient two-steps synthesis of diphenylamine-containing dipeptides consisting of a multicomponent process followed by a Buchwald-Hartwig cross-coupling reaction. We prepared 16 diphenylamine derivatives and evaluated their in vivo anti-inflammatory activity through an ear edema model using 12-O-tetradecanoylpholbol-13-acetate. Furthermore, the toxicity of the more potent compounds in the Artemia salina model and their cell viability using murine RAW 264.7 cells is reported. The fluorinated compound 10k becomes a reliable candidate since it reduced the TPA-induced edema to 92%, lacked cytotoxicity against murine macrophages, and had minimal toxicity in Artemia salina.

Thapsigargin-Stimulated LAD2 Human Mast Cell Line Is a Potent Cellular Adjuvant for the Maturation of Monocyte-Derived Dendritic Cells for Adoptive Cellular Immunotherapy

The preparation of dendritic cells (DCs) for adoptive cellular immunotherapy (ACI) requires the maturation of ex vivo-produced immature(i) DCs. This maturation ensures that the antigen presentation triggers an immune response towards the antigen-expressing cells. Although there is a large number of maturation agents capable of inducing strong DC maturation, there is still only a very limited number of these agents approved for use in the production of DCs for ACI. In seeking novel DC maturation agents, we used differentially activated human mast cell (MC) line LAD2 as a cellular adjuvant to elicit or modulate the maturation of ex vivo-produced monocyte-derived iDCs. We found that co-culture of iDCs with differentially activated LAD2 MCs in serum-containing media significantly modulated polyinosinic:polycytidylic acid (poly I:C)-elicited DC maturation as determined through the surface expression of the maturation markers CD80, CD83, CD86, and human leukocyte antigen(HLA)-DR. Once iDCs were generated in serum-free conditions, they became refractory to the maturation with poly I:C, and the LAD2 MC modulatory potential was minimized. However, the maturation-refractory phenotype of the serum-free generated iDCs was largely overcome by co-culture with thapsigargin-stimulated LAD2 MCs. Our data suggest that differentially stimulated mast cells could be novel and highly potent cellular adjuvants for the maturation of DCs for ACI.

Ubash3b promotes TPA-mediated suppression of leukemogenesis through accelerated downregulation of PKCδ protein

Acquired drug-resistance, often involving downregulation or mutations in the target protein, is a major caveat in precision medicine. Understanding mechanisms of resistance to therapeutic drugs may unravel strategies to overcome or prevent them. We previously identified phorbol ester (PE) compounds such as TPA that induce Protein Kinase δ (PKCδ), thereby suppressing leukemogenesis. Here we identified erythroleukemia cell lines that resist PEs and showed that reduced PKCδ protein expression underlies drug resistance. Reduced level of PKCδ in resistant cell lines was due to its phosphorylation followed by protein degradation. Indeed, proteasome inhibition prevented PE-induced loss of PKCδ. Accordingly, a combination of TPA and the proteasome inhibitor ALLN significantly suppressed leukemia in a mouse model of leukemia. PKCδ downregulation by TPA was independent of the downstream MAPK/ERK/P38/JNK pathway. Instead, expression of ubiquitin-associated and SH3 domain-containing protein b (Ubash3b) was induced by TPA, which leads to PKCδ protein dephosphorylation and degradation. This specific degradation was blocked by RNAi-mediated depletion of Ubash3b. In drug-sensitive leukemic cells, TPA did not induce Ubash3b, and consequently, PKCδ levels remained high. A PE-resistant cell line derived from PE-treated sensitive cells exhibited very low PKCδ expression. In these drug resistance cells, a Ubash3b independent mechanism led to PKCδ degradation. Thus, PE compounds in combination with proteasome or specific inhibitors for Ubash3b, or other factors can overcome resistance to TPA, leading to durable suppression of leukemic growth. These results identify Ubash3b as a potential target for drug development.

Molecular genomic features associated with in vitro response of the NCI-60 cancer cell line panel to natural products

Natural products remain a significant source of anticancer chemotherapeutics. The search for targeted drugs for cancer treatment includes consideration of natural products, which may provide new opportunities for antitumor cytotoxicity as single agents or in combination therapy. We examined the association of molecular genomic features in the well-characterized NCI-60 cancer cell line panel with in vitro response to treatment with 1302 small molecules which included natural products, semisynthetic natural product derivatives, and synthetic compounds based on a natural product pharmacophore from the Developmental Therapeutics Program of the US National Cancer Institute's database. These compounds were obtained from a variety of plant, marine, and microbial species. Molecular information utilized for the analysis included expression measures for 23059 annotated transcripts, lncRNAs, and miRNAs, and data on protein-changing single nucleotide variants in 211 cancer-related genes. We found associations of expression of multiple genes including SLFN11, CYP2J2, EPHX1, GPC1, ELF3, and MGMT involved in DNA damage repair, NOTCH family members, ABC and SLC transporters, and both mutations in tyrosine kinases and BRAF V600E with NCI-60 responses to specific categories of natural products. Hierarchical clustering identified groups of natural products, which correlated with a specific mechanism of action. Specifically, several natural product clusters were associated with SLFN11 gene expression, suggesting that potential action of these compounds may involve DNA damage. The associations between gene expression or genome alterations of functionally relevant genes with the response of cancer cells to natural products provide new information about potential mechanisms of action of these identified clusters of compounds with potentially similar biological effects. This information will assist in future drug discovery and in design of new targeted cancer chemotherapy agents.

Current and Promising Antivirals Against Chikungunya Virus

Chikungunya virus (CHIKV) is the causative agent of chikungunya fever (CHIKF) and is categorized as a(n) (re)emerging arbovirus. CHIKV has repeatedly been responsible for outbreaks that caused serious economic and public health problems in the affected countries. To date, no vaccine or specific antiviral therapies are available. This review gives a summary on current antivirals that have been investigated as potential therapeutics against CHIKF. The mode of action as well as possible compound targets (viral and host targets) are being addressed. This review hopes to provide critical information on the in vitro efficacies of various compounds and might help researchers in their considerations for future experiments.

Mobitz Type II Atrioventricular Heart Block After Candlenut Ingestion

The candlenut is a highly accessible seed marketed as a natural weight-loss supplement. However, there is little known about the exact mechanism of action for weight loss nor for the many adverse symptoms it causes, such as nausea, vomiting, fatigue, cardiac dysrhythmias, and even death. In this case report, the authors present a 44-year-old woman who developed a second-degree, Mobitz type II atrioventricular block after consumption of a candlenut supplement. She presented to the emergency department with syncope and her cardiac rhythm indicated a second-degree heart block soon after ingesting candlenuts recommended by her treating physician. Interestingly, a detectable digoxin concentration obtained on hospital day 2 was measured but of unclear significance given no obvious exposure to a cardioactive glycoside. The patient's rhythm normalized on hospital day 2 and she was discharged uneventfully.

Pivotal role of DPYSL2A in KLF4-mediated monocytic differentiation of acute myeloid leukemia cells

Although the biological importance of Krüppel-like factor 4 (KLF4) transcription factor in the terminal differentiation of hematopoietic cells to the monocytes has been well established, the underlying mechanisms remain elusive. To clarify the molecular basis of KLF4-mediated monocytic differentiation, we performed detailed genetic studies in acute myeloid leukemia (AML) cells. Here, we report that dihydropyrimidinase like 2 (DPYSL2), also known as CRMP2, is a novel key differentiation mediator downstream of KLF4 in AML cells. Interestingly, we discovered that KLF4-mediated monocytic differentiation is selectively dependent on one specific isoform, DPYSL2A, but not on other DPYSL family genes. Terminal differentiation to the monocytes and proliferation arrest in AML cells induced by genetic or pharmacological upregulation of KLF4 were significantly reversed by short hairpin RNA (shRNA)-mediated selective depletion of DPYSL2A. Chromatin immunoprecipitation assay revealed that KLF4 associates with the proximal gene promoter of DPYSL2A and directly transactivates its expression. Together with the unique expression patterns of KLF4 and DPYSL2 limited to the differentiated monocytes in the hematopoietic system both in human and mouse, the identified KLF4-DPYSL2 axis in leukemia cells may serve as a potential therapeutic target for the development of novel differentiation therapies for patients with AML.

Toxin Degradation by Rumen Microorganisms: A Review

Animal feeds may contain exogenous compounds that can induce toxicity when ruminants ingest them. These toxins are secondary metabolites originating from various sources including plants, bacteria, algae and fungi. Animal feed toxins are responsible for various animal poisonings which negatively impact the livestock industry. Poisoning is more frequently reported in newly exposed, naïve ruminants while ‘experienced’ ruminants are observed to better tolerate toxin-contaminated feed. Ruminants can possess detoxification ability through rumen microorganisms with the rumen microbiome able to adapt to utilise toxic secondary metabolites. The ability of rumen microorganisms to metabolise these toxins has been used as a basis for the development of preventative probiotics to confer resistance against the poisoning to naïve ruminants. In this review, detoxification of various toxins, which include plant toxins, cyanobacteria toxins and plant-associated fungal mycotoxins, by rumen microorganisms is discussed. The review will include clinical studies of the animal poisoning caused by these toxins, the toxin mechanism of action, toxin degradation by rumen microorganisms, reported and hypothesised detoxification mechanisms and identified toxin metabolites with their toxicity compared to their parent toxin. This review highlights the commercial potential of rumen inoculum derived probiotics as viable means of improving ruminant health and production.

12-O-Tetradecanoylphorbol-13-acetate increases cardiomyogenesis through PKC/ERK signaling

12-O-Tetradecanoylphorbol-13-acetate (TPA) is the most widely used diacylglycerol (DAG) mimetic agent and inducer of protein kinase C (PKC)-mediated cellular response in biomedical studies. TPA has been proposed as a pluripotent cell differentiation factor, but results obtained have been inconsistent. In the present study we show that TPA can be applied as a cardiomyogenesis-promoting factor for the differentiation of mouse embryonic stem (mES) cells in vitro. The mechanism of TPA action is mediated by the induction of extracellular signal-regulated kinase (ERK) activity and the subsequent phosphorylation of GATA4 transcription factor. Interestingly, general mitogens (FGF, EGF, VEGF and serum) or canonical WNT signalling did not mimic the effect of TPA. Moreover, on the basis of our results, we postulate that a TPA-sensitive population of cardiac progenitor cells exists at a certain time point (after days 6–8 of the differentiation protocol) and that the proposed treatment can be used to increase the multiplication of ES cell-derived cardiomyocytes.

Enriched Terpenes Fractions of the Latex of Euphorbia umbellata Promote Apoptosis in Leukemic Cells

The current study was carried out by a bioguided fractionation of a hexane extract of the latex of Euphorbia umbellata against leukemic cells. Samples were analyzed by NMR, GC/MS, triterpenes quantification, and MTT reduction assay. Morphological, cell cycle, mitochondrial membrane potential and caspases 3/7 analyses were performed for the dichloromethane and ethanol fractions, and selectivity index for the dichloromethane fraction. NMR analysis presented characteristic signals of terpenes and steroids, data were confirmed by the quantification of triterpenes and GC/MS analysis. MTT reduction assay demonstrated that HL-60 was the most sensitive cell lineage against dichloromethane and ethanol fractions. Compounds of these matrices caused morphological changes compatible with apoptosis induction, altered cell cycle, increment of depolarized population cells and activation of caspases 3/7. Selectivity indices were higher than 22.44. Bioguided-fractionation study showed that samples of the latex of E. umbellata raised the activity of the phytocomplex against leukemic cells, and the cytotoxicity can be associated with an apoptosis pathway.

Targeting gap junctional intercellular communication by hepatocarcinogenic compounds

Gap junctions in liver, as in other organs, play a critical role in tissue homeostasis. Inherently, these cellular constituents are major targets for systemic toxicity and diseases, including cancer. This review provides an overview of chemicals that compromise liver gap junctions, in particular biological toxins, organic solvents, pesticides, pharmaceuticals, peroxides, metals and phthalates. The focus in this review is placed upon the mechanistic scenarios that underlie these adverse effects. Further, the potential use of gap junctional activity as an in vitro biomarker to identify non-genotoxic hepatocarcinogenic chemicals is discussed.

Molecular Targets of Natural Products for Chondroprotection in Destructive Joint Diseases

Osteoarthritis (OA) is the most common type of arthritis that occurs in an aged population. It affects any joints in the body and degenerates the articular cartilage and the subchondral bone. Despite the pathophysiology of OA being different, cartilage resorption is still a symbol of osteoarthritis. Matrix metalloproteinases (MMPs) are important proteolytic enzymes that degrade extra-cellular matrix proteins (ECM) in the body. MMPs contribute to the turnover of cartilage and its break down; their levels have increased in the joint tissues of OA patients. Application of chondroprotective drugs neutralize the activities of MMPs. Natural products derived from herbs and plants developed as traditional medicine have been paid attention to, due to their potential biological effects. The therapeutic value of natural products in OA has increased in reputation due to their clinical impact and insignificant side effects. Several MMPs inhibitor have been used as therapeutic drugs, for a long time. Recently, different types of compounds were reviewed for their biological activities. In this review, we summarize numerous natural products for the development of MMPs inhibitors in arthritic diseases and describe the major signaling targets that were involved for the treatments of these destructive joint diseases.

Quantitative Proteome Analysis of Jatropha curcas L. Genotypes with Contrasting Levels of Phorbol Esters

The phorbol esters in the seeds of Jatropha curcas are a major hindrance to the full exploitation of the potential of this oil crop as a source of raw material for the production of biodiesel. Here, various quantitative proteomic strategies are used to establish the proteomes of roots, leaves, and endosperm of two genotypes of J. curcas with contrasting levels of phorbol esters in the seeds. In total 4532, 1775, and 503 proteins are identified respectively in roots, leaves, and endosperm, comprising 5068 unique proteins; of this total, 185 are differentially abundant in roots, 72 in leaves, and 20 in the endosperm. The biosynthetic pathways for flavonoids and terpenoids are well represented in roots, including the complete set of proteins for the mevalonate and non-mevalonate/Deoxyxylulose 5-Phosphate pathways, and proteins involved in the branches which lead to the synthesis tricyclic diterpenoids and gibberellins. Also, casbene synthase which catalyzes the first committed step in the biosynthesis of tigliane-type diterpenes is identified in roots of both genotypes, but not in leaves and endosperm. This dataset will be a valuable resource to explore the biochemical basis of the low toxicity of Jatropha genotypes with low concentration of phorbol esters in the seeds.

Total synthesis of crotophorbolone

As a natural diterpenoid, crotophorbolone possesses a challenging trans,trans-5/7/6 framework decorated with six contiguous stereogenic centers and is structurally and biogenetically related to tigliane-type diterpenoids with intriguing bioactivities such as phorbol and prostratin. Based on the convergent strategy, we completed an eighteen-step total synthesis of crotophorbolone starting from (−)-carvone and (+)-dimethyl-2,3-O-isopropylidene-l-tartrate. The key elements of the synthesis involve expedient installation of the six-membered ring and the five-membered ring with multiple functional groups at an early stage, cyclization of the seven-membered ring through alkenylation of the ketone between the five-membered ring and the six-membered ring, functional group-sensitive ring-closing metathesis and final selective introduction of hydroxyls at C₂₀ and C₄.

Convergent total synthesis of crotophorbolone was accomplished in 18 longest linear steps. Observation of unexpected thermodynamic stability of a cis,trans-5/7/6 tricycle would benefit synthetic design of tigliane- and daphnane-related diterpenoids.