Emodin has a cytotoxic activity against human multiple myeloma as a Janus-activated kinase 2 inhibitor

Cytotoxic and Antitumor Agents from Genus Rubia

Genus Rubia is widely distributed in almost all regions of the world, with 36 species and 2 varieties in China. Rubia species, such as Rubia cordifolia, have been used in traditional Chinese medicine for the treatment of diseases since ancient times. In recent years, the study of anticancer effects in traditional Chinese medicine has become a popular topic, and some studies have shown that several Rubia species extracts have cytotoxic and antitumor effects, and some of them have been shown to contain specific antitumor agents. Therefore, this review focuses on the cytotoxic and antitumor effects of the chemical constituents contained in Genus Rubia. Summarized 71 types of chemical substances in 5 categories with the effect of cytotoxicity and antitumor, as well as their structures, targets and mechanisms of action.

Reynoutria japonica consisted of emodin-8-β-D-glucoside ameliorates Dermatophagoides farinae extract-induced atopic dermatitis-like skin inflammation in mice by inhibiting JAK/STAT signaling

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by skin barrier dysfunction and chronic inflammatory responses. Reynoutria japonica, known as Huzhang in traditional Chinese Medicine, can enhance blood circulation to eliminate wind pathogens and terminate coughing. Despite pharmacological evidence supporting the efficacy of R. japonica in suppressing edema-induced skin inflammation or connective tissue diseases, its pharmaceutical potential for treating AD-like skin inflammation remains unexplored. This study investigated the possible effects of R. japonica ethanol extract (RJE) on Dermatophagoides farinae extract (DfE)-induced AD-like skin inflammation in NC/Nga mice. To elucidate the underlying mechanisms by which RJE inhibits skin inflammation, we examined the effect of RJE on IFN-γ/TNF-α-induced signal transducer and activator of transcription (STAT) signaling in human epidermal keratinocytes (HEKs) and human dermal fibroblasts (HDFs). Our findings revealed that RJE mitigates DfE-induced AD-like symptoms and skin barrier disruptions in mouse skin lesions. Moreover, RJE attenuated DfE-induced mast cell infiltration and serum levels of inflammatory cytokines (IL-1α, IL-1β, IL-6, IL-23, IFN-γ, TNF-α, and GM-CSF). RJE also inhibited IFN-γ/TNF-α-induced chemokine levels and STAT3 phosphorylation in HEKs and HDFs. Virtual binding analysis of the RJE components suggested that emodin-8-β-D-glucoside binds to Janus kinase (JAK) 1/2, thereby suppressing STAT signaling, which was confirmed by Western blot analysis. In conclusion, our results suggest that RJE may alleviate DfE-induced skin barrier dysfunction by inhibiting JAK/STAT signaling and the proinflammatory immune response through the suppression of inflammatory mediators in AD-like skin disease. These findings suggest that RJE has potential as an effective therapy for AD management.

In Silico and In Vitro Study of Janus Kinases Inhibitors from Naphthoquinones

Janus kinases (JAKs) are involved in numerous cellular signaling processes related to immune cell functions. JAK2 and JAK3 are associated with the pathogenesis of leukemia and common lymphoid-derived illnesses. JAK2/3 inhibitors could reduce the risk of various diseases by targeting this pathway. Herein, the naphthoquinones were experimentally and theoretically investigated to identify novel JAK2/3 inhibitors. Napabucasin and 2'-methyl napabucasin exhibited potent cell growth inhibition in TF1 (IC₅₀ = 9.57 and 18.10 μM) and HEL (IC₅₀ = 3.31 and 6.65 μM) erythroleukemia cell lines, and they significantly inhibited JAK2/3 kinase activity (in a nanomolar range) better than the known JAK inhibitor, tofacitinib. Flow cytometric analysis revealed that these two compounds induced apoptosis in TF1 cells in a time and dose-dependent manner. From the molecular dynamics study, both compounds formed hydrogen bonds with Y931 and L932 residues and hydrophobically contacted with the conserved hinge region, G loop, and catalytic loop of the JAK2. Our obtained results suggested that napabucasin and its methylated analog were potential candidates for further development of novel anticancer drug targeting JAKs.

Emodin coupled with high LET neutron beam-a novel approach to treat on glioblastoma

The primary motivation of this investigative study is trying to find an alternative treatment that can be used to slow down or treat glioblastoma due to the witnessed toxic side effects of the current drugs coupled with limited effectiveness in overall treatment. Consequently, a Chinese plant extract emodin proves to play a critical role in this investigative study since results from the Western blot and the other accompanying assays for anti-cancer effects indicate that it cannot work a lot to suppress cell migration and possible invasion, but rather emodin can be combined with radiation to give desired outcomes. Our result shows that the kind of radiation which acts well with emodin is neutron radiation rather than gamma radiation. Emodin significantly enhanced the radiosensitivity of LN18 and LN428 cells to γ-rays through MTT assay and cell counting. Accordingly, exposure to neutron radiation in the presence of emodin induced apoptotic cell death and autophagic cell death to a significantly higher extent, and suppressed cell migration and invasiveness more robustly. These effects are presumably due to the ability of emodin to amplify the effective dose from neutron radiation more efficiently. Thus, the study below is one such trial towards new interventional discovery and development in relation to glioblastoma treatment.

Ultrasound-Assisted Encapsulation of Anthraquinones Extracted from Aloe-Vera Plant into Casein Micelles

Aloe-vera extracted anthraquinones (aloin, aloe-emodin, rhein) possess a wide range of biological activities, have poor solubility and are sensitive to processing conditions. This work investigated the ultrasound-assisted encapsulation of these extracted anthraquinones (AQ) into casein micelles (CM). The particle size and zeta potential of casein micelles loaded with aloin (CMA), aloe-emodin (CMAE), rhein (CMR) and anthraquinone powder (CMAQ) ranged between 171–179 nm and −23 to −17 mV. The AQ powder had the maximum encapsulation efficiency (EE%) (aloin 99%, aloe-emodin 98% and rhein 100%) and encapsulation yield, while the whole leaf Aloe vera gel (WLAG) had the least encapsulation efficiency. Spray-dried powder (SDP) and freeze-dried powder (FDP) of Aloe vera showed a significant increase in size and zeta potential related to superficial coating instead of encapsulation. The significant variability in size, zeta potential and EE% were related to anthraquinone type, its binding affinity, and its ratio to CM. FTIR spectra confirmed that the structure of the casein micelle remained unchanged with the binding of anthraquinones except in casein micelles loaded with whole-leaf aloe vera gel (CMWLAG), where the structure was deformed. Based on our findings, Aloe vera extracted anthraquinones powder (AQ) possessed the best encapsulation efficiency within casein micelles without affecting its structure. Overall, this study provides new insights into developing new product formulations through better utilization of exceptional properties of casein micelles.

Molecular mechanism of Rhubarb in the treatment of non-small cell lung cancer based on network pharmacology and molecular docking technology

Non-small cell lung cancer (NSCLC) is one of the leading causes of death in the world. Rhubarb, a traditional Chinese medicine, has been widely used in the treatment of inflammatory and autoimmune diseases. This study aimed to investigate the possible mechanism of the rhubarb herb in the treatment of NSCLC by means of network pharmacology and molecular docking and to provide a theoretical basis for experiments and clinical application of traditional Chinese medicine for treating lung cancer. The main active chemical components and targets of rhubarb were screened through Swiss Target Prediction, TargetNet, and Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. The protein-protein interaction (PPI) network was built via an in-depth exploration of the relationships between the proteins. The enrichment analyses of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were applied to predict the potential roles in the pathogenesis of NSCLC via the R package cluster Profiler. Potential targets and active ingredients associated with anti-tumor effects of rhubarb were screened by reverse molecular docking. By searching databases and literature, a total of 295 targets were found for the 21 active ingredients in rhubarb. There were 68 common target genes associated with NSCLC, of which 9 are derived from FDA-approved drugs. GO Gene Set Enrichment Analysis (GSEA) explored up to 1103 biological processes, 62 molecular functions, and 18 cellular components. KEGG GSEA explored 65 basic pathways, and 71 disease pathways. Four key targets (JUN, EGFR, BCL2, and JAK2) were screened through the protein-protein interaction network, target-pathway network, and FDA drug-target network. Molecular docking results showed that these key targets had relatively strong binding activities with rhubarb's active ingredients. The present study explored the potential pharmacological mechanisms of rhubarb on NSCLC, promoting the clinical application of rhubarb in treating NSCLC, and providing references for advanced research.

Emodin Ameliorates the Efficacy of Carfilzomib in Multiple Myeloma Cells via Apoptosis and Autophagy

Background: Carfilzomib, the proteasome inhibitor, can increase the overall survival rate of multiple myeloma (MM) patients undergoing targeted therapy. However, relapse and toxicity present great challenges for such treatment, so an urgent need for effective combination therapy is necessary. Emodin is a natural chemical compound that inhibits the proliferation of various cancers and can effectively combine with other treatments. In this study, we evaluated the sensitizing effect of emodin combined with carfilzomib on MM cells. Methods: The cells were treated with emodin, carfilzomib, and a combination of drugs to determine their effects on cell proliferation and viability. The cell cycle distribution and reactive oxygen species (ROS) expression were measured by flow cytometry. The level of RNA and protein were analyzed through real-time qPCR and immunoblotting. Results: Emodin acted synergistically with carfilzomib to reduce the proliferation and viability of MM cell lines in vitro. Furthermore, the combination of emodin and carfilzomib increased ROS production, inducing apoptosis and autophagy pathways via caspase-3, PARP, p62, and LC3B. Conclusions: These results provide a molecular target for combination therapy in MM patients.

Cancer Chemoprevention: A Strategic Approach Using Phytochemicals

Cancer chemoprevention approaches are aimed at preventing, delaying, or suppressing tumor incidence using synthetic or natural bioactive agents. Mechanistically, chemopreventive agents also aid in mitigating cancer development, either by impeding DNA damage or by blocking the division of premalignant cells with DNA damage. Several pre-clinical studies have substantiated the benefits of using various dietary components as chemopreventives in cancer therapy. The incessant rise in the number of cancer cases globally is an issue of major concern. The excessive toxicity and chemoresistance associated with conventional chemotherapies decrease the success rates of the existent chemotherapeutic regimen, which warrants the need for an efficient and safer alternative therapeutic approach. In this scenario, chemopreventive agents have been proven to be successful in protecting the high-risk populations from cancer, which further validates chemoprevention strategy as rational and promising. Clinical studies have shown the effectiveness of this approach in managing cancers of different origins. Phytochemicals, which constitute an appreciable proportion of currently used chemotherapeutic drugs, have been tested for their chemopreventive efficacy. This review primarily aims to highlight the efficacy of phytochemicals, currently being investigated globally as chemopreventives. The clinical relevance of chemoprevention, with special emphasis on the phytochemicals, curcumin, resveratrol, tryptanthrin, kaempferol, gingerol, emodin, quercetin genistein and epigallocatechingallate, which are potential candidates due to their ability to regulate multiple survival pathways without inducing toxicity, forms the crux of this review. The majority of these phytochemicals are polyphenols and flavanoids. We have analyzed how the key molecular targets of these chemopreventives potentially counteract the key drivers of chemoresistance, causing minimum toxicity to the body. An overview of the underlying mechanism of action of these phytochemicals in regulating the key players of cancer progression and tumor suppression is discussed in this review. A summary of the clinical trials on the important phytochemicals that emerge as chemopreventives is also incorporated. We elaborate on the pre-clinical and clinical observations, pharmacokinetics, mechanism of action, and molecular targets of some of these natural products. To summarize, the scope of this review comprises of the current status, limitations, and future directions of cancer chemoprevention, emphasizing the potency of phytochemicals as effective chemopreventives.

Journey of anthraquinones as anticancer agents - a systematic review of recent literature

Anthraquinones are privileged chemical scaffolds that have been used for centuries in various therapeutic applications. The anthraquinone moiety forms the core of various anticancer agents. However, the emergence of drug-resistant cancers warrants the development of new anticancer agents. The research endeavours towards new anthraquinone-based compounds are increasing rapidly in recent years. They are used as a core chemical template to achieve structural modifications, resulting in the development of new anthraquinone-based compounds as promising anticancer agents. Mechanistically, most of the anthraquinone-based compounds inhibit cancer progression by targeting essential cellular proteins. Herein, we review new anthraquinone analogues that have been developed in recent years as anticancer agents. This includes a systematic review of the recent literature (2005-2021) on anthraquinone-based compounds in cell-based models and key target proteins such as kinases, topoisomerases, telomerases, matrix metalloproteinases and G-quadruplexes involved in the viability of cancer cells. In addition to this, the developments in PEG-based delivery of anthraquinones and the toxicity aspects of anthraquinone derivatives are also discussed. The review dispenses a compact background knowledge to understanding anthraquinones for future research on the expansion of anticancer therapeutics.

Emodin - A natural anthraquinone derivative with diverse pharmacological activities

Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) is a natural anthraquinone derivative that is present in numerous globally renowned herbal medicines. It is recognised as a protein tyrosine kinase inhibitor and as an anticancer drug, active against various tumour cells, including lung, breast, liver, and ovarian cancer cells. Recently, its role in combination chemotherapy with various allopathic medicines, to minimize their toxicity and to enhance their efficacy, has been studied. The use of emodin in these therapies is gaining popularity, due to fewer associated side effects compared with standard anticancer drugs. Emodin has a broad therapeutic window, and in addition to its antineoplastic activity, it displays anti-ulcer, anti-inflammatory, hepatoprotective, neuroprotective, antimicrobial, muscle relaxant, immunosuppressive and antifibrotic activities, in both in vitro and in vivo models. Although reviews on the anticancer activity of emodin have been published, none coherently unite all the pharmacological properties of emodin, particularly the anti-oxidant, antimicrobial, antidiabetic, immunosuppressive and hepatoprotective activities of the compound. Hence, in this review, all of the available data regarding the pharmacological properties of emodin are explored, with particular emphasis on the modes of action of the molecule. In addition, the manuscript details the occurrence, biosynthesis and chemical synthesis of the compound, as well as its toxic effects on biotic systems.

Improving the Condition of European Hare Through Nutrition

The objective of the article is to evaluate the effects of a newly designed granulated mixture enriched with Bohemian knotweed (Reynoutria x bohemica) on European hare (Lepus europaeus) kept at closed farms. The positive influence of knotweed on the microbiome in the digestive system and better usage of the fodder were proven based on biochemical and haematological analysis of blood. Lower manifestation of pathogenic organisms is also expected. Finally, the positive influence on higher weight gains in baby hares was proven, which improves their condition. The results can be used in practice at closed farms breeding European hare focused on releasing bred young hares into open hunting grounds where it is possible to obtain a monetary contribution for the releasing of hares from a grant of the Ministry of Agriculture of the Czech Republic in the field of hunting. Furthermore, the results can be used for feeding hares in open hunting grounds.

Aloe and its Effects on Cancer: A Narrative Literature Review

Many years ago, Aloe Vera was cited to have a lot of therapeutic properties including; anti-microbial, anti-viral, anti-cancer, anti-oxidant, anti-inflammatory, skin protection, wound healing, and regulation of blood glucose and cholesterol. However, Aloe could present some side effects. This review focused on the latest discoveries regarding the therapeutic role of Aloe plant or its compounds on the acquired biological capabilities for tumour growth and progression namely; evading growth suppressor, avoiding immune destruction, enabling replicative immortality, tumour promoting inflammation, activating invasion and metastasis, inducing angiogenesis, genome instability and mutation, resisting cell death, deregulating cellular energetics and sustaining proliferating signalling. It clarified the anti-cancer activities it exerts on different types of cancer and also highlighted some pro-oncogenic pathways that can be disrupted by different compounds of Aloe.

Is Emodin with Anticancer Effects Completely Innocent? Two Sides of the Coin

Many anticancer active compounds are known to have the capacity to destroy pathologically proliferating cancer cells in the body, as well as to destroy rapidly proliferating normal cells. Despite remarkable advances in cancer research over the past few decades, the inclusion of natural compounds in researches as potential drug candidates is becoming increasingly important. However, the perception that the natural is reliable is an issue that needs to be clarified. Among the various chemical classes of natural products, anthraquinones have many biological activities and have also been proven to exhibit a unique anticancer activity. Emodin, an anthraquinone derivative, is a natural compound found in the roots and rhizomes of many plants. The anticancer property of emodin, a broad-spectrum inhibitory agent of cancer cells, has been detailed in many biological pathways. In cancer cells, these molecular mechanisms consist of suppressing cell growth and proliferation through the attenuation of oncogenic growth signaling, such as protein kinase B (AKT), mitogen-activated protein kinase (MAPK), HER-2 tyrosine kinase, Wnt/-catenin, and phosphatidylinositol 3-kinase (PI3K). However, it is known that emodin, which shows toxicity to cancer cells, may cause kidney toxicity, hepatotoxicity, and reproductive toxicity especially at high doses and long-term use. At the same time, studies of emodin, which has poor oral bioavailability, to transform this disadvantage into an advantage with nano-carrier systems reveal that natural compounds are not always directly usable compounds. Consequently, this review aimed to shed light on the anti-proliferative and anti-carcinogenic properties of emodin, as well as its potential toxicities and the advantages of drug delivery systems on bioavailability.

Multiple Myeloma Inhibitory Activity of Plant Natural Products

A literature search on plant natural products with antimyeloma activity until the end of 2020 resulted in 92 compounds with effects on at least one human myeloma cell line. Compounds were divided in different compound classes and both their structure-activity-relationships as well as eventual correlations with the pathways described for Multiple Myeloma were discussed. Each of the major compound classes in this review (alkaloids, phenolics, terpenes) revealed interesting candidates, such as dioncophyllines, a group of naphtylisoquinoline alkaloids, which showed pronounced and selective induction of apoptosis when substituted in position 7 of the isoquinoline moiety. Interestingly, out of the phenolic compound class, two of the most noteworthy constituents belong to the relatively small subclass of xanthones, rendering this group a good starting point for possible further drug development. The class of terpenoids also provides noteworthy constituents, such as the highly oxygenated diterpenoid oridonin, which exhibited antiproliferative effects equal to those of bortezomib on RPMI8226 cells. Moreover, triterpenoids containing a lactone ring and/or quinone-like substructures, e.g., bruceantin, whitaferin A, withanolide F, celastrol, and pristimerin, displayed remarkable activity, with the latter two compounds acting as inhibitors of both NF-κB and proteasome chymotrypsin-like activity.

The Effect of Reynoutria × Bohemica on the Condition of Capreolus Capreolus and Cervus Elaphus

The objective of the work is to evaluate the effects of a granulated feeding mixture enriched with knotweed (Reynoutria × bohemica) on roe deer (Capreolus capreolus) bred at a closed farm and red deer (Cervus elaphus) bred at a farm. Based on both biochemical and haematological blood analysis, the knotweed is expected to have an influence on the microbiome in the digestive system as well as allowing better utilisation of fodder and lower manifestation of pathogenic organisms. The results are of practical use mainly on farms and in hobby breeding but also in deer parks. Furthermore, the results may be used for feeding deer in open hunting grounds.

In Vitro Investigation of the Cytotoxic Activity of Emodin 35 Derivative on Multiple Myeloma Cell Lines

Background

Bortezomib is used for treating multiple myeloma (MM); however, it has considerable adverse effects. Emodin has been reported to exhibit inhibitory effects on MM cell lines. We investigated the efficacy of emodin 35 (E35), an emodin derivative, using U266 and MM1s cell lines in treating MM and the efficacy of combining bortezomib and E35.

Methods

MTT assays were used to observe the effects of E35 on MM cell growth. The effects on cellular apoptosis were then observed using Annexin V/propidium iodide (PI) staining assay. The expression of apoptosis-related genes, including the caspase family, was examined. The efficacy of combining bortezomib and E35 was investigated by examining the expression of the Akt/mTOR/4EBP1 signaling pathway-related proteins.

Results

We report that E35 inhibited the growth of U266 and MM1s cells by inducing cellular apoptosis. Moreover, E35 downregulated the expression of apoptosis-related genes and suppressed the phosphorylation of Akt/mTOR/4EBP1 signaling pathway-related genes, thus exhibiting synergistic effects with bortezomib. All observed effects were dose-dependent.

Conclusion

The results showed that E35 exhibited cytotoxic effects in MM cell lines in protein levels. Thus, E35, particularly in combination with bortezomib, may be considered as a promising treatment for MM; however, this requires further investigation in vivo.

Compounds from Natural Sources as Protein Kinase Inhibitors

The advantage of natural compounds is their lower number of side-effects when compared to most synthetic substances. Therefore, over the past several decades, the interest in naturally occurring compounds is increasing in the search for new potent drugs. Natural compounds are playing an important role as a starting point when developing new selective compounds against different diseases. Protein kinases play a huge role in several diseases, like cancers, neurodegenerative diseases, microbial infections, or inflammations. In this review, we give a comprehensive view of natural compounds, which are/were the parent compounds in the development of more potent substances using computational analysis and SAR studies.

Anthraquinone: a promising scaffold for the discovery and development of therapeutic agents in cancer therapy

Cancer, characterized by uncontrolled malignant neoplasm, is a leading cause of death in both advanced and emerging countries. Although, ample drugs are accessible in the market to intervene with tumor progression, none are totally effective and safe. Natural anthraquinone (AQ) equivalents such as emodin, aloe-emodin, alchemix and many synthetic analogs extend their antitumor activity on different targets including telomerase, topoisomerases, kinases, matrix metalloproteinases, DNA and different phases of cell lines. Nano drug delivery strategies are advanced tools which deliver drugs into tumor cells with minimum drug leakage to normal cells. This review delineates the way AQ derivatives are binding on these targets by abolishing tumor cells to produce anticancer activity and purview of nanoformulations related to AQ analogs.

Preparation and Evaluation of Novel Emodin-loaded Stearic Acid-g-chitosan Oligosaccharide Nanomicelles

The purpose of this study was to prepare and characterize emodin-loaded stearic acid-g-chitosan oligosaccharide (CSO-SA/EMO) and to evaluate its antitumor activity in vitro. In this study, stearic acid-g-chitosan oligosaccharide was used as a carrier and its physicochemical properties were determined by different methods. Cell uptake behavior was examined using FITC-labeled stearic acid-g-chitosan oligosaccharide. CSO-SA/EMO was prepared using ultrasonication and dialysis. Particle size, surface potential, entrapment efficiency, and drug release behavior were studied in vitro. The effects of CSO-SA/EMO on gastric cancer cells were investigated using MTT assay and flow cytometry. Results showed CSO-SA/EMO particle size was larger and potential was smaller than that of stearic acid-g-chitosan oligosaccharide. The 12 h micellar uptake by MGC803 and BGC823 cells was sufficient, and the micelles were able to abundantly accumulate at lesion sites in mice thus achieving good passive EPR targeting. MTT and cell cycle arrest assays showed CSO-SA/EMO-enhanced antitumor activity significantly towards MGC803 and BGC823 cells compared with that of free emodine. Tumor volume, hematoxylin and eosin staining, and terminal deoxynucleotide transferase dUTP nick-end labeling assay proved CSO-SA/EMO had a significant antitumor effect on tumor tissues in vivo. In conclusion, the ultrasonication-dialysis method provided a simple and effective method for preparing CSO-SA/EMO. The delivery of emodine using a micelle system improved its antitumor effects effectively.

Impact of Natural Dietary Agents on Multiple Myeloma Prevention and Treatment: Molecular Insights and Potential for Clinical Translation

Chemoprevention is based on the use of non-toxic, pharmacologically active agents to prevent tumor progression. In this regard, natural dietary agents have been described by the most recent literature as promising tools for controlling onset and progression of malignancies. Extensive research has been so far performed to shed light on the effects of natural products on tumor growth and survival, disclosing the most relevant signal transduction pathways targeted by such compounds. Overall, anti-inflammatory, anti-oxidant and cytotoxic effects of dietary agents on tumor cells are supported either by results from epidemiological or animal studies and even by clinical trials. Multiple myeloma is a hematologic malignancy characterized by abnormal proliferation of bone marrow plasma cells and subsequent hypercalcemia, renal dysfunction, anemia, or bone disease, which remains incurable despite novel emerging therapeutic strategies. Notably, increasing evidence supports the capability of dietary natural compounds to antagonize multiple myeloma growth in preclinical models of the disease, underscoring their potential as candidate anti-cancer agents. In this review, we aim at summarizing findings on the anti-tumor activity of dietary natural products, focusing on their molecular mechanisms, which include inhibition of oncogenic signal transduction pathways and/or epigenetic modulating effects, along with their potential clinical applications against multiple myeloma and its related bone disease.

Mcl-1 as a "barrier" in cancer treatment: Can we target it now?

During the last two decades, the study of Mcl-1, an anti-apoptotic member of the Bcl-2 family, attracted researchers due to its important role in cancer cell survival and tumor development. The significance of Mcl-1 protein in resistance to chemotherapeutics makes it an attractive target in cancer therapy. Here, we discuss the diverse possibilities for indirect Mcl-1 inhibition through its downregulation, for example, via targeting for proteasomal degradation or blockage of translation and transcription. We also provide an overview of the direct blocking of protein-protein interactions with pro-apoptotic Bcl-2 family proteins, including examples of the most promising regulators of Mcl-1 and selective BH3-mimetics, which at present are under clinical evaluation. Moreover, several approaches for the co-targeting of Mcl-1 and other proteins (e.g., CDKs) are also presented. In addition, we highlight the broad spectrum of problems that accompanied the discovery and development of effective Mcl-1 inhibitors.

Co-occurrence of DON and Emerging Mycotoxins in Worldwide Finished Pig Feed and Their Combined Toxicity in Intestinal Cells

Food and feed can be naturally contaminated by several mycotoxins, and concern about the hazard of exposure to mycotoxin mixtures is increasing. In this study, more than 800 metabolites were analyzed in 524 finished pig feed samples collected worldwide. Eighty-eight percent of the samples were co-contaminated with deoxynivalenol (DON) and other regulated/emerging mycotoxins. The Top 60 emerging/regulated mycotoxins co-occurring with DON in pig feed shows that 48%, 13%, 8% and 12% are produced by Fusarium, Aspergillus, Penicillium and Alternaria species, respectively. Then, the individual and combined toxicity of DON and the 10 most prevalent emerging mycotoxins (brevianamide F, cyclo-(L-Pro-L-Tyr), tryptophol, enniatins A1, B, B1, emodin, aurofusarin, beauvericin and apicidin) was measured at three ratios corresponding to pig feed contamination. Toxicity was assessed by measuring the viability of intestinal porcine epithelial cells, IPEC-1, at 48-h. BRV-F, Cyclo and TRPT did not alter cell viability. The other metabolites were ranked in the following order of toxicity: apicidin > enniatin A1 > DON > beauvericin > enniatin B > enniatin B1 > emodin > aurofusarin. In most of the mixtures, combined toxicity was similar to the toxicity of DON alone. In terms of pig health, these results demonstrate that the co-occurrence of emerging mycotoxins that we tested with DON does not exacerbate toxicity.

Anticancer Activity and Underlying Mechanism of Phytochemicals against Multiple Myeloma

Multiple myeloma (MM)-a common hematologic malignancy of plasma cells-accounts for substantial mortality and morbidity rates. Due to the advent of novel therapies such as immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs), and monoclonal antibodies (mAbs), response rates were increased and free survival and overall survival have been elevated. However, adverse events including toxicity, neuropathy or continuous relapse are still problems. Thus, development of novel drugs which have less side effects and more effective is needed. This review aims to recapitulate the pharmacologic anti-MM mechanisms of various phytochemicals, elucidating their molecular targets. Keywords related to MM and natural products were searched in PUBMED/MEDLINE. Phytochemicals have been reported to display a variety of anti-MM activities, including apoptosis, cell cycle arrest, antiangiogenesis, and miRNA modulation. Some phytochemicals sensitize the conventional therapies such as dexamethasone. Also, there are clinical trials with phytochemicals such as agaricus, curcumin, and Neovastat regarding MM treatment. Taken together, this review elucidated and categorized the evidences that natural products and their bioactive compounds could be potent drugs in treating MM.

Emodin inhibits colon cancer by altering BCL-2 family proteins and cell survival pathways

Background

Currently offered therapeutics to treat colon cancer (CoCa) are toxic when given at maximum tolerated dose to achieve optimal clinical response. Hence, less toxic therapeutic intervention is needed to treat CoCa. In this study, we investigated the effect of a natural agent, Emodin, on CoCa.

Methods

Cell viability (MTT) assay was used to determine the effect of Emodin on human CoCa and colon epithelial cells. Flow cytometric analysis was used to determine Emodin induced cell death. Antibody microarray and western blot analyses were used to determine Emodin induced molecular changes involved in cell death. Change in mitochondrial membrane potential in response to Emodin was determined by flow cytometric analysis. Expression and localization of Bcl-2 family proteins were assessed by western blot analysis.

Results

Emodin decreased viability of CoCa cells and induced apoptosis in a time and dose-dependent manner compared to vehicle-treated control without significantly impacting normal colon epithelial cells. Emodin activated caspases, modulated Bcl-2 family of proteins and reduced mitochondrial membrane potential to induce CoCa cell death. Further, changes in Bcl-2 family protein expression and localization correlated with loss in mitochondrial membrane potential. Signaling (MAPK/JNK, PI3K/AKT, NF-κβ and STAT) pathways associated with cell growth, differentiation, and Bcl-2 family expression or function were negatively regulated by Emodin.

Conclusions

Ability of Emodin to impact molecular pathways involved in cell survival and apoptosis highlight the potential of this agent as a new and less toxic alternative for CoCa treatment.

Emodin Attenuates Lipopolysaccharide-Induced Injury via Down-Regulation of miR-223 in H9c2 Cells

Emodin is a natural product extracted from Rheum palmatum. There are few recent studies on emodin in the treatment of myocarditis. This study aimed to investigate the effect of emodin on lipopolysaccharide (LPS)-induced inflammatory injury in cardiomyocytes. H9c2 cells were treated with 10 μM of LPS and different concentrations (0, 1, 5, 10, 15, and 20 μM) of emodin. The expression of miR-223 was changed by transient transfection. Thereafter, cell viability, apoptosis, the expression of CyclinD1 and Jnk-associated proteins, and the release of pro-inflammatory factors were assessed by cell Counting Kit-8, flow cytometry analysis, quantitative real-time polymerase chain reaction Western blot, and enzyme-linked immunosorbent assay respectively. The results showed that 20 μM of emodin significantly decreased H9c2 cells viability. LPS significantly damaged H9c2 cells, as cell viability was reduced, CyclinD1 was down-regulated, apoptosis was induced, the release of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-alpha were increased, and the phosphorylation of Jnk and c-Jun were promoted. Emodin protected H9c2 cells against LPS-induced inflammatory injury. miR-223 expression was significantly up-regulated by LPS exposure, while emodin lessened this up-regulation. LPS-injured H9c2 cells were attenuated by the overexpression of miR-223; emodin has protective actions on LPS-injured H9c2 cells and targets. Besides, SP600125 (an inhibitor of Jnk) eliminated miR-223-modulated inflammatory injury in H9c2 cells. These data demonstrated that emodin could attenuate LPS-induced inflammatory injury and deactivate Jnk signaling pathway through down-regulation of miR-223.

Inflammation, a Double-Edge Sword for Cancer and Other Age-Related Diseases

Increasing evidence from diverse sources during the past several years has indicated that long-term, low level, chronic inflammation mediates several chronic diseases including cancer, arthritis, obesity, diabetes, cardiovascular diseases, and neurological diseases. The inflammatory molecules and transcription factors, adhesion molecules, AP-1, chemokines, C-reactive protein (CRP), cyclooxygenase (COX)-2, interleukins (ILs), 5-lipooxygenase (5-LOX), matrix metalloproteinases (MMPs), nuclear factor (NF)-kB, signal transducer and activator of transcription 3 (STAT3), tumor necrosis factor (TNF), and vascular endothelial growth factor (VEGF) are molecular links between inflammation and chronic diseases. Thus, suppression of inflammatory molecules could be potential strategy for the prevention and therapy of chronic diseases. The currently available drugs against chronic diseases are highly expensive, minimally effective and produce several side effects when taken for long period of time. The focus of this review is to discuss the potential of nutraceuticals derived from “Mother Nature” such as apigenin, catechins, curcumin, ellagic acid, emodin, epigallocatechin gallate, escin, fisetin, flavopiridol, genistein, isoliquiritigenin, kaempferol, mangostin, morin, myricetin, naringenin, resveratrol, silymarin, vitexin, and xanthohumol in suppression of these inflammatory pathways. Thus, these nutraceuticals offer potential in preventing or delaying the onset of chronic diseases. We provide evidence for the potential of these nutraceuticals from pre-clinical and clinical studies.

Aloe Genus Plants: From Farm to Food Applications and Phytopharmacotherapy

Aloe genus plants, distributed in Old World, are widely known and have been used for centuries as topical and oral therapeutic agents due to their health, beauty, medicinal, and skin care properties. Among the well-investigated Aloe species are A. arborescens, A. barbadensis, A. ferox, and A. vera. Today, they account among the most economically important medicinal plants and are commonly used in primary health treatment, where they play a pivotal role in the treatment of various types of diseases via the modulation of biochemical and molecular pathways, besides being a rich source of valuable phytochemicals. In the present review, we summarized the recent advances in botany, phytochemical composition, ethnobotanical uses, food preservation, and the preclinical and clinical efficacy of Aloe plants. These data will be helpful to provide future directions for the industrial and medicinal use of Aloe plants.

Emerging Mycotoxins: Beyond Traditionally Determined Food Contaminants

Modern analytical techniques can determine a multitude of fungal metabolites contaminating food and feed. In addition to known mycotoxins, for which maximum levels in food are enforced, also currently unregulated, so-called "emerging mycotoxins" were shown to occur frequently in agricultural products. The aim of this review is to critically discuss the relevance of selected emerging mycotoxins to food and feed safety. Acute and chronic toxicity as well as occurrence data are presented for enniatins, beauvericin, moniliformin, fusaproliferin, fusaric acid, culmorin, butenolide, sterigmatocystin, emodin, mycophenolic acid, alternariol, alternariol monomethyl ether, and tenuazonic acid. By far not all of the detected compounds are toxicologically relevant at their naturally occurring levels and are therefore of little or no health concern to consumers. Still, gaps in knowledge have been identified for several compounds. These gaps should be closed by the scientific community in the coming years to allow a proper risk assessment.

Dai-Huang-Fu-Zi-Tang alleviates pulmonary and intestinal injury with severe acute pancreatitis via regulating aquaporins in rats

BACKGROUND

Dai-Huang-Fu-Zi-Tang (DHFZT) is a famous traditional Chinese prescription with intestinal obstruction, acute pancreatitis and cholecystalgia for thousands of years. Our previous work found that DHFZT could act against pulmonary and intestinal pathological injury in rats with severe acute pancreatitis (SAP). But the underlying mechanism has not been fully elucidated. The aim of present study was to investigate whether DHFZT could relieve pulmonary and intestinal injury by regulating aquaporins after SAP induced by sodium taurocholate in rats.

METHODS

Forty of SD rats were used for dose dependant experiments of DHFZT.Accurate-mass Time-of-flight liquid chromatography-mass spectrometry was used for qualitative screening of chemical compositions of DHFZT. Twenty-four rats were randomly divided into 3 groups: sham group (n = 8), model group (SAP, n = 8), DHFZT group (SAP with DHFZT treatment, n = 8). SAP models were established by retrograde injections of 5% sodium taurocholate solutions into rat pancreaticobiliary ducts. Blood samples were taken at 0, 12, 24, 48 h post-operation for detecting serum amylase, lipase, endotoxin, TNF-α, IL-6 and IL-10. Protein expression and location of aquaporin (AQP)1, 5, 8 and 9 were assessed by immunohistochemistry, western blot and immunofluorescence respectively.

RESULTS

The study showed that 27 kinds of chemical composition were identified, including 10 kinds in positive ion mode and 17 kinds in negative ion mode. The results showed that AQP1, AQP5 of lung, and AQP1, AQP5, AQP8 of intestine in model group were significantly lower than that of sham group (P < 0.05), and which were obviously reversed by treatment with DHFZT. In addition, protein levels of pro-inflammatory cytokines such as TNF-α, IL-6 and endotoxin in peripheral blood were significantly suppressed by DHFZT, and that anti-inflammatory cytokine like IL-10 was just opposite. Finally, we also noted that DHFZT reduced serum levels of amylase, lipase and endotoxin, and also improved edema and pathological scores of lung and intestine after SAP.

CONCLUSIONS

DHFZT ameliorated the pulmonary and intestinal edema and injury induced by SAP via the upregulation of different AQPs in lung and intestine, and suppressed TNF-α, IL-6 expression and enhanced IL-10 expression.

Emodin targets mitochondrial cyclophilin D to induce apoptosis in HepG2 cells

Emodin has demonstrated potent anticancer activity in human hepatocarcinoma cells and animal models, however, the cellular targets of emodin have not been fully defined. Here we report that emodin induces the dysfunction of mitochondria and the apoptosis in HepG2 cells through an enrichment in mitochondria. Specifically, A mitochondrial matrix protein (cyclophilin D, CyPD) is involved in emodin-induced apoptosis, and the inhibitor of CyPD (cyclosporin A) could almost completely suppressing the apoptosis; Moreover, as the expression of CyPD could be effectively inhibited by antioxidant N-acetyl-l-cysteine and epidermal growth factor (the activator of ERK), reactive oxygen species and ERK might be involved in the relevant role of CyPD. A further molecule-docking discloses the existence of three hydrogen-bonds in CyPD-emodin complex. Thus, target localization and CyPD in mitochondria provides an insight into the action of emodin in the treatment of liver cancer.

Aloe-Emodin Enhances Tamoxifen Cytotoxicity by Suppressing Ras/ERK and PI3K/mTOR in Breast Cancer Cells

Aloe-emodin (AE) is derived from Aloe vera and rhubarb (Rheum palmatum) and exhibits anticancer activities via multiple regulatory mechanisms in various cancers. AE can also enhance the anticancer efficacy of cisplatin, doxorubicin, docetaxel, and 5-fluorouracil; however, its effects remain poorly characterized. MCF-7, MDA-MB-231, MDA-MB-468, BT-474, and HCC-1954 breast cancer cell lines were treated with the indicated conditions of AE, and cell viability assays were performed. The expression levels of signaling proteins were determined by western blot analysis, intracellular reactive oxygen species (ROS), cell cycle distributions, and rates of apoptosis as estimated by flow cytometry. In comparison with other cells, MCF-7 cells were more sensitive to AE treatment; AE enhanced the cytotoxicity of 9[Formula: see text][Formula: see text]g/ml tamoxifen by reducing EGFR, ER[Formula: see text], Ras, ERK, c-Myc, and mTOR protein expression and blocking PI3K and mTOR activation. Finally, although co-treatment of AE with tamoxifen increased intracellular ROS, there were no effects on cell cycle progression. Besides facilitating tamoxifen-induced cell death, AE also enhanced the antiproliferative activity of tamoxifen by blocking Ras/ERK and PI3K/mTOR pathways in breast cancer cells, thus demonstrating the chemosensitizing potential of AE.

Antimicrobial structure activity relationship of five anthraquinones of emodine type isolated from Vismia laurentii

BACKGROUND

Antimicrobial activity of anthraquinone compounds of emodine type has been reported by many authors. These compounds are found in Vismia laurentii (Clusiaceae), a plant used in traditional pharmacopoeia for treatment of microbial infections among others affections. The continuous identification of new compounds has raised the problem of the relation between the structure and antimicrobial properties.

RESULTS

The yeast growth kinetics parameters were not influenced by the pH variation as it was the case for the other tested bacteria. Fungicidal activities were noted for all molecules while only few of them had bactericidal activities, mostly on Gram positive bacteria. Mathematical model establishing a quantitative relationship between physicochemical properties of molecules and their fungicidal activities were obtained for Candida albicans and showed that physicochemical properties impacting on antifungal activity were polarizability, partition coefficient, molecular weight and hydrogen bond acceptor.

CONCLUSIONS

This work demonstrated that the presence of a long aliphatic chain methoxy group substituted in position two of the emodine structure increased the antibacterial properties of the studied compounds. Moreover this antimicrobial property depends on the pH of the environment, and specifically on the polarizability and number of hydrogen bond acceptors of the compound.

Antitumor effects of deguelin on H460 human lung cancer cells in vitro and in vivo: Roles of apoptotic cell death and H460 tumor xenografts model

Deguelin, a naturally occurring rotenoid of the flavonoid family, is known to be an Akt inhibitor, to have chemopreventive activities and anti-tumor effect on several cancers. In this study, investigation to elucidate the effect of deguelin on apoptotic pathways in human lung cancer cells and on the anti-tumor effect in lung cancer xenograft nu/nu mice was performed. In vitro studies, found that deguelin induced cell morphological changes, and decreased the percentage of viability through the induction of apoptosis in H460 lung cancer cells. Deguelin triggered apoptosis in H460 cells was also confirmed by DAPI staining, DNA gel electrophoresis, and Annexin V-FITC staining and these effects are dose-dependent manners. It was also found that deguelin promoted the Ca²⁺ production and activation of caspase-3 but decreased the level of ΔΨ_m in H460 cells. Western blots indicated that the protein levels of cytochrome c, AIF, and pro-apoptotic Bax and Bak protein were increased, but the anti-apoptotic Bcl-2 and Bcl-x were decreased that may have led to apoptosis in H460 cells after exposure to deguelin. It was also confirmed by confocal laser microscope examination that deguelin promoted the release of AIF from mitochondria to cytosol. In vivo studies, found that in immunodeficient nu/nu mice bearing H460 tumor xenografts showed that the deguelin significantly suppressed tumor growth. Deguelin might be a potential therapeutic agent for the treatment of lung cancer in the future. This finding might fully support a critical event for deguelin via induction of apoptotic cell death and H460 tumor xenografts model against human lung cancer. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 84-98, 2017.

San-Huang-Xie-Xin-Tang Constituents Exert Drug-Drug Interaction of Mutual Reinforcement at Both Pharmacodynamics and Pharmacokinetic Level: A Review

Inflammatory disorders underlie varieties of human diseases. San-Huang-Xie-xin-Tang (SHXXT), composed with Rhizoma Rhei (Rheum palmatum L.), Rhizoma Coptidis (Coptis chinensis Franch), and Radix Scutellaria (Scutellaria baicalensis Georgi), is a famous formula which has been widely used in the fight against inflammatory abnormalities. Mutual reinforcement is one of the basic theories of traditional Chinese medicine. Here this article reviewed and analyzed the recent research on (1) How the main constituents of SHXXT impact on inflammation-associated signaling pathway molecules. (2) The interaction between the main constituents and efflux pumps or intestinal transporters. The goal of this work was to, (1) Provide evidence to support the theory of mutual reinforcement. (2) Clarify the key targets of SHXXT and suggest which targets need further investigation. (3) Give advice for the clinical use of SHXXT to elevated the absorption of main constituents and eventually promote oral bioavailability. We search literatures in scientific databases with key words of “each main SHXXT constituent,” in combination with “each main inflammatory pathway target molecule” or each main intestinal transporter, respectively. We report the effect of five main constituents on target molecules which lies in three main inflammatory signaling pathways, we as well investigate the interaction between constituents and intestinal transporter. We conclude, (1) The synergistic effect of constituents at both levels confirm the mutual reinforcement theory of TCM as it is proven in this work. (2) The effect of main constituents on downstream targets in nuclear need more further investigation. (3) Drug elevating the absorption of rhein, berberine and baicalein can be employed to promote oral bioavailability of SHXXT.

Emodin potentiates the antiproliferative effect of interferon α/β by activation of JAK/STAT pathway signaling through inhibition of the 26S proteasome

The 26S proteasome is a negative regulator of type I interferon (IFN-α/β) signaling. Inhibition of the 26S proteasome by small molecules may be a new strategy to enhance the efficacy of type I IFNs and reduce their side effects. Using cell-based screening assay for new 26S proteasome inhibitors, we found that emodin, a natural anthraquinone, was a potent inhibitor of the human 26S proteasome. Emodin preferably inhibited the caspase-like and chymotrypsin-like activities of the human 26S proteasome and increased the ubiquitination of endogenous proteins in cells. Computational modeling showed that emodin exhibited an orientation/conformation favorable to nucleophilic attack in the active pocket of the β1, β2, and β5 subunits of the 26S proteasome. Emodin increased phosphorylation of STAT1, decreased phosphorylation of STAT3 and increased endogenous gene expression stimulated by IFN-α. Emodin inhibited IFN-α-stimulated ubiquitination and degradation of type I interferon receptor 1 (IFNAR1). Emodin also sensitized the antiproliferative effect of IFN-α in HeLa cervical carcinoma cells and reduced tumor growth in Huh7 hepatocellular carcinoma-bearing mice. These results suggest that emodin potentiates the antiproliferative effect of IFN-α by activation of JAK/STAT pathway signaling through inhibition of 26S proteasome-stimulated IFNAR1 degradation. Therefore, emodin warrants further investigation as a new means to enhance the efficacy of IFN-α/β.

Emodin protects mice against radiation-induced mortality and intestinal injury via inhibition of apoptosis and modulation of p53

The aim of this study was to explore the protective effect of emodin, a plant-derived anthraquinone, against gamma radiation-induced mortality and intestinal injury in mice, and to investigate the radioprotective molecular mechanism. C57BL/6 male mice were pre-treated with emodin for 7days via oral gavage before gamma radiation. We found that pretreatment with emodin prolonged mice survival time after 9Gy total body irradiation (TBI). Mice were sacrificed at 1 week after 7Gy TBI, we found that emodin attenuated intestinal morphological changes and increased villus height, crypt numbers, and reduced villus and crypt apoptosis as well as inhibited the expression of p53. MTT assay, flow cytometry, Hoechst 33258 staining, real-time PCR, and Western blotting indicated that emodin pretreatment can effectively increase human umbilical venous endothelial cells (HUVECs) viability and attenuate cell apoptosis; it also inhibited the expression of p53, Bax, and Caspase3 in HUVECs after irradiation. In summary, these results suggest the potential of emodin as an effective radioprotectant against radiation-induced intestinal injury.

Emodin Inhibits Breast Cancer Growth by Blocking the Tumor-Promoting Feedforward Loop between Cancer Cells and Macrophages

Macrophage infiltration correlates with severity in many types of cancer. Tumor cells recruit macrophages and educate them to adopt an M2-like phenotype through the secretion of chemokines and growth factors, such as MCP1 and CSF1. Macrophages in turn promote tumor growth through supporting angiogenesis, suppressing antitumor immunity, modulating extracellular matrix remodeling, and promoting tumor cell migration. Thus, tumor cells and macrophages interact to create a feedforward loop supporting tumor growth and metastasis. In this study, we tested the ability of emodin, a Chinese herb-derived compound, to inhibit breast cancer growth in mice and examined the underlying mechanisms. Emodin was used to treat mice bearing EO771 or 4T1 breast tumors. It was shown that emodin attenuated tumor growth by inhibiting macrophage infiltration and M2-like polarization, accompanied by increased T-cell activation and reduced angiogenesis in tumors. The tumor inhibitory effects of emodin were lost in tumor-bearing mice with macrophage depletion. Emodin inhibited IRF4, STAT6, and C/EBPβ signaling and increased inhibitory histone H3 lysine 27 tri-methylation (H3K27m3) on the promoters of M2-related genes in tumor-associated macrophages. In addition, emodin inhibited tumor cell secretion of MCP1 and CSF1, as well as expression of surface anchoring molecule Thy-1, thus suppressing macrophage migration toward and adhesion to tumor cells. These results suggest that emodin acts on both breast cancer cells and macrophages and effectively blocks the tumor-promoting feedforward loop between the two cell types, thereby inhibiting breast cancer growth and metastasis. Mol Cancer Ther; 15(8); 1931-42. ©2016 AACR.

Identification of quinones as novel PIM1 kinase inhibitors

PIM1 is a proto-oncogene encoding the serine/threonine PIM1 kinase. PIM1 kinase plays important roles in regulating aspects of cell cycle progression, apoptosis resistance, and has been implicated in the development of such malignancies as prostate cancer and acute myeloid leukemia among others. Knockout of PIM1 kinase in mice has been shown to be non-lethal without any obvious phenotypic changes, making it an attractive therapeutic target. Our investigation of anthraquinones as kinase inhibitors revealed a series of quinone analogs showing high selectivity for inhibition of the PIM kinases. Molecular modeling studies were used to identify key interactions and binding poses of these compounds within the PIM1 binding pocket. Compounds 1, 4, 7 and 9 inhibited the growth of DU-145 prostate cancer cell lines with a potency of 8.21μM, 4.06μM, 3.21μM and 2.02μM.

Emodin Bidirectionally Modulates Macrophage Polarization and Epigenetically Regulates Macrophage Memory

Macrophages are pleiotropic cells capable of performing a broad spectrum of functions. Macrophage phenotypes are classified along a continuum between the extremes of proinflammatory M1 macrophages and anti-inflammatory M2 macrophages. The seemingly opposing functions of M1 and M2 macrophages must be tightly regulated for an effective and proper response to foreign molecules or damaged tissue. Excessive activation of either M1 or M2 macrophages contributes to the pathology of many diseases. Emodin is a Chinese herb-derived compound and has shown potential to inhibit inflammation in various settings. In this study, we tested the ability of emodin to modulate the macrophage response to both M1 and M2 stimuli. Primary mouse macrophages were stimulated with LPS/IFNγ or IL4 with or without emodin, and the effects of emodin on gene transcription, cell signaling pathways, and histone modifications were examined by a variety of approaches, including microarray, quantitative real-time PCR, Western blotting, chromatin immunoprecipitation, and functional assays. We found that emodin bidirectionally tunes the induction of LPS/IFNγ- and IL4-responsive genes through inhibiting NFκB/IRF5/STAT1 signaling and IRF4/STAT6 signaling, respectively. Thereby, emodin modulates macrophage phagocytosis, migration, and NO production. Furthermore, emodin inhibited the removal of H3K27 trimethylation (H3K27m3) marks and the addition of H3K27 acetylation (H3K27ac) marks on genes required for M1 or M2 polarization of macrophages. In conclusion, our data suggest that emodin is uniquely able to suppress the excessive response of macrophages to both M1 and M2 stimuli and therefore has the potential to restore macrophage homeostasis in various pathologies.

Antitumor Effects and Mechanism of Novel Emodin Rhamnoside Derivatives against Human Cancer Cells In Vitro

A series of novel anthracene L-rhamnopyranosides compounds were designed and synthesized and their anti-proliferative activities on cancer cell lines were investigated. We found that one derivative S-8 (EM-d-Rha) strongly inhibited cell proliferation of a panel of different human cancer cell lines including A549, HepG2, OVCAR-3, HeLa and K562 and SGC-790 cell lines, and displayed IC50 values in low micro-molar ranges, which are ten folds more effective than emodin. In addition, we found EM-d-Rha (3-(2”,3”-Di-O-acetyl-α-L-rhamnopyranosyl-(1→4)-2’,3’-di-O-acetyl-α-L-rhamnopyranosyl)-emodin) substantially induced cellular apoptosis of HepG2 and OVCAR-3 cells in the early growth stage. Furthermore, EM-d-Rha led to the decrease of mitochondrial transmembrane potential, and up-regulated the express of cells apoptosis factors in a concentration- and time-dependent manner. The results indicated the EM-d-Rha may inhibit the growth and proliferation of HepG2 cells through the pathway of apoptosis induction, and the possible molecular mechanism may due to the activation of intrinsic apoptotic signal pathway.

Glycosylation and sulfation of emodin by Gliocladium deliquescens NRRL 1086

The present study was designed to explore the substrate scope and biocatalytic capability of Gliocladium deliquescens NRRL 1086 on phenolic natural products. Emodin was subjected to the fermentation culture of Gliocladium deliquescens NRRL 1086 according to the standard two-stage protocol. The biotransformation process was monitored by HPLC-DAD-MS, the main product was isolated by column chromatography, and the structure was elucidated on the basis of NMR spectroscopy. Emodin could be fully metabolized by Gliocladium deliquescens NRRL 1086, resulting in high yield of emodin 6-O-β-D-glucopyranoside and small amount of sulfated product. In conclusion, our results may provide a convenient method to prepare emodin 6-O-β-D-glucopyranoside and the microbe catalyzed glucosylation/sulfation will give an inspiration to pharmacokinetic model studies in vitro.

Emodin inhibits tonic tension through suppressing PKCδ-mediated inhibition of myosin phosphatase in rat isolated thoracic aorta

BACKGROUND AND PURPOSE

Dysregulated tonic tension and calcium sensitization in blood vessels has frequently been observed in many cardiovascular diseases. Despite a huge therapeutic potential, little is known about natural products targeting tonic tension and calcium sensitization.

EXPERIMENTAL APPROACH

We screened natural products for inhibitory effects on vasoconstriction using the rat isolated thoracic aorta and found that an anthraquinone derivative, emodin, attenuated tonic tension. Organ bath system, primary vascular smooth muscle cells, confocal microscopy and Western blot analysis were employed to demonstrate the suppressive effects of emodin on PKCδ-mediated myosin phosphatase inhibition.

KEY RESULTS

Emodin, an active ingredient of Polygonum multiflorum extract, inhibited phenylephrine-induced vasoconstriction in rat isolated thoracic aorta, and inhibited vasoconstriction induced by 5-HT and endothelin-1. It also generally suppressed vasoconstrictions mediated by voltage-operated, store-operated calcium channels and intracellular calcium store. However, emodin did not affect agonist-induced calcium increases in primary smooth muscle cells. In contrast, post-treatment with emodin following phenylephrine stimulation potently suppressed tonic tension in rat aortic rings. Western blot analysis revealed that emodin inhibited phenylephrine-induced phospho-myosin light chain (pMLC) and the phosphorylation of myosin-targeting subunit and C-kinase-activated protein phosphatase-1 inhibitor (CPI-17). This was mediated by selective inhibition of PKCδ, whereas PKCα was not involved.

CONCLUSION AND IMPLICATIONS

Emodin attenuates tonic tension through the blockade of PKCδ and CPI-17-mediated MLC-phosphatase inhibition. This new mode of action for the suppression of tonic tension and structural insights into PKCδ inhibition revealed by emodin may provide new information for the development of modulators of tonic tension and for the treatment of hypertension.

Emodin inhibits splenocyte proliferation and inflammation by modulating cytokine responses in a mouse model system

Emodin, an anthraquinone derivative, was investigated for potential anti-inflammatory and anti-proliferative effects in vitro. The potential to induce these outcomes was assessed using concanavalin A (ConA)-stimulated mouse splenocytes. Dose-response studies showed that emodin at 100 µM was not cytotoxic to naive cells, and that the same dose caused proliferation to be significantly reduced in ConA-stimulated cells. In addition, emodin significantly reduced ConA-induced nitric oxide (NO) production and the formation/release of TH1 (IL-2, IFNγ, TNFα) and TH17 (IL-6 and IL-17) cell cytokines, but induced those of TH2 (IL-4) and Treg (IL-10) cells. From the results, it is concluded that earlier-reported immunomodulatory effects imparted by emodin may have been attributable, in part, to anti-proliferative effects on lymphocytes, as well as a shift within the TH1/TH2 and TH17/Treg balance (towards TH2 and Treg). These findings, while providing evidence of mechanisms of emodin immunomodulation, are also potentially important for sparking studies that ultimately may result in the potential use of this agent in preventive and/or corrective strategies against autoimmune and other inflammatory diseases.

Evaluation of biological properties and clinical effectiveness of Aloe vera: A systematic review

Aloe vera (蘆薈 lú huì) is well known for its considerable medicinal properties. This plant is one of the richest natural sources of health for human beings coming. The chemistry of the plant has revealed the presence of more than 200 different biologically active substances. Many biological properties associated with Aloe species are contributed by inner gel of the leaves. Most research has been centralized on the biological activities of the various species of Aloe, which include antibacterial and antimicrobial activities of the nonvolatile constituents of the leaf gel. Aloe species are widely distributed in the African and the eastern European continents, and are spread almost throughout the world. The genus Aloe has more than 400 species but few, such as A. vera, Aloe ferox, and Aloe arborescens, are globally used for trade. A. vera has various medicinal properties such as antitumor, antiarthritic, antirheumatoid, anticancer, and antidiabetic properties. In addition, A. vera has also been promoted for constipation, gastrointestinal disorders, and for immune system deficiencies. However, not much convincing information is available on properties of the gel. The present review focuses on the detailed composition of Aloe gel, its various phytocomponents having various biological properties that help to improve health and prevent disease conditions.

Emodin enhances ATRA-induced differentiation and induces apoptosis in acute myeloid leukemia cells

Emodin, an extracted natural compound from the root and rhizome of Rheum palmatum L, has been shown to have multiple biological activities including anticancer functions in previous studies. In this study, we investigated the anti-leukemic activity of emodin alone or emodin in the presence all-trans retinoic acid (ATRA) in acute myeloid leukemia (AML) cells and the potential signaling pathway involved. We demonstrated that emodin could significantly enhance the sensitivity to ATRA and present additive differentiation-inducing effects in AML cell line NB4 cells and, especially, in NB4-derived ATRA-resistant MR2 cells. Further study showed that increasing dose of emodin could effectively induce growth inhibition and apoptotic effects in both cell lines as well as in primary leukemic cells from AML patients. Moreover, the apoptotic induction in AML cells was associated with the activation of caspase cascades involving caspase-9, caspase-3, and poly(ADP-ribose) polymerase (PARP) cleavage. In addition, leukemic cell response to emodin stimuli in vitro was observed through the decreased expression levels of Bcl-2 and retinoic acid receptor α (RARα). Importantly, emodin was demonstrated as a new inhibitor of PI3K/Akt in AML cells, even in primary AML cells. It inhibited Akt phosphoration (p-Akt) at Ser473 as efficiently as mTOR at Ser2448. Consistently, it exerted suppression effects on the phosphoration of mTOR downstream targets, 4E-BP1 and p70S6K. Taken together, these findings indicate that emodin might be developed as a promising anti-leukemic agent to improve the patient outcome in AML.

Emodin inhibits growth and induces apoptosis in an orthotopic hepatocellular carcinoma model by blocking activation of STAT3

BACKGROUND AND PURPOSE

Aberrant activation of STAT3 is frequently encountered and promotes proliferation, survival, metastasis and angiogenesis in hepatocellular carcinoma (HCC). Here, we have investigated whether emodin mediates its effect through interference with the STAT3 activation pathway in HCC.

EXPERIMENTAL APPROACH

The effect of emodin on STAT3 activation, associated protein kinases and apoptosis was investigated using various HCC cell lines. Additionally, we also used a predictive tumour technology to analyse the effects of emodin . The in vivo effects of emodin were assessed in an orthotopic mouse model of HCC.

KEY RESULTS

Emodin suppressed STAT3 activation in a dose- and time-dependent manner in HCC cells, mediated by the modulation of activation of upstream kinases c-Src, JAK1 and JAK2. Vanadate treatment reversed emodin-induced down-regulation of STAT3, suggesting the involvement of a tyrosine phosphatase and emodin induced the expression of the tyrosine phosphatase SHP-1 that correlated with the down-regulation of constitutive STAT3 activation. Interestingly, silencing of the SHP-1 gene by siRNA abolished the ability of emodin to inhibit STAT3 activation. Finally, when administered i.p., emodin inhibited the growth of human HCC orthotopic tumours in male athymic nu/nu mice and STAT3 activation in tumour tissues.

CONCLUSIONS AND IMPLICATIONS

Emodin mediated its effects predominantly through inhibition of the STAT3 signalling cascade and thus has a particular potential for the treatment of cancers expressing constitutively activated STAT3.