Emodin inhibits vascular endothelial growth factor-A-induced angiogenesis by blocking receptor-2 (KDR/Flk-1) phosphorylation

Emodin disrupts the KITENIN oncogenic complex by binding ErbB4 and suppresses colorectal cancer progression in dual blockade with KSRP-binding compound

BACKGROUND

The KITENIN/ErbB4 complex has been reported to participate in metastasis, which is the principal reason of death in most colorectal cancer patients.

PURPOSE

New therapeutics need to be developed to suppress the malignant effects of the KITENIN/ErbB4 complex, which is related to drug resistance. The present study aimed to evaluate changes in cancer cell invasion capacity, transcriptional regulators, and cellular bioenergetics after targeting the KITENIN/ErbB4 complex with emodin. Moreover, we aimed to reveal the mechanistic effects of emodin and observe the dual blockade effects of ErbB4-targeted therapy with KH-type splicing regulatory protein (KSRP) and search for new alternative blockade pathways.

METHODS

Using in vitro, in vivo, molecular-docking, and metabolomics studies, we evaluated the anticancer effect of emodin alone or in combination with DKCC14S.

RESULTS

Emodin treatment decreased KITENIN and ErbB4 protein levels. The dysfunctional KITENIN/ErbB4 complex suppressed KITENIN-mediated cell invasion and downregulated AP-1 activity, aerobic glycolysis, and the levels of transcriptional regulators associated with cell metabolism. We conclude that emodin targets the KITENIN/ErbB4 complex and offering a novel mechanism by which it disrupts KITENIN-mediated signaling. Furthermore, we were demonstrated that the dual blocking effect of emodin and DKC-C14S on the KITENIN complex showed synergistic effects in suppressing colorectal cancer progression under in cell-based and animal assay.

CONCLUSION

The results suggest that co-treatment with ErbB4 and KSRP-binding compounds could constitute a potential strategy for controlling colorectal cancer progression by disrupting the KITENIN complex.

Unraveling the mechanism of the anticancer potential of emodin using 2D and spheroid models of A549 cells

The increasing global cancer burden necessitates the development of new treatment options. Herbal medicine offers a viable alternative to conventional cancer treatments. Numerous studies have shown that 3-dimensional (3D) cell culture more accurately represents tumor characteristics in vivo. Therefore, this study utilized tumor spheroids to explore the therapeutic efficacy of emodin, a natural product-derived bioactive agent. We investigated differences in chemotherapeutic response between A549 cells cultured in 2D versus spheroids, assessing key factors influencing cancer progression, including apoptosis, cell proliferation, cell cycle, migration and invasion. The findings revealed that spheroid cells displayed increased resistance to emodin compared to cells cultured in 2D. Emodin exhibited a more pronounced cytostatic effect in 2D cells, while its cytotoxic effect was more prominent in spheroid cells. Moreover, emodin treatment diminished the migratory and invasive capabilities of the cells. Mechanistic investigations indicated that emodin triggered apoptosis in A549 cells via the mitochondrial apoptotic pathway. Emodin-treated cells exhibited a significant reduction in the phosphorylation of key cancer progression pathways, including JAK2, STAT3, FAK, and ERK, compared to untreated controls. Molecular docking analysis confirmed the interactions of emodin with JAK2 and FAK. These findings suggest that the JAK2/STAT3 and FAK/ERK signaling pathways may serve as critical drivers of the therapeutic effectiveness of emodin in A549 cells.

β-asarone induces viability and angiogenesis and suppresses apoptosis of human vascular endothelial cells after ischemic stroke by upregulating vascular endothelial growth factor A

Ischemic stroke (IS) is a disease with a high mortality and disability rate worldwide, and its incidence is increasing per year. Angiogenesis after IS improves blood supply to ischemic areas, accelerating neurological recovery. β-asarone has been reported to exhibit a significant protective effect against hypoxia injury. The ability of β-asarone to improve IS injury by inducing angiogenesis has not been distinctly clarified. The experimental rats were induced with middle cerebral artery occlusion (MCAO), and oxygen-glucose deprivation (OGD) model cells were constructed using human microvascular endothelial cell line (HMEC-1) cells. Cerebral infarction and pathological damage were first determined via triphenyl tetrazolium chloride (TTC) and hematoxylin and eosin (H&E) staining. Then, cell viability, apoptosis, and angiogenesis were assessed by utilizing cell counting kit-8 (CCK-8), flow cytometry, spheroid-based angiogenesis, and tube formation assays in OGD HMEC-1 cells. Besides, angiogenesis and other related proteins were identified with western blot. The study confirms that β-asarone, like nimodipine, can ameliorate cerebral infarction and pathological damage. β-asarone can also upregulate vascular endothelial growth factor A (VEGFA) and endothelial nitric oxide synthase (eNOS) and induce phosphorylation of p38. Besides, the study proves that β-asarone can protect against IS injury by increasing the expression of VEGFA. In vitro experiments affirmed that β-asarone can induce viability and suppress apoptosis in OGD-mediated HMEC-1 cells and promote angiogenesis of OGD HMEC-1 cells by upregulating VEGFA. This establishes the potential for β-asarone to be a latent drug for IS therapy.

Blocking the ATR-SerRS-VEGFA pathway targets angiogenesis for UV-induced cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most prevalent form of skin cancer, with an escalating incidence rate and a notable potential (up to 5%) for metastasis. Ultraviolet radiation (UVA and UVB) exposure is the primary risk factor for cSCC carcinogenesis, with literature suggesting ultraviolet radiation (UVR) promotes vascular endothelial growth factor A (VEGFA) expression. This study aims to investigate UVR-induced upregulation of VEGFA and explore combination therapeutic strategies. The skin squamous cell carcinoma cell line A431 was exposed to specific durations of ultraviolet radiation. The effect of emodin on ATR/SerRS/VEGFA pathway was observed. The cell masses were also transplanted subcutaneously into mice (n = 8). ATR inhibitor combined with emodin was used to observe the growth and angiogenesis of the xenografts. The results showed that UV treatment significantly enhanced the phosphorylation of SerRS and the expression level of VEGFA in A431 cells (p < 0.05). Treatment with emodin significantly inhibited this expression (p < 0.05), and the combination of emodin and ATR inhibitor further enhanced the inhibitory effect (p < 0.05). This phenomenon was further confirmed in the xenograft model, which showed that the combination of ATR inhibitor and emodin significantly inhibited the expression of VEGFA to inhibit angiogenesis (p < 0.05), thus showing an inhibitory effect on cSCC. This study innovatively reveals the molecular mechanism of UV-induced angiogenesis in cSCC and confirms SerRS as a novel target to inhibit cSCC angiogenesis and progression in vitro and in vivo studies.

Nature's Elixir for Cancer Treatment: Targeting Tumor-induced Neovascularization

Angiogenesis, a multistep process, involves sprouting of new vessels from the pre-existing vessels in response to a stimulus in its microenvironment. Normally, angiogenesis is important for tissue maintenance and homeostasis, however it is also known to be associated with various pathologies, including cancer. Importantly, neovascularization is very crucial for tumors to grow and metastasize since it allows delivery of oxygen and nutrients as well as promotes tumor cell dissemination to distant sites. Activation of angiogenic switch is a consequence of imbalance in pro- as well as anti-angiogenic factors, that are immensely impacted by reactive oxygen species and epigenetic regulation. Several reports have suggested that angiogenic inhibitors significantly inhibit tumor growth. Therefore, anti-angiogenic therapy has gained substantial attention and has been considered a rational approach in cancer therapeutics. In this line, several anti- angiogenic drugs have been approved, however, their long term usage caused several side effects. In view of this, researchers switched to plant-based natural compounds for identifying safe and cost-effective anti-angiogenic drugs. Of note, various phytochemicals have been evaluated to reduce tumor growth by inhibiting tumor-induced angiogenesis. Moreover, the implication of nano-carriers to enhance the bioavailability of phytochemicals has proven to be more efficient anti-cancer agents. The present review highlights the existing knowledge on tumor-induced neovascularization and its regulation at the epigenetic level. Further, we emphasize the inhibitory effect of phytochemicals on tumor- induced angiogenesis that will open up new avenues in cancer therapeutics.

Therapeutic Potential of 1,8-Dihydroanthraquinone Derivatives for Breast Cancer

Breast cancer (BC) is the most common malignancy among women worldwide. In recent years, significant progress has been made in BC therapy. However, serious side effects resulting from the use of standard chemotherapeutic drugs, as well as the phenomenon of multidrug resistance (MDR), limit the effectiveness of approved therapies. Advanced research in the BC area is necessary to create more effective and safer forms of therapy to improve the outlook for individuals diagnosed with this aggressive neoplasm. For decades, plants and natural products with anticancer properties have been successfully utilized in treating various medical conditions. Anthraquinone derivatives are tricyclic secondary metabolites of natural origin that have been identified in plants, lichens, and fungi. They represent a few botanical families, e.g., Rhamnaceae, Rubiaceae, Fabaceae, Polygonaceae, and others. The review comprehensively covers and analyzes the most recent advances in the anticancer activity of 1,8-dihydroanthraquinone derivatives (emodin, aloe-emodin, hypericin, chrysophanol, rhein, and physcion) applied both individually, or in combination with other chemotherapeutic agents, in in vitro and in vivo BC models. The application of nanoparticles for in vitro and in vivo evidence in the context of 1,8-dihydroanthraquinone derivatives was also described.

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.

Usnic Acid Isolated from Usnea antarctica (Du Rietz) Reduced In Vitro Angiogenesis in VEGF- and bFGF-Stimulated HUVECs and Ex Ovo in Quail Chorioallantoic Membrane (CAM) Assay

Simple Summary

Anti-angiogenic therapy, a promising strategy against cancer progression, is limited by drug resistance. Natural plants, such as secondary metabolites of lichens, may represent an appropriate strategy to increase the effectiveness of conventional therapies and overcome resistance to anti-angiogenic therapy if combined with existing chemotherapy. Accordingly, our study was designed to determine the potential anti-angiogenic effect of usnic acid, a secondary metabolite of lichens, on VEGF- and bFGF-stimulated HUVECs as well as in quail chorioallantoic membrane assays, which were supplemented by histological sections of CAM-affected layers.

Abstract

Natural products include a diverse set of compounds of drug discovery that are currently being actively used to target tumor angiogenesis. In the present study, we evaluated the anti-angiogenic activities of secondary metabolite usnic acid isolated from Usena antarctica. We investigated the in vitro effects on proliferation, migration, and tube formation of VEGF- and bFGF-stimulated HUVECs. Ex ovo anti-angiogenic activity was evaluated using the CAM assay. Our findings demonstrated that usnic acid in the concentration of 33.57 µM inhibited VEGF (25 ng/mL) and bFGF (30 ng/mL)-induced HUVECs proliferation, migration, and tube formation. The ex ovo CAM model was used to confirm the results obtained from in vitro studies. VEGF- and bFGF-induced vessel formation was inhibited by usnic acid after 72 h in over 2-fold higher concentrations compared to in vitro. Subsequently, histological sections of affected chorioallantoic membranes were stained with hematoxylin–eosin and alcian blue to determine the number and diameter of vessels as well as the thickness of the individual CAM layers (ectoderm, mesoderm, endoderm). Usnic acid was able to suppress the formation of VEGF- and bFGF-induced vessels with a diameter of less than 100 μm, which was demonstrated by the reduction of mesoderm thickness as well.

Network Pharmacology Experiments Show That Emodin Can Exert a Protective Effect on MCAO Rats by Regulating Hif-1α/VEGF-A Signaling

Modern pharmacological studies have shown that emodin, the main effective component of rhubarb, has good anti-inflammatory and antioxidant effects, but its pharmacodynamic mechanism remains unclear yet. This study aims to elucidate the multitarget action mechanism of emodin in ischemic stroke through network pharmacology and in vivo experiments. Sprague-Dawley rats were randomly divided into control (normal saline), sham (normal saline), model (normal saline), and emodin groups (n = 9 per group). Emodin was administered at 40 mg/kg/d for 3 consecutive days. The rats were subjected to middle cerebral artery occlusion for 2 h, followed by reperfusion for 24 h to establish the cerebral ischemia-reperfusion injury. To search for relevant studies in databases, emodin, ischemic stroke, and stroke were used as keywords. Subsequently, protein-protein interaction networks and complex disease target networks were established, and an enrichment analysis and molecular docking of core targets were performed. Gene expression was detected through western blotting and reverse-transcription polymerase chain reaction. Localization and expression of proteins were detected through immunohistochemistry. Furthermore, the neurological function, 2,3,5-triphenyltetrazolium chloride staining, levels of brain tissue inflammatory factors, the role of the blood-brain barrier (BBB), and relevant signaling pathways were assessed in vivo. The molecular docking of core targets revealed that the docking between vascular endothelial growth factor A (VEGF-A) and emodin was the most efficient. Emodin pretreatment decreased the neurological score from 2.875 to 1.125. Moreover, emodin inhibited the degradation of occludin and claudin-5 caused by matrix metalloprotein kinase (MMP)-2/MMP-9, thereby protecting the BBB. Additionally, related proteins such as hypoxia-inducible factor-1α/VEGF-A and nuclear factor kappa B were down-regulated. Thus, emodin may play a protective role during cerebral ischemia reperfusion through mediation of the Hif-1α/VEGF-A signaling pathway to inhibit the expression of inflammatory factors.

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.

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.

Modulation of the triggered apoptosis by nano emodin transfersome-mediated sonodynamic therapy on head and neck squamous cell carcinoma cell lines

BACKGROUND

Non-invasive sonodynamic therapy (SDT) is a new treatment modality that uses low-intensity ultrasound to activate a non-toxic sensitizing chemical agent for cancer therapy in a site-directed manner. This study aimed to investigate the anti-cancer effects of ultrasound combined with nano emodin transfersome (NET) on head and neck squamous cell carcinoma (HNSCC) cell lines.

MATERIALS AND METHODS

A transfersome form of nano emodin as a novel sono-responsive nanomaterial was synthesized to enhance the accumulation and penetration of nanoparticles. iIn vitro experiments including hemolytic activity, cell proliferation, intracellular reactive oxygen species (ROS) generation, apoptosis induction, DNA fragmentation, and mRNA expressions of caspase 3 and 9 were conducted to explore the anti-cancer effects of NET-SDT on FaDu and CAL-27 cell lines.

RESULTS

Characterization tests showed the round and uniform morphology of NET with transfersome structure, resulting in a high drug-loading content and encapsulation efficiency. No significant hemolytic activity was observed (P > 0.05). Cytotoxicity gradually increased with increasing concentrations of NET, so that 10 × 10^-4 g/L of NET plus 5 min ultrasound irradiation at a frequency of 1 MHz and ultrasonic intensity of 2 W/cm² effectively killed 98.2 % and 97.3 % of FaDu and CAL-27 cell lines, respectively (P < 0.05). We found that ROS generation in NET-SDT was dose-dependent and the triggered apoptosis and caspase-3/9 gene expression levels were significantly enhanced as the concentration of NET increased (P < 0.05). No significant difference was found in the rate of apoptosis induction and gene expression between two cell lines.

CONCLUSIONS

Our data demonstrated that SDT with NET as a sonosensitizer can induce apoptosis and significantly decrease cell viability of HNSCC cell lines, which represents the role of NET-SDT as a potent anti-cancer modality.

Antiangiogenic properties of lichen secondary metabolites

Lichens are symbiotic organisms which are composed fungi and algae and/or cyanobacteria. They produce a variety of characteristic secondary metabolites. Such substances have various biological properties including antimicrobial, antiviral, and antitumor activities. Angiogenesis, the growth of new vessels from pre-existing vessels, contributes to numerous diseases including cancer, arthritis, atherosclerosis, infectious, and immune disorders. Antiangiogenic therapy is a promising approach for the treatment of such diseases by inhibiting the new vessel formation. Technological advances have led to the development of various antiangiogenic agents and have made possible antiangiogenic therapy in many diseases associated with angiogenesis. Some lichens and their metabolites are used in the drug industry, but many have not yet been tested for their antiangiogenic effects. The cytotoxic and angiogenic capacities of lichen-derived small molecules have been demonstrated in vivo and in vitro experiments. Therefore, some of them may be used as antiangiogenic agents in the future. The secondary compounds of lichen whose antiangiogenic effect has been studied in the literature are usnic acid, barbatolic acid, vulpinic acid, olivetoric acid, emodin, secalonic acid D, and parietin. In this article, we review the antiangiogenic effects and cellular targets of these lichen-derived metabolites.

Emodin protected against retinal ischemia insulted neurons through the downregulation of protein overexpression of β-catenin and vascular endothelium factor

Background

Emodin has been proved to have an anti-ischemic effect on the brain, however little research has been done on its effect on vision-threatening retinal ischemia. Thus, an investigation was carried out into the hypothetical efficacy of emodin against retinal ischemia and the role of β-catenin/VEGF in its therapeutic mechanism.

Methods

Retinal ischemia, followed by reperfusion (IR), was inducted by raising the intraocular pressure of a Wistar rat’s eye to 120 mmHg for 60 min. Additionally, pre-ischemic/post-ischemic intravitreous injections of emodin (4, 10 and 20 μM) or vehicle were carried out on the eye with retinal ischemia. MTT assay, electroretinograms, cresyl violet staining retinal thickness measurements, and fluorogold retrograde labelling of retinal ganglion cells (RGCs) as well as Western blotting were carried out.

Results

Cultured RGC-5 cells subjected to oxygen glucose deprivation (OGD) were used to confirm the effective concentrations of emodin (administered 1 h pre-OGD, pre-OGD emodin). The most effective and significant (P = 0.04) dose of pre-OGD emodin was observed at 0.5 μM (cell viability: 47.52 ± 3.99%) as compared to pre-OGD vehicle treatment group (38.30 ± 2.51%). Furthermore, pre-ischemic intravitreous injection of 20 μM emodin (Emo20 + IR = 0.99 ± 0.18, P < 0.001) significantly attenuated the ischemia induced reduction in ERG b-wave amplitude, as compared to pre-ischemic intravitreous vehicle (Vehicle+IR = 0.04 ± 0.02). Post-ischemic intravitreous 20 μM emodin also significantly (P < 0.001) attenuated the ischemia associated b-wave reduction (IR + Em20 = 0.24 ± 0.09). Compared with pre-ischemic intravitreous vehicle (Vehicle+IR; whole retina thickness = 71.80 ± 1.08 μm; inner retina thickness = 20.97 ± 0.85 μm; RGC =2069.12 ± 212.82/0.17mm²), the significant (P < 0.001) protective effect was also present with pre-ischemic administration of emodin. This was shown by observing cresyl violet stained retinal thickness (Emo20 + IR: whole retina = 170.10 ± 0.10 μm; inner retina = 70.65 ± 2.06 μm) and retrograde fluorogold immunolabeled RGC density (4623.53 ± 179.48/0.17mm²). As compared to the normal control (the ratio of β-catenin/VEGF to β-actin was set as 1 in the Sham group), the β-catenin/VEGF protein level significantly (P < 0.001) increased after retinal ischemia and when pre-ischemic intravitreous vehicle (Vehicle+IR = 1.64 ± 0.14/7.67 ± 2.57) was carried out. However, these elevations were significantly (P = 0.02) attenuated by treatment with emodin 20 μM (Emo20 + IR = 1.00 ± 0.19/1.23 ± 0.44).

Conclusions

The present results suggest that emodin might protect against retinal ischemia insulted neurons such as RGCs by significantly downregulating the upregulation of β-catenin/VEGF protein that occurs during ischemia.

Supplementary Information

Supplementary information accompanies this paper at 10.1186/s12906-020-03136-7.

Emodin in atherosclerosis prevention: Pharmacological actions and therapeutic potential

Atherosclerotic plaque formation, destabilization and eventual rupture leads to the acute cardiovascular events including myocardial infarction and stroke. Emodin (PubChem CID#3220), (1,3,8-trihydroxy-6-methylanthracene-9,10-dione) is a pharmacologically bioactive constituent isolated from the traditional Chinese medicinal herb Radix rhizoma Rhei. This molecule has anti-oxidant, anti-inflammatory, anti-proliferative, anti-apoptotic and lipid-modulating effects. Experimental studies have demonstrated that emodin attenuates and stabilizes atherosclerotic plaques. In this mini-review, we provide a summary of the pharmacological actions of emodin in regulating vascular function and atherosclerosis, highlighting the therapeutic potential of this phytochemical in patients with cardiovascular disease.

Emodin 8-O-glucoside primes macrophages more strongly than emodin aglycone via activation of phagocytic activity and TLR-2/MAPK/NF-κB signalling pathway

Emodin (Emo) is a natural plant anthraquinone derivative with a wide spectrum of pharmacological properties, including anticancer, antioxidant, and hepatoprotective activities. Glycosylation of natural anthraquinones with various sugar moieties can affect their physical, chemical, and biological functions. In this study, the potential immunomodulatory activities of Emo and its glycosylated derivative, emodin 8-O-glucoside (E8G), were evaluated and compared using murine macrophage RAW264.7 cells and human monocytic THP-1 cells. The results showed that E8G (20 μM) induced the secretion of TNF-α and IL-6 from RAW264.7 cells more effectively than unglycosylated Emo aglycone, by 4.9- and 1.6-fold, respectively, with no significant cytotoxicity in the concentration range tested (up to 20 μM). E8G (2.5-20 μM) significantly and dose-dependently induced inducible nitric oxide synthase (iNOS) expression by up to 3.2-fold compared to that of untreated control following a remarkable increase in nitric oxide (NO) production. E8G also significantly increased the expression of TLR-2 mRNA and the phosphorylation of MAPKs (JNK and p38). The activation and subsequent nuclear translocation of NF-κB was substantially enhanced upon treatment with E8G (2.5-20 μM). Moreover, E8G markedly induced macrophage-mediated phagocytosis of apoptotic Jurkat T cells. These results demonstrated that E8G far more strongly stimulates the secretion of proinflammatory cytokines, such as TNF-α and IL-6, and NO production from macrophages through upregulation of the TLR-2/MAPK/NF-κB signalling pathway than its nonglycosylated form, Emo aglycone. These results suggest for the first time that E8G may represent a novel immunomodulator, enhancing the early innate immunity.

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.

Glycoconjugation: An approach to cancer therapeutics

Cancer constitutes the second leading cause of death globally and is considered to have been responsible for an estimated 9.6 million fatalities in 2018. Although treatments against gastrointestinal tumors have recently advanced, those interventions can only be applied to a minority of patients at the time of diagnosis. Therefore, new therapeutic options are necessary for advanced stages of the disease. Glycosylation of antitumor agents, has been found to improve pharmacokinetic parameters, reduce side effects, and expand drug half-life in comparison with the parent compounds. In addition, glycosylation of therapeutic agents has been proven to be an effective strategy for their targeting tumor tissue, thereby reducing the doses of the glycodrugs administered to patients. This review focusses on the effect of the targeting properties of glycosylated antitumor agents on gastrointestinal tumors.

Anthraquinones and autophagy - Three rings to rule them all?

In order to overcome therapy resistance in cancer, scientists search in nature for novel lead structures for the development of improved chemotherapeutics. Anthraquinones belong to a class of tricyclic organic natural compounds with promising anti-cancer effects. Anthraquinone derivatives are rich in structural diversity, and exhibit pleiotropic properties, among which the modulation of autophagy seems promising in the context of overcoming cancer-therapy resistance. Among the most promising derivatives in this regard are emodin, aloe emodin, rhein, physcion, chrysophanol and altersolanol A. On the molecular level, these compounds target autophagy via different upstream pathways including the AKT/mTOR-axis and transcription of autophagy-related proteins. The role of autophagy is pro-survival as well as cell death-promoting, depending on derivatives and their cell type specificity. This review summarizes observed effects of anthraquinone derivatives on autophagy and discusses targeted pathways and crosstalks. A cumulative knowledge about this topic paves the way for further research on modes of action, and aids to find a therapeutic window of anthraquinones in cancer-therapy.

Significantly dysregulated genes in osteoarthritic labrum cells identified through gene expression profiling

The aim of the present study was to explore the molecular basis and identify significant genetic alterations in acetabular labrum cells associated with osteoarthritis (OA). Gene expression data of osteoarthritic and normal human labrum cells were downloaded from a public database and reanalyzed. Significant differentially expressed genes (DEGs) were acquired by performing a thorough analysis of microarray data between the OA acetabular labrum cells and control cells. Key genes in OA labrum cells were revealed by a combination of weighted gene co-expression network analysis (WGCNA) and protein-protein interaction (PPI) analysis. Literature mining and drug screening were further performed for these key genes. In total, 141 DEGs between OA and normal labrum cells were identified. In addition, WGCNA and PPI analysis identified 23 DEGs as key genes in the OA labrum. All the key genes were significantly downregulated in OA labrum cells and were grouped into two different WGCNA-PPI common subnetworks. Kinase insert domain receptor (KDR), CD34, cadherin 5 (CDH5), Fms related tyrosine kinase 1 (FLT1) and asporin were hub nodes in the PPI network of DEGs. These key genes were significantly enriched in functional clusters of transforming growth factor, alkaline phosphatase, bone morphogenic protein and extracellular matrix. Drug screening analysis identified several drugs targeting the key genes, including arachidonic acid, yohimbic acid and mimosine. The results of the present study indicate that the changes of FLT1, KDR, CD34 and CDH5 in acetabular labrum cells may be involved in the pathogenesis of OA and could serve as biomarkers and therapeutic targets of OA. Additionally, arachidonic acid, yohimbic acid and mimosine may act as potential drugs for OA.

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, a natural anthraquinone, suppresses liver cancer in vitro and in vivo by regulating VEGFR2 and miR-34a

The pharmacokinetic (PK) and potential effects of Emodin on liver cancer were systematically evaluated in this study. Both the intragastric administration (i.g.) and hypodermic injection (i.h.) of Emodin exhibited a strong absorption (absorption rate < 1 h) and elimination capacity (t_1/2 ≈ 2 h). The tissue distribution of Emodin after i.h. was rapid and wide. The stability of Emodin in three species of liver microsomes wasrat >human> beagle dog. These PK data provided the basis for the subsequent animal experiments. In liver cancer patient tissues, the expression of vascular endothelial growth factor (VEGF)-induced signaling pathways, including phosphorylated VEGF receptor 2 (VEGFR₂), AKT, and ERK_1/2,were simultaneously elevated, but miR-34a expression was reduced and negatively correlated with SMAD₂ and SMAD₄. Emodin inhibited the expression of SMAD_2/4 in HepG2 cells by inducing the miR-34a level. Subsequently, BALB/c nude mice received a daily subcutaneous injection of HepG2 cells with or without Emodin treatment (1 mg/kg or 10 mg/kg), and Emodin inhibited tumorigenesis and reduced the mortality rate in a dose-dependent manner. In vivo experiments showed that cell proliferation, migration, and invasion were promoted by VEGF or miR-34a signal treatment but were inhibited when combined with Emodin treatment. All these results demonstrated that Emodin inhibited tumorigenesis in liver cancer by simultaneously inhibiting the VEGFR₂-AKT-ERK_1/2signaling pathway and promoting a miR-34a-mediated signaling pathway.

Suppression of migratory and metastatic pathways via blocking VEGFR1 and VEGFR2

BACKGROUND

Vascular endothelial growth factor (VEGF) A and B are endothelial cell mitogens whose ligation to VEGFR1/VEGFR2 drives tumor angiogenesis and metastasis, and epithelial-mesenchymal transition (EMT). Blockade of these signaling axes could be obtained by disturbing the interactions between VEGFA and/or VEGFB with VEGFR1 and/or VEGFR2.

METHODS

A 14-mer peptide (VGB) that recognizes both VEGFR1 and VEGFR2 were investigated for its inhibitory effects on the VEGF-induced proliferation and migration using MTT and scratch assay, respectively. Downstream signaling pathways were also assessed by quantitative estimation of gene and protein expression using real-time PCR and immunohistochemistry (IHC).

RESULTS

We investigated the inhibitory effects of VGB on downstream mediators of metastasis, including epithelial-cadherin (E-cadherin), matrix metalloprotease-9 (MMP-9), cancer myelocytomatosis (c-Myc), and nuclear factor-κβ (NF-κβ), and migration, comprising focal adhesion kinase (FAK) and its substrate Paxilin. VGB inhibited the VEGF-induced proliferation of human umbilical vein endothelial cells (HUVECs), 4T1 and U87 cells in a time- and dose-dependent manner and migration of HUVECs. Based on IHC analyses, treatment of 4T1 mammary carcinoma tumor with VGB led to the suppression of p-AKT, p-ERK_1/2, MMP-9, NF-κβ, and activation of E-cadherin compared with PBS-treated controls. Moreover, quantitative real-time PCR analyses of VGB-treated tumors revealed the reduced expression level of FAK, Paxilin, NF-κβ, MMP-9, c-Myc, and increased expression level of E-cadherin compared to PBS-treated controls.

CONCLUSIONS

Our results demonstrated that simultaneous blockade of VEGFR1/VEGFR2 is an effective strategy to fight solid tumors by targeting a wider range of mediators involved in tumor angiogenesis, growth, and metastasis.

Highly selective anthraquinone-chalcone hybrids as potential antileukemia agents

A series of 23 novel anthraquinone-chalcone hybrids containing amide function was synthesized and structurally characterized. Sixteen compounds exerted strong cytotoxic activities against K562, Jurkat and HL-60 leukemia cell lines and significantly lower cytotoxic effects against normal MRC-5 cells, indicating very high selectivity in their anticancer action. The compounds 6g, 6u and 6v activate apoptosis in K562 cells through the extrinsic and intrinsic apoptotic pathway. The compound 6e triggered apoptosis in K562 cells only through the extrinsic apoptotic pathway. Treatment of K562 cells with each of these four compounds caused decrease in the expression levels of MMP2, MMP9, and VEGF, suggesting their anti-invasive, antimetastatic and antiangiogenic properties. The compounds 6g and 6v downregulated expression levels of miR-155 in K562 cells, while compounds 6e and 6u upregulated miR-155 levels in treated cells, in comparison with control cells. The structure-based 3-D QSAR models for 6f, 6e, 6i and 6l describe pro-apoptotic activity against caspase-3.

Rheum australe, an endangered high-value medicinal herb of North Western Himalayas: a review of its botany, ethnomedical uses, phytochemistry and pharmacology

Rheum australe (Himalayan Rhubarb) is a multipurpose, endemic and endangered medicinal herb of North Western Himalayas. It finds extensive use as a medicinal herb since antiquity in different traditional systems of medicine to cure a wide range of ailments related to the circulatory, digestive, endocrine, respiratory and skeletal systems as well as to treat various infectious diseases. The remedying properties of this plant species are ascribed to a set of diverse bioactive secondary metabolite constituents, particularly anthraquinones (emodin, chrysophanol, physcion, aloe-emodin and rhein) and stilbenoids (piceatannol, resveratrol), besides dietary flavonoids known for their putative health benefits. Recent studies demonstrate the pharmacological efficacy of some of these metabolites and/or their derivatives as lead molecules for the treatment of various human diseases. Present review comprehensively covers the literature available on R. australe from 1980 to early 2018. The review provides up-to-date information available on its botany for easy identification of the plant, and origin and historical perspective detailing its trade and commerce. Distribution, therapeutic potential in relation to traditional uses and pharmacology, phytochemistry and general biosynthesis of major chemical constituents are also discussed. Additionally, efficient and reproducible in vitro propagation studies holding vital significance in preserving the natural germplasm of the plant and for its industrial exploitation have also been highlighted. The review presents a detailed perspective for future studies to conserve and sustainably make use of this endangered plant species at a commercial scale.

Amelioration of Dalton's lymphoma-induced angiogenesis by melatonin

For tumor to grow beyond 1-2 mm³ size, tumor recruits new blood vessels referred as angiogenesis; therefore, targeting angiogenesis can be a promising strategy to suppress cancer progression. In this study, in order to develop a good angiogenesis model, we investigated effect of Dalton's lymphoma on angiogenesis and further monitored the role of melatonin on regulation of angiogenesis. To evaluate angiogenesis, endothelial cells were isolated from main thoracic aorta and cultured in vitro in the presence or absence of Dalton's lymphoma supplemented with or without melatonin to monitor their role on its proliferation and migration, a hallmark of angiogenesis. Chick chorioallantoic membrane as well as mice mesentery which allows in vivo studies of tumor angiogenesis and testing of anti-angiogenic molecules was used to validate the in vitro analysis. To further extend our understanding about the regulation of the angiogenesis, we evaluated expression of tissue inhibitor of metalloproteinases 3, vascular endothelial growth factor, vascular endothelial growth factor receptor, and fibroblast growth factor in Dalton's lymphoma cells and mesentery by semiquantitative and quantitative reverse transcription polymerase chain reaction analysis. Dalton's lymphoma ascites induced significant increase in endothelial cell proliferation, migration, and sprouting of the tertiary branching in chorioallantoic membrane and mesentery of Dalton's lymphoma-bearing mice, whereas melatonin treatment led to their inhibition in a dose-dependent manner. Semiquantitative and quantitative reverse transcription polymerase chain reaction analysis of melatonin-treated Dalton's lymphoma cells and mesentery tissue clearly demonstrated restoration of angiogenesis-related genes tissue inhibitor of metalloproteinases 3 and reduction of vascular endothelial growth factor, vascular endothelial growth factor receptor, and fibroblast growth factor messenger RNA expression. Taken together, our results strongly demonstrate that Dalton's lymphoma provides pro-angiogenic environment leading to significant increase in angiogenesis, and further melatonin treatment reduced the Dalton's lymphoma ascites-induced angiogenesis implying that Dalton's lymphoma can serve as a very good model to study angiogenesis as well as for screening of drugs that can target angiogenesis.

4-isothiocyanate-2, 2, 6, 6-tetramethyl piperidinooxyl inhibits angiogenesis by suppressing VEGFR2 and Tie2 phosphorylation

Reactive oxygen species (ROS) are involved in the signaling pathway and are triggered by angiogenic factors, including vascular endothelial growth factor and angiopoietins. 4-isothiocyanate-2, 2, 6, 6-tetramethyl piperidinooxyl (4-ISO-Tempo) is one of the nitroxides that exhibits antioxidant activity. However, the anti-angiogenic effect of 4-ISO-Tempo remains unknown. The aim of this study was to investigate the effect of 4-ISO-Tempo on tumor proliferation and angiogenesis as well as its underlying mechanisms. Our results revealed that 4-ISO-Tempo significantly inhibited the viability of neoplastic and endothelial cells. Furthermore, the effective concentration of 4-ISO-Tempo on human microvascular endothelial cell 1 (HMEC-1) was lower than that on human lung adenocarcinoma A549 and human colon cancer SW620 cells. This suggested that endothelial cells were more sensitive to 4-ISO-Tempo than tumor cells. Furthermore, we demonstrated that 4-ISO-Tempo also suppressed secretion of matrix metalloproteinase (MMP)-2 and MMP-9, and migration and tube formation of HMEC-1 cells. The mechanism is attributed to the decreasing ROS generation and further phosphorylation of vascular endothelial growth factor receptor 2 and Tie2. Our findings suggest that 4-ISO-Tempo should be investigated for its usefulness in anti-angiogenesis therapies.

Pleiotropic effects of herbs characterized with blood-activating and stasis-resolving functions on angiogenesis

Accumulative evidences have underpinned the nature candidates from Chinese medicine (CM), particularly CM served as blood activating and stasis resolving (BASR, Huoxue Huayu in Chinese) by targeting tumor-associated angiogenesis. However, recent experiment research on the therapeutic angiogenesis by BASR-CM attracts wide attention and discussion. This opinion review focused on the underlying link between two indications and anticipated that (1) BASR-CM might emphasize on a balanced multi-cytokines network interaction; (2) BASR-CM might address on the nature of diseases prior to differently affecting physiological and pathological angiogenesis; (3) BASR-CM might mainly act on perivascular cells, either promotes arteriogenesis by increasing arteriogenic factors in ischemic diseases, or simultaneously keep a quiescent vasculature to impede angiogenesis in tumor context.

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.

Emodin alleviates lung injury in rats with sepsis

BACKGROUND

Sepsis has high morbidity and mortality. The aim of this study was to investigate whether emodin, an anthraquinone derived from Chinese herb, exerts protective effects on lung injury in rat model of sepsis.

MATERIALS AND METHODS

Forty-eight male Wistar rats were randomly divided into four groups (n = 12): normal group, sham-operated group, cecal ligation and puncture (CLP) model group, and emodin-treated group. Saline or emodin (25 mg/kg) was injected intraperitoneally 0.5 h before CLP. The rats were sacrificed 48 h after CLP. Lung wet-to-dry weight ratio and pathologic changes in the lung were examined, the contents of malondialdehyde and myeloperoxidase in lung tissue were detected, serum tumor necrosis factor alpha and interleukin 6 levels were measured by enzyme-linked immunosorbent assay, and the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) was detected by Western blot analysis.

RESULTS

Compared with control group, CLP group exhibited higher wet-to-dry weight ratio and water content in the lung (P < 0.01), but these indexes were reduced and pathologic changes in the lung were relieved in the emodin-treated group. In addition, lung malondialdehyde and myeloperoxidase contents, serum levels of tumor necrosis factor alpha and interleukin 6, and phosphorylation of p38 MAPK increased in the CLP group but decreased in the emodin-treated group (P < 0.05).

CONCLUSIONS

Emodin exerts protective effects on lung injury in septic rats, which is related to the inhibition of p38 MAPK pathway and the reduction of oxidative stress and inflammation response during sepsis.

Emodin inhibits the proliferation of PC3 prostate cancer cells in vitro via the Notch signaling pathway

The aim of the present study was to examine the anticarcinogenic effects of emodin on the Notch signaling pathway and vascular endothelial growth factor (VEGF) in the PC3 androgen-independent prostate cancer cell line in vitro. The cell viability was assessed using an 3‑(4,5)‑dimethylthiahiazo(‑z‑y1)‑3,5‑di‑phenytetrazolium bromide assay. Cell apoptosis and cell cycle were detected using flow cytometry. Morphological alterations were observed using transmission electron microscopy. The mRNA and protein expression levels of Notch1, Jagged1, VEGF and bFGF were detected using reverse transcription‑quantitative polymerase chain reaction and western blotting, respectively. Laser scanning confocal microscope (LSCM) immunofluorescence analysis was performed to detect the levels of expression and the sub‑cellular localization of the Notch1 receptor protein. Growth of the PC3 cells was inhibited by emodin. Flow cytometry demonstrated that emodin induced apoptosis in the PC3 cells and arrested the cell cycle of the PC3 cells at the G2/M phase. The mRNA and protein expression of Notch1 in the PC3 cells was markedly increased, whereas the mRNA and protein expression levels of Jagged1, VEGF and bFGF were significantly decreased following exposure to emodin for 24 h. The LSCM assay revealed that the Notch1 was not only localized in the membrane and cytoplasm, but was also present in the nucleolus of the PC3 cells, and the expression of Notch1 in the nuclei gradually increased following treatment with emodin. These results demonstrated that emodin suppressed the growth of androgen‑independent prostate cancer cell lines and induced apoptosis and cell cycle arrest. The Notch signaling pathway was activated in the PC3 cells following exposure to emodin, which suggested that the Notch signaling pathway is involved in the prostate tumor‑suppressing mechanisms of emodin, the activation of which may depend on CBF1 protein in the nucleus by classic pathways. The antitumor function of emodin, attributed to the Notch signaling pathway, induced the downregulation of VEGF by suppressing tumorigenesis and angiogenesis, which indicated a novel mechanism underlying the emodin-mediated anti-prostate cancer effect.

Emodin suppresses maintenance of stemness by augmenting proteosomal degradation of epidermal growth factor receptor/epidermal growth factor receptor variant III in glioma stem cells

There is a growing body of evidence that small subpopulations of cells with stem cell-like characteristics within most solid tumors are responsible for the malignancy of aggressive cancer cells and that targeting these cells might be a good therapeutic strategy to reduce the risk of tumor relapse after therapy. Here, we examined the effects of emodin (1,3,8-trihydroxy-6-methylanthraquinone), an active component of the root and rhizome of Rheum palmatum that has several biological activities, including antitumor effects, on primary cultured glioma stem cells (GSCs). Emodin inhibited the self-renewal activity of GSCs in vitro as evidenced by neurosphere formation, limiting dilution, and soft agar clonogenic assays. Emodin inhibited the maintenance of stemness by suppressing the expression of Notch intracellular domain, nonphosphorylated β-catenin, and phosphorylated STAT3 proteins. In addition, treatment with emodin partially induced apoptosis, reduced cell invasiveness, and sensitized GSCs to ionizing radiation. Intriguingly, emodin induced proteosomal degradation of epidermal growth factor receptor (EGFR)/EGFR variant III (EGFRvIII) by interfering with the association of EGFR/EGFRvIII with heat shock protein 90, resulting in the suppression of stemness pathways. Based on these data, we propose that emodin could be considered as a potent therapeutic adjuvant that targets GSCs.

Apoptosis of Dalton's lymphoma due to in vivo treatment with emodin is associated with modulations of hydrogen peroxide metabolizing antioxidant enzymes

The evolving concept of pro-oxidative mechanism-based antitumor activity of emodin (1,3,8-trihydroxy-6-methyl anthraquinone), derived mainly from in vitro studies, needs to be defined for in vivo tumor models. The present article describes apoptosis and regression of Dalton's lymphoma (DL) in mice by emodin vis a vis modulations of hydrogen peroxide (H2O2) metabolizing antioxidant enzymes in the tumor cells in vivo. A non-toxic dose (40 mg/kg bw) of emodin, given intraperitoneally to the DL bearing mice daily up to 12th post DL transplantation day, caused a significant decline (P < 0.05) in the number of viable DL cells and could significantly increase life span of the DL mice (P < 0.01). A significant decline in Bcl2/Bax ratio consistent with the release of mitochondrial cytochrome c release in DL cells from emodin-treated DL mice suggested that emodin could induce mitochondrial pathway of apoptosis in the DL cells in vivo. Apoptosis of DL cells by emodin was further confirmed by the appearance of smaller DNA fragments on DNA ladder analysis. Over activation of both, the Cu-Zn-superoxide dismutases (SOD1) and Mn-SOD (SOD2), has been found correlated with the tumor suppression. Emodin caused significant increases in the expression and activity of SOD1 and SOD2 in the DL cells. H2O2 produced by SODs is degraded by catalase and glutathione peroxidase in the cells. Both these enzymes were observed to be declined significantly with a concomitant increment in H2O2 concentration (P < 0.01) in the DL cells from emodin-treated DL mice. It is concluded that emodin is able to induce mitochondrial pathway of apoptosis in the DL cells in vivo via reciprocal modulations of H2O2 producing and degrading antioxidant enzymes.

Synthesis and evaluation of 2-heteroaryl and 2,3-diheteroaryl-1,4-naphthoquinones that potently induce apoptosis in cancer cells

This article describes the preparation of 2-heteroaryl and 600 dpi in TIF format)??>2,3-diheteroaryl-1,4-naphthoquinones by an environmentally benign short synthetic route with the goal of finding 1,4-naphthoquinone derivatives that induce apoptosis in cancer cells.

Cancer Prevention and Therapy: Integrating Traditional Korean Medicine Into Modern Cancer Care

In spite of billions of dollars spent on cancer research each year, overall cancer incidence and cancer survival has not changed significantly in the last half century. Instead, the recent projection from the World Health Organization suggests that global cancer incidence and death is expected to double within the next decade. This requires an "out of the box" thinking approach. While traditional medicine used for thousands of years is safe and affordable, its efficacy and mechanism of action are not fully reported. Demonstrating that traditional medicine is efficacious and how it works can provide a "bed to bench" and "bench to bed" back approach toward prevention and treatment of cancer. This current review is an attempt to describe the contributions of traditional Korean medicine (TKM) to modern medicine and, in particular, cancer treatment. TKM suggests that cancer is an outcome of an imbalance of body, mind, and spirit; thus, it requires a multimodal treatment approach that involves lifestyle modification, herbal prescription, acupuncture, moxibustion, traditional exercise, and meditation to restore the balance. Old wisdoms in combination with modern science can find a new way to deal with the "emperor of all maladies."

The distinct mechanisms of the antitumor activity of emodin in different types of cancer (Review)

Emodin, a tyrosine kinase inhibitor, is a natural anthraquinone derivative found in the roots and rhizomes of numerous plants. The inhibitory effect of emodin on mammalian cell cycle modulation in specific oncogene-overexpressing cells has formed the basis for using this compound as an anticancer drug. Previous reviews have summarized the antitumor properties of emodin. However, the specific molecular mechanisms of emodin-mediated tumor inhibition have not been completely elucidated over the last 5 years. Recently, there has been great progress in the preclinical study of the anticancer mechanisms of emodin. Our recent study revealed that emodin has therapeutic effects on pancreatic cancer through various antitumor mechanisms. Notably, the therapeutic efficacy of emodin in combination with chemotherapy was found to be higher than the comparable single chemotherapeutic regime, and the combination therapy also exhibited fewer side-effects. Despite these encouraging results, further investigation is warranted as emodin has been shown to modulate one or more key regulators of cancer growth. This review provides an overview of the distinct mechanisms of anticancer action of emodin in different body systems identified over the past 5 years. These new breakthrough findings may have important implications for targeted cancer therapy and for the future clinical use of emodin.

Targeted abrogation of diverse signal transduction cascades by emodin for the treatment of inflammatory disorders and cancer

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a natural occurring anthraquinone derivative isolated from roots and barks of numerous plants, molds, and lichens. It is found as an active ingredient in different Chinese herbs including Rheum palmatum and Polygonam multiflorum, and has diuretic, vasorelaxant, anti-bacterial, anti-viral, anti-ulcerogenic, anti-inflammatory, and anti-cancer effects. The anti-inflammatory effects of emodin have been exhibited in various in vitro as well as in vivo models of inflammation including pancreatitis, arthritis, asthma, atherosclerosis and glomerulonephritis. As an anti-cancer agent, emodin has been shown to suppress the growth of various tumor cell lines including hepatocellular carcinoma, pancreatic, breast, colorectal, leukemia, and lung cancers. Emodin is a pleiotropic molecule capable of interacting with several major molecular targets including NF-κB, casein kinase II, HER2/neu, HIF-1α, AKT/mTOR, STAT3, CXCR4, topoisomerase II, p53, p21, and androgen receptors which are involved in inflammation and cancer. This review summarizes reported anti-inflammatory and anti-cancer effects of emodin, and re-emphasizes its potential therapeutic role in the treatment of inflammatory diseases and cancer.

Sparstolonin B inhibits pro-angiogenic functions and blocks cell cycle progression in endothelial cells

Sparstolonin B (SsnB) is a novel bioactive compound isolated from Sparganium stoloniferum, an herb historically used in Traditional Chinese Medicine as an anti-tumor agent. Angiogenesis, the process of new capillary formation from existing blood vessels, is dysregulated in many pathological disorders, including diabetic retinopathy, tumor growth, and atherosclerosis. In functional assays, SsnB inhibited endothelial cell tube formation (Matrigel method) and cell migration (Transwell method) in a dose-dependent manner. Microarray experiments with human umbilical vein endothelial cells (HUVECs) and human coronary artery endothelial cells (HCAECs) demonstrated differential expression of several hundred genes in response to SsnB exposure (916 and 356 genes, respectively, with fold change ≥2, p<0.05, unpaired t-test). Microarray data from both cell types showed significant overlap, including genes associated with cell proliferation and cell cycle. Flow cytometric cell cycle analysis of HUVECs treated with SsnB showed an increase of cells in the G1 phase and a decrease of cells in the S phase. Cyclin E2 (CCNE2) and Cell division cycle 6 (CDC6) are regulatory proteins that control cell cycle progression through the G1/S checkpoint. Both CCNE2 and CDC6 were downregulated in the microarray data. Real Time quantitative PCR confirmed that gene expression of CCNE2 and CDC6 in HUVECs was downregulated after SsnB exposure, to 64% and 35% of controls, respectively. The data suggest that SsnB may exert its anti-angiogenic properties in part by downregulating CCNE2 and CDC6, halting progression through the G1/S checkpoint. In the chick chorioallantoic membrane (CAM) assay, SsnB caused significant reduction in capillary length and branching number relative to the vehicle control group. Overall, SsnB caused a significant reduction in angiogenesis (ANOVA, p<0.05), demonstrating its ex vivo efficacy.

Antiangiogenic activity and pharmacogenomics of medicinal plants from traditional korean medicine

Aim. In the present study, we investigated the antiangiogenic properties of 59 plants used in traditional Korean medicine. Selected phytochemicals were investigated in more detail for their modes of action. Methods. A modified chicken-chorioallantoic-membrane (CAM) assay using quail eggs was applied to test for antiangiogenic effects of plant extracts. A molecular docking in silico approached the binding of plant constituents to the vascular endothelial growth factor receptors 1 and 2 (VEGFR1, VEGFR2). Microarray-based mRNA expression profiling was employed to correlate the 50% inhibition concentrations (IC₅₀) of a panel of 60 NCI cell lines to these phytochemicals. Results. Extracts from Acer mono leaves, Reynoutria sachalniensis fruits, Cinnamomum japonicum stems, Eurya japonica leaves, Adenophora racemosa whole plant, Caryopteris incana leaves-stems, and Schisandra chinensis stems inhibited angiogenesis more than 50% in quail eggs. Selected phytochemicals from Korean plants were analyzed in more detail using microarray-based mRNA expression profiles and molecular docking to VEGFR1 and VEGFR2. These results indicate multifactorial modes of action of these natural products. Conclusion. The antiangiogenic activity of plants used in traditional Korean medicine implicates their possible application for diseases where inhibition of blood vessel formation is desired, for example, cancer, macular degeneration, diabetic retinopathy and others.

Antiangiogenetic effects of anthranoids from Alternaria sp., an endophytic fungus in a Thai medicinal plant Erythrina variegata

Endophytic fungi are known as a prolific source for the discovery of structurally interesting and biologically active secondary metabolites, some of which are promising candidates for drug development. In the present study, three anthranoids were isolated from an Alternaria sp. endophytic fungus and evaluated for their antiangiogenic activity in a rat aortic sprouting assay, an ex vivo model of angiogenesis. Of these three compounds, altersolanol (2) was further characterized and found to show a promising activity in ex vivo, in vitro and in vivo angiogenesis asssays. Using human umbilical vein endothelial cells as an in vitro model, the angiogenic effect of 2 was found to occur via suppression of all three main functions of endothelial cells, namely proliferation, tube formation and migration.

Anticancer potential of emodin

Traditional Chinese Medicine (TCM) is widely used in clinical research due to its low toxicity, low number of side effects, and low cost. Many components of common fruits and vegetables play well-documented roles as chemopreventive or chemotherapeutic agents that suppress tumorigenesis. Anthraquinones are commonly extracted from the Polygonaceae family of plants, e.g., Rheum palmatum and Rheum officinale. Some of the major chemical components of anthraquinone and its derivatives, such as aloe-emodin, danthron, emodin, chrysophanol, physcion, and rhein, have demonstrated potential anticancer properties. This review evaluates the pharmacological effects of emodin, a major component of Aloe vera. In particular, emodin demonstrates anti-neoplastic, anti-inflammatory, anti-angiogenesis, and toxicological potential for use in pharmacology, both in vitro and in vivo. Emodin demonstrates cytotoxic effects (e.g., cell death) through the arrest of the cell cycle and the induction of apoptosis in cancer cells. The overall molecular mechanisms of emodin include cell cycle arrest, apoptosis, and the promotion of the expression of hypoxia-inducible factor 1α, glutathione S-transferase P, N-acetyltransferase, and glutathione phase I and II detoxification enzymes while inhibiting angiogenesis, invasion, migration, chemical-induced carcinogen-DNA adduct formation, HER2/neu, CKII kinase, and p34cdc2 kinase in human cancer cells. Hopefully, this summary will provide information regarding the actions of emodin in cancer cells and broaden the application potential of chemotherapy to additional cancer patients in the future.

Antitumor activity of emodin against pancreatic cancer depends on its dual role: promotion of apoptosis and suppression of angiogenesis

Background

Emodin has been showed to induce apoptosis of pancreatic cancer cells and inhibit tumor growth in our previous studies. This study was designed to investigate whether emodin could inhibit the angiogenesis of pancreatic cancer tissues and its mechanism.

Methodology/Principal Finding

In accordance with our previous study, emodin inhibited pancreatic cancer cell growth, induced apoptosis, and enhanced the anti-tumor effect of gemcitabine on pancreatic caner cells in vitro and in vivo by inhibiting the activity of NF-κB. Here, for the first time, we demonstrated that emodin inhibited tumor angiogenesis in vitro and in implanted pancreatic cancer tissues, decreased the expression of angiogenesis-associated factors (NF-κB and its regulated factors VEGF, MMP-2, MMP-9, and eNOS), and reduced eNOS phosphorylation, as evidenced by both immunohistochemistry and western blot analysis of implanted tumors. In addition, we found that emodin had no effect on VEGFR expression in vivo.

Conclusions/Significance

Our results suggested that emodin has potential anti-tumor effect on pancreatic cancer via its dual role in the promotion of apoptosis and suppression of angiogenesis, probably through regulating the expression of NF-κB and NF-κB-regulated angiogenesis-associated factors.

Emodin loaded solid lipid nanoparticles: preparation, characterization and antitumor activity studies

The objective of the present study was to prepare and characterize emodin (EMO)-loaded solid lipid nanoparticles (E-SLNs) and evaluate their antitumor activity in vitro. EMO and pharmaceutical lipid material were used to prepare E-SLNs by high pressure homogenization (HPH). Poloxamer 188 and Tween 80 were used as surfactants. The physicochemical properties of the E-SLNs were investigated by particle size analysis, zeta potential measurement, drug entrapment efficiency (EE), stability and in vitro drug release behavior. The E-SLNs showed stable particle size at 28.6 ± 3.1 nm, ideal drug EE and relative long-term physical stability after being stored for 4 months. The drug release of E-SLNs could last 72 h and exhibited a sustained profile, which made it a promising vehicle for oral drug delivery. MTT assay showed that E-SLNs could significantly enhance the in vitro cytotoxicity against human breast cancer cell line MCF-7 and MDA-MB-231 cells compared to the EMO solution, while free EMO, blank SLNs (B-SLNs) and E-SLNs all showed no significant toxicity to human mammary epithelial line MCF-10A cells. Flow cytometric analysis demonstrated that E-SLNs also showed more significant cell cycle arrest effect in MCF-7 cells compared to bulk EMO solution. Hoechst 33342 staining and Annexin V-FITC/PI double staining further confirmed that E-SLNs induced higher apoptotic rates in MCF-7 cells, indicating that cell cycle arrest and apoptosis maybe the underlying mechanism of the enhanced cytotoxicity. Taken together, it seems that HPH was a simple, available and effective method for preparing high quality E-SLNs to enhance its aqueous solubility. Moreover, these results suggest that the delivery of EMO as lipid nanoparticles maybe a promising approach for cancer therapy.