Anti-tumor effect of emodin on gynecological cancer cells

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.

The Application of Emodin Treatment on Nasopharyngeal Carcinoma Therapy

Nasopharyngeal carcinoma (NPC) is a malignancy prevailing in Taiwan, Hong Kong, Southern China, Southeast Asia, and North Africa. Although early-stage NPC responds well to the primary treatment of radio-chemotherapy, the mortality rate of advanced NPC remains high. Therefore, developing new therapies for nasopharyngeal carcinoma is an urgent task. Emodin is an anthraquinone derivative mainly found in Rheum palmatum. Emodin has been found to possess many anti-cancer functions against various types of cancers, but they are less discussed in the treatment of NPC. This review organized the different studies about the anti-NPC activity of emodin and discussed the potential and challenges of emodin treatment in NPC therapy.

Emodin treatment of papillary thyroid cancer cell lines in vitro inhibits proliferation and enhances apoptosis via downregulation of NF‑κB and its upstream TLR4 signaling

Thyroid cancer is one of the most common types of endocrine malignancy. In addition to surgical treatment, it is very important to find new treatment methods. The aim of the present study was to evaluate the effect of 1,3,8-trihydroxy-6-methylanthraquinone (emodin) on cellular NF-κB components and the upstream regulatory pathway of toll-like receptor 4 (TLR4) signaling, as well as the invasion and migration of papillary thyroid carcinoma (PTC) cells. The protein expression of NF-κB components p65 and p50 and their phosphorylated (p-) forms in the sections of PTC tissues was measured by individual immunohistochemical assays. PTC cell lines TPC-1 and IHH4 were exposed to 20 and 40 µM emodin for 24 h. The levels of the NF-κB components p65, p50, c-Rel, p-p65 and p-p50, elements in TLR4 signaling, including TLR4, MYD88 innate immune signal transduction adaptor (MyD88), interferon regulatory factor 3, AKT and MEK, and proliferative and apoptotic biomarkers, including c-Myc, cyclin D1, proliferating cell nuclear antigen, Bcl-2 and Bax, were evaluated by western blotting and immunofluorescent assays. The invasion and migration of PTC cell lines exposed to emodin were tested by plate colony and wound healing assay. Compared with hyperplasia tissue, the expression levels of NF-κB components p65 and p50, and p-p65 and p-p50 in PTC tissue were significantly increased. Treatment of PTC cell lines with emodin lead to significantly reduced levels of the aforementioned NF-κB components, accompanied by markedly downregulated TLR4 signaling. MYD 88-dependent and -independent pathways, are also significantly down-regulated. Downregulation of proliferative factors and activation of apoptotic factors were observed in the cell lines following treatment with emodin. Consequently, inhibition of the invasion and migration activities were observed in the emodin-treated PTC cells. Emodin could inhibit proliferation and promote apoptosis of PTC cells, which is dependent on the downregulation of cellular NF-κB and the TLR4 signaling pathway.

A comparative analysis of phyto-components on EGFR binding, viability, and migration in HPV positive ME180 and HPV negative C33A cervical cancer cells

A need for effective implementation of cervical cancer (CC) even in developed countries insist the urge for developing an effective drug molecule to treat CC. Previously, we showed an inverse correlation between survival of CC patients and epidermal growth factor (EGF) receptor (EGFR) levels. Newer tyrosine kinase inhibitors to treat CC are being constantly pursued. In this context, the proposed study is an attempt to perform a comparative analysis using 20 phyto-components to determine the effective lead molecule. Molecular docking was utilized to determine the comparative efficacy of 20 phyto-components in binding to EGFR. It was then validated by cell viability, mitochondrial membrane potential, apoptosis, migration, and matrix metalloproteinase (MMP-2) in human papilloma virus (HPV) positive and HPV negative CC cells using top nine phyto-components based on computational screening. Computational analysis identified nine phyto-components out of which five compounds were effective in reducing the survival, mitochondrial membrane potential, apoptosis, migration, and MMP-2 secretion. EGCG, plumbagin, quercetin, emodin, and naringenin were identified as effective molecules in attenuating CC survival, proliferation, and migration.

Dietary emodin alleviates lipopolysaccharide-induced intestinal mucosal barrier injury by regulating gut microbiota in piglets

This study was to determine the effects of dietary emodin (ED) on the intestinal mucosal barrier, nuclear factor kappa-B (NF-κB) pathways, and gut microbial flora in lipopolysaccharide (LPS)-induced piglets. Twenty-four weaned piglets were chosen and 4 treatments were created by randomly distributing piglets into CON, ED, LPS, and ED_LPS groups. Experiments were done in a 2 × 2 factorial arrangement and maintained for 21 d. Dietary treatment (a basal diet or 300 mg/kg ED) and immunological challenge (LPS or sterile saline) were 2 major factors. Intraperitoneal injections of LPS or sterilized saline were given to piglets on d 21. Six hours after the LPS challenge, all piglets were euthanized for sample collection and analysis. The results showed that piglets of the ED_LPS group had higher (P < 0.05) villus height to crypt depth ratio (VCR), and lower (P < 0.05) plasma D-lactate and diamine oxidase (DAO) than the LPS group. Furthermore, ED inhibited (P < 0.05) the decrease of glutathione peroxidase (GSH-Px) and catalase (CAT) activities and increase of malonaldehyde level (P < 0.05) in jejunal mucosa induced by LPS. The mRNA levels of pro-inflammatory cytokine genes (IL-6, IL-1β, and TNF-α) were significantly reduced (P < 0.05), and the mRNA levels of antioxidant enzyme genes (GPX-1, SOD2 and CAT), as well as protein and mRNA levels of tight junction proteins (occludin, claudin-1, and ZO-1), were also significantly increased (P < 0.05) by ED addition in LPS-induced piglets. Meanwhile, ED supplementation significantly decreased the LPS-induced protein levels of cyclooxygenase-2 and phosphorylation levels of NF-κB p65 and IκBα in jejunal mucosa. Emodin had a significant effect on the composition of gut microbial flora at various taxonomic positions as indicated by 16S RNA sequencing. The acetic acid, isobutyric acid, valeric acid, and isovaleric acid concentrations in the cecum were also increased by ED addition in pigs (P < 0.05). Furthermore, the correlation analysis revealed that some intestinal microbiota had a potential relationship with jejunal VCR, plasma D-lactate and DAO, jejunal mucosa GSH-Px and CAT activity, and cecal short-chain fatty acid concentration. These data suggest that ED is effective in alleviating LPS-induced intestinal mucosal barrier injury by modulating gut microbiota in piglets.

Anticancer action of naturally occurring emodin for the controlling of cervical cancer

One of the major causes of death on the globe is cancer. The fourth most frequent malignancy in women worldwide is cervical cancer. Several cancer patients are remaining incurable due to the emergence of medication resistance, despite notable advances in cancer research over the previous few decades. The importance of natural sources as possible therapeutic candidates may be significant. Anthraquinones are one of the many chemical families of natural products, and they stand out for their wide range of structural variations, notable biological activity, and low toxicity. A natural substance called emodin, an anthraquinone derivative, is present in the roots and rhizomes of several plants. This substance has demonstrated antineoplastic, anti-inflammatory, antiangiogenic, and antiproliferative properties. It is also capable of preventing cancer spread and can reverse cancer cells' multidrug resistance. Emodin, a broad-spectrum inhibitor of cancer cells, have anticancer properties in many different types of biological pathways. These molecular mechanisms in cancer cells include the suppression of cell growth and proliferation, deterioration of the cell cycle arrest, the start of apoptosis, antimetastasis, and antiangiogenic impact. Therefore, the aim of the present review summarised the antiproliferative and anticarcinogenic qualities of cervical cancer of emodin.

Emodin suppresses oxaliplatin-induced neuropathic pain by inhibiting COX2/NF-κB mediated spinal inflammation

Oxaliplatin (OXA) is a common chemotherapy drug for colorectal, gastric, and pancreatic cancers. The anticancer effect of OXA is often accompanied by neurotoxicity and acute and chronic neuropathy. The symptoms present as paresthesia and pain which adversely affect patients' quality of life. Herein, five consecutive intraperitoneal injections of OXA at a dose of 4 mg/kg were used to mimic chemotherapy. OXA administration induced mechanical allodynia, activated spinal astrocytes, and increased inflammatory response. To develop an effective therapeutic measure for OXA-induced neuropathic pain, emodin was intrathecally injected into OXA rats. Emodin developed an analgesic effect, as demonstrated by a significant increase in the paw withdrawal threshold of OXA rats. Moreover, emodin treatment reduced the pro-inflammatory cytokines (tumor necrosis factor-α and interleukin-1β) which upregulated in OXA rats. Furthermore, autodock data showed four hydrogen bonds were formed between emodin and cyclooxygenase-2 (COX2), and emodin treatment decreased COX2 expression in OXA rats. Cell research further proved that emodin suppressed nuclear factor κB (NF-κB)-mediated inflammatory signal and reactive oxygen species level. Taken together, emodin reduced spinal COX2/NF-κB mediated inflammatory signal and oxidative stress in the spinal cord of OXA rats which consequently relieved OXA-induced neuropathic pain.

The Invasive Species Reynoutria japonica Houtt. as a Promising Natural Agent for Cardiovascular and Digestive System Illness

Polygoni Cuspidati Rhizoma et Radix, the dry roots and stems of Reynoutria japonica Houtt (called Huzhang, HZ in Chinese), is a traditional and popular chinese medicinal herb for thousands of years. As a widely used ethnomedicine in Asia including China, Japan, and Korea, HZ can invigorate the blood, cool heat, and resolve toxicity, which is commonly used in the treatment of favus, jaundice, scald, and constipation. However, HZ is now considered an invasive plant in the United States and many European countries. Therefore, in order to take advantage of HZ and solve the problem of biological invasion, scholars around the world have carried out abundant research studies on HZ. Until now, about 110 compounds have been isolated and identified from HZ, in which anthraquinones, stilbenes, and flavonoids would be the main bioactive ingredients for its pharmacological properties, such as microcirculation improvement, myocardial protective effects, endocrine regulation, anti-atherosclerotic activity, anti-oxidant activity, anti-tumor activity, anti-viral activity, and treatment of skin inflammation, burns, and scalds. HZ has a variety of active ingredients and broad pharmacological activities. It is widely used in health products, cosmetics, and even animal husbandry feed and has no obvious toxicity. Efforts should be made to develop more products such as effective drugs, health care products, cosmetics, and agricultural and animal husbandry products to benefit mankind.

Emodin inhibits U87 glioblastoma cells migration by activating aryl hydrocarbon receptor (AhR) signaling pathway

Aryl hydrocarbon receptor (AhR) is a ligand-activated receptor to mediates the biological reactions of many environmental and natural compounds, which is highly expressed in glioblastoma. Although it has been reported that AhR agonist emodin can suppress some kinds of tumors, its inhibitory effect on glioblastoma migration and its relationship with AhR remain unclear. Based on the complexity of tumor pathogenesis and the tissue specificity of AhR, we hope can further understand the effect of emodin on glioblastoma and explore its mechanism. We found that the inhibitory effect of emodin on the migration of U87 glioblastoma cells increased with time, and the cell migration ability was inhibited by about 25% after 36 h exposure. In this process, emodin promoted the expression of the tumor suppressor IL24 by activating the AhR signaling pathway. Reducing the expression of AhR or IL24 by interfering RNA could block or relieve the inhibitory effect of emodin on the U87 cells migration, which indicates the inhibition of emodin on the migration of glioblastoma is mediated by the AhR-IL24 axis. Our data proved the AhR-IL24 signal axis is an important pathway for emodin to inhibit the migration of glioblastoma, and the AhR signaling pathway can be used as a key target to research the regulation effect and its mechanism of compounds on glioblastoma migration.

Emodin Protects Sepsis Associated Damage to the Intestinal Mucosal Barrier Through the VDR/ Nrf2 /HO-1 Pathway

Aims: Emodin is an anthraquinone extracted from Polygonum multiflorum, which has potential anti-inflammatory and anti-oxidative stress effects. However, the possible protective mechanism of emodin is unclear. The purpose of this study was to investigate the protective mechanism of emodin against cecal ligation and puncture and LPS-induced intestinal mucosal barrier injury through the VDR/ Nrf2 /HO-1 signaling pathway.

Methods: We established a mouse model of sepsis by cecal ligation and puncture (CLP), and stimulated normal intestinal epithelial cells with lipopolysaccharide (LPS). VDR in cellswas down-regulated by small interfering ribonucleic acid (siRNA) technology.Mice were perfused with VDR antagonists ZK168281 to reduce VDR expression and mRNA and protein levels of VDR and downstream molecules were detected in cells and tissue. Inflammation markers (tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6)) and oxidative stress markers (superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH)) were measured in serum and intestinal tissueby enzym-linked immunosorbent assay. The expression of VDR in intestinal tissue was detected by immunofluorescence. Histopathological changes were assessed by hematoxylin and eosin staining.

Results: In NCM460 cells and animal models, emodin increased mRNA and protein expression of VDR and its downstream molecules. In addition, emodin could inhibit the expressions of TNF-α, IL-6 and MDA in serum and tissue, and increase the levels of SOD and GSH. The protective effect of emodin was confirmed in NCM460 cells and mice, where VDR was suppressed. In addition, emodin could alleviate the histopathological damage of intestinal mucosal barrier caused by cecal ligation and puncture.

Conclusion: Emodin has a good protective effect against sepsis related intestinal mucosal barrier injury, possibly through the VDR/ Nrf2 /HO-1 pathway.

Advances in the study of emodin: an update on pharmacological properties and mechanistic basis

Rhei Radix et Rhizoma, also known as rhubarb or Da Huang, has been widely used as a spice and as traditional herbal medicine for centuries, and is currently marketed in China as the principal herbs in various prescriptions, such as Da-Huang-Zhe-Chong pills and Da-Huang-Qing-Wei pills. Emodin, a major bioactive anthraquinone derivative extracted from rhubarb, represents multiple health benefits in the treatment of a host of diseases, such as immune-inflammatory abnormality, tumor progression, bacterial or viral infections, and metabolic syndrome. Emerging evidence has made great strides in clarifying the multi-targeting therapeutic mechanisms underlying the efficacious therapeutic potential of emodin, including anti-inflammatory, immunomodulatory, anti-fibrosis, anti-tumor, anti-viral, anti-bacterial, and anti-diabetic properties. This comprehensive review aims to provide an updated summary of recent developments on these pharmacological efficacies and molecular mechanisms of emodin, with a focus on the underlying molecular targets and signaling networks. We also reviewed recent attempts to improve the pharmacokinetic properties and biological activities of emodin by structural modification and novel material-based targeted delivery. In conclusion, emodin still has great potential to become promising therapeutic options to immune and inflammation abnormality, organ fibrosis, common malignancy, pathogenic bacteria or virus infections, and endocrine disease or disorder. Scientifically addressing concerns regarding the poor bioavailability and vague molecular targets would significantly contribute to the widespread acceptance of rhubarb not only as a dietary supplement in food flavorings and colorings but also as a health-promoting TCM in the coming years.

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.

Polymeric Lipid Hybrid Nanoparticles as a Delivery System Enhance the Antitumor Effect of Emodin in Vitro and in Vivo

This study aimed to evaluate the therapeutic efficacy of Emodin-loaded polymer lipid hybrid nanoparticles (E-PLNs) for breast cancer. The size, Zeta potential, surface morphology, encapsulation efficiency, stability, in vitro drug release of E-PLNs prepared by the nanoprecipitation method were characterized. The uptake, in-vitro cytotoxicities and apoptosis of free drug, E-PLNs were investigated against MCF-7 cells. The efficacy of E-PLNs in tumor bearing nude mice has also been studied.The average particle size of the experimentally prepared E-PLNs was (122.7±1.79) nm, and the encapsulation rate was 72.8%. Compared with free Emodin (EMO), E-PLNs showed greater toxicity to MCF-7 cells by promoting the uptake of EMO, and can promote the early apoptosis of MCF-7 cells. In addition to the morphological changes of apoptotic cells, the ratio of Bax/Bcl-2 was significantly increased, which indicated that E-PLNs can induce apoptosis in MCF-7 cells to achieve anticancer effect. Finally, E-PLNs significantly inhibited tumor growth by more than 60%, which may be related to its passive targeting effect on tumor site. Our results suggest that E-PLNs have shown good anti-breast cancer effect than free EMO. Moreover, the effect of E-PLNs on MCF-7 cells is mainly related to the induction of apoptosis.

Emodin Protects Against Acute Pancreatitis-Associated Lung Injury by Inhibiting NLPR3 Inflammasome Activation via Nrf2/HO-1 Signaling

Aim

Lung injury is a common complication of acute pancreatitis (AP), which leads to the development of acute respiratory distress syndrome and causes high mortality. In the present study, we investigated the therapeutic effect of emodin on AP-induced lung injury and explored the molecular mechanisms involved.

Materials and Methods

Thirty male Sprague-Dawley rats were randomly divided into AP (n=24) and normal (n=6) groups. Rats in the AP group received a retrograde injection of 5% sodium taurocholate into the biliary-pancreatic duct and then randomly assigned to untreated, emodin, combined emodin and ML385, and dexamethasone (DEX) groups. Pancreatic and pulmonary injury was assessed using H&E staining. In in vitro study, rat alveolar epithelial cell line L2 cells were exposed to lipopolysaccharide and treated with emodin. Nrf2 siRNA pool was applied for the knockdown of Nrf2. The contents of the pro-inflammatory cytokines in the bronchoalveolar lavage fluid and lung were determined using enzyme-linked immunosorbent assay. The expressions of related mRNAs and proteins in the lung or L2 cells were detected using real-time polymerase chain reaction, Western blot, immunohistochemistry and immunofluorescence.

Key Findings

Emodin administration alleviated pancreatic and pulmonary injury of rats with AP. Emodin administration suppressed the production of proinflammatory cytokines, downregulated NLRP3, ASC and caspase-1 expressions and inhibited NF-κB nuclear accumulation in the lung. In addition, Emodin increased Nrf2 nuclear translocation and upregulated HO-1 expression. Moreover, the anti-inflammatory effect of emodin was blocked by Nrf2 inhibitor ML385.

Conclusion

Emodin effectively protects rats against AP-associated lung injury by inhibiting NLRP3 inflammasome activation via Nrf2/HO-1 signaling.

Investigation of the pharmacodynamic substances in dahuang zhechong pill that inhibit energy metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Dahuang Zhechong pill (DHZCP) is a commonly used traditional Chinese medicine for the treatment of hepatocarcinoma.

AIM OF THE STUDY

Previous studies have found that DHZCP can exert anti-hepatocarcinoma effects and reverse drug resistance by inhibiting energy metabolism. The goal of this study was to further explore the pharmacodynamic substances that inhibit energy metabolism.

METHODS

The components of DHZCP absorbed into plasma were identified by UHPLC-Q-TOF-MS/MS. The Swiss and STITCH databases were used for target collection. The DAVID database was used for pathway enrichment analysis. Cytoscape software was used for network construction. The CCK-8 method detected cell viability. Chemiluminescence was used to detect ATP levels.

RESULTS

A total of 89 components absorbed into plasma were identified by UHPLC-Q-TOF-MS/MS. Based on this, 24 potential pharmacodynamic substances were selected by network pharmacology. Among them, 11 components such as rhein can significantly inhibit ATP levels.

CONCLUSIONS

Rhein, emodin, chrysophanol, hypoxanthine, baicalein, baicalin, wogonoside, acteoside, formononetin, isoliquiritigenin, and glycyrrhizic acid were the pharmacodynamic substances responsible for inhibition of energy metabolism of DHZCP.

7-epi-Clusianone, a Multi-Targeting Natural Product with Potential Chemotherapeutic, Immune-Modulating, and Anti-Angiogenic Properties

Targeted therapies have changed the treatment of cancer, giving new hope to many patients in recent years. The shortcomings of targeted therapies including acquired resistance, limited susceptible patients, high cost, and high toxicities, have led to the necessity of combining these therapies with other targeted or chemotherapeutic treatments. Natural products are uniquely capable of synergizing with targeted and non-targeted anticancer regimens due to their ability to affect multiple cellular pathways simultaneously. Compounds which provide an additive effect to the often combined immune therapies and cytotoxic chemotherapies, are exceedingly rare. These compounds would however provide a strengthening bridge between the two treatment modalities, increasing their effectiveness and improving patient prognoses. In this study, 7-epi-clusianone was investigated for its anticancer properties. While previous studies have suggested clusianone and its conformational isomers, including 7-epi-clusianone, are chemotherapeutic, few cancer types have been demonstrated to exhibit sensitivity to these compounds and little is known about the mechanism. In this study, 7-epi-clusianone was shown to inhibit the growth of 60 cancer cell types and induce significant cell death in 25 cancer cell lines, while simultaneously modulating the immune system, inhibiting angiogenesis, and inhibiting cancer cell invasion, making it a promising lead compound for cancer drug discovery.

Hydroxyl Group Difference between Anthraquinone Derivatives Regulate Different Cell Death Pathways via Nucleo-Cytoplasmic Shuttling of p53

BACKGROUND

Despite a number of measures having been taken for cancer management, it is still the second leading cause of death worldwide. p53 is the protein principally being targeted for cancer treatment. Targeting p53 localization may be an effective strategy in chemotherapy as it controls major cell death pathways based on its cellular localization. Anthraquinones are bioactive compounds widely being considered as potential anticancer agents but their mechanism of action is yet to be explored. It has been shown that the number and position of hydroxyl groups within the different anthraquinones like Emodin and Chrysophanol reflects the number of intermolecular hydrogen bonds which affect its activity. Emodin contains an additional OH group at C-3, in comparison to Chrysophanol and may differentially regulate different cell death pathways in cancer cell.

OBJECTIVE

The present study was aimed to investigate the effect of two anthraquinones Emodin and Chrysophanol on induction of different cell death pathways in human lung cancer cells (A549 cell line) and whether single OH group difference between these compounds differentially regulate cell death pathways.

METHODS

The cytotoxic effect of Emodin and Chrysophanol was determined by the MTT assay. The expression of autophagy and apoptosis marker genes at mRNA and protein level after treatment was checked by the RT-PCR and Western Blot, respectively. For cellular localization of p53 after treatment, we performed immunofluorescence microscopy.

RESULTS

We observed that both compounds depicted a dose-dependent cytotoxic response in A549 cells which was in concurrence with the markers associated with oxidative stress such as an increase in ROS generation, decrease in MMP and DNA damage. We also observed that both compounds up-regulated the p53 expression where Emodin causes nuclear p53 localization, which leads to down-regulation in mTOR expression and induces autophagy while Chrysophanol inhibits p53 translocation into nucleus, up-regulates mTOR expression and inhibits autophagy.

CONCLUSION

From this study, it may be concluded that the structural difference of single hydroxyl group may switch the mechanism from one pathway to another which could be useful in the future to improve anticancer treatment and help in the development of new selective therapies.

Emodin promotes fibroblast apoptosis and prevents epidural fibrosis through PERK pathway in rats

Background

Laminectomy is usually classed as a common orthopedic surgery, but postoperative epidural fibrosis often leads to less-than-desirable clinical outcomes. As demonstrated by prior studies, emodin (EMO) exerts an anti-fibrotic effect. Here, we carried out investigation into the inhibitory effect created by EMO application on epidural fibrosis after laminectomy in rats.

Methods

The paper conducts a series of experiment. In vitro, we observed the effect of EMO on fibroblasts by Cell Counting Kit-8 (CCK-8) assay. Apoptosis of fibroblasts induced by EMO was detected by western blot, TUNEL assay, and flow cytometry. The results revealed that EMO was capable of inducing fibroblast apoptosis, and the proteins of PERK pathway also changed accordingly. In vivo, the effect of EMO on epidural fibrosis in 12 male Sprague-Dawley rats was observed by histological staining.

Results

CCK-8 assay indicated that EMO was effective in reducing fibroblast viability in a time- and a dose-dependent manner. TUNEL assay and flow cytometry analysis have demonstrated that the apoptotic rate of fibroblasts increased as the EMO concentration rose. Western blot analysis proved that EMO promoted the relative expression of p-perk and p-eIF2α and that the expression of its downstream proteins CHOP and GRP78 was also enhanced. The expression of apoptotic protein Bax and cleaved PARP was upregulated, whereas the expression of anti-apoptotic protein Bcl-2 was downregulated. In addition, histological and immunohistochemical analysis demonstrated that EMO functioned to inhibit epidural fibrosis and increase GRP78 expression in fibrous tissue by promoting apoptosis of fibroblasts.

Conclusions

EMO could have inhibitory effect on epidural fibrosis in a concentration-dependent manner. The potential mechanism might be through PERK signaling pathway to promote fibroblast apoptosis. It has a possibility to be taken as a novel method for the treatment of epidural fibrosis.

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.

Retracted: Emodin protects H9c2 cells against hypoxia-induced injury via regulation of miR-26a/survivin and the JAK1/STAT3 pathway

BACKGROUND/AIM

Congenital heart disease (CHD) is a catastrophic disease. Emodin possesses biological properties in protecting against some diseases. Our study investigated to explore the effects of emodin on hypoxia-stimulated cardiomyocytes, which mimicked CHD in vitro.

METHODS

H9c2 cells were stimulated with hypoxia and then the cells were treated with or without emodin, and/or transfected with miR-26a mimic, pcDNA-survivin and their corresponding negative control (NC). Cell viability and cell apoptosis were detected by Cell Counting kit-8 assay and flow cytometry, respectively. In addition, the expression of apoptotic proteins, Janus kinase 1 (JNK)/signal transducer and activator of transcription 3 (STAT3) pathway factors, and survivin were evaluated by using Western blot analysis. The expression of miR-26a was analyzed by quantitative real time polymerase chain reaction (qRT-PCR). Moreover, the target of miR-26a was verified by using a luciferase report assay.

RESULTS

Hypoxia significantly decreased cell viability and increased cell apoptosis, and the accumulated levels of cleaved caspase-3 and cleaved-caspase-9 were upregulated by hypoxia compared with the control. However, emodin administration led to the opposite result. A further result showed that emodin increased the phosphorylation of JNK/STAT3 pathway-related proteins and the pathway inhibitor AG490 impaired the protective effects of emodin on hypoxia-induced injury. In addition, emodin negatively regulated the miR-26a expression, and overexpression of miR-26a enhanced cell apoptosis and upregulated the expression of cleaved-caspase-3 and cleaved-caspase-9 compared with the NC. Moreover, emodin statistically upregulated the expression of survivin, and overexpression of miR-26a decreased the expression of survivin. The luciferase of miR-26a overexpression was decreased in the wild type of the survivin group.

CONCLUSION

Emodin protects hypoxia-induced cell injury as evidenced by increasing cell viability and decreasing apoptosis through downregulation of miR-26a as well as activation of the JNK/STAT3 pathway.

Emodin Induced SREBP1-Dependent and SREBP1-Independent Apoptosis in Hepatocellular Carcinoma Cells

Reynoutria multiflora (Thunb.) Moldenke (He Shou Wu) has been used for about 20 centuries as a Chinese medicinal herb for its activities of anticancer, anti-hyperlipidemia, and anti-aging. Previously, we found that He Shou Wu ethanol extract could induce apoptosis in hepatocellular carcinoma cells, and we also screened its active components. In this study, we investigated whether lowering lipid metabolism of emodin, a main active component in He Shou Wu, was associated with inhibitory effects in hepatocellular carcinoma cells. The correlation of apoptosis induction and lipid metabolism was investigated. The intrinsic apoptotic cell death, lipid production, and their signaling pathways were investigated in emodin-treated human hepatocellular carcinoma cells Bel-7402. The data showed that emodin triggered apoptosis in Bel-7402 cells. The mitochondrial membrane potential (ΔΨm) was reduced in emodin-treated Bel-7402 cells. We also found that emodin activated the expression of intrinsic apoptosis signaling pathway-related proteins, cleaved-caspase 9 and 3, Apaf 1, cytochrome c (CYTC), apoptosis-inducing factor, endonuclease G, Bax, and Bcl-2. Furthermore, the level of triglycerides and desaturation of fatty acids was reduced in Bel-7402 cells when exposed to emodin. Furthermore, the expression level of messenger RNA (mRNA) and protein of sterol regulatory element binding protein 1 (SREBP1) as well as its downstream signaling pathway and the synthesis and the desaturation of fatty acid metabolism-associated proteins (adenosine triphosphate citrate lyase, acetyl-CoA carboxylase alpha, fatty acid synthase (FASN), and stearoyl-CoA desaturase D) were also decreased. Notably, knock-out of SREBP1 in Bel-7402 cells was also found to induce less intrinsic apoptosis than did emodin. In conclusion, these results indicated that emodin could induce apoptosis in an SREBP1-dependent and SREBP1-independent manner in hepatocellular carcinoma cells.

A multi-targeting natural compound with growth inhibitory and anti-angiogenic properties re-sensitizes chemotherapy resistant cancer

Targeted therapies have become the focus of much of the cancer therapy research conducted in the United States. While these therapies have made vast improvements in the treatment of cancer, their results have been somewhat disappointing due to acquired resistances, high cost, and limited populations of susceptible patients. As a result, targeted therapeutics are often combined with other targeted therapeutics or chemotherapies. Compounds which target more than one cancer related pathway are rare, but have the potential to synergize multiple components of therapeutic cocktails. Natural products, as opposed to targeted therapies, typically interact with multiple cellular targets simultaneously, making them a potential source of synergistic cancer treatments. In this study, a rare natural product, deacetylnemorone, was shown to inhibit cell growth in a broad spectrum of cancer cell lines, selectively induce cell death in melanoma cells, and inhibit angiogenesis and invasion. Combined, these results demonstrate that deacetylnemorone affects multiple cancer-related targets associated with tumor growth, drug resistance, and metastasis. Thus, the multi-targeting natural product, deacetylnemorone, has the potential to enhance the efficacy of current cancer treatments as well as reduce commonly acquired treatment resistance.

Emodin suppresses angiogenesis and metastasis in anaplastic thyroid cancer by affecting TRAF6‑mediated pathways in vivo and in vitro

Emodin has been recognized to be an anti‑cancer agent against a number of types of human cancer. It was demonstrated that TNF receptor‑associated factor 6 (TRAF6) was correlated with cancer angiogenesis and metastasis. The present study confirmed the association between TRAF6 and the angiogenesis/metastasis of anaplastic thyroid cancer (ATC). The anti‑angiogenesis and metastatic effects of emodin, in addition to its molecular mechanisms in ATC, were investigated. A total of two ATC cell lines, namely 8505c and SW1736, were studied. ATC cells were implanted into nude mice to form xenografts or to establish lung metastasis models. Emodin was used to incubate ATC cells or to treat animals orally. An MTT assay was used to assess cell proliferation. A wound healing assay was employed to evaluate cell migration. ELISA analysis was used to detect the vascular endothelial growth factor (VEGF) content. Western blotting was used to determine the protein expression levels. In the in vivo study, cancer angiogenesis was assessed by micro vascular density measurement. The lung metastatic rate was the criterion for cancer metastasis. The results of the present study demonstrated that the proliferation of ATC was inhibited by emodin. The activation of the TRAF6/hypoxia inducible factor (HIF)‑1α/VEGF and TRAF6/basigin (CD147)/matrix metalloproteinase‑9 (MMP9) pathways were associated with the angiogenesis and metastasis of ATC. In a concentration‑dependent manner, emodin inhibited the TRAF6/HIF‑1α/VEGF and TRAF6/CD147/MMP9 signaling pathways to suppress angiogenesis and metastasis. In conclusion, emodin exerted anti‑angiogenic and anti‑metastatic activities in ATC by affecting TRAF6‑mediated pathways.

Gender Differences in the Hepatotoxicity and Toxicokinetics of Emodin: The Potential Mechanisms Mediated by UGT2B7 and MRP2

Emodin is a main anthraquinone compound which exists in Chinese traditional medicines including Polygonum multiflorum and Rhubarb. It is documented to have obvious liver and kidney toxicity. This study aims to (a) estimate gender differences of the hepatotoxicity and toxicokinetics in rats after oral administration of emodin (60 and 150 mg/kg/d) for a consecutive 28 days and (b) clarify relative mechanisms caused by glucuronidation and disposition. Hepatotoxicity was significantly higher in female rats than that in male rats, as evidenced by histopathological and biochemical tests. Similarly, the toxicokinetic profiles of emodin have time and gender differences, which could cause time and gender differences in hepatotoxicity. The metabolic and transcriptomics data of 55 human liver and 36 human kidney samples demonstrated that UDP-glucuronosyltransferase 2B7 (UGT2B7) was the predominant enzyme for emodin glucuronidation. A genome-wide association study (GWAS) identified that rs11726899 located within ∼50 kb of the transcript of UGT2B could significantly affect emodin metabolism. Knockdown of UGT2B7 in HepG2 cells significantly decreased emodin glucuronidation and increased cytotoxicity of emodin. The gene expression and protein levels of UGT2B7 were decreased, but those of the multidrug-resistant-protein 2 (MRP2) were increased in HepG2 cells after being treated with 50 μM emodin for 48 h. Long-term use of emodin could decrease the intrinsic clearance (CL_int, decreased by 18.5%-35.4%) values of zidovidue (UGT2B7 substrate) glucuronide in both male and female liver microsomes from rats administrated with emodin for 28 days, thus causing the accumulation of emodin. However, higher self-induced MRP2 expression and lower hepatotoxicity were observed in emodin-treated male rats compared to that in female rats. Therefore, gender differences in the hepatotoxicity and toxicokinetics of emodin are potentially mediated by the coupling of UGT2B7 and MRP2 in vivo.

Autophagy as an emerging therapy target for ovarian carcinoma

Autophagy is a conserved cellular self-digestion pathway for maintenance of homeostasis under basal and stressed conditions. Autophagy plays pivotal roles in the pathogenesis of many diseases, such as aging-related diseases, autoimmune diseases, cardiovascular diseases, and cancers. Of special note is that accumulating data suggest an intimate relationship between autophagy and ovarian carcinoma. Autophagy is well identified to act as either as a tumor-suppressor or as a tumor-promoter in ovarian carcinoma. The exact function of autophagy in ovarian carcinoma is highly dependent on the circumstances of cancer including hypoxic, nutrient-deficient, chemotherapy and so on. However, the mechanism underlying autophagy associated with ovarian carcinoma remains elusive, the precise role of autophagy in ovarian carcinoma also remains undetermined. In this review, we tried to sum up and discuss recent research achievements of autophagy in ovarian cancer. Moreover, waves of novel therapies ways for ovarian carcinoma based on the functions of autophagy were collected.

EMODIN DOWNREGULATES CELL PROLIFERATION MARKERS DURING DMBA INDUCED ORAL CARCINOGENESIS IN GOLDEN SYRIAN HAMSTERS

Background:

Cell-cycle disruption is the major characteristic features of neoplastic transformation and the status of cell-cycle regulators can thus be utilized to assess the prognostic significance in patients with cancer. The PCNA, cyclin D1, CDK4, CDK6 and survivin expression in the buccal mucosa was utilized to evaluate the Emodin efficacy on abnormal cell proliferation during 7,12-dimethylbenz(a)anthracene (DMBA) induced oral carcinogenesis in golden Syrian hamsters.

Materials and methods:

Topical application of DMBA, three times a week for 14 weeks, on the hamsters’ buccal pouches developed well differentiated squamous cell carcinoma.

Results:

Cyclin D1 and PCNA over-expression and up-regulation of CDK4, CDK6 and survivin were noticed in the buccal mucosa of hamsters treated with DMBA alone. Emodin administration (50mg/kg b.w) orally to hamsters treated with DMBA down-regulated the expression of cell proliferation markers in the buccal mucosa.

Conclusions:

The anti-cell proliferative role of Emodin is owing to its modulating efficacy on cell-cycle markers towards the tumor suppression during DMBA induced oral carcinogenesis.

Anti-neuroinflammatory Effect of Emodin in LPS-Stimulated Microglia: Involvement of AMPK/Nrf2 Activation

AMPK/Nrf2 signaling regulates multiple antioxidative factors and exerts neuroprotective effects. Emodin is one of the main bioactive components extracted from Polygonum multiflorum, a plant possessing important activities for human health and for treating a variety of diseases. This study examined whether emodin can activate AMPK/Nrf2 signaling and induce the expression of genes targeted by this pathway. In addition, the anti-neuroinflammatory properties of emodin in lipopolysaccharide (LPS)-stimulated microglia were examined. In microglia, the emodin treatment increased the levels of LKB1, CaMKII, and AMPK phosphorylation. Emodin increased the translocation and transactivity of Nrf2 and enhanced the levels of HO-1 and NQO1. In addition, the emodin-mediated expression of HO-1 and NQO1 was attenuated completely by an AMPK inhibitor (compound C). Moreover, emodin decreased dramatically the LPS-induced production of NO and PGE₂ as well as the protein expression and promoter activity of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). In addition, emodin effectively inhibited the production of pro-inflammatory cytokines, TNF-α and IL-6, and reduced the level of IκBα phosphorylation, leading to the suppression of the nuclear translocation, phosphorylation, and transactivity of NF-κB. Emodin also suppressed the LPS-stimulated activation of STATs, JNK, and p38 MAPK. The anti-inflammatory effects of emodin were reversed by transfection with Nrf-2 and HO-1 siRNA and by a co-treatment with an AMPK inhibitor. These results suggest that emodin isolated from P. multiflorum can be used as a natural anti-neuroinflammatory agent that exerts its effects by inducing HO-1 and NQO1 via AMPK/Nrf2 signaling in microglia.

Inhibitors of dihydroceramide desaturase 1: Therapeutic agents and pharmacological tools to decipher the role of dihydroceramides in cell biology

Dihydroceramide desaturase (Des1) is the last enzyme in the de novo synthesis of ceramides (Cer). It catalyzes the insertion of a double bond into dihydroceramides (dhCer) to convert them to Cer, both of which are further metabolized to more complex (dihydro) sphingolipids. For many years dhCer have received poor attention, mainly due to their supposed lack of biological activity. It was not until about ten years ago that the concept that dhCer might have regulatory roles in biology emerged for the first time. Since then, multiple publications have established that dhCer are implicated in a wide spectrum of biological processes. Physiological and pathophysiological functions of dhCer have been recently reviewed. In this review we will focus on the biochemical features of Des1 and on its inhibition by different compounds with presumably different modes of action.