Embelin Induces Apoptosis in Human Glioma Cells Through Inactivating NF-κB

Targeting inhibitor of apoptosis proteins (IAPs) enhances susceptibility of oral squamous carcinoma cells to cisplatin

PURPOSE

Oral Squamous Cell Carcinoma (OSCC) is the 6th most common cancer worldwide. It is generally aggressive and closely associated with chemoresistance and poor survival. There is accumulating evidence for the involvement of inhibitors of apoptosis proteins (IAPs), including IAP1 and XIAP, in mediating chemotherapy resistance in OSCC. Various strategies for targeting IAPs have been designed and tested in recent years and several small molecule IAP inhibitors are in clinical trials as monotherapies as well as in combination with radiotherapy and chemotherapy. The purpose of this study was to evaluate and compare the efficacy and biological activity of three IAP inhibitors both as stand-alone and sensitising agents to cisplatin in a preclinical model of squamous cell carcinoma of the tongue.

METHODS

Cisplatin-sensitive SCC4 and -resistant SCC4cisR cells were utilised in this study. Apoptosis was evaluated by flow cytometric analysis of Annexin V/Propidium Iodide-stained cells. Expression of IAP proteins was determined by western blotting and knockdown of cIAP1, livin and XIAP was conducted by transfection of cells with siRNA.

RESULTS

We establish for the first time the therapeutic efficacy of the Smac mimetic, BV6 and the XIAP inhibitor Embelin, for OSCC. Both of these IAP targeting agents synergistically enhanced cisplatin-mediated apoptotic cell death in resistant cells which was mediated in part by depletion of XIAP. In addition, knockdown of XIAP using siRNA enhanced cisplatin-mediated cell death, demonstrating the importance of targeting XIAP in this sensitisation.

CONCLUSION

These findings provide pre-clinical evidence that IAP inhibition may be a valuable therapeutic option in OSCC.

Leveraging a disulfidptosis‑related lncRNAs signature for predicting the prognosis and immunotherapy of glioma

BACKGROUND

Gliomas, a prevalent form of primary brain tumors, are linked with a high mortality rate and unfavorable prognoses. Disulfidptosis, an innovative form of programmed cell death, has received scant attention concerning disulfidptosis-related lncRNAs (DRLs). The objective of this investigation was to ascertain a prognostic signature utilizing DRLs to forecast the prognosis and treatment targets of glioma patients.

METHODS

RNA-seq data were procured from The Cancer Genome Atlas database. Disulfidptosis-related genes were compiled from prior research. An analysis of multivariate Cox regression and the least absolute selection operator was used to construct a risk model using six DRLs. The risk signature's performance was evaluated via Kaplan-Meier survival curves and receiver operating characteristic curves. Additionally, functional analysis was carried out using GO, KEGG, and single-sample GSEA to investigate the biological functions and immune infiltration. The research also evaluated tumor mutational burden, therapeutic drug sensitivity, and consensus cluster analysis. Reverse transcription quantitative PCR was conducted to validate the expression level of DRLs.

RESULTS

A prognostic signature comprising six DRLs was developed to predict the prognosis of glioma patients. High-risk patients had significantly shorter overall survival than low-risk patients. The robustness of the risk model was validated by receiver operating characteristic curves and subgroup survival analysis. Risk model was used independently as a prognostic indicator for the glioma patients. Notably, the low-risk patients displayed a substantial decrease in the immune checkpoints, the proportion of immune cells, ESTIMATE and immune score. IC50 values from the different risk groups allowed us to discern three drugs for the treatment of glioma patients. Lastly, the potential clinical significance of six DRLs was determined.

CONCLUSIONS

A novel six DRLs signature was developed to predict prognosis and may provide valuable insights for patients with glioma seeking novel immunotherapy and targeted therapy.

Modulation of the ubiquitin-proteasome system by phytochemicals: Therapeutic implications in malignancies with an emphasis on brain tumors

Regarding the multimechanistic nature of cancers, current chemo- or radiotherapies often fail to eradicate disease pathology, and frequent relapses or resistance to therapies occur. Brain malignancies, particularly glioblastomas, are difficult-to-treat cancers due to their highly malignant and multidimensional biology. Unfortunately, patients suffering from malignant tumors often experience poor prognoses and short survival periods. Thus far, significant efforts have been conducted to discover novel and more effective modalities. To that end, modulation of the ubiquitin-proteasome system (UPS) has attracted tremendous interest since it affects the homeostasis of proteins critically engaged in various cell functions, for example, cell metabolism, survival, proliferation, and differentiation. With their safe and multimodal actions, phytochemicals are among the promising therapeutic tools capable of turning the operation of various UPS elements. The present review, along with an updated outline of the role of UPS dysregulation in multiple cancers, provided a detailed discussion on the impact of phytochemicals on the UPS function in malignancies, especially brain tumors.

Embelin alleviates weaned piglets intestinal inflammation and barrier dysfunction via PCAF/NF-κB signaling pathway in intestinal epithelial cells

BACKGROUND

Intestinal barrier plays key roles in maintaining intestinal homeostasis. Inflammation damage can severely destroy the intestinal integrity of mammals. This study was conducted to investigate the protective effects of embelin and its molecular mechanisms on intestinal inflammation in a porcine model. One hundred sixty 21-day-old castrated weaned pigs (Duroc × Landrace × Yorkshire, average initial body weight was 7.05 ± 0.28 kg, equal numbers of castrated males and females) were allotted to four groups and fed with a basal diet or a basal diet containing 200, 400, or 600 mg embelin/kg for 28 d. The growth performance, intestinal inflammatory cytokines, morphology of jejunum and ileum, tight junctions in the intestinal mucosa of piglets were tested. IPEC-1 cells with overexpression of P300/CBP associating factor (PCAF) were treated with embelin, the activity of PCAF and acetylation of nuclear factor-κB (NF-κB) were analyzed to determine the effect of embelin on PCAF/NF-κB pathway in vitro.

RESULTS

The results showed that embelin decreased (P < 0.05) serum D-lactate and diamine oxidase (DAO) levels, and enhanced the expression of ZO-1, occludin and claudin-1 protein in jejunum and ileum. Moreover, the expression levels of critical inflammation molecules (interleukin-1β, interleukin-6, tumor necrosis factor-α, and NF-κB) were down-regulated (P < 0.05) by embelin in jejunal and ileal mucosa. Meanwhile, the activity of PCAF were down-regulated (P < 0.05) by embelin. Importantly, transfection of PCAF siRNAs to IPEC-1 cell decreased NF-κB activities; embelin treatment downregulated (P < 0.05) the acetylation and activities of NF-κB by 31.7%-74.6% in IPEC-1 cells with overexpression of PCAF.

CONCLUSIONS

These results suggested that embelin ameliorates intestinal inflammation in weaned pigs, which might be mediated by suppressing the PCAF/NF-κB signaling pathway.

Inhibition of IκB Kinase Is a Potential Therapeutic Strategy to Circumvent Resistance to Epidermal Growth Factor Receptor Inhibition in Triple-Negative Breast Cancer Cells

Triple-negative breast cancer (TNBC) remains as an intractable malignancy with limited therapeutic targets. High expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis of TNBC; however, EGFR targeting has failed with unfavorable clinical outcomes. Here, we performed a combinatorial screening of fifty-five protein kinase inhibitors with the EGFR inhibitor gefitinib in the TNBC cell line MDA-MB-231 and identified the IκB kinase (IKK) inhibitor IKK16 as a sensitizer of gefitinib. Cell viability and clonogenic survival assays were performed to evaluate the antiproliferative effects of the gefitinib and IKK16 (Gefitinib + IKK16) combination in TNBC cell lines. Western blot analyses were also performed to reveal the potential mode of action of this combination. In addition, next-generation sequencing (NGS) analysis was performed in Gefitinib+IKK16-treated cells. The Gefitinib+IKK16 treatment synergistically reduced cell viability and colony formation of TNBC cell lines such as HS578T, MDA-MB-231, and MDA-MB-468. This combination downregulated p-STAT3, p-AKT, p-mTOR, p-GSK3β, and p-RPS6. In addition, p-NF-κB and the total NF-κB were also regulated by this combination. Furthermore, NGS analysis revealed that NF-κB/RELA targets including CCL2, CXCL8, EDN1, IL-1β, IL-6, and SERPINE1 were further reduced and several potential tumor suppressors, such as FABP3, FADS2, FDFT1, SEMA6A, and PCK2, were synergistically induced by the Gefitinib-+IKK16 treatment. Taken together, we identified the IKK/NF-κB pathway as a potential target in combination of EGFR inhibition for treating TNBC.

Reviewing the Traditional/Modern Uses, Phytochemistry, Essential Oils/Extracts and Pharmacology of Embelia ribes Burm

OBJECTIVES

Embelia ribes Burm. (E. ribes, Myrsinaceae), also known as Vidanga in Ayurveda, has been shown to have significant therapeutic benefits on several disorders, and its main chemical bioactive constituent, embelin, has the therapeutic potential to be converted into innovative drugs, which is why it has recently received considerable interest. In the present work, we provide a higher level of comprehension, awareness, and extensive knowledge of the traditional uses, phytochemistry, and pharmacological characteristics of E. ribes throughout the last several decades (February 1965 to June 2021), emphasizing the importance of the study of essential oils extracted from E. ribes, which show a major potential for exerting antioxidant and anti-inflammatory activity.

MATERIALS AND METHODS

Google Scholar, MEDLINE, EMBASE, Scifinder, Scopus, and ScienceDirect were used to conduct a thorough literature search.

RESULTS

E. ribes is high in essential oils, alkaloids, flavonoids, steroids, and phenolics, all of which have medicinal benefits. The essential oils/extracts and isolated chemical constituents exhibited antioxidant activity, wound healing, antidiabetic, central nervous system (CNS)-related disease, antiviral, antiobesity, cardioprotective, antifungal, antibacterial, and antifertility activity, among other promising pharmacological effects.

CONCLUSION

The translation between traditional applications and modern medicine may make E. ribes a promising target for the implementation of innovative medication. To investigate the efficacy and safety profile of E. ribes, further high-quality preclinical studies using advanced methodologies are required.

Medicinal Plants in Cancer Treatment: Contribution of Nuclear Factor-Kappa B (NF-kB) Inhibitors

Nuclear factor-kappa B (NF-κB) is one of the principal inducible proteins that is a predominant transcription factor known to control the gene expression in mammals and plays a pivotal role in regulating cell signalling in the body under certain physiological and pathological conditions. In cancer cells, such as colon, breast, pancreatic, ovarian, melanoma, and lymphoma, the NF-κB pathway has been reported to be active. In cellular proliferation, promoting angiogenesis, invasion, metastasis of tumour cells and blocking apoptosis, the constitutive activity of NF-κB signalling has been reported. Therefore, immense attention has been given to developing drugs targeting NF-κB signalling pathways to treat many types of tumours. They are a desirable therapeutic target for drugs, and many studies concentrated on recognizing compounds. They may be able to reverse or standstill the growth and spread of tumours that selectively interfere with this pathway. Recently, numerous substances derived from plants have been evaluated as possible inhibitors of the NF-κB pathway. These include various compounds, such as flavonoids, lignans, diterpenes, sesquiterpenes, polyphenols, etc. A study supported by folk medicine demonstrated that plant-derived compounds could suppress NF-κB signalling. Taking this into account, the present review revealed the anticancer potential of naturally occurring compounds which have been verified both by inhibiting the NF-κB signalling and suppressing growth and spread of cancer and highlighting their mechanism of NF-κB inhibition.

Old and New Players of Inflammation and Their Relationship With Cancer Development

Pathogens or genotoxic agents continuously affect the human body. Acute inflammatory reaction induced by a non-sterile or sterile environment is triggered for the efficient elimination of insults that caused the damage. According to the insult, pathogen-associated molecular patterns, damage-associated molecular patterns, and homeostasis-altering molecular processes are released to facilitate the arrival of tissue resident and circulating cells to the injured zone to promote harmful agent elimination and tissue regeneration. However, when inflammation is maintained, a chronic phenomenon is induced, in which phagocytic cells release toxic molecules damaging the harmful agent and the surrounding healthy tissues, thereby inducing DNA lesions. In this regard, chronic inflammation has been recognized as a risk factor of cancer development by increasing the genomic instability of transformed cells and by creating an environment containing proliferation signals. Based on the cancer immunoediting concept, a rigorous and regulated inflammation process triggers participation of innate and adaptive immune responses for efficient elimination of transformed cells. When immune response does not eliminate all transformed cells, an equilibrium phase is induced. Therefore, excessive inflammation amplifies local damage caused by the continuous arrival of inflammatory/immune cells. To regulate the overstimulation of inflammatory/immune cells, a network of mechanisms that inhibit or block the cell overactivity must be activated. Transformed cells may take advantage of this process to proliferate and gradually grow until they become preponderant over the immune cells, preserving, increasing, or creating a microenvironment to evade the host immune response. In this microenvironment, tumor cells resist the attack of the effector immune cells or instruct them to sustain tumor growth and development until its clinical consequences. With tumor development, evolving, complex, and overlapping microenvironments are arising. Therefore, a deeper knowledge of cytokine, immune, and tumor cell interactions and their role in the intricated process will impact the combination of current or forthcoming therapies.

Embelin: A novel XIAP inhibitor for the prevention and treatment of chronic diseases

Chronic diseases are a serious health concern worldwide, especially in the elderly population. Most chronic diseases like cancer, cardiovascular ailments, neurodegenerative disorders, and autoimmune diseases are caused due to the abnormal functioning of multiple signaling pathways that give rise to critical anomalies in the body. Although a lot of advanced therapies are available, these have failed to entirely cure the disease due to their less efficacy. Apart from this, they have been shown to manifest disturbing side effects which hamper the patient's quality of life to the extreme. Since the last few decades, extensive studies have been done on natural herbs due to their excellent medicinal benefits. Components present in natural herbs target multiple signaling pathways involved in diseases and therefore hold high potential in the prevention and treatment of various chronic diseases. Embelin, a benzoquinone, is one such agent isolated from Embelia ribes, which has shown excellent biological activities toward several chronic ailments by upregulating a number of antioxidant enzymes (e.g., SOD, CAT, GSH, etc.), inhibiting anti-apoptotic genes (e.g., TRAIL, XIAP, survivin, etc.), modulating transcription factors (e.g., NF-κB, STAT3, etc.) blocking inflammatory biomarkers (e.g., NO, IL-1β, IL-6, TNF-α, etc.), monitoring cell cycle synchronizing genes (e.g., p53, cyclins, CDKs, etc.), and so forth. Several preclinical studies have confirmed its excellent therapeutic activities against malicious diseases like cancer, obesity, heart diseases, Alzheimer's, and so forth. This review presents an overview of embelin, its therapeutic prospective, and the molecular targets in different chronic diseases.

Role of Inflammatory Mediators, Macrophages, and Neutrophils in Glioma Maintenance and Progression: Mechanistic Understanding and Potential Therapeutic Applications

Gliomas are the most common, highly malignant, and deadliest forms of brain tumors. These intra-cranial solid tumors are comprised of both cancerous and non-cancerous cells, which contribute to tumor development, progression, and resistance to the therapeutic regimen. A variety of soluble inflammatory mediators (e.g., cytokines, chemokines, and chemotactic factors) are secreted by these cells, which help in creating an inflammatory microenvironment and contribute to the various stages of cancer development, maintenance, and progression. The major tumor infiltrating immune cells of the tumor microenvironment include TAMs and TANs, which are either recruited peripherally or present as brain-resident macrophages (microglia) and support stroma for cancer cell expansion and invasion. These cells are highly plastic in nature and can be polarized into different phenotypes depending upon different types of stimuli. During neuroinflammation, glioma cells interact with TAMs and TANs, facilitating tumor cell proliferation, survival, and migration. Targeting inflammatory mediators along with the reprogramming of TAMs and TANs could be of great importance in glioma treatment and may delay disease progression. In addition, an inhibition of the key signaling pathways such as NF-κB, JAK/STAT, MAPK, PI3K/Akt/mTOR, and TLRs, which are activated during neuroinflammation and have an oncogenic role in glioblastoma (GBM), can exert more pronounced anti-glioma effects.

Embelin downregulated cFLIP in breast cancer cell lines facilitate anti-tumor effect of IL-1β-stimulated human umbilical cord mesenchymal stem cells

Breast cancer is the leading cause of cancer-related death for women. In breast cancer treatment, targeted therapy would be more effective and less harmful than radiotherapy or systemic chemotherapy. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to induce apoptosis in cancer cells but not in normal cells. Mesenchymal stem cells have shown great therapeutic potential in cancer therapy owing to their ability of homing to tumor sites and secreting many kinds of anti-tumor proteins including TRAIL. In this study, we found that IL-1β-stimulated human umbilical cord-derived mesenchymal stem cells (hUCMSCs) enhance the expression of membrane-bound and soluble TRAIL. Cellular FADD-like IL-1β-converting enzyme inhibitory protein (cFLIP) is an important regulator in TRAIL-mediated apoptosis and relates to TRAIL resistance in cancer cells. Previous studies have shown that embelin, which is extracted from Embelia ribes, can increase the TRAIL sensitivity of cancer cells by reducing cFLIP expression. Here we have demonstrated that cFLIP_L is correlated with TRAIL-resistance and that embelin effectively downregulates cFLIP_L in breast cancer cells. Moreover, co-culture of IL-1β-stimulated hUCMSCs with embelin-treated breast cancer cells could effectively induce apoptosis in breast cancer cells. The combined effects of embelin and IL-1β-stimulated hUCMSCs may provide a new therapeutic strategy for breast cancer therapy.

NF-кB inhibition by DHMEQ: in vitro antiproliferative effects on pilocytic astrocytoma and concise review of the current literature

INTRODUCTION

Pilocytic astrocytoma (PA) is the most common brain tumor that affects the pediatric population. Even though PA is benign and treatment only involves surgery, recurrent or unresectable tumors require chemo- and radiotherapy. Besides BRAF, CDKN2A, or IDH mutations, the hyperactivation of the nuclear factor NF-κB contributes to tumor growth and survival.

METHODS

In the present study, we used publicly available data for the in silico analysis of NF-κB subunits (RELA, RELB, REL, NF-κB1, and NF-κB2) expression in PA samples. Besides, in vitro assays were performed to evaluate proliferation, migration, cell death, on the PA cell line Res286 comparing to human primary astrocytes. Sensitization to radiation therapy and temozolomide (TMZ) was also assayed.

RESULTS

Our results showed that all the members of the NF-kB family are upregulated in PA datasets compared to normal brain tissues. Moreover, DHMEQ treatment significantly reduced cell growth and motility, while sensitized cells to ionizing radiation and TMZ, as previously seen in high-grade gliomas.

CONCLUSIONS

This drug presents a potential application in clinical practice for the treatment of recurrent or inoperable PA. Moreover, its use might assist adjuvant chemotherapy and reduce irradiation doses to avoid toxicity to the surrounding tissues.

Embelin attenuates cisplatin-induced nephrotoxicity: Involving inhibition of oxidative stress and inflammation in addition with activation of Nrf-2/Ho-1 pathway

In kidneys, elevated levels of inflammatory cytokines and oxidative stress were observed in nephrotoxicity triggered by cisplatin. Embelin has the anti-inflammatory property. It also got anti-tumorigenic and antioxidant properties. In this research, we analyzed the actions of embelin on nephrotoxicity triggered by cisplatin and vital actions by which it increases antioxidant actions and corrects the inflammation after embelin administration during nephrotoxicity triggered by cisplatin. Kidney function markers including blood urea nitrogen; serum creatinine; the markers of oxidative stress like malondialdehyde (MDA), antioxidant systems like glutathione, superoxide dismutase, glutathione S-transferase, catalase, and glutathione reductase; inflammation markers like nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-1 beta (IL-1β); and the extent of nuclear factor-erythroid-2 p45-related factor-2 (Nrf2) and heme oxygenase-1 (HO-1) were determined. Histopathology studies of kidneys were also used to analyze nephrotoxicity induced by cisplatin. Treatment with embelin (25 and 50 mg/kg) upgrades the function of kidneys, by elevating antioxidant levels and reducing the MDA level in cisplatin-administered rats. Embelin treatment demonstrated a significant curtailment of oxidative stress as well as increased the activities of antioxidant enzymes, endogenously. Cisplatin upregulates cytokines (i.e., TNF-α and IL-1β) and NF-κB, and downregulates Nrf2 and HO-1. Embelin treatment also reduced the infiltration of neutrophils in the renal tubules and thus reduced the level of histological impairment. The outcome of this study implements that the signaling pathway of Nrf2/HO-1 may be the principal mechanism of embelin for protection from nephrotoxicity triggered by cisplatin, and thus, embelin diminishes oxidative stress and inflammation by impeding NF-κB. © 2019 BioFactors, 45(3):471-478, 2019.

Papaver nudicaule (Iceland poppy) alleviates lipopolysaccharide-induced inflammation through inactivating NF-κB and STAT3

BACKGROUND

Papaver nudicaule belongs to the Papaveraceae family, which is planted as an annual herbaceous species generally for ornamental purpose. Papaver rhoeas in the same family has been reported to have various pharmacological activities such as antioxidant and analgesic effects. In contrast, little is known about the pharmacological activity of Papaver nudicaule. In this study, the anti-inflammatory activity of Papaver nudicaule extracts and the action mechanisms were investigated in RAW264.7 macrophage cells.

METHODS

To investigate the anti-inflammatory activity of five cultivars of Papaver nudicaule with different flower color, samples were collected from their aerial parts at two growth stages (60 and 90 days) and their ethanol extracts were evaluated in the lipopolysaccharide (LPS)-treated RAW264.7 cells by measuring nitric oxide (NO) and prostaglandin E2 (PGE2) levels. Interleukin 1-beta (IL-1β), Interleukin-6 (IL-6) and Tumor necrosis factor alpha (TNF-α) production were also analyzed by RT-PCR and multiplex assays. Nuclear Factor-kappa-light-chain-enhancer of activated B cells (NF-κB) and Signal transducer and activator of transcription 3 (STAT3) signaling pathways were examined using western blotting and luciferase reporter assays to reveal the action mechanism of Papaver nudicaule extracts in their anti-inflammatory activity.

RESULTS

All of the Papaver nudicaule extracts were effective in reducing the LPS-induced NO, which is an important inflammatory mediator, and the extract of Papaver nudicaule with white flower collected at 90 days (NW90) was selected for further experiments because of the best effect on reducing the LPS-induced NO as well as no toxicity. NW90 lowered the LPS-induced PGE2 level and decreased the LPS-induced Nitric oxide synthase 2 (NOS2) and Cyclooxygenase 2 (COX2). In addition, NW90 reduced the LPS-induced inflammatory cytokines, IL-1β and IL-6. Furthermore, NW90 inhibited the LPS-induced activation of NF-κB and STAT3.

CONCLUSIONS

These results indicate that NW90 may restrain inflammation by inhibiting NF-κB and STAT3, suggesting the potential therapeutic properties of Papaver nudicaule against inflammatory disease.

Emerging role of plumbagin: Cytotoxic potential and pharmaceutical relevance towards cancer therapy

Plumbagin is a naphthoquinone derived yellow crystalline phytochemical. Plumbagin has a wide range of biological effects including cytotoxicity against cancer cells both in vitro and in vivo. Due to the pleiotropic nature of plumbagin, it shows the anticancer effect by targeting several molecular mechanisms including apoptosis and autophagic pathways, cell cycle arrest, anti-angiogenic pathways, anti-invasion and anti-metastasis pathways. Among many signaling pathways the key regulatory genes regulated by plumbagin are NF-kβ, STAT3, and AKT, etc. Plumbagin is also a potent inducer of ROS, suppressor of cellular glutathione, and causes DNA strand break by oxidative DNA base damages. In vivo studies suggested that plumbagin significantly reduces the tumor weight and volume in dose-dependent manner without any side effects in tested model organisms. Another exciting aspect of plumbagin is the ability to re-sensitize the chemo and radioresistant cancer cells when used in combination or alone. Nano encapsulation of plumbagin overcomes the poor water solubility and bioavailability obstacles, enhancing the pharmaceutical relevance with better therapeutic efficacy. Moreover, plumbagin can be introduced as a future phytotherapeutic anticancer drug after fully satisfied preclinical and clinical trials.

The Application of Embelin for Cancer Prevention and Therapy

Embelin is a naturally-occurring benzoquinone compound that has been shown to possess many biological properties relevant to human cancer prevention and treatment, and increasing evidence indicates that embelin may modulate various characteristic hallmarks of tumor cells. This review summarizes the information related to the various oncogenic pathways that mediate embelin-induced cell death in multiple cancer cells. The mechanisms of the action of embelin are numerous, and most of them induce apoptotic cell death that may be intrinsic or extrinsic, and modulate the NF-κB, p53, PI3K/AKT, and STAT3 signaling pathways. Embelin also induces autophagy in cancer cells; however, these autophagic cell-death mechanisms of embelin have been less reported than the apoptotic ones. Recently, several autophagy-inducing agents have been used in the treatment of different human cancers, although they require further exploration before being transferred from the bench to the clinic. Therefore, embelin could be used as a potential agent for cancer therapy.

Anti-inflammatory effects of embelin in A549 cells and human asthmatic airway epithelial tissues

OBJECTIVE

Allergic asthma is the most common type in asthma, which is defined as a chronic inflammatory disease of the lung. In this study, we investigated whether embelin (Emb), the major component of Ardisia japonica BL. (AJB), exhibits anti-inflammatory effects on allergic asthma via inhibition of NF-κB activity using A549 cells and asthmatic airway epithelial tissues.

METHODS

Inflammation was induced in A549 cells, a human airway epithelial cell line, by IL-1β (10 ng/ml) treatment for 4 h. The effects of Emb on NF-κB activity and COX-2 protein expression in inflamed airway epithelial cells and human asthmatic airway epithelial tissues were analyzed via western blot. The secretion levels of NF-κB-mediated cytokines/chemokines, including IL-4, 6, 9, 13, TNF-α and eotaxin, were measured by a multiplex assay.

RESULTS

Emb significantly blocked NF-κB activity in IL-1β-treated A549 cells and human asthmatic airway epithelial tissues. COX-2 expression was also reduced in both IL-1β-treated A549 cells and asthmatic tissues Emb application. Emb significantly reduced the secretion of IL-4, IL-6 and eotaxin in human asthmatic airway epithelial tissues by inhibiting activity of NF-κB.

CONCLUSIONS

The results of this study suggest that Emb may be used as an anti-inflammatory agent via inhibition of NF-κB and related cytokines.

Dissociable roles for histone acetyltransferases p300 and PCAF in hippocampus and perirhinal cortex-mediated object memory

The importance of histone acetylation for certain types of memory is now well established. However, the specific contributions of the various histone acetyltransferases to distinct memory functions remain to be determined; therefore, we employed selective histone acetyltransferase protein inhibitors and short-interference RNAs to evaluate the roles of CREB-binding protein (CBP), E1A-binding protein (p300) and p300/CBP-associated factor (PCAF) in hippocampus and perirhinal cortex (PRh)-mediated object memory. Rats were tested for short- (STM) and long-term memory (LTM) in the object-in-place task, which relies on the hippocampus and PRh for spatial memory and object identity processing, respectively. Selective inhibition of these histone acetyltransferases by small-interfering RNA and pharmacological inhibitors targeting the HAT domain produced dissociable effects. In the hippocampus, CBP or p300 inhibition impaired long-term but not short-term object memory, while inhibition of PCAF impaired memory at both delays. In PRh, HAT inhibition did not impair STM, and only CBP and PCAF inhibition disrupted LTM; p300 inhibition had no effects. Messenger RNA analyses revealed findings consistent with the pattern of behavioral effects, as all three enzymes were upregulated in the hippocampus (dentate gyrus) following learning, whereas only CBP and PCAF were upregulated in PRh. These results demonstrate, for the first time, the necessity of histone acetyltransferase activity for PRh-mediated object memory and indicate that the specific mnemonic roles of distinctive histone acetyltransferases can be dissociated according to specific brain regions and memory timeframe.

Morusin induces apoptosis by regulating expression of Bax and Survivin in human breast cancer cells

Morusin which has been isolated from the root bark of Morus alba L. (Moraceae) has previously demonstrated anticancer activity in various types of cancer cells such as hepatocellular carcinoma, glioma and prostate cancer. However, the effect of morusin on breast cancer cells remains unclear. In the present study, the potential of morusin as an anti-cancer agent in breast cancer was investigated. The results of the present study revealed that the treatment of morusin induced cell death in various human breast cancer cell lines, but exhibited little effect on normal human breast epithelial cells. In Annexin V-propidium iodide double staining assays, morusin significantly increased apoptosis in a dose-dependent manner in human breast cancer cells. The apoptosis marker proteins cleaved caspase 3 and 9 were consistently upregulated following treatment of cells with morusin in a time- and dose-dependent manner. Furthermore, morusin was demonstrated to modulate the expression of the anti-apoptotic protein Survivin and pro-apoptotic protein B-cell lymphoma 2-associated-x protein (Bax) in human breast cancer cells. These results indicate that morusin induces apoptosis by suppressing Survivin and inducing Bax proteins, suggesting that morusin is a potentially effective therapeutic agent for the treatment of patients with breast cancer.

Plant Derived Phytocompound, Embelin in CNS Disorders: A Systematic Review

A Central nervous system (CNS) disease is the one which affects either the spinal cord or brain and causing neurological or psychiatric complications. During the nineteenth century, modern medicines have occupied the therapy for many ailments and are widely used these days. Herbal medicines have often maintained popularity for historical and cultural reasons and also considered safer as they originate from natural sources. Embelin is a plant-based benzoquinone which is the major active constituent of the fruits of Embelia ribes Burm. It is an Indo-Malaysian species, extensively used in various traditional medicine systems for treating various diseases. Several natural products including quinone derivatives, which are considered to possess better safety and efficacy profile, are known for their CNS related activity. The bright orange hydroxybenzoquinone embelin-rich fruits of E. ribes have become popular in ethnomedicine. The present systematic review summarizes the effects of embelin on central nervous system and related diseases. A PRISMA model for systematic review was utilized for search. Various electronic databases such as Pubmed, Springer, Scopus, ScienceDirect, and Google Scholar were searched between January 2000 and February 2016. Based on the search criteria for the literature, 13 qualified articles were selected and discussed in this review. The results of the report showed that there is a lack of translational research and not a single study was found in human. This report gives embelin a further way to be explored in clinical trials for its safety and efficacy.

The 1,4 benzoquinone-featured 5-lipoxygenase inhibitor RF-Id induces apoptotic death through downregulation of IAPs in human glioblastoma cells

Background

Embelin is a potent dual inhibitor of 5-lipoxigenase (5-LOX) and microsomal prostaglandin E2 synthase (mPGES)-1 that suppresses proliferation of human glioma cells and induces apoptosis by inhibiting XIAP and NF-κB signaling pathway. Synthetic structural modification yielded the derivative 3-((decahydronaphthalen-6-yl)methyl)-2,5-dihydroxycyclohexa-2,5-diene-1,4-dione (RF-Id), an embelin constrained analogue, with improved efficiency against 5-LOX in human neutrophils and anti-inflammatory activity in vivo. Taking into account that lipoxygenase (LOX) metabolites, from arachidonic acid and linoleic acid, have been implicated in tumor progression, here, we determined whether RF-Id was able to hinder glioblastoma (GBM) cancer cell growth and the related mechanisms.

Methods

U87MG and LN229 cells were plated in 96-wells and treated with increasing concentrations of RF-Id. Cell viability was evaluated by MTT assay. The effects of the compounds on cell cycle, apoptosis, oxidative stress and autophagy were assessed by flow cytometry (FACS). The mode of action was confirmed by Taqman apoptosis array and evaluating caspase cascade and NFκB pathway by western blotting technique.

Results

Here, we found that RF-Id induced a stronger inhibition of GBM cell growth than treatment with embelin. Flow cytometry analysis showed that RF-Id induced about 30 % apoptosis and a slight increase of autophagy after 72 h on U87-MG cells. Moreover, the compound induced an increase in the percentage of cells in G2 and S phase that was paralleled by an increase of p21 and p27 expression but no significant changes of the mitochondrial membrane potential; array analysis showed a significant upregulation of CASP8 and a downregulation of IAP family and NFκB genes in cells treated with RF-Id. RF-Id induced a significant cleavage of caspases 8, 9, 3 and 7, blocked c-IAP2/XIAP interaction by inducing XIAP degradation and inhibited NFκB pathway.

Conclusions

RF-Id induced a caspase-dependent apoptosis in GBM cells by inhibiting IAP family proteins and NFκB pathway and represents a promising lead compound for designing a new class of anti-cancer drugs with multiple targets.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0440-x) contains supplementary material, which is available to authorized users.

Morusin Induces TRAIL Sensitization by Regulating EGFR and DR5 in Human Glioblastoma Cells

Glioblastoma is one of the most malignant primary tumors, and the prognosis for glioblastoma patients remains poor. Tumor-necrosis-factor-related apoptosis-inducing ligand (TRAIL) is considered a promising anticancer agent due to its remarkable ability to selectively kill tumor cells. However, since many cancers are resistant to TRAIL, strategies to overcome resistance are required for the successful use of TRAIL in the clinic. In the present study, the potential of morusin as a TRAIL sensitizer in human glioblastoma cells was evaluated. Treatment with TRAIL or morusin alone showed weak cytotoxicity in human glioblastoma cells. However, combination treatment of TRAIL with morusin synergistically decreased cell viability and increased apoptosis compared with single treatment. Morusin induced expression of death receptor 5 (DR5), but not DR4 or decoy receptors (DcR1 and DcR2). Furthermore, morusin significantly decreased anti-apoptotic molecules survivin and XIAP. In addition, morusin reduced expression of EGFR and PDFGR as well as phosphorylation of STAT3, possibly mediating down-regulation of survivin and XIAP. Together these results suggest that morusin enhances TRAIL sensitivity in human glioblastoma cells through regulating expression of DR5 and EGFR. Therefore, the combination treatment of TRAIL and morusin may be a new therapeutic strategy for malignant glioma patients.

The X-Linked Inhibitor of Apoptosis Protein Inhibitor Embelin Suppresses Inflammation and Bone Erosion in Collagen Antibody Induced Arthritis Mice

Objective. To investigate the effect of Embelin, an inhibitor of X-Linked Inhibitor of Apoptosis Protein (XIAP), on inflammation and bone erosion in a collagen antibody induced arthritis (CAIA) in mice. Methods. Four groups of mice (n = 6 per group) were allocated: CAIA untreated mice, CAIA treated with Prednisolone (10 mg/kg/day), CAIA treated with low dose Embelin (30 mg/kg/day), and CAIA treated with high dose Embelin (50 mg/kg/day). Joint inflammation was evaluated using clinical paw score and histological assessments. Bone erosion was assessed using micro-CT, tartrate resistant acid phosphatase (TRAP) staining, and serum carboxy-terminal collagen crosslinks (CTX-1) ELISA. Immunohistochemistry was used to detect XIAP protein. TUNEL was performed to identify apoptotic cells. Results. Low dose, but not high dose Embelin, suppressed inflammation as reflected by lower paw scores (P < 0.05) and lower histological scores for inflammation. Low dose Embelin reduced serum CTX-1 (P < 0.05) and demonstrated lower histological score and TRAP counting, and slightly higher bone volume as compared to CAIA untreated mice. XIAP expression was not reduced but TUNEL positive cells were more abundant in Embelin treated CAIA mice. Conclusion. Low dose Embelin suppressed inflammation and serum CTX-1 in CAIA mice, indicating a potential use for Embelin to treat pathological bone loss.

Oleuropein induced apoptosis in HeLa cells via a mitochondrial apoptotic cascade associated with activation of the c-Jun NH2-terminal kinase

Oleuropein could inhibit growth and/or induce apoptosis in several cancer cell lines. In this study, we investigate how oleuropein strongly induces apoptotic cell death in HeLa human cervical carcinoma cells. Oleuropein induced HeLa cells apoptosis as demonstrated by induction of a sub-G(1) peak in flow cytometry and apoptosis-related morphological changes observed by fluorescence microscopy after being stained by Hoechst 33324. The results also showed that 150 - 200 μM oleuropein&ndash;treated HeLa cells were arrested at the G(2)/M phase. Western blot analysis revealed that the phosphorylated ATF-2, c-Jun NH(2)-terminal kinase (JNK) protein, p53, p21, Bax, and cytochrome c protein in the cytoplasm significantly increased in a dose-dependent manner after treatment of oleuropein for 24 h. Additionally, increasing levels of Bax in response to JNK/SPAK signaling, which formed mitochondrial membrane channels, accounted for releasing of cytochrome c and activation of caspase-9 and -3. SP600125 (20 μM), a JNK(1/2) inhibitor, markedly suppressed the formation of apoptotic bodies and JNK activation induced by oleuropein at 200 μM. Thus, oleuropein-induced apoptosis was activated by the JNK/SPAK signal pathway. The result shows that oleuropein holds promise as a potential chemotherapeutic agent for the treatment of HeLa cells.

The role of NF-κB in the pathogenesis of glioma

Activation of NF-κB affects multiple aspects of cancer biology including cell survival and resistance to treatment. Glioblastoma (GBM) is the most common primary malignant tumor of the brain in adults and is resistant to treatment. Recent studies have reported that NF-κB activation in GBM is widespread and have elucidated the underlying regulatory mechanisms. EGFR gene amplification and mutation are among the key genetic alterations in GBM, and aberrant EGFR signaling is a key activator of NF-κB in GBM. In this review we discuss the evidence for activation of NF-κB in GBM and the key signaling pathways involved. Substantial evidence suggests a role for NF-κB in the pathogenesis of GBM and its resistance to treatment, indicating that NF-κB pathways may be useful targets for treatment.

AT-406, an IAP inhibitor, activates apoptosis and induces radiosensitization of normoxic and hypoxic cervical cancer cells

IAP antagonists increased the antitumor efficacy of X-irradiation in some types of cancers, but their effects on hypoxic cancer cells remain unclarified. We aims to investigate the radiosensitizing effect of an IAP inhibitor AT-406 on cervical cancer cell lines under both normoxia and hypoxia conditions. Hela and Siha cells were treated to investigate the effects of drug administration on cell proliferation, apoptosis, and radiosensitivity. Western blot analysis was used to determine the role of AT-406 in inhibition of IAPs. The pathway of apoptosis was characterized by caspases activity assay. AT-406 potently sensitized Hela cells but not Siha cells to radiation under normoxia. Notably, the radiosensitizing effect of AT-406 on hypoxic cells was more evident than on normoxic cells in both cell lines. Further mechanism studies by western blot showed that under normoxia AT-406 decreased the level of cIAP1 in Hela cells in a dose-dependent manner; while additional downregulation of XIAP expression was induced by AT-406 treatment under hypoxia in both cell lines. Finally, AT-406 works on both extrinsic death receptor and intrinsic mitochondrial apoptosis pathways to activate apoptosis. Totally, AT-406 acts as a strong radiosensitizer in human cervical cancer cells, especially in hypoxic condition.

Nanomicellar carriers for targeted delivery of anticancer agents

Clinical application of anticancer drugs is limited by problems such as low water solubility, lack of tissue-specificity and toxicity. Formulation development represents an important approach to these problems. Among the many delivery systems studied, polymeric micelles have gained considerable attention owing to ease in preparation, small sizes (10-100 nm), and ability to solubilize water-insoluble anticancer drugs and accumulate specifically at the tumors. This article provides a brief review of several promising micellar systems and their applications in tumor therapy. The emphasis is placed on the discussion of the authors' recent work on several nanomicellar systems that have both a delivery function and antitumor activity, named dual-function drug carriers.

Activation of p38/JNK pathway is responsible for embelin induced apoptosis in lung cancer cells: transitional role of reactive oxygen species

The natural product embelin has been demonstrated to possess a wide range of therapeutic properties, however, the mechanisms by which it exerts anticancer effects are not yet clear. By monitoring the molecular changes associated during early apoptotic phase, we have identified the crucial role of oxidative stress induced MAP kinase signalling as a predominant mechanism for its anticancer effects. Treatment of A549 lung cancer cells with embelin resulted in the enhancement of phospho-p38 and phospho-JNK levels as early as 4h. Pretreatment of cells with specific inhibitors of p38 (PD169316) and JNK (SP600125) abrogated embelin-induced caspase-3 activation. Studies employing embelin in the presence or absence of specific MAP kinase inhibitors indicated that the observed changes in phosphorylation levels of p38, JNK and ERK 1/2 are solely due to embelin and not because of cross-talk between MAP kinases. Reactive oxygen species (ROS) play a crucial role in embelin induced alterations in MAP kinase phosphorylation and apoptosis as pretreatment of cells with FeTMPyP mitigated this effect. The observed changes are not due to the inhibitory effect of embelin on XIAP as cells treated with SMAC-N7-Ant peptide, a specific inhibitor of XIAP’s BIR3 domain did not mimic embelin induced apoptotic effects. The findings of the present study clearly indicate the crucial role of p38 and JNK pathways in embelin induced apoptosis and provide us with new clues for improving its therapeutic efficacy.