Brevilin A promotes oxidative stress and induces mitochondrial apoptosis in U87 glioblastoma cells

Pro-Oxidant Auranofin and Glutathione-Depleting Combination Unveils Synergistic Lethality in Glioblastoma Cells with Aberrant Epidermal Growth Factor Receptor Expression

Glioblastoma (GBM) is the most prevalent and advanced malignant primary brain tumor in adults. GBM frequently harbors epidermal growth factor receptor (EGFR) wild-type (EGFRwt) gene amplification and/or EGFRvIII activating mutation. EGFR-driven GBM relies on the thioredoxin (Trx) and/or glutathione (GSH) antioxidant systems to withstand the excessive production of reactive oxygen species (ROS). The impact of EGFRwt or EGFRvIII overexpression on the response to a Trx/GSH co-targeting strategy is unknown. In this study, we investigated Trx/GSH co-targeting in the context of EGFR overexpression in GBM. Auranofin is a thioredoxin reductase (TrxR) inhibitor, FDA-approved for rheumatoid arthritis. L-buthionine-sulfoximine (L-BSO) inhibits GSH synthesis by targeting the glutamate-cysteine ligase catalytic (GCLC) enzyme subunit. We analyzed the mechanisms of cytotoxicity of auranofin and the interaction between auranofin and L-BSO in U87MG, U87/EGFRwt, and U87/EGFRvIII GBM isogenic GBM cell lines. ROS-dependent effects were assessed using the antioxidant N-acetylsteine. We show that auranofin decreased TrxR1 activity and increased ROS. Auranofin decreased cell vitality and colony formation and increased protein polyubiquitination through ROS-dependent mechanisms, suggesting the role of ROS in auranofin-induced cytotoxicity in the three cell lines. ROS-dependent PARP-1 cleavage was associated with EGFRvIII downregulation in U87/EGFRvIII cells. Remarkably, the auranofin and L-BSO combination induced the significant depletion of intracellular GSH and synergistic cytotoxicity regardless of EGFR overexpression. Nevertheless, molecular mechanisms associated with cytotoxicity were modulated to a different extent among the three cell lines. U87/EGFRvIII exhibited the most prominent ROS increase, P-AKT(Ser-473), and AKT decrease along with drastic EGFRvIII downregulation. U87/EGFRwt and U87/EGFRvIII displayed lower basal intracellular GSH levels and synergistic ROS-dependent DNA damage compared to U87MG cells. Our study provides evidence for ROS-dependent synergistic cytotoxicity of auranofin and L-BSO combination in GBM in vitro. Unraveling the sensitivity of EGFR-overexpressing cells to auranofin alone, and synergistic auranofin and L-BSO combination, supports the rationale to repurpose this promising pro-oxidant treatment strategy in GBM.

Mechanistic prediction and validation of Brevilin A Therapeutic effects in Lung Cancer

BACKGROUND

Traditional Chinese medicine (TCM) has been found widespread application in neoplasm treatment, yielding promising therapeutic candidates. Previous studies have revealed the anti-cancer properties of Brevilin A, a naturally occurring sesquiterpene lactone derived from Centipeda minima (L.) A.Br. (C. minima), a TCM herb, specifically against lung cancer. However, the underlying mechanisms of its effects remain elusive. This study employs network pharmacology and experimental analyses to unravel the molecular mechanisms of Brevilin A in lung cancer.

METHODS

The Batman-TCM, Swiss Target Prediction, Pharmmapper, SuperPred, and BindingDB databases were screened to identify Brevilin A targets. Lung cancer-related targets were sourced from GEO, Genecards, OMIM, TTD, and Drugbank databases. Utilizing Cytoscape software, a protein-protein interaction (PPI) network was established. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene set enrichment analysis (GSEA), and gene-pathway correlation analysis were conducted using R software. To validate network pharmacology results, molecular docking, molecular dynamics simulations, and in vitro experiments were performed.

RESULTS

We identified 599 Brevilin A-associated targets and 3864 lung cancer-related targets, with 155 overlapping genes considered as candidate targets for Brevilin A against lung cancer. The PPI network highlighted STAT3, TNF, HIF1A, PTEN, ESR1, and MTOR as potential therapeutic targets. GO and KEGG analyses revealed 2893 enriched GO terms and 157 enriched KEGG pathways, including the PI3K-Akt signaling pathway, FoxO signaling pathway, and HIF-1 signaling pathway. GSEA demonstrated a close association between hub genes and lung cancer. Gene-pathway correlation analysis indicated significant associations between hub genes and the cellular response to hypoxia pathway. Molecular docking and dynamics simulations confirmed Brevilin A's interaction with PTEN and HIF1A, respectively. In vitro experiments demonstrated Brevilin A-induced dose- and time-dependent cell death in A549 cells. Notably, Brevilin A treatment significantly reduced HIF-1α mRNA expression while increasing PTEN mRNA levels.

CONCLUSIONS

This study demonstrates that Brevilin A exerts anti-cancer effects in treating lung cancer through a multi-target and multi-pathway manner, with the HIF pathway potentially being involved. These results lay a theoretical foundation for the prospective clinical application of Brevilin A.

A review of natural products and small-molecule therapeutics acting on central nervous system malignancies: Approaches for drug development, targeting pathways, clinical trials, and challenges

In 2021, the World Health Organization released the fifth edition of the central nervous system (CNS) tumor classification. This classification uses histopathology and molecular pathogenesis to group tumors into more biologically and molecularly defined entities. The prognosis of brain cancer, particularly malignant tumors, has remained poor worldwide, approximately 308,102 new cases of brain and other CNS tumors were diagnosed in the year 2020, with an estimated 251,329 deaths. The cost and time-consuming nature of studies to find new anticancer agents makes it necessary to have well-designed studies. In the present study, the pathways that can be targeted for drug development are discussed in detail. Some of the important cellular origins, signaling, and pathways involved in the efficacy of bioactive molecules against CNS tumorigenesis or progression, as well as prognosis and common approaches for treatment of different types of brain tumors, are reviewed. Moreover, different study tools, including cell lines, in vitro, in vivo, and clinical trial challenges, are discussed. In addition, in this article, natural products as one of the most important sources for finding new chemotherapeutics were reviewed and over 700 reported molecules with efficacy against CNS cancer cells are gathered and classified according to their structure. Based on the clinical trials that have been registered, very few of these natural or semi-synthetic derivatives have been studied in humans. The review can help researchers understand the involved mechanisms and design new goal-oriented studies for drug development against CNS malignancies.

Sesquiterpene lactones as emerging biomolecules to cease cancer by targeting apoptosis

Apoptosis is a programmed cell death comprising two signaling cascades including the intrinsic and extrinsic pathways. This process has been shown to be involved in the therapy response of different cancer types, making it an effective target for treating cancer. Cancer has been considered a challenging issue in global health. Cancer cells possess six biological characteristics during their developmental process known as cancer hallmarks. Hallmarks of cancer include continuous growth signals, unlimited proliferation, resistance to proliferation inhibitors, apoptosis escaping, active angiogenesis, and metastasis. Sesquiterpene lactones are one of the large and diverse groups of planet-derived phytochemicals that can be used as sources for a variety of drugs. Some sesquiterpene lactones possess many biological activities such as anti-inflammatory, anti-viral, anti-microbial, anti-malarial, anticancer, anti-diabetic, and analgesic. This review article briefly overviews the intrinsic and extrinsic pathways of apoptosis and the interactions between the modulators of both pathways. Also, the present review summarizes the potential effects of sesquiterpene lactones on different modulators of the intrinsic and extrinsic pathways of apoptosis in a variety of cancer cell lines and animal models. The main purpose of the present review is to give a clear picture of the current knowledge about the pro-apoptotic effects of sesquiterpene lactones on various cancers to provide future direction in cancer therapeutics.

NADPH Oxidase 3: Beyond the Inner Ear

Reactive oxygen species (ROS) were formerly known as mere byproducts of metabolism with damaging effects on cellular structures. The discovery and description of NADPH oxidases (Nox) as a whole enzyme family that only produce this harmful group of molecules was surprising. After intensive research, seven Nox isoforms were discovered, described and extensively studied. Among them, the NADPH oxidase 3 is the perhaps most underrated Nox isoform, since it was firstly discovered in the inner ear. This stigma of Nox3 as "being only expressed in the inner ear" was also used by me several times. Therefore, the question arose whether this sentence is still valid or even usable. To this end, this review solely focuses on Nox3 and summarizes its discovery, the structural components, the activating and regulating factors, the expression in cells, tissues and organs, as well as the beneficial and detrimental effects of Nox3-mediated ROS production on body functions. Furthermore, the involvement of Nox3-derived ROS in diseases progression and, accordingly, as a potential target for disease treatment, will be discussed.

Cellular stress responses as modulators of drug cytotoxicity in pharmacotherapy of glioblastoma

Despite the extensive efforts to find effective therapeutic strategies, glioblastoma (GBM) remains a therapeutic challenge with dismal prognosis of survival. Over the last decade the role of stress responses in GBM therapy has gained a great deal of attention, since depending on the duration and intensity of these cellular programs they can be cytoprotective or promote cancer cell death. As such, initiation of the UPR, autophagy or oxidative stress may either impede or facilitate drug-mediated cell killing. In this review, we summarize the mechanisms that regulate ER stress, autophagy, and oxidative stress during GBM development and progression to later discuss the involvement of these stress pathways in the response to different treatments. We also discuss how a precise understanding of the molecular mechanisms regulating stress responses evoked by different pharmacological agents could decisively contribute to the design of novel and more effective combinational treatments against brain malignancies.

Brevilin A exerts anti-colorectal cancer effects and potently inhibits STAT3 signaling invitro

Colorectal cancer (CRC) is the third most common cause of cancer-related morbidity worldwide, with an estimated of 1.85 million new cases and 850,000 deaths every year. Nevertheless, the current treatment regimens for CRC have many disadvantages, including toxicities and off-targeted side effects. STAT3 (signal transducer and activator of transcription 3) has been considered as a promising molecular target for CRC therapy. Brevilin A, a sesquiterpene lactone compound rich in Centipedae Herba has potent anticancer effects in nasopharyngeal, prostate and breast cancer cells by inhibiting the STAT3 signaling. However, the anti-CRC effect of brevilin A and the underlying mechanism of action have not been fully elucidated. In this study, we aimed to investigate the involvement of STAT3 signaling in the anti-CRC action of brevilin A. Here, HCT-116 and CT26 cell models were used to investigate the anti-CRC effects of brevilin A in vitro. HCT-116 cells overespressing with STAT3 were used to evaluate the involvement of STAT3 signaling in the anti-CRC effect of brevilin A. Screening of 49 phosphorylated tyrosine kinases in the HCT-116 cells after brevilin A treatment was performed by using the human phospho-receptor tyrosine kinase (phospho-RTK) array. Results showed that brevilin A inhibited cell proliferation and cell viability, induced apoptosis, reduced cell migration and invasion, inhibited angiogenesis, lowered the protein expression levels of phospho-Src (Tyr416), phospho-JAK2 (Y1007/1008) and phospho-STAT3 (Tyr705), and inhibited STAT3 activation and nuclear localization. Brevilin A also significantly reduced the protein expression levels of STAT3 target genes, such as MMP-2, VEGF and Bcl-xL. More importantly, over-activation of STAT3 diminished brevilin A's effects on cell viability. All these results suggest that brevilin A exerts potent anti-CRC effects, at least in part, by inhibiting STAT3 signaling. Our findings provide a strong pharmacological basis for the future exploration and development of brevilin A as a novel STAT3-targeting phytotherapeutic agent for CRC treatment.

Brevilin A inhibits RANKL-induced osteoclast differentiation and bone resorption

Brevilin A (BA) is the primary component of Centipeda minima, which is widely used in Chinese traditional medicine. The anti-inflammatory and anti-tumor properties of BA have been established; however, its function in bone metabolism is not well understood. This study revealed that concentrations of BA below 1.0 µM did not inhibit the proliferation of bone marrow macrophages but did impede the differentiation and bone resorption activity of osteoclasts. Furthermore, BA suppressed the expression of osteoclast-specific genes Mmp9, Acp5, Dc-stamp, Ctsk, and Atp6v0d2. In addition, mTOR, ERK, and NFATc1 activation in bone marrow macrophages were suppressed by BA. As a whole, BA blocks the mTOR and ERK signaling pathways, which is responsible for the development and activity of osteoclasts, and the resorption of bone.

Brevilin A Inhibits VEGF-Induced Angiogenesis through ROS-Dependent Mitochondrial Dysfunction

Brevilin A (BA), a sesquiterpene lactone isolated from Centipeda minima herb, has been identified to exhibit potent anticancer activity. However, the potential pharmacological effect and mechanism of BA in regulating endothelial cell (EC) angiogenesis, a key event in tumor growth, is poorly understood. In this study, BA was shown to significantly prevent vascular endothelial growth factor (VEGF) induced EC angiogenic capacities in vitro, ex vivo, and in vivo. Subsequent functional assays revealed that BA dose dependently inhibited VEGF-stimulated survival, proliferation, migration, and triggered apoptosis activity in human umbilical vein endothelial cells (HUVECs), as well as suppressed the expression of antiapoptotic protein Bcl-2, increased the expression of proapoptotic protein caspase-3 and Bax, and suppressed PI3K/AKT pathway. Meanwhile, BA was also able to depolarize mitochondrial membranal permeability (MMP), accelerate mitochondrial superoxide accumulation, induce intracellular reactive oxygen species (ROS) production, and decreased intracellular glutathione (GSH) in HUVECs. Furthermore, both mitochondria-specific superoxide scavenger Mito-TEMPOL and broad-spectrum antioxidant N-acetyl-cysteine (NAC) dramatically abolished BA-induced mitochondrial dysfunction and mitochondrial ROS production, causing the reversion of PI3K/AKT pathway and repression of apoptosis, eventually correcting the impaired endothelial behavior in survival, growth, migration, and angiogenesis. Collectively, our data for the first time identified a new mechanism for antiangiogenic effect of BA in vascular EC, one that is based on the regulation of mitochondrial-dependent ROS overproduction.

Promising anticancer activities and mechanisms of action of active compounds from the medicinal herb Centipeda minima (L.) A. Braun & Asch

BACKGROUND

Centipeda minima (L.) A. Braun & Asch (C. minima) has been used as a traditional Chinese herbal medicine to treat multiple diseases, including sinusitis, rhinitis, headache, and allergy. To date, the anticancer properties of C. minima have drawn considerable attention owing to the anticancer potential of C. minima extracts, the identification of active components, and the elucidation of underlying molecular mechanisms. However, the anticancer properties and significance of active components in C. minima have rarely been summarized.

PURPOSE

This review presents a comprehensive summary of the anticancer properties exhibited by active components of C. minima.

METHODS

An extensive search for published articles on the anticancer activities and active components of C. minima was performed using Web of Science, PubMed, Science Direct, and Google Scholar.

RESULTS

C. minima extracts exhibited both anticancer and chemosensitizing effects. Phytochemical studies have identified the active anticancer components of C. minima extracts. Sesquiterpene lactones, such as 6-O-angeloylplenolin (6-OAP, or brevilin A) and arnicolide D, have similar structures and anticancer mechanisms. As the most abundant sesquiterpene lactone in C. minima, 6-OAP exhibits anticancer activities mainly by targeting Skp1-Cullin1-F-box protein (SCF) E3 ubiquitin ligase and signal transducers and activators of transcription 3 (STAT3). Clinical trials have assessed the potential of 6-OAP in patients with vertex balding and alopecia areata, given its effect on JAK-STATs signaling. Chlorogenic acid, a representative organic acid in C. minima, reportedly possesses anticancer potential and inhibits tumor growth by affecting tumor microenvironment and has been approved for phase II clinical trials in patients with glioma in China.

CONCLUSION

In the present review, we highlight intriguing anticancer properties mediated by active compounds isolated from C. minima extracts, particularly sesquiterpene lactones, which might provide clues for developing novel anticancer drugs. Relevant clinical trials on chlorogenic acid and 6-OAP can promote anticancer clinical applications. Therefore, it is worth comprehensively elucidating underlying anticancer mechanisms and conducting clinical trials on C. minima and its active components.

Role of STAT3 in the pathogenesis of nasopharyngeal carcinoma and its significance in anticancer therapy

Nasopharyngeal carcinoma (NPC) is a type of head and neck tumor with noticeable regional and ethnic differences. It is associated with Epstein-Barr virus infection and has a tendency for local and distant metastasis. NPC is also highly sensitive to radiotherapy and chemotherapy. Over 70% of patients present with locoregionally advanced disease, and distant metastasis is the primary reason for treatment failure. A signal transducer and activator of transcription 3 (STAT3) promotes NPC oncogenesis through mechanisms within cancerous cells and their interactions with the tumor microenvironment, which is critical in the initiation, progression, and metastasis of NPC. Further, p-STAT3 is strongly associated with advanced NPC. Recent research on STAT3 has focused on its expression at the center of various oncogenic pathways. Here, we discuss the role of STAT3 in NPC and its potential therapeutic inhibitors and analogs for the treatment and control of NPC.

Centipeda minima: An update on its phytochemistry, pharmacology and safety

ETHNOPHARMACOLOGICAL RELEVANCE

Centipeda minima (CM), the dried whole plant of Centipeda minima (L.) A. Braun and Aschers, has been used as a traditional Chinese medicinal herb for thousands of years for the treatments of rhinitis, sinusitis, cough and asthmatic diseases. This review aimed to evaluate the therapeutic potential of CM by summarizing its phytochemistry, pharmacology, clinical application and safety.

METHODS

This review summarizes the published studies on CM in the Chinese Pharmacopoeia and literature databases including PubMed, Web of Science, Baidu Scholar, Wiley and China Knowledge Resource Integrated Database (CNKI), as well as the research articles on the phytochemistry, pharmacology, clinical application and safety of CM.

RESULTS

A total of 191 compounds have been isolated and identified from CM, including terpenes, flavonoids, sterols, phenols, organic acids and volatile oils. In addition, the pharmacological effects of CM, such as anti-cancer, anti-inflammatory and anti-bacterial activities, have also been evaluated by both in vitro and in vivo studies. The signaling pathways and mechanisms of action underlying the anti-cancer effects of CM have been revealed. Clinical applications of CM mainly include rhinitis and sinusitis, gynecological inflammation, cough, as well as asthma.

CONCLUSION

CM is a medicinal herb that possesses many therapeutic effects. Cutting-edge technology and system biology could provide us a more comprehensive understanding of the therapeutic effects, constituting components and toxicity of CM, which are the prerequisites for its translation into therapeutics for various disease treatments.

Brevilin A Ameliorates Acute Lung Injury and Inflammation Through Inhibition of NF-κB Signaling via Targeting IKKα/β

Acute lung injury (ALI) is life-threatening disease characterized by uncontrolled inflammatory response. IKKα/β, the key kinases in the activation of NF-κB pathway, are implicated in inflammatory pulmonary injury, and represent attractive targets for ALI therapy. Brevilin A (BVA) is a sesquiterpene lactone from Centipeda minima, a Chinese herb used to treat inflammatory diseases. This study aims to investigate the inhibition of BVA on ALI, with focus on clarifying the molecular mechanisms involved in BVA-mediated anti-inflammatory activity in macrophages. Briefly, BVA significantly inhibited the production of NO and PGE₂ by suppressing iNOS and COX2 expression, and suppressed the mRNA expression of IL-1β, IL-6, and TNFα in LPS/IFNγ-stimulated RAW264.7 macrophages. The anti-inflammatory activity of BVA was further confirmed in LPS/IFNγ-stimulated BMDMs and TNFα/IFNγ-exposed RAW264.7 cells. In vivo, BVA effectively attenuated LPS-induced lung damage, inflammatory infiltration, and production of pro-inflammatory cytokines, including MPO, IL-1β, IL-6, TNFα, and PGE₂. Mechanistically, BVA could covalently bind to the cysteine 114 of IKKα/β, and effectively inhibiting the activity and function of IKKα/β, thereby resulting in the suppression of phosphorylation and degradation of IκBα and the subsequent activation of NF-κB signaling. Furthermore, pretreatment of DTT, a thiol ligand donor, significantly abolished BVA-mediated effects in LPS/IFNγ-stimulated RAW264.7 cells, suggesting the crucial role of the electrophilic α, β-unsaturated ketone of BVA on its anti-inflammatory activity. These results suggest that BVA ameliorates ALI through inhibition of NF-κB signaling via covalently targeting IKKα/β, raising the possibility that BVA could be effective in the treatment of ALI and other diseases harboring aberrant NF-κB signaling.

Synthetic and Naturally Occurring Heterocyclic Anticancer Compounds with Multiple Biological Targets

Cancer is a complex group of diseases initiated by abnormal cell division with the potential of spreading to other parts of the body. The advancement in the discoveries of omics and bio- and cheminformatics has led to the identification of drugs inhibiting putative targets including vascular endothelial growth factor (VEGF) family receptors, fibroblast growth factors (FGF), platelet derived growth factors (PDGF), epidermal growth factor (EGF), thymidine phosphorylase (TP), and neuropeptide Y4 (NY4), amongst others. Drug resistance, systemic toxicity, and drug ineffectiveness for various cancer chemo-treatments are widespread. Due to this, efficient therapeutic agents targeting two or more of the putative targets in different cancer cells are proposed as cutting edge treatments. Heterocyclic compounds, both synthetic and natural products, have, however, contributed immensely to chemotherapeutics for treatments of various diseases, but little is known about such compounds and their multimodal anticancer properties. A compendium of heterocyclic synthetic and natural product multitarget anticancer compounds, their IC50, and biological targets of inhibition are therefore presented in this review.

Lectin isolated from Abelmoschus esculentus induces caspase mediated apoptosis in human U87 glioblastoma cell lines and modulates the expression of circadian clock genes

Lectins are a cluster of proteins which are capable of recognizing and binding to glycoconjugates and are extensively found in plants, animals, fungi and bacteria. Plant-derived lectins have been gaining importance over the years due to their innumerable biological activities and also have the added possibility of being compatible to the human system while simultaneously exhibiting properties like antimicrobial and antitumor activities. Abelmoschus esculentus (AE) commonly known as okra is a vegetable with medicinal properties. AE extracts are used to treat disorders such as constipation, microbial infection, urine retention, hypoglycemia and inflammation in humans. Previous studies showed that lectin isolated from AE exhibited anti inflammatory, anti nociceptive, anticancer, antioxidant and hemagglutinating activities. However, the antitumor effect of the lectin derived from this plant against neural cancer cells still remains unexplored. Glioblastoma is a malignant tumor of the nervous system. Treatment options for patients afflicted by glioblastoma is limited to surgical resection, preceded by radiation therapy and followed by chemotherapy. Hence it would be of interest to identify novel bio molecules with ability to selectively target glioblastoma with minimum side effects. In this aspect, lectins from vegetables that are commonly used as food products could offer a promising lead as anticancer molecules. The present study proves the anti-proliferative effect of lectin isolated from AE on human U87 glioma cells. MTT assay showed significant concentration dependent cytotoxic activity and the IC₅₀ value was calculated as 21 μg/ml. Further, annexin V/FITC staining by FACS, the expression of caspase 3 and 7 and the circadian genes clock and Bmal1 using RT-PCR and the generation of intracellular ROS, cell cycle analysis by FACS revealed the ability of AEL to induce effective apoptosis.

Epigenetics of Triple-negative breast cancer via natural compounds

Triple-negative breast cancer (TNBC) is a highly resistant, lethal, and metastatic sub-division of breast carcinoma, characterized by the deficiency of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). In women, TNBC shows a higher aggressive behavior with poor patient prognosis and a higher recurrence rate during reproductive age. TNBC is defined by the presence of epithelial-to-mesenchymal-transition (EMT), which shows a significant role in cancer progression. At the epigenetic level, TNBC is characterized by epigenetic signatures, such as DNA methylation, histone remodeling, and a host of miRNA, MiR-193, LncRNA, HIF-2α, eEF2K, LIN9/NEK2, IMP3, LISCH7/TGF-β1, GD3s and KLK12 mediated regulation. These modifications either are silenced or activate the necessary genes that are prevalent in TNBC. The review is based on epigenetic mediated mechanistic changes in TNBC. Furthermore, Thymoquinone (TQ), Regorafenib, Fangjihuangqi decoction, Saikosaponin A, and Huaier, etc., are potent antitumor natural compounds extensively reported in the literature. Further, the review emphasizes the role of these natural compounds in TNBC and their possible epigenetic targets, which can be utilized as a potential therapeutic strategy in treatment of TNBC.

Brevilin A inhibits NLRP3 inflammasome activation in vivo and in vitro by acting on the upstream of NLRP3-induced ASC oligomerization

Brevilin A (BA), is a natural biologically active ingredient derived from Centipeda minima with several reports of anti-cancer, while its anti-inflammatory activity is rarely reported. Current studies have found the dysregulated activation of NLRP3 inflammasome cause a variety of inflammatory diseases. Targeting the NLRP3 inflammasome contributes to the treatment of NLRP3-induced diseases. Here, we found that BA significantly attenuates the activation of caspase-1 and the subsequent secretion of the interleukin-1β (IL-1β) in mouse macrophages and human THP-1 cells, showing the inhibitory effect of BA on the NLRP3 inflammasome activation. Moreover, BA specifically inhibits NLRs inflammasomes activation triggered by multi-stimuli, but it has no effect on the AIM2 inflammasome activation, indicating that BA is a specific inhibitor of the NLRs inflammasomes. Research on the mechanism found BA inhibits NLRP3 inflammasome activation by blocking the upstream of ASC oligomerization. Importantly, in vivo experiments showed that BA markedly reduces the secretion of IL-1β to suppress NLRP3 inflammasome in the LPS-induced inflammation and MSU-challenged peritonitis model. In conclusion, our experiments show that BA is an effective NLRP3 inflammasome inhibitor and can be regarded as a drug candidate for NLRP3 inflammasome-driven diseases.

Anti-fibrotic effects of brevilin A in hepatic fibrosis via inhibiting the STAT3 signaling pathway

Hepatic fibrosis is a chronic liver disease characterized by the accumulation of extracellular matrix (ECM). Activation of hepatic stellate cells (HSCs) after repetitive liver damage is a key event in hepatic fibrogenesis. As part of ongoing research projects to identify pharmacologically effective natural products, the phytochemical investigation of a MeOH extract of Centipeda minima led to the isolation of a sesquiterpene lactone, brevilin A, which was explored to elucidate potential anti-fibrotic effects by reversing HSC activation. First, we observed that transforming growth factor (TGF)-β1 treatment significantly increased the expression levels of HSC activation marker, α-smooth muscle actin (α-SMA), and ECM protein such as collagen and fibronectin. Then, we demonstrated that brevilin A reversed the TGF-β1-induced increase in protein and mRNA expression levels of α-SMA and collagen. To investigate the underlying molecular mechanism of brevilin A, we evaluated the effects of brevilin A on the STAT3 signaling pathway. STAT3 phosphorylation, increased by TGF-β1 treatment, was strongly inhibited by brevilin A; the expression levels of fibronectin and connective tissue growth factor were also significantly decreased by brevilin A. The present study indicated that brevilin A has a preventive and therapeutic potential against hepatic fibrosis.

Synthesis and Evaluation of Novel Anticancer Compounds Derived from the Natural Product Brevilin A

Cancer is the second leading cause of death globally, responsible for an estimated 9.6 million deaths in 2018, and this burden continues to increase. Therefore, there is a clear and urgent need for novel drugs with increased efficacy for the treatment of different cancers. Previous research has demonstrated that brevilin A (BA) exerts anticancer activity in various cancers, including human multiple myeloma, breast cancer, lung cancer, and colon carcinoma, suggesting the anticancer potential present in the chemical scaffold of BA. Here, we designed and synthesized a small library of 12 novel BA derivatives and evaluated the biological anticancer effects of the compounds in various cancer cell lines. The results of this structure-activity relationship study demonstrated that BA derivatives BA-9 and BA-10 possessed significantly improved anticancer activity toward lung, colon, and breast cancer cell lines. BA-9 and BA-10 could more effectively reduce cancer cell viability and induce DNA damage, cell-cycle arrest, and apoptosis when compared with BA. Our findings represent a significant step forward in the development of novel anticancer entities.

Brevilin A, a Natural Sesquiterpene Lactone Inhibited the Growth of Triple-Negative Breast Cancer Cells via Akt/mTOR and STAT3 Signaling Pathways

Purpose

Triple-negative breast cancer (TNBC) is a a breast cancer subtype characterized by a lack of estrogen receptor, progesterone receptor and human epidermal growth receptor 2 and is associated with poorer prognoses when compared to other breast cancers. Thus, novel anti-cancer agents with high efficacy are urgently needed. Brevilin A (BA), a natural sesquiterpene lactone, has been reported to exhibit anti-cancer effects. However, the effects of BA on TNBC have not yet been demonstrated. In this study, we investigated the anti-TNBC effects and the underlying mechanism of BA, in vitro and in vivo.

Methods

Two TNBC cell lines and a xenograft mouse model were employed to assess the effects of BA. Cell viability was detected by MTT assay. Cell cycle status and apoptosis were evaluated by flow cytometry. Cell migration was measured by wound-healing assay. Protein expression was measured by Western blotting analysis. The in vivo anti-cancer activity of BA was assessed in orthotopic tumor xenograft mice.

Results

BA significantly inhibited the growth of TNBC cells in a dose- and time-dependent manner via induction of cell cycle arrest at G2/M phase arrest and apoptosis. BA also inhibited tumor cell migration. BA significantly downregulated the expression of Akt, mTOR, Stat3 and their phosphorylation, and thus inhibiting the activation of the Akt/mTOR and STAT3 signaling pathways. Furthermore, oral administration of BA at 25 or 50 mg/kg leads to significant inhibition of tumor growth and proliferation in tumor xenograft model mice.

Conclusion

BA significantly inhibited the growth and migration of TNBC cells, and induced cell cycle arrest and apoptosis. These inhibitory effects were associated with the suppression of the Akt/mTOR and Stat3 signal pathways. Based on our findings, BA possesses a promising candidate for development as an anti-cancer therapeutic drug against TNBC.

Anti-cancer Activity of Centipeda minima Extract in Triple Negative Breast Cancer via Inhibition of AKT, NF-κB, and STAT3 Signaling Pathways

Breast cancer is the most commonly diagnosed cancer in females worldwide. Estimates from the World Health Organization (WHO) International Agency for Research on Cancer, suggest that globally, there were around 2.1 million new breast cancer cases and 627,000 deaths due to breast cancer in 2018. Among the subtypes of breast cancer, triple negative breast cancer (TNBC) is the most aggressive and carries the poorest prognosis, largest recurrence, and lowest survival rate. Major treatment options for TNBC patients are mainly constrained to chemotherapy, which can be accompanied by severe side effects. Therefore, development of novel and effective anti-cancer drugs for the treatment of TNBC are urgently required. Centipeda minima is a well-known traditional Chinese herbal medicine that has historically been used to treat rhinitis, sinusitis, relieve pain, and reduce swelling. Recent studies have shown that Centipeda minima exhibited efficacy against certain cancers, however, to date, no studies have been conducted on its effects in breast cancer. Here, we aimed to investigate the anti-cancer activity of the total extract of Centipeda minima (CME), and its underlying mechanism, in TNBC. In MDA-MB-231, we found that CME could significantly reduce cell viability and proliferation, induce apoptosis and inhibit cancer cell migration and invasion, in a dose and time-dependent manner. We showed that CME may potentially act via inhibition of multiple signaling pathways, including the EGFR, PI3K/AKT/mTOR, NF-κB, and STAT3 pathways. Treatment with CME also led to in vitro downregulation of MMP-9 activity and inhibition of metastasis. Further, we demonstrated that CME could significantly reduce tumor burden in MDA-MB-231 xenograft mice, without any appreciable side effects. Based on our findings, CME is a promising candidate for development as a therapeutic with high efficacy against TNBC.

Punicic Acid Inhibits Glioblastoma Migration and Proliferation via the PI3K/AKT1/mTOR Signaling Pathway

BACKGROUND

Punicic Acid (PA) is a polyunsaturated fatty acid that accounts for approximately 70%- 80% of Pomegranate Seed Oil (PSO). PA possesses strong antioxidant, anti-inflammatory, anti-atherogenic effects, and anti-tumorigenic properties. Pomegranate extracts have been shown to have anticancer activity in many studies. However, there is no evidence for the effect of PSO on T98 glioblastoma cells. Therefore, the present study was the first to investigate the mechanisms induced by PA on T98 cells, which is one of the major compounds extracted from PSO.

METHODS

The effects of PA on cell viability; oxidative stress; and migration, proliferation, and apoptosis at the IC50 dose were studied.

RESULTS

The proliferation and migration were inhibited in the treated group compared to the non-treated group by 9.85µl/ml PA. The difference was statistically significant (***p<0.001). Furthermore, PA-induced apoptosis in the T98 glioblastoma cells compared to non-treated group and the difference was statistically significant (***p<0.001). Apoptosis was determined via immunocytochemistry staining of caspase-3, caspase-9 and TUNEL methods. Apoptosis was checked by flow cytometry (using caspase 3 methods) and Scanning Electron Microscopy Analysis. We also investigated the potential signaling pathway underlying this apoptotic effect. The immunocytochemical stainings of PI3K/ Akt-1/ mTOR-1 demonstrated that Akt-1 staining was increased with PA treatment similar to mTOR-1 and PI3K staining (***p<0.001). These increases were statistically significant compared to the non-treated group.

CONCLUSION

PA exhibited exceptional abilities as an anticancer agent against GBM cells. The use of punicic acid in combination with other drugs used in the treatment of glioblastoma may increase the efficacy of the treatment. This study provided a basis for future investigation of its use in preclinical and clinical studies.

Brevilin A induces ROS-dependent apoptosis and suppresses STAT3 activation by direct binding in human lung cancer cells

Sesquiterpene lactones have been shown to be promising leads for anticancer drug development. Brevilin A (BLN-A), a sesquiterpene lactone compound of Centipeda minima has been shown to exhibit anticancer effects against various cancer cells. However, the anticancer mechanism and cellular targets of BLN-A remain elusive. Here in this study, BLN-A inhibits proliferation and induces cell morphological changes in A549 and NCI-H1650 non-small cell lung cancer cells in a dose-dependent manner. Moreover, BLN-A increased ROS generation and bax/bcl-2 ratio while decreased intracellular glutathione (GSH), and mitochondrial membrane potential which resulted in induction of apoptosis as evident by annexin-V/FITC staining, caspase-3 activation and PARP cleavage. Supplementation of cells with NAC (ROS Scavenger) effectively protected the cells from BLN-A-induced apoptosis. Finally, BLN-A inhibited constitutive as well as IL-6- and EGF-induced STAT3 activation at Tyr705. Using molecular docking and SPR analyses, we found that BLN-A directly binds with STAT3 and thereby inhibits its activation. Knocking down of STAT3 by stable transfection with shRNA suppressed growth and augmented cytotoxicity of BLN-A, indicating the key role of STAT3 in BLN-A-mediated apoptosis. Cumulative findings suggest that BLN-A is a promising lead structure for developing it into a potent STAT3 inhibitor and therapeutic agent against NSCLC as well.

Brevilin A Inhibits STAT3 Signaling and Induces ROS-Dependent Apoptosis, Mitochondrial Stress and Endoplasmic Reticulum Stress in MCF-7 Breast Cancer Cells

Purpose

Breast cancer is the most common malignancy among women across the globe. Despite concerted efforts to improve the prevailing treatment modalities, the overall prognosis of breast cancer remains unsatisfactory. Recently, antiproliferative activity of Brevilin A (Brv-A), a sesquiterpene lactone compound of Centipeda minima, has been unveiled in various cancer types. Here, we have explored anticancer activity of Brv-A in MCF-7 breast carcinoma cells by targeting various pathways.

Materials and Methods

Cell proliferation rate was determined by CCK-8 and clonogenic assay. Cellular morphological changes were observed under phase contrast microscope while calcein-AM and PI was used for live/dead assay. Cell cycle assay was performed by flow cytometry. Apoptotic cell percentage was determined by Hoechst 33258 staining and flow cytometric analysis. ROS generation and mitochondrial membrane potential were measured using commercially available kits while protein expression was measured by Western blotting.

Results

In our study, Brv-A exerted antiproliferative effect through mitotic arrest at G₂/M phase of cell cycle and induced apoptosis in MCF-7 cells in a dose-dependent manner. Induction of apoptosis by Brv-A was found to be associated with ROS generation by targeting NOX2 and NOX3, mitochondrial dysfunction (MMP dissipation and Bcl-2 family proteins modulation), DNA fragmentation, JNK and p38 MAPK activation, endoplasmic reticulum (ER) stress by increasing Bip/GRP78, ATF4 and CHOP protein expressions and inhibition of STAT3 activation via decreased phosphorylation of JAK2 and SRC. Pretreatment of NAC, a ROS scavenger, partially reversed the aforesaid cellular events indicating ROS generation as the primary event to modulate cellular targets for induction of apoptosis. Besides, Brv-A has also been documented for inhibition of cell migration via decrease in COX-2 and MMP-2 expression.

Conclusion

Taken together, Brv-A induces G₂/M phase arrest, ROS-dependent apoptosis, ER stress, mitochondrial dysfunction and inhibits STAT3 activation in MCF-7 cells signifying it to be one of the potential anticancer therapeutics in future.

Baicalein, as a Prooxidant, Triggers Mitochondrial Apoptosis in MCF-7 Human Breast Cancer Cells Through Mobilization of Intracellular Copper and Reactive Oxygen Species Generation

Background

Baicalein, a natural flavonoid derived from traditional Chinese herb Scutellaria baicalensis Georg (known as Huang Qin in Chinese), has been reported to exhibit notable antitumor activity in various cancer cells, including breast cancer. However, the detailed mechanisms underlying its induced apoptosis as a prooxidant in breast cancer cells are still unknown.

Materials and methods

In this study, we investigated the effect of endogenous copper on cytotoxic activity of baicalin against human breast cancer MCF-7 cells in vitro.

Results

Baicalein could remarkably reduce the cell viability in both dose- and time-dependent manners in MCF-7 cells but with lower cytotoxic effects on normal breast epithelial cells, MCF-10A. Such cell death could be prevented by pretreatment with Cu (I)-specific chelator neocuproine (Neo) and reactive oxygen species (ROS) scavengers. Meanwhile, baicalein could induce MCF-7 cell morphological changes, promote apoptotic cell death and increase the apoptotic cell number. Moreover, DCHF-DA staining, flow cytometry and Western blotting analyses proved that baicalein triggered the mitochondrial-dependent apoptotic pathway, as indicated by enhancement the level of intracellular ROS, disruption of mitochondrial membrane potential (ΔΨm), downregulation of anti-apoptotic protein Bcl-2, upregulation of pro-apoptotic protein Bax, release of cytochrome C and activation of caspase-9 and caspase-3 in MCF-7 cells. The pretreatment with Neo remarkably weakened these effects of baicalein. Furthermore, we confirmed that the prooxidant action of baicalein involved the direct production of hydroxyl radicals through redox recycling of copper ions.

Conclusion

These findings suggested that baicalein, acting as a prooxidant, could trigger apoptosis in MCF-7 cells occurs via the ROS-mediated intrinsic mitochondria-dependent pathway.

Brevilin A Induces Cell Cycle Arrest and Apoptosis in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is one of the most common malignant cancers in Southeast Asia and Southern China. Centipeda minima extract (CME) had previously demonstrated anti-cancer effects in human NPC. Brevilin A, a sesquiterpene lactone isolated from C. minima, has been reported to exhibit biological activities. In this study, we investigated its anti-NPC effect and further explored its molecular mechanisms. The effects of brevilin A were tested in the NPC cell lines CNE-1, CNE-2, SUNE-1, HONE1, and C666-1. Effects of brevilin A on cell viability were determined by MTT assay, and cell cycle and apoptosis were detected by flow cytometry. The molecular mechanism of cell cycle regulation and apoptosis were investigated via Western blot. Results showed that brevilin A inhibited NPC cell viability in a concentration- and time-dependent manner. Brevilin A induced cell cycle arrest at G2/M and induced apoptosis. Western blot results demonstrated that brevilin A could down-regulate cyclin D3, cdc2, p-PI3K, p-AKT, p-mTOR, and p-STAT3, while up-regulating cleaved PARP, cleaved caspase 9, and Bax. Regulation of cyclin B1, cdk6, and Bcl-2 expression by brevilin A showed dynamic changes according to dose and time. In the tumor xenograft model, brevilin A could reduce tumor growth, at a similar magnitude to cisplatin. However, notably, whereas cisplatin treatment led to significant weight loss in treated mice, treatment with brevilin A did not, indicating its relative lack of toxicity. Taken together, brevilin A regulated cell cycle, activated the caspase signaling pathway, and inhibited PI3K/AKT/mTOR and STAT3 signaling pathways in vitro, and exhibited similar efficacy to the common chemotherapeutic cisplatin in vivo, without its associated toxicity. These findings provide a framework for the preclinical development of brevilin A as a chemotherapeutic for NPC.

Arnicolide D, from the herb Centipeda minima, Is a Therapeutic Candidate against Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a high morbidity and mortality cancer with an obvious racial and geographic bias, particularly endemic to Southeast China. Our previous studies demonstrated that Centipeda minima extract (CME) exhibited anti-cancer effects in human NPC cell lines. Arnicolide C and arnicolide D are sesquiterpene lactones isolated from Centipeda minima. In this study, for the first time, we investigated their anti-NPC effects and further explored the related molecular mechanisms. The effects of both arnicolide C and arnicolide D were tested in NPC cells CNE-1, CNE-2, SUNE-1, HONE1, and C666-1. The results showed that the two compounds inhibited NPC cell viability in a concentration- and time-dependent manner. As the inhibitory effect of arnicolide D was the more pronounced of the two, our following studies focused on this compound. Arnicolide D could induce cell cycle arrest at G₂/M, and induce cell apoptosis. The molecular mechanism of cell cycle regulation and apoptosis induction was investigated, and the results showed that arnicolide D could downregulate cyclin D3, cdc2, p-PI3K, p-AKT, p-mTOR, and p-STAT3, and upregulate cleaved PARP, cleaved caspase 9, and Bax. Regulation of cyclin B1, cdk6, and Bcl-2 expression by arnicolide D showed dynamic changes according to dose and time. Taken together, arnicolide D modulated the cell cycle, activated the caspase signaling pathway, and inhibited the PI3K/AKT/mTOR and STAT3 signaling pathways. These findings provide a solid base of evidence for arnicolide D as a lead compound for further development, and act as proof for the viability of drug development from traditional Chinese medicines.