Xanthatin induces cell cycle arrest at G2/M checkpoint and apoptosis via disrupting NF-κB pathway in A549 non-small-cell lung cancer cells

Cardiotoxicity induced by xanthatin via activating apoptosis and ERS pathways in zebrafish

Xanthatin, a sesquiterpene lactone compound, isolated from Chinese herb, Xanthium strumarium L, has various activities, including anti-inflammatory, anti-tumor, anti-ulcer effects. However, it has been less studied in terms of its toxicity, especially the potential toxicity on heart. This study is mainly aimed to assess the cardiotoxicity of xanthatin in vivo using zebrafish larva and in vitro using cardiomyocytes H9C2. The cardiotoxicity in zebrafish was assessed by the pericardial edema, blood flow dynamics, SV-BA distance, and sub-intestinal vein. The apoptosis was determined by AO staining, the blood red cell reduction and distribution was detected by O-dianisidine staining, histopathological evaluations were detected by HE staining. The anti-proliferative and pro-apoptotic activities in H9C2 cells were assessed by EdU staining and Hoechst 33342/PI double staining. The in vivo results showed that xanthatin caused cardiac malformations and dysfunctions, including decreased heart rate, reduced red blood cell count, hemodynamics, stroke volume, increased SV-BA distance and sub-intestinal vein congestion. Furthermore, apoptosis occurred in the heart of the zebrafish after xanthatin exposure. Additionally, cat, Mn-sod, chop, perk, and hspa5 related to oxidative stress and ERS also changed by xanthatin. Apoptotic genes caspase3 and caspase9 were also increased. Moreover, the in vitro results showed that xanthatin had proapoptotic and antiproliferative effects. To sum up, these results suggest that xanthatin has cardiotoxicity and the oxidative stress, ERS and apoptosis pathways are involved in the cardiotoxicity induced by xanthatin. This finding will be helpful for the better understanding of the potential cardiotoxicity of xanthatin and the underlying mechanism.

Traditional Chinese medicine in lung cancer treatment

Lung cancer remains a major global health challenge and one of the leading causes of cancer-related deaths worldwide. Despite significant advancements in treatment, challenges such as drug resistance, side effects, metastasis and recurrence continue to impact patient outcomes and quality of life. In response, there is growing interest in complementary and integrative approaches to cancer care. Traditional Chinese medicine (TCM), with its long history, abundant clinical experience, holistic perspective and individualized approach, has garnered increasing attention for its role in lung cancer prevention and management. This review provides a comprehensive overview of the advances in TCM for lung cancer treatment, covering its theoretical foundation, treatment principles, clinical experiences and evidence supporting its efficacy. We also provide a systematic summary of the preclinical mechanisms, through which TCM impacts lung cancer, including the induction of cell death, reversal of drug resistance, inhibition of metastasis and modulation of immune responses. Additionally, future prospects for TCM in lung cancer treatment are discussed, offering insights into its expanded application and integration with modern medicine to address this challenging disease.

Prominent Naturally Derived Oxidative-Stress-Targeting Drugs and Their Applications in Cancer Treatment

The relationship between oxidative stress and cancer has been extensively studied and highlighted, along with its role in various aspects of angiogenesis. The modulation of oxidative levels and the adaptive mechanisms of oxidative stress in cancer systems are attractive research themes for developing anti-cancer strategies. Reactive oxygen species (ROS) are involved in various pathophysiological processes and play crucial roles in DNA damage and angiogenesis. Although cancer cells have developed various adaptive defense mechanisms against oxidative stress, excessive ROS production has been proposed as an anti-cancer strategy to induce cellular apoptosis. In particular, natural-source-based antioxidants have been identified as effective against cancers, and various delivery platforms have been developed to enhance their efficacy. In this review, we highlighted the anti-cancer components (plumbagin, quercetin, resveratrol, curcumin, xanthatin, carvacrol, telmisartan, and sulforaphane) that modulate ROS levels and the recent targeting platforms used to increase the application of anti-cancer drugs and the developed delivery platforms with diverse mechanisms of action. Further, we summarized the actual doses used and the effects of these drug candidates in various cancer systems. Overall, this review provides beneficial research themes for expanding cancer-targeting fields and addressing limited applications in diverse cancer types.

Therapeutic Efficacy of Quercetin and Its Nanoformulation Both the Mono- or Combination Therapies in the Management of Cancer: An Update with Molecular Mechanisms

Quercetin, a major representative of the flavonol subclass found abundantly in almost all edible vegetables and fruits, showed remarkable therapeutic properties and was beneficial in numerous degenerative diseases by preventing lipid peroxidation. Quercetin is beneficial in different diseases, such as atherosclerosis and chronic inflammation. This study aims to find out the anticancer activities of quercetin and to determine different mechanisms and pathways which are responsible for the anticancer effect. It also revealed the biopharmaceutical, toxicological characteristics, and clinical utilization of quercetin to evaluate its suitability for further investigations as a reliable anticancer drug. All of the relevant data concerning this compound with cancer was collected using different scientific search engines, including PubMed, Springer Link, Wiley Online, Web of Science, SciFinder, ScienceDirect, and Google Scholar. This review demonstrated that quercetin showed strong anticancer properties, including apoptosis, inhibition of cell proliferation, autophagy, cell cycle arrest, inhibition of angiogenesis, and inhibition of invasion and migration against various types of cancer. Findings also revealed that quercetin could significantly moderate and regulate different pathways, including PI3K/AKT-mTORC1 pathway, JAK/STAT signaling system, MAPK signaling pathway, MMP signaling pathway, NF-κB pathway, and p-Camk2/p-DRP1 pathway. However, this study found that quercetin showed poor oral bioavailability due to reduced absorption; this limitation is overcome by applying nanotechnology (nanoformulation of quercetin). Moreover, different investigations revealed that quercetin expressed no toxic effect in the investigated subjects. Based on the view of these findings, it is demonstrated that quercetin might be considered a reliable chemotherapeutic drug candidate in the treatment of different cancers. However, more clinical studies are suggested to establish the proper therapeutic efficacy, safety, and human dose.

Investigation into the Neuroprotective and Therapeutic Potential of Plant-Derived Chk2 Inhibitors

Nature provides us with a rich source of compounds with a wide range of applications, including the creation of innovative drugs. Despite advancements in chemically synthesized therapeutics, natural compounds are increasingly significant, especially in cancer treatment, a leading cause of death globally. One promising approach involves the use of natural inhibitors of checkpoint kinase 2 (Chk2), a critical regulator of DNA repair, cell cycle arrest, and apoptosis. Chk2's activation in response to DNA damage can lead to apoptosis or DNA repair, influencing glycolysis and mitochondrial function. In cancer therapy, inhibiting Chk2 can disrupt DNA repair and cell cycle progression, promoting cancer cell death and enhancing the efficacy of radiotherapy and chemotherapy. Additionally, Chk2 inhibitors can safeguard non-cancerous cells during these treatments by inhibiting p53-dependent apoptosis. Beyond oncology, Chk2 inhibition shows potential in treating hepatitis C virus (HCV) infections, as the virus relies on Chk2 for RNA replication in neurodegenerative diseases like amyotrophic lateral sclerosis (ALS), in which DNA damage plays a crucial role. Plant-derived Chk2 inhibitors, such as artemetin, rhamnetin, and curcumin, offer a promising future for treating various diseases with potentially milder side effects and broader metabolic impacts compared to conventional therapies. The review aims to underscore the immense potential of natural Chk2 inhibitors in various therapeutic contexts, particularly in oncology and the treatment of other diseases involving DNA damage and repair mechanisms. These natural Chk2 inhibitors hold significant promise for revolutionizing the landscape of cancer treatment and other diseases. Further research into these compounds could lead to the development of innovative therapies that offer hope for the future with fewer side effects and enhanced efficacy.

A mechanistic insight into the anticancer potentials of resveratrol: Current perspectives

Resveratrol is a widely recognized polyphenolic phytochemical found in various plants and their fruits, such as peanuts, grapes, and berry fruits. It is renowned for its several health advantages. The phytochemical is well known for its anticancer properties, and a substantial amount of clinical evidence has also established its promise as a chemotherapeutic agent. This study focuses on assessing the anticancer properties of resveratrol and gaining insight into the underlying molecular mechanisms. It also evaluates the biopharmaceutical, toxicological characteristics, and clinical utilization of resveratrol to determine its suitability for further development as a reliable anticancer agent. Therefore, the information about preclinical and clinical studies was collected from different electronic databases up-to-date (2018-2023). Findings from this study revealed that resveratrol has potent therapeutic benefits against various cancers involving different molecular mechanisms, such as induction of oxidative stress, cytotoxicity, inhibition of cell migration and invasion, autophagy, arresting of the S phase of the cell cycle, apoptotic, anti-angiogenic, and antiproliferative effects by regulating different molecular pathways including PI3K/AKT, p38/MAPK/ERK, NGFR-AMPK-mTOR, and so on. However, the compound has poor oral bioavailability due to reduced absorption; this limitation is overcome by applying nanotechnology (nanoformulation of resveratrol). Clinical application also showed therapeutic benefits in several types of cancer with no serious adverse effects. We suggest additional extensive studies to further check the efficacy, safety, and long-term hazards. This could involve a larger number of clinical samples to establish the compound as a reliable drug in the treatment of cancer.

A Study Against Colon Cancer Mechanism of Xanthium sibiricum Herba Based on Computer Simulation and Bioinformatics

INTRODUCTION

Cancer is one of the leading causes of death worldwide, accounting for nearly one in six deaths in 2020. As a folk medicine, Xanthium sibiricum Herba (XSH) has been used many times in clinical practice for the treatment of various diseases. With the increasing number of cancer patients, there is a clinical need to find effective anti-cancer drugs.

AIM

This study aims to explores the bioactivity and the anti-cancer mechanism of XSH.

METHODS

In this study, bioinformatics, network pharmacology, molecular docking, molecular dynamics simulation techniques, and apoptosis assay were used to explore the bioactivity and the anti- cancer mechanism of XSH.

RESULTS

Finally, seven active ingredients in XSH after the screening were obtained, the two most active compounds were β-sitosterol and aloe-emodin, and good anti-cancer activity of XSH was predicted.

DISCUSSION

Four core targets were obtained from the PPI network map, namely Caspase-3 (CASP3), Transcription factor AP-1 (JUN), Myc proto-oncogene protein (MYC), and cellular tumor antigen p53 (TP53). GO and KEGG analyses showed that the mechanism of XSH anti-cancer is mainly related to the apoptosis process, and the main signaling pathways are enriched in the p53 signaling pathway, Apoptosis, and MAPK signaling. The molecular docking and molecular dynamics simulation results showed that CASP3, JUN, MYC, and TP53 had a high affinity with β- sitosterol and aloe-emodin. Bioinformatics analyses demonstrated the importance of core targets. Apoptosis assay showed that XSH could significantly promote the apoptosis of cancer cells, and inhibit their proliferation and migration, especially colon cancer cells.

CONCLUSION

This study uncovered the main active components, bioactivities, and potential targets of XSH, and further revealed the multi-component, multi-target, and multi-pathway mechanism of XSH for cancer treatment and promoting apoptosis.

RTKN2 Inhibits the Growth, Migration, Invasion and Glycolysis of Lung Adenocarcinoma Cells by Inactivating the NF-κB Signalling Pathway

BACKGROUND

Lung adenocarcinoma (LUAD) is a malignant tumour that seriously threatens the life and health of people worldwide. This research was carried out to investigate the role of Rhotekin 2 (RTKN2) in LUAD progression.

METHODS AND RESULTS

The GEPIA online database was used to analyse abnormally expressed genes in lung adenocarcinoma and RTKN2 expression in various cancers. Cell proliferation was detected with CCK-8 and colony formation assays. Transwell assays were carried out to assess cell migration and invasion. The extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) were evaluated by a Seahorse XFe96 analyser. The interaction between RTKN2 and p65 was confirmed using a coimmunoprecipitation assay. RTKN2 expression was detected with qPCR, immunohistochemistry, and western blot assays. The p65 levels in the cytoplasm and nucleus were determined by western blot assays. RTKN2 levels were prominently decreased in LUAD tissues and cell lines. RTKN2 overexpression suppressed LUAD cell growth, invasion, migration, and glycolysis, while RTKN2 knockdown showed the opposite effects. Additionally, p65 could be negatively regulated by RTKN2. RTKN2 overexpression increased p65 levels in the cytoplasm but decreased p65 levels in the nucleus. Furthermore, blocking the NF-κB signalling pathway neutralized the effect of RTKN2 silencing in LUAD cells.

CONCLUSION

RTKN2 inhibited the malignant behaviour and glycolysis of LUAD cells by blocking the NF-κB signalling pathway, implying that RTKN2 could be a cancer suppressor in LUAD progression.

Xanthatin suppresses proliferation and tumorigenicity of glioma cells through autophagy inhibition via activation of the PI3K-Akt-mTOR pathway

Glioma is the most common and aggressive primary brain tumor in adults with high morbidity and mortality. Rapid proliferation and diffuse migration are the main obstacles to successful glioma treatment. Xanthatin, a sesquiterpene lactone purified from Xanthium strumarium L., possesses a significant antitumor role in several malignant tumors. In this study, we report that xanthatin suppressed glioma cells proliferation and induced apoptosis in a time- and concentration-dependent manner, and was accompanied by autophagy inhibition displaying a significantly reduced LC3 punctate fluorescence and LC3II/I ratio, decreased level of Beclin 1, while increased accumulation of p62. Notably, treating glioma cells with xanthatin resulted in obvious activation of the PI3K-Akt-mTOR signaling pathway, as indicated by increased mTOR and Akt phosphorylation, decreased ULK1 phosphorylation, which is important in modulating autophagy. Furthermore, xanthatin-mediated pro-apoptosis in glioma cells was significantly reversed by autophagy inducers (rapamycin or Torin1), or PI3K-mTOR inhibitor NVP-BEZ235. Taken together, these findings indicate that anti-proliferation and pro-apoptosis effects of xanthatin in glioma are most likely by inhibiting autophagy via activation of PI3K-Akt-mTOR pathway, suggesting a potential therapeutic strategy against glioma.

Xanthanolides in Xanthium L.: Structures, Synthesis and Bioactivity

Xanthanolides were particularly characteristic of the genus Xanthium, which exhibited broad biological effects and have drawn much attention in pharmacological application. The review surveyed the structures and bioactivities of the xanthanolides in the genus Xanthium, and summarized the synthesis tactics of xanthanolides. The results indicated that over 30 naturally occurring xanthanolides have been isolated from the genus Xanthium in monomeric, dimeric and trimeric forms. The bioassay-guided fractionation studies suggested that the effective fractions on antitumor activities were mostly from weak polar solvents, and xanthatin (1) was the most effective and well-studied xanthanolide. The varieties of structures and structure-activity relationships of the xanthanolides had provided the promising skeleton for the further study. The review aimed at providing guidance for the efficient preparation and the potential prospects of the xanthanolides in the medicinal industry.

How Should the Worldwide Knowledge of Traditional Cancer Healing Be Integrated with Herbs and Mushrooms into Modern Molecular Pharmacology?

Traditional herbal medicine (THM) is a "core" from which modern medicine has evolved over time. Besides this, one third of people worldwide have no access to modern medicine and rely only on traditional medicine. To date, drugs of plant origin, or their derivates (paclitaxel, vinblastine, vincristine, vinorelbine, etoposide, camptothecin, topotecan, irinotecan, and omacetaxine), are very important in the therapy of malignancies and they are included in most chemotherapeutic regimes. To date, 391,000 plant and 14,000 mushroom species exist. Their medical and biochemical capabilities have not been studied in detail. In this review, we systematized the information about plants and mushrooms, as well as their active compounds with antitumor properties. Plants and mushrooms are divided based on the regions where they are used in ethnomedicine to treat malignancies. The majority of their active compounds with antineoplastic properties and mechanisms of action are described. Furthermore, on the basis of the available information, we divided them into two priority groups for research and for their potential of use in antitumor therapy. As there are many prerequisites and some examples how THM helps and strengthens modern medicine, finally, we discuss the positive points of THM and the management required to transform and integrate THM into the modern medicine practice.

Cloning and Functional Characterization of Two Germacrene A Oxidases Isolated from Xanthium sibiricum

Sesquiterpene lactones (STLs) from the cocklebur Xanthium sibiricum exhibit significant anti-tumor activity. Although germacrene A oxidase (GAO), which catalyzes the production of Germacrene A acid (GAA) from germacrene A, an important precursor of germacrene-type STLs, has been reported, the remaining GAOs corresponding to various STLs’ biosynthesis pathways remain unidentified. In this study, 68,199 unigenes were studied in a de novo transcriptome assembly of X. sibiricum fruits. By comparison with previously published GAO sequences, two candidate X. sibiricum GAO gene sequences, XsGAO1 (1467 bp) and XsGAO2 (1527 bp), were identified, cloned, and predicted to encode 488 and 508 amino acids, respectively. Their protein structure, motifs, sequence similarity, and phylogenetic position were similar to those of other GAO proteins. They were most strongly expressed in fruits, according to a quantitative real-time polymerase chain reaction (qRT-PCR), and both XsGAO proteins were localized in the mitochondria of tobacco leaf epidermal cells. The two XsGAO genes were cloned into the expression vector for eukaryotic expression in Saccharomyces cerevisiae, and the enzyme reaction products were detected by gas chromatography–mass spectrometry (GC-MS) and liquid chromatography–mass spectrometry (LC-MS) methods. The results indicated that both XsGAO1 and XsGAO2 catalyzed the two-step conversion of germacrene A (GA) to GAA, meaning they are unlike classical GAO enzymes, which catalyze a three-step conversion of GA to GAA. This cloning and functional study of two GAO genes from X. sibiricum provides a useful basis for further elucidation of the STL biosynthesis pathway in X. sibiricum.

Xanthatin Selectively Targets Retinoblastoma by Inhibiting the PLK1-Mediated Cell Cycle

Purpose

Retinoblastoma is the most common primary intraocular malignant tumor in children. Although intra-arterial chemotherapy and conventional chemotherapy have become promising therapeutic approaches for advanced intraocular retinoblastoma, the side effects threaten health and are unavoidable, making the development of targeted therapy an urgent need. Therefore, we intended to find a potential drug for human retinoblastoma by screening an in-house compound library that included 89 purified and well-characterized natural products.

Methods

We screened a panel of 89 natural products in retinoblastoma cell lines to find the inhibitor. The inhibition of the identified inhibitor xanthatin on cell growth was detected through half-maximal inhibitory concentration (IC50), flow cytometry assay, and zebrafish model system. RNA-seq further selected the target gene PLK1.

Results

We reported the discovery of xanthatin as an effective inhibitor of retinoblastoma. Mechanistically, xanthatin selectively inhibited the proliferation of retinoblastoma cells by inducing cell cycle arrest and promoting apoptosis. Interestingly, xanthatin targeted PLK1-mediated cell cycle progression. The efficacy of xanthatin was further confirmed in zebrafish models.

Conclusions

Collectively, our data suggested that xanthatin significantly inhibited tumor growth in vitro and in vivo, and xanthatin could be a potential drug treatment for retinoblastoma.

A Novel Sesquiterpene Lactone Xanthatin-13-(pyrrolidine-2-carboxylic acid) Isolated from Burdock Leaf Up-Regulates Cells' Oxidative Stress Defense Pathway

The aim of our study was to identify novel molecules able to induce an adaptative response against oxidative stress during the first stages of metabolic syndrome. A cellular survival in vitro test against H₂O₂-based test was applied after pretreatment with various natural bitter Asteraceae extracts. This screening revealed potent protection from burdock leaf extract. Using chromatography and LC-MS—RMN, we then isolated and identified an original sesquiterpene lactone bioactive molecule: the Xanthatin-13-(pyrrolidine-2-carboxylic acid) (XPc). A real-time RT-qPCR experiment was carried out on three essential genes involved in oxidative stress protection: GPx, SOD, and G6PD. In presence of XPc, an over-expression of the G6PD gene was recorded, whereas no modification of the two others genes could be observed. A biochemical docking approach demonstrated that XPc had a high probability to directly interact with G6PD at different positions. One of the most probable docking sites corresponds precisely to the binding site of AG1, known to stabilize the G6PD dimeric form and enhance its activity. In conclusion, this novel sesquiterpene lactone XPc might be a promising prophylactic bioactive agent against oxidative stress and inflammation in chronic diseases such as metabolic syndrome or type 2 diabetes.

TMT-Based Quantitative Proteomic Analysis Identified Proteins and Signaling Pathways Involved in the Response to Xanthatin Treatment in Human HT-29 Colon Cancer Cells

BACKGROUND

Xanthatin is a plant-derived bioactive sesquiterpene lactone from the Xanthium strumarium L., and it has been used as a traditional Chinese medicine. Recently, many studies have reported that xanthatin has anticancer activity. However, a comprehensive understanding of the mechanism underlying the antitumor effects of xanthatin is still lacking.

OBJECTIVE

To systematically and comprehensively identify the underlying mechanisms of xanthatin on cancer cells, quantitative proteomic techniques were performed.

METHODS

Xanthatin induced HT-29 colon cancer cells death was detected by lactate dehydrogenase (LDH) release cell death assay. Differentially abundant proteins in two groups (control groups and xanthatin treatment groups) of human HT-29 colon cancer cells were identified using tandem mass tag (TMT) quantitative proteomic techniques. All the significant differentially abundant proteins were generally characterized by performing hierarchical clustering, Gene Ontology (GO) enrichment analyses and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. We chose Western blot analysis to validate the candidate proteins in the proteomics results.

RESULTS

A total of 5637 proteins were identified, of which 397 significantly differentially abundant proteins in the groups were quantified. Based on the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses, we found that p53-related signaling played an important role in xanthatin-treated HT-29 colon cancer cells. p53-upregulated modulator of apoptosis (Puma), Sestrin-2 and p14ARF, which were selected from among p53-related signaling proteins, were further validated, and the results were consistent with the tandem mass tag quantitative proteomic results.

CONCLUSION

We first investigated the molecular mechanism underlying the effects of xanthatin treatment on HT-29 colon cancer cells using tandem mass tag quantitative proteomic methods and provided a global comprehensive understanding of the antitumor effects of xanthatin. However, it is necessary to further confirm the function of the differentially abundant proteins and the potentially associated signaling pathways.

Xanthatin synergizes with cisplatin to suppress homologous recombination through JAK2/STAT4/BARD1 axis in human NSCLC cells

Xanthatin (Xa) is a bicyclic sesquiterpene lactone identified from the plant Xanthium L. with impressive antitumor activity, but the role of Xa in non‐small cell lung cancer (NSCLC) is not known. Here we found that Xa inhibits proliferation, migration, invasion and induces apoptosis in NSCLC cells. RNA sequencing and Gene set enrichment analysis revealed that Xa significantly activates p53 pathway and suppresses E2F targets, G2M checkpoint and MYC targets in A549 cells. Among these changed genes, the down‐regulated gene BARD1 triggered by Xa was identified as a candidate involved in Xa’s antitumor effect because of its vital role in homologous recombination (HR). Further studies demonstrated that Xa inhibits HR through the BARD1/BRCA1/RAD51 axis, which enhances cell sensitivity to cisplatin. Mechanistic studies showed that Xa inhibits BARD1 through the JAK2/STAT4 pathway. Our study revealed that Xa is a promising drug to treat NSCLC, especially in combination with conventional chemotherapy.

Clinical application and mechanism of traditional Chinese medicine in treatment of lung cancer

Lung cancer is a malignant tumor characterized by a rapid proliferation rate, less survivability, high mortality, and metastatic potential. This review focuses on updated research about the clinical application of traditional Chinese medicine (TCM) as an adjuvant therapy to lung cancer treatment and the mechanisms of TCM effect on lung cancer in vitro and in vivo. We summarized the recent 5 years of different research progress on clinical applications and antitumor mechanisms of TCM in the treatment of lung cancer. As a potent adjuvant therapy, TCM could enhance conventional treatments (chemotherapy, radiation therapy, and epidermal growth factor receptors [EGFRs] tyrosine kinase inhibitors [TKIs]) effects as well as provide synergistic effects, enhance chemotherapy drugs chemosensitivity, reverse drug resistance, reduce adverse reactions and toxicity, relieve patients’ pain and improve quality of life (QOL). After treating with TCM, lung cancer cells will induce apoptosis and/or autophagy, suppress metastasis, impact immune reaction, and therapeutic effect of EGFR-TKIs. Therefore, TCM is a promisingly potent adjuvant therapy in the treatment of lung cancer and its multiple mechanisms are worthy of an in-depth study.

The investigation of the potential antidepressant-like activity of Xanthium orientale subsp. italicum (Moretti) Greuter in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnobotanical surveys revealed that Xanthiumorientale subsp. italicum (Moretti) Greuter has been used against central nervous system disorders in Turkish folk medicine. The aim of the present study is to verify the folkloric assertion on this plant. The compounds responsible for the activity were investigated using bioassay-guided fractionation procedures.

MATERIALS AND METHODS

The antidepressant activity of the aqueous, n-hexane, ethyl acetate (EtOAc), methanol (MeOH) extracts; fractions and isolated compounds from active MeOH extract were evaluated by using the in vitro MAO inhibition assay and three different in vivo models namely forced swimming test, tail suspension test, and antagonism of tetrabenazine-induced ptosis, hypothermia, and suppression of locomotor activity. The results were compared with control and reference groups, and active compounds of the plant have been determined. Through the bioassay-guided fractionation procedures, two compounds were isolated from the active fraction and their structures were elucidated by spectroscopic methods.

RESULTS

The MeOH extract of the plant was found to possess antidepressant-like activity. This extract was then subjected to chromatographic techniques. Isolated sesquiterpene lactones were elucidated as xanthatin (1) and xanthinosin (2), which were responsible for the antidepressant-like activity.

CONCLUSIONS

This study discovered the antidepressant potential of X. orientale subsp. italicum. Using bioassay-guided fractionation and isolation techniques, xanthatin (1) and xanthinosin (2) were determined as the main active components of the leaves.

Xanthatin induces glioma cell apoptosis and inhibits tumor growth via activating endoplasmic reticulum stress-dependent CHOP pathway

Xanthatin is a natural sesquiterpene lactone purified from Xanthium strumarium L., which has shown prominent antitumor activity against a variety of cancer cells. In the current study, we investigated the effect of xanthatin on the growth of glioma cells in vitro and in vivo, and elucidated the underlying mechanisms. In both rat glioma C6 and human glioma U251 cell lines, xanthatin (1–15 μM) dose-dependently inhibited cell viability without apparent effect on the cell cycle. Furthermore, xanthatin treatment dose-dependently induced glioma cell apoptosis. In nude mice bearing C6 glioma tumor xenografts, administration of xanthatin (10, 20, 40 mg·kg⁻¹·d⁻¹, ip, for 2 weeks) dose-dependently inhibited the tumor growth, but did not affect the body weight. More importantly, xanthatin treatment markedly increased the expression levels of the endoplasmic reticulum (ER) stress-related markers in both the glioma cell lines as well as in C6 xenografts, including glucose-regulated protein 78, C/EBP-homologous protein (CHOP), activating factor 4, activating transcription factor 6, spliced X-box binding protein-1, phosphorylated protein kinase R-like endoplasmic reticulum kinase, and phosphorylated eukaryotic initiation factor 2a. Pretreatment of C6 glioma cells with the ER stress inhibitor 4-phenylbutyric acid (4-PBA, 7 mM) or knockdown of CHOP using small interfering RNA significantly attenuated xanthatin-induced cell apoptosis and increase of proapoptotic caspase-3. These results demonstrate that xanthatin induces glioma cell apoptosis and inhibits tumor growth via activating the ER stress-related unfolded protein response pathway involving CHOP induction. Xanthatin may serve as a promising agent in the treatment of human glioma.

Studies of Jatrogossone A as a Reactive Oxygen Species Inducer in Cancer Cellular Models

Natural products continue to provide a platform to study biological systems. A bioguided study of cancer cell models led us to a new member of the jatrophane natural products from Jatropha gossypiifolia, which was independently identified and characterized as jatrogossone A (1). Purification and structure elucidation was performed by column chromatography and high-performance liquid chromatography-mass spectrometry and NMR techniques, and the structure was confirmed via X-ray crystallography. The unique molecular scaffold of jatrogossone A prompted an evaluation of its mode of action. Cytotoxicity assays demonstrated that jatrogossone A displays selective antiproliferative activity against cancer cell models in the low micromolar range with a therapeutic window. Jatrogossone A (1) affects mitochondrial membrane potential (ΔΨm) in a time- and dose-dependent manner. This natural product induces radical oxygen species (ROS) selectively in cancer cellular models, with minimal ROS induction in noncancerous cells. Compound 1 induces ROS in the mitochondria, as determined by colocalization studies, and it induces mitophagy. It promotes also in vitro cell death by causing cell arrest at the G2/M stage, caspase (3/7) activation, and PARP-1 cleavage. The combined findings provide a potential mechanism by which 1 relies on upregulation of mitochondrial ROS to potentiate cytotoxic effects through intracellular signaling.

Xanthatin inhibits STAT3 and NF-κB signalling by covalently binding to JAK and IKK kinases

Aberrant activation of the signal transducer and activator of transcription 3 (STAT3) and the nuclear factor‐κB (NF‐κB) signalling pathways is associated with the development of cancer and inflammatory diseases. JAKs and IKKs are the key regulators in the STAT3 and NF‐κB signalling respectively. Therefore, the two families of kinases have been the major targets for developing drugs to regulate the two signalling pathways. Here, we report a natural compound xanthatin from the traditional Chinese medicinal herb Xanthium L. as a potent inhibitor of both STAT3 and NF‐κB signalling pathways. Our data demonstrated that xanthatin was a covalent inhibitor and its activities depended on its α‐methylene‐γ‐butyrolactone group. It preferentially interacted with the Cys243 of JAK2 and the Cys412 and Cys464 of IKKβ to inactivate their activities. In doing so, xanthatin preferentially inhibited the growth of cancer cell lines that have constitutively activated STAT3 and p65. These data suggest that xanthatin may be a promising anticancer and anti‐inflammation drug candidate.

Xanthium strumarium´s xanthatins induces mitotic arrest and apoptosis in CT26WT colon carcinoma cells

BACKGROUND

Colorectal cancer is one of the most common malignancies worldwide and is associated with high mortality rates. We previously reported that Xanthium strumarium L. induces mitotic arrest in proliferating cells, a process mediated by xanthatins.

HYPOTHESIS/AIM

The aim of this work is to study if xanthatins, isolated from X. strumarium total extract, affect the proliferative capacity of CT26WT colon cancer cells and, in consequence, if tumor growth and proliferation of (lung) metastatic sites can also be arrested in vivo.

STUDY DESIGN

This study consisted of both in vitro and in vivo experiments involving the CT26WT cell line and a subcutaneous mouse model of colon cancer. In vitro cell cycle progression, in vivo tumoral growth and anti-metastatic activity were analyzed to investigate whether xanthatins of X. strumarium induce mitotic arrest in proliferating colorectal carcinoma.

RESULTS

Our in vitro results show that X. strumarium, mediated by xanthatins, induces G₂/M arrest and impair anaphase entrance. This leads to a significant induction of apoptotic and necrotic in CT26WT cells, demonstrating their significant anti-proliferative activity through interfering with the mitotic apparatus. Furthermore, our in vivoresults reveal that X. strumarium inhibits both tumor growth and metastasis progression.

CONCLUSION

X. strumarium antitumor activities are mainly mediated by xanthatins through inhibition of tumor growth and metastasis, inducing mitotic arrest and apoptosis in colon carcinoma cells. These findings further confirm the therapeutic potential of X. strumarium in colorectal cancer.

The antitumour growth and antiangiogenesis effects of xanthatin in murine glioma dynamically evaluated by dynamic contrast-enhanced magnetic resonance imaging

To investigate the suppressive effects of xanthatin on glioma growth in a nude mouse xenograft model and rat orthotopic implantation model using magnetic resonance imaging (MRI) to dynamically monitor the antitumour growth and antiangiogenesis effects of xanthatin. The nude mouse xenograft tumour model and rat orthotopic implantation model were established to observe the antitumour effects of xanthatin in vivo. In the rat orthotopic implanted tumour model, MRI scanning was used to dynamically monitor the antitumour growth effect and evaluate the antiangiogenesis effect of xanthatin. We found that xanthatin at a dose of 0.4 mg/10 g dramatically decreased the growth of xenograft tumours in nude mice. The antiangiogenesis effect of xanthatin C6 glioma was evaluated by dynamic contrast-enhanced (DCE) MRI via comparison of the volume transfer constant (K^trans ) value, a parameter that reflects vessel permeability. We found that xanthatin at the doses of 8 and 16 mg/kg significantly decreased the K^trans value, which suggests that xanthatin has antiangiogenesis effects. These data demonstrate the suppressive effects of xanthatin on C6 glioma occur via antiangiogenesis. Meanwhile, this study also provides evidence for the application of quantitative parameters of DCE-MRI for dynamically evaluating the growth and angiogenesis of intracranial tumours and for experimental and clinical research.

Xanthatin Promotes Apoptosis via Inhibiting Thioredoxin Reductase and Eliciting Oxidative Stress

Xanthatin (XT), a naturally occurring sesquiterpene lactone presented in cocklebur ( Xanthium strumarium L.), is under development as a potential anticancer agent. Despite the promising anticancer effect of XT, the molecular mechanism underlying its cellular action has not been well elucidated. The mammalian thioredoxin reductase (TrxR) enzymes, the essential seleno-flavoproteins containing a penultimate selenocysteine (Sec) residue at the C-terminus, represent a promising target for cancer chemotherapeutic agents. In this study, XT inhibits both the purified TrxR and the enzyme in cells. The possible binding mode of XT with the TrxR protein is predicted by the covalent docking method. Mechanism studies reveal that XT targets the Sec residue of TrxR and inhibits the enzyme activity irreversibly. Simultaneously, the inhibition of TrxR by XT promotes the oxidative stress-mediated apoptosis of HeLa cells. Importantly, the knockdown of the enzyme sensitizes the cells to XT treatment. Targeting TrxR thus discloses a novel molecular mechanism in accounting for the cellular action of XT and provides insights into the development of XT as an anticancer agent.

Xanthatin triggers Chk1-mediated DNA damage response and destabilizes Cdc25C via lysosomal degradation in lung cancer cells

Previous studies had shown that xanthatin, a natural xanthanolide sesquiterpene lactone, could induce mitotic arrest and apoptosis in non-small cell lung cancer (NSCLC) cells. Here, we examined whether the DNA damage response (DDR) could be a primary cytotoxic event underlying xanthatin-mediated anti-tumor activity. Using EdU incorporation assay in combination with novel imaging flow cytometry, our data indicated that xanthatin suppressed DNA replication, prevented cells from G2/M entry and increased the spot count of γH2AX nuclear foci. Given that checkpoint kinase 1 (Chk1) represents a core component in DDR-mediated cell cycle transition and the phosphorylation on Ser-345 is essential for kinase activation and function, we surprisingly found xanthatin distinctly modulated Ser-345 phosphorylation of Chk1 in A549 and H1299 cells. Further investigation on Cdc25C/CDK1/CyclinB1 signaling cascade in the absence or presence of pharmacological DDR inhibitors showed that xanthatin directly destabilized the protein levels of Cdc25C, and recovery of p53 expression in p53-deficient H1299 cells further intensified xanthatin-mediated inhibition of Cdc25C, suggesting p53-dependent regulation of Cdc25C in a DDR machinery. Moreover, exogenous expression of Cdc25C was also substantially repressed by xanthatin and partially impaired xanthatin-induced G2 arrest. In addition, xanthatin could induce accumulation of ubiquitinated Cdc25C without undergoing further proteasomal degradation. However, an alternative lysosomal proteolysis of Cdc25C was observed. Interestingly, lysosome-like vesicles were produced upon xanthatin treatment, accompanied by rapid accumulation of lysosomal associated membrane protein LAPM-1. Furthermore, vacuolar proton (V)-ATPases inhibitor bafilomycin A1 and lysosomal proteases inhibitor leupeptin could remarkably overturn the levels of Cdc25C in xanthatin-treated H1299 cells. Altogether, these data provide insight into how xanthatin can be effectively targeted DDR molecules towards certain tumors.

Mus81 knockdown sensitizes colon cancer cells to chemotherapeutic drugs by activating CHK1 pathway

PURPOSE

The inhibition of Mus81, a critical DNA repair gene, is recently related to the chemosensitivity of several human cancer cells such as hepatocellular carcinoma (HCC) cells. However, the role of Mus81 knockdown in chemotherapy response of colon cancer cells remains largely unknown.

METHODS AND MATERIALS

The effects of Mus81 knockdown by lentivirus-mediated short hairpin RNA in sensitivity of HCT116 and LS180 colon cancer cell lines to four therapeutic drugs, including cisplatin (CDDP), were evaluated by MTT assay as well as a mouse model. Apoptosis and cell cycle distribution of HCT116 cell line was detected by flow cytometric analysis. Western blot was also employed to determine the expression of CHK1 pathway and apoptosis-related proteins in HCT116 cells and the xenograft mouse tumors.

RESULTS

Mus81 knockdown could significantly improve the chemosensitivity of colon cancer cells in vitro and in vivo, especially to CDDP. Mus81 knockdown also induced S phase arrest and elevated apoptosis in CDDP treated HCT116 cells through activating CHK1/CDC25A/CDK2 and CHK1/p53/Bax pathways, while these effects could be counteracted by CHK1 inhibition.

CONCLUSION

Mus81 knockdown improves the chemosensitivity of colon cancer cells by inducing S phase arrest and promoting apoptosis through activating CHK1 pathway.

Emerging Anti-Mitotic Activities and Other Bioactivities of Sesquiterpene Compounds upon Human Cells

We review the bio-activities of natural product sesquiterpenes and present the first description of their effects upon mitosis. This type of biological effect upon cells is unexpected because sesquiterpenes are believed to inactivate proteins through Michael-type additions that cause non-specific cytotoxicity. Yet, certain types of sesquiterpenes can arrest cells in mitosis as measured by cell biology, biochemical and imaging techniques. We have listed the sesquiterpenes that arrest cells in mitosis and analyzed the biological data that support those observations. In view of the biochemical complexity of mitosis, we propose that a subset of sesquiterpenes have a unique chemical structure that can target a precise protein(s) required for mitosis. Since the process of mitotic arrest precedes that of cell death, it is possible that some sesquiterpenes that are currently classified as cytotoxic might also induce a mitotic arrest. Our analysis provides a new perspective of sesquiterpene chemical biology.

Xanthium strumarium extract inhibits mammalian cell proliferation through mitotic spindle disruption mediated by xanthatin

ETHNOPHARMACOLOGICAL RELEVANCE

Xanthium strumarium L. is a member of the Asteraceae family popularly used with multiple therapeutic purposes. Whole extracts of this plant have shown anti-mitotic activity in vitro suggesting that some components could induce mitotic arrest in proliferating cells.

AIM OF THE SUDY

Aim of the present work was to characterize the anti-mitotic properties of the X. strumarium whole extract and to isolate and purify active molecule(s).

MATERIALS AND METHODS

The capacity of the whole extract to inhibit mitotic progression in mammalian cultured cells was investigated to identify its anti-mitotic activity. Isolation of active component(s) was performed using a bioassay-guided multistep separation procedure in which whole extract was submitted to a progressive process of fractionation and fractions were challenged for their anti-mitotic activity.

RESULTS

Our results show for the first time that X. strumarium whole extract inhibits assembly of the mitotic spindle and spindle-pole separation, thereby heavily affecting mitosis, impairing the metaphase to anaphase transition and inducing apoptosis. The purification procedure led to a fraction with an anti-mitotic activity comparable to that of the whole extract. Chemical analysis of this fraction showed that its major component was xanthatin.

CONCLUSIONS

The present work shows a new activity of X. strumarium extract, i.e. the alteration of the mitotic apparatus in cultured cells that may be responsible for the anti-proliferative activity of the extract. Anti-mitotic activity is shown to be mainly exerted by xanthatin.

Polypeptide Fraction from Arca subcrenata Induces Apoptosis and G2/M Phase Arrest in HeLa Cells via ROS-Mediated MAPKs Pathways

Arca subcrenata is documented in the literature of marine Traditional Chinese Medicine. Polypeptide fraction from A. subcrenata, coded as P2, was demonstrated to possess significant antitumor activity in our previous study. However, the underlying mechanism remains undefined. The present study was carried out to investigate the underlying antitumor mechanism of P2 in human cervical cancer HeLa cells by MTT, FCM, LSCM, and western blot assays. The results revealed that P2 significantly induced apoptosis of HeLa cells in a concentration- and time-dependent manner. High level of ROS was provoked by P2, which was in turn responsible for induction of apoptosis through activation of intrinsic mitochondrial pathway and JNK1/2, p38 MAPK pathways, as well as inhibition of ERK1/2 pathway, as evidenced by the abrogation of P2's effect on HeLa cells preincubated with the ROS scavenger NAC. P2 also was observed to display significant effect on G2/M phase arrest by downregulating the expression of cyclin B1/cdc2 complex and upregulating the expression of p21. These findings demonstrate that P2 induces apoptosis and G2/M phase arrest in HeLa cells through ROS-mediated MAPKs pathways, suggesting that P2 would be worth investigating as a promising agent within the scope of marine drugs for treatment of cervical cancer.

Aberrant expression of NF-κB in liver fluke associated cholangiocarcinoma: implications for targeted therapy

BACKGROUND

Up-regulation and association of nuclear factor kappa B (NF-κB) with carcinogenesis and tumor progression has been reported in several malignancies. In the current study, expression of NF-κB in cholangiocarcinoma (CCA) patient tissues and its clinical significance were determined. The possibility of using NF-κB as the therapeutic target of CCA was demonstrated.

METHODOLOGY

Expression of NF-κB in CCA patient tissues was determined using immunohistochemistry. Dehydroxymethylepoxyquinomicin (DHMEQ), a specific NF-κB inhibitor, was used to inhibit NF-κB action. Cell growth was determined using an MTT assay, and cell apoptosis was shown by DNA fragmentation, flow cytometry and immunocytofluorescent staining. Effects of DHMEQ on growth and apoptosis were demonstrated in CCA cell lines and CCA-inoculated mice. DHMEQ-induced apoptosis in patient tissues using a histoculture drug response assay was quantified by TUNEL assay.

PRINCIPAL FINDINGS

Normal bile duct epithelia rarely expressed NF-κB (subunits p50, p52 and p65), whereas all CCA patient tissues (n  =  48) over-expressed all NF-κB subunits. Inhibiting NF-κB action by DHMEQ significantly inhibited growth of human CCA cell lines in a dose- and time-dependent manner. DHMEQ increased cell apoptosis by decreasing the anti-apoptotic protein expressions-Bcl-2, XIAP-and activating caspase pathway. DHMEQ effectively reduced tumor size in CCA-inoculated mice and induced cell apoptosis in primary histocultures of CCA patient tissues.

CONCLUSIONS

NF-κB was over-expressed in CCA tissues. Inhibition of NF-κB action significantly reduced cell growth and enhanced cell apoptosis. This study highlights NF-κB as a molecular target for CCA therapy.

Xanthium strumarium L. extracts produce DNA damage mediated by cytotoxicity in in vitro assays but does not induce micronucleus in mice

Xanthium strumarium L. is a member of the Asteraceae commonly used in Cuba, mainly as diuretic. Some toxic properties of this plant have also been reported and, to date, very little is known about its genotoxic properties. The present work aims was to evaluate the potential cytotoxic and genotoxic risk of whole extract from Xanthium strumarium L. whole extract of aerial parts. No positive response was observed in a battery of four Salmonella typhimurium strains, when exposed to concentrations up to 5 mg/plate, with and without mammalian metabolic activation (liver microsomal S9 fraction from Wistar rats). In CHO cells, high concentrations (25-100 μg/mL) revealed significant reduction in cell viability. Results from sister chromatid exchanges, chromosome aberrations, and comet assay showed that X. strumarium extract is genotoxic at the highest concentration used, when clear cytotoxic effects were also observed. On the contrary, no increase in micronuclei frequency in bone marrow cells was observed when the extract was orally administered to mice (100, 500, and 2000 mg/Kg doses). The data presented here constitute the most complete study on the genotoxic potential of X. strumarium L. and show that the extract can induce in vitro DNA damage at cytotoxic concentrations.

Enantioselective synthesis of xanthatin

The enantioselective synthesis of cytostatic and antibiotic xanthatin (1 a) is reported. As a key intermediate, a bicyclic compound 2 was identified, which can be readily synthesized from methyl-2-furoic acid in diastereo- and enantiomerically pure form. Compound 2 can be functionalized regio- and stereoselectively at C-6 and C-7, allowing the facile introduction of the functionalities found in xanthatin, as well as the synthesis of derivatives thereof. Moreover, a robust strategy for the introduction of the exo-methylene group at C-3, commonly found in many sesquiterpenes, was developed that makes use of masking the alkene in the α,β-unsaturated carbonyl system by O-pivaoyl, which is stable under acidic and mild basic conditions but eliminated upon treatment with strong bases.

Neuroprotective effects of PEP-1-carbonyl reductase 1 against oxidative-stress-induced ischemic neuronal cell damage

Human carbonyl reductase 1 (CBR1) is a member of the NADPH-dependent short-chain dehydrogenase/reductase superfamily that is known to play an important role in neuronal cell survival via its antioxidant function. Oxidative stress is one of the major causes of degenerative disorders including ischemia. However, the role CBR1 plays with regard to ischemic injury is as yet poorly understood. Protein transduction domains such as PEP-1 are well known and now commonly used to deliver therapeutic proteins into cells. In this study, we prepared PEP-1-CBR1 protein and examined whether it protects against oxidative-stress-induced neuronal cell damage. PEP-1-CBR1 protein was efficiently transduced into hippocampal neuronal HT-22 cells and protected against hydrogen peroxide (H2O2)-induced neuronal cell death. Transduced PEP-1-CBR1 protein drastically inhibited H2O2-induced reactive oxygen species production, the oxidation of intracellular macromolecules, and the activation of mitogen-activated protein kinases, as well as cellular apoptosis. Furthermore, we demonstrated that transduced PEP-1-CBR1 protein markedly protected against neuronal cell death in the CA1 region of the hippocampus resulting from ischemic injury in an animal model. In addition, PEP-1-CBR1 protein drastically reduced activation of glial cells and lipid peroxidation in an animal model. These results indicate that PEP-1-CBR1 protein significantly protects against oxidative-stress-induced neuronal cell death in vitro and in vivo. Therefore, we suggest that PEP-1-CBR1 protein may be a therapeutic agent for the treatment of ischemic injuries as well as oxidative-stress-induced cell damage and death.

Condurango glycoside-rich components stimulate DNA damage-induced cell cycle arrest and ROS-mediated caspase-3 dependent apoptosis through inhibition of cell-proliferation in lung cancer, in vitro and in vivo

Chemotherapeutic potential of Condurango glycoside-rich components (CGS) was evaluated in NSCLC, in vitro and in BaP-intoxicated rats, in vivo. NSCLC cells were treated with different concentrations of CGS to test their effect on cell viability. Cellular morphology, DNA-damage, AnnexinV-FITC/PI, cell cycle regulation, ROS-accumulation, MMP, and expressions of related signalling genes were critically analysed. 0.22 μg/μl CGS (IC₅₀ dose at 24 h) was selected for the study. CGS-induced apoptosis via DNA damage was evidenced by DNA-ladder formation, increase of AnnexinV-positive cells, cell cycle arrest at subG0/G1 and differential expressions of apoptotic genes. ROS-elevation and MMP-depolarization with significant caspase-3 activation might lead to apoptotic cell death. Anti-proliferative activity was confirmed by EGFR-expression modulation. ROS accumulation and DNA-nick formation with tissue damage-repair activity after post-cancerous CGS treatment, in vivo, supported the in vitro findings. Overall results advocate considerable apoptosis-inducing potential of CGS against NSCLC, validating its use against lung cancer by CAM practitioners.

Determination of xanthatin by ultra high performance liquid chromatography coupled with triple quadrupole mass spectrometry: application to pharmacokinetic study of xanthatin in rat plasma

A sensitive, specific and rapid ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method has been established to study pharmacokinetic properties of xanthatin. Xanthatin, a compound which belongs to sesquiterpene lactone group, was determined in rat plasma with psoralen as internal standard. Chromatographic separation was performed on an Agilent Zorbax Eclipse plus C18 column (50 mm × 2.1 mm, 3.5 μm) with gradient elution system at a flow rate of 0.3 mL/min. The mobile phase was composed of methanol and 0.1% formic acid water solution. Analysis was performed under a triple-quadruple tandem mass-spectrometer with an electrospray ionization (ESI) source via the multiple reaction monitoring (MRM) mode to determine xanthatin at [M+H](+)m/z 247.3→m/z 205.2 and that of IS at [M+H](+)m/z 187.1→m/z 143.0 within 5 min. The assay method exhibited good separation of xanthatin from the interference of endogenous substances. The lower limit of quantification (LLOQ) was 1 ng/mL, with a good linearity within the concentration range of 1-5000 ng/mL (r=0.9990). Intra-day and inter-day precision RSD was less than 9.27%; intra-day and inter-day accuracy was 88.48% and 102.25% respectively. The extraction recoveries of xanthatin range from 82.12% to 89.55%, and the extraction RSD was less than 9.01%. The established LC-ESI-MS/MS method is rapid and sensitive, which has been successfully applied to quantify xanthatin in rat plasma for the first time.

Aldose reductase regulates acrolein-induced cytotoxicity in human small airway epithelial cells

Aldose reductase (AR), a glucose-metabolizing enzyme, reduces lipid aldehydes and their glutathione conjugates with more than 1000-fold efficiency (Km aldehydes 5-30 µM) relative to glucose. Acrolein, a major endogenous lipid peroxidation product as well as a component of environmental pollutants and cigarette smoke, is known to be involved in various pathologies including atherosclerosis, airway inflammation, COPD, and age-related disorders, but the mechanism of acrolein-induced cytotoxicity is not clearly understood. We have investigated the role of AR in acrolein-induced cytotoxicity in primary human small airway epithelial cells (SAECs). Exposure of SAECs to varying concentrations of acrolein caused cell death in a concentration- and time-dependent manner. AR inhibition by fidarestat prevented the low-dose (5-10 µM) but not the high-dose (>10 µM) acrolein-induced SAEC death. AR inhibition protected SAECs from low-dose (5 µM) acrolein-induced cellular reactive oxygen species (ROS). Inhibition of acrolein-induced apoptosis by fidarestat was confirmed by decreased condensation of nuclear chromatin, DNA fragmentation, comet tail moment, and annexin V fluorescence. Further, fidarestat inhibited acrolein-induced translocation of the proapoptotic proteins Bax and Bad from the cytosol to the mitochondria and that of Bcl2 and BclXL from the mitochondria to the cytosol. Acrolein-induced cytochrome c release from mitochondria was also prevented by AR inhibition. The mitogen-activated protein kinases (MAPKs), such as extracellular signal-regulated kinases 1 and 2, stress-activated protein kinase/c-Jun NH2-terminal kinase, and p38MAPK, and c-Jun were transiently activated in airway epithelial cells by acrolein in a concentration- and time-dependent fashion, which was significantly prevented by AR inhibition. These results suggest that AR inhibitors could prevent acrolein-induced cytotoxicity in the lung epithelial cells.

Concerted suppression of STAT3 and GSK3β is involved in growth inhibition of non-small cell lung cancer by Xanthatin

Xanthatin, a sesquiterpene lactone purified from Xanthium strumarium L., possesses prominent anticancer activity. We found that disruption of GSK3β activity was essential for xanthatin to exert its anticancer properties in non-small cell lung cancer (NSCLC), concurrent with preferable suppression of constitutive activation of STAT3. Interestingly, inactivation of the two signals are two mutually exclusive events in xanthatin-induced cell death. Moreover, we surprisingly found that exposure of xanthatin failed to trigger the presumable side effect of canonical Wnt/β-Catenin followed by GSK3β inactivation. We further observed that the downregulation of STAT3 was required for xanthatin to fine-tune the risk. Thus, the discovery of xanthatin, which has ability to simultaneously orchestrate two independent signaling cascades, may have important implications for screening promising drugs in cancer therapies.

A novel herbal formula induces cell cycle arrest and apoptosis in association with suppressing the PI3K/AKT pathway in human lung cancer A549 cells

AIM OF THE STUDY

In recent years, the incidence of lung cancer, as well as the mortality rate from this disease, has increased. Moreover, because of acquired drug resistance and adverse side effects, the effectiveness of current therapeutics used for the treatment of lung cancer has decreased significantly. Chinese medicine has been shown to have significant antitumor effects and is increasingly being used for the treatment of cancer. However, as the mechanisms of action for many Chinese medicines are undefined, the application of Chinese medicine for the treatment of cancer is limited. The formula tested has been used clinically by the China National Traditional Chinese Medicine Master, Professor Zhonging Zhou for treatment of cancer. In this article, we examine the efficacy of Ke formula in the treatment of non-small cell lung cancer and elucidate its mechanism of action.

METHODS

A Balb/c nude mouse xenograft model using A549 cells was previously established. The mice were randomly divided into normal, mock, Ke, cisplatin (DDP), and co-formulated (Ke + DDP) groups. After 15 days of drug administration, the animals were sacrificed, body weight and tumor volume were recorded, and the tumor-inhibiting rate was calculated. A cancer pathway finder polymerase chain reaction array was used to monitor the expression of 88 genes in tumor tissue samples. The potential antiproliferation mechanism was also investigated by Western blot analysis.

RESULTS

Ke formula minimized chemotherapy-related weight loss in tumor-bearing mice without exhibiting distinct toxicity. Ke formula also inhibited tumor growth, which was associated with the downregulation of genes in the PI3K/AKT, MAPK, and WNT/β-catenin pathways. The results from Western blot analyses further indicated that Ke blocked the cell cycle progression at the G1/S phase and induced apoptosis mainly via the PI3K/AKT pathway.

CONCLUSION

Ke formula inhibits tumor growth in an A549 xenograft mouse model with no obvious side effects. Moreover, Ke exhibits synergistic antitumor effects when combined with DDP. The mechanism of action of Ke is to induce cell cycle arrest and apoptosis by suppressing the PI3K/AKT pathway. Further research will be required to determine the mechanism of action behind the synergistic effect of Ke and DDP.

Natural sesquiterpenoids

This review covers the isolation, structural determination, synthesis and chemical and microbiological transformations of natural sesquiterpenoids. The literature from January to December 2012 is reviewed, and 471 references are cited.

Characterization of xanthatin: anticancer properties and mechanisms of inhibited murine melanoma in vitro and in vivo

Anti-cancer investigations on Xanthatin mainly focus on in vitro experiments. We herein reported the anti-tumor effects of Xanthatin both in vitro and in vivo. MTS assay results showed that Xanthatin had a remarkable anti-proliferative effect on B16-F10 cells. Moreover, the expression of β-catenin was up-regulated both in vitro and in vivo. Animal studies further revealed that Xanthatin killed the tumor cells around the blood vessels which contributes to reduce microvascular density extremely. All these results indicate that Xanthatin inhibited murine melanoma B16-F10 cell proliferation possibly associated with activation of Wnt/β-catenin pathway and its activity against melanoma tumor might also be relevant to inhibition of angiogenesis.