Ouabain suppresses the migratory behavior of lung cancer cells

Disrupting Na+ ion homeostasis and Na+/K+ ATPase activity in breast cancer cells directly modulates glycolysis in vitro and in vivo

BACKGROUND

Glycolytic flux is regulated by the energy demands of the cell. Upregulated glycolysis in cancer cells may therefore result from increased demand for adenosine triphosphate (ATP), however it is unknown what this extra ATP turnover is used for. We hypothesise that an important contribution to the increased glycolytic flux in cancer cells results from the ATP demand of Na+/K+-ATPase (NKA) due to altered sodium ion homeostasis in cancer cells.

METHODS

Live whole-cell measurements of intracellular sodium [Na+]i were performed in three human breast cancer cells (MDA-MB-231, HCC1954, MCF-7), in murine breast cancer cells (4T1), and control human epithelial cells MCF-10A using triple quantum filtered 23Na nuclear magnetic resonance (NMR) spectroscopy. Glycolytic flux was measured by 2H NMR to monitor conversion of [6,6-2H2]D-glucose to [2H]-labelled L-lactate at baseline and in response to NKA inhibition with ouabain. Intracellular [Na+]i was titrated using isotonic buffers with varying [Na+] and [K+] and introducing an artificial Na+ plasma membrane leak using the ionophore gramicidin-A. Experiments were carried out in parallel with cell viability assays, 1H NMR metabolomics of intracellular and extracellular metabolites, extracellular flux analyses and in vivo measurements in a MDA-MB-231 human-xenograft mouse model using 2-deoxy-2-[18F]fluoroglucose (18F-FDG) positron emission tomography (PET).

RESULTS

Intracellular [Na+]i was elevated in human and murine breast cancer cells compared to control MCF-10A cells. Acute inhibition of NKA by ouabain resulted in elevated [Na+]i and inhibition of glycolytic flux in all three human cancer cells which are ouabain sensitive, but not in the murine cells which are ouabain resistant. Permeabilization of cell membranes with gramicidin-A led to a titratable increase of [Na+]i in MDA-MB-231 and 4T1 cells and a Na+-dependent increase in glycolytic flux. This was attenuated with ouabain in the human cells but not in the murine cells. 18FDG PET imaging in an MDA-MB-231 human-xenograft mouse model recorded lower 18FDG tumour uptake when treated with ouabain while murine tissue uptake was unaffected.

CONCLUSIONS

Glycolytic flux correlates with Na+-driven NKA activity in breast cancer cells, providing evidence for the 'centrality of the [Na+]i-NKA nexus' in the mechanistic basis of the Warburg effect.

In Vitro Study of the Multimodal Effect of Na+/K+ ATPase Blocker Ouabain on the Tumor Microenvironment and Malignant Cells

Na+/K+ ATPase is a protein involved in the active transport of ions across the cellular membrane. Ouabain is a cardiotonic glycoside that, by inhibiting the Na+/K+ pump, interferes with cell processes mediated directly by the pump, but also indirectly influences other cellular processes such as cell cycle and proliferation, growth, cell differentiation, angiogenesis, migration, adhesion, and invasion. We used the SK-BR-3 breast cancer cell line, mesenchymal stem cells (MSCs), and tumor-associated fibroblasts (TAFs) in vitro to determine the effects of ouabain exposure on these cellular types. The results showed a multi-level effect of ouabain mainly on tumor cells, in a dose-dependent manner, while the TAFs and their normal counterparts were not significantly influenced. Following exposure to ouabain, the SK-BR-3 cells changed their morphologic appearance, decreased the expression of immunophenotypic markers (CD29, Her2, VEGF), the proliferation rate was significantly decreased (Ki67 index), the cells were blocked in the G0 phase of the cell cycle and suffered necrosis. These data were correlated with the variable expression of α and β Na+/K+ pump subunits in tumor cells, resulting in decreased ability to adhere to the VCAM-1 substrate in functional flow chamber studies. Being indicative of the pro-apoptotic and inhibitory effect of ouabain on tumor invasion and metastasis, the results support the addition of ouabain to the oncological therapeutic arsenal, trailing the "repurposing drugs" approach.

Potential Focal Adhesion Kinase Inhibitors in Management of Cancer: Therapeutic Opportunities from Herbal Medicine

Focal adhesion kinase (FAK) is a multifunctional protein involved in cellular communication, integrating and transducing extracellular signals from cell-surface membrane receptors. It plays a central role intracellularly and extracellularly within the tumor microenvironment. Perturbations in FAK signaling promote tumor occurrence and development, and studies have revealed its biological behavior in tumor cell proliferation, migration, and adhesion. Herein we provide an overview of the complex biology of the FAK family members and their context-dependent nature. Next, with a focus on cancer, we highlight the activities of FAK signaling in different types of cancer and how knowledge of them is being used for screening natural compounds used in herbal medicine to fight tumor development.

Immune senescence in non-small cell lung cancer management: therapeutic relevance, biomarkers, and mitigating approaches

INTRODUCTION

Lung cancer and mainly non-small cell lung cancer (NSCLC) still remain a prevalent malignancy worldwide despite sustained screening approaches. Furthermore, a significant proportion of the cases are diagnosed at advanced stages when conservative therapy is often unsuccessful. Cell senescence is an endogenous antitumor weapon but when it is upregulated exerts opposite activities favoring tumor metastasizing and poor response to therapy. However, little is known about this dangerous relationship between cell senescence and NSCLC outcome or on potential approaches to mitigate its unfavorable consequences.

AREAS COVERED

We discuss cell senescence focusing on immune senescence, its cell and humoral effectors (namely immune senescence associated secretory phenotype-iSASP), its impact on NSCLC outcome, and its biomarkers. Senotherapeutics as mitigating approaches are also considered based on the availability of experimental data pertinent to NSCLC.

EXPERT OPINION

Characterization of NSCLC subsets in which immune senescence is a risk factor for poor prognosis and poor therapeutic response might be very helpful in supporting the addition of senotherapeutics to conventional cancer therapy. This approach has the potential to improve disease outcome but more studies in this area are necessary.

Chemistry and the Potential Antiviral, Anticancer, and Anti-Inflammatory Activities of Cardiotonic Steroids Derived from Toads

Cardiotonic steroids (CTS) were first documented by ancient Egyptians more than 3000 years ago. Cardiotonic steroids are a group of steroid hormones that circulate in the blood of amphibians and toads and can also be extracted from natural products such as plants, herbs, and marines. It is well known that cardiotonic steroids reveal effects against congestive heart failure and atrial fibrillation; therefore, the term "cardiotonic" has been coined. Cardiotonic steroids are divided into two distinct groups: cardenolides (plant-derived) and bufadienolides (mainly of animal origin). Cardenolides have an unsaturated five-membered lactone ring attached to the steroid nucleus at position 17; bufadienolides have a doubly unsaturated six-membered lactone ring. Cancer is a leading cause of mortality in humans all over the world. In 2040, the global cancer load is expected to be 28.4 million cases, which would be a 47% increase from 2020. Moreover, viruses and inflammations also have a very nebative impact on human health and lead to mortality. In the current review, we focus on the chemistry, antiviral and anti-cancer activities of cardiotonic steroids from the naturally derived (toads) venom to combat these chronic devastating health problems. The databases of different research engines (Google Scholar, PubMed, Science Direct, and Sci-Finder) were screened using different combinations of the following terms: “cardiotonic steroids”, “anti-inflammatory”, “antiviral”, “anticancer”, “toad venom”, “bufadienolides”, and “poison chemical composition”. Various cardiotonic steroids were isolated from diverse toad species and exhibited superior anti-inflammatory, anticancer, and antiviral activities in in vivo and in vitro models such as marinobufagenin, gammabufotalin, resibufogenin, and bufalin. These steroids are especially difficult to identify. However, several compounds and their bioactivities were identified by using different molecular and biotechnological techniques. Biotechnology is a new tool to fully or partially generate upscaled quantities of natural products, which are otherwise only available at trace amounts in organisms.

Ouabain inhibits p38 activation in mice neutrophils

Ouabain is a cardiac steroid hormone with immunomodulatory effects. It inhibits neutrophils migration induced by different stimuli, but little is known about the mechanisms involved in this effect. Thus, the aim of this study was to evaluate the ouabain effect on chemotactic signaling pathways in neutrophils. For that, mice neutrophils were isolated from bone marrow, treated with ouabain (1, 10, and 100 nM) for 2 h, submitted to transwell chemotaxis assay and flow cytometry analysis of Akt, ERK, JNK, and p38 phosphorylation induced by zymosan. Ouabain treatment (1, 10 and, 100 nM) reduces neutrophil chemotaxis induced by chemotactic peptide fMLP, but this substance did not inhibit Akt, ERK, and JNK activation induced by zymosan. However, ouabain (1 and 10 nM) reduced p38 phosphorylation in zymosan-stimulated neutrophils. These results suggest that ouabain may interfere in neutrophil migration through p38 MAPK inhibition.

Erianthridin Induces Non-small Cell Lung Cancer Cell Apoptosis through the Suppression of Extracellular Signal-regulated Kinase Activity

Due to the high mortality of lung cancer, natural derivative compounds have been promoted as versatile sources for anticancer drug discovery. Erianthridin, a phenanthrene compound isolated from Dendrobium formosum, exhibits intriguing apoptosis-inducing effects in non-small cell lung cancer cells. Apoptotic nuclei staining assays showed that apoptotic cells with DNA fragmentation and apoptotic bodies were apparent, and an increase in annexin V-FITC-positive cells were found in cells treated with erianthridin. The apoptosis protein markers for cleaved caspase-3 and cleaved poly-ADP-ribose polymerase were significantly upregulated in response to erianthridin. A mechanistic investigation revealed that erianthridin was able to attenuate extracellular signal-regulated kinase activity and thereby mediate apoptosis through the modulation of Bcl-2 family protein levels. U0126, an extracellular signal-regulated kinase inhibitor, augmented the apoptosis-inducing effect of erianthridin; in contrast, overexpression of exogenous extracellular signal-regulated kinase substantially abrogated erianthridin activity. Furthermore, an in vitro 3D tumorigenesis assay showed that erianthridin was able to potentially suppress lung cancer cell proliferation. This study is the first to report a promising cytotoxic effect of erianthridin, which provides preclinical evidence for further research and development of this compound.

Na+/K+-ATPase Revisited: On Its Mechanism of Action, Role in Cancer, and Activity Modulation

Maintenance of Na⁺ and K⁺ gradients across the cell plasma membrane is an essential process for mammalian cell survival. An enzyme responsible for this process, sodium-potassium ATPase (NKA), has been currently extensively studied as a potential anticancer target, especially in lung cancer and glioblastoma. To date, many NKA inhibitors, mainly of natural origin from the family of cardiac steroids (CSs), have been reported and extensively studied. Interestingly, upon CS binding to NKA at nontoxic doses, the role of NKA as a receptor is activated and intracellular signaling is triggered, upon which cancer cell death occurs, which lies in the expression of different NKA isoforms than in healthy cells. Two major CSs, digoxin and digitoxin, originally used for the treatment of cardiac arrhythmias, are also being tested for another indication—cancer. Such drug repositioning has a big advantage in smoother approval processes. Besides this, novel CS derivatives with improved performance are being developed and evaluated in combination therapy. This article deals with the NKA structure, mechanism of action, activity modulation, and its most important inhibitors, some of which could serve not only as a powerful tool to combat cancer, but also help to decipher the so-far poorly understood NKA regulation.

Ouabain Exhibited Strong Anticancer Effects in Melanoma Cells via Induction of Apoptosis, G2/M Phase Arrest, and Migration Inhibition

Background

Malignant melanoma was characterized by insensitive chemotherapy, drug resistance, and high metastatic ability, which resulted in the main reason for the mortality among skin-related cancers. The current agents were not sufficient to improve the treatment status of melanoma patients, and it was still needed to develop new chemotherapeutic drugs for melanoma. Our study aimed to study the anticancer effects and potential mechanisms of ouabain on melanoma cells.

Methods

The inhibitory effects of ouabain were determined by CCK8 and colony formation assays, and the morphological changes of melanoma cells were observed by inverted microscope. The apoptosis induction and cell cycle distribution were detected by annexin V/PI double staining and PI staining, respectively. The expression of the biomarker proteins in apoptosis and G2/M phase were determined by Western blotting analysis. The effects of ouabain on the migration of melanoma cells were measured by transwell migration assay and wound closure analysis. The potential mechanisms of ouabain in melanoma cells were analyzed by transcriptome sequencing.

Results

Our present study demonstrated that ouabain exhibited strong inhibitory effects on cell proliferation and triggered dramatical morphological changes of melanoma cells. Moreover, ouabain induced significant apoptosis in A375 rather than SK-Mel-28 cells via upregulation of bax expression and downregulation of bcl-2 expression. Consistently, ouabain treatment induced cell cycle arrest at G2/M phase in both A375 and SK-Mel-28 cells via upregulation of cyclin B1 and downregulation of cdc2 and cdc25c. Importantly, ouabain suppressed the migration of A375 and SK-Mel-28 cells. Furthermore, the transcriptome sequencing demonstrated that p53 and MAPK signaling pathway might play important roles in the inhibitory effects of ouabain.

Conclusion

Our study revealed that ouabain exhibited dramatical anticancer effects, which provided a novel application for cardiac glycoside drugs in the clinical treatment of melanoma.

Cytotoxicity of glucoevatromonoside alone and in combination with chemotherapy drugs and their effects on Na+,K+-ATPase and ion channels on lung cancer cells

Cardiac glycosides (CGs) are useful drugs to treat cardiac illnesses and have potent cytotoxic and anticancer effects in cultured cells and animal models. Their receptor is the Na⁺,K⁺ ATPase, but other plasma membrane proteins might bind CGs as well. Herein, we evaluated the short- and long-lasting cytotoxic effects of the natural cardenolide glucoevatromonoside (GEV) on non-small-cell lung cancer H460 cells. We also tested GEV effects on Na⁺,K⁺ -ATPase activity and membrane currents, alone or in combination with selected chemotherapy drugs. GEV reduced viability, migration, and invasion of H460 cells spheroids. It also induced cell cycle arrest and death and reduced the clonogenic survival and cumulative population doubling. GEV inhibited Na⁺,K⁺-ATPase activity on A549 and H460 cells and purified pig kidney cells membrane. However, it showed no activity on the human red blood cell plasma membrane. Additionally, GEV triggered a Cl-mediated conductance on H460 cells without affecting the transient voltage-gated sodium current. The administration of GEV in combination with the chemotherapeutic drugs paclitaxel (PAC), cisplatin (CIS), irinotecan (IRI), and etoposide (ETO) showed synergistic antiproliferative effects, especially when combined with GEV + CIS and GEV + PAC. Taken together, our results demonstrate that GEV is a potential drug for cancer therapy because it reduces lung cancer H460 cell viability, migration, and invasion. Our results also reveal a link between the Na⁺,K⁺-ATPase and Cl^- ion channels.

Revealing the anticancer potential of candidate drugs in vivo using Caenorhabditis elegans mutant strains

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Mutations in the Wnt, Notch, and Ras-ERK signaling pathways in C. elegans lead to infertility, sterility, and multivulva formation.

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Phenotypic assays using C. elegans mutant strains can be used as in vivo models for drug repurposing.

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Itraconazole, disulfiram, etodolac, and ouabain have anticancer potential that can specifically target the Wnt, Notch, and RAS-ERK signaling pathways.

Drug repurposing is used as a strategy for finding new drugs for cancer. The process is a faster and a more cost-effective way of providing new indications for drugs that can address emerging drug resistance and numerous side effects of chemotherapeutic drugs. In this study, the in vivo anticancer potential of itraconazole, disulfiram, etodolac, and ouabain were assessed using five different C. elegans mutant strains. Each strain contains mutations in genes involved in different signaling pathways such as Wnt (JK3476), Notch (JK1107 and BS3164), and Ras-ERK (SD939 and MT2124) that result to phenotypes of sterility, infertility, and multivulva formation. These same signaling pathways have been shown to be defective in several human cancer types. The four candidate drugs were tested on the C. elegans mutant strains to determine if they rescue the mutant phenotypes. Both ouabain and etodolac significantly reduced the sterile and infertile phenotypes of JK3476, JK1107, BS3164, and SD939 strains (p=0.0010). Finally, itraconazole and etodolac significantly reduced multivulva formation (p=0.0021). The degrees of significant phenotypic rescues of each mutant were significantly higher than vehicle only (1% DMSO). Therefore, this study demonstrated that the four candidate drugs have anticancer potential in vivo, and etodolac had the highest anticancer potential.

Targeting Ion Channels for Cancer Treatment: Current Progress and Future Challenges

Ion channels are key regulators of cancer cell pathophysiology. They contribute to a variety of processes such as maintenance of cellular osmolarity and membrane potential, motility (via interactions with the cytoskeleton), invasion, signal transduction, transcriptional activity and cell cycle progression, leading to tumour progression and metastasis. Ion channels thus represent promising targets for cancer therapy. Ion channels are attractive targets because many of them are expressed at the plasma membrane and a broad range of existing inhibitors are already in clinical use for other indications. However, many of the ion channels identified in cancer cells are also active in healthy normal cells, so there is a risk that certain blockers may have off-target effects on normal physiological function. This review describes recent research advances into ion channel inhibitors as anticancer therapeutics. A growing body of evidence suggests that a range of existing and novel Na⁺, K⁺, Ca²⁺ and Cl^- channel inhibitors may be effective for suppressing cancer cell proliferation, migration and invasion, as well as enhancing apoptosis, leading to suppression of tumour growth and metastasis, either alone or in combination with standard-of-care therapies. The majority of evidence to date is based on preclinical in vitro and in vivo studies, although there are several examples of ion channel-targeting strategies now reaching early phase clinical trials. Given the strong links between ion channel function and regulation of tumour growth, metastasis and chemotherapy resistance, it is likely that further work in this area will facilitate the development of new therapeutic approaches which will reach the clinic in the future.

Rapid transient expression of functional human vascular endothelial growth factor in Nicotiana benthamiana and characterization of its biological activity

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Growth factors play a crucial role in wound healing.

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Plant-produced human vascular endothelial growth factor (hVEGF) induces the keratinocyte cells migration.

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The plant-produced hVEGF has shown potential as a wound healing agent in drug and cosmetic industry.

Human vascular endothelial growth factor (VEGF) is a potent pro-angiogenic growth factor essential for wound healing. Due to its potential applications, many expression strategies have been developed to produce high levels of VEGF. Here, we have optimized the expression conditions for the production of recombinant VEGF in Nicotiana benthamiana by using a geminiviral vector. Four different expression constructs that differ by the location of a C- or N-terminal histidine tag and SEKDEL sequence were developed and utilized for plant transient expression. The recombinant VEGF was further purified by using affinity chromatography and confirmed by SDS-PAGE and Western blotting probed with anti-VEGF antibody. Furthermore, our results showed that the recombinant VEGF in all tested concentrations did not exhibit any cytotoxic effect on HaCaT cells and induced cell migration in vitro. These findings show that the plant-produced VEGF has the potential to be used in regenerative medicine and cosmetic industry.

Ouabain pre-treatment modulates B and T lymphocytes and improves survival of melanoma-bearing animals

Ouabain (OUA) is a glycoside shown to modulate B and T lymphocytes. Nevertheless, ouabain effects on B16F10 melanoma immune response, a mouse lineage that mimics human melanoma, are still unknown. Our aim was to study how OUA in vivo treatment modulates lymphocytes and if it improves the response against B16F10 cells. C57BL/6 mice were pre-treated with intraperitoneal (i.p) injection of OUA (0.56 mg/Kg) for three consecutive days. On the 4^th day, 10⁶ B16F10 cells or vehicle were i.p. injected. Animals were euthanized on days 4^th and 21^st for organs removal and subsequent lymphocyte analyses by flow cytometry. In vivo ouabain-treatment reduced regulatory T cells in the spleen in both melanoma and non-melanoma groups. Ouabain preserved the number and percentage of B lymphocytes in peripheral organs of melanoma-injected mice. Melanoma-injected mice pre-treated with OUA also survive longer. Our findings contribute to a better understanding of OUA immunological effects in a melanoma model.

Role of Bioelectricity During Cell Proliferation in Different Cell Types

Most living organisms possess varying degrees of regenerative capabilities but how these regenerative processes are controlled is still poorly understood. Naturally occurring bioelectric voltages (like V_mem) are thought to be playing instructive role in tissue regeneration, as well as embryonic development. The different distribution of ions on the either side of the cell membrane results in intra- and extra-cellular voltage differences, known as membrane potential or V_mem. The relationship between V_mem and cell physiology is conserved in a wide range of cell types and suggests that V_mem regulation is a fundamental control mechanism for regeneration related processes e.g., proliferation and differentiation. In the present study we measured V_mem in three different cell types (human osteogenic sarcoma cell line (OSC), rat bone marrow derived mesenchymal stem cells (BM-MSC), and rat dermal fibroblasts) and characterized the relationship between their V_mem and proliferation. In order to find out if V_mem controls proliferation, or visa-versa, we blocked and then unblocked Na⁺/K⁺-exchanging ATPase using ouabain and measured the proliferation. Our results demonstrate that V_mem can be pharmacologically manipulated to control proliferation in certain cell types like BM-MSC. Taken together, it is clear that control of bioelectrical properties in non-excitable cells could prove to be potentially a useful tool in regenerative medicine efforts.

Discovery of selective, antimetastatic and anti-cancer stem cell metallohelices via post-assembly modification

Helicates and related metallofoldamers, synthesised by dynamic self-assembly, represent an area of chemical space inaccessible by traditional organic synthesis, and yet with potential for discovery of new classes of drug. Here we report that water-soluble, optically pure Fe(ii)- and even Zn(ii)-based triplex metallohelices are an excellent platform for post-assembly click reactions. By these means, the in vitro anticancer activity and most importantly the selectivity of a triplex metallohelix Fe(ii) system are dramatically improved. For one compound, a remarkable array of mechanistic and pharmacological behaviours is discovered: inhibition of Na+/K+ ATPase with potency comparable to the drug ouabain, antimetastatic properties (including inhibition of cell migration, re-adhesion and invasion), cancer stem cell targeting, and finally colonosphere inhibition competitive with the drug salinomycin.

Plumbagin-induced oxidative stress leads to inhibition of Na+/K+-ATPase (NKA) in canine cancer cells

The Na⁺/K⁺-ATPase (NKA) complex is the master regulator of membrane potential and a target for anti-cancer therapies. Here, we investigate the effect of drug-induced oxidative stress on NKA activity. The natural product, plumbagin increases oxygen radicals through inhibition of oxidative phosphorylation. As a result, plumbagin treatment results in decreased production of ATP and a rapid increase in intracellular oxygen radicals. We show that plumbagin induces apoptosis in canine cancer cells via oxidative stress. We use this model to test the effect of oxidative stress on NKA activity. Using whole-cell patch-clamp electrophysiology we demonstrate that short-term exposure (4 min) to plumbagin results in 48% decrease in outward current at +50 mV. Even when exogenous ATP was supplied to the cells, plumbagin treatment resulted in 46% inhibition of outward current through NKA at +50 mV. In contrast, when the canine cancer cells were pre-treated with the oxygen radical scavenger, N-acetylcysteine, the NKA inhibitory activity of plumbagin was abrogated. These experiments demonstrate that the oxidative stress-causing agents such as plumbagin and its analogues, are a novel avenue to regulate NKA activity in tumors.

A genome-wide positioning systems network algorithm for in silico drug repurposing

Recent advances in DNA/RNA sequencing have made it possible to identify new targets rapidly and to repurpose approved drugs for treating heterogeneous diseases by the 'precise' targeting of individualized disease modules. In this study, we develop a Genome-wide Positioning Systems network (GPSnet) algorithm for drug repurposing by specifically targeting disease modules derived from individual patient's DNA and RNA sequencing profiles mapped to the human protein-protein interactome network. We investigate whole-exome sequencing and transcriptome profiles from ~5,000 patients across 15 cancer types from The Cancer Genome Atlas. We show that GPSnet-predicted disease modules can predict drug responses and prioritize new indications for 140 approved drugs. Importantly, we experimentally validate that an approved cardiac arrhythmia and heart failure drug, ouabain, shows potential antitumor activities in lung adenocarcinoma by uniquely targeting a HIF1α/LEO1-mediated cell metabolism pathway. In summary, GPSnet offers a network-based, in silico drug repurposing framework for more efficacious therapeutic selections.

Ouabain-regulated phosphoproteome reveals molecular mechanisms for Na+, K+-ATPase control of cell adhesion, proliferation, and survival

The ion pump Na⁺, K⁺-ATPase (NKA) is a receptor for the cardiotonic steroid ouabain. Subsaturating concentration of ouabain triggers intracellular calcium oscillations, stimulates cell proliferation and adhesion, and protects from apoptosis. However, it is controversial whether ouabain-bound NKA is considered a signal transducer. To address this question, we performed a global analysis of protein phosphorylation in COS-7 cells, identifying 2580 regulated phosphorylation events on 1242 proteins upon 10- and 20-min treatment with ouabain. Regulated phosphorylated proteins include the inositol triphosphate receptor and stromal interaction molecule, which are essential for initiating calcium oscillations. Hierarchical clustering revealed that ouabain triggers a structured phosphorylation response that occurs in a well-defined, time-dependent manner and affects specific cellular processes, including cell proliferation and cell-cell junctions. We additionally identify regulation of the phosphorylation of several calcium and calmodulin-dependent protein kinases (CAMKs), including 2 sites of CAMK type II-γ (CAMK2G), a protein known to regulate apoptosis. To verify the significance of this result, CAMK2G was knocked down in primary kidney cells. CAMK2G knockdown impaired ouabain-dependent protection from apoptosis upon treatment with high glucose or serum deprivation. In conclusion, we establish NKA as the coordinator of a broad, tightly regulated phosphorylation response in cells and define CAMK2G as a downstream effector of NKA.-Panizza, E., Zhang, L., Fontana, J. M., Hamada, K., Svensson, D., Akkuratov, E. E., Scott, L., Mikoshiba, K., Brismar, H., Lehtiö, J., Aperia, A. Ouabain-regulated phosphoproteome reveals molecular mechanisms for Na⁺, K⁺-ATPase control of cell adhesion, proliferation, and survival.

Genetics, epigenetics and redox homeostasis in rhabdomyosarcoma: Emerging targets and therapeutics

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma accounting for 5-8% of malignant tumours in children and adolescents. Children with high risk disease have poor prognosis. Anti-RMS therapies include surgery, radiation and combination chemotherapy. While these strategies improved survival rates, they have plateaued since 1990s as drugs that target differentiation and self-renewal of tumours cells have not been identified. Moreover, prevailing treatments are aggressive with drug resistance and metastasis causing failure of several treatment regimes. Significant advances have been made recently in understanding the genetic and epigenetic landscape in RMS. These studies have identified novel diagnostic and prognostic markers and opened new avenues for treatment. An important target identified in high throughput drug screening studies is reactive oxygen species (ROS). Indeed, many drugs in clinical trials for RMS impact tumour progression through ROS. In light of such emerging evidence, we discuss recent findings highlighting key pathways, epigenetic alterations and their impacts on ROS that form the basis of developing novel molecularly targeted therapies in RMS. Such targeted therapies in combination with conventional therapy could reduce adverse side effects in young survivors and lead to a decline in long-term morbidity.

Ouabain promotes immune responses in WEHI-3 cells to generate leukemia mice through enhancing phagocytosis and natural killer cell activities in vivo

Ouabain, a cardiotonic steroid, was used for the treatment of heart failure and atrial fibrillation and induces cancer cell apoptosis in many human cancer cells including human leukemia cells. However, there are no reports to show the effects on immune responses in a leukemia mouse model. In this study, WEHI-3 cell generated leukemia mice were developed and treated by oral ouabain at 0, 0.75, 1.5, and 3 mg/kg for 15 days. Results indicated that ouabain did not affect body appearance, but decreased liver and spleen weights, B- and T-cell proliferation at all three doses treatment and increased CD19 cells at 3.0 mg/kg treatment, decreased CD3, CD11b, and Mac-3 cells levels compared with positive control. Furthermore, ouabain increased the macrophage phagocytosis from peripheral blood mononuclear cell and peritoneal cavity at all three doses treatment and increased NK cell activities. Ouabain restored GOT, GPT and LDH levels in WEHI-3 leukemia mice in vivo.

Continuous, label-free, 96-well-based determination of cell migration using confluence measurement

Cellular migration is essential in diverse physiological and pathophysiological processes. Here, we present a protocol for quantitative analysis of migration using confluence detection allowing continuous, non-endpoint measurement with minimal hands-on time under cell incubator conditions. Applicability was tested using substances which enhance (EGF) or inhibit (cytochalasin D, ouabain) migration. Using a gap-closure assay we demonstrate that automated confluence detection monitors cellular migration in the 96-well microplate format. Quantification by % confluence, % cell free-area or % confluence in cell-free area against time, allows detailed analysis of cellular migration. The study describes a practicable approach for continuous, non-endpoint measurement of migration in 96-well microplates and for detailed data analysis, which allows for medium/high-throughput analysis of cellular migration in vitro.

Pharmacological targeting of p38 MAP-Kinase 6 (MAP2K6) inhibits the growth of esophageal adenocarcinoma

Drug repurposing with a better understanding of the underlying mechanism has provided new avenues to find treatment for malignancies. Esophageal adenocarcinoma (EAC) is a rapidly increasing cancer with a dismal 5-year survival rate of <15%. Lack of efficient treatment options contributes to the high mortality rate of EAC. To find new therapy against EAC we performed unbiased drug screening of an FDA-approved drug library and identified that the cardiac glycosides including Ouabain, Digoxin and Digitoxin efficiently inhibit the proliferation of EAC cell lines (OE33 and OE19) both in vitro and in vivo. RNA-Sequencing analysis combined with RNAi screening revealed that Ouabain suppresses the proliferation of EAC cells through downregulation of p38 MAP-Kinase 6 (MAP2K6, also known as MKK6). Consistently, shRNA-mediated knockdown of MKK6 reduced the proliferation of EAC cells and tumor growth. Further analysis demonstrated that MKK6 inhibition leads to the reduced levels of the transcription factor SOX9. In line with this finding, deletion of SOX9 with CRISPR/Cas9 resulted in decreased proliferation of EACs in 3D organoid culture and reduced tumor growth. Together these findings establish a druggable axis that can be harnessed for therapeutic gain against EAC.

Annonacin promotes selective cancer cell death via NKA-dependent and SERCA-dependent pathways

In the healthcare sector, phytocompounds are known to be beneficial by contributing or alleviating a variety of diseases. Studies have demonstrated the progressive effects of phytocompounds on immune-related diseases and to exhibit anticancer effects. Graviola tree is an evergreen tree with its extracts (leafs and seeds) been reported having anticancer properties, but the precise target of action is not clear. Using an in silico approach, we predicted that annonacin, an Acetogenin, the active agent found in Graviola leaf extract (GLE) to potentially act as a novel inhibitor of both sodium/potassium (NKA) and sarcoplasmic reticulum (SERCA) ATPase pumps. We were able to validate and confirm the in silico studies by showing that GLE inhibited NKA and SERCA activity in intact cells. In the present study, we also demonstrated the antiproliferative and anticancer effects of GLE in a variety of cancer cell lines with limited toxic effects on non-transformed cells. Moreover, our results revealed that known inhibitors of both NKA and SERCA pumps could also promote cell death in several cancer cell lines. In addition, a mouse xenograft cancer model showed GLE as able to reduce tumor size and progression. Finally, bioprofiling studies indicated a strong correlation between overexpression of both NKA and SERCA gene expression vs. survival rates. Overall, our results demonstrated that GLE can promote selective cancer cell death via inhibiting NKA and SERCA, and thus can be considered as a potential novel treatment for cancer. After molecular analysis of GLE by liquid chromatography–mass spectrometry and ESI–QTOF–MS analysis, it was found that the MS spectrum of the high abundant chromatographic peak purified sample highly consisted of annonacin.

Cypripedin diminishes an epithelial-to-mesenchymal transition in non-small cell lung cancer cells through suppression of Akt/GSK-3β signalling

Lung cancer appears to have the highest rate of mortality among cancers due to its metastasis capability. To achieve metastasis, cancer cells acquire the ability to undergo a switch from epithelial to mesenchymal behaviour, termed the epithelial-to-mesenchymal transition (EMT), which is associated with poor clinical outcomes. Drug discovery attempts have been made to find potent compounds that will suppress EMT. Cypripedin, a phenanthrenequinone isolated from Thai orchid, Dendrobium densiflorum, exhibits diverse pharmacological activities. In this study, we found that cypripedin attenuated typical mesenchymal phenotypes, including migratory behaviour, of non-small cell lung cancer H460 cells, with a significant reduction of actin stress fibres and focal adhesion and with weakened anchorage-independent growth. Western blot analysis revealed that the negative activity of this compound on EMT was a result of the down-regulation of the EMT markers Slug, N-Cadherin and Vimentin, which was due to ATP-dependent tyrosine kinase (Akt) inactivation. As a consequence, the increase in the Slug degradation rate via a ubiquitin-proteasomal mechanism was encouraged. The observation in another lung cancer H23 cell line also supported this finding, indicating that cypripedin exhibits a promising pharmacological action on lung cancer metastasis that could provide scientific evidence for the further development of this compound.

Na+/K+ ATPase activity promotes invasion of endocrine resistant breast cancer cells

Background

The Na⁺/K⁺-ATPase (NKP) is an important ion transporter also involved in signal transduction. Its expression profile is altered in various tumours including that of the breast. We studied the effect of inhibiting NKP activity in non-tumorigenic breast cell line and in estrogen receptor positive and negative breast cancer cells.

Methods

Expression and localization of NKP and downstream signaling molecules were determined by RT-PCR, western blotting and immunofluorescence. Cell proliferation, apoptosis and cell cycle stage were determined using MTT, annexin V and flow cytometry. Cell motility and invasion were determined using wound healing and matrigel assays. Total matrix metalloproteinase (MMP) was determined by a fluorescence-based assay.

Results

NKP was mainly localized on the cell membrane. Its baseline expression and activity were enhanced in breast cancer compared to the non-tumorigenic breast cell line. Ouabain and 3,4,5,6-tetrahydroxyxanthone (TTX) treatment significantly inhibited NKP activity, which significantly reduced cell proliferation, motility, invasion and pH-induced membrane blebbing. EGF stimulation induced internalization of NKP from the cell membrane to the cytoplasm. Ouabain inhibited EGF-induced phosphorylation of Rac/cdc42, profillin, ERK1/2 and P70S6K.

Conclusions

The NKP may offer a novel therapeutic target in breast cancer patients who have developed metastasis, aiming to improve therapeutic outcomes and enhance survival rate.

Systemic analysis of gene expression profiles in porcine granulosa cells during aging

Current studies have revealed that aging is a negative factor that suppresses granulosa cell functions and causes low fertility in women. However, the difference in gene expression between normal and aging granulosa cells remains undefined. Therefore, the aim of this study was to investigate the gene expression profiles of granulosa cells during aging. Granulosa cells from young healthy porcine ovaries were aged in vitro by prolonging the culture time (for 48h). First, the extracellular ultrastructure was observed by scanning electron microscopy followed by RNA-seq and KEGG pathway analysis. The results showed that the extracellular ultrastructure was significantly altered by aging; cell membranes were rough, and cavitations were found. Moreover, the formations of filopodia were greatly reduced. RNA-seq data revealed that 3411 genes were differentially expressed during aging, of which 2193 genes were up-regulated and 1218 genes were down-regulated. KEGG pathway analysis revealed that 25 pathways including pathway in cancer, PI3K-Akt signaling pathway, focal adhesion, proteoglycans in cancer, and cAMP signaling pathway were the most changed. Moreover, several high differentially expressed genes (CEBPB, CXCL12, ANGPT2, IGFBP3, and BBOX1) were identified in aging granulosa cells, The expressions of these genes and genes associated with extracellular matrix remodeling associated genes (TIMP3, MMP2, MMP3, and CTGF), energy metabolism associated genes (SLC2A1, PPARγ) and steroidogenesis associated genes (StAR, CYP11A1 and LHCGR) were confirmed by quantitative PCR. This study identifies the differently changed pathways and their related genes, contributes to the understanding of aging in granulosa cells, and provides an important foundation for further studies.

Much More than a Cardiotonic Steroid: Modulation of Inflammation by Ouabain

Since the discovery of ouabain as a cardiotonic steroid hormone present in higher mammals, research about it has progressed rapidly and several of its physiological and pharmacological effects have been described. Ouabain can behave as a stress hormone and adrenal cortex is its main source. Direct effects of ouabain are originated due to the binding to its receptor, the Na⁺/K⁺-ATPase, on target cells. This interaction can promote Na⁺ transport blockade or even activation of signaling transduction pathways (e.g., EGFR/Src-Ras-ERK pathway activation), independent of ion transport. Besides the well-known effect of ouabain on the cardiovascular system and blood pressure control, compelling evidence indicates that ouabain regulates a number of immune functions. Inflammation is a tightly coordinated immunological function that is also affected by ouabain. Indeed, this hormone can modulate many inflammatory events such as cell migration, vascular permeability, and cytokine production. Moreover, ouabain also interferes on neuroinflammation. However, it is not clear how ouabain controls these events. In this brief review, we summarize the updates of ouabain effect on several aspects of peripheral and central inflammation, bringing new insights into ouabain functions on the immune system.

Anticancer and Immunogenic Properties of Cardiac Glycosides

Cardiac glycosides (CGs) are natural compounds widely used in the treatment of several cardiac conditions and more recently have been recognized as potential antitumor compounds. They are known to be ligands for Na/K-ATPase, which is a promising drug target in cancer. More recently, in addition to their antitumor effects, it has been suggested that CGs activate tumor-specific immune responses. This review summarizes the anticancer aspects of CGs as new strategies for immunotherapy and drug repositioning (new horizons for old players), and the possible new targets for CGs in cancer cells.

Ouabain impairs cell migration, and invasion and alters gene expression of human osteosarcoma U-2 OS cells

Ouabain, the specific Na⁺ /K⁺ -ATPase blocker, has biological activity including anti-proliferative and anti-metastasis effects in cancer cell. There is no study to show ouabain inhibiting cell migration and invasion in human osteosarcoma U-2 OS cells. Thus, we investigated the effect of ouabain on the cell migration and invasion of human osteosarcoma U-2 OS cells. Results indicated that ouabain significantly decreased the percentage of viable cells at 2.5-5.0 μM, thus, we selected 0.25-1.0 μM for inhibiting studies. Ouabain inhibited cell migration, invasion and the enzymatic activities of MMP-2, and also affected the expression of metastasis-associated protein in U-2 OS cells. The cDNA microarray assay indicated that CDH1, TGFBR3, SHC3 and MAP2K6 metastasis-related genes were increased, but CCND1, JUN, CDKN1A, TGFB1, 2 and 3, SMAD4, MMP13, MMP2 and FN1 genes were decreased. These findings provide more information regarding ouabain inhibited cell migration and invasion and associated gene expressions in U-2 OS cells after exposed to ouabain.

Ouabain attenuates ovalbumin-induced airway inflammation

PURPOSE

Ouabain, an Na⁺/K⁺-ATPase inhibitor hormone, presents immunomodulatory actions, including anti-inflammatory effect on acute inflammation models.

METHODS

In the present study, the effect of ouabain in a model of allergic airway inflammation induced by ovalbumin (OVA) was assessed.

RESULTS

Initially, it was observed that ouabain treatment inhibited cellular migration induced by OVA on bronchoalveolar lavage fluid (BALF), mostly granulocytes, without modulating macrophage migration. In addition, it was observed, by flow cytometry, that ouabain reduces CD3^high lymphocytes cells on BALF. Furthermore, treatment with ouabain decreased IL-4 and IL-13 levels on BALF. Ouabain also promoted pulmonary histological alterations, including decreased cell migration into peribronchiolar and perivascular areas, and reduced mucus production in bronchioles regions observed through hematoxylin-eosin (HE) and by periodic acid-Schiff stain, respectively. Allergic airway inflammation is characterized by high OVA-specific IgE serum titer. This parameter was also reduced by the treatment with ouabain.

CONCLUSIONS

Therefore, our data demonstrate that ouabain negatively modulates allergic airway inflammation induced by OVA.

Ouabain affects cell migration via Na,K-ATPase-p130cas and via nucleus-centrosome association

Na,K-ATPase is a membrane protein that catalyzes ATP to maintain transmembrane sodium and potassium gradients. In addition, Na,K-ATPase also acts as a signal-transducing receptor for cardiotonic steroids such as ouabain and activates a number of signalling pathways. Several studies report that ouabain affects cell migration. Here we used ouabain at concentrations far below those required to block Na,K-ATPase pump activity and show that it significantly reduced RPE cell migration through two mechanisms. It causes dephosphorylation of a 130 kD protein, which we identify as p130cas. Src is involved, because Src inhibitors, but not inhibitors of other kinases tested, caused a similar reduction in p130cas phosphorylation and ouabain increased the association of Na,K-ATPase and Src. Knockdown of p130cas by siRNA reduced cell migration. Unexpectedly, ouabain induced separation of nucleus and centrosome, also leading to a block in cell migration. Inhibitor and siRNA experiments show that this effect is mediated by ERK1,2. This is the first report showing that ouabain can regulate cell migration by affecting nucleus-centrosome association.

On the Many Actions of Ouabain: Pro-Cystogenic Effects in Autosomal Dominant Polycystic Kidney Disease

Ouabain and other cardenolides are steroidal compounds originally discovered in plants. Cardenolides were first used as poisons, but after finding their beneficial cardiotonic effects, they were rapidly included in the medical pharmacopeia. The use of cardenolides to treat congestive heart failure remained empirical for centuries and only relatively recently, their mechanisms of action became better understood. A breakthrough came with the discovery that ouabain and other cardenolides exist as endogenous compounds that circulate in the bloodstream of mammals. This elevated these compounds to the category of hormones and opened new lines of investigation directed to further study their biological role. Another important discovery was the finding that the effect of ouabain was mediated not only by inhibition of the activity of the Na,K-ATPase (NKA), but by the unexpected role of NKA as a receptor and a signal transducer, which activates a complex cascade of intracellular second messengers in the cell. This broadened the interest for ouabain and showed that it exerts actions that go beyond its cardiotonic effect. It is now clear that ouabain regulates multiple cell functions, including cell proliferation and hypertrophy, apoptosis, cell adhesion, cell migration, and cell metabolism in a cell and tissue type specific manner. This review article focuses on the cardenolide ouabain and discusses its various in vitro and in vivo effects, its role as an endogenous compound, its mechanisms of action, and its potential use as a therapeutic agent; placing especial emphasis on our findings of ouabain as a pro-cystogenic agent in autosomal dominant polycystic kidney disease (ADPKD).

Fenofibrate inhibits tumour intravasation by several independent mechanisms in a 3-dimensional co-culture model

Lymph node metastasis of breast cancer is a clinical marker of poor prognosis. Yet, there exist no therapies targeting mechanisms of intravasation into lymphatics. Herein we report on an effect of the antidyslipidemic drug fenofibrate with vasoprotective activity, which attenuates breast cancer intravasation in vitro, and describe the potential mechanisms. To measure intravasation in a 3-dimensional co-culture model MDA-MB231 and MCF-7 breast cancer spheroids were placed on immortalised lymphendothelial cell (LEC) monolayers. This provokes the formation of circular chemorepellent induced defects (CCIDs) in the LEC barrier resembling entry ports for the intravasating tumour. Furthermore, the expression of adhesion molecules ICAM-1, CD31 and FAK was investigated in LECs by western blotting as well as cell-cell adhesion and NF-κB activity by respective assays. In MDA-MB231 cells the activity of CYP1A1 was measured by EROD assay. Fenofibrate inhibited CCID formation in the MDA-MB231/LEC- and MCF-7/LEC models and the activity of NF-κB, which in turn downregulated ICAM-1 in LECs and the adhesion of cancer cells to LECs. Furthermore, CD31 and the activity of FAK were inhibited. In MDA-MB231 cells, fenofibrate attenuated CYP1A1 activity. Combinations with other FDA-approved drugs, which reportedly inhibit different ion channels, attenuated CCID formation additively or synergistically. In summary, fenofibrate inhibited NF-κB and ICAM-1, and inactivated FAK, thereby attenuating tumour intravasation in vitro. A combination with other FDA-approved drugs further improved this effect. Our new concept may lead to a novel therapy for cancer patients.

Cardiac glycoside-induced cell death and Rho/Rho kinase pathway: Implication of different regulation in cancer cell lines

Previously, we demonstrated that the Rho/ROCK pathway is involved in ouabain-induced apoptosis in HUVEC. In the current work, we investigated whether the Rho/ROCK pathway is functional during cardiac glycosides-induced cytotoxic effects in cancer cell lines, as well as in non-tumor cells. For that purpose, we evaluated the role of ROCK activation in bleb formation and cell migration over upstream and downstream effectors in addition to ROCK cleavage after cardiac glycosides treatment. All three cardiac glycosides (ouabain, digoxin and bufalin) induced cell death in HeLa and HepG2 cells and increased the formation of blebbing in HeLa cells. In contrast to our previous study, ROCK inhibitor Y27632 did not prevent bleb formation. Observation of ROCK II cleavage after ouabain, digoxin and oxaliplatin treatments in HeLa and/or HepG2 cells suggested that cleavage is independent of cell type and cell death induction. While inhibiting cleavage of ROCK II by the caspase inhibitors z-VAD-fmk, z-VDVAD-fmk and z-DEVD-fmk, evaluation of caspase 2 siRNA ineffectiveness on this truncation indicated that caspase-dependent ROCK II cleavage is differentially regulated in cancer cell lines. In HeLa cells, ouabain induced the activation of ROCK, although it did not induce phosphorylation of ERM, an upstream effector. While Y27632 inhibited the migration of HeLa cells, 10nM ouabain had no effect on cell migration. In conclusion, these findings indicate that the Rho/ROCK pathway is regulated differently in cancer cell lines compared to normal cells during cardiac glycosides-induced cell death.

Inhibition of cell proliferation, invasion and migration by the cardenolides digitoxigenin monodigitoxoside and convallatoxin in human lung cancer cell line

Cardiac glycosides consist of a large family of naturally derived compounds that are clinically used to treat congestive heart failure, and also present anticancer properties. In this study, the cytotoxic effects of two cardenolides, digitoxigenin monodigitoxoside (DGX) and convallatoxin (CON) were screened in four human tumour cell lines. Both compounds showed anti-proliferative effects in all tumour cells, at nanomolar concentrations. Since the human lung cancer cell line A549 was the most sensitive, we investigated the anti-proliferative, anti-migratory and anti-invasive effects of these cardenolides. DGX and CON reduced A549 cell migration, being able to reduce more than 90% of cell invasion. Their effects on the expression of key regulators of metastatic mechanism showed decreased levels of MMP-2, MMP-9 and p-FAK. Both compounds also presented low toxicity for healthy cells. Finally, this work provides the first insights into the effects of these cardenolides on key steps of lung cancer metastasis.

Natriuretic hormones in brain function

Natriuretic hormones (NH) include three groups of compounds: the natriuretic peptides (ANP, BNP and CNP), the gastrointestinal peptides (guanylin and uroguanylin), and endogenous cardiac steroids. These substances induce the kidney to excrete sodium and therefore participate in the regulation of sodium and water homeostasis, blood volume, and blood pressure (BP). In addition to their peripheral functions, these hormones act as neurotransmitters or neuromodulators in the brain. In this review, the established information on the biosynthesis, release and function of NH is discussed, with particular focus on their role in brain function. The available literature on the expression patterns of each of the NH and their receptors in the brain is summarized, followed by the evidence for their roles in modulating brain function. Although numerous open questions exist regarding this issue, the available data support the notion that NH participate in the central regulation of BP, neuroprotection, satiety, and various psychiatric conditions, including anxiety, addiction, and depressive disorders. In addition, the interactions between the different NH in the periphery and the brain are discussed.

Dendrofalconerol A sensitizes anoikis and inhibits migration in lung cancer cells

Resistance to anoikis, enhanced cell motility, and growth in anchorage-independent conditions are hallmarks of highly metastatic cancer cells. The present study demonstrates the anoikis-sensitizing and anti-migration activities of dendrofalconerol A (DF-A), a pure bis(bibenzyl) isolated from the stem of Dendrobium falconeri (Orchidaceae), and its underlying mechanisms in human lung cancer H460 cells. DF-A at non-toxic concentrations significantly increased the anoikis response of the cancer cells, but caused no toxic effect on normal keratinocytes. In addition, DF-A significantly inhibited the growth of lung cancer cells in anchorage-independent conditions. Western blot analysis revealed that the anoikis-sensitizing effect of such a compound involves its ability to suppress survival signals as well as anti-apoptotic proteins, namely, activated protein kinase B (Akt) and Bcl-2. Furthermore, DF-A decreased caveolin-1 (Cav-1), a protein responsible for aggressiveness, while having no effect on Bax, Mcl-1, and activated Erk (p42/44) proteins. In the case of cell motility, DF-A exhibited strong anti-migration activity with the mechanism involving suppression of pFAK and Rho-GTP, but had no effect on Rac-GTP in lung cancer cells. Taken together, DF-A possesses anoikis-sensitizing activity along with anti-migration effects, and may be developed as a novel active compound for cancer treatment.

The study of inducing apoptosis effect of fructose 1,6-bisphosphate on the papillary thyroid carcinoma cell and its related mechanism

This study aims to investigate the apoptosis-inducing effect of fructose 1,6-bisphosphate (F1,6BP) on the related mechanism of papillary thyroid carcinoma W3 and T cells. W3 cells were treated with F1,6BP alone or in combination with antioxidant catalase (CAT) or N-acetyl-L-cysteine (NAC). The changes of cell viability and cell nucleus morphology were examined by cell proliferation assay and Hoechst staining, and apoptosis levels of these cells were measured with flow cytometry. The changes of reactive oxygen species (ROS) level and the percentage of oxidized glutathione in total glutathione in W3 cells were detected by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining or colorimetry assay. At the same time, real-time fluorescence quantitative PCR was adopted to evaluate the expression levels of CAT and glutathione peroxidase (GSH-Px) mRNAs in W3 cells. F1,6BP inhibited the growth of W3 cells significantly, coupling with an increase in intracellular ROS level and the percentage of oxidized glutathione in total glutathione. Typical apoptotic morphological changes of the cell nucleus happened. The apoptosis rate and GSH-Px and CAT mRNAs expression levels were upregulated after F1,6BP treatment. The antitumor effect of F1,6BP was significantly decreased after W3 cells were pretreated with NAC and CAT. F1,6BP can induce the apoptosis of W3 cells through upregulating the generation of ROS, especially the production of H2O2.