Dimethyl fumarate induces necroptosis in colon cancer cells through GSH depletion/ROS increase/MAPKs activation pathway

Glutathione Synthesis in Cancer Cells

Tripeptide GSH is associated not only with the control and maintenance of redox cell homeostasis, but also with the processes of detoxification, proliferation, cell differentiation, and regulation of cell death. Disruptions in GSH synthesis and changes in the GSH/GSSG ratio are common for many pathological conditions, including malignant neoplasms. Numerous data indicate the importance of GSH and the GSH/GSSG ratio in the regulation of tumor cell viability, in the initiation of tumor development, progression, and drug resistance. However, control of the mechanism of GSH synthesis in malignant tumors remains poorly understood. This review discusses the features of GSH synthesis and its regulation in tumor cells. The role of GSH in the mechanisms of apoptosis, necroptosis, ferroptosis, and autophagy is considered.

3,3'-diindolylmethane exerts antiproliferation and apoptosis induction by TRAF2-p38 axis in gastric cancer

3,3'-diindolylmethane (DIM), an active phytochemical derivative extracted from cruciferous vegetables, possesses anticancer effects. However, the underlying anticancer mechanism of DIM in gastric cancer remains unknown. Tumor necrosis factor (TNF) receptor-associated factor 2 (TRAF2), one of the signal transduction proteins, plays critical role in proliferation and apoptosis of human gastric cancer cells, but there are still lack of practical pharmacological modulators for potential clinical application. Here, we further explored the role of TRAF2 in inhibiting cell proliferation and inducing apoptosis by DIM in human gastric cancer BGC-823 and SGC-7901 cells. After treating BGC-823 and SGC-7901 cells with DIM for 24 h, cell proliferation, apoptosis and TRAF2-related protein were measured. Our findings showed that DIM inhibited the expressions of TRAF2, activated p-p38 and its downstream protein p-p53, which were paralleled with DIM-triggered cells proliferation, inhibition and apoptosis induction. These effects of DIM were reversed by TRAF2 overexpression or p38 mitogen-activated protein kinase (MAPK)-specific inhibitor (SB203580). Taken together, our data suggest that regulating TRAF2/p38 MAPK signaling pathway is essential for inhibiting gastric cancer proliferation and inducing apoptosis by DIM. These findings broaden the understanding of the pharmacological mechanism of DIM's action as a new modulator of TRAF2, and provide a new therapeutic target for human gastric cancer.

Protective effects of selenium yeast against cadmium-induced necroptosis via inhibition of oxidative stress and MAPK pathway in chicken liver

The aim of the study was to investigate the protective effects of selenium yeast (SeY) against necroptosis triggered by Cd via inhibition of oxidative stress and MAPK pathway in the liver of chicken. Two hundred 120-day-old layers were randomly divided into four groups and raised for 120 days. The histopathological examination showed that necrosis characteristics were observed in Cd-exposed chicken livers. The exposure of Cd significantly reduced the activities of SOD, GSH-Px and CAT while improving MDA level in both serum and liver of chickens (P < 0.05), and induced oxidative stress. The MLKL, Rip1, RIP3, ERK, JNK and P38 mRNA expression of Cd group were significantly higher than other three groups (P ＜ 0.01), and those in the Se + Cd group were significantly higher than control group and Se group (P ＜ 0.01). However, the mRNA expression level of caspase8 of Cd was significantly lower than other three groups (P ＜ 0.01), and that in the Se + Cd group was significantly higher than control group and Se group (P ＜ 0.01), so the supplement of SeY could improve these situations. Similar results were also detected at the protein level. The results of the present study indicated that Cd could induce oxidative stress, activate MAPK pathway and evoke necroptosis damage in chicken livers, whereas SeY had protective effects in preventing this kind of Cd-induced injury by inhibition of oxidative stress and down-regulation MAPK pathway.

Intravitreal conbercept improves outcome of proliferative diabetic retinopathy through inhibiting inflammation and oxidative stress

Conbercept is a newly-developed anti-vascular endothelial growth factor (VEGF) drug. This study aimed to evaluate the effects of conbercept on inflammation and oxidative response in proliferative diabetic retinopathy (PDR). Morphology changes in retinal microvasculature of PDR patients were determined by optical coherence tomographic angiography (OCTA). The mice were injected with streptozocin (STZ) for 20 weeks to induced PDR, then the changes in inflammatory factors, oxidative response and histological analysis were examined with Elisa assay, real time-PCR and commercial kits analysis. Conbercept treatment significantly alleviated the retinal pathological changes and significantly reduced intercellular cell adhesion molecule-1 (ICAM-1), macrophage inflammatory protein-1 (MIP-1), IL-1β, IL-6 and TNF-α protein levels but not prostaglandin E1 (PGE1), prostaglandin E2 (PGE2) and prostaglandin F2a (PGF2a) levels, all of which were remarkably elevated in aqueous fluid of PDR patients compared with non-PDR subjects. Meanwhile the inhibitory effects of conbercept on these inflammatory factors were proved by RT-PCR assays in mice experiments. And the inflammatory signal such as p-IKBα and p-p65 was correspondingly inhibited by conbercept in STZ-treated mice. Conbercept treatment significantly elevated the aqueous glutathione level of PDR patients and inhibited NOX-1, NOX-4 and ph22phox mRNA expressions and ROS production of PDR mice. Ki67 immunofluorescence staining showed that conbercept inhibited endothelial cell proliferation in retina of PDR mice. In conclusion, conbercept significantly inhibited the angiogenesis, inflammation and oxidative response in PDR mice, and these findings further reveals the molecular mechanisms of conbercept in treating PDR.

The Role of Oxidative Stress and Its Counteractive Utility in Colorectal Cancer (CRC)

An altered redox status accompanied by an elevated generation of reactive oxygen/nitrogen species (ROS/RNS) has been implicated in a number of diseases including colorectal cancer (CRC). CRC, being one of the most common cancers worldwide, has been reported to be associated with multiple environmental and lifestyle factors (e.g., dietary habits, obesity, and physical inactivity) and harboring heightened oxidative stress that results in genomic instability. Although under normal condition ROS regulate many signal transduction pathways including cell proliferation and survival, overwhelming of the antioxidant capacity due to metabolic abnormalities and oncogenic signaling leads to a redox adaptation response that imparts drug resistance. Nevertheless, excessive reliance on elevated production of ROS makes the tumor cells increasingly vulnerable to further ROS insults, and the abolition of such drug resistance through redox perturbation could be instrumental to preferentially eliminate them. The goal of this review is to demonstrate the evidence that links redox stress to the development of CRC and assimilate the most up-to-date information that would facilitate future investigation on CRC-associated redox biology. Concomitantly, we argue that the exploitation of this distinct biochemical property of CRC cells might offer a fresh avenue to effectively eradicate these cells.

Exosomes released by human umbilical cord mesenchymal stem cells protect against renal interstitial fibrosis through ROS-mediated P38MAPK/ERK signaling pathway

Mesenchymal stem cells (MSCs) and their conditioned medium attenuate renal fibrosis in an irreversible model of unilateral ureteral obstruction (UUO). However, the key components that play a role in the paracrine effects of MSCs and their mechanisms of action are not well understood. Therefore, in this study, we investigated whether exosomes released by human umbilical cord mesenchymal stem cells (hucMSC-Ex) would be able to attenuate renal fibrosis in an irreversible model of UUO and further explored potential mechanisms. In vivo, rats were divided into four groups: sham operation, sham operation transplanted with hucMSC-Ex, UUO, and UUO transplanted with hucMSC-Ex. hucMSC-Ex was administered via the left renal artery after total ligation of the left ureter. Rats were sacrificed after 14 days of obstruction. Renal function such as serum creatinine (Scr) or blood urea nitrogen (BUN) were monitored over the period. Histological changes, proliferation and apoptosis in tubular epithelial cells, and the levels of oxidative stress were measured. In vitro, NRK-52E cells were incubated with or without 5 ng/ml TGF-β1 and co-incubated with or without hucMSC-Ex for 48 h. Apoptosis and the levels of oxidative stress of NRK-52E cells were also measured. In the UUO group, the level of BUN and Scr, and the level of apoptosis and oxidative stress were all increased. In addition, the renal tubular injury and tubulointerstitial fibrosis were evident. However, all the above indices decreased significantly after treatment with hucMSC-Ex. In vitro, hucMSC-Ex significantly inhibited TGF-β1-induced apoptosis of NRK-52E cells by altering the production of ROS. Furthermore, it was observed that hucMSC-Ex inhibited apoptosis by inhibiting the activation of p38 mitogen-activated protein kinase (p38MAPK)/extracellular-signal-regulated kinase (ERK) 1/2 pathway. In conclusion, the results showed that hucMSC-Ex had positive effects towards UUO-induced renal fibrosis and apoptosis of renal tubular epithelial cells, and its mechanism of action was associated with inhibition of ROS-mediated p38MAPK/ERK signaling pathway. These data suggest the potential application of hucMSC-Ex in the treatment of chronic kidney disease, and also reveal the underlying mechanism of hucMSC-Ex action.

Risk of cancer in multiple sclerosis (MS): A systematic review and meta-analysis

OBJECTIVE

To assess the pooled risk of cancer in patients with multiple sclerosis.

METHODS

We searched PubMed, Scopus, EMBASE, Web of Science, Ovid, google scholar and gray literature (references of studies, conference abstracts) which were published up to September 2019. The search strategy included the MeSH and text words as ((cancer) OR tumor) OR neoplasm) OR "malignant neoplasm) OR "benign neoplasm) AND (Multiple Sclerosis OR Sclerosis, Multiple) OR Sclerosis, Disseminated) OR Disseminated Sclerosis) OR MS (Multiple Sclerosis)) OR Multiple Sclerosis, Acute Fulminating).

RESULTS

The first literature search revealed 18,996 articles. After deletion of duplicate articles, finally, 264 articles remained. Excluding non-relevant articles, resulted in including 5 articles which met inclusion criteria. The RR estimated between 0.7 and 1.67 in included articles. The pooled RR estimated as 0.83 (95% CI:0.73-0.96) (I² = 90%, P < 0.001). Two studies provided prevalence of different cancers. The pooled prevalence of breast cancer in two studies was 2% (95%CI:2%-2%) (I² = 0%). The pooled prevalence of digestive system cancer in two studies was 2% (95%CI:1%-2%) (I² = 0%). The pooled prevalence of skin cancer in two studies was 1% (95%CI:0%-1%) (I² = 0).

CONCLUSION

The result of this systematic review showed that the risk of cancer in patients with MS is less than the general population.

The Role of Necroptosis in ROS-Mediated Cancer Therapies and Its Promising Applications

Over the past decades, promising therapies targeting different signaling pathways have emerged. Among these pathways, apoptosis has been well investigated and targeted to design diverse chemotherapies. However, some patients are chemoresistant to these therapies due to compromised apoptotic cell death. Hence, exploring alternative treatments aimed at different mechanisms of cell death seems to be a potential strategy for bypassing impaired apoptotic cell death. Emerging evidence has shown that necroptosis, a caspase-independent form of cell death with features between apoptosis and necrosis, can overcome the predicament of drug resistance. Furthermore, previous studies have also indicated that there is a close correlation between necroptosis and reactive oxygen species (ROS); both necroptosis and ROS play significant roles both under human physiological conditions such as the regulation of inflammation and in cancer biology. Several small molecules used in experiments and clinical practice eliminate cancer cells via the modulation of ROS and necroptosis. The molecular mechanisms of these promising therapies are discussed in detail in this review.

Targeting the Redox Landscape in Cancer Therapy

Reactive oxygen species (ROS) are produced predominantly by the mitochondrial electron transport chain and by NADPH oxidases in peroxisomes and in the endoplasmic reticulum. The antioxidative defense counters overproduction of ROS with detoxifying enzymes and molecular scavengers, for instance, superoxide dismutase and glutathione, in order to restore redox homeostasis. Mutations in the redox landscape can induce carcinogenesis, whereas increased ROS production can perpetuate cancer development. Moreover, cancer cells can increase production of antioxidants, leading to resistance against chemo- or radiotherapy. Research has been developing pharmaceuticals to target the redox landscape in cancer. For instance, inhibition of key players in the redox landscape aims to modulate ROS production in order to prevent tumor development or to sensitize cancer cells in radiotherapy. Besides the redox landscape of a single cell, alternative strategies take aim at the multi-cellular level. Extracellular vesicles, such as exosomes, are crucial for the development of the hypoxic tumor microenvironment, and hence are explored as target and as drug delivery systems in cancer therapy. This review summarizes the current pharmaceutical and experimental interventions of the cancer redox landscape.

Diethylnitrosamine and thioacetamide-induced hepatic damage and early carcinogenesis in rats: Role of Nrf2 activator dimethyl fumarate and NLRP3 inhibitor glibenclamide

Two-stage rat hepatocarcinogenesis model was used to induce early carcinogenesis in which thioacetamide (TAA) promotes diethylnitrosamine (DEN) initiated carcinogenesis. Dimethyl fumarate (DMF) used to treat multiple sclerosis, activates the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant responsive element (ARE) pathway during oxidative stress, and maintains antioxidant levels. Glibenclamide (GLB), a sulphonylurea drug used to treat type II diabetes, possesses anti-inflammatory properties and inhibits NLRP3 inflammasomes. The present study was designed to investigate the concurrent intervention of DMF and GLB on DEN + TAA-induced early hepatic carcinogenesis. DMF and GLB treatment improved DEN + TAA-induced decrease in body weight, increase in liver weight and plasma transaminases, histopathological alterations, DNA damage, and apoptosis. DMF and GLB intervention significantly ameliorated the DEN + TAA-induced alterations in the antioxidant (Nrf2, HO-1, SOD-1, catalase), inflammatory (NF-κB, NLRP3, ASC, caspase-1), fibrogenic (TGF-β1, collagen) and regenerative proliferative stress (GST-p, HGF, c-MET, TGFα, EGF, AFP) markers. The present results indicate that Nrf2/ARE activation and NLRP3 inhibition might be a rational approach to attenuate oxidative stress and chronic inflammation associated progression of hepatocarcinogenesis.

Multiple Sclerosis and Cancer: The Ying-Yang Effect of Disease Modifying Therapies

Over the past two decades, the field of multiple sclerosis (MS) has been transformed by the rapidly expanding arsenal of new disease modifying therapies (DMTs). Current DMTs for MS aim to modulate innate and adaptive immune responses toward a less inflammatory phenotype. Since the immune system is also critical for identifying and eliminating malignant cells, immunosuppression from DMTs may predictably increase the risk of cancer development in MS patients. Compared with healthy controls, patients with autoimmune conditions, such as MS, may already have a higher risk of developing certain malignancies and this risk may further be magnified by DMT treatments. For those patients who develop both MS and cancer, these comorbid presentations create a challenge for clinicians on how to therapeutically address management of cancer in the context of MS autoimmunity. As there are currently no accepted guidelines for managing MS patients with prior history of or newly developed malignancy, we undertook this review to evaluate the molecular mechanisms of current DMTs and their potential for instigating and treating cancer in patients living with MS.

Fisetin, a phytopolyphenol, targets apoptotic and necroptotic cell death in HepG2 cells

Fisetin (3,7,3',4'-tetrahydroxyflavone), a bioactive dietary flavonoid, intrigued scientists for its anticancer potential against various cancer types. We investigated the fisetin-induced inhibition of growth and survival of human hepatocellular carcinoma. Fisetin decreased cell viability and proliferation of HepG2 cells as revealed from MTT and clonogenicity assays. Cell cycle arrest in the G2/M phase was observed. Annexin V/propidium iodide (PI) staining followed by flow cytometry revealed that fisetin induced both apoptosis and necroptosis in HepG2 cells. Apoptotic cells were significantly increased on fisetin treatment as observed in morphological evaluations and 4',6-diamidino-2-phenylindole and Acridine orange staining. Flow cytometry, fluorescence imaging, and 2', 7'-dichlorofluorescein diacetate analyses showed an increase in reactive oxygen species (ROS) generation on fisetin treatment. Pretreatment with N-acetyl cysteine inhibited ROS production and also rescued mitochondrial membrane potential in HepG2 cells. The underlying mechanisms of apoptosis and necroptosis were determined by analysis of their respective signaling molecules using qRT-PCR and Western blotting. Fisetin showed a marked increase in the expression of TNFα and IKκB with a decrease in NF-κB, pNF-κB and pIKκB expression. Fisetin reduced the expression of Bcl2, and elevated levels of Bax, caspase-3, and PARP and thus induced apoptosis in HepG2 cells. zVAD suppressed the fisetin-induced expression of caspase-8, RIPK1, RIPK3, and MLKL as opposed to fisetin treatment. Nec-1 + fisetin could not completely block necroptosis, which warrants further investigation. Taken together, our findings demonstrate that the fisetin exhibited anti-proliferative effects on HepG2 cells through apoptosis and necroptosis via multiple signaling pathways. Fiestin has potential as a therapeutic agent against hepatocellular carcinoma.

Current translational potential and underlying molecular mechanisms of necroptosis

Cell death has a fundamental impact on the evolution of degenerative disorders, autoimmune processes, inflammatory diseases, tumor formation and immune surveillance. Over the past couple of decades extensive studies have uncovered novel cell death pathways, which are independent of apoptosis. Among these is necroptosis, a tightly regulated, inflammatory form of cell death. Necroptosis contribute to the pathogenesis of many diseases and in this review, we will focus exclusively on necroptosis in humans. Necroptosis is considered a backup mechanism of apoptosis, but the in vivo appearance of necroptosis indicates that both caspase-mediated and caspase-independent mechanisms control necroptosis. Necroptosis is regulated on multiple levels, from the transcription, to the stability and posttranslational modifications of the necrosome components, to the availability of molecular interaction partners and the localization of receptor-interacting serine/threonine-protein kinase 1 (RIPK1), receptor-interacting serine/threonine-protein kinase 3 (RIPK3) and mixed lineage kinase domain-like protein (MLKL). Accordingly, we classified the role of more than seventy molecules in necroptotic signaling based on consistent in vitro or in vivo evidence to understand the molecular background of necroptosis and to find opportunities where regulating the intensity and the modality of cell death could be exploited in clinical interventions. Necroptosis specific inhibitors are under development, but >20 drugs, already used in the treatment of various diseases, have the potential to regulate necroptosis. By listing necroptosis-modulated human diseases and cataloging the currently available drug-repertoire to modify necroptosis intensity, we hope to kick-start approaches with immediate translational potential. We also indicate where necroptosis regulating capacity should be considered in the current applications of these drugs.

Dimethylfumarate Inhibits Colorectal Carcinoma Cell Proliferation: Evidence for Cell Cycle Arrest, Apoptosis and Autophagy

Recent studies have proven that Dimethylfumarate (DMF) has a marked anti-proliferative impact on diverse cancer entities e.g., on malignant melanoma. To explore its anti-tumorigenic potential, we examined the effects of DMF on human colon carcinoma cell lines and the underlying mechanisms of action. Human colon cancer cell line HT-29 and human colorectal carcinoma cell line T84 were treated with or without DMF. Effects of DMF on proliferation, cell cycle progression, and apoptosis were analyzed mainly by Bromodeoxyuridine (BrdU)- and Lactatdehydrogenase (LDH)assays, caspase activation, flowcytometry, immunofluorescence, and immunoblotting. In addition, combinational treatments with radiation and chemotherapy were performed. DMF inhibits cell proliferation in both cell lines. It was shown that DMF induces a cell cycle arrest in G0/G1 phase, which is accompanied by upregulation of p21 and downregulation of cyclin D1 and Cyclin dependent kinase (CDK)4. Furthermore, upregulation of autophagy associated proteins suggests that autophagy is involved. In addition, the activation of apoptotic markers provides evidence that apoptosis is involved. Our results show that DMF supports the action of oxaliplatin in a synergetic manner and failed synergy with radiation. We demonstrated that DMF has distinct antitumorigenic, cell dependent effects on colon cancer cells by arresting cell cycle in G0/G1 phase as well as activating both the autophagic and apoptotic pathways and synergizes with chemotherapy.

Quetiapine induces myocardial necroptotic cell death through bidirectional regulation of cannabinoid receptors

Quetiapine is a common atypical antipsychotic used to treat mental disorders such as schizophrenia, bipolar disorder, and major depressive disorder. There has been increasing number of reports describing its cardiotoxicity. However, the molecular mechanisms underlying quetiapine-induced myocardial injury remain largely unknown. Herein, we reported a novel cell death type, quetiapine-induced necroptosis, which accounted for quetiapine cardiotoxicity in mice and proposed novel therapeutic strategies. Quetiapine-treated hearts showed inflammatory infiltration and evident fibrosis after 21-day continuous injection. The specific increases of protein levels of RIP3, MLKL and the phosphorylation of MLKL showed that quetiapine induced necroptotic cell death both in vivo and in vitro. Pharmacologic blockade of necroptosis using its specific inhibitor Necrostatin-1 attenuated quetiapine-induced myocardial injury in mice. In addition, quetiapine imbalanced the endocannabinoid system and caused opposing effects on two cannabinoid receptors (CB1R and CB2R). Specific antagonists of CB1R (AM 281, Rimonabant), but not its agonist ACEA significantly ameliorated the heart histopathology induced by chronic quetiapine exposure. By contrast, specific agonists of CB2R (JWH-133, AM 1241), but not its antagonist AM 630 exerted beneficial roles against quetiapine cardiotoxicity. The protective agents (AM 281, Rimonabant, AM 1241, and JWH-133) consistently inactivated the quetiapine-induced necroptosis signaling. Quetiapine bidirectionally regulates cannabinoid receptors and induces myocardial necroptosis, leading to cardiac toxic effects. Therefore, pharmacologic inhibition of CB1R or activation of CB2R represents promising therapeutic strategies against quetiapine-induced cardiotoxicity.

Dimethyl fumarate potentiates oncolytic virotherapy through NF-κB inhibition

Resistance to oncolytic virotherapy is frequently associated with failure of tumor cells to get infected by the virus. Dimethyl fumarate (DMF), a common treatment for psoriasis and multiple sclerosis, also has anticancer properties. We show that DMF and various fumaric and maleic acid esters (FMAEs) enhance viral infection of cancer cell lines as well as human tumor biopsies with several oncolytic viruses (OVs), improving therapeutic outcomes in resistant syngeneic and xenograft tumor models. This results in durable responses, even in models otherwise refractory to OV and drug monotherapies. The ability of DMF to enhance viral spread results from its ability to inhibit type I interferon (IFN) production and response, which is associated with its blockade of nuclear translocation of the transcription factor nuclear factor κB (NF-κB). This study demonstrates that unconventional application of U.S. Food and Drug Administration-approved drugs and biological agents can result in improved anticancer therapeutic outcomes.

Dimethyl fumarate attenuates lipopolysaccharide-induced mitochondrial injury by activating Nrf2 pathway in cardiomyocytes

AIMS

To determine whether dimethyl fumarate (DMF) can protect against lipopolysaccharide (LPS) -induced myocardial injury.

MAIN METHODS

H9c2 cells pretreated with or without DMF were stimulated with LPS. Cell viability and apoptosis were evaluated. Nrf2 and HO-1 expression were detected using Western blotting. Mitochondrial morphology, mitochondrial superoxide production were observed using confocal microscope. Mitochondrial respiration function was measured using Seahorse bioanalyzer.

KEY FINDINGS

(1) The cell viability decreased, LDH release and apoptosis increased in LPS- challenged H9c2 cells. DMF pretreatment brought a higher cell viability, and a lower LDH leakage and apoptosis than those of LPS group (P < 0.01). (2) DMF pretreatment resulted in an increased Nrf2 and HO-1 expression, and enhanced nuclear Nrf2 level in LPS-challenged cells (P < 0.01). (3) Nrf2-siRNA could inhibit DMF-induced enhancement of HO-1 expression and cell viability, and partly abolish DMF-induced reduction of LDH leakage and apoptosis. (4) ERK1/2 inhibitor PD98059 could not only prevent the DMF-induced enhancement of nuclear Nrf2 and HO-1, but also inhibit DMF-induced increase in cell viability. (5) Compared with LPS-challenged cells, DMF pretreatment caused a lower production of mitochondrial superoxide and a higher mitochondrial membrane potential, which could be abolished by Nrf2-siRNA. (6) DMF could attenuate LPS-induced mitochondrial fragmentation and improve mitochondrial respiration function by enhancement of the oxygen consumption rate of basal respiration and ATP production in LPS-challenged cells (P < 0.01).

SIGNIFICANCE

DMF protects cardiomyocytes against LPS-induced damage. ERK1/2-dependent activation of Nrf2/HO-1 pathway is responsible for DMF-induced cardioprotection via reduction of oxidative stress, improvement of mitochondrial morphology and energy metabolism.

Injectable pegylated niclosamide (polyethylene glycol-modified niclosamide) for cancer therapy

Niclosamide is an antihelminthic drug. Recent studies show that niclosamide exerts antitumor activity through inhibiting multiple signals including Wnt/β-catenin, mTORC1, signal transducer and activator of transcription 3, NF-κB, notch signals; however, the insolubility and poor bioavailability limits its potential clinic use, the aim of the present work is to synthesize an injectable pegylated niclosamide (polyethylene glycol-modified niclosamide) and investigate its antitumor activity in vitro and in vivo. The pegylated niclosamide (mPEG5000-Nic) was synthesized and the chemical structure was identified by Fourier transform infrared spectra and ¹ H nuclear magnetic resonance spectra. The antitumor activity was evaluated in CT26 and HCT116 colon cancer cells in vitro and nude mouse xenograft model of CT26 cells in vivo. The water solubility of niclosamide in mPEG5000-Nic was significantly increased. Niclosamide could be released from mPEG5000-Nic nanoparticles in PBS solution. mPEG5000-Nic inhibited the cell viability of CT26 and HCT116 cells in vitro. No animal death was observed in mice with intraperitoneal injection of mPEG5000-Nic (equivalent to 1000 mg/kg niclosamide) within 24 hr, indicating that mPEG5000-Nic was less toxic. In nude mouse, xenograft model of CT26 colon carcinoma, intraperitoneal injection of mPEG5000-Nic (equivalent to niclosamide 50 mg/kg) inhibited tumor growth but had no effect on animal body weight and heart, liver, kidney, and lung weight in vivo. Meanwhile, in the same model, intraperitoneal injection of the positive clinic drug 5-fluorouracil not only inhibited the tumor growth, but also reduced the animal body weight. Our study demonstrates that pegylated niclosamide is novel niclosamide delivery system with clinical perspective for cancer therapy.

Dimethyl fumarate suppresses hepatocellular carcinoma progression via activating SOCS3/JAK1/STAT3 signaling pathway

Dimethyl fumarate (DMF) is generally used to treat psoriasis and multiple sclerosis. In the present study, we aimed to investigate the effects of DMF on hepatocellular carcinoma progression and its mechanism of action. In vitro, cell viability was examined using CCK-8 assay; cell cycle was analyzed by flow cytometry; angiogenesis was detected using tube formation assay; and autophagic flux assay results were examined using fluorescence microscopy. We also used western blotting to explore the potential mechanisms. In vivo, tumor xenograft experiment was performed with nude mice, and liver function, renal function, and routine blood counts were assessed using biochemical tests. Dimethyl fumarate inhibited tumor growth and angiogenesis in hepatocellular carcinoma, both in vitro and in vivo. Dimethyl fumarate decreased autophagy in hepatocellular carcinoma cells. Treatment with DMF activated SOCS3, which led to repression of JAK1 and STAT3 phosphorylation. DMF inhibited cell proliferation, angiogenesis, and autophagy via activation of the SOCS3/JAK1/STAT3 signaling pathway. This finding may provide a novel approach for the treatment of hepatocellular carcinoma.

Hydrogen Sulfide Gas Exposure Induces Necroptosis and Promotes Inflammation through the MAPK/NF-κB Pathway in Broiler Spleen

Hydrogen sulfide (H2S) is one of the main pollutants in the atmosphere, which is a serious threat to human health. The decomposition of sulfur-containing organics in chicken houses could produce a large amount of H2S, thereby damaging poultry health. In this study, one-day-old broilers were selected and exposed to 4 or 20 ppm of H2S gas (0-3 weeks: 4 ± 0.5 ppm, 4-6 weeks: 20 ± 0.5 ppm). The spleen samples were collected immediately after the chickens were euthanized at 2, 4, and 6 weeks. The histopathological and ultrastructural observations showed obvious necrosis characteristics of H2S-exposed spleens. H2S exposure suppressed GSH, CAT, T-AOC, and SOD activities; increased NO, H2O2, and MDA content and iNOS activity; and induced oxidative stress. ATPase activities and the expressions of energy metabolism-related genes were significantly decreased. Also, the expressions of related necroptosis (RIPK1, RIPK3, MLKL, TAK1, TAB2, and TAB3) were significantly increased, and the MAPK pathway was activated. Besides, H2S exposure activated the NF-κB classical pathway and induced TNF-α and IL-1β release. Taken together, we conclude that H2S exposure induces oxidative stress and energy metabolism dysfunction; evokes necroptosis; activates the MAPK pathway, eventually triggering the NF-κB pathway; and promotes inflammatory response in chicken spleens.

Unraveling the Potential Role of Glutathione in Multiple Forms of Cell Death in Cancer Therapy

Glutathione is the principal intracellular antioxidant buffer against oxidative stress and mainly exists in the forms of reduced glutathione (GSH) and oxidized glutathione (GSSG). The processes of glutathione synthesis, transport, utilization, and metabolism are tightly controlled to maintain intracellular glutathione homeostasis and redox balance. As for cancer cells, they exhibit a greater ROS level than normal cells in order to meet the enhanced metabolism and vicious proliferation; meanwhile, they also have to develop an increased antioxidant defense system to cope with the higher oxidant state. Growing numbers of studies have implicated that altering the glutathione antioxidant system is associated with multiple forms of programmed cell death in cancer cells. In this review, we firstly focus on glutathione homeostasis from the perspectives of glutathione synthesis, distribution, transportation, and metabolism. Then, we discuss the function of glutathione in the antioxidant process. Afterwards, we also summarize the recent advance in the understanding of the mechanism by which glutathione plays a key role in multiple forms of programmed cell death, including apoptosis, necroptosis, ferroptosis, and autophagy. Finally, we highlight the glutathione-targeting therapeutic approaches toward cancers. A comprehensive review on the glutathione homeostasis and the role of glutathione depletion in programmed cell death provide insight into the redox-based research concerning cancer therapeutics.

Antitumor activity of Raddeanin A is mediated by Jun amino-terminal kinase activation and signal transducer and activator of transcription 3 inhibition in human osteosarcoma

Osteosarcoma is the most common primary malignant bone tumor. Raddeanin A (RA) is an active oleanane‐type triterpenoid saponin extracted from the traditional Chinese herb Anemone raddeana Regel that exerts antitumor activity against several cancer types. However, the effect of RA on osteosarcoma remains unclear. In the present study, we showed that RA inhibited proliferation and induced apoptosis of osteosarcoma cells in a dose‐ and time‐dependent way in vitro and in vivo. RA treatment resulted in excessive reactive oxygen species (ROS) generation and JNK and ERK1/2 activation. Apoptosis induction was evaluated by the activation of caspase‐3, caspase‐8, and caspase‐9 and poly‐ADP ribose polymerase (PARP) cleavage. RA‐induced cell death was significantly restored by the ROS scavenger glutathione (GSH), the pharmacological inhibitor of JNK SP600125, or specific JNK knockdown by shRNA. Additionally, signal transducer and activator of transcription 3 (STAT3) activation was suppressed by RA in human osteosarcoma, and this suppression was restored by GSH, SP600125, and JNK‐shRNA. Further investigation showed that STAT3 phosphorylation was increased after JNK knockdown. In a tibial xenograft tumor model, RA induced osteosarcoma apoptosis and notably inhibited tumor growth. Taken together, our results show that RA suppresses proliferation and induces apoptosis by modulating the JNK/c‐Jun and STAT3 signaling pathways in human osteosarcoma. Therefore, RA may be a promising candidate antitumor drug for osteosarcoma intervention.

Niclosamide ethanolamine induces trachea relaxation and inhibits proliferation and migration of trachea smooth muscle cells

Our previous study found that the anthelmintic drug niclosamide relaxed the constricted arteries and inhibited proliferation and migration of vascular smooth muscle cells. Here, we investigated the effect of niclosamide ethanolamine (NEN) on trachea function and the proliferation and migration of trachea smooth muscle cells. Isometric tension of trachea was recorded by multi-channel myograph system. The cell proliferation was detected by using BrdU cell proliferation assay. The cell migration ability was evaluated by using scratch assay. The protein level was measured by using western blot technique. Acute treatment with NEN dose-dependently relaxed acetylcholine chloride (Ach)- and High K⁺ physiological salt solution (KPSS)-induced constriction of mice trachea. Pre-treatment with NEN inhibited Ach- and KPSS-induced constriction of mice trachea. NEN treatment inhibited proliferation of human bronchial smooth muscle cells (HBSMCs), inhibited migration of HBSMCs and rat primary trachea smooth muscle cells. NEN treatment activated adenosine monophosphate activated protein kinase (AMPK) activity and inhibited signal transducer and activator of transcription 3 (STAT3) activity in HBSMCs. In conclusion, niclosamide ethanolamine induces trachea relaxation and inhibits proliferation and migration of trachea smooth muscle cells, indicating that niclosamide might be a potential drug for chronic asthma treatment.

The different response of cardiomyocytes and cardiac fibroblasts to mitochondria inhibition and the underlying role of STAT3

Cardiomyocyte loss and cardiac fibrosis are the main characteristics of cardiac ischemia and heart failure, and mitochondrial function of cardiomyocytes is impaired in cardiac ischemia and heart failure, so the aim of this study is to identify fate variability of cardiomyocytes and cardiac fibroblasts with mitochondria inhibition and explore the underlying mechanism. The mitochondrial respiratory function was measured by using Oxygraph-2k high-resolution respirometry. The STAT3 expression and activity were evaluated by western blot. Cardiomyocytes and cardiac fibroblasts displayed different morphology. The mitochondrial respiratory function and the expressions of mitochondrial complex I, II, III, IV, and V of cardiac fibroblasts were lower than that of cardiomyocytes. Mitochondrial respiratory complex I inhibitor rotenone and H₂O₂ (100 µM, 4 h) treatment induced cell death of cardiomyocyte but not cardiac fibroblasts. The function of complex I/II was impaired in cardiomycytes but not cardiac fibroblasts stimulated with H₂O₂ (100 µM, 4 h) and in ischemic heart of mice. Rotenone and H₂O₂ (100 µM, 4 h) treatment reduced STAT3 expression and activity in cardiomyocytes but not cardiac fibroblasts. Inhibition of STAT3 impaired mitochondrial respiratory capacity and exacerbated H₂O₂-induced cell injury in cardiomycytes but not significantly in cardiac fibroblasts. In conclusion, the different susceptibility of cardiomyocytes and cardiac fibroblasts to mitochondria inhibition determines the cell fate under the same pathological stimuli and in which STAT3 plays a critical role.

Dimethyl fumarate, a two-edged drug: Current status and future directions

Dimethyl fumarate (DMF) is a fumaric acid ester registered for the treatment of relapsing-remitting multiple sclerosis (RRMS). It induces protein succination leading to inactivation of cysteine-rich proteins. It was first shown to possess cytoprotective and antioxidant effects in noncancer models, which appeared related to the induction of the nuclear factor erythroid 2 (NF-E2)-related factor 2 (NRF2) pathway. DMF also displays antitumor activity in several cellular and mice models. Recently, we showed that the anticancer mechanism of DMF is dose-dependent and is paradoxically related to the decrease in the nuclear translocation of NRF2. Some other studies performed indicate also the potential role of DMF in cancers, which are dependent on the NRF2 antioxidant and cellular detoxification program, such as KRAS-mutated lung adenocarcinoma. It, however, seems that DMF has multiple biological effects as it has been shown to also inhibit the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), thus blocking downstream targets that may be involved in the development and progression of inflammatory cascades leading to various disease processes, including tumors, lymphomas, diabetic retinopathy, arthritis, and psoriasis. Herein, we present the current status and future directions of the use of DMF in various diseases models with particular emphases on its targeting of specific intracellular signal transduction cascades in cancer; to shed some light on its possible mode of action.

The anti-inflammatory and anti-oxidative effects of conbercept in treatment of macular edema secondary to retinal vein occlusion

To investigate the effects of conbercept on inflammatory and oxidative response in macular edema secondary to retinal vein occlusion (RVO-ME). Retinal microvasculature were detected by optical coherence tomographic angiography (OCTA). The inflammation related factors including prostaglandin E1 (PGE1), prostaglandin E2 (PGE2), prostaglandin F2a (PGF2a), intercellular cell adhesion molecule-1 (ICAM-1) and macrophage inflammatory protein-1 (MIP-1) were determined in human and mice with RVO-ME. OCTA images showed that capillary non-perfusion, enlargement of the foveal avascular zone, telangiectatic vessels and some forms of intraretinal edema in RVO-ME and all these were alleviated by conbercept treatment. PGE1, PGE2, PGF2a, ICAM-1 and MIP-1 in aqueous fluid extracted from RVO-ME patients was significantly increased compared with non-RVO subjects, intravitreal injection of conbercept partly reduced ICAM-1 and MIP-1 levels but not PGE1, PGE2 and PGF2a. The glutathione level was reduced in aqueous fluid extracted from RVO-ME patients but was restored after conbercept treatment. The inflammation, angiogenesis and ROS generation was increased in RVO-ME mice, conbercept partly inhibited these effects. Mechanistically, conbercept inhibited vascular endothelial growth factor (VEGF), ICAM-1, MIP-1, NOX-1 and NOX-4 protein expressions, but not PGE1, PGE2 and PGF2a expressions. Conbercept alleviates RVO-ME through inhibiting inflammation, angiogenesis and oxidative responses. These findings further reveals the molecular mechanism of conbercept for treatment of RVO-ME.

Mitochondrial uncoupler BAM15 inhibits artery constriction and potently activates AMPK in vascular smooth muscle cells

Our previous studies found that mitochondrial uncouplers CCCP and niclosamide inhibited artery constriction and the mechanism involved AMPK activation in vascular smooth muscle cells. BAM15 is a novel type of mitochondrial uncoupler. The aim of the present study is to identify the vasoactivity of BAM15 and characterize the BAM15-induced AMPK activation in vascular smooth muscle cells (A10 cells). BAM15 relaxed phenylephrine (PE)-induced constricted rat mesenteric arteries with intact and denuded endothelium. Pretreatment with BAM15 inhibited PE-induced constriction of rat mesenteric arteries with intact and denuded endothelium. BAM15, CCCP, and niclosamide had the comparable IC₅₀ value of vasorelaxation in PE-induced constriction of rat mesenteric arteries. BAM15 was less cytotoxic in A10 cells compared with CCCP and niclosamide. BAM15 depolarized mitochondrial membrane potential, induced mitochondrial fission, increased mitochondrial ROS production, and increased mitochondrial oxygen consumption rate in A10 cells. BAM15 potently activated AMPK in A10 cells and the efficacy of BAM15 was stronger than that of CCCP, niclosamide, and AMPK positive activators metformin and AICAR. In conclusion, BAM15 activates AMPK in vascular smooth muscle cells with higher potency than that of CCCP, niclosamide and the known AMPK activators metformin and AICAR. The present work indicates that BAM15 is a potent AMPK activator.

Cancer Risk in Patients with Multiple Sclerosis: Potential Impact of Disease-Modifying Drugs

In the 1990s, the first disease-modifying therapies (DMTs) for multiple sclerosis (MS) were injectable immunomodulatory (IM) drugs, including four different interferon-β preparations and glatiramer acetate. Since 2000, more than 15 immunosuppressant (IS) drugs have been used, with a more or less specific action on inflammation. These include monoclonal antibodies targeting CTL4, the integrin receptor, the interleukin (IL)-2 receptor, CD19, CD20, CD52, and the sphingosine 1 phosphate family. The association between MS and cancer has long been investigated but has led to conflicting results. No studies have reported an increased risk of cancer after long-term exposure to IM. Several reports suggest an increase in cancer risk among MS patients treated with IS such as mitoxantrone, azathioprine and cyclophosphamide. Because of their action on the immune system, and due to a lack of available long-term data, a special warning of the potential risk of cancer accompanies the use of recent IS such as cladribine, fingolimod, natalizumab or alemtuzumab. In most studies, factors such as diet, smoking, solar radiation, and hormone therapy, all of which influence cancer risk, have not been considered. For fingolimod, natalizumab, alemtuzumab, dimethyl fumarate, teriflunomide, daclizumab and ocrelizumab, risk management plans outlined by regulatory agencies are mandatory. They allow prospective detection of some red flags, in particular those for the increased risk of cancer. We review the current evidence behind the increased risk of malignancy in MS patients receiving DMTs, and provide an overview of the DMTs that are currently in use and those in clinical trials. The known risks and benefits of these therapies will be considered.

Colorectal carcinogenesis: Insights into the cell death and signal transduction pathways: A review

Colorectal carcinogenesis (CRC) imposes a major health burden in developing countries. It is the third major cause of cancer deaths. Despite several treatment strategies, novel drugs are warranted to reduce the severity of this disease. Adenomatous polyps in the colon are the major culprits in CRC and found in 45% of cancers, especially in patients 60 years of age. Inflammatory polyps are currently gaining attention in CRC, and a growing body of evidence denotes the role of inflammation in CRC. Several experimental models are being employed to investigate CRC in animals, which include the APC^min/+ mouse model, Azoxymethane, Dimethyl hydrazine, and a combination of Dextran sodium sulphate and dimethyl hydrazine. During CRC progression, several signal transduction pathways are activated. Among the major signal transduction pathways are p53, Transforming growth factor beta, Wnt/β-catenin, Delta Notch, Hippo signalling, nuclear factor erythroid 2-related factor 2 and Kelch-like ECH-associated protein 1 pathways. These signalling pathways collaborate with cell death mechanisms, which include apoptosis, necroptosis and autophagy, to determine cell fate. Extensive research has been carried out in our laboratory to investigate these signal transduction and cell death mechanistic pathways in CRC. This review summarizes CRC pathogenesis and the related cell death and signal transduction pathways.

Characterizations of mitochondrial uncoupling induced by chemical mitochondrial uncouplers in cardiomyocytes

Induction of mild mitochondrial uncoupling is protective in a variety of disorders; however, it is unclear how to recognize the mild mitochondrial uncoupling induced by chemical mitochondrial uncouplers. The aim of the present study is to identify the pharmacological properties of mitochondrial uncoupling induced by mitochondrial uncouplers in cardiomyocytes. Neonatal rat cardiomyocytes were cultured. Protein levels were measured by using western blot technique. The whole cell respiratory function was determined by using high-resolution respirometry. The typical types of chemical mitochondrial uncouplers, carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), niclosamide, and BAM15, induced biphasic change of STAT3 activity in cardiomyocytes, activating STAT3 at low dose and inhibiting STAT3 at high dose, though the dose range of these drugs was distinct. Low-dose uncouplers induced STAT3 activation through the mild increase of mitochondrial ROS (mitoROS) generation and the subsequent JAK/STAT3 activation in cardiomyocytes. However, high-dose uncouplers induced inhibition of STAT3, decrease of ATP production, and cardiomyocyte death. High-dose uncouplers induced STAT3 inhibition through the excessive mitoROS generation and the decreased ATP -induced AMPK activation. Low-dose mitochondrial uncouplers attenuated doxorubicin (DOX)-induced STAT3 inhibition and cardiomyocyte death, and activated STAT3 contributed to the cardioprotection of low-dose mitochondrial uncouplers. Uncoupler-induced mild mitochondrial uncoupling in cardiomyocytes is characterized by STAT3 activation and ATP increase whereas excessive mitochondrial uncoupling is characterized by STAT3 inhibition, ATP decrease and cell injury. Development of mitochondrial uncoupler with optimal dose window of inducing mild uncoupling is a promising strategy for heart protection.

Oridonin enhances the cytotoxicity of 5-FU in renal carcinoma cells by inducting necroptotic death

BACKGROUND

5-fluorouracil (5-FU) is widely used for the treatment of renal carcinoma. However, drug resistance remains the reason for failure of chemotherapy. Oridonin, extracted from Chinese herb medicine, displays anti-tumor effect in several types of cancer. Whether oridonin could enhance the effect of 5-FU in renal carcinoma has not been studied.

METHODS

786-O cells were used in the current study. Cell death was measured by MTT assay or live- and dead-cell staining assay. Glutathione (GSH) level was examined by ELISA. Necroptosis was identified by protein levels of receptors interaction protein-1 (RIP-1) and RIP-3, lactate dehydrogenase (LDH) and high mobility group box-1 protein (HMGB1) release, and poly [ADP-ribose] polymerase-1 (Parp-1) activity. Using a xenograft assay in nude mice, we tested the anti-tumor effects of the oridonin combined with 5-FU.

RESULTS

5-FU only induced apoptosis in 786-O cells. Oridonin activated both apoptosis and necroptosis in 786-O cells. Oridonin-induced necroptosis was reversed by addition of GSH or its precursorN-acetylcysteine (NAC). Oridonin-induced necroptosis was associated by activated JNK, p38, and ERK in 786-O cells, which were abolished by GSH or NAC treatment. However, JNK, p38, and ERK inhibitors showed no effect on oridonin induced-cell death. GSH or NAC treatment partly abolished the synergistic effects of oridonin and 5-FU on cell death. Oridonin enhanced the cytotoxicity of 5-FU both in vitro and in vivo.

CONCLUSION

Oridonin enhances the cytotoxicity of 5-FU in renal cancer cells partially through inducing necroptosis, providing evidence of using necroptosis inducers in combination with chemotherapeutic agents for cancer treatment.

Mononuclear cell transcriptome changes associated with dimethyl fumarate in MS

Objective

To identify short-term changes in gene expression in peripheral blood mononuclear cells (PBMCs) associated with treatment response to dimethyl fumarate (DMF, Tecfidera) in patients with relapsing-remitting MS (RRMS).

Methods

Blood samples were collected from 24 patients with RRMS (median Expanded Disability Status Scale score, 2.0; range 1–7) at baseline, 6 weeks, and 15 months after the initiation of treatment with DMF (BG-12; Tecfidera). Seven healthy controls were also recruited, and blood samples were collected over the same time intervals. PBMCs were extracted from blood samples and sequenced using next-generation RNA sequencing. Treatment responders were defined using the composite outcome measure “no evidence of disease activity” (NEDA-4). Time-course and cross-sectional differential expression analyses were performed to identify transcriptomic markers of treatment response.

Results

Treatment responders (NEDA-4 positive, 8/24) over the 15-month period had 478 differentially expressed genes (DEGs) 6 weeks after the start of treatment. These were enriched for nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and inhibition of nuclear factor κB (NFκB) pathway transcripts. For patients who showed signs of disease activity, there were no DEGs at 6 weeks relative to their (untreated) baseline. Contrasting transcriptomes expressed at 6 weeks with those at 15 months of treatment, 0 and 1,264 DEGs were found in the responder and nonresponder groups, respectively. Transcripts in the nonresponder group (NEDA-4 negative, 18/24) were enriched for T-cell signaling genes.

Conclusion

Short-term PBMC transcriptome changes reflecting activation of the Nrf2 and inhibition of NFκB pathways distinguish patients who subsequently show a medium-term treatment response with DMF. Relative stabilization of gene expression patterns may accompany treatment-associated suppression of disease activity.

miR-200a-5p regulates myocardial necroptosis induced by Se deficiency via targeting RNF11

Necroptosis has been discovered as a new paradigm of cell death and may play a key role in heart disease and selenium (Se) deficiency. Hence, we detected the specific microRNA (miRNA) in response to Se-deficient heart using microRNAome analysis. For high-throughput sequencing using Se-deficient chicken cardiac tissue, we selected miR-200a-5p and its target gene ring finger protein 11 (RNF11) based on differential expression in cardiac tissue and confirmed the relationship between miR-200a-5p and RNF11 by dual luciferase reporter assay and real-time quantitative PCR (qRT-PCR) in cardiomyocytes. We further explored the function of miR-200a-5p and observed that overexpression of miR-200a-5p spark the receptor interacting serine/threonine kinase 3 (RIP3)-dependent necroptosis in vivo and in vitro. To understand whether miR-200a-5p and RNF11 are involved in the RIP3-dependent necroptosis pathway, we presumed that oxidative stress, inflammation response and the mitogen-activated protein kinase (MAPK) pathway might trigger necroptosis. Interestingly, necroptosis trigger, z-VAD-fmk, failed to induce necroptosis but enhanced cell survival against necrosis in cardiomyocytes with knockdown of miR-200a-5p. Our present study provides a new insight that the modulation of miR-200a-5p and its target gene might block necroptosis in the heart, revealing a novel myocardial necrosis regulation model in heart disease.

Dithiolethione ACDT suppresses neuroinflammation and ameliorates disease severity in experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is an autoimmune disorder characterized by the central nervous system (CNS) infiltration of myelin-specific pathogenic T cells followed by brain inflammation in association with demyelination. Similarly, experimental autoimmune encephalomyelitis (EAE), the animal model of MS, also exhibits increased CNS infiltration of pathogenic T cells, including Th1 and Th17, leading to detrimental effects of neuroinflammation and demyelination. We previously reported that 3H-1,2-dithiole-3-thione (D3T), the structurally-simplest of the sulfur-containing dithiolethiones, exerted a promising therapeutic effect in EAE. In the current study we report that 5-Amino-3-thioxo-3H-(1,2)dithiole-4-carboxylic acid ethyl ester (ACDT), a substituted derivative of D3T, exhibits anti-inflammatory properties in EAE. ACDT, administered post immunization, delayed disease onset and reduced disease severity in chronic C57BL/6 EAE, and ACDT, administered during disease remission, suppressed disease relapse in relapsing-remitting SJL/J EAE. Further analysis of the cellular and molecular mechanisms underlying the protective effects of ACDT in EAE revealed that ACDT inhibited pathogenic T cell infiltration, suppressed microglia activation, repressed neurotoxic A1 astrocyte generation, lessened blood-brain barrier disruption, and diminished MMP3/9 production in the CNS of EAE. In summary, we demonstrate that ACDT suppresses neuroinflammation and ameliorates disease severity in EAE through multiple cellular mechanisms. Our findings suggest the potential of developing ACDT as a novel therapeutic agent for the treatment of MS/EAE.

Niclosamide inhibits vascular smooth muscle cell proliferation and migration and attenuates neointimal hyperplasia in injured rat carotid arteries

BACKGROUND AND PURPOSE

The anti-helminthic drug niclosamide regulates multiple cellular signals including STAT3, AMP-activated protein kinase (AMPK), Akt, Wnt/β-catenin and mitochondrial uncoupling which are involved in neointimal hyperplasia. Here we have examined the effects of niclosamide on vascular smooth muscle cell proliferation, migration and neointimal hyperplasia and assessed the potential mechanisms.

EXPERIMENTAL APPROACH

Cell migration was measured by using wound-induced migration assay and Boyden chamber assay. Protein levels were measured by using Western blot technique. Neointimal hyperplasia in vivo was induced in rats by balloon injury to the carotid artery.

KEY RESULTS

Niclosamide treatment inhibited serum-induced (15% FBS) and PDGF-BB-induced proliferation and migration of vascular smooth muscle cells (A10 cells). Niclosamide showed no cytotoxicity at anti-proliferative concentrations, but induced cell apoptosis at higher concentrations. Niclosamide treatment inhibited serum-induced (15% FBS) and PDGF-BB-induced STAT3 activation (increased protein levels of p-STAT3 at Tyr⁷⁰⁵ ) but activated AMPK, in A10 cells. Niclosamide exerted no significant effects on β-catenin expression and the activities of ERK1/2 and Akt in A10 cells. Injection (i.p.) of soluble pegylated niclosamide (PEG5000-niclosamide) (equivalent to niclosamide 25 mg·kg^-1 ) attenuated neointimal hyperplasia following balloon-injury in rat carotid arteries in vivo.

CONCLUSIONS AND IMPLICATIONS

Niclosamide inhibited vascular smooth muscle cell proliferation and migration and attenuated neointimal hyperplasia in balloon-injured rat carotid arteries through a mechanism involving inhibition of STAT3.

Pyrroloquinoline quinone induces chondrosarcoma cell apoptosis by increasing intracellular reactive oxygen species

Pyrroloquinoline quinone (PQQ) has been reported to contribute to cancer cell apoptosis and death; however, little is known of its underlying mechanisms. The present study was designed to investigate the role of PQQ in chondrosarcoma cell apoptosis and the underlying mechanism. A cell cytotoxicity assay was used to detect cell death; flow cytometry analysis was also performed to determine cell apoptosis and intracellular reactive oxygen species (ROS). Biochemical methods were employed to detect the activity and the expression of superoxide dismutase (SOD)1, SOD2 and glutathione. The present study also examined the effect on tumorigenesis in vivo. The results demonstrated that the apoptosis of SW1353 cells induced by PQQ increased in a concentration- and time-dependent manner, which may be attributable to the accumulation of intracellular ROS. In the in vivo experiments, PQQ inhibited proliferation and promoted apoptosis, increased ROS levels and caused DNA damage in transplanted cells. Taken together, the findings of the present study confirmed that PQQ induced apoptosis in human chondrosarcoma SW1353 cells and transplanted cells, by increasing intracellular ROS and reducing the ability of scavenging oxygen free radicals.

The putative interplay between DJ-1/NRF2 and Dimethyl Fumarate: A potentially important pharmacological target

Recent research has outlined that Dimethyl Fumarate (DMF) functions as a gene regulator via multiple pathways, critical among which is the NRF2 cytoprotective cascade. PARK7/DJ-1 is a multifunctional protein that acts as a redox sensor and effector of multiple cytoprotective pathways, including NRF2. Specifically, it prevents the association of NRF2 with its inhibitor KEAP1, allowing NRF2 to enter the nucleus and mediate cytoprotective and antioxidant cascades. It is our hypothesis that while the NRF2-KEAP1 inhibitory complex is reported the main pharmacological target for DMF's NRF dependent functions, no study to date has explored the effects of DMF on DJ-1's expression, and vice-versa, the possibility of a regulatory inadequacy in the upstream, oxidant-responsive DJ-1 activator of the NRF2 cascade.

Necroptosis in tumorigenesis, activation of anti-tumor immunity, and cancer therapy

While the mechanisms underlying apoptosis and autophagy have been well characterized over recent decades, another regulated cell death event, necroptosis, remains poorly understood. Elucidating the signaling networks involved in the regulation of necroptosis may allow this form of regulated cell death to be exploited for diagnosis and treatment of cancer, and will contribute to the understanding of the complex tumor microenvironment. In this review, we have summarized the mechanisms and regulation of necroptosis, the converging and diverging features of necroptosis in tumorigenesis, activation of anti-tumor immunity, and cancer therapy, as well as attempts to exploit this newly gained knowledge to provide therapeutics for cancer.

Subchronic methionine load induces oxidative stress and provokes biochemical and histological changes in the rat liver tissue

The aim of this study was to assess the effects of L-cysteine (Cys) (7 mg/kg) and N-acetyl-L-cysteine (NAC) (50 mg/kg) in the rat liver caused by subchronic i.p. application of methionine (Met) (0.8 mmol/kg) during 21 days. Malondialdehyde (MDA) concentration, glutathione content (GSH), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and acetylcholinesterase (AchE) activities were determined in the liver tissue and activities of liver enzymes (AST, ALT, ALP, and GGT) and concentrations of total proteins and albumin were determinated in plasma/serum. Catalase, superoxide dismutase, and acetylcholinesterase activities were increased by Cys and NAC. Met caused periportal mononuclear infiltration and rare focal necrosis of hepatocytes. In Cys- and NAC-supplemented groups, intracellular edema and microvesicular fatty changes without necrosis were noticed. We observed decrease of AST, ALT, and ALP activity in the methionine-treated group. Our results indicate that Cys and NAC application can increase activity of antioxidative enzymes and prevent intensive histological changes in liver in condition of subchronic methionine exposure.

Necrostatin-1 protects C2C12 myotubes from CoCl2-induced hypoxia

Necrostatin-1 (Nec-1) is a selective and potent allosteric inhibitor of necroptosis by specifically inhibiting the activity of receptor-interacting protein (RIP) 1 kinase. The aim of the present study was to determine the effect of Nec-1 on an anoxia model comprising mouse skeletal C2C12 myotubes. In the present study, a hypoxic mimetic reagent, cobalt chloride (CoCl₂), was used to induce hypoxia in C2C12 myotubes. The cytotoxic effects of CoCl₂-induced hypoxia were determined by a Cell Counting kit-8 assay and flow cytometry. Transmission electron microscopy (TEM) was used to characterize the morphological characteristics of dead cells at the ultrastructural level. To clarify the signaling pathways in CoCl₂-mediated cell death, the expression levels of RIP1, RIP3, extracellular signal-regulated kinase (ERK)1/2, hypoxia-inducible factor (HIF)-1α and B cell lymphoma-2 adenovirus E1B 19-kDa interacting protein 3 (BNIP3) were investigated by western blotting. Oxidative stress was determined using 2′,7′-dichlorofluorescin diacetate to measure intracellular reactive oxygen species (ROS) and the fluorescent dye JC-1 was used to measure mitochondrial membrane potential (Δψm). The results showed that the ratios of apoptotic and necrotic C2C12 cells were increased following CoCl₂ treatment, typical necroptotic morphological characteristics were able to observe by TEM, whereas Nec-1 exhibited a protective effect against CoCl₂-induced oxidative stress. Treatment with Nec-1 significantly decreased the levels of RIP1, p-ERK1/2, HIF-1α, BNIP3 and ROS induced by CoCl₂, and promoted C2C12 differentiation. Nec-1 reversed the CoCl₂-induced decrease in mitochondrial membrane potential. Together, these findings suggested that Nec-1 protected C2C12 myotubes under conditions of CoCl₂-induced hypoxia.

Reactive oxygen species and colorectal cancer

Colorectal cancer (CRC) has become the fourth leading cause of cancer-related death in the worldwide. It is urgent to find more effective therapeutic strategies for it. Reactive oxygen species (ROS) play multiple roles in normal cellular physiology processes. Thus, a certain level of ROS is essential to keep normal cellular function. However, the accumulation of ROS shows dual roles for cells, which is mainly dependent on the concentration of ROS, the origin of the cancer cell and the activated signaling pathways during tumor progression. In general, moderate level of ROS leads to cell damage, DNA mutation and inflammation, which promotes the initiation and development of cancer. Excessive high level of ROS induces cancer cell death, showing an anti-cancer role. ROS are commonly higher in CRC cells than their normal counterpart cells. Therefore, it is possible that ROS induce cell death in cancer cells while not affecting the normal cells, demonstrating lower side effects. Besides, ROS also play a role in tumor microenvironment and drug resistance. These multiple roles of ROS make them a promising therapeutic target for cancer. To explore potential ROS-target therapies against CRC, it is worth to comprehensively understanding the role of ROS in CRC and therapy. In this review, we mainly discuss the strategies of ROS in CRC therapy, including direct CRC cell target and indirect tumor environment target. In addition, the influences of ROS in drug resistance will also been discussed.

Dimethyl fumarate is highly cytotoxic in KRAS mutated cancer cells but spares non-tumorigenic cells

KRAS mutation, one of the most common molecular alterations observed in adult carcinomas, was reported to activate the anti-oxidant program driven by the transcription factor NRF2 (Nuclear factor-erythroid 2-related factor 2). We previously observed that the antitumoral effect of Dimethyl fumarate (DMF) is dependent of NRF2 pathway inhibition. We used in vitro methods to examine the effect of DMF on cell death and the activation of the NRF2/DJ-1 antioxidant pathway. We report here that DMF is preferentially cytotoxic against KRAS mutated cancer cells. This effect was observed in patient-derived cancer cell lines harbouring a G12V KRAS mutation, compared with cell lines without such a mutation. In addition, KRAS*G12V over-expression in the human Caco-2 colon cancer cell line significantly promoted DMF-induced cell death, as well as DMF-induced- reactive oxygen species (ROS) formation and -glutathione (GSH) depletion. Moreover, in contrast to malignant cells, our data confirms that the same concentration of DMF has no significant cytotoxic effects on non-tumorigenic human ARPE-19 retinal epithelial, murine 3T3 fibroblasts and primary mice bone marrow cells; but is rather associated with NRF2 activation, decreased ROS and increased GSH levels. Furthermore, DJ-1 down-regulation experiments showed that this protein does not play a protective role against NRF2 in non-tumorigenic cells, as it does in malignant ones. This, interestingly, could be at the root of the differential effect of DMF observed between malignant and non-tumorigenic cells. Our results suggest for the first time that the dependence on NRF2 observed in mutated KRAS malignant cells makes them more sensitive to the cytotoxic effect of DMF, which thus opens up new prospects for the therapeutic applications of DMF.

Achyranthes bidentata polypeptide protects dopaminergic neurons from apoptosis in Parkinson's disease models both in vitro and in vivo

BACKGROUND AND PURPOSE

Parkinson's disease (PD) is a neurodegenerative disorder closely associated with dopaminergic neuron loss. It is well documented that Achyranthes bidentata polypeptides (ABPP) are potent neuroprotective agents in several kinds of neurons. Therefore, we proposed that ABPP might play a beneficial role against PD by protecting dopaminergic neurons from apoptosis.

EXPERIMENTAL APPROACH

SH-SY5Y cells and primary rat dopaminergic neurons were pretreated with ABPP fraction k (ABPPk), a purified fraction of ABPP, and then the cells were exposed to 1-methyl-4-phenylpyridinium iodide (MPP⁺ ) to induce apoptosis. Cell viability, LDH activity, a Tunel assay and protein levels of Bcl-2 and Bax were analysed. In an in vivo PD model induced by MPTP, ABPPk was intranasally delivered to mice. Behavioural tests, immunohistochemistry, immunostaining, Nissl staining, qRT-PCR and Western blot were employed to evaluate the potential effects of ABPPk on PD in mice.

KEY RESULTS

The application of ABPPk markedly enhanced the viability of SH-SY5Y cells and primary dopaminergic neurons treated with neurotoxic agent MPP⁺ . In an in vivo MPTP-induced PD model, ABPPk significantly improved behavioural performances and prevented tyrosine hydroxylase loss in the substantia nigra pars compacta and striatum. Furthermore, we showed that MPTP-induced astrocyte and microglia activation were largely attenuated by ABPPk, leading to low levels of neuroinflammation and a downregulation of the apoptotic signalling pathway.

CONCLUSION AND IMPLICATIONS

Taken together, our data show that ABPPk protects dopaminergic neurons from apoptosis, suggesting that ABPPk might be an effective intervention for treating the neuron loss associated with disorders such as PD.

ROS Modulator Molecules with Therapeutic Potential in Cancers Treatments

Reactive Oxygen Species (ROS) are chemically reactive chemical species containing oxygen. The redox status of a cell is function of the relative concentrations of oxidized and reduced forms of proteins, enzymes, ROS, molecules containing thiol and other factors. In the organism, the redox balance is based on the generation and elimination of ROS produced by endogenous and exogenous sources. All living organisms must maintain their redox equilibrium to survive and proliferate. Enzymatic and molecular pathways control ROS levels tightly but differentially depending on the type of cell. This review is an overview of various molecules that modulate ROS production/detoxification and have a synergistic action with the chemotherapies to kill cancer cells while preserving normal cells to avoid anticancer drugs side effects, allowing a better therapeutic index of the anticancer treatments.

GDF11/BMP11 activates both smad1/5/8 and smad2/3 signals but shows no significant effect on proliferation and migration of human umbilical vein endothelial cells

GDF11/BMP11, a member of TGF-β superfamily, was reported to rejuvenate heart, skeletal muscle and blood vessel architecture in aged mice. However, the rejuvenative effects of GDF11 were questioned recently. Here, we investigated the effects of GDF11 on smad and non-smad signals in human umbilical vein endothelial cells (HUVECs) and the effects of GDF11 on proliferation and migration of HUVECs and primary rat aortic endothelial cells (RAECs). GDF11 factor purchased from two different companies (PeproTech and R&D Systems) was comparatively studied. Western blot was used to detect the protein expressions. The cell viability and migration were examined by using MTT and wound healing assays. Results showed that GDF11 activated both smad1/5/8 and smad2/3 signals in HUVECs. GDF11 increased protein expression of NADPH oxidase 4(NOX4) in HUVECs. GDF11 showed no significant effect on the protein level of p38, p-p38, ERK, p-ERK, Akt, p-Akt (Ser473) and p-Akt(Thr308), but increased the protein level of p-JNK and p-AMPK in HUVECs, and these increases were inhibited by antioxidant mitoTEMPO treatment. GDF11 slightly increased cell viability after short-term treatment and slightly decreased cell viability after long-term treatment. GDF11 showed no significant effect on cell proliferation and migration. These data indicated that the notion of GDF11 as a rejuvenation-related factor for endothelial cells needs to be cautious.

Decreased prevalence of cancer in patients with multiple sclerosis: A case-control study

BACKGROUND

Studies of cancer prevalence have produced conflicting results concerning the relative risk of overall and specific sub-types of cancer in patients with multiple sclerosis (MS). Contemporary controls and information on tobacco use and alcohol consumption are generally missing from previous studies.

OBJECTIVES

To evaluate lifetime cancer prevalence in a large cohort of MS patients relative to appropriate controls.

METHODS

We conducted a case-control study, using a postal survey of a cohort of MS patients. Of the 1574 questionnaires sent, 1107 could be used for statistical analysis. Data from 1568 controls were prospectively collected using the same self-administered survey among consecutive out-patients in a single neurology department. Propensity scores matched on age, gender, and history of smoking and alcohol consumption were calculated.

RESULTS

Among the MS patients, 7.32% had ever presented with a cancer, whereas 12,63% of the controls had, leading to a bootstrap matched odds ratio (OR) of 0.63; 95% CI 0.57-0.70. Although only exploratory, the use of DMT (immunomodulators or immunosupressants) did not appear to increase this risk (p = 0.42). The disease course also did not affect cancer prevalence.

CONCLUSION

MS was associated with a reduced overall cancer risk.