Effects of selected food factors with chemopreventive properties on combined lipopolysaccharide- and interferon-gamma-induced IkappaB degradation in RAW264.7 macrophages

Zerumbone, a tropical ginger sesquiterpene, inhibits colon and lung carcinogenesis in mice

Zerumbone (ZER), present in subtropical ginger Zingiber zerumbet Smith, possesses anti-growth and anti-inflammatory properties in several human cancer cell lines. ZER also down-regulates the cyclooxygenase-2 and inducible nitric oxide synthase expression via modulation of nuclear factor (NF)-kappaB activation in cell culture systems. These findings led us to investigate whether ZER is able to inhibit carcinogenesis in the colon and lung, using 2 different preclinical mouse models. In Exp. 1, a total of 85 male ICR mice were initiated using a single intraperitoneal (i.p.) injection with azoxymethane (AOM, 10 mg/kg bw) and promoted by 1.5% dextran sulfate sodium (DSS) in drinking water for 7 days for rapid induction of colonic neoplasms. Animals were then fed the diet containing 100, 250 or 500 ppm ZER for 17 weeks. In Exp. 2, a total of 50 female A/J mice were given a single i.p. injection of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (10 micromol/mouse) to induce lung proliferative lesions. They were then fed the diet mixed with 100, 250 or 500 ppm ZER for 21 weeks. At the termination of the experiments (wk 20 of Exp. 1 and wk 22 of Exp. 2), all animals were subjected to complete necropsy examination to determine the pathological lesions in both tissues. Oral administration of ZER at 100, 250 and 500 ppm significantly inhibited the multiplicity of colonic adenocarcinomas. The treatment also suppressed colonic inflammation. In the lung carcinogenesis, ZER feeding at 250 and 500 ppm significantly inhibited the multiplicity of lung adenomas in a dose-dependent manner. Feeding with ZER resulted in inhibition of proliferation, induction of apoptosis, and suppression of NFkappaB and heme oxygenase (HO)-1 expression in tumors developed in both tissues. Our findings suggest that dietary administration of ZER effectively suppresses mouse colon and lung carcinogenesis through multiple modulatory mechanisms of growth, apoptosis, inflammation and expression of NFkappaB and HO-1 that are involved in carcinogenesis in the colon and lung.

Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases

BACKGROUND

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation.

REVIEW

We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here.

CONCLUSION

Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.

Cancer chemopreventive and therapeutic potential of resveratrol: mechanistic perspectives

A plant kingdom is considered as a gold mine for the discovery of many biologically active substances with therapeutic values. Resveratrol (3,5,4'-trihydroxystilbene), a naturally occurring polyphenol, exhibits pleiotropic health beneficial effects including anti-oxidant, anti-inflammatory, cardioprotective and anti-tumor activities. Currently, numerous preclinical findings suggest resveratrol as a promising nature's arsenal for cancer prevention and treatment. A remarkable progress in dissecting the molecular mechanisms underlying anti-cancer properties of resveratrol has been achieved in the past decade. As a potential anti-cancer agent, resveratrol has been shown to inhibit or retard the growth of various cancer cells in culture and implanted tumors in vivo. The compound significantly inhibits experimental tumorigenesis in a wide range of animal models. Resveratrol targets many components of intracellular signaling pathways including pro-inflammatory mediators, regulators of cell survival and apoptosis, and tumor angiogenic and metastatic switches by modulating a distinct set of upstream kinases, transcription factors and their regulators. This review summarizes the diverse molecular targets of resveratrol with a special focus on those involved in fine-tuning of orchestrated intracellular signal transduction.

Effects of a combination of thyme and oregano essential oils on TNBS-induced colitis in mice

We examined the anti-inflammatory effects of the combination of thyme and oregano essential oil dietary administered at three concentrations (0.4% thyme and 0.2% oregano oils; 0.2% thyme and 0.1% oregano oils; 0.1% thyme and 0.05% oregano oils) on mice with TNBS-induced colitis. Treatment of colitic animals with the essential oils decreased the mRNA levels of pro-inflammatory cytokines IL-1β, IL-6, GM-CSF, and TNFα, especially after application of the medium dose. The medium dose of the essential oils significantly lowered the amount of IL-1β and IL-6 proteins too. Moreover, administration of the medium dose decreased the mortality rate, accelerated the body weight gain recovery, and reduced the macroscopic damage of the colonic tissue. Our results indicate that combined treatment with appropriate concentrations of thyme and oregano essential oils can reduce the production of proinflammatory cytokines, and thereby attenuate TNBS-induced colitis in mice.

Mutagenicity of 8-nitroguanosine, a product of nitrative nucleoside modification by reactive nitrogen oxides, in mammalian cells

8-Nitroguanosine is a nitratively modified nucleoside that is formed endogeneously under inflammatory conditions dependent on nitric oxide production, particularly associated with cancer risks. Here, we investigated the mutagenic potential of 8-nitroguanosine in mammalian cells. Treatment with 8-nitroguanosine (10-1000 microM) for 1h significantly increased (by 6-8 times) the mutation frequency of the xanthine-guanine phosphoribosyltransferase (gpt) gene in AS52 cells without cytotoxic effects. 8-Nitroguanosine treatment induced a G-to-T transversion in gpt gene at position 86. It also significantly increased levels of abasic sites in DNA. These observations suggest that formation of 8-nitroguanosine may contribute to the pathogenesis of inflammation-associated carcinogenesis.

Resveratrol inhibits nitric oxide and prostaglandin E2 production by lipopolysaccharide-activated C6 microglia

Resveratrol, a natural polyphenolic antioxidant found in red wine and grapes, has been reported to exert a variety of important pharmacological effects, including anti-inflammatory, cardioprotective, and cancer chemopreventive properties. In the present study, we investigated the effect of resveratrol on the production of nitric oxide (NO) and prostaglandin (PG) E2 by lipopolysaccharide (LPS)-activated C6 microglia. Exposure of cultured rat C6 astroglioma cells to LPS increased their release of NO and PGE2 and their inducible expression of NO synthase and cyclooxygenase-2, all of which were significantly inhibited by resveratrol pretreatment. Further studies revealed that resveratrol suppressed LPS-induced nuclear translocation and activation of nuclear factor kappaB (NF-kappaB). These results demonstrate a potent suppressive effect of resveratrol on pro-inflammatory responses of microglia by modulation of NF-kappaB activity, suggesting a therapeutic potential for this compound in neurodegenerative diseases accompanied by microglial activation.

Demethylnobiletin inhibits delayed-type hypersensitivity reactions, human lymphocyte proliferation and cytokine production

BACKGROUND AND PURPOSE

Our aim was to examine the effect of demethylnobiletin on various experimental models of delayed-type hypersensitivity (DTH) reactions and to determine its influence on the mediators and enzymes involved in these reactions.

EXPERIMENTAL APPROACH

DTH was induced in mice by oxazolone, dinitrofluorobenzene (DNFB) and sheep red blood cells (SRBC). The effect of demethylnobiletin on the ensuing DTH was studied, especially in relation to oedema formation, cell infiltration and tissue damage. Its activity on different mediators implicated in DTH reactions was also determined and its effect on nitric oxide synthase (NOS)-2 analysed. Finally, its influence on T lymphocyte proliferation, apoptosis and caspase 3 activity was tested.

KEY RESULTS

DTH reactions were all reduced by demethylnobiletin. The experimental results suggest that the compound may act by reducing cell infiltration and by suppressing mediators such as interleukin-2 (IC50=1.63 microM), interleukin-4 (IC50=2.76 microM), tumour necrosis factor-alpha (IC50=0.66 microM), interferon-gamma (IC50=1.35 microM), and interleukin-1 beta (46% at 2.5 microM) and by concomitantly increasing the production of the anti-inflammatory cytokine, interleukin-10. In addition, while demethylnobiletin affected nitric oxide production, it did not modify NOS-2 expression. Finally, demethylnobiletin inhibited proliferation of T cells and induced their apoptosis.

CONCLUSIONS AND IMPLICATIONS

Demethylnobiletin decreased DTH reactions induced by various agents. This finding, along with the fact that the compound has a low toxicity and exhibits several other interesting properties, could pave the way for other structurally related citroflavonoids to be used as pharmacological agents in complementary therapies.

Citrus auraptene suppresses azoxymethane-induced colonic preneoplastic lesions in C57BL/KsJ-db/db mice

The current study was designed to investigate whether dietary citrus auraptene (AUR) suppresses the development of azoxymethane (AOM)-induced colorectal preneoplastic lesions in C57BL/KsJ-db/db (db/db) mice with obese and diabetic phenotypes. Female db/db and wild (+/+) mice were divided into the AOM + AUR, AOM alone, AUR alone, and the untreated groups in each phenotype. AOM was given 3 weekly intraperitoneal injections (10 mg/kg bw). AUR (250 ppm) was given in diet during the study (for 10 wk). Dietary AUR significantly reduced the number of aberrant crypt foci (ACF) and Beta -catenin-accumulated crypt (BCAC) in both phenotypes. The treatment also lowered cell proliferation activity and increased apoptotic cells in both lesions. Our findings indicate that dietary AUR is able to suppress the early phase of colon carcinogenesis in both phenotypes, suggesting possible application of AUR as a chemopreventive agent in both the high-risk and general populations for colorectal cancer.

Nobiletin from citrus fruit peel inhibits the DNA-binding activity of NF-kappaB and ROS production in LPS-activated RAW 264.7 cells

Post-treatment with nobiletin (5,6,7,8,3',4'-hexamethoxy flavone), which was purified from the fruit peel of Citrus sunki Hort. ex Tanaka, at concentration 6-50 microM significantly suppressed NF-kappaB transcriptional activation, NO and PGE(2) production, and iNOS and COX-2 protein expression in lipopolysaccharide (LPS)-activated RAW 264.7 cells. Nobiletin inhibited neither LPS-induced phosphorylation/degradation of inhibitory kappaB-alpha nor LPS-induced nuclear translocation of NF-kappaB. However, it interrupted the DNA-binding activity of activated NF-kappaB. As reactive oxygen species (ROS) are also known to regulate the activation of NF-kappaB, we tested the effect of nobiletin on LPS-induced ROS generation. Nobiletin significantly inhibited LPS-induced intracellular ROS production in RAW 264.7 cells. These results suggest that nobiletin may exert an anti-inflammatory effect through the interruption of NF-kappaB DNA-binding activity and the suppression of ROS generation.

Zerumbone, a bioactive sesquiterpene, induces G2/M cell cycle arrest and apoptosis in leukemia cells via a Fas- and mitochondria-mediated pathway

We demonstrated here for the first time that zerumbone (ZER), a natural cyclic sesquiterpene, significantly suppressed the proliferation of promyelocytic leukemia NB4 cells among several leukemia cell lines, but not human umbilical vein endothelial cells (HUVECs), by inducing G2/M cell cycle arrest followed by apoptosis with 10 microM of IC50. Treatment of NB4 cells with growth-suppressive concentrations of ZER resulted in G2/M cell cycle arrest that was associated with a decline of Cyclin B1 protein, but with the phosphorylation of ATM/ Chk1/Chk2. In addition, ZER induced the phosphorylation of Cdc25C at the Thr48 residue and Cdc2 at the Thr14/Tyr15 residues. Furthermore, ZER-induced apoptosis in NB4 cells was initiated by the expression of Fas (CD95)/Fas Ligand (CD95L), concomitant with the activation of caspase-8. ZER was also found to induce the cleavage of Bid, a mediator that is known to connect the Fas/CD95 cell death receptor to the mitochondrial apoptosis pathway. ZER also induced the cleavage of Bax and Mcl-1 proteins, but not Bcl-2 or Bcl-XL. ZER-induced apoptosis took place in association with a loss of the mitochondrial transmembrane potential as well as the activation of caspase-3 and -9, resulting in the degradation of the proteolytic poly (ADP-ribose) polymerase (PARP). ZER also triggered a release of cytochrome c into the cytoplasm. Both antagonistic anti-Fas antibody ZB4 and pan-caspase inhibitor Z-VAD inhibited ZER-induced apoptosis in NB4 cells. Taken together, ZER is an inducer of apoptosis in leukemic cells that specifically triggers the Fas/CD95- and mitochondria-mediated apoptotic signaling pathway.

Transcriptional regulation via cysteine thiol modification: a novel molecular strategy for chemoprevention and cytoprotection

Chemoprevention refers to the use of defined nontoxic chemical regimens to inhibit, reverse, or retard the process of multistage carcinogenesis that involves multiple signal transduction events. Identification of signaling molecules associated with carcinogenesis as prime targets of chemopreventive agents has become an area of great interest. Recent studies have implicated cysteine thiols present in various transcription factors, such as NF-kappaB, AP-1, and p53 as redox sensors in transcriptional regulation of many genes essential for maintaining cellular homeostasis. Some chemopreventive and cytoprotective agents have been found to target cysteine thiols present in key transcription factors or their regulators, thereby suppressing aberrant over-activation of carcinogenic signal transduction or restoring/normalizing or even potentiating cellular defense signaling. The focus of this review is the oxidation or covalent modification of thiol groups present in key representative redox-sensitive transcription factors and their regulating molecules as a unique strategy for molecular target-based chemoprevention and cytoprotection.

Beneficial effect of resveratrol on cholecystokinin-induced experimental pancreatitis

Resveratrol is a phytoalexin with strong antioxidant and anti-inflammatory effects reaching high concentrations in red wine. The aim of our study was to test the effects of resveratrol pretreatment on cholecystokinin-octapeptide (CCK-8)-induced acute pancreatitis in rats. Animals were divided into a control group, a group treated with CCK-8 and a group receiving 10 mg/kg resveratrol prior to CCK-8 administration. Resveratrol ameliorated the CCK-8-induced changes in the laboratory parameters, and reduced the histological damage in the pancreas. The drug failed to improve the pancreatic antioxidant state, but increased the amount of hepatic reduced glutathione and prevented the reduction of hepatic catalase activity. Resveratrol-induced inhibition of nuclear factor kappa B (NF-kappaB) activation or reduction of the pancreatic tumor necrosis factor-alpha (TNF-alpha) concentration could not be demonstrated. In conclusion, the beneficial effects of resveratrol on acute pancreatitis seem to be mediated by the antioxidant effect of resveratrol or by an NF-kappaB-independent anti-inflammatory mechanism.

Dietary administration with prenyloxycoumarins, auraptene and collinin, inhibits colitis-related colon carcinogenesis in mice

We previously reported the chemopreventive ability of a prenyloxycoumarin auraptene in chemically induced carcinogenesis in digestive tract, liver and urinary bladder of rodents. The current study was designed to determine whether dietary feeding of auraptene and its related prenyloxycoumarin collinin can inhibit colitis-related mouse colon carcinogenesis. The experimental diets, containing the compounds at 2 dose levels (0.01 and 0.05%), were fed for 17 weeks to male CD-1 (ICR) mice that were initiated with a single intraperitoneal injection of azoxymethane (AOM, 10 mg/kg body weight) and promoted by 1% (w/v) DSS in drinking water for 7 days. Their tumor inhibitory effects were assessed at week 20 by counting the incidence and multiplicity of colonic neoplasms and the immunohistochemical expression of proliferating cell nuclear antigen (PCNA)-labeling index, apoptotic index, cyclooxygenase (COX)-2, inducible nitric oxide (iNOS) and nitrotyrosine in colonic epithelial malignancy. Feeding with auraptene or collinin, at both doses, significantly inhibited the occurrence of colonic adenocarcinoma. In addition, feeding with auraptene or collinin significantly lowered the positive rates of PCNA, COX-2, iNOS and nitrotyrosine in adenocarcinomas, while the treatment increased the apoptotic index in colonic malignancies. Our findings may suggest that certain prenyloxycoumarins, such as auraptene and collinin, could serve as an effective agent against colitis-related colon cancer development in rodents.

Effect of isothiocyanates on nuclear accumulation of NF-kappaB, Nrf2, and thioredoxin in caco-2 cells

Early effects (only 1 h of exposure) of three isothiocyanates (benzyl, phenylethyl, and sulforaphane) on nuclear accumulation of thioredoxin, APE/Ref-1, and transcription factors NF-kappaB and Nrf2, as well as production of reactive oxygen species (ROS) and reduced glutathione levels were examined in human adenocarcinoma Caco-2 cells. Nuclear increase of NF-kappaB, Nrf2, and thioredoxin contents was observed in all isothiocyanate-treated cells, whereas the nuclear Ref-1 and cytoplasmic Keap1 contents were not changed. Sulforaphane was the most potent inducer of Nrf2 nuclear accumulation (10 microM, 1.9-fold) and NF-kappaB nuclear accumulation at higher concentration (25 microM, 6.3-fold). In contrast, benzyl isothiocyanate induced more thioredoxin nuclear accumulation (10 microM, 2.9-fold), increased production of ROS, and gave the greatest induction of thioredoxin reductase 1 mRNA (10 microM, 10.2-fold), whereas phenylethyl isothiocyanate was more potent in the depletion of reduced glutathione levels. These results show that different individual isothiocyanates may possess some different activities in nuclear accumulation of thioredoxin, NF-kappaB, Nrf2, and production of ROS.

From traditional Ayurvedic medicine to modern medicine: identification of therapeutic targets for suppression of inflammation and cancer

Cancer is a hyperproliferative disorder that involves transformation, dysregulation of apoptosis, proliferation, invasion, angiogenesis and metastasis. Extensive research during the last 30 years has revealed much about the biology of cancer. Drugs used to treat most cancers are those that can block cell signalling, including growth factor signalling (e.g., epidermal growth factor); prostaglandin production (e.g., COX-2); inflammation (e.g., inflammatory cytokines: NF-kappaB, TNF, IL-1, IL-6, chemokines); drug resistance gene products (e.g., multi-drug resistance); cell cycle proteins (e.g., cyclin D1 and cyclin E); angiogenesis (e.g., vascular endothelial growth factor); invasion (e.g., matrix metalloproteinases); antiapoptosis (e.g., bcl-2, bcl-X(L), XIAP, survivin, FLIP); and cellular proliferation (e.g., c-myc, AP-1, growth factors). Numerous reports have suggested that Ayurvedic plants and their components mediate their effects by modulating several of these recently identified therapeutic targets. However, Ayurvedic medicine requires rediscovery in light of our current knowledge of allopathic (modern) medicine. The focus of this review is to elucidate the Ayurvedic concept of cancer, including its classification, causes, pathogenesis and prevention; surgical removal of tumours; herbal remedies; dietary modifications; and spiritual treatments.

Zerumbone abolishes NF-kappaB and IkappaBalpha kinase activation leading to suppression of antiapoptotic and metastatic gene expression, upregulation of apoptosis, and downregulation of invasion

Zerumbone found in subtropical ginger Zingiber zerumbet Smith exhibits antiproliferative and antiinflammatory activities but underlying molecular mechanisms are poorly understood. As several genes that regulate proliferation and apoptosis are regulated by nuclear factor (NF)-kappaB, we hypothesized that zerumbone mediates its activity through the modulation of NF-kappaB activation. We found that zerumbone suppressed NF-kappaB activation induced by tumor necrosis factor (TNF), okadaic acid, cigarette smoke condensate, phorbol myristate acetate, and H2O2 and that the suppression was not cell type specific. Interestingly, alpha-humulene, a structural analogue of zerumbone lacking the carbonyl group, was completely inactive. Besides being inducible, constitutively active NF-kappaB was also inhibited. NF-kappaB inhibition by zerumbone correlated with sequential suppression of the IkappaBalpha kinase activity, IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation, p65 nuclear translocation, and p65 acylation. Zerumbone also inhibited the NF-kappaB-dependent reporter gene expression activated by TNF, TNFR1, TRADD, TRAF2, NIK, and IKK but not that activated by the p65 subunit of NF-kappaB. NF-kappaB-regulated gene products, such as cyclin D1, COX-2, MMP-9, ICAM-1, c-Myc, survivin, IAP1, IAP2, XIAP, Bcl-2, Bcl-xL, Bfl-1/A1, TRAF1 and FLIP, were all downregulated by zerumbone. This downregulation led to the potentiation of apoptosis induced by cytokines and chemotherapeutic agents. Zerumbone's inhibition of expression of these NF-kappaB-regulated genes also correlated with the suppression of TNF-induced invasion activity. Overall, our results indicated that zerumbone inhibits the activation of NF-kappaB and NF-kappaB-regulated gene expression induced by carcinogens and that this inhibition may provide a molecular basis for the prevention and treatment of cancer by zerumbone.

Redox-sensitive transcription factors as prime targets for chemoprevention with anti-inflammatory and antioxidative phytochemicals

Oxidative stress has been implicated in various pathological conditions including cancer. However, the human body has an intrinsic ability to fight against oxidative stress. A wide array of phase 2 detoxifying or antioxidant enzymes constitutes a fundamental cellular defense system against oxidative and electrophilic insults. Transcriptional activation of genes encoding detoxifying and antioxidant enzymes by NF-E2 related factor 2 (Nrf2), a member of the cap'n'collar family of basic leucine zipper transcription factors, may protect cells and tissues from oxidative damage. Many chemopreventive and chemoprotective phytochemicals have been found to enhance cellular antioxidant capacity through activation of this particular transcription factor, thereby blocking initiation of carcinogenesis. A new horizon in chemoprevention research is the recent discovery of molecular links between inflammation and cancer. Components of the cell signaling pathways, especially those that converge on redox-sensitive transcription factors, including nuclear factor-kappaB (NF-kappaB) and activator protein 1 (AP-1) involved in mediating inflammatory response, have been implicated in carcinogenesis. A wide variety of chemopreventive and chemoprotective agents can alter or correct undesired cellular functions caused by abnormal proinflammatory signal transmission mediated by inappropriately activated NF-kappaB and AP-1. The modulation of cellular signaling by anti-inflammatory phytochemicals hence provides a rational and pragmatic strategy for molecular target-based chemoprevention.

Beta-phenylethyl and 8-methylsulphinyloctyl isothiocyanates, constituents of watercress, suppress LPS induced production of nitric oxide and prostaglandin E2 in RAW 264.7 macrophages

Beta-phenylethyl (PEITC) and 8-methylsulphinyloctyl isothiocyanates (MSO) represent two phytochemical constituents present in watercress Rorripa nasturtium aquaticum, with known chemopreventative properties. In the present investigation, we examined whether PEITC and MSO could modulate the inflammatory response of Raw 264.7 macrophages to bacterial lipopolysaccharide (LPS) by assessment of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. Overproduction of both nitric oxide (NO) and prostaglandins (PGE) has been associated with numerous pathological conditions including chronic inflammation and cancer. Our results demonstrate that LPS (1 microg/ml approximately 24 h) induced nitrite and prostaglandin E2 (PGE-2) synthesis in Raw 264.7 cells was attenuated by both isothiocyanates (ITCs) in a concentration-dependent manner. Both PEITC and MSO decreased (iNOS) and (COX-2) protein expression levels leading to reduced secretion of both pro-inflammatory mediators. Interestingly, the reduction in both iNOS and COX-2 expression were associated with the inactivation of nuclear factor-kappaB and stabilization of IkappaBalpha. Taken together our data gives further insight into the possible chemopreventative properties of two dietary derived isothiocyanates from watercress.

Specific inhibition of MyD88-independent signaling pathways of TLR3 and TLR4 by resveratrol: molecular targets are TBK1 and RIP1 in TRIF complex

TLRs can activate two distinct branches of downstream signaling pathways. MyD88 and Toll/IL-1R domain-containing adaptor inducing IFN-beta (TRIF) pathways lead to the expression of proinflammatory cytokines and type I IFN genes, respectively. Numerous reports have demonstrated that resveratrol, a phytoalexin with anti-inflammatory effects, inhibits NF-kappaB activation and other downstream signaling pathways leading to the suppression of target gene expression. However, the direct targets of resveratrol have not been identified. In this study, we attempted to identify the molecular target for resveratrol in TLR-mediated signaling pathways. Resveratrol suppressed NF-kappaB activation and cyclooxygenase-2 expression in RAW264.7 cells following TLR3 and TLR4 stimulation, but not TLR2 or TLR9. Further, resveratrol inhibited NF-kappaB activation induced by TRIF, but not by MyD88. The activation of IFN regulatory factor 3 and the expression of IFN-beta induced by LPS, poly(I:C), or TRIF were also suppressed by resveratrol. The suppressive effect of resveratrol on LPS-induced NF-kappaB activation was abolished in TRIF-deficient mouse embryonic fibroblasts, whereas LPS-induced degradation of IkappaBalpha and expression of cyclooxygenase-2 and inducible NO synthase were still inhibited in MyD88-deficient macrophages. Furthermore, resveratrol inhibited the kinase activity of TANK-binding kinase 1 and the NF-kappaB activation induced by RIP1 in RAW264.7 cells. Together, these results demonstrate that resveratrol specifically inhibits TRIF signaling in the TLR3 and TLR4 pathway by targeting TANK-binding kinase 1 and RIP1 in TRIF complex. The results raise the possibility that certain dietary phytochemicals can modulate TLR-derived signaling and inflammatory target gene expression and can alter susceptibility to microbial infection and chronic inflammatory diseases.

Differential effects of organosulfur compounds from garlic oil on nitric oxide and prostaglandin E2 in stimulated macrophages

OBJECTIVE

We investigated the inhibition of nitric oxide (NO) and prostaglandin E2 (PGE2) production by the garlic oil derivatives, diallyl sulfide (DAS), diallyl disulfide (DADS), and allyl methyl sulfide (AMS), in lipopolysaccharide (LPS)-activated RAW 264.7 cells.

METHODS

Cells were treated with LPS (330 ng/mL) and various concentrations of DAS, DADS, and AMS. NO and PGE2 released into the medium and expressions of inducible NO synthase and cyclooxygenase-2 protein were measured.

RESULTS

All three compounds suppressed stimulated NO production, among which AMS exhibited the least inhibition. Western blot analysis showed that DAS and DADS, but not AMS, inhibited the corresponding inducible NO synthase expression. An in vitro study showed that all three compounds possess NO clearance activity, and that DADS and AMS were more effective than DAS. On the contrary, only DAS inhibited activated PGE2 production and cyclooxygenase-2 protein expression.

CONCLUSIONS

The garlic derivatives, DAS, DADS, and AMS, differentially regulated the production of NO and PGE2 in stimulated macrophages. DAS decreased stimulated NO and PGE2 production by inhibiting inducible NO synthase and cyclooxygenase-2 expressions, and its enzyme inhibiting and NO clearance activity may also partly contribute to the suppression of NO. DADS inhibited activated NO production by decreasing inducible NO synthase expression and by directly clearing NO, whereas AMS suppressed NO mainly through its direct NO clearance activity. Further, neither DADS nor AMS showed any inhibitory effect on stimulated PGE2 production.

1'S-1'-Acetoxychavicol acetate as a new type inhibitor of interferon-beta production in lipopolysaccharide-activated mouse peritoneal macrophages

1'S-1'-Acetoxychavicol acetate from the rhizomes of Alpinia galanga was known to show potent inhibitory effect on the production of nitric oxide (NO) in lipopolysaccharide-activated mouse peritoneal macrophages. To clarify its mechanism of action, the effects of 1'S-1'-acetoxychavicol acetate on the expression of interferon-beta (IFN-beta) mRNA and activation of nuclear factor-kappaB (NF-kappaB), both of which participate in the induction of inducible NO synthase, were examined in lipopolysaccharide-activated macrophages. The results were compared with those of two inhibitors of the NF-kappaB activation, costunolide and caffeic acid phenethyl ester. 1'S-1'-Acetoxychavicol acetate inhibited IFN-beta mRNA expression as well as NF-kappaB activation, and two related compounds, (+/-)-1-acetoxy-1-(2-acetoxyphenyl)-2-propene and (+/-)-1-acetoxy-1-(4-acetoxyphenol)-3-butene, also inhibited IFN-beta mRNA expression. In addition, 1'S-1'-acetoxychavicol acetate inhibited the production of NO stimulated by poly(I:C) via Toll-like receptor 3.

Resveratrol inhibits nitric oxide and TNF-alpha production by lipopolysaccharide-activated microglia

Upon activation, brain macrophages, the microglia, release proinflammatory mediators that play important roles in eliciting neuroinflammatory responses associated with neurodegenerative diseases. As resveratrol, an antioxidant component of grape, has been reported to exert anti-inflammatory activities on macrophages, we investigated its effects on the production of TNF-alpha (TNF-alpha) and nitric oxide (NO) by lipopolysaccharide (LPS)-activated microglia. Exposure of cultured rat cortical microglia and a mouse microglial cell line N9 to LPS increased their release of TNF-alpha and NO, which was significantly inhibited by resveratrol. Further studies revealed that resveratrol suppressed LPS-induced degradation of IkappaBalpha, expression of iNOS and phosphorylation of p38 mitogen-activated protein kinases (MAPKs) in N9 microglial cells. These results demonstrate a potent suppressive effect of resveratrol on proinflammatory responses of microglia, suggesting a therapeutic potential for this compound in neurodegenerative diseases accompanied by microglial activation.

Identification of a novel blocker of I kappa B alpha kinase that enhances cellular apoptosis and inhibits cellular invasion through suppression of NF-kappa B-regulated gene products

1'-Acetoxychavicol acetate (ACA), extracted from rhizomes of the commonly used ethno-medicinal plant Languas galanga, has been found to suppress chemical- and virus-induced tumor initiation and promotion through a poorly understood mechanism. Because several genes that regulate cellular proliferation, carcinogenesis, metastasis, and survival are regulated by activation of the transcription factor NF-kappaB, we postulated that ACA might mediate its activity through modulation of NF-kappaB activation. For this report, we investigated the effect of ACA on NF-kappaB and NF-kappaB-regulated gene expression activated by various carcinogens. We found that ACA suppressed NF-kappaB activation induced by a wide variety of inflammatory and carcinogenic agents, including TNF, IL-1beta, PMA, LPS, H(2)O(2), doxorubicin, and cigarette smoke condensate. Suppression was not cell type specific, because both inducible and constitutive NF-kappaB activations were blocked by ACA. ACA did not interfere with the binding of NF-kappaB to the DNA, but, rather, inhibited IkappaBalpha kinase activation, IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation, and subsequent p65 nuclear translocation. ACA also inhibited NF-kappaB-dependent reporter gene expression activated by TNF, TNFR1, TNFR-associated death domain protein, TNFR-associated factor-2, and IkappaBalpha kinase, but not that activated by p65. Consequently, ACA suppressed the expression of TNF-induced NF-kappaB-regulated proliferative (e.g., cyclin D1 and c-Myc), antiapoptotic (survivin, inhibitor of apoptosis protein-1 (IAP1), IAP2, X-chromosome-linked IAP, Bcl-2, Bcl-x(L), Bfl-1/A1, and FLIP), and metastatic (cyclooxygenase-2, ICAM-1, vascular endothelial growth factor, and matrix metalloprotease-9) gene products. ACA also enhanced the apoptosis induced by TNF and chemotherapeutic agents and suppressed invasion. Overall, our results indicate that ACA inhibits activation of NF-kappaB and NF-kappaB-regulated gene expression, which may explain the ability of ACA to enhance apoptosis and inhibit invasion.

Effect of cis-resveratrol on genes involved in nuclear factor kappa B signaling

This study investigated for the first time the effects of the cis isomer of RESV (c-RESV), a polyphenol present in red wine, on an array of genes whose expression is controlled by nuclear factor kappa B (NF-kappaB) and whose transcriptional activation is critical in a number of pathologies (including some cardiovascular diseases). In inflammatory peritoneal macrophages stimulated with lipopolysaccharide (LPS) and gamma interferon (IFN-gamma), c-RESV significantly blocked the expression of genes related to the REL/NF-kappaB/IkappaB family, adhesion molecules and acute-phase proteins; however, the greatest modulatory effect was obtained on the expression of genes related to the pro-inflammatory cytokines. c-RESV down-regulated the nuclear factor of kappa light chain gene enhancer in B-cells 1 (NFkappaBL1) gene product p105 and up-regulated the nuclear factor of kappa light chain gene enhancer in B-cells inhibitor alpha (IkappaBalpha) gene. c-RESV also significantly inhibited intercellular adhesion molecule-1 (ICAM-1) gene expression and the transmembrane receptors RIP (receptor TNFRSF) and TLR3 (toll-like receptor 7). At 100 muM, c-RESV significantly inhibited transcription of Scya2 (chemokine MCP-1), the chemokine RANTES (regulated on activation, normal T cell expressed and secreted), pro-inflammatory cytokines that attract monocyte-granulocyte cells such as M-CSF (colony-stimulating factor 1), GM-CSF (colony-stimulating factor 2) and G-CSF (colony-stimulating factor 3), the cytokine tumor growth factor beta (TGF-beta) and the extracellular ligand IL-1alpha. In contrast, c-RESV stimulated transcription of the pro-inflammatory cytokines IL-6 and tumor necrosis factor alpha (TNF-alpha), the extracellular ligand IL-1beta, and the IFN regulatory factor (IRF)-1. In conclusion, c-RESV has a significant modulatory effect on the NF-kappaB signaling pathway and, consequently, an important antioxidant role that may partially explain the cardioprotective effects attributed to long-term moderate red wine consumption.

Effects of dietary phytoestrogens on cardiac remodeling secondary to chronic volume overload in female rats

Previously, we demonstrated that intact female rats fed a standard rodent diet containing soybean products exhibit essentially no adverse left ventricular (LV) remodeling in response to aortocaval fistula-induced chronic volume overload. We hypothesized that phytoestrogenic compounds in the diet contributed to the female cardioprotection. To test this hypothesis, four groups of female rats were studied: sham-operated (Sham) and fistula (Fist) rats fed a diet with [P(+)] or without [P(-)] phytoestrogens. Eight weeks postfistula, systolic and diastolic cardiac function was assessed by using a blood-perfused, isolated heart preparation. High-phytoestrogen diet had no effect on body, heart, and lung weights, or cardiac function in Sham rats. Fistula groups developed LV hypertrophy, which was not reduced by dietary phytoestrogens [1,184 +/- 229 mg Fist-P(-) and 1,079 +/- 199 mg Fist-P(+) vs. 620 +/- 47 mg for combined Sham groups, P < 0.05]. Unstressed LV volume increased in Fist-P(-) rats (428 +/- 16 vs. 300 +/- 14 microl Sham, P < 0.0001), but it was not different from Sham for Fist-P(+) animals (286 +/- 17 microl). Fist-P(-) rats developed increased ventricular compliance (5.3 +/- 0.8 vs. 2.3 +/- 0.3 microl/mmHg Sham, P < 0.01), whereas Fist-P(+) rats had no change in compliance (2.8 +/- 0.4 mul/mmHg). Intrinsic ventricular contractility was maintained in the Fist-P(+) rats, but it was reduced (P < 0.001) in the Fist-P(-) rats [systolic pressure-volume slope: 1.04 +/- 0.03, 0.60 +/- 0.06, and 0.99 +/- 0.08 mmHg/microl, for Fist-P(+), Fist-P(-), and Sham, respectively]. These data indicate that dietary phytoestrogens contribute significantly to female cardioprotection against volume overload-induced adverse ventricular remodeling and that studies evaluating gender differences in cardiovascular remodeling must consider the influence of dietary phytoestrogens.

Broccoli and watercress suppress matrix metalloproteinase-9 activity and invasiveness of human MDA-MB-231 breast cancer cells

A high dietary intake of cruciferous vegetables has been associated with a reduction in numerous human pathologies particularly cancer. In the current study, we examined the inhibitory effects of broccoli (Brassica oleracea var. italica) and watercress (Rorripa nasturtium aquaticum) extracts on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cancer cell invasion and matrix metalloproteinase-9 activity using human MDA-MB-231 breast cancer cells. Aberrant overexpression of matrix metalloproteinases, including metalloproteinase-9, is associated with increased invasive potential in cancer cell lines. Our results demonstrate that extracts of broccoli and Rorripa suppressed TPA-induced MMP-9 activity and invasiveness in a concentration dependent manner as determined by zymographic analysis. Furthermore, fractionation of individual extracts followed by liquid chromatography mass spectroscopy analysis (LC-MS) revealed that the inhibitory effects of each vegetable were associated with the presence of 4-methysulfinylbutyl (sulforaphane) and 7-methylsulphinylheptyl isothiocyanates. Taken together, our data indicate that isothiocyanates derived form broccoli and Rorripa inhibit metalloproteinase 9 activities and also suppress the invasive potential of human MDA-MB-231 breast cancer cells in vitro. The inhibitory effects observed in the current study may contribute to the suppression of carcinogenesis by diets high in cruciferous vegetables.

Signal transduction network leading to COX-2 Induction: a road map in search of cancer chemopreventives

Cancer is still a major global health concern even after an everlasting strive in conquering this dread disease. Emphasis is now given to chemoprevention to reduce the risk of cancer and also to improve the quality of life among cancer afflicted individuals. Recent progress in molecular biology of cancer has identified key components of the cellular signaling network, whose functional abnormality results in undesired alterations in cellular homeostasis, creating a cellular microenvironment that favors premalignant and malignant transformation. Multiple lines of evidence suggest an elevated expression of cyclooxygenase-2 (COX-2) is causally linked to cancer. In response to oxidative/pro-inflammatory stimuli, turning on unusual signaling arrays mediated through diverse classes of kinases and transcription factors results in aberrant expression of COX-2. Population-based as well as laboratory studies have explored a broad spectrum of chemopreventive agents including selective COX-2 inhibitors and a wide variety of anti-inflammatory phytochemicals, which have been shown to target cellular signaling molecules as underlying mechanisms of chemoprevention. Thus, unraveling signaling pathways regulating aberrant COX-2 expression and targeted blocking of one or more components of those signal cascades may be exploited in searching chemopreventive agents in the future.

Molecular basis of chemoprevention by resveratrol: NF-kappaB and AP-1 as potential targets

Recently, chemoprevention by the use of naturally occurring substances is considered as a priority to reduce the ever-increasing incidence of cancer. The intervention of multistage carcinogenesis by modulating intracellular signaling pathways may provide molecular basis of chemoprevention with a wide variety of dietary phytochemicals. Resveratrol, a red wine polyphenol, has been studied extensively for the chemopreventive activity in the context of its ability to interfere with the multistage carcinogenesis. Numerous intracellular signaling cascades converge with the activation of nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1), which act independently or coordinately to regulate expression of target genes. These ubiquitous eukaryotic transcription factors mediate pleiotropic effects on cellular transformation and tumor promotion. This review aims to update the molecular mechanisms underlying chemoprevention by resveratrol with special focus on its effect on cellular signaling cascades mediated by NF-kappaB and AP-1.

Dietary isoflavones suppress endotoxin-induced inflammatory reaction in liver and intestine

Dietary isoflavone intake has been linked to cancer prevention and their anti-inflammation activity was examined. Intraperitoneal lipopolysaccharide (LPS) injection in mice led to a decrease in the liver antioxidant glutathione level but this decrease was prevented in mice fed with an isoflavone-containing diet. Similarly, isoflavone diet prevented the inflammation-associated induction of metallothionein (MT) in the intestine; and the induction of manganese superoxide dismutase (Mn-SOD) in the liver. Results from the intestinal cell studies suggest that isoflavones suppress the intestinal response to inflammation by modulating the action of pro-inflammatory cytokine, IL-6. IL-6 secretion and the STAT3 (signal transducer and activator of transcription protein 3) nuclear translocation in response to IL-6 were both decreased by genistein.

Quercetin induces apoptosis of Trypanosoma brucei gambiense and decreases the proinflammatory response of human macrophages

In addition to parasite spread, the severity of disease observed in cases of human African trypanosomiasis (HAT), or sleeping sickness, is associated with increased levels of inflammatory mediators, including tumor necrosis factor (TNF)-alpha and nitric oxide derivatives. In the present study, quercetin (3,3',4',5,7-pentahydroxyflavone), a potent immunomodulating flavonoid, was shown to directly induce the death of Trypanosoma brucei gambiense, the causative agent of HAT, without affecting normal human cell viability. Quercetin directly promoted T. b. gambiense death by apoptosis as shown by Annexin V binding. In addition to microbicidal activity, quercetin induced dose-dependent decreases in the levels of TNF-alpha and nitric oxide produced by activated human macrophages. These results highlight the potential use of quercetin as an antimicrobial and anti-inflammatory agent for the treatment of African trypanomiasis.

Effects of cis-resveratrol on inflammatory murine macrophages: antioxidant activity and down-regulation of inflammatory genes

This study investigated for the first time the effects of the cis isomer of resveratrol (c-RESV) on the responses of inflammatory murine peritoneal macrophages, namely on the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) during the respiratory burst; on the biosynthesis of other mediators of inflammation such prostaglandins; and on the expression of inflammatory genes such as inducible nitric oxide synthase (NOS)-2 and inducible cyclooxygenase (COX)-2. Treatment with 1-100 microM c-RESV significantly inhibited intracellular and extracellular ROS production, and c-RESV at 10-100 microM significantly reduced RNS production. c-RESV at 1-100 microM was ineffective for scavenging superoxide radicals (O(2)(.-)), generated enzymatically by a hypoxanthine (HX)/xanthine oxidase (XO) system and/or for inhibiting XO activity. However, c-RESV at 10-100 microM decreased nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate (NADH/NADPH) oxidase activity in macrophage homogenates. c-RESV at 100 microM decreased NOS-2 and COX-2 mRNA levels in lipopolysaccharide (LPS) interferon gamma (IFN-gamma)-treated macrophages. At 10-100 microM, c-RESV also significantly inhibited NOS-2 and COX-2 protein synthesis and decreased prostaglandin E(2) (PGE(2)) production. These results indicate that c-RESV at micromolar concentrations significantly attenuates several components of the macrophage response to proinflammatory stimuli (notably, production of O(2)(.-)(-) and of the proinflammatory mediators NO(.-) and PGE(2)).

[A rare cause of neonatal exudative enteropathy: congenital Langerhans cell histiocytosis (histiocytosis X)]

A case of Langerhans cell histiocytosis is reported in a neonate. Intestinal involvement was especially diffuse and severe, presenting as a protein-losing enteropathy secondary to massive mucosal infiltration by histiocytic cells. The infant died at the age of 3 1/2 months despite therapy with corticosteroids and vinblastine then etoposide and interferon. Such an outcome confirmed the severity of forms with neonatal onset and digestive involvement.