2'-hydroxychalcone inhibits nuclear factor-kappaB and blocks tumor necrosis factor-alpha- and lipopolysaccharide-induced adhesion of neutrophils to human umbilical vein endothelial cells

The modulating effect of methoxy-derivatives of 2'-hydroxychalcones on the release of IL-8, MIF, VCAM-1 and ICAM-1 by colon cancer cells

Colon cancer is one of the leading causes of death in the world. The search for effective and minimally invasive methods of treating colon cancer is the aim of modern medicine. Chalcones and their derivatives have shown an anticancer activity. The aim of the study was to evaluate the effect of methoxy-derivatives of 2'-hydroxychalcones: 2'-hydroxy-3"-methoxychalcone (TJ3), 2'-hydroxy-2"-methoxychalcone (TJ6) and 2'-hydroxy-4"-metoxychalcone (TJ7) at the concentrations of 10 µM and 25 µM on the release of IL-8, MIF, VCAM-1, ICAM-1 by colon cancer SW480 and SW620 cell lines. The cytokines and adhesion molecules were detected using the Bio-Plex Magnetic Luminex Assay and the Bio-Plex Suspension Array System. Our results showed that all tested methoxy-derivatives of 2'-hydroxychalcone compounds significantly reduced ICAM-1 released by SW480 cancer cells. The tested compounds at both concentrations did not significantly affect VCAM-1 released by SW480 and SW620 cancer cell lines. All methoxy-derivatives significantly reduced the concentration of MIF in dose dependent manner on SW480 cells. The TJ3 at the concentration of 25 µM significantly decreased IL-8 secreted by SW480 and SW620 cancer cells. Our results demonstrated that tested methoxy-derivatives of 2'-hydroxychalcones showed modulating effect on colon cancer cells.

Emerging theranostic gold nanostructures to combat cancer: Novel probes for Combinatorial Immunotherapy and Photothermal Therapy

The application of gold nanoparticles in immunotherapy has emerged as one of the most effective therapeutic strategy for eradicating cancer by releasing antigens, oligonucleotides, adjuvants, immune-stimulating agents into the body. Gold nanoparticles are found to be a superior choice, for generating attack on oncogenic cells, due to their low toxicity, better target specificity, diagnostic capabilities, and enhanced cellular uptake rate. This review focuses on the efficiency of several functionalized gold nanoparticles of diverse shapes and sizes as delivery vehicles to desired target cells through effective immunotherapy, along with a brief discussion about photothermal therapy.

Synthesis and anti-inflammatory activity evaluation of novel chroman derivatives

In an effort to develop potent anti-inflammatory agents, a series of novel chroman derivatives including acyclic amidochromans, chromanyl esters and chromanyl acrylates have been designed, synthesized and fully characterized.

Functionalized gold nanostructures: promising gene delivery vehicles in cancer treatment

Surface-modified gold nanoparticles are recognized as promising gene delivery vehicles in the treatment of cancer owing to their excellent biocompatibility with biomolecules (like DNA or RNA) and their unique optical and structural properties. In this context, this review article focuses on the diverse transfection abilities of the gene to the targeted cell on the basis of different shapes and sizes of gold nanoparticles in order to promote its effective expression for cancer treatment. In addition, recent trends in gold nanoparticle mediated gene silencing, gene delivery, detection and combinatory therapies are highlighted considering their cytotoxic effects on healthy human cells.

Various functions of gold nanoparticles in conjugation with nucleic acids.

From Carbamate to Chalcone: Consecutive Anionic Fries Rearrangement, Anionic Si → C Alkyl Rearrangement, and Claisen-Schmidt Condensation

A highly efficient one-pot procedure was developed for the synthesis of various 2'-hydroxychalcones from phenyl diethylcarbamate, featuring consecutive Snieckus-Fries rearrangement, anionic Si → C alkyl rearrangement, and Claisen-Schmidt condensation in a single operation. The applicability of this protocol was demonstrated by the highly efficient synthesis of the anti-inflammatory natural product lonchocarpin. The mechanism insight is also provided.

2,3-Dimethoxy-2'-hydroxychalcone ameliorates TNF-α-induced ICAM-1 expression and subsequent monocyte adhesiveness via NF-kappaB inhibition and HO-1 induction in HaCaT cells

Up-regulation of adhesion molecules plays an important role in the infiltration of leukocytes into the skin during the development of various inflammatory skin diseases, such as atopic dermatitis. In this study, we investigated the modulatory effects of 2,3-dimethoxy-2′-hydroxychalcone (DMHC) on tumor necrosis factor (TNF)-α-induced intercellular adhesion molecule-1 (ICAM-1) expression and monocyte adhesiveness, as well as the molecular mechanisms underlying its action in the HaCaT human keratinocyte cell line. Pre-treating HaCaT cells with DMHC significantly suppressed TNF-α-induced ICAM-1 expression and subsequent monocyte adhesiveness. DMHC inhibited TNF-α-induced activation of NF-ᴋB. In addition, DMHC induced HO-1 expression as well as NRF2 activation. Furthermore, HO-1 knockdown using siRNA reversed the inhibitory effect of DMHC on TNF-α-induced ICAM-1 expression and adhesion of monocytes to keratinocytes. These results suggest that DMHC may inhibit TNF-α-induced ICAM-1 expression and adhesion of monocytes to keratinocytes by suppressing the signaling cascades leading to NF-ᴋB activation and inducing HO-1 expression in keratinocytes. [BMB Reports 2016; 49(1): 57-62]

(E)-1-(Anthracen-9-yl)-3-(2-chloro-6-fluoro-phen-yl)prop-2-en-1-one: crystal structure and Hirshfeld surface analysis

In the title compound, C23H14ClFO, the enone moiety adopts an E conformation. The dihedral angle between the benzene and anthracene ring is 63.42 (8)° and an intra-molecular C-H⋯F hydrogen bond generates an S(6) ring motif. In the crystal, mol-ecules are arranged into centrosymmetric dimers via pairs of C-H⋯F hydrogen bonds. The crystal structure also features C-H⋯π and π-π inter-actions. Hirshfeld surface analysis was used to confirm the existence of inter-molecular inter-actions.

Enhancement of ICAM-1 via the JAK2/STAT3 signaling pathway in a rat model of severe acute pancreatitis-associated lung injury

Acute lung injury (ALI), which is associated with severe acute pancreatitis (SAP), results from damage to the pulmonary microvascular endothelial cells (PMVECs), which in turn leads to high levels of inflammatory cytokines that destroy PMVECs. However, the molecular mechanisms underlying SAP-associated ALI (SAP-ALI) are currently not well understood. Intercellular adhesion molecule-1 (ICAM-1) has been implicated in the persistent migration and accumulation of neutrophils and macrophages, which in turn has been associated with the increased permeability of microvascular endothelial cells. Signal transduction via the Janus kinase-2 (JAK2)/signal transducer and activator of transcription-3 (STAT3) transcription factors has been shown to be involved in inflammation. The present study aimed to investigate the expression levels of ICAM-1 and JAK2/STAT3 signaling components in a rat model of SAP-ALI. SAP was induced in the rat model, and dexamethasone (DEX) was administered to the treatment group. Subsequently, ICAM-1, interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, JAK2, STAT3 and nuclear factor (NF)-κB mRNA expression levels were determined using reverse transcription-polymerase chain reaction; ICAM-1 protein expression levels were determined using western blotting; and IL-6, IL-8 and TNF-α levels were measured via an enzyme-linked immunosorbent assay. In addition, an immunohistochemical analysis of ICAM-1, NF-κB, JAK2 and STAT3 was conducted, and the protein expression and cell morphology of the lungs in all rats was analyzed. ICAM-1 mRNA and protein expression levels were significantly increased following induction of SAP, and were significantly decreased in the DEX-treated group. Furthermore, treatment with DEX significantly reduced serum expression levels of IL-6, IL-8 and TNF-α and decreased expression levels of NF-κB, JAK2 and STAT3 in the lung tissue, as compared with the untreated SAP group. The present study demonstrated that DEX treatment was able to suppress ICAM-1 mRNA and protein expression in a rat model of SAP-ALI via the inhibition of IL-6 and TNF-α-induced JAK2/STAT3 activation; thus suggesting that DEX treatment may be considered a potential strategy in the treatment of patients with SAP-ALI.

Molecular targeted approaches to cancer therapy and prevention using chalcones

There is an emerging paradigm shift in oncology that seeks to emphasize molecularly targeted approaches for cancer prevention and therapy. Chalcones (1,3-diphenyl-2-propen-1-ones), naturally-occurring compounds with widespread distribution in spices, tea, beer, fruits and vegetables, consist of open-chain flavonoids in which the two aromatic rings are joined by a three-carbon α, β-unsaturated carbonyl system. Due to their structural diversity, relative ease of chemical manipulation and reaction of α, β-unsaturated carbonyl moiety with cysteine residues in proteins, some lead chalcones from both natural products and synthesis have been identified in a variety of screening assays for modulating important pathways or molecular targets in cancers. These pathways and targets that are affected by chalcones include MDM2/p53, tubulin, proteasome, NF-kappa B, TRIAL/death receptors and mitochondria mediated apoptotic pathways, cell cycle, STAT3, AP-1, NRF2, AR, ER, PPAR-γ and β-catenin/Wnt. Compared to current cancer targeted therapeutic drugs, chalcones have the advantages of being inexpensive, easily available and less toxic; the ease of synthesis of chalcones from substituted benzaldehydes and acetophenones also makes them an attractive drug scaffold. Therefore, this review is focused on molecular targets of chalcones and their potential implications in cancer prevention and therapy.

Butein suppresses ICAM-1 expression through the inhibition of IκBα and c-Jun phosphorylation in TNF-α- and PMA-treated HUVECs

Butein (3,4,2',4'-tetrahydroxychalcone), a flavonoid derivative, has been reported to show several biological actions, including anti-inflammatory and anti-cancer. However, the possible molecular mechanisms involved are poorly understood. Treatment of human umbilical vein endothelial cells (HUVECs) with butein significantly inhibited cell surface intercellular adhesion molecule-1 (ICAM-1) expression, ICAM-1 protein synthesis, and mRNA expression induced by tumor necrotic factor-α (TNF-α) and/or phorbol 12-myristate 13-acetate (PMA). Electrophoretic mobility shift assay revealed that butein blocked activation of transcription factors, nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), induced by TNF-α and PMA. Moreover, butein abolished TNF-α- and PMA-induced IκBα phosphorylation, which participates in NF-κB activation, and PMA-induced phosphorylation of c-Jun, a subunit composed of AP-1. In vitro, butein inhibited the phosphorylation of c-Jun, binding to GST beads, mediated by JNK isolated from PMA-treated cells. The inhibitory action of butein on the JNK-mediated in vitro c-Jun phosphorylation was abrogated in the presence of ATP. These results indicate that in HUVECs, butein suppresses the expression of ICAM-1 mRNA and protein through the inhibition of the activation of NF-κB and AP-1 induced by TNF-α and PMA, that the inhibitory action of butein on NF-κB activation results from the inhibition of IκBα phosphorylation by IκB kinase (IKK), and that the inactivation of PMA-activated AP-1 by butein is due to the blocking of JNK-mediated c-Jun phosphorylation through the inhibition of ATP binding.

TI-I-174, a Synthetic Chalcone Derivative, Suppresses Nitric Oxide Production in Murine Macrophages via Heme Oxygenase-1 Induction and Inhibition of AP-1

Chalcones (1,3-diaryl-2-propen-1-ones), a flavonoid subfamily, are widely known for their anti-inflammatory properties. Propenone moiety in chalcones is known to play an important role in generating biological responses by chalcones. In the present study, we synthesized chalcone derivatives structurally modified in propenone moiety and examined inhibitory effect on nitric oxide (NO) production and its potential mechanisms. Among the chalcone derivatives used for this study, TI-I-174 (3-(2-Hydroxyphenyl)-1-(thiophen-3-yl)prop-2-en-1-one) most potently inhibited lipopolysaccharide (LPS)-stimulated nitrite production in RAW 264.7 macrophages. TI-I-174 treatment also markedly inhibited inducible nitric oxide synthase (iNOS) expression. However, TI-I-174 did not significantly affect production of IL-6, cyclooxygenase-2 (COX-2) and tumor necrosis factor-α (TNF-α), implying that TI-I-174 inhibits production of inflammatory mediators in a selective manner. Treatment of macrophages with TI-I-174 significantly inhibited transcriptional activity of activator protein-1 (AP-1) as determined by luciferase reporter gene assay, whereas nuclear factor-κB (NF-κB) activity was not affected by TI-I-1744. In addition, TI-I-174 significantly inhibited activation of c-Jun-N-Terminal kinase (JNK) without affecting ERK1/2 and p38MAPK, indicating that down-regulation of iNOS gene expression by TI-I-174 is mainly attributed by blockade of JNK/AP-1 activation. We also demonstrated that TI-I-174 treatment led to an increase in heme oxygenase-1 (HO-1) expression both at mRNA and protein level. Transfection of siRNA targeting HO-1 reversed TI-I-174-mediated inhibition of nitrite production. Taken together, these results indicate that TI-I-174 suppresses NO production in LPS-stimulated RAW 264.7 macrophages via induction of HO-1 and blockade of AP-1 activation.

Adamantyl arotinoids that inhibit IκB kinase α and IκB kinase β

A series of analogues of the adamantyl arotinoid (AdAr) chalcone MX781 with halogenated benzyloxy substituents at C2' and heterocyclic derivatives replacing the chalcone group were found to inhibit IκBα kinase α (IKKα) and IκBα kinase β (IKKβ) activities. The growth inhibitory capacity of some analogues against Jurkat T cells as well as prostate carcinoma (PC-3) and chronic myelogenous leukemia (K562) cells, which contain elevated basal IKK activity, correlates with the induction of apoptosis and increased inhibition of recombinant IKKα and IKKβ in vitro, pointing toward inhibition of IKK/NFκB signaling as the most likely target of the anticancer activities of these AdArs. While the chalcone functional group present in many dietary compounds has been shown to mediate interactions with IKKβ via Michael addition with cysteine residues, AdArs containing a five-membered heterocyclic ring (isoxazoles and pyrazoles) in place of the chalcone of the parent system are potent inhibitors of IKKs as well, which suggests that other mechanisms for inhibition exist that do not depend on the presence of a reactive α,β-unsaturated ketone.

Regulation of NF-κB activation through a novel PI-3K-independent and PKA/Akt-dependent pathway in human umbilical vein endothelial cells

The transcription factor NF-κB regulates numerous inflammatory diseases, and proteins involved in the NF-κB-activating signaling pathway are important therapeutic targets. In human umbilical vein endothelial cells (HUVECs), TNF-α-induced IκBα degradation and p65/RelA phosphorylation regulate NF-κB activation. These are mediated by IKKs (IκB kinases) viz. IKKα, β and γ which receive activating signals from upstream kinases such as Akt. Akt is known to be positively regulated by PI-3K (phosphoinositide-3-kinase) and differentially regulated via Protein kinase A (PKA) in various cell types. However, the involvement of PKA/Akt cross talk in regulating NF-κB in HUVECs has not been explored yet. Here, we examined the involvement of PKA/Akt cross-talk in HUVECs using a novel compound, 2-methyl-pyran-4-one-3-O-β-D-2',3',4',6'-tetra-O-acetyl glucopyranoside (MPTAG). We observed that MPTAG does not directly inhibit IKK-β but prevents TNF-α-induced activation of IKK-β by blocking its association with Akt and thereby inhibits NF-κB activation. Interestingly, our results also revealed that inhibitory effect of MPTAG on Akt and NF-κB activation was unaffected by wortmannin, and was completely abolished by H-89 treatment in these cells. Thus, MPTAG-mediated inhibition of TNF-α-induced Akt activation was independent of PI-3K and dependent on PKA. Most importantly, MPTAG restores the otherwise repressed activity of PKA and inhibits the TNF-α-induced Akt phosphorylation at both Thr308 and Ser473 residues. Thus, we demonstrate for the first time the involvement of PKA/Akt cross talk in NF-κB activation in HUVECs. Also, MPTAG could be useful as a lead molecule for developing potent therapeutic molecules for diseases where NF-κB activation plays a key role.

Anti-angiogenic activity of the flavonoid precursor 4-hydroxychalcone

Angiogenesis, the growth of new blood vessels, is necessary for cancerous tumors to keep growing and spreading. Suppression of abnormal angiogenesis may provide therapeutic strategies for the treatment of angiogenesis-dependent disorders. In the present study, we describe the in vitro and in vivo anti-angiogenic activities of the flavonoid precursor 4-hydroxychalcone (Q797). This chalcone (22μg/ml) suppressed several steps of angiogenesis, including endothelial cell proliferation, migration and tube formation without showing any signs of cytotoxicity. Moreover, we found a selective effect on activated endothelial cells, in particular with resting endothelial cells and the human epithelial tumor cell lines (HeLa, MCF-7, A549). In addition, Q797 was able to modulate both vascular endothelial growth factor (VEGF)- and basic fibroblast growth factor (FGF)- induced phosphorylation of extracellular signal-regulated kinase (ERK)-1/-2 and Akt kinase. It did not influence the nuclear translocation of p65 subunit of the nuclear factor-κB (NF-κB) when human endothelial cells were stimulated with tumor necrosis factor (TNF)-α. Taken together this indicates that the Q797-mediated inhibition of in vitro angiogenic features of endothelial cells is most likely caused by suppression of growth factor pathways. The potent inhibitory effect of Q797 on bFGF-driven neovascularization was also demonstrated in vivo using the chick chorioallantoic membrane (CAM) assay. In summary, this chalcone could serve as a new leading structure in the discovery of new potent synthetic angiogenesis inhibitors.

Natural and synthetic α,β-unsaturated carbonyls for NF-κB inhibition

BACKGROUND

The nuclear transcription factor NF-κB has gained considerable importance due to its major involvement in inflammation and constitutive activity in malignant cells. It is induced by a variety of stimuli and controls the expression of several proteins involved in biological processes. Numerous natural products and synthesized organic molecules have been reported to inhibit NF-κB and have played an integral role in identifying implicated pathways. Prominent among them are the sesquiterpene lactones, polyphenolic enones and other α,β-unsaturated carbonyl-containing molecules, particularly α-methylene-γ-butyrolactones.

DISCUSSION

This mini-review provides an introductory overview of some of the associated pathways involving NF-κB in cancer and discusses the structures and mode of action of natural α,β-unsaturated carbonyl-containing inhibitors and their synthetic counterparts. A review of the recent methods for the synthesis of α-alkylidene-γ-butyrolactones is also provided, with the aim of arousing the interest of synthetic chemists for the design and development of novel NF-κB inhibitors.

CONCLUSIONS

Modulating damaging effects without harming the inflammatory and immune responses are crucial parameters for developing NF-κB inhibitors. Examination of novel α,β-unsaturated carbonyls and the further discovery of simple methods to prepare such molecules should lead to the identification of site-specific inhibitors.

Trans-Chalcone prevents VEGF expression and retinal neovascularization in the ischemic retina

Retinal neovascularization (RNV) is a critical pathological event and a major cause of blindness. Vascular inflammation and oxidative stress have been shown to play a key role in the induction and progression of RNV. Trans-Chalcone-derived flavonoids have been previously shown to be negative modulators of oxidative stress and inflammatory responses as well as tumor angiogenesis. In this study, we characterized the effects of the flavonoid trans-Chalcone in preventing RNV in a model of ischemic retinopathy. Ischemic retinopathy was induced in neonatal mice subjected to oxygen-induced retinopathy. Trans-Chalcone was administered intra-peritoneum at the dose of 25 mg/kg/day. Vascular density was assessed by morphometric analysis of flat mounted retinas stained with Texas red-Isolectin B4. Western blotting analysis was conducted to determine protein levels of vascular endothelial growth factor (VEGF), inter-cellular adhesion molecule 1 (ICAM-1) and the transcriptional activators' signal transducer and activator of transcription 3 (STAT3) and nuclear factor kappa beta (NF-κB). Treatment with trans-Chalcone significantly inhibited RNV in the ischemic retina, as shown by decreased number of neovascular tufts. Trans-Chalcone also blocked ischemia-induced VEGF and ICAM-1 expression and this effect correlated with inhibition of activated STAT3 and NF-κB. Our results show that trans-Chalcone effectively prevents RNV in the murine retina thus suggesting that Chalcone-derived flavonoids may be beneficial in preventing pathological neovascularization in the ischemic retina.

Effect of sesame lignans on TNF-alpha-induced expression of adhesion molecules in endothelial cells

The expression of cell adhesion molecules (CAMs) has been implicated as one of the most important causes of the development of inflammatory diseases such as atherosclerosis, and, it is speculated that the prevention of it is an effective approach to the control of atherosclerosis. In the present study, we investigated the effect of sesame lignans on the expression of CAMs in human umbilical vein endothelial cells (HUVECs) induced by tumor necrosis factor-alpha (TNF-alpha). Based on cell-ELISA analysis, we found that sesaminol-6-catechol downregulated the TNF-alpha-induced expression of CAMs in a dose-dependent manner. Moreover, these inhibitory effects were caused to be drastically exerted by downregulating the CAM proteins in TNF-alpha-activated HUVECs at transcriptional level. This suggests, that sesaminol-6-catehcol suppresses the expression of CAMs, and may be an active component of sesame lignans.

Effect of caffeic acid on tumor necrosis factor-alpha-induced vascular inflammation in human umbilical vein endothelial cells

Recruitment of specific leukocyte subpopulations at the site of inflammation requires a series of cell adhesion molecules (CAMs)-mediated interactions. The major CAMs, viz., intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin are expressed on endothelium in response to various cytokines. Caffeic acid (CA), a natural phenolic compound from herbs and other sources, has been shown to prevent cardiovascular diseases. We investigated the effect of CA on the expression of CAMs by human umbilical vein endothelial cells (HUVECs) stimulated with tumor necrosis factor (TNF-alpha). Adhesion of monocytes to CA-treated HUVECs was evaluated by co-culture experiments using 2,7-bis(2-carboxyethyl)-5(6)-carboxyfluorescein acetoxymethylester (BCECF-AM) labeling of U937 cells. The expression of adhesion and chemoattractant molecules was evaluated by Western blot and reverse transcription-polymerase chain reaction (RT-PCR), respectively. CA significantly inhibited the TNF-alpha-induced increase in U937 monocyte adhesion to HUVECs as well as decreased the protein and mRNA expression levels of CAMs on HUVECs. CA also inhibited the mRNA expression of monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8). The involvement of nuclear factor (NF)-kappaB in the transcriptional control of CAMs protein was assessed by degradation of inhibitory (I)kappaB and nuclear translocation of NF-kappaB using Western blotting and immunofluorescence staining. CA attenuated TNF-alpha-induced IkappaB degradation and NF-kappaB translocation from cytosol to the nucleus. In conclusion, TNF-alpha-induced NF-kappaB-DNA complex formation was inhibited by CA. CA reduced TNF-alpha-induced endothelial adhesiveness to HUVECs by inhibiting transcription factor activation, and CAMs expression suggesting its potential role in atherosclerosis diseases.

A new chloroquinolinyl chalcone derivative as inhibitor of inflammatory and immune response in mice and rats

The synthetic chalcone derivative 1-(2,4-dichlorophenyl)-3-(3-(6,7-dimethoxy-2-chloroquinolinyl))-2-propen-1-one (CIDQ) was evaluated for its anti-inflammatory, analgesic and immunomodulatory efficacy in-vitro and in-vivo. CIDQ concentration-dependently inhibited the production of nitric oxide (NO) (IC50 4.3 μM) and prostaglandin E2 (PGE2) (IC50 1.8 μM) in RAW 264.7 macrophages stimulated with lipopolysaccharide. Human mononuclear cell proliferation was significantly inhibited by 10 μM CIDQ. Oral administration of CIDQ (10–30 mg kg−1) in the 24-h zymosan-stimulated mouse air-pouch model produced a dose-dependent reduction of cell migration as well as NO and PGE2 levels in exudates. CIDQ (20 mg kg−1, p.o.) inhibited ear swelling and leucocyte infiltration in the delayed-type hypersensitivity response to 2,4-dinitrofluorobenzene in mice. In the rat adjuvant-arthritis model, this compound reduced joint inflammation as well as PGE2 and cytokine levels. In addition, CIDQ displayed analgesic effects in the phenylbenzoquinone-induced abdominal constriction model in mice and in the late phase of the nociceptive response to formalin. Our findings indicated the potential interest of CIDQ in the modulation of some immune and inflammatory conditions.

Possible mechanism of the anti-inflammatory activity of ruscogenin: role of intercellular adhesion molecule-1 and nuclear factor-kappaB

Ruscogenin (RUS), first isolated from Ruscus aculeatus, also a major steroidal sapogenin of traditional Chinese herb Radix Ophiopogon japonicus, has been found to exert significant anti-inflammatory and anti-thrombotic activities. Our previous studies suggested that ruscogenin remarkably inhibited adhesion of leukocytes to a human umbilical vein endothelial cell line (ECV304) injured by tumor necrosis factor-alpha (TNF-alpha) in a concentration-dependent manner. Yet the underlying mechanisms remain unclear. In this study, the in vivo effects of ruscogenin on leukocyte migration and celiac prostaglandin E(2) (PGE(2)) level induced by zymosan A were studied in mice. Furthermore, the effects of ruscogenin on TNF-alpha-induced intercellular adhesion molecule-1 (ICAM-1) expression and nuclear factor-kappaB (NF-kappaB) activation were also investigated under consideration of their key roles in leukocyte recruitment. The results showed that ruscogenin significantly suppressed zymosan A-evoked peritoneal total leukocyte migration in mice in a dose-dependent manner, while it had no obvious effect on PGE(2) content in peritoneal exudant. Ruscogenin also inhibited TNF-alpha-induced over expression of ICAM-1 both at the mRNA and protein levels and suppressed NF-kappaB activation considerably by decreasing NF-kappaB p65 translocation and DNA binding activity. These findings provide some new insights that may explain the possible molecular mechanism of ruscogenin and Radix Ophiopogon japonicus for the inhibition of endothelial responses to cytokines during inflammatory and vascular disorders.

Hormetic dietary phytochemicals

Compelling evidence from epidemiological studies suggests beneficial roles of dietary phytochemicals in protecting against chronic disorders such as cancer, and inflammatory and cardiovascular diseases. Emerging findings suggest that several dietary phytochemicals also benefit the nervous system and, when consumed regularly, may reduce the risk of disorders such as Alzheimer's and Parkinson's diseases. The evidence supporting health benefits of vegetables and fruits provide a rationale for identification of the specific phytochemicals responsible, and for investigation of their molecular and cellular mechanisms of action. One general mechanism of action of phytochemicals that is emerging from recent studies is that they activate adaptive cellular stress response pathways. From an evolutionary perspective, the noxious properties of such phytochemicals play an important role in dissuading insects and other pests from eating the plants. However at the subtoxic doses ingested by humans that consume the plants, the phytochemicals induce mild cellular stress responses. This phenomenon has been widely observed in biology and medicine, and has been described as 'preconditioning' or 'hormesis.' Hormetic pathways activated by phytochemicals may involve kinases and transcription factors that induce the expression of genes that encode antioxidant enzymes, protein chaperones, phase-2 enzymes, neurotrophic factors, and other cytoprotective proteins. Specific examples of such pathways include the sirtuin-FOXO pathway, the NF-kappaB pathway, and the Nrf-2/ARE pathway. In this article, we describe the hormesis hypothesis of phytochemical actions with a focus on the Nrf2/ARE signaling pathway as a prototypical example of a neuroprotective mechanism of action of specific dietary phytochemicals.

Piper longum Linn. Extract inhibits TNF-alpha-induced expression of cell adhesion molecules by inhibiting NF-kappaB activation and microsomal lipid peroxidation

Recruitment of specific leukocyte subpopulations at the site of inflammation requires a series of cell adhesion molecule (CAM)-mediated interactions. The major CAMs, viz., intercellular adhesion molecule-1 (ICAM-1), VCAM-1 and E-selectin are expressed on endothelium in response to various cytokines or bacterial LPS. Here, we have evaluated the effect of Piper longum chloroform extract (PlCE) on TNF-alpha-induced expression of ICAM-1 on endothelial cells and on NADPH-catalyzed rat liver microsomal lipid peroxidation with a view to identify modulators for the expression of CAMs. We demonstrate that PlCE inhibits adhesion of neutrophils to endothelial monolayer. This inhibition is due to the ability of PlCE to significantly block the TNF-alpha-induced expression of CAMs, i.e. ICAM-1, VCAM-1 at 17.5 microg/ml concentration and E-selectin at 15 microg/ml concentration on human umbilical vein endothelial cells. The inhibition of ICAM-1, VCAM-1 and E-selectin by PlCE is mediated through inhibition of NF-kappaB in endothelial cells. To demonstrate the antioxidant activity of PlCE, we showed that PlCE inhibited the NADPH-catalyzed rat liver microsomal lipid peroxidation significantly. These results suggest a possible mechanism of anti-inflammatory as well as antioxidant activity of PlCE.

Inhibition of superoxide anion and elastase release in human neutrophils by 3'-isopropoxychalcone via a cAMP-dependent pathway

1 Chalcone is abundantly present in the plant kingdom and has various biological activities such as anti-inflammatory and antioxidant. In this study, the semisynthetic chalcone derivative, 3'-isopropoxychalcone (H2O7D), was demonstrated to inhibit the generation of superoxide and the release of elastase, as well as to accelerate resequestration of cytosolic calcium in formyl-L-methionyl-L-leucyl-L-phenylalanine-activated human neutrophils. 2 H2O7D displayed no antioxidant or superoxide-scavenging ability, and it failed to alter the subcellular NADPH oxidase activity. 3 H2O7D induced a substantial increase in cAMP but not cGMP levels. The elevation of cAMP formation by H2O7D was inhibited by adenosine deaminase (ADA). Furthermore, The inhibitory effects of H2O7D were reversed by protein kinase (PK)A inhibitors, as well as ADA and a selective A2a-receptor antagonist. 4 H2O7D inhibited phosphodiesterase (PDE) activities, but it did not alter adenylyl cyclase and soluble guanylyl cyclase activities. These results show that the cAMP-elevating effect of H2O7D results from the inhibition of PDE activity and not from the stimulation of cyclase function. Consistent with this, H2O7D potentiated the PGE(1)-caused inhibitory effects and cAMP formation. 5 In summary, these results indicate that the inhibitory effect of H2O7D is cAMP/PKA dependent, and that it occurs through inhibition of cAMP PDE, which potentiates the autocrine functions of endogenous adenosine. Inhibition of respiratory burst and degranulation in human neutrophils may give this drug the potential to protect against the progression of inflammation.

Piperine inhibits TNF-alpha induced adhesion of neutrophils to endothelial monolayer through suppression of NF-kappaB and IkappaB kinase activation

Piperine displays antipyretic, analgesic, insecticidal and anti-inflammatory activities. It is the first amide to be isolated from Piper species. In the process of identifying non-steroidal anti-inflammatory small molecules from the natural sources, we demonstrate here that piperine inhibits adhesion of neutrophils to endothelial monolayer. The inhibition of neutrophils to endothelial monolayer by piperine is due to its ability to block the tumor necrosis factor-alpha (TNF-alpha) induced expression of cell adhesion molecules i.e. ICAM-1 (intercellular adhesion molecule-1), VCAM-1 (vascular cell adhesion molecule-1) and E-selectin as analyzed by cell-ELISA and confirmed by flow cytometry. Further, we demonstrate that inhibition of ICAM-1 by piperine is reversible. As nuclear factor-kappaB (NF-kappaB) is known to control the transcriptional regulation of cell adhesion molecules hence, we measured the effect of piperine on NF-kappaB in the cytoplasm and in the nucleus of endothelial cells. We observed that pretreatment of endothelial cells with piperine blocks the nuclear translocation and activation of NF-kappaB via blocking the phosphorylation and degradation of its inhibitory protein, IkappaBalpha. Piperine blocks the phosphorylation and degradation of IkappaBalpha by attenuating TNF-alpha induced IkappaB kinase activity. These results suggest a possible mechanism of anti-inflammatory activity of piperine. Therefore, piperine or its structural analogues could be used for the development of new anti-inflammatory molecules.

Isoliquiritigenin inhibits IκB kinase activity and ROS generation to block TNF-α induced expression of cell adhesion molecules on human endothelial cells

Isoliquiritigenin (ILTG) is a flavonoid with chalcone structure (4,2',4'-trihydroxychalcone), an active component present in plants like Glycyrrhiza and Dalbergia which showed various biological activities including anti-inflammatory, anti-carcinogenic and antihistamic. As very little is known in regard to the underlying mechanism involved in explaining the various activities of the compound, we carried out a detailed study on the effect of ILTG on the expression of cell adhesion molecules on human primary endothelial cells. We demonstrate here that ILTG inhibits TNF-alpha induced adhesion of neutrophils to endothelial monolayer by blocking the expression of ICAM-1, VCAM-1 and E-selectin. Since NF-kappaB is a major transcription factor involved in the transcriptional regulation of cell adhesion molecules, thus we studied the status of NF-kappaB activation in ILTG treated endothelial cells. We demonstrate that ILTG inhibits the translocation and activation of nuclear factor-kappaB (NF-kappaB) by blocking the phosphorylation and subsequent degradation of IkappaBalpha. As oxidative stress is also known to regulate the activation of NF-kappaB to modulate TNF-alpha signaling cascade, we tested the effect of ILTG on reactive oxygen species (ROS). We found that it inhibits TNF-alpha induced ROS production in endothelial cells. These results have important implications for using ILTG or its derivatives towards the development of effective anti-inflammatory molecules.

Evaluation of the anti-inflammatory and analgesic activity of Me-UCH9, a dual cyclooxygenase-2/5-lipoxygenase inhibitor

Recently, we reported the dual inhibition of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) activity by some phenylsulphonyl urenyl chalcone derivatives. 2,4-dichloro-4'N[N'(4''methylphenylsulphonyl)urenyl] chalcone (Me-UCH9), was selected in the present study to determine its potential anti-inflammatory and analgesic effect after oral administration in several animal models related to the activation of COX-2 and 5-LO pathways. In the zymosan stimulated mouse air pouch model, Me-UCH9, reduced in a dose-dependent manner leukotriene B(4) (LTB(4)) levels in pouch exudates obtained at 4 h, as well as prostaglandin E(2) (PGE(2)) generated through COX-2 activation at 24 h. Tumor necrosis factor alpha (TNF-alpha) and myeloperoxidase activity were also strongly inhibited in this model. Me-UCH9 significantly reduced granuloma size and vascular index determined in the murine air pouch granuloma model of angiogenesis. In the carrageenan-induced paw edema, this compound inhibited inflammatory response and pain, as well as PGE(2) and LTB(4) content in paw edematous fluid. Analgesic properties were corroborated in the murine phenyl-p-benzoquinone-induced writhing test. Finally, Me-UCH9 exerted anti-inflammatory effects in the chronic model of rat adjuvant-induced arthritis, both inhibiting paw swelling and reducing PGE(2) content. Our findings confirm that Me-UCH9 can modulate inflammatory and nociceptive responses in relation to the dual inhibition of COX-2 and 5-LO activities presented by this compound.

A chromone analog inhibits TNF-alpha induced expression of cell adhesion molecules on human endothelial cells via blocking NF-kappaB activation

The interaction between leukocytes and the vascular endothelial cells (EC) via cellular adhesion molecules plays an important role in various inflammatory and immune diseases. The molecules that block these interactions have been targeted as potential therapeutic targets for acute and chronic inflammatory diseases. In an effort to develop potent cell adhesion molecule inhibitors, a series of chromone derivatives bearing alkoxycarbonylvinyl unit at the C-3 position, that is, the chromones 8a-d and 9a-d, were designed and synthesized, and evaluated for their ICAM-1 inhibitory activity on human endothelial cells as well as their effect on NADPH-catalyzed rat microsomal lipid peroxidation. A structure-activity relationship was established and we found that length of the alkyl moiety of the chromone-3-yl-acrylate is important for this activity. Further, we found that incorporation of unsaturation in the alcohol moiety increases the potential of the compound for the inhibition of TNF-alpha induced expression of ICAM-1 and also for the inhibition of lipid peroxidation. Out of the screened compounds, the most potent compound ethyl trans-3-(4-oxo-4H-1-benzopyran-3-yl)-acrylate (8a) was taken for further study. We have found that compound 8a also significantly inhibited the TNF-alpha induced expression of VCAM-1 and E-selectin, which play key roles in various inflammatory diseases. This inhibition was found to be concentration dependent. The functional consequences of inhibiting cell adhesion molecules were studied by performing cell-adhesion assay. We found that compound 8a significantly blocks the adhesion of neutrophils to endothelial monolayer. To elucidate the molecular mechanism of inhibition of cell adhesion molecules, we investigated the status of nuclear transcription factor-kappaB (NF-kappaB) and were able to establish that compound 8a significantly blocked the TNF-alpha induced activation of NF-kappaB.

Chalcone inhibits the activation of NF-kappaB and STAT3 in endothelial cells via endogenous electrophile

Chalcone, an alpha,beta-unsaturated flavonoid, possesses anti-inflammatory properties. In our present study, we have demonstrated chalcone inhibited IL-6- and LPS-induced ICAM-1 gene expression. In adhesion assay, chalcone reduced the LPS-induced adhesion of THP-1 cells to endothelial cells (ECs). Chalcone was found to abrogate the activation of STAT3 and NF-kappaB in a dose- and time-dependent manner, in IL-6- and LPS-treated ECs. Other flavonoids, quercetin and cyanidin, which lack alpha,beta-unsaturated carbonyl group, showed weaker or no inhibitory effect on both IL-6-induced STAT3 phosphorylation and LPS-induced p65 translocation. However, the electrophilic compounds curcumin and crotonaldehyde, which also contain an alpha,beta-unsaturated carbonyl moiety, mimic the inhibitory effects of chalcone with different efficiencies. In addition, N-acetyl-L-cysteine (NAC) could reverse the inhibition of STAT3 phosphorylation when preincubated with chalcone. The use of buthionine sulfoximine (BSO) to decrease intracellular GSH levels further enhanced the effects of chalcone. On the other hand, in ECs treated with BSO only no abrogation of IL-6-induced STAT3 phosphorylation was observed. We also found that chalcone could reduce the GSH level in vitro. Furthermore, the cellular GSH levels were rapidly reduced after 25 microM chalcone treatment. Following 6 h exposure, however, chalcone treatment rescued the GSH levels in ECs, coincident with the inhibition of STAT3 and NF-kappaB activation. In contrast, chalcone induced expression of thioredoxin reductase and heme-oxygenase genes after prolonged treatment. Furthermore, chalcone upregulated the levels of the transcription factor Nrf2 in nuclear extracts and increased antioxidant response element (ARE)-luciferase activity and thioredoxin reductase promoter activity. Hence, our present findings indicate that chalcone suppresses both IL-6- and LPS-induced signaling pathways through the thiol-dependent intracellular redox state. In addition, chalcone may provide distinct cytoprotective effects at different durations of pretreatment.

Association of TNF haplotypes with asthma, serum IgE levels, and correlation with serum TNF-alpha levels

Both biochemical and genetic evidence have implicated the genes for TNF-alpha (TNFA) and lymphotoxin-alpha (LTA) in atopic asthma. Here, we report for the first time the association of their genotypes and haplotypes with atopic asthma in Indian populations. We genotyped seven single nucleotide polymorphisms, encompassing the two genes, in patients and control subjects in two independent cohorts. Serum TNF-alpha levels of selected individuals were measured and correlated with genotypes and haplotypes. The A allele of the TNFA-863C > A polymorphism was associated with reduced risk of asthma (P = 0.002 and 0.007 in Cohorts A and B, respectively), reduced TsIgE levels (P = 0.0024 and P = 0.0029 in Cohorts A and B, respectively), and reduced serum TNF-alpha levels (P < 0.05). A marginal association was also observed for LTA_NcoI polymorphism with asthma and TsIgE levels. Furthermore, analysis using HAPLO. STATS showed significant differences in the major haplotype frequencies (> 3%) between patients and control subjects (P = 0.002 and P = 0.006 for Cohorts A and B, respectively). Individually, the haplotype GATCCG was the most frequent in patients (P = 0.0029 and P = 0.0025 for Cohorts A and B, respectively), and was associated with high TsIgE and serum TNF-alpha levels, whereas AACACG was the most frequent in the control subjects (P = 0.0032 and P = 0.022 for Cohorts A and B, respectively), and was associated with low TsIgE and serum TNF-alpha levels. We also report here that the C > A substitution at position -863 of the TNFA influences the binding of nuclear proteins in electrophoretic mobility shift assay experiments. Thus, the TNFA-863C > A polymorphism in the promoter region of TNFA may influence TNF-alpha expression and affect TsIgE levels and susceptibility to asthma.

Heme oxygenase-1 mediates the anti-inflammatory actions of 2′-hydroxychalcone in RAW 264.7 murine macrophages

Chalcones are a group of plant-derived polyphenolic compounds that belong to the flavonoids family, and possess a wide variety of cytoprotective and modulatory functions. Chalcones exert their cytoprotective actions via activation of specific transcriptional factors and upregulation of endogenous defensive pathways, such as phase II enzymes and the stress protein heme oxygenase-1 (HO-1). In this study, we investigated the anti-inflammatory action of 2′-hydroxychalcone (2-HC) in a model of lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages and examined the role of HO-1 in this process. Our results demonstrate that 2-HC potently induces HO-1 expression and markedly reduces LPS-mediated nitrite and TNF-α production. These effects are accompanied by inhibition of inducible nitric oxide synthase protein expression and abolished by blockade of heme oxygenase activity with either tin protoporphyrin IX or HO-1 small interfering RNA. By using a pharmacological approach and siRNA technology, we also found that phosphatidylinositol 3-kinase is a major cellular mediator in 2-HC-induced HO-1 expression. These findings strongly suggest that 2-HC exerts anti-inflammatory actions via activation of the HO-1 pathway and help to elucidate the mechanisms underlying the potential therapeutic value of chalcones.

Inhibition of TNFalpha-induced activation of nuclear factor kappaB by kava (Piper methysticum) derivatives

The inducible transcription factor nuclear factor kappaB (NF-kappaB) plays a central role in the regulation of immune, inflammatory and carcinogenic responses. While normal activation of NF-kappaB is required for cell survival and immunity, its deregulated expression is a characteristic of inflammatory and infectious diseases. In this study, we investigated the molecular mechanisms induced by lactones and chalcones isolated from Fijian kava (Piper methysticum) used in traditional medicine against urinary tract infections and asthma. In order to understand underlying regulatory mechanisms, inhibition of both NF-kappaB-driven reporter gene expression and TNFalpha-induced binding of NF-kappaB to a consensus response element was achieved at concentrations of 320 microM (flavokavain A), 175 microM (flavokavain B) and 870 microM (kavain and dihydrokavain). Moreover, kavain and flavokavains A and B treatment led to inhibition of both inhibitor of kappaB (IkappaB) degradation and subsequent translocation of p50 and p65 NF-kappaB subunits from the cytoplasm to the nucleus as shown by Western blot analysis. Additionally, kinase selectivity screening demonstrates that flavokavain A, but not kavain, nor flavokavain B, inhibits the IkappaB kinase (IKK) as well as PRAK (p38-regulated/activated kinase), MAPKAP-K3 (MAPK-activated protein kinase 3), DYRK1A (dual-specificity tyrosine-phosporylated and regulated kinase 1A) and Aurora B. Altogether, these results give a first insight into anti-inflammatory mechanisms triggered by traditionally used chemopreventive kava compounds.

Polarized helper T cells in tubercular pleural effusion: phenotypic identity and selective recruitment

Containment of Mycobacterium tuberculosis critically depends on orchestrated generation of Th1 cells and their selective recruitment at the pathologic sites. Understanding the mechanism involved in this process is important for defining better intervention strategies. We investigated the surface phenotype of Th1 cells and the role of chemotactic factors in their selective recruitment in tuberculosis pleural effusion and tuberculin site. Memory T cells obtained from the pleural fluid expressed a battery of homing receptors such as CD11a, CCR5 and CXCR3. Similar expression profile was noted on T cells infiltrating the tuberculin site. Expression of their respective ligands such as ICAM-1, RANTES, MIP1-alpha, Mig and IP-10 were detected at pathologic sites. In vitro assay of T cell adherence to activated human umbilical vein endothelial cells (HUVEC) expressing chemotactic ligands suggests an important role of these homing molecules in their selective trafficking. Here, we demonstrate a hierarchy of CXCR3 in effector cell adhesion to HUVEC in vitro, although CD11a and CCR5 were also observed to mediate cell adhesion in an additive fashion. Findings of the present study provide mechanistic insights into the critical events of T cell trafficking in tuberculosis and may help designing better therapeutic modalities.

Blockade of nuclear factor-kappaB signaling pathway and anti-inflammatory activity of cardamomin, a chalcone analog from Alpinia conchigera

Nuclear factor-kappaB (NF-kappaB) and the signaling pathways that regulate its activity have become a focal point for intense drug discovery and development efforts. NF-kappaB regulates the transcription of a large number of genes, particularly those involved in immune, inflammatory, and antiapoptotic responses. In our search for NF-kappaB inhibitors from natural resources, we identified cardamomin, 2',4'-dihydroxy-6'-methoxychalcone, as an inhibitor of NF-kappaB activation from Alpinia conchigera Griff (Zingiberaceae). In present study, we demonstrated the effect of cardamomin on NF-kappaB activation in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and LPS-induced mortality. This compound significantly inhibited the induced expression of NF-kappaB reporter gene by LPS or tumor necrosis factor (TNF)-alpha in a dose-dependent manner. LPS-induced production of TNF-alpha and NO as well as expression of inducible nitric-oxide synthase and cyclooxygenase-2 was significantly suppressed by the treatment of cardamomin in RAW264.7 cells. Also, cardamomin inhibited not only LPS-induced degradation and phosphorylation of inhibitor kappaBalpha (IkappaBalpha) but also activation of inhibitor kappaB (IkappaB) kinases and nuclear translocation of NF-kappaB. Further analyses revealed that cardamomin did not directly inhibit IkappaB kinases, but it significantly suppressed LPS-induced activation of Akt. Moreover, cardamomin suppressed transcriptional activity and phosphorylation of Ser536 of RelA/p65 subunit of NF-kappaB. However, this compound did not inhibit LPS-induced activation of extracellular signal-regulated kinase and stress-activated protein kinase/c-Jun NH(2)-terminal kinase, but significantly impaired activation of p38 mitogen-activated protein kinase. We also demonstrated that pretreatment of cardamomin rescued C57BL/6 mice from LPS-induced mortality in conjunction with decreased serum level of TNF-alpha. Together, cardamomin could be valuable candidate for the intervention of NF-kappaB-dependent pathological condition such as inflammation.

The plant polyphenol butein inhibits testosterone-induced proliferation in breast cancer cells expressing aromatase

Chalcones are precursor compounds for flavonoid synthesis in plants, and they can also be synthesized in laboratory. Previous study has documented some of the pharmacological applications of these compounds. Estrogen has long been associated with the initiation and promotion of breast cancer. Inhibiting estrogen synthesis can be effective in the prevention and treatment of the disease. Since most breast cancers received estrogen supplied from local tissues, we employed a breast cancer cell line expressing aromatase to screen for the inhibitory potentials of five hydroxychalcones, i.e. 2-hydroxychalcone, 2'-hydroxychalcone, 4-hydroxychalcone, 4,2',4'-trihydroxy-chalcone (isoquiritigenin), 3,4,2',4'-tetrahydroxychalcone (butein). In the preliminary results, butein was found to be the strongest inhibitor among the tested compounds, and its IC(50) value was 3.75 microM. Subsequent enzyme kinetic study revealed that butein acted on aromatase with a mixed type of inhibition and the K(i) value was determined to be 0.32 microM. Cell proliferation assay indicated that the cell number increased by 10 nM-testosterone treatment was significantly reduced by 5 microM butein, and the administration of flutamide could not reverse the effect. The present study illustrated that butein was an aromatase inhibitor and a potential natural alternative for the chemoprevention or therapy of breast cancer.