3,3'-Diindolylmethane suppresses the inflammatory response to lipopolysaccharide in murine macrophages

3,3'-Diindolylmethane attenuates LPS-mediated acute liver failure by regulating miRNAs to target IRAK4 and suppress Toll-like receptor signalling

BACKGROUND AND PURPOSE

Acute liver failure (ALF) is a severe and potentially lethal clinical syndrome. 3,3'-Diindolylmethane (DIM) is a natural plant-derived compound with anti-cancer activities. Recently, DIM has also been shown to have anti-inflammatory properties. Here, we tested the hypothesis that DIM would suppress endotoxin-induced ALF.

EXPERIMENTAL APPROACH

We investigated the therapeutic potential of DIM in a mouse model of D-galactosamine/Lipopolysaccharide (GalN/LPS)-induced ALF. The efficacy of DIM treatment was assessed by survival, liver histopathology, serum levels of alanine transaminase, pro-inflammatory cytokines and number of activated liver macrophages. Effects of DIM on the expression of two miRNAs, 106a and 20b, and their predicted target gene were measured by qRT-PCR and Western blotting. Effects of DIM on the release of TNF-α from RAW264.7 macrophages transfected with mimics of these miRNAs and activated by LPS was assessed by elisa.

KEY RESULTS

DIM treatment protected mice from ALF symptoms and reduced the number of activated liver macrophages. DIM increased expression of miR-106a and miR-20b in liver mononuclear cells and decreased expression of their predicted target gene IL-1 receptor-associated kinase 4 (IRAK4), involved in signalling from Toll-like receptor 4 (TLR4). In vitro transfection of RAW264.7 cells using miRNA mimics of miR-106a and 20b decreased expression of IRAK4 and of TNF-α secretion, following LPS stimulation.

CONCLUSIONS AND IMPLICATIONS

DIM attenuated GalN/LPS-induced ALF by regulating the expression of unique miRNAs that target key molecules in the TLR4 inflammatory pathway. DIM may represent a potential novel hepatoprotective agent.

Oxyresveratrol suppresses lipopolysaccharide-induced inflammatory responses in murine macrophages

Excessive inflammation is considered a critical factor in many human diseases. Oxyresveratrol(trans-2,3',4,5'-tetrahydroxystilbene), a natural hydroxystilbene, has been shown to possess antioxidant and free radical-scavenging activity. In this study, we investigated the effects of oxyresveratrol (OxyR) on the lipopolysaccharide (LPS)-induced production of inflammatory cytokines and mediators and further explored the mechanism of action in RAW264.7 murine macrophage cell line. Production of nitric oxide (NO), prostaglandin E2 (PGE2), messenger RNA (mRNA) and protein expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin 6 (IL-6), and granulocyte macrophage colony-stimulating factor (GM-CSF), phosphorylation of mitogen-activated protein kinases (MAPKs; extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38), and the activation of nuclear factor κ-light chain enhancer of activated B cells (NFκB) with OxyR were assayed in LPS-stimulated RAW264.7 cells. OxyR inhibited the productions of NO, PGE2, IL-6, and GM-CSF significantly in LPS-stimulated RAW264.7 cells. OxyR suppressed mRNA and protein expressions of iNOS, COX-2, IL-6, and GM-CSF in LPS-stimulated RAW264.7 cells. OxyR suppressed the phosphorylation of Akt and JNK and p38 MAPKs and the translocation of NFκB p65 subunit into the nucleus. These results indicate that OxyR inhibits LPS-stimulated inflammatory responses though the blocking of MAPK and NFκB signaling pathway in macrophages, and suggest that OxyR possesses anti-inflammatory effects.

Berteroin present in cruciferous vegetables exerts potent anti-inflammatory properties in murine macrophages and mouse skin

Berteroin (5-methylthiopentyl isothiocyanate) is a sulforaphane analog present in cruciferous vegetables, including Chinese cabbage, rucola salad leaves, and mustard oil. We examined whether berteroin exerts anti-inflammatory activities using lipopolysaccharide (LPS)-stimulated Raw 264.7 macrophages and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse skin inflammation models. Berteroin decreased LPS-induced release of inflammatory mediators and pro-inflammatory cytokines in Raw 264.7 macrophages. Berteroin inhibited LPS-induced degradation of inhibitor of κBα (IκBα) and nuclear factor-κB p65 translocation to the nucleus and DNA binding activity. Furthermore, berteroin suppressed degradation of IL-1 receptor-associated kinase and phosphorylation of transforming growth factor β activated kinase-1. Berteroin also inhibited LPS-induced phosphorylation of p38 MAPK, ERK1/2, and AKT. In the mouse ear, berteroin effectively suppressed TPA-induced edema formation and down-regulated iNOS and COX-2 expression as well as phosphorylation of AKT and ERK1/2. These results demonstrate that berteroin exhibits potent anti-inflammatory properties and suggest that berteroin can be developed as a skin anti-inflammatory agent.

Attenuation of Carcinogenesis and the Mechanism Underlying by the Influence of Indole-3-carbinol and Its Metabolite 3,3'-Diindolylmethane: A Therapeutic Marvel

Rising evidence provides credible support towards the potential role of bioactive products derived from cruciferous vegetables such as broccoli, cauliflower, kale, cabbage, brussels sprouts, turnips, kohlrabi, bok choy, and radishes. Many epidemiological studies point out that Brassica vegetable protects humans against cancer since they are rich sources of glucosinolates in addition to possessing a high content of flavonoids, vitamins, and mineral nutrients. Indole-3-carbinol (I3C) belongs to the class of compounds called indole glucosinolate, obtained from cruciferous vegetables, and is well-known for tits anticancer properties. In particular, I3C and its dimeric product, 3,3'-diindolylmethane (DIM), have been generally investigated for their value against a number of human cancers in vitro as well as in vivo. This paper reviews an in-depth study of the anticancer activity and the miscellaneous mechanisms underlying the anticarcinogenicity thereby broadening its therapeutic marvel.

Multiple therapeutic and preventive effects of 3,3'-diindolylmethane on cancers including prostate cancer and high grade prostatic intraepithelial neoplasia

Cruciferous vegetables belong to the plant family that has flowers with four equal-sized petals in the pattern of a crucifer cross. These vegetables are an abundant source of dietary phytochemicals, including glucosinolates and their hydrolysis products such as indole-3-carbinol (I3C) and 3,3′-diindolylmethane (DIM). By 2013, the total number of natural glucosinolates that have been documented is estimated to be 132. Recently, cruciferous vegetable intake has garnered great interest for its multiple health benefits such as anticancer, antiviral infections, human sex hormone regulation, and its therapeutic and preventive effects on prostate cancer and high grade prostatic intraepithelial neoplasia (HGPIN). DIM is a hydrolysis product of glucosinolates and has been used in various trials. This review is to provide an insight into the latest developments of DIM in treating or preventing both prostate cancer and HGPIN.

Benzyl isothiocyanate suppresses high-fat diet-stimulated mammary tumor progression via the alteration of tumor microenvironments in obesity-resistant BALB/c mice

We previously reported that a high-fat diet (HFD) and M2-macrophages induce changes in tumor microenvironments and stimulate tumor growth and metastasis of 4T1 mammary cancer cells in BALB/c mice. In this study, we attempted to determine whether benzyl isothiocyanate (BITC) inhibits HFD-induced changes in tumor progression and in tumor microenvironments. Four groups of female BALB/c mice (4-week-old) were fed on a control diet (CD, 10 kcal% fat) and HFD (60 kcal% fat) containing BITC (0, 25, or 100 mg/kg diet) for 20 weeks. Following 16 weeks of feeding, 4T1 cells (5×10(4) cells) were injected into the mammary fat pads, and animals were killed 30 d after the injection. HFD feeding increased solid tumor growth and the number of tumor nodules in the lung and liver, as compared to the CD group, and these increases were inhibited by BITC supplementation. The number of lipid vacuoles, CD45+ leukocytes and CD206+ M2-macrophages, expression of Ki67, levels of cytokines/chemokines, including macrophage-colony stimulating factor (M-CSF) and monocyte chemoattractant protein-1, and mRNA levels of F4/80, CD86, Ym1, CD163, CCR2, and M-CSF receptor were increased in the tumor tissues of HFD-fed mice, and these increases were inhibited by BITC supplementation. In vitro culture results demonstrated that BITC inhibited macrophage migration as well as lipid droplet accumulation in 3T3-L1 cells. These results suggest that suppression of lipid accumulation and macrophage infiltration in tumor tissues may be one of the mechanisms by which BITC suppresses tumor progression in HFD-fed mice.

Effects of sulforaphane and 3,3'-diindolylmethane on genome-wide promoter methylation in normal prostate epithelial cells and prostate cancer cells

Epigenetic changes, including aberrant DNA methylation, result in altered gene expression and play an important role in carcinogenesis. Phytochemicals such as sulforaphane (SFN) and 3,3'-diindolylmethane (DIM) are promising chemopreventive agents for the treatment of prostate cancer. Both have been shown to induce re-expression of genes, including tumor suppressor genes silenced in cancer cells, via modulation of epigenetic marks including DNA methylation. However, it remained unclear the effects SFN and DIM on DNA methylation at a genomic scale. The goal of this study was to determine the genome-wide effects of SFN and DIM on promoter methylation in normal prostate epithelial cells and prostate cancer cells. Both SFN and DIM treatment decreased DNA methyltransferase expression in normal prostate epithelial cells (PrEC), and androgen-dependent (LnCAP) and androgen-independent (PC3) prostate cancer cells. The effects of SFN and DIM on promoter methylation profiles in normal PrEC, LnCAP and PC3 prostate cancer cells were determined using methyl-DNA immunoprecipitation followed by genome-wide DNA methylation array. We showed widespread changes in promoter methylation patterns, including both increased and decreased methylation, in all three prostate cell lines in response to SFN or DIM treatments. In particular, SFN and DIM altered promoter methylation in distinct sets of genes in PrEC, LnCAP, and PC3 cells, but shared similar gene targets within a single cell line. We further showed that SFN and DIM reversed many of the cancer-associated methylation alterations, including aberrantly methylated genes that are dysregulated or are highly involved in cancer progression. Overall, our data suggested that both SFN and DIM are epigenetic modulators that have broad and complex effects on DNA methylation profiles in both normal and cancerous prostate epithelial cells. Results from our study may provide new insights into the epigenetic mechanisms by which SFN and DIM exert their cancer chemopreventive effects.

3,3'-Diindolylmethane inhibits lipopolysaccharide-induced microglial hyperactivation and attenuates brain inflammation

Recent studies have revealed that microglial hyperactivation and neuroinflammation are implicated in development and progression of neurodegenerative diseases. In this study, we examined the beneficial effects of 3,3'-diindolylmethane (DIM) and indole-3-carbinol (I3C), dietary components found in cruciferous vegetables, on brain inflammation. DIM, a major metabolite of I3C, suppressed lipopolysaccharide (LPS)-induced expression of inducible nitric oxide synthase and cyclooxygenase-2 in BV-2 microglia, but I3C did not. DIM, but not I3C, attenuated DNA-binding activity of nuclear factor-κB (NF-κB) and phosphorylation of inhibitor of κB, suggesting that DIM might inhibit microglial hyperactivation by attenuating inflammatory transcription factor NF-κB. In addition, DIM, but not I3C, protected primary cortical neurons from inflammatory toxicity induced by the conditioned media from LPS-stimulated BV-2 microglia, indicating that DIM might attenuate microglial hyperactivation-mediated neuronal death. In an in vivo model of neuroinflammation, DIM suppressed LPS-induced brain inflammation in mouse hippocampus, as determined by the number of Iba-1-positive cells and the mRNA expression of F4/80. Taken together, these results suggest that DIM may have beneficial potential against brain inflammation and neurodegenerative diseases through the negative regulation of the NF-κB signal pathway in microglia.

Erucin exerts anti-inflammatory properties in murine macrophages and mouse skin: possible mediation through the inhibition of NFκB signaling

Erucin, an isothiocyanate, is a hydrolysis product of glucoerucin found in arugula and has recently been reported to have anti-cancer properties in various cancer cells. In this study, we assessed the anti-inflammatory effects of erucin and the underlying mechanisms, using lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophages and 12-O-tetradecanoylphorbol-13-acetate-treated mouse skin. In RAW 264.7 cells, erucin (2.5, 5 μmol/L) inhibited LPS-induced production of nitric oxide and prostaglandin E₂. Erucin inhibited LPS-induced degradation of the inhibitor of κBα and translocation of p65 to the nucleus and, subsequently, reduced LPS-induced nuclear factor κB (NFκB) DNA binding activities, as well as the transcriptional activity of NFκB, leading to the decreased expression of NFκB-target genes, including tumor necrosis factor-α, interleukin (IL)-6, IL-1β, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, as well as transcriptional activity of iNOS and COX-2. In mice, erucin (100, 300 nmoles) treatment significantly inhibited phorbol ester-induced formation of ear edema and expression of iNOS and COX-2 proteins. These results indicate that erucin exerts a potent anti-inflammatory activity by inhibiting the pro-inflammatory enzymes and cytokines, which may be mediated, at least in part, via the inhibition of NFκB signaling.

Licorice-derived dehydroglyasperin C increases MKP-1 expression and suppresses inflammation-mediated neurodegeneration

Recent studies have demonstrated that microglial hyperactivation-mediated neuroinflammation is involved in the pathogenesis of several neurodegenerative diseases. Thus, inhibiting microglial production of the neurotoxic mediator tumor necrosis factor-α (TNF-α) is considered a promising strategy to protect against neurodegeneration. Here, we investigated the inhibitory effect of licorice-derived dehydroglyasperin C (DGC) on lipopolysaccharide (LPS)-induced TNF-α production and inflammation-mediated neurodegeneration. We found that DGC pre-treatment attenuated TNF-α production in response to LPS stimulation of BV-2 microglia. DGC pre-treatment attenuated LPS-induced inhibitor of κB-α (IκB-α) and p65 phosphorylation and decreased the DNA binding activity of nuclear factor-κB (NF-κB). DGC pre-treatment also inhibited LPS-mediated phosphorylation of p38 mitogen-activated protein kinases (MAPKs) and extracellular signal-regulated kinase (ERK). Interestingly, DGC treatment of BV-2 microglia significantly increased MAPK phosphatase 1 (MKP-1) mRNA and protein expression, which is a phosphatase of p38 MAPK and ERK, suggesting that the DGC-mediated increase in MKP-1 expression might inhibit LPS-induced MAPKs and NF-κB activation and further TNF-α production. We also found that LPS-mediated microglial neurotoxicity can be attenuated by DGC. The addition of conditioned media (CM) from DGC- and LPS-treated microglia to neurons helped maintain healthy cell body and neurite morphology and increased the number of microtubule-associated protein 2-positive cells and the level of synaptophysin compared to treatment with CM from LPS-treated microglia. Taken together, these data suggest that DGC isolated from licorice may inhibit microglia hyperactivation by increasing MKP-1 expression and acting as a potent anti-neurodegenerative agent.

Antioxidant function of isoflavone and 3,3'-diindolylmethane: are they important for cancer prevention and therapy?

SIGNIFICANCE

Oxidative stress has been mechanistically linked with aging and chronic diseases, including cancer. In fact, oxidative stress status, chronic disease-related inflammation, and cancer occurred in the aging population are tightly correlated. It is well known that the activation of nuclear factor kappa B (NF-κB) plays important roles in oxidative stress, inflammation, and carcinogenesis. Therefore, targeting NF-κB is an important preventive or therapeutic strategy against oxidative stress, inflammation, and cancer.

RECENT ADVANCES

A variety of natural compounds has been found to reduce oxidative stress through their antioxidant activity. Among them, isoflavone, indole-3-carbinol (I3C), and its in vivo dimeric compound 3,3'-diindolylmethane (DIM) have shown their promising effects on the inhibition of NF-κB with corresponding reduction of oxidative stress.

CRITICAL ISSUES

It has been found that isoflavone, I3C, and DIM could inhibit cancer development and progression by regulating multiple cellular signaling pathways that are related to oxidative stress and significantly deregulated in cancer.

FUTURE DIRECTIONS

The antioxidative and anticancer effects of these natural agents make them strong candidates for chemoprevention and/or therapy against human malignancies. However, more clinical trials are needed to evaluate the effects of isoflavone and DIM for the prevention of cancer development and also for the treatment of cancer either alone or in combination with conventional cancer therapeutics.

Mechanisms by which licochalcone e exhibits potent anti-inflammatory properties: studies with phorbol ester-treated mouse skin and lipopolysaccharide-stimulated murine macrophages

In this study we found that licochalcone E (LicE), a recently isolated retrochalcone from Glycyrrhiza inflata, exhibits potent anti-inflammatory effects in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema and lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophage models. Topical application of LicE (0.5–2 mg) effectively inhibited TPA-induced (1) ear edema formation; (2) phosphorylation of stress-activated protein kinase/c-Jun-N-terminal kinase (SAPK/JNK), c-Jun, and extracellular signal regulated kinase 1/2; and (3) expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 proteins in mouse skin. The treatment of RAW 264.7 cells with LicE (2.5–7.5 μmol/L) induced a profound reduction in LPS-induced (1) release of NO and prostaglandin E₂; (2) mRNA expression and secretion of interleukin (IL)-6, IL-1β and tumor necrosis factor-α; (3) promoter activity of iNOS and COX-2 and expression of their corresponding mRNAs and proteins; (4) activation of AKT, p38 mitogen activated protein kinase (MAPK), SAPK/JNK and c-Jun; (5) phosphorylation of inhibitor of κB (IκB) kinase-αβ and IκBα, degradation of IκBα, translocation of p65 (RelA) to the nucleus and transcriptional activity of nuclear factor (NF)-κB; and (6) transcriptional activity of activator protein (AP)-1. These results indicate that the LicE inhibition of NF-κB and AP-1 transcriptional activity through the inhibition of AKT and MAPK activation contributes to decreases in the expression of pro-inflammatory cytokines and the inducible enzymes iNOS and COX-2.

3,3'-Diindolylmethane protects against cardiac hypertrophy via 5'-adenosine monophosphate-activated protein kinase-α2

Purpose

3,3′-Diindolylmethane (DIM) is a natural component of cruciferous plants. It has strong antioxidant and anti-angiogenic effects and promotes the apoptosis of a variety of tumor cells. However, little is known about the critical role of DIM on cardiac hypertrophy. In the present study, we investigated the effects of DIM on cardiac hypertrophy.

Methods

Multiple molecular techniques such as Western blot analysis, real-time PCR to determine RNA expression levels of hypertrophic, fibrotic and oxidative stress markers, and histological analysis including H&E for histopathology, PSR for collagen deposition, WGA for myocyte cross-sectional area, and immunohistochemical staining for protein expression were used.

Results

In pre-treatment and reverse experiments, C57/BL6 mouse chow containing 0.05% DIM (dose 100 mg/kg/d DIM) was administered one week prior to surgery or one week after surgery, respectively, and continued for 8 weeks after surgery. In both experiments, DIM reduced to cardiac hypertrophy and fibrosis induced by aortic banding through the activation of 5′-adenosine monophosphate-activated protein kinase-α2 (AMPKα2) and inhibition of mammalian target of the rapamycin (mTOR) signaling pathway. Furthermore, DIM protected against cardiac oxidative stress by regulating expression of estrogen-related receptor-alpha (ERRα) and NRF2 etc. The cardioprotective effects of DIM were ablated in mice lacking functional AMPKα2.

Conclusion

DIM significantly improves left ventricular function via the activation of AMPKα2 in a murine model of cardiac hypertrophy.

Moringa fruit inhibits LPS-induced NO/iNOS expression through suppressing the NF-κ B activation in RAW264.7 cells

In this study, we evaluated the anti-inflammatory effects of moringa (Moringa oleifera Lam.), a natural biologically active substance, by determining its inhibitory effects on pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated macrophage RAW264.7 cells. Extracts from different parts of moringa (root, leaf, and fruit) reduced LPS-induced nitric oxide (NO) release in a dose-dependent manner. The moringa fruit extract most effectively inhibited LPS-induced NO production and levels of inducible nitric oxide synthase (iNOS). The moringa fruit extract also was shown to suppress the production of inflammatory cytokines including IL-1β, TNF-α, and IL-6. Furthermore, moringa fruit extract inhibited the cytoplasmic degradation of I κ B -α and the nuclear translocation of p65 proteins, resulting in lower levels of NF -κ B transactivation. Collectively, the results of this study demonstrate that moringa fruit extract reduces the levels of pro-inflammatory mediators including NO , IL-1β, TNF-α, and IL-6 via the inhibition of NF -κ B activation in RAW264.7 cells. These findings reveal, in part, the molecular basis underlying the anti-inflammatory properties of moringa fruit extract.

Biological features of core networks that result from a high-fat diet in hepatic and pulmonary tissues in mammary tumour-bearing, obesity-resistant mice

We previously demonstrated that the chronic consumption of a high-fat diet (HFD) promotes lung and liver metastases of 4T1 mammary carcinoma cells in obesity-resistant BALB/c mice. To examine early transcriptional responses to tumour progression in the liver and lungs of HFD-fed mice, 4-week-old female BALB/c mice were divided into four groups: sham-injected, control diet (CD)-fed; sham-injected, HFD-fed (SH); 4T1 cell-injected, CD-fed (TC); 4T1 cell-injected, HFD-fed (TH). Following 16 weeks of either a CD or HFD, 4T1 cells were injected into the mammary fat pads of mice in the TC and TH groups and all mice were continuously fed identical diets. At 14 d post-injection, RNA was isolated from hepatic and pulmonary tissues for microarray analysis of mRNA expression. Functional annotation and core network analyses were conducted for the TH/SH Unique gene set. Inflammation in hepatic tissues and cell mitosis in pulmonary tissues were the most significant biological functions in the TH/SH Unique gene set. The biological core networks of the hepatic TH/SH Unique gene set were characterised as those genes involved in the activation of acute inflammatory responses (Orm1, Lbp, Hp and Cfb), disordered lipid metabolism and deregulated cell cycle progression. Networks of the pulmonary Unique gene set displayed the deregulation of cell cycle progression (Cdc20, Cdk1 and Bub1b). These HFD-influenced alterations may have led to favourable conditions for the formation of both pro-inflammatory and pro-mitotic microenvironments in the target organs that promote immune cell infiltration and differentiation, as well as the infiltration and proliferation of metastatic tumour cells.

3,3'-Diindolylmethane alleviates oxazolone-induced colitis through Th2/Th17 suppression and Treg induction

The T cell is pivotal in orchestrating and promoting an immune response during ulcerative colitis (UC). The aryl hydrocarbon receptor (AhR) is involved in the regulation of T cell responses, and 3,3'-diindolylmethane (DIM) is a known ligand of AhR. The aim of this study was to examine the therapeutic effects of DIM in experimental colitis and to investigate the possible mechanisms underlying its effects on mucosal T cell responses. The therapeutic effects of DIM were studied in an oxazolone-induced colitis model. The pathologic markers of colitis were measured, moreover, T-helper cell (Th)- and regulatory T cell (Treg)-related transcription factor expression and associated colonic cytokine production were determined. The impact of DIM on T cell differentiation was further investigated in cultures of naive Th cells that were stimulated with anti-CD3/CD28 monoclonal antibodies (mAbs). The administration of DIM attenuated experimental colitis, as determined by pathological indices. DIM may affect signaling pathways downstream of AhR, leading to decreased Th2/Th17 cells and increased Tregs. Ultimately, this could result in the alleviation of experimental colitis. DIM has shown anti-UC activity in animal models via inhibition of Th2/Th17 cells and promotion of Tregs and may thus offer potential treatments for UC patients.

Suppression of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation in mice by transduced Tat-Annexin protein

We examined that the protective effects of ANX1 on 12-O-tetradecanoylphorbol- 13-acetate (TPA)-induced skin inflammation in animal models using a Tat-ANX1 protein. Topical application of the Tat-ANX1 protein markedly inhibited TPAinduced ear edema and expression levels of cyclooxygenase-2 (COX-2) as well as pro-inflammatory cytokines such as interleukin- 1 beta (IL-1 β), IL-6, and tumor necrosis factor-alpha (TNF-α). Also, application of Tat-ANX1 protein significantly inhibited nuclear translocation of nuclear factor-kappa B (NF-κ B) and phosphorylation of p38 and extracellular signalregulated kinase (ERK) mitogen-activated protein kinase (MAPK) in TPA-treated mice ears. The results indicate that Tat-ANX1 protein inhibits the inflammatory response by blocking NF-κ B and MAPK activation in TPA-induced mice ears. Therefore, the Tat-ANX1 protein may be useful as a therapeutic agent against inflammatory skin diseases.

INDOLE-3-CARBINOL EXERTS SEX-SPECIFIC EFFECTS IN MURINE COLITIS

Due to the severe adverse effects that can accompany conventional therapies for Crohn's disease, the search for natural complementary therapies has increased dramatically in recent years. Indole-3-carbinol (I3C), a constituent of cruciferous vegetables, possesses anti-inflammatory properties; however, its effects on intestinal inflammation have yet to be evaluated. To test the hypothesis that I3C dampens intestinal inflammation, C57Bl/6 mice were treated with I3C and exposed to 2,4,6-trinitrobenzenesulfonic acid (TNBS) to induce colitis. Several parameters of disease severity and inflammation were subsequently evaluated. I3C dampened the disease severity, as indicated by decreased body weight loss and decreased severity of clinical signs. Interestingly, this effect was observed in female but not male mice, which displayed a trend towards exacerbated colitis. Differential effects were observed in the profiles of cytokine production, as the production of pro-inflammatory cytokines was increased in males. The sex-specific effect of I3C in TNBS-induced colitis is a novel finding and warrants further investigation since this is a common dietary compound and is also available commercially.

Bone marrow-derived, alternatively activated macrophages enhance solid tumor growth and lung metastasis of mammary carcinoma cells in a Balb/C mouse orthotopic model

INTRODUCTION

Tumor-associated macrophages, which are derived from the infiltration of circulating bone marrow-derived monocytes, consist primarily of a polarized M2 macrophage (M2-Mϕ) population and are associated with poor prognosis in various cancers. In the present study, we attempted to assess whether M2-Mϕs derived from bone marrow stimulate the promotion and progression of mammary tumors.

METHODS

4T1 murine mammary carcinoma cells were injected either alone or coupled with M2-Mϕs into the mammary fat pads of syngeneic female Balb/C mice. M2-Mϕs were prepared by treating monocytes isolated from female Balb/C mouse bone marrow with IL-4. Tumor cell growth was determined using an in vivo imaging system and the expression of cell proliferation-related, angiogenesis-related, and lymphangiogenesis-related proteins in tumor tissues was immunohistochemically analyzed. To evaluate the effects of the crosstalk between 4T1 cells and M2-Mϕs on the secretion and mRNA expression of cytokines and the migration of monocytes, 4T1 cells and M2-Mϕs were co-cultured and cytokine antibody array, real-time RT-PCR, and trans-well migration assays were conducted.

RESULTS

The co-injection of M2-Mϕs into the mammary fat pads of mice increased solid tumor growth and lung metastasis of 4T1 cells as well as the infiltration of CD45+ leukocytes into tumor tissues. The proportions of Ki-67+ proliferating cells and the expression of hypoxia inducible factor-1α, vascular endothelial cell growth factor A, CD31, vascular endothelial cell growth factor C, and lymphatic vessel endothelial receptor-1 were increased significantly in the tumor tissues of mice co-injected with 4T1 cells and M2-Mϕs. The in vitro results revealed that the proliferation of 4T1 cells, the migration of monocytes, and the secretion of granulocyte colony-stimulating factor, IFNγ, IL-1α, IL-2, IL-16, IFNγ-induced protein-10, keratinocyte-derived chemokine, macrophage colony-stimulating factor, monocyte chemotactic protein-1, macrophage inflammatory protein-1α, and RANTES were increased when 4T1 cells were co-cultured with M2-Mϕs, as compared with when the 4T1 cells were cultured alone.

CONCLUSION

The crosstalk between 4T1 cells and M2-Mϕs increased the production of cytokines, which may have induced immune cell infiltration into tumor tissues, tumor cell proliferation, angiogenesis, and lymph angiogenesis, thereby increasing solid tumor growth and lung metastasis.

Luteolin decreases IGF-II production and downregulates insulin-like growth factor-I receptor signaling in HT-29 human colon cancer cells

Background

Luteolin is a 3',4',5,7-tetrahydroxyflavone found in various fruits and vegetables. We have shown previously that luteolin reduces HT-29 cell growth by inducing apoptosis and cell cycle arrest. The objective of this study was to examine whether luteolin downregulates the insulin-like growth factor-I receptor (IGF-IR) signaling pathway in HT-29 cells.

Methods

In order to assess the effects of luteolin and/or IGF-I on the IGF-IR signaling pathway, cells were cultured with or without 60 μmol/L luteolin and/or 10 nmol/L IGF-I. Cell proliferation, DNA synthesis, and IGF-IR mRNA levels were evaluated by a cell viability assay, [³H]thymidine incorporation assays, and real-time polymerase chain reaction, respectively. Western blot analyses, immunoprecipitation, and in vitro kinase assays were conducted to evaluate the secretion of IGF-II, the protein expression and activation of IGF-IR, and the association of the p85 subunit of phophatidylinositol-3 kinase (PI3K) with IGF-IR, the phosphorylation of Akt and extracellular signal-regulated kinase (ERK)1/2, and cell division cycle 25c (CDC25c), and PI3K activity.

Results

Luteolin (0 - 60 μmol/L) dose-dependently reduced the IGF-II secretion of HT-29 cells. IGF-I stimulated HT-29 cell growth but did not abrogate luteolin-induced growth inhibition. Luteolin reduced the levels of the IGF-IR precursor protein and IGF-IR transcripts. Luteolin reduced the IGF-I-induced tyrosine phosphorylation of IGF-IR and the association of p85 with IGF-IR. Additionally, luteolin inhibited the activity of PI3K activity as well as the phosphorylation of Akt, ERK1/2, and CDC25c in the presence and absence of IGF-I stimulation.

Conclusions

The present results demonstrate that luteolin downregulates the activation of the PI3K/Akt and ERK1/2 pathways via a reduction in IGF-IR signaling in HT-29 cells; this may be one of the mechanisms responsible for the observed luteolin-induced apoptosis and cell cycle arrest.

Benzyl isothiocyanate inhibits basal and hepatocyte growth factor-stimulated migration of breast cancer cells

Benzyl isothiocyanate (BITC), which is found in cruciferous vegetables, has been shown to have anti-carcinogenic properties. Hepatocyte growth factor (HGF) has the ability to stimulate dissociation, migration, and invasion in various tumor cells, and abnormally increased expressions of HGF and its transmembrane tyrosine kinase receptor, c-Met, have previously been detected in human breast cancer, and are associated with high tumor grade and poor prognosis. In this study, in order to assess the mechanisms relevant to the BITC-induced regulation of breast cancer cell migration and invasion, MDA-MB-231 human breast cancer cells and 4T1 murine mammary carcinoma cells were cultured in the presence of 0-4 μmol/l BITC with or without 10 μg/l of HGF. BITC inhibited both the basal and HGF-induced migration of MDA-MB-231 and 4T1 cells in a dose-dependent manner. In MDA-MB-231 cells, BITC reduced both basal and HGF-induced secretion and activity of urokinase-type plasminogen activator (uPA). In addition, BITC increased the protein levels of plasminogen activator inhibitor-1. HGF stimulated c-Met and Akt phosphorylation, but did not affect the phosphorylation of extracellular signal-regulated kinase-1/2 or stress-activated protein/c-jun N-terminal kinase. BITC suppressed NF-κB activity and reduced the HGF-induced phosphorylation of c-Met and Akt in a dose-dependent manner. LY294002, a specific Akt inhibitor, reduced both basal and HGF-induced uPA secretion and migration of MDA-MB-231 cells. In this study, we demonstrated that BITC profoundly inhibits the migration and invasion of MDA-MB-231 cells, which is associated with reduced uPA activity, and also that these phenomena are accompanied by the suppression of Akt signaling.

Anti-inflammatory activity of edible oyster mushroom is mediated through the inhibition of NF-κB and AP-1 signaling

Background

Mushrooms are well recognized for their culinary properties as well as for their potency to enhance immune response. In the present study, we evaluated anti-inflammatory properties of an edible oyster mushroom (Pleurotus ostreatus) in vitro and in vivo.

Methods

RAW264.7 murine macrophage cell line and murine splenocytes were incubated with the oyster mushroom concentrate (OMC, 0-100 μg/ml) in the absence or presence of lipopolysacharide (LPS) or concanavalin A (ConA), respectively. Cell proliferation was determined by MTT assay. Expression of cytokines and proteins was measured by ELISA assay and Western blot analysis, respectively. DNA-binding activity was assayed by the gel-shift analysis. Inflammation in mice was induced by intraperitoneal injection of LPS.

Results

OMC suppressed LPS-induced secretion of tumor necrosis factor-α (TNF-α, interleukin-6 (IL-6), and IL-12p40 from RAW264.7 macrophages. OMC inhibited LPS-induced production of prostaglandin E2 (PGE₂) and nitric oxide (NO) through the down-regulation of expression of COX-2 and iNOS, respectively. OMC also inhibited LPS-dependent DNA-binding activity of AP-1 and NF-κB in RAW264.7 cells. Oral administration of OMC markedly suppressed secretion of TNF-α and IL-6 in mice challenged with LPS in vivo. Anti-inflammatory activity of OMC was confirmed by the inhibition of proliferation and secretion of interferon-γ (IFN-γ), IL-2, and IL-6 from concanavalin A (ConA)-stimulated mouse splenocytes.

Conclusions

Our study suggests that oyster mushroom possesses anti-inflammatory activities and could be considered a dietary agent against inflammation. The health benefits of the oyster mushroom warrant further clinical studies.

Effect of diindolylmethane on Ca(2+) movement and viability in HA59T human hepatoma cells

The effect of diindolylmethane, a natural compound derived from indole-3-carbinol in cruciferous vegetables, on cytosolic Ca(2+) concentrations ([Ca(2+)](i)) and viability in HA59T human hepatoma cells is unclear. This study explored whether diindolylmethane changed [Ca(2+)](i) in HA59T cells. The Ca(2+)-sensitive fluorescent dye fura-2 was applied to measure [Ca(2+)](i). Diindolylmethane at concentrations of 1-50 μM evoked a [Ca(2+)](i) rise in a concentration-dependent manner. The signal was reduced by removing Ca(2+). Diindolylmethane-induced Ca(2+) influx was not inhibited by nifedipine, econazole, SK&F96365, and protein kinase C modulators but was inhibited by aristolochic acid. In Ca(2+)-free medium, treatment with the endoplasmic reticulum Ca(2+) pump inhibitors thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ) inhibited or abolished diindolylmethane-induced [Ca(2+)](i) rise. Incubation with diindolylmethane inhibited thapsigargin or BHQ-induced [Ca(2+)](i) rise. Inhibition of phospholipase C with U73122 reduced diindolylmethane-induced [Ca(2+)](i) rise. At concentrations of 10-75 μM, diindolylmethane killed cells in a concentration-dependent manner. The cytotoxic effect of diindolylmethane was not reversed by chelating cytosolic Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. Propidium iodide staining data suggest that diindolylmethane (25-50 μM) induced apoptosis in a concentration-dependent manner. Collectively, in HA59T cells, diindolylmethane induced a [Ca(2+)](i) rise by causing phospholipase C-dependent Ca(2+) release from the endoplasmic reticulum and Ca(2+) influx via phospholipase A(2)-sensitive channels. Diindolylmethane induced cell death that may involve apoptosis.

Phenethyl isothiocyanate inhibits 12-O-tetradecanoylphorbol-13-acetate-induced inflammatory responses in mouse skin

Phenethyl isothiocyanate (PITC) is the hydrolysis product of the glucosinolate gluconasturtiin in cruciferous vegetables. This study was conducted to determine whether PITC inhibits 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation in the mouse ear. Topical application of 5 nmol of TPA to mouse ears markedly increased the ear weight, expression of the inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 protein, and phosphorylation of the inhibitor of κB (IκB) α, AKT, and extracellular signal-regulated protein kinase (ERK) 1/2 and reduced IκBα protein levels. Pretreatment with PITC (150-450 nmol) significantly suppressed these TPA-induced inflammatory responses. We also determined whether low concentrations of PITC (0.5-5 μmol/L) inhibited lipopolysaccharide (LPS)-stimulated inflammatory responses in Raw264.7 cells. PITC dose-dependently reduced the LPS-induced secretion of nitric oxide, prostaglandin E(2), interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, as well as COX-2 and iNOS protein expression. PITC also attenuated LPS-induced increases in iNOS, COX-2, IL- 6, IL-1β, and TNF-α mRNA levels, as well as the promoter-dependent transcriptional activation of the genes for iNOS and COX-2. PITC inhibited LPS-induced IκBα phosphorylation and degradation and subsequently reduced LPS-induced p65 nuclear translocation and the transcriptional activity of nuclear factor-κB (NF-κB), which was accompanied by a reduction in ERK1/2 and AKT phosphorylation. The results of this study demonstrated that PITC effectively inhibits inflammatory responses in vivo and in vitro, which may be mediated via the inhibition of AKT and ERK1/2 activation, leading to subsequent inhibition of the transcriptional activity of NF-κB.

Inflammatory signaling in skeletal muscle insulin resistance: green signal for nutritional intervention?

PURPOSE OF REVIEW

To review the evidence implying a role of inflammatory signaling pathways, specifically nuclear factor-κB and c-Jun NH2-terminal kinase, in fatty acid-induced skeletal muscle insulin resistance and to discuss the potential of dietary interventions to interfere with these processes.

RECENT FINDINGS

Fatty acids can induce skeletal muscle insulin resistance via inflammatory signaling after binding Toll-like receptors at the cell membrane of muscle cells or after accumulating as intramyocellular lipid metabolites. In both processes, activation of intracellular inflammatory signaling is involved. The majority of literature addressing the causality of muscle nuclear factor-κB activation in skeletal muscle insulin resistance suggests that insulin resistance does not require muscle nuclear factor-κB activation. Recently, strong evidence was given that c-Jun NH2-terminal kinase signaling is an important inflammatory pathway involved in skeletal muscle insulin resistance. Furthermore, it is well established that proinflammatory cytokines originating from the enlarged adipose tissue or from activated adipose tissue macrophages can cause muscle insulin resistance. Recently, also macrophages resided in the muscle have been proposed to play an important role in muscle insulin resistance. Because of their anti-inflammatory characteristics, several dietary components like polyphenols may be interesting candidates for manipulating skeletal muscle insulin resistance.

SUMMARY

Several dietary components, like polyphenols, have been reported to interfere with inflammatory signaling. To test whether these compounds can be used to prevent or reverse insulin resistance, well controlled human intervention studies have to be designed.

Xanthones from mangosteen inhibit inflammation in human macrophages and in human adipocytes exposed to macrophage-conditioned media

Obesity-associated inflammation is characterized by recruitment of macrophages (MPhi) into white adipose tissue (WAT) and production of inflammatory cytokines, leading to the development of insulin resistance. The xanthones, alpha- and gamma-mangostin (MG), are major bioactive compounds found in mangosteen that are reported to have antiinflammatory and antioxidant properties. Thus, we examined the efficacy of MG to prevent lipopolysaccharide (LPS)-mediated inflammation in human MPhi (differentiated U937 cells) and cross-talk with primary cultures of newly differentiated human adipocytes. We found that alpha- and gamma-MG attenuated LPS-induced expression of inflammatory genes, including tumor necrosis factor-alpha, interleukin-6, and interferon gamma-inducible protein-10 in a dose-dependent manner in MPhi. We also found that alpha- and gamma-MG attenuated LPS-activated mitogen-activated protein kinases (MAPK) and activator protein (AP)-1, but only gamma-MG reduced nuclear factor-kappaB (NF-kappaB). In addition, alpha- and gamma-MG attenuated LPS suppression of PPARgamma gene expression in a dose-dependent manner. Notably, the ability of MPhi-conditioned media to cause inflammation and insulin resistance in primary cultures of human adipocytes was attenuated by pretreating MPhi with gamma-MG. Taken together, these data demonstrate that MG attenuates LPS-mediated inflammation in MPhi and insulin resistance in adipocytes, possibly by preventing the activation of MAPK, NF-kappaB, and AP-1, which are central to inflammatory cytokine production in WAT.

Tetrahydroabietic Acid, a Reduced Abietic Acid, Inhibits the Production of Inflammatory Mediators in RAW264.7 Macrophages Activated with Lipopolysaccharide

Abietic acid (AA), the main component of the rosin fraction of oleoresin synthesized by conifer species, has been reported to have anti-inflammatory effects. AA is a weak contact allergen; however, compounds resulting from its oxidation by air elicit stronger allergic response. Hydrogenation of the conjugated double bonds of AA, as in tetrahydroabietic acid (THAA), decreases its susceptibility to air oxidation and would thus reduce the allergenicity of AA. The aim of this study was to investigate whether THAA could exert anti-inflammatory effects to the same extent as AA in RAW264.7 macrophages activated with the endotoxin lipopolysaccharide (LPS). THAA and AA inhibited the production of nitric oxide (NO) and prostaglandin E₂ by suppressing the expression of inducible NO synthase and cyclooxygenase-2, respectively, in LPS-activated RAW264.7 macrophages. They also inhibited the LPS-induced production of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α. Both THAA and AA prevented the LPS-induced nuclear translocation of the nuclear factor-κB/p65 subunit, suggesting that THAA may inhibit the production of pro-inflammatory mediators through the same mechanism as AA. In comparison, the anti-inflammatory effects of THAA and AA were almost identical, indicating that THAA retains the anti-inflammatory activity of AA at least in LPS-activated RAW264.7 macrophages.

Oral administration of 3,3'-diindolylmethane inhibits lung metastasis of 4T1 murine mammary carcinoma cells in BALB/c mice

3,3'-diindolylmethane (DIM) is the major in vivo product of the acid-catalyzed oligomerization of indole-3-carbinol present in cruciferous vegetables, and it has been shown to exhibit anticancer properties. In this study, we assessed the effects of DIM on the metastasis of 4T1 mouse mammary carcinoma cells. In vitro culture studies showed that DIM dose-dependently inhibited the migration, invasion, and adhesion of 4T1 cells at concentrations of 0-10 micromol/L without attendant changes in cell viability. In an in vivo lung metastasis model, 4T1 cells (2 x 10(5) cells/mouse) were injected into the tail veins of syngeneic female BALB/c mice. Beginning on the second day, the mice were subjected to gavage with 0-10 mg DIM/(kg body weight x d) for 13 d. Oral DIM administration resulted in a marked reduction in the number of pulmonary tumor nodules. DIM treatment significantly reduced the levels of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, and vascular cell adhesion molecule (VCAM)-1 and increased TIMP-2 levels in the sera and lungs of mice injected with 4T1 cells. Additionally, DIM treatment reduced the serum concentrations of interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNF)alpha. We have demonstrated that DIM profoundly inhibits the lung metastasis of 4T1 cells, which was accompanied by reduced levels of MMP, adhesion molecules, and proinflammatory cytokines. These results indicate that DIM has potential as an antimetastatic agent for the treatment of breast cancer.

Rosmarinic acid in Prunella vulgaris ethanol extract inhibits lipopolysaccharide-induced prostaglandin E2 and nitric oxide in RAW 264.7 mouse macrophages

Prunella vulgaris has been used therapeutically for inflammation-related conditions for centuries, but systematic studies of its anti-inflammatory activity are lacking and no specific active components have been identified. In this study, water and ethanol extracts of four P. vulgaris accessions were applied to RAW 264.7 mouse macrophages, and the ethanol extracts significantly inhibited lipopolysaccharide (LPS)-stimulated prostaglandin E2 (PGE2) and nitric oxide (NO) production at 30 microg/mL without affecting cell viability. Extracts from different accessions of P. vulgaris were screened for anti-inflammatory activity to identify accessions with the greatest activity. The inhibition of PGE2 and NO production by selected extracts was dose-dependent, with significant effects seen at concentrations as low as 10 microg/mL. Fractionation of ethanol extracts from the active accession, Ames 27664, suggested fractions 3 and 5 as possible major contributors to the overall activity. Rosmarinic acid (RA) content in P. vulgaris was found to independently inhibit inflammatory response, but it only partially explained the extracts' activity. LPS-induced cyclooxygenase-2 (COX-2) and nitric oxide synthase (iNOS) protein expression were both attenuated by P. vulgaris ethanol extracts, whereas RA inhibited only COX-2 expression.

3,3'-Diindolylmethane attenuates experimental arthritis and osteoclastogenesis

3,3'-Diindolylmethane (DIM) is a natural compound formed during the autolysis of glucobrassicin present in Brassica food plants. This study aimed to investigate the therapeutic efficacies of DIM on experimental arthritis. The effects of DIM on experimental arthritis were examined on a rat model of adjuvant-induced arthritis (AIA), with daily AIA paw swelling observation and histological/radiographic analysis. To elucidate the possible mechanisms of its action, serum cytokine levels as well as the expression of receptor activator for nuclear factor kappa B ligand (RANKL) in infected tissues were subsequently analyzed. The impact of DIM on osteoclastogenesis was further investigated on a mouse model of endotoxin-induced bone resorption (EIBR) and in vitro cultures of fibroblast-like cells and osteoblasts, with RANKL expression being evaluated with great interest. The administration of DIM was demonstrated to attenuate AIA in animal models, as judged by clinical and histologic indices of inflammation and tissue damage. On the one hand, DIM could reduce the expression of several inflammatory cytokines, which was, however, not adequate to prevent the development of the arthritis. On the other hand, DIM was shown to effectively inhibit the expression of RANKL, leading to the blockade of osteoclastogenesis and consequently an alleviation of experimental arthritis. Further in vitro and in vivo studies confirmed the inhibition of RANKL by DIM. DIM has shown anti-arthritis activity in animal models via inhibiting the expression of RANKL, and thus may offer potential treatments for arthritis and associated disorders.

3,3'-diindolylmethane attenuates colonic inflammation and tumorigenesis in mice

BACKGROUND

3,3-Diindolylmethane (DIM) is a major in vivo product of acid-catalyzed oligomerization of indole-3-carbinol (I3C) derived from Brassica food plants. Although DIM is known as a chemopreventive and chemotherapeutic phytochemical, the effects of DIM on inflammation in vivo are still unknown. In the present study we investigated the antiinflammatory effects of DIM on experimental colitis and colitis-associated colorectal carcinogenesis.

METHODS

To determine if DIM has an antiinflammatory effect in vivo, we examined the therapeutic effects of DIM in dextran sodium sulfate (DSS)-induced experimental colitis and colitis-associated colon carcinogenesis induced by azoxymethane (AOM)/DSS in BALB/c mice.

RESULTS

Treatment with DIM significantly attenuated loss of body weight, shortening of the colon, and severe clinical signs in a colitis model. This was associated with a remarkable amelioration of the disruption of the colonic architecture and a significant reduction in colonic myeloperoxidase activity and production of prostaglandin E(2), nitric oxide, and proinflammatory cytokines. Further, DIM administration dramatically decreased the number of colon tumors in AOM/DSS mice.

CONCLUSIONS

These results suggest that DIM-mediated antiinflammatory action at colorectal sites may be therapeutic in the setting of inflammatory bowel disease and colitis-associated colon cancer.

A novel flow cytometric high throughput assay for a systematic study on molecular mechanisms underlying T cell receptor-mediated integrin activation

Lymphocyte function-associated antigen 1 (LFA-1), a member of β2-integrin family, exerts multiple roles in host T cell immunity and has been identified as a useful drug-development target for inflammatory and autoimmune diseases. Applying the findings that primary resting T cells absorb nanometric membrane vesicles derived from antigen presenting cells (APC) via dual receptor/ligand interactions of T cell receptor (TCR) with cognate peptide-major histocompatibility complex (MHC) complex (pMHC) and LFA-1 with its ligand, intercellular adhesion molecule-1 (ICAM-1), and that signaling cascades triggered by TCR/pMHC interaction take a part in the vesicle-absorption, we established a cell-based high throughput assay for systematic investigation, via isolation of small molecules modulating the level of vesicle-absorption, of molecular mechanisms underlying the T cell absorption of APC-derived vesicles, i.e., structural basis of TCR/pMHC and LFA-1/ICAM-1 interactions and TCR-mediated LFA-1 activation. As primary T cells along with physiological ligands expressed in biological membrane are used and also individual cells in assay samples are analyzed by flow cytometry, results obtained using the assay system hold superior physiological and therapeutic relevance as well as statistical precision.

Lipid G protein-coupled receptor ligand identification using beta-arrestin PathHunter assay

A growing number of orphan G-protein-coupled receptors (GPCRs) have been reported to be activated by lipid ligands, such as lysophosphatidic acid, sphingosine 1-phosphate (S1P), and cannabinoids, for which there are already well established receptors. These new ligand claims are controversial due to either lack of independent confirmations or conflicting reports. We used the beta-arrestin PathHunter assay system, a newly developed, generic GPCR assay format that measures beta-arrestin binding to GPCRs, to evaluate lipid receptor and ligand pairing. This assay eliminates interference from endogenous receptors on the parental cells because it measures a signal that is specifically generated by the tagged receptor and is immediately downstream of receptor activation. We screened a large number of newly "deorphaned" receptors (GPR23, GPR92, GPR55, G2A, GPR18, GPR3, GPR6, GPR12, and GPR63) and control receptors against a collection of approximately 400 lipid molecules to try to identify the receptor ligand in an unbiased fashion. GPR92 was confirmed to be a lysophosphatidic acid receptor with weaker responses to farnesyl pyrophosphate and geranylgeranyl diphosphate. The putative cannabinoid receptor GPR55 responded strongly to AM251, rimonabant, and lysophosphatidylinositol but only very weakly to endocannabinoids. G2A receptor was confirmed to be an oxidized free fatty acid receptor. In addition, we discovered that 3,3'-diindolylmethane, a dietary molecule from cruciferous vegetables, which has known anti-cancer properties, to be a CB(2) receptor partial agonist, with binding affinity around 1 microm. The anti-inflammatory effect of 3,3'-diindolylmethane in RAW264.7 cells was shown to be partially mediated by CB(2).

NF-kappaB signaling pathway and its therapeutic implications in human diseases

The nuclear factor-kappaB (NF-kappaB) pathway is one of the most important cellular signal transduction pathways involved in both physiologic processes and disease conditions. It plays important roles in the control of immune function, inflammation, stress response, differentiation, apoptosis, and cell survival. Moreover, NF-kappaB is critically involved in the processes of development and progression of cancers. More importantly, recent studies have shown that NF-kappaB signaling also plays critical roles in the epithelial-mesenchymal transition (EMT) and cancer stem cells. Therefore, targeting of NF-kappaB signaling pathway could be a potent strategy for the prevention and/or treatment of human cancers and inflammatory diseases.

Cruciferous vegetable intake and the risk of human cancer: epidemiological evidence

Over several decades a number of epidemiological studies have identified the inverse associations between cruciferous vegetables and the risk of several cancers, including gastric, breast, colo-rectal, lung, prostate, bladder and endometrial cancers, via plausible physiological mechanisms. Although retrospective case–control studies have consistently reported inverse associations between the risk of these cancers and the intake of cruciferous vegetables and isothiocyanate-containing plants, current prospective cohort studies have found these associations to be weaker and less consistent. Genetic variations affecting the metabolism of glucosinolate hydrolysis products may modulate the effects of cruciferous vegetable consumption on cancer risk, which may be one of the reasons for the discrepancies between retrospective and prospective studies. In addition, methodological issues such as measurement errors of dietary exposure, misclassification, recall bias, publication bias, confounding and study design should be carefully considered in interpreting the results of case–control and cohort studies and in drawing conclusions in relation to the potential effects of cruciferous vegetables on cancers. Although recent comprehensive reviews of numerous studies have purported to show the specific protective role of cruciferous vegetables, and particularly Brassicas, against cancer risk, the current epidemiological evidence suggests that cruciferous vegetable consumption may reduce the risk only of gastric and lung cancers. However, there is at present no conclusive evidence that the consumption of cruciferous vegetables attenuates the risk of all other cancers.