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Interleukin (IL)-32, mainly produced by T-lymphocytes, natural killer cells, epithelial cells, and blood monocytes, is dominantly known as a pro-inflammatory cytokine. However, the role of IL-32 on inflammatory disease has been doubtful according to diverse conflicting results. This study was designed to examine the role of IL-32β on the development of collagen antibody (CAIA) and lipopolysaccharide (LPS)-induced inflammatory arthritis. Our data showed that the paw swelling volume and clinical score were significantly reduced in the CAIA and LPS-treated IL-32β transgenic mice compared with non-transgenic mice. The populations of cytotoxic T, NK and dendritic cells was inhibited and NF-κB and STAT3 activities were significantly lowered in the CAIA and LPS-treated IL-32β transgenic mice. The expression of pro-inflammatory proteins was prevented in the paw tissues of CAIA and LPS-treated IL-32β transgenic mice. In addition, IL-32β altered several cytokine levels in the blood, spleen and paw joint. Our data indicates that IL-32β comprehensively inhibits the inflammation responses in the CAIA and LPS-induced inflammatory arthritis model.

Activation of nuclear factor kappa-B (NF-κB) is implicated in drug resistant of lung cancer cells. Our previous data showed that thiacremonone inhibited activation of NF-κB. In the present study, we investigated whether thiacremonone enhanced susceptibility of lung cancer cells to a common anti-cancer drug paclitaxel by further inhibition of NF-κB. Thus, we used the threefold lower doses of IC50 values (50 μg/ml thiacremonone and 2.5 nM paclitaxel). We found that combination treatment with thiacremonone and paclitaxel was more susceptible (combination index; 0.40 in NCI-H460 cells and 0.46 in A549 cells) in cell growth inhibition of two types of lung cancer cell lines compared to a single agent treatment. Consistent with the combination effect on cancer cell growth inhibition, the combination treatment further induced apoptotic cell death and arrested the cancer cells in G2/M phase accompanied with a much lower expression of cdc2 and cyclin B1, and inhibited colony formation. Much more inactivation of NF-κB and greater expression of NF-κB target apoptosis regulated genes such as caspase-8 and PARPs were found by the combination treatment. Molecular model and pull down assay as well as MALDI-TOF analysis demonstrated that thiacremonone directly binds to p50. These data indicated that thiacremonone leads to increased apoptotic cell death in lung cancer cell lines through greater inhibition of NF-κB by the combination treatment with paclitaxel.

Overdose of acetaminophen (APAP) causes necrosis of centrilobular cells of the liver. Accumulating evidence suggests that innate immune system may contribute to APAP-induced hepatotoxicity. Interaction between RANTES and its receptor C-C chemokine receptor (CCR) 5 is related to recruitment of macrophages to sites of inflammation. In this study, we examined effects of CCR5 deficiency on APAP-mediated liver injury by employing CCR5 knockout (KO) mice. CCR5 wild-type (WT) and KO mice received intraperitoneal injection of APAP (300 mg/kg) and were killed 24 h after the injection. Hepatic injury was determined by using histological and biochemical analyses. Intraperitoneal APAP caused the hepatocytic necrosis, as evidenced by hematoxylin and eosin staining and an increase in alanine transaminase and aspartate transaminase levels in serum. Hepatic damage appeared to be larger in CCR5 WT animals compared with KO animals. There were no differences in cytochrome P450 2E1 between CCR5 WT and KO animals suggesting that the resistance of CCR5 KO mice did not come from alterations in APAP metabolism. Infiltration of macrophages into the liver was reduced in CCR5 KO mice, and this was accompanied decreased inflammatory responses. Inhibition of macrophage activity by pretreatment of gadolinium chloride significantly blocked APAP-caused hepatotoxicity. These results indicate that recruitment of macrophage into the inflammatory sites significantly contributes to APAP-mediated hepatocytic death and CCR5 gene deletion protects from APAP-induced liver injury by alleviating macrophage recruitment and inflammatory responses. This study represents a critical role of CCR5 in macrophage infiltration into the liver and subsequent hepatotoxicity upon challenge of APAP.

The purpose of this study was to evaluate the anticancer efficacy of cetuximab combined with cisplatin (combination treatment) on colon cancer growth, as well as its underlying action mechanism. Combination treatment synergistically potentiated the effect of cetuximab on cell growth inhibition and apoptosis induction in HCT116 and SW480 cells. Combination treatment further suppressed the expression of the activated form of epidermal growth factor receptor (EGFR) and MAP kinase (p-ERK and p-p38) and also significantly inhibited the activity of activator protein-1 (AP-1) and nuclear factor kappa B (NF-κB). Additionally, the expression of cyclooxygenase-2 (COX-2) and interleukin-8 (IL-8) mRNA was significantly reduced by the combination treatment as compared to the expression seen for treatment with cetuximab or cisplatin alone. We found that the synergistic inhibitory effects of cetuximab and cisplatin on AP-1 and NF-κB activation, as well as on cell viability, were reversed by pretreatment with an ERK inhibitor. Results demonstrate that combined treatment with cetuximab and cisplatin exerts synergistic anticancer effects on colon cancer cells and also suggest that the ERK pathway plays a critical role in these effects via the suppression of the EGFR signaling pathway, along with the inhibition of COX-2, IL-8, and AP-1 and NF-κB.

Background and Purpose: Products of Maillard reactions between aminoacids and reducing sugars are known to have anti-inflammatory properties. Here we have assessed the anti-arthritis effects of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal and its possible mechanisms of action., Experimental Approach: We used cultures of LPS-activated macrophages (RAW264.7 cells) and human synoviocytes from patients with rheumatoid arthritis for in vitro assays and the collagen-induced arthritis model in mice. NO generation, iNOS and COX2 expression, and NF-κB/IKK and STAT3 activities were measured in vitro and in joint tissues of arthritic mice, along with clinical scores and histopathological assessments. Binding of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal to STAT3 was evaluated by a pull-down assay and its binding site was predicted using molecular docking studies with Autodock VINA., Key Results: (E)-2,4-bis(p-hydroxyphenyl)-2-butenal (2.5-10 μg·mL(-1) ) inhibited LPS-inducedNO generation, iNOS and COX2 expression, and NF-κB/IKK and STAT3 activities in macrophage and human synoviocytes. This compound also suppressedcollagen-induced arthritic responses in mice by inhibiting expression of iNOS and COX2, and NF-κB/IKK and STAT3 activities; it also reduced bone destruction and fibrosis in joint tissues. A pull-down assay showed that (E)-2,4-bis(p-hydroxyphenyl)-2-butenal interfered with binding of ATP to STAT3. Docking studies suggested that (E)-2,4-bis(p-hydroxyphenyl)-2-butenal bound to the DNA-binding interface of STAT3 possibly inhibiting ATP binding to STAT3 in an allosteric manner., Conclusions and Implications: (E)-2,4-bis(p-hydroxyphenyl)-2-butenal exerted anti-inflammatory and anti-arthritic effects through inhibition of the NF-κB/STAT3 pathway by direct binding to STAT3. This compound could be a useful agent for the treatment of arthritic disease., (© 2014 The British Pharmacological Society.)

The medicinal properties of functionally active organosulfur compounds such as allin, diallyl disulfide, S-allylmercaptocysteine, and S-trityl-L-cysteine isolated from garlic have received great attention from a large number of investigators who have studied their pharmacological effects for the treatment of various diseases. These organosulfur compounds are able to prevent for development of cancer, cardiovascular, neurological, and liver diseases as well as allergy and arthritis. There have been also many reports on toxicities and pharmacokinetics of these compounds. The aim of this study is to review a variety of experimental and clinical reports, and describe the effectiveness, toxicities and pharmacokinetics, and possible mechanisms of pharmaceutical actions of functionally active compounds isolated from garlic., (Copyright © 2013 Elsevier Inc. All rights reserved.)

The Maillard reaction products are known to be effective in chemoprevention. Here, we focused on the anti-cancer effects of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal on in vitro and in vivo colon cancer. We analysed the anti-cancer activity of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal on colon cancer cells by using cell cycle and apoptosis analysis. To elucidate it's mechanism, NF-κB DNA binding activity, docking model as well as pull-down assay. Further, a xenograft model of colon cancer was studied to test the in vivo effects of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal. (E)-2,4-Bis(p-hydroxyphenyl)-2-butenal inhibited colon cancer cells (SW620 and HCT116) growth followed by induction of apoptosis in a concentration-dependent manner via down-regulation of NF-κB activity. In docking model as well as pull-down assay, (E)-2,4-bis(p-hydroxyphenyl)-2-butenal directly binds to three amino acid residues of IKKβ, thereby inhibited IKKβ activity in addition to induction of death receptor 6 (DR6) as well as their target apoptotic genes. Finally, (E)-2,4-bis(p-hydroxyphenyl)-2-butenal suppressed anchorage-independent cancer cell growth, and tumor growth in xenograft model accompanied with apoptosis through inhibition of IKKβ/NF-κB activity, and overexpression of DR6. These results suggest that (E)-2,4-bis(p-hydroxyphenyl)-2-butenal inhibits colon cancer cell growth through inhibition of IKKβ/NF-κB activity and induction of DR6 expression.

Cytokine and activation of lymphocytes are critical for tumor growth. We investigated whether interleukin (IL)-32β overexpression changes other cytokine levels and activates cytotoxic lymphocyte, and thus modify tumor growth. Herein, IL-32β inhibited B16 melanoma growth in IL-32β-overexpressing transgenic mice (IL-32β mice), and downregulated the expressions of anti-apoptotic proteins (bcl-2, IAP, and XIAP) and cell growth regulatory proteins (Ki-67 antigen (Ki-67) and proliferating cell nuclear antigen (PCNA)), but upregulated the expressions of pro-apoptotic proteins (bax, cleaved caspase-3, and cleaved caspase-9). IL-32β also inhibited colon and prostate tumor growth in athymic nude mice inoculated with IL-32β-transfected SW620 colon or PC3 prostate cancer cells. The forced expression of IL-32β also inhibited cell growth in cultured colon and prostate cancer cells, and these inhibitory effects were abolished by IL-32 small interfering RNA (siRNA). IL-10 levels were elevated, but IL-1β, IL-6, and tumor necrosis factor-alpha (TNF-α) levels were reduced in the tumor tissues and spleens of IL-32β mice, and athymic nude mice. The number of cytotoxic T (CD8(+)) and natural killer (NK) cells in tumor tissues, spleen, and blood was significantly elevated in IL-32β mice and athymic nude mice inoculated with IL-32β-transfected cancer cells. Constituted activated NF-κB and STAT3 levels were reduced in the tumor tissues of IL-32β mice and athymic nude mice, as well as in IL-32β-transfected cultured cancer cells. These findings suggest that IL-32β inhibits tumor growth by increasing cytotoxic lymphocyte numbers, and by inactivating the NF-κB and STAT3 pathways through changing of cytokine levels in tumor tissues.

High doses of acetaminophen (APAP; N-acetyl-p-aminophenol) cause severe hepatotoxicity after metabolic activation by cytochrome P450 2E1. This study was undertaken to examine the preventive effects of thiacremonone, a compound extracted from garlic, on APAP-induced acute hepatic failure in male C57BL/6J. Mice received with 500 mg/kg APAP after a 7-day pretreatment with thiacremonone (10-50 mg/kg). Thiacremonone inhibited the APAP-induced serum ALT and AST levels in a dose-dependent manner, and markedly reduced the restricted area of necrosis and inflammation by administration of APAP. Thiacremonone also inhibited the APAP-induced depletion of intracellular GSH, induction of nitric oxide, and lipid peroxidation as well as expression of P450 2E1. After APAP injection, the numbers of Kupffer cells, natural killer cells, and cytotoxic T cells were elevated, but the elevated cell numbers in the liver were reduced in thiacremonone pretreated mice. The expression levels of I-309, M-CSF, MIG, MIP-1 α , MIP-1 β , IL-7, and IL-17 were increased by APAP treatment, which were inhibited in thiacremonone pretreated mice. These data indicate that thiacremonone could be a useful agent for the treatment of drug-induced hepatic failure and that the reduction of cytotoxic immune cells as well as proinflammatory cytokine production may be critical for the prevention of APAP-induced acute liver toxicity.

Garlic extracts exert anti-cancer and anti-inflammatory effects. However, the anti-adipogenic effect of garlic-derived compounds remains unclear. In this study, we examined the effect of thiacremonone, a sulfur compound isolated from garlic, on adipocyte differentiation using 3T3-L1 cells. We found that thiacremonone significantly inhibited 3T3-L1 differentiation via down-regulation of adipogenesis-related transcription factors and adipogenic markers. The inhibitory effect mainly occurred at the early phase of differentiation in 3T3-L1 cells. There was no cytotoxic effect of thiacremonone in 3T3-L1 cells and treatment of differentiating 3T3-L1 cells with thiacremonone resulted in AMPK activation, which led to an attenuated expression of acetyl CoA carboxylase-1 (ACC-1), an essential enzyme for the synthesis and usage of fatty acids. Moreover, thiacremonone enhanced the mRNA level of carnitine palmitoyltransferase (CPT-1). The modulating effect of thiacremonone on expressions of genes involved in lipolysis was partially abrogated by treatment with compound C, an AMPK inhibitor. Taken together, these results indicated that thiacremonone-induced AMPK activation, inhibition of ACC-1 expression and concomitant recovery of CPT-1 expression resulted in the suppression of intracellular lipid droplet levels, suggesting that thiacremonone may induce reduction of lipid synthesis and increases in fatty acid oxidation partially mediated via AMPK activation. Thiacremonone may be a promising compound for the treatment of obesity., (Copyright © 2012 Elsevier Inc. All rights reserved.)

The Maillard Reaction Products (MRPs) are chemical compounds which have been known to be effective in chemoprevention. Death receptors (DR) play a central role in directing apoptosis in several cancer cells. In our previous study, we demonstrated that (E)-2,4-bis(p-hydroxyphenyl)-2-butenal, a MRP product, inhibited human colon cancer cell growth by inducing apoptosis via nuclear factor-κB (NF-κB) inactivation and G2/M phase cell cycle arrest. In this study, (E)-2,4-bis(p-hydroxyphenyl)-2-butenal diacetate, a new (E)-2,4-bis(p-hydroxyphenyl)-2-butenal derivative, was synthesized to improve their solubility and stability in water and then evaluated against NCI-H460 and A549 human lung cancer cells. (E)-2,4-bis(p-hydroxyphenyl)-2-butenal diacetate reduced the viability in both cell lines in a time and dose-dependent manner. We also found that (E)-2,4-bis(p-hydroxyphenyl)-2-butenal diacetate increased apoptotic cell death through the upregulation of the expression of death receptor (DR)-3 and DR6 in both lung cancer cell lines. In addition to this, the transfection of DR3 siRNA diminished the growth inhibitory and apoptosis inducing effect of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal diacetate on lung cancer cells, however these effects of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal diacetate was not changed by DR6 siRNA. These results indicated that (E)-2,4-bis(p-hydroxyphenyl)-2-butenal diacetate inhibits human lung cancer cell growth via increasing apoptotic cell death by upregulation of the expression of DR3.

Garlic is widely used as a spice. Garlic extracts exert anticancer and antiinflammatory effects, but its antiobesity efficacy studies have produced conflicting results. The antiobesity effects of thiacremonone, a sulfur compound isolated from garlic, was evaluated in obese db/db mice. Thiacremonone was orally administrated to mice for 3 weeks. The thiacremonone-treated db/db mice showed a loss of body weight and decrease in blood triglyceride and glucose levels compared with the control mice. Histological analysis further revealed that thiacremonone significantly decreased lipid accumulation in the fatty livers of treated db/db mice. It was observed that GLUT-4 expression and glucose uptake were up-regulated by thiacremonone in 3T3-L1 adipocytes. Thiacremonone treatment also suppressed expression levels of acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), which are involved in lipid metabolism, in the liver of db/db mice. In addition, thiacremonone enhanced peroxisome proliferator-activated receptor γ (PPARγ) expression in the fatty liver. Taken together, these results suggest that thiacremonone may play a vital role in improving the management of obesity and related metabolic syndromes via inhibition of lipid accumulation., (Copyright © 2012 John Wiley & Sons, Ltd.)

The discovery of NF-κB signaling pathways has greatly enhanced our understanding of inflammatory and immune responses. In the canonical NF-κB pathway, the proteasomal degradation of IκBα, an inhibitory protein of NF-κB, is widely accepted to be a key regulatory step. However, contradictory findings have been reported as to whether the immunoproteasome plays an obligatory role in the degradation of IκBα and activation of the canonical NF-κB pathway. Such results were obtained mainly using traditional gene deletion strategies. Here, we have revisited the involvement of the immunoproteasome in the canonical NF-κB pathway using small molecule inhibitors of the immunoproteasome, namely UK-101 and LKS01 targeting β1i and β5i, respectively. H23 and Panc-1 cancer cells were pretreated with UK-101, LKS01 or epoxomicin (a prototypic inhibitor targeting both the constitutive proteasome and immunoproteasome). We then examined whether these pretreatments lead to any defect in activating the canonical NF-κB pathway following TNFα exposure by monitoring the phosphorylation and degradation of IκBα, nuclear translocation of NF-κB proteins and DNA binding and transcriptional activity of NF-κB. Our results consistently indicated that there is no defect in activating the canonical NF-κB pathway following selective inhibition of the immunoproteasome catalytic subunits β1i, β5i or both using UK-101 and LKS01, in contrast to epoxomicin. In summary, our current results using chemical genetic approaches strongly support that the catalytic activity of the immunoproteasome subunits β1i and β5i is not required for canonical NF-κB activation in lung and pancreatic adenocarcinoma cell line models.

Resveratrol (Res), from the skin of red grapes, induces apoptosis in some malignant cells, but there are no reports on the apoptotic effect of Res on human malignant pleural mesothelioma. We found that Res interacts with specificity protein 1 (Sp1). The IC50 for Res was 17 µM in MSTO-211H cells. Cell viability was decreased and apoptotic cell death was increased by Res (0-60 µM). Res increased the Sub-G1 population in MSTO-211H cells and significantly suppressed Sp1 protein levels, but not Sp1 mRNA levels. Res modulated the expression of Sp1 regulatory proteins including p21, p27, cyclin D1, Mcl-1 and survivin in mesothelioma cells. After treatment with Res, apoptosis signaling cascades were activated by the activation of Bid, Bim, caspase-3 and PARP, upregulation of Bax and downregulation of Bcl-xL. Res (20 mg/kg daily for 4 weeks) effectively suppressed tumor growth in vivo in BALB/c athymic (nu+/nu+) mice injected with MSTO-211H cells, an effect that was mediated by inhibition of Sp1 expression and induction of apoptotic cell death. Our results strongly suggest that Sp1 is a novel molecular target of Res in human malignant pleural mesothelioma.

Background: Although the proteasome is a validated anticancer target, the clinical application of its inhibitors has been limited because of inherent systemic toxicity. To broaden clinical utility of proteasome inhibitors as anticancer agents, it is critical to develop strategies to selectively target proteasomes in cancer cells. The immunoproteasome is an alternative form of the constitutive proteasome that is expressed at high levels in cancer tissues, but not in most normal cells in the body., Methods: To validate the immunoproteasome as a chemotherapeutic target, an immunoproteasome catalytic subunit LMP2-targeting inhibitor and siRNA were used. The sensitivity of PC-3 prostate cancer cells to these reagents was investigated using viability assays. Further, a xenograft model of prostate cancer was studied to test the in vivo effects of LMP2 inhibition., Results: A small molecule inhibitor of the immunoproteasome subunit LMP2, UK-101, induced apoptosis of PC-3 cells and resulted in significant inhibition (~50-60%) of tumour growth in vivo. Interestingly, UK-101 did not block degradation of IκBα in PC-3 cells treated with TNF-α, suggesting that its mode of action may be different from that of general proteasome inhibitors, such as bortezomib, which block IκBα degradation., Conclusion: These results strongly suggest that the immunoproteasome has important roles in cancer cell growth and thus provide a rationale for targeting the immunoproteasome in the treatment of prostate cancer.

PPARγ ligands have been reported to reduce proliferation of human prostate cancer cells. However, the molecular mechanism of PPARγ agonist-induced cell growth inhibition of prostate cancer cells is not clear. GSK-3β expression and NFκB activity have important roles in prostate cancer development. To investigate the mechanisms of the PPARγ agonist-induced prostate cancer cell growth inhibition, we examined the effect of troglitazone on the expression of PPARγ, GSK-3β and activity of NFκB as well as on the prostate cancer cell growth. Troglitazone induced the expression of PPARγ in the nuclear of PC-3 cells, but not in LNCaP cells. Troglitazone (0-16 uM) inhibited cancer cell growth in a similar extend between both cells accompanied by the induction of cell cycle arrest in G(0)/G(1) phase and an increased in the similar extent of apoptotic cell death in concentration dependent manner. Troglitazone inhibited the constitutive expression of GSK-3β and activation of NFκB. Co-treatment of troglitazone with a GSK-3β inhibitor (AR-a014418) or GSK-3β siRNA significantly augmented the inhibitory effect of troglitazone on the NFκB activity and on prostate cancer cell growth inhibition and apoptotic cell death. However, overexpression of GSK-3β hindered troglitazone-induced cell growth inhibition and NFκB inactivation. These results suggest that PPARγ agonist, troglitazone, inhibits prostate cancer cell growth through inactivation of NFκB via suppression of GSK-3β expression.

Several studies have shown physiological functions of interleukin (IL)-32, a novel cytokine. However, the role of IL-32 in cancer development has not been reported. In this study, we showed that IL-32γ inhibited tumor growth in IL-32γ-overexpressing transgenic mice inoculated with melanoma as well as colon tumor growth in xenograft nude mice inoculated with IL-32γ-transfected colon cancer cells (SW620). The inhibitory effect of IL-32γ on tumor growth was associated with the inhibition of constitutive activated nuclear transcription factor-κB (NF-κB) and of signal transducer and activator of transcription 3 (STAT3). The expression of antiapoptotic, cell proliferation and tumor-promoting genes (bcl-2, X-chromosome inhibitor of apoptosis protein (IAP), cellular IAP and cellular FADD-like IL-1β-converting enzyme-inhibitory protein, cyclin D), cyclin-dependent kinase 4, cycolooxygenase-2 and inducible nitric oxide synthase was decreased, whereas the expression of apoptotic target genes (caspase-3 and -9, bax) increased. In tumor, spleen and blood, the number of cytotoxic CD8(+) T cells and CD57(+) natural killer cells and the levels of IL-10 increased, but that of tumor necrosis factor-α (TNF-α), IL-1β and IL-6 decreased. We also found that forced overexpression of IL-32γ inhibited colon cancer cell (SW620 and HCT116) growth accompanied with the inhibition of activated NF-κB and STAT3 in vitro. In addition, when IL-32γ was knocked down by small interfering RNA (siRNA) or neutralized with an anti-IL-32γ antibody, IL-32γ-induced colon cancer cell growth inhibition, the IL-32γ-induced decrease of TNF-α, IL-1 and IL-6 production, and the increase of IL-10 production were abolished. However, siRNA of NF-κB and STAT3 augmented IL-32γ-induced colon cancer cell growth inhibition. These findings indicate significant pathophysiological roles of IL-32γ in cancer development.

Peroxisome proliferator-activated receptor (PPAR)-gamma agonists such as troglitazone, pioglitazone and thiazolidine have been shown to induce apoptosis in human colon cancer cells. The molecular mechanism of PPARgamma agonist-induced apoptosis of colon cancer cells, however, is not clear. Glycogen synthase kinase-3beta (GSK-3beta) is an indispensable element for the activation of nuclear factor-kappa B (NF-kappaB) which plays a critical role in the mediation of survival signals in cancer cells. To investigate the mechanisms of PPARgamma agonist-induced apoptosis of colon cancer cells, we examined the effect of troglitazone (0-16muM) on the activation of GSK-3beta and NF-kappaB. Our study showed that the inhibitory effect of troglitazone on colon cancer cell growth was associated with inhibition of NF-kappaB activity and GSK-3beta expression in a dose-dependent manner. Cells were arrested in G(0)/G(1) phase followed by the induction of apoptosis after treatment of troglitazone with concomitant decrease in the expression of the G(0)/G(1) phase regulatory proteins; Cdk2, Cdk4, cyclin B1, D1, and E as well as in the anti-apoptosis protein Bcl-2 along with an increase in the expression of the pro-apoptosis-associated proteins; Caspase-3, Caspase-9 and Bax. Transient transfection of GSK-3beta recovered troglitazone-induced cell growth inhibition and NF-kappaB inactivation. In contrast, co-treatment of troglitazone with a GSK-3beta inhibitor (AR-a014418) or siRNA against GSK-3beta, significantly augmented the inhibitory effect of troglitazone on the NF-kappaB activity, the cancer cell growth and on the expression of G(0)/G(1) phase regulatory proteins and pro-apoptosis regulatory proteins. These results suggest that the PPARgamma agonist, troglitazone, inhibits colon cancer cell growth via inactivation of NF-kappaB by suppressing GSK-3beta activity., (Copyright 2010 Elsevier Ireland Ltd. All rights reserved.)

Amyloid beta (Abeta)-induced neurotoxicity is a major pathological mechanism of Alzheimer disease (AD). In this study, we investigated the inhibitory effect of l-theanine, a component of green tea (Camellia sinensis), on Abeta(1-42)-induced neuronal cell death and memory impairment. Oral treatment of l-theanine (2 and 4 mg/kg) for 5 weeks in the drinking water of mice, followed by injection of Abeta(1-42) (2 microg/mouse, icv), significantly attenuated Abeta(1-42)-induced memory impairment. Furthermore, l-theanine reduced Abeta(1-42) levels and the accompanying Abeta(1-42)-induced neuronal cell death in the cortex and hippocampus of the brain. Moreover, l-theanine inhibited Abeta(1-42)-induced extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase as well as the activity of nuclear factor kappaB (NF-kappaB). l-Theanine also significantly reduced oxidative protein and lipid damage and the elevation of glutathione levels in the brain. These data suggest that the positive effects of l-theanine on memory may be mediated by suppression of ERK/p38 and NF-kappaB as well as the reduction of macromolecular oxidative damage. Thus, l-theanine may be useful in the prevention and treatment of AD.

The bioactive constituents isolated from the bark of Magnolia officinalis such as magnolol, honokiol and obovatol have anti-inflammatory properties through the inactivation of NF-kappaB which is an important factor in the regulation of inflammatory reaction. We recently isolated neolignan compound, 4-O-methylhonokiol, from M. officinalis. In the present study, we investigated whether or not 4-O-methylhonokiol inhibits inflammatory reaction through the inhibition of NF-B activity [corrected]. The results showed that 4-O-methylhonokiol (2.5-10 microM) inhibited LPS (1 microg/ml)-induced NO generation in macrophage Raw 264.7 cells in a concentration-dependent manner with IC(50) value 9.8 microM. The inhibition of NO generation by 4-O-methylhonokiol was consistent with the inhibitory effect on the expression as well as transcriptional activity of inducible nitric oxide synthase (iNOS). In addition, 4-O-methylhonokiol inhibited the LPS-induced transcriptional and DNA binding activities of NF-kappaB as well as p50 and p65 translocation into the nucleus. Topical application of 4-O-methylhonokiol (0.1-1 mg/ear) inhibited 12-O-tetradecanoylphorbol-13-acetate-induced inflammatory ear edema formation, NF-kappaB activity, and iNOS and COX-2 expression. The present results provided evidence that 4-O-methylhonokiol has anti-inflammatory properties through inhibition of the NF-kappaB pathway, and suggested that 4-O-methylhonokiol can be used as an anti-inflammatory agent.

Chemotherapeutic strategies commonly use multiple agents to overcome drug resistance and to lower drug toxicity. Activation of nuclear factor-kappaB (NF-kappaB) is implicated in drug resistance in cancer cells. Previously, we reported that thiacremonone, a novel sulfur compound isolated from garlic, inhibited NF-kappaB and cancer cell growth with IC(50) values about 100 microg/mL in colon cancer cells. In the present study, we tested whether thiacremonone could increase susceptibility of cancer cells to chemotherapeutics through inactivation of NF-kappaB. Colon cancer cells were cotreated with thiacremonone (50 microg/mL, half dose of IC(50)) and lower doses of each chemotherapeutic agent (half dose of IC(50)) for 24 hours. NF-kappaB activity was completely abrogated in cells treated with a combination of thiacremonone and docetaxel, whereas thiacremonone on its own did not alter NF-kappaB activity. This combined drug effect was also found with other anticancer drugs in colon cancer and in other cancer cells. In good correlation with inhibition of cell growth and NF-kappaB activity, the combination treatment also regulated NF-kappaB target genes. Oral treatment of mice with thiacremonone (1 mg/kg) by administering it in drinking water for 4 weeks significantly augmented docetaxel (1 mg/kg, i.p., four times)-induced decrease of tumor growth accompanied with regulation of NF-kappaB activity and NF-kappaB target genes. These results warrant carefully designed clinical studies investigating the combination of thiacremonone and commonly used chemotherapeutic agents for the treatment of human cancers.

Kaurane diterpene compounds have been known to be cytotoxic against several cancer cells through inhibition of nuclear factor-kappaB (NF-kappaB) activity. Here, we showed that inflexinol, a novel kaurane diterpene compound, inhibited the activity of NF-kappaB and its target gene expression as well as cancer cell growth through induction of apoptotic cell death in vitro and in vivo. These inhibitory effects on NF-kappaB activity and on cancer cell growth were suppressed by the reducing agents DTT and glutathione and were abrogated in the cells transfected with mutant p50 (C62S). Sol-gel biochip and surface plasmon resonance analysis showed that inflexinol binds to the p50 subunit of NF-kappaB. These results suggest that inflexinol inhibits colon cancer cell growth via induction of apoptotic cell death through inactivation of NF-kappaB by a direct modification of cysteine residue in the p50 subunit of NF-kappaB.

Introduction: Sulfur compounds isolated from garlic exert anti-inflammatory properties. We recently isolated thiacremonone, a novel sulfur compound from garlic. Here, we investigated the anti-inflammatory and arthritis properties of thiacremonone through inhibition of NF-kappaB since NF-kappaB is known to be a target molecule of sulfur compounds and an implicated transcription factor regulating inflammatory response genes., Methods: The anti-inflammatory and arthritis effects of thiacremone in in vivo were investigated in 12-O-tetradecanoylphorbol-13-acetate-induced ear edema, carrageenan and mycobacterium butyricum-induced inflammatory and arthritis models. Lipopolysaccharide-induced nitric oxide (NO) production was determined by Griess method. The DNA binding activity of NF-kappaB was investigated by electrophoretic mobility shift assay. NF-kappaB and inducible nitric oxide synthetase (iNOS) transcriptional activity was determined by luciferase assay. Expression of iNOS and cyclooxygenase-2 (COX-2) was determined by western blot., Results: The results showed that topical application of thiacremonone (1 or 2 microg/ear) suppressed the 12-O-tetradecanoylphorbol-13-acetate-induced (1 microg/ear) ear edema. Thiacremonone (1-10 mg/kg) administered directly into the plantar surface of hind paw also suppressed the carrageenan (1.5 mg/paw) and mycobacterium butyricum (2 mg/paw)-induced inflammatory and arthritic responses as well as expression of iNOS and COX-2, in addition to NF-kappaB DNA-binding activity. In further in vitro study, thiacremonone (2.5-10 microg/ml) inhibited lipopolysaccharide (LPS, 1 microg/ml)-induced nitric oxide (NO) production, and NF-kappaB transcriptional and DNA binding activity in a dose dependent manner. The inhibition of NO by thiacremonone was consistent with the inhibitory effect on LPS-induced inducible nitric oxide synthase (iNOS) and COX-2 expression, as well as iNOS transcriptional activity. Moreover, thiacremonone inhibited LPS-induced p50 and p65 nuclear translocation, resulting in an inhibition of the DNA binding activity of the NF-kappaB. These inhibitory effects on NF-kappaB activity and NO generation were suppressed by reducing agents dithiothreitol (DTT) and glutathione, and were abrogated in p50 (C62S)-mutant cells, suggesting that the sulfhydryl group of NF-kappaB molecules may be a target of thiacremonone., Conclusions: The present results suggested that thiacremonone exerted its anti-inflammatory and anti-arthritic properties through the inhibition of NF-kappaB activation via interaction with the sulfhydryl group of NF-kappaB molecules, and thus could be a useful agent for the treatment of inflammatory and arthritic diseases.

Many natural compounds have been shown to prevent cancer cell growth through the redox regulation of transcription factors. NF-kappaB, a redox transcription factor, has been implicated in the apoptotic cell death of several cancer cells. This study examined whether or nor 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyranone (DDMP) isolated from onions can modulate the activity of NF-kappaB, thereby induce the apoptotic cell death of colon cancer cells. Treatment with different DDMP concentrations (0.5-1.5 mg/mL) for various periods (0-48 h) inhibited the growth of colon cancer cells (SW620 and HCT116) followed by the induction of apoptosis in a dose dependent manner. It was also found that DDMP modulated tumor necrosis factor-alpha (TNF-alpha) and tetradeanoyl phorbol acetate (TPA)-induced NF-kappaB transcriptional and DNA binding activity. Moreover, DDMP suppressed the NF-kappaB target anti-apoptotic genes (Bcl-2), whereas it induced the expression of the apoptotic genes (Bax, cleaved caspase-3 and cleaved PARP). These results suggest that DDMP from onions inhibit colon cancer cell growth by inducing apoptotic cell death through the inhibition of NF-kappaB.

Compounds such as S-allylmercaptocysteine, diallyl disulfide, and S-trityl-L-cysteine isolated from garlic have been known to be effective in chemoprevention. Nuclear transcription factor-kappaB (NF-kappaB) has been known to be an implicated factor in apoptotic cell death of several cancer cells. In this study, we investigated whether a sulfurcompound (named thiacremonone) isolated from garlic could modulate NF-kappaB activity and thereby induce apoptotic cell death of colon cancer cells. Treatment with different concentrations (30 - 150 microg/ml) of thiacremonone for various periods (0 - 48 h) inhibited colon cancer cell (SW620 and HCT116) growth followed by induction of apoptosis in a dose-dependent manner. We also found that thiacremonone modulated tumor necrosis factor-alpha (TNF-alpha) and tetradeanoyl phorbol acetate (TPA)-induced NF-kappaB transcriptional and DNA binding activity. Moreover, thiacremonone suppressed NF-kappaB target anti-apoptotic genes (Bcl-2, cIAP1/2, and XIAP) and inflammatory genes (iNOS and COX-2), whereas it induced apoptotic genes (Bax, cleaved caspse-3, and cleaved PARP) expression. These results suggest that a novel sulfurocompound from garlic inhibited colon cancer cell growth through induction of apoptotic cell death by modulating of NF-kappaB.

Cinnamaldehyde derivatives isolated from Cinnamomum cassia have been widely used for treating dyspepsia, gastritis, and inflammatory disease as well as cancer. To investigate the anti-tumor activities of several cinnamaldehyde derivatives, we compared the inhibitory effect of cinnamaldehyde derivatives on cell growth and AP-1 transcriptional activity in SW620 human colon cancer cells since AP-1 is a transcriptional factor implicated to control cancer cell growth. Among the derivatives, 2'-hydroxycinnamaldehyde (HCA) most significantly inhibited cancer cell growth and AP-1 transcriptional activity in a dose-dependent manner with an IC50 value of 12.5 and 9 microg/ml, respectively. In further studies on the mechanism, we found that consistent with the inhibitory effect on cell growth, HCA dose-dependently (0-20 microg/ml) inhibited DNA binding activity of AP-1 accompanied with down regulation of c-Jun and c-Fos expressions. HCA also induced apoptotic cell death as well as expression of the apoptosis-regulating gene caspase-3, but inhibited the anti-apoptosis regulating gene bcl-2 in a dose-dependent manner. These results suggested that HCA has the most potent inhibitory effect against human colon cancer cell growth, and AP-1 may be an important target of HCA.