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ABSTRACT: Recent studies have suggested that the anti-cancer activity of CpG-oligodeoxynucleotides (CpG-ODNs) is owing to their immunomodulatory effects in tumor-bearing host. The purpose of this study is to investigate the directly cytotoxic activity of KSK-CpG, a novel CpG-ODN with an alternative CpG motif, against A20 and EL4 lymphoma cells in comparison with previously used murine CpG motif (1826-CpG). To evaluate the potential cytotoxic effects of KSK-CpG on lymphoma cells, cell viability assay, confocal microscopy, flow cytometry, DNA fragmentation, Western blotting, and reverse transcription-polymerase chain reaction (RT-PCR) analysis were used. We found that KSK-CpG induced direct cytotoxicity in A20 lymphoma cells, but not in EL4 lymphoma cells, at least in part via TLR9-mediated pathways. Apoptotic cell death was demonstrated to play an important role in CpG-ODNs-induced cytotoxicity. In addition, both mitochondrial membrane potential decrease and G1-phase arrest were involved in KSK-CpG-induced apoptosis in A20 cells. The activities of apoptotic molecules such as caspase-3, PARP, and Bax were increased, but the activation of p27 Kip1 and ERK were decreased in KSK-CpG-treated A20 cells. Furthermore, autocrine IFN-γ partially contributed to apoptotic cell death in KSK-CpG-treated A20 cells. Collectively, our findings suggest that KSK-CpG induces apoptotic cell death in A20 lymphoma cells at least in part by inducing G1-phase arrest and autocrine IFN-γ via increasing TLR9 expression, without the need for immune system of tumor-bearing host. This new understanding supports the development of TLR9-targeted therapy with CpG-ODN as a direct therapeutic agent for treating B lymphoma.
Molecular Immunology 01/2013; 54(3-4):327-337. · 2.90 Impact Factor
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ABSTRACT: Stress-responsive genes play critical roles in many biological functions that includes apoptosis, survival, differentiation
and regeneration. We have identified a novel stress-responsive gene called BRE which interacts with TNF-receptor-1 and blocks the apoptotic effect of TNF-α. BRE enhances tumor growth in vivo and is up-regulated in hepatocellular and esophageal carcinomas. BRE also regulates the ubiquitination of the DNA repair complex BRCC, and the synthesis of steroid hormones. Here, we examined
BRE-mRNA in cells after treatments with UV and ionizing radiation (IR). UV and IR treatment alone suppressed BRE-mRNA levels by more than 90% at 24h, while hydroxyurea, fluorodeoxyuridine, aphidicolin, known inhibitors of S-phase DNA
synthesis, had no significant effect. BRE protein expression was unaltered in cells treated with TNF-α, Interleukin-1 and Dexamethasone, while a threefold increase
was observed following chorionic gonadotropin exposure. Although BRE plays a regulatory role in many different pathways, yet its expression is apparently under very stringent control.
Molecular Biology Reports 04/2012; 37(1):363-368. · 2.93 Impact Factor
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ABSTRACT: Bambusae caulis in Liquamen (BCL), traditional herbal medicine used in East Asia, is known to have antioxidative and immune-regulating properties. We hypothesized that the potential antioxidant effects of BCL might suppress the production of thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) in human keratinocytes (HaCaT cell). The immune-regulating effect of BCL was demonstrated by antioxidant capacity using DPPH analysis and DCFH-DA analysis. We found that BCL had strong ROS scavenge effect in HaCaT cell. BCL also showed suppression of IFN-γ-induced expression of TARC and MDC, activation of NF-κB, and, moreover, significant block of IFN-γ-induced degradation and phosphorylation of IκB. However, it had no effects on phosphorylation of p38 MAPK. Collectively, these results suggest that BCL may have a therapeutic potential on skin disease such as atopic dermatitis by inhibiting Th2 chemokines which is due, at least in part, to its antioxidant capacities.
Evidence-based Complementary and Alternative Medicine 01/2012; 2012:617494. · 4.77 Impact Factor
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ABSTRACT: PTEN has been considered as one of the important anti-oncogenes, which possesses very wide biological activities. Endogenous PTEN genes begin to express in epiblast during chick embryo gastrulation, and then the expression extends to neural plate and mesoderm. This suggests that PTEN might be involved in cell migration, proliferation, and differentiation during early embryo development. In this study, we employed in vivo approach to explore if endogenous PTEN participates in EMT (Epithelial-mesenchymal transition) in early chick embryo. PTEN was initially detected to highly express in primitive streak during chick gastrulation, in which EMT occurs, and subsequently mesoderm structure such as somites etc. Then, overexpression of both Wt PTEN-GFP and Wt PTEN-GFP positive transplantation of primitive streak resulted in cell accumulation in primitive streak in the development hereafter, indicating that EMT was blocked in both of our assays, either whole embryo transfection of Wt PTEN-GFP or transplantation of Wt PTEN-GFP primary streak tissue. Finally down-regulation of PTEN gene in one side using PTEN siRNA led to reduce the more number of mesoderm cells in PTNE siRNA side than normal side, which suggests that PTEN gene is probably involved in regulating EMT process in development of early embryonic gastrulation.
Hereditas (Beijing) 06/2011; 33(6):613-9.
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ABSTRACT: The increased generation of reactive oxygen species (ROS) induces inflammation in different cell types. However, it is unclear whether ROS play an essential role in the production of thymus and activation-regulated chemokine (TARC/CCL17) and macrophage-derived chemokine (MDC/CCL22) in keratinocytes. Here, we investigated the function of ROS in the production of these two Th2 chemokines in interferon-gamma (IFN-γ)-treated HaCaT keratinocytes. We found that IFN-γ-induced production of both chemokines in parallel with the increased generation of intracellular ROS. A ROS scavenger, N-acetyl cysteine (NAC), significantly inhibited the IFN-γ-induced production of chemokines as well as the activation of I kappa-B (IκB)-nuclear factor-kappa B (NF-κB). Inhibitors of Janus family kinases (JAKs), p38 mitogen-activated kinase (MAPK), and NF-κB suppressed IFN-γ-induced production of TARC and MDC. NF-κB activation was inhibited by both inhibitors of JAKs and p38 MAPK. Importantly, IFN-γ-stimulated phosphorylation of p38 MAPK was significantly suppressed by JAKs inhibitors, but not significantly affected by NAC or L-buthionine sulfoximine (L-BSO). However, IFN-γ-stimulated activation of IκB and NF-κB was suppressed by NAC but enhanced by BSO. Furthermore, inhibition of p38 MAPK and JAKs did not affect ROS generation in IFN-γ-stimulated HaCaT cells. These results indicate that intracellular ROS and JAKs/p38 MAPK both contribute independently to IFN-γ-stimulated production of TARC and MDC in HaCaT keratinocytes, by increasing NF-κB activation.
Journal of Cellular Physiology 01/2011; 226(1):58-65. · 3.87 Impact Factor
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ABSTRACT: Recent studies have suggested that oxidative stress may play a role in the cytotoxic activity of statins against cancer cells. The objective of this study was to elucidate the role of oxidative stress in the cytotoxicity of simvastatin in murine CT26 colon carcinoma cells and B16BL6 melanoma cells. We found that CT26 cells were more sensitive to simvastatin than B16BL16 cells. Interestingly, exposure to simvastatin causes significant apoptotic cell death and perturbations in parameters indicative of oxidative stress in CT26 cells. Moreover, the increase in oxidative stress parameters and cell death were suppressed by isoprenoids including mevalonolactone, farnesyl pyrophosphate ammonium salt, geranylgeranyl pyrophosphate ammonium salt, and coenzyme Q10, and by antioxidants including N-acetyl cysteine, reduced glutathione, superoxide dismutases (SOD), and catalase (CAT) alone or in combination, but were promoted by an inhibitor of glutathione synthesis, L-buthionine-sulfoximine. The signaling pathway induced by simvastatin breaks down the antioxidant defense system by suppressing the expression of reactive oxygen species scavengers, particularly Mn-SOD, CAT, GPx1, and SESN 3, thereby inducing oxidative stress and apoptotic cell death. Collectively, our results demonstrate that simvastatin induces colon cancer cell death at least in part by increasing intracellular oxidative stress and inducing apoptosis.
Toxicology Letters 09/2010; 199(3):277-87. · 3.23 Impact Factor
