20,377 research outputs found

    Chemoattractant Signaling between Tumor Cells and Macrophages Regulates Cancer Cell Migration, Metastasis and Neovascularization

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    Tumor-associated macrophages are known to influence cancer progression by modulation of immune function, angiogenesis, and cell metastasis, however, little is known about the chemokine signaling networks that regulate this process. Utilizing CT26 colon cancer cells and RAW 264.7 macrophages as a model cellular system, we demonstrate that treatment of CT26 cells with RAW 264.7 conditioned medium induces cell migration, invasion and metastasis. Inflammatory gene microarray analysis indicated CT26-stimulated RAW 264.7 macrophages upregulate SDF-1α and VEGF, and that these cytokines contribute to CT26 migration in vitro. RAW 264.7 macrophages also showed a robust chemotactic response towards CT26-derived chemokines. In particular, microarray analysis and functional testing revealed CSF-1 as the major chemoattractant for RAW 264.7 macrophages. Interestingly, in the chick CAM model of cancer progression, RAW 264.7 macrophages localized specifically to the tumor periphery where they were found to increase CT26 tumor growth, microvascular density, vascular disruption, and lung metastasis, suggesting these cells home to actively invading areas of the tumor, but not the hypoxic core of the tumor mass. In support of these findings, hypoxic conditions down regulated CSF-1 production in several tumor cell lines and decreased RAW 264.7 macrophage migration in vitro. Together our findings suggest a model where normoxic tumor cells release CSF-1 to recruit macrophages to the tumor periphery where they secrete motility and angiogenic factors that facilitate tumor cell invasion and metastasis

    The Antiviral Effect of High-Molecular Weight Poly-Gamma-Glutamate against Newcastle Disease Virus on Murine Macrophage Cells

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    This study demonstrates the capacity of HM-γ-PGA treatment to significantly protect murine macrophage cells (RAW 264.7 cells) against NDV infection. Such protection can be explained by the induction of antiviral state of HM-γ-PGA in RAW 264.7 cells via TLR4-mediated IRF-3, IRF-7, IFN-β, and IFN-related gene induction as shown in time-dependent changes in mRNA expression confirmed by polymerase chain reaction (PCR). Moreover, the present research also showed that HM-γ-PGA can induce proinflammatory cytokine secretion in RAW 264.7 as measured by enzyme-linked immunosorbent assay (ELISA). Therefore, our findings suggest that HM-γ-PGA can be a potential antiviral substance that can inhibit NDV infection through its stimulation of antiviral state on RAW 264.7 cells. These results have been consistent with the previous studies showing that HM-γ-PGA can protect RAW 264.7 cells and mice against influenza infection. However, it should be noted that although murine macrophage cells are susceptible to NDV, they are not the natural host cells of the virus; thus further in vivo and in vitro studies involving chicken and chicken immune cells are needed to fully assess the efficacy and applicability of HM-γ-PGA in the poultry industry

    Effects of quinoline-arylamidine hybrids on LPS-induced inflammation in RAW 264.7 cells

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    Background and purpose: Inflammation is a common pathogenesis in infection, injury, cancer, and many chronic diseases. Macrophages are among the main cells involved in generation of inflammation. The aim of the present study was to investigate the effects of molecular hybrids with 7-chloroquinoline and arylamidine moieties joined through flexible a 2-aminoethanol linker, on the in vitro inflammatory responses to lipopolysaccharides (LPS) induced inflammation in the RAW 264.7&nbsp;cells. Materials and methods: To determine effects of seven quinoline-arylamidine hybrids on the growth of the murine macrophage-like (RAW 264.7) cells MTT assay was used. Inflammatory reactions in the RAW264.7 cells were induced using E. coli lipopolysaccharides (LPS). Levels of nitric oxide (NO) and malondialdehyde (MDA) were determined by spectrophotometry methods. Intracellular production of reactive oxygen species (ROS) was measured by flow cytometry. Antioxidant capacity of tested compounds was tested by 2,2\u27-azino-bis(3-ethybenzthiazoline-6-sulfonic acid (ABTS) radical cation method. Results: Tested hybrid compounds differentially influenced proliferation of non-stimulated and LPS-stimulated RAW 264.7 cells. The hybrid compounds have not presented ABTS radical-scavenger activity. In the LPS-stimulated RAW 264.7 cells 10 μM compounds slightly decreased production of NO and ROS and significantly modulated LPS-induced lipid peroxidation. Conclusions: Molecular hybrids with 7-chloroquinoline and arylamidine moieties joined through flexible 2-aminoethanol linker markedly decreased accumulation of lipid peroxidation products in the LPS-stimulated RAW 264.7 cells. Further studies are necessary to determine their mechanism of anti-inflammatory action in more details. &nbsp; Keywords: Hybrid molecules, 7-Chloroquinoline, Aromatic amidine, Anti-inflammatory activity in vitro</p

    Inhibition of vacuolar-type (H+)-ATPase by the cytostatic macrolide apicularen A and its role in apicularen A-induced apoptosis in RAW 264.7 cells

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    AbstractApicularen A and the known vacuolar-type (H+)-ATPase (V-ATPase) inhibitor bafilomycin A1 induced apoptosis of RAW 264.7 cells, while apicularen B, an N-acetyl-glucosamine glycoside of apicularen A, was far less effective. Apicularen A inhibited vital staining with acridine orange of the intracellular organelles of RAW 264.7 cells, inhibited the ATP-dependent proton transport into inside-out microsome vesicles, and inhibited the bafilomycin A1-sensitive ATP hydrolysis. The IC50 values of the proton transport were 0.58nM for apicularen A, 13nM for apicularen B, and 0.95nM for bafilomycin A1. Furthermore, apicularen A inhibited the bafilomycin A1-sensitive ATP hydrolysis more potently than apicularen B. F-ATPase and P-ATPase were not inhibited by apicularen A. We concluded that apicularen A inhibits V-ATPase, and thus induces apoptosis in RAW 264.7 cells

    Platelet-Rich Fibrin Reduces IL-1β Release from Macrophages Undergoing Pyroptosis.

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    BACKGROUND Pyroptosis is a catabolic process relevant to periodontal disorders for which interleukin-1β (IL-1β) inflammation is central to the pathophysiology of the disease. Despite platelet-rich fibrin (PRF) anti-inflammatory properties and its application to support periodontal regeneration, the capacity of PRF to modulate pyroptosis, specifically the production and release of IL-1β, remains unknown. The question arises whether PRF could regulate IL-1β release from macrophages in vitro. METHODS To answer this question, RAW 264.7 macrophages and primary macrophages obtained from murine bone marrow were primed with PRF before being challenged by lipopolysaccharide (LPS). Cells were then analysed for the pyroptosis signalling components by gene expression analyses and IL-1β secretion at the protein level. The release of mitochondrial reactive oxygen species (ROS) was also detected. RESULTS PRF lowered the LPS-induced expression of IL-1β and NLRP3 inflammasome, caspase-11 and IL-18 in primary macrophages, and IL-1β and caspase-11 in RAW 264.7 cells. Additionally, PRF diminished the secretion of IL-1β at the protein level in LPS-induced RAW 264.7 cells. This was shown through immunoassays performed with the supernatant and further confirmed by analysing the lysates of permeabilised cells. Furthermore, PRF reduced the ROS release provoked by LPS in RAW 264.7 cells. Finally, to enhance IL-1β release from the LPS-primed macrophages, we introduced a second signal with adenosine triphosphate (ATP). In this setting, PRF significantly reduced IL-1β release in RAW 264.7 cells and a trend to diminish IL-1β release in primary macrophages. CONCLUSION These findings suggest that PRF can reduce IL-1β release and, at least in part, inhibit pyroptosis-related factors in LPS-challenged macrophages

    Rho iso-alpha acids from hops inhibit the GSK-3/NF-κB pathway and reduce inflammatory markers associated with bone and cartilage degradation

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    <p>Abstract</p> <p>Background</p> <p><it>Rho </it>iso-alpha acids (RIAA) from hops have been shown to have anti-inflammatory properties. To understand the mechanisms, we evaluated the effect of RIAA in cell signaling pathways and inflammatory markers using various in vitro models. We also investigated their therapeutic effect in mice with collagen-induced arthritis.</p> <p>Methods</p> <p>The LPS-stimulated RAW 264.7 macrophages were used to evaluate the effect of RIAA on the NF-κB and MAPK signaling pathways; phosphorylation of ERK1/2, p38 and JNK was assessed by western blotting and NF-κB binding by electrophoretic mobility shift assays. Effect on the NF-κB activity was evaluated by the luciferase reporter assays in LPS-stimulated RAW 264.7 cells. GSK-3α/β kinase activity was measured in cell-free assays. The inhibitory effect of RIAA on inflammatory markers was assessed by measuring nitric oxide in LPS-stimulated RAW 264.7 cells, RANKL-mediated TRAP activity in transformed osteoclasts, and TNF-α/IL-1β-mediated MMP-13 expression in SW1353 cells. Mice with collagen-induced arthritis were fed with RIAA for 2 weeks. Symptoms of joint swelling, arthritic index and joint damage were assessed.</p> <p>Results</p> <p>RIAA selectively inhibited the NF-κB pathway while having no effect on ERK1/2, p38 and JNK phosphorylation in LPS-stimulated RAW 264.7 cells. RIAA also inhibited GSK-3α/β kinase activity and GSK-3β dependent phosphorylation of β-catenin in RAW 264.7 cells. In addition, RIAA inhibited NF-κB-mediated inflammatory markers in various cell models, including nitric oxide in LPS-stimulated RAW 264.7 cells, RANKL-mediated TRAP activity in transformed osteoclasts, and TNF-α/IL-1β-mediated MMP-13 expression in SW1353 human chondrosarcoma cells. Finally, in a mouse model of collagen-induced arthritis, RIAA ameliorated joint damage as evidenced by significant reduction of the arthritis index and histology score; at 250 mg/kg-body weight, RIAA had efficacy similar to that of 20 mg/kg-body weight of celecoxib.</p> <p>Conclusion</p> <p>RIAA may have potential as an anti-inflammatory therapeutic.</p

    Anti-inflammatory effect of neo-lignan isoamericanin A via suppression of NF-κB in liposaccharide-stimulated RAW 264.7 cells

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    Purpose: To investigate the potential anti-inflammatory effects of the seeds of Opuntina humifusa and its active constituents.Methods: The extract of O. humifusa seeds was tested for the inhibition of nitric oxide (NO) production in liposaccharide (LPS)-stimulated RAW 264.7 cells using Griess reagent. The active constituents were isolated using bioassay-guided isolation methods. The effects of the active constituent on NO, proinflammatory cytokines, nuclear factor-kappa B (NF-κB) and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (IκB) were evaluated by enzyme-linked immunosorbent assay (ELISA) and western blot analysis.Results: The seed extract of O. humifusa significantly attenuated LPS-induced NO production in RAW 264.7 cells (p &lt; 0.05). Bioassay-guided fractionation resulted in the isolation of isoamericanin A as an active constituent. Isoamericanin A reduced LPS-induced production of NO, iNOS, and proinflammatory cytokines (TNF-α and IL-6) in a concentration-dependent manner (p &lt; 0.05). Furthermore, the effect was accompanied by decreased translocation of NF-κB from the cytosol to the nucleus and the decreased phosphorylation of IκB in the cytosol induced by LPS (p &lt; 0.05).Conclusion: The seed extract of O. humifusa and its active constituent, isoamericanin A, have antiinflammatory effects in LPS-stimulated RAW 264.7 cells, suggesting that they have potentials as antiinflammatory agents. Keywords: Opuntia humifusa seeds, Isoamericanin A, Nitric oxide, RAW 264.7 cells, NF-kappa
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