Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study examined the interaction of the poorly metastatic human melanoma cell line M4Be and the highly metastatic clone 4 derived from M4Be, with respect to fresh adherent leukocytes (AL) isolated from 17 different healthy blood donors. These AL contained 80% (73%-93%) monocytes, 15% (6%-20%) B lymphocytes and 5% (1%-8%) T lymphocytes. The survival of these tumor cells against the stress exerted by these AL was estimated with a clonogenic assay where isolated tumor cells were co-cultured for 14 days in contact with AL and lipopolysaccharide (LPS). For a given blood donor, AL either stimulates or inhibits the colony formation of the tumor cells (T) depending on the AL/T ratio, the AL activation status and the metastatic potential of tumor cells. At low AL/T ratios (< 10/1) in the presence of low (8 ng/ml) and trace (8 pg/ml) levels of LPS, hydrogen peroxide (H2O2) release is significantly reduced, and tumor cells significantly increase their colony formation; the feeder effect of AL is suggested to be due to low concentrations of soluble tumor necrosis factor-alpha (TNF-alpha). At high AL/T ratios (> 10/1), whatever the characteristics of the blood donor, clone 4 is significantly more sensitive than M4Be to AL activated with medium containing low (8 ng/ml) or high (1,000 ng/ml) levels of LPS; this killing effect is suggested to be due to TNF-alpha, both soluble and membrane-bound, but not to be due to release of H2O2. These data suggest that the regulatory role of AL, which remove the majority of human melanoma cells and stimulate the colony formation of a small fraction of them, is partly due to TNF-alpha.
 ...
PMID:Sensitivity of human melanoma cells to adherent leukocytes depends on the ratio between them, the activation status of adherent leukocytes and the metastatic potential of tumor cells. 1145 70

Nitric oxide (NO) is known to facilitate tumour metastasis through the promotion of angiogenesis, vascular dilation, platelet aggregation, etc. In the present study we explored its novel role in producing dysfunction of the host immune system in the metastasis of murine metastatic melanoma B16-BL6 cells. A significant reduction in the mixed lymphocyte reaction (MLR) was observed in the spleen cells from B16-BL6-bearing mice, but not in those from mice bearing the parent cell B16. When B16-BL6 cells were added in vitro to the MLR, a significant decrease was also found, even when they were co-cultured with the lymphocytes in two compartments of a Transwell chamber separated by an 8.0 microm filter. The supernatant from cultured B16-BL6 but not B16 cells, which had a greatly increased NO activity, significantly inhibited concanavalin A- and lipopolysaccharide-induced lymphocyte proliferation. A remarkably higher expression of inducible NO synthase (iNOS) was detected in B16-BL6 cells than in B16 cells. Nomega-Nitro-l-arginine (l-NNA), a NO synthase inhibitor and superoxide dismutase, significantly antagonized the above inhibition by B16-BL6 cells, while l-arginine, a NO precursor, and S-nitroso-N-acetyl-d,l-penicillamine, a NO donor, strengthened the inhibition. Furthermore, l-NNA significantly inhibited lung metastasis of B16-BL6 cells, while l-arginine tended to enhance the metastasis. The cytotoxicity of B16-BL6-specific T-cells was significantly decreased by pre-culture with B16-BL6 cells in a Transwell chamber or the culture supernatants of B16-BL6 cells, whereas l-iminoethyl-lysine, a selective inhibitor of iNOS, showed a significant recovery from the disease. These results suggest that NO released by metastatic tumour cells may impair the immune system, which facilitates the escape from immunosurveillance and metastasis of tumour cells.
Melanoma Res 2001 Dec
PMID:Metastatic melanoma cells escape from immunosurveillance through the novel mechanism of releasing nitric oxide to induce dysfunction of immunocytes. 1172 2

Cancer vaccine trials require sensitive assays for evaluating T-cell responses in immunized patients. In addition, these methods are used for identifying novel tumor-associated antigens (TAA). Therefore, our aim was to improve the methods for evaluating patients receiving the cancer vaccines by enhancing the in vitro detection of tumor-specific T cells from the peripheral blood. We have developed an efficient and reproducible method for detecting tumor-specific T cells by optimizing the activation of antigen presenting cells (APC) in peripheral blood mononuclear cells (PBMC) of metastatic melanoma patients with soluble trimeric CD40-ligand (CD40L) or lipopolysaccharide (LPS). This method significantly improved the generation of Melan-A/MART-1:27-35 and Melan-A/MART-1:26-35(27L) peptide/tumor-specific cells as well as lower frequency tyrosinase:368-376(370D) specific T cells from the PBMC of melanoma patients. T-cell enhancement from activated PBMC cultures was found to be reproducible within individual patients and was observed after the addition of either CD40L or LPS to PBMC cultures. Additionally, PBMC activation improved the detection of tumor-specific precursors from melanoma patients previously immunized with peptides derived from Melan-A/MART-1, tyrosinase and gp100. Collectively, these findings describe a novel approach for evaluating patients receiving the cancer vaccines and may provide a useful method for the characterization of novel tumor-associated antigens.
 ...
PMID:CD40 ligand and lipopolysaccharide enhance the in vitro generation of melanoma-reactive T-cells. 1173 Aug 53

Biological activities of five Veronica species (Scrophulariaceae), V. cymbalaria, V. hederifolia, V. pectinata var. glandulosa, V. persica and V. polita were studied for their anti-inflammatory and cytotoxic activities. Their methanol extracts showed both the inhibitory activity of nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated macrophages and cytotoxic activity against KB epidermoid carcinoma and B16 melanoma. When the methanol extracts were fractionated between water and chloroform, water fractions significantly inhibited NO production without any cytotoxicity, while chloroform fractions showed cytotoxicity dose-dependently. When the radical scavenging activity was determined using 2,2-diphenyl-1-picryl-hydrazyl (DPPH), water fractions of the five Veronica species scavenged free radicals effectively, suggesting that the inhibitory effect of this species on NO production was due to their radical scavenging activity. On the other hand, chloroform fractions of Veronica species except for V. cymbalaria showed similar cytotoxic activity against KB and B16 melanoma cells.
 ...
PMID:Anti-inflammatory and cytotoxic activities of five Veronica species. 1199 29

We have previously shown that circulating intravascular cells generally arrest by mechanical restriction in the hepatic sinusoids, causing rapid release of nitric oxide (NO) which is cytotoxic to these cells and inhibits their growth into metastatic tumours. Here, we present evidence that these NO-dependent cytotoxic mechanisms are susceptible to upregulation by lipopolysaccharide (LPS). Five x 10(5) fluorescently labelled melanoma cells were injected into the mesenteric vein of C57BL/6 mice to effect their localisation in the hepatic microvasculature. Test mice were then given 1 mg/kg LPS intraperitoneally (i.p.) to activate the microvascular cells. By electron paramagnetic resonance (EPR) spectroscopy, the expression of NO in the liver was significantly increased by 8 h in the LPS-treated mice. The non-selective NO synthase inhibitor L-NAME inhibited the induction of NO by LPS, while its inactive enantiomer D-NAME had no significant effect. Using immunohistochemistry (IHC), iNOS-positive microvascular cells were detected in the terminal portal venule (TPV) region of the liver 8 h after LPS stimulation. LPS treatment also increased the retention of melanoma cells in the liver between 8 and 24 h, especially in the TPV region. Eight hours after cell injection, local expression of VCAM-1 and ICAM-1 was detected by double-label immunohistochemistry at the sites of tumour cell arrest. Expression of these adhesion molecules was enhanced in mice treated with LPS. Using flow cytometry, 98% of the B16F1 melanoma cells expressed VLA-4, the counter receptor of VCAM-1, and approximately 1.5% expressed LFA-1, the counter receptor of ICAM-1. LPS did not significantly alter the expression of either counter receptor on melanoma cells in vitro or in vivo. By DNA end-labelling, the rates of melanoma cell apoptosis were significantly increased from 8 to 24 h in the TPV region (but not in the sinusoids) of LPS-treated mice. Fourteen days after tumour cell injection, the LPS-treated mice had a significantly smaller hepatic metastatic tumour burden than the control mice. These data suggest that LPS can inhibit the metastasis of melanoma cells in the liver by inducing the expression of NO and adhesion molecules by the hepatic endothelium. The induction of iNOS and the inducible cytotoxic effect of LPS appear to be primarily located within the TPV region of the liver acinus.
 ...
PMID:Regulation of B16F1 melanoma cell metastasis by inducible functions of the hepatic microvasculature. 1204 14

Shichimotsu-koka-to (SKT) is a Kampo (traditional Japanese herbal) medicine, which is used in Japan to treat hypertension and atherosclerosis. We investigated the inhibitory effect of SKT on experimental pulmonary metastasis of B16 melanoma cells. The intake of SKT at a dose of 430 mg/kg for 6 weeks from 2 weeks before tumor inoculation significantly reduced the number of metastatic surface nodules in the lung and extended the life span. When the duration of SKT intake was examined, survival time was not affected by preintake before B16 melanoma cell inoculation and was slightly extended by postintake after B16 melanoma cell inoculation, although the life span was prolonged by intake throughout the experiment. To address the mechanism underlying the antimetastatic effect of SKT, we studied whether SKT modulated macrophage function, which is involved in killing tumor cells. The intake of SKT for 6 weeks dose dependently increased nitric oxide (NO) production by macrophages following stimulation with lipopolysaccharide. The elevated NO was found to serve as a cytotoxic mediator against B16 melanoma cells in co-culture with macrophages. On the contrary, B16 melanoma-conditioned medium reduced NO production by macrophages. However, SKT treatment reversed the reduction in NO production by the conditioned medium significantly. These findings may suggest that macrophage function-modulating activity by SKT appears to underlie its antimetastatic activity, which leads to a decrease in the number of lung metastatic surface nodules and the extension of life span.
 ...
PMID:Suppressive effect of Shichimotsu-koka-to (Kampo medicine) on pulmonary metastasis of B16 melanoma cells. 1213 62

In the present study, B16 melanoma cells were found to produce inhibitory and cytotoxic substances with a molecular weight lower than 3000 Da against macrophages in a conditioned medium. The B16 melanoma-conditioned medium suppressed nitric oxide (NO) production only by mouse peritoneal macrophages and the mouse macrophage-like cell line, RAW264.7 cells, but not by rat peritoneal macrophages. In addition, it showed cytotoxicity against mouse peritoneal macrophages and mouse macrophage-like cell lines, RAW264.7 and J774A.1 cells, but not against rat cells (peritoneal macrophages, 3Y1, hepatocytes), human cells (HeLa, KB, MCF-7), or mouse 3T3-L1 cells. The inhibitory activity of NO production was not affected by trypsin treatment or arginine supplementation, but it was abolished by heat treatment at 95 degrees C for 3 min. On the other hand, the cytotoxicity was not influenced by these treatments. Inducible NO synthase induction following lipopolysaccharide stimulation was reduced by treatment of mouse peritoneal macrophages with B16 melanoma-conditioned medium. These results suggest that metastatic B16 melanoma cells produce two distinct substances: to suppress NO production by macrophages and to kill macrophages and macrophage-like cell lines. We propose that these activities may help metastatic B16 melanoma cells to escape a host immunosurveillance system and to metastasize to target organs.
 ...
PMID:Suppression of macrophage function by substances with a molecular weight lower than 3000 Da in B16 melanoma-conditioned medium. 1213 67

Tumor-associated macrophages (TAM) have been shown to play an important role in tumor angiogenesis. The purpose of this study was to determine whether monocyte recruitment, activation and differentiation mediated by monocyte chemotactic protein-1 (MCP-1) and macrophage colony stimulating factor (M-CSF) modulate the expression of the angiogenic factor, Interleukin (IL)-8. Isolated human peripheral blood monocytes secreted low basal levels of IL-8. Incubation of monocytes with M-CSF or MCP-1 resulted in an up-regulation of IL-8 mRNA and protein expression. The differential expression of IL-8 by monocytes following MCP-1 and M-CSF treatments involved activation of the NFkB transcription factor. Further activation with lipopolysaccharide (LPS) caused an increase in IL-8 secretion in monocytes but not in monocyte-derived macrophages (MDM). MDM-conditioned media significantly up-regulated IL-8 expression in human malignant melanoma cells in vitro. In summary, we demonstrated that MCP-1 and M-CSF, critical for monocyte recruitment, activation and differentiation, differentially regulate IL-8 expression and may play an important role in monocyte/macrophage-mediated tumor angiogenesis.
 ...
PMID:Monocyte/macrophage recruitment, activation and differentiation modulate interleukin-8 production: a paracrine role of tumor-associated macrophages in tumor angiogenesis. 1249 91

Proteins containing PAAD [pyrin, AIM (absent-in-melanoma), ASC [apoptosis-associated speck-like protein containing a CARD (caspase-recruitment domain)] and DD (death domain)-like] (PYRIN, DAPIN) domains are involved in innate immunity, regulating pathways leading to nuclear-factor-kappa B (NF-kappa B) and pro-caspase-1 activation. Many PAAD-family proteins have structures reminiscent of Nod-1, a putative intracellular sensor of lipopolysaccharide. Hereditary mutations in some of the PAAD-family genes are associated with auto-inflammatory diseases. Several of these proteins utilize the bipartite PAAD- and CARD-containing adapter protein ASC/TMS-1 (target of methylation-induced silencing) for linking to downstream signalling pathways. In the present paper, we describe characterization of human PAAD-only protein-1 (POP1)/ASC2, which is highly homologous with the PAAD domain of ASC, and which probably originated by gene duplication on chromosome 16. We demonstrate that POP1/ASC2 associates with ASC via PAAD-PAAD interactions and modulates NF-kappa B and pro-caspase-1 regulation by this adapter protein. In gene transfer experiments, POP1/ASC2 suppressed cytokine-mediated NF-kappa B activation similar to other PAAD-family proteins previously tested. Immunohistochemical studies showed expression of POP1/ASC2 predominantly in macrophages and granulocytes. We propose that POP1/ASC2 functions as a modulator of multidomain PAAD-containing proteins involved in NF-kappa B and pro-caspase-1 activation and innate immunity.
 ...
PMID:The PAAD/PYRIN-only protein POP1/ASC2 is a modulator of ASC-mediated nuclear-factor-kappa B and pro-caspase-1 regulation. 1293 66

Dendritic cells (DCs)-based immunotherapy is a new strategy for cancer treatment and has been used in some clinical trials against cancer, including melanoma, and has shown promising results. However, the conventional protocol of DC immunotherapy may not be effective for hepatocellular carcinoma (HCC) because of impaired DC maturation in HCC patients. In order to induce sufficient maturation on HCC derived DCs, we tested various stimuli such as tumor necrosis factor (TNF) alpha, lipopolysaccharide (LPS), interferon (IFN)gamma and CD40-ligand. In stimulating with LPS + IFNgamma, DCs of HCC patients expressed significantly high levels of CD86 (p < 0.05) and produced high levels of IL-12 as compared to DCs stimulated with TNFalpha alone. Moreover, it showed better ability to stimulate allogeneic mixed lymphocyte reaction. It concluded that LPS and IFNgamma was the best combination of stimuli for induction of sufficient maturation on DCs derived from HCC.
 ...
PMID:Potent stimuli combined with lipopolysaccaride and IFNgamma may improve immunotherapy against HCC by increasing the maturation and subsequent immune response of the dendritic cells. 1266 3


<< Previous 1 2 3 4 5 6 7 8 9 10