Autocrine and Paracrine Regulation of Interleukin-8 Expression in Lung Cancer Cells
We had previously demonstrated that lung cancer cells, upon contact with macrophages, could be induced to secrete angiogenic factors to promote tumor angiogenesis. In this study, we focused on the paracrine and autocrine regulation of interleukin (IL)-8 expression in sensitized lung cancer cells after interacting with macrophages. We found that the IL-8 mRNA expression in lung cancer cells significantly increased after coculture with phorbol myristate acetate-treated THP-1 cells and human primary lung macrophages. Fresh lung cancer CL1-5 cells cocultured with macrophage-sensitized lung cancer cells still had a 35% of increase in IL-8 mRNA expression. The addition of anti-inflammatory agents pyrrolidine dithiocarbamate, pentoxifylline, aspirin, and dexamethasone could completely suppress the expression of IL-8 mRNA in fresh/sensitized lung cancer cell cocultures. Human recombinant tumor necrosis factor (TNF)-alpha and IL-1alpha could induce IL-8 expression in lung cancer cells in a dose-dependent manner. Neutralization with TNF-alpha and IL-1alpha antibodies in cocultures decreased the levels of IL-8 expression in sensitized lung cancer cells. Nuclear factor-kappaB transcriptional activity was also suppressed by the same antibodies, as confirmed by a reporter gene assay and the electrophoretic mobility shift assay. Our results highly suggest that both autocrine and paracrine regulation are involved in IL-8 expression of lung cancer cells cocultured with macrophage. Also, the regulations of IL-8 expression in lung cancer cells were through the nuclear factor-kappaB pathway and modulated by TNF-alpha and IL-1alpha.
Available from: Alexandru Gudima
- "Elevated expression of IL-8 during co-culture with macrophages was also found in several lung cancer, osteogenic sarcoma and hepatoma cell lines (Chen et al., 2003). Up-regulation of IL-8 expression was presumably mediated by TAM-derived TNFα and IL1α, which stimulated NF-κ B activity in tumor cells (Yao et al., 2005). Macrophage-derived TNFα and IL-1α were necessary for the release of IL-8 and VEGF from melanoma cells (Torisu et al., 2000). "
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ABSTRACT: Tumour angiogenesis is an essential process for supplying rapidly growing malignant tissues with essential nutrients and oxygen. An angiogenic switch allows tumour cells to survive and grow, and provides them access to vasculature resulting in metastatic disease. Monocyte-derived macrophages recruited and reprogrammed by tumour cells serve as a major source of angiogenic factors boosting the angiogenic switch. Tumour endothelium releases angiopoietin-2 and further facilitates recruitment of TIE2 receptor expressing monocytes (TEM) into tumor sites. Tumour-associated macrophages (TAM) sense hypoxia in avascular areas of tumours, and react by production of angiogenic factors such as VEGFA. VEGFA stimulates chemotaxis of endothelial cells (EC) and macrophages. In some tumours, TAM appeared to be a major source of MMP9. Elevated expression of MMP9 by TAM mediates extracellular matrix degradation and the release of bioactive VEGFA. Other angiogenic factors released by TAM include bFGF, thymidine phosphorylase (TP), urokinase-type plasminogen activator (uPA), and adrenomedullin. The same factors used by macrophages for the induction of angiogenesis (like VEGF-A and MMP9) support lymphangiogenesis. TAM can express LYVE-1, one of the established markers of lymphatic endothelium. TAM support tumour lymphangiogenesis not only by secretion of pro-lymphangiogenic factors but also by trans-differentiation into lymphatic EC. New pro-angiogenic factor YKL-40 belongs to a family of mammalian chitinase-like proteins (CLP) that act as cytokines or growth factors. Human CLP family comprises YKL-40, YKL-39 and SI-CLP. Production of all three CLP in macrophages is antagonistically regulated by cytokines. It was recently established that YKL-40 induces angiogenesis in vitro and in animal tumour models. YKL-40-neutralizing monoclonal antibody blocks tumour angiogenesis and progression. The role of YKL-39 and SI-CLP in tumour angiogenesis and lymphangiogenesis remains to be investigated.
Available from: Shih-Hurng Loh
- "Oligonucleotides were labeled with digoxigenin-11-dUTP (Roche Molecular Biochemicals) using Klenow polymerase (Invitrogen) and purified by MicroSpin G-50 columns (Amersham Pharmacia). The details of nuclear extract preparation, electrophoresis, and detection have been described previously , . "
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ABSTRACT: Urotensin II (U-II), an 11-amino acid peptide, exerts a wide range of actions in cardiovascular systems. Interleukin-8 (IL-8) is secreted by endothelial cells, thereby enhancing endothelial cell survival, proliferation, and angiogenesis. However, the interrelationship between U-II and IL-8 as well as the detailed intracellular mechanism of U-II in vascular endothelial cells remain unclear. The aim of this study was to investigate the effect of U-II on IL-8 expression and to explore its intracellular mechanism in human umbilical vein endothelial cells.
Primary human umbilical vein endothelial cells were used. Expression of IL-8 was determined by real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and luciferase reporter assay. Western blot analyses and experiments with specific inhibitors were performed to reveal the downstream signaling pathways as concerned. U-II increased the mRNA/protein levels of IL-8 in human umbilical vein endothelial cells. The U-II effects were significantly inhibited by its receptor antagonist [Orn(5)]-URP. Western blot analyses and experiments with specific inhibitors indicated the involvement of phosphorylation of p38 mitogen-activated protein kinase and extracellular signal-regulated kinase in U-II-induced IL-8 expression. Luciferase reporter assay further revealed that U-II induces the transcriptional activity of IL-8. The site-directed mutagenesis indicated that the mutation of AP-1 and NF-kB binding sites reduced U-II-increased IL-8 promoter activities. Proliferation of human umbilical vein endothelial cells induced by U-II could be inhibited significantly by IL-8 RNA interference.
The results show that U-II induces IL-8 expression in human umbilical vein endothelial cells via p38 mitogen-activated protein kinase and extracellular signal-regulated kinase signaling pathways and IL-8 is involved in the U-II-induced proliferation of human umbilical vein endothelial cells.
Available from: Christian Sadik
- "Moreover, IL-8 is associated with shortened survival, particularly in NSCLC [9-12]. Cell culture data suggest that lung carcinoma cells are a highly relevant source of IL-8 in the tumor microenvironment [9,13]. Interestingly, a recent study also demonstrates that IL-8 mediates proliferation of the human NSCLC cell lines A549 and NCI-H292, respectively . "
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ABSTRACT: Production of interferon (IFN)-gamma is key to efficient anti-tumor immunity. The present study was set out to investigate effects of IFNgamma on the release of the potent pro-angiogenic mediator IL-8 by human A549 lung carcinoma cells.
A549 cells were cultured and stimulated with interleukin (IL)-1beta alone or in combination with IFNgamma. IL-8 production by these cells was analyzed with enzyme linked immuno sorbent assay (ELISA). mRNA-expression was analyzed by real-time PCR and RNase protection assay (RPA), respectively. Expression of inhibitor-kappa Balpha, cellular IL-8, and cyclooxygenase-2 was analyzed by Western blot analysis.
Here we demonstrate that IFNgamma efficiently reduced IL-8 secretion under the influence of IL-1beta. Surprisingly, real-time PCR analysis and RPA revealed that the inhibitory effect of IFNgamma on IL-8 was not associated with significant changes in mRNA levels. These observations concurred with lack of a modulatory activity of IFNgamma on IL-1beta-induced NF-kappaB activation as assessed by cellular IkappaB levels. Moreover, analysis of intracellular IL-8 suggests that IFNgamma modulated IL-8 secretion by action on the posttranslational level. In contrast to IL-8, IL-1beta-induced cyclooxygenase-2 expression and release of IL-6 were not affected by IFNgamma indicating that modulation of IL-1beta action by this cytokine displays specificity.
Data presented herein agree with an angiostatic role of IFNgamma as seen in rodent models of solid tumors and suggest that increasing T helper type 1 (Th1)-like functions in lung cancer patients e.g. by local delivery of IFNgamma may mediate therapeutic benefit via mechanisms that potentially include modulation of pro-angiogenic IL-8.
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