Activation of the transcription factor nuclear factor-B (NF-B) has been suggested to participate in chronic disorders, such as diabetes and its complications. In contrast to the short and transient activation of NF-B in vitro, we observed a long-lasting sustained activation of NF-B in the absence of decreased IB␣ in mononuclear cells from patients with type 1 diabetes. This was associated with increased transcription of NF-Bp65. A comparable increase in NF-Bp65 antigen and mRNA was also observed in vascular endothelial cells of diabetic rats. As a mechanism, we propose that binding of ligands such as advanced glycosylation end products (AGEs), members of the S100 family, or amyloid-␤ peptide ( T issue culture models of cellular activation provide easily accessible systems for detailed analysis of mechanisms potentially underlying the pathogenesis of human disease. However, the time course of such in vitro models is usually significantly abbreviated, limited to hours to days, compared with the pace of disorders under study in vivo. This indicates the importance of seeking out mechanisms in cell culture that might bridge the gap that accounts for the chronicity of cellular perturbation observed in the intact organism.The transcription factor nuclear factor-B (NF-B) has been proposed as a critical bridge between oxidant stress and gene expression (1-8). Exposure of cells to inflammatory, infectious, or other stressful stimuli results in rapid phosphorylation and degradation of IB␣ and the subsequent release and translocation of NF-B into the nucleus (1-11). This mechanism ensures quick and finely tuned cellular responses in the absence of de novo protein synthesis. Because transcription of IB␣ is positively autoregulated by NF-B (9 -11), activation of NF-B is usually self-terminated within minutes to hours (1-11). Such a scenario lends itself to analysis by short-term in vitro studies in which stimulus-induced responses are transient and the system returns to the baseline state over hours. Consequently, induction of NF-B and enhanced transcription of its target genes in vitro have been studied mainly in the setting of acute cellular responses.Reactive oxygen intermediates are generated by processes that occur over seconds. However, increasing evidence suggests a role for oxidative stress in chronic degenerative diseases such as atherosclerosis (1,6,12,13), diabetes (14 -16), and Alzheimer's disease (17)(18)(19). This indicates the relevance of signal transduction systems such as NF-B, which are capable of transforming the appearance and disappearance of short-lived oxygen free radicals into more sustained signals for cellular activation

Nervous system development and plasticity require regulation of cell proliferation, survival, neurite outgrowth and synapse formation by specific extracellular factors. The EF-hand protein S100B is highly expressed in human brain. In the extracellular space, it promotes neurite extension and neuron survival via the receptor RAGE (receptor for advanced glycation end products). The X-ray structure of human Ca 2 þ -loaded S100B was determined at 1.9 Å resolution. The structure revealed an octameric architecture of four homodimeric units arranged as two tetramers in a tight array. The presence of multimeric forms in human brain extracts was confirmed by size-exclusion experiments. Recombinant tetrameric, hexameric and octameric S100B were purified from Escherichia coli and characterised. Binding studies show that tetrameric S100B binds RAGE with higher affinity than dimeric S100B. Analytical ultracentrifugation studies imply that S100B tetramer binds two RAGE molecules via the V-domain. In line with these experiments, S100B tetramer caused stronger activation of cell growth than S100B dimer and promoted cell survival. The structural and the binding data suggest that tetrameric S100B triggers RAGE activation by receptor dimerisation.

Prognosis for patients suffering from malignant glioma has not substantially improved. Specific immunotherapy as a novel treatment concept critically depends on target antigens, which are highly overexpressed in the majority of gliomas, but the number of such antigens is still very limited. SOX2 was identified by screening an expression database for transcripts that are overexpressed in malignant glioma, but display minimal expression in normal tissues. Expression of SOX2 mRNA was further investigated in tumour and normal tissues by real-time PCR. Compared to cDNA from pooled normal brain, SOX2 was overexpressed in almost all (9 out of 10) malignant glioma samples, whereas expression in other, non-malignant tissues was almost negligible. SOX2 protein expression in glioma cell lines and tumour tissues was verified by Western blot and immunofluorescence. Immunohistochemistry demonstrated SOX2 protein expression in all malignant glioma tissues investigated ranging from 6 to 66% stained tumour cells. Human leucocyte antigen-A*0201-restricted SOX2-derived peptides were tested for the activation of glioma-reactive CD8 þ cytotoxic T lymphocytes (CTLs). Specific CTLs were raised against the peptide TLMKKDKYTL and were capable of lysing glioma cells. The abundant and glioma-restricted overexpression of SOX2 and the generation of SOX2-specific and tumour-reactive CTLs may recommend this antigen as target for T-cell-based immunotherapy of glioma.

The receptor for advanced glycation end-products (RAGE) is a transmembrane receptor of the immunoglobulin superfamily. Several ligands binding to RAGE have been identified, including amphoterin. Experimental studies have given rise to the discussion that RAGE and its interaction with amphoterin contribute to tumour growth and metastasis. However, none of the studies considered a differential transcription profile in cancer that might change the interpretation of the study results when comparing RAGE in tumours with histologically normal tissues. Here we show that RAGE is strongly reduced at the mRNA and even more so at the protein level in non-small cell lung carcinomas compared with normal lung tissues. Down-regulation of RAGE correlates with higher tumour (TNM) stages but does not depend on the histological subtypes, squamous cell lung carcinoma and adenocarcinoma. Subsequent overexpression of full-length human RAGE in lung cancer cells (NCI-H358) showed diminished tumour growth under some conditions. While proliferation of RAGE-expressing cells was less than that of cells expressing the cytoplasmic domain deletion mutant DeltacytoRAGE or mock-transfected NCI-H358 in monolayer cultures, RAGE cells also formed smaller tumours in spheroid cultures and in vivo in athymic mice compared with DeltacytoRAGE cells. Moreover, we observed a more epithelial growth of RAGE-expressing, but also of DeltacytoRAGE-expressing, cells on collagen layers, whereas mock NCI-H358 cells kept their tumour morphology. This observation was supported by immunofluorescence analyses demonstrating that RAGE preferentially localizes at intercellular contact sites, independent of expression of the cytoplasmic domain. Thus, down-regulation of RAGE may be considered as a critical step in tissue reorganization and the formation of lung tumours.

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Dendritic cells (DCs) are characterized by their unique capacity for primary T cell activation, providing the opportunity for DC-based cancer vaccination protocols. Novel findings reveal that besides their role as potent inducers of tumor-specific T cells, human DCs display additional antitumor effects. Most of these data were obtained with monocyte-derived DCs, whereas studies investigating native blood DCs are limited. In the present study, we analyze the tumoricidal capacity of M-DC8+ DCs, which represent a major subpopulation of human blood DCs. We demonstrate that IFN-γ-stimulated M-DC8+ DCs lyse different tumor cell lines but not normal cells. In addition, we show that tumor cells markedly enhance the production of TNF-α by M-DC8+ DCs via cell-to-cell contact and that this molecule essentially contributes to the killing activity of M-DC8+ DCs. Furthermore, we illustrate the ability of M-DC8+ DCs to promote proliferation, IFN-γ production, and tumor-directed cytotoxicity of NK cells. The M-DC8+ DC-mediated enhancement of the tumoricidal potential of NK cells is mainly dependent on cell-to-cell contact. These results reveal that, in addition to their crucial role in activating tumor-specific T cells, blood DCs exhibit direct tumor cell killing and enhance the tumoricidal activity of NK cells. These findings point to the pivotal role of DCs in triggering innate and adaptive immune responses against tumors.

In this study we show that embryonic neurite growth-promoting protein amphoterin binds to carboxylated N-glycans previously identified on mammalian endothelial cells. Since amphoterin is a ligand for the receptor for advanced glycation end products (RAGE), and the ligand-binding V-domain of the receptor contains two potential N-glycosylation sites, we hypothesized that N-glycans on RAGE may mediate its interactions with amphoterin. In support of this, anti-carboxylate antibody mAbGB3.1 immunoprecipitates bovine RAGE, and PNGase F treatment reduces its molecular mass by 4.5 kDa, suggesting that the native receptor is a glycoprotein. The binding potential of amphoterin to RAGE decreases significantly in presence of soluble carboxylated glycans or when the receptor is deglycosylated. Oligosaccharide analysis shows that RAGE contains complex type anionic N-glycans with non-sialic acid carboxylate groups, but not the HNK-1 (3-sulfoglucuronyl b1-3 galactoside) epitope. Consistent with the functional localization of RAGE and amphoterin at the leading edges of developing neurons, mAbGB3.1 stains axons and growth cones of mouse embryonic cortical neurons, and inhibits neurite outgrowth on amphoterin matrix. The carboxylated glycans themselves promote neurite outgrowth in embryonic neurons and RAGE-transfected neuroblastoma cells. This outgrowth requires full-length, signalling-competent RAGE, as cells expressing cytoplasmic domain-deleted RAGE are unresponsive. These results indicate that carboxylated N-glycans on RAGE play an important functional role in amphoterin-RAGE-mediated signalling.

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