Background:Glioma stem-like cell (GSC) properties are responsible for gliomagenesis and recurrence. GSCs are invasive but its mechanism remains to be elucidated. Here, we attempted to identify the molecules that promote invasion in GSCs.Methods:Neurospheres and CD133+ cells were collected from glioblastoma (GBM) specimens and glioma cell lines by sphere-formation method and magnetic affinity cell sorting, respectively. Differential expression of gene candidates, its role in invasion and its signaling pathway were evaluated in glioma cell lines.Results:Neurospheres from surgical specimens attached to fibronectin and laminin, the receptors of which belong to the integrin family. Integrin α3 was overexpressed in CD133+ cells compared with CD133− cells in all the glioma cell lines (4 out of 4). Immunohistochemistry demonstrated the localisation of integrin α3 in GBM cells, including invading cells, and in the tumour cells around the vessels, which is believed to be a stem cell niche. The expression of integrin α3 was correlated with migration and invasion. The invasion activity of glioma cells was linked to the phosphorylation of extracellular signal–regulated kinase (ERK) 1/2.Conclusion:Our results suggest that integrin α3 contributes to the invasive nature of GSCs via ERK1/2, which renders integrin α3 a prime candidate for anti-invasion therapy for GBM.
Abstract-The stainless steel cannula inserting method was used to examine the effects of methysergide on 5-hydroxytryptamine (5-HT) and norepinephrine induced vasoconstriction in the isolated internal carotid artery of the dog. 5-HT, at a dose of 0.3 /cg, induced a marked increase in perfusion pressure, usually over 100 mm Hg. On the other hand, norepinephrine produced a relatively small increase in perfusion pressure (20-40 mm Hg) at a large dose of 10 /cg. Methysergide inhibited 5-HT-induced vasconstriction.
The structural requirements for the interaction of asparagine-linked oligosaccharide moieties of glycoproteins with wheat germ agglutinin (WGA) were investigated by using affinity chromatography on a WGA-Sepharose column. So-called hybrid-type glycopeptides obtained from ovalbumin [Yamashita, K., Tachibana, Y., & Kobata, A. (1978) J. Biol. Chem. 253, 3862--3869] were found to have high affinity for WGA--Sepharose, whereas high mannose-type and complex-type glycopeptides were shown to have low affinity. The elution profiles of various glycopeptides modified by glycosidase treatment, Smith periodate degradation, acetolysis, and hydrazinolysis showed that the GlcNAcbeta 1--4Manbeta 1--4GlcNAc beta 1--4GlcNAc-Asn structure was essential for the binding of glycopeptides to a WGA-Sepharose column. Thus, it was revealed that both the N,N'-diacetylchitobiose moiety and the beta-N-acetylglucosaminyl residue linked to C-4 of the beta-linked mannose residue contributed to the interaction of the glycopeptide with WGA-Sepharose. The substitution at C-6 of the innermost beta-N-acetylglucosaminyl residue by an alpha-fucosyl residue or at C-6 of the beta-linked mannose residue by another mannose residue in the above structure reduced the affinity of glycopeptides for the column.
c Staphylococcal superantigen-like proteins (SSLs) are a family of exoproteins sharing structural similarity with superantigens, but no superantigenic activity. Corresponding host target proteins or receptors against a portion of SSLs in the family have been identified. In this study, we show that SSL3 specifically binds to Toll-like receptor 2 (TLR2) and inhibits the stimulation of macrophages by TLR2 ligands. An approximately 100-kDa protein was recovered by using recombinant His-tagged SSL3-conjugated Sepharose from the lysate of porcine spleen, and the protein was identified as porcine TLR2 by peptide mass fingerprinting analysis. The SSL3-conjugated Sepharose recovered human and mouse TLR2 but not TLR4 from human neutrophils and mouse macrophage RAW 264.7 cells, as well as a recombinant TLR2 extracellular domain chimera protein. The production levels of interleukin 12 (IL-12) from mouse macrophages treated with heat-killed Staphylococcus aureus and of tumor necrosis factor alpha (TNF-␣) from RAW 264.7 cells induced by peptidoglycan or lipopeptide TLR2 ligands were strongly suppressed in the presence of SSL3. The mutation of consensus sialic acid-containing glycan-binding residues in SSL3 did not abrogate the binding ability to TLR2 or inhibitory activity on TLR2, indicating that the interaction of SSL3 with TLR2 was independent of the sialic acid-containing glycan-binding residues. These findings demonstrate that SSL3 is able to bind the extracellular domain of TLR2 and interfere with TLR2 function. The present study provides a novel mechanism of SSL3 in immune evasion of S. aureus via interfering with its recognition by innate immune cells.
p51/p63, a member of the tumor suppressor p53 gene family, is crucial for skin development. We describe here identification of ITGA3 encoding integrin ␣ 3 as a target of its trans-activating function, proposing that p51/p63 allows epidermal stem cells to express laminin receptor ␣ 3  1 for anchorage to the basement membrane. When activated by genotoxic stress or overexpressed ectopically in non-adherent cells, p51/p63 transduced a phenotype to attach to extracellular matrices, which was accompanied by expression of ITGA3. Motifs matching the p53-binding consensus sequence were located in a scattered form in intron 1 of human ITGA3, and served as p51/p63-responsive elements in reporter assays. In addition to the trans-activating ability of the TA isoform, we detected a positive effect of the ⌬N isoform on ITGA3. The high level ␣ 3 production in human keratinocyte stem cells diminished upon elimination of p51/p63 by small interfering RNA or by Ca 2؉ -induced differentiation. Furthermore, a chromatin immunoprecipitation experiment indicated a physical interaction of p51/p63 with intron 1 of ITGA3. This study provides a molecular basis for the standing hypothesis that p51/p63 is essential for epidermal-mesenchymal interactions.
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