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  • 1
    Keywords: brain ; SPECTRA ; CELLS ; IN-VITRO ; tumor ; AGENTS ; CELL ; human ; MODEL ; VITRO ; DISEASE ; TUMORS ; MICE ; ACTIVATION ; LIGAND ; BINDING ; SUPPRESSION ; MOLECULE ; RECOGNITION ; ACID ; GLYCOPROTEIN ; PATHOGENESIS ; DOSE-RESPONSE ; LIGANDS ; EPITHELIAL-CELLS ; specificity ; DMBT1 ; AGENT ; AGGREGATION ; MOTIF ; PRODUCTS ; brain tumor ; BRAIN-TUMORS ; COLITIS ; interaction ; SODIUM ; pattern recognition ; structure ; brain tumors ; LPS ; Genetic ; genetic study ; BRAIN-TUMOR ; A
    Abstract: Deleted in malignant brain tumors 1 (DMBT1) is a secreted glycoprotein displaying a broad bacterial-binding spectrum. Recent functional and genetic studies linked DMBT1 to the suppression of LPS-induced TLR4-mediated NF-kappaB activation and to the pathogenesis of Crohn's disease. Here, we aimed at unraveling the molecular basis of its function in mucosal protection and of its broad pathogen-binding specificity. We report that DMBT1 directly interacts with dextran sulfate sodium (DSS) and carrageenan, a structurally similar sulfated polysaccharide, which is used as a texturizer and thickener in human dietary products. However, binding of DMBT1 does not reduce the cytotoxic effects of these agents to intestinal epithelial cells in vitro. DSS and carrageenan compete for DMBT1-mediated bacterial aggregation via interaction with its bacterial-recognition motif. Competition and ELISA studies identify poly-sulfated and poly-phosphorylated structures as ligands for this recognition motif, such as heparansulfate, LPS, and lipoteichoic acid. Dose-response studies in Dmbt1(-/-) and Dmbt1(+/+) mice utilizing the DSS-induced colitis model demonstrate a differential response only to low but not to high DSS doses. We propose that DMBT1 functions as pattern-recognition molecule for poly-sulfated and poly-phosphorylated ligands providing a molecular basis for its broad bacterial-binding specificity and its inhibitory effects on LPS-induced TLR4-mediated NF-kappaB activation.
    Type of Publication: Journal article published
    PubMed ID: 19189310
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  • 2
    Keywords: brain ; CANCER ; CELLS ; EXPRESSION ; tumor ; TUMOR-CELLS ; carcinoma ; CELL ; Germany ; human ; IN-VIVO ; LUNG ; VIVO ; COMMON ; lung cancer ; LUNG-CANCER ; NEW-YORK ; GENE ; GENOME ; EPITHELIA ; TISSUE ; TUMORS ; MICE ; INDUCTION ; TISSUES ; DOWN-REGULATION ; BREAST ; breast cancer ; BREAST-CANCER ; MOUSE ; IN-SITU ; UP-REGULATION ; MUTATION ; EXTRACELLULAR-MATRIX ; MUTATIONS ; SUPERFAMILY ; EPITHELIAL-CELLS ; GLANDS ; BEHAVIOR ; LUNG-CARCINOMA ; TERMINAL DIFFERENTIATION ; galectin-3 ; MALIGNANT BRAIN-TUMORS ; SCAVENGER RECEPTOR ; MATRIX ; AGGLUTININ
    Abstract: Deleted in malignant brain tumors 1 (DIMBT1) has been proposed as a candidate tumor suppressor for brain and epithelial cancer. Initial studies suggested loss of expression rather than mutation as the predominant mode of DMBT1 inactivation. However, in situ studies in lung cancer demonstrated highly sophisticated changes of DMBT1 expression and localization, pointing to a chronological order of events. Here we report on the investigation of DMBT1 in breast cancer in order to test whether these principles might also be attributable to other tumor types. Comprehensive mutational analyses did not uncover unambiguous inactivating DMBT1 mutations in breast cancer. Expression analyses in the human and mouse mammary glands pointed to the necessity of DMBT1 induction. While age-dependent and hormonal effects could be ruled out, 9 of 10 mice showed induction of Dmbt1 expression after administration of the carcinogen 7,12-dimethybenz(alpha)anthracene prior to the onset of tumorigenesis or other histopathological changes. DMBT1 displayed significant up-regulation in human tumor-flanking tissues compared to in normal breast tissues (P 〈 0.05). However, the breast tumor cells displayed a switch from lumenal secretion to secretion to the extracellular matrix and a significant down-regulation compared to that in matched normal flanking tissues (P 〈 0.01). We concluded that loss of expression also is the predominant mode of DMBT1 inactivation in breast cancer. The dynamic behavior of DMBT1 in lung carcinoma is fully reflected in breast cancer, which suggests that this behavior might be common to tumor types arising from monolayered epithelia. (C) 2003 Wiley-Liss, Inc
    Type of Publication: Journal article published
    PubMed ID: 14732920
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  • 3
    Keywords: brain ; RECEPTOR ; CELLS ; EXPRESSION ; tumor ; CELL ; Germany ; IN-VIVO ; VIVO ; DISEASE ; RISK ; GENOME ; HYBRIDIZATION ; PROTEIN ; SAMPLE ; TISSUE ; TUMORS ; MICE ; PATIENT ; DOMAIN ; GENETIC POLYMORPHISMS ; TISSUES ; polymorphism ; POLYMORPHISMS ; SUSCEPTIBILITY ; DELETION ; IN-SITU ; prevention ; immunohistochemistry ; UP-REGULATION ; NUMBER ; PATHOGENESIS ; DISPLAY ; HUMAN GENOME ; SURFACE ; EPITHELIAL-CELLS ; genetic polymorphism ; NORMAL TISSUE ; CHAIN-REACTION ; SMALL-INTESTINE ; ULCERATIVE-COLITIS ; TERMINAL DIFFERENTIATION ; inflammation ; SALIVARY AGGLUTININ ; SURFACTANT PROTEIN-D ; INFLAMMATORY-BOWEL-DISEASE ; MALIGNANT BRAIN-TUMORS ; SCAVENGER RECEPTOR ; in situ hybridization ; CHAIN ; BRAIN-TUMORS ; pathogen ; VARIANT ; ALLELE ; inflammatory bowel disease ; LEVEL ; methods ; SUBTYPES ; SULFATE ; USA ; function ; INCREASED RISK ; odds ratio ; in vivo ; case control ; quantitative ; MUCOSAL ; EXONS ; CRP-DUCTIN ; DEXTRAN SULFATE SODIUM
    Abstract: Background & Aims: Impaired mucosal. defense plays an important role in the pathogenesis of Crohn's disease (CD), one of the main subtypes of inflammatory bowel disease (IBD). Deleted in malignant brain tumors 1(DMBT1) is a secreted scavenger receptor cysteine-rich protein with predominant expression in. the intestine and has been proposed to exert possible functions in regenerative processes and pathogen defense. Here, we aimed at analyzing the role of DMBT1 in IBD. Methods: We studied DMBT1 expression in IBD and normal tissues by quantitative reverse transcription-polymerase chain reaction, immunohistochemistry, and mRNA in situ hybridization. Genetic polymorphisms within DMBT1 were analyzed in an Italian IBD case-control sample. Dmbt1(-/-) mice were generated, characterized, and analyzed for their susceptibility to dextran sulfate sodium-induced colitis. Results: DMBT1 levels correlate with disease activity in inflamed IBD tissues. A highly significant fraction of the patients with IBD displayed up-regulation of DMBT1 specifically in the intestinal epithelial surface cells and Paneth cells. A deletion allele of DMBT1 with a reduced: number of scavenger receptor cysteine-rich domain coding exons is associated with an increased risk of CD (P =.00056; odds ratio, 1.75) but not for ulcerative colitis. Dmbt1(-/-) mice display enhanced susceptibility to dextran sulfate sodium-induced colitis and elevated Tnf, Il6, and Nod2 expression levels during inflammation. Conclusions: DMBT1 may play a role in intestinal mucosal protection and prevention of inflammation. Impaired DMBT1 function may contribute to the pathogenesis of CD
    Type of Publication: Journal article published
    PubMed ID: 17983803
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  • 4
    Keywords: RECEPTOR ; CANCER ; CELLS ; EXPRESSION ; IN-VITRO ; tumor ; SUPPORT ; SYSTEM ; GENE ; PROTEIN ; PROTEINS ; DIFFERENTIATION ; TUMORS ; LINES ; COMPLEX ; COMPLEXES ; DOMAIN ; INDUCTION ; mechanisms ; SKIN ; MUTATION ; HETEROZYGOSITY ; MELANOMA ; CARCINOMA-CELLS ; EXCHANGE ; EPITHELIAL-CELLS ; squamous cell carcinoma ; epidermis ; TERMINAL DIFFERENTIATION ; DMBT1 ; SALIVARY AGGLUTININ ; basal cell carcinoma ; galectin-3 ; MALIGNANT BRAIN-TUMORS
    Abstract: DMBT1 and galectin-3 are potential interacting proteins with presumably complex roles in tumorigenesis. While at present a variety of mechanisms are discussed for DMBT1 and its participation in cancer, galectin-3 is commonly known to exert tumor-promoting effects. However, in vitro studies in a rodent system have suggested that DMBT1/galectin-3 interaction in the ECM triggers epithelial differentiation, which would point to tumor-suppressive properties. To improve the understanding of DMBT1/galectin-3 action in cancer, we carried out studies in skin cancer of different origins. Mutational analyses of DMBT1 identified a missense mutation in 1 of 13 melanoma cell lines. It led to an exchange of an evolutionary conserved proline residue for serine and located within the second CUB domain of DMBT1. Immunohistochemical analyses demonstrated absence of DMBT1/galectin-3 expression from melanocytes but induction of DMBT1 expression in 1 of 8 nevi and 1 of 11 melanomas and of galectin-3 expression in 3 of 8 nevi and 4 of 8 melanomas. These data suggest that DMBT1 and galectin-3 are unlikely to act as classical tumor suppressors in melanomas. DMBT1 and galectin-3 appear to be secreted to the ECM by epithelial cells within the epidermis and the hair follicle. Compared to the flanking normal epidermis, skin tumors of epithelial origin frequently displayed downregulation of DMBT1 (18 of 19 cases) and galectin-3 (12 of 12 cases). Thus, loss of DMBT1/ galectin- 3 expression may play a role in the genesis of epithelial skin cancer. This would support the view that galectin-3 can exert tumor-suppressive effects in certain scenarios, and DMBT1/galectin-3-mediated differentiation represents a candidate mechanism for this effect. (C) 2003 Wiley-Liss, Inc
    Type of Publication: Journal article published
    PubMed ID: 12673672
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