| 1. |
- Persson, Andrea, et al.
(författare)
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Xyloside-primed chondroitin sulfate/dermatan sulfate from breast carcinoma cells with a defined disaccharide composition has cytotoxic effects in vitro
- 2016
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 291:28, s. 14871-14882
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Tidskriftsartikel (refereegranskat)abstract
- We have previously reported that the xyloside 2-(6-hydroxynaphthyl) β-D-xylopyranoside (XylNapOH), in contrast to 2-naphthyl β-D-xylopyranoside (XylNap), specifically reduces tumor growth both in vitro and in vivo. Although there are indications that this could be mediated by the xyloside-primed glycosaminoglycans (GAGs) and that these differ in composition depending on xyloside and cell type, detailed knowledge regarding a structure-function relationship is lacking. In this study, we isolated XylNapOH- and XylNap-primed GAGs from a breast carcinoma cell line, HCC70, and a breast fibroblast cell line, CCD-1095Sk, and demonstrated that both XylNapOH- and XylNap-primed chondroitin sulfate/dermatan sulfate (CS/DS) GAGs derived from HCC70 cells had a cytotoxic effect on HCC70 cells and CCD-1095Sk cells. The cytotoxic effect appeared to be mediated by induction of apoptosis and was inhibited in a concentration-dependent manner by the XylNap-primed heparan sulfate (HS) GAGs. In contrast, neither the CS/DS nor the HS derived from CCD-1095Sk cells primed on XylNapOH or XylNap had any effect on the growth of HCC70 cells or CCD-105Sk cells. These observations were related to the disaccharide composition of the XylNapOH- and XylNap-primed GAGs, which differed considerably between the two cell lines, but was similar when the GAGs were derived from the same cell line. To our knowledge, this is the first report on cytotoxic effects mediated by CS/DS.
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| 2. |
- Siegbahn, Anna, et al.
(författare)
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Exploration of the active site of β4GalT7: modifications of the aglycon of aromatic xylosides.
- 2015
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Ingår i: Organic and Biomolecular Chemistry. - : Royal Society of Chemistry (RSC). - 1477-0539 .- 1477-0520. ; 13:11, s. 3351-3362
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Tidskriftsartikel (refereegranskat)abstract
- Proteoglycans (PGs) are macromolecules that consist of long linear polysaccharides, glycosaminoglycan (GAG) chains, covalently attached to a core protein by the carbohydrate xylose. The biosynthesis of GAG chains is initiated by xylosylation of the core protein followed by galactosylation by the galactosyltransferase β4GalT7. Some β-d-xylosides, such as 2-naphthyl β-d-xylopyranoside, can induce GAG synthesis by serving as acceptor substrates for β4GalT7 and by that also compete with the GAG synthesis on core proteins. Here we present structure-activity relationships for β4GalT7 and xylosides with modifications of the aromatic aglycon, using enzymatic assays, cell studies, and molecular docking simulations. The results show that the aglycons reside on the outside of the active site of the enzyme and that quite bulky aglycons are accepted. By separating the aromatic aglycon from the xylose moiety by linkers, a trend towards increased galactosylation with increased linker length is observed. The galactosylation is influenced by the identity and position of substituents in the aromatic framework, and generally, only xylosides with β-glycosidic linkages function as good substrates for β4GalT7. We also show that the galactosylation ability of a xyloside is increased by replacing the anomeric oxygen with sulfur, but decreased by replacing it with carbon. Finally, we propose that reaction kinetics of galactosylation by β4GalT7 is dependent on subtle differences in orientation of the xylose moiety.
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| 3. |
- Aili, Ulrika, et al.
(författare)
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Antiproliferative effects of peracetylated naphthoxylosides.
- 2009
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Ingår i: Bioorganic & Medicinal Chemistry Letters. - : Elsevier BV. - 0960-894X. ; 19, s. 1763-1766
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Tidskriftsartikel (refereegranskat)abstract
- The antiproliferative activity, and the capability of priming of glycosaminoglycan chains, of two series of peracetylated mono- and bis-xylosylated dihydroxynaphthalenes have been investigated for normal HFL-1 cells, as well as transformed T24 cells, and compared to the unprotected analogs. Our data show increased antiproliferative activity upon peracetylation, but a loss of selectivity towards T24 cells.
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| 4. |
- Cheng, Fang, et al.
(författare)
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APP/APLP2 expression is required to initiate endosome-nucleus-autophagosome trafficking of glypican-1-derived heparan sulfate.
- 2014
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 289:30, s. 20871-20878
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Tidskriftsartikel (refereegranskat)abstract
- Anhydromannose (anMan)-containing heparan sulfate (HS) derived from the proteoglycan glypican-1 (Gpc-1) is generated in endosomes by an endogenously or ascorbate induced SNO-catalyzed reaction. Processing of the amyloid precursor protein (APP) and APP-like protein 2 (APLP2) by β- and γ-secretases into amyloid beta (Aβ) and Aβ-like peptides also takes place in these compartments. Moreover, anMan-containing HS suppresses the formation of toxic Aβ assemblies in vitro. We show by using deconvolution immunofluorescence microscopy with an anMan-specific monoclonal antibody as well as 35S-labeling experiment that expression of APP/APLP2 is required for ascorbate-induced transport of HS from endosomes to the nucleus. Nuclear translocation was observed in wild-type mouse embryonic fibroblasts (Wt-MEF), Tg2576 MEF and N2a neuroblastoma cells but not in APP-/- and APLP2-/- MEF. Transfection of APP-/- cells with a vector encoding APP restored nuclear import of anMan-containing HS. In Wt-MEF and N2a neuroblastoma cells exposed to β- or γ-secretase inhibitors, nuclear translocation was greatly impeded, suggesting involvement of APP/APLP2 degradation products. In Tg2576 MEF, the β-inhibitor blocked transport but the γ- inhibitor did not. During chase in ascorbate-free medium, anMan-containing HS disappeared from the nuclei of Wt-MEF. Confocal immunofluorescence microscopy showed that they appeared in acidic, LC3-positive vesicles in keeping with an autophagosomal location. There was increased accumulation of anMan-containing HS in nuclei and cytosolic vesicles upon treatment with chloroquine indicating that HS was degraded in lysosomes. Manipulations of APP expression and processing may have deleterious effects upon HS function in the nucleus.
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| 5. |
- Cheng, Fang, et al.
(författare)
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Suppression of amyloid beta a11-immunoreactivity by vitamin C: possible role of heparan sulfate oligosaccharides derived from glypican-1 by ascorbate-induced, no-catalyzed degradation.
- 2011
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 286:31, s. 27559-27572
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid beta is generated from the copper- and heparan sulfate (HS)-binding amyloid precursor protein (APP) by proteolytic processing. APP supports S-nitrosylation of the HS-proteoglycan glypican-1 (Gpc-1). In the presence of ascorbate there is NO-catalyzed release of anhydromannose (anMan)-containing oligosaccharides from Gpc-1-SNO. We have investigated whether these oligosaccharides interact with amyolid beta during APP processing and plaque formation. anMan-Immunoreactivity was detected in amyloid plaques of Alzheimer (AD) and APP transgenic (Tg2576) mouse brains by immunofluorescence microscopy. APP/APP degradation products detected by antibodies to the C-terminus of APP, but not amyolid beta oligomers detected by the anti-amyloid beta A11 antibody, colocalized with anMan-immunoreactivity in Tg2576 fibroblasts. A 50-55-kDa anionic, SDS-stable, anMan- and amyloid beta-immunoreactive species was obtained from Tg2576 fibroblasts using immunoprecipitation with anti-APP (C-terminal). anMan-Containing HS oligo- and disaccharide preparations modulated or suppressed A11-immunoreactivity and oligomerization of amyloid beta 42 peptide in an in vitro assay. A11 immunoreactivity increased in Tg2576 fibroblasts when Gpc-1 autoprocessing was inhibited by U18666A, and decreased when Gpc-1 autoprocessing was stimulated by ascorbate. Neither overexpression of Gpc-1 in Tg2576 fibroblasts nor addition of copper ion and NO-donor to hippocampal slices from 3xTg-AD mice affected A11 immunoreactivity levels. However, A11 immunoreactivity was greatly suppressed by the subsequent addition of ascorbate. We speculate that temporary interaction between the amyolid beta domain and small, anMan-containing oligosaccharides may preclude formation of toxic amyloid beta oligomers. A portion of the oligosaccharides co-secrete with the amyloid beta peptides and are deposited in plaques. These results support the notion that inadequate supply of vitamin C could contribute to late onset AD in humans.
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| 6. |
- Ding, Kan, et al.
(författare)
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Modulations of glypican-1 heparan sulfate structure by inhibition of endogenous polyamine synthesis. Mapping of spermine-binding sites and heparanase, heparin lyase, and nitric oxide/nitrite cleavage sites
- 2001
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 276:50, s. 46779-46791
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Tidskriftsartikel (refereegranskat)abstract
- Cell surface heparan sulfate proteoglycans facilitate uptake of growth-promoting polyamines (Belting, M., Persson, S., and Fransson, L.-A. (1999) Biochem. J. 338, 317-323; Belting, M., Borsig, L., Fuster, M. M., Brown, J. R., Persson, L., Fransson, L.-A., and Esko, J. D. (2001) Proc. Natl. Acad. Sci. U. S. A., in press). Here, we have analyzed the effect of polyamine deprivation on the structure and polyamine affinity of the heparan sulfate chains in various glypican-1 glycoforms synthesized by a transformed cell line (ECV 304). Heparan sulfate chains of glypican-1 were either cleaved with heparanase at sites embracing the highly modified regions or with nitrite at N-unsubstituted glucosamine residues. The products were separated and further degraded by heparin lyase to identify sulfated iduronic acid. Polyamine affinity was assessed by chromatography on agarose substituted with the polyamine spermine. In heparan sulfate made by cells with undisturbed endogenous polyamine synthesis, free amino groups were restricted to the unmodified, unsulfated segments, especially near the core protein. Spermine high affinity binding sites were located to the modified and highly sulfated segments that were released by heparanase. In cells with up-regulated polyamine uptake, heparan sulfate contained an increased number of clustered N-unsubstituted glucosamines and sulfated iduronic acid residues. This resulted in a greater number of NO/nitrite-sensitive cleavage sites near the potential spermine-binding sites. Endogenous degradation by heparanase and NO-derived nitrite in polyamine-deprived cells generated a separate pool of heparan sulfate oligosaccharides with an exceptionally high affinity for spermine. Spermine uptake in polyamine-deprived cells was reduced when NO/nitrite-generated degradation of heparan sulfate was inhibited. The results suggest a functional interplay between glypican recycling, NO/nitrite-generated heparan sulfate degradation, and polyamine uptake.
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| 7. |
- Ding, Kan, et al.
(författare)
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N-unsubstituted glucosamine in heparan sulfate of recycling glypican-1 from suramin-treated and nitrite-deprived endothelial cells. mapping of nitric oxide/nitrite-susceptible glucosamine residues to clustered sites near the core protein
- 2001
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 276:6, s. 3885-3894
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Tidskriftsartikel (refereegranskat)abstract
- We have analyzed the content of N-unsubstituted glucosamine in heparan sulfate from glypican-1 synthesized by endothelial cells during inhibition of (a) intracellular progression by brefeldin A, (b) heparan sulfate degradation by suramin, and/or (c) endogenous nitrite formation. Glypican-1 from brefeldin A-treated cells carried heparan sulfate chains that were extensively degraded by nitrous acid at pH 3.9, indicating the presence of glucosamines with free amino groups. Chains with such residues were rare in glypican-1 isolated from unperturbed cells and from cells treated with suramin and, surprisingly, when nitrite-deprived. However, when nitrite-deprived cells were simultaneously treated with suramin, such glucosamine residues were more prevalent. To locate these residues, chains were first cleaved at linkages to sulfated l-iduronic acid by heparin lyase and released fragments were separated from core protein carrying heparan sulfate stubs. These stubs were then cleaved off at sites linking N-substituted glucosamines to d-glucuronic acid. These fragments were extensively degraded by nitrous acid at pH 3.9. When purified proteoglycan isolated from brefeldin A-treated cells was incubated with intact cells, endoheparanase-catalyzed degradation generated a core protein with heparan sulfate stubs that were similarly sensitive to nitrous acid. We conclude that there is a concentration of N-unsubstituted glucosamines to the reducing side of the endoheparanase cleavage site in the transition region between unmodified and modified chain segments near the linkage region to the protein. Both sites as well as the heparin lyase-sensitive sites seem to be in close proximity to one another.
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| 8. |
- Jacobsson, Mårten, et al.
(författare)
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Effects of oxygen-sulfur substitution on glycosaminoglycan-priming naphthoxylosides.
- 2007
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Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896. ; 15:15, s. 5283-5299
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Tidskriftsartikel (refereegranskat)abstract
- Three series of sulfur-containing analogs to the selectively antiproliferative 2-(6-hydroxynaphthyl) β-d-xylopyranoside were synthesized and their biological properties investigated. A short, general route to hydroxynaphthyl disulfides from dihydroxynaphthalenes was developed to utilize the disulfide bond as a sulfur-selective protecting group to enable the orthogonal protection of hydroxyls and thiols. The results indicate that hydrophobic, uncharged oxygen–sulfur substituted naphthoxylosides are taken up by cells and initiate priming of GAG chains to a greater extent compared to the oxygen analogs. No correlation between priming ability and antiproliferative activity was observed.
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| 9. |
- Jacobsson, Mårten, et al.
(författare)
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Selective antiproliferative activity of hydroxynaphthyl-beta-D-xylosides
- 2006
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 1520-4804 .- 0022-2623. ; 49:6, s. 1932-1938
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Tidskriftsartikel (refereegranskat)abstract
- The antiproliferative activity of the 14 isomeric monoxylosylated dihydroxynaphthalenes has been tested in vitro toward normal HFL-1 and 3T3 A31 cells as well as transformed T24 and 3T3 SV40 cells. The antiproliferative effect toward HFL-1 cells was correlated with the polarity of the compounds. However, in the case of transformed T24 cells, some compounds showed a clearly different behavior resulting in a selective antiproliferative effect. No such correlation was found for normal 3T3 A31 or virus transformed 3T3 SV40 cells, nor for the free aglycon. These results suggest that the antiproliferative activity shown by naphthoxylosides is diverse in different cell lines and dependent on the nature of the aglycon. The anti proliferative effect of 2- (6-hydroxynaphthyl)-beta-D-xylopyranoside, in contrast to inactive 2-naphthyl-beta-D-xylopyranoside, on T24 cells was accompanied by increased apoptosis as indicated by a TUNEL assay.
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| 10. |
- Johnsson, Richard, et al.
(författare)
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Evaluation of fluorescently labeled xylopyranosides as probes for proteoglycan biosynthesis
- 2007
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Ingår i: Bioorganic & Medicinal Chemistry Letters. - : Elsevier BV. - 0960-894X. ; 17:8, s. 2338-2341
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Tidskriftsartikel (refereegranskat)abstract
- A new fluorescent analog to the antiproliferative 2-(6-hydroxynaphthyl)-beta-D-xylopyranoside has been synthesized and tested on a T24 cell line. The new analog was efficiently uptaken by the T24 cells but did not initiate priming of GAG chains. The results are similar to other fluorescently labeled analogs and we propose that these compounds are too large and unpolar to efficiently function as GAG-primers. (c) 2007 Elsevier Ltd. All rights reserved.
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