| 1. |
- Mani, Katrin, et al.
(författare)
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HIV-Tat protein transduction domain specifically attenuates growth of polyamine deprived tumor cells.
- 2007
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Ingår i: Molecular Cancer Therapeutics. - 1538-8514. ; 6:2, s. 782-788
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Tidskriftsartikel (refereegranskat)abstract
- Polyamines are essential for tumor cell growth, and the polyamine pathway represents an attractive target for cancer treatment. Several polyamine transport proteins have been cloned and characterized in bacteria and yeast cells; however, the mechanism of polyamine entry into mammalian cells remains poorly defined, although a role for proteoglycans has been suggested. Here, we show that the HIV-Tat transduction peptide, which is known to enter cells via a proteoglycan-dependent pathway, efficiently inhibits polyamine uptake. Polyamine uptake–deficient mutant cells with intact proteoglycan biosynthesis (CHO MGBG) displayed unperturbed HIV-Tat uptake activity compared with wild-type cells, supporting the notion that HIV-Tat peptide interferes with polyamine uptake via competition for proteoglycan binding sites rather than a putative downstream transporter. HIV-Tat specifically inhibited growth of human carcinoma cells made dependent on extracellular polyamines by treatment with the polyamine biosynthesis inhibitor {alpha}-difluoromethylornithine; accordingly, the Tat peptide prevented intracellular accumulation of exogenous polyamines. Moreover, combined treatment with {alpha}-difluoromethylornithine and HIV-Tat efficiently blocked tumor growth in an experimental mouse model. We conclude that HIV-Tat transduction domain and polyamines enter cells through a common pathway, which can be used to target polyamine-dependent tumor growth in the treatment of cancer.
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| 2. |
- Abdelhady, Wael Awad, et al.
(författare)
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GPC1 (glypican 1)
- 2014
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Ingår i: Atlas of Genetics and Cytogenetics in Oncology and Haematology. - : INIST-CNRS. - 1768-3262. ; 18:7, s. 461-464
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Tidskriftsartikel (refereegranskat)abstract
- Review on GPC1, with data on DNA/RNA, on the protein encoded and where the gene is implicated.
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| 3. |
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| 4. |
- Abrahamsson, Carl-Olof, et al.
(författare)
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Xylosylated naphthoic acid-amino acid conjugates for investigation of glycosaminoglycan priming.
- 2008
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Ingår i: Carbohydrate Research. - : Elsevier BV. - 1873-426X .- 0008-6215. ; 343:9, s. 1473-1477
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Tidskriftsartikel (refereegranskat)abstract
- Three different series of xylosylated naphthoic acid-amino acid conjugates containing one or two amino acid residues were synthesized for the investigation of glycosaminoglycan priming and potential use as anti-tumor drugs. All xylosylated naphthoic acid-conjugates inhibited the growth of normal lung fibroblasts to some extent, whereas the growth of tumor derived T24 carcinoma cells was not affected. There was no correlation between amino acid conjugation, retention time and the antiproliferative activity. Only one compound initiated the priming of glycosaminoglycans. Modification of the naphthalene ring with one or two amino acid residues did not have any effect on proteoglycan biosynthesis or glycosaminoglycan priming in T24 carcinoma cells.
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| 5. |
- 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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| 6. |
- Aili, Ulrika, et al.
(författare)
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Attenuation of tumor growth by formation of antiproliferative glycosaminoglycans correlates with low acetylation of histone H3.
- 2010
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Ingår i: Cancer Research. - 1538-7445. ; 70:9, s. 3771-3779
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Tidskriftsartikel (refereegranskat)abstract
- Glycosaminoglycan (GAG) chains anchored to core proteins form proteoglycans, widely distributed cell-surface macromolecules with multiple functions, such as regulation of growth factor and cytokine signaling, cell-cell interactions, and uptake of biomolecules. The biosynthesis of GAG can be manipulated by xylosides attached to various hydrophobic groups, and we have earlier reported that a naphthoxyloside, 2-(6-hydroxynaphthyl) beta-D-xylopyranoside (XylNapOH), which serves as a primer for GAG synthesis, reduces tumor load up to 97% in vivo, despite lower efficiency in vitro. Here we show, using radiolabeled xylosides and coculture experiments, that XylNapOH-treated bladder and breast carcinoma cells secrete antiproliferative GAG chains that are taken up by both normal and cancer cells and transported to the cell nuclei where they induce an antiproliferative effect, accompanied by apoptosis. We also show that XylNapOH treatment lowers the level of histone H3 acetylation selectively in bladder and breast carcinoma cells without affecting expression of histone H3. However, XylNapOH-primed GAG chains from normal cells are not internalized and do not cause growth retardation. Using in vitro and in vivo C6 glioma cell and tumor models, we show that XylNapOH is much more effective in vivo than in vitro. We propose that, in vivo, the antiproliferative XylNapOH-primed GAG chains produced by tumor cells inhibit tumor growth in an autocrine fashion by formation of antiproliferative GAG chains on the xyloside prodrug, whereas no antiproliferative GAG chains are produced by surrounding normal cells. This is a novel mechanism for targeting tumor cells, making these xylosides promising drug candidates for antitumor therapy.
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| 7. |
- Awad, Wael, et al.
(författare)
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Improvements in the order, isotropy and electron density of glypican-1 crystals by controlled dehydration.
- 2013
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Ingår i: Acta Crystallographica. Section D: Biological Crystallography. - 1399-0047. ; 69:Pt 12, s. 2524-2533
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Tidskriftsartikel (refereegranskat)abstract
- The use of controlled dehydration for improvement of protein crystal diffraction quality is increasing in popularity, although there are still relatively few documented examples of success. A study has been carried out to establish whether controlled dehydration could be used to improve the anisotropy of crystals of the core protein of the human proteoglycan glypican-1. Crystals were subjected to controlled dehydration using the HC1 device. The optimal protocol for dehydration was developed by careful investigation of the following parameters: dehydration rate, final relative humidity and total incubation time Tinc. Of these, the most important was shown to be Tinc. After dehydration using the optimal protocol the crystals showed significantly reduced anisotropy and improved electron density, allowing the building of previously disordered parts of the structure.
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| 8. |
- Awad, Wael, et al.
(författare)
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Structural and Biophysical Characterization of Human EXTL3 : Domain Organization, Glycosylation, and Solution Structure
- 2018
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 57:7, s. 1166-1177
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Tidskriftsartikel (refereegranskat)abstract
- Heparan sulfate proteoglycans are proteins substituted with one or more heparan sulfate (HS) polysaccharides, found in abundance at cell surfaces. HS chains influence the activity of many biologically important molecules involved in cellular communication and signaling. The exostosin (EXT) proteins are glycosyltransferases in the Golgi apparatus that assemble HS chains on HSPGs. The EXTL3 enzyme mainly works as an initiator in HS biosynthesis. In this work, human lumenal N-glycosylated EXTL3 (EXTL3ΔN) was cloned, expressed in human embryonic kidney cells, and purified. Various biophysical and biochemical approaches were then employed to elucidate the N-glycosylation sites and the function of their attached N-glycans. Furthermore, the stability and conformation of the purified EXTL3ΔN protein in solution have been analyzed. Our data show that EXTL3ΔN has N-glycans at least at two positions, Asn290 and Asn592, which seem to be critical for proper protein folding and/or release. EXTL3ΔN is quite stable, as high temperature (∼59 °C) was required for denaturation. Deconvolution of the EXTL3ΔN far-UV CD spectrum revealed a substantial fraction of β sheets (25%) with a minor proportion of α-helices (14%) in the secondary structure. Solution small-angle X-ray scattering and dynamic light scattering revealed an extended structure suggestive of a dimeric arrangement and consisting of two distinct regions, narrow and broad, respectively. This is consistent with bioinformatics analyses suggesting a 3-domain structure with two glycosyltransferase domains and a coiled-coil domain.
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| 9. |
- Awad, W., et al.
(författare)
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Structural Aspects of N-Glycosylations and the C-terminal Region in Human Glypican-1
- 2015
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 290:38, s. 22991-23008
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Tidskriftsartikel (refereegranskat)abstract
- Glypicans are multifunctional cell surface proteoglycans involved in several important cellular signaling pathways. Glypican-1 (Gpc1) is the predominant heparan sulfate proteoglycan in the developing and adult human brain. The two N-linked glycans and the C-terminal domain that attach the core protein to the cell membrane are not resolved in the Gpc1 crystal structure. Therefore, we have studied Gpc1 using crystallography, small angle x-ray scattering, and chromatographic approaches to elucidate the composition, structure, and function of the N-glycans and the Cterminus and also the topology of Gpc1 with respect to the membrane. The Cterminus is shown to be highly flexible in solution, but it orients the core protein transverse to the membrane, directing a surface evolutionarily conserved in Gpc1 orthologs toward the membrane, where it may interact with signaling molecules and/or membrane receptors on the cell surface, or even the enzymes involved in heparan sulfate substitution in the Golgi apparatus. Furthermore, the N-glycans are shown to extend the protein stability and lifetime by protection against proteolysis and aggregation.
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| 10. |
- Belting, Mattias, et al.
(författare)
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Glypican-1 is a vehicle for polyamine uptake in mammalian cells. A pivotal role for nitrosothiol-derived nitric oxide.
- 2003
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 278:47, s. 47181-47189
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Tidskriftsartikel (refereegranskat)abstract
- Polyamines (putrescine, spermidine, and spermine) are essential for growth and survival of all cells. When polyamine biosynthesis is inhibited, there is up-regulation of import. The mammalian polyamine transport system is unknown. We have previously shown that the heparan sulfate (HS) side chains of recycling glypican-1 (Gpc-1) can sequester spermine, that intracellular polyamine depletion increases the number of NO-sensitive N-unsubstituted glucosamines in HS, and that NO-dependent cleavage of HS at these sites is required for spermine uptake. The NO is derived from S-nitroso groups in the Gpc-1 protein. Using RNA interference technology as well as biochemical and microscopic techniques applied to both normal and uptake-deficient cells, we demonstrate that inhibition of Gpc-1 expression abrogates spermine uptake and intracellular delivery. In unperturbed cells, spermine and recycling Gpc-1 carrying HS chains rich in N-unsubstituted glucosamines were co-localized. By exposing cells to ascorbate, we induced release of NO from the S-nitroso groups, resulting in HS degradation and unloading of the sequestered polyamines as well as nuclear targeting of the deglycanated Gpc-1 protein. Polyamine uptake-deficient cells appear to have a defect in the NO release mechanism. We have managed to restore spermine uptake partially in these cells by providing spermine NONOate and ascorbate. The former bound to the HS chains of recycling Gpc-1 and S-nitrosylated the core protein. Ascorbate released NO, which degraded HS and liberated the bound spermine. Recycling HS proteoglycans of the glypican-type may be plasma membrane carriers for cargo taken up by caveolar endocytosis.
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