| 1. |
- Bergefall, Kicki, 1975, et al.
(författare)
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Chondroitin sulfate characterized by the E-disaccharide unit is a potent inhibitor of herpes simplex virus infectivity and provides the virus binding sites on gro2C cells.
- 2005
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Ingår i: The Journal of biological chemistry. - 0021-9258. ; 280:37, s. 32193-9
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Tidskriftsartikel (refereegranskat)abstract
- Although cell surface chondroitin sulfate (CS) is regarded as an auxiliary receptor for binding of herpes simplex virus to cells, and purified CS chain types A, B, and C are known to interfere poorly or not at all with the virus infection of cells, we have found that CS type E (CS-E), derived from squid cartilage, exhibited potent antiviral activity. The IC(50) values ranged from 0.06 to 0.2 mug/ml and substantially exceeded the antiviral potency of heparin, the known inhibitor of virus binding to cells. Furthermore, in mutant gro2C cells that express CS but not heparan sulfate, CS-E showed unusually high anti-herpes virus activity with IC(50) values of <1 ng/ml. Enzymatic degradation of CS-E with chondroitinase ABC abolished its antiviral activity. CS-E inhibited the binding to cells of the purified virus attachment protein gC. A direct interaction of gC with immobilized CS-E and inhibition of this binding by CS-E oligosaccharide fragments greater than octasaccharide were demonstrated. Likewise, the gro2C-specific CS chains interfered with the binding of viral gC to these cells and were found to contain a considerable proportion (13%) of the E-disaccharide unit, suggesting that this unit is an essential component of the CS receptor for herpes simplex virus on gro2C cells and that the antiviral activity of CS-E was due to interference with the binding of viral gC to a CS-E-like receptor on the cell surface. Knowledge of the determinants of antiviral properties of CS-E will help in the development of inhibitors of herpes simplex virus infections in humans.
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| 2. |
- Bergefall, Kicki, 1975
(författare)
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Interaction of herpes simplex virus with cell surface glycosaminoglycans as a target for antiviral intervention
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Herpes simplex virus (HSV) infections in humans are predominantly manifested as oral cold sores or genital ulcers. As HSV infects cells by interaction with cell surface heparan sulfate (HS) and/or chondroitin sulfate (CS), the aim of the research work presented in this thesis was to explore the possibility of antiviral intervention with compounds that mimic HS or CS. Three structurally distinct compounds were found to target this step of HSV-cell interaction thus preventing the HSV infection of cells. These include (i) the low molecular weight HS-mimetic PI-88, (ii) CS type E (CS-E) derived from squid cartilage, and (iii) the monosulfated cyclitol SC1. PI-88 is a mixture of highly sulfated mannose-containing di- to hexa-saccharides that was previously explored as an anti-cancer drug. In this thesis PI-88 was found to be a potent inhibitor of the cell-to-cell spread of HSV. This feature of the virus is essential for the development of both viral plaques in cell cultures and of oral or genital lesions in humans. One structural feature of PI-88, its low molecular weight, was found to be important for the antiviral properties as PI-88 but not the high molecular weight HS-mimetic heparin could inhibit the cell-to-cell spread of HSV. The antiviral activity of PI-88 is very likely due to its ability to access the narrow intercellular space where PI-88 was demonstrated to block the interaction of viral envelope glycoproteins gB, gC, and gD with cellular HS.Although cell surface CS is regarded as an auxiliary receptor for HSV and purified preparations of CS types A, B, and C are known to be poor inhibitors of HSV invasion of cells, in this thesis it was found that CS type E, from squid cartilage, was one of the most potent inhibitors of initial virus adherence to cultured cells. The concentrations of CS-E that inhibited the virus infectivity by 50% (IC50) were approximately 0.1 µg/ml in normal cells, and <1 ng/ml in mutant CS-expressing cells. In addition, because disaccharide analysis of CS forms found on the cell surface revealed the presence of E disaccharide units, CS-E may block HSV invasion of cells by interference with the virus binding to the E unit of the cell surface CS.By screening for the anti-HSV activity of a mini-library of 96 compounds, previously synthesized to search for inhibitors of protein-HS interaction, a monosulfated cyclitol molecule designated SC1 was discovered to completely inhibit HSV infectivity in cultured cells. SC1 was found to target and to inactivate the viral particle. Complete inactivation of HSV type 1 and type 2 particles occurred within 5 min at 37°C and 15 30 min at 37°C respectively. In addition SC1, in contrast to some other virus-inactivating agents, exhibited substantial selectivity in its antiviral action as the concentration of SC1 that was toxic for cells was at least fifty fold higher than the virus-inactivating doses. The anti-HSV activity of SC1 was found to be due to the inactivation of viral components other than those required for the virus attachment to cells.In conclusion three novel antivirals, discovered and described in this thesis, are proposed as candidate compounds for prevention and/or treatment of HSV infections in humans.
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| 3. |
- Ekblad, Maria, 1978, et al.
(författare)
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Molecular basis for resistance of herpes simplex virus type 1 mutants to the sulfated oligosaccharide inhibitor PI-88.
- 2007
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Ingår i: Virology. - : Elsevier BV. - 0042-6822. ; 367:2, s. 244-52
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Tidskriftsartikel (refereegranskat)abstract
- Herpes simplex virus type 1 variants selected by virus propagation in cultured cells in the presence of the sulfated oligosaccharide PI-88 were analyzed. Many of these variants were substantially resistant to the presence of PI-88 during their initial infection of cells and/or their cell-to-cell spread. Nucleotide sequence analysis revealed that the deletion of amino acids 33-116 of gC but not lack of gC expression provided the virus with selective advantage to infect cells in the presence of PI-88. Purified gC (Delta33-116) was more resistant to PI-88 than unaltered protein in its binding to cells. Alterations that partly contributed to the virus resistance to PI-88 in its cell-to-cell spread activity were amino acid substitutions Q27R in gD and R770W in gB. These results suggest that PI-88 targets several distinct viral glycoproteins during the course of initial virus infection and cell-to-cell spread.
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| 4. |
- Karoli, Tomislav, et al.
(författare)
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Synthesis, biological activity, and preliminary pharmacokinetic evaluation of analogues of a phosphosulfomannan angiogenesis inhibitor (PI-88).
- 2005
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Ingår i: Journal of medicinal chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 48:26, s. 8229-36
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Tidskriftsartikel (refereegranskat)abstract
- The phosphosulfomannan 1 (PI-88) is a mixture of highly sulfated oligosaccharides that is currently undergoing clinical evaluation in cancer patients. As well as its anticancer properties, 1 displays a number of other interesting biological activities. A series of analogues of 1 were synthesized with a single carbon (pentasaccharide) backbone to facilitate structural characterization and interpretation of biological results. In a fashion similar to 1, all compounds were able to inhibit heparanase and to bind tightly to the proangiogenic growth factors FGF-1, FGF-2, and VEGF. The compounds also inhibited the infection of cells and cell-to-cell spread of herpes simplex virus (HSV-1). Preliminary pharmacokinetic data indicated that the compounds displayed different pharmacokinetic behavior compared with 1. Of particular note was the n-octyl derivative, which was cleared 3 times less rapidly than 1 and may provide increased systemic exposure.
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