| 1. |
- Kurup, Sindhulakshmi, et al.
(författare)
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Characterization of anti-heparan sulfate phage display antibodies AO4B08 and HS4E4
- 2007
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 282:29, s. 21032-21042
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Tidskriftsartikel (refereegranskat)abstract
- Heparan sulfates (HS) are linear carbohydrate chains, covalently attached to proteins, that occur on essentially all cell surfaces and in extracellular matrices. HS chains show extensive structural heterogeneity and are functionally important during embryogenesis and in homeostasis due to their interactions with various proteins. Phage display antibodies have been developed to probe HS structures, assess the availability of protein-binding sites, and monitor structural changes during development and disease. Here we have characterized two such antibodies, AO4B08 and HS4E4, previously noted for partly differential tissue staining. AO4B08 recognized both HS and heparin, and was found to interact with an ubiquitouys, N-, 2-O-, and 6-O-sulfated saccharide motif, including an internal 2-O-sulfate group. HS4E4 turned out to preferentially recognize low-sulfated HS motifs containing iduronic acid, and N-sulfated as well as N-acetylated glucosamine residues. Contrary to AO4B08, HS4E4 did not bind highly O-sulfated structures such as found in heparin.
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| 2. |
- Welch, Johanna E, et al.
(författare)
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Single chain fragment anti-heparan sulfate antibody targets the polyamine transport system and attenuates polyamine-dependent cell proliferation.
- 2008
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Ingår i: International Journal of Oncology. - 1019-6439. ; 32:4, s. 749-756
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Tidskriftsartikel (refereegranskat)abstract
- The growth-promoting polyamines are polybasic compounds that efficiently enter cancer cells by as yet incompletely defined mechanisms. Strategies to inhibit their internalization may have important implications in the management of tumor disease. Here, we show that cellular binding and uptake of polyamines are inhibited by a single chain variable fragment anti-heparan sulfate (HS) antibody. Polyamine uptake was inhibited in a dose-dependent manner, and was associated with compensatory up-regulation of ornithine decarboxylase (ODC), i.e. the key enzyme of the polyamine biosynthesis pathway. Conversely, depletion of intracellular polyamines by the specific ODC-inhibitor alpha-difluoromethylornithine (DFMO) resulted in increased cellular binding of polyamine and anti-HS antibody. Importantly, anti-HS antibody also efficiently targeted DFMO-induced polyamine uptake, and combined polyamine biosynthesis inhibition by DFMO, and uptake inhibition by anti-HS antibody attenuated tumor cell proliferation in vitro. In conclusion, cell-surface HS proteoglycan is a relevant target for antibody-mediated inhibition of the uptake of polyamines, and polyamine-dependent cell proliferation.
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