The synthesis of the trisaccharide β-D-Galp-(1 → 3)-β-D-GalpNAc-(1 → 3)-α-D-Galp-1-OPr (2) and of the tetrasaccharide α-L-Fucp-(1 → 2)-β-D-Galp-(1 → 3)-β-D-GalpNAc-(1 → 3)-α-D-Galp-1-OPr (3), starting from the disaccharidic dihydrooxazole donor 5, is described. Glycosylation of 5 with 6 in the presence of Me3SiOTf gave the trisaccharide 7 which was deprotected with standard methods to give, via 8, compound 2. Alternatively, protection of 8 as the 4',6'-O-benzylidene derivative 9 followed by glycosylation with 10 and by standard deprotection afforded the tetrasaccharide 3. Biological testing showed that trisaccharide 2 is unable to inhibit the binding of the monoclonal antibody MBr1 to the target tumor cells MCF7, while tetrasaccharide 3 inhibits the binding in ca. 7-fold extent with respect to the previously tested trisaccharide α-L-Fucp-(1 → 2)-β-D-Galp-(1 → 3)-β-D-GalpNAc-1-OPr. These results indicate that the galactose corresponding to the unit D of compound 1 plays an important role in defining the MBr1-recognized epitope and confirm the essential role of fucose for MAb recognition.
Oligosaccharides related to tumor-associate antigens. Part 3. Synthesis of the propyl glycosides of the trisaccharide β-D-Galp-(1→3)-β-D-GalpNAc-(1→3)-α-D-Galp and of the Tetrasaccharide α-L-Fucp-(1→2)-β-D-Galp-(1→3)-β-D-GalpNAc-(1→3)-α-D-Galp, components of a tumor antigen recognized by the antibody MBr1 / L. Lay, L. Panza, G. Russo, D. Colombo, F. Ronchetti, E. Adobati, S. Canevari. - In: HELVETICA CHIMICA ACTA. - ISSN 0018-019X. - 78:3(1995), pp. 533-538. [10.1002/hlca.19950780302]
Oligosaccharides related to tumor-associate antigens. Part 3. Synthesis of the propyl glycosides of the trisaccharide β-D-Galp-(1→3)-β-D-GalpNAc-(1→3)-α-D-Galp and of the Tetrasaccharide α-L-Fucp-(1→2)-β-D-Galp-(1→3)-β-D-GalpNAc-(1→3)-α-D-Galp, components of a tumor antigen recognized by the antibody MBr1
L. LayPrimo
;G. Russo;D. Colombo;F. Ronchetti;
1995
Abstract
The synthesis of the trisaccharide β-D-Galp-(1 → 3)-β-D-GalpNAc-(1 → 3)-α-D-Galp-1-OPr (2) and of the tetrasaccharide α-L-Fucp-(1 → 2)-β-D-Galp-(1 → 3)-β-D-GalpNAc-(1 → 3)-α-D-Galp-1-OPr (3), starting from the disaccharidic dihydrooxazole donor 5, is described. Glycosylation of 5 with 6 in the presence of Me3SiOTf gave the trisaccharide 7 which was deprotected with standard methods to give, via 8, compound 2. Alternatively, protection of 8 as the 4',6'-O-benzylidene derivative 9 followed by glycosylation with 10 and by standard deprotection afforded the tetrasaccharide 3. Biological testing showed that trisaccharide 2 is unable to inhibit the binding of the monoclonal antibody MBr1 to the target tumor cells MCF7, while tetrasaccharide 3 inhibits the binding in ca. 7-fold extent with respect to the previously tested trisaccharide α-L-Fucp-(1 → 2)-β-D-Galp-(1 → 3)-β-D-GalpNAc-1-OPr. These results indicate that the galactose corresponding to the unit D of compound 1 plays an important role in defining the MBr1-recognized epitope and confirm the essential role of fucose for MAb recognition.Pubblicazioni consigliate
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