%0 Journal Article
%T Thiolactosides: Scaffolds for the Synthesis of Glycolipids in Animal Cells
%A Masako Mori
%A Maria Carmelita Z. Kasuya
%A Mamoru Mizuno
%A Kenichi Hatanaka
%J International Journal of Carbohydrate Chemistry
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/267208
%X Various glycolipids were synthesized using thiolactosides as scaffolds for glycosylation in animal cells. The basic building blocks, n-dodecyl ¦Â-D-thiolactoside (¦Â-LacSC12) and n-dodecyl ¦Á-D-thiolactoside (¦Á-LacSC12), were chemically synthesized in 2 steps: glycosylation followed by deacylation. The thiolactosides were administered to animal cells in culture and served as substrates for cellular enzyme-catalyzed glycosylation. Incubation of mouse melanoma B16 cells in the presence of ¦Â-LacSC12 or ¦Á-LacSC12 resulted in sialylation of the terminal galactose residue and gave a GM3-type ganglioside. Administration of ¦Â-Lac SC12 in Madin-Darby canine kidney (MDCK) cells likewise gave a GM3-type ganglioside. On the other hand, introduction of ¦Â-LacSC12 in African green monkey kidney (Vero) cells gave Gb3- and Gb4-type glycolipids aside from GM3-type ganglioside. In the course of the study, significant changes in B16 cell morphology and elevated secretion of melanin were also observed. 1. Introduction Sulfur-containing compounds are gaining wide attention due to their potential application in the pharmaceutical industry as carbohydrate-based therapeutics or diagnostic agents. Thioglycosides, in which the glycosidic oxygen has been replaced by sulfur, are valuable stable glycoside analogues. The S-analogues of natural glucosides are resistant to enzymatic hydrolysis and have been proven to be useful glycosidase inhibitors with potential as therapeutics [1]. For example, thioglycosides showed promising application in the control of hyperglycemia in patients with diabetes by inhibiting the sodium-D-glucose transporter (SGLT) expressed in Chinese hamster ovary (CHO) cells [2]. Suzuki and his coworkers reported that S-glycoside analogues of gangliosides possess inhibitory activity for the influenza virus sialidase [3]. Novel linear polymers bearing thiosialosides as pendant-type epitopes have also been reported as influenza neuraminidase inhibitors [4]. The priming of glycosphingolipid synthesis by lactosyl ceramide analogues having nondegradable thioglucosidic linkages inhibited the cell surface expression of endogenous GM3 in B16 cells [5]. The S-glycosides of gangliosides have also been reported as inhibitors of endoglycoceramidase, the enzyme that hydrolyzes the glycosidic linkage between the oligosaccharide and ceramide [6, 7]. Thioglycosides are used as glycosyl donors in the synthesis of biologically important oligosaccharides. They are among the widely used glycosyl donors considering the ease of preparation and shelf stability. Thioglycosides are
%U http://www.hindawi.com/journals/ijcc/2011/267208/