Heparin is an excellent inhibitor of P-and L-selectin binding to the carbohydrate determinant, sialyl Lewis x . As a consequence of its anti-selectin activity, heparin attenuates metastasis and inflammation. Here we show that fucosylated chondroitin sulfate (FucCS), a polysaccharide isolated from sea cucumber composed of a chondroitin sulfate backbone substituted at the 3-position of the ␤-D-glucuronic acid residues with 2,4-disulfated ␣-L-fucopyranosyl branches, is a potent inhibitor of P-and L-selectin binding to immobilized sialyl Lewis x and LS180 carcinoma cell attachment to immobilized P-and L-selectins. Inhibition occurs in a concentration-dependent manner. Furthermore, FucCS was 4 -8-fold more potent than heparin in the inhibition of the P-and L-selectin-sialyl Lewis The surface of carcinoma cells exhibits altered glycosylation patterns (1-5), often containing highly branched or sialylated oligosaccharides, especially fucosylated glycans such as sialylLewis X (Sia␣2-3Gal␤1-4(Fuc␣1-3)GlcNAc) and sialyl-Lewis a (Sia␣2-3Gal␤1-3(Fuc␣1-4)GlcNAc). The presence of these oligosaccharides in tumor cells directly correlates with a poor prognosis for cancer patients because of tumor progression and metastatic spread (1-5). The sLe X -oligosaccharides 4 from carcinoma cells act as ligands of the three members of the selectin family of cell adhesion molecules. E-, P-, and L-selectins are vascular receptors for certain normal glycoproteins that contain sialyl-Lewis x,a found on leukocytes and endothelium (6 -8). The selectins also participate in hematogenous metastasis by mediating the interactions of tumor cells with platelets and endothelium (1-3). Hematogenous metastasis occurs through a series of sequential events involving the intravasation of tumor cells into the bloodstream, evasion of innate immune surveillance, adhesion to vascular endothelium of distant organs with subsequent extravasation, and colonization of tissues. It has been proposed that these microemboli of tumor cells with platelets and leukocytes allow tumor cells to evade the immune defenses and eventually colonize distant organs, forming metastatic foci (9 -15). Several studies have shown that a few minutes after intravenous injection, tumor cells are detected in emboli inside pulmonary capillaries in association with platelets and fibrin.Studies from several groups have indicated that tumor metastasis in experimental animals is inhibited by heparin (16 -19). Some clinical studies have also shown a beneficial effect of heparin in some types of human cancer (20 -24). The antimetastatic effect of heparin does not reflect its anticoagulant activity (25, 26) but rather relates to the ability of heparin to inhibit the interaction of sialyl Lewis x,a -rich oligosaccharides on tumor cells with P-selectin on platelets (16,27). In the presence of heparin, tumor cells lose the protection conferred by platelets becoming susceptible to the potentially cytotoxic action of immune effector cells, which leads to the inhibition of metastasis. A single intravascul...

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We developed a simple methodology for labeling sulfated glycosaminoglycans (GAGs) in adult Drosophila melanogaster and studied some aspects of the biosynthesis and metabolism of these polymers during development. Adult D. melanogaster flies were fed with Na(2)(35)SO(4) for 72 h. During this period, (35)S-sulfate was incorporated into males and females and used to synthesize (35)S-sulfate-heparan sulfate (HS) and (35)S-sulfate-chondroitin sulfate (CS). The incorporation of (35)S-sulfate into HS was higher when compared to CS. In a pulse-chase experiment, we observed that (35)S-sulfate incorporated into adult female was recovered in embryos and used for the synthesis of new (35)S-sulfate-GAGs after 2 h of embryonic development. The synthesis of CS was higher than that of HS, indicating a change in the metabolism of these glycans from adult to embryonic and larval stages. Analysis of the CS in embryonic and larval tissues revealed the occurrence of nonsulfated and 4-sulfated disaccharide units in embryos, L1 and L2. In L3, in addition to these disaccharides, we also detected significant amount of 6-sulfated units that are reported here for the first time. Immunohistochemical analysis indicated that HS and CS were present in nonequivalent structures in adult and larval stages of the fly. Overall, these results indicate that (35)S-sulfate-precursors are transferred from adult to embryonic and larval tissues and used to assemble different morphological structures during development.

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