Cell type-specific roles of carbohydrates in tumor metastasis

Protein- or lipid-bound glycans have been shown to play important roles in many biological processes; their functional diversity is due primarily to the multiple linkages, branching patterns, and terminal modifications seen in these glycans. Furthermore, one particular glycan may play different roles depending on the biological system. Sialyl Lewis X oligosaccharides, prototypic ligands for E-, L-, and P-selectins, are essential for naive lymphocyte homing to secondary lymphoid organs. They have also been implicated clinically in tumor metastasis and poor prognosis of cancer patients. In this chapter, we describe the protocol for the formation of lung tumor after intravenous injection of B16 melanoma cells. In our study, B16 melanoma cells formed more tumors when the cells were transfected with fucosyltransferase-III to express sialyl Lewis X. In the second experimental protocol, we describe metastatic tumor formation at the draining lymph node after primary tumor was formed at the footpad. In this experimental system, natural killer (NK) cell recruitment to the draining lymph node was found to be critical to suppress tumor metastasis and this tumor suppression is dependent on L-selectin-mediated trafficking of NK cells to the lymph nodes.