Core 2 beta 1,6-N-acetylglucosaminyltransferases and alpha 1,3-fucosyltransferases regulate the synthesis of O-glycans on selectin ligands on oral cavity carcinoma cells

Selectin-dependent cell binding has importance in the extravasation of bloo d-circulating tumor cells and in the generation of metastases. Cell surface glycoproteins; decorated with sialylated, fucosylated epitopes, such as si alyl Lewis(x) (sLe(x)) are ligands for selectins. Not only terminal sLex mo ieties but also proximal core structures contribute to the formation of bin ding epitopes for selectins. Core 2 beta1,6-N-acetylglucosaminyltransferase s (C2GnT) and alpha1,3-fucosyltransferases (alpha1,3-FucT) have been sugges ted to be the rate-limiting enzymes in the synthesis of selectin ligands. W e analyzed oral cavity epithelial carcinoma cell lines and showed their exp ression of RNA transcripts for C2GnT and alpha1,3-FucT, identified alpha1,3 -FucT enzyme activities, and analyzed the cell surface sLe(x) expression le vels. Neither the pattern of expressed enzymes nor the alpha1,3-FucT activi ty directly predicted the binding capacity of E-selectin. However, only the sLe(x)-expressing cell lines were capable of binding to E-selectin, but no t to P-selectin, thus putatively promoting the selectin-mediated metastasis . These findings suggest that C2GnT in combination with alpha1,3-Fuc-T cont ribute to the selectin-mediated metastasis in oral cavity carcinomas.