Role of CD44H carbohydrate structure in neuroblastoma adhesive properties

Background. CD44 represents a heterogeneous group of surface glycoproteins involved in cell-cell and cell-matrix interactions. CD44H is the major rece ptor for hyaluronate, and most if not all CD44H known functions are attribu ted to its ability to recognize hyaluronate. We have previously demonstrate d a lack of CD44 expression in high stages and NMYC-amplified tumors and fu rther have shown that NMYC-amplified cell lines either did not express CD44 at all or expressed a nonfunctional receptor. On the other hand, nonamplif ied cells constitutively expressed an active receptor, suggesting that abse nce of CD44-mediated hyaluronate binding could be related to increased mali gnancy in human neuroblastoma. Procedure. In the present study we have comp ared the glycosylated structure of CD44 expressed by NMYC amplified vs. non amplified cell lines in relation to their adhesive properties for hyalurona te. These adhesive properties were measured after modifications of the carb ohydrate structure with enzymes and inhibitors of N- or O-linked glycosylat ion. Results and Conclusions. Our results indicate that increased sialylati on, defective N-linked glycosylation, and substitution of the CD44 glycopro tein with keratan sulfate glycosaminoglycan might include modifications obs erved on neuroblastoma cells that could account for the inability of the re ceptor to bind hyaluronate. Med. Pediatr. Oncol. 36:139-141, 2001. (C) 2001 Wiley-Liss, Inc.