Interaction of CD44 with different forms of hyaluronic acid. Its role in adhesion and migration of tumor cells.

Interaction between hyaluronic acid (HA) and CD44 has been considered a key event in tumor invasion and metastasis. HA is a linear, high molecular weight glycosaminoglycan in its native state, but fragmented low molecular forms are found at sites ofneoplastic or inflammatory infiltrates. Both high and low molecular weights HA are involved in diverse biological functions. In this study, we used two clonal variants of a T cell murine lymphoma designated LBLa and LBLc. These cell lines were found to differ in their in vivo and in vitro growth rates. LBLa grew faster and exhibited an enhanced invasive capacity as compared to LBLc. In contrast, cell lines did not differ in the expression of surface markers (CD8, CD24, CD25, CD44, and CD18), or in their capacity to bind HA. However, LBLa cells exhibited higher capacity to migrate to low molecular weight HA than did LBLc. Migration was mediated by CD44 since it was abrogated by anti-CD44 monoclonal antibody as well as by hyaluronidase. We suggest that interaction between CD44 and low molecular weight HA may trigger migration mechanisms in LBLa cells, thus contributing to enhanced invasive cell capacity.