CELL-SURFACE SULFOGLYCOLIPIDS ARE INVOLVED IN THE ATTACHMENT OF RENAL-CANCER CELLS TO LAMININ

We investigated the role of sulfoglycolipids on human renal-cell carci noma cells (SMKT-R3) in the attachment to a substrate adhesive protein , laminin. SMKT-R3 cells over-express sulfoglycolipids, including SM2, SM3 and SM4. When acidic glycolipid fractions were extracted from SMK T-R3 cells, separated by HPTLC, and then overlaid with laminin, lamini n bound specifically to SM3 and SM4. A monoclonal antibody, Sulph-1, r eacting with SM3 and SM4 inhibited attachment of the cells to laminin but not to fibronectin, in a dose-dependent manner. In addition, when exogenous SM4 was incorporated into the cells, their attachment to lam inin, but not to fibronectin, was enhanced. On the other hand, the inc orporation of GalCer, which is a precursor of SM4, had no effect on ad herence of the cells to laminin or to fibronectin. We also assayed hap totaxis, tumor-cell migration along a gradient of substratum-bound lam inin. The incorporation of SM4 into the cells caused an approximately 3-fold increase of the haptotactic response to laminin compared with n on- or GalCer-incorporation. These results taken together suggest that sulfoglycolipids on renal-cancer cells are involved in attachment to laminin and that they can modulate the metastatic potential of renal-c ell carcinoma cells. (C) 1994 Wiley-Liss, Inc.