VITAMIN-E SUCCINATE INDUCTION OF HL-60 CELL-ADHESION - A ROLE FOR FIBRONECTIN AND A 72-KDA FIBRONECTIN-BINDING MOLECULE

HL-60 cells, growing as single cells in suspension, exhibit marked cel l-cell adhesion when treated for 24 hours with 10 mu g/ml RRR-alpha-to copheryl succinate, also called vitamin E succinate (VES). VES-induced cell-cell adhesion is dependent on divalent cations and a functional cytoskeleton and is protein mediated. Cell adhesion molecules CD11a/CD 18, CD11b/CD18, CD29, and CD54 do not appear to be mediating VES-induc ed cell adhesion. HL-60 cells treated with VES adhere to fibronectin-c oated plastic and secrete elevated levels of fibronectin. A 72-kDa fib ronectin-binding membrane molecule was detected on VES-treated HL-60 c ells, and antibodies to fibronectin were shown to inhibit VES-induced cell aggregation. VES induction of HL-60 cell-cell adhesion is propose d to result from increased amounts of extracellular fibronectin bindin g to VES-induced cell surface fibronectin-binding molecules.