TRIFLAVIN, AN ARG-GLY-ASP-CONTAINING PEPTIDE, INHIBITS HUMAN CERVICAL-CARCINOMA (HELA) CELL-SUBSTRATUM ADHESION THROUGH AN RGD-DEPENDENT MECHANISM

Triflavin, a 7.5-kDa cysteine-rich polypeptide purified from Trimeresu rus flavoviridis snake venom, belongs to a family of RGD-containing pe ptides, termed disintegrins, that have been isolated from the venoms o f various vipers and shown to be potent inhibitors of platelet aggrega tion. The interaction of tumor cells with extracellular matrices such as fibronectin, vitronectin, and collagen has been shown to be mediate d through a family of cell surface receptors that specifically recogni ze an arginine-glycine-aspartic acid (RGD) sequence within each adhesi ve protein. In this study, we show that triflavin dose-dependently inh ibited adhesion of human cervical carcinoma (HeLa) cells to extracellu lar matrices (ECMs; i.e., fibronectin, fibrinogen, and vitronectin). O n the other hand, triflavin exerted a limited inhibitory effect on cel l adhesion to laminin and collagen (type I and IV). On a molar basis, triflavin is approximately 800 times more potent than Gly-Arg-Gly-Asp- Ser (GRGDS) at inhibiting cell adhesion. When immobilized on plate, tr iflavin significantly promoted HeLa cell adhesion, and this attachment was inhibited by GRGDS. Furthermore, FITC-conjugated triflavin bound to cells in a saturable manner and its binding was inhibited by GRGDS. In addition, triflavin did not affect [H-3]thymidine uptake of HeLa c ells during a 3-day incubation. These results suggest that triflavin p robably binds to integrin receptors expressed on HeLa cell surface via its RGD sequence within its molecule, thereby inhibiting the adhesion of extracellular matrices to HeLa cells.