Is there a role for fibronectin upon true histiocytic lymphoma progression?

Cell interaction with extracellular matrix is a crucial event for various biological processes, including tumor progression. Although not exclusively, these interactions are frequently mediated by bidirectional signaling receptors known as integrins. Using a human histiocytic lymphoma-derived cell line (U-937), we evaluated the effects of ECM proteins and their integrin-type receptors in the regulation of cell attachment, proliferation, migration and survival. Fibronectin induces higher cell attachment in vitro when compared to laminin. Fibronectin also promotes a decrease in cell migration but do not modulate cell proliferation and death. Pre-incubation of U-937 cells with VLA-5 antagonistic peptides inhibited attachment of the cells to fibronectin-coated substrates. In a second vein, we observed that lymph node specimens obtained from diagnosed patient for true histiocytic lymphoma had greater deposition of fibronectin (but not laminin) around malignant clones. These results suggest that fibronectins play a relevant role in the establishment and progression of true histiocytic lymphoma cells.