(A) Inhibition of fibronectin-induced MMP-2 and MMP-9 by blocking MoAb against integrin  chains. 10⁷ CEM cells per condition were preincubated with medium alone or with MoAb against ₄, _5, and _V integrin chains (fibronectin receptors); ₆ integrin chain (a laminin receptor); or the anti-CD20 93.1B3 (a B-cell lineage marker) before exposure to fibronectin. Conditioned medium was concentrated and subjected to gelatin zymography. Graph shows variation in gelatinolytic signals compared with the signal obtained with untreated cells exposed to fibronectin. (B) Membrane-associated MMP-2 expression induced by fibronectin-derived synthetic peptides. CEM cells were exposed to GRGDSPC, EILDVSPT, a combination of both, or to the control peptide GRGES at 100 μg/mL for 16 hours. Histograms show distribution of fluorescence intensity in 5 × 10³ cells per condition incubated with the MoAb Ab-3 recognizing MMP-2. (C) Pro-MMP-2 and pro-MMP-9 production stimulated by fibronectin-derived synthetic peptides. 2 × 10⁷ CEM cells were cultured on plastic (lane 1) or on plastic coated with GRGDSPC (lane 2), EILDVSPT(lane 3), or both (lane 4) at 100 μg/mL. The conditioned medium obtained after 48 hours was concentrated and subjected to gelatin zymography.