(A) Western blot identification of MMP-2 in CEM-conditioned medium. Gelatin affinity-purified–conditioned medium from 10⁸ CEM cells cultured for 24 hours on plastic (P) or in the presence of soluble fibronectin at 10 μg/mL (Fn) was subjected to Western blot analysis with the MoAb Ab-3 against MMP-2. (B) RT-PCR demonstration of MMP-2 transcripts in CEM cells. PCR-amplified cDNA obtained from resting CEM cells (lane 1) and CEM cells exposed to fibronectin at 10 μg/mL for 4 hours (lane 2). Simultaneous amplification of the housekeeping gene β2-microglobulin is shown to ensure an equivalent amount of template in both conditions. Lane 3 shows the nested PCR product obtained from the 694 bp fragment using previously published internal primers.22 Lane 4 shows the Sac I restriction fragments of the 694 bp fragment.