The role of plasminogen in cell-mediated collagen degradation.

The ability of VX2 tumour cells and chondrocytes to degrade radiolabelled collagen films was shown to be dependent on the presence of the serum proteinase plasminogen. Degradation of collagen films in the presence of plasminogen was inhibited by addition of exogenous TIMP indicating that such lysis was mediated by collagenase. VX2 cells required ten times less plasminogen than chondrocytes to effect comparable degradation; this result was probably related to the observation that VX2 cells did not synthesize the specific tissue inhibitor of metalloproteinases, TIMP.