Collagen metabolism disturbances are accompanied by an increase in prolidase activity in lung carcinoma planoepitheliale

One of the consequences of neoplastic transformation is deregulation of tis sue collagen metabolism. Although metalloproteinases initiate the breakdown of collagen in lung carcinoma, the final step of collagen degradation is m ediated by prolidase (E.C.3.4.13.9). We investigated whether prolidase acti vity could reflect disturbances of collagen metabolism in human lung carcin oma planoepitheliale (Ca pl.). Ten human lung Ca pl. and 10 samples of norm al lung parenchyma were compared with respect to prolidase activity and exp ression (western immunoblot), the content of collagen and collagen degradat ion products (free and bound hydroxyproline determination), pl integrin sub unit expression (western immunoblot) and collagenolytic activity (zymograph y). An increase in collagen content (66%, P < 0.05), free proline pool (50% , P < 0.05) and collagenolytic activity was accompanied by a significant in crease in the prolidase activity (106%, P < 0.05) and its expression in Ca pl. No differences were found between Ca pl. and the control lung tissue wi th respect to <beta>(1) integrin expression. Prolidase activity may reflect disturbances in tissue collagen metabolism in lung Ca pl. and it may, ther efore, serve as a sensitive marker of the disease.