Assay for type III collagenolytic activity in lung cancer tissue.

We developed a method for measuring the activity of type III collagenolytic enzyme in lung cancer tissue, using as substrate, type III collagen purified from human placenta. In this method [3H]propionate is used for labeling type III collagen, with bacterial collagenase used for making the standard curve. It, therefore, becomes possible to compare type III collagenolytic activity with those of other collagen subtypes (types I and IV). As this method is a fibril assay it is not susceptible to trypsin or other proteases. The average type III collagenolytic enzyme activity was higher in squamous cell carcinoma than in adenocarcinoma, while that of lung cancer tissue exceeded that of normal lung tissue. The activity of type III collagenase increased with the progression from one disease stage to the next.