Changes in the collagenolytic activity released by primary VX-2 carcinoma cultures as a function of tumor growth.

Serum-free media of minced tissue cultures of VX-2 rabbit carcinoma contained a specific collagenolytic activity capable of releasing soluble radioactive peptides from [14C]-labeled collagen fibrils. It was also capable of reducing the viscosity of acid-soluble collagen solutions by cleaving the tropocollagen (TC) molecules primarily at one site to TCA (75%) and TCB (25%) fragments. Three chromatographic fractions were separated by gel filtration: F1, (MW 85-110,000) present in larger amounts in early cultures of younger tumor tissue; F2, (MW-35-40,000) the major component with maximum production in the day 3 media of younger and advanced tumor tissues; F3, (MW 18-22,000) the minor component. Early cultures of younger tumor tissue contained a latent collagenase and were subject to trypsin activation suggesting the presence of inactive enzyme precursors or an enzyme-inhibitor complex.