Highly activated matrix metalloproteinase-2 secreted from clones of metastatic lung nodules of nude mice injected with human fibrosarcoma HT1080

The promoting effects of matrix metalloproteinase-2 (MMP-2) on lung metasta sis of human fibrosarcoma cells (HT1080) were studied using nude mice, The fourth generation of HT1080 was established by consecutive clonal selection of metastatic lung nodules formed by intravenous transplantation. MMP-2 an d MMP-9 in the culture supernatants of the first and fourth generation cell s were analyzed by gelatin zymography and Western blotting, and quantified by scanning densitometry. In gelatin zymograms, mean ratios of values for t he 59-kDa band (the active form of MMP-2) to those for the 72-kDa band (the inactive form of hlMP-2) for optical density; area, and volume measured by densitometry were 1.44 +/- 0.12, 0.93 +/- 0.05, and 1.27 +/- 0.20, respect ively, in the culture supernatant of fourth generation cells isolated from metastatic lung nodules. These values were significantly (P < 0.01) higher than those of first generation cells (0.70 +/- 0.04, 0.48 +/- 0.01, and 0.5 7 +/- 0.42). Three weeks after intravenous transplantation of HT1080 cells into nude mice, the incidence of lung metastasis and mean number and diamet er of metastatic nodules formed by injection of first generation cells were 20% (2 of 10 mice), 2.9 +/- 0.2 and 2.0 +/- 0.2 mm, respectively; while th ey were 100%, 99.8 +/- 7.2 and 4.3 +/- 0.3 mm following injection of fourth generation cells. These findings suggest that the active MMP-2 produced by human fibrosarcoma cells is important for the cells to form lung metastati c lesions in nude mice. (C) 1999 Elsevier Science Ireland Ltd. All rights r eserved.