ELEVATED LEVELS OF M-R-92,000 TYPE-IV COLLAGENASE DURING TUMOR-GROWTHIN-VIVO

Our previous studies demonstrated that matrix metalloproteinase (MMP-9 ) levels were significantly higher in human glioblastoma tissue sample s than in low-grade brain tumors and normal brain tissue (Rao et al., Cancer Res. 53, 2208-2211, 1993). In the present study, we measured th e levels of MMP-2 and MMP-9 during the growth of glial tumors in nude mice by intracerebral injection of glioblastoma cells. Using gelatin z ymography, densitometry, and an enzyme-linked immunosorbent assay, we found that the enzyme activity and protein count of MMP-2 and MMP-9 we re a respective 3- to 10- and 2- to 30-fold higher in tumors at day 14 and 28 than in normal tissue. Immunohistochemical staining for MMP-9 showed strong immunoreactivity in tumor cells and the staining intensi ty was much higher at day 28, compared to day 14. These results sugges t that upregulation of MMP-9 plays a major role in the glioma tumor gr owth in vivo. (C) 1998 Academic Press.