MT1-MMP activity is inhibited by TIMP-3.
(A) Direct assay of MT1-MMP activity. Confluent hMVECs were incubated with 108 pfu/mL adenovirus in M199/0.1% human serum albumin, ie, AdPC10 (Ad.Contr), Ad.TIMP-1, or Ad.TIMP-3. MT1-MMP activity was assayed in cell extracts as described in “Materials and methods.” The data represent the mean ± range of 2 independent cultures. (B) Inhibition of MMP-2 activation by TIMP-3. Confluent HUVECs were incubated with 108 pfu/mL AdPC10 (AdCtrl), AdTIMP-1, or AdTIMP-3. After 2 hours the media were removed and cells were incubated overnight with culture medium. Thereafter, cells were washed with M199 containing 0.03% human serum albumin to remove serum components and incubated with this media containing no stimulus or 10 ng/mL PMA. After 48 hours the conditioned media were collected and gelatin zymography was performed as described. The same results were observed in 4 different experiments.
