MMP inhibitory activity of PEG_20K-TIMP-1 in fibroblast cultures and orthotopic tumors.

<p>(A) <i>In situ</i> zymography of mammary fibroblast cultures developed with (right panel) or without (left panel) 500 nM PEG_20K-TIMP-1 show decreased gelatinase activity in the treated cells, as indicated by a reduction in green fluorescent signal produced by cleavage of quenched fluorescent substrate DQ-gelatin. (B) <i>In situ</i> zymography of tumor sections from mammary tumor-bearing mice injected 24 hours prior to sacrifice with saline (left) or 2 mg/kg PEG_20K-TIMP-1 (right) show reduced gelatinase activity in the tumor from the mouse receiving PEG_20K-TIMP-1.