Figure 5

ERK activity is transiently increased at 20 min and p38 kinase activity is increased at 20 and 30 min post-treatment with TIMP-1 or GM6001. Kinase activity assays were performed as described in Materials and Methods. The Western blots shown in panel (A) indicate the level of ERK activity associated with MDA-MB-435 cells. The bands are phosphorylated recombinant Elk-1, which was phosphorylated by ERK immunoprecipitated from MDA-MB-435 cells. The first two lanes of each treatment set represent samples taken at 20 min post-treatment and the second two lanes of each treatment set represent samples taken at 30 min. Control and treated samples alternate as indicated in the figure. Densitometry data for the ERK activity assay are shown in panel (B). They indicate a two-fold increase in ERK activity for both TIMP-1 and GM6001 at 20 min relative to an untreated control. Panel (C) shows the level of p38 kinase activity as measured by recombinant ATF-2 phosphorylated by immunoprecipitated p38 kinase from MDA-MB-435 cells. Panel (D) shows densitometry data for p38 kinase assays. There is a clear two-fold increase in p38 kinase activity for all three treatments relative to an untreated control.