FIGURE 7.

ERK activation is a mechanism of resistance to pp242. In A (viable recovery) and B (apoptosis), 8226 or MM1.S cells treated ± U0126 (at 0 (circles), 250 (squares), 1000 (triangles), or 5000 (diamonds) nm) ± pp242 (at 100, 250, or 500 nm). Viable recovery (A) and % apoptosis (B) then assayed after 72 h for 8226 cells and 48 h for MM1.S cells, Viable recovery reported as percent of control (no drug treatment), mean ± S.D. (n = 4). Apoptosis reported as mean percent cells positive for activated caspase 3 expression over control by FACs analysis (n = 3). The SDs were all <5% of the means. In C, MM1.S cells similarly treated with pp242 at 100, 250, or 500 nm ± CI1040 at 250, 1000, or 2000 nm and apoptosis (mean of three separate experiments) evaluated by flow cytometry for annexin-V-positive cells. The SDs were all <5% of the means.