Figure 4

U0126, a MEK inhibitor, potentiates the anticancer efficacy of ATP-competitive inhibitors of mTOR in vitro. A: LS174T cells (left panel) or SW480 cells (right panel) were treated with rapamycin (R, 10 nM), NVP-BEZ235 (N, 100 nM), PP242 (P, 100 nM) or DMSO as a control (C) for 4 hours. Cells were subsequently lysed and lysates were analyzed by Western Blot for phospho-MAPK and MAPK. The illustrated blots are representative of three independent experiments. B: LS174T and SW480 colon cancer cells were treated with rapamycin (R, 10 nM), NVP-BEZ235 (N, 100 nM) or PP242 (P, 100 nM) for 48 hours in combination or not with U0126 (10 μM). Cell proliferation was assessed by BrDU incorporation. Results are quantified as percentage of positive cells for BrdU incorporation. Columns, mean percentage of three independent experiments; bars, SD C: Cells were processed as under panel B and cell apoptosis was evaluated using a cell death detection ELISA. Cells were harvested and apoptosis was measured by quantifying DNA fragmentation. Columns, mean enrichment factor at 405 nm of three independent experiments; bars, SD.