Fig 4.

Cooperative inhibition of EGFR and mTOR are critical to arrest growth of PTEN^mt human glioma cells. (A) U87:EGFR (PTEN^mt) cells were treated with erlotinib, PIK-90, rapamycin, PI-103, erlotinib plus PIK-90, erlotinib plus rapamycin, PIK-90 plus rapamycin, or erlotinib plus PI-103 at dosages indicated. Viable cells were measure by WST-1 assay after treatment for 72 hr. Error was calculated among triplicate measurements (top panel). Flow cytometry analysis (bar graph-bottom panel) shows effects on cell cycle after treatment for 24 hr. Percentage of cells in G₀G₁, S, and G₂M phases of the cell cycle is indicated. (B) Cells were treated as in (A). EGF was added 15 min prior to harvest. Lysates were subjected to immunoblot analysis with antisera indicated.