AF6 controls RAS-GTP levels and RAS downstream pathway. (A) WB analyses of the RAF/MEK/ERK pathway after silencing of MLL-AF6 in ML2 and SHI-1 cell lines: a decreased level of phosphorylation for c-RAF, MEK1/2, and ERK1/2 is visible compared with negative controls (scRNA); anti-ACTIN was used as control for total protein amount. (B) (Top) A decrease in colony formation (percentage with respect to scRNA) on semisolid medium. (Bottom) An increase in apoptosis (Annexin and propidium iodide-positive cells) in ML2 and SHI-1 cell lines after MLL-AF6 silencing (siMLL-AF6) compared with scRNA are observed (n = 3; P < .05). (C) Treatment of ML2 and SHI-1 cells with PD98059 (40 µM). WB analysis shows p-ERK1/2 reduction after treatment. Anti-ACTIN was used as a positive control of protein amount. (D) (Left) An increased apoptosis and (right) a decreased percentage of colony formation is measured after treatment with PD98059 compared with negative controls treated with dimethylsulfoxide (n = 2). *P < 0.05.