γ-secretase inhibition for 5 to 7 days with compound E reduces proliferation in the Mino, Rec-1, and SP-49 cell lines. (A) Cells were incubated in triplicate with 1μM of compound E or mock, and proliferation was assessed by flow cytometry after EdU incorporation and staining with AlexaFluor-488 azide. *Statistical significance at the .05 level (2-sided t test). Error bars represent SD. (B) Cell-cycle analysis of the Rec-1 and SP-49 cell lines after γ-secretase inhibition. In addition to detection of EdU incorporation with AlexaFluor-488 azide, cells were stained with FxCycle Far Red. Labels indicate mean percentages of cells in given populations.