Figure 1. The PI3K/Akt pathway is constitutively hyperactivated in primary T-ALL cells.

(A) Cell lysates of normal human thymocytes or primary T-ALL cells collected at diagnosis and immunoblotted with the indicated phosphospecific antibodies or actin as loading control. (B) Levels of phosphorylated Akt (S473) in thymocyte (n = 8) and T-ALL (n = 15) samples were quantified by densitometry analysis. Points represent individual samples, horizontal bars denote mean, and mean ± SEM is shown in parentheses. (C) Surface expression of PIP3 was determined by confocal microscopy after staining with anti-PIP3 antibody. Scale bar: 50 μm. Insets (20 μm square) of 1 representative cell of each sample are shown. (D) Same samples were analyzed by flow cytometry. Values in each histogram indicate PIP3 mean fluorescence intensity; gray histogram represents negative isotypic control; vertical lines indicate peak value in T-ALL samples. (E) Mean fluorescence intensity (MFI) was quantified by flow cytometry and compared in thymocyte and T-ALL samples (n = 4 per group). Values are mean ± SEM.