Fig. 2

Nelarabine induces apoptosis in a group of sensitive T-ALL cell lines and modulates PI3K/AKT/mTOR and MEK signaling. a Flow cytometric analysis of Annexin V-FITC/PI stained T-ALL cells treated with nelarabine (5 μM for JURKAT, P12-ICHIKAWA, and DND-41 cells, 2 μM MOLT-4 cells) 48 h. The percentages of early apoptotic cells (Annexin-V FITC⁺/PI⁻; bottom right quadrant) and late apoptotic/necrotic cells (Annexin-V FITC⁺/PI⁺; top right quadrant) are plotted. The histograms are representative of three separate experiments. CTRL untreated cells. b Western blot analysis documenting cleavage of caspase-8, caspase-9, caspase-3, and PARP by nelarabine. Cells were treated with nelarabine (5 μM for JURKAT, P12-ICHIKAWA, and DND-41 cells, 2 μM MOLT-4 cells) for the indicated times, collected, and then lysed. Fifty micrograms of each lysate were electrophoresed on SDS-PAGE gels followed by transfer onto a nitrocellulose membrane. c Nelarabine induces a decrease in the phosphorylation status of critical components of the PI3K/AKT/mTOR signaling pathway, as well as p-ERK (Thr202) levels in T-ALL sensitive cell lines. Western blot analysis documenting the reduction of p-AKT (Ser473), p-S6RP, p-GSK3β (Ser9), and p-ERK (Thr202). Antibody to β-actin served as a loading control. Molecular weights are indicated on the right