Figure 6. PI-103 is cytotoxic to primary lymphoblasts from pediatric patients with T-ALL, displaying constitutive phosphorylation of AKT and 4E-BP1 and induces caspase-3 activation.
A: Samples from T-ALL patients were analyzed by flow cytometry for the levels of Ser 473 p-Akt and Thr 37/46 p-4E-BP1. Four representative patients are shown. Black histograms: negative control (irrelevant Ab); grey histograms: cells positive for the specific Ab. B: Patient samples were analyzed by flow cytometry for the levels of Ser 473 p-Akt prior to (CTRL) and after treatment with PI-103 (0.5 µM for 72 h). Black histograms: negative control (irrelevant Ab); grey histograms: cells positive for the specific Ab. C: Patient samples were treated with 0.1 µM rapamycin or 0.5 µM PI-103 or DMSO for 72 h, then analyzed by flow cytometry for cleaved caspase-3. Black histograms: DMSO-treated samples; grey histograms: drug-treated samples. D: MTT assay of TALL blasts treated with PI-103 for 96 h. Results are the mean of at least two different experiments ± SD, and asterisk indicates statistically significant difference (p<0.0001) with respect to untreated cells. Four representative patients are shown.