OTSSP167 induces cell death in T-ALL cell lines. (A) Representative flow cytometric analysis of annexin V staining for KOPT-K1 and ALL-SIL cell lines (15 nM OTSSP167, 48 hours). (B) Percentage of annexin V–positive cells upon OTSSP167 treatment (15 nM, 48 hours) is shown for all cell lines (n=3). The data represent 3 independent experiments and the mean and standard deviation. (C) Immunoblot analysis of cleaved PARP and caspase 3 in T-ALL cells treated with vehicle or 15 nM OTSSP167 for 48 hours. (D) Proteomic analysis by RPPA phase showing deregulation of proapoptotic proteins induced by treatment of KOPT-K1, MOLT-3, and P12-Ichikawa cell lines with OTSSP167 (15 nM, 48 hours). ∗ P < .05, ∗∗P <. 01, ∗∗∗P < .001 (two-tailed Student t test).