OTSSP167 induces G2/M cell cycle arrest in T-ALL cell lines. (A) Representative flow cytometric analysis of DNA content (propidium iodide) of KOPT-K1 and DND-41 cell lines treated with vehicle or 15 nM OTSSP167 for 48 hours. (B) Effect of OTSSP167 treatment on the distribution in cell cycle phases in a panel of T-ALL cell lines (n=3). (C) Immunoblot analysis of regulators of the G2/M cell cycle checkpoint. (D) Heatmap showing alterations in the G2/M checkpoint by RPPA. (E) Immunoblot analysis of G2/M checkpoint regulators. ∗ P < .05, ∗∗P < .01, ∗∗∗∗P < .0001 (two-tailed Student’s t test).