Fig 1: PD analysis of POx-Palbo in medulloblastoma-bearing G-Smo mice.(A) Kaplan-Meier curve of POx-Palbo treatments (#1 to #3) and Palbo-HCl in G-Smo mice. (B) H&E of POx-Palbo–treated brains at 24 hours (P11) and five daily treatments (P15) compared to saline controls. (C) Two-dimensional flow cytometry analysis of DNA content (x axis) and pRB content (y axis) in POx-Palbo–treated (2 to 24 hours) G-Smo mice, quantifying pRB++ cells at G1. (D) Quantification of pRB++ cells in G1 (red square) in POx-Palbo–treated mice. P values were determined using one-way analysis of variance (ANOVA). (E) Uniform manifold approximation and projection (UMAP) qualitative map of tumor cells dissociated from G-Smo mice. (F) Cell cycle analysis of tumor cells in G-Smo mice at indicated intervals after treatment with POx-Palbo (25 mg/kg). P values were determined by comparisons of each cell cycle phase at each time point versus saline control using one-way ANOVA. (G) Quantification of pRB++ cells at G1 in POx-Palbo (25 mg/kg)–treated G-Smo mice after 5 days. Statistical analysis was performed with one-way ANOVA. (H) Longitudinal analysis of BLI G-SmoGli-Luc mice with indicated treatment, quantified in the right panel. *Mouse died before 72-hour imaging. In (A, D, F, and G), *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001. A.U., arbitrary units.