Fig. 1: Treatment with the MEKi selumetinib or trametinib significantly impedes UI226 SHH MB tumorigenic properties in vitro.

A, B Western blot for p-ERK1/2, total ERK1/2 and GAPDH following treatment of UI226 SHH MB tumorspheres with selumetinib (A) or trametinib (B) for 3 days. Total ERK 1/2 and GAPDH served as loading controls. C, D Representative images of UI226 tumorspheres following treatment with various concentrations of selumetinib (C) or trametinib (D). Scale bar: 400 µm. E, F UI226 tumorsphere size following treatment with increasing doses of selumetinib (E) or trametinib (F). Error bars: SEM. N = 5 biological replicates and n = 4 technical replicates for each biological replicate. Statistical analysis was completed using the Kolmogorov–Smirnov test. ****, p < 0.0001. G, H UI226 tumorsphere number following treatment with increasing doses of selumetinib (G) or trametinib (H). Error bars: SEM. N = 5 biological replicates and n = 4 technical replicates for each biological replicate. Statistical analysis was completed using the Dunnett’s test for multiple comparisons. *, p < 0.05. For g: DMSO vs. 20 μM, p = 0.0291. I, J UI226 cell viability following treatment with increasing doses of selumetinib (I) or trametinib (J). Error bars: SEM. N = 5 biological replicates and n = 4 technical replicates for each biological replicate. Statistical analysis was completed using the Dunnett’s test for multiple comparisons. *, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, p < 0.0001. For I: DMSO vs. 10 μM, p = 0.0198; DMSO vs. 20 μM, p = 0.0025. For J: DMSO vs. 250 nM, p = 0.0012; DMSO vs. 500 nM, p = 0.0030; DMSO vs. 1 μM, p < 0.0001. K UI226 migration following treatment with increasing doses of trametinib. Error bars: SEM. N = 3 biological replicates and n = 4 technical replicates for each biological replicate. Statistical analysis was completed using the Dunnett’s test for multiple comparisons. *, p < 0.05; **, p < 0.01. DMSO vs. 500 nM, p = 0.0161; DMSO vs. 1 μM, p = 0.0047.