Fig. 5.

Imetelstat reduced self-renewal and tumorigenicity of pediatric ependymoma cells. a Colony forming assay showed Imetelstat progressively inhibited the self-renewal of R254 ependymoma cells, with complete inhibition by week 17 of treatment. b Sphere-forming assay showed a 75 % increase of cells required to be seeded to generate at least one sphere in each of four wells following 34 weeks of treatment. c Kaplan–Meier survival analysis showed mice injected supratentorially with Imetelstat-pretreated E520 cells (34 weeks) were asymptomatic at 90 days while mice injected with untreated E520 cells all required killing by day 60 (n = 7/group). Upon pathological analysis, all mice injected with untreated cells possessed tumors (d), while no mice injected with Imetelstat-pretreated cells showed evidence of neoplastic growth (e). Images were captured at 40× magnification with 200× inlets shown in bottom left corners. Student’s t test was used to determine significance in a and b while log-rank statistics were used to test significance in c. Error bars represent ± SD of triplicates