FIGURE 5 from D-2-HG Inhibits IDH1^mut Glioma Growth via FTO Inhibition and Resultant m6A Hypermethylation

Pharmacologic inhibition of FTO using FB23-2 reduces tumor growth rates in intracranial IDH1wt gliomasphere xenografts. A, Pharmacokinetic analysis of FB23-2 permeability through the BBB showing drug elimination dynamics in plasma and brain (2 mice/timepoint). B, Schematic of in vivo experiments whereby intracranial gliomasphere xenografts were established before undergoing randomization to daily intraperitoneal injections of either FB23-2 treatment or DMSO control, with injection volumes based on individual weights (20 mg/kg). In vivo monitoring of tumor growth measured via plasma Gaussia Luciferase activity (tail vein) revealed differences at 7–8 weeks (GS187) and 6–7 weeks (XDS4130; at week 8, only 1 mouse remained in DMSO group), respectively [ANOVA, (C) treatment: F(1,16) = 4.7, P ≤ 0.05; time: F(7,106) = 79.1, P ≤ 0.0001; interaction: F(7,106) = 4.3, P ≤ 0.0003; (D) treatment: F(1,18) = 16.7, P ≤ 0.0007; time: F(1.6,23.6) = 41.7, P ≤ 0.0001; interaction: F(7,104) = 5.3, P ≤ 0.0001; asterisks indicate post hoc Newman–Keuls on day 7 and 8]. Kaplan–Meier curves showing overall survival differences in xenograft mice treated with FB23-2 (3 µmol/L) or DMSO control, evaluated via a log-rank (Mantel–Cox) test for GS187 (E, P < 0.005) and XDS4130 (F, P ≤ 0.05). G, Activated Cas3 immunostaining (G, 10X magnification) of representative XDS4130 xenografts (surgically extracted and flash-frozen post-mortem). “MS” refers to the mouse identification number. H, Increase in number of Cas3 positive cells in tumors from mice treated with FB23-2 relative to DMSO controls (P ≤ 0.005). *, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001; and ****, P ≤ 0.0001 compared with relevant controls. Unless otherwise stated, P values indicate unpaired Student t test comparisons with the control, or between two groups as indicated by the horizontal line.