Fig. 7: Pharmacological inhibition or genetic deletion of FASN abrogates the effect of METTL3 ablation on tumor progression.
a The knockout efficiency of FASN and METTL3 in WT, Mettl3fl/flLyz2Cre and Mettl3fl/flFasnfl/flLyz2Cre BMDMs was analyzed by western blot. (n = 3 independent experiments). b, c Representative images of tumors in WT, Mettl3fl/flLyz2Cre and Mettl3fl/flFasnfl/flLyz2Cre mice implanted with GL261 cells (b) on day 21 and representative HE staining images of brain sections (c) are shown. The tumor area was quantified (c). (n = 6 mice per group). d Representative plots and percentages of IFN-γ-producing CD8+ T cells cocultured with WT, Mettl3fl/flLyz2Cre and Mettl3fl/flFasnfl/flLyz2Cre BMDMs. (n = 5 independent experiments). e, f Representative bioluminescent images of Mettl3fl/fl or Mettl3fl/flLyz2Cre mice bearing orthotopic murine glioma GL261 cell xenografts treated i.p. with vehicle or C75 (e) and bioluminescent signal was quantified (f). (n = 6 mice per group). g Representative HE staining images of brain sections from orthotopic GL261 murine glioma-bearing mice on day 21 post-xenograft, following intraperitoneal treatment with vehicle or C75. The tumor area was quantified. (n = 6 mice per group). h Lymphocytes were cocultured with WT and Mettl3fl/flLyz2Cre BMDMs treated with vehicle or C75 and percentages of IFN-γ-producing CD8+ T cells were quantified. Scale bars: 50 μm. (n = 4 independent experiments). i Immunofluorescence staining for METTL3, ISG15 and FASN in sections from patients with glioma tumors. Quantitative image analysis was performed. Scale bars: 30 μm. (n = 3 independent experiments). j Quantitative image analysis revealed that lower METTL3 levels in CD68⁺ macrophages are strongly and independently associated with diminished overall survival. k Schematic illustrating the mechanism by which METTL3-deficient macrophages promote glioma progression through ISG15-FASN axis-mediated reprogramming of lipid metabolism. Data are expressed as the mean ± SD. P values were determined by one-way ANOVA with Tukey’s multiple comparisons (c, d, f, g, h) and the Gehan-Breslow-Wilcoxon test (j). The source data are provided as a Source data file.
