Fig. 5: IDO1 promoted m6A methylation via AhR-mediated transcriptional inhibition of the FTO gene.

A Western blotting was used to detect the expression of m6A regulators in U87 and LN229 cells with IDO1 overexpression (n = 3 biologically replicates). B Western blotting was used to detect the expression of IDO1 and AhR in U87 cells with IDO1 overexpression (n = 3 biologically replicates). C IF was used to visualized subcellular distribution of AhR in U87 cells with IDO1 overexpression. scale bar = 20 μm or 5 μm. D Western blotting analysis of the expression of AhR in total, cytoplasmic (Cyt), and nuclear (Nuc) protein samples of U87 cells with IDO1 overexpression. Cytoplasmic GAPDH and nuclear Lamin B1 were used as controls for normalization (n = 3 biologically replicates). E Correlation between the expression of FTO and AhR in clinical GBM samples was analyzed by transcriptome profiling in the TCGA glioblastoma database. F Predicted FTO binding motifs (CGTG) were obtained using the JASPAR public database. G Schematic diagram of potential AhR binding sites in the promoter region of FTO, and ChIP-qPCR analysis was used to detect the enrichment of AhR on FTO promoter (n = 3 biologically replicates). H Western blotting was used to evaluate the protein levels of IDO1, AhR, FTO, SLC7A11 after AhR knockdown in IDO1 overexpressed U87 cells (n = 3 biologically replicates). I Western blotting analysis of the expression of SLC7A11 in U87-WT cells treated with different concentrations of Kyn for 48 h (n = 3 biologically replicates). The data are represented as the mean ± standard deviation (SD); *p < 0.05, **p < 0.01, ***p < 0.001, ns, not significant.