Figure 7.

Overexpression of Mettl3 or Mettl14 attenuates DLL-mediated tumor-infiltrating CD8+ T cells and cytokine production. (a) Mice bearing control and Mettl3 or Mettl14 overexpressed tumors were treated with IFN-γ blocking antibody and DLL as indicated. Tumor volume was measured over time points. The inhibitory effects of DLL on tumor growth were reversed by Mettl3 or Mettl14 overexpression or IFN-γ blocking antibody treatment. (b) Percentage of tumor-infiltrating T cells and Treg cells were identified by flow cytometry from 3LL tumors as indicated. (c) Representative images of CD8 by IHC staining. Tissue sections from BALB/c mice bearing the indicated treatments. DLL-promoted CD8+ T infiltration was reversed by Mettl3 or Mettl14 overexpression or IFN-γ blocking antibody treatment. Scale bars, 200 μm. (d) IFN-γ production in intratumor from BALB/c mice by ELISA. DLL-promoted IFN-γ secretion was reversed by Mettl3 or Mettl14 overexpression or IFN-γ blocking antibody treatment. (e–i) Quantitative RT-PCR was performed to identify transcriptional changes in the IFN-γ response gene expression. DLL-enhanced Stat1, Irf1, CLL5, CXCL9, and CXCL10 levels were reversed by Mettl3 or Mettl14 overexpression or IFN-γ blocking antibody treatment. (j) The representative images of ROS in tumor. DLL-promoted ROS products were reversed by Mettl3 or Mettl14 overexpression or IFN-γ blocking antibody treatment. (k–m) ELISA was performed to measure the concentration of ROS, SOD, and GPX in tumor tissues. DLL-enhanced ROS levels and DLL-reduced SOD and GPX levels were reversed by Mettl3 or Mettl14 overexpression or IFN-γ blocking antibody treatment. Data are the mean ± SD from three independent experiments. ^∗P < 0.05 by Student's t-test, N = 6. DLL: delicaflavone.