Fig. 6

Association of tumor-infiltrating activated T cells with MDSCs in patients with CRC. a Representative plot and statistical analysis of IFN-γ and TNF-α levels in TRAIL⁺ or TRAIL⁻ T cells isolated from freshly resected CRC tissues (n = 5). b The mRNA levels of DR1–DR5 in CD11b⁺ myeloid cells that were purified from non-tumor and tumor regions of CRC tissues were examined by qPCR (n = 8). c Representative plot and summary of FACS analysis of DR5 expression on PMN-MDSCs and M-MDSCs from paired non-tumor and tumor regions of CRC tissues (n = 6). d, e FACS and immunofluorescence were used to analyze the association of the intra-tumoral apoptotic MDSC frequency with TRAIL⁺ T-cell number. Annexin V⁺ MDSCs and cleaved-Caspase 3⁺ MDSCs both represented apoptotic MDSCs (n = 8). f CD11b⁺ myeloid cells isolated from CRC tissues were treated ex vivo with ASN, type I interferons and TNF-α, or DMEM for 2 days and then cocultured with CFSE-labeled T cells. FACS was used to examine the proliferation of T cells. (n = 3). g, h Frequencies of TRAIL⁺ T cells in the CRC organoid model after anti-PD-1 therapy were quantified using FACS (g) and immunofluorescence (h). The data shown are from five CRC samples that showed a response to anti-PD-1 treatment. i Representative plot and statistical analysis of DR5 expression in Annexin V⁺ or Annexin V⁻ MDSCs. The data are from five responders to PD-1 blockade therapy. The data are shown as the mean ± SEM. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001