Fig. 2
Exosomal miR-125b-5p sensitizes anti-PD-1 therapy in murine colon tumor model by increasing tumor-infiltrating CD8 CTLs and reducing Tregs. C57BL/6J mice were subcutaneous (s.c.) inoculated with MC38 tumor cells to the right flank of each mouse on day 1, then randomly divided into four groups. When tumor size reached ~100 mm3, mice were treated by injection of MSC-EXO-miR-125b-5p into tail veil with or without anti-PD-1 antibody (i.p., 100 µg/mouse) every three days for two weeks. The control group was defined by administered MSC-EXO-miR-NC and IgG. The immune cells in tumor tissue were examined by gating on live cells with flow cytometry. (A) The tumor growth curve was plotted from each group (n = 10). (B) Survival curve (Kaplan-Meier plotter). Summary of the ratio of CD8 versus CD4 T cells (C), and Ki67 expression by CD8 T cells (D) were shown. Typical FACS plot (E) and summary (G) of IFNγ-expressing CD8 T cells were shown. Representative flow cytometric plot (F) and summary (H) of the percentage of Foxp3+ Tregs in CD4+ T cells in mouse tumor tissues. For typical FCM plots, the number indicated the proportion of gated cells. The summarized data shown were represented as mean ± SD, n = 5 mice of each group. The results data in A and B were pooled from two independent experiments (n = 10). By comparison with the control group, *, P < 0.05, ** P < 0.01, *** P < 0.001