Figure 3.

M1-like TAMs inhibit tumor growth by multiple mechanisms. (A, left) Tumor weight from GIST mice treated with α-CSF1R for 4 wk. Red triangles represent mice depleted <50% of control group median (horizontal bars; Fig. 2 D). (A, right) Tumor weight excluding mice that were not depleted after α-CSF1R treatment. Shown are composites of two to three experiments per time point (n = 7–17 mice per group). (B) Tumor weight after PLX5622 therapy. Composite of two experiments per time point, 6–10 mice per group. (C) Live CD45⁻KIT⁺ cells by trypan blue exclusion after 4 wk of therapy. Only depleted mice are shown for α-CSF1R. Composite of two experiments, 7–12 mice per group. (D) Cell viability at 72 h of co-culture of S2 cells with TAMs from untreated GIST mice. 5 × 10³ S2 cells were plated in a flat-bottom 96-well plate either alone or with TAMs in various ratios. After 72 h, wells with S2 cells alone were fully confluent. Cell viability was assessed by optical density at 450 nm (OD450). Shown is a representative of two experiments, with measurements in at least triplicate. (E) Splenic T cells from untreated GIST mice were cultured in α-CD3–coated plates with various ratios of TAMs from GIST mice. Proliferation at 72 h (left) or supernatant IFN-γ at 48 h (right) were measured. Representative of at least three experiments. Cpm, counts per minute. x indicates a single replicate of that dilution. TAMs alone did not produce IFN-γ (not depicted). (F) After 4 wk of treatment with PLX5622, intracellular IFN-γ was measured in tumors and mesenteric lymph nodes. Shown is a representative of two experiments, total 10–11 mice/group. (G) Splenic T cells were cultured in α-CD3–coated plates with various ratios of TAMs from S2 or B16 flank tumors, and proliferation was measured at 72 h. Shown is a representative of two experiments in at least triplicate. (H) S2 cell flank tumor volume after treatment with PLX5622 (n = 5–10 mice/group). Bar and line graphs show mean ± SEM. *, P < 0.05.