Extended Data Fig. 4. 4C4 deletions dictate the response to immune checkpoint blockade.
(A) Waterfall plot of percentage of tumor volume change. Tumors were measured at baseline and 14 days after treatment with vehicle, Combo (MEK and CDK4/6 inhibitors), α-PD1, or Combo + α-PD1. Each bar represents an independent biological replicate (n = 8-9 per group). (B) Experimental setup to assess immune infiltration in ΔS and ΔL tumors before onset of necrosis. (C) (Left) Frequency of CD11B + cells; (Right) Median PD-L1 surface expression of CD11B + cells in ΔS and ΔL tumors treated with vehicle or Combo+PD1. Differences were assessed Differences were assessed with one-way ANOVA followed by Sidak’s multiple comparison between vehicle and Combo+PD1 treated tumors (ΔS vehicle n = 5, ΔS treated n = 10, ΔL vehicle n = 4, ΔL treated n = 9 independent mice per condition). (D) Frequency of CD4 T cells (CD3e + CD4 + ) in ΔS and ΔL tumors treated with vehicle or Combo+PD1. Differences were assessed with one-way ANOVA followed by Sidak’s multiple comparison between vehicle and Combo+PD1 treated tumors (ΔS vehicle n = 5, ΔS treated n = 10, ΔL vehicle n = 4, ΔL treated n = 9 independent mice per condition). (E) (Left) Frequency of CD8 T cells (CD3e + CD8 + ); (Right) Median PD1 surface expression of CD8 T cells in ΔS and ΔL tumors treated with vehicle or Combo+PD1. Differences were assessed with one-way ANOVA followed by Sidak’s multiple comparison between vehicle and Combo+PD1 treated tumors (ΔS vehicle n = 5, ΔS treated n = 10, ΔL vehicle n = 4, ΔL treated n = 9 independent mice per condition). (F-I) Frequency of the indicated cell types in ΔS’ and ΔL tumors treated for one week with vehicle or α-CTLA4 condition). (F) CD4 T cells (CD3e + CD4 + ); (G) CD11B + cells; (H) (Left) Dendritic cells (CD11C + MHCII + ), (Right) CD11B + DCs (CD11C + MHCII + CD11B + CD103-); (I) TAMs (CD11B + CD11C- Ly6G- Ly6C- F4/80 + ). Differences were assessed with one-way ANOVA followed by Sidak’s multiple comparison between vehicle and α-CTLA4 (ΔS vehicle n = 7, ΔS treated n = 6, ΔL vehicle n = 7, ΔL treated n = 7 independent mice per condition).