Figure 2. CAR T cell therapy treats heterogeneous ovarian tumors.
(a) Expression of the NKG2D ligand Rae1 on sorted ID8/GFP-shRae1 cells (black unfilled; MFI 17), ID8/RFP cells (black filled; MFI 89), and isotype control cells (gray unfilled; MFI 10). (b) Lysis of target ID8/GFP cells (unfilled triangle) or ID8/GFP-shRae1 cells (filled square) by effector chNKG2D T cells or lysis of ID8/GFP cells by wtNKG2D T cells (unfilled square) is shown for three different effector to target ratios. (*, p < 0.05 vs. wtNKG2D + ID8/GFP; †, p < 0.05 vs. chNKG2D + ID8/GFP-shRae1). (c) IFN-γ production by wtNKG2D or chNKG2D T cells stimulated with media or irradiated RMA, ID8, or ID8/GFP-shRae1 tumor cells was measured. Differences between groups were analyzed by Student’s t-test (***, p < 0.001 vs. media). (d) Mice (10–12 per group) were injected with 106 ID8/GFP-shRae1 cells, ID8/RFP cells, or a 1:1 mixture of both. The mice receiving the 1:1 tumor mixture received the same number (106 cells) of each tumor type as each single tumor control, which was double the total tumor cell inoculum. On weeks 5, 7, and 9 tumor-bearing mice were treated with 5 × 106 chNKG2D or wtNKG2D T cells. The number of solid tumors and tumor cells in the ascites was assessed on week 12 (***, p < 0.001 vs. RFP+WT; †, p < 0.001 vs. RFP+CH). (e) The number of RFP (Rae1+) and GFP (Rae1−) tumor cells in the ascites of mice bearing 1:1 mixed tumors was assessed. (f) Mice (6–12 per group) were injected with 2 × 106 ID8/GFP-shRae1 cells, ID8/RFP cells, or a 4:1 or 13:1 (ID8/GFP-shRae1: ID8/RFP) mixture of both. Mice were treated with 5 × 106 chNKG2D or wtNKG2D T cells on weeks 5, 7, and 9. Mice were sacrificed twelve weeks post-tumor inoculation and the number of solid tumors was assessed. Differences between groups were analyzed by ANOVA and Newman-Keuls post test. (***, p < 0.001; *, p < 0.05 vs. ID8/RFP (+ chNKG2D T cells); †, p < 0.001 vs. shID8/GFP (+ chNKG2D T cells) and ID8/RFP).