Figure 6.
Inducible IL-12 Release Augments Antitumor Activity of CAR T Cells in a GC Peritoneal Tumor Model
(A) Schematic diagram of the lentiviral vector encoding inducible IL-12. The expression of ICAM-1 CAR is driven by the EF1α promoter, while IL-12 expression is under the transcriptional control of a synthetic NF-κB-NFAT promoter. (B) GFP expression in Jurkat CAR/GFP T cells after coculture for 24 h with 293T cells with or without human ICAM-1 (hICAM-1) expression. CAR expression was estimated by staining with an anti-SSTR2 antibody. (C) IL-12 release by Jurkat CAR/IL-12 T cells after coculture with 293T cells with or without human ICAM-1 expression, or with the addition of PMA and ionomycin to media, measured in duplicate (mean ± SD). (D) Comparison of target cell lysis by CAR T (CP9) and CAR/IL-12 T cells during 24 h at an E:T ratio of 1:1. Data represent mean ± SD (n = 4; unpaired, two-tailed t test; ∗∗∗∗p < 0.0001; ns, not significant). (E) Whole-body bioluminescence images of NSG mice xenografted with 0.5 × 106 SNU-638 (two independent experiments, n = 6–7 per cohort). (F) Quantitation of bioluminescence intensity over time (n = 6–7 per cohort). Each line represents data for each individual mouse. (G) Cytokine levels in the plasma were measured from the blood collected at 2, 3, and 6 weeks post-xenograft. Data represent mean ± SD (n = 1–2).