Fig. 3: In vivo antitumor activity of STEAP1-BBζ CAR T cell therapy in prostate cancer models with native STEAP1 expression.
a Volumes of 22Rv1 subcutaneous tumors in NSG mice (n = 4 for untransduced T cells group and n = 5 for STEAP1-BBζ CAR T cells group) over time after a single intratumoral injection of 5 × 106 untransduced T cells or STEAP1-BBζ CAR T cells at normal CD4/CD8 ratios. p < 0.0001 at day 20 and 25. Bars represent mean with SEM. b Schematic of tumor challenge experiments for 22Rv1 (top) and C4-2B (bottom) disseminated models. fLuc firefly luciferase, BLI bioluminescence imaging. c Serial live bioluminescence imaging (BLI) of NSG mice engrafted with 22Rv1-fLuc metastases and treated with a single intravenous injection of 5 × 106 untransduced T cells or STEAP1-BBζ CAR T cells at normal CD4/CD8 ratios on day 0. Red X denotes deceased mice. Radiance scale is shown. d Plot showing the quantification of total flux over time from live BLI of each mouse in (c). e Kaplan–Meier survival curves of mice in (c) with statistical significance determined by log-rank (Mantel-Cox) test. For panels (c–e) n = 5 mice per condition were used. f Serial live BLI of NSG mice engrafted with C4-2B metastases and treated with a single intravenous injection of 5 × 106 untransduced T cells or STEAP1-BBζ CAR T cells at normal CD4/CD8 ratios on day 0. Red X denotes deceased mice. Radiance scale is shown. g Plot showing the quantification of total flux over time from live BLI of each mouse in (f). For panels (f, g) n = 4 mice were used in the untransduced T cells group and n = 5 mice in the STEAP1-BBζ CAR T cells group. h Quantification of CD3+EGFRt+ STEAP1-BBζ CAR T cells by flow cytometry from splenocytes of mice treated with STEAP1-BBζ CAR T cells (n = 4) at the end of experiment on day 49. Bars represent mean. For panel (a), two-way ANOVA with Sidak’s multiple comparison test was used. Source data are provided in the Source Data file.
