Figure 2.

Determining the ideal CAR-T cell dose combined with radiation for mice bearing subcutaneous GSU gastric carcinoma tumors. (A) In an efficacy study using the GSU tumor model, if the radiation was given in one fraction (each radiation fraction is indicated by a yellow arrow) on day 8 (4Gy) post-tumor implantation, the infusion was administered on day 9 (dark green); if the radiation included four doses (1Gy in 4 fractions) on days 8, 9, 10, and 11, the mice received the infusion 24h after the last fraction on day 12 (light green). In a single experiment, we included two doses of CAR-T cells combined with two dose regimens of radiotherapy. (B, C) Mice receiving 1×10⁶ anti-GCC CAR-T cells combined with either 1Gy x 4 fractions or 4Gy x 1 fraction showed superior tumor control (B; days 26–47) relative to the mice given the same radiation doses with 2.5 × 10⁶ cells (C; days 26–44). (D) Mice that received dual therapies (4Gy x 1 fraction, 1Gy x 4 fractions plus 1 or 2.5 × 10⁶ CAR-T cells; black, pink, green, and blue) showed extended survival relative to the other experimental treatments (p<0.001, [4Gy x 1 fraction, 1Gy x 4 fractions plus 1 or 2.5 × 10⁶s CAR-T cells vs. monotherapies]; Long-rank Mantel-Cox test). (n= 5 mice per group).