Fig. 5.

IMQ-induced ICAM-1 up-regulation synergizes with local X-RT to inhibit nonirradiated tumor growth. (A) Schematic illustration of RT combining IMQ and in vivo imaging using Dye-αICAM-1/Fab or ⁶⁴Cu-NOTA-αICAM-1/Fab. (B) Western blot analysis of ICAM-1 expression in nonirradiated tumor tissues on day 12 after treatment with RT or RT + IMQ. Quantitative results are presented as ICAM-1/β-actin ratio (n = 3 per group). (C and D) Flow cytometry analysis of ICAM-1⁺ cells and CD8⁺ T cells (C) and ICAM-1 expression on CD8⁺ cells and tumor cells (D) in nonirradiated tumor tissues on day 12 after treatment with RT or RT + IMQ (n = 6 per group). (E) Tumor growth curves of nonirradiated tumors in 4T1 tumor-bearing mice after the indicated treatments: control (PBS), IMQ alone (IMQ), RT alone (RT), RT plus anti–ICAM-1 blocking (RT + αICAM-1), RT plus IMQ plus anti–ICAM-1 blocking (RT + IMQ + αICAM-1), and RT plus IMQ (RT + IMQ) (n = 6 to 7 per group). (F) Representative NIRF images and quantitative analysis of tumor uptake of Dye-αICAM-1/Fab at 6 hpi in 4T1 tumor-bearing mice after treatment with RT or RT + IMQ (n = 4 to 5 per group). (G) Representative small animal PET images and quantitative analysis of tumor uptake of ⁶⁴Cu-NOTA-αICAM-1/Fab at 6 hpi in 4T1 tumor-bearing mice after treatment with RT or RT + IMQ (n = 5 per group). Nonirradiated tumors are indicated by red circles. Numerical data are presented as mean ± SD. (H) Correlation analysis of relative tumor volume on day 20 (V₂₀/V₀) and tumor uptake of ⁶⁴Cu-NOTA-αICAM-1/Fab on day 12. *P < 0.05; **P < 0.01; ***P < 0.001 by unpaired Student t test (B–D, F, and G), two-way ANOVA (E), or Pearson correlation analysis (H).