Fig. 1: PROCR dampens the efficacy of radiotherapy via an immune-dependent way.

A Left: representative images of dual IHC staining of paraffin-embedded human NPC tissue sections using PROCR (brown) and CD31(red). Scale bar, 50 μm. Right: separation of tumour and stroma areas using the HALO software. B Correlation analysis of PROCR expression and locoregional recurrence status after radical chemoradiotherapy. The P value was determined by two-tailed χ² test. C PROCR knockout (sgPROCR) or parental (sgGFP) MC38 cells were inoculated into C57BL/6 mice (1 × 10⁶ MC38 cells/mouse) to construct xenograft growth models. Tumour volume for each group were shown (6 mice per group). D–F MC38 cells expressing inducible shScramble (Tet-shSCR) or inducible shPROCR (Tet-shPROCR) were inoculated subcutaneously into C57BL/6 mice (1 × 10⁶ MC38 cells/mouse, 6 mice per group). 15 days after inoculation, doxycycline (0.2 mg/ml + 1% sucrose) was added to drinking water. Mice in the IR-treated groups were subjected to focal radiation with a single fraction of 4 Gy on day 15 after tumour cell inoculation. Tumour growth curves were monitored, and tumour volumes and weights were compared at the indicated time points. G–I Tet-shSCR or Tet-shPROCR MC38 cells were inoculated (6 mice per group). Overall T cells were depleted with anti-CD3ε mAb at indicated time points. Doxycycline was added to drinking water as indicated. Mice in the IR-treated groups were subjected to 4 Gy radiation. Tumour growth curves were monitored, and tumour volumes and weights were compared at the indicated time points. J, K sgPROCR or sgGFP MC38 cells were inoculated into Balb/c-Nu/Nu mice (5 mice per group). Mice in the IR-treated groups were subjected to 4 Gy radiation. Tumour growth curves were monitored and compared at the indicated time points. L, M MC38 cells were inoculated into C57BL/6 mice (6 mice per group). 15 days after inoculation, mice were treated with irradiation plus IgG or anti-PROCR monoclonal antibody. Tumour growth curves were monitored and compared at the indicated time points. Data are shown as mean ± SEM. P values were calculated using one-way ANOVA (F, I) or two-way ANOVA (C, E, H, K, M). Source data are provided as a Source Data file.