Fig. 8: The elimination of therapy-induced senescent cancer cells through RPN1 depletion or PD-L1/PD-1-targeted therapy can enhance therapeutic efficacy by increasing CTL activity.

a–d Tumor tissues from Fig. 6 were used for analysis. (a) Representative images of SA-β-Gal staining and p21 immunostaining in tumor tissues. DAPI was used for nuclear counterstaining. Scale bar: 20 µm (top), 50 µm (bottom). b,c (b) Quantification of SA-β-Gal staining intensity and (c) p21 protein levels in tumor sections using ImageJ. Data are presented as means ± SD; n = 6 mice per group. Analysis unit: (b) 317,850 μm², (c) 77,428 μm². Two-sided Student’s t-test. d Correlation analysis between p21 and RPN1 shown in Supplementary Fig. 10. Mean ± SD of n = 6 mice per group. Spearman’s correlation test. e–j CT26 cancer cells were inoculated into BALB/c mice on day 1 (TI). Mice were irradiated with 12 Gy IR on day 13 and treated with 200 µg anti-PD-1 antibody (ICB) per mouse through intraperitoneal (IP) injection for 9 mice per group. The results of tumor growth are presented in Supplementary Fig. 12. e Representative images of SA-β-Gal staining and p21 immunostaining in tumor sections. DAPI was used for nuclear counterstaining. Scale bar: 20 µm (top), 50 µm (bottom). f, g Quantification of SA-β-Gal staining intensity (f) and p21 protein levels (g) in tumor sections from Supplementary Fig. 12 using ImageJ. Data are presented as means ± SD; (f) n = 7 mice per group, (g) n = 6 mice per group. Analysis unit: (f) 317,850 μm², (g) 77,428 μm². Two-sided Student’s t-test. h Representative images of immunostaining of CD8, Granzyme B, and caspase-3 in tumor sections with DAPI as nuclear counterstain. Scale bar: 20 µm. i, j Quantitative analysis of CD8 (i), and Granzyme B (GB) (j) using ImageJ. Data is shown as means ± SD, n = 6 mice per group. Analysis unit: 12,945 μm². Two-sided Student’s t-test. k, l CT26 cancer cells were inoculated into BALB/c mice on day 1 (TI). The mice were treated with 250 µg of anti-CD8 antibody on day 10, administered once every three days for a total of four doses. On day 11, the mice were irradiated with 12 Gy IR and subsequently treated with 200 µg of anti-PD-1 antibody (ICB) per mouse through IP injection (n = 9 mice per group). k Tumor size (in mm³) was measured at the indicated times. Two-way ANOVA with Tukey’s multiple comparison test. l Survival rates for each group until 123 days. Log-rank test. m A model showing how senescent cancer cells suppress anti-tumor immunity by modulating PD-L1 levels, potentially leading to cancer relapse. In the absence of T-cell suppressive TME with tumor volume reduction post conventional treatments, senescent cancer cells may contribute to potential cancer recurrence by acting as primary protectors of residual cancer cells by providing a PD-L1 umbrella against attack by activated T cells. Created in BioRender. Cha, J. (2023) BioRender.com/n74o053. Source data are provided as a Source Data file.