(A) Representative images of FOXO4 expression in CAFs and SL-CAFs detected by immunofluorescence staining. Scale bar: 100 μm. (B) Western blot for nuclear and total protein expression levels of FOXO4 in CAFs and SL-CAFs. (C) Cell viability assay of CAFs and SL-CAFs treated with different concentrations of FOXO4-DRI for 72 hours. The selectivity index (SI50) represents the differences of IC50 between the 2 groups by nonregression analysis. The indicated results represent the mean ± SEM of 3 independent experiments. (D) The senescence-associated gene expression changes of SL-CAFs incubated with FOXO4-DRI (50 μM) detected by Western blot. (E) H292 cell apoptosis rates after 8 Gy IR detected by flow cytometry and quantitative data of the apoptosis rates as indicated in different groups. The indicated results represent the mean ± SEM of 3 independent experiments, analyzed by 1-way ANOVA. (F) Representative images of colony formation in H292 cells cultured in different media after 0 Gy or 8 Gy IR, and statistically clonogenic survival fraction of H292 cells with different media after 8 Gy IR, determined by clone formation. The indicated results represent the mean ± SEM of 3 independent experiments, analyzed by 1-way ANOVA. (G) The cell viability of H292 determined 72 hours after 8 Gy IR and normalized to non-IR cells as indicated in different groups. The indicated results represent the mean ± SEM of 3 independent experiments. *P < 0.05; **P < 0.01; ***P < 0.001. SL-CAFs, senescence-like CAFs. DRI-CAFs, senescence-like CAFs incubated with FOXO4-DRI.