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. 2019 Jan 14;129(2):786–801. doi: 10.1172/JCI97631

Figure 6. ROS mediate SUMO dysfunction and synthetic tumor lethality via the reproductive death pathway.

Figure 6

(A–E) Experiments were performed using MCA/129 fibrosarcoma. Data were collated from 2–4 independent experiments using 2–4 mice per experiment. (A) Representative images (left; scale bar: 20 μm) and quantitation (right; data represent mean ± 95% CI) of dihydroethidium staining (DHE, red) and DAPI counterstaining (blue) of tumors in asmase+/+ mice before and 1 hour after SDRT, with or without BQ-123 (designated B, 30 minutes before SDRT) or tempol (designated T, 30 minutes after SDRT). *P < 0.05, Bonferroni correction (threshold: α = 0.05/3 = 0.017). (B) Prdx6 overexpression or tempol abrogates the SSR induced by SDRT. Representative WBs of whole-cell lysates from tumors in asmase+/+ (WT) mice. (C) Tempol abrogates chromatin-associated SUMO3 depletion. Representative WB of chromatin-enriched extract from tumors in asmase+/+ mice. (D and E) Prdx6 overexpression or tempol abrogates delayed γH2AX focus resolution (D) and restores BRCA1 and RAD51 loading into repair foci (E) in SDRT-I/R–competent (WT or KO+C) tumors. Data represent median ± IQR. **P < 0.01, ****P < 0.0001 for all focus types vs. WT, Bonferroni correction (threshold: α = 0.05/8 = 0.00625). (F) Left: Representative images of micronuclei (MN; arrows) in H&E-stained tumor sections. Scale bar: 5 μm. Right: MN quantitation; data represent mean ± 95% CI from 3 independent experiments using 3 mice per group, 2,000 cells per tumor. *P < 0.05, **P < 0.01 for 15 Gy and 15 Gy + C vs. unirradiated WT, Bonferroni correction (threshold: α = 0.05/4 = 0.0125). (G) Ablation of MCA/129 fibrosarcomas in sv129/BL6 mice is aborted by pre-SDRT treatment with BQ-123 or post-SDRT treatment with tempol. Each line represents an individual tumor volume. Arrows indicate day of SDRT. Tumors undetectable at 120 days are considered cured.