Fig. 9
Involvement of DNA repair in CAF radioresistance. A Effect of DNA repair inhibitors on basal levels of DNA damage: Micronucleus formation in (a) AG1522 or (b) MRC5 cells cocultured for 120 h with themselves or MDA-MB-231 cells, followed by the addition of DNA SSB (PJ 34) or DSB (NU 7441) repair inhibitors. The inhibitors did not significantly increase basal micronuclei frequency. There was a significant increase in micronuclei frequency in AG1522 CAFs following coculture with MDA-MB-231 (p < 0.05). The results are representative of three separate experiments. B Radioresistance of CAFs and its mediation by DNA repair: Micronucleus formation in (a) AG1522 or (b) MRC5 CAFs cocultured for 120 h with MDA-MB-231, followed by the addition of DNA SSB (PJ 34) or DSB (NU 7441) repair inhibitors and exposure while in coculture to 0.5 Gy or 1 Gy of 137Cs γ-rays, respectively. Values in fold-change are normalized to respective sham-irradiated control. The addition of either inhibitor attenuated the protection against the radiation insult in both the AG1522 and MRC5 CAFs. The results are representative of three separate experiments