Fig. 5.

Altered DNA damage repair with IR+HT. (Aa, Ad and B; Ca, Cd and D) Thirty minutes after IR (red columns) and IR+HT (yellow columns) treatment, all cells have small 53BP1 foci with a nondistinct staining pattern (checkered columns). (Ab and B; Cb and D) A significant number of cells have repaired foci or have distinct foci remaining 6 hours after IR (red columns). (Ac and B; Cc and D) A significant number of cells have repaired DSBs and lost most foci by 48 hours (B) or 72 hours (D) after IR (red columns). (Ae and B; Ce and D) With IR+HT (yellow columns), a significant number of cells have not repaired foci or have formed distinct foci at 6 hours after IR+HT. (Af and B; Cf and D) No significant change from the 6-hour time point was observed 48 hours (B) or 72 hours (D) after IR with HT. Cells were treated with IR or IR+HT in vitro after sorting populations (a, b, d, and e), and with IR or IR+HT in vivo (c and f). Scale bars, 20 μm (A), 15 μm (C). (B and D) IR (red columns), damage is significantly reduced at 6 hours after IR treatment and repair continues at 48 and 72 hours (D) hours. IR+HT (yellow columns), a significant percentage of cells with non-distinct foci (checkered columns) at 6 hours with an inability to form or repair foci at 48 hours (B) and 72 hours (D) (*P < 0.01).