Figure 6.

U2 Inhibits DNA Damage Repair after Radiation

(A) U87-EGFRvIII cells were incubated with U2-Scr1 or U2 (200 nmol/L). After 24 hr, the monolayer cells were exposed to a single dose of irradiation with 2 Gy and harvested 3 hr post irradiation for the comet assay. (B) The cells were treated as in (A). The tail DNA content, tail moment, and olive tail moment were calculated by software to assess the severity of DNA damage under each condition after irradiation therapy. ***p < 0.001. (C) Picture of U87EGFRvIII cells treated with U2 or U2-Scr1 (200 nmol/L), with exposure to a single dose of 2 Gy. The cells were then submitted to a clonogenic assay after radiotherapy. ***p < 0.001. (D) U87-EGFRvIII cells were starved in 2% FBS-containing medium for 6 hr and then incubated with 200 nM U2-Scr1 or U2 for 24 hr. After exposure to irradiation (2 Gy), cells were harvested for 6 hr post irradiation and the lysates were immunoblotted for phosphorylated and total markers related to DNA damage repair, as indicated. *p < 0.05. (E) The cells were treated as in (D), and the lysates were collected and immunoblotted with anti-pEGFRvIIIand anti-EGFRvIII antibodies. *p < 0.05.