Fig. 1.

SOCS1 promotes radiation-induced apoptosis of HCT116 cells involving increased DNA damage and p53 activation. HCT116/p53wt cells stably transfected with HA and HA-SOCS1 constructs were exposed to indicated doses of γ-IR. Cells were harvested at 24 h and apoptotic cells were measured by Annexin-V staining (A). Cells were treated with γ-IR at 5 Gy (B-D) and analyzed for DNA damage by performing Terminal deoxynucleotide transferase dUTP nick end label-ling (TUNEL) assays (B). Apoptosis was determined at 48 h upon receiving 5 Gy (C). Western blot was performed for p-p53, p53, and SOCS1 with densitometric analysis of protein levels (D).