Figure 4. In vivo therapeutic activity of PEITC requires DDB2. (A and B) HCT116 cells expressing control shRNA or DDB2 shRNA were injected subcutaneously into nude mice. Mice were divided randomly in two groups for each cell line for treatment with PEITC (n = 5) or vehicle control (n = 3). Graph represents the tumor mass from control or DDB2-deficient cells line treated with PEITC or left untreated along with percent reduction in tumor mass. (C) HCT116 cells expressing control shRNA or DDB2 shRNA were injected subcutaneously into nude mice. Mice were divided randomly in two groups for each cell line for treatment with PEITC or vehicle control. Four weeks post treatment mice were sacrificed and tumor sections were fixed in 10% Formalin, processed and embedded with paraffin for sectioning. Prepared tumor section slides were then subjected to immunohistochemical analysis using DDB2 antibody. Representative images from two different tumors are shown.