Figure 7. NgBR expression in breast cancer cells contributes to the growth of breast tumor xenografts.

(A) NgBR knockdown reduces the growth rate and size of MDA-MB-231 tumor xenografts. MDA-MB-231 stable cells expressing doxycycline-inducible NgBR shRNA were subcutaneously implanted into the flank region of the nude mice. NgBR was knocked down by feeding the mice with doxycycline in drinking water when the size of the tumor xenografts reached 200 mm³. Data are represented as mean ± SEM (* P< 0.05, n=6). (B) Representative images of tumor xenografts isolated from the nude mice are shown. NgBR knockdown reduces the size of MDA-MB-231 tumor xenografts in the nude mice. (C, D) NgBR knockdown reduces the activation of H-Ras in MDA-MB-231 tumor xenografts, as indicated by isolating the activated H-Ras proteins using GST-RBD beads and detecting the proteins by Western blotting (C), and quantifying the O.D. of the proteins in the Western blots (D). Data are represented as mean ± SEM (* P< 0.05, n=4). (E, F) NgBR knockdown reduces the phosphorylation of Akt in MDA-MB-231 tumor xenografts. Immunostaining of phosphorylated Akt in MDA-MB-231 tumor xenograft (E) and quantification results (F) are shown. Data are represented as mean ± SEM (* P< 0.05, n=4).