FIG. 7.
Doxycycline-regulated expression of 14-3-3σ inhibits the tumorigenesis of HER2/neu-overexpressing cells in nude mice. (A) Tumorigenicity. 3T3/HER2/tTA/14-3-3σ cells were cultured in the presence (+) or absence (−) of doxycycline (dox) for 24 h. Then 106 cells were harvested and injected subcutaneously into the flank region of female nude mice. The mice were fed water with (+) or without (−) 200 μg of doxycycline per ml. Tumor volumes were monitored for 22 days. The change in tumor volume over a 22-day period is shown in the graph. Bars represent standard deviations. (B) Gene expression. Tumor tissues from the sites of implantation were assessed for expressed Flag-14-3-3σ levels by immunoblotting with anti-Flag antibody. Representative tumors are shown.