Msi1 knockdown reduces breast tumor xenograft growth. A. Fluorescent imaging of GFP expression in MCF-7 and T47D breast tumor xenografts in nude mice. Tumor cells transduced with either an Msi1 shRNA or control shRNA were transplanted into opposite flanks of each animal, and after 8 weeks tumor size was visualized with a Maestro imaging instrument. B. Reduction of tumor growth by Msi1 shRNA. Bar graphs indicate the relative changes in tumor xenograft area computed by pixel imaging. Each value represents the mean ± S.E. from five animals; P < 0.02 and P < 0.05 for T47D and MCF-7 xenografts, respectively, by the two-tailed Students t test. C. Msi1 KD in MCF-7 and T47D xenograft tumors reduces Msi1 and Notch1, and increases p21CIP1 protein expression.