Figure 2: In vivo, Dkk-3 inhibits tumor growth in nude mice and decreases pulmonary metastasis in an orthotopic osteosarcoma mouse model. Transfected 143B cells ( ) with either PcDNA (control) or Dkk-3 were injected percutaneously into the tibia of anesthetized nude mice. (a) Tumor growth curve after implantation of tumor cells. Tumor size was measured every 3 days using a caliper and volume calculated (points reflect mean tumor volume), each group contained 10 mice; bars, SEM. (b) Harvested tumor tissue. Tumors were harvested 21 days after inoculation. (c) Lungs were harvested from mice injected with transfected control (PcDNA) and Dkk-3-143B OS cells. Arrows point to surface lung nodules. (d) Surface pulmonary nodules were counted under a dissecting microscope. Columns represent mean number of pulmonary surface nodules from 10 mice in each group; bars, SEM. (e) Immunohistochemical H&E staining (×40 magnification) of lung sections from mice inoculated with either transfected vector control or Dkk-3-143B OS cells. Arrows represent lung metastatic nodules.