Figure 2.

Smad4 inactivation in CT26 cells increases tumorigenicity, and promotes spontaneous liver metastasis. (A) An orthotopic CRC animal model was established by injecting CT26 cells, one vector control, and three Smad4 knockdown clones into the caecum of mice (n=5). Representative pictures of the tumour mass in caecum, liver, and spleen are shown. The number of mice with liver or splenic metastasis was determined. ^#Total number of visible liver metastases. (B) The primary tumours and livers described above were weighed. Liver weight was compared with the total body weight to present liver metastasis. Each bar shows the mean±s.d. values from five mice in each group. *P<0.01, ***P<0.0001. (C) Lysate from primary tumours in caecum was used for western blotting analyses. (D) Tissue sections from caecum, liver, and spleen were subjected to immunostaining for H&E and Ki67. Black line and arrows show the submucosa, while white line and arrows show the subserosa of the caecum. The white arrow shows the structure of the subserosa that was disrupted by tumour cells. The red arrow in the liver section shows that the tumour cells metastasise to liver parenchyma through the portal vein. Magnification: × 50 and × 400.