Figure 9. DDX6 is important for metastasis.

(A) 4T1 (WT) and DDX6 deleted 4T1 cells (DDX6KO) expressing firefly luciferase were engrafted onto the mammary fat (2.5x10⁴ cells/mouse). Deletion of DDX6 resulted in reduced primary tumor growth as assessed by bioluminescence and caliper measurements. (B) Upon necropsy, the mammary fatpad tumors were removed, fixed and stained via immunohistochemistry for expression of E-cadherin (Ecad) and the proliferive marker Ki67. Images are representative of three separate tumors for each group. (C) Pulmonary metastasis was quantified in WT and DDX6K0 tumor-bearing animals by bioluminescence readings taken at the indicated time points. (D) Representative bioluminescent images from control and DDX6KO tumor bearing mice. (E) Numbers of pulmonary metastases were confirmed upon necropsy and fixation of lung tissues. Arrows indicate pulmonary metastases. (F) Quantification of the number of pulmonary metastases in WT and DDX6KO tumor-bearing animals. (G) H&E stained histological sections from lungs of three different WT and DDX6KO tumor-bearing animals. Arrows indicate pulmonary metastases. Graphical data in panels (A), (C) and (F) are the mean ± SD of n = 4 mice per group resulting in the indicated P values.