Figure 3.
The metastatic properties of SW620 cells with different levels of βig-h3 expression. (A) The expression level of βig-h3 in SW620-βig-h3n, SW620-VEC, and SW620-βig-h3-shRNA1 cells. SW620-βig-h3-shRNA1 cells were infected with recombinant retroviruses containing shRNA-resistant βig-h3 full-length cDNA (βig-h3n) tagged with the Flag-epitope (SW620-βig-h3n). An equal amount of concentrated supernatant from each cell type as indicated was examined for the presence of βig-h3 by Western blot using an anti-βig-h3 antibody. The whole-cell lysate from each sample of cells from which the supernatant was collected for the determination of βig-h3 expression was blotted with anti-tubulin antibody for loading control. (B) Mice were injected intravenously with SW620-βig-h3n or SW620-VEC cells expressing a luciferase gene and subjected to in vivo imaging at indicated time points, with relative light unit counts indicated in color. (C) In vivo bioluminescent imaging of a mouse 4 wk after being inoculated with SW620-βig-h3n cells. (D,E) At necropsy, the skull (without brain tissue) of the same mouse shown in C was removed and imaged ex vivo for photographic (D) and bioluminescence (E) imaging. (F,G) SW620- and SW480-derived cells as indicated were inoculated intracardially into 5-wk-old nude mice. SW620 or SW480 cells were labeled with luciferase, and 1 × 106 cells were injected into the left cardiac ventricle of five mice for each group. At the indicated days after inoculation, bioluminescence images were acquired. Tumor metastasis was measured by bioluminescence and quantified. Results are the mean ± SD of five animals from each group. (*) P < 0.05. Two independent experiments were performed. (H) Representative in vivo bioluminescent images of animals after intracardiac inoculation. Representative mice from SW620-βig-h3n, SW620-VEC, and SW620-βig-h3-shRNA1 groups are shown in the prone position, with relative light unit counts indicated in color.