Figure 5.

Evaluation of the carcinomatosis progression in mice injected with MAG+ or MAG− spheroids 3 days after their formation. (A) Overview of the experiment. Magnetically molded CT26 spheroids were cultured for two days upon magnet application (MAG+ spheroids) or without magnets (MAG− spheroids). Then, for each condition, 10 spheroids per mouse were injected into the peritoneum. Mice were sacrificed 13 days later, and the Peritoneal Carcinomatosis Index (PCI) was evaluated. (B) PCI evaluation: the peritoneum is divided into 13 regions. Depending on the number and size of the tumor nodules, a score between 0 to 3 is allocated for each region. The sum of the scores provides the PCI for each mouse. (C) Typical images during PCI analysis. The white arrows indicate tumor nodules. For the two regions of the MAG+ mouse, a score of 3 was allocated. Scores of 1 and 2 were allocated for the regions n°0 and n°8 of the MAG− mouse, respectively. (D) Average PCI for mice injected with MAG+ spheroids (red bar) and MAG− spheroids (striped bar). The mice injected with the compressed spheroids (MAG+) experienced an increase in cancer progression (two different experiments, in total n = 8 and n = 10 for MAG+ and MAG−, respectively, with *** signifying p < 0.005). (E) Immunohistological staining of hepatic metastasis (indicated with white arrows) in mice injected with MAG+ spheroids. The top middle picture shows hematoxylin–eosin staining (HES, cytoplasm and nucleus labeling) of a metastasis section of approximately 800 µm in diameter (scale bar = 500 µm). The bottom middle image shows a Prussian blue staining (iron labeling, scale bar = 500 µm). Iron is clearly detected at the center of the metastasis, indicating that it originates from the injected cells. The right images present a magnification of a Ki67 staining and of a Prussian blue staining. The metastases were proliferating (Ki67-positive) and originated from the injected cells (Prussian blue positive). Scale bar = 20 µm for the right images.