RP4 inhibits colorectal cancer lung metastasis in vivo. (A), Bioluminescence imaging of CT26 tumor-bearing mice injected with luciferase substrate. (B), Body weight curves (n = 6). (C), Representative H&E stain showing the metastases area of the lung from CT26 tumor model. (D), Representative images of lung metastases in a CT26 tumor model. Arrows represent pulmonary nodules. (E), The representative image of lung with metastatic nodes. Arrows represent pulmonary nodules. (F), The statistic of metastatic lung nodes (n = 6). Data are expressed as mean ± S.D. Statistical analysis was performed with t test (n = 3; **** p < 0.0001). Representative images from three independent experiments are shown.