Fig. 4

Inhibition of murine colorectal cancer growth in vivo by Salinomycin. Colorectal cancer growth in BALB/c-mice was induced through injection of CT26 cells. Cells were either injected subcutaneously into the flank of the animals, into the wall of the cecum to induce orthotopic tumor growth or into the portal vein to induce metastatic spread. After 1 week, treatment with either 5-FU, Salinomycin or 5-FU and Salinomycin was performed (a). b After 2 weeks of treatment, Salinomycin significantly inhibited colorectal cancer growth in the subcutaneous tumor model compared to control. Scale bars, 15 mm. c Orthotopic colorectal cancer growth was also statistically significant abolished after treatment with Salinomycin for 2 weeks. Results are shown as mean tumor volume ± SD, * p < 0.05, ** p < 0.001 compared with control. d-f The distribution of metastatic colorectal cancer spread in the liver of mice (indicated as #) was also markedly reduced after treatment with Salinomycin. Results are shown as representative images of CRC liver spread, H&E stained sections or mean of the percentage of metastatic area ± SD of 9 individual experiments, * p < 0.05. g TNUEL assay was performed to investigate the amount of apoptotic cells within the explanted murine tumors. After removal of paraffin, slides were stained with TUNEL reagents according to the manufacturers instructions. The displayed result is a representative image of an orthotopic colorectal cancer specimen