Fig. 4. Decreased incidence of liver metastasis after pTrap LCP treatment.

(A) Mice were inoculated with 2 × 10⁶ CT-26(FL3) RFP/Luc cells into the cecum wall. Treatment schedule is shown above. Treatment, 10 mg (0.5 mg/kg) of pDNA, was administered intravenously through the tail vein on days 10, 12, and 14. Groups included PBS (untreated; n = 7) and pGFP LCP (10 mg every other day × 3; n = 6), as well as pTrap LCP (10 mg every other day × 3; n = 7). Progression of overall tumor mass was followed by administration of 200 of ml luciferin (10 mg/ml) intraperitoneally. Luciferase bioluminescence imaging was recorded 10 min after administration of luciferin. Whole mouse and liver tumor burden were recorded. All data are means ± SD and reported as bioluminescent intensity. The P values of individual groups compared to corresponding untreated control are displayed in graph. (B) Total organ tumor burden of untreated (n = 3) and therapeutic pTrap LCP (n = 4) groups. Quantification of tumor burden in organs was performed with IVIS/Kodak software. All data are means ± SD and reported as bioluminescent intensity. The P values of individual groups compared to corresponding untreated control are displayed in graph. (C) Paraffin-embedded liver sections were stained with trichrome. Large tumor burden (indicated by black arrows) and cirrhosis/fibrosis (blue stain, collagen) are clearly seen in the PBS (untreated) and pGFP LCP treatment groups. The pTrap LCP– treated livers have normal healthy liver morphology and no detectable metastatic burden. Scale bars, 250 μm. Collagen quantification in liver section was recorded. All data are means ± SD. The P values of individual groups compared to corresponding untreated control are displayed in graph.