Fig. 2. Combination of enalapril and 5-FU synergistically inhibits tumor growth, cell proliferation, and angiogenesis in vivo.

a SW620 cells were injected subcutaneously into the left flanks of nude mice. Twenty-four mice were allocated randomly to the control group (100 μl, p.o., daily), EP group (0.6 mg/kg, p.o., daily), FU group (30 mg/kg, i.p., 2 times/week), and E+F. The xenografts were resected on day 24 and the tumor volumes were measured and analyzed. Representative images of mice bearing tumor xenografts for each group were shown on the right (n = 6 per group). b Blood from mice was collected at the end of the experiment and the levels of plasma creatinine (Cr) and the levels of aspartate aminotransferase (AST) were analyzed. c Immunohistochemical analysis of CD31, VEGF-α, Ki67, and Caspase-3 in each treatment xenograft tumor tissues. d The number of positive cells was quantified in ten visual fields at ×400 magnification and the means ± SD are shown in the diagrams (n = 10 per group). e Western blot analysis of the expression of CD31, VEGF-α, Ki67, and Caspase-3 in SW620 cells treated with EP, FU, or E+F. β-Actin served as a control. The data are presented as means ± SD from three separate experiments (c–e). Statistical analysis performed using two-tailed t-test (**P < 0.01, *P < 0.05).