Figure 7

Density of microvessels and hypoxia in colon tumor tissues. (A) HT29 cells expressing LEF-1-ΔL or LEF-1-FL were injected subcutaneously into nude mice. Thirty days later, the same size tumors were cut into small pieces with approximately equal sizes (about 100 mm³) at random, were sectioned in thicknesses of 10 μm and stained for CD31, VEGFR2 and HIF-1α by immunochemistry. (B) and (C) Microvessels in A labeled with anti-CD31 and anti-VEGFR2 antibodies were counted under a microscope, and microvessel densities (microvessels per field) were compared. (D) HIF-1α-positive signals in A were quantified using Image-Pro Puls 5.1 and were compared for statistical significance. (E), (F) and (G) Eighteen days after the initial inoculation of HT29 cells expressing LEF-1-ΔL or LEF-1-FL into nude mice, tumors of different groups were sectioned in thicknesses of 10 μm and stained for CD31, VEGFR2 and HIF-1α by immunochemistry. Positive signals were quantified and compared for statistical significance. Bars, mean ± SD. *P < 0.05, ** P < 0.01; n > 3.