Figure 4.

VEGF₁₂₁b reduces tumour growth in nude mice bearing colon carcinoma tumours by reducing tumour vessel ingrowth. (A) LS174t human colon carcinoma cells were transfected with pcDNA₃-VEGF₁₂₁b or empty pcDNA3 plasmid and injected subcutaneously into nude mice and tumour growth was monitored over time. Over-expression of VEGF₁₂₁b resulted in a reduced tumour growth and contained less blood compared with control cells (inserted images). Scale bar=10 mm. (B) Immunohistochemistry staining of tumour sections for VEGFR-2 visualise microvessels (inserted images). Quantification of microvascular density showed significantly fewer blood vessels per unit area than control tumours. Each point represents the mean of 10 random analysed fields and six tumours per treatment were examined (^*P<0.05 unpaired t-test). (C) Cleaved caspase 3 staining of tumour sections (inserted images) showed no significant difference in apoptosis. (D, E) VEGF₁₂₁b has no effect on LS174t colon carcinoma growth in vitro. Over-expression of VEGF₁₂₁b in LS174t colon carcinoma cells had no effect on cell proliferation analysed by FACS (D). Addition of 1 nM VEGF₁₂₁b had no effect of cell number analysed by direct counting of cells over 48 h (E).