Figure 1
Expression of Ang-2 in CRC. (A) Illustration of the steps involved in laser microdissection of cryosections of CRC patients to obtain stromal (S) and tumour (T) material for RT–PCR amplification. The top row shows capture of tumour and the bottom row capture of stroma from the same section. (B) Gel electrophoresis of end point RT–PCR amplification products of Ang-2 and β-actin on material of a whole tumour section (W) or microdissected stromal or tumour areas of sections of five different CRC patients showing Ang-2 expression in W and S, but not in T. β-Actin served as a control. The bar chart shows the relative quantitative real-time PCR of Ang-2 levels normalised to β-actin expression using the ΔCt method. Bars represent the means of five patients with standard errors showing significant Ang-2 expression (100%) in the tumour stroma, but undetectable in the tumour cells themselves (*). Some expression (<10%) is also seen when whole sections were amplified, owing to the Ang-2 expressing stromal compartment. (C) End point RT–PCR analysis of xenograft tumours of human LS174T cells in nude mice analysed by species-specific amplification for human (tumour) and murine (stromal) Ang-2. Xenograft tumours show stromal-derived murine Ang-2, but not tumour-derived human Ang-2. The GAPDH was used as a species independent control. Human umbilical vein endothelial cells (HUVEC) served as a positive control for human Ang-2.
