| Previous studies have shown the differences of tumor microvessels in density, morphology, structure and three-dimensional distributions within a tumor due to various angiogenic factors produced by tumor cells. With the progression of tumor and increase in tumor cell heterogeneity, the aforementioned differences will exhibit diversity and variability, a pathological event defined as tumor microvascular architecture phenotype heterogeneity (T-MAPH). Angiogenesis factors and other mechanism may be involved in the process of T-MAPH.To investigate the roles of different spatial distribution and concentrations of VEGF in the pathogenesis of T-MAPH, HUVECs were inoculated on Matrigel by using a three-dimensional culture system in the prevent study. HUVECs have proliferation and differentiation potentials and the properties of new vessel endothelial cells; moreover, there are ample sources of HUVECs and they are easy to culture in vitro. Matrigel, an extracellular matrix compound extracted from mouse tumor, can promote endothelium growth and the tubule-like structure (TLS) formed in the gel can be similar to that in vivo. Endothelial cells were cultured in Matrigel to promote them to manifest the properties of endothelial cells of various tumors. Then the cells were stimulated by various concentrations of VEGF, and TLS was observed at various time points. The expression of ephrinB2, EphB4 and KDR at various time points by HUVECs treated with various concentrations of VEGF was determined by immunochemistry and laser confocal microscopy. In addition, the effect of VEGF on the expression of ephrinB2, EphB4 and KDR were investigated. The main results and conclusions are as follows:1. When VEGF concentrations ranged from 2.5ng/ml to 50ng/ml, the number of TLS formed by HUVECs was increased in a dose- and time-dependent manner. This effect was the most apparent at VEGF concentrations ranging from 10ng/ml to 50ng/ml. The TLS...
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