The Study Of CD133+ Cells And Its Relationgship With Angiogenesis And VEGF In Colorectal Cancer

Objective:(1)To explore the expression of vascular endothelial growth factor and CD 133 and investigated their relationship with clinical significances of 94 colorectal carcinoma patients. The expression of CD 133 was correlated with MVD and VEGF.(2) Colon cancer stem cell was isolated from the colon cancer cell line SW480 and the effect of endothelial cells on VEGF expression of colon cancer stem cells was investigated.Methods:(1) The expression of CD133,VEGF and MVD(labeled by CD31) were detected by immunohistochemistry using tissue microarrays consisting of 94 specimens of colorectal carcinoma.(2) Serum-free medium under floating culture system and magnetic activated cell sorting techniques were used to enrich or separate CD 133+cells from SW480 cells. The SW480 cells and CD133+cells had been cultured in six different conditions.The expression of CD 133 and VEGF on colon cancer cells were detected by immunohistochemistry.Results:(1) Expression of CD133 was significantly associated with tumor differentiation and lymph node metastasis in colorectal carcinoma (P<0.05)(2) There were significant negative correlations between expression of CD 133,MVD and VEGF in colorectal carcinoma.(3) In colorectal carcinoma,MVD was gradually increased according to the following order:CD 133-/VEGF-,+->CD 133+/VEGF-,+→CD 133+/VEGF++,+++→CD133-/VEGF++,＋＋＋.(4) When SW480 cells were co-cultured with endothelial cells in serum-supplied medium or serum-free medium, the proportion of CD 133+cells increased significantly (P＜0.05).(5) In serum-supplied medium, CD133+cells or SW480 cells co-culture with endothelial cells showed increased expression of VEGF significantly (P<0.01)(6) The proportion of CD 133 positive cells was negatively correlated with VEGF in 6 group cells which were cultured for different time.Conclusion:(1) Endothelial cells could maintain the self-renewal and undifferentiated phenotype of CD133+cells.(2) Endothelial cells may promote angiogenesis in the way of inducing SW480 cells to express VEGF.(3) CD133+cells may promote angiogenesis in colorectal cancer though autocrine-paracrine VEGF and the increasing microvessel density stimulates the differentiation of CD133+cells.