[Coexpression of vascular endothelial growth factor and its receptors in human tumor cell lines]

Vascular endothelial growth factor (VEGF) play an important role in tumor angiogenesis through a paracrine mechanism, but the importance of its autocrine has not been fully elucidated. This study was designed to explore the gene coexpression pattern of VEGF and its receptors (Flt-1 and KDR) in variety of human malignant cell lines.

After isolation of RNA from thirty tumor cell lines and four endothelial cells, gene expressions of VEGF and its receptors were measured by semi-quantitative reverse transcriptase polymerase chain reaction using the transcriptional level of the house-keeping gene for internal calibration.

VEGF transcript was detected in the majority of tumor cell lines (29/30) and in all endothelial cell lines at moderate or high level, while the expression of VEGF was low in human umbilical vein endothelial cell (HUVEC). Moreover, Flt-1 gene expression was found in 50% of hematopoietic malignancies (6/12), 28% of solid tumors (5/18), and endothelial cells (EA. hy926 and HUVEC). In contrast, the expression of KDR gene was found in 2 (16.7%) hematopoietic cell lines and 6 (33.3%) solid tumor lines. In endothelial cells, KDR gene expression was detectable in HMEC-1 and HUVEC only. However, ECV304 cells express neither Flt-1 nor KDR gene.

Overexpression of VEGF gene in all tumor cell lines provides a potential biological marker for malignancies and the coexpression of VEGF with its receptors suggesting an autocrine pathway exists in tumor cells.