Significance of vascular endothelial growth factor/vascular permeability factor for solid tumor growth, and its inhibition by the antibody.

Angiogenesis is essential for successful tumor growth in vivo. There is a hypothesis that tumors secrete a putative tumor angiogenic factor (TAF) to facilitate blood vessel formations. Although several endothelial growth factors have been reported, it remains unclear whether these factors function as TAF in vivo. Vascular endothelial growth factor (VEGF)/vascular permeability factor (VPF) is a vascular endothelial mitogen that can increase blood vessel permeability. We have established a cell line (HeLa/v5), which secretes VEGF/VPF, by transfection of human VEGF/VPF cDNA. HeLa/v5 showed higher angiogenic activity, taken/planted ratio and tumor growth rate than the control transformant (HeLa/c), when they were implanted to nude mice. Administration of a polyclonal antibody, which neutralizes the mitogenic activity of VEGF/VPF in vitro, to the tumor implanted nude mice suppressed the in vivo growth of HeLa/v5. Furthermore, all 8 tumor cell lines we tested secrete VEGF/VPF into culture media. Our findings indicate that VEGF/VPF is a tumor angiogenic factor.