ABSTRACT
The aim of this study was to evaluate the role of vascular endothelial growth factor (VECF) and its receptor flk-1 system in angiogenesis and progression of human hepatocellular carcinoma (HCC) in vivo, the flk-1 dominant-negative mutant was cloned into the retroviral expression vector pLXSN, and was then packaged by PA317 cells to produce ecotropic retroviruses expressing mutated receptor constructs. 50mm_3 of LCI D-20 intact tissue were subcutaneously or orthotopically implanted in nude mice respectively. At day 1,3,5 after implantation, growing tumor were injected with 0.1 ml retroviral supematants into the site of tumor implantation. Tumor volumes, vascular density and lung metastasis were investigated. The results showed that the transfectants by flk-1 TM formed very small tumors after 21 days, which were less than 10 folds in size compared with control. There were hardly visible vessels in flk-1 TM transfected tumor tissue, whereas rich neovascularization could be found in control. The metastatic nodules in lungs were markedly decreased by dominant-negative flk-l TM (P