Involvement of the vascular endothelial growth factor receptor-1 in murine hepatocellular carcinoma development

Background/Aims The role of the vascular endothelial growth factor receptor-1 (VEGFR-1) in hepatocellular carcinoma (HCC) development has not been elucidated yet. The aim of this study was to examine the role of VEGFR-1 in VEGF-mediated HCC development and angiogenesis as compared to that of VEGFR-2. Methods We examined the effects of VEGFR-1, and VEGFR-2 neutralizing monoclonal antibodies (R-1mAb and R-2mAb, respectively) on VEGF-mediated HCC development both in an allograft and orthotopic models. Results In the allograft model, both R-1mAb and R-2mAb significantly attenuated the VEGF-mediated tumor development in a dose dependent manner with associated reduction of angiogenesis in the tumor. The inhibitory effect of R-2mAb was more potent than that of R-1mAb, and the combination treatment with both mAbs almost completely attenuated VEGF-mediated HCC development. Immunohistochemical analysis revealed that apoptosis increased markedly in the tumor. Furthermore, these inhibitory effects with both mAbs were achieved even on established tumors and orthotopic transplantation. Conclusions In addition to VEGFR-2, VEGFR-1 also lies on the signal transduction pathway by which VEGF augments HCC development and angiogenesis not only at the initial stage but also in the established tumor.