Molecularly targeted therapy of human hepatocellular carcinoma xenografts with radio-iodinated anti-VEGFR2 murine-human chimeric fab

Abstract

Vascular endothelial growth factor receptor 2 (VEGFR2) is traditionally regarded as an important therapeutic target in a wide variety of malignancies, such as hepatocellular carcinoma (HCC). We previously generated a murine-human anti-VEGFR2 chimeric Fab (cFab), named FA8H1, which has the potential to treat VEGFR2-overexpressing solid tumors. Here, we investigated whether FA8H1 can be used as a carrier in molecularly targeted therapy in HCC xenograft models. FA8H1 was labeled with 131 I, and two HCC xenograft models were generated using BEL-7402 (high VEGFR2-expressing) and SMMC-7721 (low VEGFR2-expressing) cells, which were selected from five HCC cell lines. The biodistribution of 131 I-FA8H1 was determined in both models by Single-Photon Emission Computed Tomography and therapeutic effects were monitored in nude mice bearing BEL-7402 xenografts. Finally, we determined the involvement of necrosis and apoptotic pathways in treated mice using immunohistochemistry. 131 I-FA8H1 levels were dramatically reduced in blood and other viscera. The therapeutic effect of 131 I-labeled FA8H1 in the BEL-7402 model was significantly better than that by 131 I and FA8H1 alone. We observed extensivenecrosis in the treated tumors, and both FasL and caspase 3 were up-regulated. Thus, 131 I-anti-VEGFR2 cFab has the potential to be used for molecularly targeted treatment of HCC overexpressing VEGFR2.