Effects of avastin combined with sorafenib in a highly metastatic murine model of human hepatocellular carcinoma

Abstract

Objective To investigate the effect of combination of sorafenib and avastin,a vascular endothelial cell growth factor (VEGF) neutralizing antibody on tumor growth, lung metastasis and survival of tumor-bear nude mice in a highly metastatic xenograft murine model of human hepatocellular carcinoma (HCC). Methods Xenograft of a highly metastatic human HCC tumor (LCI-D20) was used to evaluate survival, primary tumor growth and lung metastasis after treatment with avastin alone or in combination with sorafenib. Tumor angiogenesis was identified by immunohistochemistry staining for CD31 and calculated as microvessel density (MVD). Apoptosis of tumor endothelial cells were determined by double immanofluor-esence staining for CD31 and the terminal deoxynucleotidyl-transferase mediated dUTP nick-end labeling assay (TUNEL). Results Tumor volumes were (5.70±0.17 ), (1.10±0.18), (0.60±0.12) and (2.10±0.28) mm~3 in control,serafenib,sorafenib plus avastin and avastin group. Lung metastasis was (191±23), (98±18), (31±19) and (98±20) in four groups, and median survival were 70,87,112 and 80 days,respectively. MVD were (3.77±0.44)%, (1.28±0.15)%, (0.56±0.08)%, (1.32± 0.18)% ,and indexes for apoptotic endothelial cells were (12.6±1.8)%, (32.6±8.7)%, (54.3± 11.9) %, (26.8±6.5) % respectively in four groups. Combination of avastin and serafenib significantly reduced plasma VEGF (P<0.05) ,decreased tumor volume (P<0.05) ,inhibited numbers of lung metas-tasis (P<0.01), and prolonged survival compared to mice treated with serafenib alone (P<0.05). Immu-nofluoresence staining shows reduced MVD (P<0.05) and increased apoptosis of tumor endothelial cells (P<0.05) by combination of avastin and sorafenib. Conclusion VEGF may contribute to resistance of sorafenib, avastin significantly inhibited tumor angiogenesis by inducing apoptosis of tumor endothelial cells. The study implies that it is promising to combine avastin with sorafenib for patients with advanced hepatocellular carcinoma. Key words: Sorafenib; Avastin; TUNEL