Inhibition of human hepatocellular carcinoma tumor angiogenesis by siRNA silencing of VEGF via hepatic artery perfusion

Y. Zou, C.-G. Guo, M.-M. Zhang

Department of Radiology, Women’s Hospital, Zhejiang University, School of Medicine, Hangzhou, China. zhangminming@zju.edu.cn

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• Oncology

OBJECTIVE: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in China. Hepatic arterial chemoembolization transcatheter (TACE) is one of the main treatment methods for liver cancer. However, the long-term therapeutic effect of HCC after TACE is still unsatisfactory, postoperative recurrence and metastasis rate is still very high. Furthermore, TACE operation due to liver cancer tissue ischemia and hypoxia will lead to up-regulation of vascular endothelial growth factor (VEGF) expression. In the current study, we investigated the effects of suppressed VEGF on HCC and its molecular mechanism provided a basis for targeting angiogenesis.

MATERIALS AND METHODS: We established rabbits primary HCC model by in situ embedding the VX2 subcutaneous transplantation tumor. Conventional Seldinger femoral artery and hepatic artery catheterization method were used to select the catheter over the tumor-bearing hepatic artery. The different groups were divided into TACE operation, and the experimental group was performed with the VEGF-siRNA molecular preparation in the catheter. 64-slice spiral CT were used to perfusion imaging of liver cancer model before and after TACE operation. We further assessed the efficiency of VEGF silencing and its influence on VX2 cells. The expression of VEGF mRNA and protein were detected by RT-PCR and Western blotting, respectively. Intratumoral microvessel density (MVD), VEGF and CD34 were evaluated by immunohistochemistry. We detected the cell apoptotic by immunofluorescence and flow cytometry.

RESULTS: Our findings indicated that VEGF-siRNA-2# could effectively suppress the expression of VEGF expression, inhibited the proliferation capability and promoted apoptosis of VX2 cells in vitro. Silencing of VEGF expression also suppress HCC tumor growth and reduce HCC angiogenesis in rabbits primary HCC model in vivo. Furthermore, We found that phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT) activation were considerably reduced while inhibition VEGF expression in VX2 cells.

CONCLUSIONS: Our data demonstrated that VEGF silencing could suppress cells proliferation, promote cells apoptosis and reduce HCC angiogenesis through inactivation of VEGF/PI3K/AKT signaling pathway.

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