Vascular endothelial growth factor antisense oligodeoxynucleotides with lipiodol in arterial embolization of liver cancer in rats.

AIM: Transcatheter arterial embolization (TAE) of the hepatic artery has been accepted as an effective treatment for unresectable hepatocellular carcinoma (HCC). However, embolized vessel recanalization and collateral circulation formation are the main factors of HCC growth and recurrence and metastasis after TAE. Vascular endothelial growth factor (VEGF) plays an important role in tumor angiogenesis. This study was to explore the inhibitory effect of VEGF antisense oligodeoxynucleotides (ODNs) on VEGF expression in cultured Walker-256 cells and to observe the anti-tumor effect of intra-arterial infusion of antisense ODNs mixed with lipiodol on rat liver cancer.
METHODS: VEGF antisense ODNs and sense ODNs were added to the media of non-serum cultured Walker-256 cells. Forty-eight hours later, VEGF concentrations of supernatants were detected by ELISA. Endothelial cell line ECV-304 cells were cultured in the supernatants. Seventy-two hours later, growth of ECV-304 cells was analyzed by MTT method. Thirty Walker-256 cell implanted rat liver tumor models were divided into 3 groups. 0.2 mL lipiodol (LP group, n=10), 3OD antisense ODNs mixed with 0.2 mL lipiodol (LP+ODNs group, n=10) and 0.2 mL normal saline (control group, n=10) were infused into the hepatic artery. Volumes of tumors were measured by MRI before and 7 d after the treatment. VEGF mRNA in cancerous and peri-cancerous tissues was detected by RT-PCR. Microvessel density (MVD) and VEGF expression were observed by immunohistochemistry.
RESULTS: Antisense ODNs inhibited Walker-256 cells' VEGF expression. The tumor growth rate was significantly lower in LP+ODNs group than that in LP and control groups (140.1+/-33.8%, 177.9+/-64.9% and 403.9+/-69.4% respectively, F=60.019, P<0.01). VEGF mRNAs in cancerous and peri-cancerous tissues were expressed highest in LP group and lowest in LP+ODNs group. The VEGF positive rates showed no significant difference among LP, control and LP+ODNs groups (90%, 70% and 50%, H=3.731, P>0.05). The MVD in LP+ODNs group (53.1+/-18.4) was significantly less than that in control group (73.2+/-20.4) and LP group (80.3+/-18.5) (F=5.44, P<0.05).
CONCLUSION: VEGF antisense ODNs can inhibit VEGF expression of Walker-256 cells. It may be an antiangiogenesis therapy agent for malignant tumors. VEGF antisense ODNs mixed with lipiodol embolizing liver cancer is better in inhibiting liver cancer growth, VEGF expression and microvessel density than lipiodol alone.