Inhibitory effect of antisense vascular endothelial growth factor RNA on the profile of hepatocellular carcinoma cell line in vitro and in vivo

Targeting angiogenesis in hepatocellular carcinoma: focus on VEGF and bevacizumab

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and one of the few malignancies with an increasing incidence in the USA. While the relationship between HCC and its inciting risk factors (e.g., hepatitis B, hepatitis C and alcohol liver disease) is well defined, driving genetic alterations are still yet to be identified. Clinically, HCC tends to be hypervascular and, for that reason, transarterial chemoembolization has proven to be effective in managing many patients with localized disease. More recently, angiogenesis has been targeted effectively with pharmacologic strategies, including monoclonal antibodies against VEGF and the VEGF receptor, as well as small-molecule kinase inhibitors of the VEGF receptor. Targeting angiogenesis with these approaches has been validated in several different solid tumors since the initial approval of bevacizumab for advanced colon cancer in 2004. In HCC, only sorafenib has been shown to extend survival in patients with advanced HCC and has opened the door for other anti-angiogenic strategies. Here, we will review the data supporting the targeting of the VEGF axis in HCC and the preclinical and early clinical development of bevacizumab.

siRNA targeting VEGF inhibits hepatocellular carcinoma growth and tumor angiogenesis in vivo

BACKGROUND/AIMS

We have investigated whether siRNA targeted against VEGF inhibits functional properties of endothelial cells in vitro and HCC tumor growth and blood vessel formation in vivo.

METHODS

The influence of siRNA-VEGF on endothelial cell proliferation, apoptosis and tube formation were analyzed in vitro. Antitumoral effects were examined in an orthotopic tumor model after ex vivo transfer or intraperitoneal treatment of siRNA, respectively. Intratumoral microvessel density was assessed by CD31 staining.

RESULTS

VEGF expression was inhibited in Hepa129 by 70% and in SVEC4-10 by 48% within two days after transfection. In vitro, endothelial cell proliferation and tube formation was reduced by 23% and 38%, respectively. Interference with VEGF signaling was demonstrated by reduced pAKT in hepatoma cells. Tumor growth was inhibited by ex vivo transfer or intraperitoneal application of siRNA-VEGF by 83% or 63% in orthotopic tumors within 14 days. VEGF protein was reduced in both models by 29% and 44%. Microvessel density dropped to 34% for tumors from ex vivo transfected cells and 39% for systemic treated tumors.

CONCLUSIONS

The results show that VEGF knockdown can be associated with reduced endothelial cell proliferation and tube formation in vitro and decreased tumor growth and microvessel density in vivo.

Focal gains of VEGFA and molecular classification of hepatocellular carcinoma

Hepatocellular carcinomas represent the third leading cause of cancer-related deaths worldwide. The vast majority of cases arise in the context of chronic liver injury due to hepatitis B virus or hepatitis C virus infection. To identify genetic mechanisms of hepatocarcinogenesis, we characterized copy number alterations and gene expression profiles from the same set of tumors associated with hepatitis C virus. Most tumors harbored 1q gain, 8q gain, or 8p loss, with occasional alterations in 13 additional chromosome arms. In addition to amplifications at 11q13 in 6 of 103 tumors, 4 tumors harbored focal gains at 6p21 incorporating vascular endothelial growth factor A (VEGFA). Fluorescence in situ hybridization on an independent validation set of 210 tumors found 6p21 high-level gains in 14 tumors, as well as 2 tumors with 6p21 amplifications. Strikingly, this locus overlapped with copy gains in 4 of 371 lung adenocarcinomas. Overexpression of VEGFA via 6p21 gain in hepatocellular carcinomas suggested a novel, non-cell-autonomous mechanism of oncogene activation. Hierarchical clustering of gene expression among 91 of these tumors identified five classes, including "CTNNB1", "proliferation", "IFN-related", a novel class defined by polysomy of chromosome 7, and an unannotated class. These class labels were further supported by molecular data; mutations in CTNNB1 were enriched in the "CTNNB1" class, whereas insulin-like growth factor I receptor and RPS6 phosphorylation were enriched in the "proliferation" class. The enrichment of signaling pathway alterations in gene expression classes provides insights on hepatocellular carcinoma pathogenesis. Furthermore, the prevalence of VEGFA high-level gains in multiple tumor types suggests indications for clinical trials of antiangiogenic therapies.

Effect of vascular endothelial growth factor 165 on apoptosis of human gastric carcinoma cells in vitro and its mechanism

AIM: To investigate the effect of vascular endothelial growth factor 165 (VEGF165) on apoptosis of human gastic adenocarcinoma cell line (BGC-823) in vitro and its underlying mechanism.

METHODS: BGC-823 cells were divided into control group, Ad-GFP group and Ad-VEGF165 group and cultured with GFP (MOI = 20) and Ad-VEGF165. Apoptotic cells were detected by FCM assay. Expression of Bcl-2 mRNA and Bcl-2 protein was determined by RT-PCR and immunocytochemistry, respectively.

RESULTS: FCM showed that the apoptosis rate of BGC-823 cells was significantly lower in the Ad-VEGF165 group than in the Ad-GFP and control groups(4.6% ± 0.31% vs 8.37% ± 1.06%, 7.73% ± 0.86%, P < 0.01). PCR and immunocytochemistry displayed that VEGF165-transfected BGC-823 increased the expression of Bcl-2 mRNA and Bcl-2 protein, which was higher in the Ad-VEGF165 group than in the control and Ad-GFP groups (Bcl-2 mRNA: 0.761 ± 0.05 vs 0.363 ± 0.12, 0.356 ± 0.08; Bcl-2 protein: 1.010 ± 0.08 vs 0.865 ± 0.07, 0.901 ± 0.05; P < 0.01).

CONCLUSION: VEGF165 can inhibit cell apoptosis induced by serum starvation by up-regulating the expression of Bcl-2.

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