Inhibitory effect of antisense vascular endothelial growth factor 165 eukaryotic expression vector on proliferation of hepatocellular carcinoma cells

Efficient suppression of tissue factor synthesis using antisense oligonucleotides selected by an enhanced strategy for evaluation of structural characteristics

Selection of optimal antisense constructs is still a problem. Among a huge number of antisense oligonucleotides (AS-ONs) only a small piece show inhibitory efficacy. We want to develop an enhanced strategy for specific selection of effective AS-ONs based on prediction of secondary structure of the target messenger RNA (mRNA) and analysis of thermodynamic properties of the mRNA/AS-ON hybrid. Numerous AS-ONs targeted on human tissue factor (TF) mRNA were investigated to evaluate the relevance of different thermodynamic and structural properties on inhibitory efficacy. Cell viability, TF protein and TF mRNA were determined after transfection of bladder cancer cell line J82. Inhibitory efficacy was related to GC content, target region within the TF mRNA and stability of the mRNA/AS-ON hybrid or affinity of the AS-ON to the target mRNA. We found effective AS-ONs targeted on translated region or 3'-untranslated region of TF RNA. We also detected a great correlation between inhibitory efficacy and GC content as well as stability of the mRNA/AS-ON hybrid.

Gene therapy of liver cancer

The application of gene transfer technologies to the treatment of cancer has led to the development of new experimental approaches like gene directed enzyme/pro-drug therapy (GDEPT), inhibition of oncogenes and restoration of tumor-suppressor genes. In addition, gene therapy has a big impact on other fields like cancer immunotherapy, anti-angiogenic therapy and virotherapy. These strategies are being evaluated for the treatment of primary and metastatic liver cancer and some of them have reached clinical phases. We present a review on the basis and the actual status of gene therapy approaches applied to liver cancer.

Vascular endothelial growth factor antisense pretreatment of bladder cancer cells significantly enhances the cytotoxicity of mitomycin C, gemcitabine and Cisplatin

PURPOSE

Due to unsatisfactory success in the treatment of local and systemic bladder cancer and the low response rates to commonly used chemotherapy (CT) alternative and additive approaches must be found. The function of vascular endothelial growth factor (VEGF) in neo-angiogenesis and, therefore, in solid tumors makes it a promising target for a specific antitumor therapy. We investigated the possibility of sensitizing transitional bladder cancer cell lines to CT by pretreatment with VEGF antisense (AS) oligodeoxynucleotides (AS-ODNs).

MATERIALS AND METHODS

The human bladder cancer cell lines EJ28 and 5637 were transiently transfected with 3 antiVEGF AS-ODNs, followed by incubation with 3 doses of mitomycin C, gemcitabine or cisplatin CT. WST-1 (a sodium salt of 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate) assay (Roche, Mannheim, Germany) was performed to assess effects on cell viability. Apoptosis was examined by Annexin V staining. In all experiments a nonsense ODN served as a control.

RESULTS

Each cell line responded in a dose dependent manner to all CTs. Combined treatment with VEGF AS-ODNs and CT resulted in decreased viability compared with isolated CT. VEGF857 plus CT significantly decreased the viability of the 2 cell lines compared with nonsense ODN plus CT for all 3 CT agents (p <0.007). This detected chemosensitization was based on an AS mediated increase in apoptosis.

CONCLUSIONS

One of the 3 AS-ODNs tested (VEGF857) significantly sensitizes human transitional cell carcinoma cells to CT. We suggest VEGF as an additional putative target to enhance the therapeutic benefit of, for example mitomycin C and gemcitabine instillation treatment schedules.

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Inhibitory effect of antisense oligonucleotide on the expression of survivin gene and proliferation of human hepatocellular carcinoma cell line SMMC-7721

AIM: To investigate the inhibitory effect of survivin antisense oligonucleotide (ASODN) on the expression of survivin gene and proliferation of human hepatocellular carcinoma cell line SMMC-7721.

METHODS: The 20mer antisense oligonucleotide (ASODN) targeted to the promotor region of survivin mRNA was designed and synthesized. The expression of survivin gene in hepatocellular carcinoma cell line SMMC-7721 was blocked by means of ASODN transfection mediated by DOTAP liposomal reagent. The changes of survivin protein and mRNA expression after transfection were assessd by Western blot and in situ hybridization, respectively. The apoptotic rate was detected by flow cytometer. The changes of cell adherent rate, cell growth activity, and the inhibitory rate of cell growth were also studied.

RESULTS: The expression of survivin protein and mRNA was decreased markedly after survivin ASODN transfection (69.59 vs 10.71, and 75.61 vs 22.94, P < 0.01). Meanwhile, the cell adherent rate also decreased markedly (90.68% vs 33.16%, P < 0.01) while the apoptotic rate increased markedly (0.7% vs 31.35%, P < 0.01). The inhibitory effect on the cell growth could maintain about a week after transfection, and the highest inhibitory rate could be 71.8% three d after transfection.

CONCLUSION: Transfection of ASODN targeted to the promotor region of survivin mRNA by DOTAP liposomal transfection reagent can down-regulate the expression of survivin protein and mRNA significantly in 7721 cell line and inhibit the proliferation of cancer cells. survivin may be an important target in the therapy of hepatocellular carcinoma.