Antitumor effect utilizing antiangiogenic activity by RNAi as new gene knock-down method

众所周知，肿瘤需要持续的血管生成来支持其生长。通过产生抗血管生成因子来抑制血管生成应该是一种可行的癌症基因治疗方法。同样，抑制血管生成因子对抑制肿瘤生长也有影响。血管内皮生长因子（Vascular endothelial growth factor， VEGF）是肿瘤血管生成的关键调控因子，许多研究表明，VEGF在许多人类肿瘤中上调。我们计划使用RNA干扰（RNAi）来抑制血管VEGF受体。RNAi。转录后沉默基因表达的有力工具。RNAi技术调控肿瘤血管生成的策略以肿瘤细胞中的VEGF为靶点。我们研究了小的沉默效果。以血管内皮细胞中vegf受体（VEGFR）基因为靶点的干扰RNA （siRNA）双链抑制其血管生成活性，并在体内模型中评估其对肿瘤进展的影响。我们优化了RNAi靶序列。VEGFR-1。血管内皮细胞转染VEGFR-1 siRNA可特异性降低VEGFR-1 mRNA水平，抑制转染细胞的增殖。构建了表达短发夹rna （short hairpin rna, shRNA）作为VEGFR-1基因siRNA双链的载体。这些载体特别降低了VEGFR-1的表达。进一步优化VEGFR-2 RNAi靶序列，构建靶向VEGFR-2表达载体的shRNA。我们在体内模型中研究了这种强大的效用。实验表明，VEGFR-2-shRNA抑制肿瘤进展。因此，我们计划在体内模型中评估VEGFR-1-shRNA和两种shRNA混合的抑制效果。

It has been known that tumors require ongoing angiogenesis to support their growth. Inhibition of angiogenesis by production of antiangiogenic factors should be a viable approach for cancer gene therapy. Similarly, inhibition of angiogenic factor has an impact to suppress the tumor growth. Vascular endothelial growth factor (VEGF) is a key regulator of tumor angiogenesis and many studies have shown that VEGF is upregulated in many human tumors. We have planned to inhibit vascular VEGF receptors using RNA interference (RNAi). RNAi is. a powerful tool to silence gene expression post-transcriptionally. The strategy to regulate the tumor angiogenesis with RNAi technique targeted VEGF in tumor cell. We investigated the silencing effect of small. interfering RNA (siRNA) duplexes targeting the gene VEGF-receptor (VEGFR) in vascular endothelial cell to inhibit its activity of angiogenesis and evaluated its effect against to the tumor progression in vivo model. We optimized the RNAi target sequence.of VEGFR-1. Transfection of VEGFR-1 siRNA to vascular endothelial cell specialy reduced VEGFR-1 mRNA level and inhibit the proliferation of transfected cell. The vector that express short hairpin RNAs (shRNA) working as the siRNA duplexes to VEGFR-1 gene was constructed. These vectors specially reduced VEGFR-1 expression. Further, the RNAi target sequence to VEGFR-2 was optimized and the shRNA targeted to VEGFR-2 expression vector was constructed. We investigated this powerful utility in in vivo model. The experiment showed that VEGFR-2-shRNA inhibited tumor progression. So we plan to evaluate the inhibitory effect in in vivo model of VEGFR-1-shRNA and mix of two kind of shRNA.