[The inhibition of VEGF expression induced by HIF-1alpha RNA interference]

Hypoxia-inducible transcription factor-1alpha (HIF-1alpha) is a "master" gene in the cell hypoxia response network. HIF-1alpha plays the key role on VEGF-dependent angiogenesis during tumor development. In this study, the siRNA expressive vector targeting HIF-1alpha was constructed. HepG2 cells were tranfected with an HIF-1alpha siRNA vector and exposed to a normoxic or hypoxic environment. mRNA and protein levels of HIF-1alpha and VEGF were detected by RT-PCR and Western blot at different cell culture environment. The mRNA and protein expression of HIF-1alpha was inhibited by RNA interference. The obvious decreases of mRNA and protein of VEGF was induced by HIF-1alpha gene knock-down. Our study indicated that HIF-1alpha regulated the expression of VEGF and hence promoted angiogenesis in liver cancer under hypoxic environment. The expression of VEGF was downregulated via HIF-1alpha gene knock-down. These results suggest that HIF-1alpha may be used as a good target gene for anti-angiogenesis in liver tumors.