Effcet of Silencing HIF-1α by siRNA on Expression of Vascular Endothelial Growth Factor in Esophageal Squamous Cell Carcinoma Cell under Hypoxia

Objective To investigate the expression of HIF-1 and vascular endothelial growth factor (VEGF) in human esophageal squamous cell carcinoma cell line EC9706 under hypoxia.To observe the effect of HIF-1α on hypoxia-activatad angiogenesis regulation pathway in esophageal squamous cellcarcinoma.Methods CoCl2 was used as a chemical hypoxia-inducible reagent to mimic tumor hypoxic microenviroment.mRNA and protein levels of HIF-1α and VEGF were detected by semi-quantitative reverse transceiption-polymerase chain reaction(RT-PCR) and immunohistochemistry.With RNA interference (RNAi) originated by small interference RNA (siRNA ) to use siRNA transfected EC9706 cells.Western-blot was used to detect gene scilencing effect on HIF-1α.RT-PCR and immunohistochemistry were used to observe the change of VEGF gene expression after HIF-1α gene silence.Results Under hypoxia,mRNA level of HIF-1α was stable,while its protein level increased obviously.Both mRNA and protein levels of VEGF were up-regulated.The siRNA targeting HIF-1α gene down-regulated HIF-1 gene in EC9706 cells efficiently,and VEGF gene was down-regulated as well.Conclusion Hypoxia can increase protein level of HIF-1α in esophagus.HIF-1α up-regulates the gene expression of VEGF which promotes angiogenesis in esophagus under hypoxic microenviroment.