Comparison Of Specific Silencing HIF-1α、HIF-2α And HIF-1β By SiRNA On Expression Of Vascular Endothelial Growth Factor In BGC-823 Gastric Adenocarcinoma Cell Under Hypoxia

Objective: To compare the effects of specific hypoxia inducible factor-1 alpha(HIF)-1α,HIF-2αand HIF-1β silencing by small interference RNA(siRNA)on expression of vascular endothelial growth factor(VEGF)in BGC-823 gastric cancer cell under hypoxia.Methods: Hypoxia model was established by using CoCl2 method.preparing CoCl2 of different concentrations(150 μmol/L,200 μmol/L,250 μmol/L,and 275 μmol/L).seven hypoxia groups(2 h,4 h,8 h,12 h,24 h,48 h,and 72 h).Real-time quantitative polymerase chain reaction(qRT-PCR)and Western blot were used to detect mRNA and protein expressions of HIF-1α,HIF-2α,HIF-1β and VEGF under hypoxia,and compared the expression difference of VEGF regulated by HIF-1α,HIF-2αand HIF-1β.Small RNA interference(RNAi)was used to silence BGC-823 cells and compared the effects ofHIF-1α,HIF-2α and HIF-1βon silencing VEGF.Results: Expressions of mRNA and protein of HIF-1α,HIF-2α and VEGF all increased significantly under hypoxia as compared to normoxia(P < 0.05).The expression of HIF-1α was up-regulated in hypoxia,and then decreased.The expression of HIF-2α was slowly up-regulated in hypoxia,and then was stable.The expression of HIF-1β mRNA and protein did not change in normoxia or hypoxia.siRNA transfection effectively silenced the expressions of HIF-1α and HIF-2α genes,and downregulated the expression of VEGF,and the reduction range of HIF-2α was more significant(P < 0.05).Conclusion:1.The expression of HIF-1α,HIF-2α and HIF-1β in BGC-823 gastric carcinoma cells showed different responses to hypoxia,HIF-1α and HIF-2α may play a dominant role in the process of tumor response to hypoxia in gastric cancer.2.RNA interference can inhibit the expression of three HIF genes,and to varying degrees reduce the downstream VEGF expression.Compared to HIF-1α and HIF-1β pathway,HIF-2α pathway is more meaningful and valuable in the research of targeted therapy for gastric cancer.