ABSTRACT:ObjectiveTo observe the expression of hypoxiainducible factor2alpha (HIF2α) in human prostate cancer PC3 cell under hypoxia, and investigate the effects of silencing HIF2α gene by siRNA on PC3 cell apoptosis and proliferation under hypoxia.MethodsTumor hypoxia was induced by CoCl2 chemical hypoxia method.RTPCR and Westernblot was performed to detect the expression of HIF2α mRNA and protein in human prostate cancer PC3 cells, and the relations of the quantityefficiency and the timeefficiency were analyzed.siRNA was chemically synthesized and transfected into PC3 cells.The expressions of HIF2α in hypoxia microenvironment were respectively detected by RTPCR and Westernblot.The effects of apoptosis and proliferation were detected by FCM and MTT assay.Results(1)Hypoxia improved HIF2α expression in PC3 cells in a timedependent manner.Compared with the normal oxygen group, the HIF2α mRNA and protein expression level was significantly higher in 12 h, 24 h, and 48 h group(P<0.05).The best model of hypoxia was 48 h group induced by 100 μmol/L CoCl2.(2)The levels of mRNA and protein of HIF2α were suppressed significantly after being treated with HIF2α siRNA in PC3 cells(P<0.05), but there was no significant difference in cell proliferation and apoptosis between CoCl2 negative control group and CoCl2 group(P>0.05).The proliferation potential and apoptosis in PC3 cells were changed significantly after transfecting HIF2α siRNA(P>0.05), but there was no significant difference among normal oxygen group, CoCl2 groups, and CoCl2 negative control group(P>0.05).ConclusionHIF2α is overexpressed in human prostate cancer cell PC3 after CoCl2 treatment.HIF2α siRNA effectively reduces the HIF2α mRNA expressions in PC3 cells.Tansfecting HIF2α siRNA inhibits PC3 cells proliferation and increases PC3 cells apoptosis.Blocking HIF2α signal pathway can be a potential strategy in the treatment of androgen independent prostate cancer.