摘要
Abstract
Objective To investigate whether hypoxia induces differential expression of hypoxia-inducible factor- 1α ( HIF-lα ) and hypoxia- inducible factor-2α ( HIF -2α ) in SPCA - 1 cells and to explore the underlying mechanisms. Methods Lung epithelial SPCA-1 cells were cultured in vitro under hypoxia or normoxia conditions, RT-PCR and Western blot were applied to determine the activation of HIF - 2α and HIF-lα genes at different timepoints. An inhibitor of mito-chondrial reactive oxygen species was added to the medium to investigate the expression of HIF - 2α and HIF - la in the hypoxia condition as well as the underlying mechanisms. Results Under normoxia conditions in SPCA - 1, in the extract of the whole cell and the nuclear, HIF - la proteins were scarcely expressed, while HIF -2a proteins were low in the whole cell but barely expressed in the nuclear extracts. After 4 hours of hypoxia ( 0. 5% O2 ) culture, the protein levels of HIF-2α and HIF- lα obviously increased; under normal oxygen conditions, the lower of the cell density, the less HIF-2α and HIF-1α proteins produced. When the oxygen concentration dropped to below 3% , expression of HIF-2α and HIF -1α proteins were significantly increased; after 4 hours of hypoxia, HIF- lα proteins were increased. HIF- lα mRNA level dramatically reduced from 6h to 12h in hypoxia, while the HIF - 2α mRNA level significantly increased. HIF - 2α and HIF - la protein significantly decreased after SPCA - 1 cells were cultured in mitochondrial reactive oxygen species inhibitor, Rotenone, diphenyleneiodonium and myxothia-zol, for 4 hours. Conclusion Hypoxia can induce the expression of HIF - lα and HIF -2α in lung epithelial cells, mRNA and protein levels of HIF -2α and HIF - lα were different among timepoints of hypoxic adaptation. Post - translational modification plays all important roles in the induction of HIF-1α and HIF - 2α in hypoxia condition; hypoxia may play the roles of induction and regulation through the same signaling pathway on HIF-2α and HIF-1α.关键词
低氧诱导因子-1α/低氧诱导因子-2α/肺腺癌细胞/细胞低氧Key words
Hypoxia - inducible factor-lα/ Hypoxia-inducible factor-2α/ Lung epithelial cells/ Cell hypoxia分类
医药卫生
