10666126

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During adaptation to hypoxic and hyperoxic conditions, the genes involved in glucose metabolism are upregulated. To probe involvement of the transcription factor hypoxia-induced factor-1 (HIF-1) in hexokinase (HK) II expression in human pulmonary cells, A549 cells and small-airway epithelial cells (SAECs) were exposed to stimuli such as hypoxia, deferoxamine (DFO), and metal ions. The largest increase in HK-II (20-fold for mRNA and 2.5-fold for enzymatic activity) was observed in A549 cells when exposed to DFO. All stimuli selectively increased the 5.5-kb rather than 4-kb transcript in A549 cells. Cycloheximide and actinomycin D inhibited these responses. In addition, cells were transfected with luciferase reporter constructs driven by the full-length HK-II 5'-regulatory region (4.0 kb) or various deletions of that region. A549 cells transfected with the 4.0-kb construct and exposed to hypoxia or DFO increased their luciferase activity 7- and 10-fold, respectively, indicating that HK-II induction is, at least in part, due to increased gene transcription. Sixty percent of the inducible activity of the 4.0-kb construct was shown to reside within the proximal 0.5 kb. Additionally, cotransfection with a stable HIF-1 mutant and the 4.0-kb promoter construct resulted in increased luciferase activity under normoxic conditions. These results strongly suggest that HK-II is selectively regulated in pulmonary cells by a HIF-1-dependent mechanism.

eng

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MEDLINE

1040-0605

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L407-16

pubmed-meshheading:10666126-Anoxia, pubmed-meshheading:10666126-Cell Line, pubmed-meshheading:10666126-DNA-Binding Proteins, pubmed-meshheading:10666126-Deferoxamine, pubmed-meshheading:10666126-Gene Expression, pubmed-meshheading:10666126-Hexokinase, pubmed-meshheading:10666126-Humans, pubmed-meshheading:10666126-Hypoxia-Inducible Factor 1, pubmed-meshheading:10666126-Hypoxia-Inducible Factor 1, alpha Subunit, pubmed-meshheading:10666126-Luciferases, pubmed-meshheading:10666126-Lung, pubmed-meshheading:10666126-Nuclear Proteins, pubmed-meshheading:10666126-Nucleic Acid Synthesis Inhibitors, pubmed-meshheading:10666126-Promoter Regions, Genetic, pubmed-meshheading:10666126-Protein Synthesis Inhibitors, pubmed-meshheading:10666126-RNA, Messenger, pubmed-meshheading:10666126-Respiratory System, pubmed-meshheading:10666126-Transcription Factors, pubmed-meshheading:10666126-Transfection

Hypoxia induces hexokinase II gene expression in human lung cell line A549.

Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't