title: Thioredoxin-1 modulates transcription of cyclooxygenase-2 via hypoxia-inducible factor-1alpha in non-small cell lung cancer.
abstract: Hypoxic induction of gene expression occurs mainly via the hypoxia-inducible factor-1 (HIF-1) transcription factor and is a critical step in tumor growth. Cyclooxygenase-2 (COX-2) is commonly overexpressed in non-small cell lung cancer (NSCLC). In this study, we sought to determine the role of HIF-1 in the induction of COX-2 expression during hypoxia. Through sequence comparison of hypoxia-responsive genes, COX-2 promoter deletion analysis, and site-directed mutagenesis, we identified a hypoxia-responsive element within the COX-2 promoter that interacts with HIF-1alpha and underlies the mechanism of hypoxic activation of COX-2 in lung cancer cells. Proteomic analysis of NSCLC identified thioredoxin-1 as a redox protein overexpressed in NSCLC correlated with poor prognosis. We also show that thioredoxin-1 stabilizes HIF-1alpha to induce hypoxia-responsive genes under normoxic conditions. Our results identify two new mechanisms for regulation of COX-2 expression in NSCLC.
authors.affiliation: Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Nashville, Tennessee 37232-6838, USA.
authors.forename: Ildiko
authors.initials: I
authors.lastname: Csiki
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Yanagisawa
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Haruki
authors.forename: Sorena
authors.initials: S
authors.lastname: Nadaf
authors.forename: Jason D
authors.initials: JD
authors.lastname: Morrow
authors.forename: David H
authors.initials: DH
authors.lastname: Johnson
authors.forename: David P
authors.initials: DP
authors.lastname: Carbone
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000096:biosynthesis* / Q000235:genetics; D004790:Enzyme Induction; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000494:pharmacology / Q000502:physiology*; D008175:Lung Neoplasms / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013879:Thioredoxins / Q000096:biosynthesis* / Q000235:genetics; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; D013879:Thioredoxins; D051546:Cyclooxygenase 2