Hypoxia-inducible expression of tumor-associated carbonic anhydrases.
The transcriptional complex hypoxia-inducible factor-1 (HIF-1) has emerged as an important mediator of gene expression patterns in tumors, although the range of responding genes is still incompletely defined. Here we show that the tumor-associated carbonic anhydrases (CAs) are tightly regulated by this system. Both CA9 and CA12 were strongly induced by hypoxia in a range of tumor cell lines. In renal carcinoma cells that are defective for the von Hippel-Lindau (VHL) tumor suppressor, up-regulation of these CAs is associated with loss of regulation by hypoxia, consistent with the critical function of pVHL in the regulation of HIF-1. Further studies of CA9 defined a HIF-1-dependent hypoxia response element in the minimal promoter and demonstrated that tight regulation by the HIF/pVHL system was reflected in the pattern of CA IX expression within tumors. Generalized up-regulation of CA IX in VHL-associated renal cell carcinoma contrasted with focal perinecrotic expression in a variety of non-VHL-associated tumors. In comparison with vascular endothelial growth factor mRNA, expression of CA IX demonstrated a similar, although more tightly circumscribed, pattern of expression around regions of necrosis and showed substantial although incomplete overlap with activation of the hypoxia marker pimonidazole. These studies define a new class of HIF-1-responsive gene, the activation of which has implications for the understanding of hypoxic tumor metabolism and which may provide endogenous markers for tumor hypoxia.
Wykoff
C C
CC
Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, United Kingdom.
Beasley
N J
NJ
Watson
P H
PH
Turner
K J
KJ
Pastorek
J
J
Sibtain
A
A
Wilson
G D
GD
Turley
H
H
Talks
K L
KL
Maxwell
P H
PH
Pugh
C W
CW
Ratcliffe
P J
PJ
Harris
A L
AL
D015153:Blotting, Western; D002256:Carbonic Anhydrases / Q000096:biosynthesis / Q000378:metabolism*; D002277:Carcinoma / Q000378:metabolism; D002292:Carcinoma, Renal Cell / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D016228:Endothelial Growth Factors / Q000378:metabolism; D017930:Genes, Reporter; D006801:Humans; D000860:Hypoxia; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D015151:Immunoblotting; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007680:Kidney Neoplasms / Q000378:metabolism; D008222:Lymphokines / Q000378:metabolism; D008957:Models, Genetic; D009336:Necrosis; D009593:Nitroimidazoles / Q000494:pharmacology; D009687:Nuclear Proteins / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology; D012878:Skin Neoplasms / Q000378:metabolism; D014157:Transcription Factors; D014407:Tumor Cells, Cultured; D015854:Up-Regulation; D001749:Urinary Bladder Neoplasms / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D004268:DNA-Binding Proteins; D016228:Endothelial Growth Factors; C497442:HIF1A protein, human; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008222:Lymphokines; D009593:Nitroimidazoles; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011838:Radiation-Sensitizing Agents; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C033815:pimonidazole; D012313:RNA; D002256:Carbonic Anhydrases; D010100:Oxygen