HIF-1alpha, STAT3, CBP/p300 and Ref-1/APE are components of a transcriptional complex that regulates Src-dependent hypoxia-induced expression of VEGF in pancreatic and prostate carcinomas.
Hypoxia stimulates a number of pathways critical to cancer cell survival, including the activation of vascular endothelial growth factor (VEGF) transcription. In normal fibroblasts, hypoxia-induced activation of the protein tyrosine kinase, Src, is required for VEGF expression. We show here in both pancreatic and prostate carcinoma cell lines cobalt chloride (used to mimic hypoxia) -induced VEGF expression requires Src activation and leads to increased steady-state levels of HIF-1alpha and increased phosphorylation of signal and transducer of transcription 3 (STAT3). STAT3 and hypoxia-inducible factor (HIF)-1alpha bind simultaneously to the VEGF promoter, where they form a molecular complex with the transcription coactivators CBP/p300 and Ref-1/APE. Expression of activated Src from an inducible promoter is sufficient to increase VEGF expression and form these STAT3/HIF-1alpha-containing promoter complexes. Inhibition of DNA binding by expression of either STAT3 or HIF-1alpha dominant negative mutants significantly reduces VEGF expression. These data suggest that the binding of both STAT3 and HIF-1alpha to the VEGF promoter is required for maximum transcription of VEGF mRNA following hypoxia.
Gray
Michael J
MJ
Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, 1515 Holcomb Boulevard, Houston, TX 77030, USA.
Zhang
Jing
J
Ellis
Lee M
LM
Semenza
Gregg L
GL
Evans
Douglas B
DB
Watowich
Stephanie S
SS
Gallick
Gary E
GE
D001345:Autoradiography; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D003035:Cobalt / Q000494:pharmacology; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000096:biosynthesis*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004789:Enzyme Activation; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D015151:Immunoblotting; D047468:Immunoprecipitation; D008156:Luciferases / Q000378:metabolism; D008297:Male; D008856:Microscopy, Fluorescence; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000378:metabolism; D009389:Neovascularization, Pathologic; D009687:Nuclear Proteins / Q000096:biosynthesis*; D010190:Pancreatic Neoplasms / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism; D050796:STAT3 Transcription Factor; D015398:Signal Transduction; D015534:Trans-Activators / Q000096:biosynthesis* / Q000378:metabolism*; D014157:Transcription Factors / Q000096:biosynthesis*; D014158:Transcription, Genetic; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism
D004268:DNA-Binding Proteins; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D003035:Cobalt; D008156:Luciferases; D019061:src-Family Kinases; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; C018021:cobaltous chloride