title: Glucose deprivation increases mRNA stability of vascular endothelial growth factor through activation of AMP-activated protein kinase in DU145 prostate carcinoma.
abstract: The induction of proangiogenic cytokines such as vascular endothelial growth factor (VEGF) is a critical feature of tumor angiogenesis. In the present study, we examined the mechanisms of VEGF gene expression induced by glucose deprivation in cancer cells, a role of AMP-activated protein kinase (AMPK) in the process, and the signal transduction pathway. AMPK functions as an energy sensor to provide metabolic adaptation under ATP-depleting conditions such as hypoxia and nutritional deprivation. Here, we show that glucose deprivation leads to a significant increase in the mRNA level of VEGF, GLUT1, and PFKFB3 genes in several cancer cells via a hypoxia-inducible factor-1-independent mechanism, and we demonstrate an essential role of AMPK in these gene expressions. Our data suggest that VEGF mRNA induction by glucose deprivation is due to an increase in mRNA stability, and the AMPK activity is necessary and sufficient to confer the stability to VEGF mRNA. We further show that reactive oxygen species is involved in glucose deprivation-induced AMPK activity in DU145 human prostate carcinomas, and c-Jun amino-terminal kinase acts as an upstream component in AMPK activation cascades under these conditions. LKB1, which was recently identified as a direct upstream kinase of AMPK, was not detected in DU145 cells. In conclusion, our results demonstrate a novel and major role of AMPK in the post-transcriptional regulation of VEGF, further implying its potential role in tumor angiogenesis.
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical Research Center for Bioreaction to Reactive Oxygen Species, Kyung Hee University College of Medicine, Seoul 130-701, Korea.
authors.forename: Hee
authors.initials: H
authors.lastname: Yun
authors.forename: Minyoung
authors.initials: M
authors.lastname: Lee
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Kim
authors.forename: Joohun
authors.initials: J
authors.lastname: Ha
mesh_terms: D055372:AMP-Activated Protein Kinases; D000255:Adenosine Triphosphate / Q000737:chemistry; D000256:Adenoviridae / Q000235:genetics; D015152:Blotting, Northern; D015153:Blotting, Western; D045744:Cell Line, Tumor; D016207:Cytokines / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D004797:Enzyme-Linked Immunosorbent Assay; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D005947:Glucose / Q000378:metabolism*; D051272:Glucose Transporter Type 1; D006367:HeLa Cells; D006801:Humans; D000860:Hypoxia; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008297:Male; D008957:Models, Genetic; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism*; D009389:Neovascularization, Pathologic; D009687:Nuclear Proteins / Q000378:metabolism; D025481:Phosphofructokinase-2; D011471:Prostatic Neoplasms / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism; D012313:RNA / Q000737:chemistry; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism*; D017382:Reactive Oxygen Species; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: D016207:Cytokines; D004268:DNA-Binding Proteins; D051272:Glucose Transporter Type 1; C497442:HIF1A protein, human; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009004:Monosaccharide Transport Proteins; D009097:Multienzyme Complexes; D009687:Nuclear Proteins; D011506:Proteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; C495677:SLC2A1 protein, human; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D012313:RNA; D000255:Adenosine Triphosphate; C107345:PFKFB3 protein, human; D025481:Phosphofructokinase-2; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; D005947:Glucose