Epidermal growth factor enhances insulin-like growth factor binding protein-1 synthesis in human hepatoma cells.
Epidermal growth factor (EGF) was found to induce a rapid 2-fold increase in the amount of insulin-like growth factor binding protein-1 (IGFBP-1) mRNA in human hepatoma Hep2G cells, and this was accompanied by a 2-fold increase in IGFBP-1 secretion. A protein synthesis inhibitor cycloheximide (CHX) caused a 2-3-fold increase in the amount of IGFBP-1 mRNA, which could be accounted for the observed stabilization in decay of IGFBP-1 mRNA after CHX treatment. In nuclear run-on transcription experiments neither EGF nor CHX affected the transcription rate of the IGFBP-1 gene. It is concluded that EGF increases IGFBP-1 secretion rapidly by enhancing IGFBP-1 mRNA accumulation, and the addition of a protein synthesis inhibitor results in a specific increment of IGFBP-1 mRNA, suggesting that a labile protein repressor protein is involved in the turnover IGFBP-1 mRNA.
D015152:Blotting, Northern; D006528:Carcinoma, Hepatocellular; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D015342:DNA Probes; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1; D007700:Kinetics; D008113:Liver Neoplasms; D012333:RNA, Messenger / Q000378:metabolism*; D013002:Somatomedins / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured
D002352:Carrier Proteins; D015342:DNA Probes; D018970:Insulin-Like Growth Factor Binding Protein 1; D012333:RNA, Messenger; D013002:Somatomedins; D004815:Epidermal Growth Factor; D003513:Cycloheximide