title: Activation of signal transducer and activator of transcription-3 (Stat3) expression by interferon-gamma and interleukin-6 in hepatoma cells.
abstract: Signal Transducer and Activator of Transcription 3 (Stat3) is a latent protein activated in response to various cytokines and growth factors. It is believed that Stat3 is a key signaling molecule involved in the regulation of acute phase gene expression by interleukin 6 (IL-6) in hepatocytes. We report that both IL-6 and interferon gamma (IFN gamma) up-regulate the expression of Stat3 on both mRNA and protein levels in rat and human hepatoma cells. The effect of IL-6 and IFN gamma on Stat3 mRNA expression was time- and dose-dependent. Other factors, including IL-1, TNF alpha, EGF, Dexamethasone and PMA, did not have any effect on Stat3 mRNA expression. Moreover, we show that the rapid induction of Stat3 expression by IL-6 and IFN gamma was independent of ongoing protein synthesis, suggesting regulation by Stat3 and Stat1, respectively.
mesh_terms: D000209:Acute-Phase Proteins; D000818:Animals; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular; D004268:DNA-Binding Proteins / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D015850:Interleukin-6 / Q000494:pharmacology*; D008113:Liver Neoplasms; D008114:Liver Neoplasms, Experimental; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D050796:STAT3 Transcription Factor; D015534:Trans-Activators / Q000235:genetics*; D014407:Tumor Cells, Cultured
chemical_list: D000209:Acute-Phase Proteins; D004268:DNA-Binding Proteins; D015850:Interleukin-6; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C494088:Stat3 protein, rat; D015534:Trans-Activators; D007371:Interferon-gamma