title: Activation of p21CIP1/WAF1 gene expression and inhibition of cell proliferation by overexpression of hepatocyte nuclear factor-4alpha.
abstract: The F9 murine embryonal carcinoma cell line provides an attractive system for studying epithelial differentiation and antiproliferative processes. We have recently established F9 cells expressing doxycycline-inducible hepatocyte nuclear factor (HNF)-4alpha and shown that HNF-4alpha triggers the gene expression of tight-junction molecules, occludin, claudin-6, and claudin-7, as well as formation of functional tight junctions and polarized epithelial morphology (Exp. Cell Res. 286, [2003] 288). Since these events were very similar to those induced by retinoids, we investigated whether HNF-4alpha, like retinoid receptors, was involved in the control of cell proliferation. We herein show that HNF-4alpha up-regulates expression of the p21 gene, but not the p15, p16, p18, p19, or p27 gene, in a p53-independent manner, and inhibits cell growth in F9 cells. Similar results were observed in rat lung endothelial cells, in which expression of HNF-4alpha is conditionally induced by doxycycline. Furthermore, we demonstrate, by reporter assay, that HNF-4alpha significantly elevates the transcriptional activity of the p21 promoter. Since, HNF-4alpha is expressed not only in the liver but also in organs containing epithelial cells, such as kidney, intestine, pancreas, and stomach, it might also play critical roles in the regulation of epithelial morphogenesis and proliferation in these organs.
authors.affiliation: Department of Pathology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan. hidchiba@sapmed.ac.jp
authors.forename: Hideki
authors.initials: H
authors.lastname: Chiba
authors.forename: Taisei
authors.initials: T
authors.lastname: Itoh
authors.forename: Seiro
authors.initials: S
authors.lastname: Satohisa
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Sakai
authors.forename: Hiroko
authors.initials: H
authors.lastname: Noguchi
authors.forename: Makoto
authors.initials: M
authors.lastname: Osanai
authors.forename: Takashi
authors.initials: T
authors.lastname: Kojima
authors.forename: Norimasa
authors.initials: N
authors.lastname: Sawada
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics*; D002455:Cell Division / Q000235:genetics; D002460:Cell Line; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics*; D004318:Doxycycline / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000235:genetics; D018816:Genes, cdc / Q000502:physiology; D051557:Hepatocyte Nuclear Factor 4; D051379:Mice; D038081:Organogenesis / Q000235:genetics*; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000235:genetics*; D051381:Rats; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics*; D015533:Transcriptional Activation / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics
chemical_list: C493957:Cdkn1a protein, mouse; C493958:Cdkn1a protein, rat; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004268:DNA-Binding Proteins; D051557:Hepatocyte Nuclear Factor 4; D010750:Phosphoproteins; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D004318:Doxycycline