title: Identification of proteins binding to E-Box/Ku86 sites and function of the tumor suppressor SAFB1 in transcriptional regulation of the human xanthine oxidoreductase gene.
abstract: The xanthine oxidoreductase gene (XOR) encodes an important source of reactive oxygen species and uric acid, and its expression is associated with various human diseases including several forms of cancer. We previously reported that basal human XOR (hXOR) expression is restricted or repressed by E-box and TATA-like elements and a cluster of transcriptional proteins, including AREB6-like proteins and DNA-dependent protein kinase (DNA-PK). We now demonstrate that the cluster contains the tumor suppressors SAFB1, BRG1, and SAF-A. We further demonstrate that SAFB1 silencing increases hXOR expression and that SAFB1 directly binds to the E-box. Multiple studies in vitro and in vivo including pulldown, immunoprecipitation and chromatin immunoprecipitation analyses indicate that SAFB1, Ku86, and BRG1 associate with each other. The results suggest that the SAFB1 complex binds to the hXOR promoter in a chromatin environment and plays a critical role in restricting hXOR expression via its direct interaction with the E-box, DNA-PK, and tumor suppressors. Moreover, we demonstrate that the cytokine, oncostatin M (OSM), induces the phosphorylation of SAFB1 and that the OSM-induced hXOR mRNA expression is significantly inhibited by silencing the DNA-PK catalytic subunit or SAFB1 expression. The present studies for the first time demonstrate that hXOR is a tumor suppressor-targeted gene and that the phosphorylation of SAFB1 is regulated by OSM, providing a molecular basis for understanding the role of SAFB1-regulated hXOR transcription in cytokine stimulation and tumorigenesis.
authors.affiliation: Department of Internal Medicine, Division of Respiratory, Critical Care, and Occupational Medicine, University of Utah Health Sciences Center and Veterans Affairs Medical Center, Salt Lake City, Utah 84132, USA.
authors.forename: Junji
authors.initials: J
authors.lastname: Lin
authors.forename: Ping
authors.initials: P
authors.lastname: Xu
authors.forename: Patricia
authors.initials: P
authors.lastname: LaVallee
authors.forename: John R
authors.initials: JR
authors.lastname: Hoidal
mesh_terms: D034961:Antigens, Nuclear / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D016207:Cytokines / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D000072200:Ku Autoantigen; D036961:Matrix Attachment Region Binding Proteins / Q000378:metabolism*; D008954:Models, Biological; D034521:Nuclear Matrix-Associated Proteins / Q000378:metabolism*; D053683:Oncostatin M / Q000378:metabolism*; D010766:Phosphorylation; D011960:Receptors, Estrogen / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry; D014158:Transcription, Genetic; D014968:Xanthine Dehydrogenase / Q000378:metabolism*
chemical_list: D034961:Antigens, Nuclear; D016207:Cytokines; D004268:DNA-Binding Proteins; D036961:Matrix Attachment Region Binding Proteins; D034521:Nuclear Matrix-Associated Proteins; D011960:Receptors, Estrogen; D011994:Recombinant Proteins; C109132:SAFB protein, human; D053683:Oncostatin M; D014968:Xanthine Dehydrogenase; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen
references.citation: Genes Dev. 1999 Apr 15;13(8):916-34
references.pmid: 10215620
references.citation: J Physiol. 2004 Mar 16;555(Pt 3):589-606
references.pmid: 14694147
references.citation: Nature. 2003 Oct 2;425(6957):516-21
references.pmid: 14520412
references.citation: Science. 1991 Dec 6;254(5037):1512-5
references.pmid: 1660188
references.citation: Ugeskr Laeger. 1994 Apr 18;156(16):2396-401
references.pmid: 8009701
references.citation: Toxicology. 2001 Mar 7;160(1-3):11-8
references.pmid: 11246119
references.citation: Cancer Res. 2004 Aug 1;64(15):5059-62
references.pmid: 15289304
references.citation: Mol Cell Biol. 1999 Jun;19(6):4065-78
references.pmid: 10330147
references.citation: Proc Soc Exp Biol Med. 1996 Apr;211(4):366-73
references.pmid: 8618943
references.citation: Basic Res Cardiol. 1987 Sep-Oct;82(5):486-92
references.pmid: 3426527
references.citation: Trends Genet. 1996 Jun;12(6):229-34
references.pmid: 8928228
references.citation: J Clin Invest. 1990 Mar;85(3):739-45
references.pmid: 2155924
references.citation: Biochem J. 1996 Sep 1;318 ( Pt 2):379-82
references.pmid: 8809022
references.citation: Am J Physiol. 1988 Dec;255(6 Pt 2):H1269-75
references.pmid: 3059826
references.citation: Chem Res Toxicol. 1999 Feb;12(2):180-6
references.pmid: 10027796
references.citation: Proc Natl Acad Sci U S A. 1990 Oct;87(19):7638-42
references.pmid: 2217195
references.citation: J Immunol. 1994 Aug 15;153(4):1789-97
references.pmid: 8046245
references.citation: J Biol Chem. 2004 Apr 16;279(16):16057-63
references.pmid: 14761964
references.citation: Oncogene. 2000 May 15;19(21):2628-37
references.pmid: 10851062
references.citation: J Biol Chem. 1969 Apr 10;244(7):1682-91
references.pmid: 5813728
references.citation: Trends Biochem Sci. 1994 Jan;19(1):38-42
references.pmid: 8140620
references.citation: Kidney Int. 1986 Feb;29(2):478-83
references.pmid: 3702206
references.citation: Cancer Lett. 2005 Sep 28;227(2):133-9
references.pmid: 16112416
references.citation: Nucleic Acids Res. 1996 Mar 1;24(5):843-9
references.pmid: 8600450
references.citation: J Biol Chem. 2001 May 18;276(20):16848-56
references.pmid: 11279128
references.citation: Biochem Soc Trans. 1993 Nov;21(4):930-5
references.pmid: 8132096
references.citation: Biochem Soc Trans. 1997 Aug;25(3):786-91
references.pmid: 9388546
references.citation: Curr Protoc Mol Biol. 2001 May;Chapter 10:Unit 10.16
references.pmid: 18265056
references.citation: Biochem Biophys Res Commun. 1994 Mar 15;199(2):998-1004
references.pmid: 8135849
references.citation: Eur J Biochem. 1997 May 1;245(3):541-8
references.pmid: 9182988
references.citation: Kidney Int. 1991 Dec;40(6):1041-9
references.pmid: 1662318
references.citation: Arch Biochem Biophys. 1976 Feb;172(2):365-79
references.pmid: 176940
references.citation: J Biol Chem. 1977 Oct 10;252(19):6721-8
references.pmid: 197102
references.citation: Br J Cancer. 1999 Aug;80(12):1968-73
references.pmid: 10471047
references.citation: Proc Natl Acad Sci U S A. 1981 Nov;78(11):6858-62
references.pmid: 6947260
references.citation: Biochem J. 1986 May 1;235(3):747-54
references.pmid: 3753442
references.citation: Proc Natl Acad Sci U S A. 2004 Nov 9;101(45):15944-8
references.pmid: 15486091
references.citation: Antioxid Redox Signal. 2000 Winter;2(4):903-17
references.pmid: 11213491
references.citation: Nucleic Acids Res. 1991 May 11;19(9):2499
references.pmid: 2041787
references.citation: Nutr Cancer. 2007;59(1):8-13
references.pmid: 17927496
references.citation: J Clin Invest. 1989 Apr;83(4):1137-43
references.pmid: 2539390
references.citation: AACN Clin Issues. 2002 Nov;13(4):540-9
references.pmid: 12473916
references.citation: Biochemistry (Mosc). 2000 Jan;65(1):2-27
references.pmid: 10702637
references.citation: Cancer Res. 2003 Feb 1;63(3):560-6
references.pmid: 12566296
references.citation: Kidney Int. 1991 Aug;40(2):291-301
references.pmid: 1942778
references.citation: Biochem J. 1992 Aug 1;285 ( Pt 3):1001-8
references.pmid: 1379796
references.citation: J Biol Chem. 1994 Jan 14;269(2):1449-59
references.pmid: 8288611
references.citation: EMBO J. 1992 Sep;11(9):3431-40
references.pmid: 1324173
references.citation: Pflugers Arch. 1989 Nov;415(2):127-35
references.pmid: 2556684
references.citation: Free Radic Biol Med. 2002 Sep 15;33(6):774-97
references.pmid: 12208366
references.citation: Am J Physiol. 1990 Mar;258(3 Pt 2):F711-6
references.pmid: 2316673
references.citation: J Biol Chem. 2000 Feb 25;275(8):5918-26
references.pmid: 10681584
references.citation: Chest. 1999 Jul;116(1 Suppl):56S-61S
references.pmid: 10424593
references.citation: Breast Cancer Res. 2000;2(2):116-24
references.pmid: 11250701
references.citation: Cancer Res. 2003 May 15;63(10):2440-6
references.pmid: 12750264
references.citation: Breast Cancer Res. 2002;4(2):70-6
references.pmid: 11879567
references.citation: Biochim Biophys Acta. 1989 Apr 25;991(1):79-84
references.pmid: 2713424
references.citation: J Biol Chem. 2002 Apr 5;277(14):11617-20
references.pmid: 11805123
references.citation: Curr Biol. 1999 Dec 16-30;9(24):R936-8
references.pmid: 10607581
references.citation: Genomics. 1994 Sep 1;23(1):289-91
references.pmid: 7829092
references.citation: J Clin Invest. 1992 Jan;89(1):197-202
references.pmid: 1370294
references.citation: FASEB J. 1996 May;10(7):709-20
references.pmid: 8635688
references.citation: Annu Rev Pharmacol Toxicol. 2004;44:239-67
references.pmid: 14744246
references.citation: Am J Physiol. 1994 Feb;266(2 Pt 1):L163-71
references.pmid: 8141312
references.citation: Mol Cell Biol. 2004 Jan;24(1):362-76
references.pmid: 14673169
references.citation: Free Radic Biol Med. 2002 Jun 1;32(11):1102-15
references.pmid: 12031895
references.citation: Free Radic Biol Med. 1999 Feb;26(3-4):348-54
references.pmid: 9895226
references.citation: Chem Res Toxicol. 2000 Aug;13(8):793-800
references.pmid: 10956068
references.citation: J Biol Chem. 1960 Dec;235:3544-50
references.pmid: 13716276
references.citation: Chem Res Toxicol. 2002 Apr;15(4):536-44
references.pmid: 11952340
references.citation: J Biol Chem. 1990 Aug 25;265(24):14170-5
references.pmid: 2387845
references.citation: Br J Cancer. 2001 Feb;84(4):493-8
references.pmid: 11207044
references.citation: Circ Res. 2004 Nov 26;95(11):1118-24
references.pmid: 15528468
references.citation: Genes Dev. 2002 Dec 15;16(24):3223-35
references.pmid: 12502743
references.citation: Expert Rev Mol Diagn. 2003 Sep;3(5):573-85
references.pmid: 14510178
references.citation: J Cell Physiol. 2003 Jul;196(1):19-41
references.pmid: 12767038
references.citation: J Appl Physiol (1985). 1987 Nov;63(5):2159-63
references.pmid: 2826385
references.citation: Eur J Biochem. 1995 Oct 1;233(1):73-82
references.pmid: 7588776
references.citation: Biochim Biophys Acta. 1992 Jul 21;1117(1):25-32
references.pmid: 1627588
references.citation: Cell Metab. 2007 Feb;5(2):115-28
references.pmid: 17276354