title: MicroRNA cluster 221-222 and estrogen receptor alpha interactions in breast cancer.
abstract: BACKGROUND
  Several lines of evidence have suggested that estrogen receptor alpha (ERalpha)-negative breast tumors, which are highly aggressive and nonresponsive to hormonal therapy, arise from ERalpha-positive precursors through different molecular pathways. Because microRNAs (miRNAs) modulate gene expression, we hypothesized that they may have a role in ER-negative tumor formation.
  
  
  METHODS
  Gene expression profiles were used to highlight the global changes induced by miRNA modulation of ERalpha protein. miRNA transfection and luciferase assays enabled us to identify new targets of miRNA 206 (miR-206) and miRNA cluster 221-222 (miR-221-222). Northern blot, luciferase assays, estradiol treatment, and chromatin immunoprecipitation were performed to identify the miR-221-222 transcription unit and the mechanism implicated in its regulation.
  
  
  RESULTS
  Different global changes in gene expression were induced by overexpression of miR-221-222 and miR-206 in ER-positive cells. miR-221 and -222 increased proliferation of ERalpha-positive cells, whereas miR-206 had an inhibitory effect (mean absorbance units [AU]: miR-206: 500 AU, 95% confidence interval [CI]) = 480 to 520; miR-221: 850 AU, 95% CI = 810 to 873; miR-222: 879 AU, 95% CI = 850 to 893; P < .05). We identified hepatocyte growth factor receptor and forkhead box O3 as new targets of miR-206 and miR-221-222, respectively. We demonstrated that ERalpha negatively modulates miR-221 and -222 through the recruitment of transcriptional corepressor partners: nuclear receptor corepressor and silencing mediator of retinoic acid and thyroid hormone receptor.
  
  
  CONCLUSIONS
  These findings suggest that the negative regulatory loop involving miR-221-222 and ERalpha may confer proliferative advantage and migratory activity to breast cancer cells and promote the transition from ER-positive to ER-negative tumors.
authors.affiliation: Department of Molecular Virology, Immunology and Medical Genetics and Comprehensive Cancer Center, Ohio State University, 460 West, 12th Ave, Columbus, OH 43210, USA.
authors.forename: Gianpiero
authors.initials: G
authors.lastname: Di Leva
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Gasparini
authors.forename: Claudia
authors.initials: C
authors.lastname: Piovan
authors.forename: Apollinaire
authors.initials: A
authors.lastname: Ngankeu
authors.forename: Michela
authors.initials: M
authors.lastname: Garofalo
authors.forename: Cristian
authors.initials: C
authors.lastname: Taccioli
authors.forename: Marilena V
authors.initials: MV
authors.lastname: Iorio
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.forename: Stefano
authors.initials: S
authors.lastname: Volinia
authors.forename: Hansjuerg
authors.initials: H
authors.lastname: Alder
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nakamura
authors.forename: Gerard
authors.initials: G
authors.lastname: Nuovo
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Liu
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Nephew
authors.forename: Carlo M
authors.initials: CM
authors.lastname: Croce
mesh_terms: D015152:Blotting, Northern; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D047369:Chromatin Immunoprecipitation; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018734:Genes, erbB-2; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D046228:Microarray Analysis; D010957:Plasmids; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D015854:Up-Regulation
chemical_list: D047628:Estrogen Receptor alpha; D035683:MicroRNAs; D012333:RNA, Messenger; C506487:ESR1 protein, human; C546087:MIRN206 microRNA, human; C525709:MIR221, human; C525710:MIR222, human
references.citation: Oncol Rep. 1998 Sep-Oct;5(5):1013-24
references.pmid: 9683803
references.citation: Proc Natl Acad Sci U S A. 2010 Jan 5;107(1):264-9
references.pmid: 20018759
references.citation: J Biol Chem. 2008 Nov 7;283(45):31079-86
references.pmid: 18790736
references.citation: J Steroid Biochem Mol Biol. 2002 Feb;80(2):239-56
references.pmid: 11897507
references.citation: J Mammary Gland Biol Neoplasia. 2001 Apr;6(2):183-92
references.pmid: 11501578
references.citation: Oncogene. 2001 May 28;20(24):3110-5
references.pmid: 11420727
references.citation: Mol Endocrinol. 2008 Feb;22(2):388-402
references.pmid: 18006642
references.citation: Cancer Res. 2006 Apr 1;66(7):3903-11
references.pmid: 16585219
references.citation: Clin Cancer Res. 2009 Feb 1;15(3):752-7
references.pmid: 19188143
references.citation: J Mammary Gland Biol Neoplasia. 2004 Jan;9(1):55-66
references.pmid: 15082918
references.citation: J Biol Chem. 2006 Jun 16;281(24):16272-8
references.pmid: 16608856
references.citation: Genome Res. 2007 Oct;17(10):1537-45
references.pmid: 17785539
references.citation: Mol Cell. 2007 Sep 7;27(5):691-700
references.pmid: 17803935
references.citation: FEBS J. 2009 Jun;276(12):3269-76
references.pmid: 19438724
references.citation: Cancer Res. 2005 Aug 15;65(16):7065-70
references.pmid: 16103053
references.citation: J Biol Chem. 2008 Oct 31;283(44):29897-903
references.pmid: 18708351
references.citation: EMBO J. 2007 Aug 8;26(15):3699-708
references.pmid: 17627278
references.citation: Cancer Invest. 2004;22(4):588-603
references.pmid: 15565817
references.citation: Oncogene. 2008 Sep 25;27(43):5651-61
references.pmid: 18521080
references.citation: Oncogene. 2005 Nov 14;24(50):7410-25
references.pmid: 16288288
references.citation: Breast Cancer Res. 2004;6(6):240-5
references.pmid: 15535853
references.citation: Mol Endocrinol. 2002 Oct;16(10):2231-42
references.pmid: 12351689
references.citation: Nat Rev Cancer. 2006 Mar;6(3):184-92
references.pmid: 16453012
references.citation: Proc Natl Acad Sci U S A. 2000 Aug 29;97(18):10101-6
references.pmid: 10963673
references.citation: Lancet. 1985 Feb 16;1(8425):364-6
references.pmid: 2857419
references.citation: J Cell Biol. 2006 Aug 28;174(5):677-87
references.pmid: 16923828
references.citation: Oncogene. 2008 Oct 23;27(49):6322-33
references.pmid: 18663362
references.citation: Oncogene. 2008 Jun 19;27(27):3845-55
references.pmid: 18246122
references.citation: Clin Cancer Res. 2009 Feb 15;15(4):1126-32
references.pmid: 19228717
references.citation: Breast Cancer Res Treat. 2007 Jun;103(2):239-46
references.pmid: 17004110
references.citation: Cancer Res. 2008 Jul 1;68(13):5004-8
references.pmid: 18593897
references.citation: J Cell Biochem. 2008 Aug 15;104(6):2091-106
references.pmid: 18393360
references.citation: Oncogene. 1998 Mar;16(11):1391-7
references.pmid: 9525738
references.citation: Nature. 2004 Sep 16;431(7006):350-5
references.pmid: 15372042
references.citation: Mol Endocrinol. 2007 May;21(5):1132-47
references.pmid: 17312270
references.citation: Cancer Cell. 2009 Dec 8;16(6):498-509
references.pmid: 19962668
references.citation: J Immunol. 2002 May 15;168(10):5024-31
references.pmid: 11994454
references.citation: Nature. 2004 Nov 11;432(7014):235-40
references.pmid: 15531877
references.citation: Nat Rev Cancer. 2006 Nov;6(11):857-66
references.pmid: 17060945
references.citation: Proc Natl Acad Sci U S A. 2009 Aug 4;106(31):12909-14
references.pmid: 19567831
references.citation: Mol Endocrinol. 2001 Aug;15(8):1344-59
references.pmid: 11463858
references.citation: Mol Endocrinol. 2009 Aug;23(8):1215-30
references.pmid: 19423651
references.citation: Oncogene. 1998 Jul 30;17(4):425-32
references.pmid: 9696035