title: Down-regulation of SIX3 is associated with clinical outcome in lung adenocarcinoma.
abstract: BACKGROUND
  Lung cancer is a common cancer and the leading cause of cancer-related death worldwide. SIX3 is a human homologue of the highly conserved sine oculis gene family essential during embryonic development in vertebrates, and encodes a homeo-domain containing transcription factor. Little is known about the role of SIX3 in human tumorigenesis. This study is to assess the expression/function of SIX3 and the significance of SIX3 as a prognostic biomarker in lung adenocarcinoma.
  
  
  METHODS
  Quantitative real-time RT-PCR was used to analyze SIX3 mRNA expression and quantitative methylation specific PCR (MSP) was used to examine promoter methylation. MTS and colony formation assays were performed to examine cell proliferation. Wound healing assays were used to assess cell migration, and microarrays were utilized to examine genes regulated by SIX3 in lung cancer cells. Association of SIX3 expression levels with clinical outcomes of patients with lung adenocarcinoma was evaluated using the Kaplan-Meier method and a multivariate Cox proportional hazards regression model.
  
  
  RESULTS
  SIX3 was down-regulated in lung adenocarcinoma tissues compared to their matched adjacent normal tissues, and this down-regulation was associated with methylation of the SIX3 promoter. SIX3 was also methylation-silenced in lung cancer cell lines. Restoration of SIX3 in lung cancer cells lacking endogenous SIX3 suppressed cell proliferation and migration, and downregulated a number of genes involved in proliferation and metastasis such as S100P, TGFB3, GINS3 and BAG1. Moreover, SIX3 mRNA expression was associated with significantly improved overall survival (OS) and progression-free survival (PFS) in adenocarcinoma patients and patients with bronchioloalveolar carcinoma (BAC) features.
  
  
  CONCLUSIONS
  SIX3 may play an important role as a novel suppressor in human lung cancer. SIX3 has potential as a novel prognostic biomarker for patients with lung adenocarcinomas.
authors: School of Life Sciences, Tsinghua University, Beijing, China.
authors: Min-Li
authors: ML
authors: Mo
authors: Junichi
authors: J
authors: Okamoto
authors: Zhao
authors: Z
authors: Chen
authors: Tomomi
authors: T
authors: Hirata
authors: Iwao
authors: I
authors: Mikami
authors: Geneviève
authors: G
authors: Bosco-Clément
authors: Hui
authors: H
authors: Li
authors: Hai-Meng
authors: HM
authors: Zhou
authors: David M
authors: DM
authors: Jablons
authors: Biao
authors: B
authors: He
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000401:mortality / Q000601:surgery; D000077192:Adenocarcinoma of Lung; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000401:mortality / Q000601:surgery; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D019175:DNA Methylation; D018572:Disease-Free Survival; D015536:Down-Regulation; D005136:Eye Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000601:surgery; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D011379:Prognosis; D011401:Promoter Regions, Genetic; D016016:Proportional Hazards Models; D059467:Transcriptome; D016896:Treatment Outcome; D000097607:Homeobox Protein SIX3
chemical_list: D014408:Biomarkers, Tumor; D005136:Eye Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D000097607:Homeobox Protein SIX3
references: Microsc Res Tech. 2003 Apr 15;60(6):552-9
references: 12645003
references: Clin Cancer Res. 2003 Apr;9(4):1370-5
references: 12684406
references: Lancet. 2012 Mar 3;379(9818):823-32
references: 22285053
references: Cancer Lett. 2012 Dec 28;325(2):220-6
references: 22796605
references: J Clin Oncol. 2007 May 10;25(14):1898-907
references: 17488989
references: Int J Cancer. 2005 Sep 20;116(5):720-5
references: 15849750
references: Stat Med. 1996 Feb 28;15(4):361-87
references: 8668867
references: Curr Opin Pulm Med. 2007 Jul;13(4):290-6
references: 17534175
references: Lancet Oncol. 2009 Oct;10(10):1001-10
references: 19796752
references: Genome Biol. 2004;5(10):R80
references: 15461798
references: N Engl J Med. 2007 Feb 22;356(8):800-8
references: 17314339
references: Cancer. 2006 Apr 25;108(2):129-34
references: 16444703
references: Stat Appl Genet Mol Biol. 2004;3:Article3
references: 16646809
references: CA Cancer J Clin. 2007 Jan-Feb;57(1):43-66
references: 17237035
references: Int J Biochem Cell Biol. 2001 Jul;33(7):637-68
references: 11390274
references: Clin Cancer Res. 2002 Sep;8(9):2883-9
references: 12231532
references: J Cancer Res Clin Oncol. 2006 Dec;132(12):765-70
references: 16810501
references: Biochem Biophys Res Commun. 2004 Oct 1;322(4):1111-22
references: 15336958
references: Front Biosci. 2002 May 01;7:d1356-68
references: 11991838
references: Biochem Biophys Res Commun. 2010 Feb 5;392(2):150-4
references: 20059967
references: Clin Lung Cancer. 2006 Mar;7(5):313-22
references: 16640802
references: Nat Med. 2002 Aug;8(8):816-24
references: 12118244
references: Cancer Res. 2004 Jul 1;64(13):4442-52
references: 15231653
references: Cancer Res. 2006 Aug 1;66(15):7466-72
references: 16885343
references: Development. 2003 Jan;130(1):185-95
references: 12441302
references: J Clin Oncol. 2007 Dec 10;25(35):5562-9
references: 18065728
references: Proc Natl Acad Sci U S A. 2007 Mar 27;104(13):5527-32
references: 17369352
references: Lancet Oncol. 2007 Oct;8(10):889-97
references: 17851129
references: Cancer Res. 2008 Jun 1;68(11):4277-86
references: 18519687
references: Clin Cancer Res. 2006 Jun 15;12(12):3698-704
references: 16778095
references: Lancet Oncol. 2001 Sep;2(9):533-43
references: 11905707
references: Bioinformatics. 2003 Jan 22;19(2):185-93
references: 12538238
references: N Engl J Med. 2007 Jan 4;356(1):11-20
references: 17202451
references: J Thorac Cardiovasc Surg. 2008 Mar;135(3):627-34
references: 18329483
references: Clin Lung Cancer. 2011 Jul;12(4):237-44
references: 21726823
references: Cancer Biol Ther. 2010 May 15;9(10):832-40
references: 20404511
references: J Clin Invest. 2007 Nov;117(11):3436-44
references: 17948124