title: SPOCK1 is regulated by CHD1L and blocks apoptosis and promotes HCC cell invasiveness and metastasis in mice.
abstract: OBJECTIVE
  Chromodomain helicase/adenosine triphosphatase DNA binding protein 1-like (CHD1L) is an SNF2-like transcription factor involved in the development of human hepatocellular carcinoma (HCC). Sparc/osteonectin, cwcv, and kazal-like domains proteoglycan 1 (SPOCK1) is up-regulated by CHD1L; we investigated its role in hepatocellular carcinogenesis.
  
  
  METHODS
  We investigated interactions between SPOCK1 and CHD1L using electrophoretic mobility shift and luciferase reporter assays. Levels of SPOCK1 messenger RNA (mRNA) and protein were measured in samples of HCC and adjacent nontumor liver tissues (135 pairs) and compared using Pearson correlation coefficients. Effects of SPOCK1 overexpression and silencing were determined in HCC cell lines (QGY-7703, PLC-8024, BEL-7402, and QGY-7701).
  
  
  RESULTS
  The CHD1L protein bound directly to the promoter region (nt-1662 to +34) of SPOCK1 and activated transcription. Levels of SPOCK1 mRNA and protein were increased in 60% of human HCC samples, compared with nontumor live tissues, and was associated significantly with clinical stage. Levels of SPOCK1 mRNA were increased among tumors that became metastatic, compared with those that did not, and among patients with shorter overall and disease-free survival times. Ectopic expression of SPOCK1 in HCC cells increased proliferation, foci formation, and colony formation in soft agar; these cells also formed larger xenograft tumors, more rapidly, in nude mice than control HCC cells. Silencing SPOCK1 expression with short hairpin RNA had the opposite effects. We found that SPOCK1 prevents apoptosis of HCC cells by activating Akt, to block release of cytochrome c and activation of caspase-9 and caspase-3; these effects were reversed with an Akt inhibitor. HCC cells that overexpressed SPOCK1 expressed higher levels of matrix metallopeptidase 9, were more invasive in Matrigel assays, and formed more metastatic nodules in immunodeficient mice than control HCC cells.
  
  
  CONCLUSIONS
  CHD1L activates expression of SPOCK1, which activates Akt signaling to block apoptosis and invasion by HCC cells, in culture and in mice. Levels of SPOCK1 increase with progression of human HCC. SPOCK1 might be used as a prognostic factor or therapeutic target.
authors.affiliation: Department of Clinical Oncology, The University of Hong Kong, Hong Kong, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Leilei
authors.initials: L
authors.lastname: Chen
authors.forename: Tim Hon Man
authors.initials: TH
authors.lastname: Chan
authors.forename: Ming
authors.initials: M
authors.lastname: Liu
authors.forename: Kar-Lok
authors.initials: KL
authors.lastname: Kong
authors.forename: Ji-Liang
authors.initials: JL
authors.lastname: Qiu
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Yun-Fei
authors.initials: YF
authors.lastname: Yuan
authors.forename: Xin-Yuan
authors.initials: XY
authors.lastname: Guan
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D017209:Apoptosis; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology*; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D004265:DNA Helicases / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D018572:Disease-Free Survival; D005260:Female; D020868:Gene Silencing; D006801:Humans; D008099:Liver / Q000378:metabolism; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D051379:Mice; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011401:Promoter Regions, Genetic; D011509:Proteoglycans / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D004268:DNA-Binding Proteins; D011509:Proteoglycans; D012333:RNA, Messenger; C504369:SPOCK1 protein, human; C504370:Spock1 protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D053148:Caspase 3; D053453:Caspase 9; D020780:Matrix Metalloproteinase 9; D004265:DNA Helicases; C543585:CHD1L protein, human; C546393:Chd1l protein, mouse