title: Fibulin-5 inhibits hepatocellular carcinoma cell migration and invasion by down-regulating matrix metalloproteinase-7 expression.
abstract: BACKGROUND
  Fibulin-5 has been considered as a tumor suppressor through inhibiting tumor growth and invasion. Reduced expression of Fibulin-5 is frequently observed in various human cancers. In this study, we investigate the clinical significance of Fibulin-5 and its role in hepatocellular carcinoma (HCC) cell migration and invasion.
  
  
  METHODS
  The expression of Fibulin-5 was evaluated by qRT-PCR and immunoblotting in HCC and matched noncancerous tissues. Fibulin-5 was over-expressed or knocked down by a retrovirus-mediated expression plasmid or a specific siRNA in HCC cells. Boyden chamber and Transwell assays were used to test HCC cell migration and invasion. Immunostaining was performed to determine matrix metalloproteinase-7 (MMP-7) expression in HCC specimens. MMP-7 retroviruses and siRNA were used to alter MMP-7 expression in HCC cells.
  
  
  RESULTS
  In our study, the expression levels of Fibulin-5 protein and mRNA were down-regulated in HCC tissues as compared with those in matched noncancerous tissues. Reduced expression of Fibulin-5 was observed in all HCC cell lines (HepG2, SMMC-7721, MHCC97L, Hep3B, MHCC97H and HCC-LM3) as compare with that in a non-transformed hepatic cell line (LO2). Low expression of Fibulin-5 was significantly correlated with poor prognostic features including multiple tumor nodes, venous infiltration, high Edmondson-Steiner grading and advanced tumor-node-metastasis (TNM) tumor stage. Furthermore, we demonstrated that Fibulin-5 was a novel independent prognostic marker for predicting 5-year survival of HCC patients. Our in vitro studies showed that Fibulin-5 overexpression inhibited HCC cell migration and invasion. While Fibulin-5 knockdown increased the number of migrated and invaded HCC cells. Fibulin-5 negatively regulated MMP-7 abundance in HCC cells. Moreover, the inverse correlation between Fibulin-5 and MMP-7 expressions was observed in HCC tissues. Mechanistically, we disclosed that MMP-7 knockdown reduced the number of migrated and invaded HCC cells. Restoring MMP-7 expression abrogated the suppressive effect of Fibulin-5 on HCC cell migration and invasion in vitro, suggesting that Fibulin-5 exerted its anti-metastatic function, at least in part, by down-regulating the expression of MMP-7 in HCC cells.
  
  
  CONCLUSIONS
  These results indicate that Fibulin-5 may serve as a prognostic biomarker and inhibits HCC invasion and metastasis by suppressing MMP-7 expression.
authors.affiliation: Department of Hepatobiliary Surgery, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, PR China. tks0912@foxmail.com.
authors.forename: Kangsheng
authors.initials: K
authors.lastname: Tu
authors.forename: Changwei
authors.initials: C
authors.lastname: Dou
authors.forename: Xin
authors.initials: X
authors.lastname: Zheng
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Yingmin
authors.initials: Y
authors.lastname: Yao
authors.forename: Qingguang
authors.initials: Q
authors.lastname: Liu
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology*; D054443:Cell Migration Assays; D002465:Cell Movement; D015536:Down-Regulation; D016326:Extracellular Matrix Proteins / Q000032:analysis / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D056945:Hep G2 Cells; D006801:Humans; D008099:Liver / Q000737:chemistry; D008113:Liver Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology* / Q000556:secondary; D015182:Lymphatic Irradiation; D008297:Male; D020783:Matrix Metalloproteinase 7 / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D012333:RNA, Messenger / Q000032:analysis*; D015996:Survival Rate; D047368:Tumor Burden
chemical_list: D014408:Biomarkers, Tumor; D016326:Extracellular Matrix Proteins; C492373:FBLN5 protein, human; D012333:RNA, Messenger; D020783:Matrix Metalloproteinase 7