title: Novel role for epidermal growth factor-like domain 7 in metastasis of human hepatocellular carcinoma.
abstract: Epidermal growth factor-like domain 7 (Egfl7) is a recently identified secreted protein that is believed to be primarily expressed in endothelial cells (ECs). Although its expression was reported elevated during tumorigenesis, whether and how Egfl7 contributes to human malignancies remains unknown. In the present study overexpression of Egfl7 was found predominantly in hepatocellular carcinoma (HCC) cells in HCC tissues and closely correlated with poor prognosis of HCC. The expression of Egfl7 in cancer cells was further verified with HCC cell lines including HepG2, MHCC97-L, and HCCLM3, and the Egfl7 expression levels positively correlated with metastatic potential of HCC cell lines was tested. To functionally characterize Egfl7 in HCC, we depleted its expression in HCCLM3 cells by using small interfering RNA. Interestingly, reduction of Egfl7 expression resulted in significant inhibition of migration but not growth of HCCLM3 cells. Biochemical analysis indicated that Egfl7 could facilitate the phosphorylation of focal adhesion kinase (FAK) and therefore promote the migration of HCCLM3 cells. In addition, this effect was almost completely blocked by inhibition of epidermal growth factor receptor (EGFR), indicating that the activation of FAK by Egfl7 is mediated through EGFR. Finally, we used a mouse model to demonstrate that down-regulation of Egfl7 was associated with suppression of intrahepatic and pulmonary metastases of HCC. Collectively, our study shows for the first time that overexpression of Egfl7 in HCC and Egfl7 promotes metastasis of HCC by enhancing cell motility through EGFR-dependent FAK phosphorylation.
  
  
  CONCLUSIONS
  Our study suggests Egfl7 as a novel prognostic marker for metastasis of HCC and a potential therapeutic target.
authors.affiliation: Liver Cancer Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Wu
authors.forename: Lian-Yue
authors.initials: LY
authors.lastname: Yang
authors.forename: Yun-Feng
authors.initials: YF
authors.lastname: Li
authors.forename: Di-Peng
authors.initials: DP
authors.lastname: Ou
authors.forename: Dong-Ping
authors.initials: DP
authors.lastname: Chen
authors.forename: Chun
authors.initials: C
authors.lastname: Fan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D002135:Calcium-Binding Proteins; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D066255:EGF Family of Proteins; D016228:Endothelial Growth Factors / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D005260:Female; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D010766:Phosphorylation; D011379:Prognosis
chemical_list: D002135:Calcium-Binding Proteins; D066255:EGF Family of Proteins; C527877:EGFL7 protein, human; D016228:Endothelial Growth Factors; D051416:Focal Adhesion Protein-Tyrosine Kinases