title: Elevated autocrine EDIL3 protects hepatocellular carcinoma from anoikis through RGD-mediated integrin activation.
abstract: BACKGROUND
  A remolded microenvironment in hepatocellular carcinoma (HCC) caused by abnormally expressed matricellular proteins could promote HCC progression. The cell-matrix interactions mediated by integrins play an important role in tumor microenvironment. Epidermal Growth Factor-like repeats and Discoidin I-Like Domains 3 (EDIL3), an extracellular matrix (ECM) protein with angiogenic and anti-inflammatory effects, is abnormally highly expressed in HCC. Here we aim to analyze its expression in liver and HCC tissues, investigate the underlined mechanisms accounted for HCC progression.
  
  
  METHODS
  EDIL3 expression level is examined in normal liver, cirrhotic liver and HCC at both mRNA and protein level. The association between EDIL3 and clinical outcomes is analyzed. The pattern of EDIL3 expression and location is examined using Immunofluorescence and ELISA. Overexpression or knock-down of EDIL3 in a panel of cell lines are subjected to assays related to proliferation, invasion, and anoikis to investigate the mechanisms of this matrix protein in HCC progression. Recombinant EDIL3 treatment is applied to confirm the results.
  
  
  RESULTS
  Compared with normal liver and cirrhotic liver, EDIL3 is elevated in HCC. High level of EDIL3 protein is much more commonly in patients with larger tumor or portal vein tumor thrombus (PVTT) formation, associated with poor prognosis. EDIL3 is abundantly expressed in HCC cells and secreted by cancer cells. In vitro and in vivo studies indicate that EDIL3, probably in an autocrine manner, inhibits anoikis and promotes anchorage-independent growth of HCC cells. Further mechanistic studies suggest integrin ligation by EDIL3 and thus that the sustained activation of the FAK-Src-AKT signal is responsible for the anoikis resistance and anchorage independence. Both the administration of cilengitide, a RGD-containing integrin antagonist, and silencing of integrin αV, an important RGD-binding integrin, results in the blockade of anoikis-resistance induced by EDIL3.
  
  
  CONCLUSIONS
  Our study suggests that high levels of autocrine EDIL3 may contribute to a receptive microenvironment for the survival of detached HCC cells and may involve in cancer cell spreading. We also highlight the importance of interaction between EDIL3 and integrin αV and suggest disrupting the ligation of EDIL3 to integrins via RGD-blocking in selected patients may bear potential therapeutic value.
authors.forename: Ming-Xuan
authors.initials: MX
authors.lastname: Feng
authors.forename: Ming-Ze
authors.initials: MZ
authors.lastname: Ma
authors.forename: Ying
authors.initials: Y
authors.lastname: Fu
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Xue
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Zhang
authors.forename: Wen-Xin
authors.initials: WX
authors.lastname: Qin
authors.forename: Jian-Ren
authors.initials: JR
authors.lastname: Gu
authors.affiliation: Department of Liver Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pujian Road, Shanghai, Shanghai 200127, China. zzhang@shsci.org.
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Zhang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Xia
mesh_terms: D000818:Animals; D023102:Anoikis / Q000235:genetics; D019898:Autocrine Communication / Q000235:genetics; D002135:Calcium-Binding Proteins; D063646:Carcinogenesis / Q000473:pathology; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D006801:Humans; D039564:Integrin alphaV / Q000378:metabolism*; D008113:Liver Neoplasms / Q000098:blood supply / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008819:Mice, Nude; D008875:Middle Aged; D009842:Oligopeptides / Q000378:metabolism*; D011169:Portal Vein / Q000473:pathology; D011379:Prognosis; D015203:Reproducibility of Results; D015398:Signal Transduction; D013927:Thrombosis / Q000473:pathology; D015854:Up-Regulation / Q000235:genetics
chemical_list: D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D015815:Cell Adhesion Molecules; C110183:EDIL3 protein, human; D039564:Integrin alphaV; D009842:Oligopeptides; C047981:arginyl-glycyl-aspartic acid