title: MicroRNA-195 suppresses angiogenesis and metastasis of hepatocellular carcinoma by inhibiting the expression of VEGF, VAV2, and CDC42.
abstract: Hepatocellular carcinoma (HCC) is characterized by active angiogenesis and metastasis, which account for rapid recurrence and poor survival. There is frequent down-regulation of miR-195 expression in HCC tissues. In this study, the role of miR-195 in HCC angiogenesis and metastasis was investigated with in vitro capillary tube formation and transwell assays, in vivo orthotopic xenograft mouse models, and human HCC specimens. Reduction of miR-195 in HCC tissues was significantly associated with increased angiogenesis, metastasis, and worse recurrence-free survival. Both gain-of-function and loss-of-function studies of in vitro models revealed that miR-195 not only suppressed the ability of HCC cells to promote the migration and capillary tube formation of endothelial cells but also directly repressed the abilities of HCC cells to migrate and invade extracellular matrix gel. Based on mouse models, we found that the induced expression of miR-195 dramatically reduced microvessel densities in xenograft tumors and repressed both intrahepatic and pulmonary metastasis. Subsequent investigations disclosed that miR-195 directly inhibited the expression of the proangiogenic factor vascular endothelial growth factor (VEGF) and the prometastatic factors VAV2 and CDC42. Knockdown of these target molecules of miR-195 phenocopied the effects of miR-195 restoration, whereas overexpression of these targets antagonized the function of miR-195. Furthermore, we revealed that miR-195 down-regulation resulted in enhanced VEGF levels in the tumor microenvironment, which subsequently activated VEGF receptor 2 signaling in endothelial cells and thereby promoted angiogenesis. Additionally, miR-195 down-regulation led to increases in VAV2 and CDC42 expression, which stimulated VAV2/Rac1/CDC42 signaling and lamellipodia formation and thereby facilitated the metastasis of HCC cells.
  
  
  CONCLUSIONS
  miR-195 deregulation contributes to angiogenesis and metastasis in HCC. The restoration of miR-195 expression may be a promising strategy for HCC therapy.
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Ruizhi
authors.initials: R
authors.lastname: Wang
authors.forename: Na
authors.initials: N
authors.lastname: Zhao
authors.forename: Siwen
authors.initials: S
authors.lastname: Li
authors.forename: Jian-Hong
authors.initials: JH
authors.lastname: Fang
authors.forename: Mei-Xian
authors.initials: MX
authors.lastname: Chen
authors.forename: Jine
authors.initials: J
authors.lastname: Yang
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Jia
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Yuan
authors.forename: Shi-Mei
authors.initials: SM
authors.lastname: Zhuang
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000503:physiopathology*; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000502:physiology; D064593:Heterografts; D006801:Humans; D066298:In Vitro Techniques; D008113:Liver Neoplasms / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D035683:MicroRNAs / Q000502:physiology*; D009362:Neoplasm Metastasis / Q000503:physiopathology*; D009389:Neovascularization, Pathologic / Q000503:physiopathology*; D051567:Proto-Oncogene Proteins c-vav / Q000037:antagonists & inhibitors* / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors* / Q000502:physiology; D020764:cdc42 GTP-Binding Protein / Q000037:antagonists & inhibitors* / Q000502:physiology; D020830:rac1 GTP-Binding Protein / Q000502:physiology
chemical_list: C552722:MIRN195 microRNA, human; D035683:MicroRNAs; D051567:Proto-Oncogene Proteins c-vav; C093651:VAV2 protein, human; D042461:Vascular Endothelial Growth Factor A; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein