title: The microRNA-449 family inhibits TGF-β-mediated liver cancer cell migration by targeting SOX4.
abstract: Modulation of microRNA expression is a potential treatment for hepatocellular carcinoma (HCC). Therefore, the epigenetically regulated microRNA-449 family (miR-449a, miR-449b, miR-449c) was characterized with regards to its functional effects and target genes in HCC.
  
  
  
  After transfection of miR-449a, miR-449b, and/or miR-449c, tumor-relevant functional effects were analyzed using in vitro assays and a xenograft mouse model. Binding specificities, target genes, and regulated pathways of each miRNA were identified by microarray analyses. Target genes were validated by luciferase reporter assays and expression analyses in vitro. Furthermore, target gene expression was analyzed in 61 primary human HCCs compared to normal liver tissue.
  
  
  
  Tumor suppressive effects, binding specificities, target genes, and regulated pathways of miR-449a and miR-449b differed from those of miR-449c. Transfection of miR-449a, miR-449b, and/or miR-449c inhibited cell proliferation and migration, induced apoptosis, and reduced tumor growth to different extents. Importantly, miR-449a, miR-449b, and, to a lesser degree, miR-449c directly targeted SOX4, which codes for a transcription factor involved in epithelial-mesenchymal transition and HCC metastasis, and thereby inhibited TGF-β-mediated cell migration.
  
  
  
  This study provides detailed insights into the regulatory network of the epigenetically regulated miRNA-449 family and, for the first time, describes distinct tumor suppressive effects and target specificities of miR-449a, miR-449b, and miR-449c. Our results indicate that particularly miR-449a and miR-449b may be considered for miRNA replacement therapy to prevent HCC progression and metastasis.
  
  
  
  In this study, we demonstrated that the microRNA-449 family acts as a tumor suppressor in liver cancer by causing cell death and inhibiting cell migration. These effects are caused by downregulation of the oncogene SOX4, which is frequently overexpressed in liver cancer. We conclude that the microRNA-449 family may be a target for liver cancer therapy.
authors.affiliation: Institute of Human Genetics, Hannover Medical School, Hannover, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Sandbothe
authors.affiliation: Institute of Human Genetics, Hannover Medical School, Hannover, Germany.
authors.forename: Reena
authors.initials: R
authors.lastname: Buurman
authors.affiliation: Institute of Human Genetics, Hannover Medical School, Hannover, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Reich
authors.affiliation: Institute of Human Genetics, Hannover Medical School, Hannover, Germany.
authors.forename: Luisa
authors.initials: L
authors.lastname: Greiwe
authors.affiliation: Institute of Human Genetics, Hannover Medical School, Hannover, Germany.
authors.forename: Beate
authors.initials: B
authors.lastname: Vajen
authors.affiliation: Clinic for Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany.
authors.forename: Engin
authors.initials: E
authors.lastname: Gürlevik
authors.affiliation: Institute of Human Genetics, Hannover Medical School, Hannover, Germany.
authors.forename: Vera
authors.initials: V
authors.lastname: Schäffer
authors.affiliation: Institute of Human Genetics, Hannover Medical School, Hannover, Germany.
authors.forename: Marlies
authors.initials: M
authors.lastname: Eilers
authors.affiliation: Clinic for Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Kühnel
authors.affiliation: Chromatin Biology Laboratory, Cancer Epigenetics and Biology Program, Institut d'Investigació Biomèdica de Bellvitge, Barcelona, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Vaquero
authors.affiliation: Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany; Institute of Pathology, University Hospital RWTH Aachen, Heidelberg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Longerich
authors.affiliation: Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Roessler
authors.affiliation: Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Schirmacher
authors.affiliation: Clinic for Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Manns
authors.affiliation: Institute of Human Genetics, Hannover Medical School, Hannover, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Illig
authors.affiliation: Institute of Human Genetics, Hannover Medical School, Hannover, Germany.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Schlegelberger
authors.affiliation: Institute of Human Genetics, Hannover Medical School, Hannover, Germany. Electronic address: skawran.britta@mh-hannover.de.
authors.forename: Britta
authors.initials: B
authors.lastname: Skawran
mesh_terms: D000107:Acetylation; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000473:pathology* / Q000628:therapy; D002465:Cell Movement; D016147:Genes, Tumor Suppressor / Q000502:physiology*; D006657:Histones / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology* / Q000628:therapy; D051379:Mice; D035683:MicroRNAs / Q000502:physiology*; D055751:SOXC Transcription Factors / Q000235:genetics*; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000502:physiology
chemical_list: D006657:Histones; C544530:MIRN449 microRNA, human; D035683:MicroRNAs; C083431:SOX4 protein, human; D055751:SOXC Transcription Factors; D016212:Transforming Growth Factor beta
keywords: Cell migration; Epigenetics; Histone acetylation; Liver cancer; Metastasis; microRNA family; microRNA replacement therapy