title: Overexpression of miR-21 promotes an in vitro metastatic phenotype by targeting the tumor suppressor RHOB.
abstract: Metastasis is a multistep process that involves the deregulation of oncogenes and tumor suppressors beyond changes required for primary tumor formation. RHOB is known to have tumor suppressor activity, and its knockdown is associated with more aggressive tumors as well as changes in cell shape, migration, and adhesion. This study shows that oncogenic microRNA, miR-21, represses RHOB expression by directly targeting the 3' untranslated region. Loss of miR-21 is associated with an elevation of RHOB in hepatocellular carcinoma cell lines Huh-7 and HepG2 and in the metastatic breast cancer cell line MDA-MB-231. Using in vitro models of distinct stages of metastasis, we showed that loss of miR-21 also causes a reduction in migration, invasion, and cell elongation. The reduction in migration and cell elongation can be mimicked by overexpression of RHOB. Furthermore, changes in miR-21 expression lead to alterations in matrix metalloproteinase-9 activity. Therefore, we conclude that miR-21 promotes multiple components of the metastatic phenotype in vitro by regulating several important tumor suppressors, including RHOB.
authors.affiliation: Marion Bessin Liver Research Center, Division of Hepatology, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Erin C
authors.initials: EC
authors.lastname: Connolly
authors.forename: Koenraad
authors.initials: K
authors.lastname: Van Doorslaer
authors.forename: Leslie E
authors.initials: LE
authors.lastname: Rogler
authors.forename: Charles E
authors.initials: CE
authors.lastname: Rogler
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism* / Q000556:secondary*; D045744:Cell Line, Tumor; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D016147:Genes, Tumor Suppressor / Q000502:physiology; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology; D009361:Neoplasm Invasiveness / Q000235:genetics / Q000503:physiopathology; D010641:Phenotype; D015854:Up-Regulation / Q000235:genetics; D020743:rhoB GTP-Binding Protein / Q000235:genetics / Q000378:metabolism* / Q000502:physiology
chemical_list: C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D020743:rhoB GTP-Binding Protein