title: EIF6 over-expression increases the motility and invasiveness of cancer cells by modulating the expression of a critical subset of membrane-bound proteins.
abstract: BACKGROUND
  Eukaryotic Initiation factor 6 (eIF6) is a peculiar translation initiation factor that binds to the large 60S ribosomal subunits, controlling translation initiation and participating in ribosome biogenesis. In the past, knowledge about the mechanisms adopted by the cells for controlling protein synthesis by extracellular stimuli has focused on two translation initiation factors (eIF4E and eIF2), however, recent data suggest eIF6 as a newcomer in the control of downstream of signal transduction pathways. eIF6 is over-expressed in tumors and its decreased expression renders cells less prone to tumor growth. A previous work from our laboratory has disclosed that over-expression of eIF6 in transformed cell lines markedly increased cell migration and invasion.
  
  
  METHODS
  Here, we performed a quantitative proteomic analysis of membrane-associated proteins in A2780 ovarian cancer cells over-expressing eIF6. Differentially expressed proteins upon eIF6 overproduction were further investigated in silico by Ingenuity Pathway Analysis (IPA). RT-qPCR and Western blot were performed in order to validate the proteomic data. Furthermore, the effects of a potent and selective inhibitor ML-141 in A2780 cells were evaluated using transwell migration assay. Finally, we explored the effects of eIF6 over-expression on WM793 primary melanoma cell lines.
  
  
  RESULTS
  We demonstrated that: (i) the genes up-regulated upon eIF6 overproduction mapped to a functional network corresponding to cellular movements in a highly significant way; (ii) cdc42 plays a pivotal role as an effector of enhanced migratory phenotype induced upon eIF6 over-expression; (iii) the variations in abundance observed for cdc42 protein occur at a post-transcriptional level; (iv) the increased cell migration/invasion upon eIF6 over-expression was generalizable to other cell line models.
  
  
  CONCLUSIONS
  Collectively, our data confirm and further extend the role of eIF6 in enhancing cell migration/invasion. We show that a number of membrane-associated proteins indeed vary in abundance upon eIF6 over-expression, and that the up-regulated proteins can be located within a functional network controlling cell motility and tumor metastasis. Full understanding of the role eIF6 plays in the metastatic process is important, also in view of the fact that this factor is a potentially druggable target to be exploited for new anti-cancer therapies.
authors.affiliation: Istituto Pasteur-Fondazione Cenci Bolognetti and Department of Cellular Biotechnologies and Haematology, Sapienza University of Rome, Via Regina Elena 324, 00161, Rome, Italy. michela.pinzaglia@uniroma1.it.
authors.forename: Michela
authors.initials: M
authors.lastname: Pinzaglia
authors.affiliation: L. Spallanzani National Institute for Infectious Diseases, IRCCS, Via Portuense 292, 00149, Rome, Italy. claudia.montaldo@inmi.it.
authors.forename: Claudia
authors.initials: C
authors.lastname: Montaldo
authors.affiliation: Istituto Pasteur-Fondazione Cenci Bolognetti and Department of Cellular Biotechnologies and Haematology, Sapienza University of Rome, Via Regina Elena 324, 00161, Rome, Italy. arya84@hotmail.it.
authors.forename: Dorina
authors.initials: D
authors.lastname: Polinari
authors.affiliation: European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg, 69117, Germany. mattei@embl.de.
authors.forename: Mattei
authors.initials: M
authors.lastname: Simone
authors.affiliation: Department of Life and Environmental Science, Polytechnic University of Marche, Via Brecce Bianche, 60131, Ancona, Italy. a.lateana@univpm.it.
authors.forename: Anna
authors.initials: A
authors.lastname: La Teana
authors.affiliation: Istituto Pasteur-Fondazione Cenci Bolognetti and Department of Cellular Biotechnologies and Haematology, Sapienza University of Rome, Via Regina Elena 324, 00161, Rome, Italy. tripodi@bce.uniroma1.it.|L. Spallanzani National Institute for Infectious Diseases, IRCCS, Via Portuense 292, 00149, Rome, Italy. tripodi@bce.uniroma1.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Tripodi
authors.affiliation: Istituto Pasteur-Fondazione Cenci Bolognetti and Department of Cellular Biotechnologies and Haematology, Sapienza University of Rome, Via Regina Elena 324, 00161, Rome, Italy. carmine.mancone@uniroma1.it.|L. Spallanzani National Institute for Infectious Diseases, IRCCS, Via Portuense 292, 00149, Rome, Italy. carmine.mancone@uniroma1.it.
authors.forename: Carmine
authors.initials: C
authors.lastname: Mancone
authors.affiliation: Istituto Pasteur-Fondazione Cenci Bolognetti and Department of Cellular Biotechnologies and Haematology, Sapienza University of Rome, Via Regina Elena 324, 00161, Rome, Italy. londei@bce.uniroma1.it.
authors.forename: Paola
authors.initials: P
authors.lastname: Londei
authors.affiliation: Istituto Pasteur-Fondazione Cenci Bolognetti and Department of Cellular Biotechnologies and Haematology, Sapienza University of Rome, Via Regina Elena 324, 00161, Rome, Italy. benelli@bce.uniroma1.it.
authors.forename: Dario
authors.initials: D
authors.lastname: Benelli
mesh_terms: D002465:Cell Movement / Q000502:physiology; D039642:Eukaryotic Initiation Factors / Q000096:biosynthesis*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis*; D009361:Neoplasm Invasiveness / Q000473:pathology
chemical_list: C109284:EIF6 protein, human; D039642:Eukaryotic Initiation Factors; D008565:Membrane Proteins