title: Nitric oxide donors increase PVR/CD155 DNAM-1 ligand expression in multiple myeloma cells: role of DNA damage response activation.
abstract: BACKGROUND
  DNAX accessory molecule-1 (DNAM-1) is an activating receptor constitutively expressed by macrophages/dendritic cells and by T lymphocytes and Natural Killer (NK) cells, having an important role in anticancer responses; in this regard, combination therapies able to enhance the expression of DNAM-1 ligands on tumor cells are of therapeutic interest. In this study, we investigated the effect of different nitric oxide (NO) donors on the expression of the DNAM-1 ligand Poliovirus Receptor/CD155 (PVR/CD155) in multiple myeloma (MM) cells.
  
  
  METHODS
  Six MM cell lines, SKO-007(J3), U266, OPM-2, RPMI-8226, ARK and LP1 were used to investigate the activity of different nitric oxide donors [DETA-NO and the NO-releasing prodrugs NCX4040 (NO-aspirin) and JS-K] on the expression of PVR/CD155, using Flow Cytometry and Real-Time PCR. Western-blot and specific inhibitors were employed to investigate the role of soluble guanylyl cyclase/cGMP and activation of the DNA damage response (DDR).
  
  
  RESULTS
  Our results indicate that increased levels of nitric oxide can upregulate PVR/CD155 cell surface and mRNA expression in MM cells; in addition, exposure to nitric oxide donors renders myeloma cells more efficient to activate NK cell degranulation and enhances their ability to trigger NK cell-mediated cytotoxicity. We found that activation of the soluble guanylyl cyclase and increased cGMP concentrations by nitric oxide is not involved in the up-regulation of ligand expression. On the contrary, treatment of MM cells with nitric oxide donors correlated with the activation of a DNA damage response pathway and inhibition of the ATM /ATR/Chk1/2 kinase activities by specific inhibitors significantly abrogates up-regulation.
  
  
  CONCLUSIONS
  The present study provides evidence that regulation of the PVR/CD155 DNAM-1 ligand expression by nitric oxide may represent an additional immune-mediated mechanism and supports the anti-myeloma activity of nitric oxide donors.
authors.affiliation: Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Viale Regina Elena 291, 00161, Rome, Italy. cinzia.fionda@uniroma1.it.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Fionda
authors.affiliation: Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Viale Regina Elena 291, 00161, Rome, Italy. mariapia.abruzzese@uniroma1.it.
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Abruzzese
authors.affiliation: Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Viale Regina Elena 291, 00161, Rome, Italy. alessandra.zingoni@uniroma1.it.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Zingoni
authors.affiliation: Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Viale Regina Elena 291, 00161, Rome, Italy. alessandra.soriani@uniroma1.it.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Soriani
authors.affiliation: Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Viale Regina Elena 291, 00161, Rome, Italy. biancamaria.ricci@uniroma1.it.
authors.forename: Biancamaria
authors.initials: B
authors.lastname: Ricci
authors.affiliation: Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Viale Regina Elena 291, 00161, Rome, Italy. rosa.molfetta@uniroma1.it.
authors.forename: Rosa
authors.initials: R
authors.lastname: Molfetta
authors.affiliation: Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Viale Regina Elena 291, 00161, Rome, Italy. rossella.paolini@uniroma1.it.
authors.forename: Rossella
authors.initials: R
authors.lastname: Paolini
authors.affiliation: Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Viale Regina Elena 291, 00161, Rome, Italy. angela.santoni@uniroma1.it.|Istituto Mediterraneo di Neuroscienze Neuromed, Pozzilli, IS, Italy. angela.santoni@uniroma1.it.
authors.forename: Angela
authors.initials: A
authors.lastname: Santoni
authors.affiliation: Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Viale Regina Elena 291, 00161, Rome, Italy. marco.cippitelli@uniroma1.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Cippitelli
mesh_terms: D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis* / Q000235:genetics; D001241:Aspirin / Q000008:administration & dosage / Q000031:analogs & derivatives; D045744:Cell Line, Tumor; D004249:DNA Damage / Q000187:drug effects / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008024:Ligands; D009101:Multiple Myeloma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D009574:Nitro Compounds / Q000008:administration & dosage; D011991:Receptors, Virus / Q000096:biosynthesis* / Q000235:genetics; D014226:Triazenes / Q000008:administration & dosage; D000098862:T Lineage-Specific Activation Antigen 1
chemical_list: C105351:1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene; D000945:Antigens, Differentiation, T-Lymphocyte; D000098862:T Lineage-Specific Activation Antigen 1; D008024:Ligands; C498045:NCX 4040; D009574:Nitro Compounds; D011991:Receptors, Virus; D014226:Triazenes; C066100:poliovirus receptor; D009569:Nitric Oxide; D001241:Aspirin