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Firenze, Italy

Giglia-Mari G.,Erasmus Medical Center | Giglia-Mari G.,CNRS Institute of Pharmacology and Structural Biology | Giglia-Mari G.,University Paul Sabatier | Zotter A.,Erasmus Medical Center | And 2 more authors.
Cold Spring Harbor Perspectives in Biology | Year: 2011

Structural changes to DNA severely affect its functions, such as replication and transcription, and play a major role in age-related diseases and cancer. A complicated and entangled network ofDNA damage response (DDR) mechanisms, including multiple DNA repair pathways, damage tolerance processes, and cell-cycle checkpoints safeguard genomic integrity. Like transcription and replication, DDR is a chromatin-associated process that is generally tightly controlled in time and space. As DNA damage can occur at any time on any genomic location, a specialized spatio-temporal orchestration of this defense apparatus is required. © 2011 Cold Spring Harbor Laboratory Press.

Conticello S.G.,Core Research Laboratory
Annals of the New York Academy of Sciences | Year: 2012

Organisms minimize genetic damage through complex pathways of DNA repair. Yet a gene family-the AID/APOBECs-has evolved in vertebrates with the sole purpose of producing targeted damage in DNA/RNA molecules through cytosine deamination. They likely originated from deaminases involved in A>I editing in tRNAs. AID, the archetypal AID/APOBEC, is the trigger of the somatic diversification processes of the antibody genes. Its homologs may have been associated with the immune system even before the evolution of the antibody genes. The APOBEC3s, arising from duplication of AID, are involved in the restriction of exogenous/endogenous threats such as retroviruses and mobile elements. Another family member, APOBEC1, has (re)acquired the ability to target RNA while maintaining its ability to act on DNA. The AID/APOBECs have shaped the evolution of vertebrate genomes, but their ability to mutate nucleic acids is a double-edged sword: AID is a key player in lymphoproliferative diseases by triggering mutations and chromosomal translocations in B cells, and there is increasing evidence suggesting that other AID/APOBECs could be involved in cancer development as well. © 2012 New York Academy of Sciences.

Luzzatto L.,Istituto Toscano Tumori | Gianfaldoni G.,Azienda Ospedaliero Universitaria Careggi | Notaro R.,Core Research Laboratory
British Journal of Haematology | Year: 2011

Paroxysmal nocturnal haemoglobinuria (PNH) is a serious form of acquired haemolytic anaemia with several features that make it unique, including the fact that it is caused by clonal expansion, in the context of bone marrow failure, of a haematopoietic stem cell that has a somatic mutation in a gene crucial for the synthesis of glycosylphosphatidylinositol anchors; and that this also produces a life-threatening acquired thrombophilic state. Until recently, the two only main options for patients with PNH were either allogeneic bone marrow transplantation or supportive management, including blood transfusion: both options require some skill and good patient-doctor collaboration. Since the start of this millennium a major advance has been the introduction of eculizumab, a monoclonal antibody that targets the C5 protein of the complement system: blockade of C5 prevents activation of the complement distal pathway, and thus abrogates the complement-mediated intravascular haemolysis that severely plagues patients with PNH. This review outlines an approach to the management of all three major components of the clinical picture of PNH - namely haemolysis, thrombosis and bone marrow failure - based on the literature and on personal experience. We consider specifically how the use of eculizumab has modified other aspects of the management of PNH, and even the pathophysiology itself of this disease. Finally, we develop a treatment algorithm which others might find helpful. © 2011 Blackwell Publishing Ltd.

Santini R.,Core Research Laboratory | Pietrobono S.,Core Research Laboratory | Pandolfi S.,Core Research Laboratory | Montagnani V.,Core Research Laboratory | And 6 more authors.
Oncogene | Year: 2014

Melanoma is one of the most aggressive types of human cancer, characterized by enhanced heterogeneity and resistance to conventional therapy at advanced stages. We and others have previously shown that HEDGEHOG-GLI (HH-GLI) signaling is required for melanoma growth and for survival and expansion of melanoma-initiating cells (MICs). Recent reports indicate that HH-GLI signaling regulates a set of genes typically expressed in embryonic stem cells, including SOX2 (sex-determining region Y (SRY)-Box2). Here we address the function of SOX2 in human melanomas and MICs and its interaction with HH-GLI signaling. We find that SOX2 is highly expressed in melanoma stem cells. Knockdown of SOX2 sharply decreases self-renewal in melanoma spheres and in putative melanoma stem cells with high aldehyde dehydrogenase activity (ALDH high). Conversely, ectopic expression of SOX2 in melanoma cells enhances their self-renewal in vitro. SOX2 silencing also inhibits cell growth and induces apoptosis in melanoma cells. In addition, depletion of SOX2 progressively abrogates tumor growth and leads to a significant decrease in tumor-initiating capability of ALDH high MICs upon xenotransplantation, suggesting that SOX2 is required for tumor initiation and for continuous tumor growth. We show that SOX2 is regulated by HH signaling and that the transcription factors GLI1 and GLI2, the downstream effectors of HH-GLI signaling, bind to the proximal promoter region of SOX2 in primary melanoma cells. In functional studies, we find that SOX2 function is required for HH-induced melanoma cell growth and MIC self-renewal in vitro. Thus SOX2 is a critical factor for self-renewal and tumorigenicity of MICs and an important mediator of HH-GLI signaling in melanoma. These findings could provide the basis for novel therapeutic strategies based on the inhibition of SOX2 for the treatment of a subset of human melanomas. © 2014 Macmillan Publishers Limited. All rights reserved.

Risitano A.M.,University of Naples Federico II | Notaro R.,Core Research Laboratory | Pascariello C.,University of Naples Federico II | Sica M.,Core Research Laboratory | And 9 more authors.
Blood | Year: 2012

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by complement-mediated intravascular hemolysis because of the lack from erythrocyte surface of the complement regulators CD55 and CD59, with subsequent uncontrolled continuous spontaneous activation of the complement alternative pathway (CAP), and at times of the complement classic pathway. Here we investigate in an in vitro model the effect on PNH erythrocytes of a novel therapeutic strategy for membrane-targeted delivery of a CAP inhibitor. TT30 is a 65 kDa recombinant human fusion protein consisting of the iC3b/C3d-binding region of complement receptor 2 (CR2) and the inhibitory domain of the CAP regulator factor H (fH). TT30 completely inhibits in a dose-dependent manner hemolysis of PNH erythrocytes in a modified extended acidified serum assay, and also prevents C3 fragment deposition on surviving PNH erythrocytes. The efficacy of TT30 derives from its direct binding to PNH erythrocytes; if binding to the erythrocytes is disrupted, only partial inhibition of hemolysis is mediated by TT30 in solution, which is similar to that produced by the fH moiety of TT30 alone, or by intact human fH. TT30 is a membrane-targeted selective CAP inhibitor that may prevent both intravascular and C3- mediated extravascular hemolysis of PNH erythrocytes and warrants consideration for the treatment of PNH patients. © 2012 by The American Society of Hematology.

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