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Rossi D.,University of Piemonte Orientale | Fangazio M.,University of Piemonte Orientale | Rasi S.,University of Piemonte Orientale | Vaisitti T.,University of Turin | And 24 more authors.
Blood | Year: 2012

The genetic lesions identified to date do not fully recapitulate the molecular pathogenesis of chronic lymphocytic leukemia (CLL) and do not entirely explain the development of severe complications such as chemorefractoriness. In the present study, BIRC3, a negative regulator of noncanonical NF-κB signaling, was investigated in different CLL clinical phases. BIRC3 lesions were absent in monoclonal B-cell lymphocytosis (0 of 63) and were rare in CLL at diagnosis (13 of 306, 4%). Conversely, BIRC3 disruption selectively affected 12 of 49 (24%) fludarabine-refractory CLL cases by inactivating mutations and/or gene deletions that distributed in a mutually exclusive fashion with TP53 abnormalities. In contrast to fludarabinerefractory CLL, progressive but fludarabine-sensitive patients were consistently devoid of BIRC3 abnormalities, suggesting that BIRC3 genetic lesions associate specifically with a chemorefractory phenotype. By actuarial analysis in newly diagnosed CLL (n ∇ 306), BIRC3 disruption identified patients with a poor outcome similar to that associated with TP53 abnormalities and exerted a prognostic role that was independent of widely accepted clinical and genetic risk factors. Consistent with the role of BIRC3 as a negative regulator of NF-κB, biochemical studies revealed the presence of constitutive noncanonical NF-κB activation in fludarabinerefractory CLL patients harboring molecular lesions of BIRC3. These data identify BIRC3 disruption as a recurrent genetic lesion of high-riskCLL devoid of TP53 abnormalities. © 2012 by The American Society of Hematology.

Logarinho E.,University of Porto | Maffini S.,University of Porto | Maffini S.,Max Planck Institute of Molecular Physiology | Barisic M.,University of Porto | And 8 more authors.
Nature Cell Biology | Year: 2012

Loss of spindle-pole integrity during mitosis leads to multipolarity independent of centrosome amplification. Multipolar-spindle conformation favours incorrect kinetochore-microtubule attachments, compromising faithful chromosome segregation and daughter-cell viability. Spindle-pole organization influences and is influenced by kinetochore activity, but the molecular nature behind this critical force balance is unknown. CLASPs are microtubule-, kinetochore-and centrosome-associated proteins whose functional perturbation leads to three main spindle abnormalities: monopolarity, short spindles and multipolarity. The first two reflect a role at the kinetochore-microtubule interface through interaction with specific kinetochore partners, but how CLASPs prevent spindle multipolarity remains unclear. Here we found that human CLASPs ensure spindle-pole integrity after bipolarization in response to CENP-E-and Kid-mediated forces from misaligned chromosomes. This function is independent of end-on kinetochore-microtubule attachments and involves the recruitment of ninein to residual pericentriolar satellites. Distinctively, multipolarity arising through this mechanism often persists through anaphase. We propose that CLASPs and ninein confer spindle-pole resistance to traction forces exerted during chromosome congression, thereby preventing irreversible spindle multipolarity and aneuploidy. © 2012 Macmillan Publishers Limited. All rights reserved.

Valeri N.,University of Glasgow | Valeri N.,The Institute of Cancer Research | Braconi C.,University of Glasgow | Braconi C.,The Institute of Cancer Research | And 33 more authors.
Cancer Cell | Year: 2014

MicroRNA deregulation is frequent in human colorectal cancers (CRCs), but little is known as to whether itrepresents a bystander event or actually drives tumor progression invivo. We show that miR-135b overexpression is triggered in mice and humans by APC loss, PTEN/PI3K pathway deregulation, and SRC overexpression and promotes tumor transformation and progression. We show that miR-135b upregulation is common in sporadic and inflammatory bowel disease-associated human CRCs and correlates with tumor stage and poor clinical outcome. Inhibition of miR-135b in CRC mouse models reduces tumor growth by controlling genes involved in proliferation, invasion, and apoptosis. We identify miR-135b as a key downsteam effector of oncogenic pathways and a potential target for CRC treatment. © 2014 Elsevier Inc.

Diffuse large B-cell lymphoma (DLBCL) is the most common form of human lymphoma. DLBCL is a heterogeneous disease characterized by different genetic lesions. We herein report the functional characterization of a recurrent gain mapping on chromosome 11q24.3, found in 23% of 166 DLBCL cases analyzed. The transcription factors ETS1 and FLI1, located within the 11q24.3 region, had significantly higher expression in clinical samples carrying the gain. Functional studies on cell lines showed that ETS1 and FLI1 cooperate in sustaining DLBCL proliferation and viability and regulate genes involved in germinal center differentiation. Taken together, these data identify the 11q24.3 gain as a recurrent lesion in DLBCL leading to ETS1 and FLI1 deregulated expression, which can contribute to the pathogenesis of this disease.

Napoli S.,Institute of Oncology Research
Methods in Molecular Biology | Year: 2013

The detailed analysis of noncoding RNA is an upcoming necessity due to a plethora of recently identified components of this class of molecules. The investigation of their structure, directionality, intracellular localization, interaction with other cellular elements is useful to understand the role they play in transcriptional regulation. In this chapter, we describe some techniques, meant to determine very important features of promoter-associated RNAs, in order to clarify their functionality. © Springer Science+Business Media, New York 2013.

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