Centro Of Biotecnologie Avanzate

Genova, Italy

Centro Of Biotecnologie Avanzate

Genova, Italy
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Pietra G.,University of Genoa | Manzini C.,University of Genoa | Rivara S.,University of Genoa | Vitale M.,IRCCS AOU San Martino IST | And 12 more authors.
Cancer Research | Year: 2012

Natural killer (NK) cells play a key role in tumor immune surveillance. However, adoptive immunotherapy protocols using NK cells have shown limited clinical efficacy to date, possibly due to tumor escape mechanisms that inhibit NK cell function. In this study, we analyzed the effect of coculturing melanoma cells and NK cells on their phenotype and function. We found that melanoma cells inhibited the expression of major NK receptors that trigger their immune function, including NKp30, NKp44, and NKG2D, with consequent impairment of NK cell-mediated cytolytic activity against various melanoma cell lines. This inhibitory effect was primarily mediated by indoleamine 2,3-dioxygenase (IDO) and prostaglandin E2 (PGE2). Together, our findings suggest that immunosuppressive barriers erected by tumors greatly hamper the antitumor activity of human NK cells, thereby favoring tumor outgrowth and progression. ©2012 AACR.

Pasero M.,University of Genoa | Pasero M.,Centro Of Biotecnologie Avanzate | Giovarelli M.,University of Genoa | Giovarelli M.,Centro Of Biotecnologie Avanzate | And 3 more authors.
Cell Reports | Year: 2012

MicroRNAs (miRNAs) are essential regulators of development, physiology, and evolution, and their biogenesis is strictly controlled at multiple levels. Regulatory proteins, such as KSRP, modulate rates and timing of enzymatic reactions responsible for maturation of select miRNAs from their primary transcripts in response to specific stimuli. Here, we show that KSRP silencing in mesenchymal C2C12 cells produces a change in the transcriptome largely overlapping that induced by bone morphogenetic protein 2 (BMP2) signaling activation. This induces osteoblastic differentiation while preventing myogenic differentiation. KSRP silencing- and BMP2-dependent myogenic miRNA (myomiR) maturation blockade is required for osteoblastic differentiation of C2C12 cells. Our results demonstrate that phosphorylated R-SMAD proteins, the transducers of BMP2 signal, associate with phosphorylated KSRP and block its interaction with primary myomiRs. This abrogates KSRP-dependent myomiR maturation, with SMAD4, SMAD5, and SMAD9 silencing being able to rescue KSRP function. Thus, SMAD-induced blockade of KSRP-dependent myomiR maturation is critical for orienting C2C12 cell differentiation toward osteoblastic lineage.

Briata P.,Instituto Nazionale per la Ricerca sul Cancro IST | Chen C.-Y.,University of Alabama at Birmingham | Giovarelli M.,Centro Of Biotecnologie Avanzate | Giovarelli M.,University of Genoa | And 4 more authors.
Frontiers in Bioscience | Year: 2011

KSRP is a single-strand nucleic acids binding protein that affects RNA fate at multiple levels. KSRP modular structure and its complex pattern of posttranslational modifications underpin the interaction with a wide spectrum of RNA target sequences, as well as with other RNA-binding proteins and molecular adaptors. These interactions are important to the regulation of different steps of mRNA metabolism and, in turn, modulate several aspects of cellular proliferation and differentiation. In this review we will discuss in detail KSRP ability to i) promote decay of labile mRNAs interacting with some components of the mRNA decay machinery and ii) favor the maturation of a select group of microRNA precursors.

Pedemonte N.,CNR Institute of Molecular Genetics | Pedemonte N.,Centro Of Biotecnologie Avanzate | Tomati V.,CNR Institute of Molecular Genetics | Sondo E.,CNR Institute of Molecular Genetics | Galietta L.J.V.,CNR Institute of Molecular Genetics
American Journal of Physiology - Cell Physiology | Year: 2010

Cystic fibrosis (CF) is caused by mutations in the CFTR chloride channel. Deletion of phenylalanine 508 (F508del), the most frequent CF mutation, impairs the maturation and gating of the CFTR protein. Such defects may be corrected in vitro by pharmacological modulators named as correctors and potentiators, respectively. We have evaluated a panel of correctors and potentiators derived from various sources to assess potency, efficacy, and mechanism of action. For this purpose, we have used functional and biochemical assays on two different cell expression systems, Fischer rat thyroid (FRT) and A549 cells. The order of potency and efficacy of potentiators was similar in the two cell types considered, with phenylglycine PG-01 and isoxazole UCCF-152 being the most potent and least potent, respectively. Most potentiators were also effective on two mutations, G551D and G1349D, that cause a purely gating defect. In contrast, corrector effect was strongly affected by cell background, with the extreme case of many compounds working in one cell type only. Our findings are in favor of a direct action of potentiators on CFTR, possibly at a common binding site. In contrast, most correctors seem to work indirectly with various mechanisms of action. Combinations of correctors acting at different levels may lead to additive F508del-CFTR rescue. Copyright © 2010 the American Physiological Society.

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