Centro Of Oncobiologia Sperimentale Cobs

La Maddalena, Italy

Centro Of Oncobiologia Sperimentale Cobs

La Maddalena, Italy
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Burgio G.,Instituto Telethon Dulbecco | Burgio G.,University of Palermo | Corona D.F.V.,Instituto Telethon Dulbecco | Corona D.F.V.,University of Palermo | And 3 more authors.
Journal of Enzyme Inhibition and Medicinal Chemistry | Year: 2016

Histones and polyamines are important determinants of the chromatin structure. Histones form the core of nucleosome particles and their modification by acetylation of N-terminal tails is involved in chromatin structural changes and transcriptional regulation. Polyamines, including spermidine, are also targets of both cytoplasmic and nuclear acetylation, which in turn alters their affinity for DNA and nucleosomes. Previous studies report the interplay between polyamines metabolism and levels of histone acetylation, but the molecular basis of this effect is still unclear. In this work, we have analyzed the in vitro effect of spermidine on histone H3 acetylation catalyzed by P/CAF, a highly conserved histone acetyltransferase (HAT) (E.C. We have observed that spermidine at very low concentrations activates P/CAF, while it has an inhibitory effect at concentrations higher than 4 μM. In addition, the in vitro bimodal effect of spermidine on histone H3 acetylation was also distinctly observed in vivo on polytene chromosomes of Drosophila melanogaster. We also performed kinetic studies indicating that the activating effect of low spermidine concentrations on P/CAF-HAT activity is based on its involvement as a substrate for P/CAF to produce N8-acetylspermidine that is able in turn to increase the enzyme activity up to four fold. © 2016 Informa UK Limited, trading as Taylor & Francis Group.

Palazzolo G.,ETH Zurich | Albanese N.N.,University of Palermo | Albanese N.N.,Centro Of Oncobiologia Sperimentale Cobs | Di Cara G.,Centro Of Oncobiologia Sperimentale Cobs | And 3 more authors.
Anticancer Research | Year: 2012

Background/Aim: The phenomenon of membrane vesicle-release by neoplastic cells is a growing field of interest in cancer research, due to their potential role in carrying a large array of tumor antigens when secreted into the extracellular medium. In particular, experimental evidence show that at least some of the tumor markers detected in the blood circulation of mammary carcinoma patients are carried by membrane-bound vesicles. Thus, biomarker research in breast cancer can gain great benefits from vesicle characterization. Materials and Methods: Conditioned medium was collected from serum starved MDA-MB-231 sub-confluent cell cultures and exosome-like vesicles (ELVs) were isolated by ultracentrifugation. Ultrastructural analysis of ELVs was performed by transmission electron microscopy (TEM) and the purity of fraction was confirmed by western blotting assays. Proteomic profile of ELVs was carried out by 2 D-PAGE and protein identification performed by MALDI-ToF Mass Spectrometry. Results: On the basis of ultrastructural and immunological characterization, the isolated vesicles have been classified as exosome-like vesicles (ELVs). The proteomic investigation showed a distinctive protein profile of the ELVs, in comparison to the whole cell lisates (WCL) proteome, which could be instrumental for cancer progression. The proteins were clustered into functional categories, according to the current bioinformatics resources and a Venn diagram was constructed based on these clusters. Conclusion: It is reasonable to assume that vesicle production allows neoplastic cells to exert different effects, according to the possible acceptor targets. For instance, vesicles could potentiate the malignant properties of adjacent neoplastic cells or activate non-tumoral cells. Moreover, vesicles could convey signals to immune cells and surrounding stroma cells. The present study may significantly contribute to the knowledge of the vesiculation phenomenon, which is a critical device for trans cellular communication in cancer.

Marengo G.,La Maddalena Hospital | Cancemi P.,University of Palermo | Pucci-Minafra I.,Centro Of Oncobiologia Sperimentale Cobs
Anticancer Research | Year: 2013

Background: The Human Epidermal Growth Factor Receptor 2 (HER-2), overexpressed in 25-30% of breast carcinomas (BC), is the therapeutic target for trastuzumab, a recombinant humanized monoclonal antibody. The initial response to trastuzumab is often followed by drug-insensitivity within one year. Several hypotheses have been raised to explain this event, but the mechanisms behind the responses to trastuzumab are still unclear. Aim: To study the effects of short and prolonged trastuzumab treatment on the proteomic profiles of HER-2- overexpressing SKBR-3 BC cells. Materials and methods: Cells were treated with trastuzumab to obtain sensitive and resistant clones. The drug effects were evaluated at the phenotypical and proteomic levels. Results: In the trastuzumab-resistant cells the expression of a large amount of proteins, initially affected by treatment, reverted to levels of the untreated cells. Conclusion: The results obtained so far illustrate for the first time a large-scale differential protein expression between trastuzumab-treated and untreated cells, and between trastuzumab-sensitive and resistant cells. We believe that the results obtained will help to increase the knowledge of the molecular effects of trastuzumab and will be useful to better-understand the drug resistance mechanisms. © 2013 Anticancer Research.

Cancemi P.,University of Palermo | Cancemi P.,Centro Of Oncobiologia Sperimentale Cobs | Di Cara G.,University of Palermo | Albanese N.N.,University of Palermo | And 7 more authors.
BMC Cancer | Year: 2010

Background: Attempts to reduce morbidity and mortality in breast cancer is based on efforts to identify novel biomarkers to support prognosis and therapeutic choices. The present study has focussed on S100 proteins as a potentially promising group of markers in cancer development and progression. One reason of interest in this family of proteins is because the majority of the S100 genes are clustered on a region of human chromosome 1q21 that is prone to genomic rearrangements. Moreover, there is increasing evidence that S100 proteins are often up-regulated in many cancers, including breast, and this is frequently associated with tumour progression.Methods: Samples of breast cancer tissues were obtained during surgical intervention, according to the bioethical recommendations, and cryo-preserved until used. Tissue extracts were submitted to proteomic preparations for 2D-IPG. Protein identification was performed by N-terminal sequencing and/or peptide mass finger printing.Results: The majority of the detected S100 proteins were absent, or present at very low levels, in the non-tumoral tissues adjacent to the primary tumor. This finding strengthens the role of S100 proteins as putative biomarkers. The proteomic screening of 100 cryo-preserved breast cancer tissues showed that some proteins were ubiquitously expressed in almost all patients while others appeared more sporadic. Most, if not all, of the detected S100 members appeared reciprocally correlated. Finally, from the perspective of biomarkers establishment, a promising finding was the observation that patients which developed distant metastases after a three year follow-up showed a general tendency of higher S100 protein expression, compared to the disease-free group.Conclusions: This article reports for the first time the comparative proteomic screening of several S100 protein members among a large group of breast cancer patients. The results obtained strongly support the hypothesis that a significant deregulation of multiple S100 protein members is associated with breast cancer progression, and suggest that these proteins might act as potential prognostic factors for patient stratification. We propose that this may offer a significant contribution to the knowledge and clinical applications of the S100 protein family to breast cancer. © 2010 Cancemi et al; licensee BioMed Central Ltd.

Cancemi P.,University of Palermo | Cancemi P.,Centro Of Oncobiologia Sperimentale Cobs | Di Cara G.,Centro Of Oncobiologia Sperimentale Cobs | Albanese N.N.,Centro Of Oncobiologia Sperimentale Cobs | And 8 more authors.
Proteomics - Clinical Applications | Year: 2012

Purpose: The present study reports for the first time a large-scale proteomic screening of the occurrence, subcellular localization and relative quantification of the S100A7 protein among a group of 100 patients, clinically grouped for the diagnosis of infiltrating ductal carcinoma (IDC). Experimental design: To this purpose, the methods of differential proteomics, Western blotting, and immunohistochemistry were used. Results: The identity of two isoforms of the protein was assessed by mass spectrometry and immunologically confirmed. Moreover, we proved by immunocytochemical applications the exclusive localization of the protein within the neoplastic cells. The correlation of S100A7 expression levels with the collective profile of cancer patients' proteomics predicted functional interactions, distinct for the two isoforms. The S100A7b isoform was significantly correlated with specific protein clusters (calcium binding, signaling and cell motion, heat shock and folding) and intercrossing pathways (antioxidant, metabolic and apoptotic pathways), while the more acidic isoform was correlated with a narrow number of proteins mainly unrelated to the b isoform. Conclusions and clinical relevance: This study is the first proteomic-based report on S100A7 in a large series of IDC patients. The correlation with in silico data may significantly contribute the knowledge of possible pathways for S100A7, providing novel insights into the mechanism of action of this protein. We suggest that each S100A7 isoform is involved in critical phases of the breast cancer growth and progression, probably through interaction with different partner proteins. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lentini L.,University of Palermo | Melfi R.,University of Palermo | Di Leonardo A.,University of Palermo | Di Leonardo A.,Centro Of Oncobiologia Sperimentale Cobs | And 7 more authors.
Molecular Pharmaceutics | Year: 2014

The presence in the mRNA of premature stop codons (PTCs) results in protein truncation responsible for several inherited (genetic) diseases. A well-known example of these diseases is cystic fibrosis (CF), where approximately 10% (worldwide) of patients have nonsense mutations in the CF transmembrane regulator (CFTR) gene. PTC124 (3-(5-(2-fluorophenyl)-1,2,4-oxadiazol-3-yl)- benzoic acid), also known as Ataluren, is a small molecule that has been suggested to allow PTC readthrough even though its target has yet to be identified. In the lack of a general consensus about its mechanism of action, we experimentally tested the ability of PTC124 to promote the readthrough of premature termination codons by using a new reporter. The reporter vector was based on a plasmid harboring the H2B histone coding sequence fused in frame with the green fluorescent protein (GFP) cDNA, and a TGA stop codon was introduced in the H2B-GFP gene by site-directed mutagenesis. Additionally, an unprecedented computational study on the putative supramolecular interaction between PTC124 and an 11-codon (33-nucleotides) sequence corresponding to a CFTR mRNA fragment containing a central UGA nonsense mutation showed a specific interaction between PTC124 and the UGA codon. Altogether, the H2B-GFP-opal based assay and the molecular dynamics (MD) simulation support the hypothesis that PTC124 is able to promote the specific readthrough of internal TGA premature stop codons. © 2014 American Chemical Society.

Pibiri I.,University of Palermo | Lentini L.,University of Palermo | Tutone M.,University of Palermo | Melfi R.,University of Palermo | And 4 more authors.
European Journal of Medicinal Chemistry | Year: 2016

Ataluren, also known as PTC124, is a 5-(fluorophenyl)-1,2,4-oxadiazolyl-benzoic acid suggested to suppress nonsense mutations by readthrough of premature stop codons in the mRNA. Potential interaction of PTC124 with mRNA has been recently studied by molecular dynamics simulations highlighting the importance of H-bonding and stacking π−π interactions. A series of non-acidic analogues of PTC124 were selected from a large database via a ligand-based virtual screening approach. Eight of them were synthesized and tested for their readthrough activity using the Fluc reporter harboring the UGA premature stop codon. The most active compound was further tested for suppression of the UGA nonsense mutation in the bronchial epithelial IB3.1 cell line carrying the W1282X mutation in the CFTR gene. © 2016 Elsevier Masson SAS

Costa G.,University of Palermo | Barra V.,University of Palermo | Lentini L.,University of Palermo | Cilluffo D.,University of Palermo | And 2 more authors.
Oncotarget | Year: 2016

Aneuploidy, the unbalanced number of chromosomes in a cell, is considered a prevalent form of genetic instability and is largely acknowledged as a condition implicated in tumorigenesis. Epigenetic alterations like DNA hypomethylation have been correlated with cancer initiation/progression. Furthermore, a growing body of evidence suggests the involvement of epigenome-wide disruption as a cause of global DNA hypomethylation in aneuploidy generation. Here, we report that the DNA hypomethylating drug 5-aza-2'-deoxycytidine (DAC), affects the correct ploidy of nearly diploid HCT-116 human cells by altering the methylation pattern of the chromosomes. Specifically, we show that a DACinduced reduction of 5-Methyl Cytosine at the pericentromeric region of chromosomes correlates with aneuploidy and mitotic defects. Our results suggest that DNA hypomethylation leads to aneuploidy by altering the DNA methylation landscape at the centromere that is necessary to ensure proper chromosomes segregation by recruiting the proteins necessary to build up a functional kinetochore.

Taibi G.,University of Palermo | Gueli M.C.,University of Palermo | Nicotra C.M.A.,Centro Of Oncobiologia Sperimentale Cobs | Cocciadiferro L.,ARNAS Civico | Carruba G.,ARNAS Civico
Journal of Enzyme Inhibition and Medicinal Chemistry | Year: 2014

Retinoic acid is regarded as the retinol metabolite that controls proliferation and differentiation of epithelial cells. In the present study, we investigated the potential role of xanthine dehydrogenase (XDH) in retinoic acid biosynthesis in human thyroid glandular cells (HTGC). In particular, we observed that cellular retinoids binding proteins (CRBPs) are also implicated in the biosynthetic pathway leading to retinoic acid formation in primary cultures of HTGC, as we have already reported for human mammary epithelial cells (HMEC). After partial protein purification, the enzyme responsible for retinoic acid biosynthesis was identified and quantified as XDH by immunoassay, by its ability to oxidize xanthine to uric acid and its sensitivity to the inhibitory effect of oxypurinol. The evidence of XDH-driven formation of retinoic acid in HTGC cultures further corroborates the potential role of XDH in retinoic acid biosynthesis in the epithelia. © 2014 Informa UK Ltd. All rights reserved: reproduction in whole or part not permitted.

PubMed | University of Palermo and Centro Of Oncobiologia Sperimentale Cobs
Type: Journal Article | Journal: Stem cell research & therapy | Year: 2016

In regenerative medicine the maintenance of stem cell properties is of crucial importance. Ageing is considered a cause of reduced stemness capability. The limbus is a stem niche of easy access and harbors two stem cell populations: epithelial stem cells and fibroblast-like stem cells. Our aim was to investigate whether donor age and/or long-term culture have any influence on stem cell marker expression and the profiles in the fibroblast-like stem cell population.Fibroblast-like stem cells were isolated and digested from 25 limbus samples of normal human corneo-scleral rings and long-term cultures were obtained. SSEA4 expression and sphere-forming capability were evaluated; cytofluorimetric assay was performed to detect the immunophenotypes HLA-DR, CD45, and CD34 and the principle stem cell markers ABCG2, OCT3/4, and NANOG. Molecular expression of the principal mesenchymal stem cell genes was investigated by real-time PCR. Two-dimensional gel electrophoresis and mass spectrometric sequencing were performed and a stable proteomic profile was identified. The proteins detected were explored by gene ontology and STRING analysis. The data were reported as means SD, compared by Students unpaired t test and considering p < 0.05 as statistically significant.The isolated cells did not display any hematopoietic surface marker (CD34 and CD45) and HLA-DR and they maintained these features in long-term culture. The expression of the stemness genes and the multilineage differentiation under in-vitro culture conditions proved to be well maintained. Proteomic analysis revealed a fibroblast-like stem cell profile of 164 proteins with higher expression levels. Eighty of these showed stable expression levels and were involved in maintenance of the stem gene profile; 84 were differentially expressed and were involved in structural activity.The fibroblast-like limbal stem cells confirmed that they are a robust source of adult stem cells and that they have good plasticity, good proliferative capability, and long-term maintenance of stem cell properties, independently of donor age and long-term culture conditions. Our findings confirm that limbal fibroblast-like stem cells are highly promising for application in regenerative medicine and that in-vitro culture steps do not influence their stem cell properties. Moreover, the proteomic data enrich our knowledge of fibroblast-like stem cells.

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