The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. http://http://dspace.unitus.it:80 2013-05-19T21:06:07Z 2013-05-19T21:06:07Z Belfiore, Maria Cristina Natoni, Alessandro Barzellotti, Roberta Merendino, Nicolò Pessina, Gloria Gualandi, Giampiero http://hdl.handle.net/2067/2068 2011-09-29T23:05:36Z 2006-12-31T23:00:00Z

Title: Involvement of 5-lipoxygenase in survival of Epstein-Barr virus (EBV)-converted B lymphoma cells Authors: Belfiore, Maria Cristina; Natoni, Alessandro; Barzellotti, Roberta; Merendino, Nicolò; Pessina, Gloria; Gualandi, Giampiero Abstract: Epstein–Barr Virus (EBV) is involved in the progression of lymphomas through still unknown mechanism involving increased resistance to induced apoptosis. We show here that in a set of apoptosis-resistant EBV-converted Burkitt’s lymphoma clones, 5- and 12-lipoxygenases (LOXs) are over-expressed. Further investigations on 5-LOX showed that resistance to apoptosis increases parallely with the expression of 5-lipoxygenase (5-LOX). Inhibitors of 5-LOX: (a) decrease peroxides level, indicating that this enzyme promotes the generation of oxidative stress in EBV+ cells, and (b) potently induce apoptosis in the EBV resistant cell line E2R. 5- and 15-HETE, the products of the 5 and 15-LOXs, respectively, counteract 5-LOX inhibitor induced apoptosis, indicating that products of arachidonate metabolism, rather than peroxides, trigger a signal transduction that is required for survival of the EBV-converted cells. These findings suggest that 5- and, to a lesser extent, other LOXs, that are involved in tumor progression of several cell types, may also participate in lymphomagenesis, especially that EBV-mediated. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com

2006-12-31T23:00:00Z Giselico, Luigi Carloni, Manuela Palitti, Fabrizio Mosesso, Pasquale Alfonsi, Alberto Maria Gualandi, Giampiero http://hdl.handle.net/2067/1707 2011-08-08T23:05:28Z 2000-12-31T23:00:00Z

Title: Enhancement of genetic instability in human B cells by Epstein-Barr virus latent infection Authors: Giselico, Luigi; Carloni, Manuela; Palitti, Fabrizio; Mosesso, Pasquale; Alfonsi, Alberto Maria; Gualandi, Giampiero Abstract: The level of genetic instability, as assessed by micronucleus (MN) formation, was higher in Epstein-Barr virus (EBV)-converted B-cell lines with one copy of the EBV genome integrated in each cell than in the parental, EBV-negative, B lymphoma cells. MN induced by EBV latency, as analysed by in situ hybridization, contained mainly centromeric regions, indicating that the presence of EBV affects the segregation of entire chromosomes. The instability was inhibited by treatment with antioxidants. Flow cytometric analysis indicated that there was a higher basal level of peroxides in EBV(+) cells. Direct oxidative stress caused by hydrogen peroxide (which is known to be both apoptogenic and mutagenic) enhanced the number of MN only in an EBV-converted clone. These cells were also resistant to apoptosis, as expected, suggesting that in the parental EBV cells apoptosis may efficiently eliminate cells with genetic damage. These results show for the first time a direct involvement of EBV in the induction of genetic instability, suggesting that it could contribute to tumour progression Description: L'articolo è disponibile sul sito dell'editore: http://mutage.oxfordjournals.org/

2000-12-31T23:00:00Z Fiani, Cinzia Belfiore, Maria Cristina Gualandi, Giampiero Penna, Sabrina Mosesso, Pasquale http://hdl.handle.net/2067/1341 2011-06-30T12:56:46Z 2004-12-31T23:00:00Z

Title: Methyltrioxorhenium catalysed synthesis of highly oxidised aryltetralin lignans with anti-topoisomerase II and apoptogenic activities Authors: Fiani, Cinzia; Belfiore, Maria Cristina; Gualandi, Giampiero; Penna, Sabrina; Mosesso, Pasquale Abstract: A novel and efficient procedure to prepare highly oxidised aryltetralin lignans, such as isopodophyllotoxone and (-)-aristologone derivatives, by oxidation of podophyllotoxin and galbulin with methylrhenium trioxide (MTO) and novel MTO heterogeneous catalysts is reported. It is noteworthy that in the case of isopodophyllotoxone derivatives the functionalisation of the C-4 position of the C-ring and the ring-opening of the D-lactone moiety increased the activity against topoisomerase II while causing the undesired inhibition of tubulin polymerisation to disappear. The novel (-)-aristologone derivatives showed apoptogenic activity against resistant human lymphoma cell lines. Description: L'articolo è disponibile sul sito dell'editore: http://www.sciencedirect.com

2004-12-31T23:00:00Z