ABT-737 promotes tBid mitochondrial accumulation to enhance TRAIL-induced apoptosis in glioblastoma cells

To search for novel strategies to enhance the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis pathways in glioblastoma, we used the B-cell lymphoma 2/Bcl2-like 2-inhibitor ABT-737. Here we report that ABT-737 and TRAIL cooperate to induce apoptosis in several glioblastoma cell lines in a highly synergistic manner (combination index <0.1). Interestingly, the concerted action of ABT-737 and TRAIL to trigger the accumulation of truncated Bid (tBid) at mitochondrial membranes is identified as a key underlying mechanism. ABT-737 and TRAIL cooperate to cleave BH3-interacting domain death agonist (Bid) into its active fragment tBid, leading to increased accumulation of tBid at mitochondrial membranes. Coinciding with tBid accumulation, the activation of Bcl2-associated X protein (Bax), loss of mitochondrial membrane potential, release of cytochrome-c and second mitochondria-derived activator of caspase (Smac) into the cytosol and caspase activation are strongly increased in cotreated cells. Of note, knockdown of Bid significantly decreases ABT-737- and TRAIL-mediated Bax activation and apoptosis. Also, caspase-3 silencing reduces ABT-737- and TRAIL-induced Bid cleavage and apoptosis, indicating that a caspase-3-driven, mitochondrial feedback loop contributes to Bid processing. Importantly, ABT-737 profoundly enhances TRAIL-triggered apoptosis in primary cultured glioblastoma cells derived from tumor material, underlining the clinical relevance. Also, ABT-737 acts in concert with TRAIL to suppress tumor growth in an in vivo glioblastoma model. In conclusion, the rational combination of ABT-737 and TRAIL cooperates to trigger tBid mitochondrial accumulation and apoptosis. This approach presents a promising strategy for targeting the apoptosis pathways in glioblastoma, which warrants further investigation

Pathways of survival to oxidative stress: competition between Bcl-2 and Bax and role of NF-kappaB

Buthionine Sulfoximine (BSO) is a well-known inhibitor of glutathione synthesis, producing slow glutathione depletion and oxidative stress; some “responder” cells avoid BSO-induced death by trans-activating the pro-survival protein Bcl-2. Here we show that BSO activates a non-canonical, IκB- and p65-independent NFκB pathway, via a multi-step process leading to the up-regulation of Bcl-2. The slow BSO-induced GSH depletion allows separating two redox-related phases, namely, early thiol disequilibrium, and late frank oxidative stress; each phase contributes to the progressive activation of a p50-p50 homo-dimer. The early phase, coinciding with substantial thiol depletion, produces a cytosolic preparative complex, consisting of p50 and its inter-actor Bcl-3 linked by inter-protein disulfide bridges. The late phase, coinciding with ROS production, is responsible, probably via p38 activation, of nuclear targeting of the complex, and trans-activation of Bcl-2

I vini della DOC Colli Euganei nella ristorazione padovana

The following research has examined the assessment of issues relating to the consumption of CDO (Controlled Denomination of Origin) Colli Euganei (CE) wine in a sample of restaurants of the Padua province. 63% of operators said they always have a minimum number of references of CE denomination as the Fior d’Arancio. The number of references of these wines increases with the average meal price of, indicating that they are more frequent in restaurants showing a certain quality level. Moreover, their average selling price does not differ from the values recorded for other types of wine, though it tends to be lower. The manager or sommelier make the choice of CDO wines on the basis of personal opinions and customer requirements. The purchase of the Doc EC is often done by dealing directly with the producer: this is a further evidence of the strong linkage with the Padua land. We found that the food and wine events, often carried out in collaboration with the Consortium, create a direct contact between the restaurateur and vintner. leading to a consequent increase in purchasing; and this fact is anyway supported by the quality and ease of the product. However, competition from other wine, driven by distribution operators, is remarkable.La seguente ricerca ha preso in esame la valutazione degli aspetti relativi al consumo di vino Doc Colli Euganei presso un campione di ristoranti padovani. Il 63% dei locali ha dichiarato di avere sempre un quantitativo minimo di referenze della denominazione C.E. come il Fior d’Arancio. Le referenze di questi vini aumentano all’aumentate del prezzo medio del pasto, indice che sono anche presenti in ristoranti di un certo livello qualitativo. Inoltre, il loro prezzo medio di vendita non si discosta dai valori registrati per le altre tipologie di vino, anche se tendenzialmente tende a essere più basso. Il gestore o il sommelier effettuano la scelta del vino a denominazione sulla base delle personali opinioni e sulle richieste del cliente. L’acquisto del vino Doc C.E avviene spesso tramite un contatto diretto con il produttore; a conferma della maggior frequenza di consumo nel territorio padovano. E’ così stato riscontrato che le manifestazioni enogastronomiche, spesso effettuate in collaborazione con il Consorzio, creano un contatto diretto tra il ristoratore e il vitivinicoltore portando ad un conseguente incremento degli acquisti; ciò è comunque supportato dalla qualità e dalla facilità del prodotto. Tuttavia, la concorrenza degli altri vini, proposta dalla distribuzione, è notevole

Pathways of survival to oxidative stress: competition between Bcl-2 and Bax and role of NF-kappaB

Buthionine Sulfoximine (BSO) is a well-known inhibitor of glutathione synthesis, producing slow glutathione depletion and oxidative stress; some “responder” cells avoid BSO-induced death by trans-activating the pro-survival protein Bcl-2. Here we show that BSO activates a non-canonical, IκB- and p65-independent NFκB pathway, via a multi-step process leading to the up-regulation of Bcl-2. The slow BSO-induced GSH depletion allows separating two redox-related phases, namely, early thiol disequilibrium, and late frank oxidative stress; each phase contributes to the progressive activation of a p50-p50 homo-dimer. The early phase, coinciding with substantial thiol depletion, produces a cytosolic preparative complex, consisting of p50 and its inter-actor Bcl-3 linked by inter-protein disulfide bridges. The late phase, coinciding with ROS production, is responsible, probably via p38 activation, of nuclear targeting of the complex, and trans-activation of Bcl-2

Oxidation-dependent maturation and survival of explanted blood monocytes via Bcl-2 up-regulation

Monocytes isolated and cultured according to standard procedures from the blood of 22 healthy donors display an activation process, monitored as adhesion and increased exposure of CD11. Starting from very early time points, monocytes undergo a deep redox modulation, i.e., they increase reactive oxygen species (ROS) formation and decrease glutathione content; at the same time, the anti-apoptotic protein Bcl-2 is substantially up-regulated. The cause-effect relationship between these parameters was investigated. On the one side, pharmacological glutathione depletion with BSO further increases ROS formation and Bcl-2 levels. On the other side, scavenging of ROS by Trolox prevents Bcl-2 up-regulation. Two lipoxygenase (LOX) inhibitors (CAPE or AA861) prevent ROS increase and, accordingly, also prevent Bcl-2 up-regulation. All this evidence supports the redox-sensitivity of Bcl-2 regulation. Trolox, CAPE and AA861, i.e., all treatments that abolish ROS increase and prevent Bcl-2 up-regulation, increase the rate of cell loss, whereas BSO, increasing Bcl-2, reduces cell loss and induces chemo-resistance. Thus, explanted healthy monocytes seem to undergo an oxidation-dependent maturation implying increased survival via Bcl-2 up-regulation, perhaps mimicking physiological activation. (C) 2008 Elsevier Inc. All rights reserved

Oxidative, multistep activation of the noncanonical NF-kappa B pathway via disulfide Bcl-3/p50 complex

Buthionine sulfoximine ( BSO) is a well-known inhibitor of glutathione synthesis, producing slow glutathione ( GSH) depletion and oxidative stress; some "responder" cells avoid BSO-induced death by trans-activating the prosurvival protein Bcl-2. Here we show that BSO activates a noncanonical, inhibitory NF-kappa B- and p65-independent NF-kappa B pathway via a multistep process leading to the up-regulation of Bcl-2. The slow BSO-induced GSH depletion allows separation of two redox-related phases, namely, early thiol disequilibrium and late frank oxidative stress; each phase contributes to the progressive activation of a p50-p50 homodimer. The early phase, coinciding with substantial thiol depletion, produces a cytosolic preparative complex, consisting of p50 and its interactor Bcl-3 linked by interprotein disulfide bridges. The late phase, coinciding with reactive oxygen species production, is responsible, probably via p38 activation, for nuclear targeting of the complex and trans-activation of Bcl-2. Cristofanon, S., Morceau, F., Scovassi, A. I., Dicato, M., Ghibelli, L., Diederich, M. Oxidative, multistep activation of the noncanonical NF-kappa B pathway via disulfide Bcl-3/p50 complex. FASEB J. 23, 45-57 ( 2009