Acetaminophen protects hippocampal neurons and PC12 cultures from amyloid beta-peptides induced oxidative stress and reduces NF-kappaB activation

The present findings show that an atypical non-steroidal anti-inflammatory drug, such as acetaminophen, retains the ability to recover amyloid beta-peptides driven neuronal apoptosis through the impairment of oxidative stress. Moreover, this compound reduces the increased NF-kappaB binding activity, which occurs in these degenerative conditions. Therapeutic interventions aimed at reducing the inflammatory response in Alzheimer's disease (AD) recently suggested the application of non-steroidal anti-inflammatory drugs. Although the anti-inflammatory properties of acetaminophen are controversial, it emerged that in an amyloid-driven astrocytoma cell degeneration model acetaminophen proved to be effective. On these bases, we analyzed the role of acetaminophen against the toxicity exerted by different Abeta-peptides on rat primary hippocampal neurons and on a rat pheochromocytoma cell line. We found a consistent protection from amyloid beta-fragments 1-40 and 1-42-induced impairment of mitochondrial redox activity on both cell cultures, associated with a marked reduction of apoptotic nuclear fragmentation. An antioxidant component of the protective activity emerged from the analysis of the reduction of phospholipid peroxidation, and also from a significant reduction of cytoplasmic accumulation of peroxides in the pheochromocytoma cell line. Moreover, activation of NF-kappaB by amyloid-derived peptides was greatly impaired by acetaminophen pre-treatment in hippocampal cells. This evidence points out antioxidant and anti-transcriptional properties of acetaminophen besides the known capability to interfere with inflammation within the central nervous system, and suggests that it can be exploited as a possible therapeutic approach against AD.

Inhibition of nuclear factor-kappaB activation induces apoptosis in cerebellar granule cells

The nuclear factor (NF)-kappaB family of transcription factors plays important roles in the regulation of many activities of neuronal cells, such as synaptic transmission, inflammation, neuroprotection, and neurotoxicity. In resting cells, NF-kappaB activity is present both in the cytoplasm, as an inducible-inactive complex, and in the nucleus, as a constitutive form. Regulation of its inducible activity relies on processing of IkappaB(s), which occurs through the proteasome. Here we show that in cerebellar granule cells (CGC) the induction of apoptosis, by potassium withdrawal (5 mM KCl), decreases the amount of nuclear NF-kappaB. To understand whether NF-kappaB was required for CGC survival, these cells, maintained under depolarizing conditions (25 mM KCl and serum), were treated with proteasome inhibitors. The results show that these treatments reduce the nuclear amount of NF-kappaB and increase p65 cytoplasmic levels, a process partially regulated via IkappaBalpha degradation. These events are also associated with an impairment in CGC survival, with changes in nuclear morphology, induction of DNA laddering, and oligonucleosome formation, consistent with apoptosis. According to the K+ deprivation model, PSI-induced apoptosis is reversed by inhibitors of transcription and translation as well as by specific caspase inhibitors. Together our results show an important role for NF-kappaB in maintaining CGC survival. Indeed, under conditions of mild depolarization (K25) necessary for CGC survival, NF-kappaB is distributed between cytosol and nucleus, whereas, under apoptotic conditions (K5), it is depleted from the nucleus, such as after proteasome inhibitor treatment. Therefore, NF-kappaB nuclear deprivation is involved in the induction of CGC apoptosis.

Prevalence and molecular characterization of Aeromonas spp. in ready-to-eat foods in Italy

A survey was carried out in Italy to ascertain the prevalence of Aeromonas spp. in ready-to-eat foods (vegetables, cheeses, meat products, and ice creams) and the level of molecular heterogeneity of the isolates found by macrorestriction analysis of genomic DNA with pulsed-field gel electrophoresis (PFGE). In total, 46 (14.4%) of the 320 food samples examined were found positive for Aeromonas spp. The highest percentages of isolation were discovered in vegetables, particularly lettuce (45.0%), endive (40.0%), and rucola (20.0%). Ricotta was the only cheese type analyzed that showed a high frequency of isolation (45.0%). Among meat products, salami and raw ham (25.0% of samples positive) and, to a lesser extent, baloney (5.0%) were found positive for Aeromonas spp. Aeromonas hydrophila was the most common isolate from foods of animal origin, whereas Aeromonas caviae was the dominant species in vegetables. No motile aeromonads were found in ice cream samples. Aeromonas isolates showed a high level of genetic heterogeneity, because 24 PFGE patterns were identified among 27 A. hydrophila strains and 20 PFGE patterns were found in 23 A. caviae isolates. In conclusion, consumers of ready-to-eat foods in Italy are regularly exposed to many genetically distinct strains of A. hydrophila and A. caviae without evident signs of malaise, and therefore, few of these strains, if any, are likely to be pathogenic.

DDP-induced cytotoxicity is not influenced by p53 in nine human ovarian cancer cell lines with different p53 status

Nine human ovarian cancer cell lines that express wild-type (wt) or mutated (mut) p53 were used to evaluate the cytotoxicity induced by cisplatin (DDP). The concentrations inhibiting the growth by 50% (IC50) were calculated for each cell line, and no differences were found between cells expressing wt p53 and mut p53. Using, for each cell line, the DDP IC50, we found that these concentrations were able to induce an increase in p53 levels in all four wt-p53-expressing cell lines and in one out of five mut-p53-expressing cell lines. WAF1 and GADD45 mRNAs were also increased by DDP treatment, independently of the presence of a wt p53. Bax levels were only marginally affected by DDP, and this was observed in both wt-p53- and mut-p53-expressing cells. DDP-induced apoptosis was evident 72 h after treatment, and the percentage of cells undergoing apoptosis was slightly higher for wt-p53-expressing cells. However, at doses near the IC50, the percentage of apoptotic cells was less than 20% in all the cell lines investigated. We conclude that the presence of wt p53 is not a determinant for the cytotoxicity induced by DDP in human ovarian cancer cell lines.

Endogenous tumor necrosis factor enhances topoisomerase II inhibitors activity in human ovarian cancer cell lines

In this study, we demonstrated that tumor necrosis factor (TNF), secreted endogenously by four human ovarian cancer cell lines (A2774, IGROV-1, OVCAR-8, SW626), is biologically active against L929 cells and its activity is specifically inhibited by anti-TNF antibodies. Its endogenous production is increased by treatment for 24 h with phorbol myristate acetate (PMA)/ Ionomycin (Iono). All cell lines express TNF high-affinity receptors and release only 60-kdalton soluble TNF receptor, both spontaneously and after stimulation with PMA/Iono. TNF endogenously secreted by human ovarian cancer cell lines is very efficient in potentiating the activity of DNA topoisomerase II inhibitors (doxorubicin, mitoxantrone, VP16). The activity of vinblastine and bleomycin is not potentiated and, more interestingly, cisplatin's activity is inhibited. In 24-h PMA/Iono-stimulated A2774 cells, mitoxantrone specifically generated more cleavable complexes than in unstimulated cells. This result could provide an important tool in the therapy of human ovarian cancer secreting TNF protein, previously considered as a negative prognostic factor.

Interferon-alpha or beta potentiate platinum analogous in human glioblastoma cell lines

The effect of interferon-alpha or beta on platinum analogues [cisplatin (CDDP) and carboplatin] cytotoxicity was studied in four glioblastoma cell lines (U373MG, T98G, A172 and U118Mg). All cell lines were strongly resistant to the cytotoxic effect of CDDP or carboplatin. Although both interferons were not cytotoxic in all cell lines, they were able to significantly increase the cell platinum-sensitivity. Specifically interferon-alpha increased the magnitude of CDDP-induced DNA interstrand crosslinks. Our findings suggest that interferons are able to induce a very strong potentiation of platinum analogues cytotoxicity in drug-resistant human glioma cell lines.