Search results for "Apoptosi"

New Acylated Triterpene Saponins from Silene fortunei that Modulate Lymphocyte Proliferation

2002

Three new acylated triterpene saponins 1-3, with a quillaic acid as aglycon, were isolated from the roots of Silene fortunei together with a known phytoecdysteroid (20-hydroxyecdysone). The compounds were characterized mainly by a combination of 2D NMR techniques, mass spectrometry, and chemical methods. Saponins 1-3, jenisseensosides C and D (4, 5), and 6 (deacylated form of 2/3 and 4/5) were found to stimulate the proliferation of the Jurkat tumor cell lines at low concentration. At high concentration, 2/3 and 4/5 inhibited the proliferation of the cells and suggested the induction of apoptosis.

Strategie di difesa attivate in risposta a stress, in embrioni di Paracentrotus lividus

2012

Sea urchin embryos are able to activate different defense strategies against stress. This model system allows to investigate numerous phenomena in multipotent cells, which interact among themselves, in their natural position, bypassing the disadvantages of isolated cells, deprived of their normal network. Cadmium (Cd) treatment triggers the accumulation of metal in embryonic cells and the activation of defense systems depending on concentration and exposure time, through the synthesis of heat shock proteins and/or the initiation of apoptosis. Here we show that Paracentrotus lividus embryos exposed to subacute/sublethal concentrations of Cd adopt autophagy as an additional stratagem to safeg…

Developmental defects induced by gadolinium ions in sea urchin embryos of phylogenetically distant species

2015

Gadolinium (Gd) is nowadays an emergent environmental pollutant: it is a metal of the lanthanide series of the elements whose chelates are commonly employed as contrast agents for magnetic resonance imaging and subsequently released into the aquatic environment. Sea urchin embryos are highly sensitive to several kinds of stressors and able to activate different defense strategies. The aim of this study was to analyze the consequences of embryo exposure to sublethal Gd concentrations. We compared the effects of Gd on the development of four phylogenetically distant sea urchin species: two Mediterranean species, Paracentrotus lividus and Arbacia lixula, and two species living in the East coas…

Toxicity induced by Gadolinium ions on sea urchin embryos: comparison among phylogenetically distant species and focus on stress response and skeleto…

2016

Pharmaceuticals are a class of emerging environmental contaminants. Gadolinium (Gd) is a lanthanide metal whose chelates are employed as contrast agents for magnetic resonance imaging, and subsequently released into the aquatic environment. We investigated the effects of exposure to sublethal Gd concentrations on the development of four phylogenetically and geographically distant sea urchin species: two Mediterranean, Paracentrotus lividus and Arbacia lixula, and two from Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Sensitivity to Gd greatly varied, with EC50 ranging from 56 nM to 132 µM across the four species. Measures of the Gd and Ca content inside embryos showed a…

A possible role of autophagy for the execution of apoptosis in cadmium-exposed sea urchin embryos

2012

The sea urchin embryo is a suitable model system that offers an excellent opportunity to investigate different defence strategies activated in stress conditions. We previously showed that cadmium treatment provokes the accumulation of metal in dose- and time-dependent manner in embryonic cells and the activation of defence systems, such as the synthesis of HSPs and/or the initiation of apoptosis. Analysing autophagy, by neutral red, acridine orange and LC3-detection, we demonstrated that Cd-exposed embryos adopt this process as an additional stratagem to safeguard the developmental program. We observed that embryos treated with subletal Cd concentration activate a massive autophagic respons…

Circulating miR-21, miR-146a and Fas ligand respond to postmenopausal estrogen-based hormone replacement therapy--a study with monozygotic twin pairs.

2014

Biological aging is associated with physiological deteriorations and its’ remodeling, which are partly due to changes in the hormonal profile. MicroRNAs are known to post-transcriptionally regulate various cellular processes associated with cell senescence; differentiation, replication and apoptosis. Measured from the serum, microRNAs have the potential to serve as noninvasive markers for diagnostics/prognostics and therapeutic targets. We analysed the association of estrogen-based hormone replacement therapy (HRT) with selected microRNAs and inflammation markers from the serum, leukocytes and muscle tissue biopsy samples obtained from 54-62 year-old postmenopausal monozygotic twins (n=11 p…

Lack of correlation between apoptosis and DNA single-strand breaks in X-irradiated human peripheral blood mononuclear cells in the course of ageing

1998

The dependence on age of both the basal and the X-radiation-induced levels of apoptosis was examined in human peripheral blood mononuclear cells (PBMC). In the same samples, the base value and the extent of induced DNA single-strand breaks were determined, using a sensitive and fast microplate assay. PBMC were isolated from blood of donors of various age groups (20-30, 40-60 and > 70 years of age) and X-irradiated ex vivo using a 6 MV linear accelerator to give a total exposure of 4 Gy. The mean basal levels of apoptosis in PBMC from donors in the 40-60 year age group and the > 70 year age group were found to be only slightly higher (by 20-10%) compared to that of the 20-30 year age group, …

Growth and senescence in the Lowest Metazoa, the porifera: Molecular evolution of apoptotic pathways

1999

Down-Regulation of Ku Autoantigen, DNA-Dependent Protein Kinase, and Poly(ADP-ribose) Polymerase during Cellular Senescence

1997

During aging and cellular senescence mutations accumulate in genomic and mitochondrial DNA. Ku autoantigens, DNA-dependent protein kinase, and poly (ADP-ribose) polymerase have an essential role in DNA damage recognition. Our purpose was to find out whether cellular senescence of fibroblasts affects the protein components that recognize DNA damage and induce the repair process. We compared presenescent and replicatively senescent human WI-38 fibroblasts with each other and with SV-40 immortalized and serum-deficient quiescent WI-38 cells. Our results showed that replicative senescence significantly decreased the nuclear level of both p70 and p86 components of Ku autoantigen. SV-40 immortali…

Synthetic lethal metabolic targeting of cellular senescence in cancer therapy.

2013

Activated oncogenes and anticancer chemotherapy induce cellular senescence, a terminal growth arrest of viable cells characterized by S-phase entry-blocking histone 3 lysine 9 trimethylation (H3K9me3). Although therapy-induced senescence (TIS) improves long-term outcomes, potentially harmful properties of senescent tumour cells make their quantitative elimination a therapeutic priority. Here we use the Eµ-myc transgenic mouse lymphoma model in which TIS depends on the H3K9 histone methyltransferase Suv39h1 to show the mechanism and therapeutic exploitation of senescence-related metabolic reprogramming in vitro and in vivo. After senescence-inducing chemotherapy, TIS-competent lymphomas but …