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Apoptotic DNA Fragmentation (apoptotic + dna_fragmentation)
Selected AbstractsCell death mechanisms in neurodegenerationJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 1 2001K. A. Jellinger Abstract Progressive cell loss in specific neuronal populations often associated with typical cytoskeletal protein aggregations is a pathological hallmark of neurodegenerative disorders, but the nature, time course and molecular causes of cell death and their relation to cytoskeletal pathologies are still unresolved. Apoptosis or alternative pathways of cell death have been discussed in Alzheimer's disease and other neurodegenerative disorders. Apoptotic DNA fragmentation in human brain as a sign of neuronal injury is found too frequent as to account for continous neuron loss in these slowly progressive processes. Morphological studies revealed extremely rare apoptotic neuronal death in Alzheimer's disease but yielded mixed results for Parkinson's disease and other neurodegenerative disorders. Based on recent data in human brain, as well as in animal and cell culture models, a picture is beginning to emerge suggesting that, in addition to apoptosis, other forms of programmed cell death may participate in neurodegeneration. Better understanding of the molecular players will further elucidate the mechanisms of cell death in these disorders and their relations to cytoskeletal abnormalities. Susceptible cell populations in a proapoptotic environment show increased vulnerability towards multiple noxious factors discussed in the pathogenesis of neurodegeneration. In conclusion, although many in vivo and in vitro data are in favor of apoptosis involvement in neurodegenerative processes, there is considerable evidence that very complex events may contribute to neuronal death with possible repair mechanisms, the elucidation of which may prove useful for future prevention and therapy of neurodegenerative disorders. [source] Cyclosporine A and its non-immunosuppressive derivative NIM811 induce apoptosis of malignant melanoma cells in in vitro and in vivo studiesINTERNATIONAL JOURNAL OF CANCER, Issue 1 2005Iwona Ciechomska Abstract Advanced melanoma is a highly malignant tumor with an increasing incidence that has a poor prognosis due to resistance to common therapeutic strategies. We have demonstrated previously that cyclosporine A (CsA) induces apoptosis of rat glioma cells, reactive astrocytes, and fibroblasts. In our present study, we investigated effects of CsA and its nonimmunosuppressive derivative NIM811 on survival of human and murine melanoma cells. We demonstrated that CsA and NIM811 affect survival of human and murine melanoma cells and induce morphological changes, alterations in nuclear morphology and an internucleosomal DNA fragmentation, consistent with an apoptotic type of death. Western blot analysis showed an activation of caspases 9, 7, 3 and PARP cleavage detectable at 24 hr after exposure of human melanoma cells to the drugs. CsA and NIM811 induced a significant increase in subG1 population of murine B16F10 melanoma cells indicative of apoptotic DNA fragmentation. Studies in murine model of melanoma showed that NIM811, but not CsA, retards tumor progression and significantly decreases tumor volume after intratumoral application. Our findings indicate that CsA and its derivatives may be new candidates for the treatment of melanoma patients. © 2005 Wiley-Liss, Inc. [source] CD137 and CD137 ligand constitutively coexpressed on human T and B leukemia cells signal proliferation and survivalINTERNATIONAL JOURNAL OF CANCER, Issue 3 2004Carla Palma Abstract CD137, a member of the tumor necrosis factor receptor family, provides expansion and survival signal to T cells. Its ligand, CD137L, in addition to its ability to costimulate T cells, signals back into antigen presenting cells promoting their activation and differentiation. Recently, CD137 has been proposed as a therapeutic target to improve and sustain anticancer immune response. Several activated T leukemia and B lymphoma cell lines expressed CD137 or CD137L, respectively, and soluble CD137L has been found in sera of leukemia patients. However, the functionality and role of these costimulatory molecules in hematologic malignancies are until now unknown. Interestingly, we observed constitutive CD137 and CD137L coexpression on both human T and B leukemia cell lines. The constitutive CD137 expression on unstimulated T or B leukemia cells presents some differences compared to CD137 expressed on PMA/ionomycin-activated T leukemia cells. Surprisingly, in spite of the low expression level, both tumor CD137 and CD137L molecules signaled in T and B leukemia cells inducing proliferation and prolonging survival. In addition, CD137/CD137L system ligation opposed the anticancer drug cytotoxic effects, reducing the apoptotic DNA fragmentation and stimulating proliferation of doxorubicin-escaped leukemia cells. Although the role of leukemia CD137/CD137L system in vivo is unknown, these data suggest that these costimulatory molecules might confer an advantage to hematologic tumors promoting survival, sustaining cellular growth and contributing to drug resistance. © 2003 Wiley-Liss, Inc. [source] Effect of berberine on proliferation, cell cycle and apoptosis in HeLa and L1210 cellsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 8 2003a Jantová Previous studies on the anticancer activity of protoberberine alkaloids against a variety of cancer cell lines were extended to human tumour HeLa and murine leukemia L1210 cell lines. An attempt was also made to investigate the relationship between the cytotoxic activity of berberine and its molecular mechanism of action. Cytotoxicity was measured in-vitro using a primary biochemical screening according to Oyama and Eagle, and the growth inhibition assay. The in-vitro cytotoxic techniques were complemented by cell cycle analysis and determination of apoptotic DNA fragmentation in L1210 cells. Berberine acted cytotoxically on both tumour cell lines. The sensitivity of leukemia L1210 cells to the berberine was higher than that of HeLa cells. The IC100 was below 100 ,g mL,1 for HeLa cells and approached a 10 , mL,1 limit for the leukemia L1210 cells. For both cell lines the IC50 was found to be less than 4 ,g mL,1, a limit put forward by the National Cancer Institute (NCI) for classification of the compound as a potential anticancer drug. In L1210 cells treated with 10,50 , mL,1 berberine, G0/G1 cell cycle arrest was observed. Futhermore, a concentration-dependent decrease of cells in S phase and increase in G2/M phase was detected. In addition, apoptosis detected as sub-G0 cell population in cell cycle measurement was proved in 25,100 ,g mL,1 berberine-treated cells by monitoring the apoptotic DNA fragmentation (DNA ladder) using agarose gel electrophoresis. [source] Human lysosomal DNase II, contains two requisite PLD-signature (HxK) motifs: Evidence for a pseudodimeric structure of the active enzyme speciesPROTEIN SCIENCE, Issue 1 2007Patrick Schäfer Abstract Lysosomal DNase II, is essential for DNA waste removal and auxiliary apoptotic DNA fragmentation in higher eukaryotes. Despite the key role of this enzyme, little is known about its structure,function relationships. Here, mutational and biochemical analyses were used to characterize human DNase II, variants expressed in mammalian cells. The resulting data strongly support the hypothesis that the enzyme is a monomeric phospholipase D,family member with a pseudodimeric protein fold. According to our results, DNase II, contains two requisite PLD-signature motifs (113HTK115 and 295HSK297) in the N- and C-terminal subdomains, respectively, that together form a single active site. Based on these data, we present an experimentally validated structural model of DNase II,. 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