9 research outputs found

    Role of prothrombotic polymorphisms in successful or unsuccessful aging

    Get PDF
    The study of the genetic profile of centenarians aims to identify the genes and allelic variants which may influence a greater life expectancy and that can be considered as predisposing factors associated to the aging diseases, such as Alzheimer. Centenarians, that represent a cohort of selected survivors, show an hypercoagulability state characterised by striking signs of high coagulation enzyme activity, as directly assessed by the tested higher plasma level of some important factors involved in the haemostasis balance. Anyway, these individuals seem to have a reduced susceptibility to dementia, as well as to cardiovascular events. In this study we analyze the frequencies of Leiden Factor V polymorphism (G1691A), and G20210A of prothrombin (FII) in three cohorts of subjects: patients with Alzheimer\u2019s disease (unsuccessful aging), nonagenarians (successful aging) and young healthy controls, to assess whether allelic variants associated to the modification of haemostatic system function, may play a role in the protection or susceptibility to Alzheimer disease, as well as to reach a successful aging. No significant differences were observed in the frequencies of the three groups studied. These results indicate that the presence or absence of the gene variants examined did not influence the achievement of advanced age and are not risk factors for Alzheimer\u2019s disease. The state of hypercoagulability and the possession of these risk alleles appear to be compatible with the achievement of longevity and are not implied as risk factors in Alzheimer disease development

    Ras inhibition amplifies cisplatin sensitivity of human glioblastoma

    No full text
    Resistance to chemotherapy is a common feature of malignant gliomas. This resistance is mediated by receptor tyrosine kinase (RTK)-regulated signaling. p21-Ras protein is pivotal in the propagation of the signal originated from many RTKs. Our aim was to investigate whether inhibition of Ras pathway affects the response to cisplatin in malignant gliomas. We found an enhanced sensitivity to cisplatin of two glioblastoma cell lines expressing dominant negative Ras. Moreover, DN-Ras expressing cells, implanted in nude mice, resulted in being extremely sensitive to cisplatin. The growth of all the tumors was significantly inhibited by combining DN-Ras adenovirus infection with cisplatin treatment. The majority of glioma cells expressing DN-Ras underwent apoptosis in response to cisplatin. In vivo, DN-Ras alone did not influence the growth of tumors, suggesting that the effects of Ras-inhibition observed in vitro could not be extrapolated in vivo. The survival signal pathway transduced by Ras was essentially mediated by inhibition of caspase-9 cleavage via PI3K/Akt. © 2004 Elsevier Inc. All rights reserved

    p53 genes mutated in the DNA binding site or at a specific COOH-terminal site exert divergent effects on thyroid cell growth and differentiation.

    No full text
    Expression of mutated versions of the p53 gene deranged the differentiation program of thyroid cells and resulted in deregulated growth, Specifically, p53 mutants in several residues of the DNA-binding region induced thyrotropin (TSH) -independent growth and inhibition of the expression of thyroid-specific genes. The loss of the differentiated phenotype invariably correlated with the blockage of the expression of the genes coding for the thyroid transcriptional factors PAX-8 and TTF2. Conversely, thyroid cells transfected with a p53 gene mutated at codon 392, located outside the DNA-binding region, stimulated the expression of differentiation genes in the absence of the TSH, and induced TSH-independent growth. cAMP intracellular levels were higher in thyroid cells transfected with the p53 gene mutated at the 392 site than in the untransfected thyroid cells, but lower in the cells transfected with the other mutated p53 genes. Fra-1 and c-jun were induced by p53, resulting in increased AP-1 levels, The results of this study suggest that p53 exerts effects on cAMP transduction pathway in thyroid cells, which are exquisitely sensitive to cAMP

    p53 genes mutated in the DNA binding site or at a specific COOH-terminal site exert divergent effects on thyroid cell growth and differentiation

    No full text
    Expression of mutated versions of the p53 gene deranged the differentiation program of thyroid cells and resulted in deregulated growth, Specifically, p53 mutants in several residues of the DNA-binding region induced thyrotropin (TSH) -independent growth and inhibition of the expression of thyroid-specific genes. The loss of the differentiated phenotype invariably correlated with the blockage of the expression of the genes coding for the thyroid transcriptional factors PAX-8 and TTF2. Conversely, thyroid cells transfected with a p53 gene mutated at codon 392, located outside the DNA-binding region, stimulated the expression of differentiation genes in the absence of the TSH, and induced TSH-independent growth. cAMP intracellular levels were higher in thyroid cells transfected with the p53 gene mutated at the 392 site than in the untransfected thyroid cells, but lower in the cells transfected with the other mutated p53 genes. Fra-1 and c-jun were induced by p53, resulting in increased AP-1 levels, The results of this study suggest that p53 exerts effects on cAMP transduction pathway in thyroid cells, which are exquisitely sensitive to cAMP
    corecore