25 research outputs found

    p53-paralog DNp73 oncogene is repressed by IFNα/STAT2 through the recruitment of the Ezh2 polycomb group transcriptional repressor

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    The DNp73 proteins act as trans-repressors of p53 and p73-dependent transcription and exert both anti-apoptotic activity and pro-proliferative activity. DNp73s are frequently up-regulated in a variety of human cancers, including human hepatocellular carcinomas (HCCs). Increased levels of DNp73 proteins confer to HCC cells resistance to apoptosis and, irrespective to p53 status, a chemoresistant phenotype. Here, we show that interferon (IFN)α down-regulates DNp73 expression in primary human hepatocytes (PHHs) and HCC cell lines. IFNα has been used as pro-apoptotic agent in the treatment of malignancies and there is increasing evidence of IFNα effectiveness in HCC treatment and prevention of recurrence. The precise mechanisms by which class I IFNs exert their anti-proliferative and anti-tumor activity remain unclear. IFNα binding to its receptor activates multiple intracellular signaling cascades regulating the transcription of numerous direct target genes through the recruitment of a complex comprising of STAT1, STAT2 and IFN regulatory factor (IRF)9 to their promoters. We found that, in response to IFNα, the P2p73 promoter undergoes substantial chromatin remodeling. Histone deacetylases (HDACs) replace histone acetyl transferases. STAT2 is recruited onto the endogenous P2p73 promoter together with the polycomb group protein Ezh2, leading to increased H3K27 methylation and transcriptional repression. The reduction of DNp73 levels by IFNα is paralleled by an increased susceptibility to IFNα-triggered apoptosis of Huh7 hepatoma cells. Our results show, for the first time, that IFN-stimulated gene factor 3 recruitment may serve both in activating and repressing gene expression and identify the down-regulation of DNp73 as an additional mechanism to counteract the chemoresistance of liver cancer cells

    At the German coalface: Interdisciplinary collaboration between anthropology and journalism

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    For an understanding of thecurrent ‘coal conundrum’ and the German Energiewende, we applied a collaborative research method involving, anthropological and journalistic practices in villages in East Germany, where the expansion of open-cut lignite mines is contested. We conducted an in-depth study of the local socio-political effects of changing energy production forms at the coalface of prevailing and transforming energy production sites, with human life-worlds as a focal point. Working interdisciplinary with methods of radio journalism and social anthropology helped to provide insights into how national agendas based on political will, techno-economical parameters, social life-worlds and the factor of time intersect. Despite commonalities between journalism and anthropology, this approach to energy research posed methodological challenges. Our work lead to questions of how to collect and make sense of scientifically sustainable information that would allow us to understand the impact of the Energiewende. It resulted in reflections of the limits of building trust, eliciting quotable statements, dealing with scripted narratives, our own roles as interlocutors, the limits of interdisciplinary work and the impact of these factors on interpreting information in larger contexts of global climate debates and energy policies

    Use of the Precipitation Hardening to Improve the Properties of Combustion Engine Pistons Made of Eutectic Silumins

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    The study presents methods to be used for improving the performance parameters of car engine pistons made of EN AC-AlSi12CuNiMg alloy according to the PN-EN 1706: 2011. Pistons of slow sucking and turbocharged engines were researched. A solution heat and ageing treatments were applied according to four variants. Temperatures of the solution heat treatment were: 550 ±5°C; 510°C ±5°C; and alternate: 276 ±5°C/510 ±5°C. The solution time ranged from 6 min to 4 h. Temperatures of the ageing heat treatment were 20°C and 250°C, while the ageing time ranged from 1,5 to 3h. Natural ageing was performed in 5 days. Measurements of hardness HRB and the piston diameters were performed. An improvement in the performance parameters of combustion engines was observed. Three solution heat treatment and ageing variants, allowed to obtain the pistons with hardness equal/higher than pistons of the turbocharged engines. The test results confirmed the possibility of providing a piston with properties exceeding the high load parameters specified by the manufacturer. Further studies will make it possible to improve the effects of the proposed solutions

    Femtosecond Spectral Hole Burning Spectroscopy as a Probe of Exciton Dynamics in Quantum Dots

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    We present measurements of the dynamics of photoexcited excitons in an ensemble of InAs/GaAs self-assembled quantum dots using a femtosecond spectral hole burning technique. We use this technique to examine the exciton spin relaxation and the line shape of optical transitions in the dots

    Femtosecond Spectral Hole Burning Spectroscopy as a Probe of Exciton Dynamics in Quantum Dots

    No full text
    We present measurements of the dynamics of photoexcited excitons in an ensemble of InAs/GaAs self-assembled quantum dots using a femtosecond spectral hole burning technique. We use this technique to examine the exciton spin relaxation and the line shape of optical transitions in the dots
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