Effect of ELF-EMF on number of apoptotic cells; correlation with reactive oxygen species and HSP.
Garip AI, Akan Z
Acta Biol Hung
61
158-67.
2009
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It is by now accepted that extremely low frequency electromagnetic fields ELF-EMF (0-300 Hz) affect biological systems although the mechanism has not been elucidated yet. In this study the effect of ELFEMF on the number of apoptotic cells of K562 human leukemia cell line induced or not with oxidative stress and the correlation with heat-shock protein 70 (hsp70) levels was investigated. One sample was treated with H 2 O 2 while the other was left untreated. ELF-EMF (1 mT, 50 Hz) was applied for 3 hours. ELF-EMF alone caused a decrease in the number of apoptotic cells and a slight increase in viability. However, it increased the number of apoptotic cells. In cells treated with H 2 O 2 . hsp70 and reactive oxygen species (ROS) levels were increased by ELF-EMF. These results show that the effect of ELF-EMF on biological systems depends on the status of the cell: while in cells not exposed to oxidative stress it is able to decrease the number of apoptotic cells by inducing an increase in hsp levels, it increases the number of apoptotic cells in oxidative stress-induced cells. | 20519170
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Transcriptional regulation of livin by beta-catenin/TCF signaling in human lung cancer cell lines.
Dong Yuan,Liqun Liu,Dayong Gu
Molecular and cellular biochemistry
306
2007
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Wnt/beta-catenin signaling emerged as a critical pathway in human lung carcinogenesis by regulating the livin promoter activity. This study clarified that livin was a direct target gene of beta-catenin/TCF signaling pathway in non-small cell lung cancer (NSCLC) cells. First, we observed that livin mRNA was up-regulated by LiCl treatment in culture of A549 and 103H cell lines. In addition we found that the activity of livin promoter is increased considerably by activation of beta-catenin and could be blocked by a dominant negative form of DeltaTCF4. Furthermore, we identified a TCF binding site located at -1476/-1470 of the livin promoter which is crucial to the response of beta-catenin. At last, chromatin immunoprecipitation (ChIP) assay was performed and the result indicated that beta-catenin/TCF complex binds to the putative TCF binding site of the livin promoter in A549 and 103H cell lines. Our results suggest that livin is transcriptionally regulated by beta-catenin/TCF signaling in human NSCLC cell lines. | 17660948
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