5-Aza-2′-deoxycytidine, a DNA methylation inhibitor, induces cytotoxicity, cell cycle dynamics and alters expression of DNA methyltransferase 1 and 3A in mouse hippocampus-derived neuronal HT22 cells

2017 ◽  
Vol 80 (22) ◽  
pp. 1222-1229 ◽  
Author(s):  
Jing Yang ◽  
Xiaoli Tian ◽  
Jie Yang ◽  
Junhe Cui ◽  
Shuyuan Jiang ◽  
...  
2006 ◽  
Vol 176 (8) ◽  
pp. 4562-4572 ◽  
Author(s):  
Craig Chappell ◽  
Caroline Beard ◽  
John Altman ◽  
Rudolph Jaenisch ◽  
Joshy Jacob

Pteridines ◽  
2005 ◽  
Vol 16 (4) ◽  
pp. 159-165 ◽  
Author(s):  
Vipen Batra ◽  
Vellappan Kesavan ◽  
Kaushala P. Mishra

Abstract Role of one-carbon transfer agents methyl donors namely folate, choline and methionine in DNA methylation has been the subject of extensive investigation. The methylation pattern of DNA is established during embryogenesis and is subsequently maintained by maintenance methylation activity of the enzyme DNA methyltransferase 1 (dnmt 1). Ionizing radiation is known to extensively damage the DNA. Folate, a water-soluble vitamin, is known to contribute towards repair of damaged DNA due to its role in synthesis of nucleotide base adenine, guanine and thymidylate. Sufficient dietary availability of methyl donors, therefore, might have ability to modify radiation effects. In the present study, modifications in levels of dnmt 1 by g-irradiation followed by methyl donor starvation were observed. Experiments showed a dose and methyl donors starvation dependent attenuation in dnmt 1 activity. Attenuation of dnmt 1 activity was most significant for diet deprived of all the three methyl donors. Ionizing radiation and methyl donor deficiency were observed to act synergistically towards inhibiting dnmt 1 activity. Present results suggested possibility of interaction among folate, methionine and choline deficiency to potentate symptoms of ionizing radiation stress. These enzymatic modifications might contribute to altered DNA methylation after chronic feeding of methyl donor free diets after gamma irradiation. These results suggest that dietary availability of methyl donors and γ-radiation stress might significantly alter the dnmt 1 profile.


2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Marlene Remely ◽  
Franziska Ferk ◽  
Sonja Sterneder ◽  
Tahereh Setayesh ◽  
Sylvia Roth ◽  
...  

Obesity as a multifactorial disorder involves low-grade inflammation, increased reactive oxygen species incidence, gut microbiota aberrations, and epigenetic consequences. Thus, prevention and therapies with epigenetic active antioxidants, (-)-Epigallocatechin-3-gallate (EGCG), are of increasing interest. DNA damage, DNA methylation and gene expression ofDNA methyltransferase 1,interleukin 6, andMutL homologue 1were analyzed in C57BL/6J male mice fed a high-fat diet (HFD) or a control diet (CD) with and without EGCG supplementation. Gut microbiota was analyzed with quantitative real-time polymerase chain reaction. An induction of DNA damage was observed, as a consequence of HFD-feeding, whereas EGCG supplementation decreased DNA damage. HFD-feeding induced a higher inflammatory status. Supplementation reversed these effects, resulting in tissue specific gene expression and methylation patterns ofDNA methyltransferase 1andMutL homologue 1. HFD feeding caused a significant lower bacterial abundance. TheFirmicutes/Bacteroidetesratio is significantly lower in HFD + EGCG but higher in CD + EGCG compared to control groups. The results demonstrate the impact of EGCG on the one hand on gut microbiota which together with dietary components affects host health. On the other hand effects may derive from antioxidative activities as well as epigenetic modifications observed on CpG methylation but also likely to include other epigenetic elements.


2008 ◽  
Vol 22 (6) ◽  
pp. 1981-1992 ◽  
Author(s):  
Xiangsheng Zuo ◽  
Lanlan Shen ◽  
Jean‐Pierre Issa ◽  
Ofir Moy ◽  
Jeffrey S. Morris ◽  
...  

Blood ◽  
2006 ◽  
Vol 107 (3) ◽  
pp. 1174-1177 ◽  
Author(s):  
Michel Herranz ◽  
Juan Martín-Caballero ◽  
Mario F. Fraga ◽  
Jesús Ruiz-Cabello ◽  
Juana Maria Flores ◽  
...  

AbstractGene silencing by CpG island promoter hypermethylation has awakened the interest for DNA demethylating agents as chemotherapy drugs. Zebularine (1-[β-D-ribofuranosil]-1,2-dihydropyrimidin-2-1) has been recently described as a new DNA methylation inhibitor. Here we have studied its effects in a mouse model of radiation-induced lymphomagenesis using nuclear magnetic resonance (NMR) and positron emission tomography (PET). All control animals presented large thymic T lymphomas and died between 4 and 5.5 months. In contrast, 40% (12 of 30) of zebularine-treated animals were still alive after 1 year (Kaplan-Meier P < .001). NMR and PET imaging showed that surviving animals presented a thymus structure/volume similar to normal mice of the same age. Most important, zebularine demonstrated a complete lack of toxicity in nonirradiated control mice. DNA hypomethylation induced by zebularine occurred in association with depletion in extractable DNA methyltransferase 1 protein. Thus, our data support the role of zebularine as a DNA demethylating agent with antitumor activity and little toxicity.


2006 ◽  
Vol 26 (20) ◽  
pp. 7575-7586 ◽  
Author(s):  
Alexander Unterberger ◽  
Stephen D. Andrews ◽  
Ian C. G. Weaver ◽  
Moshe Szyf

ABSTRACT DNA methyltransferase 1 (DNMT1) is an important component of the epigenetic machinery and is responsible for copying DNA methylation patterns during cell division. Coordination of DNA methylation and DNA replication is critical for maintaining epigenetic programming. Knockdown of DNMT1 leads to inhibition of DNA replication, but the mechanism has been unclear. Here we show that depletion of DNMT1 with either antisense or small interfering RNA (siRNA) specific to DNMT1 activates a cascade of genotoxic stress checkpoint proteins, resulting in phosphorylation of checkpoint kinases 1 and 2 (Chk1 and -2), γH2AX focus formation, and cell division control protein 25a (CDC25a) degradation, in an ataxia telangiectasia mutated-Rad3-related (ATR)-dependent manner. siRNA knockdown of ATR blocks the response to DNMT1 depletion; DNA synthesis continues in the absence of DNMT1, resulting in global hypomethylation. Similarly, the response to DNMT1 knockdown is significantly attenuated in human mutant ATR fibroblast cells from a Seckel syndrome patient. This response is sensitive to DNMT1 depletion, independent of the catalytic domain of DNMT1, as indicated by abolition of the response with ectopic expression of either DNMT1 or DNMT1 with the catalytic domain deleted. There is no response to short-term treatment with 5-aza-deoxycytidine (5-aza-CdR), which causes demethylation by trapping DNMT1 in 5-aza-CdR-containing DNA but does not cause disappearance of DNMT1 from the nucleus. Our data are consistent with the hypothesis that removal of DNMT1 from replication forks is the trigger for this response.


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