BACKGROUND Polyphyllin I (PPI), a bioactive phytochemical extracted from the Rhizoma of Paris polyphylla, has been reported to exhibit anti-cancer activity. However, the detailed mechanism underlying this remains to be elucidated. METHODS Cell viability and cell cycle distribution were measured using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and flow cytometry ass...

Maintenance of genomic methylation patterns in mammalian somatic cells depends on DNA methyltransferase-1 (Dnmt1). Mouse oocytes and preimplantation embryos lack Dnmt1 but express a variant of this protein called Dnmt1o. We eliminated Dnmt1o by deletion of the oocyte-specific promoter and first exon from the Dnmt1 locus. Homozygous animals were normal, but most heterozygous fetuses of homozygou...

The correlation between the expression of DNA methyltransferase-1 (DNMT1) and estrogen receptor α (ERα), as well as the methylation status of ERα, was analyzed to investigate the clinical significance of DNMT1 and ERα in breast cancer. Substance P immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) were utilized to detect the protein and mRNA expression levels of D...

Resistance of human renal cell carcinoma (RCC) and melanoma to the apoptosis-inducing effects of IFNs was postulated to result from epigenetic silencing of genes by DNA methylation, a common feature of human cancers. To reverse silencing, 5-AZA-deoxycytidine (5-AZA-dC) or selective depletion of DNA methyltransferase 1 (DNMT1) by phosphorothioate oligonucleotide antisense (DNMT1 AS) were employe...

Mammalian cells contain copious amounts of RNA including both coding and noncoding RNA (ncRNA). Generally the ncRNAs function to regulate gene expression at the transcriptional and post-transcriptional level. Among ncRNA, the long ncRNA and small ncRNA can affect histone modification, DNA methylation targeting and gene silencing. Here we show that endogenous DNA methyltransferase 1 (DNMT1) co-p...

Epigenetic mechanisms regulating leukemia stem cells (LSCs) are an attractive target for therapy of blood cancers. Here, we report that conditional knockout of the DNA methyltransferase Dnmt1 blocked development of leukemia, and haploinsufficiency of Dnmt1 was sufficient to delay progression of leukemogenesis and impair LSC self-renewal without altering normal hematopoiesis. Haploinsufficiency ...

The aim of this study was to investigate the effects prenatal stress (PS) on mRNA levels DNA methyltransferases (DNMTs) and histone deacetylases (HDACs) in cerebral cortex hippocampus female rats. PS induced rats with dexamethasone (Dex). From gestation day 14 21, pregnant were injected daily Dex (100 μg/kg) or saline. After birth, at 3 months age, decapitated (n=5). epigenetic mechanisms inves...

Gene activity is regulated by transcriptional and epigenetic mechanisms. A paper in 2005 by Zhang et al.(1) showed that STAT3 binds to the DNA methyl transferase, DNMT1 and their data indicated that STAT3 may cause epigenetic gene silencing by targeting DNMT1 to the PTPN6 promoter. Now, a paper by Lee et al.(2) has fleshed out the mechanism. They provide evidence that acetylation of STAT3 regul...

The overall DNA methylation level sharply decreases from the zygote to the blastocyst stage despite the presence of high levels of DNA methyltransferase (Dnmt1). Surprisingly, the enzyme is localized in the cytoplasm of early embryos despite the presence of several functional nuclear localization signals. We mapped a region in the NH(2)-terminal, regulatory domain of Dnmt1 that is necessary and...

The incidence of cardiovascular diseases is on the rise in world, which poses a significant threat to human health. Myocardial ischemia can cause heart disease. Therefore, it necessary avoid myocardial hypoxia/reoxygenation (H/R) injury attenuate risk present study focuses protective effect isoflurane H/R-induced cell through Sirtuin 6 (SIRT6)/DNA (cytosine-5)-methyltransferase 1 (DNMT1) pathwa...